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RESEARCH HIGHLIGHTS

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O F TH E

NATIONAL BUREAU OF STANDARDS

The

THE PEN

STATE COLLEGE^P^^&^l^ANlA

ANNUAL REPORT

NBS

I often say that when you can measure what you
are speaking about and express it in numbers you
know something about it; but when you cannot
measure it, when you cannot express it in numbers,
your knowledge is of a meaner and unsatisfactory
kind; it may be the be|,innin^ of knowledge, but
you Have seareely, in your tbou|KtSj advaneed t®
the stale of science, whatever the matter may ht,

Lord Kilvin HIS,

In this sixtieth year of the National Bureau of Standards,
Lord Kelvin's perceptive statement ffittlt be lead in terms of
its critical application to every significant area of modern
science and technology, Our ability to control or to make
use of nature's resources is directly dependent upon our quan-
titative understanding of the physical world, and on our
ability to practice precision measurement, The gaps between
basic data and applied research and between research and
development are bridged by precision knowledge and ad-
vanced measurement processes, Measurement thus serves
as the languap of science as well as the means for applying
research for the advancement of our general welfare, From
this, wc derive the inescapable conclusion that excellence in
the science of physical measurement is au essential founda-
tion for leadership in the progress of science and technology,

A, V. Astin, Director^ NBS,

UNITED STATES DEPARTMENT OF COMMERCE

Luther H. Hodges, Secretary
Hickman Price, Jr., Assistant Secretary for Domestic Affairs

NATIONAL BUREAU OF STANDARDS
A. V. Astin, Director

1961
Research Highlights

of the

National Bureau of Standards

Annual Report, Fiscal Year 1961

December 1961

Miscellaneous Publication 242

For sale by the Superintendent of Documents, U. S. Government Printing Office
Washington 25, D. C. - Price 75 cents

The National Bureau of Standards, Washington, D.C, laboratories (top) and
Boulder, Colorado, laboratories (bottom).

Contents

Page

General review 1

Progress in measurement standards 2

Studies of matter and materials 5

Astrophysical and plasma physics research 6

Radio propagation research 8

Data processing systems 9

Calibration, testing, and standard samples 9

Cooperative activities 14

Administrative activities 17

Publications 13

Highlights of the research program 20

2.1. Physics, electronics, and measurement standards 20

2.1.1. Metrology 20

Wavelength standard of length 21

Frustrated total reflection 22

Mass standards 22

Weighing techniques 22

Ultraviolet wavelength standard developed 23

Filters selected for checking color measurement equipment. . 23

Irradiance meters calibrated 23

Color names standardized 23

Artificial daylight standard 24

Color-rendering index developed 24

Specular reflectance standard 25

Color scale for vegetable oils 25

Refractive indices provided 25

Image analysis 25

Ray-tracing equations developed 26

Interference microscope techniques 26

Absolute testing of wavefront shapes 26

Calibration of crash flight record 26

Photographic density measurements 27

2.1.2. Mechanics 28

Measurement of vibration amplitudes 28

Calibration of microphones 28

Recording on magnetic tapes 29

Analysis of transients 29

Infrasonic waves in the atmosphere and in the earth 29

Ultra-high-pressure measurements 30

Study of convective currents in water 31

Internal waves in water with uniform density gradients. ... 31

Force measurements 31

Clamping force of high strength aircraft bolts 32

Mechanical properties of materials at elevated temperatures . 32

Rheology of liquids 33

High-temperature thermocouples 33

Catalytic effects of thermocouple materials 34

Hypervelocity missile in a combustible gas 35

Fuel flowrate studies 35

2.1.3. Electricity 36

Absolute measurement of resistance 36

Standard cells under vibration 36

Electrode kinetics 37

Electrical properties of molecular solvents at high tempera-
ture 38

Metal oxide solubilities in molten salts 38

Metal-molten salt interactions and stoichiometry 38

Differential thermocouple voltmeter 38

Magnetism 39

Analysis of the melting point of polychlorotrifluoroethylene . 40
Analysis of the dielectric properties of polychlorotrifluoro-
ethylene 40

Dielectric properties of polyparachlorostyrene and polymeta-

chlorostyrene 41

• • •
HI

2. Highlights of the research program — Continued

2.1. Physics, electronics, and measurement standards — Continued Page

2.1.4. Radio standards 41

Theoretical physics 42

Radio plasmas 43

Atomic frequency and time interval standards 44

Radio broadcast service 44

High-frequency electrical standards 45

Microwave circuit standards 47

Millimeter- wave research 48

Radio and microwave materials 48

Electronic calibration center 50

2.1.5. Heat 51

High-temperature thermocouple furnace 51

Photoelectric pyrometer 51

Specific heat of diamond at high temperatures 53

Thermodynamic properties of light-element compounds .... 53

Laboratory measurements of interstellar radio spectra 55

Low temperature thermometry 56

Acoustical interferometer 56

Resistance thermometers 56

Vapor pressure method 56

Pressure transducer for PVT measurements 56

Transport properties of air 57

International cooperative activities 58

Temperature symposium 58

2.1.6. Atomic physics 58

Laboratory astrophysics 58

Transition probabilities 58

Atomic energy levels 59

Collision cross sections 60

Standard wavelengths 60

Infrared spectroscopy of gases 60

Infrared spectroscopy of solids 61

Solid-state physics 61

Electron scattering 62

Atomic constants 63

Atomic standards of frequency 63

2.1.7. Radiation physics 64

Radioactivity standards 64

Radiation theory 64

Computer programs 64

Data collection 66

Civil-defense shielding problems 66

Linear electron accelerator 66

High energy radiation 67

X- and gamma-ray dosimetry 68

Photographic dosimetry 68

Chemical dosimetry 69

Irradiation facilities 69

Nucleonic instrumentation 69

Neutron physics ~0

Radiation protection and radiation standards and units .... 70

International standards 71

2.2. Chemistry and properties of materials 71

2.2.1. Analytical and inorganic chemistry 71

Applied analytical research 72

Chemical preparations 72

Spectrochemical advances 72

Separation of zirconium from hafnium 74

Distillation techniques improved 74

Accuracy for pH standards increased 74

A standard for blood pH 75

Standard hydrocarbon blends 75

Preparative scale chromatography 75

Round-robin purity determinations 75

Crystal chemistry 77

Coordination chemistry 77

Radiochemistry 77

2. Highlights of the research program— Continued

2.2. Chemistry and properties of materials — -Continued Page

2.2.2. Physical chemistry 77

Reactions of atoms at low temperature 78

Gas-solid reactions at high temperature 78

Light elements 78

Measuring isotope effects 79

Enolic acids 80

Molecular spectroscopy 80

Uranium standards 82

Isotopic abundance in silver checked 82

Photolysis of simple molecules 82

Radiolysis of simple hydrocarbons 82

Radical reactions formed by irradiation 83

Electron emission from surfaces 84

2.2.3. Mineral products 84

Crystal growth 84

Model defect structure 85

Vaporization data 86

Mechanical properties of ceramic bodies 87

Resonance techniques for determining elastic moduli . 88

Effects of roughness on the oxidation of iron 89

Standard X-ray diffraction patterns 89

Deuterium isotope effect in glass transformation 90

Ultra low-conductivity water 91

Index of refraction of liquids 91

2.2.4. Metallurgy 92

Vapor-phase crystallization studied 92

Oxidation processes studied 93

Nuclear magnetic resonance 93

Superconductor materials 93

Soft X-ray spectroscopy 94

Diffusion studies continued ' 95

Dislocations observed in metal foils 95

Phase diagram of quaternary system completed 95

Mechanical properties of 17-7 PH stainless steel investigated . 95

Properties of iron reviewed 96

Quantitative metallography obtained with digital computer. 97

Gases in metals 97

Gage blocks 97

Creep studies continued 97

Organic films increase fatigue strength 98

Metal polarization indicates corrosion rate 98

Stress corrosion 98

Heat effects of electrochemical processes 98

Research with molten salts 98

Mechanism of metal deposition studied 99

Electrodeposition from organic solutions 100

2.2.5. Organic and fibrous materials 100

New method for analyzing synthetic rubber 101

Model compounds used in vulcanization studies 102

Crosslinks determined in anisotropic fibers 102

Impact loading of fibers 102

Mechanism of retannage studied 102

Synthetic fibers structurally modified 102

Polymer crystallization studied 103

High pressure polymerization. 104

Thermal stability of polymers 104

Free radicals in polymers 105

Fungicidal analysis 105

Meteorite erosion of materials 105

Calcified tissues investigated 105

Dimensional changes in dentures 105

Dental amalgams from spherical particles 106

2.3. Special technical service programs 107

2.3.1. Applied mathematics 107

Combinatorial analysis 107

Eigenvalue theory 108

Matrix theorv 108

Highlights of the research program — Continued

2.3. Special technical service programs — Continued

2.3.1. Applied mathematics — Continued Page

Approximation theory 108

Numerical experimentation 108

Machine translation 108

Mathematical tables 109

Digital computation 109

Experiment designs 109

Life testing and reliability 110

Probability and mathematical statistics. . . 110

Mathematical physics 110

Operations research Ill

2.3.2. Data processing systems Ill

PILOT data processor 112

Technical assistance for data processing 112

Components and techniques 113

Automatic data retrieval 114

Development of information selector 114

Special purpose digital computer (AMOS IV) 114

Data source automation 115

Weapons systems evaluation 115

Airways systems analysis 116

Pictorial data processing 116

Psychological data processing 116

Data processing applications 116

Research information center 118

Developments in automatic mail sorting 118

Mechanization of patent searching 118

Simulation of traffic flow 119

2.3.3. Instrumentation 119

Meteorological instrumentation 120

Antarctica assistance 121

Hygrometry 121

FOSDIC 121

Telemetering pickups 121

Electronic fault location 122

Electron emission of thermionic cathodes 122

Vapor pressure of alloys 123

Instrumentation reference service 123

Technical communication 123

2.3.4. Radio propagation 123

Ionosphere research and propagation 124

VLF phase stability studies 125

Magnetic field micropulsations and electron bremsstrah-

lung 125

Ray tracing through the real ionosphere 125

Doppler fading studies 126

First rocket-borne soundings of the topside of the iono-
sphere 127

Studies of the interplanetary medium 127

Radio reflections from artificial electron clouds 128

Radio propagation engineering 128

Tropospheric transmission loss predictions 128

Wideband data transmission 128

Mutual interference between surface and satellite com-
munication systems 129

Technical factors influencing allocations 130

Signal characteristics of mountain obstacle paths 130

Refraction effects in microwave tracking systems 130

Radio meteorological sensors 132

Atmospheric refractivity models 132

Automatic amplitude distribution analyzer 132

Engineering standards for tropospheric communication. 133

Prediction of radio noise from thunderstorm counts. . . . 133

Radio systems 133

Low and very low frequency systems (30-300 kc/s) .... 134

High frequency systems 134

Very high frequency systems 136

2. Highlights of the research program — Continued

2.3. Special technical service programs — Continued
2.3.4. Radio propagation — Continued

Radio systems — Continued Page

Antenna research 136

Modulation research 137

Navigation and timing systems 138

Upper atmosphere and space physics 139

Preliminary measurements of electron densities to 1200

k'lometers 140

Radiation produced from a plasma 140

Investigations in particle processes 140

Cosmic noise study at USSR Mirny Base, Antarctica. . . 140
Satellite radio signals used to study structure of iono-
sphere 141

Meteor burst propagation observations successful 141

Observatory installed at Maui, Hawaii 141

Numerical representation of the ionosphere 142

IGY world data center A 142

2.3.5. Cryogenic engineering 143

Superconducting electromagnets 143

Properties of para-hydrogen 143

Cryogenic materials data handbook 144

Practical thermometry 144

Two-phase fluid phenomena 145

Heat transfer 145

Cryogenic equipment and instrumentation 146

Magnet research 146

Low temperature seals 146

Refrigeration processes 146

Consultation and advisory services 147

Cryogenic engineering data 147

Gas liquefaction 148

2.3.6. Building research 148

Air void systems in hardened concrete 150

Creep and shrinkage of structural lightweight concretes. ... 150
Characterization of cement compounds by infrared spectros-
copy 150

Crack propagation and the fracture of concrete 150

Calcium aluminate complex salts 150

Extinguishment of fires 151

Flammability of materials 151

Heat pump studies 151

Field studies of air-to-air heat pumps 151

Water vapor permeance of building materials 152

Underground jaeat distribution systems 153

Moisture in flat insulated roof constructions 153

Standards for refrigerated vehicles 154

Design loads for plumbing systems 154

Advances in thermal conductivity measurements 154

Organic coatings manual 155

Safety codes 155

Symposium on Chemistry of Cement 155

2.3.7. Weights and Measures 156

3. Appendixes 159

3.1. Organization . 159

3.2. Summary of NBS staff 165

3.3. Financial data on NBS program 165

3.4. Advisory committees 167

3.5. Awards and honors 172

3.6. Education and training program 173

3.7. Cooperative research with industry 175

3.8. List of publications and patents 176

Vll

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1. GENERAL REVIEW

On March 3, 1961, the National Bureau of Standards completed 60 years
of service to science, industry, and commerce. Throughout this period it
has been concerned with precision physical measurement, with the pro-
motion of reliable and uniform measurement in the United States, and with
a wide variety of research activities.

For measurements to have general meaning and validity, they must be
based on common units and standards that are precisely and reliably known.
Only then can there be effective interchange of information among scientists,
realistic utilization of scientific data by engineers and technologists, orderly
exchange of goods in commerce, and realization of the concept of inter-
changeable parts throughout industry. It is the Bureau's responsibility to
develop and maintain the national standards upon which all measurements in
this country are based, and to see that these standards are made available
to science and industry through suitable calibration services.

A second important responsibility of the Bureau is to provide reliable
and precise data on the basic properties of matter and materials that are of
importance to science and industry. As such data are obtained by precise
measurement, the performance of this function both draws upon and at the
same time increases the Bureau's background of knowledge and competence
in the field of measurement.

Through a broad program of research in the physical sciences, the Bureau
continually strives to keep abreast of the measurement requirements of
American science and technology. To insure that measurement inadequacies
do not retard progress, it must anticipate tomorrow's measurement problems
and lead in their solution, developing new standards and measurement
techniques as new fields open up or become more active.

Such a research program provides a broad basis for service to the Govern-
ment and the Nation in a variety of other ways. These include the develop-
ment of test methods for materials, cooperation in the establishment of codes
and specifications, and advisory services to other Government agencies on
technical problems.

A third major NBS responsibility is the operation of central research and
technical service programs for the Federal Government. Included in this
category are the Central Radio Propagation Laboratory, the Data Processing
Systems Laboratory, the Building Research Division, the National Hydraulics
Laboratory and the Cryogenic Engineering Laboratory.

This report attempts to present the highlights of the Bureau's program
for the fiscal year 1961. In section 2, the body of the report, representative
studies and achievements from the various fields in which the Bureau is active

have been selected for brief presentation. However, the breadth of the pro-
gram and the diversity of projects may make it difficult for the reader to
obtain a coherent picture of the year's activity. The remainder of section 1
is therefore devoted to a brief summary of the more important accomplish-
ments and activities of the year.

Progress in Measurement Standards

To provide a basis for accurate electrical measurements, the Bureau
maintains very precise standards of electrical resistance and voltage from
which all other electrical and electronic standards are derived. The values
assigned to these two basic electrical standards are calculated from extremely
precise measurements made in terms of the basic units of length, mass, and
time. Such measurements, which must be periodically repeated, serve to
fix the relation between the electrical and mechanical units so that they may
be used together with consistent results.

During the year, the NBS unit of resistance was redetermined by a new,
more accurate method. The determination made use of a capacitor whose
value can be calculated to a high degree of accuracy from its dimensions.
The NBS unit of resistance was then evaluated by comparison with this
capacitor. The value obtained was self-consistent to better than a part in
a million and was within approximately two parts per million of the value of
the ohm as maintained by NBS on the basis of earlier measurement techniques.

A basic problem in electrical standardizing laboratories has been to
translate direct-current measurements, which are closely related to the funda-
mental standards, into alternating-current measurements at the frequencies
used in electrical power generation and in radio and electronics work. A
recent contribution to the solution of this problem was the development of a
"differential thermocouple voltmeter" which indicates directly the percentage
difference between an unknown alternating voltage and a previously stand-
ardized voltage.

The Bureau's atomic standard of frequency, which is now maintained by
means of a natural frequency of the cesium atom, was operated on a regular
basis throughout the year and was used to monitor the NBS standard fre-
quency broadcasts. International comparisons showed continued agreement
between this standard and the atomic frequency standards of Switzerland and
the United Kingdom to 1 or 2 parts in 10 billion. The high stability of atomic
frequency standards led to active consideration, on the international level,
of specific plans for a redefinition of the second in terms of an atomic
frequency.

To disseminate the frequency standard more effectively, the Bureau is
working toward the construction of a standard frequency broadcast station
to be located near Fort Collins, Colo. The new station will transmit fre-
quencies of 20 and 60 kilocycles. Because these lower frequencies are trans-
mitted directly along the surface of the earth rather than by reflection from
the ionosphere, the received signals are much more stable. This permits

their transmission over great distances with greater accuracy than the short-
wave broadcasts of NBS stations WWV and WWVH. The new station will
have a much higher radiated power than the Bureau's existing low-frequency
stations near Boulder, Colo.

Intensive research programs were continued to develop standards and
measurement techniques for very high temperatures and pressures. Reliable
temperature measurements were made by spectroscopic techniques in the
vicinity of 16,000 °C, and extremely compact equipment recently developed
for generating pressures in excess of 1 million pounds per square inch was
further refined. Pressures reached in an experiment with this equipment can
now be predicted within a few percent, as compared with 20 percent a year
ago.

In recent years there has been great scientific interest in research at ex-
tremely low temperatures, within a few degrees or less of absolute zero. In
this temperature region the molecules of which matter is composed become
less active in their constant motion, so that much can be learned about the
ultimate nature of matter.

As the success of physical research at the low temperatures depends to
a great extent upon the accuracy with which temperatures can be measured
in this region, the Bureau has been conducting an active program to provide
a temperature scale and thermometer calibration service in the range from
1.5 to 20 °K ( — 457 to —423 °F) . In 1961 an acoustical interferometer was
constructed and used successfully to measure very low absolute temperatures
in the liquid helium range. Further development of this instrument, which
makes use of the change in the velocity of sound in helium gas with tempera-
ture, is continuing. Favorable results were also obtained in investigations
of carbon and germanium resistors for use as precision secondary
thermometers in the liquid helium temperature region.

Reliable precision measurement techniques and standards for neutrons
are urgently needed both in the power reactor field and in various areas
of basic and applied research, such as the study of radiation effects and the
development of health physics instrumentation. Although the Bureau has
developed a low-intensity neutron standard, it has lacked facilities for measur-
ing the high-intensity fluxes that occur in a nuclear reactor. At the close of
the year design work was nearly complete for a high-flux research reactor
to be constructed at the Bureau's new site at Gaithersburg, Md. The reactor,
to be known as the NBSR, will enable the Bureau to fill its growing responsi-
bilities in the many rapidly expanding fields of atomic energy. The reactor
will advance the measurement and understanding of the effects of radiation
on substances of all kinds, and will provide a powerful tool for analysis of
atomic and molecular structure. Of particular importance among the basic
processes to be studied is that of fission. Inadequate understanding of this
process still limits the design of fissile material breeding plants.

The value of a uranium reactor fuel depends on the abundance of the
uranium-235 isotope and accurate standards of composition are required to
make precise mass spectrometric determinations of this abundance. During

the past year, a special mass spectrometer was developed for analyzing
uranium hexafluoride; it is being used to evaluate standards having low
concentrations of uranium 235. This instrument has also been used to
compare the natural abundances of uranium in samples from different
geographical areas.

In the past several years, measurements of very low levels of radio-
activity have become more numerous and exacting in such fields as
archeological dating, biological and medical studies, and health physics.
Because of this increased activity, a thorough investigation into the radio-
active contamination of materials used in radiation detection has become
necessary, and a demand for radioactivity standards at very low concentra-
tions has arisen. To meet this need, a new laboratory facility for the measure-
ment of very low levels of radioactivity — down to a millionth of a curie — was
constructed. This facility is being used to study methods of measuring the
amounts of radionuclides present at very low concentrations and in making
international comparisons of radioactive samples at these concentrations. It
will also be used to prepare accurate radionuclide standards for a number of
scientific and industrial applications.

Other work on radioactivity standards resulted in the development of
a manganese-54 point source standard, a scandium-46 gamma-ray standard,
an iron-55 electron-capturing nuclide standard, and a promethium-147 beta-
ray standard. In addition, a more accurate value for the half-life of carbon
14 — important in geological and archeological dating — was obtained. The
new value is 5,760 years with an overall probable error of 1 percent, and is
about 4 percent greater than the previously accepted value of 5,568 years.

Measurements of the acidity or basicity of solutions, expressed on the
pH scale, are of critical importance not only in chemical analysis and medical
research but in the control of many industrial processes. Some years ago
the Bureau took the lead in establishing a standard pH scale that would meet
the needs of both science and industry. Standards for the adjustment of pH-
measuring equipment to conform to this scale have been issued by NBS for
more than 15 years. However, fundamental difficulties in the calculation of
a standard pH have made it necessary to limit the accuracy in the assignment
of pH values to ±0.01 unit. Within the past year a mutually satisfactory
convention was developed in cooperation with the pH committee of the British
Standards Institution, and the third decimal place is now being assigned to
pH standard values.

In response to many requests, a new standard was established especially
for the measurement of the pH of blood and physiological media. Accurate
measurements of the pH of blood are of great importance both in medical
research and in the diagnosis of pathological conditions. However, the
changes in pH that must be detected are very small. To increase the accuracy
with which these measurements can be made, the new standard was required
to have, at body temperature, about the same pH as blood. It was prepared
from pH standard materials already issued by the Bureau.

Studies of Matter and Materials

Water, because of its abundance, its importance to the physical sciences,
and its role as a life-supporting liquid, has been the subject of intense study
for many years. Recently, by applying an electrophoretic ion-exclusion
technique, the Bureau succeeded in preparing water of extremely low ion
content. This water has an electrical conductivity of 0.039 X 10~6 ohm-1 at
18 °C, indicating a residual ion content which is equivalent to a sodium
chloride concentration of one part per billion. Containing less than one-
third of the ionic impurities of the water prepared by Kohlrausch and Hey-
dweiller in their historic purification experiments, this water approaches the
theoretical conductivity — and ideal purity — more closely than any previously
reported.

In 1960 Bureau scientists found that ethane molecules lose molecular
hydrogen when subjected to ultraviolet light of very short wavelength. Dur-
ing the past year additional studies were made of the effect of radiation on
other simple molecules. Ethylene was found to decompose by a similar
process, and further experiments with ethylene showed that molecular detach-
ment of hydrogen also occurs under the action of gamma rays. Such
experiments give valuable insight into the detailed processes induced by
high-energy radiation and provide information on the origin of radiation
damage to materials. The formation of molecular hydrogen by action of
ultraviolet radiation on water vapor was also observed; this process may
account for the presence of hydrogen molecules in the upper atmosphere.

Detailed investigations of the structures of several important molecules
were carried out by spectroscopic studies in the ultraviolet, visible, infrared,
and microwave regions of the spectrum. Through the use of microwave
techniques, it was possible to measure interatomic distances with very high
accuracy in a variety of hydrocarbons and their simple derivatives. Small
variations were detected in the lengths of the bonds between carbon atoms
in these molecules, and these changes shed some light on the nature of the
chemical bonds. The microwave studies also provided other molecular
information, such as electric dipole moments and quadrupole coupling con-
stants, which can be correlated with the geometric structure of the molecules.

High magnetic fields have important uses as deflectors of charged particles
in the particle accelerators and detection devices of nuclear physics, in nu-
clear power converters, and for plasma containment in fusion reactors. If
the magnet is cooled to low temperatures so as to greatly reduce its elec-
trical resistance, a considerable amount of power that would otherwise be
lost as heat becomes available for producing a higher magnetic field. To
take advantage of this principle, a high-purity aluminum foil magnet with
liquid hydrogen cooling for low-temperature operation was recently designed
and is nearing completion. Using only 4 kilowatts of power, it is designed
to produce a magnetic field of 100,000 gauss in a cylindrical volume 3 inches
in diameter by 8 inches long.

At very low temperatures some metals such as lead and tin become super-
conductors, that is, they completely lose their electrical resistance. Obvi-
ously a superconducting electromagnet would provide a very effective means
of obtaining extremely high magnetic fields. Until recently, however, such
a superconducting magnet was not regarded as practical because most super-
conductors are driven into the normal, conducting state by rather small
magnetic fields. Within the past year several alloys or compounds have
been discovered that remain superconducting in the presence of high mag-
netic fields and while carrying large currents. One of these, a niobium-tin
compound (Nb3Sn) clad in niobium, has been investigated by the Bureau,
with the support of the Atomic Energy Commission, in fields up to 190,000
gauss. The results indicate that this material can be used to make solenoidal
magnets that will produce magnetic fields of well over 100,000 gauss if oper-
ated from 1 to 4 degrees above absolute zero.

Astrophysical and Plasma Physics Research

In recent years there has been great scientific interest in the nature and
physical behavior of extremely hot gases such as occur in thermonuclear
devices and in outer space. Yet this field of physics is still very poorly
understood. As a result of this lack of knowledge, progress is being held up
in a number of important branches of science and technology — among them
space exploration and astronomy, thermonuclear power and plasma physics,
ultra high temperature research, atmospheric research, and ballistic missile
defense systems.

In this situation the major problem is a lack of precise measurement
techniques, standards, and basic data on the fundamental properties of the
hot gas or plasma. Many of the laboratories attempting to apply plasma
physics to practical objectives are thus forced to rely on costly and in-
efficient empirical methods. To help solve this problem, the Bureau in 1960
began a special effort to unify and strengthen its work in plasma physics
and astrophysics. This work is now being carefully coordinated to develop
the necessary measurement standards, basic data, theoretical guidance, and
interpretative techniques for determining the relevant properties of hot gases
and for the solution of important problems in modern astrophysics.

The most immediate need for such knowledge and services arises in the
space sciences, where satellites are used to carry equipment outside of the
earth's atmosphere to study the sun and the stars. The value of the spectro-
scopic data thus obtained can be greatly enhanced if they can be accurately
described in measurement units based on precise laboratory standards. The
Bureau is making accurate measurements of atomic properties to provide the
data necessary for quantitative interpretation of these astronomical obser-
vations.

To study the probabilities of atomic transitions associated with hydrogen
and oxygen lines observed in solar and stellar spectra, the Bureau developed
a wall-stabilized high-current arc chamber operating in hydrogen at 12.000

A high-current arc chamber operating in hydrogen at 12,000 °K, a tempera-
lure twice that of the sun. The arc is used in research on the fundamental
properties of extremely hot gases such as occur in thermonuclear processes and
outer space. Lack of precise measurement techniques, standards, and basic
data on the fundamental properties of plasmas is a major problem in the space
sciences (page 6).

°K, a temperature twice that of the sun. A characteristic red light emitted
by the hydrogen through slits in the arc chamber is photoelectrically re-
corded with a spectrometer and provides information to determine tempera-
ture and particle concentrations within the plasma.

A tabulation of the relative intensities of 39,000 spectral lines was com-
pleted during the year, providing intensity values on a uniform energy scale
for 70 elements over the wavelength range from 2000 to 9000 Angstrom units.
The new tables will supply much-needed quantitative intensity values for those
elements most commonly encountered in spectrochemical analysis. The
intensity values may be transformed into atomic transition probabilities
and used to determine temperatures of laboratory light sources emitting
atomic spectra and of stellar atmospheres.

In addition to the data center on atomic transition probabilities which was
set up last year, a data center on atomic collision cross sections was established
to gather and index all published information in this field. A complete file of
scientific papers on low-energy electron cross sections has been collected, and
about one-half of the papers have been coded on punched cards. Plans call
for extending the data collection to other atomic cross sections as soon as is
feasible.

Through the production of radio waves from plasmas in the laboratory, a
major step was taken toward duplicating under controlled conditions the
electromagnetic processes which occur in the upper atmosphere. Plasmas
were produced in helium by a high-velocity shockwave travelling over 100
times the speed of sound. When the plasmas were studied in the presence of
a transverse magnetic field, radio waves resulting from interaction between
the shockwave and the magnetic field were observed. A high-speed camera,
capable of operating at over 100 million frames per second, was devised to
study the luminous phenomena in the Shockwaves.

Radio Propagation Research

The NBS Central Radio Propagation Laboratory (CRPL) has the primary
responsibility within the Federal Government for collecting and disseminating
information on radio wave propagation. The results of its research program
are of value to radio and television broadcasters, the military services, space
scientists, and operators of many types of communication systems.

A large part of CRPL research deals with the properties of the series of
electrically charged layers in the upper atmosphere known collectively as the
ionosphere. Through their ability to reflect radio waves, these layers play
an important part in long-distance radio communication.

By analyzing radio signals received from satellites, CRPL has been able
to study the structure of the upper part of the ionosphere, measuring the
density of electrons and other characteristics. Current studies are investi-
gating the size, shape, and motion of various ionospheric irregularities as
observed at a number of stations. The results obtained in this work should
aid communication with space vehicles since radio signals from space are
seriously affected by irregularities in the electron density of the ionosphere.

On June 24, 1961 the first rocket-borne soundings of the topside of the
ionosphere were made by means of a four-stage rocket carried to an altitude
of over 600 miles. Successful radio pulse reflections from the topside of the
ionosphere were obtained for about 13 of the 14 minutes that the payload
was above the ionosphere.

The rocket, a Javelin, was launched from the National Aeronautics and
Space Administration's Wallops Island (Va.) facility. The purpose of the
experiment was to test the sounding system that is to be used in a topside
sounding satellite to be placed in orbit at a later date. Such a satellite will
be of great value in advancing man's knowledge of the ionosphere. NBS
responsibilities in this program include overall planning, design and per-
formance of the experiment, and analysis of the resulting data. Airborne
Instruments Laboratory, a division of Cutler-Hammer, Inc., is designing and
building the rocket and satellite payloads and the ground data-handling
equipment. Technical management and sponsorship is by the NASA
Goddard Space Flight Center.

Data Processing Systems

The Bureau continued to serve the Government as a central research and
development agency in automatic data processing and as a readily available
information center for the solution of specific problems in this field. During
1961 services to other Federal agencies included assistance to the Bureau of
Naval Weapons on problems of weapons-systems evaluation and test-range
instrumentation of the Pacific Missile Range; studies of a future air-traffic
control system for the Federation Aviation Agency; research for the Navy
on computer methods for translating aerial photographic information into
elevation profiles; and development of a program for simulating municipal
traffic flow by high-speed automatic data-processing equipment for the
Bureau of Public Roads.

In studies of computer components, significant advances were made in the
theoretical analysis of solid-state semiconductor devices operating as circuit
elements. For example, a large-signal equivalent circuit, valid for all modes
of circuit operation, was produced for junction transistors. Equations were
developed that make possible the analytic solution of modes of junction-
transistor operation previously considered untractable.

Calibration, Testing, and Standard Samples

The Bureau continued to be faced with the demands of a rapidly expand-
ing technology for calibration services to insure accuracy in laboratory, shop,
and plant, and to meet the need of state and local weights and measures
enforcement officers. In meeting these critical needs it was aided by the
extensive calibration programs that are being established in the military
agencies and in many industries and private standards laboratories. The
Bureau continued, insofar as possible, to restrict its calibration work to master
standards and high-precision instruments, leaving the calibration of lower-
echelon standards to the other standards laboratories that have been set up.
To an increasing extent, the Bureau was called upon for assistance to these
laboratories.

The activity of the Aerospace Industries Association, in surveying the
measurement needs of its member firms, has proved very useful and infor-
mative to the Bureau in planning and developing calibration services. In
1959, the Association questioned 70 companies in its field and found greatly
increased measurement needs in several critical areas such as microwave,
temperature, vibration, and shock measurements. Over 100 of these needs
were for measurement and calibration services not then offered by NBS.
Either the Bureau did not provide any service for the particular physical
quantity involved, or the range of measurement or accuracy required was
not available. This survey clearly showed the immediate need for more
basic research on measurement problems and increased industry-wide dis-
semination of calibration procedures.

616114 O— 61-

As a followup to the AIA Industry Calibration Survey, a series of 16
meetings between measurement specialists from AIA member firms and
NBS technical staff members was held at the Bureau over the past 14 months.
Aimed at bringing into sharp focus the impact of the "measurement pinch"
as it affects the aeronautical and missile industries, these conferences dealt
with the following subjects: Temperature; infrared radiation; humidity;
vacuum and flow; force and acceleration; shock and vibration; internal
diameters; surface flatness and finish; gear calibration and measurement;
pulsed voltage; radiofrequency impedance and phase; radiofrequency power,
current, and impedance; radiofrequency voltage and field strength; micro-
wave power; microwave attenuation; microwave VSWR, impedance, and
phase. The conferences identified many specific areas in which the air-
craft and space industries face severe measurement problems. For example,
an industry representative cited a million-dollar development of radomes
which had to proceed more by trial and error than by test and analysis,
because precise phase and amplitude measurement capabilities do not exist
in the required frequency range. As a result of the meetings, the Bureau's
planning in all the measuremer<t areas that were covered has benefited, and
steps have been taken to immediately place greater emphasis on calibrations
and related work in the most critical areas such as microwave power and
attenuation, high temperature, infrared radiation, and engineering metrology.

To facilitate liaison with those who use the Bureau's services, a new Techni-
cal Advisory Committee on Calibration and Measurement Services was es-
tablished. The committee includes leaders in specialized fields drawn from
industry, and will foster NBS-industry cooperation in precision measurement.
It will advise the Bureau concerning current and anticipated needs of industry
for measurement and calibration services, indicating the extent and relative
urgency of these needs and suggesting how the Bureau's skills and resources
may best be utilized toward meeting them.

The Bureau has also been working closely with the Department of Defense
and its contractors to keep informed of new measurement problems and
calibration needs. During 1961 a series of visits to the plants of Air Force
contractors was made by a Joint NBS-U.S. Air Force Working Group on
Standards. It was found that significant progress has been made in measure-
ment standards activities over the past few years and in most plants a keen
awareness of the need for highly accurate standards of physical measurement
has developed. At the suggestion of several defense agencies, the Bureau's
Electronic Calibration Center held a 5-day workshop on microwave frequency
measurements for technical supervisors from standards laboratories in the
Department of Defense.

The greatly increased activity in measurement standards throughout the
country was indicated by proposals from various sources for the establish-
ment of associations to deal with technical and administrative problems of
the industrial standards laboratories that are being set up to serve as inter-
mediaries in the calibration chain between NBS and industrial plants.

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During the year the Bureau participated in several meetings initiated by rep-
resentatives of industrial standards laboratories to determine the need for
and possible role of an association of standards laboratories.

A three-volume Handbook entitled Precision Measurement and Calibra-
tion was issued to provide a "textbook" and reference source for the many
scientists and engineers who must be trained in the shortest possible time to
fill responsible positions within the new standards laboratories. This 2800-
page Handbook is a compilation of technical papers on measurement and
calibration by the NBS staff. The three volumes, extensive as they are,
include only a fraction of the Bureau's work relating to measurement; how-
ever, supplementary references are listed and many of the reprinted papers
include bibliographies in this field.

An important medium for the exchange of information on electronic meas-
urements was the Conference on Standards and Electronic Measurements,
during the summer of 1960, at the Boulder Laboratories. Sponsored jointly
by the American Institute of Electrical Engineers, the Institute of Radio
Engineers, and NBS, the three-day meeting was attended by more than 800
scientists and engineers from industry, universities, and Government. The
Bureau also cooperated with the American Institute of Physics and the
Instrument Society of America in sponsoring a Symposium on Temperature —
Its Measurement and Control in Science and Industry, held in Columbus,
Ohio, March 27-31. More than 250 papers were presented at this Sympo-
sium, the fourth in a series begun in 1919.

The nature and scope of the activity in calibration and testing are shown
for fiscal year 1961 in tables 1 and 2. A total of 129,540 calibrations and
tests were performed for Government and industry.

Closely related to the calibration effort is the standard materials program
(table 3). During the past year the Bureau distributed 78,148 samples of
standard materials to other laboratories for use in controlling chemical
processes and in maintaining the accuracy of apparatus and equipment.
Over 600 different standard materials are at present available — principally
chemicals, ceramics, metals, ores, and radioactive nuclides. All are certified
either for chemical composition or with respect to a specific physical or
chemical property such as melting point, viscosity, color, or index of
refraction.

Cooperative Activities

The Bureau cooperates extensively with Federal, State, and local govern-
ments; with national professional societies and standardizing bodies; and
with many international groups. In this way the results of Bureau research
are brought to bear on many current problems of science and industry,
particularly those relating to measurement standards, building and safety
codes, engineering and purchase specifications, and test methods.

Cooperation with other Federal agencies ranges from the supplying of
technical information upon request to long-range projects undertaken through

various scientific and technical committees. An important example of inter-
agency cooperation is the development of Government specifications and test
methods. During the year at the request of the General Services Adminis-
tration, the Bureau accepted responsibility for developing and maintain-
ing 7 additional Federal Specifications, making a total of 157 for which it
now has this responsibility. The Bureau also reviewed approximately 400
proposed specifications both for GSA and for other agencies to determine
their suitability for use by the Federal Government.

Cooperation with State and municipal governments is principally in the
field of weights and measures. Although the Bureau itself does not have
regulatory powers, it offers technical advice and consultation to local regula-
tory bodies and it calibrates and adjusts State standards of weights and
measures. A major medium of cooperation is the National Conference on
Weights and Measures. Thirty-five States, the District of Columbia, Puerto
Rico, Canada, and the United Kingdom were officially represented at the
46th annual meeting of this Conference, held in Washington, D.C., June 12-
16, under NBS sponsorship.

Through the participation of Bureau staff members in the work of national
professional societies and standardizing bodies, the Bureau plays an active
role in the development of test methods and criteria, in the application of
scientific discoveries, and in fundamental research programs of national
scope. During the past year Bureau staff members held 1,250 committee
memberships in 150 national groups such as the American Society for Testing
Materials, the American Standards Association, American Society of Me-
chanical Engineers, American Chemical Society, Institute of Radio Engineers,
and Instrument Society of America.

In many of these groups NBS staff members work with industry to provide
codes and specifications, standard test methods, and standard data on the
properties of engineering materials. To help the Bureau cooperate with
industry in these areas, a new Technical Advisory Committee on Engi-
neering and Related Standards was established. This Committee will be
concerned with national needs in the general field of standard practices and
will seek to maintain awareness of the efforts of private organizations in this
field, fostering cooperative programs and recommending use of the Bu-
reau's special competence where needed.

Other means of Bureau-industry cooperation include the Research Asso-
ciate Plan and the donor program. Under the Research Associate Plan,
technical, industrial, and commercial organizations can support work at
the Bureau that is of special interest to them, yet of sufficient general interest
to justify use of Government facilities. The work is done by research asso-
ciates who are paid by the sponsor but otherwise function as members of
the Bureau staff. At the present time 11 groups are supporting research
associates at the Bureau (appendix, p. 175) .

The donor program was authorized in 1950 by Public Law 619 under which
the Bureau may accept funds for the purpose of furthering its work. This

arrangement permits individuals as well as technical, industrial, and com-
mercial organizations to support work at the Bureau when the results are
expected to be of value to the general public. During the past year, eight
projects were supported by gifts from six organizations (p. 175).

On an international basis, the Bureau represents the interest of the Gov-
ernment and American science in matters dealing with the establishment and
maintenance of standards and establishment of values for scientific constants.
Most of this work is done through participation in a large number of inter-
national groups such as the International Union of Pure and Applied Chem-
istry, International Scientific Radio Union, International Commission on
Illumination, and International Organization for Standardization. Approxi-
mately 124 staff members attended meetings of international societies during
the fiscal year.

In October 1960 the Director of the National Bureau of Standards and
the Chief of the NBS Metrology Division attended the 11th General Con-
ference on Weights and Measures, in Paris, as head and member, respec-
tively, of the American delegation. An outstanding accomplishment of this
Conference was the adoption of a new international standard of length — a
wavelength of light — replacing the meter bar which had served as the standard
for over 70 years. The meter was thus defined as 1,650,763.73 wavelengths
of the orange-red line of the isotope krypton 86. Other actions taken by
the Conference included the establishment of a central facility at the Inter-
national Bureau of Weights and Measures for international coordination of
radiation measurements, confirmation of a new definition of the second of
time in terms of the tropical year 1900, and adoption of refinements in the
scales for temperature measurements.

In April 1961 the National Bureau of Standards was represented at the
Pan American Standards Committee Meeting in Montevideo, Uruguay, by an
Associate Director and a Consultant to the Director. These staff members
also visited several other South American countries to confer with representa-
tives of Government and industry regarding the development and promotion
of standards for Latin American raw materials and semi-manufactured prod-
ucts, to discuss exchange of personnel between NBS and Latin American
standards laboratories, and to inquire into the effect on commerce and trade
of the disparity between the English units of measurement used in the
United States and the metric system employed in Latin American countries.
Another aspect of international cooperation involves a program whereby
scientists or diplomatic representatives from other countries are accepted
at the Bureau as guest workers or visitors. Approximately 1.100 foreign
scientists and technicians, representing 61 countries, visited the Bureau
during the year. Forty-five of these visitors were specialists who came as
guest workers to spend from 1 to 12 months in cooperative research. Twenty
were trainees who were being prepared for leadership in the national
laboratories of their own countries.

Administrative Activities

A number of administrative changes were made as part of the Bureau's
efforts to meet the expanding needs of modern science and technology. The
divisional reorganization which began in 1960 was completed in 1961 with
the subdivision of the former Chemistry Division into two more cohesive
divisions: Analytical and Inorganic Chemistry, and Physical Chemistry. In
another change, the technical Associate Directors were relieved of responsi-
bility for supervision of particular divisions so that they could spend full
time in staff work for the Director and Deputy Director. (See appendix, p.
159, for revised organization.) Also, advisory committees of outside ex-
perts were set up in the areas of calibration and measurement services
(p. 171 ) , and engineering and related standards (p. 171 ) .

In addition to the existing technical advisory panels appointed by the
National Academy of Sciences-National Research Council (appendix 3.4),
a special NAS-NRC study was initiated on the Bureau's building research
program. The study implements a recommendation of the 1960 report to
the Secretary of Commerce by NAS-NRC on the role of the Department in
science and technology.

On June 14, Secretary of Commerce Luther H. Hodges broke ground for
a new Engineering Mechanics Laboratory. This laboratory is included,
along with the power plant and initial site development work, in the first
construction contract let for the Bureau's new research center at Gaithers-
burg, Md. At the Boulder Laboratories construction of a sixth wing for the
main laboratory building was well under way.

At the end of the year, the total staff was about 3,900 persons, slightly
less than one-third of them at the Boulder Laboratories. Appendix 3.2
gives further data on staffing.

Two new types of positions were established during the year: Senior
Research Fellow and Senior Visiting Scientist. Their purpose is to afford
recognition to distinguished scientists and to enable them to do independent
research and consultation of a broad character beyond the scope of a
particular division.

Funds obligated during the year totaled $52,244,000 including $13,406,000
for facilities. Of the $32,812,000 total for the research and development
effort, $19,578,000 came from the direct appropriation for Research and Tech-
nical Services and $13,234,000 from other agencies and private sources. In
addition, calibration, testing, and other services totaled $6,026,000. A more
complete presentation of financial data is contained in appendix 3.3.

One of the groups interested in the Bureau's future capabilities is the
House Committee on Space and Astronautics. After hearings with Bureau
officials, the Committee published a report (House Report No. 711, 87th
Congress, 1st Session) which included the following:

"The Bureau of Standards provides a number of services to industry and commerce,
to the scientific community generally, and to Federal agencies. ... its range of interest
has, perhaps, a wider scope than that of any other Federal research institution.

"The programs of the Bureau are a large contribution to the work of scientists and
engineers of the country. They provide a technical foundation for space, military, and
atomic energy programs. Technology and research and development in technological
fields play an ever increasingly important part in the life of today. Dr. A. V. Astin,
Director of the National Bureau of Standards, sums up this situation as follows:

'By almost any measure, the growth of science and technology in this century
has been phenomenal. Regardless of whether we look at the rapidly increas-
ing number of scientists, the greatly increased amounts of funds applied to
research and development, the staggering growth in the volume of technical
literature, or the tremendous multiplication of new devices and materials from
our industrial machines, we find a rate of expansion very much in excess of
the rate at which the general population is increasing.

'For some time the rate of growth of the U.S. population has been doubling
about every 50 years whereas the number of scientists in several of the major
disciplines has been doubling about every 10 years. Comparable exponential
growth rates are found with other indices of scientific progress.' "

In light of the growth picture, efforts were continued and extended to
determine present and future needs for standards of measurement and associ-
ated calibration services. Within the Bureau a more systematic procedure
was adopted for evaluation of current programs. Also, program planning
began to be projected further into the future as part of the Government- wide
effort to develop tentative budget estimates for at least five years in advance.

Publications

Publications are a major end product of the Bureau's research effort.
They are the principal means by which the results of NBS projects are made
available to science and technology. The publications of the Bureau are
therefore suggestive of the scope and level of its technical program. During
the year these totaled 937 formally published papers and documents. In
addition some 390 classified and unclassified reports were issued to other
Government agencies.

A major publication of the year was Precision Measurement and Calibra-
tion (Handbook 77). This three volume Handbook (p. 14) is a compila-
tion of the more important NBS publications of recent years dealing with
precision measurement and the calibration of standards.

Another three-volume reference work was completed with the publication
of part III of Screw Thread Standards for Federal Services (Handbook 28) .
This Handbook represents the work of the Interdepartmental Screw Thread
Committee, which is sponsored by the Departments of Defense, Army, Navy,
Air Force, and Commerce to promote uniformity in screw-thread standards
in the Departments concerned.

Other significant reference works were X-ray Protection Up to Three
Million Volts (Handbook 76), which gives National Committee on Radia-
tion Protection and Measurements recommended safety standards in this
field; and Bibliography of Temperature Measurement (Monograph 27 1
which contains more than 500 references published between January 1953
and June 1960 in the field of temperature measurement.

:"<..*:'

Secretary of Commerce Luther H. Hodges formally breaks ground for the con-
struction of the new NBS laboratories at Gaithersburg, Maryland. The Bureau
expects to be relocated in its new campus by 1964. On the speakers' platform
behind the Secretary are Dr. A. V. Astin (left), NBS Director, and John L.
Moore, Administrator of the General Services Administration (page 17).

Unique among the year's publications was The Metric System of Measure-
ment (Miscellaneous Publication 232), a 46- by 29-inch wall chart for
classroom use. An updated version of an all-time favorite visual aid, this
new metric chart includes the recent redefinition of the meter in terms of
a wavelength of light. The chart shows the interrelationships among the
units of the International Metric System of measurement, and the relation-
ships between the metric units and the units of the English system.

Of the 937 formal publications issued during the year, 188 were published
in the Journal of Research, and 573 in the journals of professional and scien-
tific societies. Also, 106 summary articles were presented in the Bureau's
monthly Technical News Bulletin. Seventy papers were published in the
nonperiodical series of publications: 14 in the Monograph series, 8 in the
Handbook series, 2 in the Circular series, 8 in the Miscellaneous Publica-
tion series, and 38 in the Technical Note series.

Basic Radio Propagation Predictions, the Bureau's third periodical, which
is published for a 1-month period 3 months in advance, presented radio
propagation data needed for determining the best radiofrequencies to use
in long-range radio communications.

A list of publications for the fiscal year is given in the appendix, section
3.8 (p. 176).

During the year, the Bureau participated in 21 scientific and technological
exhibitions, with exhibits depicting the Bureau's research programs. Typi-
cal of the year's shows were the Instrumentation-Automation Exhibit of the
Instrument Society of America, the Northeastern States Exposition of In-
dustrial Progress, and the National Academy of Sciences Annual Exhibit.

The Bureau's motion picture program included 3,111 showings of NBS
films to a total audience of 261,493, including educational television.

2. HIGHLIGHTS OF THE RESEARCH

PROGRAM

The Bureau's technical program is carried out through organizational
units called divisions. These are shown in appendix 4.1 in numerical order.
A review of selected research and development programs is presented in this
section under headings corresponding generally to these organizational units
but rearranged to bring together related types of activity.

2.1. PHYSICS, ELECTRONICS, AND
MEASUREMENT STANDARDS

2.1.1. METROLOGY

The metrology laboratories of the Bureau maintain, develop, and dis-
seminate standards for commonly used physical quantities, such as length,
mass, volume, density, angle, light, color, refractive index, and other optical
and photographic parameters. Included in work of the past year was the
development of interferometric methods for measuring both the surface
finish and sphericity of ball bearings, a need arising from space-age require-

ments. New single-pan two knife-edge balances, constructed in accord with
Bureau specifications, were tested and found suitable for rapid high-precision
weighing. The refractive index of specimens of calcium fluoride was
measured over a 50-fold range of wavelengths, bracketing the visible
spectrum. Progress was achieved in the re-evaluation of physical constants,
such as electronic charge, electronic mass, and Avogadro's number, through
the use of newly developed experimental data. During the year over 50,000
individual standards were calibrated for scientific and industrial use through-
out the country. Thus the metrology laboratories carry out one of the
Bureau's basic functions — to provide the means for accurate measurements
consistent with the national standards.

Wavelength Standard of Length, Direct measurements of the length
of the standard meter bar in terms of the krypton wavelength, prior to its
adoption as an international standard, verified that the new standard would
not alter effectively the unit of length which had been internationally main-
tained for over 70 years. At the time of the adoption of this wavelength
standard for length by the General Conference on Weights and Measures on
October 14, 1960, only one other laboratory besides the Bureau had meas-
ured a meter bar directly in terms of the krypton wavelength.

In this work, determinations were made of the number of wavelengths
of the orange-red radiation of krypton 86 (6054 A) in a meter. The meas-
urements were made by comparing 50- and 100-cm quartz standards and
a 100-cm steel standard with the national prototype meter bar and then
determining the number of wavelengths of the orange radiation in these
lengths. The average of a series of observations on the two quartz standards
and the steel standard gave the number of wavelengths in a meter as 1,650,-
764.13 as compared with 1,650,763.73, the value which was adopted. How-

":0Hft%

'■ :

Apparatus used in studies of the relationship between the Krypton-86 wave-
length and the meter as denned prior to the adoption of the wavelength stand-
ard. Shown is the special Michelson interferometer setup with 50-cm quartz
end standard which has been compared with the National Prototype Meter Bar
(page 21).

ever, measurements on the steel standard, believed to be the most trust-
worthy, gave 1,650,763.88 as the number of wavelengths.

A similar series of measurements on a number of different standards at the
National Research Council in Canada agreed closely with the Bureau average,
although one measurement on a Bureau meter bar by the National Research
Council — in which Bureau personnel participated — gave 1,650,763.90 as the
number of wavelengths. Bureau representatives and others at the General
Conference agreed to adopt 1,650,763.73 wavelengths, since this had the
effect of defining the Angstrom unit as exactly 10~10 meter.

The interferometric measurements were made with a large Michelson inter-
ferometer, which is enclosed in an insulated, airtight chamber with remote
controls for positioning the standards and optical elements. Remote meas-
urements of temperature at eleven stations throughout the chamber, and of
relative humidity and pressure, can also be made. The chamber is so well
insulated that the variation in temperature along the length of a one-meter
standard does not exceed 0.003 °C; it can be filled with air of known analy-
sis and the pressure maintained to 0.01 millibar.

Frustrated Total Reflection. Frustrated total reflection involves the
effect of a second surface on the complex energy existing on the dark side of
a first surface that totally reflects incident light. This phenomenon was used
to measure the film thickness existing between a glass-metal interface. The
technique, which has a theoretical sensitivity of 20-billionths of an inch, was
also employed to determine the proximity of a spherical surface to a plane.
The errors in gage-block calibration which may arise from wringing-film
thickness will also be investigated by this technique.

Mass Standards. A study was initiated to increase the accuracy of
mass measurement that is conveniently attainable through use of bulk buoy-
ancy computations of the air buoyancy. This measurement is now limited to
about 3 parts in 106 because of uncertainties associated with cavities closed
by screw knobs. Tests were started on weights of a new design which retain
the advantages of two-piece construction and provide the higher precision
and increased constancy now provided by one-piece design.

Weighing Techniques. Four experimental balances were completed.
The first two, of 6- and 50-pound capacities, are intended for use in state
laboratories where increased precision and speed of operation are required
(see p. 157). The third is a novel-type quartz microbalance of 2-gram
capacity and the fourth is a 1 -kilogram balance of advanced design which will
be used in experiments where the maximum attainable level of precision is
demanded. The first three were developed jointly with American industry
and the fourth was constructed at the Bureau.

Apparatus developed for use in knife-edge research included devices for
the measurement of knife-edge radii, friction, erosion, and the effect of
electric current through the knife-flat combination. Lathe techniques were
devised for achieving 3- to 4-microinch finishes on experimental weights
without lapping or polishing. Materials used included aluminum, titanium.

tantalum, brass, tungsten, stainless steel, and a nickel-chromium alloy.
Balance component development included an arrestment with no moving
parts and a suspension assuring minimum swinging.

Ultraviolet Wavelength Standard Developed. Glasses whose ab-
sportion spectra exhibit sharp maxima or minima have long been used to
calibrate the wavelength scale of recording spectrophotometers within the
wavelength range of 380 to 1080 millimicrons, but none has been available
in the ultraviolet range from 240 to 380 m/A. Hence a study was made, in
cooperation with a glass manufacturer, to provide a holmium-oxide glass for
use in this range. The standard glass developed has five sharp absorption
bands between 240 and 380 m/x sufficiently symmetrical that the wavelength
of maximum absorptance indicated by the recorder remains constant for slit-
widths up to 2 m/A. The standard also shows other bands between 380 and
650 m/A that are useful to supplement other standards used for this range.
The new glass, with certified values of the wavelengths of 11 absorption
maxima now being issued, makes possible a wavelength calibration accurate
to 0.1 m/A.

Filters Selected for Checking Color Measurement Equipment.
A recent advance in routine color measurement has been the development
of automatic computers, either digital or analog, that can be attached to an
automatic spectrophotometer to yield by routine measurement the tristimulus
values specifying a particular color. About one hundred such systems are
now in operation in American industry, and the current rate of increase is
about fifty per year. To provide a means for checking the performance of
such systems, the Bureau selected glass filters of five spectral types, and
determined the tristimulus values of 100 specimens of each type. If any
given spectrophotometer-integrator system yields the certified tristimulus
values for all five filters within satisfactory tolerances, it may be concluded
that the system is properly designed and adjusted. Furthermore, from the
pattern of any significant differences, definite clues are yielded as to the type
of malfunction (wavelength-scale, photometric-scale, stray-energy, slit-width)
affecting the system.

lrradiance Meters Calibrated. Cooperative work was undertaken
with the National Academy of Sciences-National Research Council and the
Department of Health, Education, and Welfare, in their study of the effect
of ultraviolet radiant energy in reducing the rate of staphylococcus infection
in hospitals. Several meters for measuring irradiance of 2537 A flux were
calibrated and one of the meters, used as a control meter, was checked
periodically during the year.

Color Names Standardized. Progress was made, in a program ini-
tiated with the Inter-Society Color Council, to establish and promote the use
of a system of simple, precisely defined, color designations. In this study, a
set of paint chips was prepared showing the most representative, or centroid,
colors for 214 of 267 ISCC-NBS color designations. Arrangements were
completed for the mass production of sets of these color standards, mounted
on charts for convenient use.

Frustrated total reflection of light was investigated through the interaction of
a steel ball and a plane glass surface. The technique has a theoretical sensi-
tivity of 20 billionths of an inch, and may provide an improved method for
measuring wringing-film thickness in gage block calibration (page 22).

The resulting charts will be suited for a variety of scientific and industrial
uses. For example, they will serve for approximate color specification
wherever the ISCC— NBS color designations are applicable, namely, in descrip-
tions of drugs and chemicals, in qualitative chemical analysis, in dermatology,
and in descriptions of mica, building materials, soils, and rocks. They will
also form the basis for statistical studies of trends in industrial color usage,
and they may be useful in planning lines of merchandise having coordinated
colors.

Artificial Daylight Standard. Since 1931 the standard artificial day-
light for color measurements in the laboratory has been based by international
agreement on two-cell, liquid filters developed at the Bureau. During the past
year a cooperative study was carried out with Corning Glass Works in which
a three-component glass filter was developed for converting incandescent-
lamp light into a closer duplication of the spectral character of natural day-
light than has previously been possible. These filters may form the basis of a
new international agreement on standard sources for colorimetry. In the
meantime they can be used as superior color-temperature-altering filters by
science and industry.

Color-Rendering Index Developed. The widespread acceptance of
fluorescent lamps of high luminous efficacy poses the problem of how closely
object colors are rendered in their natural colors by these sources. Since
1952 joint effort has been made with the Illuminating Engineering Society
to solve this problem. During the year a tentative method for specifying a
color-rendering index was developed and validated for use when the chro-

maticity of the light source to be tested is closely identical to that of the
standard against which it is to be compared.

This tentative method has been accepted by the Committee on Color Rendi-
tion of the International Commission on Illumination as one of two closely
similar methods on which the future work of that committee is to be based.
This is one step toward international agreement regarding methods of
appraising the merit of the various fluorescent lamps available in world
markets.

Specular Reflectance Standard. In cooperation with the Bureau's
enameled metals laboratory and the Army Engineer Research and Develop-
ment Laboratory, a spectral directional reflectance study was made of a
number of metals and evaporated metal films on glass. The work was under-
taken to find a suitable standard of specular reflectance in the ultraviolet,
visible, and near infrared spectra. It was found that a deposit of rhodium
on glass gave the best promise of being a permanent standard. This tentative
standard was used in a cooperative test for the University of Wisconsin, in
their work on the solar effect on soils.

Color Scale for Vegetable Oils. For many years Lovibond red
glasses have been calibrated for use in measuring the colors of vegetable oils
(cottonseed, peanut, palm) for commercial evaluation. These calibrations
have been based on a Bureau scale (Priest-Gibson) set up in 1927. As a
result of negotiations between the American Oil Chemists Society and the
makers of Lovibond glasses, and based on NBS color measurements, an AOCS
color scale has been established for the vegetable-oil industry in this country.
It is anticipated that the manufacturer will be able to supply working standards
of color to the American vegetable-oil industry which will agree with current
practice and that future Bureau calibrations will not be required.

Refractive Indices Provided. The critical components of most op-
tical instruments are the lenses, prisms, and windows. Designers of infrared
and ultraviolet devices must have accurate values of refractive index of all
available transparent materials to select optimum materials and designs for
such components. In a continuing program to provide such information, the
index of refraction of a natural and a synthetic prism of calcium fluoride
was measured over a wide range of wavelengths (0.23 to 10/x) at several
temperatures. The refractive index of six experimental infrared glasses
developed at NBS was also determined. Various components of a vacuum
monochromator system, used in extending the measurement of refractive index
and other optical properties of transparent materials into the short wave-
length region of the spectrum, were installed and tested.

Image Analysis. The evaluation of imagery concept was extended to
include the measurement of lens resolution in terms of frequency response
using either sine wave or square wave targets. In this method, the aerial
image of an infinitely distant target is scanned by a slit and photocell to read
out variations in image intensity. The lens is then treated as a low pass
filter of spatial frequencies and response is determined by comparing the
calibrated with the modulated image.

616114 0—61 3 25

Ray-Tracing Equations Developed, In the last decade a new prin-
ciple in optical design, called common path interference, has been intro-
duced and applied to interference microscopes and lens testing interferom-
eters. These devices have double-focus lenses made of uniaxial crystals that
divide a beam of light into ordinary and extraordinary rays. The design
of a common path interference device is based on the difference in refraction
of these two rays. However, because simple ray-tracing equations for the
extraordinary ray were not available, few double-focus lenses have been
designed.

The Bureau therefore developed equations which are not much more
difficult to apply than are those employed for skew rays. Moreover, they
make use of data from an ordinary ray-tracing program. These equations
are derived from the purely geometric point of view. They presuppose a
knowledge of the ordinary ray, obtainable from ordinary ray-tracing pro-
cedures together with the normal to the refracting surface. In the final
derivation both Huygen's principle and the ellipsoidal indicatrix for a
uniaxial crystal are employed.

Interference Microscope Techniques, In recent measurements of
very fine surface finishes on prepared steel surfaces, it was found that two-
beam interference microscopy did not provide sufficient resolution to dis-
tinguish small differences. Hence, commercial metallurgical microscope
components were employed to produce multiple-beam interference and
achieve the desired resolution. These components consist of cover glass
slides, coated for maximum reflectivity on one side with zinc sulfide and
coated on the other side for minimum reflectivity with cryolite. The tech-
nique was applied to the study of surface finishes on spherical surfaces of 0.5-
inch radius and on cylindrical surfaces of 0.002-inch radius.

Absolute Testing of Wavefront Shapes, A method was developed
for making absolute tests by interferometry. The process compares (1)
an unknown wavefront with a sheared image of itself, or (2) one part of a
wavefront with one or more different parts of the same wavefront, or (3)
different parts of one wavefront with another unknown wavefront. A unique
solution is then obtainable by combining simple mathematical operations.
This manner of compounding interferometry with mathematical operations
eliminates the need for reference standards and thus improves the accuracy
of the results obtained. The process has been tested and reports have been
prepared on the absolute testing of wavefront shapes that are characteristic
of aberrations of lenses and lens systems (entire optical imaging forming
units) ; shapes of optical mirrors; and image quality of simple or compound
optical systems.

Calibration of Crash Flight Record, Jet aircraft are required to
carry an automatic flight recorder which makes a permanent graph record
of such parameters as air speed, altitude, azimuth, and acceleration as a
function of time. One of these recorders, retrieved from the crash of an
aircraft in New York in December 1960, was submitted to the Bureau for
calibration of the record. Such a calibration consists of measuring the co-

Experimental one-pan balance designed to investigate the limitations of such
an apparatus in experiments where the maximum attainable level of precision
is demanded — work with the National Standard Kilogram, for example
(page 22).

ordinates at numerous positions of traces made by diamond stylii on a metal
foil capable of retaining the record and of maintaining its mechanical
strength after exposure to fire, shock, and salt water immersion. The
Bureau succeeded in extracting the record from the battered recorder, re-
moving the heavy carbon and polymer deposits from the portion of the foil
showing the latest recording from Chicago to New York, measuring the
coordinates of the traces, and with the help of the manufacturers and the
Civil Aeronautics Board, interpreting the measurements as quantitative and
correlated values of the parameters which they represented.

Photographic Density Measurements. Fine photography in science,
industry, and art largely depends on the photographic effect on a film of a
given exposure. To determine the optical density of these films, photo-

graphic step tablets calibrated at the Bureau are made available for cali-
brating the transmission densitometers used to measure optical density.
During the past year, the apparatus and method used for calibrating step
tablets were refined so that the uncertainty of measurements previously
ranging from 0.02 to 0.09 on the density scale were reduced to 0.01.

2.1.2. MECHANICS

The Bureau's work in mechanics is primarily in the development and im-
provement of methods of measurement of mechanical phenomena in solids.
liquids, and gases; the establishment of required standards in mechanics
and the relation of such standards to the prototype standards; the support
of these activities by theoretical and experimental researchers into mechanical
phenomena; the determination of physical constants of particular impor-
tance in mechanics; and provision of assistance to other laboratories in
relating their measurements to a common basis (or to established standards l
by transfer standards, calibration services, and other means. Measurement
areas include sound pressure and intensity, shock, vibration, force, strain,
pressure, vacuum, viscosity, and rate of gas and liquid flow.

These measurement areas are of vital importance in the missile and space
programs, which require great accuracies over widely extended ranges under
extreme temperature environments. Special emphasis therefore is given to
research directed toward meeting these needs.

Because of the increasing requirements for measuring mechanical quan-
tities in defense industries and in government laboratories, and because of
the requirements of missile and space projects, requests for calibration serv-
ices continued to increase. For example, during the year, more devices for
measuring force and flow were calibrated than in any previous year.

Measurement of Vibration Amplitudes. The calibration of vibra-
tion pickups, used for measuring vibrations in machines, missiles, satellites,
and aircraft, can now be accomplished by means of a recently developed
photometric system. The amplitude of vibration of one plate of a Fizeau
optical interferometer is deduced from photometric measurements on the
interference pattern. This new technique was used to calibrate pickups over
the audiofrequency range and amplitude range 72-4400 Angstroms (0.3-
17.3 microinches) , with estimated errors no greater than 2 percent. Vibra-
tion amplitudes as small as 5 A (0.02 ^in.) can be measured with uncertain-
ties no greater than 10 percent.

Calibration of Microphones. Condenser microphones calibrated by
the reciprocity technique serve as the basic standard instruments for measure-
ment of sound pressure over a wide range of frequencies. A simple method
was developed for measuring the relative response of a microphone by means
of carrier-frequency circuits. First of all, diaphragm motion is brought
about by voltage of various frequencies applied to the microphone. Then the
carrier-frequency measurement yields relative response over the frequency

range from 1 cycle per second to 50,000 cycles per second. The absolute re-
sponse can be determined at any convenient frequency by means of reci-
procity technique, and is then readily computed for other frequencies from
the relative response determined by the new technique.

Recording on Magnetic Tapes. A recording on magnetic tape under-
goes amplitude and phase changes at frequencies near the upper limit of
the pass band for the entire record-tape-playback system. For recordings of
speech or music, phase distortion is not a serious drawback since a person's
hearing is relatively insensitive to this effect. But the amplitude-equalizing
circuits frequently used in tape systems cause an intolerable amount of
phase distortion on tapes used for recording of data from measuring instru-
ments. In work sponsored by Patrick Air Force Base, a method for
minimizing this distortion was developed, thus allowing the more accurate
reproduction of complex waveforms. A new equalizer which is used can be
regarded as a filter consisting of an amplitude-equalizing network, followed
by an all-pass phase-shift network. The method will facilitate researches
into short-wavelength recording on magnetic tapes.

Analysis of Transients. Signals of importance in acoustics can be
studied as waveforms of voltage varying as a function of time, but are usually
contaminated with noise. It has been found, moreover, that there are
limitations on the amount of information, about the distribution of sinusoids,
which can be deduced in a finite time interval from a noise-contaminated
signal. The limitation depends only on the signal-to-noise energy ratio at
the input to the system. The distribution of the sinusoidal components is
found by analysis using a filter system. It appears from a study sponsored by
the Office of Naval Research that uncertainty in determination of a sinusoidal
component with any filter system is never less than that resulting from
analysis with a simple damped resonator.

Infrasonic Waves in the Atmosphere and in the Earth. Re-
searchers on naturally occurring infrasonic sound waves in the atmosphere
disclosed that those generated by geomagnetic storms approach Washington
from directions which vary during the course of the day. The variations
suggest that the source of sound in the upper atmosphere is approximately
fixed relative to the sun. The earth rotates under the source and thus the
source seems to move over the earth's surface.

Preliminary measurements on infrasonic waves having quite constant
periods — near 6 seconds — showed that these waves usually come from east-
erly directions, and seem to travel through the atmosphere almost parallel to
the earth's surface. These atmospheric waves, usually called microbaroms,
occur often in the Washington area.

Research having to do with infrasonic waves in the earth also was carried
on during the year. This research was aided by a reliable instrument system
for measuring vibrations of the earth, developed from study of the electro-
mechanical equations of motion of a seismometer-galvanometer system. The
seismometer itself is stable with respect to variations in the local gravitational

Calibrating an infrasonic microphone (front, connected by a hose to the cali-
brating barrel) used to study naturally occurring infrasonic sound waves in
the atmosphere (page 29).

field, as well as for large variations in barometric pressure, and temperature
changes in the range —40 °F to 120 °F. The instrument was designed for
the pass band 1 to 5 cycles per second with a system noise level at least one
decade lower than the seismic noise at the quietest known location on the
earth's surface. It can be used for other pass bands at some sacrifice of
signal-to-noise ratio.

It is planned to use at least three of these systems in the Washington area
with seismometers spaced far enough apart to allow determination of the
propagation speed and direction for microseism waves in the earth's crust.
Such waves have periods of about 6 seconds, as do the microbarom waves in
the atmosphere. The origins and interactions of these two types of waves are
still obscure and require elucidation.

Ultra-High-Pressure Measurements* Work continued with the mul-
tiple anvil devices capable of generating pressures in excess of a million
pounds per square inch. The technique of preparation of the samples and
operation of the apparatus was refined until the pressures reached in an
experiment can be predicted within a few percent, as compared with 20
percent a year ago. A device using six anvils pressing on the faces of a
cube was put into operation. This can reach pressures nearly as high as
those obtained with the four-anvil tetrahedral apparatus. With the six-anvil

device the pressures are more nearly hydrostatic and somewhat more
reproducible.

Study of Convective Currents in Water, In an investigation of pos-
sible methods for detecting motions within a body of water, schlieren optical
techniques, commonly used to observe shock waves in supersonic aero-
dynamics, were found to be so sensitive that convection currents resulting
from evaporative cooling at the surface could be studied in detail. The
schlieren method proved to be important in detecting and measuring motion
involving temperature differences as little as 0.01 °C and possibly smaller.
The phenomenon observed was a pattern of plunging currents resulting from
instability of the cooled surface layer.

When a container of still water was first uncovered, a cooled surface layer
was seen to develop. Within seconds, local thickening developed along
irregular lines; and in these regions the cooled liquid plunged in descending
sheets. Simultaneous photographs from the top and side of a glass con-
tainer revealed configurations which changed slowly with time but persisted
indefinitely. Independent measurements of the temperature gradient deter-
mined the conditions under which instability of the surface layer set in and
conditions for maintaining the currents. Thus, in what to the naked eye
appeared to be still water, there were usually present the sharply defined
sheet-like currents descending through the surrounding water whenever
evaporation was taking place from the surface.

Internal Waves in Water with Uniform Density Gradients. As
part of an investigation of internal waves, sponsored by the Office of Naval
Research, the phenomenon of wave production was studied when there existed
a uniform density increase from the surface downward. It was known
beforehand that waves would form at the interface between two distinct layers
of different density much as they do at a water surface. The year's work
showed that motions wavelike in character also ensued due to the movement
of a body through liquid when there was a uniform variation in density.

The body in this case was a lenticular cylinder moved through water 50
centimeters deep in a long channel. A density gradient from top to bottom
was produced by varying the salinity. The motions were observed in part
by instruments and in part by photographic techniques through dyeing
alternate layers to produce a field of parallel stripes.

Force Measurements. The advent of missiles and space exploration
has led to requirements for load or force measurements that exceed the
Bureau's present capabilities for accuracy and magnitude. To meet these
needs three new dead weight machines of 113,000-lb, 300,000-lb and 1,000,-
000-lb capacities will be installed in the new Engineering Mechanics Labora-
tory at Gaithersburg, Maryland to supplement the two existing machines of
10,100-lb and 111,000-lb capacities. Meanwhile, the existing machines will
be modernized before being moved to Gaithersburg.

During the year the designs of the new dead weight machines were almost
completed and some of the major components were under contract. These

machines will apply loads accurate to 0.01 percent or better in tension and
compression.

The Bureau's 1,000,000-lb and 3,000,000-lb elastic load-measuring devices
were recalibrated and used to calibrate a load cell to 6,000,000 lb. This is
though to be the largest portable load measuring device in existence. It is
believed that the error of the applied loads did not exceed 0.3 percent.

Clamping Force of High-Strength Aircraft Bolts, At the request
of the Bureau of Naval Weapons, tests were made to determine the feasibility
of predicting the clamping force of an installed high-strength aircraft bolt
by measuring the amount of torque applied to the nut or bolt under dry and
lubricated conditions. This method has long been in use for installing non-
lubricated low- and intermediate-strength aircraft bolts, but limited data are
available for the intermediate-strength type.

Tests were carried out during the year to evaluate performance of a special
machine for applying torques, and of special load cells for measuring torque
and clamping force. Modifications were made to obtain optimum perform-
ance. The relationships between torque and clamping force were determined
for two diameters of bolts with minimum tensile strengths of 180,000 lb/in.2
when used as fasteners of aluminum, steel, and titanium joints.

Mechanical Properties of Materials at Elevated Temperatures,
Nose cones of manned spacecraft should be fabricated from materials which
can withstand very high temperatures without loss of structural integrity and

Diamond grown in multi-anvil (tetrahedral) apparatus at a temperature of
3000 °F and one million pounds per square inch pressure. This work is aimed
at establishing fixed reference points on the pressure scale (page 30).

which will dissipate heat by radiation. This will be particularly critical
when such craft must make more than a single flight.

To provide means of evaluating materials for this purpose, apparatus and
techniques for conducting mechanical tests at temperatures approaching the
melting points of the refractory metals were developed under a program
supported in part by the Office of Naval Research. An optical technique for
accurate measurement of strain was pursued for use on tensile specimens
tested at 3,000 to 4,000 °F in a vacuum. Using carefully selected filters,
water-cooled viewing ports, and motorized cameras, high-resolution photo-
graphs of the specimens were made; and the relative displacements of grid
lines on the specimen surfaces were measured with reference to a fixed
fiduciary grid network which was a part of the optical system.

Rheology of Liquids, Rheology, which is the study of the flow of
various materials, is important for an understanding of the behavior of these
materials. One phase of rheological study at NBS concerned a mathematical
bounding technique, which permits the calculation of exact limits for the
effects of inertia on certain flows. The technique was described in 1960
"Research Highlights" (p. 55) . Further applications of this technique were
investigated during the year with the objective of establishing limits on
inertial effects for selected flow geometries. A first step toward the separation
of rheological nonlinearities from thermal effects was accomplished through
the calculation of the effect of viscous heating on the flow through a pipe of
a liquid whose viscosity varied exponentially with temperature. The results
suggested that certain experimental observations generally attributed to non-
linear constitutive equations of the material might be due instead to these
thermal effects. Further calculations for a geometry which should permit
a definitive experimental verification are underway.

New measuring techniques which will permit the absolute measurement
of the viscosity of a liquid by eliminating inertial effects from the measured
quantities are also under development. These techniques will still require
some independent estimate of the magnitude of possible thermal effects.

Additional information on the relation of the effects of temperature and
pressure on the rheological properties of rubberlike polymers, which are
essentially complicated liquids, was obtained through the study of the complex
bulk compliance of polyvinyl acetate. These results suggested that the free
volume concept, which has led to a simple presentation of the influence of
temperature on the rheological properties of a wide variety of polymers and
the effect of pressure on these properties for a limited number of polymers,
may need some modification or elaboration.

High-Temperature Thermocouples. Measurements of thermal emf
were completed on thermocouples of 40 percent iridium-60 percent rhodium
versus iridium at temperatures up to 3,800 °F. Reference tables were com-
piled for this combination. Work was continued, using the same experi-
mental procedure, on alloys of iridium with 40 and 50 percent rhodium
against iridium.

Calibrating the world's largest proving ring, capable of measuring forces up
to 1,200,000 lb. With present facilities, the Bureau can calibrate such devices
only to 110,000 lb. with deadweights; beyond that, indirect methods are used,
with a resulting loss of accuracy. Three deadweight machines, the largest
having a capacity of 1,000,000 lb., are being designed for the new NBS labora-
tories in order to increase the accuracy of such calibrations (page 31).

Catalytic Effects of Thermocouple Materials. In analysis of many
industrial processes involving combustion of fuels such as hydrocarbons in
air, it is often necessary to determine the temperature of exhaust products
containing appreciable amounts of combustible gases and oxygen. This is
particularly true in performance evaluations of gas-turbine power plants.

In this connection, it has long been known that platinum is a fairly good
catalyst for many oxidation reactions; and early work at NBS showed a
platinum shielded Chromel-Alumel thermocouple to indicate as much as 25
°F higher than the temperature of exhaust gases containing a small amount of
unburned hydrocarbon. As a result of these findings, the Aeronautical
Systems Division of the Air Force sponsored a program at NBS to determine
the catalytic effects of all of the commonly used thermocouple materials.

The experimental technique utilized the resistance of electrically heated
test wires of thermocouple elements to determine their temperatures. Power
requirements at given wire temperatures were compared for low-velocity
streams of dry air and of combustible mixtures to determine the magnitude
of the thermal contribution from catalytic combustion. Experiments were
conducted in mixtures containing up to 3 percent by volume of hydrogen,
carbon monoxide, methane, and propane in air flowing at gas velocities from
0.16 to 4.38 cm/s over the resistance element.

No catalysis was exhibited by resistance elements made of gold, silver,
Chromel, Alumel, or constantan. However, all resistance elements containing
either platinum or palladium catalyzed the reaction of all combustible mix-
tures tested except those of methane. The magnitudes of the catalytic effects
and their temperature limits, up to 2,000 °F, were determined; and some
anomalous behaviors were explained.

Hyper velocity Missile in a Combustible Gas. Stabilization of hyper-
sonic combustion appears to be a prelude to its application to propulsion at
hypersonic speed. With a view to this application, research on stabilization
and properties of this kind of combustion continued by observation of a
hypervelocity missile in a stationary combustible gas. In this program,
sponsored by the Air Force, experiments showed that, as in nearly all com-
bustion processes, oscillations driven by combustion may be expected at
extremely high frequency. The likelihood of generation of thrust by com-
bustion on external missile surfaces is suggested by a large reduction of the
drag coefficient of the missile under certain conditions.

The experimental technique developed for these studies also permitted
observations on the structure of detonation waves. Detonation appears as a
shock wave followed by a combustion wave. The observed spatial separation
was converted to ignition delay times, which in these experiments ranged
from about one to ten microseconds. Chemical kinetics of chain-branching
and chain-breaking reactions in the mixture of hydrogen and air were used
to correlate and explain the observed delays.

Fuel Flowrate Studies. Under sponsorship of the Bureau of Naval
Weapons, progress continued on the fuel flowrate standardization program
for the aircraft industry, and on the evaluation of flowmeters. Many
transfer reference meters were calibrated with liquid hydrocarbons for the
Armed Services and for industry, in order to evaluate the accuracy of cali-
brators installed at other locations. The results of investigations over the
past several years on turbine flowmeters were summarized for publication.
It was shown that metering precision better than 0.2 percent was obtained
for selected ranges of flowrate and viscosity when entrance conditions and
meter orientation were suitably controlled. The readout instrumentation
and transient response were also discussed.

Through such work more accurate flowrate calibration facilities are being
maintained in the aircraft industry, and more suitable fuel flowmeters are
being developed and manufactured.

2.1.3. ELECTRICITY

The Bureau's work in electricity is primarily the development, improve-
ment, and dissemination of the standards of measurement for electrical
quantities; and the study of the electrical and magnetic properties of mate-
rials. Electrical standards must be established that are constant over long
periods of time, uniform throughout the Nation, and compatible with other
standards used throughout the world. Measurements of electrical quantities
directly in terms of length, mass, and time ("absolute measurements") are
extremely difficult and are made only in the realization and confirmation
of electrical standards of resistance, capacitance, inductance, and voltage.
Calibration work is done by comparision with these electrical standards.

Absolute Measurement of Resistance, An evaluation, based on the
prototype standards of length and time, of the unit of resistance maintained
at the Bureau was completed. The evaluation was based on a nominally
1-picofarad symmetrical cross capacitor having a value computable to high
accuracy from its mechanical dimensions. The computable capacitor was
used to establish the value of a 0.01-microfarad capacitor which then, through
the medium of a frequency-dependent bridge, established the value of a
10,000-ohm resistor. A comparision of that resistor with the group of
1-ohm standard resistors currently used to maintain the NBS unit of
resistance established the value of the unit with an estimated accuracy of
the order of 2 ppm.

It is expected that an even higher accuracy will be attained in the repetition
of these measurements. This method will greatly improve the Bureau's
ability to check maintenance of the unit of electrical resistance through the
use of a group of standard resistors. When combined with repetitions of
determinations of the gyromagnetic ratio of the proton, the method can be
used as a check of the stability of all types of electrical standards to a much
greater accuracy than previously possible.

Standard Cells Under Vibration, Standard cells are normally used
under vibration-free conditions. Even so, the question frequently arises
as to the effect of vibration on the electromotive force of standard cells.
The Bureau exposed a number of unsaturated standard cells to vibrations
at frequencies from 5 to 2,000 c/s and applied forces from 1 to 30 g. With
a d-c galvanometer used as null detector, such vibrations appeared to have
insignificant effects. However, when observations were made with a
cathode-ray oscilloscope, an a-c voltage was observed. At frequencies
above 150 c/s, the magnitude of the a-c voltage appeared to be dependent
on the applied force and to range from 20 to 120 microvolts. At frequencies
below 150 c/s, the magnitude of the a-c voltage was no longer proportional
to the applied force because of the resonance of various components,
especially free mercury above the cell septa. Vibrations of these magnitudes
have no lasting effects on the electromotive force unless the cells are quite
old or exhibit excessive hysteresis; in such cases several days may be required
for the cells to recover their initial electromotive force.

Electrode Kinetics. Electrode reaction mechanisms may be studied
in many ways. One method, presently under consideration at the Bureau,
involves the measurement of the impedance of electrode-electrolyte systems
as a function of the frequency of an applied alternating field. The kinetics
were studied in terms of electrode relaxation processes using alternating
currents of frequencies from 50 c/s to 50 kc/s. Electrodes studied included
silver, cadmium, zinc, and manganese dioxide. The last two electrodes were
also studied in combination in dry cell electrolytes. Equations based on
electrostatics and electrodynamics were developed to explain observed
phenomena. Two electrode processes occur at manganese dioxide electrodes ;
whereas a single process, namely, simple charge transfer, occurs at the other
electrodes. The exchange currents of silver in silver nitrate and of cadmium
in cadmium sulfate were found from impedance measurements at low and
high frequencies to be 110 amp/m2 and 140 amp/m2, respectively.

Assembling the gage blocks used to form the NBS computable cross capacitor.
The capacitor was used to re-evaluate fundamental unit of resistance in terms of
the prototype standards of length and time (page 36).

Electrical Properties of Molecular Solvents at High Temperature.

There are very few data on the behavior of dilute solutions of electrolytes
in molecular solvents at high temperatures. Nonionic solvents at high
temperatures are few in number and there is a need for extensive study of
their properties. At present, the dielectric constant of boric oxide is under
study at the Bureau. At frequencies from 1 to 2 kc/s, both dielectric
constant and loss increase sharply above 500 °C; the dielectric constant
rises to above 300 at 900 °C, indicating that very large units of the three-
dimensional boric oxide must be inferred if one is to interpret the electro-
lytic conductivity and the interionic attractions of salt solutions made with
boric oxide solvent. Measurements of these values are now in progress.

Metal Oxide Solubilities in Molten Salts. Electrochemical corro-
sion of metals in molten salts at elevated temperatures is greatly influenced
by the oxygen content of the environment. As a part of a broad study on this
problem, the Bureau determined the solubility of the oxides of the metals of
the first transition series (titanium, vanadium, chromium, manganese, iron,
cobalt, nickel, and copper) in molten sodium chloride at 900 °C. Vanadium
pentoxide reacts violently with molten sodium chloride to form chlorine,
whereas the oxides of the other first transition metals are stable and only
slightly soluble (less than 0.1 mole percent) in molten sodium chloride.
Results for Cu20, CoO, and Mn304 indicated that the mechanism of dissolu-
tion is complex, since the metal-oxide ion ratio is several times greater than
would be expected for a simple solution process. Furthermore, the solubilities
of the oxides, although low, are much greater than would be indicated by
thermodynamic calculations.

Metal-Molten Salt Interactions and Stoichiometry. Extensive mass
transfer is commonly observed for metals immersed in molten salts at elevated
temperatures. Such transfer limits the use of molten salts as heat exchangers
and the range of use of reference electrodes in molten salt systems. Reactions
between silver and molten sodium chloride were investigated at 820 °C and
940 °C in a pure oxygen atmosphere and in a nearly oxygen-free (10~5 arm)
environment. In each case, silver and oxide ions are formed in the melt with
the concentration of the silver ions exceeding that expected from the stoi-
chiometry of monovalent silver oxide. At low oxygen pressures, less than
0.2 atm, the rate of silver-oxygen interaction is zero, or independent of the
oxygen pressure. At higher oxygen pressures, the rate is controlled by
diffusion of reaction products away from the reaction site. If the solubility
product of the oxide is exceeded locally by slowness of diffusion, metallic
silver crystallizes out since the oxide is unstable. This process accounts for
extensive mass transfer of metallic silver in molten sodium chloride.

Differential Thermocouple Voltmeter. A basic problem in elec-
trical standardizing laboratories is the transition from d-c measurements
(which are closely related to the fundamental standards) to a-c measurements
at power and higher frequencies.

A recent contribution of the Bureau to the solution of this problem con-
sists of the development of a "differential thermocouple voltmeter."' This

A study of the effects of vibration on the performance of standard cells showed
that an a-c voltage was produced during vibration, but that no permanent
damage resulted (page 36).

instrument includes two equal thermoelements, one supplied by an unknown
voltage and the other supplied by a highly stable reference voltage. The
thermoelement supplied by the unknown voltage is in series with a decade
resistor. The dials of this resistor are read directly in volts and so can
be set to indicate the nominal value of the unknown voltage. The percentage
difference between the unknown voltage and its nominal value as determined
from comparison with the reference voltage is then read directly on a
galvanometer.

Magnetism* The nuclear magnetic resonance of Ni61 was observed in
99.97 percent pure nickel metal. It was found that the resonance occurs

at a frequency of 26.1 Mc/s at room temperature with a line width of about
50 kc/s. The temperature dependence of the frequency was measured over
a temperature range from 77 to 536 °K, and the effect of an externally
applied field on the intensity of resonance was observed. The Ni61 resonance
was also observed in 99.7 percent pure nickel with substantially the same
results as with the purer sample. Studies are in progress on the resonance
in nickel-rich alloys.

A special susceptibility apparatus was constructed for measuring the abso-
lute susceptibility of small samples (less than 0.5 gram) and single crystals
by means of a quartz beam balance. This apparatus is designed to measure
the primary static susceptibilities of paramagnetic substances while a given
microwave magnetic field is being applied. The apparatus also provides
for relative measurement of greater sensitivity of susceptibilities by use
of a vibrating magnetometer method. Preliminary measurements are now
being made with the apparatus of the primary susceptibility of single crystals
grown in this laboratory.

Analysis of the Melting Point of Polychlorotrifluoroethylene. The
observed melting point of the linear polymer polychlorotrifluoroethylene was
experimentally determined to depend strongly on its original crystallization
temperature. The observed melting point rises with crystallization tempera-
ture. (Results of this type have been known in other polymers for many
years.) This interesting phenomenon was explained in terms of the behavior
of chain-folded crystals, and the experimental data were used to estimate
the equilibrium melting temperature of the polymer.

Analysis of the Dielectric Properties of Polychlorotrifluoro-
ethylene. Data obtained from a previous detailed experimental study on
polychlorotrifluoroethylene were analyzed to reveal the contributions of the
crystalline and amorphous regions of this semicrystalline polymer. One of
the loss processes in the polymer is associated with the freezing out of long-
range molecular motions that are associated with the onset of the glass
transition in the amorphous component at 52 °C. At a given frequency.
say 1 c/s, the dielectric loss peak associated with this mechanism corresponds
closely with a mechanical loss peak observed by others. The activation
energy exhibited by this process is large and strongly dependent on tem-
perature. At low temperatures, far below the glass transition, the amorphous
component exhibits an additional and very prominent dielectric loss mecha-
nism, which is a result of short-range motions in the glassy state of the
polymer. The activation energy of this process is small (about 60 kj /mole)
and independent of temperature. This process also possesses a mechanical
analog — the crystals in the polymer exhibit a marked dielectric polarization
which is associated with a very rapid dipolar re-orientation process, probably
a twisting mode. Evidence exists that in highly crystalline specimens the
amorphous material still remaining has somewhat abnormal properties.
Foremost among these is an elevated glass transition temperature. The prop-
erties of the liquid polymer above the melting point, which is 221 °C, exhibit
the customary negative temperature coefficient.

Finding the frequency response of a differential thermocouple voltmeter. This
instrument is a recent contribution to the solution of the problem of transfer
from d-c and a-c measurements at power and higher frequencies (page 38).

Dielectric Properties of Poly par achlorostyrene and Polymeta-
chlorostyrene. Polyparachlorostyrene is a molecule which, in effect, has
a large dipole moment that is attached at a right angle to the main polymer
chain backbone. Thus, a motion of the main chain is required to permit
reorientation of the dipole moment and dielectric loss. Dielectric measure-
ments on this noncrystalline polymer in the glassy state reveal no evidence
of molecular motion, even at low frequencies.

The situation is radically different in the case of polymetachlorostyrene.
In this material, dipolar orientation can be effected by allowing the benzene
ring side group to turn about the bond connecting it to the polymer chain
backbone. Dielectric measurements have confirmed that such a motion
exists even well below the glass transition temperature, since a large di-
electric loss is observed. This work discloses an excellent example of
dielectric loss due to hindered internal rotation in a polar side group
substituent on a polymer chain.

2.1.4. RADIO STANDARDS

The Bureau program in radio standards, centered at the Boulder Labora-
tories, consists of basic research and development of national standards of
fundamental electromagnetic quantities, measurement techniques, and prop-
erties of materials. A large calibration service is provided from direct

616114 o— 61-

current through microwave frequencies, and radio broadcasts are made of
the national primary standards of frequency and time intervals.

Probably the most striking developments during the past year, scientifically
and internationally, were in the area of frequency standards. International
comparisons of the atomic beam frequency standards of the United States,
England, and Switzerland indicate continued agreement to within 1 or 2
parts in 1010. The United States standard has also been compared daily
with commercial standards and has operated on a routine basis throughout
the year. All indications are that the United States Frequency Standard is
performing at the estimated level of stability. This performance, and the
performance of frequency standards in other parts of the world, has led to
active consideration on the international level of a redefinition of the second
in terms of an atomic transition.

During the year several conferences designed to define and resolve major
problems in electronic measurement were held. A series of measurement
research conferences between industry and NBS, initiated by the Aerospace
Industries Association, is continuing to probe each field of measurement
in depth. In the area of electronic measurement the first such conference
was held during May 1960, and considered measurement and calibration
problems in the fields of microwave power and attenuation. Additional
conferences in this area were held during January and June 1961, and con-
sidered the same problems in the fields of pulsed signals, sinewave rf signals,
and rf and microwave noise and impedance. These conferences help define
what ranges and accuracies are most needed in these fields, why they are
needed, and what immediate and long-range action might best be taken by
the Bureau, industry, the military, and scientific organizations.

At the suggestion of several defense agencies, the Electronic Calibration
Center provided a 5-day workshop — covering microwave frequencies — for
about 40 technical supervisors from a large number of standards laboratories
in the Department of Defense. Basic theory of the precision measurement
of power, impedance, frequency, attenuation, and noise was covered in half-
day sessions for each quantity. Equal time was spent in the laboratory to
provide the opporunity of viewing measurement equipment in actual use.
This kind of effort, by improving measurement competence in laboratories
of industry and defense, multiplies the effectiveness of NBS.

The Bureau also served as host for a meeting on high precision con-
nectors. It is expected that the ideas expressed at this meeting — by dif-
ferent manufacturers and NBS — will lead to much better measurement
equipment in this field and to a standardization of the instruments and tech-
niques involved.

Theoretical Physics. Studies in theoretical physics and applied
mathematics (including numerical analysis) contribute to the more basic
work of the entire radio standards program. These studies are an end
product in themselves and, on occasion, provide key theoretical develop-
ments upon which further work in other projects may be based.

Perturbation formulas, based on a "compensation theorem" stated for
waveguide junctions, were used to obtain approximate results in a variety
of waveguide problems. One such problem, for example, was that of re-
flection at the junction of a perfectly rectangular waveguide with a filleted
rectangular waveguide of the same main dimensions. The theoretical re-
sults of this problem are being compared with NBS experimental results.
The perturbation formulas were also applied to theoretical results which
are already available and it was found that the common expedient of using
an unperturbed field, as an approximation to an unknown field, does not
always lead to a correct lowest-order approximation.

Radio Plasmas, Radio waves and plasmas are intimately connected
in that each can be used as a tool to study tr other. For example, radio
waves are used to create plasmas and to determine their properties ; plasmas
are used in such microwave devices as TR switches, noise sources, modula-
tors, couplers, and harmonic generators.

A current objective in this area is to understand all modes for the propa-
gation of energy through plasmas, including both electromagnetic and
plasma waves. Theoretical and experimental progress was made in under-
standing the many possible electromagnetic modes in a cylindrical plasma,
and especially the effect of placing bounding surfaces on a medium sup-
porting the "whistler" mode.

A Fabry-Perot Interferometer, designed to operate at millimeter wavelengths,
is being used as the cavity resonator for a hydrogen cyanide gaseous maser.
The device shows promise for frequency standard applications, and in micro-
wave spectroscopy. Bi-conical, spherical cavity (inset) illustrates the design
flexibility of the perforated cavities (page 44).

Atomic Frequency and Time Interval Standards. The previously
observed difference of 1.5 X 10"11 between the two NBS atomic frequency
standards was carefully remeasured and found to have remained constant
to at least 2 X 10-12 over the year. In an initial experiment with thallium, a
thallium beam was successfully detected but with low efficiency. Experi-
ments which used an ammonia maser to excite the cesium resonance resulted
in measurement precisions of 3 X 10"12 in periods of only a few minutes.

In these measurements precision refers to the reproductibility of several
consecutive measurements of a very stable oscillator. Each such measure-
ment may require several minutes and consists of an average of 15-25 sep-
arate determinations of the oscillator frequency. The accuracy of the NBS
standards is considered to be 1 X 10"11 and refers to the maximum expected
deviation of the measured frequency of either standard from the idealized
Bohr atomic resonance frequency. The accuracy estimate is obtained by
adding up all uncertainties associated with certain parameters in the system
which may affect the measured frequency.

A servo system for locking a 5 Mc/s quartz crystal oscillator to the cesium
atomic resonance was completed and extensively tested. The system op-
erated satisfactorily although a small, systematic frequency shift may be
introduced if proper precautions are not taken. Tests were begun on a
servo system for the second cesium standard.

Refinements of an ammonia beam maser permits the maser frequency to
be reset to about 3 parts in 1011 by comparison with the cesium beam. This
was accomplished by construction of a new servo system which constantly
controls the cavity tuning of the maser. The correction signal is obtained
by Zeeman modulation of the ammonia line. With this development the
ammonia maser can be seriously considered as a secondary standard of
frequency.

A Fabry-Perot maser was constructed which offers the potential of a
highly-stable signal source, at millimeter wavelengths, for frequency stand-
ard applications, and for applications in microwave spectroscopy — both
maser and absorption spectroscopy — at similar high frequencies. This in-
strument, a hydrogen cyanide gaseous maser, is designed to operate at a
wavelength of 3-4 millimeters and uses a millimeter wave Fabry-Perot inter-
ferometer in place of the conventional cavity resonator. The Q of the inter-
ferometer was observed to be 32,000, and work is in progress to observe
maser oscillation at 88.6 Gc/s.

Construction was begun on a new beam tube to increase the length of the
U.S. Frequency Standard apparatus, and thus reduce the spectral line width
by a factor of %; on a third atomic beam frequency standard which will
have an oscillating field separation of about three meters; and on a hydrogen
atomic beam maser which should have a higher ultimate stability, at micro-
wave frequencies, than existing masers.

Radio Broadcast Service. Propagation data continue to demonstrate
that low and very low frequencies, because of their high phase stability, are
a much more accurate method of distributing standard frequencies over great

distances than the short wave broadcasts of WWV and WWVH. The lower
frequencies also offer the potential of greatly increasing the accuracy of
time signal transmission. This is of particular importance to the satellite
and missile programs of the armed forces and of the National Aeronautics
and Space Administration.

Therefore, substantial effort is being devoted to the establishment of a
20- and 60-kc/s station at Fort Collins, Colo., which will have a much higher
radiated power than the existing stations near Boulder. The 60-kc/s trans-
mission will include precise time information, and both transmissions will
be directly controlled by the U.S. Frequency Standard (USFS) . Designs have
been established for the major components of both transmissions, and con-
tracts were let for many of the 20-kc/s components.

The standard frequency 20-kc/s transmissions from WWVL, Sunset, Colo,
(about 20 miles from Boulder), have been given continuously, as scheduled,
since April 1960. Broadcasts were monitored in Boulder by three different
methods, all methods were referred to the USFS, and all results were the same
except for very small instrumentation errors. The long-term stability of the
transmitted signal (quartz oscillator control) was normally maintained within
2 parts in 1010 of its assigned value.

WWVL is also serving as an important experimental tool for studying
the design problems of the 20-kc/s station to be built at Fort Collins. A
closed-linked radio system — to phase lock the WWVL carrier to a standard
frequency at Boulder — was designed, built, and tested. Results indicate
that the phase of the 20-kc/s transmission can be held well within one
microsecond of the USFS.

Initial steps were taken toward the establishment of an atomic time
scale — capable of being synchronized or related to clocks at any remote
location — by completing part of the redundant circuitry for supplying an
unfailing frequency source referenced to the USFS.

The accuracy of the WWV frequency transmission was increased by using
measurement methods based on the LF and VLF transmissions. The maxi-
mum uncertainty is now 5 parts in 1011 Also, WWV began regular broad-
casts of a timing code which gives the second, minute, hour, and day of
year. This code is used to synchronize time generators at widely-scattered
observation stations, and to automatically place time information on re-
corded telemetry signals from satellites and rockets.

High-Frequency Electrical Standards. In the high-frequency range,
approximately 30 kc/s to 1,000 Mc/s, the emphasis and major achievements
were in the fields of noise, power, and attenuation.

A comprehensive theory of a spectral density noise comparator was com-
pleted. This comparator, now under construction, should provide high
stability, high sensitivity, and be capable of precisely measuring the ratio
of noise sources over extremely wide ranges.

An experimental model of a stable, temperature-limited, thermionic-diode
noise generator — with its plate current stabilized to the equivalent of 0.001 db

Reflectometer used to measure VSWR of coaxial components, extensively used
in radio and telephone communication links. The instrument measures mag-
nitudes of reflection coefficients to better than one percent (page 47).

of noise power — was developed, and construction was nearly completed on
a permanent laboratory model.

A series of directional coupler power meters were developed and calibrated
for the NBS Central Radio Propagation Laboratory. These were built
for use at 40.92 Mc/s and 49.92 Mc/s at power levels of 300 kw cw and
1.5 megawatts peak pulse.

A directional coupler transfer standard was developed for international
comparison at 300 Mc/s and an absolute power level of 100 milliwatts. Pre-
liminary results from the initial comparison (with Great Britain) indicate
agreement of better than 0.5 percent.

A coupler for 600-ohm balanced-line power measurements, with an ac-
curacy of better than 10 percent, was developed and built for 4 to 60 Mc/s
at 1 megawatt peak pulse power. The variations in repeated measurements
of a calorimetric power standard, whose power range is from 0.05 to 5
watts, was reduced from 0.2 percent to less than 0.05 percent.

A sensitive detector, to be used for systems of precise attenuation measure-
ment, is under design and construction. This will simultaneously indicate
the direction of adjustment for both phase and magnitude controls in com-
plex attenuation measuring systems.

When systems of attenuation measurement have sensitivities of 0.001 db
or better, the stability of the various components can be very critical. To
detect and evaluate instabilities a device was developed which has detected
impedance changes in the order of 0.001 percent. It is also applicable to
other quantities.

Microwave Circuit Standards. Measurements of the field strength
and gain of microwave antennas are required to lay out radio and telephone
communication links and to determine if radiation levels near the transmit-
ters are hazardous to personnel. However, when measuring the gain of stand-
ard microwave horns in the laboratory, one problem has been that measure-
ments of the antenna itself are complicated by multiple reflections from the
walls and nearby objects.

During the past year substantial progress has been achieved in develop-
ment of a technique which can discriminate between radiation from the
horn and reflections from within the laboratory. This involves the genera-
tion of pulses which are only a few nanoseconds (a thousandth of a millionth
of a second) in length, methods to detect the amplitude of these pulses to
0.01 db, and methods to discriminate against pulses arriving as little as 5
nanoseconds after the main pulse. The short pulses have been produced and
a method to detect their amplitude to within a few hundredths of a db
appears to be successful. Discrimination against the delayed pulses is pres-
ently limited to about 10 nanoseconds but a method of reducing this appears
feasible and is being evaluated.

During the fall of 1960 three papers were published which specify the
techniques required to measure microwave phase shift and which analyze
the errors involved. This method is being adopted by various laboratories
to establish a calibration service and also to measure phase shift in certain
types of antennas.

A technique was developed, and the instrumentation completed, for a sys-
tem to accurately measure VSWR of coaxial components at 4 Gc/s. This
system is constructed entirely of rectangular waveguide except for the coaxial
unit being measured and the uniform line to which this unit is attached.
The instrument can measure magnitudes of reflection coefficients (over an
intermediate range) to better than one percent.

The largest single source of error was eliminated in the NBS microwave
radiometer. In the radiometer method of noise source comparison used
at NBS the bandwidth is determined by a superheterodyne receiver. An
inherent characteristic of such receivers is that they respond simultaneously
to two discrete frequency intervals (signal and image channels). Hereto-
fore the radiometer has been tuned for the median frequency between these
two bands. A new technique, however, permits the radiometer to be tuned
for optimum performance at the two frequencies simultaneously.

The impedance technique of measuring barreter mount efficiency has been
refined to the point that calorimetric and impedance measurements agree
within a few tenths of one percent. Since the two techniques are completely
independent, the impedance technique provides a valuable cross check in
microwave power measurements and it is also more easily adapted to the
larger waveguide systems.

Thirty bolometer mounts were calibrated and turned over to the Electronic
Calibration Center to support its calibration service. A new microcalorim-

eter was nearly completed which will extend the frequency range of the
national standards to the region of 12.4 to 18.0 Gc/s.

Millimeter- Wave Research. The millimeter region of the electro-
magnetic spectrum — between wavelengths of about 3 mm and the long
infrared — is virtually unused since these waves cannot be' generated or
detected with conventional electronic techniques. NBS research in this area
is aimed at developing the special techniques and radio standards required
to use these frequencies effectively.

New plates, used to contain the resonance region, were designed for the
millimeter wave Fabry-Perot inteferometer. These consist of perforated
films of silver deposited on glass and have resulted in better performance,
easier adjustment, and easier fabrication. The interferometer has been used
to measure the length of millimeter waves and has achieved accuracies of
better than four-hundredths of one percent. In experiments with waves
about 6 mm long the resonant cavity attained Q values of around 100,000.

A theory and technique were developed for using the interferometer to
measure dielectric constants and loss tangents of materials in sheet form.
Measurements were made on plexiglass, polystyrene, and teflon with satis-
factory results — the first such measurements known to be made in this region
of the electromagnetic spectrum.

The perforated reflectors are not limited in shape and a reentrant bi-
conical sphere was designed to test the spherical concept. This particular
unit is four inches in diameter, and two sides of the sphere are perforated.
Energy was focused at the center of the sphere, and it operated successfully
at a wavelength of eight millimeters. This type of device shows great
promise as a tuned resonant cavity for the generation of harmonic power at
millimeter wavelengths. It offers a possible solution to the problem of
designing a resonator, at these wavelengths, for two- and three-level solid-state
masers.

A specific objective in this area is to make a redetermination of the speed
of light, using a wavelength of 6.28 mm, and a millimeter wave Michelson-
type interferometer operating in the Fresnel region of diffraction. A five-
foot square aluminum reflector with precision carriage has been set up and
most of the preliminary adjustments have been made. The refractometer
is operable, and the instrumentation for the antenna pattern analysis is
almost completely assembled.

Radio and Microwave Materials. Research in this area emphasizes
the viewpoint of solid state physics in studying the interaction of electro-
magnetic waves and matter, particularly as this applies to the establishment
and improvement of standards and measurement techniques. The prime
interest is to acquire an understanding of the magnetic, dielectric, and con-
ductive behavior of materials at radio and microwave frequencies in terms of
the atomic constitution and structure of matter.

An important aspect of this work is the beginning of a materials measure-
ment center to provide information on materials which is not readily avail-
able elsewhere. During the past year emphasis was upon the establishment
of a group which is specifically concerned with studies of magnetic materials.

A waveguide cavity, containing a crystal specimen, is placed between the poles
of a magnet in studies of magnetic resonance. The objective is the establish-
ment of standards and measurement techniques, based on a better understand-
ing of the interaction of electromagnetic waves with matter (page 48).

In the measurement of magnetization of materials a significant contribution
was the development- of an absolute technique for calibrating vibrating
sample magnetometers. The new technique greatly improves the accuracy
of determining spontaneous magnetization, a significant parameter in funda-
mental magnetic investigations, as well as a figure of merit in many micro-
wave material engineering problems.

An improved Maxwell bridge was completed to measure resistance as low
as 10~7 ohms, and inductance as low as 10"11 henrys, at frequencies from
1 to 100 kc/s. It is unique in that the sample of material can be inserted
without opening the unknown arm of the bridge. Contact resistance is thus
eliminated and low permeability measurements can be made with greater
accuracy than previously possible.

A study of the dynamic magnetoelastic properties of several ferrites resulted
in a new technique for analyzing the mechanisms responsible for magneti-
zation in a material. This method is based on the fact that domain-rotation
and domain-wall phenomena are apparently separated when magnetostrictive

measurements are made on selected ferrites subjected to mechanical shock.
The dependence of Young's modulus on a static magnetic field was reported
for the first time.

The accuracy of the rf permeameter was increased through the develop-
ment of exact working equations. This has improved measurements on
extremely low loss materials by at least an order of magnitude.

Magnetic resonance studies were initiated to determine the magnetic
energy levels, relaxation times, and transition probabilities of paramagnetic
and antiferromagnetic crystals. This will provide information on internal
crystalline fields and exchange interaction. An investigation on the effect
of impurities on the spontaneous magnetization of nickel was also instituted.

Electronic Calibration Center, The Electronic Calibration Center
provides an extensive calibration service for various agencies in the Depart-
ment of Defense as well as for scores of industrial laboratories. There is a
continued effort to improve the instrumentation and thus increase the
efficiency, accuracy, and scope of the Center's calibration services.

The method developed for the accurate calibration of inductive voltage
dividers — using a transformer capacitance bridge — has surpassed all ex-
pectations of accuracy. By a conservative estimate, this method of measure-
ment is accurate to within 0.2 parts per million of input. Calibration serv-
ices for inductive voltage dividers were established for several values of ratio
at an input voltage of 100 volts and a frequency of 100 c/s.

This year the Center had the opportunity to observe a group of saturated
standard cells soon after the group had been measured by the NBS labora-
tories in Washington. Results indicate that agreement between the two
laboratories is within 0.6 millionth of a volt, or well within the estimated
limits of accuracy.

A modification of the rf voltmeter calibration consoles, which will improve
their accuracy by a factor of 10 for frequencies up to 100 Mc/s, was nearly
completed. These consoles cover the range of 30 kc/s to 100 Mc/s from
0.2 to 500 v, and the frequencies of 300 and 400 Mc/s from 0.2 to 100 v.

An attenuation calibration console which will permit very accurate measure-
ment at 1, 10, 30, 60, 100, and 300 Mc/s was essentially completed. Its
total dynamic range is 140 db, and it is estimated to be accurate within
0.07 db at the upper limit. Some of the more precise laboratory standards
may be calibrated over a range of 0 to 60 db within an accuracy of
± (0.002 db + 0.01 percent of the total attenuation in db) .

A technique, accurate to within one percent, was developed and services
provided for the calibration of dry calorimeters for measurement of micro-
wave power over a range of 10 to 100 milliwatts and a frequency range of
8.2 to 12.4 kilomegacycles.

A new high-temperature oven was designed and constructed, for the micro-
wave noise measurement system, with a control circuit that maintains the
temperature of the oven at a given point to 1 degree at approximately
1,000 °C. The hot-body noise standard was redesignated so that its operation
is more reliable and its structure is easier to analyze.

2.1.5. HEAT

Heat measurements, standards, and related research play a most important
role in modern science and technology. The Bureau discharges important
responsibilities in these areas through the maintenance of the National
standards for heat measurements. Internationally agreed upon temperature
standards are maintained to assure a common scale upon which all tem-
perature measurements are based. A strong research program aims to keep
these standards adequate for the expanding National needs. In addition,
supporting research on the physical properties of solids and gases at both
low and high temperatures includes studies in low temperature physics, in
statistical thermodynamics, in high-temperature processes, in high-pressure
thermodynamics, and in various aspects of plasma physics.

During the year significant progress was made in the generation and
accurate measurement of high temperatures and pressures. An acoustical
interferometric method was used successfully to measure very low absolute
temperatures in the liquid helium range. The investigation of the thermo-
dynamic properties of light-element substances important in rocket propulsion
was continued. In addition, advances were made in long-range experi-
mental and theoretical programs devoted to characterizing and predicting
the properties of hot gases and highly ionized gases (plasmas) .

High-Temperature Thermocouple Furnace. A tantalum-tube fur-
nace has been designed and constructed to study the high-temperature
properties of refractory metal and rare metal thermocouple materials. The
furnace has been operated at temperatures up to 2,000 °C and, with minor
modifications, temperatures up to 2,200 °C are anticipated. The heating
element in the furnace is a tantalum tube heated through its own resistance.
Thermocouples to be calibrated in the furnace are placed inside of the tan-
talum tube and are free from insulating and protection tubes. Blackbody
temperatures at the measuring junctions of the thermocouples are determined
by a calibrated commercial optical pyrometer with a modified optical sys-
tem. Thermocouples can be calibrated in a high-purity helium atmosphere
or a moderately high vacuum.

Electrical power to the furnace is regulated by a saturable core reactor.
Stable furnace temperatures are maintained through the use of an automatic
controlling unit which receives a feed-back voltage from the furnace trans-
former winding. At 1,500 °C the maximum temperature fluctuations in-
dicated by a thermocouple over a 10-min period were less than 1 deg C.
A limited amount of data have been obtained on tungsten-rhenium and ir-
idium-iridium-rhodium type thermocouples. Other thermocouple combina-
tions to be investigated include tungsten-tungsten 26 percent rhenium, tung-
sten-iridium, and tantalum-tungsten 26 percent rhenium (see p. 33).

Photoelectric Pyrometer. Above the freezing point of gold, 1,063
°C, the disappearing filament optical pyrometer is used for the realization
of the International Practical Temperature Scale ( IPTS ) . The precision of
brightness temperature determinations with this instrument is limited by the

contrast sensitivity of the human eye. This limitation, however, can be re-
duced significantly by using a physical detector rather than the eye to make
brightness matches.

During the past few years NBS has been developing a photoelectric optical
pyrometer which uses a photomultiplier tube rather than the eye as a de-
tector. This instrument, now completed, has a precision at 1,063 °C of
0.02 deg C when a time constant of 1 2/3 seconds and a target size of 0.2
mm by 0.6 mm are used. In comparison, the precision of the NBS visual
optical pyrometer at 1,063 °C is about 0.3 deg C. Moreover, the higher
precision of the photoelectric pyrometer has been achieved with a spectral
passband of only 100 A, or about 1/4 that of the visual pyrometer. This
is important because the mean effective wavelengths of the pyrometer can

As part of an effort to extend the range and accuracy of temperature measure-
ments, the thermoelectric properties of high-temperature thermocouples such
as tungsten-rhenium and tungsten-iridium are studied in this experimental
tantalum tube furnace. Operating temperatures of 2,000 °C and higher are
obtained (page 51).

be determined more accurately. The increased precision and the more ac-
curate mean effective wavelengths are expected to improve the accuracy
with which the IPTS can be realized.

The long-term stability of the photoelectric pyrometer is now being inves-
tigated in order to determine how often the instrument will have to be cali-
brated. The heart of an optical pyrometer is the pyrometer lamp. This
lamp serves as a reference standard for the pyrometer much as an electrical
standard cell does for a potentiometer. Therefore, the stabilities of various
types of pyrometer lamps are being determined. Preliminary results show
that some lamps, previously considered excellent, change by an amount
equivalent to 0.5 deg C in 150 hours of use at the gold point. These in-
vestigations are expected to result in recommended procedures for the
optimum design, aging and use of pyrometer lamps.

Specific Heat of Diamond at High Temperatures. Accurate
measurements of the specific heat of gem diamonds between 273 and 1,100
°K have recently been completed. These measurements will be used for
comparison with values calculated theoretically from lattice dynamics over
a wide temperature range. Such investigation should lead to a better
understanding of the covalent bonds important to chemistry. It will also be
possible to evaluate the energy contribution from nonharmonic vibrations in
the diamond crystal. These assume greater importance with increasing
temperature.

The high accuracy of this research will permit extrapolation of the meas-
ured specific-heat values to higher temperatures with less uncertainty than
has been possible in the past. Other thermodynamic properties of diamond
derived from this work permit examination of the temperature and pressure
relationships which exist when diamond is formed from graphite.

Thermodynamic Properties of Light-Element Compounds.
Under the sponsorship of the Department of Defense, the Bureau is contin-
uing its comprehensive interdisciplinary program of thermodynamic research
on simple light-element substances which are important in rocket propulsion.
The compounds being specially investigated are those of lithium, beryllium,
aluminum, and zirconium with hydrogen, oxygen, fluorine, and chlorine, as
these compounds are potential fuel components, fuel oxidizers, and combus-
tion products. During the past year the program extended its emphasis to
include compounds of "mixed" type (such as intermetallic compounds,
double fluorides of two metals, and oxyfluorides) whose use may lead to
substantial gains in propulsion efficiency.

Though propulsion efficiency depends on the simultaneous operation of all
the thermodynamic properties being separately investigated in the program,
the most critical property is the heat of formation. The Bureau has re-
cently contributed reliable values for this property for several important
substances. A series of measurements established accurately the heats of
formation of three alkali-metal perchlorates and ammonium perchl orate, the
last substance in particular being a widely used fuel oxidizer. Nitronium
perchlorate may have similar application, and measurements on it are under-

Photoelectric pyrometer, which eliminates the variability due to human error
in strip lamp and optical pyrometer calibrations, has greatly increased the pre-
cision of temperature measurements above 1,063 °C. A phototube, rather than
the human eye, is used to make brightness matches between the internal lamp
and the source (page 51).

way. Another recent achievement was the successful development of a
method for the complete combustion in a bomb calorimeter of a metal in
fluorine when the product is relatively non-volatile. This work gave a
heat of formation of aluminum fluoride which closely substantiates a value
which had been determined by a less direct method, and raises this property
to 15 percent above that accepted a few years ago. Similar measurements
are being initiated to resolve a large discrepancy in the heat of formation
of another important combustion product, beryllium fluoride.

The development and testing of new apparatus to measure other proper-
ties is nearing completion. In one of these, an exploding-wire device to
study systems thermodynamically up to 6,000 °K and 100 atmospheres
pressure, a major goal was achieved. The accuracy of measuring the total
electrical energy entering an exploding wire during a few microseconds was
verified when two independent types of comparison with the heat energy pro-
duced had an uncertainty of less than 2 percent. This agreement is con-
sidered very good for such short time intervals. The method of calibration
employs a fixed resistance element as a calorimeter. The element is inserted
in the discharge circuit in place of the exploding wire, and the calorimetric
heating of the element is measured with high accuracy. This is used as
a reference for comparing the ohmic heating and the electrical energy
obtained from the measured current through the element and the measured
voltage across the element.

A high-speed shutter has been developed in order to permit photographic
observation of any portion of the electrical wire explosion. The shutter
consists of two parts: a fast-opening part and a fast-closing part. Using
Edgerton's method, the fast-closing action is obtained from the blackening
of a window by exploding a series of parallel lead wires. The fast-opening
of the shutter consists of a piece of aluminum foil (approximately 1 in. x
3 in.) placed directly in front of the camera lens so that no light may pass
into the camera. The opening action is obtained when a capacitor, charged
to high voltage, is suddenly discharged through the foil. During the dis-
charge the magnetic forces set up by the passage of current cause the edges
of the foil to roll inward toward its center line, thus allowing light to pass
into the camera. Experiments have shown that the shutter is 75 percent open
in about 60-80 microseconds. The shutter aperture may be made larger
or smaller by changing the foil area and adjusting the electrical energy
input to the foil.

Laboratory Measurements of Interstellar Radio Spectra. Besides
the well-known hydrogen line at 21 cm wavelength, the spectra of extraterres-
trial radio sources may contain sharp lines characteristic of other atoms,
ions, and small molecules. The detection and study of such line spectra
would add considerably to present information on interstellar gas clouds
and, perhaps, planetary atmospheres. Among the most likely producers
of detectable radio line spectra are the light diatomic hydrides OH and CH;
somewhat le'ss likely sources are the heavier hydrides SH, SiH, and ScH.
Very small concentrations of these hydrides should be detectable; in inter-
stellar gas, concentrations as low as 10~6 molecules/cm3 may be sufficient, as
compared to the 10~2 hydrogen atoms/cm3 required for detection of the 21-cm
line.

High sensitivity in radio telescopes is achieved by reducing the bandwidth
of the receiver; therefore, only with precise foreknowledge of the line fre-
quencies is an astronomical search for the radio spectra of these molecules
feasible. To secure precise measurements of these frequencies, a research
program in free radical microwave spectroscopy has been started. Since
conventional methods are insensitive at the low frequencies of these molecular
transitions, the paramagnetic resonance method is being used instead. This
involves the application of a strong magnetic field to the radical vapor,
which shifts the low-frequency spectra to a conveniently high microwave
range, where they may be measured with optimum sensitivity.

The first diatomic hydride investigated by the paramagnetic resonance
method was the OH radical. Results of this experiment include the fre-
quencies of the two strong spectral lines by which OH may be identified in
interstellar gas; the frequencies are 1665.32 and 1667.36 Mc/s, with an
uncertainty of 0.10 Mc/s. Success in observing these spectral lines has
so far, apparently, been confined to the laboratory; extraterrestrial observa-
tions have yet to be reported. Preparations are being made for similar
experiments on CH and SH radicals.

Low Temperature Thermometry. The Bureau is pursuing an ac-
tive program to provide a temperature scale and thermometer calibration
services in the range 1.5 to 20 °K. The efforts and accomplishments fall
into three main categories: absolute thermometry based upon the velocity
of sound in helium gas, secondary thermometry involving principally studies
of the behavior of germanium resistors, and helium-4 vapor-pressure measure-
ments (see p. 144) .

Acoustical Interferometer. An acoustical interferometer has been
constructed and used, with helium gas as the thermometric fluid, to measure
temperatures near 4.2 and 2.1 °K. Such an interferometer provides a
means of absolute temperature measurement, and may be used as an alterna-
tive to the gas thermometer. When values of temperature derived with this
instrument were compared with the accepted values associated with liquid
helium-4 vapor pressures, differences of about 10 and 7 millidegrees re-
spectively were found. This result is preliminary, and work is continuing.

Resistance Thermometers. Carbon resistors and impurity-doped
germanium resistors have been investigated for use as precision secondary
thermometers in the liquid helium temperature region. Several germanium
resistors have been thermally cycled from 300 to 4.2 °K and their resistances
have been found to be reproducible within % millidegree when temperatures
were derived from a vapor pressure thermometer whose tubing is jacketed
through most of the liquid helium. Preliminary calibrations of the resistors
have been made from 4.21 to 2.16 °K at every 0.1 °K. The estimated
standard deviations of the data for two of the resistors were ^ 1 milli-
degree; and for the third resistor, ^ 3.3 millidegrees.

Vapor Pressure Method. The reproducibilities of helium vapor-pres-
sure thermometers have been investigated in conjunction with a "constant
temperature" liquid helium bath from 4.2 to 1.8 °K. Surface temperature
gradients have been found to exist in liquid helium baths contained in
15- and 25-liter metallic storage dewars. The gradient was about one half
of a millidegree at 4.2 °K but increased to several millidegrees for bath
temperatures slightly greater than the A point. A hydrostatic head correc-
tion has been neither necessary nor applicable in the determination of vapor
pressures or temperatures for the bulk liquid helium. However, the surface
temperature gradient can produce erroneous vapor-pressure measurements
for the bulk liquid helium unless precautions are taken to isolate the tube
(which passes through the surface to the vapor pressure bulb) from the liquid
helium surface. It has also been observed, in helium II, that large discrep-
ancies can exist between surface vapor pressures and those pressures meas-
sured by a vapor pressure thermometer. This has been attributed to helium
film flow in the vapor pressure thermometer. In this case also the design of
the thermometer can be modified to reduce the helium film flow.

Pressure Transducer for PVT Measurements. Precise pressure-
volume-temperature measurements on corrosive gases are dependent on a
sensitive yet rugged pressure transducer. A prototype which fulfills the
requirements was developed and thoroughly tested. The transducer is a null-

type instrument and employs a stretched diaphragm, 0.001 in. thick and
1 in. in diameter. A small pressure unbalance displaces the diaphragm and
changes the capacitance between the diaphragm and an electrically insulated
plate spaced 0.001 in. apart (for AP=10 microns of mercury, the average
displacement = 10~6 in. and AC = 0.014 pf ) . Spherical concave backing
surfaces support the diaphragm when excessive pressures are applied and
prevent the stresses within the diaphragm from exceeding the elastic limit.
Over a temperature range from 25 to 200 °C and at pressures up to
250 atm, an overload of 300 psi, applied for a period of one day, results
in an uncertainty in the pressure of, at most, one millimeter of mercury.

Transport Properties of Air. A 6-year study of the transport prop-
erties of air at elevated temperatures has been completed. This project was
carried out under sponsorship of the Ballistic Missile Division of the Air
Research and Development Command, U.S. Air Force, and had as its goal
the investigation of the transport by diffusion of the heat energy of chemical
binding. A significant effect discovered during the study is the existence of
Prandtl numbers reaching values of more than unity in the nitrogen dis-

Absolute temperature measurement in terms of the speed of sound in helium
gas at liquid helium temperatures is one phase of the program to provide a
temperature scale and thermometer calibrations in the range 1.5 to 20 °K
(page 56).

616114 O— 61 -5 57

sociation region. Another effect discovered is the large coefficient of thermal
diffusion tending to separate nitrogen from the oxygen when temperature
differences straddling the nitrogen dissociation region are present. The
results of the study, based on collision integrals computed from the latest
critically evaluated data on intermolecular forces in air, will be reported in
the form of a table of viscosity, thermal conductivity, thermal diffusion, and
diffusion coefficients at temperatures of 1,000 to 10,000 °K and of logarithm
of pressure in atmospheres from 10s to 103 times normal density.

International Cooperative Activities. In March, 1961, representa-
tives of the national laboratories of Australia, Canada, The Netherlands,
United Kingdom, U.S.S.R., United States, and West Germany, met at the
NBS to devise means for reaching international agreement on a temperature
scale between 10 and 90 °K. As a first step toward this goal, arrange-
ments were worked out for comparing the scales now in use through circula-
tion of a group of standard platinum resistance thermometers for calibration
by each national laboratory. Such a group of thermometers was obtained
and calibrated at the NBS. These thermometers have now been sent to the
United Kingdom for calibration at the National Physical Laboratory.

Temperature Symposium. During the last week of March 1961,
Columbus, Ohio was the site of the Fourth Symposium on Temperature, Its
Measurement and Control in Science and Industry. The Symposium, which
was jointly sponsored by the American Institute of Physics, the Instrument
Society of America, and the National Bureau of Standards, attracted nearly
one thousand registrants, including many from abroad. The Bureau con-
tributed to the planning and success of the Symposium through the efforts
of Mr. W. A. Wildhack, General Chairman, and Dr. C. M. Herzfeld, Program
Chairman. Dr. A. V. Astin, NBS Director, opened the 5-day session with
introductory remarks, following which a total of twenty-six papers were given
throughout the week by NBS scientists, from both the Washington and
Boulder Laboratories.

2.1.6. ATOMIC PHYSICS

In addition to the basic programs in wavelength standards, spectroscopy,
solid state physics, interactions of the free electron and atomic constants
which are necessary to provide the foundation for technological progress, the
Bureau has strengthened its activities in laboratory astrophysics. The pro-
grams in infrared spectroscopy are undergoing reorientation toward wave-
length standards in the far infrared, the application of infrared techniques
to solid state studies, and increased emphasis on high resolution instrumenta-
tion. Two data centers have been established for the collection, indexing,
critical evaluation, and dissemination of bibliographies and critical values
in the fields of transition probabilities and collision cross sections.

Laboratory Astrophysics.

Transition Probabilities. Under the sponsorship of the Office of Naval
Research and the Advanced Research Projects Agency, a data center was

The spectral intensities of over 39,000 lines for 70 elements were determined
and published in tabular form. The new tables provide spectrochemists with
much-needed quantitative intensity values for those elements most commonly
encountered in their analyses (page 59).

established to gather and index all published information on atomic transi-
tion probabilities. An exhaustive survey was made of the literature, and a
primary reference file of approximately 600 references was catalogued.
Selected bibliographies and tables of available data are now in preparation.

A wall-stabilized high-current arc source was constructed and used to study
transition probabilities of atomic hydrogen and oxygen. This apparatus
will also be used to measure transition probabilities of a large number of
other elements. A study of the hydrogen line profiles indicates that a
measurement of these profiles can be used to calculate a temperature for the
arc plasma that is reliable to about ± 2 percent.

A set of tables containing spectral intensities for 39,000 lines of 70 ele-
ments, as observed in a copper matrix in a d-c arc, was completed and
published. Studies of the intensity data indicate that they may be con-
verted to approximate transition probabilities. These data are not of the
precision obtainable by the methods previously mentioned, but the vast
number of approximate values available will be useful in many areas.

Atomic Energy Levels. Research continues on the very complex spec-
tra of the rare earth elements. New computer and automation techniques
were applied to these spectra with considerable success. A number of
energy levels were found in the spectrum of cerium; none had previously

been known in this spectrum. Substantial progress was made in the an-
alyses of the spectra of thorium, praseodymium, ytterbium, bromine, and
dysprosium.

The work on spectrum analysis has been aided greatly by theoretical
prediction of the positions of energy levels in low, even configurations.
Extensive computations were made on the first spectra of hafnium and tan-
talum and the third spectrum of praseodymium.

Collision Cross Sections. The measurement and calculation of low-
energy collision cross sections was continued, with efforts concentrated on
construction of apparatus and refinement of instrumentation. Special em-
phasis is being given to the development of sources of low-energy mono-
energetic electron beams for use in measurement of elastic and inelastic
collision cross sections.

Theoretical studies of the use of refined wave functions in the calculation
of electron scattering and photodetachment are continuing. Several high-
vacuum instruments for measuring electron collision cross sections are
essentially completed.

The photodetachment of electrons from carbon negative ions was ob-
served and studied. Careful measurements of detachment near threshold
for the process lead to a value for the electron affinity of carbon of 1.25 ± .03
ev (28.6 kcal). Values of upper limits for the photodetachment cross sec-
tions of several of the important atmospheric negative ions were determined
at a wavelength of 4000 A.

Studies involving very precise measurements of the dependence of drift
velocities of argon ions in the parent gas on the electric field have been com-
pleted. The results raise serious doubts concerning the validity of current
theory describing the motions of charged particles in gases.

A data center was established to gather and index all published informa-
tion on collision cross sections. A complete file of reprints of papers on
low-energy electron cross sections was collected. A code has been worked
out for tabulating the large number (over 800) of references on punch cards.
About one-half the papers have been coded. The data collection will be
extended to cover other atomic cross sections.

Standard Wavelengths. The wavelength of the resonant line emitted
by an atomic beam of mercury 198 was measured relative to the standard
wavelength emitted by the krypton-86 isotope, which was adopted in 1960
as the new international standard of length. The line emitted by the
mercury-198 beam is nearly ten times as sharp as the krypton standard
line.

Several atomic beam devices are under development that show promise of
producing wavelength standards potentially superior to the present inter-
national standard (see 2.1.1., p. 21) .

infrared Spectroscopy of Gases. During the past year a great deal
of materials research was conducted on the infrared spectra and vibration-
rotation energy levels of various compounds. This research was sponsored

by the Atomic Energy Commission. Work was completed on the analysis of
the infrared spectrum of acetylene. In this work, the values of a number
of vibrational and rotational constants for C2H2 were very accurately estab-
lished. Similar studies on the deuterated acetylenes, C2HD and C2D2, were
initiated. When the constants for all three of these molecules have been
obtained, it will be possible to anive at very accurate values for the bond
lengths and other structural parameters for acetylene. This work is of great
importance as it offers the best way of obtaining these parameters for a
compound which is considered by chemists to be a classic example of a triple
carbon-carbon bond.

Infrared Spectroscopy of Solids. Work has been initiated on fun-
damental studies of the infrared spectra of solids and the effects of crystal
structure, temperature, and purity on these spectra. Because of the com-
plexity of the problem and of the state of knowledge of intermolecular forces
and the manner in which they affect the infrared spectra of solids, much
fundamental work is needed in this field. A study of CO has shown that
because of interactions between neighboring molecules in the solid, the ab-
sorption frequency of the most abundant isotopic species is shifted slightly,
while that of the isotopic species present in smaller abundance is unaffected.

Solid-State Physics. Pure rutile (Ti02), has a large, low-frequency
dielectric constant (ec = 173 and ea — ^9 at room temperature) . The Bureau's

Studies of the photodetachment of electrons from negative atomic and molecu-
lar ions provide a better understanding of the ionized layers of the upper
atmosphere (page 60).

work reconfirmed these values and explained disparities in previously pub-
lished data. Because of the close relation between rutile and several ferro-
electric titanates, the temperature dependence of the dielectric constant was
studied between 1.6 and 1,060 °K. In both the c- and a-directions, the di-
electric constant changes only by a factor of 2 or 3 and no anomalies occur.
Lorentz corrections, polarizabilities, and effective charges were calculated.
It appears that the polarizabilities in rutile are within 10 percent of the
critical values for the ferroelectric catastrophe over the entire temperature
range.

A considerable amount of data was taken on the electrical, magnetic, and
optical properties of rutile. There is now strong evidence that one of the
major defects in reduced rutile is an interstitial Ti-ion.

Titanium sesquioxide with excess oxygen has been shown to be a /?-type
semiconductor below the transition point at 480 °K, while the conduction
is metallic in character above that temperature.

A theoretical study was made of the electrical conductivity, Hall coefficient,
and thermoelectric power of decomposing oxides as a function of the oxygen
vapor pressure at high temperatures. As a result of this analysis, methods
were selected to derive intrinsic parameters such as energy gap and effective
masses from measurements of the pressure dependence of the transport
properties.

Investigations of electron spin resonance absorption in oxides were ini-
tiated in collaboration with the mineral products laboratory (see p. 84).

Electron Scattering, A single scattering experiment tied together
three previously unrelated topics (diffraction, characteristic-loss scattering,
and plural scattering theory) and provided new insight into the theoretical
model of electron scattering in solids. The measurements represent the first
detailed experimental example of a theory of electron scattering proposed
in 1921 by Wentzel, and support a model of inelastic scattering proposed by
U. Fano of NBS in 1956. They show that electrons elastically scattering
from aluminum foils have the same angular distribution for all foil thick-
nesses, indicating that the elastic scattering process is a type of diffraction.
Moreover, the inelastically scattered electrons undergo repeated collisions
of a type involving long-range interactions with the electrons of the target
material.

Culminating several years of research effort, the first time-resolved photo-
graphs of a pulsed cadmium atomic beam (density ^lO11 particles/cm3,
equivalent to ~10-5 mm Hg pressure) was achieved by means of an electron-
optical stroboscopic method. The purpose of this work, which is sponsored
by the Office of Naval Research, is to develop a method to measure the vector-
velocity distributions of gas molecules reflected from solid surfaces and to
use these data to compute the coefficients of thermal accommodation and
viscous slip. Low-density collimated pulses of gas atoms (or molecules),
moving rectilinearly in a narrow velocity range (around 300 msec), are
photographed by an electron optical schlieren technique. The electron

An electron scattering experiment, utilizing an improved electron filter lens,
provided new insight into the theoretical model of electron scattering in solids
(page 62).

beam is pulsed stroboscopically, thus providing a picture of the instantaneous
distribution of atoms at a known time after the formation of the atomic
beam pulse. The time delay between the atomic beam pulse and the electron
beam pulse is varied so that the velocity distribution in the atomic beam may
be studied.

Atomic Constants, Plans were developed and equipment is being as-
sembled for a new precision measurement of the cyclotron frequency of the
electron. This experiment will provide a sensitive check on the predictions
of quantum electrodynamics concerning the anomalous magnetic moment
of the electron.

Atomic Standards of Frequency. The construction of several proto-
type frequency standards based on hyperfine resonances in rubidium vapor
was completed, and the performance of the standards is being evaluated by
systematically intercomparing them with the primary standards at the
Bureau's Boulder Laboratories. Plans to use a miniaturized version of the
clock for a test of relativity theory were discontinued as a result of measure-
ments made elsewhere using the newly discovered Mossbauer effect.

A rubidium vapor maser with an oscillation parameter of about 0.6 was
developed. Further improvements being attempted at Columbia University
are expected to achieve unity oscillation.

2.1.7. RADIATION PHYSICS

The increasing application of atomic and nuclear technology to industrial,
medical, and defense activities has resulted in an expansion of the demands
placed upon radiation research. Industrial uses of radiation have brought
about a growing need for improved standards and dosimetry at high dose
levels and high energies. Medical users increasingly turn to higher ener-
gies and call for improved determination of both source output and absorbed
dose. Research workers interested in the effects of radiation on various
materials have need for more information in their field. The Bureau has
attempted to meet these increasing demands with its radiation research
program.

The research of the Bureau is directed toward obtaining basic experi-
mental and theoretical data concerning the interactions of radiation with
nuclei, atoms, and molecules, as well as with bulk matter; the investigation,
development, and improvement of radiation sources and standards; and
the development of improved techniques and instruments for the detection
and measurement of these radiations.

Radioactivity Standards, A manganese 54 point-source standard, a
scandium 46 gamma-ray solution standard, an iron 55 electron-capturing
nuclide standard, and a promethium 147 beta-ray standard were developed
during the year. Using the NBS internal compensated gas counters, the
half -life of carbon 14 has been redetermined as 5,760 ±50 years, where the
indicated uncertainty denotes an estimated overall probable error of the
result.

The low-level counting facilities have been completed and the "white" room
which was designed to exclude 99.9 percent of all dust particles greater in
size than 1 micron has so far revealed none larger than 0.1 micron. This
facility is for studying methods of measuring the amounts of radionuclides
present at very low concentrations and in making international intercompari-
sons of radioactive samples at these concentrations. The program has also
included an examination of low levels of contamination of materials and
reagent chemicals by any radionuclide.

Radiation Theory, To provide information on the basic processes of
radiation production, on the characteristics of the radiations, and on their
absorption by, or other interactions with, matter the Bureau maintains a
broad program in radiation theory. Work on photon and neutron penetra-
tion, together with application to structure shielding against radiations from
nuclear weapons, has been partially supported by the Office of Civil and
Defense Mobilization and the Defense Atomic Support Agency. Work on
charged particle penetration and elementary cross sections has been partially
supported by the Office of Naval Research.

Computer Programs. Major and sophisticated computer programs
have been developed for calculations of electron and gamma-ray penetration.
The Monte Carlo program of calculating the multiple scattering of charged
particles has been so refined that it is now possible to analyze the differences

"White" room constructed for use as a low-level radioactivity laboratory and
a sample-preparation room. This facility is used in studying methods for
measuring very low concentrations of radionuclides and for international com-
parisons of radioactive samples at these concentrations (page 64).

between electrons and positrons in regard to phenomena such as back-
scattering or transmission by thick foils. The Monte Carlo program has
also been applied to the analysis of proton range and stopping power ex-
periments, with the aim of extracting the best value of the "mean excitation
potential," which is a key parameter in the stopping power formula. A
program for calculating neutron penetration distributions by moment methods
has been nearly completed. This program should make it possible to study
the physics of neutron penetration in detail, and should also make possible
a much wider variety of deep penetration data than has ever been available
before. Exploratory applications of this program are underway.

A nuclear optical model code was written to predict neutron elastic
scattering cross sections. This code includes an estimate of the compound
elastic scattering in addition to the shape elastic scattering which comes
directly from the nuclear optical model. A report was prepared on the elastic
scattering cross sections for calcium.

Data Collection. Data collection activity during the past year included
a tabulation of X-ray spectra in uniformly contaminated media. This tabu-
lation was also used for a detailed analysis of the errors that arise in the
numerical solution of the X-ray degradation equation.

Results of the proton Monte Carlo work at 340 Mev and 660 Mev on range
and range straggling has been analyzed and an estimate has been obtained
of the small systematic error resulting from the particular Monte Carlo model
that has been used. The sampled data was also used to obtain an estimate
of the statistical distribution of the difference between path-length and depth
of penetration for high-energy protons.

Civil-Defense Shielding Problems. Considerable work has been done
toward the theoretical solution of shielding problems associated with the
"fallout" of fission products from nuclear explosions. A monograph, "Struc-
ture Shielding Against Fallout Radiation from Nuclear Weapons," has been
virtually completed. Work has been started to develop engineering data
applicable to initial radiations, in analogy to the work completed for fallout
radiations. Some work on Monte Carlo calculations for the analysis of simple
structure geometries has continued but the emphasis has shifted to more com-
plex geometries than slabs. The computer programs for calculating gamma-
ray penetration have been revised and made more general, in order to make
possible their use by other investigators ; their use to produce more detailed
information about flux angular distributions; and to make possible reliable
calculations at high energies ( < 10 Mev) .

Linear Electron Accelerator, The Bureau has been engaged for some
time in the design of a new linear electron accelerator to be housed in its
new Gaithersburg facility. This accelerator will produce a 100-Mev electron
beam with 40 kilowatts in the beam. The design of the accelerator has been
completed and the machine is now under construction. It is expected to
be completed in November 1962. During the past year considerable effort
has been devoted to completing the design of the laboratory in which the
accelerator will be housed and the design of a beam-handling and analysis
system. Since the accelerator will provide a beam with an energy spread of
less than 2 percent, it will be possible to utilize a large fraction of the electron
beam even after energy analysis by the beam-handling and analysis system
of magnets, which will provide energy resolutions as small as 0.05 percent.

The magneto-optical properties of systems of magnets were studied dur-
ing the course of the design of the linac beam-handling system. A con-
venient matrix method was developed and applied to combine by a first-
order procedure analyzing and quadrupole magnets in order to predict the
focusing and dispersing properties of combinations of magnets. This method

has now been published in a paper that demonstrates the general applicability
of the matrix techniques to general deflection magnets. The method has also
been used to predict by a second-order theory the properties of precision
particle spectrometers. It has now been demonstrated that an energy
resolution better than 0.05 percent is obtainable for reasonable target sizes
with particles having momenta up to 250 Mev/C and with solid angles in
the range from 0.005 to 0.01 steradians.

High-Energy Radiation. Research utilizing the betatron and synchro-
tron included two studies partially supported by the Atomic Energy Com-
mission. One of these dealt with the measurement of neutral meson produc-
tion for carbon, aluminum, copper, cadmium, and lead. The other involved
a measurement of the photoneutron yield and photon-scattering cross sec-
tions for the highly deformed nuclei of holmium and erbium.

Angular distributions of neutral mesons photoproduced by 170 Mev
bremsstrahlung from the synchrotron have been measured. The experi-
mental distributions have been compared to Monte Carlo predictions and
thereby have provided a measurement of the root mean square radii of
nucleon center distributions having an estimated uncertainty of three per-
cent. These results are about 0.2 fermi lower than the electron scattering
measurements of the rms radii of charge distributions obtained at Stanford
University. About one-half of this difference is understandable on the basis
of the proton size. The remaining difference is approximately equal to the
present uncertainties in the experiment and, therefore, may or may not be
real.

The observed X-ray scattering cross sections for holmium and erbium
were large compared to those calculated from the observed absorption
(photoneutron) cross sections by means of the optical theorem and the
dispersion relations. The absorption and scattering cross section are
consistent if it is assumed that these nuclei have a large intrinsic tensor
polarizability. The data also suggest that in the energy region between 10
and 23 Mev as much as 10 to 20 percent of the integrated absorption cross
section is not associated with the tensor polarizability.

A third nuclear physics program that was actively investigated during the
past year was the measurement of total nuclear cross sections. This work
has required the development and improvement of the energy resolution
of high-energy scintillation X-ray spectrometers. The best results were
provided by a sodium-iodide spectrometer with a resolution of 2.5 percent
at 17.6 Mev.

Total nuclear absorption cross sections are being measured with this
spectrometer by examining the X-ray spectrum of 90 Mev bremsstrahlung
transmitted by long absorbers in a good-geometry experiment. The use of
the spectrometer combined with the high-intensity NBS synchrotron beam
made it possible to attenuate the primary X-rays by a factor of over 10,000
with a resulting enhancement in the transmitted spectrum of the effect of
small changes in the attenuation coefficient. The transmitted spectra show
clearly the giant resonance nuclear cross section, as well as fine structure

Model of the linear electron accelerator complex which will be built as part of
the NBS Radiation Physics Laboratory at Gaithersburg, Maryland. Dotted
line on the model indicates the ground level (page 66) .

in such absorbers as oxygen, carbon, and magnesium. The detailed evalu-
ation of the total nuclear and the total interaction cross sections in a wide
range of elements will be completed at the end of the present series of
experiments.

X- and Gamma-Ray Dosimetry. It is often assumed that cobalt 60
beams used for instrument calibration and radiation treatment contain only
gamma rays with energies of 1.17 and 1.33 Mev. Though it is widely
recognized that this assumption is not strictly valid because of the energy
degradation due to scattering, adequate experimental data was not previously
available to show the magnitude of the discrepancy. Therefore, experi-
ments were conducted to determine the intensity and energy of scattered
radiation from multicurie cobalt 60 sources and its variation with source
and collimator geometry.

Photographic Dosimetry. The Bureau has investigated the effects of
exposure of X-ray film to two successive types of radiation. The results
of this study show that the shapes of the density-versus-exposure curves re-
sulting from such dual exposures are essentially the same as those of the
curves resulting from the second exposure alone. This work, supported by
the Atomic Energy Commission, may lead to a better understanding of the
nature of the photographic latent image and may also be of some interest
in industrial and military applications of photographic dosimetry of X-
and gamma-radiation.

A simple film method of measuring X- and gamma-ray exposure doses in
the megaroentgen range has been developed at the Bureau with the support
of the Atomic Energy Commission. The method extends the exposure range
of commercial photographic film to 108 roentgens by employing a special
densitometric procedure. Since the print-out effect is utilized, no photo-
graphic processing of the film is required. A preliminary study has been
performed on extending the method to exposures lower than 10,000 roentgens
by a chemical treatment of the films prior to exposure. Results obtained
with one film type pre-treated with a ten-percent solution of sodium sulfite
showed some promise.

Chemical Dosimetry. An investigation has been made of the spectro-
photometric method of measuring the ferric ion yield in the ferrous sulfate
dosimeter. The ferric ion yield produced by ionizing radiation in a ferrous
sulfate dosimeter is usually determined by measuring the absorbance (op-
tical density) of the irradiated solution at a wavelength of 304 millimicrons.
By measuring the ferric ion yield at 224 m/x, instead of at 304 m/x, the sen-
sitivity of the spectrophotometric method can be approximately doubled and
the measuring range of the ferrous sulfate dosimeter using this method can
be extended to lower doses. The molar extinction coefficient at 224 m[x is
much less temperature dependent that at 304 mix, and shows also a smaller
dependence on sulfuric acid concentration than at 304 m/x. Values of the
ferric ion yield produced by Co60 gamma rays determined by measuring the
absorbance at 224 imx and 304 m/x agreed within experimental errors.

Irradiation Facilities, Through the cooperation of the Atomic Energy
Commission, a 50,000-curie high specific activity cobalt 60 source has been
obtained and installed at the bottom of a 12-foot-deep water pool. This
source gives a gamma-ray field of more than 107 roentgens per hour, thus
shortening required exposure times by a factor of about 25 over that for the
Bureau's 2,000 curie source. The new source will be utilized in dosimetric
studies involving high intensities, studies of the effects of intense gamma
radiation on various fluorocarbons, studies of gamma-ray production of radi-
cals at low temperature, and in an investigation of the relationship between
radiolysis and photolysis.

Nucleonic Instrumentation. In a program supported by the Atomic
Energy Commission a new type of pulse-height analyzer was developed and
placed in operation, in conjunction with the NBS 180-Mev synchrotron
This analyzer, designated as a "charge-storage analyzer" since it uses tempo-
rary electrostatic charge storage, is designed for use with pulsed accelerators.
Efficient operation of pulsed accelerators necessitates the analysis of many
pulses during the bursts of radiation. This often, involves dealing with
pulses separated in time by only a few microseconds and is accomplished
with this analyzer by temporarily storing the pulse-height information on
the face of a cathode-ray tube, followed by analysis of this stored data during
the relatively long dead intervals between bursts. This instrument is cur-
rently being used in nuclear absorption experiments that would be extremely
difficult to perform with conventional analyzers.

Neutron Physics. In research supported by the Atomic Energy Com-
mission and the Defense Atomic Support Agency, the Bureau is conducting
fundamental experiments on neutron penetration and neutron cross-sections.
This research provides information important for the protection of personnel.
for investigation of the interaction of radiation with materials, and for
understanding nuclear structure.

During the year a precision long counter was constructed, calibrated, and
compared with a similar instrument built at Hanford, Washington. Agree-
ment to within one percent was obtained.

The emission rate of the NBS standard neutron source (NBS-I) is being
redetermined by comparison with an antimony-beryllium neutron source in
an absolutely calibrated heavy-water manganous sulfate bath.

Measurements of elastic and inelastic scattering of 14 Mev neutrons by
time-of-flight from Ca40 and C12 were made. The results yield the ratio
of elastic to inelastic scattering and show an angular distribution of elastic
scattering in agreement with theory.

Radiation Protection and Radiation Standards and Units. Re-
search on the fundamental properties of radiation and on radiation standards
has placed the Bureau in a unique position to translate the latest information
in these fields into practical recommendations for radiation protection, quan-
tities and units. The Bureau has assisted in the dissemination of this infor-
mation by publishing as NBS handbooks the recommendations of the Na-
tional Committee on Radiation Protection and Measurements (NCRP) and
the International Commission on Radiological Units and Measurements
(ICRU). During the last year, five new handbooks have been published.
These include: Handbook 72, "Measurement of Neutron Flux and Spectra
for Physical and Biological Applications"; Handbook 73, "Protection
Against Radiations from Sealed Gamma Sources"; Handbook 75, "Measure-
ment of Absorbed Dose of Neutrons, and of Mixtures of Neutrons and Gamma

The Bureau's new 50,000-curie eobalt-60 source at the bottom of a 12-ft water
shielding pool, pictured with light from its own Cerenkov glow. The largest
single isotope source ever shipped by the AEC's Oak Ridge National Laboratory,
the new source greatly extends NBS capabilities in radiation calibration and
the investigation of the effects of radiation on the properties of materials. At
right, the geometry of the 50,000-curie source; the Co60 is contained in the
vertical metal tubes at the center (page 69).

Rays"; Handbook 76, "Medical X-ray Protection up to 3 Mev"; and Hand-
book 78, "Report of the International Commission on Radiological Units
and Measurements (ICRU) (1959)." Two handbooks — Handbook 79,
"Stopping Powers for Use with Cavity Chambers," and Handbook 80, "A
Manual on Radioactivity Procedures," — are presently in preparation. Staff
members have been very active in the work of the groups preparing these
handbooks, as well as in the work of the International Commission on Radio-
logical Protection (ICRP) and the recently established Federal Radiation
Council. These groups have formulated recommendations which represent
the latest scientific thinking in the broad area of radiation protection, quan-
tities and units.

International Standards. The Bureau has always been an active par-
ticipant in the activities of the International Bureau of Weights and Measures.
In October 1960 the General Conference of Weights and Measures approved
the extension of the work of the International Bureau into the area of ioniz-
ing radiation. A working group was set up to make recommendations on :
Immediate and long-range programs for this area, a laboratory design for
this work, laboratory equipment, and staffing. Members of the Bureau
staff involved in neutron measurements, radioactivity measurements, and
X- and gamma-ray measurements were invited to participate in this effort.
During a meeting held early in 1961 this group considered the entire program
and made recommendations. The staff of the International Bureau is now
in the process of implementing these recommendations.

The National Bureau of Standards has constructed and is presently cali-
brating transfer instruments for X- and gamma-ray measurements which will
be loaned to the International Bureau. These instruments will be calibrated
by the International Bureau as well as by many of the national laboratories
participating in the program. NBS has agreed to participate in one such
intercomparison during 1962.

The International Bureau is also arranging for exchanges of radionuclide
standards. NBS has participated in two such intercomparisons so far and
others are planned for the future.

2.2. CHEMISTRY AND PROPERTIES OF

MATERIALS

2.2.1. ANALYTICAL AND INORGANIC CHEMISTRY

As part of its program in the preparation, purification, and characteriza-
tion of materials, the Bureau develops and improves methods for the measure-
ment of the chemical properties, composition, and behavior of substances;
prepares standard reference materials of known composition or properties;
and makes accurate measurements of and collects data on chemical systems.
It also studies the properties of molecules and atoms in their relation to
chemical reactions, and provides technical and advisory services in specialized
areas of modern chemistry.

The special investigations pursued during the past year in inorganic,
analytical, and solution chemistry included studies of new as well as con-
ventional methods for chemical separations and analyses by spectrochemical
and other applied analytical processes. Substances of high purity were
prepared, criteria developed for measuring purity, and chemical constants
determined from pure materials.

New programs were initiated in the fields of crystal chemistry, coordina-
tion chemistry, and resonance spectroscopy.

Applied Analytical Research. The establishment of a program on
applied analytical research increased Bureau emphasis on instrumental
methods of analysis. The program, concerned with the development and
application of methods for analyzing and characterizing solids, liquids,
and gases, incorporates classical and instrumental methods using both
macro- and micro-techniques. New equipment obtained includes a high-
temperature linear-programmed gas chromatograph, infrared spectrometer,
mass spectrometer, automatic spectrometric-electrometric titrater, coulometric
titrater, high-sensitivity polarograph, Kjeldahl nitrogen-determination equip-
ment, and three types of micro-combustion apparatus: the Schoniger, the
semi-automatic Dumas for nitrogen micro-determinations and the semi-
automatic for carbon-hydrogen micro-determinations. In combination with
spectrometric, electroanalytical, and microchemical equipment previously
acquired, the Bureau is now well equipped to undertake a wide variety of
analytical instrumental investigations and analyses.

Chemical Preparations, An interdisciplinary program was conducted
on the redetermination of the atomic weights of chlorine and bromine.
For the chlorine study, isotopic concentrates obtained from Oak Ridge Na-
tional Laboratory were chemically purified and mixtures of known composi-
tion were prepared approximating the isotopic abundance ratio of normal
chlorine. Only analysis of stock solutions of the isotope concentrates,
also obtained from Oak Ridge National Laboratory, was involved in the
bromine preparation. From mass spectrometric determinations of the abso-
lute isotopic abundance ratio of these specimens the atomic weights of
chlorine and bromine were calculated.

Spectrochemical Advances. A critical investigation on methods for
the direct spectroscopic analysis of materials in solutions led to the develop-
ment of a gas-stabilized arc of high stability. This arc burns in a chamber
between a graphite anode and a water-cooled tungsten cathode. A flow of
argon within the chamber and a graphite ring orifice control its position.
For analyzing a sample, a capillary atomizer introduces the solution into the
arc at a steady rate. The elements in the vaporized sample are excited
to emit characteristic spectra with highly reproducible intensity. The arc
offers promise as a source for analyzing materials in solution and for study-
ing specific substances when a steady arc discharge is required.

In an investigation of the spectroscopic determination of gases in metals,
a self-contained portable apparatus for handling gases and exciting their
spectra was developed. The system is mounted on a metal table equipped

Arc source of high stability for exciting the spectra of materials in solution.
The source may be used for spectroscopic analysis or in other work where high
stability is required (page 72).

with a hydraulic lift and includes gas flow and pressure monitors as well
as a chamber for evolving gases from metals and for exciting their spectra.
The equipment may be moved and alined for use with different spectro-
graphs or spectrometers throughout the Bureau laboratory.

During an X-ray spectrometric study of surface condition effects on the
analysis of metals, the usual procedure of grinding a smooth surface on the
sample was found to cause serious errors in some cases where hard
and soft constituents are present in the metal. For example, if lead particles
were smeared over the surface in leaded steel, high readings for lead were
observed. Errors from this source were minimized by polishing the surfaces
with diamond dust.

616114 O — 61^

-6

Separation of Zirconium from Hafnium, Hafnium and zirconium,
ordinarily very difficult to distinguish chemically, can now be separated by
a single-step anion-exchange process. The separation for analysis is obtained
by using a strong quaternary-amine anion-exchange resin column with diluted
sulfuric acid as eluting solution. After separation of a mixture containing
approximately 100 mg each of hafnium and zirconium, a spectrochemical
examination showed only a few ppm (parts per million) cross contamination.

The method results from a systematic study of the elution behavior of a
variety of zirconium and hafnium complexes. It is better adapted to the
examination of hafnium-base alloys, because the hafnium is removed first in
the elution cycle, and less trouble is encountered in the hydrolysis of ions
of this element. In connection with this work, a procedure was developed
for the quantitative analysis of zirconium in hafnium metal, which is used
as a control-rod material in nuclear reactors.

Distillation Techniques Improved. Vapor-liquid chromatograms re-
sulting from successive fractions of precise laboratory distillations are gen-
erally more informative than the boiling temperatures or the refractive indices
because the progress in constituent separation is usually clearly shown. The
method is now being used routinely in the distillation laboratory with im-
proved results.

A new and better procedure for maintaining a constant flow of vapor to
the column of a laboratory still was developed. Control of this vapor velocity
is important because better separations of materials are obtained when the
velocity is low but constant. The method depends on the use of a thermistor
as a flowmeter to control the heat supplied to the vaporizer of the still. This
process has a number of advantages over the usual method of controlling
the heat supply by the changes in the vaporizer pressure.

A simple and reliable method was developed for cooling the reflux heads
of laboratory stills to low temperatures. With this technique, the low tem-
peratures may be maintained for long periods of time.

Accuracy for pH Standards Increased. Measurements of the acidity
or basicity of solutions, expressed on the pH scale, are of far-reaching im-
portance in chemical analysis, medical research, and modern industry.
Because control of the pH is essential in many industrial processes, some
years ago the Bureau took the lead in establishing a standard pH scale
which would meet the practical needs of industry and possess, as well, the
fundamental meaning demanded by science. Although standards for the
adjustment of pH-measuring equipment have been issued by the Bureau for
more than 15 years, fundamental difficulties in the calculation of a standard
pH have made it necessary to limit the accuracy in the assignment of standard
pH values to ±0.01 unit. However, during the past year, a mutually satis-
factory convention was developed in cooperation with the pH committee of
the British Standards Institution, and the third decimal place is now being
assigned to pH standard values.

A Standard for Blood pH. To discover the relationships that exist
among physiological function, pathological condition, and pH, medical and
biological laboratories have long studied the acid-base relationships in blood
and other physiological fluids. Because blood is a well-buffered fluid, the
changes in pH are very small and must be detected with precise pH-measur-
ing equipment. To increase the accuracy with which these measurements
can be made, the Bureau established a pH standard for determining the pH
of blood and other physiological media with a pH of 7.382 at 37 °C
(98.6 °F) . The new standard, a mixture of phosphate salts, can be prepared
from pH standard materials already issued by the Bureau.

Standard Hydrocarbon Blends, Eight standard hydrocarbon blends
are now available from the Bureau for calibrating instruments used in
analyzing gasoline and blending stocks. These standard samples — primarily
intended for mass spectrometer calibration — are mixtures containing seven
or eight pure hydrocarbons representing C7 and C8 paraffins and cyclo-
paraffins in typical virgin and catalytically cracked naphthas. The standards
may also be applicable for infrared and gas chromatographic techniques.
The development of this new group of standard materials is part of an exten-
sive and continual Bureau program to provide standard substances for
chemical and physical uses.

Preparative Scale Chromatography. During the past decade, vapor-
liquid chromatography has developed into an effective and widely used
method of separating mixtures. Although it was utilized chiefly for anal-
ysis, its use in preparing small amounts of pure materials gradually
expanded. As part of a program to extend the applicability of this method
to routine purification, a process for automatically injecting samples and
"cutting out peaks" to reject undesirable substances was devised. That is,
to purify a specimen, any component which has a peak different from the
characteristic peak of the specimen is automatically directed to a trap instead
of the main ampoule. With these innovations, the chromatographic
apparatus will operate automatically for long periods.

Additional improvements are being designed f or 'preparative scale chro-
matography. Because purification of small amounts of samples is more
effective in columns of relatively small capacity than that of large samples
in large-diameter columns, the automatic cyclic operation of small to inter-
mediate-size columns was chosen for further development.

Round-Robin Purity Determinations. Although any program di-
rected toward the preparation of pure materials is completely dependent
upon procedures for determining purity, the methods of gaging extent of
contamination unfortunately do not have the necessary reliability. To ob-
tain the best techniques for such a determination, a committee from the
Bureau organized an international cooperative study several years ago of
those techniques for determining purity which depend upon freezing-point de-
pression by impurities. Four groups of samples were prepared under con-
ditions designed to assure uniformity and verifiable purity. These speci-

mens were issued to 20 leading laboratories in six countries, including the
Bureau.

During the past year, the round-robin results that became available
demonstrated that accurate results can be achieved by this method. How-
ever, they also show that the sources of error are not always understood.
From the results, the most effective processes for determining purity were
found to be those in which changes in volume, heat content, or control of

Eight new standard hydrocarbon blends were issued for calibrating instru-
ments used to analyze gasoline and blending stocks. Ampoules are filled in a
controlled atmosphere with sufficient blend for one calibration (page 75).

the rate of freezing or melting were employed to judge the proportion of a
sample which was in the liquid state at any temperature.

Crystal Chemistry. Research on crystal chemistry was expanded to
obtain fundamental data on the formation, transformation, and purification
of crystalline chemicals in terms of molecular structure. As all physical
and chemical properties of solids are ultimately dependent upon structure,
it is necessary to understand the relationship between structure and behavior
of materials.

During the past year methods were evaluated for automatically recording
precise single crystal X-ray diffraction intensities, for deriving the approxi-
mate atomic structure of crystals from X-ray diffraction data, for obtaining
"flash" X-ray data from transient phenomena and for recording defects in
high-purity crystals.

Three types of investigations were continued on purification by single-
crystal growth: formation of pure single crystals, retention of impurities,
and effect of defect structure on the properties of crystals.

Coordination Chemistry. Both theoretical and practical interest in
the field of coordination compounds has increased in recent years because of
the unusual properties that these compounds exhibit. Through coordina-
tion with suitable complexing agents many metal ions can be either acti-
vated or deactivated. In addition, many of the coordination compounds were
shown to be useful catalysts whereas others were found to exist as inter-
mediates in reactions. To study the preparation, stability, and mechanism
and kinetics of formation of such compounds, the Bureau began an investi-
gation of coordination compounds of the first transition metal series. The
structure of these compounds is being studied with resonance spectroscopy
and X-ray diffraction techniques.

Radiochemistry. Considerable effort was devoted to designing a new
radiochemical facility for conducting fundamental investigations in radio-
chemical methods and for applying modern radiochemical techniques to
existing research problems. By detecting tracer atoms and measuring the
energy released from artificially radioactive species, the Bureau will study
mechanisms of chemical processes and develop sensitive analytical methods.
As part of this program, the analysis of trace constituents by neutron activa-
tion analysis will be stressed.

2.2.2. PHYSICAL CHEMISTRY

In response to the demand for more detailed information on the structure
of molecules and elementary molecular processes, the Bureau initiated a
program to consolidate and strengthen fundamental research on bulk proper-
ties of materials and macroscopic physicochemical processes. In the basic
experimental phase of this program, special instrumentation was developed
and precise data obtained on a wide variety of stable and short-lived molecular
species and systems. An associated phase of theoretical research was be-
gun to develop a coherent theory of molecular structure in relation to specific
molecular reactivity.

Research activities during the year include the elementary chemistry in-
volved in the synthesis of specially labeled compounds, in the processes
induced by radiation and particle-impact, and in the reactions at surfaces.
In addition, the structural and electronic parameters of relatively simple
stable and transient molecules were determined and special apparatus was
designed to measure relative isotope abundances for heavy elements, field
emission and ionization at surfaces, reactions at very low temperatures,
and fast reactions in transient complex systems.

Reactions of Atoms at Low Temperature. Chemical reactions be-
tween very reactive materials normally proceed extremely rapidly. By lower-
ing the temperature at which these processes occur, it is possible to slow
down the rate of reaction and thus make observations — for example, energies
of activitations — which are difficult to make at higher temperature. Through
recently developed techniques used in low-temperature research, chemical
reactions with low activitation energies can now be studied. The virtual
elimination of many secondary reactions at temperatures below 100 °K sim-
plifies the interpretation of kinetic data and permits an accurate determina-
tion of kinetic parameters.

In NBS studies, hydrogen atoms were found to react with oxygen at 20 °K,
with olefins at 77 °K, and with halogens at 90 °K. The primary reaction
products are free radicals which have transient existence and subsequently
dimerize and disproportionate to form stable compounds. The primary
addition-reaction of hydrogen atoms to propylene was studied in detail and
the activitation energy for this process was determined. At present, the effect
of substituents on the addition of hydrogen to substituted olefins is being
investigated.

Gas-solid Reactions at High Temperature. The failure of metals
at high temperatures caused by corrosive attack of hot gases is often a limit-
ing factor in the advancement of high-temperature technology. Because
physical and chemical data relating to these phenomena are often lacking,
the Bureau is conducting research on various aspects of high-temperature
gas-solid interactions at the request of the Atomic Energy Commission.
To facilitate this research, special equipment for molecular-beam studies
was developed. By using the molecular beam, the reaction between chlorine
atoms and a polycrystalline surface of nickel heated to temperatures between
1,100 and 1,600 °K was extensively investigated. Based on this study,
the relative reactivities of different crystal planes of copper and nickel to
halogens are being determined.

Light Elements. Data on the thermodynamic properties of light ele-
ments are essential for evaluating compounds composed of these elements
as potential high-energy fuels. To obtain such data, the Bureau is conduct-
ing a comprehensive interdisciplinary program of experimental and theoret-
ical work on light elements. For this research, which is under the joint
sponsorship of the Atomic Energy Commission and the Department of De-
fense, "best" values were selected for the heats of formations of a variety of

Apparatus for obtaining nuclear magnetic spectra, which reveal important in-
formation on the local electronic environment of nuclei in complex molecules,
on the sites of specific chemical reactivity, and on the pathways for communi-
cating electronic effects within these molecules (page 82).

boron compounds containing hydrogen, oxygen, fluorine, chlorine, and
bromine, and tables of thermodynamic functions for selected compounds were
compiled. Codes, which were prepared for high-speed digital computer cal-
culation of thermodynamic functions, were used to extend these functions to
6,000 °K for over forty compounds in the boron-oxygen-hydrogen-halogen-
nitrogen system. (See 2.1.5, p. 53, 2.2.3, p. 86.)

Measuring Isotope Effects, By substituting radioactive isotopes for
an atom in a molecule, the course of a substance can be traced through an
entire series of complex chemical processes. However, sometimes a bond
joining the isotope is altered in a rate-limiting step, causing a difference
between reaction rates for the isotopic and non-isotopic modifications of a
substance. The ratio of these rates is called the isotope effect. When the
isotopic atom is involved directly, large isotope effects, designated primary,
are obtained; when the isotopic atom is involved to a lesser degree, smaller
effects, designated secondary, are obtained.

Recently the Bureau developed a simple method for measuring isotope
effects. Two modifications of the reactant are used: One is labeled with an
isotope at or near the reaction center, and the other is labeled with a second
isotope at a point remote from the reaction center, where it does not affect
the rate of reaction. If the first isotope alters the rate of reaction, the ratio
of the two isotopes in the residual reactant and in the product changes as the

reaction proceeds. The value of the isotope effect can be calculated from this
change.

The method has been applied to the study of a variety of chemical, physical,
and biological processes. Thus, a five-fold tritium isotope effect was found
in the oxidation of D-glucose-i-Z with iodine. The commonly accepted mech-
anism for the oxidation of D-glucose-i-£ with chlorous acid was disproved
by the large isotope effect. Secondary isotope effects found in the oxidation
of D-mannitol-3-£ were attributed to hyperconjugation of the tritium in the
activated enzyme-substrate complex. The method opens up a vast field for
the study of reaction mechanisms.

Enolic Acids. Enolic acids, just recently recognized and considered
as a large class of organic compounds, have not previously been investigated
in any detail. Because these acids enter into unusual reactions, and because
only isolated data have been recorded on any specific enolic acid, the Bureau
is attempting a systematic determination of the reactions and properties of this
new class. Enolic forms were found for beta diketones, hydroxyquinones,
ascorbic acids, and many substances commonly considered as having acti-
vated hydrogen atoms. It is known that these acids differ from carboxylic
acids in that they contain a characteristic C-C = C-OH group in lieu of the

II
0

well-known carboxyl group.

A series of enolic acids can be prepared by chemical treatment of hexa-
hydroxycyclohexane. Removing hydrogen and eliminating water from the
hexane produces hexahydroxybenzene, hydroxyquinones, rhodizonic acid
and ultimately, cyclohexanehexone. The intermediates of this series estab-
lish reversible oxidation-reduction systems and provide a wealth of material
for correlating molecular structure with chemical and physical properties.
Improved methods were developed for preparation of tetrahydroxyquinone,
rhodizonic acid, croconic acid, and other compounds needed for studying the
acids. Mechanisms for aromatization and oxidation of the intermediates in
the production of these compounds were formulated and are now being tested
by model experiments.

Molecular Spectroscopy. As part of a continuing program devoted to
solving fundamental problems in molecular structure, detailed investigations
of the structures of several important molecules were carried out by spectro-
scopic studies in the ultraviolet, visible, infrared, and microwave regions.
Through the use of microwave techniques, interatomic distances in a variety
of hydrocarbons and their simple derivatives were measured with very high
accuracy. Small variations detected in the carbon-carbon bond lengths in
these molecules shed some light on the nature of the chemical bonds which
are involved. The microwave studies also provided such scientific data as
electric dipole moments and quadrupole coupling constants, which can be
correlated with the geometric structure of the molecules.

Other spectroscopic studies involved free radicals and molecular frag-
ments containing fluorine. The short-lived CF2 molecule, which is an im-

portant intermediate in flames and electric discharges involving fluorine,
was examined by flash photolysis and matrix isolation techniques. In the
former method, the ultraviolet absorption spectrum was recorded during the
very small fraction of a second that the molecule exists ; in the latter, the CF2
molecules were stabilized by isolating them in an inert matrix at a very low
temperature. Related studies were carried out on the emission spectrum of
CF from flames and discharges. In addition, an intensive investigation of
the recently-discovered NF2 radical was initiated. By measurement and
analysis of the infrared spectrum of NF2, the structure and vibrational fre-
quencies of this free radical were established.

The nonresonant microwave absorption in compressed quadrupolar gases
provided the basis for estimating molecular quadrupole moments. This
type of absorption can be used as a sensitive probe for examining the nature
of molecular interactions and relaxation processes. Values for the quadru-
pole moments determined for nitrogen, ethylene, and carbon dioxide are in
good agreement with the estimates calculated by other methods.

The mechanism by which hydrogen atoms are removed from ethane during
vacuum ultraviolet photolysis was determined. Such investigations give insight
into the interactions of various materials with high-energy radiation
(page 82).

The techniques of high-resolution nuclear magnetic resonance were applied
to the structural classification of isomeric conformers of derivatives of cyclo-
hexane. In general, the methods of analysis developed for the methyl disub-
stituted cyclohexane-l,3-diols appear to be applicable to the analysis of a wide
variety of saturated cycloparaffins.

Uranium Standards. Because the value of a uranium reaction fuel
depends on the abundance of the U235 isotope, accurate standards are re-
quired to make precise mass spectrometric determinations of this abundance.
In cooperation with the Atomic Energy Commission, a surface-ionization
mass spectrometer, which measures the isotope abundance in uranium oxide,
was developed and used to check a series of standard samples. Relating
to this work is the development of a method for determining the abundance
of U234.

A special mass spectrometer was developed for analyzing uranium hexa-
fluoride and is being used to evaluate standards having low concentrations
of U235. This instrument has been used to compare the natural abundances
of uranium in samples from different geographical areas. Differences as
large as 0.1 percent were detected.

Isotopic Abundance in Silver Checked. In the recent determination
of the absolute isotopic abundance ratio of silver, one of the natural silver
samples from Cobalt, Ontario, appeared to have a ratio significantly dif-
ferent from all the other samples. This difference suggested a naturally oc-
curring variation in isotope abundance for silver. Consequently, mass spec-
trometric study, partly sponsored by the Atomic Energy Commission, was
made on 13 samples of native silver from widely distributed deposits, in-
cluding samples from Cobalt. No significant variation from normal abun-
dance was noted for any of the samples. It is possible that the original
Cobalt specimen was a portion of an extraterrestrial sample.

Photolysis of Simple Molecules. To gain insight into the detailed
processes induced by different types of high-energy radiation, the Bureau is
continuing work on the photolysis of simple molecules. The mechanism by
which hydrogen atoms are removed from ethane during vacuum ultraviolet
photolysis was determined. When subjected to far ultraviolet light, ethane
molecules lose molecular hydrogen. Investigations on ethylene showed that
molecular detachment of hydrogen occurs under the action of gamma rays,
as well as under far ultraviolet light. The formation of molecular hydrogen
by the action of far ultraviolet radiation on water vapor was also observed.
This formation may account for the presence of hydrogen molecules in the
upper atmosphere.

In another investigation, excited hydrogen atoms, which are present in
the upper atmosphere, were produced in the laboratory in sufficient concen-
trations to study their reactions. Extremely active chemically, the hydrogen
reacts rapidly with nitrogen molecules to form ammonia, and may produce
small amounts of this gas at very high altitudes.

Radiolysis of Simple Hydrocarbons. Knowledge of the effects of
ionizing radiation on organic compounds is of great importance because of

Knowledge of the effects of ionizing radiation on organic compounds is im-
portant because of the rapid development and extensive use of nuclear reactors,
and because of the potential uses of high energy particles in synthesis. The
mass spectrometer (background) and gas chromatograph (foreground) are
used in the determination of primary processes in irradiated systems
(page 82).

the rapid development and extensive use of nuclear reactors, and because of
the potential uses of high-energy particles in synthesis. In order to provide
fundamental data on the behavior of irradiated compounds, the Bureau is
cooperating with the Atomic Energy Commission in research on the radi-
olysis of simple hydrocarbons. Molecular elimination processes which oc-
cur in the gas-, liquid-, and solid-phase radiolysis of ethylene, ethane, propy-
lene, propane, and isobutane were investigated. In general, by utilizing
partially and fully deuterated compounds, the several ways in which these
molecules may decompose can be unambiguously determined. For in-
stance, in all the hydrocarbons studied, hydrogen molecules were found to
split off from a single carbon atom as well as from adjacent carbon atoms.
In addition, by using radical scavengers to eliminate radicals, methane was
observed to be produced by molecular elimination from ethane, propane,
and isobutane. Studies of the effects of temperature, pressure, and inert
gases on the different processes aided in determining the relative importance
of excited-molecule decompositions in radiolysis.

Radical Reactions Formed by Irradiation, Detailed information on
elementary reactions is required to understand such complex phenomena as
oxidations and thermal decompositions. To obtain these data vapor-phase

radiolysis of selected organic compounds, such as azomethane and acetone,
was intensively investigated for the Atomic Energy Commission. The re-
sults can be explained on the basis of free radical reactions similar to those
occurring in the photochemical decomposition of these compounds. The
excellent agreement between the rate constants for the reactions which the
methyl radicals undergo in the radiolysis, as compared to the rate constants
obtained in earlier photolysis studies, indicates that only thermalized methyl
radicals take part in the reactions.

Electron Emission from Surfaces, As part of a program to charac-
terize the surfaces of materials, the field distribution of electron emission
near the surface is being determined. For this research, the temperature
variation of electron emission in the field-emission region was studied.
Results confirmed the theoretical relation that the fractional increment in
emission current varies as the square of the temperature. For an emitter
of known work function, the slope of the curve, depicting current increment
versus the square of the temperature, yields a precise value of the average field
at the surface of the emitter. This graphic method gives values which are
more accurate than those obtained by the conventional method which depends
on the measurement of the radius of the emitter with an electron microscope.
Field emission from niobium, both above and below its superconducting
transition temperature, failed to reveal a current increment attributable
to an energy gap associated with this transition.

2.2.3. MINERAL PRODUCTS

To provide basic information on a wide variety of inorganic, nonmetallic
substances, the Bureau conducts a two-fold program. One aim of this pro-
gram is to obtain precise values of specific constants and fundamental data
that are important to the scientific community. Related standard samples
and information on engineering research are developed as required. A
second aim is to devise techniques for preparing materials and measuring
their properties under carefully controlled conditions. This work includes
the extension of physical property measurements to the extremes of high and
low temperature, to high pressures, and into the realm of very pure substances.

During the year significant advances were made in developing techniques
for growing single-crystals of inorganic nonmetallic materials from the melt.
This research is being expanded to the study of fundamental mechanisms
of crystal growth processes.

Crystal Growth. Single crystals of high purity and perfection are ex-
tremely important for many fundamental studies of the solid state and for
developments in electronics technology. Some of the techniques now
used in basic and applied research are so sensitive that they are affected by
the residual impurities or imperfections present in refractory oxide crystals
of the highest quality now available. Thus, methods are needed for growing
such refractory crystals as sapphire (A1203) and rutile (Ti02) with much
greater control over purity and perfection.

As part of a program for the Atomic Energy Commission, the well-known
Verneuil process, which uses an oxyhydrogen flame, was used to produce
single-crystal rods of rutile with the conventional orientation of crystallo-
graphic axes as well as various uncommon orientations. The Verneuil
apparatus was modified to incorporate a radiofrequency plasma torch capable
of considerably higher temperatures than the oxyhydrogen flame. Improve-
ment upon the Verneuil process is expected to give better control over growth
of many refractory crystals.

Model Defect Structure, The presence of an impurity atom in a
crystal causes a distortion or defect in the crystal structure at that point. As
various types of defects are possible, it is usually difficult to predict what
type of defect will result from the introduction of a given impurity into a
given crystal. Sometimes the type of defect can be determined by assuming
a model for the defect, calculating the contribution of the defect to various
physical properties, and comparing the results with measurements of these
properties. The Bureau developed a particular model and a method of
calculating the temperature and frequency dependence of the resulting energy
loss. Predictions determined from this work were compared with experi-
mental results of thorium oxide containing small amounts of calcium oxide.

It was assumed that calcium atoms would substitute for thorium atoms
in the thorium oxide structure and that one oxygen vacancy would be asso-

The well-known Verneuil apparatus for growing single crystals of mineral sub-
stances was modified by using a radiofrequency plasma torch instead of the
usual oxyhydrogen flame. Single crystals of high purity and perfection are
important in studies of the solid state and the fundamental properties of
materials (page 85).

ciated with each calcium atom if the temperature was not too high. In the
absence of stress or electric field, each oxygen vacancy under the influence
of thermal vibration will move around its associated calcium atom; that is,
the vacancy will "jump" randomly from one to another of the eight oxygen
sites neighboring the atom. If an alternating electric field is applied, the
motion will no longer be completely random but will have a superimposed
regular motion driven by the field. Although this type of motion will also
occur if an alternating shear stress is applied, the details of the regular
motion depend on the type of drive (stress or electric field) and on the
orientation of the crystal with respect to the driving force.

The theory was worked out in detail and a peak was predicted in both
the mechanical loss (internal friction) and electrical loss (dissipation factor)
as a function of temperature. Experimental results, which fit this function
very well, suggest that the model correctly describes the behavior of oxygen
vacancies associated with calcium atoms for low concentrations of calcium.
Work is now underway on other defect models and other experimental
materials.

Vaporization Data. As part of a continuing program to furnish basic
data on some of the thermodynamic properties of light-element refractory
metals and oxides, investigations on the vapor pressures and rates of vaporiza-
tion of such substances were undertaken at the request of the Advanced
Research Projects Agency. Heats of vaporization of platinum, iridium,
rhodium, and palladium at 25 °C, as calculated from measurements of
the vapor pressures, are respectively 134.9, 159.9, 132.5 and 89.2 kcal/mole.
Preliminary data was obtained on the rates of vaporization of alumina in
a vacuum and in the presence of water vapor. (See also 2.1.5, p. 53.)

A major uncertainty in determining the thermodynamic data arises from
the measurement of temperature. Although the uncertainty for the palladium
data was considerably reduced with a technique in which a blackbody hole
was drilled in the sample, the uncertainty can generally be best reduced by
having more complete data on the emissivities of the samples. To facilitate
such measurements, apparatus was constructed to determine the angular
spectral emissivities of samples over a wide temperature range. This ap*
paratus is being used to measure the emissivities of many light elements and
compounds.

A second problem in interpreting vaporization data is associated with the
identification of the vaporizing species. For example, to obtain the vapor
pressures and heats of vaporization of the platinum metals, the gas species
were assumed to be monatomic, although diatomic molecules could also be
present. Only with the aid of a mass spectrometer can the species be deter-
mined with a high degree of assurance. Such a mass spectrometer was
specially designed for high-temperature vaporization studies in a program
sponsored by the National Aeronautics and Space Agency. The direction
focusing instrument used by the Bureau is of the Chupka-Inghram design
which pioneered the application of mass spectrometers in this type of research.

One of the basic problems in studying the behavior of materials at high tem-
peratures is identification of the vaporizing species. This special mass spec-
trometer was designed to identify the gas molecules which vaporize from solids
or liquids at temperatures up to 2,500 °C (page 86).

By using the apparatus, it is possible to identify the gas molecules which
vaporize from solids or liquids at temperatures up to 2,500 °C. In addition,
the relative abundance or partial pressures of the gas species may be deter-
mined. The instrument will be used to obtain basic data on the vaporization
of a wide range of high-temperature metals and compounds which are
important for rocketry, direct-energy conversion systems, and other
technological advances.

Mechanical Properties of Ceramic Bodies. The progress of high-
temperature technology is hampered by the inability of materials to with-
stand environmental design conditions and stresses. One of the foremost
obstacles blocking the improvement of existing materials and development
of better ones is the lack of fundamental knowledge on the structural and
thermal dependence of the mechanical properties of polycrystalline solids.

To bridge this gap, the Bureau is conducting a study on the influence of
microstructure on the mechanical properties of brittle, glass-free polycrystal-
line bodies. One phase of this program, sponsored by the Atomic Energy
Commission, involves theTstudy of strength, a structure-sensitive property of
a ceramic. Although strength is known to be very dependent on porosity and
grain size, only the general trend of this dependency is known. An empirical
general expression, which relates strength in terms of porosity and grain size,
was formulated. This equation has been applied to a number of ceramic
bodies such as alumina, thoria, urania, and chromium carbide.

The apparent temperature dependence of the two constants involved in the
equation indicates either that the form of the expression is incorrect even
though it is generally applicable, or that the apparent porosity and grain-size
effect is not produced solely by internal geometry changes, but also by some
other temperature-dependent factors acting in concert with the above changes.
The temperature dependence of the constants is currently being investigated
to determine the existence and nature of any associated factors.

The strength of a porous body is partially dependent on the extent of con-
tinuity within its weakest section. It has been proposed that the weakest
region within a brittle polycrystalline body is the area of contact or bonding
between grains. Accordingly, the strength of such a body would depend
on the relative size of the total projected area of contact or bonding traversed
by an irregular surface of minimal area passing intergranularly across the
load-bearing cross-section. Because porosity, as related to strength, is be-
lieved to be but an indirect, relative, inverse measure of the relative size of
such a projected area, an attempt is being made to determine the relative size
of this area, and to define the structure sensitivity of strength directly in terms
of this parameter instead of porosity.

Similar related studies are being conducted on the structural dependence
of the elastic properties of brittle polycrystalline bodies.

Resonance Techniques for Determining Elastic Moduli, Reso-
nant vibration techniques for measuring elastic moduli of glasses and ceramic
materials both at room temperature and elevated temperatures were de-
veloped during the past few years. As the techniques were improved, it was
found that the equations which were used for computing the moduli from
the resonance frequencies were not accurate. After systematic studies, the
technique for determining these frequencies was refined to the point where
the primary limitation on their use for computing the elastic moduli is the
accuracy of the corresponding theoretical equations themselves. Solution of
these equations depends on the geometry of the specimens, and generally can-
not be obtained in closed form. Empirical relations for specific geometries
were developed by accurately machining steel specimens of uniform elastic
moduli and experimentally determining their resonance frequencies. The
results are usually in the form of a table of correction factors of the theoreti-
cal solution for various geometries.

Similar empirical relations were also developed for other modes of vibra-
tion. For example, Young's modulus can be computed from the flexural

vibrations of cylindrical and rectangular bars, and shear modulus can be
accurately determined from torsional vibrations of square bars. At present,
equations are being developed for calculating Young's modulus from the
longitudinal vibrations of square and cylindrical bars.

Effects of Roughness on the Oxidation of Iron. Rough and smooth
metal surfaces have been observed to oxidize at different rates. For example,
roughened iron surfaces oxidize at a lower rate than smooth ones. This dif-
ference, thought to be related to variations observed in the bond strength
of alumina and zirconia coatings flame-sprayed on rough and smooth iron
surfaces, was systematically investigated to determine the oxidation rates of
both types of iron surfaces. This work is one phase of a research program
on particle-impact coatings requested by the Wright Air Development Center.

Experiments demonstrated that the over-all oxidation rate, and even the
rate per unit area, decreased for ingot iron roughened by grit blasting and
oxidized in air at 800 °C. This reduction in rate was found to be caused
by neither surface contamination, nor surface cold work, but by stress-
induced voids that form in the scale layer on roughened surfaces. By acting
as barriers to the outward diffusion of iron ions, the voids lower the rate at
which roughened specimens oxidize. This interpretation was confirmed by
microscopic examination of specimens roughened by simply machining small
grooves in the surface. The voids clearly formed over convex portions of
the iron surface with small radii of curvature.

This effect determines the complex course of the oxidation of impure iron
with an initially smooth surface. In the early stages of oxidation, the
rate followed a parabolic curve with the rate constant equal to the slope
of the curve. With continued oxidation, however, the surface became
roughened and the rate constant decreased. After a transition period, para-
bolic oxidation was re-established but with a lower rate constant. On the
other hand, specimens of high-purity iron (99.9903%) with smooth surfaces
not only remained smooth throughout a three-hour oxidation period but they
also oxidized parabolically with a single rate constant.

Standard X-Ray Diffraction Patterns, Standard X-ray diffraction
patterns in the form of card files are widely used in research and industry as
a rapid and accurate means of identifying crystalline materials. To aid in
producing new patterns, the Bureau developed a controlled humidity
chamber. This chamber provides the appropriate atmosphere in which any
hydrate may be maintained in equilibrium while X-ray patterns are being
made. By utilizing this technique, hydrates not previously available can
be effectively measured.

A camera was designed to measure the unit cell parameters of crystals to
an accuracy of one part in 100,000. A back reflection focusing type, the
camera has a glass photographic plate to minimize film shrinkage errors.
It employs a microfocus X-ray source and is placed in an insulated chamber
with a temperature control constant to 0.01 °C. Data obtained with this
instrument will be useful for studying the relation of cell size to variation

616114 0—161—7 89

of composition and to defect population as well as for determining the inter-
relationship of atomic constants such as Avogadro's constant, wavelength of
X-rays, and atomic weights.

Deuterium Isotope Effect in Glass Transformation. Explicit un-
derstanding of the glass transformation process, which results in formation of
the vitreous state, requires identification of modes of molecular motion.
Such motions, immobilized when a substance is cooled through the tem-
perature region of glass transformation, can be studied in glass-forming
aqueous solutions by measuring and interpreting deuterium isotope effects
on glass transformation temperatures. A glass transformation temperature
of a non-crystalline substance is an operationally specified temperature below
which the substance exists as a glass, and above which it exists as an
equilibrium super-cooled liquid.

Many aqueous solutions form glasses which have transformation tem-
peratures in the neighborhood of — 150 to — 125 °C, as determined by differ-
ential thermal analysis. The value for an individual solution does not vary
with solute concentration below approximately 10 mole percent. Complete
substitution of D20 for H20 as the solvent in sulfuric acid solution raises
the glass transformation temperature 2.6 °C, from —129.5 to —126.9 °C.
For partial D20 substitution the rise is linear with the extent of substitution.
For hydrochloric acid the rise for complete substitution is 3.7 °C, from
-145.0 to -141.3 °C.

An improved understanding of intermoleeular forces is the objective of this in-
vestigation of the effects of pressure on the refractive index of liquids. The
liquid under investigation is placed between the plates of a special interferom-
eter (in box, right) and the interference fringes are observed visually
(page 91).

These deuterium isotope effects are caused by the difference in atomic
masses of deuterium and hydrogen — deuterium is twice as heavy as normal
hydrogen. Because the two types of atoms are isotopes, they are approxi-
mately equivalent in most other aspects. Thus, with other variables remain-
ing nearly constant, the isolated effect of the mass change can be measured.
Final molecular interpretation of these results requires additional informa-
tion about the magnitude of the potential energy barriers separating successive
molecular configurations in the equilibrium super-cooled liquid. However,
these data are roughly consistent with the existence of successive molecular
configurations differing in the relative position of individual water molecules
with respect to their neighbors.

Ultra Low-Conductivity Water. Water, because of its abundance, its
importance to the physical sciences, and its role as a life-supporting liquid,
has been the subject of intense study for many years. Yet, despite all this
research, water apparently had not been produced with a small ionic content.

The Bureau, however, recently succeeded in preparing water of extremely
low ion content by applying an electrophoretic ion-exclusion technique. The
water obtained has an electrical conductivity of 0.039 X 10"6 ohm ~} at
18 °C, indicating a residual ion content which is equivalent to a sodium
chloride concentration of one part per billion. Containing less than one-
third of the ionic impurities of the water prepared by Kohlrausch and
Heydweiller in their historic purification experiments in 1894, this water
approaches ideal purity and its conductivity is closer to the theoretical value
than that of any water preparation of which has been previously reported
in the literature.

In designing the purification procedure, two principal considerations were
involved. First, instead of using multiple distillation as in the classic ex-
periments, an electrophoretic procedure was applied. In this way purest
water was obtained in 2 hours. Second, the purification apparatus was
designed to recirculate the purified water continuously through the electric
field, thus immediately removing any ions which might originate from the
walls of the apparatus and contaminate the already purified water.

Because this pure water has ultra low conductivity, it was used to study
the dissociation equilibria at different temperatures. The cross relations of
physical data which describe such important properties of water as the dis-
sociation constant, were verified from this study.

Index of Refraction of Liquids, To develop a better understanding
of intermolecular forces, the effect of pressure on various materials is
being studied. As part of this program, the effects of pressure upon the
refractive indices of benzene, carbon tetrachloride, methanol and water were
determined. An interferometric technique was developed to measure the
index of refraction to the fifth decimal at pressures as high as 1 kb and at
temperatures between 10 and 60 °C.

For the measurements, the desired liquid is enclosed in part of the inter-
ferometer (the etalon) which, in turn, is contained in a pressure vessel
having observation windows. A collimated beam of light enters the con-

tainer and produces an interference pattern which is observed outside the
vessel. As pressure is applied to the system, the effect of pressure on this
pattern is recorded. Distortions in the windows of the vessel produce no
significant errors, while distortions of the interferometer, which is subject
to hydrostatic pressure, can be evaluated satisfactorily.

In the absence of intermolecular interactions strong enough to alter the
electronic energy levels in the molecules significantly, the index of refraction
is expected to be a function only of the specific volume. However, inter -
ferometric data show that even at constant volume, the index of refraction
for a given liquid depends upon the temperature. This dependence can
arise from a change in either the resonant frequency or the intensity of spec-
tral absorption lines. To understand better the nature of the interactions
involved, the Bureau is extending the study of pressure and temperature
effects over the whole visible spectrum.

2.2.4 METALLURGY

Metallurgical research at the Bureau is directed toward a better under-
standing of the properties of metals in order that improved metals and
alloys may be developed to meet new requirements or to give better per-
formance. Fundamental information is needed, and much of the work is
designed to further our understanding of metals and alloys in terms of their
constituent atomic units. Particular emphasis is placed on problems related
to metals subjected to high temperatures, and to corrosion and fatigue, and
to the preparation of pure metals. Crystal growth, electronic properties,
atom mobility, and lattice imperfections of metals are studied as well as the
effect of treatment, fabrication, and conditions of service on their structure,
behavior, and properties.

Vapor-Phase Crystallization Studied, To obtain a better under-
standing of the process of crystallization of metals, quantitative measure-
ments of vapor-phase crystallization under precisely known conditions are
being made. This work includes kinetic studies of the growth of potassium
and mercury crystals as a function of vapor supersaturation, temperature,
and amount of impurities present. Recent results on high purity potassium
distilled in ultra-high vacuum showed that potassium crystals could grow
at very low vapor supersaturations ; that is, in the absence of surface nuclea-
tion. The experiments were performed in carefully baked-out and outgassed
tubes and contradict the results obtained in experiments with crystals of lower
purity or less well prepared growth tubes. Growth rates, measured across
two opposite faces on a potassium single crystal about 1 mm in diameter,
were as low as 1 A per second at the lower supersaturations. The mercury
crystals under study are in the form of "whiskers," about 100 A in diameter
and 5-25 microns in length. As these nearly perfect crystals grow in an
electron field emission tube, precise measurements of length, radius, and
other properties can be made as a function of time, temperature, and
supersaturation.

Oxidation Processes Studied, During the year a study was made
of the influence of a metal substrate on the properties of the oxides formed
on the metal surface. Experiments with aluminum single crystals disclosed
that the crystallographic orientation of the substrate upon which the oxide
grew decidedly influenced the shape and orientation of the markings appear-
ing in the oxide film. When the substrate was melted, the oxide film —
because of its higher melting point — remained intact. When the substrate
recrystallized, the film retained its original markings, with new markings,
characteristic of the new substrate orientation, being introduced. Each time
this process was repeated, new markings appeared.

Another study, concerned with the sites of passive film breakdown on iron,
revealed the influence of the crystallographic orientation of the metal sur-
face. This breakdown occurs at discrete sites whose number per unit area
depends upon the crystallographic orientation of the surface bearing the film.
This study also revealed that the formation of the passive film is a two-step
process. To gain a better understanding of this phenomenon, studies on the
formation of the first monolayers of oxide were initiated. The surfaces of
iron, nickel, titanium, and mercury whiskers were observed in a field emis-
sion microscope and studies of the oxidation process are under way.

Nuclear Magnetic Resonance, Nuclear magnetic resonance tech-
niques are being applied to the investigation of the electronic band structure
of hard metals ( intermetallic compounds) having the crystal structure of
sodium chloride. In metals, the position of the center of the nuclear reso-
nance line usually shows a relative displacement toward lower fields, com-
pared with salts of the same atom. This paramagnetic displacement (known
as the Knight shift) is thought to have its origin in the contact hyperfine inter-
action between the "s" conduction electron spin and the spin of the nucleus
under observation. Both the tantalum resonance in tantalum carbide and
the niobium resonance in niobium carbide were measured and found to have
diamagnetic Knight shifts. These results suggest the atomic s-levels are de-
pressed in the solid completely below the Fermi level and thus do not con-
tribute to the high electrical conductivity of these materials.

Superconductor Materials, A recent observation that the nio-
bium-tin (N'b3Sn) intermetallic compound retains its superconducting prop-
erties in magnetic fields of the order of 100 k Gauss stimulated interest in
the basic understanding of "hard" superconduction, and in the possibility
of fabricating superconducting magnets for the production of very high mag-
netic fields. The Bureau's cryogenic engineering laboratory at Boulder
(Colo.) plans to make a magnet from Nb3Sn specimens prepared in the
Washington, D.C., laboratories (see p. 143). The specimens are com-
posite wires 0.015 in. in diameter consisting of a core of Nb3Sn sheathed in
pure Nb. These wires remained superconducting in magnetic fields as high
as 185 k Gauss.

Little information is available on other types of alloys which may be
utilized as windings for high-energy cryogenic magnets. Hence, extensive
research and testing programs are being formulated to enhance our knowl-

edge of these alloys and broaden their applicability, particularly in the area
of controlled nuclear energy.

Soft X-ray Spectroscopy. Interest has recently been stimulated in
soft X-ray spectroscopy because it provides information on the density of
electronic states in the valence band of solids. To provide such data on
metals, the Bureau is constructing a soft X-ray spectrometer which employs
a curved glass grating. It is ruled with 30,000 lines to the inch, and has
photomultiplier detection. Initially the research effort will be directed
toward obtaining emission spectra from intermetallic compounds and their
constituents over a wide temperature range. The results will contribute
critical data for the eventual formation of a quantitative theory of bonding
in metals and alloys.

A measuring microscope is used to measure the distance between two faces on
a potassium crystal growing from the vapor phase inside a dewar vessel. In-
set shows potassium crystal about 0.9 mm in diameter. Studies of funda-
mental crystallization processes in metals provide a better understanding of
the physical properties of the materials (page 92).

Diffusion Studies Continued. Theoretical studies of the details of
atomic motions which cause diffusion in crystalline solids were continued.
If a metal containing dissolved impurities is held in a temperature gradient,
a current of impurities is induced until a steady state gradient is established.
The induced current, the steady state gradient, and the mean atom drift
velocity in a dilute alloy were calculated in terms of the kinetic parameters
describing the jumps of the atoms from one lattice site to another. General
equations were developed which can also be applied to diffusion in other
types of gradients, such as a chemical concentration gradient in a non-dilute
alloy or an electrical gradient.

Dislocations Observed in Metal Foils, A study was made of the re-
lation of surface chemical etch pits to dislocations in thin single-crystal cop-
per foils. The experimental technique involves direct observation of dis-
locations by transmission electron microscopy. The results indicate that
certain etching solutions are sensitive to the presence of dislocations and
other crystal defects, but that a precise one-to-one relation is not generally
obtained. The method should be applicable to many fundamental studies of
corrosion reactions on metal surfaces.

Phase Diagram of Quaternary System Completed. The increas-
ing use of multicomponent alloy systems to obtain desirable mechanical prop-
erties and corrosion resistance of metals at high temperatures has focused
attention on the solid-state reactions occurring when a complex alloy is heated
at different temperatures for prolonged periods. Alloys whose basic com-
positions include iron, chromium, nickel, and moylbdenum compose one of
the important alloy systems in this class. In determining the composition
limits of the reacting phases at various temperatures in this system it was
found necessary to redetermine portions of the equilibrium phase diagrams
in the Cr-Ni and Fe-Mo binary systems. Considerable new data also had
to be obtained on the Fe-Mo-Ni and the Ni-Cr-Mo ternary systems before the
Fe-Cr-Mo-Ni quaternary system could be completed.

Mechanical Properties of 17—7 PH. Stainless Steel Investigated.
The mechanical properties of 17-7 PH (17 percent chromium-7 percent
nickel) stainless steel foil were determined following various aging treat-
ments. An explanation for the brittle condition resulting from aging at
temperatures less than about 970 °F was evolved. It was found that the
improved strength properties and retention of significant ductility of material
aged above 970 °F results from the simultaneous precipitation of an extremely
fine compound within the martensite grains, and the reversion by transforma-
tion of some body-centered cubic alpha (martensite) to face-centered cubic
gamma (austenite) . The change in properties and structure was observed by
using X-ray diffraction, integrated intensity measuring techniques, and re-
cently developed bulge-test equipment.

Identification of the hardening compound formed during aging was accom-
plished using an electron microscope and selected area-diffraction techniques.
Examination of carbon extraction replicas of samples aged for 68 hours

Studies of physical and chemical processes on metal surfaces are made at mag-
nification of a million times by field emission microscopy. The image of the
metal surface shows up on the fluorescent surface of the bulb in the lower
right corner of the picture (page 93).

revealed crystallographic structure of the precipitate to be the cesium chloride
body-centered-cubic type with a lattice parameter of 2.909 A.

Properties of Iron Reviewed. A comprehensive review and com-
pilation of all of the known physical, mechanical, and thermodynamic prop-
erties of iron was completed and published. The data include all property

values so far established for the NBS high-purity irons, as well as values for
other irons of higher than commercial purity.

Quantitative Metallography Obtained with Digital Computer.

The Bureau's SEAC computer, SADIE picture scanner, and "STRIP-II"
library of computer sub-routines were used to work out methods for perform-
ing quantitative metallographic operations on micrographs, both of metal
powders and of normal polished sections. With this process, metallographs
are automatically scanned and translated into language suitable for computer
input. Particle-size and grain-size analyses are typical of the operations
performed. An additional sub-routine, producing 11 parameters descriptive
of metallographic grains, was composed and incorporated into the STRIP-
II series. Preliminary planning was completed for additional routines and
for the extension of the work to larger pictures when the Bureau's new Pilot
computer becomes fully operative.

Gases in Metals. The first standards for the hydrogen content of ti-
tanium and its alloys were certified and made available. These standards
consist of titanium sheet at three levels of hydrogen content, 32, 98, and 215
ppm. A study is now being conducted to establish standards for the oxygen
content of several of the titanium alloys. In the ferrous alloys, work is
progressing on two new standards representing vacuum-melted steel and
stainless steel.

Gage Blocks. The Bureau is continuing its long-range program to
develop gage blocks that will maintain a dimensional stability of 0.1 or 0.2
microinches per inch per year. Thus far, several groups of experimental
blocks have met this stability requirement. Nitrided 410 stainless-steel
blocks with annealed cores demonstrated especially good stability over a
period of three years. In addition, these blocks have other desirable char-
acteristics, such as high hardness, ability to take a high degree of surface
finish and parallelism, resistance to corrosion, and a favorable coefficient of
linear expansion. Other promising series include blocks of 52100 steels, and
experimental steels were designed and processed that are expected to exceed
the performance of the 410 composition. Studies are being conducted to
establish the inter-relations of chemical composition, heat treatment, structure,
residual stresses, surface films, case depths, and dimensional stability of
gage blocks.

Creep Studies Continued. To provide basic information on the creep
of metals, studies are continuing to be carried out on the creep characteristics
of the nickel-copper system under carefully controlled conditions. In a
recent investigation, the effects of cold-drawing on the creep resistance of
high-purity nickel, and two nickel-copper alloys (70 percent Cu-30 percent
Ni; 30 percent Ni-70 percent Cu) were evaluated, and the results were
correlated with those previously obtained on cold-drawn copper and annealed
metals and alloys. It was found that, in general, the resistance to creep at
temperatures below recrystallization was increased by cold-drawing and
(at all temperatures investigated) by mutually alloying the nickel and copper.
At creep temperatures above recrystallization, the effects of cold-working

were practically eliminated and the creep behavior of the initially cold-worked
metal was similar to the corresponding metal as annealed.

Organic Films Increase Fatigue Strength. Fatigue, or the failure
of metals under repeated loads is profoundly affected by the environment
at the surface of the metal. With many metals, the surface reactions oc-
curring in a normal indoor atmosphere are sufficient to reduce fatigue
strength below that observed in vacuum or in an inert atmosphere. Recent
work, under the sponsorship of the National Aeronautics and Space Ad-
ministration, showed that the deleterious atmospheric effect was virtually
eliminated when the surface was coated with certain organic liquids that
form adherent films on metal surfaces. In extensive tests the beneficial effect
of the films was operative during both the crack initiation and crack propa-
gation stages of fatigue failure.

Metal Polarization Indicates Corrosion Rate. During the past sev-
eral years the polarization characteristics of metals were studied while the
metals were corroding in aqueous solutions. The studies definitely show that
the effects of factors such as precipitation, temperature, inorganic coatings,
and metal composition upon the rate of corrosion can be determined directly
from polarization curves, and that the performance of metals can be rea-
sonably well predicted under many corrosive conditions.

Stress Corrosion. In stress-corrosion research it was found that some
plastic deformation must take place in a magnesium alloy before stress-cor-
rosion cracks can develop. Cracking probably does not occur in those crys-
tals which are favorably oriented for slip to occur, but it does take place
in those crystals which are resistant to easy plastic deformation. This work
was partially supported by the Corrosion Research Council and the Atomic
Energy Commission.

Heat Effects of Electrochemical Processes. The various heat effects
that are associated with electrochemical processes are being investigated
calorimetrically at the request of the Atomic Energy Commission. This
work is concerned with the measurement of the enthalpy change (Ai7) of
electrochemical reactions, and with electrode polarization and complex
equilibria in solution. Another study of the entropy change (AS) of half-
cell processes, dealt with the entropy of ions in water solution and with
transport processes in electrolytic cells. The heat effect caused by the pas-
sage of an electric current across the interface between two electrolytes is
also being investigated.

Research with Molten Salts. In an earlier program to provide basic
data on the electrochemistry of molten salt systems, a new type of reference
electrode employing a sodium ion conductive porcelain, was developed. In
further work this year, a similar porcelain was found suitable for the elec-
trodes in a cell used for measuring the transference numbers of molten
sodium nitrate. It was also found that similar porcelains can be made that
are conductive to other monovalent ions, when in contact with a correspond-
ing melt. Another fused salt project in progress consists of a study of
complex equilibria by means of high-temperature calorimetry.

Rotating beam fatigue-testing equipment used to study the effect of various
components of the atmosphere on the fatigue properties of metals. Studies
in controlled atmospheres show that fatigue is profoundly affected by the en-
vironment at the surface of the metal (page 98).

Mechanism of Metal Deposition Studied, The mechanism of elec-
trodeposition is the subject of two experimental investigations, one on the
mode of growth of copper crystals, and the other on the phenomena oc-
curring when a metal is deposited by microsecond pulses of current. The
growth of crystals is being studied by electrodepositing copper on isolated
faces of single crystals and examining the topography and structure of the
deposits by metallographic methods and X-ray diffraction.

In this work valuable information is being developed on the relationship
between the conditions of electrodeposition, the crystal face on which the

deposition occurs, and the mode of growth of the deposit. Under some con-
ditions the deposit has a single crystal structure and appears as a continua-
tion of the seed crystal. Under other conditions the deposit may start as a
single crystal and gradually become polycrystalline with time, or — as a
consequence of topographic features — it may form as a single crystal with
boundaries parallel to the direction of growth.

Preliminary experiments with extremely short pulses of current show that
copper deposits from a sulfate bath at high current efficiency with current
pulses of one microsecond, but that efficiency decreases with shorter pulses.
During a single pulse of about one microsecond duration, at a high current
density, a deposit of copper in the form of a dendrite was formed. An ex-
tended study of the characteristics of deposition of metal with short pulses
of current is expected to contribute information on the mechanism of
electrode reactions and deposit formation.

Electrode position from Organic Solutions. Aqueous solutions are
not suitable for electroplating on chemically reactive metals such as uranium
if the coating is to be strongly adherent to the substrate. A study, par-
tially supported by the Atomic Energy Commission, was therefore under-
taken to investigate the electrodeposition of metals from organic solutions.
Although the problem of coating adhesion was not completely solved, sound
coherent coatings of zinc and of copper were obtained from solutions of their
respective salts in formamide. Under suitable conditions, coatings could be
easily built up to several hundred microns in thickness. It was also found
that tin could be readily electrodeposited from dimethylformamide solutions
of stannous chloride. None of these deposits, however, formed as smooth
coatings. Instead, they grew in the form of large ductile crystals which were
shown to be single crystals by X-ray diffraction.

2.2.5 ORGANIC AND FIBROUS MATERIALS

Research on the properties of organic and fibrous materials covers both
natural and synthetic polymeric structures. To gain a better understanding
of the relationships between the composition and the properties of polymers,
studies are being conducted on rubbers, textiles, papers, leathers, plastics,
dental resins, and related materials. The properties of polymers depend
upon the size, shape, distribution, and flexibility of their molecules, and
on the interactions of the molecules with each other. A more basic knowl-
edge of their fundamental properties and improved measurement techniques
are necessary for the development and efficient utilization of these materials.

During the past year fundamental studies were made of the kinetics of
crystallization, the melting temperatures of crystallites, the nature of free
radicals formed in gamma-irradiated polymers, the thermal stability of
polymers exposed to a temperature of 1,200 °C, and the polymerization
induced by ionizing radiation of monomers confined under high pressure.
The propagation of strain waves in fibers subjected to high-velocity tensile-
impact loading was investigated as well as the energy-erosion relationships

100

involved in collision of meteorites with potential spacecraft structural mate-
rials. Chemical studies included vulcanization-type reactions, chrome-vege-
table tannages, and crosslinking mechanisms and effects on properties of
synthetic fibers. Analytical methods were developed for alum-coagulated
styrene-butadiene rubber and for 5,6-dichlorobenzoxazolinone to be used as
a mildew-preventive in leather. Hydrogen bonding in calcified tissues, the
dimensional stability of resin dentures, and particle size and shape effects
on strength of amalgam alloys were investigated.

New Method for Analyzing Synthetic Rubber, The extraction pro-
cedure generally used for the analysis of alum-coagulated styrene-butadiene
rubber gives low results for organic acid, probably because of interference
from aluminum ions which tie up some of the organic acid. A procedure
was therefore devised for preventing this interference by preferentially re-
acting the aluminum ions with 8-hydroxyquinoline, and thus freeing the total
organic acid for titration. The technique employs meta-cresol purple as
an indicator to distinguish the organic acid from the mineral acid formed
in the reaction. Both the reaction and titration are carried out in an organic
solvent suitable for dissolving the rubber. With the use of only a single
weighed sample, the procedure may be adapted to the determination of other
gross constituents of alum-coagulated SBR.

Nylon fiber (above) develops helical coils (below) after chemical treatment.
Such artificially induced structural changes may lead to fibers which will resist
extreme environmental conditions (page 102).

101

Model Compounds Used in Vulcanization Studies, Natural rub-
ber reacts with sulfur and organic accelerators in the normal vulcanization
process, but details of the reaction are obscure. Apparently double bonds
are necessary, since the reaction does not occur with hydrogenated rubber.
Studies of the reaction of sulfur, hydrogen sulfide, and accelerators with two
simple model compounds, one a propylene containing one double bond, and
the other, a butadiene containing two double bonds, showed the formation
of sulfides, disulfides, and carbon-to-carbon bonds. Butadiene with its
conjugated double bonds served as a model compound for the conjugated
system formed in the vulcanization of rubber. A dithiocarbamate accelera-
tor was found to facilitate the formation of hydrogen sulfide and then to
promote the reaction of hydrogen sulfide with propylene or butadiene. Some
reactions included the formation of compounds from free radicals originally
present. Appreciable portions of the products were nonvolatile.

Crosslinks Determined in Anisotropic Fibers. The Flory-Rehner
theory of isotropic swelling of rubber crosslinked in the dry state was extended
to an anisotropic system crosslinked (short crosslinks) in the dry, oriented
state. The new parameters introduced into the equation were readily deter-
mined from dimensional changes of the fiber in a suitable solvent using a
photomicrographic technique. With this technique swelling equilibrium can
be attained within 30 minutes. In the study, surprisingly good agreement
was found between the equivalents of crosslinks calculated from swelling
measurements and from chemical analyses.

Impact Loading of Fibers. In many civilian and military applica-
tions the performance of textile materials subjected to high rates of strain
by impact loading is not well understood. An investigation was therefore
made of the behavior of representative textile yarns subjected to impact
loading at velocities of 150 ft/sec in which Von Karman's concept of critical
velocity (that velocity at which a filament breaks immediately upon impact
in tension) was extended and applied. In the study, critical velocity estimates
were arrived at, ranging from 400 ft/sec for glass fibers to 950 ft/sec for
nylon and some high strength rayons.

Mechanism of Retannage Studied. A combined chrome-vegetable
tannage not only converts hides more rapidly into leather than a single tannage
but the combination improves abrasive wear and tannage stability. Recent
work showed that a reaction, probably of the chelate type, occurs between
chrome and the vegetable tannage, and that the affinity of the substrate for
tannin is at a peak when 2.5-3.5 percent of a chromium complex (percentage
calculated as chromic oxide) is present. Experiments indicated that a copper
compound gave results similar to those obtained with chromium. It there-
fore appears that other metallic salts may be developed for future uses in
combination tannages.

Synthetic Fibers Structurally Modified. To provide basic informa-
tion for the development of structurally modified fibers that will resist extreme
environmental conditions, the Bureau conducts fundamental research on the
properties of synthetic fibers. In this program, efforts are made to correlate
the chemical properties, heat and radiation resistance, and polyelectrolytic

102

Polymers have been produced from materials, such as carbon disulfide and
nitrogen, which do not form polymers under ordinary conditions. A combi-
nation of high pressure and subsequent exposure to intense gamma radiation
was used to induce polymerization (page 104).

behavior of structurally modified fibers with size, number, and kind of cross-
links and grafts in the polymer fibers.

In preliminary investigations, unexpected crimping and helical coiling
occurred when solid nylon-6 homofibers (homogeneous one-component fibers
with round cross sections) are treated with a swelling agent and disulfide and
poly (methylene sulfide) crosslinks inserted while the fibers are in the swollen
state. Subsequent crimping in the dry state is attributed to heterogeneous
crosslinking. Helical coiling occurs when the crimped fibers are treated with
a strong swelling agent which completely destroys the remaining crystallites.

Polymer Crystallization Studied. Although thermodynamic equi-
libria can be applied to the crystallization and melting of polymeric materials,
these large molecules behave somewhat differently -from small ones, partly
because they never become completely crystallized. If crystallization of

103

high molecular weight polymers takes place at temperatures below the
equilibrium melting temperature, the resulting crystals will melt at a lower
temperature than if they had formed nearer to the equilibrium temperature.

In a recent study, an equation was developed that gives a mathematical rela-
tionship between the melting temperature of a crystallite formed at non-
equilibrium temperatures, the equilibrium melting temperature, and the tem-
perature of crystallization. This relationship was found to agree very well
with experimental values obtained from studies of the crystallization and
subsequent melting of rubber under nonideal conditions.

A theoretical study of polymer crystallization mechanisms revealed that
crystallization rates and isotherm shapes are sensitive to small amounts of
structural irregularities in a polymer chain. This behavior results from a
compositional change in the melt, which causes a marked decrease in the
nucleation rate during crystallization. The theoretical conclusions, which
were confirmed by experimental observations, indicate that chain irregular-
ities as little as one mole percent should be detectable.

High Pressure Polymerization. Many molecules that have double
or triple bonds in their chemical formulas — for example, carbon disulfide and
nitrogen — do not form polymers under usual conditions. In general, when
attempts are made to polymerize such molecules, the chemical equilibrium
favors monomer instead of polymer production. However, if very high
pressures are applied, the equilibrium will be displaced to favor polymeriza-
tion. Reaction can be initiated by heat, catalysts, or ionizing radiation. In
work for the Office of Ordnance Research, materials were placed under
pressure in a bomb and exposed to gamma radiation. When irradiated, per-
fluoroheptene polymerized to a moderate degree, whereas when unirradiated,
no polymer formed. At 10,000 atm, 50 °C, and under irradiation, carbon
disulfide formed a polymer which was previously obtained only at 50,000
atm and high temperature.

Thermal Stability of Polymers. The relationship between thermal
stability and molecular structure of polymers was investigated at pyrolysis
temperatures up to 1200 °C. In this program, sponsored by the Air Force,
polymers which are originally highly crosslinked — such as polytrivinyl-
benzene and phenolic and epoxy resins — and polymers which develop cross-
links at the pyrolysis temperatures — such as polyvinylidene fluoride and
polyacrylonitrile — were observed to yield carbonaceous residues and low
molecular weight volatile fragments. When polymers which do not become
crosslinked — such as polystyrene, polymethylene, and polytetrafluoro-
ethylene — were heated to pyrolysis temperatures, only volatile products of
low molecular weight were noted. In either case, the higher the tempera-
ture, the greater is the fragmentation of the degradation products. This re-
search has yielded additional proof that the energy-absorption capacity of a
polymer during thermal degradation is inversely proportional to the
molecular size of the volatile fragments. Furthermore, it has demonstrated
that polymers which leave a carbonaceous residue and liberate gases at the
elevated temperatures generally give superior ablation resistance in missile
nose cones.

104

Free Radicals in Polymers. Free radicals can be observed, estimated
quantitatively, and sometimes identified in very small amounts by electron
spin resonance spectroscopy. As part of a program sponsored by the Air
Force to investigate the reactions of free radicals in polymeric systems,
a number of polymers, including polystyrene, cellulose, and fluorocarbon
polymers, were irradiated and examined. Considerable new information
was obtained on the mechanism of polymerization and on the chemical
changes induced in these polymers by ionizing radiation. In addition,
fluorocarbon monomers were observed to yield appreciable amounts of free
radicals when irradiated at liquid-nitrogen temperatures.

Fungicidal Analysis. A study was undertaken to find a means for
determining the quantity of 5,6-dichlorobenzoxazolinone in leathers. This
compound is used as a fungicide to prevent mildew in leather, and an analyti-
cal technique was required by the Office of the Quartermaster General for
treatment control. A colorimetric method was devised which consists of
the conversion of 5,6-dichlorobenzoxazolinone to 2-amino-4,5-dichlorophenol
by alkaline hydrolysis, diazotization of the aminophenol, coupling with resor-
cinol to give a colored azo compound, and photometric measurement of the
color. A chloroform-water mixture is used to extract the fungicide. Vege-
table tannins which would interfere with color measurements are precipitated
with lead acetate and removed in the aqueous phase of the extract which is
discarded. The interfering effect of chromium is also overcome, either be-
cause the water in the mixture prevents formation of a chrome-fungicide
complex, or because the chrome itself is removed in the aqueous phase.

Meteorite Erosion of Materials. The possible hazard of meteors to
the space-craft of the future has recently been made more significant by the
discovery of a charged zone around the earth which attracts meteoric par-
ticles. When small masses, traveling at the velocities at which meteors travel,
collide with solids, the transformed energy is so large that both the projectile
and the target in the immediate vicinity liquefy after collision. The extent
of this meteorite-erosion hazard is being investigated, in research sponsored
by the Air Force, by examining the craters produced in collisions of liquid
drops with liquids, and in collisions of metal spheres with metal plates, at
velocities up to 20,000 ft/sec. An equation was derived relating the maxi-
mum depth of the cavity produced in a target liquid as a result of collision
with a liquid drop, to the kinetic energy of the impinging drops.

Calcified Tissues Investigated. Hydrogen bonding in calcium-de-
ficient apatites was investigated by infrared spectrophotometry in work sup-
ported in part by the U.S. Public Health Service. A direct correlation was
found between the number of calcium ions missing per unit cell volume,
obtained by chemical analysis and refractive index measurements, and the
hydrogen bond content.

Dimensional Changes in Dentures. A study sponsored by the
American Dental Association and the Federal dental services established
that the dimensional changes of dentures in service are too small to be of
clinical significance. In the investigation more than 200 dentures were

616114 o — 61-

105

measured, some over a period of six years. They had been made of 12 dif-
ferent types of polymers processed by a variety of currently used methods.
Acrylic resin dentures processed with simple conventional equipment, em-
ploying compression molding, were just as accurate and as dimensionally
stable as dentures made with other types of resins using complex and costly
equipment.

Dental Amalgams from Spherical Particles. The particle size of
the alloy (Ag-Sn-Cu-Zn) used in making dental amalgams was investigated.
independently of other variables, in a study sponsored by the American
Dental Association and the Federal dental services. A standard alloy corn-

Data were obtained on the mechanism of polymerization and on the chemical
changes induced in polymers by ionizing radiation. Here free radicals pro-
duced by ultraviolet radiation are studied by electron spin resonance
(page 105).

106

position was used in the form of spherical particles produced by spray
atomization. The particles were separated into eight different sizes, the
smallest 1-4 microns and the largest 105-150 microns in diameter. Par-
ticles from 15-50 microns diameter exhibited the highest strength of all those
studied. The study showed that an alloy in this spherical shape produces
an amalgam equal or superior to those in current use, and offers a new
approach to the control of critical amalgam properties, such as early strength,
setting time, and flow, and promises major advances in the simplification of
manufacture.

2.3. SPECIAL TECHNICAL SERVICE

PROGRAMS

2.3.1. APPLIED MATHEMATICS

The Bureau's applied mathematics facility conducts basic and applied
research and renders advisory services in various mathematical fields. These
services are available to other Government agencies as well as to the Bureau's
staff. Modern computing equipment is used by the facility in support of its
program.

During the past year the Bureau emphasized activities in statistical and
numerical analysis, mathematical physics, and operations research. Exten-
sive assistance was rendered in these areas and in digital computation.
Special attention was given to problem formulation and analysis in order
to select and develop numerical methods for the solution of problems in
engineering and the physical sciences, utilizing both automatic and non-
automatic computing machines. An appreciable share of the mathematical
program was devoted to government problems of business management and
operation, sometimes called data-processing problems. Significant progress
was achieved in the exploration of the utility of modern digital computers in
the mechanical translation of scientific publications, for which there is a
continuing urgent need.

As in previous years, the Bureau's applied mathematics program was
strengthened by the active interest and support of other Government agencies.
The Office of Naval Research and the USAF Office of Scientific Research
supported fundamental and applied research in numerical analysis and
mathematical physics, respectively. The National Science Foundation con-
tinued to support the compilation of a handbook of mathematical functions
and mathematical research related to information retrieval. The study of
mechanical translation of scientific publications was supported by the U.S.
Army Research Office and the Office of the Chief Signal Officer, U.S. Army.

Combinatorial Analysis. Work continued in combinatorial analysis,
a branch of mathematics concerned with the arrangements of finite sets of
objects. It was applied to the selection of the best pattern of linkages in
transportation or communication networks, in the determination of the most
efficient method for encoding messages to provide automatic correction of

107

possible transmission errors, and in the design of experiments to maximize the
useful information obtained from a given number of measurements.

Eigenvalue Theory, The determination of eigenvalues for operators
is a central problem in mathematical physics which frequently involves con-
siderable numerical difficulty. A method of "generalized special choice"
has been developed for determining lower bounds to the eigenvalues of self-
adjoint linear operators. Numerical results carried out for the anharmonic
oscillator are satisfactory even when perturbation theory fails. The method
has also been used to estimate the eigenvalues of the spheroidal wave equation.
The numerical results obtained by this method were found to be excellent in
regions where difficulties were experienced with other procedures.

Matrix Theory, Various schemes were investigated for the solution of
matrix eigenvalue problems. Extensive research continued in the develop-
ment of techniques for obtaining the characteristic roots, the determinant,
and the F-condition number of matrices. Several new results in doubly
stochastic matrices have been obtained through the exhibition of the per-
manent as an inner product in a suitable space. Inequalities were derived
which lead to new bounds for the determinants of nonnegative Hermitian
matrices.

Approximation Theory. Research in approximation theory was em-
phasized because of its fundamental importance in numerical analysis. Ex-
tensive investigations of best approximation by nonlinear families were con-
tinued. A study was conducted concerning the approximation to convex
functions by means of convex polynomials and trigonometric polynomials.
The results contain some explicit constructions and estimates of accuracy.
Tchebycheff approximation by rational functions was investigated, with
emphasis on the computational aspect. Significant research on infrapoly-
nomials and their generalizations was also performed.

Numerical Experimentation. In areas of numerical analysis where
no theory exists or existing theory is merely suggestive, numerical experi-
mentation may provide insight into a method of problem solution. Such
experiments were performed in the numerical solution of nonlinear partial
differential equations. The partial differential equation determining the
pressure distribution in a gas-lubricated bearing was studied. The final
aim, once a method of solution was found, was to compute a set of design
curves for such bearings. Also, a system of three nonlinear, ordinary
differential equations arising in a study of the internal structure of stars was
investigated.

Machine Translation. Further progress was made on the automatic
Russian language translation scheme being developed by the Bureau. In
contrast with other machine translation projects, the Bureau project is
characterized by emphasis on syntax in the conventional sense and by a
system of predictions. A Russian word in a sentence "predicts"' certain
other grammatical forms; for example, a transitive verb predicts a direct
object.

A significant innovation has been the development of a procedure called
profiling," by which clause and phrase boundaries are recognized mechani-

108

cally before the detailed analysis by use of predictions begins. This tech-
nique will greatly increase the speed of translation through the proper
placement of subject and predicate in the syntactic analysis.

Mathematical Tables, The main concentration in mathematical tables
during the year has been on the completion of the Handbook of Mathe-
matical Functions. All chapters of the Handbook now exist in manuscript
form. A modest amount of revision of expository text and updating of
bibliographies remain. The Chapters in press comprise about one-quarter
of the volume.

Digital Computation, Digital computers were applied in both the
scientific and data processing fields. Scientific computing was centered
about measurement and calibration, i.e., primarily concerned with problems
on gage blocks, thermometers, bead sizing, heat pump capacity, transistor
aging, etc. Problems such as those arising in studies of crystal structure,
the thermodynamic properties of gases, spectrum analysis, and colorimetry
also required extensive computing techniques. Significant computations
were performed on problems related to radiation patterns of antennas, light
scattering, heat transfer in crystals, and the radiative envelopes of model
stars. Important problems in data processing included the assignment of
radio frequencies, traffic studies, mathematical investigations related to
postal operations, analysis of electrocardiograms, airline traffic surveys, and
the simulation of military engagements.

Extensive research was continued in the field of automatic programing,
where the primary objective is to render easy, fast, and inexpensive com-
munication between electronic computers and human users. The Bureau
pursued this objective with direct practical applications as well as through
research and long-range development. The Black Box Computer — a tool
devised to speed a problem from originator to machine — was improved and
its applications expanded. By use of this tool, Bureau laboratory workers
can prepare their problems for direct introduction into electronic computers
to produce least-square fits, numerical integration and interpolation, com-
pilation of physical tables, evaluation of certain desired statistics, such as
the mean or the standard deviation, etc.

The Bureau has performed research in the area of artificial languages
and their translation by machine. It participated during the year in the
establishment of programer-oriented languages — ALGOL for scientific appli-
cations and COBOL for business or data-processing problems. Significant
contributions were made, also, to the program on standardization of symbols,
languages, and equipment of the Office Equipment Manufacturers Institute.

Experiment Designs, Work on the mathematics of experiment de-
sign resulted during the year in the substantial revision and preparation for
publication of the "catalog" of fractional factorial designs for the 2mSn
series developed during the preceding year in preliminary form. A special
class of "weighing" designs of the fractional factorial type was studied.
These designs approach the classical weighing designs with respect to the
small numbers of observations required, but still permit identification of

109

two-factor interactions and thus are particularly appropriate for use in ex-
periments on the determination of fundamental physical constants. In addi-
tion, they are applicable to the evaluation of routine calibration and testing
procedures. Explicit construction and "cataloging" of a series of magic rec-
tangles for use as trend-elimination designs were accomplished. These
rectangles provide orders for running the "treatment" combinations in a two-
way classification so that comparisons of the resulting "main effects" of
the respective "treatments" are not upset by linear trends or drifts in the
measurements. A special operational calculus for symmetrical and asym-
metrical factorial arrangements was developed.

Life Testing and Reliability. The intensive investigations of the
measurement of reliability conducted by the Bureau were summarized to
show the possible weaknesses of current life-testing procedures being applied
when the assumptions on which they are based are not valid. New and im-
proved results were obtained, including excellent approximations to the dis-
tribution of a sum of Weibull-distributed random variables and to the
OC-curves and average-sample-size expressions for sequential tests based on
sums of Weibull-distributed random variables.

Probability and Mathematical Statistics. Studies in probability and
mathematical statistics took various forms. Work was resumed on the NBS
tables of power points of the noncentral F- and X2-distributions. A detailed
numerical investigation was initiated of properties of a special family of
probability distributions derived from the uniform distribution on (0, 1)
by a transformation suggested by J. W. Tukey. Information theory was
applied to the analysis of a four-way contingency table. The fourth in a
Bureau series of selected bibliographies of statistical literature for the period
1930-1957 was completed.

Mathematical Physics. Research in mathematical physics emphasized
the formulation of mathematical theories basic to the development of theoret-
ical physics and engineering science. Investigations included research in
the kinetic theory of plasmas and magnetohydrodynamics. in which the
previously developed theory for homogeneous plasma was generalized to
include the long-range collective behavior, the effect of memory in oscilla-
tions, and the expansion wave problem in neutral gases.

Investigations concerning satellite orbits were continued. Emphasis was
placed on the central problem of satellite astronomy, namely, the determina-
tion of the motion of an artificial satellite around an axially symmetric but
oblate planet. The method developed reduces the relevant Hamilton-Jacobi
equation to separable form, and provides for the application of well-known
techniques in successive approximation to the problem of satellite motion.

Other work in mathematical physics included studies of Brownian motion,
as governed by the Chapman-Kolmogoroff functional equation: elliptic
boundary-value problems, in which important bounds for the deflection of
elastic plates were derived; the deflection of circular plates with radially
varying thickness under a radially symmetric traverse load and edge condi-
tions; and the flexure of elastic beams.

110

Operations Research, General areas of investigation during the year
included game theory, graph theory, weapon simulation, Boolean functions,
and mathematical models of distribution networks.

The problem of optimal frequency allocations for a network of radio
transmitters is similar to that of finding a minimum point-cover of a linear
graph. Graph-theoretic algorithms were investigated. A significant develop-
ment was that of a general algorithm, suggesting characterization for optimal
coverings of a set, providing promising alternatives to known algorithms, and
specializing to the minimum point-cover problem.

Three major areas were explored in connection with the analysis of mathe-
matical problems related to postal operations. These areas were: (1) a long-
range study of mathematical models of distribution networks, with a view
to optimizing the location of distribution centers and the degree of system
centralization; (2) determination of the appropriate parameters for a
specified mail-sorting device; and (3) studies concerning procedures in
existent, partly automated post offices.

Other significant activities in operations research during the year included
the analysis and computer simplification of Boolean functions ( important in
network and circuit theory), the analysis and simulation of missile system
operation, a study of optimal radar site distribution, and the analysis and
simulation of electronic countermeasures.

2.3.2. DATA PROCESSING SYSTEMS

The Bureau has been conducting a broad program of research and develop-
ment in analog and digital technology and in application techniques needed
to foster effective use of data processing systems by the many agencies of the
Government. A major purpose was to extend the areas of application beyond
conventional "paperwork" as well as to expedite the data handling problems
of the experimental sciences and the storage, search, and retrieval of infor-
mation. The Bureau's data processing systems laboratory acts as a centrally
available technical facility for providing assistance and advisory services
for such purposes within the Bureau and to other government agencies.

Some present areas of activity include research, design, and evaluation of
improved circuitry; logical organization of data processing and control sys-
tems; automated collection, transmission, and presentation of experimental
data; and techniques for machine processing of syntactic and graphic forms
of data. Of particular significance is the continued expansion of the pro-
gram of assistance to the Bureau's own research laboratories in identifying
problem areas particularly adaptable to automatic data processing techniques
and demonstrating the feasibility of preparing experimental data in acceptable
form for input to and output displays from a central high-speed automatic
data processing facility. The range of data processing applications both
for NBS and for other government agencies increased materially during the
past year.

Ill

The PILOT data processor, now nearing completion, will provide a highly flex-
ible research facility for new and unusual Government data processing prob-
lems (page 112).

PILOT Data Processor. The engineering design and physical struc-
ture of the NBS PILOT Data Processor, a highly flexible research tool de-
veloped for investigating new and unusual data processing problems for the
Government, was completed. Power distribution, clock distribution, circuit
protection, and logical wiring for all parts of the machine were installed.
The secondary diode-capacitor memory is already functioning as a part of
the PILOT system, while the completed primary diode-capacitor memory is
ready to be mated to the central machine. Performance tests were completed
on the logical wiring of the system and on 7,000 individual stages of the
system.

The peripheral equipment presently attached includes an automatic type-
writer, magnetic wire handler, magnetic tape handler, and high-speed paper
tape reader. Initial service programs were prepared, and specifications
were established for the preliminary compiler for the main computer. The
first set of training courses in both programing and maintenance and
operation was conducted in preparation for routine operation.

Technical Assistance for Data Processing, The continuing aid and
assistance to the laboratory operations throughout the Bureau led to the
identification of a considerable number of potential areas for automatic data
recording and processing, many of which had special data-conversion prob-
lems. Technical assistance was provided through study of the problem to
determine whether analog and/or digital techniques were applicable and

112

through demonstration of the feasibility of such applications. Additional as-
sistance was given in the form of design and development of special data-
logging equipment, some of which was constructed by the "user" laboratories
with advice in the utilization of packaged circuitry provided by the data
processing systems laboratory in order to convert the data to input form
acceptable to the computer.

Typical problems on which assistance was provided included gas analysis
by infrared spectrometry, plasma traverse, transmission of data from radia-
tion physics, coulometric titration, heat transfer by radiation, concentration
of near-saturated solutions, separation of signals from noise, radial distribu-
tion of plasma properties, search of atomic nuclei in crystal structures, model
loop for process control with dead time, stability constants of complex ions,
nuclear reactor transients, probability of convoluted probability functions,
theory of reflection from metallic surfaces, processing metallurgical photo-
micrographs, plotting of continuous curves by interpolation of discrete data
on magnetic tape, storage and examination of 1,000 points in the focal plane
of a lens, and handling of data from an electron paramagnetic resonance unit.

Components and Techniques. The development of faster, more com-
plex, and more reliable computers and data processors has led to the study of
new components and further investigation of existing ones. Measurement of
the properties of these components is fundamental. Several significant con-
tributions were made to the theoretical analysis of solid-state semiconductor
devices operating as circuit elements.

A large-signal junction transistor equivalent circuit and switching theory
study was completed. This study produced a new large-signal junction tran-
sistor equivalent circuit that is valid for all modes of circuit operation. The
physical charge-concept approach to semiconductor devices was bridged
mathematically to the area of device application, resulting in nonlinear dif-
ferential equations that could be solved by graphical, analytic, and computer
techniques. These equations made possible analytic solution of modes of
junction transistor operation which were previously untractable. The use of
new time domain measuring techniques was incorporated into the study as
a means of evaluating elements of the equivalent circuit. The study also
resulted in a characterization of the transient input base current of the
junction transistor for all driving conditions. The static base-to-emitter
voltage-current characteristic and a unique time constant factor were shown
to be the principal data required for the large signal switching analysis.

A tunnel diode large-signal simulation study was undertaken which in-
volved the development of an analytic approximation to the static voltage-
current characteristics of the tunnel diode that displayed the required nega-
tive-resistance region. A complex second-order nonlinear differential equa-
tion and techniques for its solution by analog computer and graphical analy-
sis methods were developed. These equations are of considerable value in
determining the large-signal switching response of the tunnel diode in digital
circuitry.

113

The investigation of high-speed transistor flip-flop circuits was initiated.
Several basic configurations such as current-controlled, collector-clamped
(nonsaturating) , and saturating types are under investigation.

Research was continued in determining the relation between properties of
films which show promise as very fast memory and switching elements and
their structure and chemical composition. Major effort was devoted to
developing a fast transmission line magnetization reversal tester and an ac-
companying sampling oscilloscope system, perfecting the thickness-measuring
techniques, and making microchemical analysis of the films. The test set-up
for measuring the fast magnetization reversal consists essentially of a parallel-
plane transmission line or wave guide operating in the TEM mode.

Experimental study of the high-speed partial switching behavior of fer-
rite memory cores for use in the design and development of improved digi-
tal circuits in advanced digital computing and information-handling systems
and for performing switching and memory functions was continued. A
report covering the mathematical analysis of a transistor-magnetic-core digi-
tal circuit was completed. The concepts and analytical methods presented
in this report have general application in the design of very high speed
digital circuits.

Automatic Data Retrieval, Under the sponsorship of the Patent Of-
fice and the National Science Foundation, investigation continued leading to
the development of automatic programing systems for processing informa-
tion contained in collections of documents, through syntactic analysis of
both natural language text and associated pictorial information. A se-
quence of grammars was written for a fragment of English concerned with
simple pictorial subjects. Programing procedures were developed that en-
able a linguist to test the grammars for adequacy by producing samples of
sentences with their assigned syntactical analyses. In addition, theoretical
models for language grammars and for picture-processing mechanisms were
explored by both simulation and analytical study. Results from automata
theory were applied to classification of the grammar model used in the
linguistics research, and mechanical-theorem-proving literature was searched
for results usable for formal inference in the development of a general-
purpose research tool, such as a Picture Language Machine, which will pro-
vide the capability for exploring more complex problems in pattern
recognition and linguistic analysis.

Development of Information Selector, The design of an improved
model of an information selecting device for retrieving information from
large files of documents stored on coded microfilm was developed for the
Navy Department's Bureau of Ships. This new model of the rapid selector
provides increased speed and reliability, simplicity of film handling, multi-
word selection, and programed logic control of output. An improved input
preparation device for producing original coded master film was also de-
veloped as part of the system.

Special-Purpose Digital Computer (AMOS IV), Under a program
sponsored by the Weather Bureau, a special-purpose digital computer,

114

AMOS IV, was developed as the central element in an automatic weather
station to collect and reduce weather data prior to transmission. During
the past year this prototype has undergone extensive testing and modifica-
tion. A number of diagnostic routines were written and checked on the
machine; circuitry for pre-processing signals of the variety produced by
weather-sensing elements was developed and tested insofar as practical; an
oscilloscope was added for displaying the contents of any memory channel
and for displaying characters or graphical information; and new circuitry
for counting against a variable time base was included for versatility. In
addition, a closed circuit teletype line was established between the NBS
laboratory installation and the Weather Bureau, with low-speed printers
connected at each end. Several low-speed messages were transmitted over
this line. The Weather Bureau began constructing additional machines
similar to the AMOS IV, under NBS technical guidance. Training of
Weather Bureau personnel in the use of digital and transistor circuitry and
in computer programing has continued in conjunction with the system
development.

Data Source Automation. An automatic data-recording system was
developed for the Navy Bureau of Supplies and Accounts in connection with
the preparation of Naval supply messages for ordering Federal stock items.
The envisioned system consists of the format control and preparation of
messages for teletype transmisison on punched paper tape, and catalog item
selection and transcription of descriptive catalog information. The initial
system will contain an operator's panel for hand selection of the variable
information with visual display of message before printing out. The ob-
jective is to minimize the number of errors in the Navy supply system orig-
inating in the initial process of ordering stocks. The supply catalogs con-
tain approximately one and one-quarter million items in 76 major categories
printed on one-quarter million pages.

Weapons Systems Evaluation, Under the sponsorship of the Bureau
of Naval Weapons, continuing assistance was provided on computation,
simulation, and data processing problems as applied to weapons systems
evaluation and test range instrumentation for the Pacific Missile Range. A
study was completed of the real-time computation system to provide on-line
computation of test missile trajectories, some vehicle control functions, and
tracking acquisition aids for remote tracking installations with extremely
fast repetitive computations of impact points for range safety purposes. This
study led to the preparation of specifications, evaluation of initial phase de-
signs submitted by contractors, and review of the final multicomputer
design. In addition, an advanced flexible system was planned for handling
various types of multichannel telemetry inputs either on-line or post-flight,
at very high speed with computer control of data format, location, and
sampling rate. This was a cooperative effort with the Naval Air Develop-
ment Center.

Attention was also directed to methods of specifying performance of very
fast, very accurate analog-digital conversion systems and the necessary lab-

115

oratory instrumentation for measurements. A facility for very high ac-
curacy static measurements was established, and three production types and
one developmental type of analog-to-digital converter are being evaluated.

Airways Systems Analysis. Detailed studies of the information con-
tent of a future air traffic control system utilizing large-scale automatic data
processors were continued under Federal Aviation Agency sponsorship. Pre-
liminary design specifications of the display and control requirements for
an adaptive controller-equipment module (CEM) were developed. Concur-
rent with logical design studies, hardware implementation of a breadboard
system was planned and initiated.

Pictorial Data Processing. Under the sponsorship of the Naval Train-
ing Device Center, research efforts were continued in developing methods and
techniques for scanning aerial stereophotographic information and, in writing
computer programs, for translating this information into elevation profiles.
A three-dimensional model with relatively small black and white areas was
photographed, scanned, and transcribed into SEAC; and computations of
altitude and planimetric position were made that were within the accuracy
of the scanner resolution. In addition, processes for the removal of objects
outside the given overlap regions and for producing outlines have been coded.
The programs for deriving photogrammetric data from pictures containing
relatively large areas will continue to be investigated in the hope that similar,
possibly identical, programs will be applicable to continuous-tone photo-
graphs after image processing.

Psychological Data Processing. The system previously developed at
the Bureau for processing electrocardiograph data was redesigned to meet
the need of the Air Force Office of Scientific Research for a low-cost system
for processing psychological data. As finally constructed, the new system
provides for scanning and recording ten analog voltages in digitized form on
magnetic tape. In addition, a translator is provided to change the output
from binary to binary-coded decimal. This experimental equipment was
sent to the University of Georiga, where it will be put into operation.

Data Processing Applications. The mechanized NBS personnel data
recording and reporting system, including file maintenance and the produc-
tion of 44 regularly recurring personnel reports and one budget report, was
put into routine operation. Several new reports were added to the system
and approximately 15 special on-request reports were also generated during
the year. Several other government agencies have expressed considerable
interest in the project (Tennessee Valley Authority, Railroad Retirement
Board, General Services Administration, Bureau of the Census) .

The feasibility study for determining the applicability of automatic data
processing techniques to certain operations of the Federal Communications
Commission was concluded. Assistance was given to the Public Health
Service in developing mechanized collection of information on radiological
hazards from food and water supply, medical and dental diagnosis and
therapy, atmospheric fallout, industrial and research laboratories, and other

116

sources, including catastrophic release of hazardous radiation. The Division
of Radiological Health, Public Health Service, was given assistance in
analyzing equipment and methods to be used in the determination of the
amounts of specific radioisotopes from the gamma-ray spectrum readings
obtained on food samples. In addition, equipment was designed and con-
structed for collecting data from a gamma spectrum analyzer along with
identifying comments from a manual keyboard. It is planned to use this
same equipment to provide on-line operation of the gamma spectrum analyzer
with an electronic computer.

A final report was submitted to the Research Grants Division, National
Institutes of Health, in connection with a preliminary study of the applica-
bility of automatic data processing methods and techniques to more effec-
tively maintain and select information concerning their research grants
program.

The Public Housing Authority constantly reviews a tremendous volume of
reports of eligibility for continued occupancy of low-rent housing. Con-
tinued advice and assistance were given in programing, debugging, and run-
ning various statistical routines.

Under the sponsorship of the Interstate Commerce Commission, an explora-
tory investigation was initiated of the major objectives, functions, and oper-
ational units of ICC to determine feasibility of applying automatic data
processing techniques to selected activities and operation. Several short-
range projects and several long-range tasks with substantial potential gains
in effectiveness or savings of funds were identified, and work on the next
phase of this study was outlined.

The feasibility study undertaken for the Maritime Administration to deter-
mine the use of automatic data processing techniques and equipment in
support of their regulatory functions, including complex subsidy determina-
tion and marine engineering calculations, was terminated. The routine paper-
work associated with the consideration of subsidies for the construction and
operation of ships was analyzed, and it was concluded that mathematical
calculations relating to the characteristics of ship hulls and propulsion equip-
ment could be successfully transferred to a large-scale computer for routine
operation.

Preliminary investigation of the objectives, functions, and operational
units of the Office of Technical Services, U.S. Department of Commerce, was
initiated to determine the feasibility of applying automatic data processing
techniques to its activities and operation. OTS collects scientific literature
and reports of Government-sponsored research, reproduces them, and sells
them at the cost of printing and handling to scientific and industrial labora-
tories, private individuals, and business enterprises. In addition, OTS pre-
pares catalogs and indexes, and conducts searches (for a fee) of technical
documents originating in Government agencies and in the offices of their
contractors. A general survey of the operations of each of the organizational
units of OTS was begun as the first step in a detailed analysis of the functions
of this agency and the demands made upon it.

117

Research Information Center. The collection and organization of
literature and bibliographic references covering a wide range of interests in
information storage, selection, and retrieval continued for the Research
Information Center and Advisory Service on Information Processing, which
is under joint sponsorship of the National Science Foundation and NBS.
During the past year the collections of the pertinent literature, references,
and other related material have more than doubled. Abstracts and/or com-
plete texts are now available for over 5,000 literature items in the several
fields of interest.

Work continued on a systematic glossary of terms, and specialized lists
of workers active in the fields of character recognition and the theory of
automata were selected from the files. In addition, specialized bibliographies
were prepared and checked in connection with the preparation of several
state-of-the-art reviews pertinent to the subject areas of information storage
and retrieval systems and of mechanized translation. Two state-of-the-art
studies — a survey of the present status of automatic character recognition
and a guide to the literature of automata theory with special reference to
potential applications in mechanized information selection and retrieval
systems — were prepared for publication. The Center continues to give
bibliographic and other services to cooperating workers in the field, govern-
ment agencies, and interested correspondents.

Developments in Automatic Mail Sorting. The Bureau continued
its assistance to the Post Office Department Office of Research and Engineering
in applying automatic equipment and data handling techniques to the im-
provement of mail-sorting operations. A program was developed for testing
and demonstrating prototype letter sorting equipment, and for emphasizing
the experimental use of the installation to obtain human factors data and
basic statistical data now lacking. In preparation for this program, manual
sorting schemes or procedures were rewritten and further adapted for use
with the code-sort equipment. These rewritten schemes were designed to
utilize the flexibility of the code-sort equipment and to serve as a model for
future sorting studies or new schemes. In addition, the revised sorting
schemes were translated into a punched card format, and the code-sorting
schemes are continually updated to reflect changes in the manual schemes
resulting from changes in transportation schedules, adjustments to carrier
routes, etc. A computer program was developed to assist in the analysis
of possible future coding procedures, and an attempt was made to develop
a computer program that selects "optimal" paths for routine mail. This is
a variation of the well-known "shortest route problem" and is expected to
yield procedures for evaluating new plans such as the "National Integrated
Postal Service Plan." The operations of two new Post Offices that were
designed to utilize the present state of the postal mechanization art were
evaluated. The network studies of the sorting and transportation problem in
its entirety were begun.

Mechanization of Patent Searching. Major emphasis in the co-
operative program with the Patent Office for implementing the mechaniza-

118

tion of composition-of-matter patent search operations was devoted to plan-
ning, developing, and debugging large-scale data preparation and data
checking routines. These routines are required in the preparation of error-
free library files of disclosure information for use in trial runs using diverse
types of realistic questions. The pactical applicability of chemical search
strategies such as those incorporated in HAYSTAQ can then be determined.
It is hoped that these experiments will result in meaningful statistics as to
the most frequently recurring errors and the variation in incidence of error
among individuals. Preliminary research on methods of file organization
have also been in progress, the objective being the development of powerful
screening methods for increasing search efficiency.

Simulation of Traffic Flow, At the request of the Bureau of Public
Roads, which is concerned with the design of more efficient highway signal
systems, a program for simulating municipal traffic flow by means of high-
speed automatic data processing and display equipment was completed. The
program prescribes the rules for movement of randomly generated cars along
the several blocks of 13th Street NW, Washington, D.C. between Euclid
and Monroe Streets. A scanning program spots car positions and writes
the coordinates on a magnetic tape. A computer using this information
projects the car positions onto an oscilloscope and actuates a camera to
take pictures of the successive position displays. Detailed tables that catalog
all vehicles as they enter the test course, clock and count the vehicles as they
pass a key intermediate point, and finally check out the vehicles at the end
of the course noting their running time, are produced as a byproduct for
further analysis. Other information furnished includes the type of vehicle,
speed, and lane use. These tables furnish an abundance of quantitative data
for measuring and evaluating the performance of the model.

2.3.3. INSTRUMENTATION

Measurement precision depends on two factors: The natural limitations of
the measurement process, and the realizable performance of measuring in-
struments. Under a broad instrumentation program, the Bureau investi-
gates both of these factors to improve its measurement capability in research
and calibration activities. The fundamental properties and limitations of
instruments, their components and materials, as well as measuring, record-
ing, and signal-processing methods, are studied. The program also includes
study of basic phenomena that may be usefully applied to instrumentation.

Modern instrumentation frequently uses electronic techniques, even when
the initial measurement problem is not fundamentally electrical. The elec-
tronic program includes investigation of the materials used in vacuum and
semiconductor electron devices; study of the characteristics and capabilities
of electron devices themselves; the development of improved electronic in-
struments to meet the needs of the Bureau's research program; and a variety
of projects undertaken for other Federal agencies.

119

Right: The anchored, unmanned, automatic
weather station, "Nomad," developed for the
Navy, was the first automatic weather station
to detect formation of a hurricane. Above:
NBS engineers also helped the Navy to de-
velop and set up a chain of automatic
weather stations in the Antarctic (page 120).

Mechanical instrument activities include development of standard hy-
grometers and humidity generators, calibration methods for pressure and
displacement transducers, and study and development of instruments needed
specifically by other Federal agencies.

To avoid duplication of scientific research effort, it is necessary to keep
abreast of the instrumentation art. The Bureau therefore maintains an
extensive reference file of literature on instruments and measurement
methods. The file itself is designed so that its data can be retrieved partly
by mechanical means.

Meteorological Instrumentation. The Bureau developed an anchored
automatic weather station, and during the year weather information was
telemetered from the station after it had been placed in a remote location
on the ocean surface. The station was called NOMAD (Navy Oceano-
graphic Meteorological Automatic Device) . It was the first such station
to be anchored successfully for a substantial period in more than 11.000
feet of water. It also was the first anchored automatic station to detect
formation of a hurricane and alert weather observers on land. A special
storm-sensing device contributed to this achievement. The station was de-
veloped as part of the ocean test and evaluation program, begun in 1957
for the Bureau of Naval Weapons, with NBS responsible for technical
direction.

120

Antarctica Assistance. At the request of the Bureau of Naval Weap-
ons and Navy Task Force 43, NBS engineers participated in Operation Deep-
freeze 60 and Operation Deepfreeze 61. During the former a network of
automatic weather stations was established on the Ross Ice Shelf, and along
the coasts of Ross Sea and Rellinghausen Sea. The stations were developed
by the Naval Research Laboratory, based on a World War II development
at NBS.

During Operation DF 61 a more extensive network of stations was estab-
lished on the Ross Ice Shelf and the Polar Plateau. Several prototype
weather stations were used operationally for the first time. The data col-
lected and transmitted automatically by these stations aided Navy meteor-
ologists materially in forecasting weather for flights to, from, and within the
Anarctic continent.

Hygrometry. The Bureau's basic reference for humidity measurement
is a gravimetric hygrometer that determines the moisture content of gases
on an absolute basis. All known sources of error for this instrument were
analyzed and evaluated. As a result, it is estimated that the absolute hu-
midity of a gas sample now can be measured with a standard deviation of
4 parts in 104.

Upper-atmosphere ballon flights were made from the Bureau with the
NBS fast-responding electric hygrometer element, used with an improved
a-c radiosonde circuit, to study performance of the hygrometer under
field conditions. This work was partly supported by the Bureau of Naval
Weapons. The experiments, which are still in progress, indicate that large
humidity gradients, discrete humidity changes, and humidity microfluctua-
tions can be observed. The element also was used on the Office of Naval
Research high-altitude, manned balloon flight (Strato-Lab High No. 5) for
measuring atmospheric relative humidity throughout the flight.

FOSDIC. An advanced type of Film Optical Sensing Device for Input
to Computer (FOSDIC) is being developed for the Weather Bureau, where it
will read and collate records of weather data prior to electronic data process-
ing. The new FOSDIC will examine microfilmed punch cards being prepared
by the Weather Bureau in its existing FOSDIC program. Features of the
new machine include programed capability for detecting illogically punched
or damaged data cards and ability to monitor its own errors and malfunctions.
Alternative punch-card or magnetic-tape outputs are provided to ensure com-
patibility with both present and proposed data systems.

Telemetering Pickups. The Bureau investigates the characteristics
of telemetering transducers, and methods for their measurement, as part of a
program sponsored jointly by the Bureau of Naval Weapons, the Army
Ordnance Corps, and the Air Force. During the year, a facility was acti-
vated for wave analysis of transducer responses excited by a shock tube. The
resonant frequencies of pressure transducers can be ascertained with this
equipment, and the resulting information determines the upper frequency
limitation on faithful reproduction of pressure transients. The useful fre-
quency range of the analyzer is 1 to 100 kcs.

616114 O— 61 9 121

During the year, a pneumatic stepfunction pressure calibrator, which gen-
erates known pressures in the range from 2 to 100 psi, was completed. The
generated stepfunction attains an amplitude constant to within ±2 percent
within 15 milliseconds. The final pressure is known to within ±0.1 psi.

Electronic Fault Location, A program, sponsored by the Navy Bu-
reau of Ships, is underway to develop techniques for measuring rapidly the
performance of electronic circuits in working equipment. Such equipment
often is composed of electric subassemblies, or modules; and a method is
sought to enable the semiskilled maintenance man to quickly locate and re-
place any defective module. Simple procedures using bridge methods are
being worked out for testing amplifiers, waveform generators, and timing
circuits. A catalog of these techniques will be prepared.

Electron Emission of Thermionic Cathodes, Carbonates of barium,
strontium, and calcium were deposited on nickel cathode surfaces by an im-
proved electroprecipitation process. This is an alternative method for
applying the emissive material to the cathode of electron tubes. The method
is a simple plating procedure using a filtered solution of the bicarbonate in
water. Its principal advantage is ultracleanliness, yielding coatings of pure
carbonates uncontaminated by the ball-milling, organic vehicles, and soluble
salts involved in conventional techniques. The process can be adapted for
various cathode shapes — cylindrical, plane, conical, etc. — and the small
laboratory now can maintain control of coating density and texture as well
as purity.

Because of hydrogen evolution at the cathode, mechanical motion of the
electrolyte over the cathode surfaces is essential. An electrolyte tempera-

Microcite, a close-coupled searching machine developed for use with the NBS
punched-card (peek-a-boo) instrumentation index. The operator can locate
references, view abstracts on the screen at the top, and make copies of the se-
lected abstract automatically (page 123).

122

ture of approximately 10 °C is desirable. The throwing power is poor, so
that any simple means is effective for surface masking.

Vapor Pressure of Alloys. A vacuum microbalance with a sensitivity
better than one microgram was used to determine vapor pressure of the minor
constituent in nickel-base alloys. Alloys of this type are important in man-
ufacture of electron tubes. Samples containing approximately 0.1 percent
of magnesium, aluminum, and titanium were measured successfully. For
satisfactory measurement, the impurity diffusion rate must exceed its loss
at the alloy surface, and a vacuum pressure less than 10~9 torr is needed to
prevent combination of the impurity with gas at the surface.

Instrumentation Reference Service. A searching machine was de-
veloped for use with the punched-card (microcite) instrumentation index.
The machine enables an operator to identify quickly all information in the
index on a particular instrumental or measurement subject, Meanwhile,
simple methods were developed for replicating the punched cards used in
the Bureau's reference index. The same techniques are expected to be useful
in performing information searches based on logical sum and logical
difference.

Technical Communication. Communication among scientists and or-
ganizations is an effective means for avoiding needless duplication of effort.
A study of the state of such communication, relative to the electronic research
program of the Federal Government, was made for the Senate Subcommittee
on Government Reorganization and Internal Organizations of the Senate
Committee on Government Operations.

2.3.4. RADIO PROPAGATION

The Central Radio Propagation Laboratory, located at Boulder, Colo.,
has the primary responsibility within the U.S. Government for collecting,
analyzing, and disseminating information on the propagation of radio
waves at all frequencies along the surface of the earth, through the atmos-
phere, and in outer space. To carry out its responsibility, this Laboratory
conducts research on the nature of radio waves and the media through which
they are transmitted, the interaction of the waves with media, and the nature
of the radio noise and interference effects. A network of field stations is
operated from the Arctic to the tropics, and data are exchanged with other
laboratories throughout the world. A newly established mathematics group
is responsible for mathematics and computational procedures at the Boulder
Laboratories. To assist this program a large transistorized computer was
acquired, and is now being used in the solution of such problems as propa-
gation of VLF-LF radio waves, the true height of the inonosphere, radio ray
tracing, ionospheric mapping, and cryogenic properties of materials. The
work of the Laboratory is divided into four areas: Ionosphere research and
propagation, radio propagation engineering, radio communications and sys-
tems, and upper atmosphere and space physics.

123

IONOSPHERE RESEARCH AND
PROPAGATION

The Bureau conducts and coordinates basic research on the propagation
of radio waves as affected by the ionosphere and on the special factors which
can give rise to large departures from the normal behavior; conducts basic
research on the nature of the media through which these radio waves are
transmitted and the interaction of radio waves with the media ; prepares pre-
dictions of radio wave propagation and warnings of disturbances; acts as
a central repository for data, reports, and information in the field of ion-
ospheric radio wave propagation; and provides consultation services on the
characteristics of the ionosphere and on radio wave propagation to other
government agencies and industry.

Javelin rocket which carried an ionosonde to an altitude of 1,000 kilometers.
For thirteen minutes, the ionosonde made topside soundings of the ionosphere.
The experiment was made to test the sounding system for the fixed-frequency
satellite topside sounder to be orbited in 1962 (page 127).

124

VLF Phase Stability Studies. Propagation characteristics of phase
stabilized transmission in the very low frequency (VLF) band of the radio
spectrum are studied to provide data on the state of the lower ionosphere.
A record of the phase and amplitude of a VLF transmission discloses the
normal variation in the phase resulting from changes in the effective height
of reflection of the ionosphere from day to night. Abnormal variations
in the phase of a VLF signal are observed to accompany both magnetic
storms and solar flares (Sudden Phase Anomalies). An unusually large
Sudden Phase Anomaly (SPA), produced by a solar cosmic ray flare, was
observed at 1030 UT, 4 May 1960 on the record of the 16 kc/s GBR trans-
mission from Rugby, England, to Boulder, Colo. The high energy cosmic
ray particles produced by this solar flare ionized a region well below the
normal Z)-region of the ionosphere, thus producing the large SPA. (Only
10 such solar flare cosmic ray events have been observed in the period from
February 1942 to December 1960.)

In addition, analysis of the 16 kc/s data has revealed variations in phase
coincident with meteor shower activity. The use of the phase-coherent de-
tection technique at VLF is apparently a sensitive indicator of the worldwide
ionizing effects of meteors which are not as easily seen in smaller volume
samples, such as those obtained by VHF forward scatter, radar, and optical
observations.

Magnetic Field Micro pulsations and Electron Bremsstrahlung.
Enhanced magnetic micropulsation activity in the auroral zone near College,
Alaska, has been observed simultaneously with increases in electron brems-
strahlung intensity. Measurements of the magnetic field fluctuations were
made with a 2-m-diam loop antenna of 21,586 turns with its axis in the mag-
netic North-South direction. The system had a flat response to magnetic flux
density in the frequency range of 0.4 to 0.04 c/s. Bremsstrahlung from
bombarding electrons having energies greater than 50 kev were observed with
balloon-borne Geiger counters. X-ray bursts, representing high energy elec-
tron influx, were found to be coincident with the magnetic field micropulsa-
tion amplitudes. Balloon measurements of electron bremsstrahlung using
rapid time response scintillation counters give some indication of the exist-
ence of bunching in the incoming electron density. Further observations
should show whether such fluctuations are also simultaneous with the
magnetic field pulsations.

Ray Tracing Through The Real Ionosphere. Ionospheric data col-
lected during the IGY show that large regions of high electron density exist
in the vicinity of the magnetic dip equator. Under such conditions the as-
sumption of a spherically stratified ionosphere is invalid and it becomes
necessary to plot the radio wave ray paths in detail so as to ascertain the
modes of propagation.

Cross sections, along the 75° west meridian, have been made for noon
and evening conditions in March 1958. Neglecting the earth's magnetic
field, rays have been constructed from a point located at 20° North latitude
for several frequencies and angles of elevation.

125

Mountain-top transmitting location for studies of fading characteristics in
wide-band transmission systems. Receivers are located at a distance of 70
miles on the plains within the line-of -sight. Problems of space telecommuni-
cations have led to a need for more data on long line-of-sight transmission
paths (page 128).

Of particular interest is the presence of supermodes. These involve ray
paths that undergo two successive reflections from regions of high electron
concentration without the usual ground reflection in between. In this way
signals can propagate at frequencies considerably higher than the classical
maximum usable frequency.

Doppler Fading Studies. Over the past year a sensitive technique
has been developed for the recording of the frequency variation of ionospheri-
cally propagated radio waves. These frequency variations are of the order
of a few cycles per second and for purposes of analysis they are recorded
on magnetic tape traveling at a speed of y50 ips. By playing the tape back
at a speed of 30 ips the frequency variations appear as an audio tone which
can be analyzed by conventional techniques.

The 20 Mc/s transmission of WWV has been recorded at Boulder for a
number of months in the winters of 1959-1960 and 1960-1961. Within a
minute of the optical onset of a large solar flare of November 12, I960, the
frequency started to increase. This increase can be interpreted as a down-
ward motion of the reflecting level. Later the ionosphere stopped moving
and the frequency returned to normal. This technique can also be used
to identify magnetic storm effects and traveling disturbances in the F region.
During a severe magnetic storm it has been observed that the F layer loses
its specular reflection character and degenerates into a turbulent medium.

126

First Rocket'Borne Soundings of the Topside of the Ionosphere,

Shortly after 1800 EST on June 24, 1961, a two-frequency ionosonde was
carried to an altitude of over 1000 km off Wallops Island, Va., by means
of a four-stage rocket (Javelin). Successful radio pulse reflections from
the topside of the ionosphere were obtained for about 13 of the 15 minutes
that the payload was above the height of the F region maximum electron
density. The experimental technique involved is essentially the same as
that used by the network of bottomside sounders except that the rocket-borne
sounder was completely transistorized and operated at a lower power.
Unexpected effects were observed as the sounder passed through levels in
the ionosphere where the plasma frequency was equal to the sounding fre-
quency. Also, some evidence for the presence of ionization irregularities
at altitudes of 700-900 km was obtained. A preliminary analysis of the
rocket results suggests a neutral atmosphere scale-height of about 70 km
between the altitudes of 400 and 600 km, implying a temperature of about
1,200 °K (assuming an oxygen atmosphere).

The purpose of the rocket experiment was to test the sounding system
that is to be used in a fixed-frequency satellite topside sounder scheduled
to be placed in orbit in 1962. NBS responsibilities in this program include
overall planning, design and performance of the experiment, and analysis of
the resulting data. Airborne Instruments Laboratory, a division of Cutler-
Hammer Company, is designing and building the rocket and satellite pay-
loads and the ground data handling equipment. Technical management and
sponsorship is provided by the National Aeronautics and Space Administra-
tion (Goddard Space Flight Center) .

Studies of the Interplanetary Medium. A study of the relation of
solar emission of medium-energy particles to other types of solar activity
has revealed new facts about the interplanetary medium. These particles,
first suspected in the large solar event of February 1956, have been detected
in the earth's atmosphere and their effects studied by means of VHF forward-
scatter signals. These data, and others measuring the ionospheric effects
of the solar particles, show that around the time of maximum solar activity
the solar cosmic ray particles take much longer to reach the earth from
the sun than they do near minimum activity. Comparison with character-
istics of solar particles of higher and lower energies show that these medium-
energy particles must move in the interplanetary magnetic field not as single
particles, but as a group. Consideration of directly-observed energy spectra
of the various solar particles show that this group behavior is to be expected
if the interplanetary field is regular but weak near solar minimum activity,
and contains regions where the magnetic field intensity is 10"4 or 10"5 gauss
near the maximum of the solar activity cycle. Linear dimensions, field
strength, and frequency of occurrence of these regions of enhanced magnetic
field, estimated from the behavior of the solar particles, are found
to be consistent with the hypothesis that the clouds are formed through
the action of low-energy solar particles. The effect of these outward-moving
magnetic clouds on the velocity distribution of cosmic rays accounts for the
main features of solar modulation of cosmic rays.

127

Radio Reflections from Artificial Electron Clouds, In a coopera-
tive program with the Air Force Cambridge Research Laboratory, the Bu-
reau has been involved in the operation of strategically located ionosondes
during rocket experiments aimed at the creation of electron clouds. In these
experiments relatively small amounts of various substances (such as sodium)
are injected into the atmosphere at ionospheric heights. In one class of
experiments, clouds of free electrons result through the ionization of the
ejected material by sunlight. By permitting a measurement of the radio dis-
tance to ionized clouds over a wide range of radio frequencies, the ionosonde
is a valuable tool for the study of cloud position, drift, and growth. Studies
of the drifts of these clouds allow determination of wind velocities and the
height gradients. For example, a value of about — 7m/s/km was deduced
for the East-West height gradient of the drift speed at 100 to 120 km during
July-August 1960 over northern Florida.

RADIO PROPAGATION ENGINEERING

More efficient use of the radiofrequency spectrum is the aim of the Bu-
reau's program in radio propagation engineering. This objective requires
a basic understanding of radio wave propagation, noise, and interference.
To this end theoretical and semi-empirical prediction methods are developed
and compared with statistical samples of data on radio wave propagation and
radio noise. During the past few years it has been found desirable to in-
crease emphasis on the direct measurement of the characteristics of the
atmosphere which affect the propagation. Further emphasis is also being
given to studies of propagation and noise at the two extremes of the useful
spectrum: above 5,000 Mc/s and below 30 kc/s. In this way it is hoped
that a better understanding of these portions of the spectrum will lead to
their more extensive and efficient use.

Tropospheric Transmission Loss Predictions. New methods were
published in the past year for predicting the transmission loss expected on a
point-to-point tropospheric radio circuit. These thus provide an accurate
basis for designing such radio systems. The accuracy of these prediction
methods is such that costly path loss measurements prior to the installation of
such a communications system are no longer necessary : These measurements
can often be misleading unless they are made over a sufficiently long period
of time, which in some cases may be several years.

Wideband Data Transmission. Current use of radiofrequencies,
with the transmission of large amounts of information, often involves very
wideband systems. The advent of space telecommunications and high-
altitude space vehicles has made it necessary to consider very long line-of-
sight paths involving transmission through the troposphere. A measure-
ment program has been initiated to investigate the maximum effective band-
width that the troposphere can support without serious distortion due to
multipath effects both within and beyond the line-of-sight. The within-line-
of-sight observations have been made from a mountain site in Colorado

128

towards the plains, using two microwave signals separated by a difference
in frequency corresponding to very wide communication bandwidths. The
beyond line-of-sight measurements are being made between Boulder, Colo.,
and Altus, Okla., using large parabolic antennas ranging in size from 14 to
60 ft in diameter at the receiving and transmitting terminals. The informa-
tion obtained will help to determine the ultimate volume of information that
can be transmitted over long tropospheric paths and assist in the design of
systems employing this type of propagation.

Mutual Interference Between Surface and Satellite Communica-
tion Systems. Artificial earth satellites have opened up new horizons in
long distance communication possibilities. Optimum frequencies for satel-
lite communication purposes lie generally in the 1,000 to 10,000 Mc/s por-
tion of the radiofrequency spectrum. Since this portion of the spectrum is
presently in use by many communication services, satellite communication

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Receiving antennas used in studies of obstacle-gain propagation over Pikes
Peak. Under certain conditions, signals propagated across mountain ridges
are found to be far stronger than if the obstacle were not there (page 130).

129

systems will be expected to share frequencies with these existing services.
Predictions have been made of the conditions under which these frequencies
can be shared by conventional point-to-point microwave relays and satellite
systems. A study sponsored by the Joint Technical Advisory Committee of
the Institute of Radio Engineers predicts that frequency assignments may
be shared if adequate geographical separation of terminals is provided.
Theoretical studies and an experimental program using the NBS 60-foot
parabolic antennas were conducted to determine the minimum separation dis-
tance and the minimum antenna elevation angles for the space communication
system, such that the interfering signal power appearing at the receiver input
terminals was below the interfering level. In order to make reliable estimates
of these interfering conditions, these measurements will necessarily be con-
ducted over an extended period.

Technical Factors Influencing Allocations, The advent of space
telecommunications, together with the increasing use being made of the
crowded radio spectrum, requires the application of technically sound pro-
cedures in radio frequency allocations to assure maximum efficiency of usage
and adequate provision for all radio services. The Central Radio Propaga-
tion Laboratory, in cooperation with the Interdepartment Radio Advisory
Committee and the Federal Communications Commission, has undertaken
a general study of propagation factors important in radio frequency alloca-
tion, giving consideration to all types of radio service presently in use or of
future concern.

Signal Characteristics of Mountain Obstacle Paths. Under cer-
tain conditions signals propagated across mountain ridges are found to be
far stronger than if the mountain were not there. In order to take optimum
advantage of this effect it is necessary to be able to estimate the variation in
transmission loss over these paths and to understand the conditions under
which space diversity may be used to overcome fading. A long-term series of
measurements was completed in eastern Colorado using Pike's Peak as a
knife-edge type obstacle. Sample recordings were made at two frequencies
(100 and 750 Mc/s) over a period of nine months. Empirically derived func-
tions based on line-of-sight fading phenomena specially adapted to this type
of propagation give results which closely approximate the measured fading
characteristics.

Refraction Effects in Microwave Tracking Systems. Modern pre-
cision missile radio guidance systems using microwaves have their ultimate
accuracy limited by the refractive index irregularities in the troposphere.
A program is being conducted to measure the effects of atmospheric in-
homogeneities and turbulence on such systems. Using specially developed
techniques on the unique terrain of the Boulder area, an experimental track-
ing system was constructed to simulate the basic functions of the Mistram
system being built for the Air Force. This system is being used to record the
variations in apparent positions which result from atmospheric variations.
Simultaneous recordings are made of various atmospheric quantities such as

130

Airborne refractometer equipment used in studying the effects of atmospheric
inhomogeneities and turbulence on missile radioguidance systems using micro-
waves (page 130).

Radio propagation paths under study by the Bureau to provide information on
factors affecting the design and use of radio systems. Ionospheric, ground-
wave, and line-of-sight paths are investigated to define the limitations, disturb-
ances, and capacity of the transmission medium as a channel (page 128).

131

refractive index at each of the antennas in the system, and at a number of
height levels on a tower near the terminals of the system. In addition, micro-
wave refractometer measurements are made by an aircraft flying approxi-
mately along the propagation paths. These data are being examined for cor-
relation with the apparent position variations of a fixed target simulating a
missile to investigate the feasibility of using them for correcting the radio
system data. Preliminary work has shown that some of the long-term
(several hours or more) atmospheric effects can be reduced significantly by
proper atmospheric measurements. However, no methods have been found
as yet to make significant or reliable correction for the short-term effects
(hourly or less).

Radio Meteorological Sensors. The results of an investigation con-
cerned with the problem of time-lag constants in the humidity and tempera-
ture sensors of standard radiosonde instruments currently in use by civilian
and military weather organizations shows clearly that corrections for the
time lag in the sensors of both parameters are necessary for correct inter-
pretation of the observed readings. Radiosonde observations have been
universally used for determining the radio refractive index properties of
the atmosphere with altitude; such observations are required not only for
predicting the normal refraction of radio waves around the curved surface
of the spherical earth, but are also used for predicting the strength of signals
resulting from atmospheric turbulence and tropospheric waveguide propaga-
tion commonly known as ducting. It is especially important to take into
account the time lag of these radio meteorological sensors in studying the
climatological occurrence of radio ducts. By ignoring sensor time lag one
tends to underestimate ducting incidence; by correcting only for humidity
sensor lag, ducted incidence is overestimated.

Atmospheric Re fr activity Models. The variation of the refractivity
of the atmosphere with height above the surface of the earth is important
in the prediction of tropospheric radio field strengths. A study of refrac-
tivity with height made by radiosonde observations throughout the world
indicates that a satisfactory model of the atmosphere can be represented by
the sum of two exponential quantities, one dealing with the dry properties
of the atmosphere, and the other dealing with the humidity properties of the
atmosphere. The dry and wet exponential terms are sensitive indicators of
climatic differences, and in the course of the study maps of each were pre-
pared for the United States for both summer and winter. The bi-exponential
model yields more accurate estimates of refractivity structure in the tropo-
sphere than the earlier single exponential model, and consequently gives
more reliable estimates of refraction for initial elevation angles in excess of
3°. Only negligible improvement for the near zero angles of departure
commonly used in tropospheric propagation are obtained.

Automatic Amplitude Distribution Analyzer. An analysis system
for determining the principal statistical parameters of time varying radio
propagation data was completed. These parameters are cumulative ampli-
tude distribution, fade rate versus data level, fade or enhancement duration

132

distribution at specific data levels, and the distribution of percent of time
preset fade or enhancement durations are exceeded. The system is designed
to analyze data recorded on magnetic tape, making it possible to analyze
most field data at a rate 100 times the speed at which it was recorded. The
input data is in the form of variable voltage, representing the fading charac-
teristics of the strength of the measured radio signal. The results are auto-
matically recorded on a digital printer at the end of each analysis period.

Engineering Standards for Tropospheric Communication. A re-
vised and updated 360 page handbook of engineering standards for tropo-
spheric telecommunications was prepared, partly in response to demand in
excess of the 1960 edition and partly at the request of the Air Force for a
shorter version of the material. Methods for calculating system perform-
ance and equipment requirements for line-of-sight, knife-edge diffraction,
smooth and rough earth diffraction, and forward scatter are given with
several new concepts and a general updating over the original handbook.

Prediction of Radio Noise from Thunderstorm Counts. Since at-
mospheric radio noise originates in thunderstorms, an attempt has been made
to predict the radio noise, at any location, from world-wide thunderstorm
counts.

From available records of thunderstorms, the probability of a thunder-
storm occurring during any hour in each of the four seasons has been com-
puted for any geographic location. Using the computed number of thun-
derstorms over the globe for any time, and season and propagation charac-
teristics for the various frequencies and paths, the noise power received
at any location may be calculated for the same time and season, providing
the average power from an average thunderstorm is known. By assuming
a value for this average power, comparisons of measured power and cal-
culated power at each of the seventeen stations in the CRPL radio-noise-
recording network can be made. The average power from a thunderstorm
found from this comparison can then be used to calculate the noise power
at any other location.

To date, due to the volume of computation necessary, only one check
(at 50 kc/s) has been computed for one continental location. In this one
check, the computed diurnal and seasonal variation of noise are in good
agreement with the recorded noise.

RADIO SYSTEMS

The aim of the radio systems program is to provide technical information
relating to propagation factors affecting the design and use of radio systems.
The emphasis of this work is on long-range radio transmission problems —
and methods of measurement — for radio communication, navigation, timing,
detection, and positioning systems. Radio wave propagation studies are
carried out for ionospheric, ground wave and line-of-sight paths to define
the limitations, disturbances, and capacity of the transmission medium as a
channel. The information obtained is directed toward guidance of engi-
neering practices, allocation and use of radio frequencies, and evaluation

133

Array of 25 Yagi antennas used to pinpoint the direction of radio signals re-
ceived from "forward scatter" transmission (page 136).

of system capabilities and limitations. Standards and methods of measure-
ment are developed for radio systems to fulfill the needs of federal agencies
and industry involved in radio telecommunication operation and regulation.
Studies of information theory and coding, modulation, and antenna design
are directed toward improvement of the reliability of systems and to the
efficient utilization of the radio frequency spectrum.

Low and Very Low Frequency Systems (30—300 kc/s). Theo-
retical computations of the propagation of ELF and ULF electromagnetic
waves have been carried out to provide a solution for the propagation of
spherical waves in and about a spherical earth of finite conductivity. A flexi-
ble theoretical computing model for the lower ionosphere was developed
for VLF-LF-MF and HF wave propagation. The model is a multi-slab
electron-ion plasma with superposed magnetic induction of arbitrary direc-
tion. Computations have been made of the effects of various types of dis-
turbances on waves propagated via the lower ionosphere. Graphs, curves,
and charts are being prepared to assist in practical system studies in the
ELF, VLF and LF region.

Analysis of transient propagation of LF radio waves has been conducted
to assist in evaluating the accuracy of pulse navigation systems. Techniques
for transforming from the frequency domain to the time domain for analysis
of linear systems were further developed. A method was devised and tested
for measuring effective ground conductivity and long paths by comparison
of recorded complex spectra of atmospheric (lightning discharge) wave-
forms. The nature and occurrence of atmospherics, as well as modulation
and receiving techniques, are studied to improve methods for elimination
or reduction of noise effects in VLF/LF systems.

High-Frequency Systems. Experimental studies of high-frequency ion-
ospheric radio propagation over Arctic paths were completed for the Air
Force and the Navy. Results were obtained on the attenuation, or transmis-

134

sion loss, of radio signals as a function of frequency over paths subject to
severe ionospheric disturbances. Galactic noise (VHF riometer) absorption
measurements taken at vertical incidences near the path midpoint were com-
pared with the oblique path transmission loss to determine useful relation-
ships between galactic noise absorption and oblique high-frequency radio
signal attenuation. The dependence of transmission loss on the geographical
location of terminals and the angle of signal arrival was investigated for
paths transiting the Arctic. The short term pulse-to-pulse and amplitude
perturbations during ionospheric disturbances were investigated to determine
modulation limitations for HF arctic circuits.

A study was completed showing the effect of the radiation angle upon high-
frequency transmission loss for long-range transmission.

Previous experiments have suggested that certain high-frequency radio
waves may be propagated by ducting along the magnetic field lines of the
earth through the exosphere. The experimental program is being expanded
by higher pulse powers and a continuous wave radar technique for more
detailed study of propagation of backscatter echoes. Frequency shifting
will be used to obtain the wavelength dependence of this propagation mode.
The statistics of the occurrence of this mode of propagation will be examined,
including the change in path transmission loss.

An electronic computer program for computing the path Maximum Usable
Frequency and Optimum Traffic Frequency has been completed for the Navy.
The program utilizes for ionospheric input data the numerical mapping tech-
nique developed by another NBS laboratory. With this program it is only
necessary to know the path coordinates, month, and solar index to determine
the usable frequencies as a function of time of day. The program, which
can be readily changed to accommodate any particular system, is being
extended to cover Lowest Useful Frequency computations.

A study is being conducted for the Navy to determine the applicability
of electronic computers to real time computation of the optimum operating
frequency for any HF circuit. All known factors influencing the performance
of HF radio circuits are being examined to determine their predictability
and usefulness for the computer techniques.

Comprehensive high-frequency propagation studies on behalf of the Ad-
vanced Research Projects Agency are being undertaken to measure phase
and path-length changes, and group path time delays. This program is
directed toward determining the short-term behavior of the natural iono-
sphere in relation to limitations of nuclear detection at long ranges. Both
short and long term variations will be measured to determine sporadic and
cyclic effects. A study was undertaken to determine instrumentation re-
quirements for observations of the fine structure of the ionosphere by the
observation of the amplitude, phase and polarization of both backscattered
and forward propagated signals.

Planning has begun for a new high-power ionospheric radar research facil-
ity for HF and VHF studies, to be located at CRPL near Boulder Laboratories.

135

The U.S. Air Force has made available components of a Ballistic Missile
Early Warning System radar transmitter which will serve as the power supply
and nucleus of the 5-million-watt research radar.

Very High Frequency Systems. A long-term project on the study
of signals scattered from the D region was continued. Signals were recorded
at 30, 40, 50, 74, and 108 Mc/s through September, and at 30 and 50 Mc/s
following completion of the frequency-dependence program at that time. It
was determined that signals at the lower VHF frequencies suffered longer
fade durations. Characteristic depths of fade are dependent upon prevailing
transmission loss and are greater under weak signal conditions. The power
spectrum of the received signal increases with carrier frequency and antenna
beamwidth. Average signal-envelope fading is greatest near midnight and
lowest near noon.

Antenna Research. An electronically scanned antenna capable of
high scan rates was expanded to 25 elements, giving a 1%° beamwidth. Ob-
servations of path direction variation of ionospheric scattered signals were
demonstrated. This technique of antenna steering is expected to be valua-
ble in observing the direction of arrival of radio signals arriving from the
great circle path.

The principles of the electronic scan — demonstrated by the successful opera-
tion of the seven-element array — were further developed. The array was
increased in size to 25 Yagi elements so that the overall width is now approxi-

Part of a single antenna, consisting of 18,000 dipoles and covering 22 acres,
built near Lima, Peru. The antenna will be used to probe the ionosphere,
exosphere, interplanetary medium, and sun by means of radar (page 140).

136

mately 800 feet (33.6 wavelength). The width of the main beam was re-
duced to between 1.5 and 1.7 degrees, giving a rather fine-grain resolution
between the components of signals arriving from different directions.

The equipment was operated successfully in order to collect data and to
develop techniques for recording, interpreting and displaying the data. On
June 16th an observation was recorded of signals arriving simultaneously
from two directions via sporadic-^ reflections. It is believed to have been
the first such observation on record.

Studies and experimental measurements are being conducted to provide
an improved antenna capable of receiving multiple steerable beams for any
direction of transmission or reception. Concentric circular arrays of verti-
cal monopoles using phasing and amplitude tapering are being studied.
Measured results approaching theoretical expectations have been obtained
on an array of one center element, an inner ring of ten elements, and an outer
ring of 20 elements operated at 90 Mc/s. Construction of a 20 Mc/s model
is underway.

A comprehensive study is being conducted on techniques and methods of
measuring complex fields. Waves of arbitrary polarization and with multi-
ple propagation paths and directions of arrival are being considered. The
purpose is to develop a procedure for determining the response of any an-
tenna (of known response pattern) to a complex field. Methods are being
developed and tested for measuring amplitude, direction of arrival, polariza-
tion, and relative time phase of several multipath components of a complex
field. Field-strength meters are being examined for their adequacy for both
cw and pulse measurements.

Modulation Research, The chief obstacles to obtaining reliable sig-
nal transmission through the ionosphere are atmospheric noise, time-variant
transmission loss, and multi-path propagation. One of the principal aims
of the modulation research program is to characterize the time-variant, dis-
persive nature of ionospheric channels and the noise limitations at the re-
ceiver. In order to study the effect of channel distortions on signals it is
also necessary to study the nature of the "communication source function"
or the input modulation to the channel.

During the past year a survey of results obtained in many laboratories
throughout the world on statistics of human speech as a modulating signal
envelope has been made and supplemented by laboratory measurements.
The effects of pre-emphasis of high audiofrequencies and clipping and filter-
ing of speech signals has been studied. In channel characterization, signifi-
cant advancements were made in the observations of pulse-to-pulse phase
stability and pulse-amplitude fading over high-frequency auroral paths.
Using pulses of 1 to 20 milliseconds duration, phase perturbations between
successive pulses were analyzed over the path from Barrow, Alaska, to
Boulder, Colo. Interpretation of the results was aided by concurrent sweep-
frequency ionospheric soundings and oblique incidence measurements over
the same path. It was found that the phase variations on this path mainly
represented rapid movements of ionospheric irregularities rather than inter-
ference effects between separate modes of propagation.

616114 0—61 io 137

A new program has been initiated in information theory and coding for
radio channels. New requirements for great communication capacity and
reliability, with corresponding demands to reduce congestion in the radio
spectrum, suggest a trend toward digital transmission in the design of com-
munication systems. This trend is fostered by developments in digital com-
puters and the theoretical tools of information theory and coding. To ap-
proach the accuracy and efficiency of transmission indicated by Shannon's
Theorem, digital transmission is essential. In this program a preliminary
study and report has been made of the applicability of error-correcting codes
in radio circuits as compared with existing error-detection automatic- repeti-
tion systems such as the ARQ.

Further improvements were made in techniques for noise reduction and
multiple frequency shift digital transmission in the VLF band for defense
applications.

Navigation and Timing Systems. A year ago, feasibility was estab-
lished for time synchronization of clocks separated by up to 1,500 miles,
to an accuracy of one microsecond, using clocks associated with a low-fre-
quency Loran C navigation system. The 100 kc/s ground wave pulse is used.
Time synchronization obtained by this means is approximately 1,000 times
more precise than that obtainable by using high-frequency radio techniques
such as WWV radio signals, and probably 10 to 50 times better than obtain-
able with very-low-frequency transmissions. The study was carried out
for the U.S. Air Force, and the synchronization was demonstrated on the
Atlantic Missile Range for application to launching and tracking problems.
Further studies have been carried out on possible extension of the distance
range by use of sky-wave signals.

The work on the Loran C clock provided background for design and con-
struction of instrumentation for an atomic time accumulator, for use with
the NBS national primary standard of frequency. Times derived from astro-
nomical sources are subject to errors of the order of 1 millisecond for any
given observation. A clock operating from the best available frequency
source is capable of measuring time intervals to better than 1 microsecond
as related to that frequency source. This program will provide a means for
the Bureau to maintain a time scale based on the period of an atomic transi-
tion. Several such times scales are being maintained internationally, and
their comparison is of scientific importance, in view of international con-
sideration of redefining the second in terms of an atomic transition. A
means is also provided for the Bureau to check various time signals against
an atomic source and to publish corrections of these time signals as they
relate to the atomic time source.

The basic concept of this instrumentation is first, a number of pulse
dividers to provide redundancy and allow for checks against each other; sec-
ond, battery standby power to provide for uninterrupted service if primary
power is interrupted; and third, a means for reading out or checking the
dividers one against another. The objective of the entire instrumentation

138

Magnetic probes are used to study the hydromagnetic interaction between a
shockwave and a magnetic field. Radio frequency radiations resulting from
the interaction have been observed. This creation in the laboratory of electro-
magnetic radiation from plasma should lead to a better understanding of elec-
tromagnetic processes which occur in the upper atmosphere (page 140).

is to provide one second and one minute pulses derived from the 1 Mc/s stand-
ard frequency on a fail-safe basis. Instrumentation was essentially com-
pleted during the past year and component units will be integrated into the
clock system early in the next year.

UPPER ATMOSPHERE AND SPACE PHYSICS

The research program in upper atmosphere and space physics recognizes
the urgent need to increase the knowledge and understanding of the physical
properties and processes in the media surrounding the earth and in inter-
planetary space. Such knowledge and understanding is essential to the ex-
panding application of radio communication in the space age.

139

Preliminary Measurements of Electron Densities to 1,200 Kil-
ometers, A new ionospheric research facility, based on the incoherent
scatter of radio waves from free electrons, will provide the Bureau with a
powerful and very sensitive research tool for important ground-based observa-
tions of the ionosphere, exosphere, interplanetary medium, and the sun.
This major constructional effort is now underway at the new Jicamarca Radio
Observatory near Lima, Peru, and important new advances are anticipated
as soon as the 6 megawatt peak-power radar system is fully operational,
probably during late FY 1962. Already one-half of the huge 18,000-dipole
broadside antenna has been completed. Preliminary observations using
part of the antenna system, and a relatively low-power transmitter, have
given several electron density profiles to heights of 1,200 kilometers. These
preliminary observations indicate that the decay of electron density with
height above the maximum of the F region is usually exponential for several
hundred kilometers. On several occasions a rather abrupt discontinuity has
been observed in this exponential decay, in that, at great heights, the ioniza-
tion is found to decay much more slowly than in the first several hundred
kilometers above the peak of the F layer.

Radiation Produced from a Plasma. Plasmas produced by a high-
velocity shockwave traveling at speeds in excess of Mach 100 in helium
have been studied in the laboratory in the presence of a transverse magnetic
field. Radiofrequeney radiations resulting from the hydromagnetic inter-
action between the shockwave and the magnetic field have been observed.
This creation in the laboratory of electromagnetic radiation from plasmas
is a major step towards duplicating under controlled conditions electro-
magnetic processes which occur in the upper atmosphere. An additional
important advance has been the development of a high-speed camera, capable
of operating at a rate in excess of one hundred million frames per second
and designed to study the luminous phenomena in the shockwaves.

Investigations in Particle Processes. Normal HF communications
are notoriously unreliable at high latitudes due to disturbances resulting from
bombardment of the upper atmosphere by energetic particles guided to these
regions by the geomagnetic field. A major advance was made in studying
this field when a 10 Mc/s riometer system was designed and constructed to
measure cosmic noise absorption. This system records continuously the
cosmic noise strength on both circular polarizations, and offers the advan-
tages over earlier systems of a tenfold improvement in sensitivity, together
with a greater dynamic range and an indication of the height at which the
absorption occurs.

Cosmic Noise Study at USSR Mirny Base, Antarctica. In coopera-
tion with USSR scientists, an important quantitative study of cosmic noise
absorption as observed in the high southern latitudes was undertaken. This
work will not only produce important data for the southern hemisphere, but
it will also permit the determination of the relationships between absorption
events occurring simultaneously in the two polar regions.

140

Satellite Radio Signals Used to Study Structure of Ionosphere,

Communication with vehicles in space poses difficulties since signals from
space as received on earth are perturbed by irregularities in the electron
density of the ionosphere. By studying radio signals received from satel-
lites it has been possible to measure the ionospheric electron content and
irregularities above the region of maximum electron density. Previous
studies of signals from radio stars and satellites provided evidence of ion-
ospheric irregularities which are 100 to 500 km in horizontal extent, and
which occur during daylight hours on about one-third of all days. The cur-
rent studies include investigations of the size, shape and motion of these ir-
regularities as observed at separate multiple observing stations.

Meteor Burst Propagation Observations Successful, A full scale
field observational program was conducted to provide statistical informa-
tion on the radio energy scattered by transient meteor ionization. This
information is of great importance in studying the feasibility of meteor-burst
communication between widely separated points, and in designing appro-
priate communication equipment. Measurements of propagation charac-
teristics of transmissions at 30, 50, and 74 Mc/s were conducted over three
paths of similar length. Two paths, crossing at right angles at the midpoint,
were used in the U.S. to determine the dependence of meteor echoes on path
orientation. The third path, in Alaska, was used to identify and measure
meteor propagation characteristics peculiar to the auroral region. With
successful completion of the field observations, the digitized data are now
being analyzed to determine the pertinent propagation parameters.

Observatory Installed at Maui, Hawaii, The Bureau and the High
Altitude Observatory of the University of Colorado have cooperated for
some time in a study of the zodiacal light. Recently the collaboration has
been extended to include the Hawaii Institute of Geophysics. An observa-
tory has been established with National Aeronautical and Space Administra-
tion support on Mount Haleakala, Maui, Hawaii. The program includes,
in addition to studies of the zodiacal light, systematic observations of the
airglow.

Of particular interest is a strong correlation between the intensity of the
atomic oxygen radiation (6300 A) and certain ionospheric parameters ob-
served by the NBS ionosonde on the island of Maui. It has been found
that the red (6300 A) line airglow intensities can be quite accurately pre-
dicted by a formula involving the parameters foF2 and h'F on the iono-
grams. The nature of the correlation supports the hypothesis that the red line
is due to excitation of atomic oxygen by a photochemical reaction involving
either O2 and electrons or NO+ and electrons.

The photometric observations cover the entire sky and extend over a re-
gion of radius some 1,000 kilometers, in contrast with the ionosonde vertical
soundings which are essentially overhead. The two techniques thus serve
to complement each other and extend the scope of the investigation of the
ionosphere.

141

A mobile satellite observing station, in conjunction with permanent facilities at
Table Mesa, is being used to study ionospheric irregularities and their effect on
the reception of satellite signals (page 141).

In mid-latitudes the relationship between the 6300-A emission and the
ionosphere is less clear and it seems that the photochemical reaction is only
one of several effective mechanisms. The results in the tropics may thus
serve to give information clarifying ionospheric processes which occur in
mid-latitudes.

Numerical Representation of the Ionosphere. Further work un-
der this program has provided the first automatic computer methods for
predicting long-term changes in useful frequencies for ionosphere radio
communication systems. The methods used incorporate recent advances
in applied mathematics and statistics in such a way as to respect as far as
possible the empirical knowledge accumulated in ionespheric studies. The
method developed provides important flexibility in solving problems of
ionospheric radio propagation by treating separately the three basic areas
involved: ionosphere mapping, correlation of ionosphere characteristics with
various indices of solar activity, and application of the theory of radio wave
propagation.

IGY WORLD DATA CENTER A

The Data Center continues to receive IGC and post-IGC data at a high
rate. A special effort is underway to acquire and catalog all outstanding
IGY data. During the year there was a notable increase in requests for data,
most of the requests coming from scientific industry. Plans have been made
to collect and exchange reprints and reports concerning Airglow and Iono-
sphere. This new service will aid scientists in the use of the materials avail-
able from the Data Center.

142

2.3.5. CRYOGENIC ENGINEERING

The Bureau's activities in cryogenic engineering, a rapidly growing spe-
cialized field, center at the Boulder Laboratories. The Bureau provides in-
formation needed for practical applications of materials, systems, and tech-
niques at very low temperatures, and assists Government and industry with
problems arising in this field.

Demand for assistance in projects involving cryogenics has increased
greatly as a result of missile and space programs which rely on cryogenic
liquids as propellants. The growth of cryogenic engineering has been ac-
companied by emphasis on purely scientific programs in which the use of
extremely low temperatures can be an important aid. To cooperate in these
activities, the laboratory conducts research on the physical properties of
materials and properties of fluids, as well as on cryogenic processes and
equipment. In addition, it maintains a national Cryogenic Data Center
where information on cryogenic engineering is collected and organized for
use by other Government agencies, industry, and the public.

Superconducting Electromagnets, High magnetic fields have im-
portant uses as deflectors of charged particles, as, for example, in the particle
accelerators and detection devices of nuclear physics, in magnetohydrody-
namic power converters, and for plasma containment in nuclear fusion re-
actors. Substantial reduction of the power dissipated as heat in electromagnets
can be achieved if the magnet conductor is cooled to low temperatures so as to
greatly reduce its electrical resistance. Until recently, the further step of
utilizing a superconductor was not regarded as practical, because most super-
conductors are driven into the normal state by rather small magnetic fields.
However, in the past year several alloys and compounds have been found to
remain superconducting in the presence of high fields and while carrying
large currents. One of these, niobium-clad Nb3Sn, has been investigated
by NBS, under Atomic Energy Commission sponsorship, in fields up to 190,-
000 gauss. The results indicate that solenoids can be made of this material
that will produce fields of well over 100,000 gauss if operated at 1 to 4 °K.
There is now intense activity in a number of laboratories on high-field super-
conductors.

Properties of para-Hydrogen. The specific impulse of a rocket pro-
pellant varies inversely with the square root of the masses of the ejected
particles. Consequently the most advanced chemical and nuclear rocket
schemes utilize hydrogen as a reactant and as a propellant fluid, respectively.
Data concerning the thermodynamic and transport properties of hydrogen
must now be known with higher accuracy and over wider ranges of tempera-
ture and pressure than have been hitherto necessary. With the support of the
Air Force and, more recently, the National Aeronautics and Space Admin-
istration, the Bureau has completed precise measurements of the pressure-
volume-temperature characteristics of liquid and gaseous para-hydrogen from
20 to 100 °K and at pressures up to 350 atmospheres. Measurements of
the specific heat are in progress. Detailed thermodynamic charts and tables
will be prepared from these data.

143

Cryogenic Materials Data Handbook, The performance of a liquid-
propellant rocket depends critically on the reliability of valves and other con-
trol components. In turn, the design of such devices depends on the avail-
ability of accurate data on the physical properties of the materials used.
The Bureau, under Air Force sponsorship, is compiling mechanical properties
data, thermal expansions, and certain other physical properties data on about
fifty metals, alloys, and plastics that are used in low-temperature equipment,
and is making laboratory determinations where the data are lacking or are
insufficiently accurate. A Handbook containing over 500 data sheets on
these materials used in cryogenics is available from the Office of Technical
Services, U.S. Department of Commerce.

Practical Thermometry. The thermoelectric characteristics of copper
versus constantan, iron versus constantan, Chromel versus Alumel, gold-
cobalt versus copper, gold-palladium versus platinum-iridium, and "normal"
silver versus copper have been determined down to 4 °K. This completes
the present program on the low-temperature characteristics of commonly
used thermocouple materials.

Some of the first germanium resistance thermometers to become available
commercially were calibrated at liquid hydrogen temperatures and were tested
for stability under thermal cycling. Because of their small size, ruggedness,
high resistance, and reproducibility, these thermometers should fill an im-
portant need for a practical thermometer for the region 1 to 40 °K.

A simple, empirical, interpolation method for platinum resistance ther-
mometers was found which can provide the basis for a scheme of calibration

The amount of power needed to produce high intensity magnetic fields can be
greatly reduced by cooling the magnet assembly with cryogenic liquids. Above
is a liquid hydrogen cooled solenoid which was constructed using a stack of
"flat doughnuts" made of turns of aluminum foil separated by paper (see sec-
tion, left). The hole in the center of the solenoid is three inches in diameter;
radial ducts in the "doughnuts" conduct the liquid hydrogen through the
solenoid (page 146).

144

at low temperatures. By calibrating at the ice point, and the boiling points
of hydrogen and oxygen, use of this method provides interpolation accurate
within a few millidegrees down to 20 °K for precision capsule thermometers.
(For other low-temperature thermometry, see page 56.)

Two-Phase Fluid Phenomena. Because the fluids in cryogenic sys-
tems are usually close to saturation, the simultaneous existence of both liquid
and vapor phases (two-phase fluids) is common. A fundamental under-
standing of the behavior of these systems therefore requires basic knowledge
of two-phase fluid phenomena.

Critical flows of two-phase fluids are being investigated theoretically and ex-
perimentally. An ability to predict these flows is necessary for the design
of such cryogenic systems as those handling rocket propellants. Experi-
mental work performed during the past year indicates that even when usual
calculation procedures predict the contrary, limitations imposed upon two-
phase flow systems by the existence of critical flows will occur.

Basic investigations concerned with cavitation are also being undertaken.
The emphasis in the present study is on metastability and nucleation charac-
teristics of systems. Preliminary experimental results show, for example,
that liquid nitrogen can be maintained in a greatly superheated condition
for long time periods.

A study of the behavior of cryogenic systems during the transient period
when the system is being cooled to operating conditions is underway. A
very complete mathematical model is being solved numerically with the aid
of a high-speed computer while dynamic instrumentation is being used to
measure the pertinent variables (e.g., static pressures, momentum, flow rate,
fluid and wall temperatures, geometry) in an experimental program.

The bulk density and density distribution of boiling fluids, and the bubble
dynamics therein, are being studied. The present emphasis of this work
is toward liquid oxygen, for application to space vehicles. The problem of
cooling cryogenic liquids by passing non-condensible gases through them
is also being studied.

Heat Transfer, As heat transfer must be controlled and/or predicted
in most cryogenic systems, there are a number of problems in this area which
must be investigated. The current emphasis is on heat transfer from the
atmosphere to surfaces at low temperature (from 20 to 90 °K). An experi-
mental apparatus has been built for these studies. The surfaces can be held
at 20 °K, 77 °K, or 90 °K; the air velocity can be varied up to 60 knots;
the air temperature controlled between 0 and 100 °F; and the relative
humidity controlled between 0 and 100 percent. The condensation of the
components of air on the surfaces can be studied in detail. The formation
of water frost on surfaces is being analyzed theoretically with the assistance
of a high speed computer.

The behavior of liquid hydrogen under pressurization (up to 600 psia)
and rapid outflow conditions is being investigated so that gas requirements
and fluid conditions during pressurized transfers can be predicted. In con-
nection with the cooldown studies, mentioned previously, as well as with

145

the condensation work, information on heat transfer between solid surfaces
and cryogenic fluids is being obtained.

Cryogenic Equipment and Instrumentation. The growing use of
cryogenic fluids in general, and liquid hydrogen in particular, has neces-
sitated the development of some standard equipment and research into
measurement problems. A standard coupling for use with vacuum-insulated
hydrogen equipment is being developed in cooperation with the Air Force,
the National Aeronautics and Space Administration, and the Atomic Energy
Commission. Programs for the evaluation of pressure transducers at low
temperatures, the determination of dynamic characteristics of temperature
sensors, the measurement of liquid level, and the measurement of mass and
volume flow rates are underway. A device for measuring the density of
flowing fluids has been designed and is being perfected. A survey of the
state of the art of cryogenic instrumentation has been completed.

The most promising method for achieving very low pressures (those found
in outer space) and high pumping speeds at these pressures is cryopumping.
Cryopumps are being investigated to obtain information that will permit
such systems to be designed. The experimental apparatus has been built
and a reliable method for measuring pumping speeds has been developed.

Magnet Research. Problems associated with the production of high-
intensity magnetic fields by means of low-temperature solenoids are being
investigated. The results of these investigations will be used for thermo-
nuclear power reactors, particle accelerators, and other applications where
large volume high fields are required. A high-purity aluminum foil magnet
has been designed and is nearing completion. It is designed to produce a
steady-state field of 100,000 gauss in a cylindrical volume 3 in. in diameter
by 8 in. long. The power requirement is anticipated to be only 4 kilowatts ;
the current will be only 135 amperes; and there will be forced-convection
cooling with liquid hydrogen.

Low Temperature Seals. Last year the discovery of a method of
using ordinary elastomeric O-rings to make excellent static seals at cryogenic
temperatures was reported by the Bureau. These seals are now finding use
in many types of cryogenic engineering applications. During the past year,
methods have been found for making successful seals between flat flanges
with O-rings, replacing the more cumbersome tongue and groove flange
required previously.

Several pertinent physical properties, such as the thermal expansion of
compressed elastomeric specimens as a function of temperature, are being
measured. It is hoped that these measurements will provide data which
will aid in predicting seal effectiveness.

Refrigeration Processes. During the past year, an experimental pro-
gram was completed which made it possible to construct design charts to
aid the analytical design of stable, externally-pressurized gas bearings. A
miniature helium expansion turbine supported on gas bearings, designed in
accordance with a method proposed by the Bureau, has been developed and

146

Disassembled view of apparatus for studying heat-transfer coefficients in liquid
hydrogen systems. Studies are made of the heat-transfer processes occurring
at the surface of the tube in the foreground under various conditions of tem-
perature and heat flux. Heat transfer must be controlled and /or predicted in
most cryogenic systems (page 145).

evaluated. The bearings have proven to be stable over a wide range of inlet
pressure conditions.

Further computational work is being done on refrigeration methods suit-
able for use in the 2 to 30 °K region. Emphasis is being placed on process
simplicity and reliability.

Consultation and Advisory Services* The Bureau is providing con-
sultation on cryogenic engineering problems to the National Aeronautics and
Space Administration in support of Projects Centaur and Rover. Both of
these projects involve the use of liquid hydrogen propellants, and the Bu-
reau's past experience in handling liquid hydrogen under a variety of con-
ditions is being utilized. Support has been given to the principal contractors
on these two programs in the areas of ground support equipment, insulation,
low temperature seals, rolling element bearings, and low temperature window
design. Attempts are being made to standardize hydrogen properties data
and other pertinent properties of materials to aid in uniformity of analyses.

Cryogenic Engineering Data. The documentation unit of the Cryo-
genic Data Center is adding from 50 to 100 new literature references a week
to the storage and retrieval system. Expansion of this acquisition effort is
planned, as this number appears to be less than half of the articles of cryo-
genic interest currently being published. Recoding of a substantial portion
of the reference listings has already been accomplished for conversion to
mechanized storage and retrieval using the NBS Boulder computer facility.
Upon completion of the recoding, an automated bibliography service will be
provided to the cryogenic industry. There has been an increasing number
of requests from the laboratory staff for literature procurement and from out-
side the laboratory for reports and data.

147

The selection and evaluation of thermodynamic data has continued at a
somewhat accelerated rate. With the use of the large, high-speed computer,
data from a great number of sources can be considered and a more accurate
determination of "most probable values" can be made. In a three year
period under sponsorship of Wright Air Development Division, two com-
pendia of "Properties of Materials at Low Temperatures" (Phase I and
Phase II) have been completed. Early in 1961 sponsorship was transferred
to National Aeronautics and Space Administration and the work will be con-
tinued to cover additional properties of the same and other materials for
which data are needed.

Gas Liquefaction, The increased availability of liquefied gases from
commercial and other government sources permitted an appreciable reduc-
tion in gas liquefaction activities at the Boulder Laboratories. About 20,000
liters of liquid hydrogen were procured from other sources, making it nec-
essary to liquefy only an additional 20,000 liters to take care of NBS lab-
oratory needs. Similarly, some 360,000 liters of liquid nitrogen were pur-
chased and only 190,000 liters produced with NBS facilities. As liquid
helium is not yet generally available from commercial sources, the production
of liquid helium remained about the same as for previous years, amounting
to about 3,000 liters. The liquefaction facilities are being maintained in
fully operable condition for production of liqefied gases whenever needed
and on moderately short notice. The facilities are also being used for other
programs of research and developments and for purification studies.

2.3.6. BUILDING RESEARCH

Advances and new developments in science and technology often can as-
sist in solving problems related to building materials, structures, equipment
and facilities. A major objective of the Bureau's building research program
is therefore the development of new knowledge through research in chemis-
try, physics, and engineering. Another important objective is development
of measurement and testing methods needed before some of the modern
knowledge can be applied to the building industry. To facilitate the use of
new knowledge, the Bureau provides aid to other laboratories by devising tech-
niques for accurate measurements, by developing and supplying calibrated
laboratory reference standards, and by participating in interlaboratory pro-
grams for checking the precision of measurements. The Bureau also pro-
vides advisory and consultative services on building problems to government
agencies and others. It cooperates with public and private organizations
in the formulation of specifications and national standards affecting the
building industry.

During the year, various investigations looking to improved cement and
concrete were carried forward. Creep and shrinkage of structural light-
weight concretes were studied because of increasing interest in these mate-
rials. Meanwhile an apparatus was being developed to use electronic
counters and a digital recorder to measure air voids in concrete, thus paving
the way to increased durability.

148

Above: Measuring the deflection of a notched concrete prism during a study
of the mechanism of crack propagation in reinforced concrete structures. Be-
low : Determining the size and distribution of air voids in a polished, hardened
concrete specimen. Air voids have a definite effect on the durability of con-
crete (page 150).

In other projects the mechanisms by which fires are extinguished were
studied, as was the effectiveness of various fire retardants. Improved
measuring techniques were sought for heat pumps and air conditioning
units, and performance of air-to-air heat pumps was evaluated. With a
view to protecting the perishable cargoes in refrigerated trailers, chilled air
distribution inside these vehicles was investigated.

Several problems related to the moisture menace in construction were
studied. An apparatus was constructed, and a method devised, for measur-
ing water vapor permeance through building materials. The moisture
problem in underground pipe insulation was studied, and test methods for
moisture barrier materials for use in underground heat distribution systems
were worked out. To combat moisture in flat insulated roofs as a threat

149

to economy and efficiency of air-conditioning and heating, roof specimens
were studied and information obtained with which to prepare specifications
for self-drying roofs.

Air Void Systems in Hardened Concrete. The quantity and dis-
tribution of entrained air in concrete is related to the production of durable
concrete, and especially to the concrete's resistance to freezing and thawing
and salt scaling. In this connection, knowledge of the amount and size
distribution of air voids in the hardened concrete is essential for study of
the mechanisms by which damage occurs and of the means to produce the
more lasting concretes. To secure the needed knowledge, a linear-traverse
apparatus is being developed, to enable polished specimens to be traversed
under a microscope to determine the distribution of bubble sizes. Electronic
counters and a digital recorder are used in the apparatus. When it is ready,
work will commence on an automatic method for obtaining the bubble-size
measurements, and this will mean saving in time and in operator fatigue.

Creep and Shrinkage of Structural Lightweight Concretes. In
recent years expanded shale aggregates have been used extensively in rein-
forced concrete structures. In order to formulate satisfactory standards and
design practices for lightweight aggregate concretes, in structures subjected
to high sustained stresses, the Bureau conducted experiments on the creep
and shrinkage in expanded shale concretes. This work is supported by the
Expanded Shale Clay and Slate Institute. The creep properties are being
determined for concretes of different strengths and different stress level-
strength ratios. For purposes of comparison, parallel tests are being made
on specimens of normal weight concretes.

Characterization of Cement Compounds by Infrared Spectros-
copy. Infrared absorption spectra were obtained for a number of com-
pounds which occur in portland cement, or are related to compounds formed
in the hydration of portland cement. The patterns, in many cases, were
found sufficiently distinctive to identify single phases. In addition, infrared
was used to distinguish between water of crystallization and hydroxyl groups
and to detect hydrogen bonding. Most of the stable combined water in the
calcium silicate hydrates was found to be in the form of hydroxyl groups,
and all of the calcium silicate hydrates showed some degree of hydrogen
bonding.

Crack Propagation and the Fracture of Concrete. Knowledge of
the mechanism of propagation of cracks in concrete is necessary for better
understanding of the behavior of reinforced concrete structures. Experi-
ments on the properties of concrete beams with crack-simulating notches
indicated that the concept of a critical strain energy release rate being a
condition for rapid crack propagation and consequent fracture was appli-
cable to concrete. Estimates of critical strain energy release rates based on
the locally elevated stress fields in the vicinity of a crack yielded values for
beams with different notch depths which were in close agreement.

150

Calcium Aluminate Complex Salts, The complex compounds of
calcium salts with tricalcium aluminate, important in the hydration, harden-
ing, and durability of cements, were further investigated. A thermo-
chemical study of calcium aluminate monocarbonate was completed, and one
on the corresponding monosulfate and tricarbonate compounds is under way.

Extinguishment of Fires. Investigations were continued and ex-
panded in regard to the mechanism by which extinguishing agents suppress
combustion reactions. Experiments on extinguishment of diffusion flames
by halogenated inhibitors gave results which appear to be more readily
explained in terms of reactions, or other properties of the intact inhibitor
molecules, than in terms of reactions of the halogen fragments obtained from
the pyrolytic degradation of the inhibitor. A search of the literature re-
vealed an unexpected correlation between the efficiency of an extinguishing
agent and the yield of negative halogen ions produced in the dissociative
resonance capture of low-energy electrons by inhibitor molecules. The
subject is receiving further study.

Flammahility of Materials, The radiant panel test for flammability,
developed by NBS and recently adopted as an ASTM tentative method, was
the subject of cooperative studies to determine its usefulness for evaluating
performance of fire retardant and other paint systems. Data obtained
indicate the method provides a sensitive way of measuring the relative
effectiveness of paints in reducing surface flammability of the base material.
Results show that when the paint is applied to a hardboard base, rather than
to the commonly used fiberboard base, the test provides a superior method
of measuring the paint's fire-retardant effectiveness. The study further
indicates that commonly available alkyd or latex base paints, when applied
at coverage rates in the range of 250 to 125 ft2/gal, are effective fire
retardants.

Heat Pump Studies, Experiments were conducted to improve meas-
uring techniques for heat pumps and air-conditioning units, in which ac-
curate determinations of average wet- and dry-bulb temperatures of a stream
of moving air are required. An apparatus was built to study the principles
and techniques for mixing a nonhomogeneous air stream for precise tem-
perature measurement. This apparatus includes a means for providing a
known degree of nonhomogeneity before the air stream enters the mixing
device as well as precise measurements of the wet- and dry-bulb temperatures
after the air stream leaves the mixing device. Performance data on orifices,
baffles, screens, and rotating blades are being correlated with fluid mechanics
theory to develop mixing devices that will provide more precise determina-
tions of the "state condition" of an air stream. The suitability of thermom-
eters, thermistors, and thermocouples for measuring dry-bulb temperatures
in an air stream for a range of velocities from 300 to 2,000 ft/min was
investigated.

Field Studies of Air-to-Air Heat Pumps, Field studies of air-to-air
heat pumps were sponsored by the Office of the Chief of Engineers, the

151

Bureau of Yards and Docks, and the U.S. Air Force. The studies were
carried out under summer and winter conditions in three housing projects
of the Air Force. The purpose was to obtain data on performance factor,
as well as on use of supplementary resistance heat, the contribution made
to heating and cooling loads by the miscellaneous uses of energy in the
houses, and the relation between computed and measured heating and cool-
ing loads. Similar data on energy use in three other Air Force housing
projects employing gas heating equipment and electric air-conditioning
units were obtained for comparison.

Fundamental studies of the nature of combustion and the mechanisms of fire
extinguishment are part of a broad fire research program. Here the effective-
ness of a fire inhibitor is investigated (page 151).

152

Water Vapor Permeance of Building Materials. The building in-
dustry long has recognized that control of moisture and its migration in
and through building materials is a major problem. However, present
techniques for measurement of the permeance of water as vapor do not give
results of sufficient precision. Therefore, there is a critical need for refer-
ence standards in this area and for test methods for making measurements
consistent with established standards. With a view to this need an apparatus
was constructed, and a method, based on an indirect gravimetric procedure,
was devised to measure water vapor permeance. The method eliminates
many errors and variables inherent in most procedures. The same basic
equipment also can be adapted for study of radioactive tracer techniques,
reducing the time for a single determination from days to minutes.

Two materials in film form were selected for possible reference samples.
They were polyethylene terephtholate for low permeance, and polycarbonate
film for higher permeance. Ultimately, it is expected the method and the
reference samples can be used for the calibration of techniques and equipment
in other laboratories.

Underground Heat Distribution Systems. Investigations of under-
ground pipe insulation systems were essentially completed under the spon-
sorship of the Office of the Chief of Engineers, the Bureau of Yards and
Docks, and the U.S. Air Force. The investigations revealed the necessity
for long-term integrity of the moisture barriers used to protect the insula-
tion. Moreover, the provision of air passages around or through the in-
sulation to permit moisture removal by ventilation was demonstrated to be
useful as an aid to protection and preservation of insulating materials.

An air-pressure test was recommended, to establish initially the absence
of leaks in the moisture barrier of field installations, where free water is
likely to be in contact with the heat-distribution system. Desirable physical
characteristics and test methods for moisture barrier materials for use in
underground heat distribution systems were worked out. A report on the
investigation is being prepared for publication.

Moisture in Flat Insulated Roof Constructions. The actual insu-
lating effect of insulated flat-roof constructions may depart greatly from the
design values, due to moisture in the insulation. The moisture may be in
the insulation when it is installed, or it may get into it later. As a result,
the air-conditioning or heating of a building may be impaired, and the
operating cost for these services may become excessive.

In an investigation sponsored jointly by the Office of the Chief of Engi-
neers, Bureau of Yards and Docks, and U.S. Air Force over the past 5 years,
tests of about 60 roof specimens under conditions simulating natural winter
and summer roof exposures with daily solar heating were conducted. The
results demonstrated that many common insulated flat-roof constructions
are markedly reduced in insulating value by moderate amounts of moisture,
and that under service conditions, substantial drying of wet constructions
often is impracticably slow. However, some constructions were found to

616114 o— 61 11 153

have good self-drying characteristics. The properties conducive to self-
drying appear to be thermal conductivity, vapor permeability, moisture
absorptive capacity, and possibly the hygroscopicity or capillarity of the
component layers of roof construction, as well as their thickness and arrange-
ment. Although investigations are continuing, sufficient information was
obtained to prepare a specification for self-drying roof constructions.

Standards for Refrigerated Vehicles, A study of chilled air distri-
bution inside refrigerated vehicles loaded with a closely-packed perishable
cargo was supported in part by the U.S. Department of Agriculture. The
study showed that the chilled air must circulate around the cargo and absorb
the heat transmitted through the surrounding walls to protect the cargo
adequately. Provision of sufficient air space for chilled-air circulation under
the load was found to be the factor of greatest importance in improving the
temperature distribution. The results further showed that the flow resist-
ance of each parallel path for air flow must permit an air flow approximately
proportional to the heat transmission into the corresponding part of the
air circuit. It developed also that under favorable conditions there was
little heat exchange between the chilled air and the cargo. The maximum
temperature variation in the cargo was about equal to the temperature differ-
ence between the supply air from and return air to the cooling unit. This
investigation is still in progress.

A related program, supported by the U.S. Department of Agriculture and
the Truck Body and Equipment Association, was initiated to develop a test-
ing and rating method for refrigerated trucks that would take into account
the solar load and the heat transfer caused by intermittent opening of the
doors in stationary vehicles.

Design Loads for Plumbing Systems. Analyses of experimental data
on the hydraulics and pneumatics of plumbing drainage systems produced
criteria aimed at providing pipes adequate to carry maximum expected
loads, without being unnecessarily large and costly. The results indicate
that substantial reductions in pipe sizes may be achieved safely in some
cases. This research is related to main vertical drains and vents, and to
horizontal drain systems.

Advances in Thermal Conductivity Measurements. Many engi-
neering undertakings involve measuring or increasing or limiting the flow
of heat. For this reason, industry, research laboratories, and defense
agencies need reliable data on thermal conductivity of materials ranging
from insulators to highly conducting metals, at temperatures from the
cryogenic range to 1,000 °C and higher. To meet these needs, the Bureau
developed new and improved steady-state methods for measurement of con-
ductivity, covering extended temperature ranges for a variety of materials.
Thermal conductivity of these materials ranges from 0.00025 to 5 w/cm °C.

The different methods made possible thermal conductivity reference
standards for other laboratories. Through such references, concordance of
results can be confirmed or improved, and simpler apparatus used where
reference standards for its calibration are available.

154

Organic Coatings Manual, With the advent of new synthetic resin
binders and other components of coatings, a need for a modern organic
coatings manual has arisen. Preparation of such a publication was under-
taken, and it is now nearing completion. It will include discussions of speci-
fication products and information on late developments not yet covered by
specifications.

Safety Codes. NBS actively participated in formulation of an Elec-
trical Standard for Machine Tools, sponsored by the National Fire Protec-
tion Association. It was adopted as a tentative standard. Through mem-
bership on committees, NBS also cooperated in revision of codes developed
under procedure of the American Standards Association. These included
the National Electrical Code, sponsored by the National Fire Protection As-
sociation; the Safety Code for Building Construction, sponsored jointly by
the American Institute of Architects, and the National Safety Council; and
the Code for Protection Against Lightning, sponsored jointly by the Na-
tional Fire Protection Association, The American Institute of Electrical
Engineers and NBS.

Symposium on Chemistry of Cement. The Fourth International
Symposium on the Chemistry of Cement was held at NBS from October 3d
to 7th, 1960. It was sponsored jointly by the Bureau and the Portland
Cement Association.

This apparatus, used with an indirect gravimetric procedure, was developed to
measure water-vapor permeance of building materials (page 152).

155

Attendance at the symposia has increased from the 11 at the first (in Lon-
don in 1918) to the 267 from 28 countries at the last. Meanwhile the pro-
ceedings have grown from 69 pages covering 10 papers and 5 discussions
to 68 papers and 88 discussions requiring over 1,500 pages to be published
by the Bureau in two volumes.

In attendance at the Washington meeting were outstanding research
workers and leaders from this hemisphere and abroad. The meeting, in
the manner of its predecessors, brought up to date the present state of
knowledge of the chemistry of cement clinker, as well as the hydration of
cement compounds and cements, the properties of cement pastes and con-
crete, the destructive processes in concrete, and the properties of special
cements. It furnished an opportunity to take stock of progress made, and to
assess needs for and direction of continuing research.

2.3.7. WEIGHTS AND MEASURES

One of the statutory responsibilities of the National Bureau of Standards
is "cooperation' with the States in securing uniformity in weights and meas-
ures laws and and methods of inspection." The responsibility of regulatory
control over commercial weighing and measuring devices and commercial
transactions involving quantity has been left by the Congress to the indi-
vidual States. The Bureau contributes by offering consultative and ad-
visory services to the States and calibration and physical adjustment of
State reference weights and measures standards.

This program has been implemented through the Bureau's Office of
Weights and Measures. The range of services is quite broad, including the
development of ( 1 ) model weights and measures statutes, rules, and regula-
tions, (2) properly designed and accurate physical standards of length, mass,
and capacity, (3) effective procedures for testing commercial weighing and
measuring devices, (4) specially designed testing equipment, (5) plans for
systematic and effective quantity checking of prepackaged merchandise, (6)
administrative procedures, (7) specifications and tolerances for commercial
devices, (8) training schools for weights and measures officers, (9) visual
aids, and (10) publications.

With the assistance of the Office of Weights and Measures, important
amendments were made to existing weights and measures statutes in several
States and completely new statutes were enacted in Alaska and Tennessee.
Appropriate modernizing amendments were made in the Model State Law
on Weights and Measures, the Model Package Regulation, and the Specifica-
tions, Tolerances, and Regulations for Commercial Weighing and Measuring
Devices.

The national weights and measures training laboratory facility was com-
pleted and the first course for supervisory personnel of the States was suc-
cessfully conducted. The requests for Bureau assistance in the conduct of
technical training schools at the State level have greatly increased.

156

New equipment was designed specifically for the testing of large weighing
scales, and liquid meters dispensing corrosive liquids, both pressure and
nonpressure.

Studies were continued and recommendations to the States were made re-
garding equipment and procedures in the area of control of prepackaged
commodities. It is now estimated by the U.S. Department of Agriculture
that at least three-quarters of each retail food dollar is spent for packaged
food. In addition, many other commodites are offered at retail in package
form. With the tremendous increase in packaging, more and more weights
and measures effort will undoubtedly be devoted to package control. A
special study of the measurement practices in one of the nation's largest
manufacturers of soaps and detergents resulted in a series of recommenda-
tions that are being placed into effect. These changes will lead to a much
closer relation to the national measurement standards throughout the plants
of that organization and may serve to guide the industry to greater accuracy
in measurement activities.

A project covering new standards of weight and measure for the States is
making excellent progress. In 1836 and 1866 the Congress provided the
States with reference standards that became the basis for nationwide uni-
formity. Since then, through obsolescence and some individual purchases,
nonuniformity in the physical characteristics of the standards has developed
among the States. The Bureau's current efforts will provide a sound basis
for repeating the 19th century actions. This would bring about complete
uniformity among tHe States in weights and measures reference standards.
An entirely new stainless steel has been developed commercially that pro-
vides excellent corrosion resistance, machinability, high-gloss finish, and the
proper density for mass standards. Purchase and performance specifications
for complete sets of such standards have been drawn, bids awarded, and
prototype sets are now being fabricated. Three very special high precision
balances of a design not heretofore applied to weight calibration have been
constructed and are undergoing test. These balances are simple to manipu-
late, rapid to operate, and afford mass measurements with a precision of 1
part in 5 million (see p. 22) .

Experimental studies on liquid-capacity standards molded of glass and of
unusual design are nearing completion. Standards of this design will bring
utility, versatility, and high precision to a State laboratory. In length
standards, a highly useful length bench for testing rules, tapes, and the like has
been designed, fabricated, and tested. This device, along with a yard-and-
meter end standard and appropriate stainless tapes, will make available to
a State laboratory for the first time precise test of various length-measuring
instruments.

The Office of Weights and Measures has, as one of its basic responsibilities,
the dissemination of accurate information on units, systems, and equivalents
of weights and measures. Tables of interrelation in forms that facilitate
ready reference are published, and a large volume of inquiries are handled

157

every year. Two collections of books and other documents make up the
Weights and Measures Library — the archival collection and the reference
collection. A complete indexing operation has been under way and is
nearing completion. This library affords the staff and outside researchers
and students complete references on the history and present status of weights
and measures.

Traditionally, the National Conference on Weights and Measures has
been one of the principal means of promoting uniformity and raising per-
formance standards in weights and measures administration in the United
States. Sponsored by the Bureau, the 46th Annual Conference was held in
Washington, D.C., during the year. Thirty-five States, the District of
Columbia, Puerto Rico, Canada, and Great Britain were officially repre-
sented at this 5-day meeting. The total registered attendance was 393.

158

3. APPENDIXES

3.1. ORGANIZATION OF THE NATIONAL BUREAU OF

STANDARDS*

[The Bureau is headed by a Director who is appointed by the President with Senate
confirmation. The Director is assisted by a Deputy Director, who is responsible for
internal operations. Several Associate Directors participate in the leadership function,
coordinating related technical work across division lines, heading important policy
committees, and handling special assignments in a staff capacity. One of the Associate
Directors, in addition to being responsible for administration and support activities
of a continuing nature, is in charge of an extensive special project — planning for the
Bureau's new laboratories which are being constructed at Gaithersburg, Maryland.
In charge of the Boulder Laboratories is a Director who also has the status of Associate
Director of the Bureau. Program activities are conducted in 22 scientific divisions.
Most divisions correspond roughly to a major field of physical science or engineering,
and are divided into sections responsible for technical areas within each field. Six-
teen of the divisions are located in Washington and six in Boulder. Below the section
level, the staff is organized into project groups which may be easily regrouped.]

DIRECTOR

Allen V. Astin

DEPUTY DIRECTOR

Robert D. Huntoon

Associate Directors

C. M. Herzfeld R. S. Walleigh

A. T. McPherson Edward Wichers

I. C. SCHOONOVER W. A. WlLDHACK

F. W. Brown, Director, Boulder Laboratories

Assistants to the Director

W. S. Bussey
C. N. Coates

Special Research Group

H. P. Broida
U. Fano

Consultants to the Director

J. I. Hoffman
K. E. Shuler

Staff Advisers

NBS Reactor Program C. 0. Muehlhause

Financial Management Officer N. L. Christeller

Legal Advisor H. J. Johnson

Patent Advisor D. Robbins

Director Emeritus

Lyman J. Briggs

*Aa of September 1, 1961.

159

NBS WASHINGTON
SCIENTIFIC DIVISIONS AND SECTIONS

(In numerical order)
1. ELECTRICITY

Chief C. H.

Page

Resistance and Reactance

J. L. Thomas

Electrochemistry

W. J. Hamer

Electrical Instruments

F. M. Defandorf

Magnetic Measurements

I. L. Cooter

Dielectrics

J. D. Hoffman

2. METROLOGY

Chief A

. G. McNish

Assistant Chief

D. B. Judd

Photometry and Colorimetry

L. E. Barbrow

Refractometry

F. E. Washer

Photographic Research

C. S. McCamy

Length

B. L. Page

Engineering Metrology

I. H. Fullmer

Mass and Scale

A. G. McNish, Acting

Volumetry and Densimetry

J. C. Hughes, Acting

3. HEAT

Chief

C. M. Herzfeld, Acting

Assistant Chief for Thermodynamics

C. W. Beckett

Temperature Physics

J. F. Swindells

Heat Measurements

D. C. GlNNINGS

Cryogenic Physics

R. P. Hudson

Equation of State

J. HlLSENRATH

Statistical Physics

M. S. Green

4. RADIATION PHYSICS

Chief L. S. Taylor

X-ray

H. 0. Wyckoff

Radioactivity

W. B. Mann

Radiation Theory

L. V. Spencer, Acting

High Energy Radiation

H. W. Koch

Radiological Equipment

S. W. Smith

Nucleonic Instrumentation

L. COSTRELL

Neutron Physics

R. S. Caswell

5. ANALYTICAL AND INORGANIC CHEMISTRY

Chief H.

C. Allen, Jr.

Assistant Chief

R. G. Bates

Consultants

R. Gilchrist

C. P. Saylor

Pure Substances

F. L. Howard

Spectrochemistry

B. F. Scribner

Solution Chemistry

R. G. Bates

Standard Reference Materials

3 J. L. Hague

Applied Analytical Research

J. K. Taylor

6. MECHANICS

Chief E

1. L. Wilson

Consultants J. M.

Frankland

E. C. Lloyd

Sound

R. K. Cook

Pressure and Vacuum

D. P. Johnson

Fluid Mechanics

G. B. Schubauer

Engineering Mechanics

L. K. Irwin

Rheology

R. S. Marvin

Combustion Controls

F. R. Caldwell

160

7. ORGANIC AND FIBROUS MATERIALS
Chief G. M. Kline

Rubber

Textiles

Paper

Leather

Testing and Specifications

Polymer Structure

Plastics

Dental Research

L. A. Wood

H. F. SCHIEFER

R. B. Hobbs

J. R. Kanagy

R. D. Stiehler

N. P. Bekkedahl

F. W. Reinhart

W. T. Sweeney

Chief

Assistant Chief
Thermal Metallurgy
Chemical Metallurgy
Mechanical Metallurgy
Corrosion
Metal Physics

8. METALLURGY

L. M

Kushner, Acting

T. G. Digges

L. L. Wyman

J. A. Bennett

G. A. Ellinger

L. M. Kushner

Electrolysis and Metal Deposition

A. Brenner

9. MINERAL PRODUCTS

Chief

Assistant Chief
Consultants

Engineering Ceramics

Glass

Refractories

Enameled Metals

Crystal Growth

Physical Properties

Constitution and Microstructure

A. D. Franklin

C. H. Hahner

R. F. Geller

E. R. LlPPINCOTT

M. D. Burdick

C. H. Hahner

Vacant

W. N. Harrison

F. Ordway

A. D. Franklin, Acting

H. F. McMurdie

10. BUILDING RESEARCH

Chief
Consultant

Structural Engineering

Fire Research

Mechanical Systems

Organic Building Materials

Codes and Safety Standards

Heat Transfer

Inorganic Building Materials

D. E. Parsons
W. F. Roeser

D. Watstein

A. F. Robertson

P. R. Achenbach

W. W. Walton

R. L. Lloyd, Acting

H. E. Robinson

R. L. Blaine

11. APPLIED MATHEMATICS

Chief

Assistant Chief

Consultant
Numerical Analysis
Computation
Statistical Engineering
Mathematical Physics
Operations Research

E. W. Cannon
F. L. Alt

W. J. YOUDEN

P. Davis

D. I. MlTTLEMAN
C. ElSENHART

W. H. Pell
A. J. Goldman

12. DATA PROCESSING SYSTEMS

Chief
SEAC
PILOT

Research Information Center and Advisory
Service on Information Processing

Components and Techniques

Computer Technology

Measurements Automation

Engineering Applications

Systems Analysis

S. N. Alexander

J. F. Rafferty

P. D. Schupe

Miss M. E. Stevens

R. D. Elbourn

J. A. Cunningham, Acting

S. N. Alexander, Acting

E. Glaser

161

13. ATOMIC PHYSICS

Chief
Consultant

L. M. Branscomb
F. L. Mohler

Spectroscopy
Infrared Spectroscopy
Solid State Physics
Electron Physics
Atomic Physics

K. G. Kessler

E. K. Plyler

H. P. R. Frederikse

L. L. Marton

S. J. Smith

14. INSTRUMENTATION
Chief G. F. Montgomery

Engineering Electronics
Electron Devices
Electronic Instrumentation
Mechanical Instruments
Basic Instrumentation

G. Shapiro

C. P. Marsden

G. F. Montgomery, Acting

A. Wexler

J. Stern

15. PHYSICAL CHEMISTRY

Chief

M. B. Wallenstein

Assistant Chief
Thermochemistry
Surface Chemistry
Organic Chemistry
Molecular Spectroscopy
Molecular Kinetics
Mass Spectrometry

F. Buckley
E. J. Prosen
R. Klein

H. S. ISBELL

D. E. Mann

R. E. Ferguson

V. H. Dibeler

17. OFFICE OF WEIGHTS AND MEASURES
Chief M. W. Jensen

ADMINISTRATIVE AND SERVICE DIVISIONS

Office of Technical Information

Accounting

Personnel

Administrative Services

Shops

Supply

Management Planning

Budget

Internal Audit

Plant

NBS Library

W. R. Tilley
J. P. Menzer
G. R. Porter

H. P. Dalzell
F. P. Brown

G. B. Kefover

I. ASAY

E. Skillington

J. Seidenberg

H. Graham

Miss S. Jones

BOULDER DIVISIONS

DIRECTOR, BOULDER LABORATORIES F. W. Brown

Consultants

Math-Analysis and Computation Facility Group
Mathematical Physics and Education Director
Statistics
Astrophysics

Radio Wave Propagation

Physics of the Atmosphere

Communications Liaison Officer

CRPL Liaison and Program Development

Executive Officer and Chief of Administrative Division

Technical Information Officer

J. J. Sopka

E. H. Brown

E. L. Crow

R. N. Thomas

J. T. Jeffries

J. R. Wait

D. M. Gates

Allen Barnabei

A. H. Shapley

S. W. J. Welch

J. R. Craddock

162

81. CRYOGENIC ENGINEERING

Chief

Assistant Chief
Cryogenic Equipment
Cryogenic Processes
Properties of Materials
Cryogenic Technical Services

R. B. Scott
B. W. Birmingham

R. B. Jacobs

B. W. Birmingham

R. J. Corruccini

V. J. Johnson

82. *IONOSPHERE RESEARCH AND PROPAGATION

Chief

Assistant Chief

Assistant to Chief for Technical Planning and Coordination

Consultant

Low Frequency and Very Low Frequency Research

Ionosphere Research

Prediction Services

Sun-Earth Relationships

Field Engineering

Radio Warning Services

Vertical Soundings Research

E. K. Smith, Jr.
T. N. Gautier
R. W. Knecht
J. A. Kemper
D. K. Bailey
A. G. Jean
K. Davies
W. B. Chadwick
R. W. Knecht
H. G. Sellery
J. V. Lincoln
J. W. Wright

83. * RADIO PROPAGATION ENGINEERING

Chief K. A. Norton

Assistant Chief for Research and Development J. W. Herbstreit

Consultant — Terminal Equipment

Data Reduction Instrumentation

Radio Noise

Tropospheric Measurements

Tropospheric Analysis

Propagation-Terrain Effects

Radio Meteorology

Lower Atmosphere Physics

E. F. Florman

W. E. Johnson

W. Q. Crichlow

M. T. Decker

P. L. Rice

R. S. Kirby

B. R. Bean

M. C. Thompson, Jr.

84. RADIO STANDARDS

Chief

Assistant Chief for Radio Frequencies

Assistant Chief for Microwave Frequencies

Assistant Chief for Technical Planning and Coordination

Consultants

High-Frequency Electrical Standards

Radio Broadcast Service

Radio and Microwave Materials

Atomic Frequency and Time Interval Standards

Electronic Calibration Center

Millimeter- Wave Research L

Microwave Circuit Standards

85. *RADIO SYSTEMS

Chief R. C. Kirby

Assistant Chief D. W. Patterson
Consultant G. W. Haydon

High Frequency and Very High Frequency Research

Modulation Research

Antenna Research

Navigation Systems

J. M. Richardson
W, D. George
D. M. Kerns
E. C. Wolzien
W. W. Brown
P. F. Wacker
M. C. Selby
A. H. Morgan
J. L. Dalke
R. C. Mockler
H. W. Lance
Y. Beers, Acting
R. W. Beatty

W. F. Utlaut

W. C. Coombs

H. V. Cottony

G. Hefley

87. *UPPER ATMOSPHERE AND SPACE PHYSICS

Chief C. G. Little

Consultants R. J. Slutz

D. K. Bailey

Upper Atmosphere and Plasma Physics

Ionosphere and Exosphere Scatter

Airglow and Aurora

Ionospheric Radio Astronomy R

R. M. Gallet

K. L. Bowles

F. E. Roach

. S. Lawrence

♦These divisions comprise the Central Radio Propagation Laboratory.

163

FIELD ESTABLISHMENTS

Visual Landini

g Aids Field Laboratory

Areata, Calif.

Master Railway Track Scale Depot

Clearing, 111.

Materials Testing Laboratories:

Allentown, Pa.

Denver, Colo.

San Francisco, Calif.

Seattle, Wash.

Radio Transmitting Station WWV

Greenbelt, Md.

Radio Transmitting Station WWVL

Boulder, Colo.

Central Radio Propagation

Laboratory Field Stations :

ALASKA

COLOMBIA

NORWAY

Anchorage

Bogota**

Andenes**

Barrow

GREENLAND

OKINAWA

ANTARCTICA

Thule**

Onna**

Marie Byrd Base**

Godhavn**

Okuma**

Pole Station**

Narsarssuak**

Mirny Base (Soviet)

OKLAHOMA

Exchange Scientists

HAWAII

Altus

with Byrd Base

Maui (WWVH)

Kekaha

PANAMA CANAL ZONE

AUSTRALIA

Mt. Haleakala

Balboa**

Cook**

ICELAND

PERU

BOLIVIA

Keflavik**

Lima**

La Paz**

Reykjavik**

Jicamarca Radio
Observatory

BRAZIL, S.A.

ILLINOIS

Sao Jose dos Campos**

Long Branch

PHILIPPINE ISLANDS
Poro Point**

CANADA

INDIA

Baguio

Manitoba**

New Delhi**

PUERTO RICO

CHILE

ISRAEL

San Juan

Concepcion**

Haifa**

SOUTH AFRICA

COLORADO

JAPAN

Pretoria**

Beulah

Ohira**

Brighton

SWEDEN

Chalk Cliff Site

KANSAS

Enkoping**

Cheyenne Mtn.

Garden City

Erie

UTAH

Fritz Peak

MALAYA

Salt Lake City**

Gunbarrel Hill

Singapore**

Ha swell

VIRGINIA

Hygiene

MOROCCO

Fort Belvoir

Karval

Rabat**

Front Royal

Kendrick

Sterling

Kolb

NEBRASKA

Lafayette

Shickley

WYOMING

Marble

Bill

Marshall

NIGERIA

Table Mesa

Ibadan**

Sunset

♦♦Contract or Mutual Cooperation.

164

3.2. SUMMARY OF NBS STAFF*

Washington

Boulder

Total

Total permanent staff

2,253

457

1,020
189

3,273

Other staff* *

646

Total on payroll

2,710
282

1,209
23

3,919

Research associates and guest workers ....

305

Total working at NBS

2,992

1,232

4,224

Professional staff:

Chemists

515
336
232
94
150

237
8

192
73
35

752
344

Other

424
167
185

1,327

545

1,872

*As of June 30, 1961.

**WAE, full-time consultants, students, teachers, postdoctoral fellows, and temporary -limited employees.

3.3. FINANCIAL DATA ON NBS PROGRAM

The activities of the National Bureau of Standards are financed from
three sources: from appropriations provided by the Congress; from pay-
ments by other agencies for specific research and development tasks; and
from payments by industrial concerns, universities, research institutions,
and government agencies for specific calibration or testing services. The
following tabulation is a summary of the financial aspects of the Bureau
programs for 1961:

Program and Source of Financing

Obligations Incurred (Rounded)

Supported by NBS Appropriations:
Operating Programs:

Research & Technical Services .
Construction and Facilities Pro-
gram:

Plant and Facilities

$2, 976, 000
10,430,000

$19,578,000
13, 406, 000

Construction of Facilities

Subtotal

12, 806, 000
428, 000

Total NBS Appropriation

Supported by Other Funds:

Research and Development Pro-
grams:

Other Federal Agencies

Nongovernmental Sources

13,234,000
4, 892, 000
1, 134, 000

$32, 984, 000

Calibrations, Testing, and Standard
Samples

Reimbursable Administrative Serv-
ices

Total Supported by Other Funds .

19, 260, COO

Total Program

52, 244, 000

165

The $19,578,000 program financed by the Bureau's Research and Tech-
nical Services appropriation reflects a continuation of the major program
increase provided in 1960 and about a $1 -million increase in salary costs
due to the general pay raise.

The $2,976,000 expended in the Plant and Facilities program represents
partial progress on several important facilities authorized in 1961, as well
as completion of previously authorized facilities. The 1961 authoriza-
tions included the following:

(1) A new radio propagation research station near Lima, Peru, in

which a 6 megawatt (peak power) radar transmitter and a 25-
acre antenna array will be used to exploit the incoherent scatter
technique for atmospheric research.

(2) A $1.2-million addition to the main laboratory building at Boulder,

Colo.

(3) An atomic beam frequency standard.

(4) Design and engineering for a nuclear research reactor of the

water-moderated, enriched-fuel type, to operate initially at a
power level between 5 and 10 megawatts.

The construction of facilities obligations were for continued design effort
on the new laboratories at Gaithersburg, Md., and for the construction con-
tract for the first buildings: The Engineering Mechanics Laboratory and
the Power Plant. Appropriations provided in 1961 will also finance the
Radiation Physics Laboratory and the high-intensity linear electron
accelerator.

Total Program Levels, For a number of years the Bureau has been
attempting to achieve a more adequate level of effort on basic Bureau work
and to reverse the imbalance between that work and work for other agencies.
The following charts show the progress to date toward these objectives.

Chart I is perhaps the best index because it reflects the level of effort and
is not distorted by changes in salary rates or other cost factors. The chart
shows, for example, that in 1960 the research and development effort
financed by the NBS appropriation finally rose above the 1950 level. It
shows also that, since 1958, 50 percent of the increased effort on the Bureau's
basic responsibilities has come from staff formerly financed by other
agencies.

166

NBS TECHNICAL PROGRAM- COMPARISON OF SOURCES OF SUPPORT
I. DIRECT MAN-YEARS

3,000

2,500

2,000
to
%
gj 1,500

1,000

500

1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961

MAN-YEARS

NBS APPROP 1004 1075 1071 896 914 947 672 669 710 776 822 928 1141 1299

OTHER R&D I 1056 974 861 8 21

CALIB & SVCSJj4! £1^8 137£ 1776 ^£^1^^ 1284 1262 ^° 283 296 3 1 3

r"""

\
\

OTHER FUNDS

/
/
/

\
\
\

^,-

*0"^ """ — •.

■ NBS APPROP.

..-.1.—

CALIB. a svcs.

TOTAL

1853 2223 2442 2672 3578 3734 2402 1939 1994 2038 2122 2185 2298 243 3

•

n OBLIGATIONS

/
/
/

"**>*

•

/
/
/
f

OTHER FUNDS

/
/
/

\
\
\
\
\

1
i
1

>^-*"'

OTHER

R&D

N BS APPROP.

CALIB. 8 SVCS,

1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961

MILLIONS OF DOLLARS

NBS APPROP 6.5 7.9 7.9 7.5 7.1 7.0 5.3 5.6 6.9 8.2 9.7 12.4 17.1 19.6

OTHER R&D 1 14 8 14.2 13.7 13.2

CALIB & SVCS/^ U.7 11.6 31,7 45.6 ^ ^ ^ 13.1 16.9 ^J 3|9 k\'2 4.6

TOTAL

16.6 19.6 19.5 39.2 52,7 47.6 23.4 18.2 20.0 25.1 27.3 30.5 35.0 37.4

3.4. ADVISORY COMMITTEES

STATUTORY VISITING COMMITTEE

[Reports annually to Secretary of Commerce on NBS activities (Dates indicate expira-
tion of appointment) ]

Dr. M. J. Kelly, Former President and Chairman of the Board, Bell Telephone Lab-
oratories, Inc. (1962), Chairman
Professor F. Seitz, University of Illinois (1961)

Dr. Lloyd V. Berkner, President, Graduate Research Center, Inc. (1963)
Dr. Crawford H. Greenewalt, President, E. I. du Pont de Nemours & Co. ( 1964)
Professor Charles H. Townes, Columbia University (1965)

167

TECHNICAL ADVISORY PANELS

[Appointed by the National Academy of Sciences-National Research Council in co-
operation with the leading scientific and technical societies to advise NBS Director
in specific technical areas. Cooperating societies are: American Ceramic Society
(ACerS) ; American Chemical Society (ACS) ; American Institute of Chemical
Engineers (AIChE) ; American Institute of Electrical Engineers (AIEE) ; American
Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) ; American
Institute of Physics (AIP) ; American Society of Civil Engineers ( ASCE) ; Ameri-
can Society of Mechanical Engineers (ASME) ; Conference Board of the Mathe-
matical Sciences (CBMS) ; and Institute of Radio Engineers (IRE). Appointments
at large ( AL) . Members listed served during fiscal year 1961.]

Dr. Paul D. Foote, National Research Council, Executive Secretary

Advisory Panel to Electricity Division

Prof. W. A. Lewis, Illinois Institute of Technology, Chairman (AIEE)

Prof. Norman I. Adams, Jr., Yale University (AIP)

Dr. William G. Amey, Leeds & Northrup Company (AIEE)

Dr. Richard M. Bozorth, Bell Telephone Laboratories (AIP)

Dr. John Brainerd, University of Pennsylvania (IRE)

Prof. Henry B. Linford, Columbia University (ACS)

Mr. J. T. Lusignan, The Ohio Brass Company (AIEE)

Dr. Ernest Weber, Polytechnic Institute of Brooklyn (AIEE)

Advisory Panel to Metrology Division

Dr. Brian O'Brien, Pomfret, Conn., Chairman (AIP)
Prof. Is ay A. Balinkin, University of Cincinnati (ACerS)
Prof. Clarence E. Bennett, University of Maine (AIP)
Dr. Alsoph H. Corwin, The Johns Hopkins University (ACS)
Mr. C. L. Crouch, Illuminating Engineering Society (AL)
Mr. A. M. Dexter, Pratt and Whitney Company, Inc. (AL)
Dr. Robert E. Hopkins, Tropel, Inc. (AL)
Mr. Floyd W. Hough, Arlington, Virginia (ASCE)
Mr. J. J. Moran, Kimble Glass Company (ACerS)
Mr. Louis Polk, The Sheffield Corporation (ASME)
Prof. John Strong, The Johns Hopkins University (AIP)
Dr. J. H. Webb, Eastman Kodak Company (AIP)

Advisory Panel to Heat Division

Prof. Joseph E. Mayer, University of California, Chairman (ACS)

Prof. James A. Beattie, Massachusetts Institute of Technology (AIP)

Prof. Henry A. Fairbank, Yale University (AIP)

Prof. Joseph Kestin, Brown University (ASME)

Dean R. B. Lindsay, Brown University (AIP)

Prof. Glenn C. Williams, Massachusetts Institute of Technology (AIChE)

Advisory Panel to Radiation Physics Division

Dr. H. M. Parker, General Electric Company, Chairman (AIP)

Dr. Everitt P. Blizard, Oak Ridge National Laboratory (AIP)

Dr. Martin Deutsch, Massachusetts Institute of Technology (AIP)

Dr. A. 0. Hanson, University of Illinois (AIP)

Dr. William A. Higinbotham, Brookhaven National Laboratory (IRE)

Prof. Harold A. Lamonds, North Carolina State College (AIEE)

Dr. Leonard Schiff, Stanford University (AIP)

168

Advisory Panel to Analytical and Inorganic Chemistry Division

Dr. T. Ivan Taylor, Columbia University, Chairman (ACS)

Dr. Clark E. Bricker, Princeton University (ACS)

Dr. N. D. Coggeshall, Gulf Research and Development Company (AIP)

Dr. W. D. Cooke, Cornell University (ACS)

Dr. Herbert A. Laitinen, University of Illinois (ACS)

Dr. W. Wayne Meinke, University of Michigan (ACS)

Dr. J. R. Ruhoff, Malinckrodt Chemical Company (ACS)

Dr. Charles E. White, University of Maryland (ACS)

Advisory Panel to Mechanics Division

Dean Dana Young, Yale University, Chairman (ASME)

Prof. Lynn S. Beedle, Lehigh University (ASCE)

Prof. S. R. Beitler, Ohio State University (ASME)

Prof. Arthur T. Ippen, Massachusetts Institute of Technology (ASCE)

Dr. Harry F. Olson, Radio Corporation of America (AIP)

Prof. Jesse Ormondroyd, University of Michigan (ASME)

Dr. Milton Plesset, California Institute of Technology (AIP)

Advisory Panel to Organic and Fibrous Materials Division

Dr. Norman A. Shepard, Stamford, Conn., Chairman (ACS)

Dr. J. H. Dillon, Textile Research Institute (AIP)

Dr. Milton Harris, The Gillette Company (ACS)

Prof. Herman F. Mark, Polytechnic Institute of Brooklyn (AIP)

Dr. C. G. Overberger, Polytechnic Institute of Brooklyn (ACS)

Dr. J. F. Downie Smith, Carrier Research and Development Co. (ASME)

Advisory Panel to Metallurgy Division

Mr. Francis L. LaQue, International Nickel Co., Chairman (ACS)

Dr. D. J. Dienes, Brookhaven National Laboratory (AIP)

Mr. A. R. Lytle, Linde Company (AIME)

Dean E. F. Osborn, Pennsylvania State University (ACerS)

Dr. Joseph A. Pask, University of California (ACerS)

Dr. Albert J. Phillips, American Smelting and Refining Co. (AIME)

Mr. D. B. Rossheim, M. W. Kellogg Corp. (ASME)

Advisory Panel to Mineral Products Division

Mr. Karl Schwartzwalder, General Motors Corp., Chairman (ACerS)

Mr. Herbert Insley, Washington, D.C. (ACerS)

Dr. James R. Johnson, Minnesota Mining and Manufacturing Co. (ACerS)

Dr. Norbert J. Kreidl, Bausch and Lomb Optical Co. (ACerS)

Dean E. F. Osborn, Pennsylvania State University (ACerS)

Prof. Pierce Selwood, Northwestern University (ACS)

Dr. Robert B. Sosman, Rutgers, The State University (ACerS)

Prof. Bertram E. Warren, Massachusetts Institute of Technology (AIP)

Dr. Clarence Zener, Westinghouse Electric Corp. (AIME)

Advisory Panel to Building Research Division

Dr. W. C. Hansen, Valparaiso, Indiana, Chairman (ACS)

Prof. Jesse H. Day, Ohio University (ACS)

Prof. Robert A. Hechtman, George Washington University (ASCE)

Prof. James T. Lendrum, University of Florida ( AIA)

Mr. Paul V. Johnson, Structural Clay Products Research Foundation (ACerS)

Dean Warren L. McCabe, Polytechnic Institute of Brooklyn (AICE)

Dr. John S. Parkinson, Johns-Manville Products Corp. (AIP)

Prof. E. R. Queer, Pennsylvania State University (AL)

Mr. Raymond C. Reese, Toledo, Ohio (ASCE)

616114 O— ©1 12 169

Advisory Panel to Applied Mathematics Division

Prof. Mark Kac, Cornell University, Chairman (CBMS)

Prof. A. H. Bowker, Stanford University (AL)

Prof. Jesse Douglas, City College of New York ( AL)

Prof. William Feller, Princeton University (CBMS)

Dr. Alston S. Householder, Oak Ridge National Laboratory (CBMS)

Prof. B. 0. Koopman, Columbia University (CBMS)

Prof. Philip M. Morse, Massachusetts Institute of Technology (CBMS)

Prof. J. L. Walsh, Harvard University (CBMS)

Advisory Panel to Data Processing Systems Division

Dr. Alston S. Householder, Oak Ridge National Laboratory, Chairman (CBMS)

Mr. John C. McPherson, International Business Machines Corporation (IRE)

Prof. Charles L. Miller, Massachusetts Institute of Technology (ASCE)

Prof. Raymond Pepinsky, Pennsylvania State University (AIP)

Prof. William H. Radford, Massachusetts Institute of Technology (IRE)

Prof. Morris Rubinoff, University of Pennsylvania (AIEE)

Advisory Panel to Atomic Physics Division

Prof. R. H. Dicke, Princeton University, Chairman (AIP)

Prof. Benjamin Bederson, New York University (AIP)

Prof. Jesse L. Greenstein, Mount Wilson and Palomar Observatories (AL)

Prof. Vernon W. Hughes, Sloane Laboratory (AIP)

Prof. Mark G. Ingrham, Universiy of Chicago (AIP)

Dr. Benjamin Lax, Massachusetts Institute of Technology (AIP)

Prof. Peter Franken, University of Michigan (AIP)

Dr. M. K. Wilson, Tufts University (ACS)

Dr. David Z. Robinson, Baird Atomic Incorporated (AIP)

Advisory Panel to Instrumentation Division

Mr. R. W. Larson, General Electric Research Laboratories, Chairman (AIEE)

Dr. A. 0. Beckman, Beckman Instruments, Inc. (AL)

Mr. D. G. Fink, Philco Corporation (IRE)

Dr. R. J. Jeffries, Data-Control Systems, Inc. (AL)

Colonel J. Z. Millar, Western Union Telegraph Company (AIEE)

Mr. Leon Podolsky, Sprague Electric Company (IRE)

Advisory Panel to Physical Chemistry Division

Prof. Henry Eyring, University of Utah, Chairman (ACS)
Dr. A. 0. Allen, Brookhaven National Laboratory (ACS)
Prof. Paul Cross, University of Washington (ACS)
Prof. Hans H. Jaffj6,, University of Cincinnati (ACS)
Dr. Daniel R. Stull, The Dow Chemical Company (ACS)

Advisory Panel to Cryogenic Engineering Division

Dr. Charles Squire, United Aircraft Corporation, Chairman (AIP)

Prof. S. C. Collins, Massachusetts Institute of Technology (ASME)

Mr. Allen Latham, Jr., Arthur D. Little Company ( AIChE)

Dr. Hugh M. Long, Tonawanda, New York (AIP)

Dr. Clyde McKinley, Air Products Incorporated (AIChE)

Dr. Loyd B. Nesbitt, General Electric Laboratory (AIP)

170

Advisory Panel to Central Radio Propagation Laboratory

Prof. Arthur H. Waynick, Pennsylvania State University, Chairman (IRE)

Mr. Stuart L. Bailey, Washington, D.C. (IRE)

Prof. Henry G. Booker, Cornell University (IRE)

Mr. A. B. Crawford, Bell Telephone Laboratories (AL)

Dr. R. A. Helliwell, Stanford University (IRE)

Dr. S. W. Herwald, Westinghouse Electric Corporation (AIEE)

Dr. John S. Smyth, Smyth Research Associates (AIP)

Dean George Town, Iowa State University (AIEE)

Dr. Albert D. Wheelon, Space Technology Laboratories, Inc. (IRE)

Advisory Panel to Radio Standards Division

Prof. Arthur A. Oliner, Polytechnic Institute of Brooklyn, Chairman (IRE)

Prof. Walter Gordy, Duke University (AIP)

Prof. E. C. Jordan, University of Illinois (IRE)

Prof. W. A. Lewis, Illinois Institute of Technology (AIEE)

Dr. John C. Simons, National Research Corporation (IRE)

Mr. Robert C. Sprague, Sprague Electric Company (AIEE)

ADVISORY COMMITTEE ON ENGINEERING AND RELATED

STANDARDS

[Members are nominated by the American Standards Association (ASA) and the
American Society for Testing Materials (ASTM) ]

Mr. W. A. Wildhack, National Bureau of Standards, Chairman

Dr. A. A. Bates, Portland Cement Association (ASTM)

Admiral George F. Hussey, Jr., USN (Ret), American Standards Association (ASA)

Mr. F. L. LaQue, International Nickel Company (ASTM)

Mr. John W. McNair, American Standards Association (ASA)

Mr. N. L. Mochel, Westinghouse Electric Company (ASTM)

Mr. John R. Townsend, American Standards Association (ASA)

ADVISORY COMMITTEE ON CALIBRATION AND MEASUREMENT

SERVICES

[Members are appointed on the basis of their broad personal knowledge of industrial
measurement problems]

Mr. W. A. Wildhack, National Bureau of StandardsrChairman

Dr. W. G. Amey, Leeds & Northrup Company

Mr. H. C. Biggs, Sandia Corporation

Mr. E. J. Brazill, The Martin Company

Mr. C. H. Brumley, Bausch & Lomb Incorporated

Col. William J. Darmody, USA (Ret) , The Sheffield Corporation

Mr. Ivan G. Easton, General Radio Company

Mr. L. H. LaForge, Jr., Sylvania Electronics Systems

Mr. L. B. Wilson, Sperry Gyroscope Company

Mr. A. J. Woodington, Convair Astronautics

WEIGHTS AND MEASURES ADVISORY COMMITTEE

[Members are nominated by the National Conference on Weights and Measures]

Dr. A. T. McPherson, National Bureau of Standards, Chairman

Prof. L. J. Gordon, Weights and Measures Research Center, Denison University

Mr. Rollin E. Meek, State Board of Health, Indiana

Commissioner P. C. Brinkley, State Department of Agriculture and Markets, Virginia

Mr. L. T. Gustafson, Creamery Package Manufacturing Company

Mr. J. E. Moss, American Petroleum Institute

Mr. E. C. Westwood, City Sealer of Weights and Measures, Salt Lake City, Utah

171

3.5. AWARDS AND HONORS

Recognition of the Bureau's contributions to science and technology often takes the
form of awards and honors from government, academic, professional, and industrial
groups. The following list reflects such recognition bestowed on Bureau staff members
during fiscal year 1961.

RECIPIENT

Ambler, Ernest

Astin, A. V.
Bailey, Dana K.
Brlnner, Abner

Briggs, Lyman J.
(Director Emeritus)
Davis, P. J.
Deitz, Victor R.
Douglas, Charles A.
Frederikse, H. P. R.
Havens, Clyde E.

Hayward, Evans
Kline, G. M.
Knudse.»j, Fred
Koch, H. William
Shapiro, Gustave
Sitterly, C. M.
Wait, James R.

AWARD
Arthur S. Flemming Award of the Junior Chamber of Commerce, Washington,

D.C.
Lifetime Honorary Membership by the Instrument Society of America
The University of Arizona's Seventy-Fifth Anniversary Medallion of Merit
Hothersall Memorial Lecturer 1961 of the Institute of Metal Finishing
Blum Award from the American Electroplaters' Society
The President's Citation from the Franklin Institute of the State of Pennsylvania

for his loyal and valued services to the Institute
National Academy of Sciences Annual Award for Scientific Achievement
Achievement Award in Sugar Technology by the Sugar Industry Technicians
Elected a Fellow in the Illuminating Engineering Society
Fellowship from the John Simon Guggenheim Memorial Foundation
Certificate of appreciation by the General Committee of the Division of Pro-
duction of the American Petroleum Institute
Fellowship from the John Simon Guggenheim Memorial Foundation
Elected Director of the American Society for Testing Materials
Edgar Orton Award by American Ceramic Society
Alumnus of the Year, Queens College
Elected a Fellow in the Institute of Radio Engineers
Federal Woman's Award by Civil Service Commission
RESA Boulder Scientist Award

DEPARTMENT OF COMMERCE MERITORIOUS SERVICE AWARDS

RECIPIENT
Cavallo, Lucy M.
Christeller, Norman L.
Cottony, Herman V.
Couch, Dwight E.
Cutkosky, Robert D.
Engen, Glenn F.
Glaze, Francis W.
Grote, William
Kipps, Charles B.
Leslie, Robert T.
PoKempner, Minadora

Saylor, Charles P.
Smith, Jack C

TORGENSEN, JOHN L.

Wright, John W.

Joint Award :

Greenspan, Martin
Tschiegg, Carl E.

Group Award :

Chidester, Raymond
Koepper, Walter
Matway, John
Stadler, William

TECHNICAL AREA
Radiation physics
Fiscal management
Antenna research

Electroplating metals and coatings
Electrical measurements and standardization
Microwave power standards
Analytical chemistry
Instrument craftsmanship
Procurement of supplies and equipment
Fractional distillation
Frequency allocation, frequency usage, and specifications for the design of

communications equipment
Microscopical techniques for the evaluation of pure substances
Textile physics

Growth of single crystals and mechanisms of purification
Ionosphere research

Physics of sound in water

Mechanical support for the development of high precision instruments

172

DEPARTMENT OF COMMERCE EXCEPTIONAL SERVICE AWARDS

RECIPIENT TECHNICAL AREA

Bowles, Kenneth L. Ionosphere and exosphere scatter

Branscomb, Lewis M. Atomic processes of stellar atmospheres, the terrestrial ionosphere, and inter-

planetary space
Brown, Frederick W. Administration of major scientific research programs

Craig, D. Norman Accurate determination of the faraday

Digges, Thomas G. Metallurgy

Mockler, Richard C. Atomic frequency and time standards

Pararas, John Unique extra high vacuum and very low temperature laboratory equipment

Roach, Franklin E. Upper atmosphere physics

Schoonover, Irl C. Materials research, program and organization planning, development and utili-

zation of scientists

3.6. EDUCATION AND TRAINING PROGRAM

The Employee Development Program, oriented to the education and train-
ing needs of all staff members, is directed toward improving the skills and
knowledge of the staff, increasing efficiency in the conduct of assigned duties,
and preparing staff members in a systematic fashion for increased respon-
sibilities. This program is implemented through two major educational
media: the NBS Graduate School, and training through non-Government
facilities. The program covers educational levels up through postdoctoral
research and includes general staff development courses.

An average of 40 courses a year are offered in the curriculum of the NBS
Graduate School, including graduate and undergraduate courses in the
physical sciences, mathematics, and certain branches of engineering; and
a series of scientific colloquia and seminars led by research leaders from the
Bureau staff and from other research centers in this country and abroad.
Educational counseling and a program of thesis accreditation are provided.
A series of general staff development courses is also offered through the
Graduate School. Typical courses in this category are scientific Russian,
mathematical symbolism and terminology for clerical staff, and mechanical
drawing.

The NBS Educational Committee determines course offerings through
periodic need surveys. The curriculum is divided into NBS in-hours and
NBS university-sponsored out-of-hours courses and is flexible to meet the
varied and changing needs of the staff. For example, the Technician Career
Program, established in 1960, helps to increase job efficiency and offers
broader educational opportunities for subprofessional laboratory personnel.

Since the establishment of the Graduate School in 1908, more than 16,700
registrations have been recorded, and 272 graduate degrees have been
awarded by 42 different universities, partly on the basis of credits obtained,
or thesis work carried on, through the Graduate School. During the past
year there were 1,217 registrations in 78 courses offered at the Washington
and Boulder Laboratories. Of these registrations 560 were from the Army's
Diamond Ordnance Fuze Laboratories and other government agencies in
the Washington area.

173

Three major training programs are sponsored by the Bureau through non-
Government facilities under authority of the Government Employees' Train-
ing Act of 1958. These are:

1. Full-time (3 to 12 months) postdoctoral study and research assign-

ments at universities and research centers, both in this country
and abroad.

2. Full-time (less than 3 months) attendance at institutes, seminars,

short concentrated courses, workshops, etc. Generally, these
are offered through the educational facilities of major universities
and industrial laboratories throughout the country.

3. Part-time, job-related, academic courses at local educational insti-

tutions, generally in early evening classes.

Non-Government facilities were used to train 262 staff members in 1961.
Fourteen selected career scientists were sent on full-time research assign-
ments to universities and research centers. Forty-one staff members, pri-
marily scientists and subprofessional laboratory personnel, attended short
concentrated courses and training programs at universities and in industry.
In addition, 207 employees, largely from technical divisions, attended job-
related courses at local educational facilities under the tuition reimbursement
plan. The Bureau paid full salaries and expenses for participants in ap-
proved full-time non-Government training programs. These included tui-
tion, related fees, travel, and per diem, as well as transportation of family
and household effects for long-term training.

Each summer the Bureau sponsors a student trainee program open to
college students majoring in the physical sciences, mathematics, and cer-
tain branches of engineering. An integrated work-study program, this
activity includes lectures, tours, demonstrations, supervised laboratory as-
signments, and professional counseling. The purpose of the program is to
acquaint young people with career opportunities in scientific research at
NBS and to prepare select students for such careers. Approximately 220
students, representing 60 colleges and universities, participated in the 1961
summer student programs in Washington and Boulder; 130 of these were
returnees from previous summers. The new group included eight outstand-
ing high school students who had obtained recognition through the Westing-
house Science Talent Search or other national science competition.

The Bureau, in collaboration with the National Research Council, offers
postdoctoral resident research associateships to young scientific investigators
of unusual ability. Associates are given an opportunity for advanced train-
ing in basic research in the various branches of the physical and mathe-
matical sciences. While acquiring basic knowledge, they have opportuni-
ties for developing new scientific approaches and laboratory skills, thus
advancing scientific knowledge. Associateships are limited to 20 new ap-
pointments each year and are tenable at both the Washington and Boulder
Laboratories.

174

Weekly Scientific Staff Meetings, which run from September through
May, are also included in the Bureau's educational program. The Staff
Meetings are of a less specialized nature than colloquia and seminars offered
in the Graduate School, and are open to all professional staff members of
the Bureau. They are also regularly attended by scientific personnel from
neighboring laboratories. The lectures, which are designed to keep Bureau
personnel abreast of current developments in the various fields, are given
by members of the staff and by scientists from universities and other labora-
tories in the United States and abroad. Lectures by members of the Bureau
staff include a yearly report to the staff by the Director, lectures on current
research of broad general interest to other members of the staff, reports by
staff members on international meetings, and reports from fellowship scien-
tists on research work at other foreign and domestic institutions. About
two-thirds of the program is devoted to lectures by guest scientists.

3.7. COOPERATIVE RESEARCH WITH INDUSTRY

The Bureau's Research Associate Plan, a cooperative program with
American industry, has resulted in many significant developments in science
and technology. Under this plan, technical, industrial, and commercial or-
ganizations can support work at the Bureau on projects that are of special
interest to them, yet are of sufficient general interest to justify use of gov-
ernment facilities. These projects must also be important from the stand-
point of the Nation's sum total of technological knowledge. Supporting
industries donate both funds and personnel for the projects. At the present
time 11 groups are supporting research associates at NBS in the following
areas:

Sponsor Field of Activity

American Dental Association Dental research.

American Society for Testing Materials Cement reference laboratory.

American Standards Association Codes, specifications, and standards.

Asphalt Roofing Industry Bureau Asphalt roofing research.

Bone Char Research Project, Inc Studies of adsorption and adsorbents.

Calcium Chloride Association Hydration of portland cement.

NBS-Joint Committee on Chemical Analysis by Standard X-ray diffraction powder

Powder Diffraction Methods: ASTM, Ameri- patterns,
can Crystallographic Assoc, Institute of
Physics (British), National Assoc, of Corro-
sion Engineers.

Porcelain Enamel Institute Development of standard tests.

Sinclair Oil Company Thermoconductivity of thin films.

An important and similar area of cooperation between the Bureau and
industry is the program authorized in 1950 by Public Law 619 under which
the Bureau is authorized to accept funds for the purpose of furthering its
work. This arrangement permits individuals as well as technical, indus-
trial, and commercial organizations to support work at the Bureau when the
results are expected to be of value to the general public.

175

During the past year eight projects were supported by gifts from six
organizations as follows:

Gift-Supported Projects

Donor Field of Activity

American Iron and Steel Institute Durability of steel pilings.

American Iron and Steel Institute Ship plate steels.

American Iron and Steel Institute Standard samples program.

Corrosion Research Council of the Engineering Reactions at metal surfaces and

Foundation on stress corrosion.

Edward Orton, Jr., Ceramic Foundation Research in clays.

Expanded Shale, Clay and Slate Institute Shale aggregate.

Georgetown University Variable heart pump.

National Electrical Manufacturers Association Refrigerator safety devices.

3.8. PUBLICATIONS AND PATENTS

Publications in the Bureau's Series*

Journal of Research. Contains full research papers, including laboratory data, ex-
perimental procedures, and theoretical and mathematical analyses. Advances in meas-
urement standards and techniques . . . physical constants . . . properties of materials
. . . instrumentation ... radio propagation.

The Journal is published in four separate sections . . .

A. Physics and Chemistry — issued six times a year.

B. Mathematics and Mathematical Physics — issued quarterly.

C. Engineering and Instrumentation — issued quarterly.

D. Radio Propagation — issued six times a year.

The papers listed below have appeared in the four-section Journal since July 1960.

Volume 64A (Phys. and Chem.), No. 4 (July-Aug. 1960)

Gamma irradation of hexafluorobenzene, R. E. Florin, L. A. Wall, and D. W. Brown.
Behavior of isolated disturbances superimposed on laminar flow in a rectangular pipe,

G. C. Sherlin.
Standard of spectral radiance for the region of 0.25 to 2.6 microns, R. Stair, R. G.

Johnston, and E. W. Halbach.
Photovoltaic effect produced in silicon solar cells by X- and gamma rays, K. Scharf.
Phase equilibria in systems involving the rare-earth oxides. Part I. Polymorphism of

the oxides of the trivalent rare-earth ions, R. S. Roth and S. J. Schneider.
Phase equilibria in systems involving the rare-earth oxides. Part II. Solid state

reactions in trivalent rare-earth oxide systems, S. J. Schneider and R. S. Roth.
Some observations on the calcium aluminate carbonate hydrates, E. T. Carlson and H. A.

Berman.
Acid dissociation constant and related thermodynamic quantities for triethanolammo-

nium ion in water from 0 to 50 °C, R. G. Bates and G. F. Allen.
Ionization constants of four dinitrophenols in water at 25 °C, R. A. Robinson, M. M.

Davis, M. Paabo, and V. E. Bower.
Dissociation constant of anisic (p-methoxy benzoic) acid in the system ethanol-water at

25 °C, E. E. Sager and V. E. Bower.
Preparation of sulfur of high purity, T. J. Murphy, W. S. Clabaugh. and R. Gilchrist.
Tritium-labeled compounds IV. D-glucose-6-?, D-xylose-5-f, and D-mannitol-1-f. H. S.

Isbell, H. L. Frush, and J. D. Moyer.
Tritium-labeled compounds V. radioassay of both carbon-14 and tritium in films, with

a proportional counter, H. S. Isbell, H. L. Frush, and N. B. Holt.

♦Publications in these series are available, unless otherwise indicated, from the Superintendent of Docu-
ments, U.S. Government Printing Office, Washington 25, D.C. For a discussion of the publications program
see p. 18.

176

Volume 64A (Phys. and Chem.), No. 5 (Sept.-Oct. 1960)

Infrared spectrum of hydrobromic acid, E. K. Plyler.

Determination of the value of the faraday with a silver-perchloric acid coulometer,

D. N. Craig, J. I. Hoffman, C. A. Law, and W. J. Hamer.

Systems silver iodide-sodium iodide and silver iodide-potassium iodide, G. Burley

and H. E. Kissinger.
Conformations of the pyranoid sugars. III. Infrared absorption spectra of some

acetyiated aldopyranosides, R. S. Tipson and H. S. Isbell.
Dissociation constant of 4-aminopyridinium ion in water from 0 to 50 °C and related

thermodynamic quantities, R. G. Bates and H. B. Hetzer.
Tritium-labeled compounds VI. Alditols-1-f and alditols-2-f. H. L. Frush, H. S.

Isbell, and A. J. Fatiadi.

Volume 64A (Phys. and Chem.), No. 6 (Nov.-Dec. 1960)

The spectrum of singly ionized atomic iodine (I n), W. C. Martin and C. H. Corliss.

The third spectrum of gold ( Au in) , L. Iglesias.

Tolerances for layer thicknesses in dielectric multilayer coatings and interference filters,

K. D. Mielenz.
Note on particle velocity in collisions between liquid drops and solids, 0. G. Engel.
Resistance of white sapphire and hot-pressed alumina to collision with liquid drops,

0. G. Engel.
Note on the thermal degradation of polytetrafluoroethylene as a first-order reaction,

S. L. Madorsky and S. Straus.
Heat of formation of titanium trichloride, W. H. Johnson, A. A. Gilliland. and

E. J. Prosen.

Heat of formation of decaborane, W. H. Johnson, M. V. Kilday, and E. J. Prosen.
Ultra low-conductivity water by electrophoretic ion exclusion, W. Haller and H. C.

Duecker.
Spectrophotometric determination of the ionization constant of dimethylpicric acid

(2, 4, 6-trinitro-3,5-xylenol) in water at 25 °C, M. M. Davis, M. Paabo, and R. A.

Robinson.
Spectrophotometric determination of the ionization constant of 2,4,6-trinitro-ra-cresol in

water at 25 °C, M. M. Davis and M. Paabo.
Method for the separation of titanium, zirconium, iron, and aluminum from one another

and for their subsequent determination, T. J. Murphy, W. S. Clabaugh, and

R. Gilchrist.

Volume 65A (Phys. and Chem.), No. 1 (Jan.-Feb. 1961)

Faint lines in the arc spectrum of iron (Fe i), C. C. Kiess, V. C. Rubin, and C. E. Moore.

Infrared absorption of spectra of some 1-acetamido pyranoid derivatives and reducing,
acetyiated pyranoses, R. S. Tipson and H. S. Isbell.

Monolayers of linear saturated succinate polyesters and air-liquid interfaces, W. M. Lee,
J. L. Shereshefsky, and R. R. Stromberg.

Heat of formation of beryllium chloride, W. H. Johnson and A. A. Gilliland.

Heat of decomposition of potassium perchlorate, W. H. Johnson and A. A. Gilliland.

Heats of formation of lithium perchlorate, ammonium perchlorate, and sodium per-
chlorate, A. A. Gilliland and W. H. Johnson.

Heat of formation of N-dimethylaminodiborane, W. H. Johnson, I. Jaffe and E. J. Prosen.

Separation of hafnium from zirconium by anion exchange, J. L. Hague and L. A.
Machlan.

Reaction of sulfur, hydrogensulfide, and accelerators with propylene and butadiene,

F. J. Linnig, E. J. Parks, and L. A. Wall.

Volume 65A (Phys. and Chem.), No. 2 (Mar.-Apr. 1961)

Mass spectra of some deuteroethanes, E. I. Quinn and F. L. Mohler.

Heats of hydrolysis and formation of potassium borohydride, W. H. Johnson, R. H.

Schumm, I. H. Wilson, and E. J. Prosen.
Heat of combustion of borazine B3N3H6, M. V. Kilday, W. H. Johnson, and E. J. Prosen.
Thermodynamic properties of thorium dioxide from 298 to 1,200 °K, A. C. Victor and

T. B. Douglas.
Calculated energy dissipation distribution in air by fast electrons from a gun source,

J. E. Crew.
Vitrons as flow units in alkali silicate binary glasses, L. W. Tilton.
Tetragermanates of strontium, lead, and barium of formula type AB40B, C. R. Robbins

and E. M. Levin.

177

Volume 65A (Phys. and Chem.), No. 3 (May-June 1961)

International practical temperature scale of 1948. Text revision of 1960, H. F.

Stimson.
Evaluation of the NBS unit of resistance based on a computable capacitor, R. D.

Cutkosky.
Wavelengths and intensities in the first spectrum of bromine, 2000 to 13000 A, J. L. Tech

and C. H. Corliss.
Torsional resonance vibrations of uniform bars of square cross section, W. E. Tefft

and S. Spinner.
Infrared studies of aragonite, calcite, and vaterite type structures in the borates, car-
bonates, and nitrates, C. E. Weir and E. R. Lippincott.
Dielectric properties of polyamides: polyhexamethylene adipamide and polyhexamethyl-

ene sebacamide, A. J. Curtis.
Heat of formation of calcium aluminate monocarbonate at 25 °C, H. A. Berman and

E. S. Newman.
Thermodynamic constants for association of isomeric chlorobenzoic and toluic acids

with 1,3-diphenylguanidine in benzene, M. M. Davis and H. B. Hetzer.
Heats of combustion and formation of trimethylborane, triethylborane, and tri-rc-butyl-

borane, W. H. Johnson, M. V. Kilday, and E. J. Prosen.
Pyrolysis of linear copolymers of ethylene and propylene, S. Straus and L. A. Wall.
Pyrolysis of fluorocarbon polymers, L. A. Wall and S. Straus.
Preparation of fluoro- and bromofluoroaryl compounds by copyrolysis of bromofluoral-

kanes, L. A. Wall, J. E. Fearn, W. J. Pummer, and R. E. Lowry.
Thermal stability of polydivinylbenzene and of copolymers of styrene with divinyl-

benzene and with tribinylbenzene, S. Straus and S. L. Madorsky.
Conformations of the pyranoid sugars. IV. Infrared absorption spectra of some fully

acetylated pyranoses, R. S. Tipson and H. S. Isbell.
A standard for the measurement of the pH of blood and other physiological media,

V. E. Bower, M. Paabo, and R. G. Bates.

Volume 64B (Math, and Math. Phys.), No. 3 (July-Sept. 1960)

Electric polarizability of a short right circular conducting cylinder, T. T. Taylor.
Distribution of quantiles in samples from a bivariate population, M. M. Siddiqui.
Split Runge-Kutta method for simultaneous equations, J. R. Rice.
A reduction formula for partitioned matrices, E. V. Haynsworth.

Selected bibliography of statistical literature, 1930 to 1957: III. Limit theorems,
L. S. Deming.

Volume 64B (Math, and Math. Phys.), No. 4 (Oct.-Dec. 1960)

Magnetic polarizability of a short right circular conducting cylinder, T. T. Taylor.
Accuracy of Monte Carlo methods in computing finite Markov chains, N. W. Bazley

and P. J. Davis.
Error bounds in the Rayleigh-Ritz approximation of eigenvectors, H. F. Weinberger.
Sequence transformations based on Tchebycheff approximations, J. R. Rice.
Numerical solution of the frequency equations for the flexural vibration of cvlindrical

rods, W. E. Tefft.

Volume 65B (Math, and Math. Phys.), No. 1 (Jan.-Mar. 1961)

On transient solutions of the "baffled piston" problem, F. Oberhettinger.

Special types of partitioned matrices, E. V. Haynsworth.

Bound for the P-condition number of matrices with positive roots, P. J. Davis, E. V.

Haynsworth, and M. Marcus.
Some computational problems involving integral matrices, O. Taussky.
Computational problem concerning the Hilbert matrix, J. Todd.
Index to the distributions of mathematical statistics, F. A. Haight.
Selected bibliography of statistical literature, 1930 to 1957: IV. Markov chains and

stochastic processes, L. S. Deming and D. Gupta.

Volume 65B (Math, and Math. Phys.), No. 2 (Apr.-June 1961)

Optimal approximation for functions prescribed at equally spaced points, H. F.

Weinberger.
Truncations in the method of intermediate problems for lower bounds to eigenvalues.

N. W. Bazley and D. W. Fox.

178

Comparison theorems for symmetric functions of characteristic roots, M. Marcus.

Some properties of the empirical distribution function of a random process, M. M.

Siddiqui.
Another extension of Heinz's inequality, M. Marcus.
Mean motions in conditionally periodic separable systems, J. P. Vinti.
Some boundary value problems involving plasma media, J. R. Wait.

A new decomposition formula in the theory of elasticity, J. H. Bramble and L. E. Payne.
Pointwise bounds in the Cauchy problem of elastic plates, L. E. Payne.

Volume 64C (Eng. and Instr.), No. 3 (July-Sept. 1960)

A new method of measuring gage blocks, J. B. Saunders.

Gage blocks of superior stability: initial developments in materials and measurement,
M. R. Myerson, T. R. Young, and W. R. Ney.

Variation of resolving power and type of test pattern, F. E. Washer and W. P. Tayman.

A multiple isolated-input network with common output, C. M. Allred and C. C. Cook.

Phase angle master standard for 400 cycles per second, J. H. Park and H. N. Cones.

Disturbances due to the motion of a cylinder in a two-layer liquid system, L. H. Car-
penter and G. H. Keulengan.

Volume 64C (Eng. and Instr.), No. 4 (Oct.-Dec. 1960)

Error analysis of a standard microwave phase shifter, G. E. Schafer and R. W. Beatty.

A method of controlling the effect of resistance in the link circuit of the Thomson or
Kelvin double bridge, D. Ramaley.

Automatic precise recording of temperature, G. S. Ross and H. D. Dixon.

Gimbal device to minimize the effects of off-center loading on balance pans, H. A. Bow-
man and L. B. Macurdy.

Response of microchemical balances to changes in relative humidity, H. E. Aimer.

Chemical changes occurring during the weathering of two coating-grade asphalts,
S. H. Greenfeld.

Characteristics of fifteen coating-grade asphalts, S. H. Greenfeld.

Volume 65C (Eng. and Instr.), No. 1 (Jan.-Mar. 1961)

Electronic scanning microscope for a spectrographic plate comparator, M. L. Kuder.
Viscoelastometer for measurement of flow and elastic recovery, R. J. Overberg and

H. Leaderman.
An ultra low frequency bridge for dielectric measurements, D. J. Scheiber.
The Ephi system for VLF direction finding, G. Hefley, R. F. Linfield, and T. L. Davis.
Fast counting of alpha particles in air ionization chambers, Z. Bay, F. D. McLernon,

and P. A. Newman.
X-ray diffraction measurement of intragranular misorientation in alpha brass subjected

to reverse plastic strain, C. J. Newton and H. C. Vacher.
Enthalpy and specific heat of nine corrosion-resistant alloys at high temperatures,

T. B. Douglas and A. C. Victor.
Determination of minor constituents in low-alloy steels by X-ray spectroscopy, R. E.

Michaelis, R. Alvarez, and B. A. Kilday.

Volume 65C (Engr. and Instr.), No. 2 (Apr.-June 1961)

An experimental study concerning the pressurization and stratification of liquid hydro-
gen, A. F. Schmidt, J. R. Purcell, W. A. Wilson, and R. V. Smith.

Temperature dependence of elastic constants of some cermet specimens, S. Spinner.

Analog simulation of zone melting, H. L. Mason.

Residual losses in a guard-ring micrometer-electrode holder for solid-disk dielectric
specimens, A. H. Scott and W. P. Harris.

A bolometer mount efficiency measurement technique, G. F. Engen.

Telescope for measurement of optic angle of mica, S. Ruthberg.

An automatic fringe counting interferometer for use in the calibration of line scales,
H. D. Cook and L. A. Marzetta.

179

Volume 64D (Radio Prop.), No. 4 (July-Aug. 1960)

Relation of turbulence theory to ionospheric forward scatter propagation experiments,

A. D. Wheelon.

Propagation at oblique incidence over cylindrical obstacles, M. P. Bachynski.
Diffraction by smooth conical obstacles, H. E. J. Neugebauer and M. P. Bachynski.
Characteristics of 488 megacycles per second radio signals reflected from the moon,

B. C. Blevis and J. H. Chapman.

Tho use of polarization fading of satellite signals to study the electron content and

irregularities in the ionosphere, C. G. Little and R. S. Lawrence.
Note on a test of the equivalence theorem for sporadic E propagation, J. W. Wright

and T. N. Gautier.
Daytime attenuation rates in the very low frequency band using atmospherics, W. L.

Taylor.
Measured electrical properties of snow and glacial ice, A. D. Watt and E. L. Maxwell.
Half- wave cylindrical antenna in a dissipative medium: current and impedance, R. King

and C. W. Harrison.
Preface to ELF papers, J. R. Wait.
Some ELF phenomena, E. T. Pierce.

Mode theory and the propagation of ELF radio waves, J. R. Wait.
Studies of natural electric and magnetic fields, G. D. Garland and T. F. Webster.
Natural electromagnetic energy below the ELF range, W. H. Campbell.
Possible application of the system loss concept at ELF, K. A. Norton.
Measurements of the spectrum of radio noise from 50 to 100 cycles per second, M. Balser

and C. A. Wagner.

Volume 64D (Radio Prop.), No. 5 (Sept.-Oct. 1960)

ELF electric fields from thunderstorms, A. D. Watt.

Field strength measurements in fresh water, G. S. Saran and G. Held.

Electrical resistivity studies on the Athabasca Glacier, Alberta, Canada, G. V. Keller
and F. C. Frischknecht.

Amplitude distribution for radio signals reflected by meteor trails, A. D. Wheelon.

Computation and measurement of the fading rate of moon-reflected UHF signals, S. J.
Fricker, R. P. Ingalls, W. C. Mason, M. L. Stone, and D. W. Swift.

On the theory of wave propagation through a concentrically stratified troposphere with
a smooth profile, H. Bremmer.

Polarization and depression-angle dependence of radar terrain return, I. Katz and
L. M. Spetner.

Methods of predicting the atmospheric bending of radio rays, B. R. Bean, G. D. Thayer,
and B. A. Cahoon.

Loss in channel capacity resulting from starting delay in meteor-burst communication.
G. R. Sugar.

Elementary considerations of the effect of multipath propagation in meteor-burst com-
munication, G. R. Sugar, R. J. Carpenter, and G. R. Ochs.

Use of logarithmic frequency spacing in ionogram analysis, G. A. M, King.

Guiding of whistlers in a homogeneous medium, R. L. Smith.

Propagation of microwaves through a magneto-plasma, and a possible method for de-
termining the electron velocity distributions, A. L. Cullen.

On electromagnetic radiation in magneto-ionic media, H. Kogelnik.

Radiation and admittance of an insulated slotted-sphere antenna surrounded by a
strongly ionized plasma sheath, J. W. Marini.

A contribution to the theory of corrugated guides, G. Piefke.

High-gain, very low side-lobe antenna with capability for beam slewing, A. C. Wilson.

Shielding of transient electromagnetic signals by a thin conducting sheet, N. R. Zitron.

Cylindrical antenna theory, R. H. Duncan and F. A. Hinchey.

Volume 64D (Radio Prop.), No. 6 (Nov.-Dec. 1960)

URSI National Committee Report:

Commission 1. Radio measurement methods and standards

Commission 2. Tropospheric radio propagation

Commission 3. Ionospheric radio propagation

Commission 4. Radio noise of terrestrial origin

Commission 5. Radio astronomy

Commission 6. Radio waves and circuits

Commission 7. Radio electronics

180

Volume 65D (Radio Prop.), No. 1 (Jan.-Feb. 1961)

Incoherent scattering by free electrons as a technique for studying the ionosphere and
exosphere: some observations and theoretical consideration, K. L. Bowles.

Radio wave absorption of several gases in the 100 to 117 kMc/s frequency range,
C. O. Britt, C. W. Tolbert, and A. W. Straiton.

On the theory of diffraction by a composite cylinder, R. D. Kodis.

An atlas of oblique-incidence ionograms (a digest), V. Agy, K. Davies, and R. Salaman.

A new approach to the mode theory of VLF propagation, J. R. Wait.

East-west effect on VLF mode transmission across the earth's magnetic field, D. Dobrott
and A. Ishimaru.

Magneto-ionic propagation phenomena in low- and very-low-radiofrequency waves re-
flected by the ionosphere, J. R. Johler.

Correlation of monthly median transmission loss and refractive index profile characteris-
tics, B. R. Bean and B. A. Cahoon.

Characteristics of waveguides for long-distance transmission, A. E. Karbowiak and
L. Solymar.

Useful radiation from an underground antenna, H. A. Wheeler.

Observation of F-layer and sporadic-E scatter at VHF in the Far East, K. Miya,
T. Sasaki, and M. Ishikawa.

A high-resolution rapid-scan antenna, H. V. Cottony and A. C. Wilson.

Volume 65D (Radio Prop.), No. 2 (Mar.-Apr. 1961)

Ionospheric motions observed with high-frequency back-scatter sounders, L. H. Tveten.

Relationship between red auroral arcs and ionospheric recombination, G. A. M. King
and F. E. Roach.

Fresnel region fields of circular aperture antennas, M. K. Hu.

Free-balloon borne meteorological refractometer, J. F. Theisen and E. E. Gossard.

Weather and reception level on a troposphere link — annual and short-term correlations,
L. G. Abraham, Jr., and J. A. Bradshaw.

Initial results of a new technique for investigating sferic activity, G. Hefley, R. H.
Doherty, and R. F. Linfield.

Effect of antenna radiation angles upon HF radio signals propagated over long dis-
tances, W. F. Utlaut.

Graphical determination of radio ray bending in an exponential atmosphere, C. F.
Pappas, L. E. Vogler, and P. L. Rice.

A formula for radio ray refraction in an exponential atmosphere, G. D. Thayer.

The impedance of a monopole antenna with a circular conducting-disk ground system
on the surface of a lossy half space, S. W. Maley and R. J. King.

Radio-wave propagation in the earth's crust, H. L. Wheeler.

Volume 65D (Radio Prop.), No. 3 (May-June 1961)

Propagation studies using direction-finding techniques, E. C. Hayden.

Diversity effects in long distance high frequency radio pulse propagation, S. A.
Bowhill.

Influence of ionospheric conditions on the accuracy of high frequency direction finding,
P. J. D. Gething.

Phase difference observations at spaced aerials and their application to direction find-
ing, W. C. Bain.

Research at the National Bureau of Standards applicable to long-distance location and
direction-finding problems, R. Silberstein.

Design for spinning goniomeier automatic direction finding, W. J. Lindsay and D. S.
Heim.

Resolution characteristics of correlation arrays, I. W. Linder.

Instrumentation for propagation and direction-finding measurements, E. C. Hayden.

Brooke variance classification system for DF bearings, E. M. L. Beale.

Estimation of variances of position lines from fixes with unknown target positions,

E. M. L. Beale.

Statistics of a radio wave diffracted by a random ionosphere, S. A. Bowhill.

Space analysis of radio signals, J. B. Smyth.

Effect of receiver bandwidth on the amplitude distribution of VLF atmospheric noise,

F. F. Fulton, Jr.

Excitation of VLF and ELF radio waves by a horizontal magnetic dipole, J. Galejs.

181

Technical News Bulletin. This monthly publication summarizes the current research,
development, and test activities of the Bureau. The articles are brief, with emphasis
on the results of research and their significance, chosen for their importance to other
scientists, engineers, and to industry. Resumes of longer research reports, important
national and international conferences on fundamental science in which the Bureau has
represented the Nation, and a bibliography of all publications by members of the staff
as published are included. The Bulletin is designed to give a succinct account of the
current work of the Bureau. (Annual subscription: domestic, $1.50; foreign, $2.25.)

Basic Radio Propagation Predictions. This is a monthly publication for those con-
cerned with radio communication in determining the best skywave frequencies over any
path at any time of day for average conditions for the month of prediction, which are
made 3 months in advance. Charts of extraordinary-wave critical frequency for the F2
layer and of maximum usable frequency for a transmission distance of 4,000 km, of
highest frequency of sporadic E in excess of 15 Mc are included. In addition, there are
various maps, charts, diagrams, and nomograms needed to make practical application of
the world-contour charts, together with examples of their use. (Annual subscription:
$1.50; foreign, $2.00.)

Monographs. These are usually contributions to the technical literature which are
too lengthy for publication in the Journal of Research. They often provide extensive
compilations of information on subjects related to the Bureau's technical program.
Until July 1959 most of this type of material was published in the Circular series.
12. Stabilization of free radicals at low temperatures. $1.50.

17. New description of thorium spectra, R. Zalubas. 65 cents.

18. Heat treatment and properties of iron and steel, T. G. Digges and S. J. Rosenberg.
35 cents.

19. Atomic energy levels in crystals, J. L. Prather. 60 cents.

20. Ideal gas thermodynamic functions and isotope exchange functions for the diatomic
hydrides, deuterides, and tritides, L. Haar, A. S. Friedman, and C. W. Beckett. $2.75.

21. Specific heats and enthalpies of technical solids at low temperatures. A compila-
tion from the literature, R. J. Corruccini and J. J. Gniewek. 20 cents.

22. Climatic charts and data of the radio refractive index for the United States and the
world, B. R. Bean, J. D. Horn, and A. M. Ozanich, Jr. $2.00.

23. Amplitude-probability distributions for atmospheric radio noise, W. Q. Crichlow,
Q. D. Spaulding, C. J. Roubique, and R. T. Disney. 20 cents.

24. A spectrophotometric atlas of the spectrum of CH from 3000 A to 5000 A, A. M.
Bass and H. P. Broida. 20 cents.

26. Development of high-temperature strain gages, J. W. Pitts and D. G. Moore. 20
cents.

27. Bibliography of temperature measurement, January 1953 to June 1960, C. Halpern
and R. J. Moffat. 15 cents.

28. Causes of variation in chemical analyses and physical tests of portland cement, B. L.
Bean and J. R. Dise. 25 cents.

29. Thermal expansion of technical solids at low temperatures. A compilation from the
literature, R. J. Corruccini and J. J. Gniewek. 20 cents.

30. Corrected optical pyrometer readings, D. E. Poland, J. W. Green, and J. L. Margrave.
55 cents.

Circulars. Circulars are compilations of information on various subjects related to
the Bureau's scientific and technical activities. They not only include the results of
Bureau studies but give data of general interest from other sources. The Circular series
was discontinued in June 1959. After this date, material that would formerly have been
published in the Circular series has been largely directed to the Journal of Research and
the new Monograph series.

510, Suppl. 2. Alphabetical index to tables of chemical kinetics. Homogeneous re-
actions. 35 cents.
539, Vol. 10. Standard X-ray diffraction powder patterns. H. E. Swanson. M. I. Cook.
E. H. Evans, and J. H. deGroot. 40 cents.

Miscellaneous Publications. As the name implies, this series includes material.
which, because of its character or because of its size, does not fit into any of the other
regular publication series. Some of these are charts, administrative pamphlets. Annual
Reports, Weights and Measures Conference Reports, and other subjects appropriate to
the Miscellaneous series.

230. Standardization activities in the United States. A descriptive directory. S. F.
Booth. $1.75.

231. Hydraulic research in the United States, 1960, H. K. Middleton. $1.00.

232. The metric system of measurement. 50 cents.

182

233. Units of weight and measure (United States customary and metric). Defini-
tions and tables of equivalents, L. V. Judson. 40 cents.

234. Household weights and measures. 5 cents.

235. Report of the 45th national conference on weights and measures, 1960. 75 cents.

236. Standard frequencies and time signals from NBS stations WWV and WWVH.
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237. Research highlights of the National Bureau of Standards, annual report 1960.
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240. Publications of the National Bureau of Standards July 1, 1957, to June 30, 1960.
(Includes titles of papers published in outside journals 1950 to 1959.) B. L. Arnold.
$2.25.

Handbooks. These are recommended codes of engineering and industrial practice,
including safety codes, developed in cooperation with the national organizations and
others concerned. In many cases the recommended requirements are given official status
through their incorporation in local ordinances by State and municipal regulatory bodies.
28. (1957) — Part III. Screw-thread standards for federal services 1957. 60 cents.

72. Measurement of neutron flux and spectra for physical and biological applications.
35 cents.

73. Protection against radiations from sealed gamma sources. 30 cents.

74. Building code requirements for reinforced masonry. 15 cents.

75. Measurement of absorbed dose of neutrons, and of mixtures of neutrons and gamma
rays. 35 cents.

76. Medical X-ray protection up to 3 million volts. 25 cents.

77. Precision measurement and calibration. Vol. I. Electricity and electronics. $6.00;
Vol. II. Heat and mechanics. $6.75; Vol. III. Optics, metrology, and radiation.
$7.00.

78. Report of the International Commission on radiological units and measurements
(ICRU) 1959. 65 cents.

Technical Note Series. This series was initiated in 1959 to supplement the Bureau's
regular publications program. Technical Notes provide a means for making available
scientific data that are of transient or limited interest. They are available by purchase
from the Office of Technical Services, U.S. Department of Commerce, Washington 25,
D.C. (Order by PB number only.)
2-2 (PB151361-2) Supplementary world maps of F2 critical frequencies and maxi

mum usable frequency factors, D. H. Zacharisen. $3.50.
18-3 (PB151377-3) Quarterly radio noise data— June, July, August 1959, W. Q. Crich

low, R. T. Disney, and M. A. Jenkins. $1.00.
18-4 (PB151377-4) Quarterly radio noise data — September, October, November 1959

W. Q. Crichlow, R. T. Disney, and M. A. Jenkins. $1.50.
18-5 (PB151377-5) Quarterly radio noise data — December, January, February 1959-60

W. Q. Crichlow, R. T. Disney, and M. A. Jenkins. $1.75.
18-6 (PB151377-6) Quarterly radio noise data— March, April, May 1960, W. Q. Crich

low, R. T. Disney, and M. A. Jenkins. $1.75.
18-7 (PB151377-7) Quarterly radio noise data— June, July, August 1960, W. Q. Crich

low, R. T. Disney, and M. A. Jenkins. $1.75.
18-8 (PB151377-8) Quarterly radio noise data — September, October, November 1960

W. Q. Crichlow, R. T. Disney, and M. A. Jenkins. $1.75.
18-9 (PB151377-9) Quarterly radio noise data — December, January, February 1960-

1961, W. Q. Crichlow, R. T. Disney, and M. A. Jenkins. $1.75.
40-3 (PB151399-3) Mean electron density variations of the quiet ionosphere, May 3,
_ 1959, J. W. Wright, L. R. Wescott, and D. J. Brown. $1.50.

55 (PB161556) Investigation of bearing creep of two forged aluminum alloys, L. Mord-
_ fin, N. Halsey, and P. J. Granum. $1.00.

59 (PB161560) Measurements and standards in plasma-physics and astrophysics at the
National Bureau of Standards. $1.00.

60 (PB161561) Amplitude and phase of the low and very low-radiofrequency ground
wave, J. R. Johler, L. C. Walters, and C. M. Lilley. 75 cents.

61 (PB161562) Proceedings of the 1960 conference on the propagation of ELF radio
waves, J. R. Wait. 75 cents.

62 (PB161563) Rapid determination of the order of chemical reactions from time-
ratio tables, J. H. Flynn. $3.00.

63 (PB 16 1564) Single scattered neutrons from an isotropic point source, E. R. Mosburg,
Jr., and W. M. Murphey. 50 cents.

64 (PB161565) Design and operation of the Coilometer computer, P. Meissner. $2.00

66 (PB161567) Radio refractometry, J. W. Herbstreit. 50 cents.

67 (PB161568) On the nature of the crystal field approximation, K. Goldberg and
C. M. Herzfeld. $2.50.

183

68 (PB161569) Transistorized building blocks for data instrumentation, J. A. Cun-
ningham and R. L. Hill. $2.00.

69 (PB 161570) Low- and very low-radiofrequency model ionosphere reflection coef-
ficients, J. R. Johler, L. C. Walters, and J. D. Harper, Jr., $2.00.

70 (PB161571) Vapor pressures of organic compounds in the range below one milli-
meter of mercury, E. E. Hughes and S. G. Lias. 75 cents.

71 (PB161572) Calibration of five gamma-emitting nuclides for emission rate, J. M. R.
Hutchinson. 75 cents.

72 (PB161573) Table of magnitude of reflection coefficient versus return loss (LB=20

logl0 _L- ) , R. W. Beatty and W. J. Anson. $1.25.

73 (PB161574) Some experiments on the deposition of gases at 4.2 °K, T. Braurer.
$1.00.

74 (PB161575) Scattering of cobalt-60 gamma radiation in air ducts, C. Eisenhauer.
75 cents.

75 (PB161576) Soviet research in field electron and ion emission, 1955-1959; an
annotated bibliography, T. W. Marton and R. Klein. $1.25.

76 (PB161577) ISOPAR. A new and improved symbolic optimizing assembly rou-
tine for the IBM 650, H. H. Howe. $1.50.

77 (PB161578) VHF and UHF power generators for RF instrumentation, A. H. Morgan
and P. A. Hudson. 75 cents.

78 (PB161579) Oblique incidence receiving antenna array for a relative ionospheric
opacity meter, A. C. Wilson. 50 cents.

79 (PB161580) VHF radio propagation data for Cedar Rapids-Sterling, Anchorage-
Barrow, and Fargo-Churchill test paths, April 1951 through June 1958, G. R. Sugar
and K. W. Sullivan. $4.00.

80 (PB161581) Bibliography of tropospheric radio wave scattering, R. L. Abbott.
$2 25

82 (PB161583) A survey of spread-F, F. N. Glover. $1.75.

83 (PB161584) On the scattering of y rays by nuclei, U. Fano. 75 cents.

84 (PB161585) Bibliography on ionospheric propagation of radio waves (1923-1960),
W. Nupen. $7.00.

85 (PB 16 1586) A survey of computer programs for chemical information searching,
E. C. Marden and H. R. Koller. $2.25.

86 (PB161587) The NBS meteor-burst propagation project — a progress report, C. E.
Hornback, L. D. Breyfogle, and G. R. Sugar. $1.25.

87 (PB161588) A theoretical study of sporadic-^1 structure in the light of radio meas-
urements, K. Tao. $1.25.

88 (PB 161589) Prolonged space-wave fadeouts in tropospheric propagation, A. P. Barsis
and M. E. Johnson. $2.00.

Publications in Outside Journals*

Achenbach, P. R., Drapeau, F. J. J., Phillips, C. W., Environmental factors in a family-
size underground fallout shelter, Proc. Natl. Acad. Sci.-Natl. Research Council
Meeting on Environmental Engineering in Protective Shelters, p. 69-118 (Feb. I960).

Achenbach, P. R., Drapeau, F. J. J., Phillips, C. W., Studies of environmental factors
in a family-size underground shelter, Report OCDM-NBS-60-1 issued by Office of
Civil and Defense Mobilization (Mar. 1961).

Agy, V., Spiral patterns in geophysics, J. Atmospheric and Terrest. Phys. 19, No. 2.
136-140 (1960).

Alexander, S. N., Trends in the technology of automatic data processing, AMA Report
41,38-42 (1960).

Allen, H. C, Jr., The structure of the vibrational-rotational bands of an asvmmetric
rotor, Phil. Trans. Roy. Soc. (London, England) [A] 253, No. 1030, 335 (1961).

Allred, C. M., Cook, C. C, A precision RF attenuation calibration system, IRE Trans.
Instrumentation 1-9, No. 2, 268-274 (Sept. 1960) .

Alt, F. L., Arithmetic, Handbook of Physics, Ed. by E. U. Condon and H. Odishaw,
Ch. 1, Pt. 1, p. 1-4-1-9 (McGraw-Hill Book Co., Inc., New York, N.Y., 1958).

Alt, F. L., Computers, Encyclopedia of Chemistry Suppl., p. 91-92 (Reinhold Publ.
Corp., New York, N.Y., 1958) .

Alt, F. L., Electronic digital computers — their use in science and engineering. Book,
Applied Mathematics and Mechanics IV, 336 (Academic Press, Inc.. New York.
N.Y., 1958).

Ambler, E., Methods of nuclear orientation, Book, Progress in Cryogenics 2, 235-280
(Hey wood and Co., Ltd., London, England, 1960).

♦For completeness, a few references to publications issued previous to July 1959 are
included.

184

Ambler, E., Some experimental aspects of nuclear orientation, Proc. Xth Intern. Con-
gress of Refrigeration, Copenhagen, Denmark, 1959, Progress in Refrigeration in
Science and Technology I, 195-198 (Pergamon Press, Inc., London, England, 1960).

Ambler, E., Dove, R. B., Continuously operating He3 refrigerator for producing tempera-
ture down to % ° K, Rev. Sci. Instr. 32, No. 6, 737-739 (June 1961).

Arms, R. J., Pipberger, H. V., Stallman, F. W., Automatic screening of normal and
abnormal electrocardiograms by means of a digital electronic computer, Proc. Soc.
Experimental Biology and Medicine 106, 130-132 (1961).

Armstrong, G. T., Marantz, S., The heat of combustion of dicyanoacetylene, J. Phys.
Chem. 64, 1776-1777 (1960) .

Arp, Y. D. Kropschot, R. H., Simple adiabatic demagnetization apparatus, Rev. Sci.
Instr. 32, 217-218 (Feb. 1961).

Arp, V. D., Kropschot, R. H., Superconducting magnetics, Proc. 1960 Cryogenic Eng.
Conf., Book, Advances in Cryogenic Engineering 6, Paper C-4, 166-173 (Plenum
Press, Inc., New York, N.Y., 1961) .

Arp, V. D., Kropschot, R. H., Wilson, J. H., Love, W. F., Phelna, R., Superconductivity
of NB3Sn in pulsed fields of 185 kilogauss, Phys. Rev. Letters 6, No 9, 452-453
(Mar. 1, 1961).

Astin, A. V., Our measurement system and national needs, Sperryscope 15, No. 6, 16-
19 (1960).

Astin, A. V., Physical measurement-challenge to science and engineering, SPE J. 17,
No. 5, 455-458 (May 1961).

Astin, A. V., The role of Government research laboratories, Elec. Engr. 78, No. 7,
738 (1959).

Ausloos, P., The effects of solvents on the gamma-ray radiolysis of methyl acetate and
acetone, J. Am. Chem. Soc, 83, No. 5, 1056-1060 (Mar. 1961) .

Ausloos, P., Murad, E., The fluorescence and phosphorescence of trifluoroacetone vapor,
J. Am. Chem. Soc. 83, 1327 (1961) .

Bailey, D. K., Ionospheric "forward" scattering, Proc. Xlllth Gen. Assembly of URSI
(London, England, 1960), Natl. Acad. Sci. -Natl. Research Council Publ. Report No.
880,281 (1961).

Bailey, D. K., Pomerantz, M. A., The cosmic ray increase of July 17, 1959, Can. J. Phys.
38, 332-333 (1960).

Ballard, D. B., Use of the bulge test for determining the mechanical properties of
stainless steel foil, Materials Research and Standards (ASTM Bull.) 1, No. 6, 471-
473 (June 1961).

Barger, R. L., Kessler, K. G., Sealed-off Hg198 atomic-beam light source, J. Opt. Soc. Am.
50, No. 7, 651-656 (July 1960) .

Barnes, J. A., Heim, L. E., A high-resolution ammonia-maser-spectrum analyzer, IRE
Trans. Instrumentation I— 10, 4-8 (June 1961) .

Barnes, J. A., Mockler, R. C, The power spectrum and its importance in precise fre-
quency measurements, IRE Trans. Instrumentation 1—9, No. 2, 194-195 (Sept. 1960).

Barnes, M. W., Noyce, R. H., Inert enclosed pump for shaped flow of ultraclean solu-
tions, Rev. Sci. Instr. 32, No. 3, 353 (Mar. 1961) .

Barone, J., Huff, R. L., Dickson, G., Surface roughness of dental gold castings,
Dental Prog. 1, No. 2, 78-84 (Jan. 1961) .

Bates, R. G., Amine buffers for pH control, Ann. N.Y. Acad. Sci. 92, 341 (1961).

Bates, R. G., Electrodes for pH measurements, J. Electroanalytical Chem. 3, 93 (1961).

Bates, R. G., Electrometric pH determination, Chimica 14, 111 (Apr. 1960).

Bates, R. G., The glass electrode, Book, Reference Electrodes, Ed. by D. J. G. Ives and
G. J. Janz, ch. 5, p. 231-269 (Academic Press, Inc., New York, N.Y., 1961).

Bates, R. G., Guggenheim, E. A., Report on the standardization of pH and related
terminology, Intern. Union Pure and Appl. Chem. 1, No. 1, 163-168 (1960).

Bates, R. G., Hetzer, H. B., Dissociation constant of the protonated acid form of 2-amino-
2-(hydroxymethyl)-l,3-propanediol [tris(hydroxymethyl) aminomethane] and related
thermodynamic quantities from 0 to 50°, J. Phys. Chem. 65, 667-671 (1961).

Bay, Z., Newman, P. A., Comparison of the ionization produced in air by alpha particles
near 5 Mev and by beta particles, Radiation Research 14, No. 5, 566-572 (May 1961).

Bay, Z., Newman, P. A., Seliger, H. H., Absolute measurement of W for Po210 alpha
particles in air, nitrogen, and carbon dioxide, Radiation Research 14, No. 5, 551-565
(May 1961).

Bay, Z., Seliger, H. H., Collection of ions produced by alpha particles in air, Phys. Rev.
120, No. 1, 141-143 (Oct. 1, 1960) .

Bean, B. R., Atmospheric bending of radio waves, Book, Electromagnetic Wave Propa-
gation, p. 163-181 (Academic Press, Inc., N.Y., 1960).

Bean, B. R., Cahoon, B. A., Limitations of radiosonde punch-card records for radio-
meteorological studies, J. Geophys. Research 66, No. 1, 328-331 (Jan. 1961).

Bean, B. R., Horn, J. D., Concerning the potential refractive index and the molecular
refractivity, J. Meteorology 18, No. 3, 427^28 (June 1961) .

616114 0^h61 13 185

Beatty, R. W., A microwave impedance meter capable of high accuracy, IRE Trans.

Microwave Theory and Tech. Letter MTT-8, No. 4, 461-^63 (July 1960).
Beatty, R. W., Engen, G. F., Anson, W. J., Measurement of reflections and losses of
waveguide joints and connectors using microwave reflectometer techniques, IRE Trans.
Instrumentation 1-9, No. 2, 219-226 (Sept. 1960).
Bechtoldt, C. J., Vacher, H. W., Redetermination of the chromium and nickel solvuses
in the chromium-nickel system, Trans. Metallurgical Soc, Am. Inst. Mining Engrs.
221, 14-18 (Feb. 1961).

Beehler, R. E., Mockler, R. C, Snider, C. S., A comparison of atomic beam frequencv
standards, Nature 187, No. 4738, 681-682 (Aug. 20, 1960) .

Bender P. L., Atomic clocks for space experiments, Astronautics, p. 69-71 (July I960).

Bennett, L. H., Budnick, J. I., magnetic resonance determination of the nuclear moment
of tantalum-181 in KTa03, Phys. Rev. 120, No. 5, 1812-1815 (Dec. 1960).

Bestul, A. B., Blackburn, D. H., Condensation coefficient of arsenic trioxide glass, J.
Chem. Phys. 33, No. 4, 1274-1275 (Oct. 1960) .

Bienenstock, A., Determination of crystallite size distribution from X-ray line broaden-
ing, J. Appl. Phys. 32, No. 2, 187-189 (Feb. 1961) .

Birmingham, B. W., Chelton, D. B., Mann, D. B., Herandez, H. P., Cryogenic engineer-
ing of hydrogen bubble chambers, ASTM Bull. No. 240, 34 (TP164) (Sept. 1959).

Blackburn, D. H., An interferometric instrument for the rapid measurement of small
diameters, Rev. Sci. Instr. 32, No. 2, 137 (Feb. 1961). .

Bloss, R. L., Evaluation of resistance strain gages at elevated temperatures, Materials
Research and Standards (ASTM Bull.) 1, No. 1, 9-15 (Jan. 1961).

Boischot, A., Lee, R. H., Warwick, J. W., Low frequency solar bursts and noise storms,
Astrophys. J. 131, No. 1, 61 (Jan. 1960).

Borkowski, R., Ausloos, P., Intramolecular rearrangements. I. Sec-butyl acetate and
sec-butyl formate, J. Am. Chem. Soc. 83, No. 5, 1053-1056 (Mar. 1961).

Bose, R. C, Connor, W. S., Analysis of fractionally replicated 2'"3" designs, Bull. Inst.
Intern. Stat. XXXVII, No. 3, 141 (1960) .

Bouche, R. R., Improved standards for the calibration of vibration pickups, Exp. Mech.
1, No. 4, 116-121 (Apr. 1961).

Bower, V. E., Paabo, M., Bates, R. G., A pH standard for blood and physiologic media.
Clin. Chem. 7, No. 3, 292 (1961).

Bower, V. E., Robinson, R. A., The ionization constants of 2-chloro-4-nitrophenol and
2-nitro-4-chlorophenol, J. Phys. Chem. 64, 1078 (1960).

Bowles, K. L., Incoherent scattering by free electrons as a technique for studying the
ionosphere and exosphere: some observations and theoretical considerations, p. 223-
243 of AGARDograph 42, The Upper Atmosphere Above F2-Maximum. North At-
lantic Treaty Organization, Advisory Group for Aeronautical Research and Develop-
ment, Avionics Panel. Papers presented at the Symp. of the Ionospheric Research
Coram., Paris, France, May 1959.

Bowles, K. L., Cohen, R. S., Equatorial region ionospheric scatter research by the NBS
during IGY, QST, p. 11-15 (Aug. 1957) .

Boyd, A. E., Morris, E. E., Spatial distribution of energy dissipated by fallout beta-
rays, Health Phvs. 2, 321-325 (Oct. 1960).

Brennan, J. A., Wilson, W. A., Radebaugh, R., Birmingham, B. W.. Testing of ball bear-
ings with five different separator materials at 9200 RPM in liquid nitrogen. Am. Soc.
Mech. Engrs. No. 61-LUBS-18, 1-8 (Apr. 10, 1961).

Brenner, A., Electrodeless passage of direct current through an electrolyte. J. Electro-
chem. Soc. 107, No. 12, 968-973 (Dec. 1960) .

Brenner, A., Electrodeposition of metals from nonaqueous media, Ch. Encyclopedia of
Chemistry and Technology 2d Suppl., p. 315-324 (Interscience Encyclopedia, New
York, N.Y., Jan. 1961).

Bretemps, F. R., Saito, S., A transistor frequency meter, Electronic Ind. 19, No. 10. 196-
198 (Oct. 1960).

Brockman, J. R., Solar disturbances and radio communication forecasts. Svk and Tele-
scope XXI, No. 6, 322-326 (June 1961) .

Broida, H. P., Golden, S., Pressure dependence of rotationally perturbed lines in the
ultraviolet band spectrum of CN, Can. J. Chem. 38, 1666-1677 (1960) .

Broida, H. P., Schiff, H. I., Sugden, T. M., Observations on the chemilumi->eseent re-
action of nitric oxide with atomic oxygen, Trans. Faraday Soc. 57, No. 458. 259-265
(Feb. 1961).

Brown, D. W., Wall, L. A., 7-irradiation of liquid and solid oxvgen. Phvs. Chem. 65.
915 (1961).

Brown, D. W., Wall, L. A., Halobenzenes as sensitizers for the radiation induced poly-
merization of styrene, J. Polymer Sci. 44, 325-340 (June 1960) .

Brown, E. H., On the properties of the vapor pressure curve. Cryogenics 1, No. 1. 37-40
(Sept. 1960).

186

Budnick, J. I., Bennett, L. H., Nuclear magnetic resonance in tantalum metal, J. Phys.

Chem. Solids 16, No. %, 37-38 (Jan. 12, 1960) .
Bussey, H. E., Cavity resonator dielectric measurements of rod samples, Conf. Electrical

Insulation (Annual Report of 1959), Natl. Acad. Sci.-Natl. Research Council Publ.

756, 15 (1960).
Bussey, H. E., Standards and measurements of microwave surface impedance, skin depth,

conductivity and Q, IRE Trans. Instrumentation 1—9, No. 2, 171-175 (Sept. 1960).
Cameron, J. M., Digital techniques in statistical analysis of experiments, Handbook of

Automation, Computation, and Control, Ed. By E. M. Grabbe, S. Ramo, D. E. Wool-
ridge, Ch. 14, Sec. 4, p. 14-48-14-55 (John Wiley & Sons, Inc., New York, N.Y., 1958).
Campbell, W. H., Leinbach, H., Ionospheric absorption at times of auroral and magnetic

pulsations, J. Geophys. Research 66, No. 1, 25-34 (Jan. 1961).
Campbell, W. H., Rees, M. H., A study of auroral coruseations, J. Geophys. Research

66, No. 1,41-55 (Jan. 1961).
Carpenter, F. G., Deitz, V. R., A study of the chemical reactions in kilning bone char,

Proc. 6th Tech. Session on Bone Char 1959, p. 321 (Bone Char Research Project Inc.,

Charlestown, Mass., 1961).
Carpenter, R. J., Beaty, E. C, Bender, P. L., Saito, S., Stone, R. 0., A prototype rubidium

vapor frequency standard, IRE Trans. Instrumentation 1—9, No. 2, 132-135 (Sept.
^ 1960) .
Caswell, R. S., Neutron-insensitive proportional counter for gamma-ray dosimetry, Rev.

Sci. Instr. 31, No. 8, 869-871 (Aug. 1960) .
Caul, H. J., Clabaugh, W. S., Susa, M. E., Procedure for the determination of the noble

metal content of dental gold alloys, J. Am. Dental Assoc. 61, No. 4, 439-443 (Oct.

1960).
Cavallo, L. M., The organization of international intercomparisons of radioactivity

standards, with special reference to such measurements of NBS standards, Proc.

Symp. Metrology of Radionuclides, IAEA, Vienna, Austria, p. 117 (JL960).
Chadwick, W. B., Improvements in radio propagation prediction service, Elec. Engr. 79,

No. 9, 721 (Sept. 1960).
Chamberlain, J. W., Hunten, D. M., Rundle, H. N., Resonance scattering by atmospheric

sodium VII. Measurement of the vertical distribution in twilight, J. Atmospheric and

Terrest. Phys. 17, 205-219 (1960).
Chapman, S., Geomagnetic storms and the space around the earth, Nature 187, No. 4740,

824-827 (Sept. 3, 1960).
Chelton, D. B., Dean, J. W., Birmingham, B. W., Closed circuit liquid hydrogen re-
frigeration system, Rev. Sci. Instr. 31, 712-716 (July 1960).
Chilton, C.j VLF phase perturbations associated with meteor show ionization, J. Geophys.

Research 66, No. 2, 379-383 (Feb. 1961) .
Chivers, H. J. A., Observed variations in the amplitude scintillations of the Cassiopeia

(23N5A) radio source, J. Atmospheric and Terrest. Phys. 19, 54 (Sept. 1960).
Chivers, H. J. A., The simultaneous observation of radio star scintillations on different

radio-frequencies, J. Atmospheric and Terrest. Phys. 17, No. 3, 181-187 (1960).
Clabaugh, W. S., Reagent chemicals, Specifications prepared by the Committee on

Analytical Reagents, Am. Chem. Soc. (1961).
Cleek, G. W., Scuderi, T. G., Evaluation of some oxide glasses for use as infrared ma-
terials, Proc. Infrared Information Symp. 5, 4 (Aug. 1960) .
Cohen, R. S., Bowles, K. L., On the nature of equatorial spread F, J. Geophys. Re-
search 66, No. 4, 1081-1106 (Apr. 1961) .
Comeford, J., Gould, J., Infrared spectra of solid hydrocarbons at very low temperatures,

J. Mol. Spectroscopy 5, 474 (1960).
Connor, J. H., Lamb, V. A., Deposition of iron from salts of fluoro-acids, Plating 48, No.

4, 388-389 (Apr. 1961).
Conrad, G. T., Jr., Newman, N., Stansbury, A. P., A recommended standard resistor-noise

test system, IRE Trans. Component Parts CP-7, No. 3, 71-88 (Sept. 1960).
Cooper, J. W., Calculations of the neutron age in water and heavy water for D-D

sources, Nuclear Sci. and Eng. 10, No. 1, 1-10 (May 1961) .
Cooper, J. W., The oscillator strength distribution of rare gas atoms calculated in a

central potential model, 2d Intern. Conf. Physics of Electronic and Atomic Collisions,

p. 7-10 (University of Colorado, Boulder, Colo., June 12-15, 1961) .
Corliss, C. H., Meggers, W. F., Scribner, B. F., Residual arc spectra of seventy elements

diluted in copper, Book, Colloquium Spectroscopicum Internationale VIII, 119-121

(1960).
Corruccini, R. J., Interpolation of platinum resistance thermometers, 20° to 273.15°K,

Rev. Sci. Instr. 31, 637-640 (June 1960).
Corruccini, R. J., Johnson, V. J., Mcintosh, G. E., Scott, R. B., Cryogenics, ASRE Data

Book, Refrigeration Applications, Ed. by V. J. Johnson, 1, No. 1, Ch. 45, 45-01-45-22

(Am Soc. Refrig. Engrs., New York, N.Y., 1959) .

187

Crow, E. L., An analysis of the accumulated error in a hierarchy of calibrations, IRE

Trans. Instrumentation 1-9, No. 2, 105-114 (Sept. 1960).
Culshaw, W., Resonators for millimeter and submillimeter wavelengths, IRE Trans.

Microwave Theory and Tech. MTT-9, No. 2, 135-144 (Mar. 1961).
Curtis, A. J., Dielectric properties of polyamides, J. Chem. Phys. 34, No. 5, 1849-1850

(May 1961).
Cutkosky, R. D., Shields, J. Q., The precision measurement of transformer ratios, IRE

Trans. Instrumentation 1-9, No. 2, 243-250 (Sept. 1960) .
Dahl, S., Kaplan, A. M., 4-nitrophenyl esters, carbonates, and bis-carbonates as leathei

fungicides, J. Am. Leather Chemists Assoc. 55, 480 (Sept. 1960) .
Dannemiller, M. C, Zelen, M., Robustness of life testing procedures based on the ex-
ponential distribution, Technometrics 3, No. 1, 29-^49 (Feb. 1961) ; Missile Design and

Development, p. 35-36 (Mar. 1961).
Davies, K., A study of 2-Mc/s ionospheric absorption measurements at high latitudes, J.

Geophys. Research 65, No. 8, 2285-2294 (Aug. 1960) .
Davis, M. M., Paabo, M., Acid-base equilibria in benzene at three temperatures. The

comparative reactivities of a phenolic acid and a carboxylic acid with triethylamine

and with 1,3-diphenylguanidine, J. Am. Chem. Soc. 82, 5081-5084 (1960).
Davis, P., Rabinowitz, P., Some SEAC computations of subsonic flows, Book, Bergman's

Linear Integral Operator Method in the Theory of Compressible Fluid Flow, by M. Z.

Krzywoblocki, p. 148-172 (Wien, Springer- Verlag, Berlin, Germany, 1960).
Deitz, V. R., Survey of variations in use for conducting laboratory-scale column Alteration

tests, Proc. 56th Tech. Session on Bone Char 1957, p. 237 (Bone Char Research

Project Inc., Charlestown, Mass., 1959) .
Dibeler, V. H., Reese, R. M., Franklin, J. L., Mass spectrometric study of cyanogen and

cyanoacetylenes, J. Am. Chem. Soc. 83, 1813-1818 (1961) .
Digges, T. G., Research on light metals in the Metallurgy Division, NBS, India Tech. J.

(Natl. Metals Lab., Jamshedpur, India) , III, No. 1, 22 (Feb. 1961) .
Douglas, T. B., Current thermodynamic research on light-element compounds at the

National Bureau of Standards, Proc. Propellant Thermodynamics and Handling

Conf., Spec. Rept. 12 (Ohio State University, Columbus, Ohio, June 1960).
Dressier, K., Schnepp, O., Absorption spectra of solid methane, ammonia, and ice in

the vacuum ultraviolet, J. Chem. Phys. 33, No. 1, 270-274 (July 1960).
Dunfee, B. L., A standard current transformer and comparison method — A basis for the

establishing ratios of currents at audio frequencies, IRE Trans. Instrumentation 1—9,

No. 2, 231-236 (Sept. 1960).
Edlow, M. H., Plumb, H. H., Reproducibilities of carbon and germanium ther-
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203

PATENTS

The following U.S. patents have been granted to NBS inventors; assigned (or
licensed as indicated) to the United States of America, as represented by the Secretary
of the department noted in parentheses :

Ambler, Ernest, No. 2,982,106, May 2, 1961. Low temperature refrigeration apparatus
and process. (Commerce.)

Bryan, Ray K., No. 2,945,922, July 19, 1960. Micro-adjustable switch. (Licensed to
the United States of America as represented by the Secretary of Commerce.)

Corliss, Edith L. R., Burkhard, Mahlon D., and Koidan, Walter, No. 2,968,695, Jan-
uary 17, 1961. System for monitoring and controlling the motion of a sound source.
(Commerce.)

Harris, William P., and Cooter, Irvin L., No. 2,960,652, November 15, 1960. Bridge
method for the measurement of core losses in ferro-magnetic material at high flux

Hoffman, John R., and Carlson, Robert E., No. 2,962,706, November 29, 1960. Aerial
Navigation aid. (Licensed to the United States of America as represented by the
Secretary of Commerce.)

Hogue, Ephraim W., No. 2,946,046, July 19, 1960. Magnetic digital computer circuit.
( Commerce. )

Lesti, Arnold, and Baechtel, Andrew R., No. 2,945,220, July 12, 1960. Analogue-digital
converter. ( Commerce. )

Minor, Irene C, and Bennett, John A., No. 2,984,101, May 16, 1961. Tape method for
detecting fatigue cracks. (Commerce.)

Parkhurst, Douglas L., No. 2,955,467, October 11, 1960. Pressure-type tide recorder.
(Licensed to the United States of America as represented by the Secretary of Com-
merce. )

Perls, Thomas A., and Kissinger, Charles W., No. 2,958,216, November 1, 1960.
Resonant-beam calibrator. (Commerce.)

Plitt, Karl F., No. 2,985,609, May 23, 1961. Aqueous pressure-sensitive adhesive com-
position comprising polyvinylalcohol and a polyethylene amine, and method of making.
( Commerce. )

Pummer, Walter J., Wall, Leo A., and Florin, Roland E., No. 2,967,894, January 10,
1961. Method for the preparation of aromatic fluorocarbons. (Army.)

Rabinow, Jacob, No. 2,961,093, November 22, 1960. Conveyor belt sorters. (Com-
merce. )

Reaves, John H., No. 2,955,246, October 4, 1960. Low capacitance power supply.
(Commerce.)

Reaves, John H., No. 2,970,278, January 31, 1961. Direct-coupled amplifier construction.
(Commerce.)

Reaves, John H., No. 2,978,658, April 4, 1961. Low capacitance power supply.
(Commerce.)

Sargent, Jack, and Birnbaum, George, No. 2,964,703, December 13, 1960. Recording
microwave hygrometer. (Commerce.)

Slutz, Ralph J., No. 2,953,774, September 20, 1960. Magnetic core memory having
magetic core selection gates. (Commerce.)

Thompson, Moody C, Jr., Freethey, Frank E., and Waters, Donald M., No. 2,981,908.
April 25, 1961. Cavity resonator. (Commerce.)

Weaver, Elmer R, No. 2,966,864, January 3, 1961. Refrigerator lock with inside
release. ( Commerce. )

204

U.S. GOVERNMENT PRINTING OFFICE: 1961 O 616114

REPORTING . . . NBS Re§earch and Development

if Journal of Research of the National Bureau of Standards contains full research papers,

inoluding laboratory data, experimental procedures, and theoretical and mathematical
analyses. Advances in measurement standards and techniques , , , physical constants
» • i properties of materials , , , instrumentation . . , radio propagation.
The Journal is published in four separate sections , , ,

A, Fhysles and Chemistry=i8sued six times a year; Annual subscriptions Demestie,

14,00; Foreign, $4,75,

1, Mathematies and Mathematieal Physies^issued quarterly | Annual subscriptions
Demestie, $2,25: Foreign, $2,75.

€!, Engineering and Instrumentatien=is8ued quarterly; Annual subseriptiens Do-
mestic, $2,25; Foreign, $2.75,

B, Radio Prepagatien=is8ued six times a year; Annual subseriptienj Demestie,

$4,00; Foreign, $4,7§\

if National Bureau e! Standards Tiehnteal News M/el^—lllustrated concise articles
ea NBS programs in the physieal seienees, with emphasis en results ef researeh, are
ehesen en the basis ef their seientifle and technological impertanee, The Teehnleal
Nm$ Bulletin reports advanees in measurement standards and teehniques, the latest
information on NBS calibration serviees and Standard Materials, and announees aU
publications and patents of staff members, Speeial events and teehnieal meetinp
involving the Bureau are summarised,

Issued monthly,

Annual subseriptiens Demestie, $1,50; Foreign, $2.25,

BORDER FROM Superintendent of Documents, U.S. Government Printing Office,

Washington 25, D.C.

U. S. DEPARTMENT OF COMMERCE

PENN STATE UNIVERSITY LIBRARIES

ADD0D7nilH3

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