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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 

iv 



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 



VI 



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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in 2012 with funding from 

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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 (Nb 3 Sn) 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. 



8 



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. 

10 



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13 



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 

14 



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 

15 



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. 



16 



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. 

17 



"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. 

18 




:"<..*:' 



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. 



19 



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- 

20 



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). 

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 10 6 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. 

22 



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. 

23 




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- 

24 



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- 

26 




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- 



27 



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 

28 



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 

29 




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 

30 



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 

31 



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). 



32 



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. 

33 




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. 

34 



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. 



35 



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. 

36 



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/m 2 and 140 amp/m 2 , 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). 



37 



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 Cu 2 0, CoO, and Mn 3 4 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 

38 




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 Ni 61 was observed in 
99.97 percent pure nickel metal. It was found that the resonance occurs 

39 



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 Ni 61 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. 

40 




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- 



41 



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 10 10 . 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. 

42 



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). 

43 



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 10 11 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 

44 



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 10 10 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 10 11 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 

45 




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. 

46 



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- 

47 



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. 

48 




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 



49 



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 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. 

50 



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 

51 



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). 

52 



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- 

53 




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. 



54 



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/cm 3 may be sufficient, as 
compared to the 10~ 2 hydrogen atoms/cm 3 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. 

55 



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- 

56 



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 10 s to 10 3 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 

58 




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 

59 



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 

60 



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 C 2 H 2 were very accurately estab- 
lished. Similar studies on the deuterated acetylenes, C 2 HD and C 2 D 2 , 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 (Ti0 2 ), has a large, low-frequency 
dielectric constant (e c = 173 and e a — ^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). 

61 



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 ^lO 11 particles/cm 3 , 
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 

62 




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. 



63 



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 

64 






"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. 

65 



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 

66 



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 

67 




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. 

68 



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 10 8 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 Co 60 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 10 7 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. 

69 



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 Ca 40 and C 12 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 Co 60 is contained in the 
vertical metal tubes at the center (page 69). 

70 



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. 

71 



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 

72 




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. 

73 



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. 

74 



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 C 7 and C 8 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- 

75 



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). 



76 



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. 

77 



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 

78 




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 

79 



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 


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 CF 2 molecule, which is an im- 

80 



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 CF 2 
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 NF 2 radical was initiated. By measurement and 
analysis of the infrared spectrum of NF 2 , 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). 



81 



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 U 235 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 U 234 . 

A special mass spectrometer was developed for analyzing uranium hexa- 
fluoride and is being used to evaluate standards having low concentrations 
of U 235 . 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 

82 




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 

83 



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 (A1 2 3 ) and rutile (Ti0 2 ) with much 
greater control over purity and perfection. 

84 



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). 

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. 

86 




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. 

87 



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 the T study 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 

88 



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 D 2 for H 2 as the solvent in sulfuric acid solution raises 
the glass transformation temperature 2.6 °C, from —129.5 to —126.9 °C. 
For partial D 2 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). 

90 



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- 

91 



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. 

92 



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'b 3 Sn) 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 Nb 3 Sn 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 Nb 3 Sn 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- 

93 



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). 



94 



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 

95 




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 



96 



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 

97 



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. 

98 




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 

99 



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 



y 



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 2 m S n 
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 X 2 -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 10 4 . 

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 y 50 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 







"**^ud t ^~- 



\ V 




Ag*3* 



> 



* ■ / - 



IMHHBHK ' V':'' SBHHaHH 

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 Nb 3 Sn, 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 and 100 °F; and the relative 
humidity controlled between 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 ft 2 /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 

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 

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 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 & SVCSJj 4 ! £1^8 137£ 1776 ^£^1^^ 1284 1262 ^° 283 296 3 1 3 









r""" 


\ 
\ 


















OTHER FUNDS 


/ 
/ 
/ 




\ 
\ 
\ 




















* 


t 




\ 


















^,- 


' 






















































* "^ """ — •. 





■ NBS APPROP. 































..-.1.— 

CALIB. a svcs. 

1 



TOTAL 



1853 2223 2442 2672 3578 3734 2402 1939 1994 2038 2122 2185 2298 243 3 



so 




• 








n OBLIGATIONS 
















40 








/ 
/ 
/ 


"**>* 

* 


i 




• 




















/ 
/ 
/ 
f 




\ 
























OTHER FUNDS 




\ 




















30 




/ 
























20 






/ 
/ 
/ 

1 

1 






\ 
\ 
\ 
\ 
\ 
















10 






1 
i 
1 

> 






< 




.. 




> ^-*"' 







OTHER 


R&D 














































N BS APPROP. 













1 


















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 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 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 B 3 N 3 H 6 , 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 AB 4 B , 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. 
10 cents. 

237. Research highlights of the National Bureau of Standards, annual report 1960. 
65 cents. 

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 (L B =20 

l ogl0 _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 He 3 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 NB 3 Sn 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 Hg 198 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). 

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201 



Wait, J. R., On the theory of the slow-tail portion of atmospheric waveforms, J. Geophys. 

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Wall, L. A., Polymer decomposition: thermodynamics, mechanisms, and energetics, 

SPE J. 16, Pt. I, 810-814 (Aug. 1960); 16, Pt. II, 1031-1035 (Sept. 1960). 
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tetrakis-(pentafluorophenyl)-silane and tris-(pentafluorophenyl)-phosphine, J. Am. 

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Wallenstein, M. B., Krauss, M., Interpretation of the appearance potentials of second- 
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Warwick, J. W., Lawrence, R. S., The use of interferometer observations of satellites 

for measurement of irregular ionospheric refraction, Ann. IGY XII, Pt. 2, 566-569 

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Warwick, C. S., McDonald, N., Pohrte, T., A search for geomagnetic singular days, 

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Weldon, J. M., Shapley, A. H., Lincoln, J. V., Plan for seophvsical alerts and special 

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West, E. D., Techniques in calorimetry. I. A noble-metal thermocouple for differential 

use, Rev. Sci. Instr. 31, No. 8, 896-897 (Aug. 1960). 
Wexler, A., Humidity standards, TAPPI 44, No. 6, 180a (June 1961). 
Wiese, W. L., Mechanical spectrograph shutter for extremely short exposure times. 

Rev. Sci. Instr. 31, 943 (1960). 
Wiese, W. L., Berg, H. F., Griem, H. R., Measurements of temperatures and densities 

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Wiese, W. L., Berg, H. F., Griem, H. R., Measurement of the structure of strong shocks 

in helium-filled T tubes, Phys. of Fluids 4, 250 ( 1961 ) . 
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IRE Trans. Ant. Prop. AP-8, No. 2, 144-157 (Mar. 1960) . 
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bearing separator materials operating submerged in liquid nitrogen, ASLE-ASME 

202 



Lubrication Conf., Oct. 17-19, 1960 (Boston, Mass.), Am. Soc. Lubrication Engrs. 

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Wilson, W. K., Mandel, J., Determination of carboxyl in cellulose — comparison of 

various methods — TAPPI — ACS-ASTM-ICCA subcommittee on determination of car- 
boxyl, TAPPI 44, No. 2, 131 (1961). 
Wilson, W. K., Mandel, J., Determination of pentosans. Interlaboratory comparison of 

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(Dec. 1960). 
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1935 (1961). 

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, 



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