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1963

RESEARCH HIGHLIGHTS

V.:- v \ "i',: OF THE

ATIONAL BUREAU OF STANDARDS

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NNUAL REPORT
The groups to be served by the specialized services of the National

Bureau of Standards were well defined by the Congress at the time

the Bureau was founded. The Committee on Coinage, Weights and

Measures in recommending to the House of Representatives in May

of 1900 that a National Bureau of Standards be established, said

"It is therefore the unanimous opinion of your committee that no more

essential aid could be given to manufacturing, commerce, the makers of

scientific apparatus, the scientific work of the Government, of schools,

colleges and universities, than by the establishment of the institution proposed in this bill."

This statement, which provides an enduring focus for the activities of

the Bureau, will be engraved in stone in the lobby of the Administration Building at the new laboratory site near Gaithersburg, Maryland.

A. V. Astin, Director,

National Bureau of Standards.
UNITED STATES DEPARTMENT OF COMMERCE

Luther H. Hodges, Secretary

J. Herbert Hollomon, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

1963

Research Highlights

of the

National Bureau of Standards

Annual Report, Fiscal Year 1963

December 1963

Miscellaneous Publication 255

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C., 20402 - Price $1.00
Library of Congress Catalog Card Number: 6-23979
Contents

Page

1. General review 1 Basic measurement standards 2 Standard reference data 7 National Standard Reference Data System 8

Engineering measurement standards 9

Standard reference materials . 11

Special central missions 14

Radio propagation 14

Data-processing systems 15

Building research 15

Consulting services 15

Background research 18

Internal support activities 19

International activities 19

Administrative activities 21

Publications and technical information 24

2. Highlights of the research program 26

2.1. Physics, electronics, and measurement standards 26

2.1.1. Metrology 26

A new standard of spectral irradiance 27

Basis for color measurement amended 27

Calibration of fiashtubes 28

Fluorescent lamp measurements intercompared 28

Equipment developed for calibrating thermal detectors 28

Equipment developed for densitometric calibrations 29

Refractive index of calcium fluoride 30

Generalized lens-bending procedure developed 30

Technique for deriving principal curvatures of wave fronts ... 30

Image evaluation 31

Measurement of wave fronts 31

Stored microfilms inspected 31

Microcopy chart designed 31

Method developed for measuring thiosulfate in processed film. . 32

Length measurement research 32

Thermal expansion measurement capability extended 32

Wave-front-shearing interferometer 32

Screw thread standardization 33

Laser produces fringes over 200-meter path 33

Cockpit lighting in TFX aircraft 33

Accuracy of spectral transmittance standards investigated. . . 33

Goniophotometry 34

2.1.2. Mechanics 34

Vibration amplitudes measured . 35

Microphone calibration 35

Portable tube designed for sound-absorption measurements. ... 35

Cavitation data obtained 36

Measurement of impact sound transmission in buildings 36

Infrasonic waves studied in the atmosphere and in the earth ... 36

Audiometry research 38

Improvements sought in pressure and vacuum measurements . . 38

Computer techniques applied in turbulence studies 39

Boundary layer instability and effect of roughness 39

Standards designed for million-pound forces 40

Compact precision centrifuge constructed 41

Rheological constitutive equations 41

Review of volume relaxations in polymers 41

Hypersonic combustion 42

Reference fuel control test facilities operated at the Bureau. ... 42

Sla tic electric failure of aircraft engine fuel hose 43

Reference tables for a new thermocouple to be established. ... 43

Flame speed inhibitors 44

High-temperature thermocouples 44

III
2. Highlights of the research program—Continued

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

2.1.3. Electricity 44

Absolute measurements 44

Impedance of dry cells 45

Battery depolarizers at high temperatures 46

Zener diodes as voltage standards 46

Membrane potentials in fused salts 46

Differential a-c-d-c transfer standard 47

Magnetism 47

Dielectric behavior of liquids and supercooled liquids at ele- vated pressures 48

Precision measurement of the dielectric constant of solid bodies. 49

Humidity-time studies of dielectric constant and loss index. ... 49

Theoretical studies on dielectrics 50

Chain-folding in polymer crystals 50

Dielectric properties of polymers 50

Dielectric properties of dipolar chain compounds 50

Microwave absorption in compressed gases 51

High voltage 52

2.1.4. Radio standards 52

Theoretical physics 53

Radio standards physics 53

Fort Collins standard radio transmitting site 53

Atomic frequency standard research 54

Quantum electronics 55

Radio and microwave materials 56

Magnetics 56

Dielectrics 57

Conductivity 57

Materials synthesis 57

Plasma 57

Microwave interactions with plasma 58

Speed of light (diffraction correction) 58

Stark voltmeter 59

Radio standards engineering .• . 59

Low-frequency calibration 59

High-frequency standards and calibration 60

Microwave standards and calibration 62

Fabry-Periot interferometer used as a dilatometer 64

2.1.5. Heat 65

Molecular energy levels program 65

Plasma transport processes 66

Automatic thermocouple comparator 66

Thermodynamic properties of light-element compounds 67

Computer analysis of low-temperature heat-capacity data. ... 68

Thermal diffusivity standards 69

Microwave spectroscopy 69

Nuclear orientation 69

Shock wave reaction kinetics 69

Thermodynamic properties of gases at high temperature 70

2.1.6. Atomic physics 71

Continuum states in rare gases 71 Plasma and astrophysics 74

Atomic energy levels 74

Wavelength standards 75

Infrared spectroscopy of gases 75

Shapes of rotational lines as influenced by pressure 76

Absorption spectra of solids 76

Solid state physics 76

Electron optics 77

Measuring velocity of light 77

Optical pumping 77

Magnetic moment of the proton 78

Experimental atomic collisions 78

2.1.7. Radiation physics 78

X-ray and gamma-ray dosimetry 79

Cavity chambers 79

Photographic dosimetry 79

Solid state dosimetry 79

IV
Highlights of the research program-—Continued

2.1. Physics, electronics, and measurement standards—Continued

2.1.7. Radiation physics—Continued

Response of silicon charged particle detectors at low temper- Page

atures 80

Radioactive sources 80

Scattered spectrum of water-shielded sources 80

Standards of radioactivity 80

Radiation interaction with matter 82

Radiation interaction with nuclei 82

The interaction of bremsstrahlung with alined nuclei 82

Nuclear matter distributions as determined from neutral meson photoproduction 82

Neutron time-of-flight techniques . 84

Particle interaction theory 85

Preparations for new linear accelerator 85

Linear accelerator theory 85

Heavy-ion source for magnet-optic studies 86

High-current beam-handling problems 86

Equipment for use with Linac 86

Data-logging and data-handling system for the linear

accelerator 86

2.1.8. Laboratory astrophysics 87

Physics of atomic collisions 88

Astrophysics 89

Resonance physics 89

Plasma physics, statistical physics, and aerodynamics 90

Data center on atomic collision cross sections 90

2.2. Chemistry and properties of materials 90

2.2.1. Analytical and inorganic chemistry 90

Atomic weight redetermination 91

Reactivity of coordination compounds 91

Thermodynamics of aqueous solutions 91

pH scale for alcohol-water solvents 91

Dielectric cryometry for determining purity 92

Argon shielding in spectrochemical analysis 92

Transition probabilities 93

Laser microprobe 93

Solvent effects on the rates of acid-catalyzed reactions 94

Acidities of dinitrophenols in benzene and water 94

Crystal growth from mixed solvents 94

Studies of crystal symmetry 95

X-ray analysis of crystalline solids 95

Control of fractional distillation 96

Moisture determination 96

2.2.2. Physical chemistry 96

Thermochemistry 97

Kinetics of ion decomposition 97

Field emission / 97

High-temperature microwave spectroscopy 97

Enolization and isomerization reactions of reducing sugars ... 98

Cryogenic surface chemistry 99

Kinetic isotope effects 99

Shock-wave studies of unimolecular reactions 99

Ionization processes at surfaces 100

Polycyclic ketones 100

Vacuum ultraviolet photochemistry 101

High-temperature surface reactions 101

Radiolysis of simple hydrocarbons ; 101

Standard reference data in physical chemistry 102

2.2.3. Inorganic solids 102

Rare gas crystals 102

Molar volume of solid neon isotopes 103

Crystalline forms of bismuth oxide 103

Random network models for liquid and glass studies 104

Vapor-pressure studies 105

Crystal structure determinations 105

Phase change studies of silica-metal oxide systems 105

Standard glasses for viscosity measurements 106

Elastic constant data 106

V
2. Highlights of the research program—Continued

2.2. Chemistry and properties of materials—Continued

2.2.3. Inorganic solids—Continued Page

Structural studies of materials under high pressures 106

Mechanical properties of ceramic bodies 108

2.2.4. Metallurgy 108

Metal fatigue investigated in aluminum alloys 109

Properties of metals at elevated temperatures 109

Gage block materials demonstrate desired stability 110

Deformation of metals studied at low temperatures 110

Slack-quenching technique developed 110

Stress corrosion of carbon steels Ill

Effect of applied current on aluminum corrosion Ill

Corrosion reactions studied at metal surfaces Ill

Pure alloys prepared Ill

Standard samples Ill

Equilibrium diagrams developed 112

Experimental alloy demonstrates usefulness 112

Steel pilings inspected 112

Correlation effects for impurity diffusion 112

Electron microanalysis provides basic data 112

Quantitative metallography derived with computer 112

Anisotropic effects studied in a cubic alloy 113

X-ray diffraction employed for crystal structure studies. ... 113

Dislocations in metals investigated 113

Kinetics of whisker growth and evaporation. . . 113

Properties of electrodeposited copper 114

Electrocrystallization investigated 115

Calorimetry used to study fused salts 115

Peltier effect measured at liquid junctions 115

Cooperative services provided 115

2.2.5. Polymers 116

Ethylene-propylene copolymers analyzed 116

Bitumen content in expansion joint fillers readily determined. . 117

Tensile properties of paper 117

Tongue-tear methods for woven fabrics evaluated 117

Color tests devised for antioxidants in synthetic rubbers 118

Point-projection X-ray microscopy used to study polymers. ... 118

Leather macroporous structure investigated 119

Structural transformations observed in polymers at high pres- sures 119

Phase equilibria in polymer solutions 119

Statistical calculations made of polymer properties 120

Rubber crystallization investigated 120

Failure phenomena of fibers studied at high impact velocities . . 120

Radiation-induced polymerization under high pressure 122

Fluoroaromatic polymers prepared 123

High-energy radiation effects on polymers 123

Thermal stability of coordination polymers investigated 124

Stereoregular polyacenaphthylene produced 124

Polymer adsorption 124

Molecular weight standards for polystyrene 124

Structure and strength of teeth 125

X-ray spectrometer used for analysis of dental alloys 125

Dental cements 126

2.3. Special technical service programs 126

2.3.1. Applied mathematics 126

Numerical analysis 126

Asymptotic expansions 127

Quadrature and interpolation 127

Linear algebra and matrix theory 127

Machine translation 127

Mathematical tables 128

Digital computations 128

Statistical engineering 128

Research and development 129

Experiment design and consultation 129

Mathematical physics 130

Plasma research 130

Theory of satellite orbits 130

VI
Highlights of the research program—Continued

2.3. Special technical service programs—Continued

2.3.1. Applied mathematics—Continued Page

Operations research 130

New computer facilities at Boulder Laboratories 131

Mathematics group at Boulder Laboratories 131

Statistical studies at Boulder Laboratories 131

2.3.2. Data-processing systems 132

Research information center 132

Components and techniques 133

. Scientific information processing 134

Technical assistance for data processing 135

Information-processing systems 136

Engineering applications and devices . . 138

Special studies and analyses 138

Management data processing 140

Automatic mail-sorting developments 140

2.3.3. Instrumentation 141

Failure anticipation by semi-automatic techniques 141

Hall effect measurements 142

Vacuum physics 142

A photoelectric ratio-measuring system for incident light 143

Proportional temperature controllers 143

Hygrometry 144

Electromechanical transducers 145

Instrument reference service 145

2.3.4. Radio propagation 146

IQSY 146

Ionosphere research and propagation 146

Geomagnetic micropulsations and infrasonic pressure waves . 146

Lunar tide effect in the D-region 147

Effect of VLF propagation on standard frequency trans- missions 147

Ionizing processes in the D-region of the ionosphere 148

Ionospheric predictions by numerical mapping 148

First topside sounder satellite 149

Planetary ionosphere 150

Assistance to Project Mercury 150

Ionospheric ray tracing 151

Operation Fish Bowl 151

Thermal properties of the F-region 152

Chemical release in the ionosphere 152

Electron density measurements in the ionosphere 153

Troposphere and space telecommunications 153

Reports to the CCIR , 153

Prediction methods 154

Electromagnetic theory 154

Point-to-point moon communication 154

Radio meteorology 154

Efficient television assignments 155

UHF air-ground propagation tests 155

Refractive effects in microwave distance and position

measurement systems 156

Surface-satellite communication interference 156

Bandwidth of the tropospheric propagation medium 156

Radio noise predictions 158

Floating noise recordings 158

Automatic data analysis facility 159

Radio systems 159

High-frequency ionospheric radar research

.

159

Solar flares 161

Modulation research 161

Digital errors 162

Testing facsimile equipment 162

Recording atmospheric noise 162

Multipath microwave transmission 163

Antenna measurements and research 163

Computer program for radiation patterns 163

Frequency utilization 164

Radio navigation research—low-frequency Loran 165

VII
2. Highlights of the research program—Continued

Special technical service programs—Continued

2. 3. 4. Radio propagation—Continued

Radio Systems—Continued

Applied electromagnetic theory at frequencies below 300 Page

kc/s • 166

Optical communication studies 167

Upper atmosphere and space physics 167

Jicamarca Radar Observatory 167

Digital control and correlation system for the Jicamarca

Radar Observatory 169

Studies at magnetically conjugate points 170

Continuous observations of VLF emissions 170

VLF emissions and whistlers at conjugate points 170

Electron densities in the lower ionosphere 171

Auroral absorption 171

Absolute calibration of airglow photometers 172

Mid-latitude red arcs 172

Studies of ionospheric irregularities 172

Theoretical studies of the outermost atmosphere 173

Cyclotron resonance in slightly ionized gases 174

Space resolved afterglows 174

Infrared spectra of charge transfer complexes 174

Infrared spectroscopy of the atmosphere 175

Electromagnetic research 175

Resonant characteristics of a corrugated sphere 175

Influence of a sector ground screen on the field of a vertical antenna 176

The theory of an antenna over an inhomogeneous ground

plane 176

Curves for groundwave propagation over mixed land and

sea paths 176

Wave propagation around a curved boundary containing an obstacle 176

Oblique propagation of radio waves across a coastline 176

Guided electromagnetic waves in the earth's crust 177

Electromagnetic scattering from a sphere 177

VLF radio propagation in an anisotropic ionosphere 177

Excitation of modes at very low frequency 177

Height-gain for VLF radio waves 177

Characteristics of an inhomogeneous D-layer at VLF 178

Propagation in a nonuniform earth-ionosphere waveguide. . 178

Microwave models for VLF propagation 178

Theory of magnetotelluric fields 179

2.3.5. Cryogenic engineering 179

Dielectric behavior of dense parahydrogen 179

Superconductivity 180

Magnetic properties in silicon steel 181

Low-temperature seals 181

Cryogenic literature service 181

Thermophysical properties of cryogenic materials 182

Fluid flow and heat transfer phenomena 182

Cryogenic instrumentation 183

Cryopropellant research 184

Refrigeration processes 185

Consultation and advisory services 185

Liquefied and purified gases 186

2.3.6. Building research 186

Building codes and safety standards 187

Creep and shrinkage of structural lightweight concretes 187

Joint sealants for building components 188

Waterproofing underground structures 188

Colloidal nature of asphalts 189

Photooxidation products in plastics identified 189

Fluid dynamics of plumbing 189

Test methods for air-conditioning units 189

Test methods for refrigerated trucks 190

Criteria for heating and air-conditioning ducts 190

Thermal emittance of ceramic oxides 190

Automation of thermal emittance measurements 191

VIII
2. Highlights of the research program—Continued

2.3. Special technical service programs—Continued

2.3.6. Building research-—Continued Page

Thermal conductivity reference materials 191

Thermal conductivity measurements by radial heat flow 192

Performance specification for insulated flat-roof constructions. . 192

Heat of hydration of portland cement 192

Electron capture of combustion inhibitors 193

Surface flame propagation 193

Fire research contracts 193

2.3.7. Weights and measures 194

3. Appendixes 197

3.1. Organization 197

3.2. Summary of NBS staff 203

3.3. Financial data on NBS program 204

3.4. Advisory committees 204

3.5. Awards and honors . . , ; 209

3.6. Education and training program 210

3.7. List of publications and patents 212

IX
r
1. GENERAL REVIEW

During the past year the National Bureau of Standards continued efforts

to focus and strengthen its technical program in support of the Nation's

technological advancement and economic growth. Major areas of effort were basic measurement standards, standard reference data, engineering

measurement standards, standard reference materials, radio propagation,

data-processing systems, and building research.

In this program the Bureau was concerned primarily with research and

technical services in the general field of physical measurement—a field of

basic importance to progress in commerce, industry, and science. Commerce

involves exchange of goods and services, and standards of physical measure- ment provide a basis for determining both quantity and quality in commercial exchange. Similarly, progress in science and in the application of

science to technology is based on the exchange of information, particularly

quantitative data, derived by the use of measurement standards. Thus, the

Bureau strives to advance measurement science and to further its application

in order to facilitate the reliable, efficient exchange of quantitative data in

science and engineering and of technological products and services in commerce.

Within the field of physical measurement, the Bureau is concerned with

four distinct but related types of standards: (1) Standards for the physical

quantities and units basic to the physical sciences and engineering; (2)

standards for the determination of quantity, quality, or performance of the

technological products and materials of commerce; (3) standard reference

data; and (4) standard reference materials for use in controlling chemical

processes and maintaining the accuracy of apparatus and equipment.

Through the years, in order to meet specific needs of the Government,

the Bureau has also undertaken responsibility within Government for operating central research and technical service programs in special areas. Such

programs are carried on by the Central Radio Propagation Laboratory, the

Data Processing Systems Laboratory, and the Building Research Division.

In addition to the above mission-oriented activities, the Bureau conducts

a broad program of exploratory or background research in the physical

sciences. The primary purpose of this work is to maintain and strengthen

the general scientific competence of the Bureau staff so that the Bureau can

Keep abreast of new developments in many fields, select the most effective

techniques for solving problems, and utilize quickly the results of scientific

work elsewhere. At the same time, however, the results of this research may

be expected to contribute substantially to the Nation s scientific progress.

1
This report attempts to present the highlights of the Bureau's program

for the fiscal year 1963. In Section 2, the body of the report, studies and

achievements from the various fields in which the Bureau is active have been

selected for brief presentation. However, the breadth of the program and

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 accomplishments and

activities of the year.

BASIC MEASUREMENT STANDARDS

The National Bureau of Standards is responsible for developing and

maintaining the national standards of physical measurement upon which all measurements in this country are based. As part of its measurement responsibility, the Bureau must also see that these standards are made available

to science, industry, and commerce through suitable calibration services.

During the last year the Bureau continued to be faced with the demands

of a rapidly expanding technology for greater accuracy and range in the

calibration services provided to laboratory, plant, and shop. A considerable portion of the research effort was therefore directed toward the exten- sion of precise standards and measurement techniques to new areas of

science and technology, and to new accuracies. Services added during the

year included calibration of microwave noise sources, at 9.0, 9.8, and 11.0

Gc/s, and power calibration of bolometer and bolometer-coupler units.

Insofar as possible, the Bureau restricted its own 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 by industry and the military services. Even so, the volume of NBS

calibration services continued at a high level (table 1). Over 75,000 cali- brations, having a total value of more than $2 million, were performed for

Government and industry. In an effort to cope more effectively with the calibration load, further

efforts were made to automate calibration procedures so that the output

data appear directly on punched cards or tape, ready for computer reduction. Two devices for this purpose were developed during the year: an

automatic thermocouple comparator and a data-recording assembly for

measurement of thermal emittance standards.

For several years the Bureau has been conducting a research program

looking toward the development of procedures for calibrating master gage

blocks on a regular basis to 1 part in 10 million. This work was begun,

at the request of machine tool manufacturers, in order to meet the stringent

calibration requirements imposed by the use of increasingly smaller toler- ances in industry. Attainment of the program's objective requires development of both highly stable gage blocks and ultra-precise measuring techniques. Two types of gage blocks have now been developed which are dimensionally stable to better than one 10-millionth of an inch per year, and

seven additional types have been produced which are stable to between one

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and two 10-miIlionths of an inch per year. In the measurement part of the

program, an investigation was begun to determine the thickness of the

molecular film between joined gage blocks, which in practice must be con- sidered as a part of the length of the blocks. In support of this research,

theory was developed which provided new knowledge about the behavior

of light beyond a surface normally thought to be totally reflective. In research to develop more accurate methods of measuring long distances, promising results were obtained through use of a helium-neon laser

as the infrared light source for a Michelson interferometer. With this

apparatus, interference fringes—normally visible over an optical path of

not more than 2 meters—were obtained over an optical path of approximately 200 meters. Thus use of a gaseous laser source appears to offer a means for measuring long distances to high accuracy. Work is now underway to stabilize the laser equipment so that interferometric calibrations of

length-measuring devices may be made with the laser. The accurate measurement of spectral irradiance has assumed increasing

importance in connection with studies of the irradiance to which space

vehicles will be subjected. During the year a new standard of spectral

irradiance was developed in the form of a 200-watt quartz-iodine lamp with

a coiled tungsten filament operating at about 3000 °K. The new standard

operates without auxiliary optics and provides relatively high spectral

irradiances.

Progress was made in research efforts seeking to develop standards and

measurement techniques for very high pressures. For use as a fixed point

in calibration work, the freezing pressure of mercury at 0 °C was determined to be 109,722 lb/in.2

, accurate to within ±30 lb/in.2

. A new piston

gage was under construction for use in a more accurate determination of

the phase transition of bismuth between 365,000 and 370,000 lb/in.2

. This

transition has been serving as the principal calibration point in the ultrahigh-pressure range.

A number of advances were made in the field of electrical measurement.

For example, a new differential a-c-d-c transfer standard was developed to meet the growing need for greater speed and accuracy in measuring a-c voltages at audiofrequencies. Unlike older forms of a-c-d-c transfer instruments, in which successive comparisons were required, this instrument can be used for the simultaneous comparison of an unknown a-c voltage with a known d-c voltage. It provides a usable precision of 10 parts per million.

A permanent adjustable standard of magnetic susceptibility was designed

and was incorporated into a magnetic susceptibility bridge of high accuracy

and sensitivity. Other apparatus was constructed for determining absolute

magnetic susceptibilities down to liquid helium temperatures.

A microwave phase-shift measuring system was developed that is capable

of measuring phase shift to an accuracy within 0.01 degree. The system

is now ready for use in a national microwave phase-shift calibration service.

Research continued on atomic standards of frequency and time. The

United States Frequency Standard, which is derived from a natural fre4
quency of the cesium atom, is now accurate to better than one second in

3,000 years. During the year one of the two cesium beam frequency standards that have been used in maintaining the national standard was converted

to a thallium beam for the purpose of evaluating a thallium transition as

the standard of frequency, and it appears that an improvement of one order

of magnitude in accuracy over that of cesium can be expected. Also, a new

cesium beam frequency standard was completed which promises to have a

precision about twice that of the other cesium standard now in use. The

United States Frequency Standard provided a basis for the establishment

of an NBS atomic time scale. The NBS atomic time was related to the time

pulses of NBS radio station WWV, to the atomic time kept by the Naval

Observatory, and to the time pulses of the Loran-C master station at Cape

Fear, N.C.

The Bureau continued to cooperate closely with the National Conference

of Standards Laboratories. This Conference and its continuing committees

bring together representatives from military, industrial, and university standards laboratories, to promote cooperative action on common problems of

the management and operation of measurement standards and calibration

laboratories. In August 1962 the Bureau was host to the first national

meeting of this organization at the NBS Boulder Laboratories. Over 600

persons attended the Conference, the proceedings of which were published

by the Bureau.

The Bureau also cooperated in an interservice measurement audit which

is designed to promote measurement agreement among the military- services.

Items being measured include resistance and capacitance standards, a fre- quency meter, an optical polygon, and a vibration pickup. Results of tests on these items by the Bureau, the Army, Navy, Air Force, and Sandia

Corporation representing the Atomic Energy Commission, will be analyzed

by the Air Force.

A series of precision measurement seminars, designed to provide an opportunity for qualified senior people from other organizations to benefit

from the Bureau's long experience in certain measurement areas, was an- nounced during the year. Attendance at these seminars, in the fields of

length, acoustics, frequency comparison techniques, attenuation at communications frequencies, and precision and accuracy, was limited to permit detailed individual participation. Registrants were selected from Government,

industry, and university laboratories.

During the year a uniform format for reporting the results of calibrations

and tests was adopted. All such results are now issued in report form, supplemented by a letter of formal certification when required by law or special

conditions. Generally the reports include more useful discussion and evaluation of the uncertainties involved than was formerly provided.

The preparation of charts showing NBS capabilities in various measure- ment areas was continued. Several of these charts are reproduced on

page 6.
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ACCURACY OF LENGTH MEASUREMENTS AT NATIONAL BUREAU OF STANDARDS, 1962 EXISTING CAPABILITIES OBJECT OF EXISTING PROJECTS

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CAPACITANCE IN MICROFARADS

Charts depicting NBS capabilities in the measurement of length (top) and ca- pacitance (bottom).

6
STANDARD REFERENCE DATA

During 1963 a considerable portion of the Bureau's research effort was

devoted to the development of standard reference data in the physical sci- ences. In addition a number of data centers for compilation and storage

of critically evaluated data were operated in such areas as chemical thermodynamics, atomic transition probabilities, atomic cross sections, ceramic

phase equilibria, and cryogenics. During the year, the Data Center on Atomic Collision Cross Sections completed a survey of all literature reporting

cross sections for two-body collisions involving a free electron. This Center

is now providing bibliographic searches for the general scientific community

and is preparing a complete bibliography by subject classification. The

Data Center on Atomic Transition Probabilities published a bibliography

containing a complete listing of pertinent articles in this field and had almost

completed a critical evaluation of transition probability data on the first 10 elements.

The Cryogenic Engineering Data Center continued to serve as a clearing

house for research and development literature on cryogenics. During the

year some 4100 new references were coded and entered into the Center's

storage and retrieval system. Special attention was given to low-temperature

data on the properties of solids and fluids; 1500 of the new entries were

in these categories. A number of extensive bibliographies on properties of

materials were compiled, and an estimated 20,000 items of NBS literature were distributed in response to some 1500 requests.

An important area of research was concerned with the application of the

wall-stabilized arc for the measurement of transition probabilities and to gain a better understanding of high-temperature plasma phenomena. The

shifts and widths of several oxygen lines were measured and the results were

found to be in good agreement with recent theories on line broadening in

dense plasmas.

In other studies using a gas-stabilized arc, transition probabilities for

105 lines in the spectrum of neutral atomic iron were redetermined to higher

precision than in previous work.

Apparatus was constructed to study the variation in dielectric constant

and relaxation time for liquids and supercooled liquids at pressures up

2000 atmospheres and at temperatures from liquid nitrogen temperature

( — 196 °C) to about 50 °C. By suitable choices of temperature and pressure, measurements with this apparatus may be conducted at constant density

in order to provide more definitive tests of dielectric theory.

A microwave spectrometer which can be operated at temperatures up to 1000 °C was constructed and applied successfully to several problems in

high-temperature chemistry. This instrument permits the extension of powerful microwave techniques to the identification and structure determination

of molecules and radicals that are present in high-temperature systems.

Spectra for such molecules as aluminum monofluoride and aluminum monochloride, which do not exist at room temperature but which are important

constituents in rocket combustion systems, have been detected and analyzed.

714-691 0—64 2 7
New information on the atomic energy levels of the rare gases helium,

neon, and argon was obtained in a series of independent experiments which

utilized both electron and photon interactions. Optical photons in the far

ultraviolet, produced by the accelerated electrons in the Bureau's 180-Mev

synchrotron, were used in studies of the absorption properties of the three

gases, which resulted in the discovery of a number of new atomic energy

levels in these gases. These findings were confirmed in observations on

energy losses of electrons scattered by the gases and in theoretical studies

of their ultraviolet absorption properties.

Determination of the structure of carbon suboxide (C3 02 ) resolved a

scientific controversy of 30 years' standing. Through analysis of a highresolution infrared absorption spectrum, conclusive evidence was obtained

that the molecule is a straight chain consisting of three carbon atoms with an oxygen atom at each end. Since 1933, when the carbon suboxide molecule was reported to have a dipole moment, indicating some sort of bent structure, molecular spectroscopists have been divided in support of linear and

nonlinear configurations. Valence theory predicts the linear form, but

earlier studies, handicapped by inadequate resolution and impure samples,

provided inconclusive and contradictory results. Finally, the Bureau obtained new evidence by using ultra-high-resolution techniques to determine

the rotational fine structure of a band in the 3-micron region.

National Standard Reference Data System. In June 1963, the Office

of Science and Technology, acting on a recommendation of the Federal

Council for Science and Technology, established a National Standard Ref- erence Data System (NSRDS) to provide critically evaluated data in the

physical sciences on a national basis. The Bureau was given responsibility

for administering the System, which will centralize a large part of the present

data-compiling activities of a number of Government agencies.

The aim of the NSRDS is to develop a storehouse of standard reference

data to assist in the advancement of science, technology, and the national

economy. This result is to be achieved through a broad-based, comprehensive effort by scientists both in and outside the Government.

The Bureau, as well as other organizations in this country and abroad,

has been active in the compilation of standard reference data for many years.

However, in view of the great accumulation of unevaluated data over the past

few years, the present accelerated production of new data, and the urgent

needs of American science and industry, it has become apparent that a substantially greater effort, planned and coordinated on a national basis, is needed.

The National Standard Reference Data System will consist of a National

Standard Reference Data Center at the Bureau, and various other Standard

Reference Data Centers in other Government agencies and at universities,

research institutes, and other non-Government organizations. In order for

such centers to be a part of the NSRDS, they will be required to meet quality

standards established by the Bureau. However, the independent and operational status of existing critical data projects will be encouraged.

8
An Advisory Board will review and recommend policy relative to the

operation of the NSRDS. It will include, among others, representation

from the National Academy of Sciences, National Science Foundation, and

Federal agencies engaged in research and development.

The NSRDS will be conducted as a decentralized operation across the

country, with central coordination by the Bureau. According to present

plans, the data input will come from scientists in many different locations

who will comprehensively review the literature in their fields of specialization and will critically evaluate the data it contains. The evaluated data will

be classified and stored at the Bureau and will be disseminated through a

series of services tailored to user needs in science and industry. In choosing

work to be undertaken, the Bureau will be assisted by the Advisory Board,

interagency panels, expert consultants in the subject-matter areas, and working committees of the scientific and engineering societies and industry asso- ciations that are active in the field of critical data.

ENGINEERING MEASUREMENT STANDARDS

The Bureau cooperates extensively with recognized standardizing bodies

in the development of codes, specifications, standards of practice, and methods of test for technological devices, products, and services. In general, the

Bureau contributes by conducting research to provide test methods, data on

materials, and measurement standards; the sponsoring organization supplies

other technical data and promulgates the finished documents in the form of

codes, specifications, or engineering standards. The Bureau is in a position

to provide material assistance in this field because of the active participation

of its staff members in the work of numerous technical societies and standardization groups such as the American Standards Association, the American

Society for Testing and Materials, and the Society of the Plastics Industry.

The Bureau also plays an active role in the development of government

purchase specifications. During fiscal 1963, at the request of the General

Services Administration, the Bureau accepted responsibility for preparing

and maintaining two additional Federal Specifications, making a total of

154 for which it now has this responsibility. The Bureau also reviewed

approximately 600 proposed specifications both for GSA and for other

agencies to determine their suitability for use by the Federal Government.

In June 1963, the scope of the Bureau's program in technological standards was increased with the transfer of the Commodity Standards Division

of the Office of Technical Services, U.S. Department of Commerce, to the

National Bureau of Standards. The transferred activity provides assistance

to industry, business, and consumers in the development and acceptance of

voluntary trade standards that define quality levels for products and aid in

holding variety to a minimum.

In the last year, many experimental data were obtained for developing

and improving building codes, standards for building materials, and methods

of testing building materials and equipment. Typical of this work were

investigations of the creep and shrinkage of structural lightweight concrete,

9
studies of methods of waterproofing underground structures, and work to extend methods of measuring thermal emittance and thermal conductivity

to higher temperatures.

Fiberglass- rein forced plastics are being employed for many structural

purposes today. However, weather exposure decreases their strength and

light-transmitting characteristics. During 1963 the Bureau developed a

sensitive colorimetric method for determining degradation of fiberglassreinforced polyester plastics. This method provides a rapid, reproducible means for predicting durability.

Laboratory investigations leading to the development of a testing and

rating method for refrigerated trucks were carried out under the joint sponsorship of the U.S. Department of Agriculture, the Truck Body and Equipment Association, and the Bureau. An apparatus for simulating the effect

of solar radiation on the cooling load of stationary refrigerated trucks was

designed and constructed. It was found that the air and moisture trans- mission through the body was significantly different for different constructions, and that the effect of solar radiation could be satisfactorily accounted

for by a correction factor to the steady state heat transfer.

In other research for development of test methods, a technique was devised for using a digital computer to analyze the microstructure of metals

and alloys. This computer technique takes the place of tedious manual

operations in determining the size, shape, and number of crystals or grains

found in photomicrographs of metal or alloy structures. In this way analyses

are accomplished up to a thousand times more quickly than has been possible

with conventional manual methods. Thus far the technique has been used

in studies of the graphite content of cast iron and of niobium-tin phases in

experimental superconductor alloys. The rapid, accurate results obtained

in these studies demonstrate the feasibility of employing computer programs

in micrographic analyses, and suggest the use of the technique in other areas, such as petrography, microbiology, astronomy, and photogrammetry.

A new three-terminal dielectric cell was completed and used to make precise dielectric constant measurements by the two-fluid method which requires no electrodes. With this apparatus the dielectric constant of a disk specimen

can be obtained to within better than 200 parts per million between 100

cycles per second and 50 kilocycles per second.

A scheme of color tests was developed for identifying the five antioxidants

commonly used in styrene-butadiene synthetic rubbers. These antioxidants

include naphthylamine and diphenylamine compounds, styrenated phenols,

and alkylated arylphosphites. By using specified successive tests involving

two or more of a group of 12 reagents, the uncertainty of distinguishing

between similar colors obtained with a single test was overcome. An improved analytical procedure was developed for measuring the thiosulfate radical remaining in photographic film after processing. Such tests are routinely conducted to assure conformance to microfilming specifications.

The new procedure reveals two or three times as much residual thiosulfate

10
as does the current standard analytical method which has been in use for the

past 30 years.

During fiscal year 1963, the Bureau tested 53,877 items ranging from

dry cells to building materials (table 2). Most of the tests were on items

purchased by other Federal agencies that lacked the facilities to make the

tests themselves.

STANDARD REFERENCE MATERIALS

During fiscal year 1963 the Bureau distributed 72,074 samples of standard

materials, having a value of $551,264, to other laboratories (table 3).

Nearly 600 different standard materials are at present available—principally

chemicals, ceramics, metals, and radioactive nuclides. New standard materials added during the year included radioactivity standards of iodine 125

and cerium 139; two polystyrene molecular weight standards; five portland

cement standards; a standard soda-lime-silica glass; and various alloys for

spectroscopic standardization. All are certified either for chemical composition or with respect to a specific physical or chemical property such as melting point, viscosity, or color.

In research to develop new standard materials, a technique known as

dielectric cryometry was devised for precise determinations of purity. In

A new method of producing glass with controlled light scattering properties led

to these prototype turbidity standards. They are now being studied as possible

replacements for the less durable plastic and liquid standards presently in use. (See p. 11.)

11
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13
this method, measurements of the change in dielectric constants are used to determine ihc solid-liquid ratios corresponding to various freezing for melting) temperatures of the substance studied. An advantage of the method

is that it permits use of relatively small samples (4 to 10 ml) to determine

purity. In studies of phase changes in silica-metal oxide systems, a means was

found for producing glasses having a controllable degree of light scattering.

Glasses of this type are being evaluated as turbidity standards to replace the

less durable plastic and liquid standards that are now in use. Because of its reproducibility, the pH of solutions in alcohol-water solvents,

determined with commercial electrometric pH equipment, is an important

control variable in certain research operations as well as in industry and

commerce. Until recently, however, pH numbers determined in the conventional way could be interpreted in terms of hydrogen ion concentration or

activity only when the solvent medium was pure water. During 1963, a scale

of pH (designated pH*) for methanol-water and ethanol-water media was shown to be practical, and procedures were devised for assigning standard

values of pH* to reference solutions. The pH* determined experimentally

bears a simple relation to dissociation constants and other thermodynamic

quantities in the same medium and, as such, should have wide application

in many branches of chemistry and biology.

SPECIAL CENTRAL MISSIONS

Radio Propagation. Within the Federal Government, the NBS Central Radio Propagation Laboratory fCRPL) has been given the central responsibility for collecting, analyzing, and disseminating information on the

propagation of radio waves at all frequencies along the surface of the earth,

through the atmosphere, and in outer space. To carry out this responsibility,

it conducts research on the nature of the waves, the media through which

they are transmitted, and the interaction of the waves with the media.

During 1963, ground-based studies of the ionosphere in the vicinity of the

earth's equator were made by a scatter radar technique at the Jicamarca

(Peru) Observatory of CRPL and of the Instituto Geofisico de Huancayo

(Peru). This observatory, located on the magnetic equator near Lima,

employs a 6-million-watt transmitter and a 22-acre antenna to transmit a very-high-frequency radio wave of extremely short duration to great heights.

The antenna is also used to detect the faint reradiation of the pulsed radio wave by free electrons in the upper atmosphere. The primary function of

the installation is to study the distribution of electron density with height

out to 6,000 miles or more above the earth's surface.

In cooperation with the Instituto Geofisico de Huancayo, the Jicamarca

Observatory made a series of measurements of the synchrotron radiation

that was emitted by the manmade belt of high-energy electrons which formed

as a result of the high-altitude nuclear detonation occurring above Johnston

14
Island in the Pacific on July 9, 1962. From these measurements, made at 30 and 50 megacycles per second, the number, energy spectrum, and decay

rate of the electrons were derived—information that will help improve understanding of the physics of the upper atmosphere. The extremely high radar

sensitivity available at Jicamarca also made possible the detection of radar

echoes from Venus when the planet was observable from Lima during the

first week of December 1962.

Data-Processing Systems. In the rapidly advancing field of auto- matic data processing, the Bureau serves the Federal Government as a center

for research and services to promote more effective utilization of dataprocessing facilities within the Government. With the increasing variety

and complexity of governmental applications of data processing, the scope

of the research program in this field has correspondingly increased until it now utilizes the techniques of several scientific disciplines. Representative

activities during the past year included exploration of the operational characteristics of new components to determine their suitability for computer

circuitry, studies of the properties of materials used in new components, and

development of techniques for extending automated procedures in areas such

as the processing of scientific information. Studies were conducted on ultra- thin ferromagnetic films as potential high-speed random access memory ele- ments, and an investigation was begun of the technique of quantitative

analysis of thin films by X-ray fluorescence. Research continued on simulation and characterization of semiconductor devices such as tunnel diodes

and epitaxial transistors. In connection with this work, a counter circuit

incorporating tunnel diode-transistor type of circuitry was developed that

is capable of counting up to 80 megapulses.

Building Research. Studies were conducted in physics, chemistry,

and engineering to develop new knowledge relating to building materials,

equipment, and structures. For example, work was done on the reactions

which take place in concrete upon setting, involving heats of formation of

many compounds, and on the reactions which take place after setting, in- volving the corrosion of concrete reinforcements. Other typical investigations dealt with methods of controlling unwanted fires, heat transfer in

structures, mechanical systems for buildings, metallic building materials, and

properties of asphalts. During the year, experimental results were obtained

which support the colloidal theory of asphalt: the presence of an electric

charge on dispersed asphalt particles was detected and measured. Although

the theory of the colloidal nature of asphalts has received wide support since

its proposal many years ago, until this finding little if any experimental evidence to support the theory had been reported.

CONSULTING SERVICES

To a considerable extent, the Bureau's consulting activities are a natural

result of the broad scope of its program and the special competence of many

of its staff in the physical sciences and engineering. Services of this kind

15
are rendered to other Federal agencies, to State and municipal governments,

and to various industrial groups.

Consulting services to the Federal Government ranged from the supplying

of specific technical information upon request to long-range projects that were within the NBS mission but were sponsored by other agencies. Many

such projects were in the field of automatic data processing. For example,

a portable peer-rating machine, which rapidly computes group ratings of

individuals, was developed for the U.S. Army Personnel Research Office.

At the request of the Office of Technical Services, U.S. Department of Commerce, a system was designed for mechanizing the preparation of announce- ment bulletins and indexes, inventory control, and storage and retrieval of

documents- In work done for the Patent Office, a remote inquiry station was designed to permit easy and rapid communication between human operators at their respective locations and a central data processor, all of which

might be located within one building or might be separated by hundreds or thousands of miles. Under the sponsorship of the Navy's Bureau of Supplies

and Accounts, assistance was given in the development of an efficient system

to procure and distribute the thousands of items required within the Naval

establishment and to control their purchase, storage, and distribution. An

information-handling system was designed for the Naval Intelligence Agency

to provide an efficient, low-cost means of storing, searching, and retrieving

intelligence data.

Consultative services were provided to the Weather Bureau on the trans- mission and processing of photographic and infrared data generated by the

new weather satellites of the NIMBUS series. Systems analyses were con- tinued to determine the feasibility of utilizing automatic data-processing

techniques in the activities and operations of the Interstate Commerce

Commission.

Assistance to State and municipal governments was 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 regulatory

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. Over 400 delegates from 39 states, Puerto Rico, and several

foreign countries attended the 48th annual meeting of this Conference, held

in Washington, D.C., June 10 to 14, 1963, under NBS sponsorship.

Important means of Bureau-industry cooperation were the Research Associate 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 associates who are paid by the sponsor but otherwise function as members of

the Bureau staff. At the present time the following groups are supporting

research associates at the Bureau:

16
Sponsor

American Dental Association

American Electroplaters' Society

American Society for Testing and Materials

American Standards Association

Asphalt Roofing Industry Bureau

Bone Char Research Project, Inc. Calcium Chloride Institute NBS—Joint Committee on Chemical Analysis by Powder Diffraction Methods:

ASTM, American Crystallographic Assoc.,

Institute of Physics (British), National

Assoc. of Corrosion Engineers

National Academy of Sciences-National

Research Council

Porcelain Enamel Institute

Field of Activity

Dental research Galvanic effects associated with coating

failure Properties of electrodeposited copper

Cement and concrete reference laboratory

Codes, specifications, and standards

Asphalt roofing research

Studies of adsorption and adsorbents

Hydration of portland cement

Standard X-ray diffraction powder patterns

Atomic physics

Porcelain enameled metals

The donor program was authorized in 1950 by Public Law 619 under

which the Bureau may accept funds for the purpose of furthering its work.

This arrangement permits individuals as well as technical, industrial, and

commercial organizations to support work at the Bureau when the results are expected to be of value to the general public. During the past year, the

following projects were supported by gifts:

Donor

American Iron and Steel Institute

Brown and Sharpe Manufacturing Co. Corrosion Research Council of the Engineering Foundation

Edward Mallinckrodt, Jr. Expanded Shale Clay and Slate Institute International Business Machines

Link Aviation, Inc. Pratt and Whitney

The Edward Orton Jr. Ceramic

Foundation

Field of Activity

Durability of steel pilings

Grant for standard samples program

Gage block program

Durability of steel pilings

Theoretical chemistry

Creep and shrinkage of concrete Gage block program

Gage block program

Gage block program

Basic clay research

In the project sponsored by the American Iron and Steel Institute, the

Bureau investigated the extent of corrosion in steel piling that had been

driven into the ground. Data obtained from pilings which had been in

service in different geographic locations for 7 to 40 years showed that the

strength and useful life of the driven piling were not materially affected by

corrosion, apparently because of the deficiency of oxygen in "undisturbed"

natural soils. These findings are in sharp contrast to those of earlier cor- rosion studies in which metal specimens such as pipe lines that had been

buried under "disturbed" soil conditions exhibited varying degrees of cor- rosion. The disparate results are attributed to the differences in oxygen

content between the "undisturbed" piling environment and the "disturbed"

pipeline environment. Studies are now being made to determine the rea- sons for this difference.

17
BACKGROUND RESEARCH

Study of the transitions that materials undergo at high pressures aids

in defining interatomic forces and the perturbing effects of neighboring

atoms on one another. During the year direct visual observations were made of phase transitions and other changes occurring in a variety of

polymers subjected to extremely high pressures—up to one million pounds

per square inch. The polymers were compressed between diamond anvils

which served both as load-bearing surfaces and as light-transmitting media,

and a microscope was focused onto the specimen through the diamond. By

passing infrared and X-rays through the diamond pressure cell or by viewing the transformations through a microscope, it is possible to relate changes

in crystal structures to changes in bond energies, force constants, and vibration frequencies.

Large single crystals of metals, semiconductors, and other materials are needed for many purposes in science and industry. However, single crystals

of most materials of practical interest are difficult to grow. The Bureau has

been making an effort to learn more about crystal-growing mechanisms

through study of simpler substances. It was found that at very low temperatures large crystals of rare gases may be prepared and studied with

many of the same techniques that have been used at higher temperatures on other substances. These gases are prototype molecular solids in which

the forces among the molecules are so weak that they crystallize at low temperatures. Argon and krypton crystals were grown at temperatures near

the triple points of these elements, respectively 84 °K and 116 °K. Studies

of the properties and growth characteristics of these crystals were found

to be easily correlated with theory.

In cooperation with the George Washington University, a study was made of the properties of coordination polymers formed by combining the

ligand fei's (8-hydroxy-5-quinolyl) methane with divalent manganese, cobalt,

nickel, copper, and zinc. Among the many potential applications for such

polymers is the fabrication of missile and rocket components. Results of

the study show that the decomposition temperatures of the polymers, and

hence their thermal stabilities, are directly related to the atomic numbers of

the coordinated metals. The findings has led to a better understanding of the

mechanism governing polymer decomposition and may be of particular use

in predicting the thermal behavior of coordinated systems when only a minimum of experimental data is available.

Continuing research in statistical engineering dealt with applications of

probability theory to problems of the reliability of complex systems. A

mathematical study was made of the reliability of a system with spare parts,

where the spare parts can fail in storage as well as in use. An investigation was begun of mathematical models for the description of changes through

time in the probability distributions of characteristics of electronic devices;

the dependence of these distributions on age and stress level was considered.

General areas of investigation in operations research included game theory,

graph theory, weapon system simulation, Boolean functions (important

18
in network circuit theory), and mathematical models of distribution net- works. A number of mathematical topics relating to the "warehouse problem" (optimal location of a single processing facility) were identified and

explored.

Research in mathematical physics continued to be directed toward the

application of mathematical techniques to the solution of problems in physics

and engineering. Investigations in progress included the determination of

bounds on solutions of problems involving elliptic operators, especially those

of elasticity; the application of the "stroboscopic" method to the study

of nonlinear ordinary differential equations arising from vibration, acoustical,

and electrical circuit problems; the interaction of solar corpuscular radiation and the earth's magnetic field; and studies of dynamic phenomena

which may affect the operation of plasma propulsion devices.

INTERNAL SUPPORT ACTIVITIES

Progress continued in the design and construction of the NBS linear

accelerator, Linac, now scheduled for installation at the Bureau's new

Gaithersburg (Md.) site in the spring of 1964. This accelerator will produce

one of the world's most intense electron beams with energies up to 100 million

electron volts, making it possible for the Bureau to enter new areas of nuclear

and atomic physics. Tests of the first prototype accelerator section were completed during the year, and a number of investigations were undertaken

which allow definition of the ultimate performance of the NBS linear ac- celerator facility and of other comparable facilities. A $5 million contract was awarded for construction of a high-flux research

reactor and associated laboratories at the Gaithersburg site. This reactor,

to be known as the NBSR, will enable the Bureau to fulfill its growing responsibilities in the many rapidly expanding fields of atomic energy. It will

be used to advance the measurement, analysis, and understanding of radiation effects on substances of all kinds.

INTERNATIONAL ACTIVITIES

On an international basis, the Bureau represents the interests of the Government and American science in matters dealing with the establishment and

maintenance of standards and the. establishment of values for scientific constants. Most of this work is done through participation in a large number

of international groups such as the General Conference on Weights and

Measures, International Union of Pure and Applied Physics, International

Union of Pure and Applied Chemistry, International Scientific Radio Union,

International Commission on Illumination, and International Organization

for Standardization.

The Bureau, in cooperation with the Office of Technical Services, U.S.

Department of Commerce, has been actively participating, through the

American Standards Association, in the planning and development of panAmerican standards for commodities including textiles; iron and steel; cement

19
Members of the NBS Boulder Laboratories staff explain construction details of

the NBS microcalorimeter—the U.S. standard of microwave power—to Dr.

Wolfdietrich H. Schaffeld (.right), Head of the Microwave Physics Laboratory,

Physikalisch Technische Bundesanstalt, Braunschweig, Germany. (See

P. 19.)

and concrete; hides, leather, and tanning materials; and electrical equipment. This program is basic to the economic development of the Latin American countries and to the expansion of trade among these countries and

between them and the United States. The Bureau has rendered assistance

in the field of weights and measures to several Latin American countries that

have requested it, and prototype standards suitable for use as the national

standards of developing countries are being procured for demonstration

anutraining purposes.

Another form of international cooperation is the reception of foreign

scientists as guest workers or visitors, and the training of foreign specialists

in the Bureau s laboratories. During the past year, 662 foreign scientists

from 45 countries came to the Bureau as visitors, and 138 trainees and guest

workers were received.

The Bureau continued a program initiated the previous year in which

funds are granted to scientific laboratories in certain foreign countries

in order to support research directly related to the Bureau's mission.

In the past two years, 29 grants and contracts totaling more than a million

20
dollars have been awarded to institutions in India, Israel, and Pakistan.

These awards are financed from excess balances of local-currency funds ac- cruing to the United States from the sale of surplus farm products in past

years. Recent awards have been for work on imperfections in crystals, dynamics of crystal lattices, nature of the Moessbauer effect, analysis of polymers, vapor pressure of refractories, and reflection of radio waves on

ionospheric layers.

In addition to the scientific results of these activities, the program has

resulted in an increased interest among foreign scientists in the kinds of

problems that are relevant to the Bureau's mission, in greater awareness among Bureau staff members of the scientific potential in other countries, and

in intensified communication and exchange of visits. In June 1963 a seven-man team of measurement specialists from this

country, headed by an Associate Director of the Bureau, visited the Soviet

Union for a month-long tour of various measurement laboratories. The

team consisted of six NBS staff members and one representative of industry.

Plans were made for a similar team of Soviet metrologists to visit the United

States later in the year. These visits are being conducted under the terms

of a United States-U.S.S.R. agreement for the interchange of information

and the exchange of visits by teams in 13 fields of technology. The U.S.

State Department, under whose general control the exchange program is conducted in this country, requested that the Bureau arrange for the ex- change of persons from the area of high-precision measurement standards.

ADMINISTRATIVE ACTIVITIES

During the past year the Bureau initiated a critical examination of its management techniques for determining the needs and priorities of the users

of its services and for defining the objectives of its programs to assure the

most efficient application of NBS resources. Particular attention has been

given to the identification and emphasis of programs that support directly

the broad responsibilities of the Department of Commerce for promoting

economic growth through science and technology. New techniques are being

developed for the formulation, management, and evaluation of NBS programs in terms of certain broad program categories or "mission components" which have been identified.

It has been recognized that the central program of the Bureau is concerned

with four related types of standards which are of interest to two broad

customer groups. These are ( 1 ) basic measurement standards for the physical quantities and units, used by the scientific and engineering community,

(2) technological standards such as codes, methods of test, commodity standards, and engineering standards needed by the industrial community to determine the quantity, quality, or performance of technological products

and materials of commerce, (3) standard reference data consisting of critically evaluated data on the physical and chemical properties of matter and

materials, and (4) standard reference materials for use in controlling in- dustrial processes and maintaining the accuracy of measuring equipment.

21
The latter two categories of standards are needed by both customer groups.

In examining the total program of the Bureau, certain additional mission

components have been identified for management purposes. These include

the broad program of background research conducted by the Bureau to maintain contact with impending developments and to provide general scientific

competence, extensive consultative and advisory services provided for Government and private organization, and various technical services which supply internal support for NBS activities. In addition, the Bureau operates

research and technical service programs in certain "special mission" areas

for which the Bureau has a recognized central responsibility within Government. The Bureau's Central Radio Propagation Laboratory, Data Processing Systems Division, and Building Research Division conduct programs

of this type.

With the exception of these "special mission" organizations, NBS technical divisions are organized along the classical lines of science and engineering, including divisions concerned with electricity, heat, mechanics,

analytical chemistry, atomic physics, etc. It has been necessary, therefore,

to devise new management techniques for examining the programs of these

subject matter divisions in terms of their contribution to the broader mission

components of the Bureau. It is believed that these management innovations will enable the Bureau to be more responsive to the needs bf its cus- tomers and to achieve better balance in the application of its resources. To facilitate this new program management plan and to strengthen the

Bureau's activities which foster industrial technology, a new position of

Deputy Director for Technological Standards and Services was created.

This position will have responsibility for NBS programs which contribute

directly to the development of commercial and industrial standards and test methods. Included are the commodity standards and international standards programs, which have been conducted by the Office of Technical Services

of the Department of Commerce since 1946, and were returned to the

Bureau near the end of the year. Assignment of these functions to the Bureau concentrates in the Bureau all of the Department of Commerce programs

concerned with the development of industrial standards which provide the

common basis for exchange of technological products and services in in- dustry and commerce. The former Deputy Director has been redesignated Deputy Director for

Basic Standards and Services. He will be responsible for NBS programs

concerned with the development of basic measurement standards and sys- tems, for the technical services associated with the dissemination of these

standards, and for the greatly expanded effort on standard reference data

which will result from the recent assignment to the Bureau of responsibility for coordination of a National Standard Reference Data System (see

p. 8).

Funds obligated by the Bureau during fiscal year 1963 totaled $59,021,000,

including $9,627,000 for facilities. Of the $49,394,000 available for support

of the technical program, $28,492,000 came from direct appropriations to

22
The Engineering Mechanics Laboratory at the new NBS site in Gaithersburg

(Md.) is now being occupied by the first working groups to move to their new

quarters. (Seep. 21.)

the Bureau and $14,584,000 from other Government agencies and private

sources. In addition, calibrations, tests, and other reimbursable services

amounting to $6,318,000 were performed during the year. A more complete presentation of financial data can be found in appendix 3.3. The total staff of the Bureau at the end of the fiscal year was 4,160; 2,754

of these staff members were employed in the Bureau's Washington 'Laboratories, and most of the remainder were attached to the NBS Boulder Laboratories in Boulder, Colo. Additional information on staffing is available

in appendix 3.2. Construction of Phase I of the Bureau's new laboratories near Gaithersburg, Md., was largely completed during the year and substantial progress was made on the remainder of the facility. Phase I, which will be occupied

in the near future, includes a boiler plant that will supply heat and cooling

for all buildings on the site, and the engineering mechanics laboratory.

Erection of the large force-measuring machines that are an important feature

of the new mechanics laboratory is in progress, but will not be completed

for several months.

Construction of Phase II was started in July 1962 and is well under way.

This phase includes four buildings to house the administrative and service

activities of the Bureau and the radiation physics laboratory. The latter building will contain the Bureau's new linear accelerator. Construction also was started on the NBS research reactor near the end of the year (see

p. 19).

Phase III was started in October 1962 when a contract was awarded for

constructing the substructures of the seven general purpose laboratories.

This work was nearing completion at the end of the fiscal year and bids had

been requested for the remaining construction on these laboratories.

714-691 0—64 3 23
Phase IV, which includes various special-purpose laboratories, is the last

element of the Gaithersburg facility currently planned and the only one

not now under construction. Planning for this phase continued during the

year. Also in the planning stage is a major new building to house the

rapidly expanding activities of the radio standards laboratory at Boulder,

Colo.

PUBLICATIONS AND TECHNICAL INFORMATION

To be fully useful, the information developed in the Bureau's work must

be communicated to the scientific and industrial community for application

in the laboratory and on the production line. Many channels are maintained to facilitate this flow of information.

Probably the main channel is the Bureau's publications program. NBS

publications are therefore suggestive of the scope and level of its technical

program. During the year these totaled 1,122 formally published papers

and documents. In addition, some 420 classified and unclassified reports were issued to other Government agencies.

Among the major publications of the year was Dr. F. B. Silsbee's Systems

of Electrical Units (NBS Mono. 56) . It surveys the various systems of units

used in electricity and magnetism and briefly traces their historical development. Dr. Silsbee, one of the world's leading authorities in the field,

compares the views of the theoretician and the experimentalist in the derivation of the units.

In his discussion, Dr. Silsbee points out that preferences and philosophies

regarding systems of units have changed substantially over the years and

are still under discussion by international standardizing bodies. This

Monograph is intended as a stimulus to further development, understanding,

and utilization of systems of electrical units.

Another major publication was Tensile and Impact Properties of Selected

Materials from 20 to 300 °K (NBS Mono. 63) . The materials referred to are

structural materials for use in low-temperature applications—alloys of

aluminum, cobalt, copper, iron, nickel, and titanium, and two metal-bonded

carbides. Included are tensile strength, yield strength, elongation, and

reduction of area values ; stress-strain curves ; and impact data.

Standard X-ray Diffraction Powder Patterns (NBS Mono. 25, Section 2)

the twelfth in a series with this title, also appeared this year. This volume

contains 37 standard patterns to aid chemists in identifying unknown crystalline materials by X-ray diffraction. Radiobiological Dosimetry: Recommendations of the International Commission on Radiological Units and

Measurement (NBS Handb. 88) is in effect a handbook for the radiobiologist and considers methods for improving accuracy and comparability of

absorbed dose measurements.

Of the 1,122 formal publications issued during the year, 180 were published

in the Journal of Research, and 736 in the journals of professional and

scientific societies. Also, 132 summary articles were presented in the Bureau's monthly Technical News Bulletin. In the nonperiodical series of

24
publications, 74 papers were published: 18 in the Monograph series; 4 in

the Handbook series; 3 in the Miscellaneous Publication series; and 49 in

the Technical Note series.

Central Radio Propagation Laboratory Ionospheric Predictions, the Bureau's third periodical, which is published for a one-month period three

months in advance, presented radio propagation data needed for determining

the best radiofrequencies to use in long-range radio communications. A

fundamental change in form and content was made in the Predictions beginning with the January 1963 issue. The predictions are now prepared

by a method of numerical mapping using a high-speed electronic computer.

The new format includes tables of coefficients which, when used as input

data with a suitable program, make possible the use of a computer

for calculation of detailed high-frequency radio propagation predictions for

any application. World prediction maps for every even hour, Universal

Time, are provided for subscribers without access to computer.

A list of publications for the fiscal year, which includes several papers

published in the previous year but not reported, is given in the appendix,

section 3.7 (p. 212).

Secretary of Commerce Luther H. Hodges (right foreground), Assistant Secretary of Commerce for Science and Technology J. Herbert Hollomon (speaking), and NBS Director A. V. Astin (center) at a preview of the NBS Open

House commemorating the Commerce Department's 60th Anniversary. The

special preview was held for Government officials, Congressional staff, and

members of the press. (Seep. 24.)

25
Scatter Radar: Space Research from the Ground, a 23-minute, 16mm color

movie, was released during the year. The picture tells the story of the

Jicamarca Observatory, new NBS facility near Lima, Peru. Jicamarca,

largest installation of its kind in the world, utilizes a 22-acre radar antenna.

It probes the upper atmosphere to measure electron densities, has already

made observations of the planet Venus, and will study the solar corona and

solar gases.

On May 11, 1963, the NBS Washington laboratories were opened to the

public for the first time in many years. The open house program was a part

of the celebration of the 60th anniversary of the Department of Commerce.

Approximately 7,000 persons visited during the day and went on selected

tours among the more than 100 laboratories and special exhibits that were

open for public inspection. At the NBS Boulder, Colo., laboratories, the

anniversary was also commemorated by special tours and open houses for

high-school students and the general public.

During the year, the Bureau participated in 18 scientific and technological

exhibitions, with exhibits depicting the Bureau's research programs. Featured in several of these exhibits was a working model of the NBS ultrasonic

thermometer, operating at liquid helium temperatures. Typical of the year's

shows were National Academy of Sciences, Washington, D.C.; International

Symposium on Humidity and Moisture, Washington, D.C. ; Northeast Commerce and Industry Exposition, Boston, Mass.; National Electronics Conference, Chicago, 111.; and National Scale Men's Technical Conference and

Exhibit, Cleveland, Ohio.

The Bureau's motion picture program included 3,694 showings of NBS

films to a total audience of 434,359, 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 3.1 in numerical order. A

review of selected research and development programs is presented in this

section under headings corresponding generally to these organization 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 provide a central basis for a system of physical measurement by maintaining, developing, and disseminating standards for commonly used physical quantities such as length, mass,

26
volume, density, and angle, as well as for light, color, electromagnetic radiation, and other optical and photographic quantities.

With the assistance of the Advanced Research Projects Agency, work on

the thermal and optical properties of materials was expanded during the year

to include measurements of the optical properties of infrared-transmitting

materials. Research is in progress on the measurement of the transmissivity,

reflectivity, emissivity, homogeneity, and scattering properties of materials

widely used in space, industrial, and research applications.

The calibration program has been strengthened by the use of automatic

measuring and computing equipment, particularly in the calibration of mass

standards. The resulting savings in human labor formerly required permitted the Bureau to offer new calibration services with less delay and to devote more effort to the development of improved measuring systems and

standards.

A New Standard of Spectral Irradiance. The accurate measurement

of spectral irradiance has assumed increasing importance in connection with

studies of the irradiance to which space vehicles will be subjected. The

making of such measurements was facilitated by the development of a new

standard of spectral irradiance, a 200-watt quartz-iodine lamp with a coiledcoil tungsten filament operating at about 3000 °K. The lamp is obtained

from a commercial source and is calibrated in microwatts per square centimeter of receiver per nanometer of waveband pass over the spectral range

of 0.25 to 2.6 microns (jj.) . Unlike the standards of electrical radiance

which have been available for several years, the lamp is used without auxiliary optics and, because of its small physical size and high operating

temperature, it provides relatively high spectral irradiances.

Basis for Color Measurement Amended. Since 1931 the international basis for color measurement has been the color-matching functions

for the average normal eye as derived statistically from measurements made

by a large number of observers. These functions were obtained from observations made of visual fields subtending 2 degrees at the eye and they give

satisfactory predictions for field sizes between 1 and 4 degrees. However,

industrial inspections of many products such as paints, papers, plastics,

ceramics, and textiles are customarily made by checking a large specimen

(that is, a visual field subtending 10 degrees or more) against an equally

large color standard, because smaller color differences are detectable this

way. But the color matches thus set up often fail to hold for the same samples viewed at a distance. This apparent discrepancy results from the fact

that the central part of the normal eye is covered by a spot of yellowish

pigment.

In 1957 the International Commission on Illumination requested the Bureau to derive a set of color-matching functions for the 10-degree field from

observations of such fields made by a number of observers at the National

Physical Laboratory in Teddington, England, and at the State Optical Institute in Leningrad, Russia. The derivation was completed in 1959 and the

resulting functions were subjected to intensive practical trials in Canada,

27
Great Britain, Russia, and Spain, as well as in this country. At the 1963

meeting of the Committee of Experts on Colorimetry of the International

Commission on Illumination in Vienna, Austria, these functions were rec- ommended for use in color measurement as a supplement to the 1931

functions.

Calibration of Flashtubes. The use of flashtubes (strobelights) is becoming increasingly important for both terrestrial and extraterrestrial signalling purposes; hence, evaluation of the flux produced by a flashtube in

terms of its effect on the human eye is required. Accordingly, the Bureau

recently undertook the calibration of flashtubes, reporting either the candleseconds per flash in a specified direction or the lumen-seconds per flash, as

required. Both the flashtube and its associated power supply are submitted

for calibration, together with a triggering mechanism which triggers the

flashtube repetitively at a stable rate of about one or two flashes per second.

Fluorescent Lamp Measurements Intercompared. The Bureau

recently participated in the first international intercomparison of photometric

and colorimetric measurements on fluorescent lamps with the national laboratories of seven other countries. Three 40-watt fluorescent lamps of each

of three different colors were supplied by the British National Physical Laboratory to the participating laboratories. Laboratory measurements made

of total light output (luminous flux) covered a spread of about 4 percent,

with the individual results varying from —2.4 to +1.5 percent from the

world mean. The NBS value was —0.8 percent from the mean. Although

the variance in the results was not deemed exorbitant, the International Commission on Illumination requested the International Bureau of Weights and

Measures to take steps to narrow the spread.

Color measurement results were more divergent and seemed to depend

on whether visual matching or spectroradiometry was used. The Bureau

values obtained by means of a colorimeter (calibrated with fluorescent lamps

that had been calibrated visually by incandescent lamps and colored filters) were in good agreement with the world mean. However, Bureau chromaticity

results derived from spectroradiometric data were in poorer agreement.

Spectroradiometric results obtained by U.S. lamp manufacturers were compared and were also found to contain substantial differences. Consequently,

since the international goal is to place the colorimetry of fluorescent lamps

on an objective basis that is dependent upon spectroradiometric data, an investigation of the whole problem of data reproducibility is being

undertaken.

Equipment Developed for Calibrating Thermal Detectors. A

new standard "blackbody" detector and a filter spectroradiometer for use

in the calibration of thermal detectors were developed. The detector consists of an inside-blackened gold-foil conical receiver to which is attached

a series of thermocouples. It has a spectral emissivity of 0.99 or more

throughout the spectrum from the short ultraviolet to the long infrared. The

filter spectroradiometer consists of narrow-band interference and other

glass filters, and mercury line sources, tungsten lamps, and globar radiators.

28
During a calibration, the sources with the filters produce spectrally homogeneous lines and narrow bands at some twenty wavelengths between 0.25 and

20 fi to successively irradiate uniformly over their entire surfaces the new

standard detector and the detector under test. The relative spectral response

of the test detector is thus measured as the ratio of the two responses as a function of wavelength. All commercial thermal detectors measured so far

vary in response with wavelength by 5 percent or more. However, their cali- bration permits their use in precise radiometric investigations.

Equipment Developed for Densitometric Calibrations. A quantitative method of photometric attenuation was developed for densitometric

calibrations. A rectangular aperture fitted with a sliding straight-edged

shutter is employed. Light flux through the aperture is made proportional

to the open aperture area by a compensating procedure, as follows: When a

thin slit is moved across the aperture, the light passing through the slit to a detector is compared to the light coming from the same source by a different path. If the response of the detector is constant as the slit moves, the

shutter is replaced, and the flux through the aperture to the detector is then

known to be proportional to shutter displacement, which can be measured

precisely. If detector response is not constant, the aperture edges may be

shaped or an optical compensator may be placed in the aperture to produce

Measuring the refractive indices of synthetic calcium fluoride. Such values

provide a basis for selecting optimum crystalline materials for the design of

optical components and systems. (Seep. 30.)

29
the required condition. Two slits may be used to establish an exponential

or inverse square relationship to the shutter displacement if desired. The

method requires about one-tenth the space required by the inverse-square

method now in use, and it is less subject to certain errors. Its applicability to

the calibration of photographic-density step tablets was confirmed experimentally and the equipment is being refined.

Refractive Index of Calcium Fluoride. The increasing use of cal- cium fluoride for infrared and ultraviolet optical devices, particularly in

military detection and guidance systems, suggested the use of synthetic

calcium fluoride—which has been available for several years—for such

applications. However, the refractive index of the synthetic material, which

must be carefully considered in the design of such devices, was known for

only the visible region of the spectrum. The Bureau therefore measured the

refractive index of both a synthetic and a natural crystal of calcium fluoride over a wavelength range from 0.23 p. in the ultraviolet to 9.7 fi in the infrared.

Results indicate that synthetic crystals, when properly prepared, are comparable in refractive properties to natural crystals.

Generalized Lens-Bending Procedure Developed. A tool often

used by the optical designer is the well-known procedure of bending a lens

element; that is, varying the curvatures of both of its refracting surfaces by

some common increment. The increment is an independent variable, while

the two curvatures of the lens system represent parameters dependent on it for their modified values. A family of lens elements is thus defined, each

member of which possesses useful properties in common with the original

lens element. When this element is a thin lens for which the refractive

indices are the same on both sides, the paths of the marginal and prinr.inol

paraxial rays are left invariant over the remainder of the lens system.

A generalized lens-bending procedure recently developed for the case

of thick lenses and unrestricted refractive indices possesses this same invari- ance property with respect to the path of the two paraxial rays. The procedure required variation (by unequal amounts) of the curvatures of the usual

two surfaces, together with related variations of two vertex separations. Indices of refraction are not modified. Thus, variation of four lens parameters

is obtained as a function of the independent variable which specifies the

amount of "bending" desired. The chief advantage of generalized bending

is that it allows variation of third-order aberrations arising from a single

element of a lens system, independently of the remainder of the system.

Technique for Deriving Principal Curvatures of Wave Fronts.

A mathematical technique was recently developed for determining the principal curvatures of a refracted or reflected wave front in an optical system.

The technique extends geometrical analysis beyond traditional ray tracing

for a large class of optical systems. Since the amplitude of the electromagnetic wave associated with the wave front is inversely proportional to its Gaussian curvature, the technique is useful in any attempt to describe quantitatively the physics of light propagation in lenses.

30

I
Images, photographed at various focal planes on the lens axis, formed by placing

a perforated plate on the front surface of a long focal length lens and illuminating it with collimated light. These "spot diagrams" aid in the determination

of the geometrical properties of the lens. (A) taken on the lens side of the

position of best focus; (B) taken at the position of best focus; (C) taken beyond the position of best focus. (See p. 30.)

An immediate application was found for the results of this work in a study of designs for grating spectrometers. Long-range applications are

anticipated in the area of physical optics. A computer program was prepared to obtain automatically processed data for required calculations.

Image Evaluation. In an image evaluation program on photographic

objectives, work is in progress on the effects of known defects (such as

striae, bubbles, feathers, streaks, and surface scratches) in objective lenses on limit of resolution, wave front shape, frequency response, and general

picture quality. Five lens samples are being observed, supposedly differing

only in the glass from which they were made. A lens of good glass quality

is included in the group as a control.

Measurement of Wave Fronts. A method was developed which permits the measurement of the departure of the wave front emergent

from a lens from a true spherical wave front in terms of wavelength. The

method involves the measurement of the displacements of the central fringe

of an interference pattern. The pattern is produced by the introduction of a double slit into the beam of light incident upon the lens. Measurable displacements of the pattern occur as the double slit moves across the front

of the lens. An accuracy of ±0.02 wavelenth is attained.

Stored Microfilms Inspected. As part of a study of the permanence

of photographic materials, large numbers of microfilms of Government

records were inspected. The inspections revealed a rather widespread in- cidence of microscopic defects after 2 to 20 years of storage. These defects,

confined almost exclusively to negative microfilm, are circular reddish spots

from 15 to 150 /x in diameter, some having a concentric ring structure, or a decrease in density and general broadening of printed lines and other

information. Practically no information loss was observed, but the necessity

of periodic inspections was made clear. Microcopy Chart Designed. In response to demands of science and

industry, a microcopy resolution test chart was designed. When proposed

minor amendments are made in existing microcopying specifications, the

new chart will replace the current NBS Standard Sample No. 1010. Chart

31
color, line type, contrast, line-to-space ratio, number of lines per group,

and length-to-width ratio of lines conform to current specifications. Very

small changes were made in a few spatial frequencies to make the series

conform to an international standard preferred-number series. A slight

alteration in the layout of the patterns permits the frequency range to be

extended to higher or lower frequencies and permits the chart to be abridged

conveniently when desired. A small change in the size of the sheet will have no effect upon the usefulness of the chart but will accomplish considerable

economies in time and materials in chart production.

Method Developed for Measuring Thiosulfate in Processed Film.

A new analytical procedure for measuring the thiosulfate radical remaining

in photographic film after processing was developed. Such measurements

are routinely done at the Bureau to ascertain conformance to microfilming

specifications which require that films be sufficiently well washed to reduce

thiosulfate concentration to less than 0.005 mg per square inch (reported

as sodium thiosulfate) . The current standard analytical method has been

in use for the past 30 years. The new procedure, which is based on the same chemical principles, reveals two to three times as much residual thiosulfate as does the current standard procedure. A new method of measuring the residual non-image silver in processed film was also developed.

Length Measurement Research. Ultra-precise methods for making

length measurements are being sought so that length standards may be

calibrated to an accuracy approaching a tenth of a microinch. Toward

this end, an ellipsometer was acquired to determine the thickness of the

thin film existing between joined gage blocks. In application, these films are an inherent part of the length of end standards of length. To aid in

this research, a theory was developed on the behavior of light beyond a surface normally thought to be totally reflective.

Thermal Expansion Measurement Capability Extended. Additional data are needed on the thermal expansion of materials in the extreme

environmental conditions of outer space and in the thrust nozzles and heat

shields of space vehicles. So equipment designed to increase Bureau meas- urement capability from 1000 to 1700 °C was installed and operated thus

far at temperatures above 1600 °C. Cryogenic equipment was also designed and is now under construction. This equipment will extend the

Bureau's minimum temperature range capability to —250 °C.

Wave-Front-Shearing Interferometer. A wave-front-shearing interferometer was developed and applied to the testing of mirrors and lenses.

In one study, it was placed at the focus of a 26-in. refractor at the University of Virginia, in probably the first interferometer test of an astro- nomical telescopic in situ. Four photographs of interference fringes were

obtained by changing the direction of shear 90° between each photographic

operation. The shape of the wave front as it emerged from the objective

could then be computed. By way of further development, a means was

devised for rotating the fringes into the direction which would provide the

best accuracy.

32
Screw Thread Standardization. Thorough consideration was given

by the American Standards, Association's Sectional Committee Bl, the Inter- departmental Screw Thread Committee, and a recent American-BritishCanadian Conference on Engineering Standards to the revision of the definitions of pitch, groove, ridge, and functional diameters of screw threads.

The revisions were correlated with types of limit gages and measuring methods to clarify a dimensional control problem. The new concepts developed

will be published in revisions of Nomenclature, Definitions, and Letter Symbols (Section II of NBS Handbook H28), and American Standard

B1.7.

In other studies, a critical review was made of the factors which affect

the accuracy of pitch (or groove) diameter measurements by the use of

thread wires, and proposed revisions in standard measuring practice were

developed. The revisions will provide optimum compensation of elastic

deformations under measuring forces and will prevent excessive compressive

stresses which would cause permanent deformations.

Laser Produces Fringes Over 200-Meter Path. Improvements in

the design of a helium-neon laser permitted its output to be operated at a

single mode (the highly monochromatic portion of a single spectrum line)

It was found that a quartz spacer tube maintained constant spacing of the

instrument's end reflecting plates and thus the stability of laser frequency.

In recent work with the laser, its infrared light of wavelength 11,530 A

applied to a modified Michelson-type interferometer produced fringes that were first converted to visible wavelengths and then observed and photographed over a 200-meter optical path.

Cockpit Lighting in TFX Aircraft. Advisory services, provided by

the Bureau to Navy, Air Force, and General Dynamics Corporation engineering personnel, led to standardization of the color of illumination for the cockpit lighting of TFX (F-lll) aircraft, and to the first specified use of electroluminescent sources for cockpit lighting in an American plane. The standardization will result in monetary savings in the production of this plane.

Accuracy of Spectral Transmittance Standards Investigated. For

a number of years the Bureau has been issuing glass filters (selenium red,

carbon yellow, copper green, and cobalt blue) for use as spectral transmittance

standards in checking the photometric scale of spectrophotometers throughout

the visible spectrum. The NBS reference standards used to calibrate these

filters are periodically evaluated at the Bureau to determine their true spectral

transmittance values. However, the results of two recent recalibrations of a set of the issued filters suggested a possible drift in the spectral transmittance

values of the NBS standards. An extensive recalibration was therefore

undertaken of the latter. The measurements obtained showed that the values

of spectral transmittance at some wavelengths differed slightly from previously

assigned values but not by amounts exceeding the combined uncertainties of

former calibrations and the present recalibration.

33
Measurement of reflective properties of materials used for balloon satellites. The measurements will provide a basis for analysis of the effect of radiation

pressure on such satellites. (See p. 34.)

Goniophotometry. To assist the National Aeronautics and Space Administration with an analysis of the effect of radiation pressure on a balloon

satellite, goniophotometric measurements were made on plane specimens of

the skin at a large number of angles of incidence and viewing. The results were reported in terms of the intensity factor, that is, the ratio of radiant

intensity to incident flux. The data were obtained with a manual point-bypoint goniophotometer. Subsequently, the Bureau received delivery of a custom-built recording monoplane goniophotometer. The new instrument

will greatly facilitate goniophotometric investigations of reflected and trans- mitted flux distributions from all kinds of materials.

2.1.2. MECHANICS

The Bureau's work in mechanics is primarily concerned with the development and improvement of measurement methods for mechanical phenomena

in solids, liquids, and gases; the establishment of required standards in

mechanics and the relation of such standards to prototype standards; the

support of these activities by theoretical and experimental research on

mechanical phenomena; the determination of physical constants of particular

importance in mechanics; and provision of assistance to other laboratories

in relating their measurements to a common basis (or to established standards) 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.

34
These measurement areas are of importance to scientific and engineering

programs (including those of the space effort) which require great accuracies over wide ranges under extreme temperature environments. Special emphasis is therefore given to research directed toward meeting these needs.

The design of special-purpose equipment to be installed in the Engineering

Mechanics Laboratory at Gaithersburg, Md., was completed. This equipment includes deadweight testing machines of 113,000-lb, 300,000-lb, and

1,000,000-lb capacity and a universal testing machine of 12,000,000-lb capacity. Design work progressed on two other laboratories, one for sound

experiments and the other for fluid mechanics research. When these three

facilities are in operation, it will be possible to provide improved services in

several of the measurement areas in mechanics.

Vibration Amplitudes Measured. The range of amplitudes over which vibration-measuring instruments can be calibrated photometrically

with a Fizeau optical interferometer was extended by the development of a method to replace the human observer method previously used. The new

method covers amplitudes from 1090 angstroms (A) up to about 1 micron

(about 4 to 40 microinches) and the entire range of audiofrequencies up to 20,000 cycles per second (c/s), in contrast to the amplitude range of the

old method of from 72 to 4400 A.

A unique feature of the new method is the vibration of both plates of the

interferometer, one at a modulating frequency much lower than the calibrating frequency of the other. The resulting modulated light flux is detected

by a photomultiplier. The photomultiplier signal is analyzed electronically so that a meter shows a sharp null when the amplitude of vibration of the

plate, moving with the vibration pickup attached to it, reaches one of a number of accurately known values determined by the optical wavelength.

This method improves the precision of Bureau calibrations and reduces the

time required to perform them.

Microphone Calibration. Pressure calibrations of condenser microphones are usually carried out in small hydrogen-filled couplers at ambient

barometric pressure. During the past year, an apparatus was developed

which prevents excessive loss of hydrogen from the coupler for long periods

of time. This apparatus connects the coupler's capillary tubes to relatively

large containers of hydrogen and vents the containers to the atmosphere

through additional capillary tubes. The system provides ample time for

performing reciprocity calibrations accurately in the three cubic centimeter

couplers that are used over a frequency range from 500 to 20,000 c/s.

Portable Tube Designed for Sound-Absorption Measurements.

A portable acoustical impedance tube was developed as an instrument for

practical research on sound-absorbent materials. The tube makes precision

measurements of impedance and sound absorption in both laboratory and

field installations, over the frequency range from 400 to 900 c/s. It is useful

for the development, manufacturing control, and acceptance testing of acoustical materials installed in various buildings, as well as for the determination

of aging, staining, and redecoration effects on sound absorption.

35
Cavitation Data Obtained. Cavitation, or the opening up of cavities

in liquids subjected to tension, has been intensively studied for years.

Hydraulic cavitation, such as that occurring on and about ship propellers,

is of great practical importance since it wastes power and damages propeller

blades. Another type is sonic cavitation, in which tension occurs during

the rarefaction phase of an intense sound wave. This effect is commercially

important in sonic processing.

A fundamental problem in sonic cavitation is the origin of the nuclei, which

are very small air-filled or vapor-filled cavities. Theory indicates that they

must preexist in order for catastrophic expansion to take place at the levels

of tension (cavitation threshold) observed. Workers abroad report evidence

that nucleation is primarily induced by secondary neutrons connected with

cosmic radiation. Independent experiments along these lines are under way

at the Bureau, jointly sponsored by the Office of Naval Research.

Cavitation thresholds are notoriously irregular, and quantities of data are needed on these thresholds for statistical processing; however, an inordinate

amount of labor is involved. So in the current Bureau study, a device which

automatically measures and records the cavitation threshold of a sample of

water 100 times a day was developed. After automatic processing of these

data by an electronic computer, it may be possible to separate the effects of

the numerous variables involved and thus obtain additional evidence on the

nucleation process.

Measurement of Impact Sound Transmission in Buildings. A

comprehensive study was undertaken during the year to develop a standard

test method for the measurement of impact sound transmission. In this study,

in which three other laboratories participated, a roundrobin series of impact

tests with a standard tapping machine was conducted on basic 4-in. -thick

concrete floor specimens. The specimens were subsequently surfaced with

acoustical materials and again tested. Field measurements on floor struc- tures nominally identical to those measured in the interlaboratory program

are currently in progress to determine the correlation that exists between

laboratory and field measurements.

This study, jointly sponsored by the Army, Navy, and Air Force, was

closely coordinated with work of the Federal Housing Administration, which

recently developed the first impact-noise criteria for use in this country. The

criteria, based in part on NBS laboratory measurements, were recently published as FHA Report No. 750, "Impact Noise Control in Multi-Family

Dwellings." This document is a clear and concise guide for the control of

impact noise, and it is designed for use by the FHA insurance staff as well

as by architects and builders.

Infrasonic Waves Studied in the Atmosphere and in the Earth.

Preliminary comparisons of sound waves received at the Bureau's new in- frasonics station in Boulder, Colo., and at the station in Washington, D.C.,

reveal a number of time intervals in which signals were recorded from the

same source in a distant geographical area. Comparisons of arrival directions at the two stations now being made will allow some fairly precise deter36
Measurement of impact noise produced on floors by footfalls. The sound is transmitted through the floor and measured in the room below. Results produced in this way are being compared with measurements of noise from the

standard tapping machine usually used in laboratory work. Sound measure- ment is an important step in the formulation of sound insulation requirements

in building codes. (See p. 36.)

minations of the geographical areas from which signals are generated by

ionospheric disturbances, tornadic storms, volcanoes, and by presently

unknown sources. Observations with a temporary infrasonics station at Fort Yukon, Alaska,

confirmed that infrasonic waves, previously associated with geomagnetic

activity from measurements at the Washington, D.C., station, were caused

by auroral disturbances. Comparison with geomagnetic fluctuations and

cosmic radio noise absorption effects indicated an atmospheric pressure wave

source intimately connected with the behavior of the auroral ionosphere.

The temporal and geographical distribution of the ionospheric disturbances

are controlled by the position of the sun and the level of solar activity.

Further observations on infrasonic waves (having periods of about 6

seconds), commonly called microbaroms, confirm the hypothesis of their

oceanic source. The ocean waves periodically arriving on the eastern sea- board can radiate enough sound to cause microbaroms to be observed at Washington. They are present also at Boulder, but substantially weaker

because of the greater distance from the coasts of North America.

Infrasonic waves radiated by tornadoes in the midwest continue to be

received at the Washington station. They are also observed at the Boulder

station and at the Boston station of the Air Force Cambridge Research Laboratories. Such waves have periods longer than 10 seconds. (Other aspects

of this study are discussed in 2.3.4, Geomagnetic Micropulsations and Infrasonic Pressure Waves, page 146.)

37
Three seismometers of a type developed at the Bureau were installed at sites

several kilometers apart in the Washington area. A telemetry system has

been worked out so that seismic vibrations are simultaneously recorded at the

Bureau. The seismometer system is now being used to determine the speed

and direction of microseisms, having periods near 6 seconds, propagated

through the Washington area. The possibility of a common origin for both

microbaroms and microseisms is being investigated.

Audiometry Research. People usually hear by sound waves which

travel down the ear canal to the eardrum (air conduction), but sounds can

also be heard when a vibrator is applied to the bones of the head (bone con- duction). The least sound that can be heard is called the threshold, and a knowledge of its level is important in the medical diagnosis of impaired hearing. Also of importance are the relative levels of the air-conduction and boneconduction thresholds.

Air-conduction thresholds measured on 12 young otologically normal

persons were used to determine the maximal displacement amplitudes of the

basilar membrane in the inner ear. Bone-conduction thresholds in terms

of vibratory displacement of the skull, measured on the same group, were

related to the displacements of the basilar membrane. These data were then

used to determine vibratory motion transmission characteristics for the

mastoid and forehead bones. Data obtained on the mechanical impedances

of the head bones for the same persons were combined with the threshold

displacements to obtain basic information on the vibratory power required

for hearing by bone conduction.

Data on the threshold of hearing by air conduction are best stored as sound

pressures produced at various frequencies by an earphone placed on a

coupler. The coupler contains a small volume of air and a microphone for

measurement of the sound. Such a coupler was developed years ago at the

Bureau as a standard for audiometric measurement. The technical committee on electroacoustics of the International Electrotechnical Commission

recently decided that this coupler was suitable for storage of threshold data

newly adoped by the International Standards Organization. The committee

will therefore issue a report describing the coupler to facilitate international use of standard thresholds in audiometry.

Improvements Sought in Pressure and Vacuum Measurements.

The range of pressures (from 10~15 millimeters of mercury to 50,000,000 psi)

of interest in science and industry is so vast that many different types of in- struments and techniques are required. Efforts are being made at the Bureau

to extend pressure-measurement capability by improvements in the design

and construction of apparatus, and to develop better experimental techniques.

In the range of high-pressure measurement, the freezing pressure of mercury at 0 °C was determined to be 109,722 psi with an accuracy of ±30 psi.

This pressure fixed point is adequate as a calibration point to serve current

needs. The mercury experiment verified the advantage of a manganin re- sistance pressure gage as a working pressure gage. The full potential of

manganin gages has not been realized, so the electrical system for pressure

38
measurements is being improved in order that more detailed study may be

made of the pressure-temperature-resistance characteristics of manganin.

A new piston gage is under construction for use in a more accurate determination of the phase transition of bismuth between 365,000 and 370,000

psi. This transition has served as the principal calibration point for the

ultra-high-pressure range. Work has continued on the "two-stage" modification of a tetrahedral apparatus in which stishovite, a form of quartz, has

been produced at a pressure of 2,000,000 psi and a temperature above

3000 °F.

Studies in vacuum measurement were continued in the search for force-perunit-area techniques as contrasted to the indirect methods usually employed

in the field. Such techniques are needed to increase the accuracy of conventional vacuum measurements. A detailed study of capillarity effects on the

widely used McLeod gage is being carried out. Volume expansion of a fixed

quantity of gas was used to study McLeod and ion gage characteristics.

Preliminary experiments on an interferometer—oil-manometer led to the

design of an improved model which is now nearing completion.

Computer Techniques Applied in Turbulence Studies. In col- laboration with the David Taylor Model Basin, a digital computer technique

is being applied to the measurement of the statistical properties of turbulence.

Thus far, probability distribution, time, space, and space-time correlations

in an isotropic turbulence field have been measured. The results demonstrate

the feasibility of applying such methods to the measurement of turbulence

and provide extensive information as to the space-time transformation and

higher order correlations.

Correlation measurements up to the eighth order were obtained by the

computer technique, representing a significant step beyond the fourth-order

correlations previously derived by conventional analog methods. The computer application to the measurement of other pertinent quantities such as

derivatives, higher orders thereof, and joint probability distributions will

be investigated.

Boundary Layer Instability and Effect of Roughness. Due to the

instability of fluid laminar flow in a thin layer near a wall, known as the

boundary layer, ensuing turbulent motions completely alter the characteristics

of the flow. It is known that instability gives rise to selective amplification

of initially small disturbances and that the end result of the process is a breakdown of the flow to the turbulent state. In a program sponsored by the

National Aeronautics and Space Administration, the manner in which turbulent motions begin as the result of an instability has been under investigation

for some time.

In the investigation, the breakdown process was traced by means of sensitive hot-wire probes through its various stages. This technique revealed that

before the motions become turbulent and while they are still wavelike in

character they become three-dimensional. In doing so, they modify the flow

at certain localities along the wave train and give rise to a second type of

instability—the so-called inflectional instability—from which final breakdown

ensues.

714-691 0—64 4 39
When a wall is not smooth, the roughness elements usually cause or promote

transition to turbulent flow. While empirical rules for this effect have been

established, the mechanism involved has in general remained obscure. The

present study has, however, revealed the mechanism involved when the roughness is a single, two-dimensional element commonly called a trip wire.

Systematic measurements showed that this type of roughness element promotes

transition by destabilizing a region of modified flow downstream from the

element. In this more unstable flow field, selective amplification of ambient

disturbances is increased. The observed amplifications are in line with

existing stability theory.

Standards Designed for Million-Pound Forces. As a part of a program to support the Nation's efforts in space, the Bureau is constructing

a series of deadweight force machines in ranges up to one million pounds at

its new laboratories now being built near Gaithersburg, Md. The continued

accuracy of these machines is being assured by the acquisition of a set of

three reference standards of mass made of stainless steel in units of 10,000,

20,000, and 30,000 pounds. These weights, the largest ever constructed to meet Bureau requirements, have been adjusted to an accuracy of one-thouTen-, twenty-, and thirty-thousand pound mass standards compared to a one- kilogram mass. These weights, the largest ever constructed to meet NBS Class

C requirements, will be used in the deadweight force machines now under construction at the new Gaithersburg laboratories. (See p. 40.)

40
sandth of one percent. A precision scale, having a capacity of 30 tons and

sensitive to a variation of 2 ounces, will permit comparison of the working

weights of the deadweight machines against the reference standards.

Compact Precision Centrifuge Constructed. A centrifuge with a

36-in.-diameter table was designed and constructed to calibrate precision

accelerometers over an acceleration range from 1 to 80 g with errors that

do not exceed 0.1 percent. For calibration of servoaccelerometers, accurate

knowledge of the location of the seismic mass is important. This location

may be determined by indirect means as a function of the output signal.

Rheological Constitutive Equations. A special constitutive equation

has been found adequate to explain stress relaxation data for a variety of

polymeric materials in simple uniaxial extension over a wide range of

extension ratios. Discrepancies appear, however, when this equation is applied to equilibrium data on biaxial extensions. In an effort to develop

a more comprehensive expression which will account for the biaxial meas- urements as well as for the uniaxial ones, a new theory of incompressible

elastic materials was developed. This theory is more general than the usual ones in that it allows an isotropic pressure to affect the shear. Experiments on simple extension of rubber strips under varying isotropic pressure indi- cate that the new theory is indeed germane. Further studies are in progress to determine whether it will eliminate discrepancies in biaxial data.

In a related study, a test was made of a conjecture originally advanced by

Weissenberg on the equality of certain normal stress components in elastic

fluids. This was a qualitative test to see if direct evidence could be found

by a search for streaming in cross-sectional planes in a fluid flowing through

a pipe of rectangular cross section. The observations showed that the flow

through certain regions of the pipe followed a spiral rather than a straight

line. This evidence indicates that the Weissenberg conjecture does not

hold, a conclusion also reached by Markovitz at Mellon Institute recently on the basis of certain quantitative measurements of normal stress. Review of Volume Relaxations in Polymers. A survey of experimental data on volume (dilatational) relaxations in amorphous polymers was completed. The survey was concerned with the time scale or frequency

of measurement as related to temperature and static pressure. For natural

rubber and poly (vinyl acetate) there are reasonably complete measurements,

principally those made at the Bureau of the dynamic bulk modulus. For

other polymers the data are incomplete and often fragmentary. From the

data available, however, certain generalizations may be made with a reasonable degree of confidence.

Dilatational relaxations are apparently found in all amorphous polymeric systems. The effects of temperature and pressure are qualitatively

the same on the relaxation times associated with dilatation as they are on those associated with shearing motions. In some cases these effects are not only similar but are quantitatively identical, indicating in these

cases that the same molecular motions excited by a shearing force are excited

by a pressure.

41
The data suggest that this identity holds in cases where the molecular

motions involved are solely cooperative motions of segments of the main

chain. The maximum number of segments participating in cooperative

motions in response to a pressure is very much smaller than the maximum

number involved in response to a shear force. This conclusion is supported

by the fact that the relaxation spectrum for dilatation extends over a smaller

range of time than does the relaxation spectrum for shear.

Hypersonic Combustion. Research was continued on the properties

of detonation waves stabilized on a hypervelocity missile in a stationary combustible gas. Wave structure in hydrogen and air was derived on the basis

that a bimolecular reaction controls the rate of heat release behind the shock

frdnt. Effect of heat release in the flow field on wave shape and position was

derived by a graphical and numerical integration of the equations of motion

of the gas between the wave front and missile. The reaction rate constant was adjusted to yield equality of computed and observed wave shape and position over a range of pressures and Mach numbers. Thickness of the detonation wave was derived to be about 104 mean free paths in the shocked gas. Experimental observations of wave shape and position were also made in pentane-air and methane-air mixtures.

Two kinds of unstable combustion were observed in these experiments

and in previous experiments with hydrogen. In one kind, the period of the

oscillations was proportional to ignition delay time, suggesting an intermittent combustion at the front of the missile. The second kind was apparently an acoustic oscillation with period proportional to the sound wave transit

time between the shock and combustion wave fronts.

Reference Fuel Control Test Facilities Operated at the Bureau.

Fuel controls are extremely complicated mechanisms used to control and meter

automatically the fuel flow into gas-turbine aircraft engines under all conditions of flight. These units require extensive adjustment and test prior to

installation to assure optimum aircraft performance. Necessary prerequisites

for the satisfactory adjustment of such units are a high degree of absolute

accuracy in fuel control test benches and standardized test procedures.

The Bureau of Naval Weapons maintains reference fuel control test facilities at the Bureau with which similar equipment used by industry and the

military services may be checked for accuracy. In a typical program, refer- ence fuel controls are calibrated at the fuel control manufacturer plant, at the engine manufacturer, and at the Bureau, and standardized test procedures

are agreed upon. After good accuracy agreement is obtained between the

Bureau and industry, the calibrated fuel controls are sent to naval overhaul

stations for accuracy checks of Navy equipment.

The fuel control systems for nearly every model of aviation gas-turbine

in operation in this country have been given these reference tests at the

Bureau. As new engines and new model fuel controls are placed in service

at the rate of about three each year, they are also included in this reference

correlation program.

42
Static Electric Failure of Aircraft Engine Fuel Hose. Hoses containing an inner core of rubber or other suitable material and an outer

covering of woven wire mesh are used extensively to interconnect the various

fuel system components of internal combustion engines. Improved hoses,

containing an inner core of a relatively nonconductive thermoplastic fluorocarbon were developed recently for high-temperature operating conditions.

Many of these failed in service, however, as a result of the generation and

discharge of static electricity produced by the flowing fuel. Under the sponsorship of the Bureau of Naval Weapons, this phenomenon

is under investigation. Results up to the present time show that very high

electric potentials are produced when a nonconductive liquid flows within a nonconductive tube or pipe. The potentials are sufficient to produce electric arcs or sparks several inches long within the tubing. Also, these arcs penetrate through the walls of the tubing, resulting in pinhole punctures. Investigations are continuing to determine the influence of the properties of the fuel on the generation of static electricity, the maximum rate of charge that may

be anticipated under operating conditions, and the desired level of tube

conductivity by which such charges may be conducted safely to the ground.

Electrical spark discharges caused by the flow of a hydrocarbon liquid through

a nonconductive plastic hose. The Bureau is conducting a study aimed at eliminating service failures in engine fuel lines which occur when the discharges

puncture the line. (See p. 43.)

Reference Tables for a New Thermocouple To Be Established.

Platinel n thermocouples, because of their good stability at intermediate

temperatures, are rapidly gaining acceptance, particularly in the aircraft

industry where base-metal thermocouples, due to exposure to oxidizing hightemperatures gases, are relatively short-lived. Because of this growing ac- ceptance, the Bureau has undertaken to establish reference tables for Platinel

II. These tables will be determined from observations on 27 separate thermo43
couples: nine thermocouples from each of three separate melts of materials.

Each group of nine will consist of three each of 20-, 30-, and 40-mil wire.

Concurrently, work is continuing on stability studies in oxidizing atmospheres. It was found that Platinel II is relatively stable at temperatures up

to about 2200 °F.

Flame Speed Inhibitors. Study of the effects of halogenated hydrocarbons on the flame speed of methane was continued. Halogenated hydrocarbons have long been used to extinguish fires, and the effects of these substances on flame speed may possibly be used as a means of testing their

effectiveness. Methyl bromide, methyl chloride, and dichlorofluoromethane were examined as additives to methane-air mixtures, and of these, methyl

bromide was shown to be the most effective in reducing flame speeds. The

reduction of flame speed was found to be proportional to the amount of

additive.

High-Temperature Thermocouples. Reference tables of thermal

electromotive force versus temperature were completed for three iridiumfhodium versus iridium thermocouples in current use. Tables for the 40

percent iridium alloy were published and those for the 50 and 60 percent

iridium alloys up to 3900 °F are ready for publication. Computations are

in progress on the data for 10, 25, 75, and 90 percent rhodium for temperatures up to 4000 °F. It is expected that the optimum composition for an iridium-rhodium versus iridium thermocouple will be derived from the information obtained so far on the seven alloys.

2.1.3. ELECTRICITY

The Bureau's work in electricity is primarily the development, improvement, and dissemination of the standards of measurement for electrical

quantities; and the study of the electrical and magnetic properties of materials. 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 comparison with these electrical standards.

A new section, Absolute Electrical Measurements, was established to separate calibration activity from fundamental measurement research. New procedures for realizing the electrical units via the volt and henry are being

investigated.

Absolute Measurements. A group of portable 10-picofarad capacitors was built. One capacitor of the group was carried to the National

Research Council (NRC) in Canada for comparison of the units of capacitance maintained in the two countries. Since both NRC and the Bureau

obtain their units of capacitance from calculable standards of the ThompsonLampard type, the comparison constituted a check on the accuracy of absolute

44
One of a group of transportable 10-picofarad quartz ca- pacitors built for use in intercomparing NBS capacitance

measurements with those of

other laboratories. One in- tercomparison has already

been made with the National

Research Council of Canada,

and showed that NBS and

NRC measurements differed

by only 2 parts in ten million.

(See p. 45.)

-

capacitance measurements at the two laboratories. The comparison indicated that the capacitance units of the two laboratories differed by about two

parts in ten million. Since the Bureau and NRC claim accuracies of only

two or three parts per million, the agreement is much better than was expected.

Considerable progress was made in the development of an improved cal- culable capacitor. This project is expected to provide a calculable standard

of capacitance accurate to at least one part in ten million.

The inductance analog of the Thompson-Lampard theorem was developed,

and a preliminary study is being made of the practicality of a physical

embodiment.

Continuing studies of the proton precession frequency and the Zeeman

transition frequency indicate a high degree of stability for the ampere, as maintained at the Bureau with standard resistors and standard cells. Magnetic field perturbations in the solenoid used for this work were found responsible for some of the observed measurement fluctuations. A system of

three-dimensional Helmholtz coils was constructed for use in a scheme

expected to greatly reduce these magnetic perturbations.

Impedance of Dry Cells. An extensive study of the impedance characteristics of the most commonly used sizes of Leclanche dry cells and batteries was completed. The impedance was measured by a substitution

method using a Wien bridge. The study covered the frequency range from

50 through 50,000 cycles per second (c/s) to determine changes in the

45
impedance of dry cells due to aging or use. The impedances of dry cells of

different make, size, type, age, or state of charge vary widely, not only at

a particular frequency hut as a function of frequency. In some cases the

impedance tends toward a maximum value at a particular frequency. In

other cases, no maximum value is attained; the impedance increases throughout a decrease in frequency. Open-circuit voltages and flash currents and

electrical capacities of the cells on standard tests were measured throughout

the study to ascertain possible correlations between these parameters and

impedance and residual capacity.

Battery Depolarizers at High Temperatures. To provide basic in- formation on the stability of depolarizers (oxidizing agents) used in primary

cells, studies were made of the thermal decomposition of manganese dioxide,

the depolarizer used in the common dry cell, over the range from 440 to 640 °C. Manganese dioxide decomposes to form manganese sesquioxide

and oxygen; the oxygen pressure varies logarithmically with temperature

and reaches 135 atm at 640 °C. At higher temperatures (850 to 980 °C),

the sesquioxide decomposes to form hausmannite and oxygen, with the oxygen

attaining atmospheric pressure at 980 °C. From the measured dependence

of the oxygen pressure on temperature and the known heat capacities of

manganese dioxide, manganese sesquioxide, hausmannite, and oxygen as a function of temperature, a new value of —228,700 calories was obtained

for the heat of formation of manganese sesquioxide. The data also yielded a new value of 36.8 cal/deg for the entropy of hausmannite at 25 °C.

Zener Diodes as Voltage Standards. Under a broad measurement

program, the Bureau is investigating methods of accurately measuring the

voltages of zener diodes, which are solid-state devices, in terms of saturated

standard cells having electromotive forces known in absolute electrical

units. Attention focused on the opposition method, wherein the diode

voltage is measured in series opposition to that of standard cells with a precision of three to four parts per million. Temperature-compensated

diodes having nominal voltages of 8 volts received the most study. As an

adjunct to the measurement program, the Bureau has for two years been

studying the long-range stability of zener diodes. In general, the stability

is an inherent characteristic of the diode and may be affected by operating

conditions and environment.

Membrane Potentials in Fused Salts. Reference electrodes or ref- erence half-cells for use in electrochemical studies of fused salts are frequently

isolated from the fused salt under study by fused silica or vycor. Apart

from any ionic diffusion that may occur through the silica or vycor, interpretations of the voltages of galvanic cells, including the reference elec- trodes, may be in error as a result of neglect of potentials that may arise

at the silica or vycor membrane. As part of an investigation to ascertain

the magnitude of these potentials, the Bureau studied membrane potentials

of silica and vycor in silver chloride-sodium chloride melts, maintaining

a constant mole fraction of silver chloride on one side of the membrane but

varying it on the other side. When the mole fraction of silver chloride

46
was varied from 100 to 10 mole percent on the variable side of a vycor

membrane, the membrane potentials at 850 °C decreased from 540 to 9

millivolts. Thus, for a silver chloride reference electrode, silver chloride

should be used as a minor constituent in a silver chloride-sodium chloride

melt.

Differential A-C—D-C Transfer Standard. A new a-c-d-c comparator was developed to meet the growing need for more accurate, as well

as more rapid, means for measuring a-c voltages at audio frequencies. The

instrument can be used for the simultaneous comparison of an unknown a-c voltage with a known d-c voltage, eliminating the time lag between successive

comparisons necessary with older forms of a-c-d-c transfer instruments that

sometimes changed during the interval. It is ten times as accurate as an

earlier differential voltmeter, although somewhat less convenient to use. The instrument includes two identical rms voltage-sensing units, with

electrical outputs connected in opposition through a detector. With their

inputs connected to the same power supply, the units are adjusted to equality

of output. They are then connected to the respective external a-c and d-c sources, with appropriate potentiometer and accessories to measure the

adjustable d-c voltage. When equality of output is again obtained, the volt- ages of two sources are equal. Drifts and other changes in the units are self- compensating, so that a usable precision of 10 parts per million (ppm) can

be obtained. The accuracy attainable depends principally on the a-c-d-c

differences of the thermoelement in the a-c unit. Improvements now in

progress in the basic NBS a-c-d-c transfer standards indicate that this differ- ence is very probably less than 10 ppm from 50 to 2000 c/s and 1 to 500

volts, me frequency and voltage ranges in which there is the greatest demand

for high accuracy.

Magnetism. The nuclear magnetic resonance absorption of Ni61 was

observed in 1 percent Ni61-99 percent Fe and 2 percent Ni61-98 percent Fe

solid solutions at 85.4 Mc/s at room temperature. The line width was about

700 kc/s in the 1-percent sample at room temperature, with some broadening

in the 2-percent sample. At 77 °K the resonance occurred at 89.1 Mc/s with

nearly the same line width as at room temperature. The intensity of the resonance signal decreased in an externally applied steady magnetic field. The room temperature hyperfine field at the Ni61 nucleus was 558 kilooersteds (kOe), assuming a nuclear moment of 0.3 nanometer (nm), or 186

kOe, assuming a moment of 0.9 nm. If the hyperfine field at the nickel

nucleus is assumed to be nearly proportional to the local moment, a resonance

frequency of 85.4 Mc/s implies a local atomic magnetic moment of about 2.0

Bohr magnetons at the nickel atom, somewhat less than that in pure iron.

The nuclear magnetic resonance of NiG1 was observed in 1 percent

NiB1-99 percent Co and 2 percent Nicl -98 percent Co alloys. The resonance frequency was found to be 70.4 Mc/s at room temperature and 71.7 Mc/s at 77 °K. The hyperfine field at nickel in cobalt was about two and one-half

times its value in pure nickel, implying a nearly proportional increase in the

47
local magnetic moment. The nuclear moment at Ni61 was determined to be

0.70zt0.04 nm by nuclear resonance studies in steady external magnetic

fields. A permanent adjustable standard of magnetic susceptibility was designed

using the magnetic equivalence of a uniformly polarized volume of paramagnetic material and a solenoid carrying electric current. Such a standard was incorporated into a magnetic susceptibility bridge in a simple manner,

surrounding the specimen; and the bridge was transformed into an absolute

null instrument of high accuracy and sensitivity, and of great ease and low

cost of construction and operation. By this method numerous particular

advantages of other methods were combined, and some of their notable

limitations were overcome. A preliminary application was made showing

that the bridge performs as expected. A detailed consideration of sources of error suggests that it may eventually be possible by this method to obtain

greater absolute accuracy than by other known methods.

An apparatus was constructed for determining absolute magnetic susceptibilities down to liquid helium temperatures by both the Thorpe-Senftle and

the Gouy methods. Measurements were made by both methods on powdered

samples of the same batches of (NH4 ) 2 0sBr6 , HgCo(SCN) 4 , and Fe(NH4 ) 2 (S04 ) 2 -6H2 0. Comparable accuracies were obtained by the two methods;

however, about 3 X 10~2 as much sample was required for a Thorpe-Senftle

measurement.

Magnetic susceptibility measurements were made on a series of hexachloroand hexabromoosmates, M2 0sX6 , and on potassium hexachlororuthenate,

K2 RuCln. The paramagnetism of the Os(iv) complexes is independent of

temperature, and increases as the osmium ions are separated. The magnetic

susceptibility and part of the optical absorption spectrum can be fit to theory

by choosing the values of 2100±100 cm"1 for the spin-orbit coupling constant

and 2800 ±100 cm"1 for the Coulomb interaction coefficient. It is shown

that the effect of dilution is described by the equation x = X°°/ ( 1 + ^~nX

00 ) > where x°o is the susceptibility at infinite dilution, d is the average distance

between the osmium ions, A is a constant, and n is approximately 2. Dielectric Behavior of Liquids and Supercooled Liquids at Elevated Pressures. Apparatus was constructed to study the variation in

dielectric constant and relaxation time of liquids and supercooled liquids at pressures up to 2000 atm. A specially designed thermostat enables the temperature of the dielectric cell to be accurately controlled and continuously

varied from liquid nitrogen temperature ( — 196 °C) to about 50 °C.

The cell incorporates a novel design feature which permits the density of

the material to be determined simultaneously with the dielectric properties.

Thus, by suitable choice of temperature and pressure, measurements may be

conducted under conditions of constant density in order to provide more

definitive tests of dielectric theory. Measurements on a series of alkyl

halides are planned to examine the correlation between dielectric relaxation

and the liquid free volume.

48
Dielectric measurements on materials under high pressures provide a means for

testing dielectric theory. (See p. 48.)

Precision Measurement of the Dielectric Constant of Solid Bodies.

A new three-terminal dielectric cell was completed and used to make precise

dielectric constant measurements by the two-fluid method, which does not

require electrodes on the specimen. A special specimen of fused silica was

prepared to check the method. The excellent results obtained showed that

the dielectric constant of a well-made disk specimen can be obtained to within

better than 200 ppm between 100 c/s and 50 kc/s.

In connection with this program, the guard gap correction was examined

theoretically. This correction allows the effective area of a three-terminal

electrode to be calculated with high precision.

The techniques of preparing dielectric specimens of polymeric materials were improved to the extent that disk specimens 8 cm in diameter can be

prepared with a variation in thickness of only about 5 p,. This improvement

is mainly the result of better control in use of the well-known Schieffer abrasion

machine. Such accurate control of thickness is important in the precision

of dielectric measurements.

Humidity-Time Studies of Dielectric Constant and Loss Index.

In this continuing program, the dielectric constant and the loss index of a material were measured as functions of time after an initial abrupt change

from less than 1.5 percent humidity to 52 percent humidity, or the reverse. Because of advanced developments allowing precision dielectric measure- ments without specimen electrodes, specimens without metal electrodes were measured and preliminary results obtained. Measurements are in progress on polystyrene, polyethylene, polycarbonate, polytetrafluoroethylene and its copolymers, and poly (1,4 cyclohexylenedimethylene terephthalate)

49
Theoretical Studies on Dielectrics. Theoretical work was completed

on the relaxation spectrum of an Ising lattice with dipole-dipole interaction.

In the simplest approximation with no interaction, such a lattice gives a

single dielectric relaxation time. The present calculations show that dipoledipole interaction leads not only to the anticipated principal relaxation time,

hut also to a set of shorter relaxaton times of lower intensity.

Chain-Folding in Polymer Crystals. Linear highly crystal! izable

polymers tend to crystallize in thin crystals (lamellae) having upper and

lower surfaces that consist of chain folds. The polymer chain axes are perpendicular to the large flat surfaces. Such crystals are of great importance

to understanding the mechanical and dielectric properties of semicrystalline

polymers.

A detailed theoretical analysis of chain-folding in polymer crystals was made from the viewpoint of nucleation and growth theory. Fluctuations

of fold length that occur during the growth of a layer were taken into account.

The results cast some doubt on the existence of a "transition" in the growth

rate near the melting point as predicted elsewhere. In certain limiting

cases, the theory gives the same results as a simplified theory published

earlier. In particular, the critical nucleus length fairly near the melting

point is given by l'a = 2<je / &f-\-kT/b0 cr. Because A/ varies as A7\ the

degree of supercooling, V0 tends to increase with rising growth temperature.

(fcT/boo- is small' compared to 2trc /A/.) A transition does actually take place

in the growth rate at low temperatures (high supercooling), but this is not

expected to be observable in most polymers.

The surface free energies, o>, of the chain-folded surfaces of polyethylene

and polychlorotrifluoroethylene were estimated by both thermodynamic and

kinetic methods. For polyethylene, ue is about 60 erg/cm2

; and for polychlorotrifluoroethylene, 35 erg/cm2

. Lateral surface free energies, o-, have

also been estimated.

An experimental investigation of the change of thickness of chain-folded

lamellae on storage at constant temperature was recently completed. The

lamellae were found to thicken slowly on storage according to (t) = l' + B

log[(« — to) /to], where (t~ t0 ) is the age of a lamellar crystal and t0 , a time that is generally much smaller than (f — 10 ) . In polyethylene, B ranges

from about 45 to 65 A per decade of time, depending on the temperature.

A theory that explains most of this isothermal thickening effect was devised,

giving B values in the range studied experimentally.

Dielectric Properties of Polymers. As part of the continuing program on the electrical properties of polymers, the dielectric properties .of the

new and interesting polycarbonate polymers are being measured over wide

ranges of frequency and temperature. In general, the pattern set by the

earlier complete study on polychlorotrifluoroethylene is being emphasized.

Dielectric Properties of Dipolar Chain Compounds. The dipolar

derivatives of the n-alkanes (e.g., /i-bromides, n-alcohols, and esters) behave

as simple single-axis rotators in a crystalline field. In many cases, a state of hindered rotation appears abruptly at a sharp transition temperature in

50
the crystal (rotational phase transition) . Dielectric studies on these materials

provide a check on theories of dielectric constant and loss, and also give in- teresting information on the rotational phase transition. The rate of rotation

is often very rapid, corresponding to dielectric relaxation times of 10" 7 to 10"10

seconds. Work proceeded on instrumentation aimed at making accurate

dielectric measurements in the 10 to 1000 Mc/s region on esters, bromides,

and similar materials.

Molecules with spherical or near-spherical symmetry, such as CH3—C—Cl3 (methyl chloroform) , also exhibit molecular rotation in the solid state. Dielectric studies on this class of materials are in progress.

Microwave Absorption in Compressed Gases. A systematic study

of the nonresonant (relaxation) spectra of a number of gases consisting of

symmetric top molecules (e.g., CH3 C1 and CH3 CN) in a variety of nonpolar

foreign gas mixtures was completed. Well over 100 systems have been

examined during the past year. Since the relaxation times are governed

simply by bimolecular collisions at the densities in question, these data

yield effective collision cross sections for molecular reorientation. With

development of the theoretical interpretation of these cross sections now in

progress, this work should provide a new and versatile method of studying

intermolecular forces, especially the anisotropic contribution.

These 200-cm spheres were used to study

sparkover voltages.

Results were in substantial agreement with international

sphere-gap tables. The range of 30- to 75-cm spacings between the spheres represented a voltage

range of 750 to 1550

kv. (See p. 52.)

51
High Voltage. A study has been completed of the negative impulse

-|>mku\<T voltage- foi 20()-cm spheres at spacings from 30 to 75 cm OVel

the voltage range from 750 to 1550 kilovolts (kv). The results obtained were in substantial agreement with currently accepted international sphere

gap tables- Other activities of a consolidating or preparatory nature included work

on the 350-kv instrument transformer, the "Mighty Pike," for the Ontario

Hydro Electric Power Commission. Work on the design of a compressed

gas capacitor to replace the "Mighty Pike" represented further consolidation

of this program for using capacitance dividers in voltage transformer calibrations. A second high-voltage d-c resistor was constructed to extend the

range of our direct-voltage measurement capabilities.

Most effort in the program to develop improved techniques for the cali- bration of inductive voltage dividers, as well as in the joint effort within

the Bureau in developing impulse voltage and current measuring techniques

of importance in the study of exploding wire phenomena, has been directed

toward the design, construction, and evaluation of equipment.

2.1.4. RADIO STANDARDS

The Radio Standards Laboratory is responsible for providing the central

basis for electromagnetic measurements above 30 kc/s in the United States

and for assuring international coordination of such measurements. The

laboratory conducts basic research on physical principles and fundamental

engineering techniques which have applications in the field of radio science.

This research leads to the establishment, maintenance, continued improvement, and international coordination of a comprehensive set of national

standards and precision measurement techniques for fundamental electromagnetic quantities. Extensive contact is maintained with other government agencies and with industry to keep pace with scientific trends which

will establish future measurement requirements and to disseminate information concerning precision electromagnetic measurements.

In addition to the national standards, this laboratory provides new theories

which radio scientists can exploit, new measuring devices which the instrument industry can produce, accurate design data for radio materials, cali- bration and broadcast services which furnish standards of radio measure- ment to hundreds of industrial and Government laboratories over the country,

and consultation and instruction to assist other laboratories in the solution

of problems in this field. To better pinpoint the connection between measurement accuracies and the

performance of major radio-electronic systems, the laboratory has begun a

series of seminars in which speakers from industry are invited for one- or two-day meetings with laboratory personnel. Three seminars have been held

so far and the results have proved very helpful in clarifying needs and

priorities.

52
Because of the continued and increasing demands for electromagnetic

measurement services, considerable work was done during the year in defining

long-range plans for the Radio Standards Laboratory. Most of this information was presented in extensive series of tables and charts which outline the

measurement and calibration capabilities now available and those which

might be furnished within five years. Also, with the aid of a special appropriation, design work began on a new multi-million dollar building for the

Radio Standards Laboratory.

Theoretical Physics. The far field of an antenna radiating into a

half space may, in principle, be obtained from the two-dimensional Fourier

transform of near-field values. However, the measurement of the near field may be affected in a complicated way by the characteristics of the measuring

antenna. The theory was developed of a measuring antenna of arbitrary but

known characteristics, under the assumption that multiple reflections between the measured and the measuring antenna are negligible. This work

was motivated by a need for precise, inside-the-laboratory measurements on

an electrically large aperture antenna in a microwave Michelson interferometer, but the results may be of wider interest.

In connection with the plasma physics program, correction terms to the

equation-of-state of an ionized gas were obtained via new methods of quantum

statistical mechanics. These results have led to a better understanding of

the role of the basic particle interactions in a plasma.

RADIO STANDARDS PHYSICS

The Bureau's program in radio standards physics furthers the precise and

fundamental study of physical constants and matter relating to radio science.

It also establishes uniform, accurate standards of measurement in areas of

frequency, time, and material properties, and disseminates these standards

to the general public. The work is, for the most part, dictated by the re- quirements of the rapidly expanding electronic and space industries and

makes possible a greater accuracy of performance by both private and

Government agencies. The staff provides a readily available consulting

service to industry, Government agencies, and individuals.

Fort Collins Standard Radio Transmitting Site. Construction is

practically completed on the new facility at Fort Collins, Colo., which provides

a transmission of standard low frequency (LF) and very low frequency

(VLF) carrier signals with high phase stability. On July 5, 1963,

the low-frequency station WWVB (60 kc/s) began transmitting from the

new site near Fort Collins, Colo., with a radiated power of several kilowatts

and with the carrier phase locked to the U.S. Working Frequency Standard.

Time signals will be added and the carrier power will be increased within

the next few months. Measurements near Los Angeles, Calif., and Chattanooga, Tenn., gave values of received field strength of about 150 and 100

microvolts per meter, respectively. Station WWVL (20 kc/s) began operating at the new site during the late summer. This station provides standard

frequency signals and will serve as an experimental facility to develop tech53
View from halfway up one of the 400-foot towers supporting antennas for the new LF and VLF standard frequency transmitting stations at Fort Collins, Colo.

The "helix house" (center foreground) contains the helical tuning device for

the antenna. Furrows show the grid pattern of the ground wires. (Seep. 53.

)

niques using narrow-band signals to provide means for clock synchronization

from a single station over wide areas of the world. The facility will also

enable the Bureau to accelerate additional research, development, and services

related to LF and VLF frequency and time broadcasts. Because of the high

phase stability of LF and VLF signals, these broadcasts provide wide dis- semination of frequency and time standards with a high degree of received

accuracy. A large part of the cost of the 20-kc/s station was provided by

the National Aeronautics and Space Administration.

WWVB and WWVL will not replace the shortwave transmissions of WWV

and WWVH. The high-frequency signals require only simple receivers and

their accuracy is sufficient to meet the needs of television and radio stations,

electric power companies, amateurs, many businesses, and the general public.

Atomic Frequency Standard Research. A new cesium beam fre- quency standard, NBS (III), has been completed. The spectral line width

attained with this instrument is less than one-half (and the precision should

therefore be about twice) that of NBS II. The NBS I cesium beam was converted to a thallium beam for the purpose of evaluating a thallium transition

as the standard of frequency. Approximately the same precision is being

attained with thallium as with cesium and it appears that an improvement of one order of magnitude in accuracy over that of cesium can be expected. A

hydrogen maser, which is under construction, will also be evaluated as a primary frequency standard.

An NBS atomic time scale was established which uses the United States

Frequency Standard as a basis. NBS atomic time was related to time pulses

of WWV, to the atomic time kept by the Naval Observatory (A 1 Time) , and

to the time pulses of the Loran-C master station at Cape Fear, N.C. This

54
relation was determined to 5 microseconds by carrying a high-precision,

quartz-oscillator clock from Boulder to these three stations. This comparison

technique also gives the propagation delays between these three stations so

that absolute time comparisons may be made continuously by means of

propagated signals.

Theoretical work has been completed on the effects of high-intensity electromagnetic fields on atomic systems and the related effects of multiple quantum

jumps, the Bloch-Siegert frequency shift, and frequency shifts due to the

presence of a third state. Frequency shifts caused by the presence of additional signals in the excitation radiation have also been calculated theoretically.

Quantum Electronics. Research in progress in this area includes the

measurement of the velocity of gamma-rays by means of the Mossbauer effect,

the measurement of the fine structure constant by determining the fine struc- ture separation in singly ionized helium, and a study of the various mechanisms of inducing blue fluorescence in anthracene with the red light of a

"giant pulsed" ruby laser. Calculations have been completed on the intermediate field Stark effect in symmetric top molecules.

This new cesium beam frequency standard (which can also be used with thal- lium) is now being evaluated. Its length of 18 feet is about 8 feet longer than

earlier models. This added length should significantly increase the precision.

(See p. 54.)

55

714-691 0—64 5
Radio and Microwave Materials. Materials research is designed to acquire an understanding of the magnetic (primarily ferrimagnetic) , dielectric, and conductive behavior of materials at radio and microwave fre- quencies in terms of the atomic constitution and structure of matter, and to improve and develop standards and measuring techniques for determining

material properties.

Magnetics. The change of elastic modulus with magnetization was investigated in a number of ferrites. The elastic modules first decreases and

then increases with increasing external field for all of the ferrites investigated.

This is a new result and is similar to behavior observed in nickel when

measured by static methods but not when dynamic methods are used. The

decrease in the static modules is attributed to domain wall stiffness and a theory relating the two was developed. Fair quantitative agreement was found

between the experimental observations and the predictions of the theory.

Time-dependent demagnetization effects were also investigated for a number

of ferrites. A rather low temperature coefficient of permeability as well as an anomalous disaccommodation effect were observed in a cobalt substituted

specimen. The ferrite specimens of controlled composition which were used

in these investigations were prepared by the NBS materials synthesis group.

Further improvements in initial permeability-measuring technology made

it possible to cover the magnetic spectrum at radiofrequencies using only the

permeameter and a versatile variable-length cavity. Studies of the determination of gyromagnetic ratio and line width of polycrystalline ferrites

showed that disk-shaped samples in rectangular TE102 cavities at L-band

frequencies can be used in the same way as spherical samples are used at higher frequencies. It appears that the disk technique is the best method to determine the gyromagnetic ratio and line width at these frequencies. However, it is necessary to utilize demagnetization corrections even for very thin

disks, as was determined from an extensive study of ferrimagnetic resonance

properties as a function of aspect ratio. This indicates that numerous previ- ous disk measurements may be in considerable error. The study of the disk

technique was supported in part by the Navy.

A study of the mathematical representation of the complex tensor permeability was begun and quickly led to a basic investigation of ferrimagnetic resonance (FMR), especially of losses which may be related to spin waves,

because FMR losses determine the line shape of the resonance and these

losses in turn are often determined by spin wave effects. Two new and important methods have been evolved for studying the FMR loss versus coupling

to the spin wave spectrum. In one, resonant ellipsoids of various ellipticities

and orientations are used. The other requires intrinsic magnetic measure- ments at resonance and away from resonance on only one specimen shape

(rod or sphere). Computer programs were prepared for correlating ellipsoidal data with intrinsic data. A roundrobin among various government

and industrial laboratories was conducted on FMR and permittivity of 10

ferrite compositions.

56
Magnetic resonance techniques are used to determine the magnetic energy

levels, relaxation times, and transition probabilities of paramagnetic and

anti-paramagnetic crystals. Thorough studies were made of the electron

paramagnetic resonance (EPR) spectrum of a natural amethyst single crystal.

The spectrum is extremely complicated and resists analysis by the usual

crystal field methods; however, some information on the field splitting and

the species of the ions was obtained. An important observation is that

bleaching out of the purple color of the amethyst left the EPR spectrum es- sentially unchanged. The EPR spectrum of iron-doped synthetic quartz is also being investigated. A new method of comparing Z-band and .K-band

cylindrical cavities for EPR work was developed.

Dielectrics. National and international roundrobin dielectric measure- ments were undertaken to help establish the present limits of accuracy for

such measurements. High-temperature dielectric measurements received

further attention, and the importance of this was emphasized by the meeting

of an ad hoc committee representing 10 interested laboratories. Standard

reference samples were further studied, resulting in selection of two glass

compositions as standard materials for microwave frequencies. An available

second-order perturbation theory for computing the permittivity of various

samples in a resonator was investigated and gave rather accurate results. Preliminary results were obtained on the measurement of the dielectric constant of small spheres. Complex arguments become necessary for very lossy

materials when expressing the complex dielectric properties of a material

using complex propagation factors. A computer program was prepared for

cavity techniques to be used in investigating lossy materials.

Mathematical investigations were undertaken of the feasibility of calculating permittivity and permeability of crystals based on their structure. Preliminary results are promising.

Conductivity. Whiskers of pure nickel of considerable length were prepared for the first time. Copper whiskers have also been prepared. Since

whiskers are close to being "one-dimensional" single crystals, they are especially valuable for studying the effects of the surface on their electrical and

magnetic behavior. Nickel-halide platelets have also been grown.

Materials Synthesis. Ilmenite-hematite solid solutions were studied by

characterizing the dielectric and magnetic properties of the solid solution

series Ni^rMn/TiCvFeaOa. The electromagnetic properties of this system

resemble those of the ferrites.

Plasma. A quantitative understanding of the basic physics of atoms

and molecules in a high planetary atmosphere (essentially a plasma) is nec- essary for progress in physical interpretation of experiments and observations

performed in these atmospheres. Such understanding is vital to the solution

of basic problems of astrophysics and to the design, for example, of adequate

systems of radio communications between earth and experimental vehicles.

During the past year observations of the magnetoresistance of plasmas were made, utilizing both plane-parallel and cylindrical electrode structures. The

data agree in part with the theory, but the theory is suspect in the pressure

57
range in which magnetoresistance was observed. This work was supported

in part by the Advanced Research Projects Agency of the Department of

Defense.

Microwave Interactions With Plasma. Fast, accurate, and convenient diagnostic techniques are necessary to the understanding of processes

of formation and loss of plasmas. A knowledge of such processes in turn

permits the utilization of the plasmas as tools of the microwave and propagation engineer.

The surface wave diagnostic technique is being used to investigate nonlinear diffusion processes in a plasma in which the principal loss mechanism

is wall recombination. The basic technique is being extended to a timeresolved measurement in order to look into the thermalized afterglow of a

discharge. A Laplace transform technique has been developed to facilitate

the spatial resolution of electron density in the surface wave determination.

Speed of Light (Diffraction Correction). During the year the effort applied to this problem was largely devoted to analysis and computation

relating to the diffraction correction for the determination of the speed of

light with a microwave Michelson interferometer. It was shown that (1)

evanescent waves, (2) accidental mirror tilt, (3) variation of reflection

coefficient of the mirror with angle of incidence, and (4) the component of

the transverse electric aperture field perpendicular to the nominal direction

of the field have no significant effect upon the diffraction correction.

Some speed of light measurements have been made with encouraging

results. The standard deviation of a single measurement is of the order of

0.2 to 0.3 km/sec. It is expected that this deviation can be improved significantly for the final measurements.

Final tests are being conducted on this Michelson interferometer prior to measuring the speed of light at millimeter wavelengths. ( See p. 58.

)

58
Stark Voltmeter. The splitting of spectral lines due to the application of an electric field, which is called the Stark effect, offers an attractive

possibility for measuring high voltages with high precision. During the year an apparatus employing this principle has been undergoing preliminary tests

at voltages up to 5000 volts. This apparatus employs a Fabry-Perot resonator

as an absorption cell for the observation of a rotational transition of methyl

cyanide at 37 Gc/s. Short-time precisions of 1 or 2 parts, in 10,000 have

been obtained. In the next year the present, relatively crude, electronic

circuitry will be replaced and other improvements will be made with the

expectation that the precision will be improved by one or two orders of

magnitude, as allowed by the theoretical limitations of the method.

RADIO STANDARDS ENGINEERING

The Bureau's program in radio standards engineering includes basic re- search on physical principles and fundamental engineering techniques having

applications in the field of precision electromagnetic measurements. This

research leads to the establishment, maintenance, continued improvement,

and international coordination of a comprehensive set of national standards

and precision measurement techniques for fundamental electromagnetic

quantities in radio circuits. Dissemination of measurement accuracy is accomplished in large part through calibration services, and information on

precision electromagnetic measurements is disseminated widely through

publication, consultation, conference papers, invited talks, committee work

with technical societies, individual visits to other laboratories, and the NBSAir Force Working Group visits to Air Force contractors. Low-Frequency Calibration. New instrumentation for the rapid cali- bration of volt boxes has been virtually completed. In the calibration of a number of units, this new console has reduced uncertainties resulting from

random errors. All critical indications in the console are either digital or

null-indicating, and all preliminary computations are performed automatically

by a computer in the console. The operator needs only to add the data which

are entered directly on a calculator.

The high-voltage facility now offers steady-state calibrations up to 50

kilovolts (kv) with an uncertainty less than ±0.01 percent using direct current. Alternating-current calibrations up to 13.2 kv, with an uncertainty

less than ±0.2 percent at 60 or 400 c/s, can also be performed. The recent

completion of a grounded safety enclosure and control console adds to the

convenience of measurement and the safety of personnel.

The internal loading errors in inductive voltage dividers of a specific design were analyzed to provide a basis for the construction of 10- and 20-section

dividers having known relative errors. A method of complementary measure- ments has been developed for the absolute measurement of certain nonzero

errors in these dividers. The goal of this work, which is still in the experimental state, is a simple method for the accurate absolute establishment of

alternating-voltage ratio over a wide frequency range.

59
Portions of the Wenner precision bridge have been insulated with Teflon

and satisfactory measurements at 25 °C can now be made on 1-megohm

standard resistors.

A new standard cell calibration console incorporates facilities for standard

cell comparison and temperature determination of the regulated oil baths.

By using both a microvolt potentiometer and a specially modified sensitive

standard cell comparator, two operators at the console can measure independently and simultaneously the electromotive forces of standard cells. High-Frequency Standards and Calibration. A method has been

developed for calibrating high-frequency incremental air capacitors to an

accuracy within 0.1 percent (limited mainly by their low-frequency calibration accuracy). In conjunction with this technique a dual twin-T highfrequency bridge is being constructed, and mathematical study indicates

that the circuit constants may be adequately evaluated by using only cali- brated capacitors. The basic accuracy of this bridge will then be limited

by the accuracy of the incremental capacitors used in its calibration.

The assembly of an ultra-high-frequency coaxial reflectometer has been

brought nearly to completion by the design and construction of a symmetrical

four-port directional coupler and a coaxial tuner of incremental capacitance

and constant inductance. An interesting sidelight, also in the coaxial field,

is that according to measurements made by the laboratory the open-circuit

fringing capacitance for a precision % X l/2 inch air line, measured by a

three-terminal method, is over 10 percent less than the computed value found

in the literature.

Given conductors of any complicated shape, with uniform current density

(direct current), their self-inductances and mutual inductance can now be

calculated exactly from equations developed by the laboratory. This work

has been extended to the high radiofrequencies with an approximating technique for evaluating the resistance and inductance of conductors with less complicated shapes. Using a high-speed computer, this method yields high

accuracies.

By modifying the design of radiofrequency (rf) -voltage bolometer bridge

mounts the accuracy of 300 to 1000 Mc/s sinusoidal unbalanced voltage

measurements were improved from within ±5 percent to within ±1 percent

based upon comparison with power measurements. Promising results were

also obtained in extending the frequency upward, with accuracies of about

10 percent at 2000 Mc/s. Extension of calibration services is subject to development of stable interlaboratory standards and further verification.

Development of a balanced continuous wave (cw) rf voltage, and an rf current standard and associated measurement techniques, was nearly completed for frequencies to 1000 Mc/s. These are to be incorporated in NBS

field-strength standards which are expected to be completed for these fre- quencies during 1964.

A noise power comparator system, designed to measure noise power from

10_1S to 10~21 watts with a precision of at least 0.02 percent, has been as- sembled and is undergoing preliminary tests. This improvement in sensitivity

60
and precision is expected through the use of a two channel radiometer (instead of the usual single-channel device) which has been developed by the

staff. Several types of very-high-precision noise sources are being developed to cover the needs of (1) high-level sources (up to 30,000 °K equivalent noise

temperature), (2) moderate-level sources (equivalent noise temperatures

within a few hundred degrees of room temperature), (3) low-level sources

(equivalent noise temperature to 77 °K or lower), (4) variable impedance

sources, and (5) ultra-high-precision, constant power, invariant impedance

sources. Reference sources using emission-stabilized temperature-limited

diodes and temperature-stabilized impedance networks in oil baths and

furnaces have been constructed. Evaluation of these sources is in progress.

A mode filter was constructed for use in a 3.2-in.-diameter waveguidebelow-cutoff attenuator. The filter attenuates the undesired TM0i mode by

98 decibels (db) and attenuates the desired TEn mode by only 0.2 db.

Significant progress has been made in the development of temperaturestable thin-film resistive elements. The elements are made by the vacuum

evaporation of a combination of metallic alloys. By proper control of

fabrication parameters, the resistors are stable with full power dissipation

under ambient conditions of 200 °C. The temperature coefficient can be controlled to values less than 50 ppm/°C. Resistors have been fabricated with

values up to 350 ohms per square, and work is in progress to determine the

maximum value obtainable.

The accuracy of rf voltage calibrations up to 30 Mc/s was improved by

one order of magnitude, to within approximately 0.1 percent. This was

achieved through improvements in the national reference standard and the

installation of thermal voltage converters as working standards. Precision

of measurement in the microvolt region was improved by one order of

magnitude by installing new detecting devices in the microvolt calibrator.

New and extended high-frequency impedance calibration services include

three-terminal capacitance at 100 kc/s, 465 kc/s, and 1 Mc/s for values ranging from 0.01 to 100 picofarads (pf), and the extension of coaxial measure- ments to frequencies as high as 1 Gc/s. In the area of primary standards,

a computer program has been completed which yields the exact characteristic

impedance of a coaxial line as a function of frequency. The computer program provides rapid evaluation and incorporates the Bessel functions for the

corrections arising from the skin depth of current penetration.

In high-frequency attenuation, the upper frequency limit has been increased

from 5.6 to 10 Gc/s, and the accuracy from 0.3 to 4 Gc/s has been increased

from 0.1 db/10 to 0.05 db/10 over a 40-db measurement range. The calibration accuracies of loop antennas, in field-strength studies, have been improved

from 5 percent to approximately 1 or 2 percent at frequencies up to 30 Mc/s.

This is being accomplished by utilizing both "standard field" and "standard

antenna" techniques. The frequency range of dipole antenna calibrations

has been extended to 500 Mc/s.

61
Microwave Standards and Calibration. The international comparison of low-power microwave standards, begun in 1957, is being continued

and, during 1963, Japanese measurements on NBS mounts agreed with NBS

measurements to well within experimental error (0.5 percent). Improvements of the NBS facilities (current maximum error = 0.2 percent), through

reduction of noncomputable rf losses, were continued. Calibration service

is being extended to other frequency bands.

The design of a microwave high-power calorimeter is well advanced.

Testing and error analyses of the calorimeter and of an electron beam power

meter is being continued. A subtle but important error associated with the

use of the latter device has been discovered and analyzed. This error arises

through the effect of the thermal velocity distribution in the electron beam

on the magnitude of the reference current.

In recent years, the laboratory has offered reflection coefficient calibration

services in several rectangular waveguide sizes. During the past year emphasis has been placed on extending these services to coaxial components.

A thorough study of available coaxial connectors has identified two designs, one a commercial design and one the NBS-Woods design, either of which

when assembled according to specifications contributes a reflection coefficient

of less than 0.005 ( VSWR less than 1.01 )

Two reflectometer systems have been developed for measurements on

coaxial devices—one is a hybrid system comprised of a coaxial precision

line and associated elements appended to a rectangular waveguide reflec- tometer through a coax-to-waveguide adapter; the other is an all-coaxial

system. The hybrid system has been thoroughly tested and has an accuracy

equivalent to the existing waveguide systems. Components for the all-coaxial

system have been developed and carefully tested. Their performance indi- cates that an all-coaxial reflectometer with an accuracy equivalent to existing reflectometers is possible, but tests must still be made on the total sys- tem. At wavelengths exceeding about 10 cm, the all-coaxial system will

occupy less space than the hybrid system.

Development of a phase-shift-measuring system, utilizing a sliding short

circuit as a standard, and capable of measuring phase shift to an accuracy of

0.01 degree, has been completed. This system has been thoroughly tested

and is now ready for development as a national microwave phase-shift cali- bration serviceThe development of the modulated subcarrier technique of attenuation

measurement culminated during the year with the completion and submission

of papers describing detailed analyses of the components. A system was

constructed for study in the calibration center. Among the advantages

offered by the modulated subcarrier technique of attenuation measurement

are (1) only one oscillator is required, (2) relatively inexpensive but highly

accurate audio voltage transformers can be used as attenuation standards,

(3) phase information is readily obtainable with the same system, and (4)

deviation of the detector from linearity becomes significant at higher power

levels than in the case of the intermediate frequency (IF) system.

62
The development of millimeter-wave technology in recent years has extended

the spectrum of useful frequencies, and the present rapid development of

infrared and optical coherent sources presages a range of useful frequencies

which will exceed by many times the range available now. Increasing effort,

therefore, is being diverted to meet the demand for standards over this vast frequency range. A variety of components for use at approximately

40 and 70 Gc/s and part of a system for use at approximately 150 Gc/s

have been acquired. A conventional 69.810-Gc/s reflectometer has been

constructed and is undergoing tests. The sources have been phase-locked to the sixth harmonic of a phase-stabilized X-band generator, and an encouraging preliminary performance study of the millimeter wave reflectometer has

been made.

A heterodyne receiver employing a phase-stabilized local oscillator has

been provided for reflection coefficient and attenuation measurements at 69.810 Gc/s and a method is being developed for the measurement of milli- meter wave power at about the one-watt level. For microwave horn gain calibrations in the absence of "darkroom" facilities, a nanosecond (nsec) pulse technique has been developed. Tests using

available components have shown that the system in its present state of development, employing 40-nsec pulses in a clear volume 60 ftX60 ftX20 ft, would be capable of an accuracy within 1 percent providing corrections

could be made for any dispersion and bandwidth limitations of the horns

to be calibrated. Application of the technique to waveform analysis is being considered.

The development of a calibration system which uses a transfer method of

comparing bolometric power-measuring devices has led to a new calibration service for low-level cw power measurements in the frequency range

of 12.4 to 18.0 Gc/s (WR62 waveguide) . This system is the first in a series

of microwave power calibration systems which are under development to

utilize this method in the higher microwave region. During this developmental work, the implementation and procedure of this transfer method

have been considerably simplified; it is expected that further refinements

will be achieved as the work progresses.

The use of a new material for the hot-body source in the United States

National Standard of microwave noise has resulted in considerable improvement in the operation of this standard and reduced the time required to

stabilize the system to about one-fourth that which was previously necessary.

The material, silicon carbide imbeded in beryllium oxide, was selected after

study and experimentation with various possible materials.

Further work on the waveguide rotary-vane attenuator revealed an additional vane-displacement error caused by eccentricity and backlash of the

mechanical gear train. Analysis has led to a precise method of specifying

this systematic error. With this knowledge, the rotary-vane attenuator can now be used more accurately, and thus it might be that this attenuator

will be useful as an rf attenuation standard.

63
A new transfer instrument, designed and built by the Bureau, is used for the

intercomparison of microwave power meters. A bolometer unit is being cali- brated. The insulated chamber (which is normally closed) stabilizes the

temperature around the equipment. (See p. 64.)

A new approach to the fabrication of precision rectangular waveguide,

in connection with the development of reflection calibration systems in

several waveguide sizes, has resulted in improved accuracy of calibration

for small values of reflection coefficient. The method consists of a "gageblock type" construction which allows partial adjustment to an exact rec- tangular shape, and it has provided a precision waveguide section in WR.90

waveguide (8.2 to 12.4 Gc/s) with internal dimensions approaching a toler- ance of ±0.00005 in. and a precision waveguide section in WR62 waveguide

( 12.4 to 18.0 Gc/s) with a tolerance better than ± 0.00005 in. Fabry-Perot Interferometer Used as a Dilatometer. A dilatometer which measures linear displacements as small as 10~7 cm has been

developed. This instrument, based on the principle of the Fabry-Perot

interferometer, is being used in studies of the static strain resulting from the

magnetization of ferrites. It can also be used to determine the strains en- countered in thermal expansions, the piezoelectric effect, or other phenomena

in which the strains are similar in magnitude. Work on the dilatometer was

sponsored jointly by the Army and the Navy.

In the interferometer, the specimen whose dimensional change is being

determined is held firmly between an adjustable tailstock and a moveable

table on which is mounted one mirror of the interferometer. A telescope,

having a micrometer eyepiece for the determination of the change in diameter of the fringes, is used to form the interference pattern- When a strain

64
is induced in the specimen, the resultant movement of the mirror is detected

as a change in diameter of one of the rings in the fringe pattern.

Using a mercury 198 light source, a mirror separation of 2.5 mm, and a telescope with a focal length of 25 cm, the magnification of the instrument is of the order of 10,000. For example, if the mirror moves 10"7 cm, the ring

diameter changes by 10"3 cm, a change which can easily be measured.

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 such heat measurements as thermal diffusivity, heat capacity,

and heat of combustion. Internationally agreed upon temperature standards

are maintained to assure a common scale upon which all temperature meas- urements are based. A strong research program aims to keep these standards

adequate for the expanding scientific needs. In addition, supporting re- search on the physical properties of solids and gases at both low and high

temperatures includes studies in low-temperature physics, statistical thermodynamics, high-temperature processes, high-pressure thermodynamics, and in

various aspects of plasma physics.

An automatic thermocouple comparator has been put into operation, with

substantial resultant increases in efficiency and reliability of the calibration

procedure. Computer programs have been developed for analyzing lowtemperature heat-capacity data and for calculating the thermal functions.

The kinetics of a dissociation reaction have been established by combining

shock wave techniques with time-resolved absorption spectrophotometry. A

detailed calculation of the thermodynamic properties of ionized gases at high

temperatures has been completed.

Molecular Energy Levels Program. The major effort in this program, which is supported in part by the National Aeronautics and Space

Administration, is directed toward the accurate determination of the energy

levels of small molecules. Information of this kind is of fundamental importance to the interpretation and understanding of phenomena that occur

in environments at extreme temperatures or which are inaccessible, such as

electric discharges, flames, the upper atmosphere, comets, and stars. Recent work has emphasized the observation and measurement of the

spectra of diatomic molecules in the vacuum ultraviolet region, from 1100

to 2500 angstroms (A). The properties of the long-lived afterglows from

electric discharges through nitrogen have been investigated in the vacuum

ultraviolet. The spectra indicate that substantial numbers of very highly

energetic nitrogen molecules emerge from the discharge region and retain

their energy for long periods of time. The unusual conditions existing in

certain regions of the afterglow have permitted observations of many vibrational states of the nitrogen molecule not previously detected.

An apparatus has been constructed for observing the vacuum ultraviolet

absorption spectra of transient species produced by the flash photolysis of

65
gases. By using a flash lamp to produce a high-intensity, short-duration

continuum it is possible to record absorption spectra of transient species

from 1100 to 3500 A, with time resolution as short as 10 microseconds.

Plasma Transport Processes. An apparatus for operating a magnetically confined low-pressure arc has been completed with the installation

of a 125 kilowatt d-c generator to supply power to the magnet. The dis- charge column length is variable up to a maximum of 50 cm, and the maximum

magnetic field is 7000 gauss. Study of the transverse oscillations of the

plasma column, which are due to standing waves similar in character to Alfven

waves, leads to estimates of the density and electron temperature which agree

satisfactorily with information obtained from Langmuir probes and from

relative intensities of spectral lines. The plasma density is between 1013 and

1014 cm-3 and the electron temperature about 5 ev for an 8-A argon discharge in a 1300-gauss magnetic field. Under these conditions the ion temperature is roughly 1 ev. Delivery of a 1.5-meter grating spectrometer was made and the specified

performance obtained. The instrument was fitted with a punched tape recording system to facilitate use of the computer in obtaining radial intensity

distribution functions by the Abel transformation. Examination of the

departure from Saha equilibrium in the excited state populations of A n, and an estimate of electron density from Stark broadening of the Balmer

lines of added hydrogen, are under way. The first intensity measurements

show that excited state populations are above Saha (with respect to the elec- tron continuum) for levels below about 21 ev. Arrangements were concluded for Professor Susumu Takeda of the University of Nagoya, Japan, to spend a short period in residence to initiate

experiments leading to an estimate of plasma density from the phase shift

of a reflected microwave whose frequency is subcritical. The microwave

equipment has been assembled and tested and is ready for measurements

on the plasma.

Automatic Thermocouple Comparator. A thermocouple comparator has been developed which automatically records data during the comparison calibration of platinum versus platinum-rhodium thermocouples.

This device, which places the data on punched tape prior to reduction by a computer, makes the calibration procedure more rapid and convenient, and

eliminates the errors which may occur during hand recording and transfer

of the data.

Use of the comparator permits automatic recording of the total electromotive force developed by the standard thermocouple and the difference

between this emf and that of as many as 11 test thermocouples. The data can be recorded in several different sequences. One method is to set the

comparator so that a complete set of readings is taken for every 0.5-millivolt change in the emf of the standard. Alternatively, readings can be

initiated by clock control at preselected time intervals, or by manual control.

Both the emf of the standard and the difference emf's are converted from

analog to digital form by means of shaft position encoders attached to self66
Automatic thermocouple comparator records data during, comparison calibrations. The calibration information comes out on punched paper tape for computer input. Such automation enables the Bureau to provide more rapid cali- bration service, and permits scientists more time in which to perform the re- search necessary for more accurate measurements. (See p. 66.)

balancing potentiometer indicators. These digital data are transferred to a paper tape and, after processing on an automatic typewriter, put on punched

cards. The data are then reduced by a 7090 computer, which fits an equation

to the difference between the test and standard thermocouple emf's, combines

this equation with that used to compute temperatures from the standard's

emf's, and computes the emf developed by the test thermocouple at 1 -degree

(either Celsius or Fahrenheit) intervals.

Thermodynamic Properties of Light-Element Compounds. Under

the sponsorship of the Advanced Research Projects Agency of the Department

of Defense, the Bureau is continuing its comprehensive program of research on the thermodynamic properties of simple light-element substances which

are important in rocket propulsion. The substances being specially investigated are the two-element and three-element compounds formed by beryllium,

aluminum, and lithium with fluorine, chlorine, oxygen, nitrogen, carbon, and

hydrogen. These substances are important combustion products of rocket

combustion, and some of their properties are therefore being investigated over

a very wide temperature range (0 to 6000 °K) and up to pressures of 100

67
atmospheres (atm). Nine research groups are engaged in a critical correlation of the available published data and in a systematic experimental program

to measure new values.

An important part of the program is devoted to three types of thermal

measurements on solids—heats of formation, heat capacities at low temperatures, and enthalpies at moderately high temperatures. The combination of

these three properties makes it possible to calculate energies and thermodynamic stabilities of combustion products over wide temperature ranges.

It was found that the most important substances under consideration for which

these three properties had never been measured accurately are four twoelement compounds (BeF2 , BeO, Be.iNv, and A14C3 ) and three three-element

compounds (BeAl2 04 , Li2 BeF4 , and Li 3 AlF6 ), and a program of determining

these missing properties is continuing.

The high accuracy of these thermal measurements on three-element com- pounds has an additional, indirect advantage in practical applications. A

unique opportunity is afforded to test the assumption which is commonly

made that the properties of numerous such compounds of the same type,

which in many cases have never been measured, may be estimated simply as

the sum of those of the simpler compounds from which they were formed.

For example, the heat capacity of BeAl2 04 was found to be equal, within a few tenths of one percent, to the sum of those for BeO and A12 03 (measured

earlier at the Bureau) for every temperature so far investigated (0 to 900 °C)

Other groups of the overall program are investigating the vaporization and

gas properties of such substances as those above. One such group used a newly developed precise high-temperature "transpiration" apparatus to pass an inert gas over solid aluminum fluoride (A1F3 ) and measure its vapor

pressure. The heat of vaporization simultaneously found was combined

with the heat of formation of the solid, measured by fluorine calorimetry

earlier in the program, to give an accurate heat of formation of the gas. At

the same time, the results substantiated a recent report that small amounts of

the vapor are in associated form (A12 F6 ). The apparatus is being 'modified

to study the thermodynamic properties of the hitherto unknown gases A1F2 C1

and A1FC12 . The final stage of experimental research of the above types is the critical

correlation of its data with all other data and related properties, to yield an

interconsistent and definitive set of tables of heats of formation and thermodynamic functions. The program is assuming this responsibility for the

compounds of beryllium, aluminum, and lithium, and in so doing is participating in a permanent, fundamental activity of the Bureau.

Computer Analysis of Low-Temperature Heat-Capacity Data. In connection with a program to automate low-temperature heat-capacity measurements, computer programs have been developed to analyze the data and

to calculate the thermal functions from the analysis. New data on various

substances are being published at an increasing rate which are either more

accurate than the older data or are on entirely new substances. The heat

capacity is a complicated function of the temperature and no single form of

68
equation is known that can represent the heat capacity from 0 to 400 °K, the

range of low-temperature heat-capacity data, for all substances with the

accuracy attainable experimentally. A computer program has been developed

to analyze the data using several overlapping equations, the best values in

the region of overlap being selected "manually." To date, the literature data on over 80 substances have been analyzed and the thermal functions calculated

from the data have been reported. A computer program that requires no "manual" operation is now being developed.

Thermal Diffusivity Standards. At high temperatures there is an

urgent need for standards of thermal diffusivity and its closely related property, thermal conductivity, which is the product of thermal diffusivity and

heat capacity. For poor heat conductors, microcrystalline glasses look

promising in that they are opaque, are electrical insulators, and are available

commercially as reproducible materials. Thermal diffusivity measurements

were made to over 1000 °C on one microcrystalline glass. The measurements

indicated that this material should be adequate as a standard up to 1000 °C,

accurate to within several percent. For higher accuracies two precautions

should be taken: first, the material should be heat-treated near 1000 °C to become completely reproducible, and second, care should be taken in using

this material near 175 °C where there is a small transition in thermal diffusivity

and some other properties.

Microwave Spectroscopy. A continuing program in microwave spectroscopy at the Bureau, partially supported by the Office of Naval Research,

is concerned with measuring the radiofrequency and microwave spectra of

diatomic molecules, with particular emphasis on those molecules that are known to be present in the interstellar gas. Precise knowledge of their spectra

is necessary before these molecules can be searched for and studied by radioastronomical methods. Recently, laboratory measurements were made on

the low-frequency (approximately 100 Mc/s) line spectrum of the molecular

radical SH, generated by the chemical reaction of atomic hydrogen with

hydrogen sulfide gas. Similar chemical techniques are being investigated as means of producing and studying other radicals of astrophysical interest,

such as CH and SiH.

Nuclear Orientation. Studies made of the photoneutron cross section

in the region of the giant resonance, using an alined holmium target, directly

confirmed the theory that this cross section is associated with the two axes

of the deformed nucleus. This experiment, aside from the importance of

demonstrating this phenomenon, was the first successful experiment using an oriented nuclear target with an accelerating machine. The work was

performed at the NBS Betatron Laboratory in collaboration with the High

Energy Radiation Laboratory. The alined holmium target was obtained by

cooling a large single crystal of holmium ethyl sulfate to 0.29 °K with the

NBS portable He3 refrigerator.

Shock Wave Reaction Kinetics. Work has been completed on an

experimental investigation of the kinetics of the dissociation reaction N2 F4?±

NF2 . The experiment involved the combination of shock techniques with

69
time-resolved absorption spectrophotometry. The experimental data show

that the reaction proceeds by a unimolecular mechanism. The experimental

activation energy was 19 kcal/mole at a total concentration of 6 X 10~2 mole/

liter over the temperature range 343 to 410 °K. (The dissociation energyis 19.8 kcal/mole.) The Arrhenius frequency factor in the high -pressure

limit was estimated to be 2 X 1015 sec" 1

. This result indicated that free rotation about the N-N bond probably occurs in the energized activated complex.

An experimental determination of the absorption coefficient for the optical

transition that the difluoroamino radical (NF2 ) undergoes for light at a wavelength of 2602 A was determined at temperatures between 438 and

870 °K. The mean result was 535 liters/mole cm. Thermodynamic Properties of Gases at High Temperatures. A

reasonable approach has been sought for the calculation of thermodynamic

Apparatus used in the determination of the spectra of diatomic molecules

thought to be present in interstellar gas. Precise determination of the line

frequencies is necessary before such molecules can be searched for and studied

by radiotelescopes. (See p. 69.

)

70
properties of ionized gases at high temperatures, in a study sponsored by the

Air Force Special Weapons Center. This includes a treatment thought to be

satisfactory for atoms and atomic ions in circumstances of interest in magnetohydrodynamics as well as for more usual equilibrium conditions. In

the past, some approaches have encountered computation difficulties related

to the divergence of the partition function of an isolated atom. The present

practical solution of the problem uses the fact that under the frequently

plausible conditions of Debye screening, the number of states available for

occupancy can be estimated easily in a semiclassical approximation. For a

first approximate calculation scheme, the energies of hydrogenic levels have

been taken as modified by Debye screening according to first-order perturbation theory. The levels are broken off where their available number agrees

with the semiclassical estimate. As the behavior of the screening is different

at different concentrations of ions and, as it also depends on temperature,

there is a joint influence on the partition function and so on the thermodynamic properties. It is only by a careful accounting of the appropriate

derivative relations that the otherwise unknown thermodynamic effects of

these dependences can be taken into account. Programming is in progress

to perform the required operations in a systematic manner via electronic

computer.

A study of the partition function for diatomic molecules at high temperatures has similarly been in progress according to a second virial type

formulation. This has application also to intermolecular interaction effects.

2.1.6. ATOMIC PHYSICS

Atomic physics reserach has continued to be oriented primarily toward the

determination and evaluation of fundamental data relating to atomic properties and interactions and toward a more basic understanding of the

phenomena involved. The major portion of this work is of primary interest

to the fields of plasma and astrophysics, although the data derived have a wide area of application in physics, astronomy, chemistry, and engineering.

The Bureau, with partial sponsorship of the Advanced Research Projects

Agency (ARPA) and the National Aeronautics and Space Administration,

continues to be a major international center for research on atomic properties, and the accumulation and evaluation of the published literature in

its two data centers on atomic energy levels and atomic transition probabilities represent valuable contributions to the scientific community.

In the materials field, properties of semiconductors are under study in a continuing extensive research program partially sponsored by ARPA. This

research is now being augmented by a study sponsored by the Atomic Energy

Commission of the optical properties of thin films in the vacuum ultraviolet

region.

Continuum States in Rare Gases. New information on the atomic

structures of helium and some of the other rare gas atoms was obtained

in a series of independent experiments which utilized both electron and

714-691 O—64 6 71
Studies of electron interactions in the rare gases have yielded a new and fundamental insight into the character of energy states in these gases. The interactions occur in the large cylinder (center). See p. 71.)

photon interactions. These experiments yielded a self-consistent picture

of the higher energy levels in these rare gas atoms, and theoretical studies

gave a new and fundamental insight into the character of energy states in

atomic continua.

Photons produced in the vacuum ultraviolet spectral region by the accelerated electrons in the NBS 180-Mev synchrotron were utilized in studies

of the absorption properties of several of the rare gases. The ultraviolet

radiation obtained from the synchrotron is the only known pure continuum

available in this energy range, and it is well-suited to the study of the

detailed absorption processes in the far ultraviolet.

A series of absorption features were observed in helium gas, at energies

some 35 volts above the energy necessary to ionize the neutral helium atom.

At these energies, two competing processes can take place : the ultraviolet

photon can either remove one of the electrons completely from the atom,

or can leave the atom in a short-lived neutral state by elevating both its electrons to higher excited states. Since these two processes are strongly

mixed, the observed spectrum exhibits the anomalous features characteristic

of autoionized states. Theoretical studies of the absorption characteristics of helium showed

excellent agreement with the observations, and have led to a greatly improved understanding of atomic energy states that are mixtures of discrete

and continuum states. New calculations for a series of autoionizing levels in helium indicated that relatively crude calculations can be expected to

72
predict level widths within a factor of two or three of experimentally determined values.

These same atomic states in helium were also studied through observations on the energy losses suffered by nearly monoenergetic electrons

passing through helium gas. These measurements were performed with new

apparatus designed to measure electron-scattering cross sections in the

range from 500 to 5000 electron volts. This apparatus will be used to make further accurate and detailed studies of electron-scattering cross sections

for various atoms as functions of both angle and energy.

Characteristics of energy losses of electrons scattered by helium were

in complete agreement with results of the experiments performed with the

ultraviolet photons from the synchrotron.

A new and extremely monoenergetic electron gun and an analyzer were

constructed and utilized in studies of the absorption characteristics of rare

gases. Experiments performed with this apparatus in helium gave evidence

of an anomalous transparency to low energy electrons. The observed

"window" in the helium gas was extremely narrow, and lay well below the

energy of the first excited state. In addition to those of helium, the absorption characteristics of neon and argon were studied in both the photon and electron experiments. In each case, results qualitatively similar to those described for helium were

observed. Numerous autoionizing states were identified, and in neon

two resonances below the first excited state were observed. No such lowlying states were seen in argon, however.

These studies are expected to yield data on the generalized oscillator

strengths in the continuum and to lead to an understanding of these states. The results will be of fundamental interest to both astrophysicists and plasma

physicists, and are necessary to the interpretation of astrophysical and

thermonuclear phenomena.

UMIT= 189.6 & 206 &

Absorption spectrum of helium obtained using the NBS synchrotron as a source of light. The ultraviolet radiation from the synchrotron is the only known

pure continuum available in this energy range. (See p. 71.)

73
Plasma and Astrophysics. The Bureau continues to be the world center for the collection and determination of much of the atomic data needed

by atomic physicists and particularly by plasma and astrophysicists. Such

data are important to the proper diagnostics and understanding of processes

occurring in hot gases. Work in this field was supported by ARPA and the

Bureau.

In addition to the work mentioned in the previous section on continuum

oscillator strengths, work on the determination of the discrete oscillator

strengths (or transition probabilities) in atoms continued.

Research continued on use of the wall-stabilized arc for the measurement

of transition probabilities. The shifts and widths of several oxygen lines were measured, and the results are in good agreement with recent theories on line broadening in dense plasmas. This method represents a new and

simple way of analyzing dense plasmas of heavy elements, and should lead

to a better understanding of high-temperature plasma phenomena.

The cross section for elastic scattering of the slow, 1-ev electrons by

hydrogen atoms was measured by the electrical conductivity method. In

contrast with earlier experimental measurements by research groups else- where, the result agrees well with recent theoretical values and confirms

the general consistency of the spectroscopic analysis of the hydrogen plasma.

The relative transition probabilities for a number of lines of singly and

doubly ionized oxygen were determined utilizing a magnetically driven shocktube. The results agree very satisfactorily with the theoretically obtained

values. No attempt was made to present absolute values, as attainment

of complete local thermodynamic equilibrium was somewhat uncertain.

Modified Hartree-Fock calculations of transition probabilities were completed for the major transitions in two- and three-electron atoms and ions.

Relative transition probabilities were calculated with the Racah methods

for the spectrum of doubly ionized vanadium.

Atomic Energy Levels. Emphasis continued to be centered on the

observation and analysis of the rare-earth spectra. Extensive laboratory observations, including the strong absorption lines and Zeeman patterns, were

carefully scrutinized to determine the ground state and over 100 "even"

levels for Ce I. The spectrum of Ce m was observed with a sliding spark, and

measured from 700 to 1100 angstroms (A). Some 2000 lines are known,

of which 75 percent are now classified. The strongest line of Ce in, A3055.589

A, may possibly be present in the solar spectrum, where an otherwise unidentified faint line has been observed at A3055.594 A. If this identification is correct, it provides the only evidence of a third spectrum among the solar

lines A > 3000 A.

Measurements and calculations of the Zeeman patterns of 1307 lines in

the first three spectra of ytterbium were compiled preparatory to a new description of these spectra comprising more than 6500 lines. Measurements

of approximately 10,000 lines of Tm I, Tm n, and Tm in were made, covering

the interval 2300 to 11000 A.

A new edition of the extensive solar spectrum table is near completion.

74
Highly accurate measurements were made of lines in the spectra of Krypton 86

and Mercury 198 for use as secondary wavelength standards. The orange-red

line in the spectrum of Krso has been the International Standard of length for more thah three years. (See p. 75.)

A theoretical study on the nonlinear effects in the spectra of elements in the

iron group contributed significantly to the understanding of the electronic

configurations in these atoms.

Wavelength Standards. The program on mercury atomic beams and

Zeeman filters, undertaken in connection with the redefinition of the meter,

concluded with experiments comparing the wavelength of the 2537 A line as obtained from these two sources. Highly accurate wavelength measurements

of additional mercury and krypton lines suitable for standards were also

completed.

Infrared Spectroscopy of Gases. The infrared absorption of a band

of carbon suboxide (C302 ) was measured under high resolution. Analysis

of the spectrum provided the first unambiguous evidence that this molecule

is linear and must have an unexpectedly low bending frequency. A parallel

band of ethane-l-C13 was also analyzed. The results are in agreement with

C—C bond length measurements obtained for propane.

A forbidden vibronic band of NO that was predicted to have a transition

probability produced by the interaction of the two electronic states was observed. Both frequency and intensity measurements were made. Within

experimental error, the intensity of the band was found to be the same as that

predicted theoretically.

75
Measurements and a partial analysis of 15 absorption bands of CH..D

were completed as part of an AEC-sponsored program of measurements of

deuterated compounds. Under the same sponsorship, measurements and

analysis of a number of bands of DCN were completed. This work complements a recently finished analysis of the spectrum of HCN. In addition

to furnishing values of potential constants and rotational constants for two

isotopic species, the work on HCN and DCN emphasized the importance

of including certain higher-order constants in the analysis so as to achieve

satisfactory agreement between the observed and calculated spectra. Such

higher-order terms were previously unnecessary, but the advent of higher

resolution and more accurate measurements has necessitated use of more

exact expressions for the energy levels. Shapes of Rotational Lines as Influenced by Pressure. Measurements were made on the pressure broadening of infrared absorption lines

for the gases HC1, DC1, CO, and HCN. In addition to some self-broadening

measurements, broadening by various types of foreign gases was investigated.

The broadening has been demonstrated to be nearly independent of the

vibrational level involved, although it does depend on the rotational level. The most significant work involves the measurement of the broadening of

HCN lines due to the pressure of HC1. These two molecules have a large

dipole moment and thus strongly interact when they approach each other.

This work was supported by the Cambridge Air Force Research Center and

the AEC in addition to the Bureau.

Absorption Spectra of Solids. The infrared spectra of several very

interesting solids were completed or are now under study. Infrared studies

of the compound 4CsCl • 3HC1 • 3H2 0 and its deuterated counterpart were used

to show that, contrary to previous expectations, they do not contain the

HC12 " ion but only the ions Cs+

, CI", and H3 0

+

. Work is in progress to determine if the elusive HC12~ ion is present in certain pyridine salts. Spectra of polyhalide compounds were also analyzed. These compounds

are similar to the recently discovered rare gas compounds (i.e., XeF2 ) and

are of great interest. The Bureau is uniquely suited for studies of polyhalide

compounds because of the availability of spectrometers which can be used

in the far infrared region where these spectra are found.

Solid State Physics. The research program in solid state physics,

which is partly supported by the AEC and the ARPA, concentrates on four

major interdependent areas: electronic transport, optical characteristics,

magnetic resonance, and dielectric properties. This experimental program

is supported by theoretical studies and by crystal growth and structure investigations. The main emphasis is on a group of semi-insulators and semiconductors (namely, the Ti-0 compounds: Ti-oxides and titanates) which

have important uses in many different fields (such as dielectrics, masers,

phototropic materials, etc.) . Other substances under investigation are spinel,

CdTe, PbF2 , and several azides.

A study was made of the electron spin resonance spectrum of molybdenum

in rutile. Fine structure, hyperfine structure, and superhyperfine structure

76
were observed and interpreted. Use of circularly polarized microwave

radiation enabled the unambiguous determination of the sign of the g-factor.

Measurements of the Seebeck coefficients of TiOo and SrTi03 down to 15 °K

have shown that the phonon-drag effect contributes most to the value of the

coefficient of rutile at low temperatures, while it seems to be absent in SrTi03 . Electronic energy band calculations for Ti02 indicated that the conduction

and valence band of this material are mixtures of Ti-3e? and 0-2p orbitals.

The binding is not completely heteropolar in nature. Qualitative agreement

with many characteristics of the substance can be obtained (energy band gap,

width of valence band, higher conduction bands, etc.) . A similar calculation

for cubic titanates (perovskites) is in progress.

The optical spectrum of Co in a Mg-Al-spinel crystal can be interpreted in

terms of calculated level schemes ( crystal field theory ) . The measurements

confirm that Co prefers the tetrahedral site rather than the octahedral one. The nitrogen nucleus in azides (NaN3 , KN3 , HN3 ) is being investigated by

means of nuclear magnetic resonance and quadrupole resonance techniques.

The quadrupole coupling constants of each of the three N nuclei in HN3 were

determined from the microwave spectrum.

Good crystals of CdTe were produced using the Bridgman method; the

photoelectric properties of this substance are being explored.

Electron Optics. A problem which has plagued electron physicists for

years is the production of well-collimated electron beams of low energy.

Such a beam is a basic requirement in almost every experiment in electron

physics and in many in atomic physics. A new and somewhat novel analysis

of the physics involved in the production of such beams has given rise to the

development of a series of electron guns of precise design. These guns, which

perform much better than previous designs, were utilized in the previously

described study of energy losses in rare gases.

Measuring Velocity of Light. A multifaceted program was instigated

to remeasure the velocity of light to at least one more significant figure. The

method involves the measurement of beat frequencies between two optical

lines emitted from a helium-neon laser. A comprehensive study to determine

the feasibility of detecting and measuring beat frequencies of the order of

1012 cycles per second between two optical lines in the helium-neon laser was

successfully completed. An experimental investigation was initiated by

Egerton, Germeshausen & Grier, Inc., under contract to the Bureau to determine the necessary design considerations involved in the construction of a modified cathode-ray tube for the beat frequency measurement.

Two helium-neon lasers have been constructed to investigate the various

methods of stabilization of the laser lines. These lasers are also being used

to investigate the various lines available for and most suitable for the beat

frequency detection.

Optical Pumping. For the past year, work progressed on an experiment to pump xenon 129 optically at 1469 A. A strong resonance lamp was

designed and constructed to give a radiation flux of approximately 1015

photons/sec per steradian at 1469 A with no appreciative self-absorption.

77
The radiation is emitted through a sapphire window fused to the lamp.

Experiments are now in progress to detect the optically pumped signal in xenon 129.

Magnetic Moment of the Proton. An experiment was undertaken to determine the magnetic moment of the proton in units of the nuclear magneton. It is hoped that this determination will lead to the resolution of a 50 ppm discrepancy in this constant reported by various investigators.

Experimental Atomic Collisions. A new instrument for the study

of photodetachment of negative ions is being completed. This instrument

will provide significantly greater resolution of both the ion beam and the

photon beam. Studies of the behavior of the cross sections near threshold

-for photodetachment of atomic ions will be undertaken without the assistance

of prior theoretical assumptions.

2.1.7. RADIATION PHYSICS

The radiation research program of the Bureau is directed toward meeting

technical needs in three general areas: radiology, nuclear science and technology, and radiation processing. For example, medical radiologists are requesting improved accuracy in the determination of source output and

absorbed dose. Since the calibration of clinical instruments is usually two

steps removed from the national standard, and since the transfer instruments

presently available have rather low precision (maximum effect of random

errors being of the order of 1 percent) , it is desirable to increase the accuracy

of the national standards. The NBS transfer instrument that is now used

for national and international comparison has an accuracy of 0.2 percent,

and extensive research efforts continue in this area. Demands from research workers for more accurate cross sections and for

more information about the nature of the interaction between radiation and

materials have resulted in an expanded program in these areas. In addition,

research laboratories require radioactivity standards accurate to within 1 per- cent; such accuracy is difficult to attain but is being provided with special

effort. Increased applications of radiation in industry for such purposes as preservation of foods, crosslinking of polymers, sterilization of sutures, and activation analysis have created a need for improved standards and dosimetry at high radiation energies and at high dose levels. Industrial applications re- quire measurements somewhat less accurate than those required for medical

or nuclear research applications, but beams whose intensity is usually of the

order of kilowatts of radiation power create severe measurement problems.

Considerable effort is currently being applied to the design and construction

of equipment which will be used to implement an enlarged research program

in the new laboratory facility at Gaithersburg, Md. Sources with higher

intensity, such as the NBS 100-Mev linear accelerator (Linac) and the 1.5- and 4-Mev direct accelerators which will become operational in 1964, will

make it possible for the Bureau to meet the increased demands for basic

experimental data, improved standards, and refined measurement techniques.

78
X-Ray and Gdmma-Ray Dosimetry

Cavity Chambers. Instruments used as laboratory standards for X- and

gamma-ray measurements by medical institutions, research laboratories,

manufacturers, atomic energy installations, the Military, and Civil Defense,

are calibrated by comparison with the Bureau's standard instruments. The

accuracy requirements for these calibrations have been steadily increasing.

Close agreement between NBS standards and those of other countries is also

important. Accordingly, improvements have been made in the Bureau's

X-ray free-air-chamber standards, in the calibration accuracy of gamma-ray

beams, and in diaphragm sytsems for evaluating stem corrections in certain

types of radiation instruments.

Photographic Dosimetry. Work continued on extending photographic

dosimetry to exposures of 1 milliroentgen (mR) or less of high-energy X- and

gamma-radiation. Post-exposures to 620-millimicron infrared radiation,

chemical treatment of the films, and special development techniques extended

the range downward by close to a factor of ten. Microphotographs showed

that this extension is achieved by an increase in grain developability (larger

number of grains developed at any given exposure), an increase in the

projected area of the grains, and a general change in grain shape.

Further experiments were performed on films that had been exposed to two widely different rates of gamma radiation and, after development in a surface developer, had shown marked reversal and re-reversal effects. Most

of the work on these films during the past year was done at the Armed Forces

Institute of Pathology (Biophysics Branch). The measured quantities, i.e., developed silver per unit density (the photometric equivalent), mass of developed silver per grain, and density per grain (proportional to the densitometrically effective projected grain area), were studied for both intensities as a function of exposure. Anomalous behavior was found for the number

of grains in the ascending branch of the density-versus-exposure curve obtained with high intensities, and for the photometric equivalent at the re- reversals for the very highest exposures both with high- and low-intensity

radiation. Conclusions were drawn from these findings concerning the cause

for the rate dependence of the maximum density attainable, and for re-reversal.

A review paper on the use of photographic film for personnel dosimetry was presented at the Symposium on Personnel Dosimetry Techniques for

External Radiation, held in Madrid under the sponsorship of the European

Nuclear Energy Agency.

Solid State Dosimetry. The investigation of the response to X-rays of

silicon radiation detector cells of the diffused p-n junction type, when operated as photodiodes and photovoltaic cells, was continued. Different cells of the same type were investigated and methods of measurements were improved in order to provide increased accuracy. The temperature dependence of the photocurrent produced by X-rays was measured between 25 and

50 °C and found to be similar to that observed for photocurrents produced

in silicon photocells by visible light. Measurements of the energy dependence of the generated photocurrent were extended to moderately and lightly

79
filtered X-rays of half-value layers between approximately 0.07 mm and 16.0

mm aluminum. Preparations have been made for comparative measurements

of the response to X-rays of silicon radiation detectors of different types.

Response of Silicon Charged Particle Detectors at Low Temperatures. A program to investigate and develop solid state counters for nuclear physics experiments is under way. Recent measurements were carried

out to investigate a suggestion that Li-drift detectors should function as well

near absolute zero as at elevated temperatures. The results of two dissimilar

experiments, designed to eliminate contact anomalies at low temperatures,

indicate that the response exhibits a sharp decrease at a temperature of about

30 °K. Subsequent measurements with a silicon surface barrier detector

of 3000 ohm-cm resistivity show that the anomalous region for this relatively

undoped silicon extends from about 17 to 25°K. Corroborative experiments

and experiments to confirm recent theories as to the physical origin of the

effect are in preparation. Beyond the interesting solid state physics implied

by this work, an appropriately doped silicon detector and beta-emitter with

a simple charge-sensitive preamplifier and integral discriminator may have

possibilities as a very accurate and convenient secondary temperature

standard.

Radioactive Sources

Scattered Spectrum of Water-Shielded Sources. Measurements have

been made to determine the gamma-ray spectra produced by the Bureau's

two water-shielded cobalt 60 radiation sources. A demountable model was

constructed having separate radioactive parts in the form of thin wires. A

series of ion chamber measurements made with the model in different stages

of assembly gave the scattered intensity contributed by the various component parts and by the water. The scattered intensity was found to be 21

percent of the total, and the spectral distribution approximately the same as

that of singly scattered primary photons. This information, permitting

more accurate estimates of absorbed dose delivered by these sources, will

make feasible an experimental comparison of calorimetric and ionization

methods of radiation dosimetry.

Standards of Radioactivity. In the past year the sum of standards

sold and calibrations performed exceeded 600; several international camparisons have been carried out; at least two new methods of measurement

have been developed; and a material contribution has been made to the

development of the radiation standards laboratory of the Bureau Inter- national des Poids et Mesures by sending a staff member to work at Sevres

for six months. An iodine 125 solution standard and a cerium 139 gammaray point-source standard have been developed and a new series of krypton

85 standards has been issued. Intensive investigation of the accuracy of

mass-spectrometric analyses of carbon 14 in carbon dioxide, carried out in

conjunction with the Applied Analytical Research Laboratory, resulted in the

NBS value of the half life of carbon 14 being reduced 15 years to 5745 ±50

years, a change which is less than one-third of the estimated probable error. This determination brings the NBS value into close agreement with the

80
Cambridge average of British, Swedish, and United States results, adopted

in July 1962, of 5730 ±40 years.

The two new methods of measurement which are of note are (1) the use

of silicon at temperatures below 4.2 °K for the detection of beta particles,

and (2) the use of Auger electrons to indicate the source self-absorption

for X-rays in the preparation of standards of the electron-capturing nuclide

iron 55.

The low-level radioactivity program has made considerable progress,

and intercomparative measurements have been satisfactorily carried out on

samples of strontium-yttrium 90 and iodine 131 in water distributed by

the U.S. Public Health Service, and of iodine 131 in evaporated milk

distributed by the U.N. International Atomic Energy Agency. A new

method has been developed for the quantitative analysis of low levels of

uranium in water and in urine by ion exchange without lengthy preparation,

thereby reducing the time required for a measurement from four to two

days.

Model used to determine the gamma-ray spectra of the Bureau's two water- shielded cobalt-60 radiation sources. Pencils with tapered ends contain radioactive material; flat-ended pencils are solid dummies. Cavity ionization chamber in center of model measures intensity of radiation. (See p. 80.)

81
Radiation Interaction With Matter. Investigations have been made

of some of the important processes involved in the interaction of electrons

with matter in the energy region from 50 to 500 kev. These processes

include electron single scattering with and without atomic excitation. The

experimental studies were carried out with the NBS 500-kev electron accelerator and with magnetic and scintillation spectrometers. The experimental results show good agreement with available theoretical predictions

for the process of scattering without atomic excitation. However, for the

process of scattering with atomic excitation, there are large discrepancies

between experiment and theory which are attributed to the approximations

used in the available theory.

Radiation Interaction with Nuclei

The Interaction of Bremsstrahlung with Alined Nuclei. During the

last five years, a series of experiments has been carried out to study the

interaction of high-energy photons with nuclei known to have large intrinsic

deformation's (i.e., nuclei with large intrinsic quadruple moments) . Studies were made of both the scattering and the absorption of photons by these

nuclei. The analysis of these data indicated such nuclei probably have a

large intrinsic tensor polarizability. During the last year and one-half,

this part of the polarizability of the holmium nucleus has been studied directly

in an experiment designed to show that the nuclear absorption cross section

in the giant resonance energy region depends upon the orientation of the

nucleus with respect to the photon beam. The experiment has been carried

out in collaboration with a group from the Low Temperature LaboratoryHolmium nuclei are alined along the c-axis of a single crystal of holmium ethyl

sulfate by the Bleaney method. The crystal, cooled to 0.03 °K by means of a continuously operating He3 refrigerator, can be rotated with respect to the

beam from the betatron.

The experiment consists of measuring the yield of photoneutrons from

the holmium ethyl sulfate crystal as a function of the orientation of the

crystal's c-axis with respect to the photon beam. This is done at a series

of six betatron operating energies between 10 and 20 Mev. At temperatures

above 4.2 °K, only slight asymmetries are observed in the yield of photoneutrons as the crystal is rotated. To a large extent these can be accounted

for by the slight geometrical asymmetry of the crystal. At 0.3 °K, considerably larger asymmetries are observed that can be attributed to the tensor

polarizability of the holmium nucleus.

Nuclear Matter Distributions as Determined from Neutral Meson Photoproduction. The major process contributing to neutural meson photoproduction near threshold leaves the residual nucleus in its ground state. Thus,

the process is completely coherent and exhibits strong nuclear size effects. In the Born approximation, these nuclear size effects can be represented by

a form factor. The form factor for tt° photoproduction is the same as that

for elastic electron scattering, neglecting nucleon size, except that the electron

scattering experiments observe the distribution of electric charge in the

nucleus, whereas the ir° photoproduction observes both protons and neutrons

82
Holmium ethyl sulfate crystal used to measure the dependence of the yield of

photoneutrons from holmium on the orientation of the nucleus with respect

to the photon beam direction. Nuclei were alined by cooling the crystal to 0.29 " K. (See p. 82.)

with equal weight and is thus a measure of the nucleon matter distribution.

By comparing the results of electron scattering and tz° experiments, it may

be possible to determine information about the relative distributions of

protons and neutrons in the nucleus.

During the last several years, a series of measurements has been made of

the photoproduction of ir° mesons from complex nuclei. The results of

measurements on elements carbon, aluminum, copper, cadmium, and lead

have indicated nuclear rms radii agreeing within the errors with those deduced from electron scattering experiments. The rms radii are determined

to within 2 X 10"14 cm. A series of measurements are currently in progress to study tt° photoproduction from the elements carbon, magnesium, aluminum, silicon, and sulfur

to improve the absolute accuracy of the measurements and to compare the

radii of neighboring nuclei. In addition, aluminum with a spin of 5/2

should be a very good element with which to investigate the possibility of

spin-dependent contributions to the tt° photoproduction. Preliminary analysis of data indicates that the elastic photoproduction process does not seem

to be dependent on the spin of the target nucleus. The data for aluminum

are not different (except for size effects) from the data obtained from magnesium and sulfur, both of which have a major isotopic abundance of spin

zero. A rough fitting of the data from magnesium, aluminum, and sulfur

indicates that the ratio of the nuclear matter distribution to the electric

charge distribution is constant to within the probable error of 2 percent.

An attempt is being made to obtain a sample of 0

18 water to make similar

measurements. This should be an especially interesting case since O18 con83
sists of a closed O

1 " shell with two rf-wave neutrons outside the closed shell. Neutron Time-of -Flight Technique. Measurements of the interaction

of high-energy neutrons with nuclei are useful both for investigation of the

parameters of nuclear models and for calculation of the shielding characteristics of bulk matter. An experiment has been performed to measure the

elastic and inelastic scattering cross sections, as a function of scattering

angle, of 14-lVTev neutrons on calcium. The experimental technique utilizes

measurement of the flight times of the scattered neutrons to determine their

energies; groups of neutrons having flight time differences as small as 1.5X10"° sec have been resolved. Theoretical calculations of the elastic cross sections have also been carried out, using the optical model of the

nucleus, for a wide range of neutron energies. The experimental results

for calcium agree with the general predictions of the theory, but have also

confirmed small discrepancies previously reported.

The target area for measurement of the scattering of 14-Mev neutrons. The

neutrons are produced on a target at the center of the thin-walled sphere. The

counter at left center records the time at which a neutron leaves the target, and

the counter at the right rear detects this neutron after it has scattered from the

small cylindrical scatterer in the right foreground. (See p. 84.)

84
Previous Bureau investigations using y-rays have demonstrated the large

deformation of the holmium nucleus. The neutron time-of-flight equipment

that has been developed will permit further investigation of this deformation

using 14-Mev neutron scattering from alined holmium nuclei.

Particle Interaction Theory. More than 30 elementary particles and

resonances have been found. The classification and correlation of the properties of these particles—masses, spins, parities, moments, and decay widths

are among the most challenging problems of modern physics. Interestingly

enough, the methodology used in attacking this problem of elementary particle spectroscopy is quite analogous to the now familiar techniques of nuclear

and optical spectroscopy.

The introduction of unitary symmetry (SU3) in the octet model or "eightfold way" to describe the strong interactions between elementary particles

has recently been proposed and its consequences are now being explored.

Unitary symmetry is a generalization of isospin symmetry which also in- cludes the strangeness quantum number. In the octet model, the spin=V2

baryon, i.e., the neutron, proton, 2", 2°, 2

+

, S", E°, and A particles are considered as members of a unitary multiplet just as the neutron and proton

are the two members of an isospin multiplet. Similarly, the pseudoscalar

mesons, K°, K+

, iT, tt°, ir+, -q, K~, K° are also members of a unitary multiplet.

Particular attention has been paid to the formulation of possible tests of

the theory by examining reactions of the type

meson + baryon—»baryon resonance + meson

and

meson + baryon—^baryon resonance + vector meson.

The role of the gamma-ray in the eightfold way has also been investigated

in detail. Quantitative predictions about processes like the photoproduction

of baryon resonances and their electromagnetic decays have been formulated.

Preparations for New Linear Accelerator. Progress continues in

the design and construction of the NBS linear accelerator (Linac). Tests

of the first prototype accelerator section are complete and have been valuable

in fixing the final production phases of the new machine. Completion of

the accelerator is expected in the fall of 1963 and installation in the new

laboratory at Gaithersburg, Md., in the spring of 1964. Research with the

accelerator will meet the increasing need for basic data and physical measure- ment technique developments in the use of intense high-energy electron

beams in radiography, radiology, nuclear physics research, and radiation

processing of materials.

Linear Accelerator Theory. Existing theories of linear accelerator performance have always assumed that the Linac waveguide is a broadband

device without dispersive properties. In reality the Linac waveguide is highlydispersive and has a passband only a few megacycles wide. Substantial

fluctuations in th rf power transmitted by the waveguide of the prototype of

85
the NBS accelerator have led to the development of Linac theory to include

these dispersive effects, and theoretical calculations successfully predict the

observed fluctuations. The theory has been extended to include dispersive

effects in the heavily beam-loaded Linac, and a number of new predictions

have been made concerning Linac behavior. These predictions are of considerable importance to many linear accelerators being considered at the

present time. Similar calculations have been made of waveguides being

considered for the very large linear accelerator being constructed at Stanford

University. When the NBS linear accelerator is available, an attempt will

be made to confirm other interesting predictions of these calculations.

Heavy-Ion Source for Magnet-Optic Studies. A 400-kev krypton ion source has been developed to study the detailed performance of beam deflecting magnets and of magnetic spectrometers. Since a 400-kev krypton

ion has the same momentum as a 250-Mev electron, this will allow detailed

study of magnets over the range of interest on the NBS Linac.

The present performance of the ion source is sufficient for detailed study

and ray tracing of individual magnets. Further refinements will be necessary

before it can be used to test entire magnet systems where the total flight path

in the system approaches 150 feet. The first bending magnet of the NBS beam-handling system has been

delivered and measurements of the deflecting properties of this magnet are being made.

High-Current Beam-Handling Problems. The very high beam current

of the NBS Linac poses unique and severe problems of metal fatigue and heat

dissipation in collimating and stopping the beam. A number of measurements

have been made in collaboration with High Voltage Engineering Corporation

and Yale University on these problems, using the Yale Linac. The results of

these measurements have demonstrated the extreme importance of the pulsed

nature of the Linac beam on metal fatigue and on cooling behavior and have

led to design information which will be used in developing the NBS beamhandling system.

Equipment for Use With Linac. The current effort in the Linac research

program is to develop major long-lead-time pieces of experimental equipment.

It is hoped to have this equipment developed and on hand at the time the

Linac is available. The major items being developed are (1) a magnetic

spectrometer for performing elastic and inelastic electron-scattering experiments, (2) a magnetic spectrometer for detecting heavy charged particles,

protons, deuterons, alphas, etc., (3) equipment for producing beams of

positrons and monoenergetic photons, (4) facilities and equipment for studying (y, n) reactions using nanosecond time-of-flight techniques, and (5)

equipment and techniques for accurate and convenient electron beam

monitoring.

Data-Logging and Data-Handling System for the Linear Accelerator.

A detailed examination has been made of the needs for data-logging and

data-processing equipment for the experimental programs using the linear

accelerator. This survey has indicated that there are major scientific, tech86
nical, and economic advantages to the use of a small on-line, general-purpose

computer for these data-logging problems.

As there exist satisfactory commercial computers for these applications,

the major problems are the development of various types of input and display

equipment and program organization of the computer.

An examination of the experiments which would use this system reveals

that a complete data-logging program can be accomplished by the use of one

or more of a small number of basic building-block input subsystems. The

logical design of these subsystems and detailed circuit drawings are nearly

completed. Hardware to construct a portion of the input system is ordered

and construction began in July 1963.

The computer chosen for this system, SD-920, is on order and delivery

is expected in September 1963.

Considerable effort is now going into an investigation of the coding and

programming problems which will occur with simultaneous usage of this

system by several experimental groups and in procedures for rapid and

convenient program control to meet the variable and uncertain needs of

experiments. While these are not easy problems satisfactory solutions seem

to be feasible.

It is hoped that this data-logging system will be in useful operation on

experiments in approximately one year.

2.1.8. LABORATORY ASTROPHYSICS

The Joint Institute for Laboratory Astrophysics (JILA), established in

April 1962 on the University campus at Boulder, Colo., is a collaborative

effort of the Bureau and the University of Colorado. The Institute provides

a center for both research and advanced training in areas of physics and

astrophysics which provide the scientific basis for meaningful measurement

in very hot gases. Here, scholars in many specialties are given the opportunity to exchange ideas and data. The staff is composed of appointees

of both the Bureau and the University of Colorado.

Astrophysics is the application of physics to problems of astronomy. At

JILA, theoretical rather than experimental work is emphasized, with greatest

effort concentrated in those areas of theoretical astrophysics which provide

the physical understanding for fundamental processes in stellar atmospheres.

This effort is closely related to low-energy physics.

In atomic physics, heaviest emphasis was placed on atomic, electronic,

and ionic collision processes. Also studied were optical resonance phenomena

and lasers, ultraviolet and visible atomic spectroscopy, and continuous absorption coefficients of ions, and ionic mobilities. In astrophysics, data from the 1962 solar eclipse were analysed, and work

on solar flares was continued. Theoretical techniques to describe departures

from local thermodynamic equilibrium of a gaseous atmosphere are under

development. Attempts are underway to determine helium abundance in the

solar chromosphere and the chromospheric structure of certain types of stars.

714-691 O—64 7 87
Physics of Atomic Collisions. The mobilities and diffusion coefficients of three species of helium ion were measured with high precision,

and the rate coefficient for the formation of helium molecular ions in threebody collisions was also determined. This work is particularly interesting

because it appears to conflict with conventional theoretical limits on the

molecular helium mobility. Similar measurements were made in neon. Experiments being planned include photodetachment of negative ions of molecular oxygen under conditions of thermal equilibrium at room temperature.

With AEC support, a detailed experimental study of dissociative ionization

of hydrogen molecules by electron impact was completed. Specifically, the

kinetic energy distribution of protons from the dissociating ions was

measured and—for the first time—agreement obtained with theoretical prediction. More importantly, the angular distribution of the protons was determined with respect to the ionizing electron beam direction, and this distribution was shown to be highly anisotropic, as predicted. This result

proves that most of the values of cross sections for collisions of dissociating

molecules reported in the literature should not be considered correct, since

the geometries of these experiments usually were predicted on the assumption

of isotropy. Studies on angular distributions in oxygen and nitrogen are continuing.

The photodissociation of the positive ion of molecular hydrogen is being

studied in a cross-beam experiment also supported by AEC. The integrated cross section appears, in general, consistent with theoretical expectation, al- though the spectral distribution of the cross section may be anomalous.

An experimental study of the elastic scattering of monoenergetic electrons

from atomic hydrogen in crossed beams is in progressAnalysis of data taken earlier on the photodetachment cross section

of the negative iodine ion was completed with financial support from ARPAONR and in collaboration with the Atomic Physics Division with the result

that the binding energy of this ion is now known to an accuracy of 3 mv.

In addition, comparison with shock-tube data of other experiments provides

insight into the unusually small depression of negative-ion binding energies

in dense plasmas. Concurrently, theory for the threshold behavior of negative ion photodetachment, including the effects of polarization, is being

developed by one of the JILA Visiting Scientists with a stipend from the

University of Colorado's NSF Grant. The experiments on the negative

iodine ion will provide a critical test of the theory when the effects of the

iodine quadruple moment have been included in the theory.

The most accurate cross-section calculation for the negative hydrogen

ion bound-free absorption coefficient yet determined theoretically was completed, and it is in excellent agreement (within a few percent) with the

results of precise experiments. Meanwhile the Bureau is assisted in this

effort by a CU contract from AF Special Weapons Center involving detailed calculations of the free-free absorption coefficient which are being

made using these accurate wave functions. A new calculation of the cross

section for ionization of the negative hydrogen ion by electron impact shows

88
that the previous result was too large. An attempt to measure this cross sec- tion is planned.

Also in progress by JILA Visiting Scientists are a calculation of the cross

section for ionization of atomic hydrogen by proton impact and a study of

the ionization of Fe xiv by electron impact.

This two-quantum photodetachment probability for negative iodine and

other ions was calculated. A giant-pulse ruby laser makes possible an

experimental measurement of this probability using the photodetachment

apparatus.

Astrophysics. Work continued on the development of theoretical techniques for describing a gaseous atmosphere, departing from local thermodynamic equilibrium, in which aerodynamic phenomena provide an energy

source but are too small to provide a momentum source. An attempt was made to extend this work to treat the solar corona and the rocket ultraviolet

spectrum of the sun. The chromospheric spectra from the very successful 1962 Solar Eclipse

Expedition to New Guinea were analyzed in collaboration with astro- physicists from the High Altitude Observatory at Boulder, Colo., and the

Sacramento Peak Observatory at Sunspot, N. Mex. A serious discrepancy

in the literature concerning the temperature of solar prominences has been

explained.

Two other investigations are nearly complete: a study of the excitation

of helium lines in the solar chromosphere leading to a determination of the

helium abundance, and a study of proton kinetic energy distributions in

coronal-loop solar prominences.

A set of observations of line profiles of the calcium H and K lines in

spectra of G, K, and M-type stars were completed at Mt. Wilson Observatory

near Pasadena, Calif., in collaboration with the UCLA Department of

Astronomy. These data will be interpreted in an attempt to discern the

chromospheric structure of such stars. Work on solar flares was continued by a JILA Visiting Scientist (NSF).

x\n analysis of the spectrum of the September 2, 1960 flare was completed,

and some of the 1962 eclipse data were reduced.

An unusual photoelectric instrument was developed for measuring the

relative strength of solar chromospheric continua on both sides of the

Balmer discontinuity. The equipment was used in Alaska during the July 20,

1963 solar eclipse.

Resonance Physics. The possibility that optical pumping by sunlight occurs naturally in the sodium of the earth's upper atmosphere was investigated with the result that the effect appears negligible except in the case

of artificial sodium releases from rockets at higher altitudes. A theoretical

investigation was made of hydrogen atom spin exchange collisions, with

applications to the operation of a hydrogen maser. Optical pumping of

rubidium vapor in the presence of a high-pressure buffer gas was observed

experimentally using natural sunlight.

89
A giant-pulse ruby laser, producing about 1 joule and up to 50 Mw of

monochromatic light, was developed for the purpose of studying nonlinear

interactions of atoms and matter with radiation. The feasibility of measuring the two-quantum photodetachment of negative iodine ions has been

studied. A fluorescence experiment on anthracene has been carried out in

collaboration with the Radio Standards Laboratory, in which two photon

processes give a fast fluorescence as well as the previously observed delayed

fluorescence due to exciton-excitor collisional recombinations. Preliminary

work on detection of high-frequency beats from two closely spaced gas laser

lines in the infrared was started.

Work was begun on an apparatus to measure the acceleration of gravity

using an interferometer (one plate of which is the falling object) together

with a gas laser light source. In addition to the importance of this meas- urement to the field of standards, possible variations in the gravitational

field strength (which could be of cosmological origin) might be detected

with the high precision obtainable with this new technique.

Plasma Physics, Statistical Physics, and Aerodynamics. An ex- perimental study was made of the structure of self-ionizing hydromagnetic

shock waves in a magnetic field. Experiments are planned to apply hydromagnetic shocks to the study of solar flares. Data Center on Atomic Collision Cross Sections. The Data Center

completed its survey of all literature reporting cross sections for twobody collisions involving a free electron, and is currently providing bibliographic searches for the general scientific community. The material is coded by subject matter as well as by normal reference to author, journal, etc. Preparation for the publication of the complete bibliography by subject

classification is in progress. The Data Center has been jointly financed

by ARPA, ONR, and NBS.

2.2. CHEMISTRY AND PROPERTIES OF

MATERIALS

2.2.1. ANALYTICAL AND INORGANIC CHEMISTRY

Recent scientific and technological advances require new, accurate data on the properties of materials. To help fill this need, the Bureau conducts

intensive investigations to determine the physical and chemical properties

of both common and rare elements and compounds. Such investigations

require new and improved analytical techniques as well as tried and proved

methods. New instrumental analyses hold promise for improved analytical

speed, accuracy, and precision.

Consultant services are available to Government and industry alike on

diverse subjects such as radioactivity (the Bureau participates in the Atomic

Energy Commission's standards program) , the compilation of scientific and

technical data, the measurement of physical constants and chemical properties of materials, and the preparation of standard samples. The Bureau also

90
issues standard materials of known composition for metallic and nonmetallic

inorganic compounds as well as standards of composition for some organic

materials.

New activities include a study of inorganic synthesis and reaction rates, an analysis of trace impurities and their effect on the properties of materials,

the preparation of standards required for determining atomic weights by

isotopic abundance measurements, and a study of optical and X-ray spectra

in crystals at low temperatures.

Atomic Weight Redetermination. Atomic weights of several ele- ments are being redetermined with increased accuracy by employing mass

spectrometric methods of comparing natural materials with reference standards prepared from concentrates of individual isotopes. Extracting a given

element from a wide variety of natural sources in order to establish a normal

value for its atomic weight is an important part of the program. The work

of redetermining the atomic weight of copper is nearly complete, and preliminary work for redetermining the atomic weights of other elements,

especially bromine, is now in progress.

Reactivity of Coordination Compounds. Studies of coordination

compounds are being conducted to determine the role of these substances as

catalysts and reaction intermediates, and to investigate their application to the synthesis of new compounds. As part of these studies, isotopically en- riched boron compounds are employed to study the displacement of one such

compound from a complex by another compound. In addition to providing

information about the reactivity of boron coordination compounds, these

studies suggest several possibilities for solving problems of synthesis in boron

chemistry.

Thermodynamics of Aqueous Solutions. Studies of thermodynamic

constants of acids, bases, and salts and their interactions in solution provide

basic knowledge essential for improving and extending existing methods of

measurement. A new technique, isopiestic vapor-pressure measurements,

when applied to a water-urea-sodium chloride system yields free energies or chemical potentials of each of the three components at all compositions up

to saturation; that is, up to about 47 percent urea and 14 percent sodium

chloride. From the free energies obtained, the effect of added urea on the

solubility of sodium chloride and the effect of added sodium chloride on the

solubility of urea can be calculated. The composition of the solution at the

point of mutual saturation (where the solution is saturated with respect to both urea and sodium chloride) is then readily derived.

pH Scale for Alcohol-Water Solvents. Because of its reproducibility, determining the pH of alcohol-water solutions found with commercial

electrometric pH equipment is an important control variable in many industrial and research operations. Determined in the conventional way, pH numbers are interpreted in terms of hydrogen ion concentration or activity only

when the solvent medium is pure water. A scale of pH (designated pH*)

for methanol-water and ethanol-water media has been proposed, its practicability has been demonstrated, and procedures for assigning standard pH*

91
values to reference solutions have been devised. The pH* determined ex- perimentally bears a simple relation to dissociation constants and other

thermodynamic quantities in the same medium and, as such, should have

wide application in many branches of chemistry and biology. Furthermore,

scales of pH* can be established for many other solvent systems by similar

procedures.

Dielectric Cryometry for Determining Purity. The purity of a compound can be determined by measuring the temperatures corresponding

to particular solid-liquid ratios while the compound melts or freezes. In a method called dielectric cryometry recently investigated by the Bureau, the

solid-liquid ratio is determined by measuring the change in dielectric coefficient, and by simultaneously measuring corresponding temperatures during the melting process. The data collected indicate a change in an intensive

property of the material, and samples of only 4 to 10 milliliters are required.

Purity measurements, made on a number of compounds with diverse dipole

moments and polarizabilities, resulted in a precision of 0.005 to 0.0004 mole

percent. Refinements in the design of the apparatus may increase the

precision still further.

Argon Shielding in Spectrochemical Analysis. Spectrochemical

analysis of high-temperature alloys is difficult because given elements volatilize at different rates depending on whether they are present in an iron-,

nickel-, or cobalt-base alloy. Standards for the same element in all three

Isopiestic vapor pressure measurements provide a new technique for measuring

the thermodynamic properties of aqueous solutions containing one electrolyte

and one non-electrolyte. The wire apparatus is used to close the covers on the

sample cups while they are still under vacuum in the dessicator. (See p. 91.)

92
Laser microprobe can perform a spectrograph^ analysis of a sample as small

as 50 microns in diameter. (See p. 93.)

types of matrix are therefore necessary. Shielding the specimens with argon

gas reduces the differences in volatilization rate and shows promise of re- ducing the number of spectrochemical standards needed for the routine

determination of the major constituents in high-temperature alloys.

Transition Probabilities. Transition probabilities are important to

analytical chemistry and basic spectroscopic research. Most transition probabilities determined to date have been for gaseous elements that are easily

introduced into an arc discharge. However, through exhaustive studies of

the properties of the gas-stablized arc, data for 105 lines in the spectrum of

neutral atomic iron have been redetermined. An analysis of the new data

has resulted in transition probabilities for neutral atomic iron more precise

than those obtained in three earlier investigations.

Laser Microprobe. A prototype of a commercial laser microprobe is being investigated and, with certain changes, is expected to be a useful

tool in microanalysis. The instrument permits spectrographic analysis of

samples as small as 50 microns in diameter. A brief, high-energy pulse

93
of light from a ruby laser, focused through a microscope onto the spot to be analyzed, is sufficient to volatilize the sample as a jet of vapor. This

vapor jet, passing through a gap between two graphite electrodes connected

to a large condenser, triggers a spark discharge which excites the elements

in the sample. The spectra characteristic of the light from the spark dis- charge are recorded with a spectrograph in the usual way. Almost all the elements in the periodic system may be excited simultaneously. In addition to its application to the analysis of small samples, segregates, and

inclusions, the laser microprobe is expected to be valuable for studying highpurity materials. An advantage of the device is that it requires little or no

preparation of the sample prior to the analysis.

Solvent Effects on the Rates of Acid-Catalyzed Reactions. The

speed of chemical reactions in solutions is influenced by the nature of the

solvent, particularly when an acid or base takes part. For example, the

rate of a reaction, catalyzed by acid, may change because of the effect

the solvent produces on the acidity of the medium or because the free

energy of activation is altered. The rate of hydrolysis of acetal, a typical

acid-catalyzed reaction, was studied in solvents prepared by mixing water

with varying proportions of acetone, dimethylsulfoxide, dimethylformamide,

or A^-methylpropionamide. Replacement of half of the water by acetone

caused the rate to fall to y15 its value in pure water; and similar amounts

of dimethylsulfoxide, dimethylformamide, and A'-methylpropionamide re- duced the rate to %5 , and %00' respectively. The mechanism of the

solvent effect is still not clear, but the change in rate does not appear to be

linked closely with the change of either the dielectric constant or basicity of

the medium.

Acidities of Dinitrophenols in Benzene and Water. Quantitative

comparisons of the behavior of acids and bases in two dissimilar solvents

like benzene and water furnish valuable insight into the mechanism through

which solvents affect chemical reactivity- Six dinitrophenols, all having

the same composition but differing in atomic arrangement, have ionization

constants in water ranging from approximately 10"4 to 10"7

, as shown by

careful spectrophotometry measurements of the acid strength. However,

the relative order of acidic strengths in benezene differs from that in water.

Information of this type is helpful in interpreting the behavior of dinitrophenols in nonaqueous solvents, where they are finding increased use as reference acids.

Crystal Growth From Mixed Solvents. Solvent effects on the growth

of large crystals from solution have recently been illustrated in experiments

with oxalic acid. For example, anhydrous oxalic acid crystallizing from

glacial acetic acid solution gives inferior single crystals containing inclusions

of the mother liquor. However, the addition of small amounts of water

added to the solvent produces single crystals of greatly improved quality,

and nucleation is inhibited. A phase study of the system oxalic acid-acetic

acid-water at 50 °C showed that anhydrous oxalic acid is the stable solid

phase in equilibrium with aqueous acetic acid solutions containing up to

94
5.2 percent water. In other experiments, single crystals of oxalic acid

dihydrate, difficult to grow from water solution, were of good quality when

grown in acetone-water mixtures.

Studies of Crystal Symmetry. A general study on the effect of homogeneous strain on crystal symmetry has shed light on the problems of internal

friction due to point defects, second-order piezoelectric coefficient, secondorder transformations, solid solution effects, and crystal field phenomena;

and has suggested procedures for space-group determinations from ambiguous

X-ray patterns. The treatment is general and applies to all crystalline solids

with any type of strain.

X-Ray Analysis of Crystalline Solids. A high-voltage (150-kv) , fine- focus X-ray apparatus with a special collimating slit has been procured to obtain X-ray diffraction diagrams of single crystals up to 1 in. thick. Conventional diffraction procedures can be applied only to thin crystals or to surface layers of specimens. The X-ray unit has also been used to obtain

diffraction patterns of single crystals enclosed by protective containers of

Pyrex glass.

f#'/' + ' S

1

\

" N ^ - '

tf '

x N * *

v . ~

X-ray diffraction pattern of germanium single crystal obtained with high-voltage

fine-focus X-ray unit. This special equipment can be used to explore single

crystals up to 1 inch thick. (See p. 95.)

95
Control of Fractional Distillation. Variations in ambient temperature, barometric pressure, and line voltage afTect the efficiency of fractional

distillation in the laboratory, principally because these variations cause changes in the flow rate of vapor from the still pot to the column. An auto- matic controller, consisting of a thermistor sensing device in the vapor line,

automatically regulates the heat input to the still pot, thus maintaining a constant flow of vapor to the column. With the use of this device, the

fractionation process can operate at an appreciably higher, uniform efficiency

throughout the distillation.

Moisture Determination. A gas chromatographic method was developed for determining water content in various materials, particularly in

grain. A solution formed by extracting the moisture from the material with

methanol is injected into a commercial gas chromatograph. Methanol and

water curves are recorded on a strip chart by the gas chromatograph and

the relative areas under the methanol and water peaks are used to calculate

the moisture content. The method is precise and accurate to 7 parts in one thousand, corresponding to an accuracy better than 0.1 percent of the

water content of a typical grain containing about 14 percent moisture.

2.2.2. PHYSICAL CHEMISTRY

The Bureau conducts a broad program of basic research in physical chemistry. The primary objective of this program is the development of an understanding of the molecular basis for macroscopic properties and processes.

Particular emphasis is placed on (1) the analysis of relatively complex

reactions into elementary molecular processes, (2) the development of the

energetics of simple chemical reactions, and (3) the determination of ac- curate structural parameters of reactive molecular species. Research is con- ducted in such areas as the kinetics of very fast reactions at high temperatures,

the photosynthesis of labeled organic molecules, the structure of reactive

molecules which are stabilized in inert matrices at cryogenic temperatures,

the interaction of high-energy radiation with organic molecules, the determination of absolute isotope abundancies, the fundamental processes related

to surface catalysis, the structure and stability of short-lived species occurring

in high-temperature combustion processes, and reaction mechanisms in synthetic organic chemistry. Supporting theoretical studies are made in the

general fields of relaxation and transport phenomena, mechanisms of ex- citation and deactivation of simple molecules, energy distribution in and

dissociation of excited organic molecules, and molecular orbital calculation.

Considerable effort is directed to the development of special instrumentation

and associated techniques of measurement.

The need for critically evaluated fundamental data continually increases

at an accelerated rate. During the year a new project was initiated with the

objective of developing a simple system for collecting, coding, retrieving,

and assessing basic data in selected areas of physical chemistry. This project

represents an initial phase in the establishment of a special data-processing

activity at the Bureau.

96
Thermochemistry. During the past year the Thermodynamic Data

Group commenced a full-scale revision of NBS Circular 500, Selected Values

of Chemical Thermodynamic Properties, which contains best values of the

heats and free energies of formation of inorganic substances and some or- ganic compounds for which data were available at the time of publication

(1952). The current revision will take into consideration all available data

through 1961. This program on compilation of standard reference data

in the area of chemical thermodynamics has been a continuing part of the

Bureau's activities since 1940, with assistance from the Office of Naval

Research and the Atomic Energy Commission.

Recent experimental developments have been in connection with the design

and construction of two new high-precision calorimeters. An adiabatic

solution calorimeter which has a platinum reaction vessel and which can be

operated at temperatures to 100 °C will be used for measurements of the heats

of solution of refractory oxides and other relatively insoluble materials. The

assembly of this apparatus is complete and preliminary tests will be started soon. An adiabatic rotating-bomb calorimeter is also under construction. This

bomb consists of layers of silver and stainless steel, with an internal liner of

platinum. The bomb and jacket have been built, and construction of the

mechanism to rotate the jack, bomb, and adiabatic shield is now in progress.

Kinetics of Ion Decomposition. Certain unimolecular ion decomposition processes are readily observable in a magnetic sector mass spectrometer.

These include processes whose decomposition rates are of the order of 106

sec

-1

. The occurence of such slow decomposition processes in small polyatomic ions is of considerable theoretical interest. Recently, such processes

have been observed in ionized molecules of hydrogen sulfide and completely

deuterated methane. The substitution of various hydrogen isotopes produced pronounced effects on the occurrence of such processes. With deuterated methane, substitution of one or more hydrogens for deuterium in

the ion completely suppresses decomposition. Another study performed with

this mass spectrometric technique has given useful information on the problem of energy equilibration in excited polyatomic ions. It was found that

the mode of decomposition of an excited ion was independent of its past

history. This result supports the validity of the quasi-equilibrium theory of mass spectra.

Field Emission. Recent field-emission studies on the adsorption of

carbon monoxide on tantulum and niobium reveal the complexity of the

process. It has been found, for example, that there are at least three

binding energy states for chemisorbed carbon monoxide on tantalum, and

at least two for carbon monoxide on niobium. In general, the similarity

found for the adsorption behavior of carbon monoxide on these two metals

is very pronounced. There is no detectable difference between adsorption

by niobium in the superconducting as compared to the normal state. High-Temperature Microwave Spectroscopy. A microwave spectrometer which can be operated at temperatures up to 1000 °C has been

97
The rapid and homogeneous heating of gas samples by shock waves provides a powerful tool for the study of fast reactions at high temperatures. (See

P- 99.)

constructed in a program supported by the Advanced Research Projects

Agency. This instrument permits the extension of powerful microwave

techniques to the identification and structure determinations of molecules

and radicals which are present in high-temperature systems. There are numerous problems in high-temperature chemistry for which important

information can probably be obtained by this technique. Spectra have

been detected and analyzed for such molecules as aluminum monoflouride

and aluminum monochloride, which do not exist at room temperature, but

which are important constituents, for example, in rocket combustion systems.

The microwave spectrum of lithium chloride vapor was also observed for

the first timeEnolization and Isomerization Reactions of Reducing Sugars.

Numerous investigations over the past 60 years have shown that reducing sugars in alkaline media undergo reversible enolization and that the

resulting enediols are intermediates in a variety of rearrangement, elimination, and condensation reactions. The use of recent tracer techniques

employing carbon 14 and tritium-labeled sugars makes it possible to follow

reaction paths, to measure rates of reaction, and to determine the proportions of products formed.

A broad study of the enolization reactions of the principal pentoses,

hexoses, and heptoses is now in progress. Striking differences have been

found in the rates at which the various sugars of an epimeric group are formed, and in the effect of various catalysts on both rate and course of

the reaction. For example, in rearrangements catalyzed by sodium hydroxide, D-glucose is enolized more rapidly than D-mannose, and the rate of

98
conversion of D-glucose to D-fructose is five times that of D-mannose to Dfructose. But when pyridine is the catalyst, the rates of enolization are re- versed, and the conversion of D-mannose to D-fructose is three times as rapid

as that of D-glucose.

Generally, the 1,2-enediol reverts to the corresponding ketose more rapidly

than to the epimeric aldoses. The 2-ketoses then yield both 1,2- and 2,3-

enediols. Relative rates of 1,2- and 2,3-enolization are being studied by

quantitative determination of the rearrangement products of 2-ketoses con- taining five, six, and seven carbon atoms. Heretofore, unknown 3-keto

sugars have been postulated as intermediate in the production of 3,4-enediols.

The recent preparation of crystalline D-manreo-3-heptulose has provided material for direct study of 3,4-enediols. On treatment with alkali, the new

compound gave D-gZaco-2-heptulose, by way of the 2,3-enediol; and, of even

greater interest, D-allo- and D-a^ro-2-heptulose. Formation of the last two

substances requires reversible 3,4-enolization followed by 2,3-enolization.

Cryogenic Surface Chemistry. The reactions of hydrogen atoms

with condensed olefins have been under continuing investigation to develop an understanding of chemical reactivity at low temperatures. This research

has led to a clarification of several aspects of the chemical and physical

processes involved, among which are the establishment of the position of

addition of the H atom, the effect of diffusion on the reaction products, and

the mechanism of the reaction after the initial step. An important result was the demonstration that, in the H atom addition to the butene at low

temperatures, cw-butene-2 is not formed. This finding permits a detailed

examination of the disproportion atom-recombination reactions of the s-butyl

radicals, starting with cis-butene-2 as reactant. Kinetic Isotope Effects. A convenient method was developed for

measuring isotope effects of tritium in reactions that yield water-L The

water-J is sublimed and the isotope effect is obtained from the ratio of the

molar radioactivity of the sublimed water to that of the initial reactant. This

procedure is being applied to the study of a wide variety of organic reactions.

Shock-Wave Studies of JJnimolecular Reactions. The rapid and

homogeneous heating of gas samples by shock waves gives kineticists a powerful tool for the study of fast reactions at high temperatures. A single-pulse

shock tube is being used to study chemical reactions in the temperature range

700 to 1500 °C. In such an instrument the passage of a reflected shock wave heats a gas sample to a high temperature; about a millisecond later, a

strong rarefaction wave drastically lowers the temperature, thus quenching

the various chemical processes after an accurately known time interval. Conventional analytical methods, such as gas chromatography, may then be used

to study the nature and extent of the reactions. Current work is concentrated on studies of simple unimolecular decompositions resulting in stable

molecules. It has been possible to extend the range of kinetic studies previously carried out at low temperatures and to impose a critical test on the

postulated mechanisms and rate constants. Useful data have been obtained

for the tert-hutyl chloride, bromide, and alcohol decomposition reactions.

99
Except in the case of alcohol the results confirm those of earlier studies which

used quite different methods, and give valuable evidence of the accuracy of

the single-pulse shock-tube technique.

Ionization Processes at Surfaces. The studies of ionization on re- fractory metal surfaces at high temperature have been extended to the meas- urement of the lifetimes of cesium, rubidium, sodium, and potassium ions on rhenium surfaces as a function of temperature. A general type of potential function with an attractive and repulsive term has been fitted to the

data, and trends with size of the positive ion have been determined. The

characteristics of the surface ionization process can now be predicted with

regard to both ion size and charge.

Polycyclic Ketones. Polycyclic ketones, derived from inositol by oxidation, bridge the gap between the cyclitols and certain biologically important phenols. Because of their reactivity, very few of these important

intermediates have been isolated. In a project sponsored by the Division

of Air Pollution, Public Health Service, it was found that the residue, after

nitric acid oxidation of myo-inositol and separation of known products, con- tained a new substance, shown to be D-L-#y/o-trihydroxycyclohexenediolic

acid. The substance, the enolic form of a diketo inositol, is readily oxidized

to a new trihydroxycyclohexanetrione. With basic catalysts, the acetate of

the enediolic acid can be aromatized and converted by hydrolysis to pentahydroxybenzene, an important substance not generally available nor

closely investigated. This synthesis opens up a promising area for study.

These crystals of D-manno-3-heptuIose monohydrate, the first pure crystalline

3-keto sugar to be prepared, will provide Bureau scientists with an opportunity

for direct study of this and related sugars. (See p. 100.)

100
Acetylation of the new trione under acidic conditions gave an unexpected

tricyclic condensation product, the chemistry of which is being investigated.

Vacuum Ultraviolet Photochemistry. The interaction of vacuum

ultraviolet radiation with various molecules is being investigated under

extremes of temperature and pressure in order to understand the chemistry

of fragments of molecules. The CH3 CH fragment has been found to decompose to give H2 and acetylene, as well as to rearrange to form ethylene.

The effects of energy of the exciting radiation can best be studied in vacuum

ultraviolet photochemistry by using pure, intense line sources. Source

technology has been advanced by studying emission of rare gas resonance lamps under varying conditions of temperature, pressure, filling gas, and

additives.

High-Temperature Surface Reactions. The increasing use of re- fractory metals in military and civilian technology requires considerable

understanding of the physical and chemical behavior of these metals. The

high-temperature surface reactions of chlorine and bromine with nickel represents an active area of investigation in which chemical kinetic effects are being studied. A highly successful technique has been developed in which

the products of reaction are sampled with a time-of-flight mass spectrometer.

The reaction surfaces may be either those of a single crystal or polycrystalline

material. The mechanism of the nickel-bromine as well as the nickel-chlorine

reaction has been established. In either case, the reactive monohalogen

species has been found to be an important product in the higher temperature

region. This work is conducted under the sponsorship of the Atomic Energy

Commission.

Radiolysis of Simple Hydrocarbons. The gas-phase radiolysis of

single hydrocarbons, at pressures up to the critical pressure, was investigated

with Atomic Energy Commission support. It was shown that, in all cases, the unimolecular decomposition of parent ions and of electronically excited

neutral molecules contributes to the formation of observed products. In

the radiolysis of propane at one atmosphere, the primary fragmentation of

the parent ion shows a good correspondence to the recently calculated 10~10

second breakdown pattern, while the modes of decomposition of the neutral

excited molecules are similar to those observed in the vacuum ultraviolet

photolysis. It has been firmly established that accurate relative rate constants of ionic reactions occurring at atmospheric pressure can be obtained,

so that radiation chemistry can now be considered as complimentary to mass

spectrometry in the study of ionic reactions. This has been especially

demonstrated by the following studies: (1) Determination of the relative

rate constants of hydride ion and proton transfer reactions between ethyl

and propyl ions and a number of organic compounds; (2) the study of the

reactions of CH5 + and H3+ with hydrocarbons to form carbonium ions. The

latter type of reaction, which has not yet been observed in the mass spectrometer, is of considerable importance in radiation chemistry because such reac- tions may be expected to occur between a large number of protonated parent

molecules and neutral molecules.

101
Standard Reference Data in Physical Chemistry. An investigation

of document retrieval systems which will assist in the review and critical

assessment of physico-chemical data is now in progress. A selected library

of documents—primarily reprints and reports-—is being coded by "descriptors" and accession numbers and filed as a deck of optical coincidence or peek-a-boo cards. At the present time this library amounts to about 3000

documents. No thesaurus of terms has been established, so the number of

descriptive terms is currently of the order of 20,000 words, including author's names. The present method of retrieval is manual flight screen and an over- lay grid), but a Microcite information retrieval machine, developed by the

Basic Instrumentation Laboratory, is being constructed. This system is designed to support a broad program for rapidly collecting and assessing data

in the physical sciences. The general approach consists in selecting narrow

areas of traditional fields of research, assigning reviewers who are acknowledged authorities in the prescribed fields, and providing the mechanical assist- ance required for document search and reproduction. Subjects for such critical reviews are selected from the major areas of physico-chemical research;

for example, chemical kinetics, mass spectroscopy, transport properties,

thermodynamics, molecular spectroscopy, radiation chemistry, and surface

processes. The reviews will include sets of critically evaluated data which are

internally consistent and which can be regarded as "best" values.

2.2.3. INORGANIC SOLIDS

The demand for nonmetallic inorganic solid materials capable of withstanding extreme environmental conditions constantly increases as scientific

and space technology advances. The Bureau provides data, techniques,

and reference materials to help solve measurement problems in this field of

research. Methods for producing and characterizing metallic oxides, glasses,

and inorganic nonmetallic crystals have been investigated and data on the

properties of many of these materials have been provided. Significant ad- vances were made during the year in developing techniques for studying

the physical properties of crystalline solids over wide ranges of pressure

and temperature.

Rare Gas Crystals. A deeper understanding of the mechanisms and

problems involved in growing large single crystals for industrial and scientific purposes may be gained by studying simpler substances first. Such

crystals are formed from the rare gases argon, krypton, xenon, and neon. In current Bureau experiments, argon and krypton crystals are grown near

the triple points of these elements, 84 and 116 °K respectively. These studies

correlate crystal size and shape, growth rate, temperature gradient, and

degree of supersaturated solution with theory, and show that large rare gas

crystals may be prepared and studied with many of the same techniques

used at higher temperatures on other substances. For example, etch pat- terns in polycrystalline argon at 77 °K have been studied to learn about grain

growth, recrystallization, and annealing; and have been compared to the

102
Surface of a thermally

etched polycrystal of

argon. The rare gases

form very simple crystals and so are more

readily studied to gain

a deeper understanding of the mechanisms

and problems involved

in growing crystals.

Diameter of the field

of view is 2 mm. (See

p. 102.)

same processes in metals, where these phenomena take place at much higher

temperatures.

Rare gas crystals are perfectly transparent in a broad spectral range,

from the infrared to the ultraviolet. Spectroscopic techniques are employed to show the location of small amounts of impurities within a crystal

lattice, how they get there, and how they diffuse. These impurities have

large effects on the physical properties of crystals.

Molar Volume of Solid Neon Isotopes. Solid neon, like other rare gas crystals, serves fairly well as a model "simple solid." Of the two more

abundant neon isotopes, the lighter has a larger zero-point energy (important in determining thermodynamic properties) and may be expected to have

a slightly larger molecular volume than the heavier. X-ray diffraction measurements, recently completed at the Bureau, provide values for the lattice

constants of the two isotopes throughout most of the temperature range in

which they exist as solids (0 to 25 °K) , and show this is to be true. Thermal expansion coefficients have also been computed and used to calculate

the Griineisen constant, which increases slightly in this temperature range.

Crystalline Forms of Bismuth Oxide. Bismuth oxide (Bi2 03 ) is assuming an increasingly important role in the ceramics industry as a constituent of glasses of high refractive index, glazes with excellent bonding

capabilities, and ceramic bodies having special nuclear and electronic applications. Various crystalline forms of bismuth oxide are being studied, as well as their reactions with other oxides.

In this work, various forms of bismuth oxide and the effect of adding 33

selected oxides to these forms were studied by means of high-temperature

X-ray and differential thermal analysis. The first part of the studies showed

that bismuth oxide possesses two stable and two metastable forms; the con714-691 O—64 8 103
ditions for these formations were determined. In the oxide-addition portion

of the study, phase diagrams showing the relationships between temperature,

composition, and phases present were constructed. The results clarified previously conflicting findings and provided a background of fundamental new

data.

Random Network Models for Liquid and Glass Studies. Bureau

scientists are studying the molecular arrangement of silica glass and liquid

water by employing wire random network models of the type first made at

the Bureau about 1957. The concept of a "random network theory" has

been discussed qualitatively, but the only previous structural models receiving

detailed quantitative consideration have been unrealistic complex arrangements of high symmetry.

In the present study, the models are synthesized according to a set of rules

representing the conditions of a real condensation process. Normal con- densation leads to the random network, but if a single six-membered ring

of the crystalline structure is present as an initial nucleus, then the condensation process leads to the crystalline structure entirely.

For the quantitative study of the statistical topology and geometry of these

new models, high-speed computer techniques are being used. At present the

data are obtained by determining the coordinates of each unit in the actual

physical model, but better statistical data may be obtained eventually from

larger models whose synthesis is entirely mathematical.

Determining positions of structural units in a random tetrahedral network representing molecular arrangements in such important materials as silica glass

and liquid water. Understanding the structure of such materials would shed

much light on their properties. (See p. 104.)

104
Vapor-Pressure Studies. A program for defining the general problems involved in making precise vapor-pressure and heat-of-vaporization measurements, seeking solutions to these problems, and applying new techniques

to vapor-pressure measurements of the platinum metals group is being con- ducted at the Bureau with the support of the National Aeronautics and Space

Administration. A vacuum microbalance technique has been developed

and applied to heat-of-vaporization and vapor-pressure measurements of

platinum, iridium, rhodium, palladium, ruthenium, and osmium at temperatures near 2500 °K. Measurements of the latter two elements have been

completed during the year.

Improved measurement techniques have successively increased the precision and accuracy of the data obtained in the studies. As a result, sources

of measurement error originally masked by the scatter of the data and thought

to be insignificant are now detectable.

Attempts to measure vapor pressures of the platinum metals in the range

of 10"12 atmospheres (atm) resulted in an abnormally low vaporization rate, as the substance evaporated into a vacuum of about 10~9 atm. Impurities such

as oxygen or carbon may form a stable layer on the surface of these substances, thus inhibiting the vaporization process, but a much more thorough

investigation must be undertaken before definite conclusions can be drawn.

Crystal Structure Determinations. In studying the structure of matter by X-ray diffraction, several compounds have shown interesting and un- usual characteristics. For example, the structural determinations of barium

tetraborate (BaB4 07 ) revealed an unusual, previously unknown, boron-oxygen

network consisting of well-known subunits of linked six-membered boronoxygen rings. Half of the boron is tetrahedrally coordinated and half is triangularly coordinated. The barium-oxygen and barium-barium distances

correlated very well with the cation distribution in glasses as determined by

X-ray radial distribution studies.

The structures of sodium trimetaphosphate (Na3 P3 09 ) and sodium trimetaphosphate monohydrate (Na3 P3 09

• H2 0) are unusual in that the hydrate has

the same basic structure as the anhydrous salt, although the material is not zeolitic. Other structural investigations were recently completed on

1-ethyldecaborane, lithium dipotassium trimetaphosphate monohydrate

(LiK^PsOg-HzO), and sodium tetrahydroxyborate dihydrate (NaB(OH) 4

- 2H2 0), whose structure was determined by a direct method which tested

new phase determination equations.

Phase Change Studies of Silica-Metal Oxide Systems. Phase

changes in silica-metal oxide systems result in varying degrees of opalescence.

Such changes, noted in immiscible liquid studies, may have application in

improved turbidity standards.

In the immiscibility studies, lowering the temperature of a homogeneous

mixture of liquids to a particular critical temperature caused a new liquid

phase to appear as droplets at many points throughout the liquid. These

droplets subsequently coalesced into larger droplets and finally formed a

separate immiscible layer. If a homogeneous liquid mixture is cooled below

105
its particular critical temperature, the new liquid phase occurs spontaneously;

yet the high viscosity of the homogeneous mixture at this temperature inhibits coalescence, allowing the early stages of phase separation to be observed.

Phase change studies at the Bureau, conducted in silica-metal oxide sys- tems, show that, aside from droplet-shaped phases, a continuous fibrous

network is formed. This fact suggests the presence of a nucleating polymer

network in the homogenous melt before phase separation occurs. A study

of these nucleating phenomena, and of the subsequent coalescence process,

shows that glasses having a controllable degree of light scattering can be

produced. Glasses of this type are being evaluated as turbidity standards

to replace less durable plastic and liquid standards presently in use. Standard Glasses for Viscosity Measurements. Standard glass No.

710 (soda-lime-silica) has been issued as a standard for calibrating commercial glass viscometers. Another glass No. 711 (lead-silica) is now being processed and will soon be ready for domestic and foreign distribution as a second viscosity standard. Laboratories carrying on extensive research

programs, and laboratories committed to routine physical properties measurements, have created a strong demand for standard glasses of this type.

A second series of glasses, two- or three-component glasses of high purity,

will be made for use in studies concerning the constitution of glasses.

Through systematic studies on properties of simple glasses from a common

source, information can be gathered and correlated to give positive results

and interpretations concerning the structure of glass.

Elastic Constant Data. The Bureau conducts a program of refining

and improving methods of determining elastic constants of various materials.

In determining such values for rutile (Ti02 ), three of a set of six values

disagreed with values reported elsewhere. Subsequent checking showed

that if the values used in the previous work were corrected for their crystallographic orientations, good agreement could be obtained. The values for

rutile are now regarded as well established.

Velocity of sound measurements should be made along symmetry axes

in cubic crystals because the resulting equations for computing elastic constants are then much simpler. The Bureau has put the equations into a form suitable for use along any axis. These equations have been tested

by redetermining values of the elastic constant of strontium titanate, and

good agreement was obtained with previous values. This method has been

used to determine the elastic constants of uranium dioxide.

Structural Studies of Materials Under High Pressures. Many ele- ments and compounds may be changed from one crystalline form to another

by varying the temperature or pressure or both. This phenomenon, generally known as polymorphism, is more specifically known as allotropism

for the elements. Phase transformations occur more often with pressure

variation than with temperature variation. Until the crystal structure of

these polymorphs is determined, data on the physical properties of the highpressure phases are of limited value.

106
Left: X-ray diffraction camera which incorporates an opposed diamond-anvil

pressure cell. Right: Matched X-ray powder diffraction patterns of potassium

iodide showing high- and low-pressure forms. Left half represents the normal

face-centered cubic structure at 1 bar. Right half, at 20 kilobars, shows a simple cubic structure. The pattern of the salt is shown by the rings and

arcs. The spots are due to diffraction from the diamonds. (See p. 106.)

The Bureau has developed an X-ray powder diffraction camera for obtaining structural information on materials subjected to pressures as high

as 70 kilobars. This technique is useful for showing that a real trans- formation exists, particularly in those cases where other techniques, such

as electrical resistance and density measurements, either give ambiguous

results or erroneously indicate the absence of real transitions.

In applying this high-pressure device to studies of the alkali halides,

potassium and rubidium halides and also cesium fluoride, were all shown

to have a sodium chloride-type structure at 1 atm and 25 °C, and convert

to a cesium chloride-type structure at elevated pressures.

Other studies on some rare-earth metals have shown that allotropy exists

in lanthanum, cerium, praseodymium, and neodymium at elevated pressures. The structure-types of these rare-earth allotropes are being determined.

107
Mechanical Properties of Ceramic Bodies. Many mechanical properties of brittle polycrystalline bodies axe extremely structure-sensitive.

Knowledge of this structure sensitivity is essential to intelligent measure- ment and control of the mechanical properties of such materials. To help

meet this need, the Bureau, partially supported by the Atomic Energy

Commission, conducts studies of the influence of microstructure on the

strength and elasticity of brittle polycrystalline bodies—in particular, ceramic

bodies.

The strength of such bodies strongly depends on their grain size and

the minimal degree of continuity within them, the latter being thought of

in terms of porosity. Only the very general trend of this dependence was

previously known, namely that their strength decreases with an increase in

either porosity or grain size. In the present study, a more definitive approximation of this dependence was formulated. For example, the studies showed that the strength

of porous brittle polycrystalline bodies decreases approximately logarithmically with both increasing porosity and a logarithmic increase in

grain size. This approximation is applicable for ceramic bodies of alumina,

beryllia, magnesia, thoria, urania, and chromium carbide. The approximation, expressed in equation form, is gaining some acceptance in the

field of ceramics as a useful empicism.

Other efforts in the present study have been toward developing a micrographic measure of the minimal degree of continuity within ceramic bodies.

Such a measure has been developed and is being utilized at present to derive a truer and less empirical representation of the structure sensitivity

of the strength of brittle polycrystalline bodies.

2.2.4. METALLURGY

Metallurgical research is directed primarily toward increasing our understanding of the properties of metals in order to encourage the optimum use

of existing metals and alloys and to stimulate the development of new ones having desirable properties. Broad programs of fundamental and applied research are conducted which attempt to relate the macroscopic properties of metals and alloys to their known structure. Crystal structure and the role of dislocations and point defects are of primary importance,

although in some cases more gross structural features such as grain size,

shape, and distribution are investigated. The electronic structure of metals

and alloys is investigated to obtain basic knowledge on the cohesion of

metals. Important phenomena in metallurgy such as diffusion, crystal

growth, fatigue, plastic deformation, and corrosion are studied intensively,

and explanations in terms of atomic mechanisms are developed.

The metallurgy laboratories also provide advisory services to other Government agencies, particularly in connection with the investigation of serv- ice failures of transportation equipment. Participation in the Bureau's

standard samples program by the development of specific standards of

gases in metals is another activity.

108
Metal Fatigue Investigated in Aluminum Alloys. In a recently

completed investigation of the effect of environment on the fatigue strength

of aluminum alloys, tests were conducted in which the humidity was changed

during the test. Although a high-humidity atmosphere is detrimental to fatigue strength, the results of this investigation showed that the environment during the initial part of the test has no effect on the total number of

cycles to fracture. As stressing is continued beyond this initial period,

fatigue cracks develop rapidly if moisture is present and slowly if the

atmosphere is dry.

Many of the fracture surfaces of the specimens tested in this investigation showed small areas of brilliant color. Optical and electron microscope examination disclosed that the colored areas had marked striations,

due to the progress of the crack front with each cycle of loading. Where

the striation spacing was about equal to the wavelength of visible light,

the surface served as a diffraction grating to produce the observed colors.

Properties of Metals at Elevated Temperatures. Creep tests, made

below 1200 °F on cold-drawn and aged specimens of a nickel-aluminum

alloy, showed that the creep properties of the metal were improved by prior

cold-drawing. Additional improvements were obtained by aging the specimens prior to testing in creep. Conformance to current theories of deformation was obtained only over limited ranges of temperatures and stresses,

Observing colored areas on a metal fatigue fracture surface, NBS scientists

took electron micrographs to determine the microscopic structures responsible

for the color effect. They found that striations are caused by the intermittent

progress of the crack front with each cycle of load ; where the spacing is suffi- ciently regular, the surface behaves like a diffraction grating to produce the

color phenomena. (6,000 X) (See p.109.)

109
due in part to microstructural changes and to precipitation occurring during

the tests. Light and electron microscopy showed that the size of the slip

bands, precipitates, and subgrains increased with increase in test temperature and with decrease in stress. Some data were obtained in a study to determine the influence of elevated

temperatures (up to 1200 °F) and stress systems on the tensile properties

of a titanium—8 aluminum—1 molybdenum—1 vanadium alloy. Initial results indicate that the flow and fracture strengths increase with increase in

notch depth and with decrease in notch angle or root radius. Additional

research is being conducted to correlate the relations of atomistic structure of metals to engineering properties of these metals.

Gage Block Materials Demonstrate Desired Stability. Two types

of gage blocks developed during the past few years indicated a dimensional

stability of better than 0.1 microinch per inch per year. Seven additional

types, all having a surface hardness of Rc 65 or greater, were produced

which exhibit stability of betwen 0.1 and 0.2 microinch per inch per year.

This degree of stability meets the target requirements of the project. Research is continuing to further improve other properties (thermal, corrosion,

wear) and to establish performance characteristics over longer periods of

time. Studies to determine the nature and kinetics of some of the less understood processes causing instability are being continued.

Deformation of Metals Studied at Low Temperatures. The effect

of multiaxial stresses induced by notches on the tensile deformation and

fracture characteristics of metals is being investigated at low temperatures.

In current work, annealed specimens of type 310 austenitic stainless steel,

a ductile metal of face-centered cubic structure, are being used. Tensile

specimens are of circular cross section and have circumferential notches of

selected geometries and depths.

Data obtained in tests at room temperature on deeply notched specimens

showed that a crack initiated in the region at the root of the notch at a relatively low strain grows slowly with additional deformation of the specimen.

For example, a visible crack was initiated in a specimen at a reduction in

area value of approximately 20 percent at the notched section, even though

the reduction in area at the maximum load condition was nearly 30 percent and the reduction of area at complete fracture was 55 percent.

Further studies are in progress to determine the specific effect of the

geometry of the notch on the deformation and fracture characteristics of

this steel. Slack-Quenching Technique Developed. The best combination of

high strength and ductility of structural steels is usually obtained by complete hardening and tempering. Although it is known that incomplete hardening (slack quenching) with or without tempering results in an inferior

combination of strength and ductility, quantitative evaluations of its del- eterious effect have not been possible because of lack of means for producing specimens with controlled amounts of slack-quenched structures.

110
Suitable techniques were developed during the past year, and the effect of

slack quenching upon the tensile and fatigue properties of steels is being

studied.

Stress Corrosion of Carbon Steels. In experiments with notched

specimens of four different low-carbon steels, intercrystalline stress- corrosion cracks formed in pairs at the roots of notches in ammonium

nitrate solutions, with no evidence of hydrogen evolution. On the other

hand, single cracks formed in acetic acid-hydrogen sulfide solutions that were primarily transcrystalline and there was evolution of hydrogen. It

is therefore not likely that hydrogen plays any part in the stress-corrosion

cracking of low-carbon steels, and that hydrogen embrittlement is an

entirely different type of phenomenon.

Effect of Applied Current on Aluminum Corrosion. Studies of

the effect of current on the corrosion of aluminum showed that continuously applied cathodic currents provide cathodic protection of the metal

in neutral and acid sodium chloride solutions, but that cathodic corrosion

occurs in alkaline salt solutions.

Corrosion Reactions Studied at Metal Surfaces. Experiments on

the initial stages of the oxidation of iron at room temperature indicated

that the rate of oxidation depended on the pressure below about 10"4 torr,

but that it was pressure independent above that pressure. The increase in

thickness at the lower pressures varied linearly with time at the beginning

of the process, as predicted by the Cabrera theory.

The nature of the films formed on anodically polarized iron surfaces was also investigated. It was found that the passive films formed in both

acidic and slightly alkaline solutions were three-dimensional compound

films rather than oxygen monolayers as stated in some theories.

Studies of the initiation of metal oxidation with the field emission microscope, partially supported by the Advanced Research Projects Agency, were continued during the year. At low oxygen pressures, the formation of nickel oxide showed a strong dependence upon the metal crystal

face.

Pure Alloys Prepared. Some projects under way at the Bureau re- quire special alloys of high purity or with other special properties. Since

they are not available commercially, a laboratory was set up for the preparation of such materials. Typical examples of those prepared during the

year were high-purity magnetic and nonmagnetic alloys less than 325-

sieve size for nuclear magnetic resonance studies. Several series of highpurity alloys were made for corrosion studies and special ternary alloys

of molybdenum, chromium, and nickel for other types of research.

Standard Samples. The gas-content analyses of samples of unalloyed

titanium and of an 8 percent manganese-titanium alloy were received

from cooperating laboratories and the analyses are being evaluated prior

to the issuance of the materials as standard samples. The gas content

of three other titanium alloys and of four steels is also being determined,

so that they may be made available as standard samples.

Ill
Equilibrium Diagrams Developed. NBS metallurgists, in work for

the Atomic Energy Commission, studied the metallic reactions between

uranium and the individual elements of the platinum metals by measuring

the properties of the respective alloys. The resultant data, presented in

the form of equilibrium diagrams, show the compounds formed between

two elements, the temperatures at which the metallic reactions occur, the

mutual solid solubilities, and the transformation temperatures of uranium.

The diagrams form the basis for further theoretical work on the interactions of the individual metallic elements.

Experimental Alloy Demonstrates Usefulness. The superiority of

the 60 chromium-40 nickel binary alloy over conventional iron-base alloys,

when subjected to corrosion-erosion attack in oil-fired naval boilers, was

exhibited both in laboratory tests and in actual usage on naval vessels. Further tests showed that the resistance of the alloy can be improved by

the addition of certain elements, and by preparation under vacuum conditions rather than by melting under an argon atmosphere. This work

was supported by the Navy Bureau of Ships.

Steel Pilings Inspected. Under the sponsorship of the American Iron

and Steel Institute, driven steel pilings which had been in service for from

7 to 40 years in a variety of soil conditions in the country were inspected

during the year. No appreciable corrosion was found in "undisturbed"

soils below the water table regardless of the type of soil into which the

pilings were driven. Above the water table some, but not serious, cor- rosion was found. These results contradict those often obtained on pipes

and other materials buried in "disturbed" soils, and the reason for these

different findings is being sought.

Correlation Effects for Impurity Diffusion. Since an impurity

atom in a metal can strongly affect the vacancy jump frequencies in its

vicinity, correlations between the directions of successive atom jumps are

especially important to studies of impurity diffusion. In recent research,

detailed calculations were made to determine the effect that dissociation

and re-association of vacancy-impurity complexes has on these correlations,

and a nonzero lower limit was established. The resulting equations allow

a more detailed description of vacancy jump frequencies near an impurity.

Electron Microanalysis Provides Basic Data. The Bureau's elec- tron probe microanalyzer, which permits quantitative chemical analyses in

situ to be made at a 1-micron level of spatial resolution, was used to investigate the uniformity of elements in low-alloy standard steels. An NBS steel,

designated Standard Sample No. 461, was found to be uniform on a microscale in both iron and nickel. A decomposition mechanism for columnar

grains formed by nitriding a titanium alloy was also deduced with the aid

of the microanalyzer. Theoretical work was directed at the methods used for

reducing directly obtained X-ray intensities to chemical compositions.

Quantitative Metallography Derived With Computer. A dataprocessing program for the automatic quantitative analysis on micrographs

of an NBS electronic computer was completed and applied to a number of

112
research problems. In this program, 28 picture control and analysis operations are achieved by simple orders in English format. During the year,

analyses were completed on a series of color micrographs of niobium-tin

superconductor wire and on the microstructure of a steel designated Standard Sample No. 461. Work was undertaken to develop a standard for

graphite particle size in ferrous materials by means of the computer technique.

Feasibility tests were conducted on micrographs of photographic emulsions

and on biological micrographs in the fields of chromosome identification, cancer cells, and nerve cells. The program was found generally applicable

to these types of micrographic problems as well as those in metallurgy.

Programming is in progress for a more extensive and faster system on a new

NBS computer.

Anisotropic Effects Studied in a Cubic Alloy. An investigation of

the Pb207 nuclear magnetic resonance absorption linewidth in a series of

lead-indium alloys as a function of applied magnetic field revealed a broadening mechanism heretofore unobserved in alloys. This source of line broadening arises because of the interaction between nuclear spins and unpaired

electron spins outside the nucleus. It vanishes when the resonant nuclei

have local cubic symmetry. The presence of this field-dependent "anisotropic Knight shift" broadening is possible in the face-centered cubic phase

of the alloy because of the deviation from local cubic symmetry at the

Pb207 sites produced by adding indium atoms, and the broadening indicates a large anisotropy in the electronic wave functions at the Fermi level in this

alloy.

X-Ray Diffraction Employed for Crystal Structure Studies. This

work is concerned with the analysis of lattice stresses as deduced from interatomic layer strains, measured from X-ray diffraction data. Some results

concerning residual stresses in plastically deformed steels were published,

and a study is now in progress on coarse-grained polycrystalline samples.

Also under way is an investigation of crystal perfection by means of fine-focus

divergent beam X-ray techniques.

Dislocations in Metals Investigated. The effects due to dislocations

in metals are currently being examined from several points of view. Transmission electron microscope methods are being employed to examine stacking faults and twins in high-purity copper. Thermal evaporation from

cleavage surfaces of zinc single crystals was found to occur preferentially

at dislocations. The detailed shapes of the resulting evaporation pits were

studied as a function of vapor undersaturation and surface impurities.

Step configurations on the zinc surfaces were examined by electron microscope replica techniques. The vapor deposition of gold on these surfaces

is also being employed to study the surface steps that are related to dis- locations in the crystals.

Kinetics of Whisker Growth and Evaporation. In Bureau studies

of the kinetics of metal whisker growth from the vapor phase, it is assumed

that growth takes place by adsorbed atoms surface-diffusing to a sink (an

emergent screw dislocation) at the whisker tip. But the problems of de113
Optical interference micrograph of a thermal evaporation pit on a zinc surface.

These pits are being studied for information on the effect of dislocations on

metal behavior. (460X) (Seep. 113.)

scribing growth rate as a function of pressure, the evaporation time of

adsorbed atoms, and the surface-diffusion coefficient are complicated by

the occurrence of moving boundary conditions. Hence, an integral equation which incorporates these conditions was derived and programmed for

the Bureau's electronic computer. The resulting numerical solutions should

be useful in analyzing the experimental data thus far obtained on whisker

growth.

In work partially sponsored by the Advanced Research Projects Agency,

data on the growth and evaporation kinetics of crystal whiskers of potassium and of mercury were obtained from direct optical measurements in

sealed-off vessels prepared by ultra-high-vacuum techniques. The data were compared with theoretical estimates obtained from solutions of the surfacediffusion equation. Over certain ranges of vapor undersaturation, crystal

edges were not found in this work to act as evaporation step sources; the

subsequent growth and evaporation of whiskers appeared to be quite symmetrical processes that could be well described by a single surface-diffusion

equation.

Properties of Electrodeposited Copper. Electrodeposited copper

is an important material for electroforming and for other engineering applications; however, to improve and expand its usefulness in these applications, additional information is needed on the relationships between its properties and conditions of deposition. To fill this need a new program,

114
supported jointly by the American Electroplaters' Society, the International

Copper Research Association, and the Bureau was initiated.

The microstructure of the deposits and their mechanical, electrical, and

thermal properties will be determined and related to the type of plating

bath and operating conditions. A similar study of electrodeposited nickel

completed sometime ago was found to be of considerable value to the electroplating industry.

Electrocrystallization Investigated. A program was initiated under

the sponsorship of the Advanced Research Projects Agency and the Harry

Diamond Laboratories to study the growth of metal crystals by electrodeposition. This method of growing crystals offers a distinct advantage over other

methods in the apparent ease by which the rate of growth may be controlled.

Polycrystalline masses, dendritic growth, and single crystal growth can be achieved from aqueous solutions and from fused salts. This flexible

technique of growing metal crystals promises to yield significant information of scientific interest. The initial phase demonstrated the prevalence

of growth twins in electrodeposits, and these twins appear to be related to the growth mechanism of dendrites and of dense deposits.

Distributions of crystal orientation in polycrystal electrodeposits of copper were determined for the first time and change in distribution accompanying

deposit growth was found. Growth of copper dendrites showed a fivefold

symmetry about the axis of growth.

Calorimetry Used To Study Fused Salts. A calorimeter, operated at temperatures up to about 800 °C, was constructed for measuring the heat

effects involved in the formation of complex ions in fused salts. The formula of a complex formed from two salts can be determined by measuring

the heat effects attending the addition of small increments of one salt to mixtures of the salts covering the whole range of composition. The heat

effect varies with the composition of the melt. In current work, sponsored

by the Atomic Energy Commission, the complex ions formed in a mixture

of molten potassium chloride and cadmium chloride are being studied.

Peltier Effect Measured at Liquid Junctions. The flow of current

across the junction of two electrolytes—for example, 1.0 molal hydrochloric

acid in contact with 3.0 molal potassium chloride—results in either a heating

or cooling effect at the junction, depending on the direction of current flow.

This phenomenom, which is called the Peltier effect, is considered due to the

existence of a voltage at the junction, and it is measured with sensitive

thermistors. The value of the Peltier voltage is obtained by dividing the

heat effect in joules by the current in coulombs. In a recent study, sponsored

by the Atomic Energy Commission, the Peltier voltage was found to be about

80 mv for the two solutions mentioned and to be independent of the current

density, the diffuseness of the junction, or the length of time that current was passed across the junction.

Cooperative Services Provided. Among the more interesting co- operative services of the engineering metallurgy laboratory performed during

the year were the examination of stainless steel reflecting disks and support

115
arms for the Post Office Department (these disks are designed for attachment to Post Office trucks so that drivers may view the area immediately

below the bumpers and so avoid striking small children) ; the examination,

for the Interstate Commerce Commission, of the welds from a mobile propane gas tank that exploded with considerable loss of life and property in

Berlin, N.Y. : and the collaboration with Bureau staff in the Engineering

Mechanics Laboratory on the selection of stainless steel for large dead-weight

testing machines.

2.2.5. POLYMERS

The Bureau conducts research on natural and synthetic polymeric materials—rubber, textiles, paper, leather, and plastics—which are composed

of long, chainlike molecules. Many of the useful properties of these materials depend upon molecular size, shape, distribution, and flexibility. To

aid in the efficient utilization of polymeric materials, the Bureau investigates

the mechanisms involved in forming polymers, their constitution and molecular structure, and methods for measuring their properties. The data

obtained are of value not only in developing new materials having specific

properties, but also in devising standard techniques for evaluating those

already in use and in preparing engineering standards to promote the eco- nomic growth of polymer industries.

Methods were reported during the year for the analysis of ethylenepropylene rubber, determination of bitumen content of expansion-joint fillers,

measurement of tensile properties of paper and tongue-tearing strength

of woven fabrics, identification of antioxidants in synthetic rubber, and

nondestructive examination of internal structure of composite products by

point-projection X-ray microscopy. Work was undertaken on the macroporous structure of leather, phase transformations in polymers at high pressures, phase equilibria in polymer solutions, thermodynamic properties of

polymers, effect of pressure on the crystallization of natural rubber, and

failure behavior of fibers at high impact velocities. Chemical investigations were concerned with radiation-induced polymerization at high pressures, synthesis of fluoroaromatic monomers and polymers, effects of gammaradiation on polymer scission and crosslinking, structure of metallo-organic

coordination polymers, production of two stereoregular forms of polyacenaphthylene, and adsorption of polystyrene from solution onto a metal

substrate. Two standard samples of polystyrene were issued for calibration

of molecular weight measurements. In research conducted in cooperation

with the American Dental Association and Federal dental services, significant contributions were made to knowledge of the structure and strength

of teeth, the analysis of gold alloys, and the improvement of dental cementing compounds.

Ethylene-Propylene Copolymers Analyzed. Elastomers prepared

by random copolymerization of ethylene and propylene with Ziegler-Natta

type catalysts are commercially important because of the low cost of the raw materials and the wide range of physical properties obtainable. To

achieve the elastic quality of rubber, the propylene content of the polymer

116
must be controlled within certain limits. An analytical method developed

for quantitatively determining propylene in both raw and cured copolymers

is applicable over the entire range of propylene concentrations. The method

is based on the fact that pyrolysis of ethylene-propylene copolymers produces characteristic unsaturated carbon compounds which are identified by

infrared absorption spectroscopy. It was found that the ratio of the

absorption of the vinyl groups to that of the vinylidene groups in the pyrolyzate varies reproducibly with the mole fraction of propylene in ethylenepropylene copolymers.

Bitumen Content in Expansion Joint Fillers Readily Determined.

A comparison of a Soxhlet extraction method for the determination of bi- tumen content in expansion-joint fillers (made of bitumen and cellulose

fiber, cork, or glass wool ) with the current centrifuge method recommended

by the American Society for Testing and Materials, showed that the Soxhlet

procedure required less operator time and smaller amounts of solvent than

did the ASTM method. With the Soxhlet procedure it was also possible

to analyze a large number of samples concurrently with a minimum amount

of attention. A statistical analysis of the data showed that the results obtained by both methods were in good agreement.

Tensile Properties of Paper. Tensile properties have long been used

as a measure of the quality of certain papers, but in recent years they have

assumed added significance in the efforts of manufacturers to develop stronger

papers for shipping sacks and similar products. An interlaboratory study

of the precision of test methods for tensile strength, stretch, and tensile

energy absorption was therefore undertaken at the request of the Technical

Association of the Pulp and Paper Industry to improve the precision of the

measurement system. Twenty laboratories participated in the testing of 22

materials.

The results showed that a standard reference material would be of little or no value for standardizing the tests for tensile breaking strength and

tensile energy absorption, although it might improve the precision of the

stretch method used. The 95 percent probability limits for the differences

between the averages for two sets of 12 measurements by each method were

found for tests of the same material by a single observer, for tests of different

materials measured under the same conditions, and for results obtained by

different observers or instruments.

Tongue-Tear Methods for Woven Fabrics Evaluated. The tonguetear (or "single-rip") method is widely used in measuring the strength of woven fabrics, but five different procedures have been standardized and

published for this test. The Textiles Committee of the American Society

for Testing and Materials therefore requested the Bureau to undertake a study of their relative precision. Thirty laboratories collaborated in the

project, which was conducted by the Mandel-Lashof statistical plan with

eight different materials.

The results showed that two of the procedures in which a constant-rate- of-elongation testing machine is used are better than the other three. In

117
one of the superior procedures, the result from an integrator average is computed and, in the other, an average of five peaks in the autographic

record of the tearing load is used. The results also showed that five replicate determinations are needed for routine measurements and ten for interlaboratory measurements, and that a standard reference material would be of

little value in improving the precision of measurement. Estimates were made

of the precision of the five procedures for use in ASTM precision statements. Color Tests Devised for Antioxidants in Synthetic Rubbers. A

scheme of color tests was developed for identifying the five antioxidants com- monly used in styrene-butadiene synthetic rubbers. These antioxidants in- clude naphthylamine and diphenylamine compounds, styrenated phenols, and

alkylated arylphosphites. By the use of specified successive tests involving

two or more of a group of twelve reagents, the uncertainty of distinguishing

between similar colors obtained with a single test is overcome. The procedure also permits the detection of small amounts of staining antioxidants,

which might be present as contaminants.

Point-Projection X-Ray Microscopy Used To Study Polymers.

Microradiography, a technique using soft X-rays generated by pointprojection sources, is being applied to the examination of a wide range

of polymeric materials. Because of its high resolution (greater than most

light microscopes) and its ability to image opaque and thick specimens,

this technique provides a powerful tool for polymer research. Studies were made on foams of polystyrene, polyurethane, vinyl, and other materials, to characterize cell structure and to correlate structural anisotropy

with physical properties.

Point-projection microradiography is being applied to the study of polymers.

This high-resolution technique can be used on opaque and thick specimens.

Left: microradiograph of chemically modified polyurethane foam; right:

fully expanded polystyrene beads. ( See p. 1 1 8.

)

118
In studies of paper formation, the method permitted detailed study of

the size and location of fillers and additives. In addition, the condition

and form of adhesives and reinforcing components in polymeric materials

could be easily imaged by the method. The point-projection source also

provides an efficient means of producing divergent-beam (Kossel) diffraction, which permits detailed analysis of the structure of crystalline monomers

and of the changes occurring during solid-state polymerization.

Leather Macroporous Structure Investigated. The pore structures

in leather and other natural collagenous materials, and in plastics and

fritted glass disks were compared with a mercury porosimeter at absolute

pressures ranging from 5 to 3000 psi. Pore radii corresponding to these

pressures are in the macropore range from 50 to 0.04 microns (fi). The

results demonstrated that many different pore sizes exist in the fibrous

structure of leather, whereas the pores in manufactured materials are more uniform in size. A differential analysis of integral volume-pressure curves derived for

collagenous materials in the form of hides indicated that a large part of

the pore volume occurs at radii of from 5 to 0.5 p. In rattail tendons, a large

fraction is in the 2.5- to 0.5-ju radius range. The volume from pores

smaller than 0.25-/U, radius is probably within the fibril region of the

collagenous materials.

Structural Transformations Observed in Polymers at High Pressures. Physical changes under high pressure were observed in a variety

of polymers compressed between diamond anvils at room temperature. The

diamonds serve both as load-bearing surfaces for pressures up to 70 kilobars and as light transmitting media. The anvil device is placed on the

stage of a polarizing microscope to increase resolution. In the study, the optical appearance of some polymers (e.g., Teflon, Kel-F,

and nylon 6) changed abruptly during compression. The original field,

which showed little structure with shifting interference colors associated

with increasing photoelastic strain, was changed to a reticulated structure with low birefringence. The transition point was usually marked by a snapping noise. Other polymers (natural rubber, polyisobutylene, and

ethylene-propylene rubber) showed a more gradual transformation in which

internal grooves developed and spread throughout the field with increased

pressure until a reticulated structure resulted.

The transformations were irreversible, at least on a time scale of several

months. X-ray diffraction patterns of compressed rubbers after removal

from the anvil device showed crystalline rings which were not previously

present. Polyethylene displayed a new spacing associated with a psuedotriclinic unit cell. Polymers that transformed abruptly had a polymer glass

transition temperature (T0 ) above room temperature; those that trans- formed gradually had a Tg below room temperature.

Phase Equilibria in Polymer Solutions. Light-scattering studies of

polystyrene-cyclohexane solutions near their maximum phase separation temperature showed differences in the distribution of molecular weights that

714-691 0—64 9 119
could not be easily determined by other physical chemical methods. The

light scattered in the direction of the incoming beam was determined by

measurement of the light scattered to the side and extrapolation to the forward direction. At a given temperature the scattering was measured as a function of concentration over a concentration range of from 1 to 10 percent.

The temperatures varied from a few hundredths to a few tenths of a degree

from the critical temperature.

The shape of the resulting isotherms and the shift of the maximum indicated the polydispersity of the sample. The measurements obtained constitute a sensitive test for the existence of true monodispersity in a polymer.

They also lead to a direct experimental determination of the thermodynamic

properties of concentrated polymer solutions. The results show that current

theory of phase equilibria in polymer systems does not satisfactorily fit experimental data, since it does not include concentration-dependent interaction

terms in the critical region.

Statistical Calculations Made of Polymer Properties. Thermodynamic properties of polymer chains were calculated on a statistical basis

in a recent Bureau study. Nonbonded nearest-neighbor, next-to-nearest- neighbor, and other interactions were counted, and, by introducing an

appropriate potential energy of interaction between the neighbors, various

thermodynamic properties could be derived. Attractive forces between

neighbors led to very compact (supercoiled) conformations resembling

tightly packed spheres. However, repulsive forces extending over a reason- ably large range of intramolecular separations led to rodlike polymer

conformations.

Computations were made of the free energy and of the entropy per link of

polymer, with respect to a preselected reference state. This state corresponds

to a conformationally unrestricted polymer coil. Variations in the thermodynamic properties of a polymer as it undergoes conformational changes

could thus be derived. From such calculations it was concluded that the

thermodynamic properties of polymers do not vary markedly with molecular

dimensions. Even in a very good solvent, in which polymer-solvent contacts are favored over polymer-polymer contacts, polymer chains tend to remain

in relatively coiled conformations. 6 Rubber Crystallization Investigated. The crystallization of purified

natural rubber was investigated by observing the change in volume at temperatures from +10 to —30 °C under hydrostatic pressures up to 800

kg/cm2

. Superimposable Avrami type isotherms were found at all temperatures and pressures. A study was made of the effects of temperature and

pressure on the critical free energy necessary to form a nucleus and on the

activation free energy required for transport across a liquid-nucleus interface. It was found that the data could be quantitatively explained by means

of a simple assumption that the activation free energy for transport was

independent of the temperature.

Failure Phenomena of Fibers Studied at High Impact Velocities.

When a filament is struck transversely, a V-shaped wave of transverse motion

120
2 3 ,i 5 6 7 8 9 '< H 1 2 3 4

Multiple microflash photograph of a textile yarn being broken by a rifle bullet. This method is used to study the behavior of textiles under high impact forces.

(See p. 120.)

spreads outward at a velocity that depends upon the velocity of impact.

Data on the wave velocities, corresponding to impact velocities between

10 and 700 meters per second (m/sec), can be analyzed to determine stressstrain behavior at straining rates of the order of 100,000 m/sec. In recent experiments, textile yarns were impacted with rifle bullets and a multiple

exposure of the resulting configurations was obtained by means of microflash photography. The flash apparatus emitted a series of 15 flashes of

1 -microsecond (/xsec) duration separated by time intervals as short as 10

usee.

121
It was found that the time required to hreak a yarn depended upon the

impact velocity. For example, a high-tenacity polyethylene terephthalate

yarn broke 10 /xsec after impact at 620 m/sec, but required 100 psee to break after an impact at a velocity of 420 m/sec. Similar relationships

existed between impact velocity and the breaking tenacities and elongations of the specimens. Information of this type is sought since it gives a better understanding of the mechanical properties of polymers and their

dependence upon molecular structure. Radiation-Induced Polymerization Under High Pressure. To determine the influence of pressure on polymerization and to produce poly- mers of unusual or novel structure, studies are under way in which monomers

that are nonpolymerizable under ordinary conditions are subjected to pres- sures near 20,000 atm and irradiated at 25 to 300 °C with gamma-rays.

Placing a monomer sample into a cobalt 60 radiation source 10 feet under

water (loicer center). Under the influence of the gamma radiation, high

pressures, and high temperatures, several monomers which do not ordinarily

form polymers have been polymerized. Polymers of unusual or novel struc- ture with unique properties may be produced by such studies. (See p. 122.)

122
Monomers thus far polymerized in this investigation, sponsored by the U.S.

Army Research Office, included perfluoroheptene, carbon disulfide, 4-chloroperfluoroheptadiene-l,6,perfluoropentadiene-l,4, and perfluorocyclobutene.

The results showed thai; the rate of polymerization is usually proportional

to the square root of the irradiation intensity. In several instances, poly- mers of promising physical properties and molecular weights were obtained.

Equipment is being developed to conduct the polymerization at still greater

pressures.

Fluoroaromatic Polymers Prepared. An intensive study of the

chemical synthesis of new perfluoroaromatic monomers is being carried out

under the sponsorship of the Bureau of Naval Weapons, with the objective

of producing elastomers resistant to high temperatures. In this research,

perfluorophenylene ethers were prepared from pentafluorophenol and its

salts. The highest molecular weight polymer obtained exhibited interesting

properties up to approximately 400 °C, the decomposition temperature of

the material.

Perfluorovinylphenyl ether was also prepared and polymerized to low

molecular weight polymers.

It is anticipated that perfluorophenylene methylene polvmers would have

outstanding thermal stability. As a precursor to the synthesis of this polymer, p-hydro-perfluorotoluene was prepared, and its ability to undergo

anionic and cationic reactions was studied in a search for an efficient polymerization process.

High-Energy Radiation Effects on Polymers. A study of the

changes induced in the physical properties of polymers by a high-energy

radiation environment was undertaken for the National Aeronautics and

Space Administration. Such information is needed to advance both space

and nuclear technology. The results showed that the properties of an

elastomer change drastically when it is irradiated. The radiation induces

a series of complex chemical changes which lead to broken polymer chains

and to crosslinking, with both processes usually occurring simultaneously.

In the investigation, stress relaxation resulting from the rupture of polymer

chains was recorded for fluoroelastomers in a gamma-ray source. It was

found that the dose required for 50 percent stress relaxation in a copolymer

of vinylidene fluoride and hexafluoropropylene was 12 megarads (Mrad) in

the absence of air and 6 Mrad in air, at a dose rate of 0-3 Mrad/hr. Similar

findings were made on other fluoroelastomers. A rather large component

of rupture was observed in the overall crosslinking of these polymers upon

irradiation.

The rates of volatilization of polymers were recorded automatically while

they were heated in a gamma-radiation field. A greatly enhanced rate of

volatilization of polytetrafluoroethylene occurred at temperatures from 300

to 400 °C, far below the 500 °C temperature at which ordinary thermal decomposition becomes appreciable. Elucidation of the mechanism and thermodynamics of the radiation-induced degradation process is necessary before polymers suitable for use in radiation fields can be synthesized.

123
Thermal Stability of Coordination Polymers Investigated. In recent research, the thermal stability of coordination polymers of bis(8-

hydroxy-quinoline ) derivatives heated in vacuum was related to the metal

atonic thai linked the organic units (ligands) in the polymer chain. The decomposition temperatures of polymers containing either divalent manganese,

cobalt, nickel, or copper decreased linearly from approximately 510 to 420

°C with increasing atomic number of the metal. A divalent zinc polymer,

being more stable than the copper polymer, showed an interesting departure

from this trend.

It was demonstrated that the mechanism of decomposition involved

cleavage of the metal-ligand bonds at the coordination site and that the

order of stability depended on such periodic properties of the metal as

ionic potential and electronegativity. These findings may make it possible

to predict the thermal stability of other coordinated systems and they may

suggest structures for polymers of greater heat resistance.

Stereoregular Polyacenaphthylene Produced. A recent advance in

polymer chemistry is the ability to synthesize stereoregular polymers by

the use of special catalysts. Another approach to the preparation of these

regular structures is through the use of monomers of high steric hindrance.

The polymers formed from such monomers are expected to have stereo- regularity due to crowding of the bulky side groups.

Since acenaphthylene has a very large group bridging the polymerizable

vinyl group, the polymer formed from it should exhibit the extreme effects

of steric hindrance, both in its polymerization kinetics and in its physical

and chemical properties. The polymerization should occur in either a

syndiotactic "rodlike" form or an isotactic, tightly coiled helix. Meticulous

separation of the products of ionically initiated polymerization and characterization by infrared and nuclear magnetic resonance spectra show that

both structures do in fact exist in polyacenaphthylene.

Polymer Adsorption. Polystyrene films adsorbed from cyclohexane on chrome surfaces were recently studied in work partly sponsored by the

Bureau of Naval Weapons. Purpose of the study was to obtain a better

understanding of the nature of the interface between glass fiber and polymer

in reinforced plastics. In the study, ellipsometry was used to measure

changes in the state of polarization of polarized light reflected from the

film-covered surface. From these measurements, the thickness of the film was calculated to be about 200 A. The film consisted of about 12g/100 ml

of polymer and the amount adsorbed was determined to be approximately

2.25 X10-4 mg/cm2

. Molecular Weight Standards for Polystyrene. Research to improve

precision and accuracy of measurements of polymer molecular weights,

particularly by osmometry, light scattering, and ultracentrifugation, has

culminated in the issuance of two standard samples of polystyrene for calibration purposes. These materials, the first molecular weight standards for

polymers to be made available by the Bureau, will be of value to chemists

in the characterization of industrial macromoleeular produjts used in the

124
manufacture of plastics, rubbers, textiles, and paper. Molecular weight

and intrinsic viscosity are given for each sample. Each sample is also characterized for ash content, volatile content, and refractive index increment and

partial specific volume constants of the polystyrene-cyclohexane solutions

used in light scattering and sedimentation molecular weight determinations.

Structure and Strength of Teeth. Electron microscope examination

of developing enamel showed that mineralization begins by the formation

of extremely thin ribbons of calcium phosphate which subsequently thicken

to become fibrous crystals of hydroxyapatite, Ca5 (P04 ) 3 OH. In cooperation with the National Institute of Dental Research, the crystallographic and

chemical evidence concerning the nature of the ribbons was reexamined

with the conclusion that octacalcium phosphate, Ca4H(P04 )3-2.5H2 0, is a

better prototype for the ribbons than the presently accepted hydroxyapatite.

These two salts differ greatly in their chemical properties, so that a distinction as to which salt comprises the ribbons is needed for an understanding, on

the molecular level, of the calcification mechanism. For example, the pres- ence of fluoride during the enamel formative state has pronounced influence on subsequent caries development. Fluoride is known to cause octacalcium

phosphate to hydrolyze to the less soluble fluorapatite.

Dental calculus (tartar) consists of about 20 percent organic material

in a matrix of calcium salts, mainly phosphates. Studies were undertaken

to determine the composition of the organic portion for possible assistance

in the search for agents that might reduce the formation of calculus. Organic layers at the junction of the calculus deposit and tooth tissue and

throughout the deposit were demonstrated by their fluorescence. Chromatographic and electrophoretic analyses showed the presence of a mucoprotein

(a carbohydrate-protein complex), indicating a possible role of salivary

mucoid in the formation of dental calculus.

The small size of specimens that can be prepared from human teeth requires

special techiques for measuring the tensile strength of enamel and dentin.

Hence, a method was developed that employs a dumbbell type specimen of

0.0015-in.2 cross section, with notched ends embedded in resin. The resin

ends fit into grips attached to the testing machine. The dentin specimens were long enough to permit attachment of y^in. strain gages for modulus

determination. The tensile strengths of human enamel and dentin stressed

at a head speed of 0.002 in./min were 1500 and 7500 psi, respectively. The

modulus of elasticity of dentin was found to be 2.8 X 106 psi.

The studies in this program were sponsored by the American Dental Association and the Federal dental services.

X-Ray Spectrometer Used for Analysis of Dental Alloys. Standard reference samples were recently prepared for X-ray spectrometric analysis by melting the component elements—gold, platinum, palladium, silver,

copper, and zinc—of a dental alloy in a high-frequency furnace and cast- ing the alloy into disks. Compositions of the castings were subsequently

checked by chemical methods. Optimum procedures for casting the sample

and for X-ray analysis were established. Analytical curves were developed

125
relating concentrations to measured intensity of the X-ray lines Au L0, Ag

Ka,CuKa,Ft La ,Pd Ka,and ZnKa. The procedure is more rapid than wet

chemical methods and the results appear to be sufficiently accurate for general

purpose work. The American Dental Association and the Federal dental

services sponsored this study.

Dental Cements. In other work for the same sponsors, it was found

that partial substitution of o-ethoxybenzoic acid (EBA) for eugenol as a

chelating agent results in the formation of improved dental cements. A

typical cement is obtained by mixing powder containing zinc oxide, heattreated fused quartz, and hydrogenated rosin with EBA-eugenol liquid. The

resulting product has compressive, tensile, and shear strengths that are about

three times those of presently available zinc oxide-eugenol cements. Solubility and disintegration as measured by various laboratory tests are equal

to or better than those of zinc oxide-eugenol cements. The cement also shows

reduced setting contraction and water sorption.

2.3. SPECIAL TECHNICAL SERVICE

PROGRAMS

2.3.1. APPLIED MATHEMATICS

The Bureau's applied mathematics facility performs basic and applied

research and provides advisory services on the application of mathematical

and statistical techniques. Its services are available to other Government

agencies as well as to the Bureau's staff. The facility uses modern computing equipment in support of its program.

During the past year the Bureau continued research in statistical and

numerical analysis, mathematical physics, and operations research, all of

which are fundamental to its mission. Extensive assistance was rendered

in these areas and in digital computation. In the latter field, emphasis was placed on problem formulation and analysis in order to select and

develop appropriate numerical methods. Automatic high-speed computing

machines were utilized when appropriate. The mathematical program was

devoted both to problems in engineering and the physical sciences and to government problems of business management and operation, sometimes

called data processing problems. Progress was continued in exploration of

the use of modern digital computers in the mechanical translation of scientific publications, for which the need is urgent.

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 National Aeronautics and Space Administration supported

basic and applied research in numerical analysis and mathematical physics.

The study of mechanical translation of scientific publications was jointly

supported by the U.S. Army Signal Corps and the U.S. Army Research Office.

Numerical Analysis. Research in numerical analysis is of vital importance in contributing to the effective use of electronic digital computing

126
equipment, both in applying such equipment to scientific and engineering

problems and in utilizing it as an aid to decision making by management.

If an asymptotic series is truncated at (or near) its smallest term, the

resulting partial sum is often a good approximation to the wanted function

f(x), particularly for large values of x. Because of this property, these

series are frequently used in computations, even though they are really

divergent. Only a few scattered special results are known concerning the

precise magnitude of the error committed by approximating a given function

by a partial sum of its asymptotic series.

Current research is directed toward filling this gap. Considerable success has already been achieved with certain types of asymptotic series originating

from second-order ordinary differential equations; some general theorems

have been established giving precise, and realistic, error bounds which are

easily evaluated. The theorems also show, for example, why these series

provide inaccurate results near the boundaries of their regions of validity

in the complex %-plane.

Asymptotic Expansions. Work continued on the determination of error bounds for the asymptotic solution in terms of Airy functions of secondorder ordinary linear differential equations in regions containing a turn- ing point, and on the determination of complete asymptotic expansions of

such solutions.

Quadrature and Interpolation. The question of the existence and

uniqueness of functions satisfying a given set of conditions was investigated.

The use of equidistributed sequences in Monte Carlo quadrature was

investigated, both theoretically and experimentally.

Numerical experiments were conducted on the computation of highly

multiple integrals—more specifically, on the calculation of the fourth and

fifth virial coefficients of an imperfect gas—utilizing a fairly arbitrary interaction potential. Despite much activity on this problem over the past five

years, treatment of its numerical aspects remains unsatisfactory.

Linear Algebra and Matrix Theory. Bounds for the arithmetic minima

of quadratic forms were determined and the structure of classes of copositive

and positive quadratic forms was investigated. Theorems were given relative to the iterative solution of eigenvalue problems and to the iterative in- version of a matrix. Such problems are of central importance in a wide

range of investigations extending from flutter of airplane wings and critical

speeds to nuclear theory.

Machine Translation. The morphological phase of the problem of

mechanical translation of Russian into English has been entirely completed.

Theoretically, the syntactic integration phase can never be completed; but

enough progress has been made to indicate the soundness of the "predictive

analysis" scheme initiated at the Bureau. Coding for the section dealing

with the mechanical determination of the clause and phrase boundaries within

a sentence is progressing. As soon as it is completed, an open test of the

method will be made on Russian sentences composed of words formed from

the limited number of stems presently stored in the machine's glossary127
Mathematical Tables. In response to demand. Applied Mathematics

Series 27, Tables of 10'. and AMS 36, Tables of Circular and Hyperbolic

Sines and Cosines for Radian Arguments, were reissued. Underway is a

critical survey of all the Bureau tables series in view of the approaching

completion of the Handbook of Mathematical Functions.

Digital Computations. The Bureau improved its computational facilities by replacing the IBM 1401 with an IBM 1410 computer. The 1410 computer is actually rented by the Harry Diamond Laboratories, U.S. Army,

but is operated by the Bureau. In addition, the Bureau continues to operate an IBM 7090 and plans shortly to replace this with an IBM 7094. Both

scientific and data processing problems continue to require extensive use of

these computational facilities. In addition to performing computations on

its own equipment, the Bureau assists other Government agencies in setting

up problems for other computing machines. The experience gained in the performance of this service stimulated research in programming and

computational methods.

About one-third of the computing services tasks performed during the

year originated within the Bureau. The remainder were performed in assistance to such agencies as the Harry Diamond Laboratories, National

Aeronautics and Space Administration. Bureau of Public Boads. Secret

Service, Treasury Department, Veterans Administration. Peace Corps, U.S.

Military Academy, and the Office of Civil Defense. Important computations were performed on problems in the thermal dissociation of diatomic molecules, diffusion and reactions in gases, polymers, multilayer adsorption

studies, neutron cross sections, equations of state, and interaction radiation.

Among the many problems in the area of data processing where the

economic desirability of supporting the development of Mach 2 to 3 supersonic aircraft, the comparison of different tax proposals, the analysis of

check forgeries, the evaluation of applicants for the Peace Corps, the analysis

of highway and traffic problems, and a comparison of securities marketing

procedures.

Extensive research continued in the field of automatic programming and

artificial programmer-oriented computer languages. A monitoring sys- tem which previously utilized the 1401 computer as a secretary for the

7090 computer was adopted and enlarged for the 1410 computer.

Statistical Engineering. The principal function of the Bureau's statistical engineering program is to advise the Bureau's scientific and technical

personnel on the application of modern probability and statistical methods

to physical science and engineering experimentation. The aim of the program is to help the Bureau's scientists and technicians conduct their research, development, and testing programs so as to reach conclusions of

desired scope and reliability at the lowest possible cost under existing limitations of funds, equipment, materials, and personnel. Extensive services were rendered, ranging from short informal conferences to active collaboration with project leaders for periods of several months.

128
Research and Development. Two Bureau publications completed

during the past year make available to the technical public many important

results of the Bureau's research and experience in the adaptation and development of statistical methodology for application to calibration and ex- perimental programs in the physical sciences and engineering. The first of these, "Realistic Evaluation of the Precision and Accuracy of Instru- ment Calibration Systems," J. Res. NBS 67C, No. 2, 161-187 (Apr.-June

1963) is a very thorough treatment of the principles of probability and

statistics that are fundamental to the description and evaluation of the sources of errors in a measurement process. The paper derives from these

principles the appropriate techniques for assigning numerical bounds to the

uncertainties of measurement results. The second publication completed last year, Experimental Statistics (to be

issued as NBS Handbook 91), was prepared under a contract with the

former Office of Ordnance Research (now Army Research Office—Durham)

Although originally developed with the needs of the Army in mind, it should

be equally useful to other groups concerned with research and development,

both within and outside the Government. The Handbook is intended

chiefly for use by persons with an engineering background as a guide and

ready reference on the planning and interpretation of experiments and tests relating to engineering design and development programs. Model work

sheets and examples corresponding to the more common applications of statistics are provided.

The Bureau conducts a continuing program of basic research in probability and mathematical statistics to maintain and increase the effectiveness

of statistical services. During the past year, a study of a new rank sum test for outliers was completed, and an algorithm was developed for obtaining an orthogonal set of individual degrees of freedom for error. Research was continued on applications of probability theory to problems

of the reliability of complex systems. A mathematical study was made of the

reliability of a system with spare parts, where the spare parts can fail in

storage as well as in use. An investigation was initiated of mathematical

models for the description of changes through time in the probability dis- tributions of characteristics of electronic devices. The dependence of these

distributions on age and stress level was considered.

Experiment Design and Consultation. Major cooperative activities were

in connection with the Bureau's calibration programs. Methods for representing the precision and accuracy of measurement processess and statistical

designs for eliminating the effect of environmental factors are the subject of

most of the consulting activities.

A good example of this collaborative activity has been the work for the

Mass and Volume Section. In the calibration of a set of weights, different

combinations of the weights are compared in such a way that a value for

all the unknown weights is obtained. Such a schedule of weighing, called

a weighing design, has redundancy in the sense that more observations are made than there are unknowns in order that there be a check on the precision

of the measurements. New weighing designs have been created which incor129
porate a standard weight as an unknown as a check on accuracy. A program was provided for electronic computation of the results; this method greatly

simplifies the maintenance of records on the accuracy and precision of the

measurement process.

Mathematical Physics. Research in this area continued to be directed

toward the application of mathematical techniques to the solution of problems

in mathematical physics and the engineering sciences. Investigations in- cluded a combined theoretical and experimental study of the laws governing

the nonlinear deformation of viscoelastic materials: the application of the

"stroboscopic" method to the study of nonlinear ordinary differential equations arising from vibration, acoustical, and electrical circuit problems; the

determination of bounds on solutions of problems involving elliptic operators,

especially those of elasticity; research on the kinetic equations governing

various plasma flows; and a study of the feasibility of measuring the

atmospheric drag on a manned satellite by means of controls to be operated

by the astronaut. Plasma Research. Research was performed on basic problems in the

physics of ionized gases, particularly on the dynamics of motion in the pres- ence of magnetic and electric fields. This work is essential in supporting

the basic research of the Bureau and is also important to the National Aeronautics and Space Administration. Emphasized were investigations of the

interaction of solar corpuscular radiation and the magnetic field of the earth

and of dynamic phenomena, which may affect the operation of plasma propulsion devices. In particular, the kinetic equation was subjected to detailed

study, as was the structure of the correlation function and its application to plasma oscillations.

Theory of Satellite Orbits. Analysis of the drag-free motion of an

artificial satellite on the basis of a theory developed at the Bureau was

continued. Through the use of oblate spheroidal coordinates, it is possible

to give an analytical representation of the gravitational field of an oblate

planet, such as the earth, which is nearer the empirically accepted representation than any given previously. This permits a discussion of the motion of

a satellite in terms somewhat different from those hitherto used. A so-called

reference orbit was first established, and current work is concerned with

the study of perturbations of this orbit produced by deviations from true

oblateness, such as equatorial asymmetry and oblateness of the earth.

Operations Research. General areas of investigation during the past

year included game theory, graph theory, weapon system simulation, Boolean

functions, and mathematical models of distribution networks.

Significant progress continued on studying methods for finding maximum matchings (isolated sets of edges) in linear graphs and on extending

the results to maximum degree-constrained subgraphs. The difficulty of

the algorithms increased only algebraically (rather than exponentially)

with the size of the graph. The convex hull of the incidence vectors describing the matchings of a graph was determined. This result is unusual

in that it is not the one suggested directly by the combinatorial problem.

130
Work continued on surface imbedding of graphs, leading to an abstract

charaoterization of surface duality, and a classification of planar imbeddings.

A long-range study of mathematical models of distribution networks

continued, with a view to optimizing the locations of sorting centers and the

degree of system centralization. A number of mathematical topics relating

to the "warehouse problem" (optimal location of a single processing facility) were identified and explored. Investigations dealing with the (sometimes surprising) effects of buffer capacities in simple flow networks were

initiated. Simulation studies of two distribution subsystems were carried

out.Other major activities included continuation of the analysis and simplification of Boolean functions (important in network circuit theory) and

the analysis and simulation of missile system operation. In addition, demand for consulting and advisory services in operations research continued

to increase.

New Computer Facilities at Boulder Laboratories. The mathematics group at the Boulder Laboratories took a significant step with the

installation of a new 7090-1400 computer system. Even with the increased

capacity of the larger and more efficient system, however, the workload

has grown beyond the capability of single-shift operation. This was due

in part to the greater use being made of automatic data processing by

the Bureau's scientific and administrative staffs, and also to the extensive use of the Bureau's computation facility by other Government agencies.

These include the Bureau of Reclamation, the Geological Survey (both of

the Department of the Interior) , and the Department of Agriculture.

Mathematics Group at Boulder Laboratories. The increased computational capability obtained with the new computer system made possible

many studies by the Consultant in Mathematical Physics. These include

such studies as those of two-phase liquid flow in a pipe, Fourier coefficients

relative to attenuation measurements, and complex argument error function

for computation to high precisions.

Computational analysis programs included development of a scientistoriented computer-programming method called BOUMAC, which is in- tended to minimize programming required for certain computations. Other

projects are typified by programming computation of inverse thermodynamic

functions, computing constants for measuring network voltage insertion

ratios, and an information-retrieval project conducted for the Cryogenics

Data Center at the Boulder Laboratories.

Statistical Studies at Boulder Laboratories. Work in the field of

statistics advanced programs dealing with optimum estimation of parameters of negative exponential distribution, the distribution of a Student's t

statistic, estimating means and mediums, approximating distribution functions, and estimating parameters restricted to an interval. Applications of

probability theory were made in deriving families of power distributions

of received radio signals, analyzing variance in estimating precision of

frequency standards, modeling personnel promotions stochastically, and esti- mating parameters of Poisson distributions.

131
2.3.2. DATA-PROCESSING SYSTEMS

The Data Processing Systems Division assists other Government agencies

to use their data-processing facilities most effectively by serving as a central

research activity for data processing within the Government. It works

as a technical consultant to, and collaborator with, other agencies in planning and implementing improvements in automated handling of both numerical and nonnumerical information. To maintain its consultative facility,

paralleling the growing use in Government of data-processing equipment,

the Division must increase the competence of its staff and the versatility of

its research facilities. In providing interagency assistance, the Data Processing Systems Division

engages in research and development involving the techniques of several

scientific disciplines. Present activities include exploration of new components to determine their suitability for computer circuitry; studies of the

properties of materials; development of techniques for extending auto- matic data processing in such areas as the processing of scientific information; investigation of design procedures for assembling components into

prototype equipments and systems; exploration of the application of communication science to data processing and control systems; automatic ac- quisition and processing of data for the physical and behavioral sciences

by integrating the characteristics of the human operator with those of the

equipment; application of automatic data-processing techniques to decisionmaking functions and technical supporting services in the Government:

and the operation of a center providing information on research and development in the fields of storage and retrieval of scientific information.

More effective utilization of the many types of ADP (automatic data

processing) systems now in use or expected to be used by the Government

depends on establishment of appropriate standards, especially of input to and output from systems. Considerable planning and effort were devoted

to such standardization through both intragovernment and Governmentindustry cooperation. The Data Processing Systems Division participated

in the standardization panel of the Bureau of the Budget's ADP Advisory

Council and maintains an active staff member on the American Standards

Association's Sectional Committee X3—Computers and Information Processing and its many subcommittees and task groups. The establishment

of the American Code for Information Interchange fa 7-bit code) encouraged

the Bureau to investigate means for converting data produced in different

formats into the standard format.

Research Information Center. The Research Information Center and

Advisory Service on Information Processing, sponsored jointly by the

Bureau and the National Science Foundation, continued to collect and organize literature and bibliographic references covering a wide range of interests

in information storage, selection, and retrieval. The collection of references

to the available literature now numbers over 12,500 items. Collecting in- formation on current and proposed research projects and identifying the
research workers in. the field have been continued in order to provide such

information when requested by personnel in Government and industry.

Preliminary indexing vocabularies have been set up for selected subsets

of documents and the work of abstracting, indexing, and establishing subject

control of the pertinent literature has continued. The first 35 items of the

pattern recognition subset have been microfilmed and are now ready for

experimental subject searches on the rapid selector. Descriptive cataloging

rules and coding requirements for all items in the collection have been

formalized for full compatibility with multipurpose machine processing.

The Research Information Center issued a state-of-the-art report composed

of a bibliography of foreign developments in machine translation and in- formation processing. Two preliminary manuscripts on automated computing techniques for literature announcement media and on paper-scanning

and paper-handling techniques for use with film optical sensing devices are being edited.

A continuing literature search and survey of existing equipment and developments for printed character recognition, speech recognition, and code

recognition is being conducted under the sponsorship of the Army Signal

Supply Agency. An ancillary study deals with the special problems associated with recognition of Chinese characters ; a possible approach is by arranging each character in certain topological relationships. The center is con- tinuing to provide bibliographic and other services to cooperating workers

in the field, to Government agencies, and to interested correspondents.

Components and Techniques. The study of new and existing components continued as basic to developing economical, higher speed, more reliable, efficient digital data-processing devices having lower power requirements.

The importance in a system of the capability of producing fast rises and

of measuring and resolving extremely short durations (e.g., one nanosecond)

led to the study of ultrathin ferromagnetic films as potential high-speed ran- dom access memory elements. This in turn involved studies of a strip

transmission line for producing drive fields and a sampling oscilloscope for

measuring switching signals.

The technique of quantitative analysis of thin films by X-ray fluorescence

also was studied. A new hysteresis loop tracer was designed and constructed

for measuring the dispersion of the anisotropy axis in films. In this con- nection a study was made of the electronic integration methods used in

making these measurements. Preliminary results indicate that the fidelity of

the hysteresis loop presentation is significantly improved by a phase-compensation circuit in the integrator.

The characteristics of semiconductor devices, such as tunnel diodes and

mesa, microalloy diffused, and epitaxial transistors, were studied by use of

simulation techniques. A charge control model of a junction transistor was

simulated on an analog computer to determine the best way of driving a switching transistor. The use of tunnel diodes and transistors was surveyed

for very fast logic circuits. A counter circuit capable of counting up to 80

megapulses was developed, based on an 80-Mc/s triggerable flip-flop multivibrator incorporating tunnel diode-transistor circuitry.

133
In studying semiconductors and storage devices for memory and logical functions in computers and control circuits, the binary computer net was reappraised and the general computer requirements described mathematically in terms of digital repeater transfer functions. The description,

considerably extended and refined, does not specify physical form or logical

organization; this offers the prospect of comparing and evaluating, in com- mon terms, computer nets differing widely in physical and logical aspects.

Scientific Information Processing. The development of a programming system for processing information-retrieval prescriptions, directed at information sources consisting of interrelated pictures and text, was con- tinued under the sponsorship of the Patent Office and the National Science

Foundation. A prototype system accepting English sentences which describe pictures of simple geometrical shapes was developed ; it directed

manipulation of the sentences and pictures to determine which sentences were correct descriptions of which pictures. This program used a generalpurpose syntactical analyzer for phrase structure grammars, written for

the 7090 computer. A machine grammar written for the relevant fragment

of English was used as the basis for others, including larger fragments

of English. A set of programs for anlysis of simple pictures was constructed

in STRIP (a machine language developed for the SEAC). Finally, an

algorithm was written for translation of analyzed sentences into a logical

calculus.

Logical and mathematical investigations were conducted, also under

the sponsorship of the Patent Office, on some aspects of the organization

of scientific and technical information that relate to methods of classification, storage, search, and retrieval, for automatic information systems.

Additional studies required for the picture-description matching program

concerned flow problems, the structure of generalized matching of graphs,

Boolean matrices, binary relations, and the formal aspects of disaggregation

as related to forming interest classifications in models of information systems.

The project of mechanizing Patent Office searches for chemical compounds

has reached the point of a completed experimental file of chemical structures containing 2400 entries. The encoded data cover more than 160,000 or- ganic compounds. The HAYSTAQ search routine was operated on this

file to test the search logic and determine areas of possible improvement,

using about 385 different questions. Studies of the most frequent errors and variation in error sources were based on analysis of key-punching output

and computer-based error checking. Research on file organization continued with the development of screening methods permitting increased

search efficiency.

Ciphering rules originally developed at the Patent Office for representing

chemical structures simply and uniquely were revised and expanded jointly

by the Bureau and the Patent Office. Use of the rules was simplified and

they were made more widely applicable, now covering, for example, optical

isomerism and isotopic labeling. The rules are being expanded to include

inorganic structures, further types of polymers, Markush (variable) struc134
tures, and partially indeterminate structures. An experiment is under way

to test the adequacy of ciphers for data input and as the basis of screening

and searching. The logic was worked out for a number of the manipulations necessary on the ciphers, and some preliminary computer runs were made.

An overall systems design was prepared for the Office of Technical Services (Department of Commerce) to aid it in managing the information

associated with acquiring, advertising, and disseminating the report litera- ture stemming from Government-sponsored research and development. The

plan includes progressive mechanization of index preparation, announcement

composition, processing requests for documents, inventory control, and

processing documents into the OTS collection.

An experimental computer program for producing a permuted title index

of technical reports is now completed. Another program operating on the same input was written to produce indexes by subject, corporate source,

series number, contract number, and author.

Sales statistics were gathered, and orders and incoming correspondence were sampled to evaluate demand as a factor in determining prestocking

and reprinting requirements. Information to give indications of user pref- erence, ordering habits, and responsiveness to prices was also developed and

evaluated. Based on this information, work was continued on the design of

the mechanized order-processing system to incorporate inventory mainte- nance and control and the ability to produce operational statistics. The design of a central machine file to simulate the functions of a massive

card catalog was begun. The data-preparation scheme, the file-building

programs, and the file-maintenance programs are sufficiently advanced for

use in the various index programs and parts of the analyses of sales, users, and inventory.

Technical Assistance for Data Processing. Expanded assistance to

laboratories at the Bureau identified potential areas for automatic data re- cording and processing, many of which had special data-logging and preprocessing problems. Technical assistance was provided following analysis

to determine whether analog or digital techniques were applicable, after

which the feasibility of the selected applications was demonstrated. Examples are the modular data-logging systems designed for use in experiments concerning the radial properties of magnetically contained plasma

arcs formed at low and near-atmospheric pressures.

The program of developing modular units of data-logging equipment

for use by other laboratories included the design, construction, and evaluation of the following modules: a digital multiplexer functioning as a 64-pole,

three-position switch when used in conjunction with the shift register; a

block reader reading punched paper tape in 12-character blocks; a relay

register storing 16 four-bit characters in terms of relay contact positions;

a ripple register storing up to 10 characters in a way permitting convenient data rate buffering; a counter interface matching the control and data

signals of a commercial counter to the modules; a control auxiliary con714-691 0—64 10 135
taining counters. flip-Mop multivibrators, and one-shot multivibrators used

in system control; an incremental digital magnetic tape recorder; and special

modules providing nonstandard functions unique to an individual system.

The use of a data processor in a real-time data-logging system was investigated for multiparameter experiments in nuclear physics. Assistance

in the logical design of input instrumentation, consisting of converters,

counters, timers, and buffers, was provided to the NBS Betatron Laboratory,

and drawings and wiring tables were prepared. Programming assistance was also furnished in developing routines for handljng the input data, pre- processing, output, and the various forms of display. Methods of setting

up and modifying the experiments are being considered, including a flexible

system for reassigning priorities to four simultaneous experiments.

Information-Processing Systems. A remote inquiry station was designed for the Patent Office to provide easy and rapid communication between

human operators, at their respective locations, and a central data processor. The design is such that the locations could be within one building

or separated by distances of hundreds or thousands of miles. The remote

station design includes a console with a keyboard for encoding messages, a

visual display similar to a television picture, means for error correction and

control, a local memory, a transmission buffer, and a printer. The design

is compatible with the data-logging system requirements anticipated at the

Bureau. Alternative data-storage devices were investigated, and magnetostrictive delay lines were selected as meeting all operational requirements.

Assistance was provided in the development, under the sponsorship of

the Navy's Bureau of Supplies and Accounts, of an efficient system for the

procurement and distribution of the thousands of items within the Naval

establishment by controlling their purchase, storage, and distribution. The

present and planned functions and requirements of the systems were

analyzed, and the characteristics of the equipment needed to be in- corporated in the new system were determined. Programs for an in- terrupt-type of entry into the Newport Supply Depot from Boston were

assembled, the availability of suitable equipment was studied, and a minimum system was designed and partially tested. A dial-box entry device was designed and a prototype is being constructed. A system concept for

computer operation to intergrate the entire Naval Supply System is under

development and points of trade-off between methods of operation and

communication loads were noted.

A modest information-handling system was designed for the Naval Intelli- gence Agency to provide an efficient, low-cost means of storing, searching,

and retrieving intelligence data. The design incorporates a modified microfilm camera, an eight-channel keyboard, paper-tape reader and punch for

input-output, a viewer modified for printing, a magnetic drum memory, a camera modified for one-to-one microfilm copying, and custom-built plug-in

electronic modules. Assistance was also provided in the development of a more efficient coding scheme for indexing the files.

136
Information handling system designed for the Naval Intelligence Agency as a

low-cost means of storing, searching, and retrieving intelligence data. (See

p. 136.)

The design, development, and construction of ACCESS (Automatic Computer Controlled Electronic Scanning System), a high-capacity, multipurpose data-conversion and data-editing system, were continued. ACCESS

is being made under the sponsorship of the Office of Emergency Planning

for handling resource evaluation and status information. The system is primarily to gather and prepare data from marked documents; it is an advanced development of the FOSDIC (NBS-Bureau of the Census) and AMOS

IV (NBS-Weather Bureau) systems that will, when completed, serve civilian

defense needs.

The data processor is designed to control not only the scamper but also

communication facilities, pen plotters, and multiple tape units. It performs

such operations as table lookup and memory intertransfer, rendering it adaptable for code conversion, verification, editing, reorganizing, screening,

control of input-output devices, and preparation of output messages. The

central data processor and the flying spot scanner and control of the system

are now completely constructed while the plotter system, communication

portion, and magnetic tape control unit are designed.

The application of automatic data-processing techniques to processing

hydrographic data, from shipboard data logging to the production of charts, was studied for the Coast and Geodetic Survey. Specifications for a dataprocessing system incorporating a computer and peripheral equipment were

prepared for the Survey as the basis for procurement.

137
The Air Force Systems Command sponsored the beginning of a longrange project to develop plans and specifications for an information-processing and information-control system of a worldwide range for support of

future orbital and space programs. Basically, the system must provide means for optimum effective use of instrumentation, communications facilties, and central control, obtaining mechanization of the range "countdown,"

coordination of instruments at all stations, processing data at remote sites,

and controlling the flow of commands and reports in communications links.

Preliminary work was conducted, specific problem areas were delineated,

and work was begun toward the establishment of absolute time on a global

basis

Engineering Applications and Devices. Technical assistance to the

Defense Communications Agency was continued to devise and use a computer program simulating the Defense Communications System. The DCS

controls a worldwide communication system, a composite of the separate

long-line communication systems of the three Services, providing communications for defense and related organizations regularly and during emergency.

The Bureau provided consulting services on the performance simulation

model of the network being developed by a contractor, and undertook charting the inputs and programs required in the simulations, permitting analysis

of vulnerability, recuperability, performance, and economics.

Advisory services were provided to the Bureau of Naval Weapons in con- nection with its contracts for research in the area of direct digital encoding

devices. Two developments were considered: a digital pressure transducer on which assistance was given on the digital logic circuitry and mechanical

characteristics of the pressure-sensing elements, and a unique coding device

utilizing the varying electric field on a conductive substrate.

A data-logging system for sampling and compiling analog and digital data

into a format suitable for transfer onto magnetic tape was extensively modified for the Army's Harry Diamond Laboratories. Analog information can now be transcribed by it onto magnetic tape in IBM format. This

equipment is for use in the collection of experimental data throughout the

laboratories.

A prototype personnel peer-rating machine, for rapid performance meas- urements and evaluations of leaders, was designed and a prototype delivered

to the Army Personnel Research Office. This machine is now scheduled for

comprehensive evaluation at the Army Training Command, Fort Ord, Calif.,

under actual conditions of use. The Vigilometer, a versatile laboratory device for presenting audio and

visual questions to a human being and recording his responses, was designed

and a model is now under development. The system is intended to determine the alertness of the human in a control loop and his fatigue threshold.

Detailed engineering specifications were prepared, and fabrication and

wiring are more than half completed.

Special Studies and Analyses. Research and development on techniques for scanning serial stereophotographic information were continued

138
under the sponsorship of the Naval Training Device Center. The object

of this program is to use the scanned information for automatically producing three-dimensional terrain information. The input material, in the

form of a photograph or other pictorial material up to 9 in. X 9 in., is scanned

by an experimental drum scanner linked to an analog-to-digital converter. The magnetic tape output obtained represents each successive 0.005-in.

square picture element by one of eight gray-scale levels. Several test programs for the IBM 7090 computer were written to process

the magnetic tape carrying the encoded pictorial data. These programs

analyze the digital data and present the information in various ways—spotby-spot detail, a list of runs, a three-line average, a basic eight-level pictorial

printout, experimental four-level and five-level pictorial printouts, and a list- ing of key trend points.

The Bureau provided consultative services to the Weather Bureau, both in

activating Automatic Weather Stations previously developed by the Bureau

and in transmitting and processing photographic data transmitted by the

new weather satellites of the NIMBUS series. The NBS services included

a review of the Weather Bureau data-processing capabilities and an investigation of techniques for producing large photographic cloud history archives.

The U.S. Air Force requested and received assistance in the evaluation

of two contractor proposals. One was for the design, manufacture, and

installation of a General Purpose Automatic Test System (GPATS) for

Rapid measurements of performance, and evaluations of leaders can be made

with this prototype personnel peer-rating machine developed for the Army.

(See p. 138.)

139
more effective depot level maintenance of modern airborne electronic systems.

The other was for proposed designs for a Versatile Automatic Test Equipment (VATE), to be used in the repair and testing of the Inertial Guidance

System, making the most of versatility and standardization of test equipment.

The continuing study of the system requirements for automatic data

processing at NASA's Goddard Space Flight Center concentrated on a survey of commercially available magnetic tape-to-tape digital data-transmission systems. Technical advice regarding interconnecting the several NASA

computer facilities via high-speed data links was given, including recom- mendations for microwave transmission equipment and high-speed data

terminals.

Management Data Processing. Technical assistance was continued

to the Public Housing Administration concerning data-processing techniques

and programming for reports on housing applications. The computer programs were revised to reflect the requirements of new legislation concerning

the administration of Federal-assisted, low-rent housing. Data about applicants for tenancy in low-rent housing, in addition to data about tenants

already in residence, are submitted by the local housing authorities for

annual review to determine tenant eligibility. New computer programs

were written for processing data on approximately 500,000 reexaminations

and 120,000 new tenants annually.

The activities and operations of the Interstate Commerce Commission were

analyzed to determine the areas in which the use of automatic data-processing

techniques was feasible. Systems and computer programs were designed

for applying these techniques to cost-finding studies of motor and rail

transportation, for providing information on authorities granted to motor

carriers, and for obtaining information on caseloads and the time required

for administrative proceedings.

Automatic Mail-Sorting Developments. The Bureau continued its

assistance to the Post Office Department's Office of Research and Engineering

in applying automatic data-handling techniques and equipment to mailsorting and route-selection operations. A revised computer program was

developed for selecting optimal paths for routing mail, using scheduled

transportation links. The new program, designed to aid in a semiannual

problem, can handle 84 nodes (airports) and 2000 links (scheduled trans- portation segments).

A procedure for partitioning transportation networks was developed, in

which the network is considered as a graph which can be divided, by the

elimination of selected nodes, into several subgraphs having no common

points. This demonstrates that a large variety of transportation networks

can be partitioned by the elimination of a surprisingly small percentage of

the nodes. Work in this area should lead to procedures for determining

optimal paths when handling larger networks.

The study of updating files in a codesort system was continued, and

an improved procedure developed for updating the incoming file. Programs

were written enabling the computer to use these files in preparing standard

140
Post Office documents.

The network study of the sorting and transportation problem was continued

and a mathematical model developed to represent the important properties

of a postal transportation network. Further assistance was given to the

Post Office Department in the technical monitoring of a large-scale simulation

project and human factors study.

2.3.3. INSTRUMENTATION

The Bureau is concerned with both the theory and practice of measurements; its practical work is aimed at improving both industrial technology

and the Bureau's own research programs. Since measurement precision

depends on the natural limitations of the method and the behavior of practical instruments, both are being investigated to advance the measurement

art.The Bureau maintains an extensive reference file of literature on instruments and measurement methods to help disseminate measurement information and avoid duplicating scientific research effort. The file is designed

so that its data can be retrieved partly by mechanical means. Simple techniques insure good coupling between the researcher and the file, so that the

researcher is led quickly to relevant information.

Mechanical instrument activities include responsibility for the national

standards of humidity and for improvement in standard hygrometers and

humidity generators. Calibration methods are being developed for pressure

and acceleration transducers, while other mechanical instruments are being

developed to meet specific Federal agency needs.

Electrical and electronic methods are widely used in modern instrumentation, even when the initial phenomenon being measured is not electrical in

nature. Electronic methods were devised to investigate the characteristics

of materials used in vacuum and semiconductor electron devices and the

behavior of very high vacuum systems, as well as the characteristics and

capabilities of electron devices themselves. Improved electronic instruments were developed not only for use in Bureau research programs but also for

use by other Federal agencies.

Failure Anticipation by Semi-Automatic Techniques. For a number of years, the Navy Bureau of Ships has supported an NBS program for

developing electronic equipment fault-location techniques. The success of

work in the fault-location project led to new thinking on the old idea of a

failure-anticipation system, an area demanding of development efforts.

Electronic equipment failures can be anticipated by recording and analyzing equipment performance data. The failure-anticipation methods developed at the Bureau do not employ computer techniques or special interpreting

equipment, and thus are relatively simple and versatile. After the recorded

data are used for anticipating failures, they can be put to further use in

studies of equipment reliability. Such analysis of recorded performance

data should permit identification of incipient troubles before they become

major problems.

141
In project FIST, a system for testing and maintaining modularized electronic

equipment was developed which requires no more than bulk-changing skill on

the part of the maintenance personnel. (See p. 141.)

Hall Effect Measurements. The Hall effecl, in which a potential is induced by current flow across a magnetic field, was discovered in 1879

but only recently became widely used in electronic instrumentation. The

present popularity of Hall devices led the Bureau of Naval Weapons to sponsor a program at the Bureau to establish standard measuring methods

and terminology for Hall effect devices.

A proposed standard for Hall generator definitions, terminology, letter symbols, and graphic symbols is in preparation. Included are definitions

of linearity error and descriptions of measuring methods. The Bureau

joined in organizing a meeting of the American National Committee for

the International Electrotechnical Commission (TC 47) to prepare an American proposal for Hall-device standards. The military standard prepared

by the Bureau for the Department of the Navy was used as a basis for the

American proposal.

Instrumentation using electron paramagnetic resonance to measure small

magnetic fields in restricted areas is being developed.

Vacuum Physics. Precise measurement techniques in the very high

and ultrahigh vacuum regions are urgently needed, particularly for studies

of particle density. The program is now concerned with obtaining more

precise measurements of conductance at these low pressures, to make possible

better understanding of particle distributions and accurately known con- ductances to be used as reference standards for ionization gage calibration.

Substitution techniques are being studied for measurement of vacuum flow,

since substitution methods are in principle independent of detector charac142
teristics, gas species, and temperature. Successful use of substitution depends

upon good detector sensitivity, lack of detector hysteresis, and on calibration and resolution of the variable conductance against which the unknown

is compared. A scheme for calibrating the variable conductance against

zero-thickness orifices was evolved, and glass rotary valves with specially

shaped orifices were produced as variable conductances. Ion gage emission was regulated to 0.1 percent. An experimental vacuum line with these

components demonstrated that changes in the variable conductance of 0.1

percent and changes in. pressure of less than 0.1 percent at 5X10~6 torr can be resolved. This resolution indicates that substitution procedures are

feasible.

A Photoelectric Ratio-Measuring System for Incident Light.

Measurements of absolute light intensity at selected points are normally

subject to the effects of fluctuation of the source during the measurement

period. In developing an instrument for measuring the field distribution of

bremsstrahlung radiation from a synchrotron, the electronic instrumentation

laboratory developed an instrument for measuring the intensity at a fixed

point relative to that at another position. The ratio of the two fluctuations

originating at the common source must be independent of source fluctuations

and must be due to variations in either of the two flux paths.

In the ratio-measuring instrument one phototube was fixed in the light

beam and the other mounted behind a slit that could be moved across the

beam. The ratio of the measured quantities gave a relative amplitude plot

of the radiation beam that was independent of random fluctuations at the

source. The light flux arrived at each phototube in the form of pulses.

Variable gating circuits allowed independent selection of the measuring

interval within the radiation pulse cycle. Ratio measurements were made

with a modified strip chart recorder; digital voltmeters also can be used for

ratio indications.

A precision electronic integrator was developed as a companion unit to the ratio-measuring instrument for absolute measurement of radiation yield

by derivation from a time-integration of photoelectric current. The inte- grator has a time constant of about 10 days; thus a charge on the integrating

capacitor decays at a rate of about 0.5 percent per hour. Linearity as checked with a timer and a digital voltmeter is approximately ±0.01 percent.

Proportional Temperature Controllers. The first work on proportional control of temperature by the Electronic Instrumentation Section was

begun in 1947. Since then, 16 different models of temperature-control

instruments have been developed for laboratory use within the Bureau. Each

new model has represented an improvement in accuracy, dependability, or

versatility.

Present systems using resistance thermometers can react to a temperature

change as small as ±0.001 deg C to produce a compensating control of

heater power. It is possible to increase this sensitivity to differences as small as ±0.0001 deg C. Many systems having high sensitivity react unstably, however, producing a periodic oscillation in temperature. Thermal

143
time lags in the controlled environment are one source of such instability,

so the environment must be designed carefully if high system sensitivity is

to be obtained.

Recently designed controllers use thermistors as temperature sensors be- cause of their high sensitivity and low cost. Their electrical stability is questionable, however, so they are currently restricted to applications re- quiring a control accuracy no better than ±0.01 deg C. The newer controllers have the advantage of adjusting heating power continuously, as opposed to older systems using on-off, or time-proportional, control.

Replacing vacuum tubes with semiconductor devices made temperature

controllers much more reliable. Transistors, for example, operate at lower

circuit voltages and with less internal heating. Future work is directed

toward even simpler and more reliable designs.

Hygrometry. The Bureau completed the development of a pneumatic

bridge hygrometer which is suitable for use as a secondary or laboratory

reference standard. This instrument contains four critical-flow nozzles,

with a pressure manometer across the bridge, and a desiccant in one branch.

The differential pressure across the bridge is a measure of the moisture conPneumatic bridge hygrometer developed for use as a secondary or laboratory

reference standard for humidity measurements. (See p. 144.)

144
tent of the test gas flowing through the bridge. The bridge was calibrated

against the NBS gravimetric hygrometer; in the range of 0.6 to 19 mg water

vapor per gram of dry air, it measures the humidity of the test gas (in

terms of mixing ratio) with an accuracy of ±0.06 percent of full scale. A preliminary intercomparison between the Bureau's two-pressure humidity generator and the Bureau's gravimetric hygrometer reconfirmed

that the generator produces atmospheres of known mixing ratio with an

accuracy of ±0.5 percent or better.

Electromechanical Transducers. The Bureau is engaged in a con- tinuing study of the behavior and performance of electromechanical trans- ducers, particularly pickups sensing such parameters as pressure and ac- celeration. This program is jointly sponsored by the Bureau of Naval

Weapons, the Air Force, and the National Aeronautics and Space Administration.

An experimental technique using shock tube excitation was developed

for obtaining the resonances, particularly the lowest one, for a variety of

flush-mounted, high-frequency pressure transducers. The technique consists essentially of subjecting the transducer to a pressure step function

inside a shock tube. The transducer output is applied simultaneously

to an oscilloscope (for a photographic record) and to a magnetic drum

recorder. This recorder preserves the transducer's indication for repeated

playback into a spectrum analyzer. The analyzer produces a histogram

showing the frequency components present in the transient and, roughly,

their relative amplitudes.

Selected transducers were calibrated, tested, and evaluated to keep

abreast of the newest commercially available pickups and to determine the

adequacy of test methods and equipment.

Instrument Reference Service. Industrial and Government scientists

developing instruments of any kind must know what has already been done

in the same area in order to design without duplication of effort. A scientist

seeking information on work already done in his field can make inquiry

of the Instrument Reference Service, one of the Bureau's reference and consultation services for scientists.

The Instrument Reference Service enlarged its card index of instrumentation literature by selecting, analyzing,, coding, and recording additional in- formation on the special punched cards of the "peek-a-boo" system. Inquiries are answered by means of the index and other information resources. A number of improvements in the indexing system were made: a simple

photographical method of reproducing sets of punched cards was developed.

This not only facilitates replication, but the positive and negative copies obtained can be assembled as logical-sum and logical-negation searches. Microcite, the information-searching machine developed at the Bureau several

years ago, now is in routine operation performing searches for instrumentation information. An improved machine having a potential search capacity

of millions of abstracts is now under development and will be tested in use during the next fiscal year.

145
2.3.4. RADIO PROPAGATION

The Central Radio Propagation Laboratory (CRPL), 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 atmosphere,

and in space. Some work of the Bureau is international, both in the origin

of data and because it is performed in cooperation with scientific groups of

other countries. This is particularly true of CRPL's participation in the

recent International Geophysical Year (IGY) program and in the International Years of the Quiet Sun (IQSY) program to take place in 1964 and

1965.

IQSY. Several members of the CRPL staff are participating in planning the scientific programs for IQSY. CRPL also prepared the Manual

for World Days Program and the International Geophysical Calendars for

IQSY. These provide the framework for coordinating many aspects of the

scientific programs recommended for each of the IQSY disciplines: meteorology, geomagnetism, aurora, airglow, ionosphere, solar activity, cosmic rays, and aeronomy. The details of these programs call for special observations on certain days during IQSY or special treatment of the data obtained. The

rapid communications necessary during the World Days program will be

obtained by channeling messages principally through Regional Warning

Centers (RWCs). The North Atlantic Radio Warning Service at Fort Belvoir, Va., will serve as the Western Hemisphere RWC, and also as the World

Warning Agency responsible for declaring Alerts, days of special geophysical

interest.

The World Data Center-A for Airglow and Ionosphere was relocated and

plans made for handling the high rate of data inflow which will begin with

the IQSY. Microfilming is being considered to improve cataloging and

provide rapid availability of data. All incoming data will be immediately

copied, and the routine exchange of data made on microfilm. The volume of

requests for IGY data has remained high during the past year, indicating

the continued need of this service by the scientific community . IONOSPHERE RESEARCH AND PROPAGATION

The Bureau conducts and coordinates research on the propagation of

radio waves as affected by the ionosphere and on the special factors (such

as solar flares) which can give rise to large departures from the normal

behavior. It is also concerned with research on the nature of the media

through which these radio waves are transmitted and the interaction of radio waves with the media. One of the important functions of the Bureau is the preparatiaon of predictions of radio wave propagation and warnings

of solar and geophysical disturbances.

Geomagnetic Micropulsations and Infrasonic Pressure Waves.

An experiment combining measurements of geomagnetic micropulsations and

infrasonic pressure waves was carried out in the auroral zone at Fort Yukon.

146
Alaska, during August 1962. The results supported the supposition that

infrasonic pressure waves having periods of 10 to 110 sec and amplitudes

of one to 10 dynes/cm2 have their source in the auroral region. (For a

report on study of infrasonics of other periods.) They are also associated

with geomagnetic micropulsations in the same period range, with ionospheric

absorption, and with fluctuations of the auroral electrojet. The micropulsation pressure front was found to arrive nightly with a consistent time

and directional relationship to the east-to-west progression of the auroral

activity maximum. Despite the general relationship, it was not possible

to find identical geomagnetic micropulsation and infrasonic excursions.

This was interpreted to be a result of reception of infrasonic pressure

signals from nonlocal sources, causing the indication of infrasonic activity

to precede the local auroral activity in the early evening and to extend later

into the morning hours. Variations in the auroral ionospheric heating,

initiated by the local electron bombardment, and perhaps through auroral

electrojet joule heating fluctuations, seem to be a source of auroral zone

infrasonic pressure variations.

These phenomena were investigated by making around-the-clock measure- ments at Fort Yukon and College, Alaska. Measurements were made at both stations of infrasonics activity index, changes in riometer absorption

from the "quiet day" value, variation of magnetic field from quiet day

value, and geomagnetic micropulsation activity of period 5 to 30 sec. Lunar Tide Effect in the D-Region. The presence of a semidiurnal

lunar tide in the daytime Z)-region of the ionosphere (at a height of about

70 km) was established for the first time. The lunar tide produces a variation in the height of radio reflection of approximately 0.2 km along VLF

radio paths between Panama (Canal Zone) and Boulder (Colo.). A comparable value was obtained for the Hawaii-Boulder path. The maximum

height change resulting from the lunar tide occurs two hours before lunar

transit. This work was sponsored by the Department of Defense Advanced

Research Projects Agency.

Effect of VLF Propagation on Standard Frequency Transmissions. Recently, VLF radio transmissions have been employed in the comparison of standard frequency oscillators separated by great distances, such

as between various countries. In applications of this type it is of major

importance to determine the errors introduced by the propagation medium.

This has been done by measuring the accumulated phase difference between

an accurately controlled VLF transmission and a local reference oscillator.

It was assumed that any frequency difference between the transmitted VLF

signal and the local oscillator, after correction for known frequency changes,

increased linearly with frequency. The precision of the frequency comparison was then found to be 4 X 10~10 for observing periods of 1 hour and

at least 3 X 10~12 for periods of 300 hours.

If these errors are not due to differences between the oscillators being

compared, they must be due to the propagation medium. Thus, the figures

147
given represent upper limits to the errors introduced by the propagation

medium for the particular path being observed.

It is interesting to note that the lunar tide mentioned above can introduce appreciable errors in short-term frequency comparisons. The error introduced along the Canal Zone to Boulder path, for example, could be as much as 2X 10"" during a 6-hour frequency comparison when the path is

sunlit. This work was sponsored by the Department of Defense Advanced

Research Projects Agency.

Ionizing Processes in the D-Region of the Ionosphere. Observations of the diurnal phase change on long VLF paths at medium and high

latitudes show that the reflection height of the ionosphere drops almost

immediately when the lower ionosphere becomes sunlit. It remains at the

low level until darkness occurs and then rapidly returns to the nighttime

height. Observation at Tucuman, Argentina, of VLF transmission from the

Canal Zone over a path crossing the magnetic equator, however, shows a

quite different diurnal variation. Near noon the height of reflection shows

a dependence on the zenith angle of the sun, averaged over the path. This

may confirm suggestions that were made concerning the ionizing influence

of cosmic rays in the lower ionosphere. This contribution would be much

reduced near the magnetic equator, according to the suggestion, leaving only

the effects of the sun's ultraviolet and X-radiation.

It is well known that solar flares produce sudden reductions in the height

of reflection of VLF signals during daylight hours. It was recently discovered that nighttime reductions of height also occur in association with

magnetic bays. There is a tendency for such events to occur at latitudes

where precipitation of electrons from the outer Van Allen radiation belt

would be expected.

Ionospheric Predictions by Numerical Mapping. The recently developed Gallet-Jones method of numerical mapping of ionospheric characteristics by modern electronic computer methods was adopted and applied

to the CRPL ionospheric radio propagation predictions. For almost 20

years the CRPL Series D prediction charts, prepared by manual and graphical methods, have been standard tools of Government and business communication services in the United States and abroad. The predictions are used in designing communication systems and for frequency planning and

allocation purposes, to ensure the most efficient use of high frequencies.

The new series of CRPL Ionospheric Predictions, which replaces the

former Series D prediction charts, uses numerical prediction maps in two

forms. Tables of predicted numerical map coefficients are provided for

large users which have computing equipment enabling them to make effective use of the speed and economy of electronic computer methods in applying

the predictions to communications problems. The predicted coefficients are also available in punched card form for more efficient computations.

World maps of the ionospheric predictions are provided to the small scale user for the manual solution of communications problems. Polar prediction

maps also are available for specialized high-latitude applications. Not onlyUS
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The monthly NBS radio propagation predictions are now being prepared by

recently-developed numerical mapping techniques with an electronic computer,

and the data is presented in special form for easy input to computer. Graphical

prediction maps (above, for October 1963) are still provided for users who

have no access to a computer. (See p. 148.)

are the new predictions believed to be more accurate than the older type, but

they are also much more versatile for adaptation to individual problems.

First Topside Sounder Satellite. As a part of an international cooperative program to probe the topside of the ionosphere, the National Aeronautics and Space Administration launched the Alouette topside sounder

satellite into a nearly perfect orbit on September 29, 1962. The orbit is

inclined 80.5° to the equator and it is almost circular between 995 and 1030

km altitude. The topside sounder was designed and constructed by the

Defense Research Telecommunications Establishment (DRTE) of Canada

and is controlled by it. It consists of a swept-frequency sounder covering the

range of 0.5 to 11.5 Mc/s in 18 sec. The sounder operated perfectly

following the launch and since then it has produced more than 400,000

ionograms. Such ionograms show the heights at which downward transmitted signals are reflected by the ionosphere as the signal frequency is swept

across its range. The Alouette data are being analyzed jointly in Canada

by DRTE, in the United States by CRPL and NASA, and in England by the

Radio Research Station at Slough.

The high inclination of the Alouette orbit permits study of the topside

of the ionosphere over a very wide range of latitudes from the northern polar

region to the southern polar region. Analysis reveals, among other things,

a transition from atomic oxygen ions to lighter ions at about 600 km at

149
temperate and low latitudes, as well as a tendency for the polar regions to be substantially warmer than the tropics. The topside sounder has observed

irregularities in the ionosphere varying in size from a fraction of a kilometer

to hundreds of kilometers.

The Central Radio Propagation Laboratory is also involved in a second

topside sounder satellite, which has been constructed under NASA contract

by Airborne Instruments Laboratory. This instrument, a fixed-frequency

sounder operating at six frequencies between 1.5 Mc/s and 7.2 Mc/s, will

be operated by CRPL under NASA support. It will be launched by NASA

on an improved Scout rocket, into an orbit similar to that of Alouette, early

in 1964. Originally set for late 1962, the launch has been delayed several

times, both to avoid solar cell damage resulting from the artificial radiation

belt created in 1962 and to permit further improvement of the experiment

in the light of results from the first topside sounder satellite. Planetary Ionosphere. Recent theoretical estimates of the composition of the Martian atmosphere, based on 2 percent COv and 98 percent N2 , indicate that the Martian ionosphere occurs at a greater height than does

the earth's ionosphere, but at about the same pressure. The maximum elec- tron density for an overhead sun is probably between the density of the

terrestrial E- and F2-layers, that is, between 105 and 106 electrons per cm3. There may be, in addition, a layer that absorbs radio waves much more

strongly than the normal terrestrial Z)-region.

Assistance to Project Mercury. During the orbital flights of Astronauts Shirra and Cooper, special efforts were made by the staff at the North

Atlantic Radio Warning Service located at Ft. Belvoir, Va., to keep Project

Mercury headquarters informed of current and anticipated radio propagation conditions. Special forecasts of radio propagation conditions were

issued every hour during the flights, specifically for the high-frequency circuits which comprise the Project Mercury ground communications network.

The forecasts were made available to the NASA Communications Director

and the Propagation Analyst at the Goddard Space Flight Center communications center. During the periods between orbital flights, forecasts were

issued by the Warning Service staff weekly, with daily updating as necessary.

Reliable forecasts were made possible by associating reports of observed

propagation conditions on each Project Mercury circuit with reports of

observed solar, geomagnetic, and ionospheric activity occurring at the same

time. This work is performed under a Memorandum of Agreement between

the National Aeronautics and Space Administration and the Bureau.

The propagation forecasts supplied by the North Atlantic Radio Warning Service enabled the Mercury ground communications center to anticipate problems that might be encountered and select alternative frequencies or circuits to insure unbroken communications. This reliability of communication was required in obtaining information from the astronaut and spacecraft equipment, which was telemetered to the tracking stations and relayed

to the Mercury Control Center at Cape Canaveral. The same reliability was

required for transmission of decisions from the Mercury Control Center

150
MERCURY COMMUNICATIONS NETWORK

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Special forecasts of radio propagation conditions were issued by the Bureau

every 30 minutes during the orbital flights of Astronauts Schirra and Cooper.

Such information was essential to effective communications between Mercury

control at Cape Canaveral and other Mercury stations around the world. (See

p. 150.)

to the tracking stations and the capsule itself, to insure the safety of the

astronaut and the success of the mission. The staff of the North Atlantic

Radio Warning Service received congratulatory telegrams from the National Aeronautics and Space Administration for its role in making the

missions successful.

Ionospheric Ray Tracing. Ionospheric ray tracing, which takes the

earth's magnetic field into account and allows for a "two-dimensional

ionosphere" (one with the horizontal gradients along the great circle path

of propagation) , is now possible with a new 7090 computer program. This

program is basic to an improved understanding of ionospheric propagation, since its output includes step-by-step evaluation of the ray path. It

can also be applied to theoretical studies of the phase, amplitude, and

frequency of ionospherically propagated radio waves.

This research has been supported partly by the United States Information

Agency and partly by the Air Force Cambridge Research Laboratories.

Operation Fish Bowl. During the past year a number of measure- ments were carried out for the Defense Atomic Support Agency and other

agencies in connection with the 1962 series of high-altitude nuclear tests,

Operation Fish Bowl. Many complicated technical, logistic, and personnel

problems were met and successfully solved on short notice.

714-691 O—64 11 151
Among the variety of support activities, six ionosphere stations were

set up and operated and VLF phase measurements were made over a numher

of paths. Observed perturbations of VLF phase following the blast of

July 9, 1962, are attributed to a lowered reflection height in the D region of

the ionosphere, which produces an advance in the phase of the received

signal. Such effects were produced in signals passing through regions illu- minated by prompt X-rays from the detonation. Effects observed several

thousand kilometers from the detonation probably were associated with the

neutron-beta decay process.

Also, the North Pacific Radio Warning Service at Anchorage, Alaska was able to observe unusual effects on high-frequency field strength and

on the strength of cosmic noise recorded by a riometer following the

shot. The detonation times were announced by telegram to geophysicists

throughout the world through the facilities of the World Warning Agency

of the International Ursigram and World Days Service. Thus experimenters

the world around were able to study their records for effects of the explosion.

On the occasion of the July 9 event, high-frequency signals being re- ceived at Anchorage were lost at the instant of the detonation. Recovery

began within a few minutes, but 20 minutes later there was again evidence on the records of a further increase in absorption. This second onset was

clear on both the riometer recording and the field-strength records. The

source of this later absorption is of considerable interest. Analysis of such

events should lead to better understanding of processes taking place in the

Z)-region of the ionosphere. This work was sponsored by the Department

of Defense Advanced Research Projects Agency.

Thermal Properties of the F-Region. Measurements of ionospheric

electron distributions at 11 widespread locations during the International

Geophysical Year and 1959-1960 have provided valuable data on the solar,

seasonal, and diurnal variations of the F-region. The temperatures inferred

from the curvature of the F2-layer peak are uniform at all latitudes in the

presunrise period and show a steady diminution with decreasing solar activity. Daytime measurements suggest that the electron temperature exceeds

the ion temperature at the height of the F2 peak, the ratio Tr /Ti increasing

with latitude and in the summer. The work also showed that the high electron

densities of the so-called "winter anomaly" of the F-region represent, in fact,

the normal situation, the summer being the anomalous season because of its abnormally low electron content. Chemical Release in the Ionosphere. The Bureau participates in a

series of experiments sponsored by the Air Force Cambridge Research Laboratories involving the release in the F- and F-regions of the ionosphere of

substances having high chemical reactivity and observing reactions following. In a recent series of such experiments, NBS ionosondes detected the

presence of "sporadic-F" ionization at the exact level of a strong shear in

the neutral wind profile, revealed by viewing a luminous rocket trail, thus

confirming a recently developed theory accounting for the formation of

152
sporadic-^. In another experiment, a rocket released 20 kg of sulfur hexafluoride in the daytime F-region, producing a large region of reduced elec- tron density through the attachment of electrons to the sulfur hexafluoride

molecules. Ionosondes detected this electron "hole" in the ionosphere and

showed its growth and ultimate decay over a 30-min period.

Electron Density Measurements in the Ionosphere. New developments, jointly sponsored by the Bureau and the National Aeronautics and

Space Administration, in radio soundings of the ionosphere and in precision

calculation of electron distributions from these soundings are providing

greatly improved detail concerning the structure of the lower F-region. By

extending downwards the radiofrequency range of the sounding equipments

at many of its associated ionosphere observatories, the Bureau hopes soon

to be in a position to prepare a worldwide survey of the occurrence of nighttime ^-region ionization. The measurements also should permit improved

identification of the main levels of absorption of solar energy in the atmosphere and will assist study of the influence of the ionosphere on long-distance

radio services.

TROPOSPHERE AND SPACE TELECOMMUNICATIONS

Most efficient use of the radiofrequency spectrum is the aim of the

Bureau's program in tropospheric propagation and radio noise. Attaining

this objective requires a basic understanding of radio wave propagation,

noise, and interference. To this end, theoretical and semiempirical prediction methods are developed and compared with statistical samples of

data on radio wave propagation and radio noise. As has been the custom,

a major part of the effort was carried out in support of the Consultative

Committee on International Radio. Several members of the Central Radio

Propagation Laboratory staff attended the Xth Plenary Assembly of the

CCIR from January 15 to February 15, 1963 in Geneva, Switzerland, in

preparation for the International Telecommunications Union Extraordinary

Administrative Conference on Space Radiocommunication, including Radio

Astronomy, held in Geneva in September 1963-

Reports to the CCIR. A comprehensive report on methods for predicting radio transmission loss at frequencies above 40 Mc/s was presented

to the CCIR, and a summary of this report was adopted. These methods

were subsequently used to prepare a set of propagation curves for the International Frequency Registration Board to use in its planning for African

television broadcasting. A short summary of engineering curves for predicting the absorption of microwaves by oxygen, water vapor, and rain, and

for predicting sky noise temperatures was also adopted.

An international working party was set up, under the chairmanship of a CRPL staff member, to examine the theory of figures of merit for a receiving system limited by receiver noise, external noise, or by other un- wanted signals and its application to optimum use of the radiofrequency

spectrum.

153
Prediction Methods. A comprehensive report on methods of trans- mission loss prediction, including a description of the newest methods of

calculating service prohahility. is being prepared. It includes a discussion

of theory and comparisons with results obtained by a triple numerical

integration. The integral made possible a more adequate investigation of

the problem caused by undesired scattering of conventional terrestrial

radio signals along the beam of a satellite communication or radio astronomy

antenna. Use of the integral also permitted existing predictions of path

antenna gain to be updated and generalized.

Electromagnetic Theory. Computer programs were develoned for

solving diffraction problems by means of the general Fresnel-Kirchhoff theory

for diffraction over a single, prefectly absorbing knife-edge, with ground

reflected components on either or both sides of the knife-edse. Another

computer program, develoned for a special case of the general formulation,

permits calculation of diffraction over two knife-edges: excellent agreement was obtained with laboratory data at 20 Gc/s.

Prediction of limitations on radio tracking of rocket launch trajectories

imposed by the atmosphere was made in further studv of the theory of

variance spectra associated with radio phase variations on line-of-sight

paths.

A study being carried out for the Signal Corns, in connection with the

communication problems 'of an Army in the field, compares the path-topath variability of transmission loss observed over irregular terrain with

a statistical model of terrain profiles. This model depends on the variance

spectra of deviations of such a profile from its average slope.

Point-to-Point Moon Communication. An atlas of ground proximity losses and impedances for various antennas was prepared as a guide for

planning communications between exploring parties and base installations on the surface of the moon. This makes it possible to determine receiver

characteristics required to overcome noise and transmission loss at various

distances. Propagation over a sphere having layered ground constants was extensively investigated in this connection.

Radio Meteorology. The direction of research in tropospheric radio

propagation focused more attention on the physics of the medium. The

effects of the atmosphere on communication frequencies from VHF to the

optical range—with emphasis on refraction, scintillation, and scattering

necessitated new basic programs in radio meteorology. The turbulent characteristics of the radio refractive index at microwave frequencies were shown to be chiefly those due to the water vapor of the atmosphere, thus uniting the

efforts of the radio scientists and the meteorologist. It was found that in- formation on water vapor turbulence can be roughly correlated with refractive index turbulence. The ease and accuracy of measuring refractive index

variations by radio means can be useful in studying water-vapor variations.

Techniques of studying the vertical structure of the atmosphere from

ground-based radio detectors are being fully investigated. Experiments

include probing the vertical structure of the refractive index by high-powered

154
radar and passive detection of water vapor from the thermal noise emitted

by the water vapor molecule. Passive detection of oxygen, also, would provide a convenient probe of the vertical temperature distribution.

Efficient Television Assignments. The amount of the radio spectrum

allocated to television broadcasting is quite large, amounting to about one

half of the spectrum below 1000 Mc/s. A recent CRPL study of methods

for making television assignments indicates the feasibility of reducing the

spacing between cochannel and adjacent-channel stations. Interference

effects would be minimized by using precise-carrier offset, alternate trans- mission polarizations, and receiving antenna directivity.

A sample VHF assignment plan for the United States using reduced spacing

indicates the possibility of a twofold increase in the per-channel coverage.

The most significant increases would be in the number of areas served by

several channels—two or more, three or more, and so on. Conferences were held between the Bureau and the Federal Communications Commission to explore various problems associated with implementation

of the plan, as well as possible courses of action which might be undertaken.

VHF Air-Ground Propagation Tests. Continuous measurements of

propagation characteristics for long air-ground paths both within and beyond the line-of-sight were continued during the second transmission year

of the Midwest Program on Airborne Television Instruction (MPATI).

These measurements provide a unique set of data in that the transmissions

emanate from an airplane at an elevation of 23,000 ft in the 800 to 900 Mc/

range.

Although the current MPATI service is for educational television broadcasting, it made possible a great deal of worthwhile information on transHigh-flying UHF television station broadcasting educational programs over

Indiana. Signals are studied by the Bureau to examine variations in trans- mission loss both within and beyond the radio horizon. (See p. 155.

)

155
mission loss variation which has application to many other services employing high terminals, including space-earth propagation.

Refractive Effects in Microwave Distance and Position Measurement Systems. Precision distance and angular position measurements

made with systems involving microwave propagation (such as those used

in geodetic survey work and in tracking missiles and space vehicles) are

subject to errors caused by random fluctuations in the refractive index of the

turbulent troposphere. A series of experiments designed to study these

distance and angular position errors in long-baseline tracking systems,

such as the Air Force Mistram system, was completed. The results include an analysis of the correlation of atmospheric errors on adjacent radio paths,

as well as the correlation of distance errors on a single radio path with

atmospheric refractive index data.

An experimental study was made of the atmosphere-induced variations

in the amplitude and phase of arrival of microwave signals sent over the same low-level line-of-sight path, but at slightly different frequencies. The

data analysis included the correlation of phase variations at two frequencies

as a function of fluctuation (power spectral) frequency. This work was

prompted by the high amplitude and phase stability required in the operation

of ground-to-ground calibration and synchronization links in some longbaseline tracking systems. A program was initiated to systematically study

the dependence of angular position errors on antenna aperture size and on

baseline length and orientation. Experiments are also being conducted

for the Army Engineers to study the feasibility of using microwaves in a

portable azimuth-measuring system.

Surface-Satellite Communication Interference. In the event that

space telecommunications services share frequencies with surface systems,

such as point-to-point microwave systems, isolation between terminals of the

systems will rely on geographic separation and antenna discrimination. It

is possible to make fairly accurate predictions of the service fields of signals

propagated through the troposphere, but little is known about the kinds of

efficient propagation that occur infrequently and cause serious interference.

One source of such interference in the 1 to 10 Gc/s range is expected to be

elevated concentration of rain and hail associated with thunderstorms.

An experimental program was undertaken to determine the effects upon

space communication system performance of forward scatter interference

from thunderstorm cells. Measurements were made at 4.8 and 9.1 Gc/s

over a 180-km-wide area of cells and squall lines containing varying amounts

of rain, hail, and thunderstorm activity. Signal paths having transmission

loss values comparable to those of great circle scatter communications were

observed for cells which were off a great circle route. Forward scatter signals were correlated with weather radar data to develop a prediction basis. These

measurements will be continued to obtain a reliable basis for appraisals of

interference.

Bandwidth of the Tropospheric Propagation Medium. The

amount of information that can be sent over a tropospheric radio path is

156
Table Mesa site near Boulder, Colo., showing antennas used in studies of the

bandwidth limitation of the tropospheric medium. The data developed will aid in evaluating comunication systems. (See p. 156.)

limited by the fading characteristics of the medium itself. The degree to which this limitation is imposed is dependent on may parameters, including

distance and type of modulation.

An experimental program was initiated to investigate the relationship

between the bandwidth of tropospheric scatter paths and the performance of

multichannel, angle-modulated radio transmissions over them. Bandwidth

is determined by measuring the coherence of discretely frequency-separated

carriers and the performance of multichannel systems in terms of distortion

present in the received signal. Previous work indicated that the customary

criterion for coherent bandwidth results in a path-bandwidth determination

somewhat less than the bandwidth used in successfully operating tropospheric

scatter systems. The present program is designed to explore new criteria

for coherent bandwidth which will correctly indicate system performance.

Frequency dependence is also being considered in the frequency range from

400 Mc/s to 5 Gc/s.

A suitable prediction formula for the performance of tropospheric scatter radio systems is a longstanding need; it is estimated that progess in this area lags transmission loss prediction methods and equipment developments

by several years. The path-bandwidth studies in progress will result in the

determination of a suitable method for predicting the performance of tro- pospheric scatter radio systems in terms of voice channel signal-to-noise ratios or telegraph error rates. The limitations due to distortion of multipath

propagation through the troposphere will be taken into account. Thus, the

present program will result in a substantial contribution to the state of the

art of tropospheric scatter systems.

157

*v—H|
Radio Noise Predictions. Atmospheric radio noise, originating from

worldwide thunderstorm activity and propagated via the ionosphere, represents the irreducible interference level with which a signal must compete

at a receiver in the high-frequency portion of the spectrum. Accurate

prediction of this noise on a worldwide basis is vitally important to users

of this portion of the spectrum.

Improved predictions are now being provided by means of corrections

to previously prepared CCIR Worldwide Prediction Charts. These corrections were prepared by evaluating data collected in the CRPL worldwide

noise-recording network, using several unique electronic computer programs.

Besides improving the prediction of noise power, these corrections make

possible for the first time predictions of such additional parameters as

deviation of the envelope voltage from that producing the average power.

Estimates of the reliability of predictions are presented in the form of

standard deviations for each parameter.

NBS studies of variability of radio noise over large water areas are carried out

aboard the National Science Foundation's Floating Antarctic Research Station,

the USNS Eltanin. (See p. 158.)

Floating Noise Recordings. For the first time, quantitative, objective

radio noise measurements were made from a floating radio noise station.

These measurements began with the installation of an ARN-2 radio noise

recorder aboard the National Science Foundation's Floating Antarctic Research Station, the USNS Eltanin. Radio noise data were gathered at eight

frequencies between 13 kc/s and 20 Mc/s during the cruises, lasting up to 80 days, made in the last year. The recordings were made primarily from

about 40° south latitude to the edge of the Antarctic ice pack, and from

about 50° west longitude to about 85° west longitude. From the preliminary

analysis of these data, it appears that very interesting information on the

variability of the radio noise over large water areas will be obtained.

158
Automatic Data Analysis Facility. The service provided by its au- tomatic data analysis facility is an important phase of CRPL activities. The data analysis instrumentation center was established to process auto- matically data recorded on a magnetic tape medium. Playback-to-recorded

speed ratios as high as 100 : 1 can be selected to attain extremely rapid data

handling.

The data analysis facility provides, in addition to general data trans- lation to put data into a format for use on large scale digital computers, sev- eral types of complete analyses by means of special purpose analog and

digital systems. These systems operate on the data read directly from

the magnetic tape in either direct or the frequency modulation mode.

Typical analyses include those of power spectral density, multichannel

distribution for amplitude and fading characteristics, continuous auto- and

cross-correlation as a function of fixed time lag and averaging time, dynamic

autocorrelation yielding an automatic plot of the correlogram as a function

of time lag, and other general analog and digital techniques for measuring

signal parameters.

Included in this facility also are special instrumentation systems for auto- matic time-code searching and control of tape, nonlinear function generation,

and other automatic data control and conditioning functions.

Instrumentation research associated with the facility has proved to be of

great benefit to many outside agencies, as well as to the Bureau.

RADIO SYSTEMS

The Bureau's radio systems program provides technical information on radio propagation factors affecting 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, groundwave, 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 engineering practices, allocation and use of radiofrequencies, and evaluation

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 communication operation and regulation.

Studies of modulation, antenna design, information theory, and coding

are directed toward improvement of the reliability of systems and to the

efficient utilization of the radiofrequency spectrum. Consulting and advisory

work is done in accordance with the needs of other government, commercial,

and scientific agencies.

High-Frequency Ionospheric Radar Research. Radar observations

of long distance, high-frequency, backscattered signals are being made to provide needed information about the size, velocity, and direction of motion

of ionospheric irregularities and their relationship to HF radar and communication problems. One observing technique, using a new 12 to 25

159
Mc/s high-resolution azimuthal scanning antenna, permits surveillance of a large area of the ionosphere (of the order of 10r

' sq km projected) with

a resolution of about 50 km. Analog signals of the hackscatter energy

at fixed frequencies are recorded on magnetic tape and then digitized for

input to the 7090 computer for analysis. The computer program averages

the hackscatter amplitude returned from identified cellular units of range

and azimuth and subsequently plots it. Variations of the amplitude contours

with time provide information about the motions of ionospheric irregularities. An elevation-scanning array operable over the same frequency range

has been constructed for use in conjunction with the azimuthal scanning

array.

A second technique used in making hackscatter observations is that of

sweep frequency measurements with either fixed antennas or a rotating log

periodic antenna for transmitting and receiving. Ionospheric irregularities are evidenced on the hackscatter record as intensification in the signal

amplitude over a range of frequencies which changes with time, the amplitude being related to the speed of motion of a focusing irregularity in the

ionosphere. An investigation was made, on a limited data sample, into

the frequency dependence of the apparent speeds of the irregularities as a function of the observing frequency. This dependence was found to be

37.5 km/hr/Mc/s, with lower speeds being found for the higher observing

frequencies. Mean speeds of the irregularities ranged from 900 km/hr at 12.5 Mc/s to 570 km/hr at 22.5 Mc/s.

Preliminary analysis of the spectrum and amplitude distribution of fading HF hackscatter signals was begun. The fading spectrum at a given

Erection of an antenna at the NBS Erie (Colo.) field site for radar studies of

ionospheric irregularities. (Seep. 159.)

160
range contains components of several cycles per second down to a few cycles

per hour. The low-frequency components are related directly to the passage

of irregularities through the range of observation. Thus the low-frequency

components at one range would correlate with those at another range at a

different time. An estimate of the velocity of irregularities should be obtainable from this information.

Continuous-wave transmissions of high phase stability at 2.10 Mc/s and

4.055 Mc/s were made on a near-vertical incidence path. Phase-path and

group-path data on these transmissions were obtained to ascertain the natural

variations imposed upon such signals due to variation of ionization in the

ionosphere and motions of irregularities through it. Changes in the phase

path of the radio wave are measured by comparing the phase of the wave

reflected from the ionosphere with that of the ground wave direct from the

transmitter. Recording equipment capable of indicating rapid phase change

occurring in time intervals less than a millisecond has shown that Doppler

shifts up to 600 c/s occur frequently and last for a few milliseconds. Such

Doppler shifts were found to occur more frequently at night and are particularly frequent during spread-/" conditions. Some of these Doppler shifts are very likely the result of signal reflection from meteor trails. Solar Flares. Phase-path observations made at times of solar flares have shown that solar flares of optical importance 1" usually provide sufficient

additional ionization below the reflecting point in the /-region to be detected

by phase changes in the 4.055 Mc/s transmission. Only occasionally does

the 2.10 Mc/s transmission, which is reflected from the /-region, show identifiable phase changes due to the small flares. The rate of phase-path change

for 58 solar flares, measured at 4.055 Mc/s at the time of onset of the

radio effects, has shown a median value of about 10 wavelengths per minute.

For only 10 percent of the flares observed did the onset phase path change

exceed 24 wavelengths per minute. The median duration of phase change

resulting from these flares was five minutes. Neither the phase-path rate- of-change nor the duration of the radio disturbance seems to be directly

associated with the flare importance.

Modulation Research. Theoretical and experimental studies of modulation, detection, and coding techniques, the characteristics of time-varying

propagation media, and their relationships were continued. Experimental

studies were made to test the thesis that the limitations imposed on FM trans- mission by the correlation bandwidth of the medium pertain to the maximum

modulating frequency, rather than to the deviation or maximum excursions

of radiofrequency. FM communication tests over a 1295-km long, 50 Mc/s

ionospheric-scatter circuit were conducted to determine the quality and

distortion suffered by signals using various modulation indexes corresponding to deviations from less than to greater than the correlation bandwidth

of the medium. Using a number of listeners, hearing tests were made of the

recorded voice signals to determine subjectively the quality of the signals for

the various modulation indexes. It was found that the quality improved

with increasing modulation index and with the frequency deviation well

161
beyond the 5-to-7 kc/s bandwidth of the medium, as earlier determined by

fading correlation measurements.

Theoretical studies of error-detecting and -correcting codes continued

with an analysis of a combinatorial problem pertinent to the theory of

runs. The solution obtained applies to the decoding of cyclic codes and

leads to a particular simply instrumented error-detecting and -correcting

decoder. The Department of Electrical Engineering at the University of

Colorado completed a study of short error-detecting codes for the Bureau.

Theoretical studies were made at the Bureau of the probability of binary

errors as a function of average signal-to-noise ratio for a number of modulation techniques subjected to Gaussian noise and a gamma fading model.

This model is more comprehensive than the commonly-used Rayleigh model

and allows for a variety of short-term fading statistics. Studies were also

made of the probability of binary errors as a function of average signalto-noise ratio for a signal subjected to atmospheric noise and Rayleigh

fading. Although atmospheric noise has a considerably different amplitude

distribution than Gaussian noise, the study showed the element error probability to be little different than for Gaussian noise when Rayleigh signal

fading occurs. Work is being continued to consider other fading models

and a variety of modulation-detection techniques.

Digital Errors. Five flexible digital logic equipments were installed

they can be programmed by patch panels to provide a variety of instrumentation quickly and easily for future digital communication experiments.

An experimental program was started, using this equipment, to obtain the

distribution of digital errors in a high-frequency communication link using

frequency-shift keying. Simultaneous oblique soundings of the ionosphere

over the same path will be used to relate the error distributions to the propagation conditions. The purpose of the planned experiments is to obtain the

information necessary to design more efficient digital error-detecting and

-correcting codes for such links.

Testing Facsimile Equipment. The performance of four types of

facsimile equipments was measured for the Air Force. A test chart was

designed to present recording density, resolution, and legibility. Mechanical and electrical performance of the equipments was measured in back-toback operation and in long-line operation.

Recording Atmospheric Noise. Evaluation and intercomparison of

the performance of radio systems in the presence of atmospheric noise

is difficult because the characteristics of the noise are variable in time,

making desired or repeatable noise conditions nearly impossible to obtain.

A method of overcoming this difficulty is to have a library of atmospheric

noise recordings, exhibiting a variety of characteristics that can be used in

performance tests. However, conventional tape recording of atmospheric

noise is impractical because of the extremely large dynamic range of the

noise. For this reason a wide-dynamic-range tape-recording technique for

atmospheric noise was developed; it extends the range of a conventional

recorder by dividing the noise signal into different amplitude ranges for

162
recording on separate tape tracks. A dynamic range of 90 db was obtained,

using two tracks, over each half-octave bandwidth between 1 kc/s and 25

kc/s and, with frequency conversion, over any 10 kc/s band between 25

kc/s and 500 kc/s. A system obtaining greater dynamic range and bandwidth could probably be developed for more tracks with the use of proper

shielding precautions.

Multipath Microwave Transmission. The development of an ex- perimental microwave system was completed for propagation studies in the

coming year to determine the bandwidth limitations on multipath propagation of 10-Gc/s signals at several elevation angles. The tests will be con- ducted by transmitting pulses of one nanosecond duration from a mountaintop to several lower-elevation receiving sites for resolution of path length

differentials of one foot or more by use of the short pulses. The objective of

the study is to determine if sufficient tropospheric multipath propagation can occur over nonhorizontal paths to limit the information rate that can

be transmitted between satellites and earth. Ionospheric effects are expected

to be negligible at frequencies above 10 Gc/s. Antenna Measurements and Research. The principles of electronic

antenna scanning developed at the Bureau in 1959-60 were extended to scanning in the elevation plane and applied in the HF ionospheric radar

program. A tower 152 meters high was erected on Table Mesa. Ten logperiodic dipole antennas were arrayed along its vertical length at 16-meter

intervals, starting at 8 meters above ground. By an application of antenna

aperture synthesis it was found possible to improve the aperture efficiency over that attained using uniform amplitude. The improved "illumination"

is accompanied by current amplitudes varying sinusoidally with height.

The period of the sinusoidal variation determines the angle of departure.

Such current distribution results in an enhancement of gain by approximately

3 decibels and a reduction of the main beamwidth by a factor of 2. The

above comparison is with the same antenna having uniform amplitude il- lumination and phase advanced (or retarded) uniformly by an amount

proportional to height.

The antenna was erected next to the horizontal array of 25 log-periodic

antennas electronically scanned in azimuth, and is intended to supplement it. Both operate in the band of 12 to 25 Mc/s and have been designed for HF

ionospheric propagation studies.

Computer Program for Radiation Patterns. A computer program

was prepared to determine radiation patterns of curtain arrays for the

Voice of America. The program was made as general as possible, allowing

for such variations as in the number of bays and elements stacked one above

the other. It presents both the horizontally and vertically polarized fields

as well as the composite power pattern.

Progress was made in applying antenna aperture synthesis to the analysis

of complex electromagnetic fields. A computer program was designed to evaluate the components of plane wave fields from measured field amplitude

and phase distributions. Strength, polarization, phase, and direction are

163
Azimuthal and elevation electronically-scanned arrays at the NBS Table Mesa

(Colo.) field site are used in high-frequency ionospheric propagation studies.

(See p. 163.)

obtained for each of the several component sources of the field. The program was tested, using simulated field measurements obtained from as- sumed components; the component values were accurately reproduced in

the test computation. Experimentally obtained data likewise were reduced

to original components closely approximating known values.

Frequency Utilization. Services for the computation of HF radio

path performance, with emphasis on the selection of optimum frequencies, were expanded through the development of faster and more comprehensive

computer programs. Research into improved methods of predicting HF radio

system performance, using ionospheric data, radio noise data, service requirements, and antenna and modulation information, paralleled the development

of computer programs.

164
Services using computers to predict HF radio system performance are divided between the routine prediction and special studies. Examples of

routine predictions are those for operation of the ground communication

complex of the NASA communication system and for monthly predictions

for the wire news services. Numerous special studies were devoted to problems such as the long-range planning of NASA and VOA facilities and

the Bureau's consideration of relocating standard frequency station WWV.

In connection with development of U.S. policy concerning frequency usage

within the United States, reports were prepared to summarize the technical

considerations in the selection of optimum frequencies for space communication systems and for HF communication systems.

Radio Navigation Research—Low-Frequency Loran. Through a unique program involving several agencies, extensive low-frequency ionospheric radio propagation data have been obtained at very nominal cost. This was done in a cooperative program cosponsored by the Bureau, the

Coast Guard, and the Advanced Research Projects Agency of the Department of Defense. Since the Loran-C radio navigation system uses ground- wave transmissions at LF (100 kc/s), several Loran-C stations were asked

to participate in obtaining propagation data. Existing standby equipment was slightly modified to make reciprocal measurements of the singly-reflected

ionospheric signal over two paths. The paths, a high-latitude path in the

Aleutian Islands and a low-latitude one in the mid-Pacific, were chosen be- cause of special interest in these regions during high-altitude nuclear tests. Preliminary analysis of the year's data obtained from the Loran-C operation over* the high-latitude path indicates many interesting and unusual

phenomena. Phase and amplitude readings taken every 15 minutes at each

end of a reciprocal path have been analyzed and the known phase and amplitude of the ground-wave vector removed at each data point to obtain the

uncontaminated, singly-reflected, ionospherically-propagated primary signal.

For departure from mean values there was very poor correlation between

phase and amplitude changes at all times; the correlation was calculated to be less than 0.2 for the entire year. The correlation between phase changes

observed at the two ends of the reciprocal path was approximately 0.6 for a

year's data. In a separate study involving fast phase changes occurring at the two

ends of the path, only one out of three changes was seen simultaneously at both ends of the path. The correlation coefficients for the amplitude fluctuations on the reciprocal path range from 0.6 to 0.7 during the day to less than

0.1 during the night.

The standard deviations of both the phase and the amplitude data were

higher during the winter than during the summer, and higher during the

night than during the day for both winter and summer. In general, the

amplitude fluctuations demonstrate poorer reciprocity than do the phase

fluctuations, and both demonstrate poorer reciprocity at night than during

the day. Another interesting observation is that both the phase and amplitude fluctuations exhibit nonreciprocity at times.

165
Applied Electromagnetic Theory at Frequencies Below 300 kc/s.

A theoretical problem of propagating an electromagnetic pulse via composite

ground and ionospheric waves was solved for propagation in the waveguide

between the ionosphere and the ground, for long wavelengths (over 1000

m). This required the construction of suitable transfer functions for both

the ground wave and the ionospheric wave. The concept of continuous

stratification of the lower ionosphere and arbitrary, constant magnetic

field was introduced into the solution, so that the form of the lower boundary of the ionosphere with respect to altitude could be taken into account

as a profile of electron density-altitude, N(h), and collision frequencyaltitude, v(h). Collision frequencies proportional to the thermal energy

of the gas were introduced into the analysis with the aid of a complex

collision frequency parameter in the Langevin equation of motion of an

electron gas. This parameter was found to be frequency-dependent and

characterized by three frequencies: to, <o±<on where /=oj/2tt is the frequency

under consideration and Ih =wh/1tt is the gyrofrequency of the electrons.

The residue and zonal harmonic methods for the computation of LF,

VLF, and ELF radio fields were extended to take account of an anisotropic

ionosphere. These methods were introduced as a rigorous supplement to the geometric-optical theory.

Thus, the exact solution to the problem of propagation of terrestrial

radio waves around a sphere having a concentric ionosphere can be represented theoretically as a notoriously slowly converging series of zonal harmonics. Nonetheless, the advent of large-scale computers makes this classical, apparently intractable, solution quite practical at frequencies less than

30 kc/s. The rigorous residue methods which were also developed in considerable detail on the large-scale computer offer a highly convergent representation of the exact solution. It is interesting to note, however, that the

zonal harmonics method is still competitive at frequencies less than 30 kc/s,

since the search for residues in complex Riemann surfaces is difficult to program reliably for a computer over a wide frequency range. Furthermore,

the zonal harmonics were found to be an independent numerical check in

practice, since this method gives the same answers, by definition, as obtained

using the Cauchy residue theorem. A detailed study was made of all approximations employed to introduce the effects of anisotropy of the ionosphere

into the theory of propagation; computer programs were devised to calculate

the field under a variety of circumstances.

An extensive program to interpret the Loran-C radio navigation-timing

pulse measurements with the aid of the theory of propagation described was begun and methods studied for testing various profiles or models of

the lower ionosphere under the variety of specific experimental conditions

offered by Loran-C. Models were proposed for various times of the day

and various latitudes. In general a considerable knowledge of the lower

ionosphere was gained by application of the theory to experiment. Further,

it was found that such combined effort prompted further research to improve the theory of propagation166
Optical Communications Studies. A limited study program on laser

systems was initiated to investigate the propagation of coherent optical

(infrared and submillimeter wave) radiation through the atmosphere to provide information on short-term fading and angular scintillation for

communication channel characterization. A helium-neon cw laser will be

used initially for a radiation source and transmission from Pikes Peak to Boulder is now being carried on. Microwave and meteorological meas- urements for this path will be obtained and the laser data will be analyzed

and correlated with the measurements.

UPPER ATMOSPHERE AND SPACE PHYSICS

Knowledge of the atmospheric medium is a prerequisite to the understanding of the propagation of radio waves through this medium. This

knowledge is also essential in a host of applications in addition to radio communication. The program of upper atmosphere studies is conducted using

three experimental approaches in addition to theoretical studies. The ex- perimental approaches are (1) ground-based geophysical observations, (2)

satellite observations, and (3) laboratory experiments simulating atmosphere processes.

Jicamarca Radar Observatory. At the Jicamarca Radar Observatory, located on the magnetic equator near Lima, Peru, studies are being

made of various features of the equatorial ionosphere with a powerful radar

at 50 Mc/s. Its basic function is to study the distribution of electron

density for heights to 10,000 km or more above the earth's surface by means

of the incoherent scatter technique. Other parameters of the ionosphere,

such as electron and ion temperatures, are also being measured.

It was recently discovered at Jicamarca that ion gyrations, which were

expected to affect the incoherent scatter signal, were not detectable. This

result has now been explained on theoretical grounds. Thus, the use of the

Jicamarca radar as a ground-based mass-spectrometer will now depend upon

other characteristics of the incoherent scatter spectrum.

The Jicamarca radar has been operating at full capability for incoherent

scatter studies since December 1962. Since that time incoherent scatter observations have been limited to tests aimed at confirming theoretical

predictions of the influence of the ion and electron temperatures. This has

been necessary, inasmuch as some difficulty is experienced in measuring elec- tron density accurately in regions where more than one ion species is present

in significant concentration. The preliminary tests are nearing completion

and it is hoped that semiroutine measurements of electron density versus

height, as well as ion and electron temperatures versus height, will soon begin.

The extremely high radar sensitivity available at Jicamarca enabled the

detection of radar echoes from Venus when the planet was observable from

Lima during the first week of December 1962. Both short (l/2000th of

a second) and long (3/1000th of a second) pulses were transmitted.

Echoes from the long pulses often were at a level four times the background

noise. Practically no pulse-spreading was observed, indicating that the

714-691 0—64 12 167
surface of Venus is considerably smoother than that of the moon. From observations of the synchrotron radio noise emitted by trapped

electrons resulting from the July 9, 1962 nuclear explosion, a fairly accurate

description of the energy distribution of the electrons was made. The decay

rate of the artificial radiation belt was observed and is the subject of con- tinuing study.

The equatorial electrojet is one of the equatorial phenomena being studied

at Jicamarca. This is a strong daytime current stream flowing in the

ionosphere at a height 100 km above the magnetic equator. Radar echoes

obtained from irregularities in the electrojet led to the theoretical explanation that the irregularities are produced by a "two-stream" plasma instability

in the electrojet current. The theoretical and experimental results are completely consistent in the electrojet case, and the implication is that the same interpretation can account for similar irregularities observable in the aurora. The results obtained at Jicamarca form one of the first instances

in which theoretical predictions regarding plasma irregularities were con- firmed experimentally with good precision.

The 22-acre radar antenna of the Jicamarca Radar Observatory near Lima, Peru, was recently used for studies of the planet Venus and the equatorial electrojet

in addition to its regular functions in measuring parameters of the ionosphere.

(Seep. 167.)

168
r- -

Digital correlator and

control system for the

Jicamarca Radar Observatory near Lima,

Peru, provides for more efficient use of

the radar and analyses

of the received signals.

(Seep. 169.)

Digital Control and Correlation System for the Jicamarca Radar

Observatory. The Jicamarca radar is used to measure the characteristics

of the ionization in the ionosphere and exosphere. Since the reflected radar

signals are often very weak, special detection methods must be used to extract the desired signals from the noise background. A new device for doing this was recently installed at the radar site. This device, called a digital correlator, is actually an interconnected set of timing and signal-processing

modules which forms a complete control and detection system for the radar.

Individual modules of the system include voltage-to-digital converters, a magnetic-core buffer, a multiplier, a pulse-height analyzer modified to serve as a multichannel accumulator, and a variety of pulse-generating and

switching units. The sequence of events occurring in an experiment is determined by a module called a programmed controller, which controls the

sequence in which other modules perform such functions as radar pulsing,

observing the reflected radar signals, storing the received signals, and computing correlation coefficients.

The entire system of digital correlator modules and the radar is electrically

interconnected through a removable plugboard. An experiment can be set up in a relatively short time by placing a plugboard, which has been prewired to perform the functions of a particular experiment, in the plugboard receiver. By this means, within a few minutes after an unusual

169
ionospheric or exospheric phenomenon occurs, an experiment designed to observe that phenomenon can be in operation or an existing experiment

modified to make special observations. The result of having the correlator

in use is that better, more rapid, and more numerous observations and ex- periments are made possible.

Studies at Magnetically Conjugate Points. Following the successful

pilot conjugate point experiment conducted during the Antarctic summer

of 1961-62, a more ambitious operation was organized, supported in part

by the National Science Foundation, to run through 1963 and extend into

the IQSY.

The concept of conjugate-point studies is that observations made at opposite ends of a given line of the geomagnetic field permit the investigation

of geophysical phenomena which are propagated along the field. The pilot

experiment used just one pair of stations and therefore gathered data on phenomena occurring on just one geomagnetic field-line (L =4). The new

program includes three conjugate pairs: Antarctic stations South Pole

(Z,— 13), Byrd (L = 7y2 ), and Eights (L =4>) are paired with corresponding

Canadian stations at Frobisher Bay, Great Whale River, and Baie St. Paul.

The data will be obtained from latitudes greater than, equal to, and less than

that of the auroral zone maximum.

A variety of instruments, including the riometer, VLF receiver, micropulsation equipment, and magnetometer, is in use at the conjugate stations.

The wealth of new data being obtained will be applied to test and extend the

preliminary results obtained previously. It is already apparent that many

of the absorption events measured with riometers are of different intensity

in the two hemispheres, and there are indications that significant time delays

exist between some conjugate events. Although many events correlate very

well, some are observed in only one hemisphere. When full data become

available from the Antarctic, a more complete analysis of the occurrence,

structure, scale, and movement of absorption events will be possible. Valuable data are being gathered about VLF emissions, both discrete and continuous. The wide range of techniques now in use will make for interesting

interdisciplinary comparisons.

Continuous Observations of VLF Emissions. VLF emissions have

been observed continuously since May 1961 and recorded continuously at several locations. Because of the low time resolution of the instrument it was possible for the first time to pick up VLF pulsations having periods of

20 to 300 seconds. These periods are in the same time range as micropulsations and some X-ray events; the possible connection between these two

phenomena and VLF events is being studied.

VLF Emissions and Whistlers at Conjugate Points. The Bureau

started its program of systematic observations at magnetically conjugate

points in 1961. Whistlers echoing between the hemispheres were observed

as early as 1956, but only a few observations of VLF emissions at conjugate

points have been reported. The results from the conjugate point stations

reveal several patterns.

170
VLF emission events which last for several minutes to several hours are seen simultaneously at conjugate points. When these same events are ex- amined in detail, it is found that the separate discrete emissions which make

up the total event alternate between the hemispheres. This alternance may

be due to echoing of the VLF wave, or re-emission of the wave. Electron Densities in the Lower Ionosphere. The Z)-region and its physical and chemical properties are of interest from the practical viewpoint

because of the disruptive effects the Z)-region can have on long-range radio

transmissions. The Z)-region is of great scientific interest also because it is the region where energetic particles of extraterrestrial origin interact with

the atmosphere. However, the D-region is at a particularly difficult height

(40 to 90 km) to study directly because the atmospheric density is too great

for satellites to orbit in it and too small to support high-altitude balloons.

Therefore it must be studied by rockets (which remain in the region only

minutes) or by ground-based techniques. The latter have the advantage of

continuous operation.

An observational program was conducted to measure the auroral-zone

absorption of cosmic radio noise as a function of frequency. By means

of refined experimental techniques and the development of a special computer program, it is possible to interpret these data in terms of the height

profile of electron density in the Z)-region. Such profiles have been deduced

for polar-cap absorption events and for some types of auroral events. The

analysis is continuing, and should provide valuable information about the

physical and chemical processes of the Z)-region.

This research is supported in part by the Advanced Research Projects

Agency.

Auroral Absorption. Radio propagation in the HF and lower VHF

bands at high latitudes is characterized by the frequent occurrence of strong

absorption which is often extremely variable in both time and space. This

absorption occurs in general association with aurora and magnetic disturb- ance and has become known as "auroral absorption" to distinguish it from

the less common "polar-cap absorption" associated with the influx of solar

cosmic rays. Auroral absorption displays several mysterious features; a

theoretical investigation of particle bombardment processes in the upper

atmosphere has been started, with the ultimate aim of explaining some of

these features. In particular, the role of high-temperature electrons in

producing some of the observed effects is being considered. When an

electron is freshly produced by ionization, its energy may be several hundred

electron-volts, corresponding to an extremely high effective "temperature."

This energy is eventually lost through collisions with atmospheric atoms and

molecules, but during this process the collision frequency is very high so

that the energetic component of the electrons may contribute appreciably

to radio-wave absorption. A further raising of electron temperature, and

hence collision frequency, may be due to electric fields in the ionosphere;

this point is being investigated.

171
Absolute Calibration of Airglow Photometers. Two problems arise

in connection with the calibration of night airglow photometers: the light

level is near the low end of eye visibility, and the large field of view

customarily used makes it difficult to use point sources of light.

The intercalibration of photometers on a national and international basis

is of particular importance. It is estimated that the spread of uncertainty

among the calibrations of the 28 airglow stations participating in the IGY

is probably contained within ±20 percent. A spread of such magnitude

ruled out the possibility of making detailed studies and interpretations

in a synoptic sense- The Fritz Peak Observatory set up a calibration laboratory in preparation

for the IQSY. The primary standard is a blackbody which illuminates a magnesium oxide screen. Secondary portable standards have been developed, using a mixture of two phosphorescent materials in which C14 has

been embedded. The spectral emission covers the range from the N2 + band

at 3914 A to the red oxygen line at 6300 A. Intercalibration between the

Fritz Peak standards and those of other airglow observers will be encouraged

in the hope that a significant improvement will be achieved during the

IQSY.

Mid-Latitude Red Arcs. The occurrence of so-called mid-latitude red

arcs, well-defined bands of atomic oxygen 6300 A red line emission along

restricted geomagnetic latitudes between the auroral and equatorial zones, has been observed at various times in the past few years. A promising model

now developed attributes the red arc excitation mechanism to electric fields

present in the ionosphere. The detailed calculations agree with the observed

properties of the mid-latitude red arcs as well as with the accompanying

geophysical manifestations of red arc occurrence. These calculations utilize

techniques previously developed at the Bureau for computing electron energy

distribution functions of atmospheric gases in the presence of electric and

magnetic fields. This model is of great interest as it suggests a connection

between the red arc occurrence and the physics of the magnetosphere where

the electric field is probably generated, possibly by the solar wind impinging on the earth's magnetic boundary.

Studies of Ionospheric Irregularities. Irregularities in electron density of the ionosphere can be revealed by study of the periodic fading of

radio signals from artificial satellites and cosmic radio sources. An analysis

of irregularities that vary from 50 to 400 km in the horizontal direction

revealed that they occur mostly at night, show no seasonal variations, and

decrease in density with increasing magnetic activity. They also appear to be distributed throughout the ionosphere. Observations made simultaneously

at three stations in a line parallel to the satellite path enabled a vertical

cross-section of the ionospheric irregularities to be obtained. Such a profile

is like a "snapshot," because of the high velocity of the satellite. A satellite scheduled for launch during the latter half of 1963 is to carry an ionospheric beacon transmitter that will enable a new and more accurate

analysis technique to be used. The accuracy of spaced station observations

172
will be improved, in addition, by equipment being built to utilize a new

receiving technique combined with telemetry to a central station. The re- sulting vertical profiles should reveal the changes of size and shape of irregularities with relation to such factors as time of day and magnetic activity,

and perhaps serve as a basis for rejecting or accepting theories of their

origin. An ionospheric beacon transmitter has been designed and is being

procured for another satellite, which will have a highly eccentric orbit so

that the measurement of electron densities far above the ionosphere can be

attempted. All of this work is supported by the National Aeronautics and

Space Administration.

Such irregularities can also be studied by observation of the bending of

radio waves that pass through them. Cosmic radio sources are being observed to analyze this bending in a cooperative experiment using a large

radio telescope, at Clark Lake, Calif., built and maintained by General Dynamics/Astronautics. Because the apparent motion of cosmic sources is but a fraction of that of a satellite, the motion of the irregularities thernselves

is being studied by this technique.

The bending of radio waves caused by small-scale irregularities, 1 to 2 km

in the horizontal direction, produces what are called scintillations in radio

signals. Observations of satellite scintillations verified that the height and

intensity of small-scale irregularities increases to the north and that differ- ences in geographical distribution are related to sunspot activity. This

work was supported by the United States Air Force.

Theoretical Studies of the Outermost Atmosphere. Plasma thrown

out by the sun and impinging on the earth's magnetic field from time to time

produces magnetic disturbances ("magnetic storms"), precipitation of

energetic particles into the ionosphere, occurrence of auroras, and disturb- ance of ionospheric radio communication. The mechanisms relating these

phenomena to each other are, however, not yet fully understood. Theoretical calculations have been made of the interaction of such solar plasma

with the outer portions of the earth's magnetic field. These calculations

show that the boundary region between the plasma and the magnetic field

lies closer to the earth on the night side than was earlier presumed to be

the case, but is farther from the earth in the polar regions than had been

presumed. This latter conclusion is of particular significance in evaluating

mechanisms theorized for the solar plasma reaching and disturbing the

ionosphere. Calculations are continuing on the amount of magnetic field disturbance associated with variations in the solar plasma, and the con- sequent displacement of conjugate points, connected by a magnetic field

line on the earth's surface, which have special radio disturbance properties.

Recent satellite measurements greatly extended our knowledge of physical

conditions in the outermost reaches of the earth's magnetic field. They have

shown, in particular, that in the general direction of the sun the magnetic

boundary region is usually found at a distance of 40,000 to 64,000 km from

the earth's surface, and that the trapped particles of the outer Van Allen

belt often extend out as far as this boundary. The behavior of these outer173
most trapped particles is believed to be of considerable importance in con- nection with auroras and magnetic storms ; for this reason a theoretical investigation of their drift motions was carried out recently. It was shown

that particles which become trapped in the outermost part of the geomagnetic

field tend to be concentrated into a relatively narrow belt, because of the

distorted nature of the field, as they drift from the sunward side of the earth

to the dark sTde. Also, a magnetic storm should have the effect of con- centrating preexisting trapped particles into similar belts, which can

persist after the storm has ended. Narrow belts of trapped particles of this

type were observed by satellites during magnetic storms. Their existence

may have a direct bearing on the production of the long, narrow arcs of

luminosity often associated with the aurora. Cyclotron Resonance in Slightly Ionized Gases. A detailed analysis of the line shape and width of electron cyclotron resonance absorption has

been carried out. At cyclotron resonance, i.e., the gyration frequency of an

electron in a magnetic field, the cyclotron orbits in a weakly ionized gas are interrupted by electron-neutral collisions, thereby determining the absorption-line width and shape. Analysis of the width and shape is quite complicated for many real gases due to the velocity dependence of the electronneutral elastic collision cross section.

The problem has been solved for various analytical representations of the

velocity-dependent cross sections using various electron energy distribution

functions. The problem was also solved for argon and nitrogen, using

experimentally determined cross sections and a Maxwellian electron distribution. The extreme importance certain minor impurities could have on band shape was demonstrated theoretically.

Space Resolved Afterglows. Studies of the space resolved "afterglow" in a fast-flowing helium discharge system were carried out by means of

emission and absorption spectroscopy. The afterglow technique is being

developed because of its possible use in studying chemical and electronic

reactions where the reactants (and electrons) are thermalized at essentially

room temperature. In the helium case the afterglow shows a very high

molecular-to-atomic emission intensity ratio relative to an active discharge,

a phenomenon as yet not understood. The density of both singlet and triplet metastable helium atoms was found to increase somewhat in the helium

afterglow region. The diagnosis of the helium afterglow is being extended

and other systems are being investigated by the flowing afterglow technique.

Infrared Spectra of Charge Transfer Complexes. A comprehensive and novel theory of the infrared spectra of weak charge transfer complexes was developed. These complexes are formed by transfer of electrons

from donors to acceptors ; it was shown that the infrared absorption characteristic of such a complex must be due to variation in the charge transfer.

This variation is a consequence of molecular vibration. Two specific

mechanisms are proposed for the variation and selection rules derived. The

large amount of data available on aromatic-halogen complexes is well ex- plained by this theory. A solution was proposed to a longstanding ambigu174
ity concerning the geometry of benzene-halogen complexes. The geometry

is of great significance for the theoretical understanding of the quantum

mechanical molecular description of such compounds.

Infrared Spectroscopy of the Atmosphere. The Bureau's Consultant in Physics of the Atmosphere conducted a continuing study of the atmosphere by means of spectroscopic observations. In order to compute the

transmission of infrared radiation through the earth's atmosphere it is neces- sary to know the atmospheric spectrum in absolute detail Atmospheric trans- mission is primarily dependent on absorption and re-emission by water

vapor, carbon dioxide, and ozone. The computation of atmospheric trans- mission was accomplished by a computer, using as input data the positions,

experimentally known strengths, and half-widths of 4400 specific lines for

transmission through water vapor. The 3.5/a (2857 cm"1

) to 2.25/1 (4444

cm-1

) portion of the spectrum used falls within the nonvisible infrared

region.

The transmission of the atmosphere is computed from the line positions,

strengths, and half-widths, using Beer's Law and a Lorentz line-shape profile. The absorption is computed at any given frequency as the sum of the

wing absorption of all the lines and the profile structure of an individual

line if the frequency position is near a line center. These theoretical absorption spectra are then degraded, using a slit function, in order to compute

spectra which are comparable to observed spectra. Comparisons with

high-altitude spectra obtained from aircraft by the Canadians and by the

British give excellent agreement with every detail in the water vapor spectrum.

An atlas of computed spectra for the 2.7 p, water vapor transmission has

been prepared. The absorption lines due to water vapor in the 1.1-, 1.4-,

1.9-, and 6.3-/* bands are being compiled. The positions, strengths, and

half-widths of the C02 absorption lines are also under preparation. This

theoretical analysis is being conducted under the sponsorship of the Advanced Research Projects Agency. The results of the calculations will be

applied to atmospheric radiative transfer problems.

ELECTROMAGNETIC RESEARCH

A number of theoretical studies conducted by the Consultant on Radio

Wave Propagation fall loosely into the category of electromagnetic research.

Supported by the Bureau, the Air Force Cambridge Research Laboratories,

and the Department of Defense Advanced Research Projects Agency, these

seemingly unrelated studies used methods having much in common- Some

of the accomplishments in this area during Fiscal Year 1963 are described

below.

Resonant Characteristics of a Corrugated Sphere. The radiation

from a radial electric dipole on the surface of a corrugated sphere was

examined. It was shown that the power radiated in a given mode depends

critically on the surface reactance and the circumference of the sphere. In

fact, for certain values of these parameters, particular modes are strongly

excited and contain most of the power. Such a structure can be regarded

175
as an external resonator having resonant characteristics that are a function

of the refractive index of the surrounding medium. This opens the possibility that a surface-wave spherical resonator may have important applications to refractometry.

Influence of a Sector Ground Screen on the Field of a Vertical

Antenna. The field of a short vertical antenna on a homogeneous ground was shown to be modified by the presence of a metallic screen in the form

of a circular disk and a concentric sector. The modification of the field was expressed in the form of surface integrals over the disk and the sector. Extensive numerical results were obtained for these basic integrals.

The Theory of an Antenna Over an Inhomogeneous Ground

Plane. An antenna over a flat ground plane, characterized by a variable

surface impedance, was considered theoretically. The problem was formulated in terms of the mutual impedance between two vertical dipoles. The

ground screen was taken to be in the combined form of a circular disk and

a concentric sector. An approximate solution of the problem was obtained

and the results were compared with previous investigations of closely

related work.

Curves for Ground-wave Propagation Over Mixed Land and Sea

Paths. Specific numerical results were obtained for ground-wave propagation over paths part of which are over sea and part over land. The problem

is idealized to the extent that the earth is a smooth, spherical surface. The

method is based on a previous formulation in terms of mutual impedance

between two vertical electric dipoles of an inhomogeneous spherical earth.

Amplitude and phase of the ground wave were given for various combinations of the following parameters: frequency 1000, 100, and 20 kc/s; land

conductivities 100 and 10 mmhos/meter; and a sea conductivity of 4 mhos/

meter. Most of the curves exhibit the well-known recovery effect which

occurs beyond the coastline for propagation from land towards the sea. Wave Propagation Around a Curved Boundary Containing an

Obstacle. The field of an electric dipole on a smooth spherical or cylindrical surface containing a localized obstruction was calculated- An approximate solution was obtained by combining the rigorous theory of diffraction

by a sphere and the approximate Kirchhoff diffraction theory for black

screens. The application to ground-wave propagation over mountains was

demonstrated.

Oblique Propagation of Radio Waves Across a Coastline. The

theory of mixed-path groundwave propagation was extended to cover oblique

incidence at a straight coastline. To allow for a varying water depth, the

surface impedance was allowed to change gradually from sea to land. ' The

resulting two-dimensional integral equation was solved by a perturbation

method and the solutions for an abrupt coastline and other idealized situ- ations were obtained as special cases. The apparent field singularities which

emerged in the limiting cases were shown to have a real physical significance.

Using an approximate boundary condition, the influence of a gradual elevation change at the coastline was considered also.

176
Guided Electromagnetic Waves in the Earth's Crust. A natural

waveguide for electromagnetic waves may exist in the earth's crust. The

attenuation in such a guide was calculated for an idealized model under

more or less optimum conditions. The results obtained by choosing certain

dimensionless parameters may have rather broad applications to problems

of this type.

Electromagnetic Scattering From a Sphere. The generalization of

the Lorenz-Mie theory for scattering from a homogeneous sphere to a radially

inhomogeneous sphere was carried out. In this case the scatterer consists

of a spherical body with any number of homogeneous or inhomogeneous

concentric regions. The treatment makes use of the analogy with nonuniform

transmission line theory. The results have application to radar techniques

for investigating ionized clouds.

VLF Radio Propagation in an Anisotropic Ionosphere. The theory of the propagation of electromagnetic waves in the space between a

spherical conducting earth and a concentric ionospheric reflecting layer was

treated a novel manner. The problem was idealized to the extent that the

tangential field components at the boundaries of this spherical waveguide

are related in a prescribed way. At the ground, the relation involves a scalar

surface impedance, while it was found necessary to employ a reflection

coefficient or surface impedance for the ionosphere in the form of a matrix.

A solution was sought for the total field produced by a vertical electric

dipole and explicit results were obtained by assuming azimuthal symmetry.

A representation in terms of guided waves was obtained by applying the

Watson transformation and used to obtain specific results. Excitation of Modes at Very Low Frequency. The concept of VLF

radio waves being propagated between the earth and the ionosphere in the

manner of a waveguide has proved very useful. As much neglected aspect

of the subject, however, is the manner in which the modes of propagation are

excited. A valid analysis requires that the earth's curvature and the grazing

nature of the modes be properly accounted for. An expression for the

excitation factor was obtained by using Airy integral or third-order approximations for the spherical wave functions. It was indicated that the modes

of very low attenuation may be accompanied by excitation factors much less than unity. There is evidence of this phenomenon in some old experimental

data at frequencies of the order of 25 kc/s. A mode of this type can be

imagined as becoming "detached" from the lower boundary of the earthionosphere waveguide. In this situation, the height-gain functions increase

with height and the modal characteristics depend only slightly on ground

characteristics.

Height Gain for VLF Radio Waves. The height dependence of the

field strength of VLF radio waves was considered. Using previously developed theory, the height-gain function of the first two modes was calculated

in terms of Airy functions of complex argument. For frequencies of the

order of 25 kc/s, the height-gain function reaches a maximum value at a

height of about 40 km, for a reflecting layer at about 70 km. The form of

177
the height-gain function was also shown to be dependent on the finite conductivity of the ground. An experimental curve, for 18.0 kc/s, based on a

rocket measurement shows some agreement with the theory.

Characteristics of an lnhomogeneous D-layer at VLF. The vertically polarized reflection coefficient from a horizontally graded D-layer was

calculated, using wave methods. The exponential conductivity profile was

given special attention, as being representative of the daytime quiescent

ionosphere. The results showed that the gradient of the lower ionosphere is most important in determining the magnitude of the reflection coefficient at highly oblique incidence. However, the functional relationship between the

gradient and the reflection characteristics is not simple; a sharp gradient,

for example, is not always associated with high reflection coefficients at VLF,

contrary to repeated statements in the literature. The results were also ex- tended to a study of the relation between attenuation and phase velocity of

the waveguide modes when the ionosphere is not sharply bounded.

The influence of idealized perturbations on the undisturbed profiles was

also considered- The results demonstrated, among other things, what levels

in the lower ionosphere are most effective in VLF propagation. While the

general results were complicated, some important basic principles concerning

the reflection coefficient were established.

Propagation in a Nonuniform Earth-Ionosphere Waveguide. An

approximate theory for propagation of electromagnetic waves in a curved

waveguide of variable width was developed at the Bureau, based on a direct

application of the Lorentz reciprocity theorem. The final result is in the

form of a line integral which involves the profile of the ionospheric reflecting

layer as a function of the horizontal distance. By making a number of

simplifications, valid for small perturbations, the physical consequences of

nonuniform reflecting height were made evident. It was indicated in particular that perturbations at the reflecting level introduce higher-order modes

in the waveguide. The results have application to the theory of VLF radio

wave propagation when the ionospheric heights are not constant along the

path.

Microwave Models for VLF Propagation. Work has continued on

the study of microwave models of VLF radio propagation, in collaboration

with the University of Colorado. The rectangular waveguide used as a model has approximately the same width in wavelengths, measured at 9Gc/s,

as the height of the ionosphere, at 15 kc/s. The waveguide has a modal

equation approximately the same as that of the earth-ionosphere waveguide

at VLF frequencies. Perturbations in the walls of the waveguide affect propagation through it in a manner similar to that in which ionospheric

perturbations affect propagation through the earth-ionosphere waveguide.

Experimental studies were made of propagation in the waveguide with

several different wall perturbations. It was found that wall perturbation

causes the conversion of substantial amounts of energy from one of the

propagating modes to others, as suggested by theory. Since there are 15

propagation modes in the waveguide, the effects of the perturbation are

178
noticeable at great distances from it. Furthermore, it was found that the

amount of energy converted to various propagating modes is critically dependent upon the size and shape of the perturbation. Because of this fact,

it should be possible to determine the approximate size and shape of ionospheric perturbations from field measurements at the surface of the earth.

Theory of Magnetotelluric Fields. A general theory of magnetotelluric fields was developed in connection with the combined analyses of the

geomagnetic and the teiluric (earth current) fields on the surface of the

earth. The usual objective of such investigations is to obtain information

about the earth's crustal layers, but in this case it is desired to understand

something about the source of the fields. Possible source mechanisms were

reviewed and detailed study of previous work on the theory of magnetotelluric

interpretation was carried out. A number of three-layer interpretation curves were prepared, which also can be applied to radio propagation over

a stratified conductor2.3.5. CRYOGENIC ENGINEERING

The cryogenic engineering activities, centered at the Boulder Laboratories,

provide information needed for practical applications of materials, systems,

and techniques at very low temperatures. Missiles and space programs relying on cryogenic liquids as propellants, and scientific programs requiring ex- tremely low temperatures, have increased the demand for information from

the cryogenic engineering laboratories. To cooperate in these activities, the

Bureau conducts research to determine the physical properties of materials

at cryogenic temperatures and develops methods for measuring these

properties and the characteristics of cryogenic systems. 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.

Dielectric Behavior of Dense Parahydrogen. Urgent demands by

design engineers for data on parahydrogen have resulted in extensive meas- urements by the Bureau with support from the National Aeronautics and

Space Administration (NASA). Such investigations involve studies of the

dielectric constant of parahydrogen.

The dielectric constant of a nondipolar fluid may be represented as a function of density with good accuracy by the classical formula of ClausiusMossotti. However, deviations in dielectric constant, caused by the effects

of transient dipoles, permanent multip6le moments, if present, and changes in

the molecular polarizability due to interactions with close neighbors, may

occur. The theories of such effects have developed rapidly in the past decade but

are not yet quantitatively accurate. Also, experimental data accurate enough

to clearly show these small effects are scarce. Hydrogen is not a particularly

good substance in which to study them, since neither its reduced polarizability nor its electric quadrople moment is very large. However, the avail179
ability of accurate density data recently determined by the Bureau offsets

this disadvantage. Knowing the dielectric constant accurately is important

to scientists and engineers because many instrumental techniques for determining density, liquid level, and quality of a fluid depend on capacitance

measurements.

Polarization isotherms for hydrogen have been determined from 20 to 90 °K at pressures up to 30 atm covering both the liquid and gaseous states. These isotherms rise with increasing density to a maximum, and then fall. This behavior is in qualitative accord with the prediction of theory and the

limited experimental data on related substances. These are the first data on hydrogen of sufficient precision to show departures from Clausius-Mossotti

behavior.

Superconductivity. The Bureau, in conjunction with the Atomic Energy Commission (AEC) , is investigating the energy gap in superconducting

thin films as a function of film thickness, temperature, and magnetic field.

Critical fields of tin and lead films have been determined by measuring the

magnetic field at which the energy gap vanishes. Analysis of the data in

Cryostat and magnet

used in investigating

superconductivity in

thin films. (See

p. 180.)

180
terms of the Bardeen, Cooper, Schrieffer (BCS) theory of superconductivity

is aided by computer techniques. Magnetization measurements on cold

drawn niobium wire can best be interpreted in terms of the Ginzburg-Landau,

Abrikosov, Gor'kov (GLAG) theory of superconductivity. Mathematical

research extending this theory affords better interpretation of the results. Magnetic Properties in Silicon Steel. Bureau scientists are employing a magneto-optic apparatus to observe the domain structure in silicon steels as small stresses or changes in temperature occur. Unlike the powder pat- tern technique, this apparatus reveals the complete surface domain structure without regard to the type of domain wall. The behavior under stress of a new pattern, termed the "chevron," has been noted.

Low-Temperature Seals. A program concerned with improving lowtemperature seals is being carried out by the Bureau in cooperation with the

U.S. Air Force. In these studies the thermal expansion properties and brittle

transition temperatures of about 40 elastomers, representing eight basic

polymer types, were measured. These results, combined with resilience and

differential thermal analysis measurements, are being used to predict the

usefulness of these materials as low-temperature seals. Cryogenic Literature Service. The Cryogenic Data Center's documentation unit searches the world literature for technical information pertinent to the cryogenic engineering field and promotes an awareness of such

literature to the Bureau staff and the cryogenic industry. Some 4100 new

references were coded and entered into the Center's storage and retrieval

system. Special attention was still given to low-temperature data on the

"properties of fluids" and "properties of solids" categories; thus 1500 of the

new entries were in these categories. The versatility of the computer search

program was increased when the program was converted to suit a new computer. A number of extensive bibliographies on properties of materials was

compiled during the year.

More than 2500 documents were procured from world sources for the

Bureau staff. About 600 of these were in microform, which is less costly

and often of better quality than full size copy. The staff distributed an

estimated 20,000 items of NBS literature in response to some 1500 requests.

Announcements of available material and services are sent, at three-month

intervals, to approximately 4000 persons and institutions on the Center's

mailing list. Arrangements are also being made to provide the NBS

material in microform, thus greatly reducing reproduction cost and facilitating handling. Use of technical literature in this form is becoming more

popular now that good readers and printers are available at reasonable

prices.

The documentation unit works closely with the Center's evaluation unit in

providing literature-procurement services and in bibliography retrieval.

The evaluation unit is not only a primary user of these services, but is also a major contributor of information on cryogenic literature from their compilation programs and the associated literature searching on selected topics.

181
Thermophysiral Properties of Cryogenic Materials. With support

from NASA, the Cryogenic Data Center is evaluating and compiling data on

the thermophysical properties of materials from the scientific literature. The

objective is to publish authoritative and comprehensive tables and graphs

of data in a form convenient to scientists and engineers studying cryogenic

phenomena and designing cryogenic systems. If the desired data to complete

a table are not available from the literature, values are computed from cor- relations based on theory and the properties of related materials.

Considerable progress has been made in compiling thermodynamic data on the properties of neon and carbon monoxide. The resulting tables, to- gether with property charts and a description of computational methods, will

be published by the Bureau. A temperature-entropy' diagram for nitrogen

has also been constructed and is now available. Interim reports with preliminary tables for oxygen and argon are being prepared for use while

further evaluations of these elements are in progress. Collections of data on

the surface tension values and dielectric constants of cryogenic fluids and the

electrical resistivity values for pure metals are also being evaluated.

In other work, extensive bibliographies on the thermophysical properties

of fluorine and on the thermal conductivity of cryogenic liquids were completed during the year. Bibliographies on the properties of argon and on

the saturation properties (i.e., vapor pressure, saturation densities, latent

heats, specific heats at constant saturation) of the cryogenic fluids are nearly

complete.

The thermodynamic properties of cryogenic fluids at low pressures have

been computed at the Georgia Institute of Technology under an NBS contract,

as a part of this compilation program. During the past year reports on this

activity, which include extensive tabulations of data, have been issued on

the vapor pressure and heats of vaporization and sublimation of methane,

nitrogen, and fluorine.

Fluid Flow and Heat Transfer Phenomena. Information on fluid

flow and heat transfer phenomena are necessary to provide design information

in cryogenic systems. One specific problem occurs in cryogenic liquid-vapor

flow where the mass rate of flow is often limited by choking in a restriction

such as a valve or at the exit of a system. This choking two-phase flow dif- fers from similar single phase problems and often the choking flow velocity

is reduced by an order of magnitude or more. Idealized solutions for predicting the upper and lower limits of choking two-phase flow for cryogenic

fluids have been completed. These solutions are intended for use as design

guides and as computational aids for research projects.

The characteristics of a number of pieces of equipment, particularly pumps,

are markedly changed if vapor is formed in a flowing cryogenic liquid.

Studies have been underway to determine the nucleation or bubble-forming

characteristics of cryogenic liquids. These studies show that in static systems

the pressure may be reduced below the vapor pressure before the vapor

phase occurs. Equipment exposed to the atmosphere (such as vaporizers, uninsulated

182
Liquid hydrogen cryostat for

testing fluid level sensors. Tests are made of such characteristics as repeatability and

response time. (Seep. 183.)

cryogenic fluid transfer lines, air dryers, and missile tanks) has very lowtemperature surfaces. A study concerned with the characteristics of frost

formation and heat and mass transfer on such surfaces is nearing completion.

Studies of fluid flow and heat transfer processes occurring during the

cooldown of cryogenic transfer lines are underway. Experimental data for

liquid nitrogen flow in an insulated, transfer line have been obtained. Cooldown times vary with initial flow conditions, and maximum surge pressures

measured in the system were found to be up to three times the initial driving

pressures. Analytical work to provide design data for the cooldown process

is in progress.

Cryogenic Instrumentation. A study of cryogenic instrumentation

is being conducted with support from NASA. Transducers for accurate, precise measurements of the liquid level, temperature, and mass flow of cryogenic fluids are being investigated. Both theoretical and experimental re- search are being conducted to define and extend the use of the predominate

intensive coefficients for measurements.

714-691 O—64 13 183
A state-of-the-art evaluation of commercial liquid-level point sensors for

ii \ dro^cn involving I!! manufacturers has been completed. Some of the

devices tested indicated liquid hydrogen level repeatability within 0.020 in. Response times on some types were approximately 5 and 10 msec, respectively,

as the devices were immersed and withdrawn from liquid hydrogen. Types

of devices tested included resistive, capacitive, optical, piezoelectric, magnetostrictive, and vibratory (low-frequency paddle).

Cryopropellant Research. A study of the bulk density of boiling

liquid oxygen, stimulated by the needs of rocket propulsion programs, has

been completed by the Bureau with support from NASA. Satisfactory agreement was obtained between the theoretical analysis and the experimental

research to determine the mass and volume of propellant aboard a vehicle at

Investigation of cryopropellant freezing phenomena. Propellants leaking or venting in low-pressure environments may cause solids to form in critical regions, resulting in possible failure of space vehicle propellant systems. (See

p. 184.)

184
any time. The theoretical analysis was also applied to boiling liquid hydrogen. Analytical results demonstrate the ratio of bulk density to saturated

liquid density to be a function of a parameter involving saturated liquid

properties and tank geometry. For liquid oxygen, the change in bulk

density is not large—approaching a maximum value of three percent at the

extreme conditions of large heat input rates, tall liquid columns, and small

diameters. For low-density, low latent heat (per unit volume) liquid such

as liquid hydrogen, the predicted change in bulk density is much greater.

In other work, problems in utilizing cryogenic propellants at high altitudes are being investigated. One such problem is associated with the formation

of solids in critical areas. These formations can obstruct or retard flow

and thereby cause a malfunction in the propellant system of a space vehicle.

Also of interest is the effect of micrometeorite punctures in the propellant

storage system. Either a free or obstructed flow of propellant to the ambient

low-pressure region in such cases would result, depending upon the solid

formation (plugging) characteristics of the situation. Both qualitative and

quantitative studies are now in progress on those variables which may in- fluence the solid formation in cryopropellants—particularly in liquid hydrogen and liquid oxygen. Experimental information obtained thus far

indicates that cryopropellant flow may be closely predicted by conventional

adiabatic incompressible fluid flow equations utilizing empirical (handbook)

orifice-flow coefficient data.

Refrigeration Processes. The development of methods for providing

refrigeration in the cryogenic temperature range is important to military,

industrial, and research programs. Computational work, aided by a digital

computer, is being performed on classical refrigeration processes. Correlations, resulting from the study, will make it possible to design composite

refrigeration systems with increased operating efficiency. With the partial

support of the Atomic Energy Commission, the Bureau is conducting a

theoretical study of feasible cycles adaptable to the temperature region 1.5

to 30 °K.

Expansion engines are vital components of refrigeration systems. The

development of a miniature high-speed turbine expander supported by hydrostatic (externally pressurized), helium gas-lubricated bearings is continuing.

An improved design of expander nozzles and rotors has given a 0.3116-in.-

diam turbine rotor speeds of 11,000 revolutions per second at an adiabatic

efficiency of 80 percent when operating with a pressure ratio of 4:1.

Consultation and Advisory Services. The Bureau provides cryogenic

engineering consultation and advisory services in several areas. Other

Government agencies utilize the broad experience of NBS personnel in designing equipment and handling cryogenic fluids. For example, the Bureau

is providing consultation and advisory services to the Air Force Cambridge

Research Laboratory in connection with cryogenic problems encountered in

developing a cryogenic "whole air" sampler. The sampler, carried by

rockets into the upper atmosphere, uses liquid hydrogen to condense the air

185
sample as it is being collected. This means for sampling the atmosphere

promises to be much more effective than equipment currently in use. Assistance is being given to Projects Centaur, Rover, and NERVA under

the sponsorship of National Aeronautics and Space Administration. The

Centaur, first space vehicle to use liquid hydrogen as a propellant, will be

followed by the nuclear rocket programs, Rover and NERVA, that are planning more extensive use of liquid hydrogen. The physical properties

of hydrogen are sufficiently different from other propel lants to present many

new problems to the industry. Principal contractors of these programs

receive Bureau support in the areas of ground support equipment, insulation,

instrumentation, thermodynamics, and plans, specifications, and equipment

review. In cooperation with the Central European Organization for Nuclear Research (CERN), Geneva, Switzerland, NBS personnel tested and evaluated

a hydrogen liquefier at the Bureau facilities- Under the sponsorship of the Atomic Energy Commission, the Bureau assisted in evaluating air dielectric coaxial cables as cryogenic transfer lines. Such high-frequency electrical transmission cables having suitable physical

configuration were found to be useful for transferring certain cryogenic

fluids and could substantially reduce initial investments for transferring

these fluids. Liquefied and Purified Gases. All of the liquefied gases used at the

Boulder Laboratories are now procured from commercial sources; none has

had to be produced with the NBS facilities for more than a year. The helium

liquefier is still being maintained in a ready standby condition, however,

because of some uncertainties in commercial transportation delivery. The

liquid hydrogen plant is still being used to repurify hydrogen gas collected

from liquid evaporation and for research and development on cryogenic

systems. The liquid nitrogen plants have been listed as surplus and are

available for transfer to another agency.

The approximate amounts of liquefied gas procured this year were as

follows: 830 liters of helium; 50,000 liters of hydrogen; and 370,000 liters of nitrogen. Most of these liquids were distributed to laboratory projects;

however, small amounts of liquefied and pure gases were distributed to some

12 laboratories outside the Bureau which had no other convenient source of

supply. More than 100,000 scf of hydrogen gas were collected and repurified

for laboratory use; no hydrogen gas was purchased for this purpose. About

60,000 scf of nitrogen gas were used during the year, essentially all of which was provided by the vaporization of liquid nitrogen.

2.3.6. BUILDING RESEARCH

The Bureau conducts research in chemistry, physics, and engineering to obtain data on the properties and performance of building materials, structures, and equipment; and develops methods for testing materials, mechanisms, and structures. The Bureau assists other laboratories engaged in

building research by devising techniques for accurate measurements, develop186
ing and supplying calibrated laboratory reference standards, and participating

in interlaboratory programs for checking measurement precision. Cooperation with public and private agencies to develop and improve code and

standards for safe and effective use of materials and equipment is also an

important part of the overall program.

A consultant service is maintained to advise Government agencies on building problems, and to aid public and private organizations in formulating

specifications and national standards that concern the building industry.

For example, the U.S. Air Force Academy consulted the Bureau before

choosing sealants suitable for the joints between aluminum-faced roof ele- ments of the Academy Chapel; and the National Gallery of Art called upon

the Bureau to help select a sealant for glass skylights.

Explosions on marine tankers after shipments of fuels and chemicals have

prompted the Secretary of the Treasury to appoint a "Special Committee on

Tanker Hazards." An NBS staff member serves on this committee which is studying the hazards of vapors associated with the cargoes in the ullage and

other spaces in such vessels. During the year, members of the staff conducted a symposium on Fire

Test Methods for the Committee on Fire Research of the National Academy

of Sciences—National Research Council. Another Symposium on Measurement of Thermal Radiation Properties of Solids was sponsored jointly

by the Bureau, the Air Force, and the National Aeronautics and Space

Administration.

Building Codes and Safety Standards. In performing its responsibility as the sole sponsor, the Bureau reorganized the Committee on Building

Code Requirements for Masonry of the American Standards Association

(ASA) and added 12 new members. The Committee began revising the

American Standard Building Code Requirements for Masonry about midyear

when a subcommittee prepared and reviewed a first draft, based upon re- sponses to a widely circulated request for suggestions.

The Bureau, as sole sponsor, reactivated and increased the membership of

ASA's committee on Building Code Requirements for Minimum Design

Loads in Buildings. The seven organizations and nine general-interest

members added to this Committee are all exceptionally well qualified to contribute to the Committee's work.

Through membership on committees operating under procedures of the

ASA, the Bureau assisted in (1) revising the National Electrical Code, (2)

developing plumbing, heating, and electrical standards for mobile homes

and travel trailers, (3) preparing a proposed revision to the National Plumbing Code, (4) reviewing existing standards for plumbing materials, (5)

preparing a proposed revision to the Safety Code for Elevators, and (6) preparing proposed safety codes for mechanized parking garage equipment,

cranes, derricks, and hoists; and powered platforms.

Creep and Shrinkage of Structural Lightweight Concretes. During the past three years, the Bureau, in cooperation with the Expanded

Shale, Clay, and Slate Institute, has conducted experiments on the creep and

187
Measurement of creep

in cylinders of lightweight concrete subjected to a constant

stress of 2000 psi.

Creep is important be- cause it affects the

long-term deflections

in reinforced concrete

structures. (See p. 187.)

shrinkage of lightweight aggregate concretes and has compared the results

with concretes containing normal weight aggregates.

Although creep values among individual aggregates varied a great deal,

the magnitude of creep for a concrete made with a given aggregate was found

to vary approximately linearly with the ratio of applied stress to the strength

of concrete at the time of initial loading. The investigation indicated that

both creep and drying shrinkage values were slightly higher for lightweight

concrete and that the 2-year creep of a concrete can be estimated with an

acceptable accuracy from observations made after 90 days of loading.

Joint Sealants for Building Components. With the support of the

Army, Navy, and Air Force, the Bureau maintains a joint sealant laboratory

where scientific test data on the properties and performance of sealant

formulations are obtained. These data form the basis of standard test procedures which are incorporated in both Federal and American Society

for Testing and Materials (ASTM) Specifications. Both specifications serve

as guides for architects, builders, and engineers in selecting suitable sealants.

Draft specifications for the one-component, chemically curing type (polysulfide, silicone, urethane, etc.) and the one-component, volatile curing type

(butyl, chloro-sulfonated polyethylene, acrylic, etc.) are being prepared.

Also, as a result of recent research and field experience, revisions are being

made in the specifications for two-component rubber base sealants and one- part oil and resin base types.

Waterproofing Underground Structures. The Army, Navy, and

Air Force support a Bureau program in which materials potentially useful

for waterproofing underground structures are investigated- The immediate

188
need for such information is related to missile sites, but such knowledge will

be applicable to other underground structures, including basements of houses,

and, in part, to roofs.

A device, built to simulate the damage that could occur from a backfilling

operation and from high water pressure, was employed to test a number of

materials. The test results were compared with various physical tests performed on the material such as tensile strength, bursting strength, puncture

resistance, and tear strength. Although there was considerable agreement

in the results, there were exceptions to any single test or combination of tests. The laboratory work indicates that the large number of plies usually specified

for waterproofing deep underground structures can be reduced.

Colloidal Nature of Asphalts. Recent experimental work at the Bureau shows that the asphaltene fraction (the dispersed phase) of asphalt

carries a charge, as proposed in the colloidal theory of asphalt.

In this work the asphaltenes were separated from the asphalt, suspended

in nitromethane, and introduced into a microelectrophoresis cell. Aided by

a microscope and a calibrated grid, the rate of movement of the particle at a selected potential was determined. The electrophoretic mobility of the

asphaltenes was then calculated.

Attempts to correlate electrophoretic mobility with the weathering durability of six asphalts, as determined by other means, were unsuccessful. The

charge on the asphaltenes and, consequently, polar bonding forces probably

play a minor role in asphalt durability.

Photo-oxidation Products in Plastics Identified. A sensitive col- orimetric method for measuring photo-oxidation in fiberglass-reinforced

polyester plastics was applied, with modifications, to poly (vinyl chloride),

poly (methyl methacrylate) , and cellulose acetate-butyrate plastics systems.

Weathered specimens, when treated with simple phenylenediamines, develop

a pronounced color. Spectroscopic analysis of acetic acid solutions of exposed

poly (methyl methacrylate-diamine) and cellulose acetate-butyrate-diamine

reaction products showed distinct absorbance peaks in the ultraviolet and

visible regions, respectively. Similarly, certain pure organic compounds

were found to react with diamines to produce colored products with absorb- ance peaks in the visible and ultraviolet regions. Photo-oxidation products

could then be identified by matching the absorbance peaks.

Fluid Dynamics of Plumbing. The writers of plumbing codes and

equipment standards, as well as design engineers, lack specific information on the complex fluid dynamics of plumbing needed to determine safe, eco- nomic pipe sizes, configurations, and designs.

A current study, sponsored by the National Association of Home Builders,

indicates the possibility for reducing costs and increasing the flexibility of

plumbing fixture arrangements by designs which minimize the need for vent

piping.

Test Methods for Air-Conditioning Units. Laboratory data on the

cooling capacity of air-conditioning units by three different test methods

were used for analyzing the probable measurement errors in several test

139
procedures. The three kinds of capacity measurements agreed within 4 percent in a large majority of the tests. The investigation indicated the need

for better wet-bulb and refrigerant flowmeter instrumentation as well as for more data on air mixing techniques and heat-of-mixing of various refrigerants and oil. Test Methods for Refrigerated Trucks. Laboratory investigations

leading to the development of a testing and rating method for refrigerated

trucks were carried out under the joint sponsorship of the U.S. Department

of Agriculture, the Truck-Body and Equipment Association, and the Bureau.

An apparatus for simulating the effect of solar radiation on the cooling load

of stationary refrigerated trucks was designed and constructed. Prototype

vehicles of several designs, used to study the effect of solar radiation, and

of air, moisture, and heat transmission through the body, showed that air

and moisture transmission differs significantly for different constructions.

Such studies also show that the effect of solar radiation can be satisfactorily

accounted for by a correction factor applied to the steady-state heat transfer

calculation.

Criteria for Heating and Air-Conditioning Ducts. Upon completion of a study sponsored by the Federal Housing Administration, the Bureau

recommended test procedures for evaluating the resistance of heating and

air-conditioning ducts to mold growth, odor emission, deformation at high

humidity and high temperature, bending and crushing deformation, impact

resistance, erosion, airtightness, and resistance to rupture or collapse from

internal pressure. The investigation also provided information on the characteristics of selected ducts made of cement asbestos, glass fiber, paper

laminate, and metal. Flame-spread characteristics of ducts are being investigated separately at another laboratory.

Thermal Emittance of Ceramic Oxides. As a class, the ceramic

oxides have high melting temperatures and good chemical stability when

heated in air. These properties make them useful for such applications as furnace linings, fire barriers, re-entry nose cones, and as construction materials for inboard power supplies in space vehicles. However, for these

materials to be used with maximum advantage, their high-temperature thermophysical properties must be known; one of the more important of these

properties is the thermal emissivity.

Recently, at the request of the National Aeronautics and Space Administration (NASA), the Bureau designed and constructed equipment for measuring normal spectral emittance of ceramic oxides in the 1 to 15 micron (/a) range and at temperatures up to 1800 °K. In this equipment, specimens in

the form of hollow cylinders are rotated in a furnace cavity to reduce the

temperature gradient existing between the inside and the outside of the

specimen. The ratio of the energy emitted by the specimen to that emitted

by a blackbody furnace at the same temperature is a measure of the thermal

emittance, and is automatically recorded by a double-beam spectrometer

over the range of 1 to 15 /x.

190
Automation of Thermal Emittance Measurements. A data-recording and processing attachment has been built and installed on a double-beam,

ratio-recording spectrometer. The device automatically records corrected

spectral emittance data on punched paper tape. Data from the tape can be

entered directly into an electronic digital computer for computation of total

emittance or the integrated absorptance for radiation of known spectral distribution. The attachment can also be used to compute any of these properties during a determination of spectral emittance by the selected ordinate

method. This device was developed in a program sponsored by the Air

Force.

Thermal Conductivity Reference Materials. Thermal conductivity

reference samples are needed by industry and other laboratories' to confirm

or compare thermal conductivity measurements, or to calibrate comparative

methods of conductivity measurement. Extensive measurements to explore

the stability of a chromium-nickel alloy, and the degree to which it may be

affected by its thermal history, have been made using electrical resistance

measurements. Thermal conductivity results made by a cooperating laboratory over the temperature range 200 to 1100 °C on a sample of this alloy

agree with Bureau results within two percent. Sixteen samples of this alloy

have now been made available to other laboratories, on a preliminary basis.

Preliminary work has begun on a cerammed microcrystalline glass in a program to develop a much needed reference material of moderate thermal

conductivity. This work was supported in part by the Navy.

Measurement of the spectral emittance of a ceramic oxide specimen at 1400 °K.

Because the ceramic oxides have high melting temperature and good

chemical stability, they are useful in furnace linings, fire barriers, rocket nose

cones, and inboard power supplies in space vehicles. For these applications,

however, the high-temperature thermophysical properties, such as thermal

emissivity, of these materials must be carefully charted. (See p. 190.)

191
Thermal Conductivity Measurements by Radial Heat Flow. In connection with thermal conductivity measurements on powder insulations

at high temperatures, the Bureau made a mathematical analysis of line heat source arrangements for a radial heat flow system. The study showed that

that the positions of the axial heater and inner radius thermocouples of a

radial-flow system could be interchanged, with material experimental advantages in some cases. For example, one thermocouple can serve in place of

several, and can be protected against contamination, or be renewed readily,

without disturbing a measurement.

Performance Specification for Insulated Flat-Roof Constructions.

A draft of a performance specification for insulated flat-roof construction

subjected to moisture has been prepared for the Army, Navy, and Air Force,

the sponsors of the investigation. The specification gives performance re- quirements for insulated roof constructions, for ordinary occupancy and

climates, that are capable, if wetted, of self-drying under seasonal in-service

conditions as a result of solar heating of the roof. The studies showed that

after the leak is patched, an insulated flat roof, if it is self-drying, will re- cover most of its insulating value, without replacing the insulation or the

roofing.

Heat of Hydration of Portland Cement. As portland cement hydrates, a substantial amount of heat is released. To prevent damage to massive structures, such as large dams, by the accumulation and subsequent

release of the heat generated within the structure, designers must know the

heat of hydration of various cements. Calorimeters for determining these

data are calibrated with reagent-quality zinc oxide. Heat-of-solution values

currently used for zinc oxide were determined in 1933.

One of three sets of equipment used to check cement and concrete testing

apparatus by the NBS Cement and Concrete Reference Laboratory in a joint

U.S. Government—ASTM program. The service is available throughout the

United States and Canada.

192

I
Recently, using a precision calorimeter, the Bureau determined the heat

of solution of 12 lots of reagent-quality zinc oxide obtained from different

manufacturers in the United States, Great Britain, Germany, and Japan.

Results showed an average value only slightly higher than the currently

accepted value. Further, no significant differences in heat of solution were found among the 12 lots. Consequently, measurements made with different

cement calorimeters, wherever calibrated, should not differ from each other

due to differences in the source of the standardizing substance.

Electron Capture of Combustion Inhibitors. Certain gaseous flameinhibiting agents show high electron attachment coefficients. Results of

electron attachment studies on 23 halogenated hydrocarbons show that they

exhibit electron attachment coefficients significantly higher than that of

oxygen. There appeared, with some exceptions, to be qualitative correlation

between electron attachment and flame extinguishment effectiveness of the

inhibitors. However, the significance of this finding is not clear, considering

that there are compounds exhibiting high electron attachment coefficients

which cannot be considered useful as flame inhibitors.

Surface Flame Propagation. The radiant-panel flame-spread test method, previously developed by the Bureau, has been adopted as an Interim

Federal Standard and as a tentative test method for research and development purposes by the ASTM. Performance of this test results in a flamespread index composed of two factors, representing the ignition sensitivity

and the maximum rate of heat generation by the material. Recently completed studies on selected cellulose-type materials have delineated some

important physical and thermal properties which influence surface flame

propagation on simple and composite slabs. Results of these studies indicate

that flame propagation in these materials consists of progressive ignition of

the solid when a characteristic temperature is reached.

Fire Research Contracts. The Bureau, in cooperation with the Office

of Naval Research, the Office of Civil Defense, the Advanced Research Projects Agency, and the National Science Foundation, is supporting fundamental work in the field of self-ignition phenomena and the mechanism of

fire extinguishment. Two aspects of this work have been completed by publication of the findings. The first of these consisted of a study of combustion

phenomena by means of mathematical techniques. The refinements introduced in this study for predicting performance of self-heating materials,

show that the finite difference method developed provides a significant improvement over other mathematical techniques previously available.

In the second part of the study, the field of fire extinguishment, research

for the purpose of clarifying the mechanism by which chemical powders are

effective in terminating combustion reactions, has been studied. It was

found that the introduction of 6 percent potassium vapor into a methane

diffusion flame had no inhibition effect, but bromine compounds introduced

at the same concentration proved to be very effective inhibitors.

193
2.3.7. WEIGHTS AND MEASURES

The control over commercial weighing and measuring in the United States

is principally the responsibility of the political subdivisions of the Federal

government—the States, counties, and cities. Such local control allows

problem solutions to be patterned to local conditions. However, to avoid

the possibility of 50 different weights and measures systems, the U.S. Department of Commerce—and through it, the National Bureau of Standards

has been charged by the Congress with the custody, maintenance, and development of the national standards of measurement, and with the provision

of means and methods for making measurements consistent with those standards. To assist the State weights and measures programs, the Bureau tests and calibrates State standards and standard measuring apparatus and provides technical advisory services. To assure uniformity in weights and

measures laws and in methods of inspection, the Bureau extends general

cooperation to State weights and measures officials. To carry out this program, the Bureau maintains an Office of Weights

and Measures which is responsible for (1) technical assistance to the States

and to business and industry in the area of measurement; (2) the design,

construction, and use of weights and measures standards and of instruments

associated with such standards; (3) the training of weights and measures

officials in the technical aspects of their programs; and (4) the collection,

arrangement, and dissemination of technical data on measurement units

and systems.

Technical Assistance Program. With increases in personnel, the Office of Weights and Measures has expanded its technical services, and assistance is now being given on a continuing basis in the design of State

laboratory facilities. During the year, plans for such facilities have been

provided to the States of New Mexico, Pennsylvania, Tennessee, and

Wisconsin.

Package-checking techniques for products that are difficult to check—for

example, aerosol containers and frozen food packages—were outlined and

demonstrated. For such products, dependable quantity determination methods have not previously been available in convenient form for weights and

measures officials. A preliminary investigation was made of pipe meter provers, with more

detailed studies planned. In an investigation undertaken because of the

recent use of small flowmeters in the marketing of fuel oil, a system was

developed for the testing of so-called "slow-flow" meters. An extensive

investigation of the accuracy of rental-car odometers was completed.

A new form of communication with the weights and measures officials of

the Nation, the Weights and Measures Tech Memo, was initiated. This memo

is issued at practical intervals to selected addresses, principally to State

offices. Thus information on significant technical developments is transmitted to the operating level.

194

I
A booklet containing simplified test procedures has been prepared for use

in the testing of commerical weighing and measuring devices. These procedural outlines list the minimum steps to be followed in an official examination.

New Standards Designed. New mass standards made of stainless steel were recently designed. Orders for a set of metric weights of this design

have been placed with manufacturers, as part of a Latin-American Standards

development program.

In studies to improve State and industrial equipment, glass capacity measures were developed which are both easy to use and nearly automatic

in operation and, at the same time, give highly accurate results; and a 100-

gallon stainless steel capacity measure was designed for use as a capacity

standard and also for use in the calibration of sanitary meters.

Technical Training. Technical training of State and local weights and

measures officials falls into three categories: formal courses of one-week

duration for small classes of supervisory personnel in a training laboratory

at the Bureau; 2-, 3-, or 4-day formal courses conducted in the various States

for all State and local officials; and informal training at the Bureau and in

the field to cover laboratory procedures and the use of special testing equipment. Such technical training undoubtedly is a factor in the rapidly developing uniformity and effectiveness of weights and measures regulatory

services in the United States. This year, in line with the desire to reach

the greatest number of weights and measures officials possible, self-training

aids were created as a supplement to the formal training programs.

Standard glass capacity measures recently

designed at the Bureau for weights and

measures officials are

easy to use, nearly au- tomatic in operation,

and highly accurate. (See p. 195.)

195
New design for mass standards made of stainless steel. A metric set of this

design is being acquired for the Latin American standards program. (See

p. 195.)

Technical Information. A basic responsibility is 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 for technical information is handled every year. Two indexed collections of books—an archival collec- tion and a reference collection—and many historical documents comprise a weights and measures library. This library affords the staff and outside

researchers and students complete references on the history and present

status of weights and measures. National Conference on Weights and Measures. The Bureau sponsors an annual National Conference on Weights and Measures where

weights and measures officials, representatives of various agencies of the

Federal government and of equipment manufacturers and users, and others

interested in orderly and effective weights and measures control are as- sembled for relatively informal meetings. The Conference sessions develop

technical and general recommendations for weights and measures administration, contribute to interstate coordination of weights and measures activ196
ity, and explore the entire area of this economically important segment of

governmental regulatory service. Among Conference accomplishments are

a Model State Law on Weights and Measures, and model regulations covering

devices and packages. The Model Law is included among recommended

legislative efforts of the Council of State Governments.

At the 48th National Conference held during the year, 39 States, the District of Columbia, Canada, Puerto Rico, England, Austria, and Trinidad

and Tobago were officially represented among a total attendance of 499.

Principal topics discussed were package standardization and labeling, slowflow meter tolerances, and rental-car odometer accuracy. Talks were presented on such subjects as the President's Consumer Advisory Council, the

International Organization of Legal Metrology, domestic and international

business, consumer protection in Great Britain, the Truth in Packaging Bill,

and problems in the determination of moisture and quantity control.

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 two Deputy Directors, one who is responsible

for basic standards and services, and the other for technological standards and services. The 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 the relocation of the Bureau to new laboratories which are under constuction at Gaithersburg, Maryland. Program activities are conducted in 24 scientific divi- sions. 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. Sixteen of the divisions are located in Washington and eight in Boulder. Below

the section level, the staff is organized into project groups which may be easily regrouped.

DIRECTOR

Allen V. Astin

DEPUTY DIRECTORS

Robert D. Huntoon

I. C. Schoonover

Associate Directors

L. S. Taylor

R. S. Walleigh

W. A. Wildhack

Manager, Boulder Laboratories

R. B. Scott

*As of June 30, 19C8.

197
Assistants to the Director

G. E. Auman

W. S. Bussey

W. H. Gammon

A. T. McPherson

Assistant Directors and Senior Research Fellows

U. Fano

K. Shuler

Senior Research Fellows

C. ElSENH ART

J. R. Wait

Staff Advisers

Patent Adviser D. Robbins

Program Adviser C. N. Coates

NBS WASHINGTON

SCIENTIFIC DIVISIONS AND SECTIONS

(In numerical order)

ELECTRICITY

Chief

Resistance and Reactance

Electrochemistry

Electrical Instruments Magnetic Measurements

Dielectrics High Voltage

Absolute Electrical Measurements

C. H. Pace

C. Peterson

W. J. Hamer

F. M. Defandorf

I. L. COOTER

J. D. Hoffman

F. R. Kotter

F. K. Harris

METROLOGY

Chief

Assistant Chief

Photometry and Colorimetry

Refractometry

Photographic Research

Length

Engineering Metrology

Mass and Volume

Chief

Assistant Chief for Thermodynamics

Temperature Physics

Heat Measurements

Cryogenic Physics

Equation of State

Statistical Physics

HEAT

RADIATION PHYSICS

Chief

X-ray

Radioactivity

Radiation Theory

High Energy Radiation

Radiological Equipment

Nucleonic Instrumentation

Neutron Physics

A. G. McNish

D. B. Judd

L. E. Barbrow

F. E. Washer

C. S. McCamy

T. R. Younc

I. H. Fullmer

P. E. Pontius

R. P. Hudson

C. W. Beckett

J. F. Swindells

D. C. Ginnings

E. Ambler

J. Hilsenrath

M. S. Green

H. W. Koch

H. 0. Wyckoff

W. B. Mann

M. Berger, Acting

J. E. Liess, Acting

S. W. Smith

L. Costrell

R. S. Caswell

198

I
ANALYTICAL AND INORGANIC CHEMISTRY

Chief

Assistant Chief

Consultant

Pure Substances

Spectrochemistry

Solution Chemistry

Standard Reference Materials

Applied Analytical Research

Crystal Chemistry

Chief

Consultants

Sound

Pressure and Vacuum

Fluid Mechanics

Engineering Mechanics

Rheology

Combustion Controls

MECHANICS

POLYMERS

Chief

Consultants on Leather

Paper

Plastics Rubber

Textiles

Macromolecules : Synthesis and Structure Polymer Chemistry

Polymer Physics

Polymer Characterization

Polymer Evaluation and Testing

Applied Polymer Standards and Research

Dental Research

METALLURGY

Chief

Assistant Chief

Consultant

Special Assistant

Engineering Metallurgy

Metal Reactions

Metal Physics

Electrolysis and Metal Deposition

INORGANIC SOLIDS

Chief

Assistant Chief

Consultant

Vitreous State Group

Engineering Ceramics

Glass

Solid State Chemistry

Crystal Growth

Physical Properties

Crystallography

BUILDING RESEARCH

Chief

Consultant

Structural Engineering

Fire Research

Mechanical Systems

Organic Building Materials

Codes and Safety Standards Heat Transfer

Inorganic Building Materials

Metallic Building Materials

H. C. Allen

R. G. Bates

C. P. Saylor

F. L. Howard

B. F. Scribner

R. G. Bates

J. L. Hague

J. K. Taylor

H. S. Peiser

B. L. Wilson

J. M. Frankland

E. C. Lloyd

R. K. Cook

D. P. Johnson

G. B. Schubauer

L. K. Irwin

R. S. Marvin

F. R. Caldwell

G. M. Kline

J. R. Kanacy

R. B. Hobbs

S. G. Weissberc

L. A. Wood

H. F. Schiefer

D. McIntyre

L. A. Wall

E. Passaglia

N. P. Bekkedahl

R. D. Stiehler

R. B. Hobbs

W. T. Sweeney

L. M. Kushner

G. A. Ellinger

L. L. Wyman

H. C. Burnett

S. J. Rosenberg

G. A. Ellinger

L. M. Kushner

A. Brenner

A. D. Franklin

C. H. Hahner

E. R. Lippincott

A. B. Bestul

M. B. Burdick

C. H. Hahner

Vacant

F. Ordway

J. B. Wachtman, Jr. H. F. McMurdie

A. A. Bates

W. F. Roeser

D. Watstein

A. ¥. Robertson

P. R. Achenbach

W. W. Walton

Vacant

H. E. Robinson

B. E. Foster

W. N. Harrison

714-691 O—64 14 199
APPLIED MATHEMATICS

Chief

Assistant Chief

Consultants

Numerical Analysis

Computation

Statistical Engineering

Mathematical Physics

Operations Research

E. W. Cannon

F. L. Alt

W. J. YOUDEN

Mrs. Ida Rhodes

M. Newman

D. I. MlTTLEM AN

J. M. Cameron

W. H. Pell

A. J. Goldman

DATA PROCESSING SYSTEMS

Chief

Technical Assistant

PILOT

Research Information Center and Advisory

Service on Information Processing

Components and Techniques

Computer Technology

Measurements Automation

Engineering Applications

Systems Analysis

Chief

Spectroscopy

Infrared Spectroscopy

Far Ultraviolet Physics

Solid State Physics

Electron Physics

Atomic Physics

Plasma Spectroscopy

Chief

Engineering Electronics

Electron Devices

Electronic Instrumentation

Mechanical Instruments

Basic Instrumentation

ATOMIC PHYSICS

INSTRUMENTATION

PHYSICAL CHEMISTRY

Chief

Consultants

Thermochemistry

Surface Chemistry

Organic Chemistry

Molecular Spectroscopy

Elementary Processes Mass Spectrometry

Photochemistry and Radiation Chemistry

S. N. Alexander

M. R. Fox

J. P. Nicro

Miss M. E. Stevens

R. D. Elbourn

J. A. Cunnincham

R. T. Moore

J. P. Nicro

N. Alexander, Acting

K. G. Kessler

W. C. Martin, Jr. E. K. Plyler

R. P. Madden

H. P. R. Frederikse

J. A. Simpson

H. BOYNE

W. L. Wiese

G. F. Montgomery

G. Shapiro

C. P. Marsden

F. Montgomery, Acting

A. Wexler

J. Stern

M. B. Wallenstein

W. L. Clinton

E. J. Prosen

M. B. Wallenstein

R. Klein

H. S. Isbell

D. E. Mann

R. E. Ferguson

H. Rosenstock

J. R. McNesby

Chief

OFFICE OF WEIGHTS AND MEASURES

ADMINISTRATIVE AND SERVICE DIVISIONS

M. W. Jensen

Office of Technical Information

Accounting

Personnel

Administrative Services

Shops

Supply

Management Planning

Budget

Internal Audit

Plant

NBS Library

W. R. Tilley

J. Seidenberg

G. R. Porter

H. P. Dalzell

F. P. Brown

G. B. Kefover

A. J. Muller

J. E. Skillington

J. Seidenberg, Acting

M. B. Goetz, Acting

Miss S. Jones

200
BOULDER DIVISIONS

Manager, Boulder Laboratories

Consultants

Mathematics Group and Computation Facility

Mathematical Physics and Educational Director

Statistics Physics of the Atmosphere

Communications Liaison Officer Executive Officer and Chief of Administrative Division

Technical Information Officer

R. B. Scott

J. J. Sopka

E. H. Brown

E. L. Crow

D. M. Gates

Allen Barnabei

S. W. J. Welch

J. R. Craddock

CRYOGENIC ENGINEERING LABORATORY

Chief

Cryogenic Processes Cryogenic Properties of Solids

Properties of Cryogenic Fluids

Cryogenic Technical Services

B. W. Birmingham, Acting

B. W. Birmingham

R. H. Kropschot

R. J. Corruccini

V. J. Johnson

CENTRAL RADIO PROPAGATION LABORATORY

Chief

Assistant Chief

Chief, Office of CRPL Liaison and Program Development

Consultant, Radio Wave Propagation

C. G. Little

J. W. Herbstreit

A. H. Shapley

J. R. Wait

IONOSPHERE RESEARCH AND PROPAGATION

Chief

Assistant Chief

Assistant to Chief for Technical Planning and Coordination

Consultants

Ultra Low Frequency Research

Low Frequency and Very Low Frequency Research

Ionosphere Research

Prediction Services

Sun-Earth Relationships

Field Engineering

Radio Warning Services

Vertical Soundings Research

R. W. Knecht

T. N. Gautier

J. A. Kemper

D. K. Bailey

H. H. Howe

W. H. Campbell

A. G. Jean

K. Davies Mrs. M. Leftin

T. E. Van Zandt

H. G. Sellery

Miss J. V. Lincoln

J. W. Wright

TROPOSPHERE AND SPACE TELECOMMUNICATIONS

Chief

Assistant Chief for Research and Development

Consultant—Terminal Equipment

Consultant—Lower Atmospheric Physics

Data Reduction Instrumentation

Radio Noise

Tropospheric Measurements

Tropospheric Analysis

Spectrum Utilization Research

Radio Meteorology

Lower Atmosphere Physics

RADIO SYSTEMS

Chief

Assistant Chief

Assistant Chief

Applied Electromagnetic Theory

High Frequency and Very High Frequency Research

Frequency Utilization Modulation Research

Antenna Research

Radiodetermination

K. A. Norton

R. S. KlRBY

E. F. Florman

B. R. Bean

W. E. Johnson

W. Q. Crichlow

M. T. Decker

P. L. Rice

A. P. Barsis

R. E. McGavin

R. E. McGavin, Acting

R. C. Kirby

D. W. Patterson

W. F. Utlaut

J. R. JOHLER

L. H. Tveten

G. W. Haydon

C. C. Watterson

H. V. Cottony

G. Hefley

201
UPPER ATMOSPHERE AND SPACE PHYSICS

Chief

Assistant Chief

Consultants

Upper Atmosphere and Plasma Physics

High Latitude Ionospheric Physics

Ionosphere and Exosphere Scatter Airglow and Aurora

Ionospheric Radio Astronomy

E. K. Smith, Jr.

F. L. Taylor

R. J. Slutz

D. K. Bailey

R. M. Gallet

H. J. A. Chivers

K. L. Bowles

F. E. Roach

R. S. Lawrence

RADIO STANDARDS LABORATORY

Chief

Assistant Chief for Planning and Coordination

Consultant

RADIO STANDARDS PHYSICS

Chief

Assistant Chief

Consultant

Assistant Chief for Technical Planning and Coordination

Frequency and Time Dissemination

Radio and Microwave Materials

Atomic Frequency and Time Interval Standards

Radio Plasma

Microwave Physics R.

J. M. Richardson

E. C. Wolzien

D. M. Kerns

Yardley Beers

G. E. Hudson

P. F. Wacker

W. D. Goring

A. H. Morgan

J. L. Dalke

R. C. MOCKLER

K. B. Persson

W. Zimmerer, Acting

RADIO STANDARDS ENGINEERING

Chief

Assistant Chief

Assistant to the Chief for Technical Planning and Coordination

Consultants

Coordinator Calibration Service

High Frequency Electrical Standards

High Frequency Calibration Services

High Frequency Impedance Standards

Microwave Calibration Services

Microwave Circuit Standards

Low Frequency Calibration Services

R. C

F. D.

G. E. ScHAFER

H. W. Lance

W. J. Anson

R. W. Beatty

M. C. Selby

W. F. Snyder

C. M. Allred

Powell, Acting

R. C. Powell

R. E. Larson

M. B. Hall

Weaver, Acting

JOINT INSTITUTE FOR LABORATORY ASTROPHYSICS

Chairman

NBS GROUP

FIELD ESTABLISHMENTS

Visual Landing Aids Field Laboratory

Master Railway Track Scale Depot

Materials Testing Laboratories:

Radio Transmitting Station WWV

Radio Transmitting Station WWVL

Radio Transmitting Station WWVL-WWVB

Central Radio Propagation Laboratory Field Stations:

ALASKA

Anchorage

Barrow

ANTARCTICA

Byrd Station**

Eights Station**

Pole Station**

USNS Eltanin (Floating

Research Vessel ) * *

AUSTRALIA

Cook**

BOLIVIA

La Paz**

BRAZIL, S.A. Sao Jose dos Campos*

CALIFORNIA

Port Arguello

L. M. Branscomb

Areata, Calif. Clearing, 111. Denver, Colo. San Francisco, Calif. Seattle, Wash.

Greenbelt, Md.

Sunset, Colo. Fort Collins, Colo.

CANADA

Baie St. Paul

Cape Jones**

Great Whale River**

Frobisher Bay**

CHILE

Concepcion**

•Contract or Mutual Cooperation.

202
COLORADO

Beulah

Brighton

Chalk Cliff Site Cheyenne Mountain

Erie

Fritz Peak

Green Mountain Mason

Gunbarrel Hill Haswell

Hygiene

Karval

Kendrick

Kolb

Lafayette

Table Mesa

Sunset COLOMBIA

Bogota**

GREENLAND

Thule**

Godhavn**

Narssarssuaq**

HAWAII

xMaui (WWVH)

Kekaha

Mt. Haleakala

ICELAND

Keflavik**

Reykjavik**

ILLINOIS

Long Branch

INDIA

New Delhi**

JAPAN

Ohira**

KANSAS

Garden City

MALAYA

Singapore**

MISSOURI

Warrensburg

MOROCCO

Rabat**

NEBRASKA

Shickley

NIGERIA

Ibadan**

OKINAWA

Onna**

Okuma**

OKLAHOMA

Altus

PANAMA CANAL ZONE

Balboa**

PERU

Lima* * Jicamarca Radio

Observatory

PHILIPPINE ISLANDS

Baguio

SOUTH AFRICA

Pretoria**

SWEDEN

Enkoping**

UTAH

Salt Lake City**

VIRGINA

Fort Belvoir Front Royal

Wallops Island

WYOMING

Bill

Contract or Mutual Cooperation.

3.2. SUMMARY OF NBS STAFF

Washington Boulder Total

Total permanent staff 2,350 1,168 3,518

Other staff* 404 238 642

Total on rolls 2,754 1,406 4, 160

Research associates and guest workers 163 34 197

Total on rolls at NBS** 2,917 1, 440 4, 357

Professional staff*** Physicists 423 221 644

Chemists 280 7 287

Engineers 166 161 327

Mathematicians 50 59 109

Other 76 19 95

995 467 1,462

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

**Asof June 30, 1963. ***Full-time permanent (excludes any under *) as of December 31, 1962.

203
3.3. FINANCIAL DATA ON NBS PROGRAM

The activities of the National Bureau of Standards are financed from

three sources: from appropriations provided hy the Congress; from payments 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 1963:

Program and source of financing

Supported by NBS appropriations:

Operating programs:

Research and technical services. Special foreign currency program

Subtotal

Construction and facilities program:

Plant and facilities Construction of facilities

Subtotal

Total NBS appropriation

Supported by other funds:

Research and development programs:

Other Federal agencies

Nongovernmental sources

Calibrations, testing, standard

samples, and other technical

services

Reimbursable administrative services

Total supported by other funds.

Total program

Obligations incurred (rounded)

$27, 782, 000

710, 000

7, 204, 000

2, 423, 000

14, 416, 000

168, 000

$28, 492, 000

9, 627, 000

14, 584, 000

5, 462, 000

856, 000

$38, 119, 000

20, 902, 000

59, 021, 000

3.4. ADVISORY COMMITTEES

STATUTORY VISITING COMMITTEE

(Reports annually to Secretary of Commerce on NBS activities (Dates indicate expiration of appointment)

Dr. Lloyd V. Berkner, President, Graduate Research Center, Inc. (1963), Chairman

Professor Frederick Seitz, President, National Academy of Sciences (1966)

Mr. Crawford H. Greenwalt, President, E. I. du Pont de Nemours & Co. (1964)

Professor Charles H. Townes, Provost, Massachusetts Institute of Technology (1965) Dr. E. R. Piore, Vice President, Research and Engineering, International Business

Machines Corporation (1967)

204
TECHNICAL ADVISORY PANELS

At the request of the National Bureau of Standards, the National Academy of SciencesNational Research Council, in cooperation with the leading scientific and technical

societies, appoints each year a number of technical advisory panels. The panels make

a continuing evaluation of NBS programs with respect to the needs of the Nation's

scientific and technological community. The panels provide advice and information in

specific technical areas for use by the NBS Director and his staff in the formulation

and execution of NBS programs. Cooperating societies are: American Ceramic Society (ACerS) ; American Chemical

Society (ACS) ; American Institute of Chemical Engineers (AIChE) ; Institute of Electrical and Electronic Engineers (IEEE) ; American Institute of Mining, Metallurgical,

and Petroleum Engineers (AIME) ; American Institute of Physics (AIP) ; American

Society of Civil Engineers (ASCE) ; American Society of Mechanical Engineers

(ASME) ; and Conference Board of the Mathematical Sciences (CBMS)

Dr. Paul D. Foote, National Research Council, Executive Secretary

Advisory Panel to Electricity Division

Prof. W. A. Lewis, Illinois Institute of Technology, Chairman (IEEE)

Dr. William G. Amey, Leeds & Northrup (IEEE)

Dr. Richard M. Bozorth, Short Hills, N.J. (AIP)

Dr. John Brainerd, University of Pennsylvania (IEEE)

Prof. Henry B. Linford, Columbia University (ACS)

Mr. J. T. Lusignan, The Ohio Brass Company (IEEE)

Prof. John G. Trump, Massachusetts Institute of Technology (AIP)

Dr. Ernest Weber, Polytechnic Institute of Brooklyn (IEEE)

Advisory Panel to Metrology Division

Dr. Brian O'Brien, Pomfret, Conn., Chairman (AIP)

Prof. Isay A. Balinkin, University of Cincinnati (ACerS)

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, University of Rochester (AL)

Mr. Floyd W. Hough, Arlington, Virginia (ASCE)

Dr. Elmer Hutchisson, American Institute of Physics (AIP)

Mr. J. J. Moran, Kimble Glass Company (ACerS)

Mr. Louis Polk, Dayton, Ohio (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, Duke University (AIP)

Dr. Burgess H. Jennings, Northwestern University (ASME)

Prof. Joseph Kestin, Brown University (ASME)

Dean R. B. Lindsay, Brown University (AIP)

Dr. Charles Squire, Agriculture and Mechanical College of Texas (AIP)

Prof. Glenn C. Williams, Massachusetts Institute of Technology ( AICE)

Advisory Panel to Radiation Physics Division

Dr. H. M. Parker, General Electric Company, Chairman (AIP)

Mr. 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 (IEEE)

Prof. Harold A. Lamonds, North Carolina State College (IEEE)

Prof. George T. Reynolds, Palmer Physical Laboratory (AIP)

Dr. Leonard Schiff, Stanford University (AIP)

205
Advisory Panel to Analytical and Inorganic Chemistry Division

Dr. T. Ivan Taylor, Columbia University, Chairman (ACS)

|)u. Ci.akk E. linn Ki n, The College of Wooster (ACS)

Dr. Norman 1). ( :<j(.(;i:sn ail, 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)

Prof. HenryTai.be, Stanford University (ACS)

Dr. Charles E. White, University of Maryland (ACS)

Advisory Panel to Mechanics Division

Prof. S. R. Beitler, Ohio State University, Chairman (ASME)

Prof. Lynn S. Beedle, Lehigh University ( ASCE)

Prof. Arthur T. Ippf.n, 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 Polymers Division

Dr. C. G. Overbercer, Polytechnic Institute of Brooklyn, Chairman (ACS)

Dr. Raymond F. Boyer, Dow Chemical Company (ACS)

Dr. J. H. Dillon, Textile Research Institute (AIP)

Dr. Milton Harris, Harris Research Laboratories, Inc., (ACS)

Dr. Frank C. McGrew, E. I. du Pont de Nemours & Co. (ACS)

Dr. Charles C. Price, University of Pennsylvania (ACS)

Dr. J. F. Downie Smith, Carrier Research and Development Company (ASME)

Dr. Charles Scott Venable, Wallingford, Pa. (ACS)

Advisory Panel to Metallurgy Division

Mr. Francis L. Laque, International Nickel Company. Chairman (ACS)

Dr. D. J. Dienes, Brookhaven National Laboratory ( AlP)

Dr. Morris Eugene Fine, Northwestern University (AIME)

Mr. A. R. Lytle, National Academy of Sciences-National Research Council (AIME)

Dr. Oscar Marzke, United States Steel Corporation (AIME)

Prof. E. F. Osborn, Pennsylvania State University ( ACerS)

Dr. Joseph A. Pask, University of California (ACerS)

Dr. Albert J. Phillips, American Smelting and Refining Company (AIME)

Mr. D. B. Rossheim, M. W. Kellogg Corporation (ASME)

Mr. J. H. Scaff, Bell Telephone Laboratories (AIME)

Prof. Robb M. Thompson, University of Illinois (AIP)

Advisory Panel to Inorganic Solids Division

Dr. Norbert J. Kreidl, Bausch and Lomb Optical Company, Chairman (ACerS)

Dr. Orson L. Anderson, Summit, New Jersey ( ACerS)

Prof. C. Ernest Birchnall, University of Delaware ( AL)

Dr. Joseph E. Burke, General Electric Research Laboratory (ACerS)

Dr. James R. Johnson, Minnesota Mining and Manufacturing Company (ACerS)

Prof. J. W. Mitchell, University of Virginia ( AL)

Dr. E. F. Osborn, Pennsylvania State University (ACerS)

Dr. Ralston Russell, Jr., The Ohio State University (ACerS)

Mr. Karl Schwartzwalder, General Motors Corporation (ACerS)

Prof. Pierce Selwood, University of California (ACS)

Advisory Panel to Building Research Division

Dr. W. C. Hansen, Valpariso, Indiana, Chairman (ACS)

Prof. Jesse H. Day, Ohio University (ACS)

Dr. Albert G. H. Deitz, Massachusetts Institute of Technology (ASCE)

Dr. J. V. Fitzgerald, Tile Council of America, Inc. (ACerS)

Prof. Robert A. Hechtman, The George Washington University (ASCE)

Prof. James T. Lendrum, University of Florida ( ALA)

Dean Warren L. McCabe, Polytechnic Institute of Brooklyn ( AICE)

Dr. John S. Parkinson, Johns-Manville Products Corporation (AIP)

Prof. E. R. Queer, The Pennsylvania State University ( AL)

Mr. Raymond C. Reese, Toledo, Ohio (ASCE)

206
Advisory Panel to Applied Mathematics Division

Prof. George E. Forsythe, Stanford 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. Peter D. Lax, New York University (CBMS)

Dr. Elliott W. Montroll, Institute for Defense Analysis (CBMS)

Prof. R. D. Richtmyer, New York University (CBMS)

Dr. J. Barkley Rosser, Cornell University (CBMS)

Prof. M. M. Schiffer, Stanford University (CBMS)

Advisory Panel to Data Processing Systems Division

Dr. Alston S. Householder, Oak Ridge National Laboratory, Chairman (CBMS)

Prof. George E. Forsythe, Stanford University (CBMS)

Dr. Alan J. Hoffman, International Business Machines Corporation (CBMS)

Mr. John C. McPherson, International Business Machines Corporation (IEEE)

Prof. Charles L. Miller, Massachusetts Institute of Technology (ASCE)

Mr. William Papian, Massachusetts Institute of Technology (IEEE)

Prof. Raymond Pepinsky, Pennsylvania State University (AIP)

Prof. William H. Radford, Massachusetts Institute of Technology (IEEE)

Prof. Morris Rubinoff, University of Pennsylvania (IEEE)

Advisory Panel to Atomic Physics Division

Prof. R. H. Dicke, Princeton University, Chairman (AIP)

Prof. Benjamin Bederson, New York University (AIP)

Dr. Bruce H. Billings, Baird-Atomic, Inc. (AIP)

Prof. Peter Franken, University of Michigan (AIP)

Prof. Jesse L. Greenstein, California Institute of Technology (AD

Prof. Vernon W. Hughes, Sloane Laboratory (AIP)

Prof. Mark G. Ingrham, University of Chicago (AIP)

Dr. Benjamin Lax, Massachusetts Institute of Technology (AIP)

Dr. M. Kent Wilson, Tufts University (ACS)

Advisory Panel to Instrumentation Division

Mr. R. W. Larson, General Electric Research Laboratories, Chairman

Dr. A. 0. Beckman, Beckman Instruments, Inc. (AL)

Mr. Ivan G. Easton, General Radio Company (IEEE)

Mr. D. G. Fink, Philco Corporation (IEEE)

Mr. William R. Hewlett, Hewlett-Packard Company (IEEE)

Dr. R. J. Jeffries, Data-Control Systems, Inc. (AL)

Col. J. Z. Millar, Western Union Telegraph Company (IEEE)

Mr. Leon Podolsk y, Sprague Electric Company (IEEE)

Advisory Panel to Physical Chemistry Division

Prof. Henry Eyring, University of Utah, Chairman (ACS)

Dr. A. 0. Allen, Brookhaven National Laboratory (ACS)

Dr. Paul Cross, Mellon Institute of Industrial Research (ACS)

Dr. Benjamin P. Dailey, Columbia University (ACS)

Dr. Joseph 0. Hirschfelder, University of Wisconsin (ACS)

Prof. Hans H. Jaffe, University of Cincinnati (ACS)

Dr. Daniel R. Stull, The Dow Chemical Company (ACS)

Advisory Panel to Cryogenic Engineering Division

Dr. Clyde McKinley, Air Products Incorporated, Chairman (AICE)

Prof. A. L. Hesselschwerdt, Massachusetts Institute of Technology (ASME)

Dr. Hugh M. Long, Tonawanda, New York (AIP)

Dr. Loyd B. Nesbitt, General Electric Laboratory (AIP)

Dr. David White, Ohio State University (ACS)

207
Advisory Panel to Central Radio Propagation Laboratory

Prop. Arthur H. Waynick, The Pennsylvania State University, Chairman (IEEE)

Mr. Stuart L. Bailey, Alexandria, Va. (IEEE)

Prof. Henry G. Booker, Cornell University (IEEE)

Dr. R. A. Helliwell, Stanford University (IEEE)

Dr. S. W. Herwald, Westinghouse Electric Corporation (IEEE)

Dr. F. S. Johnson, Graduate Research Center (AIP)

Dr. John M. Kelso, AGF Industries, Inc. (IEEE)

Dr. John B. Smyth, Smyth Research Associates (AIP)

Dean George Town, Iowa State University (IEEE)

Advisory Panel to Radio Standards Laboratory

Prof. Arthur A. Oliner, Polytechnic Institute of Brooklyn, Chairman

Dr. Sidney A. Bowhill, University of Illinois (IEEE)

Prof. Walter Gordy, Duke University (AIP)

Prof. E. L. Hahn, University of California (AIP)

Dr. E. W. Houghton, Bell Telephone Laboratories (IEEE)

Prof. E. C. Jordan, University of Illinois (IEEE)

Dr. R. Kompfner, Bell Telephone Laboratories (IEEE)

Prof. W. A. Lewis, Illinois Institute of Technology (IEEE)

Prof. N. F. Ramsey, Harvard University (AIP)

Dr. John C. Simons, National Research Corporation (IEEE)

ADVISORY COMMITTEE ON ENGINEERING AND RELATED

STANDARDS

(Members are nominated by the American Standards Association (ASA) and the American Society for Testing and Materials ( ASTM)

Mr. W. A. Wildhack, National Bureau of Standards, Chairman

Mr. Roger E. Gay, American Standards Association (ASA)

Mr. Richard T. Kropf, Belding Heminway Company (ASTM)

Mr. John W. McNair, American Standards Association (ASA)

Mr. N. L. Mochel, Westinghouse Electric Corporation (ASTM)

Mr. Frank H. Roby, American Standards Association (ASA)

Mr. Alfred C. Webber, E. I. du Pont de Nemours, Inc. (ASTM)

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 Standards, Chairman

Mr. Joseph M. Aldrich, San Diego, California Dr. William G. Amey, Leeds & Northrup Company

Mr. Ivan G. Easton, General Radio Company

Mr. Charles E. Johnson, The Boeing Company

Mr. Sheldon C. Richardson, General Electric Company

Dr. George Sonneman, American Optical Company

Mr. Bruno Weinschel, Weinschel Engineering

Mr. Charles E. White, Avco Research & Advanced Development Division

Mr. L. B. Wilson, Sperry Gyroscope Company

WEIGHTS AND MEASURES ADVISORY COMMITTEE

(Members are nominated by the National Conference on Weights and Measures)

Mr. W. S. Bussey, National Bureau of Standards, Chairman

Miss Genevieve Blatt, Secretary of Internal Affairs, Commonwealth of Pennsylvania

Mr. John Hoyt Chaloud, Ivorydale Technical Center Mr. C. G. Gehringer, Howe-Richardson Corporation

Prof. L. J. Gordon, Weights and Measures Research Center, Denison University

Mr. Rollin E. Meek, State Board of Health, Indiana

Mr. Donald Malcolm Turnbull, City of Seattle, Comptrollers Department

208
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 1963.

RECIPIENT

Bass, Arnold M.

Bowles, Kenneth L. Carrincton, Tucker

Carter, Thomas J. Craig, Norman

Davis, Philip J. Hammond, Harry K., Ill Jackson, Julius L. Jacox, Marilyn E. Mandel, John

McIntyre, Donald

McPherson, Archibald T.

Meggers, William Newman, Sanford B. Paffenbarcer, George C. Parsons, Douclas E.

Penner, Samuel

Rosenberg, Samuel J. Schiefer, Herbert F. Scribner, Bourdon F.

Sweeney, William T. Taylor, Lauriston S. Wexler, Arnold

Yakowitz, Harvey

Joint Awards

Ambler, Ernest Haywakd, Raymond W.

Hoppes, Dale D. Hudson, Ralph P. (Wu, Chien Shiung, Columbia

University) Myerson, Melvin R. Net, Wilbert R. Young, Theodore R.

AWARD

Elected Fellow of Optical Society of America RESA Boulder Scientist Award

Silver Medal of the Combustion Institute Benedict College Award for Outstanding Achievement

William Blum Award of the Electrochemical Society Chauvenet Prize of the Mathematical Association of America Award of Merit by American Society for Testing and Materials Fulbright Scholarship

Utica College Award for Outstanding Achievement

Elected Fellow of the American Association for the Advancement

of Science

National Capital Award by D.C. Council of Engineering and Architectural Societies Outstanding Service Award From the Standards Engineers Society and

the American Society for Testing and Materials Achievement Award of the Spectroscopy Society of Pittsburgh Elected Fellow of the Royal Microscopical Society Achievement Medal from Alpha Omega Fraternity Walter C. Voss Award of the American Society for Testing and

Materials Fellowship from the John Simon Guggenheim Memorial Foundation

Burgess Memorial Award from American Society for Metals Honorary Doctor of Science Degree from Ferris Institute Elected Honorary Member of Groupement pour I'Advancement Methodes

Spectrographiques Annual Award of American Academy for Plastics Research in Dentistry Orator of the Year of Radiological Society of North America

Elected Fellow of the Instrument Society of America Award for Prize Photograph submitted to World Metals Congress of American Society for Metals

John Price Wetherill Medal from Franklin Institute

Charles B. Dudley Medal from American Society for Testing and

Materials

HIGHEST NATIONAL BUREAU OF STANDARDS AWARD

RECIPIENT

Wait, James R. Joint Award:

Bender, Peter L. Driscoll, Raymond L.

AWARD

Samuel Wesley Stratton Award

Samuel Wesley Stratton Award

DEPARTMENT OF COMMERCE EXCEPTIONAL SERVICE AWARDS

RECIPIENT

Brenner, Abner

Cameron, Joseph

Frederikse, Hans P. R. Thomas, Richard N.

TECHNICAL AREA

Electroplating Modern statistical and computational methods

Solid state physics Atmospheres of stars

209
DEPARTMENT OF COMMERCE MERITORIOUS SERVICE AWARDS

RECIPIENT

Bean, Hhadioru H. Beaity, Koukht W.

Block, Stanley

Bussey, Howard E.

Corliss, Charles H. HlLSENHATH, JOSEPH

Loving, Vernon W.

Mears, Thomas W.

Pincock, Glen

Radfoii», Hahhison E. Richmond, Joseph C. Spinner, Sam

Stiehler, Robert D. Swanson, Howard E. Woolley, H aiiold W.

Joint Award

Pruitt, John S.

Domen, Steve R.

TECHNICAL AREA

associated with the interaction of elecRadio wave refraction Microwave circuit standards

Analysis of crystal structures Electromagnetic parameters

tromagnetic waves

Quantitative spectroscopy and astrophysics Conception and development of OMNITAB

Instrument craftKinanship Standard reference materials Health of NBS staff Molecular energy levels and chemical kinetics Thermal radiation measurements Dynamic elastic properties Standardization of rubher and rubber products Standard x-ray diffraction powder patterns Thermodynamic properties of gases

Standards for determination of total energy content of high energy

x-ray beams

3.6. EDUCATION AND TRAINING PROGRAM

Available to all staff members at the Bureau is a broad employee development program which is implemented primarily through both the NBS Graduate School and nongovernment educational and training facilities. The

program covers educational levels through postdoctoral research. The program is offered at both the Boulder and Washington Laboratories; its primary objectives are the increase of efficiency in the conduct of official assigned duties and the systematic preparation for increased responsibilities.

The Graduate School curriculum includes graduate and undergraduate

courses in the physical sciences, mathematics, and certain branches of

engineering. Also, a series of scientific colloquia and seminars are led by

research leaders from the Bureau staff and from other research centers. In

addition, general staff development courses, such as scientific German, practical metallurgy, and mathematical symbolism and terminology, are also

offered. Educational counseling is available and employees may receive

thesis accreditation for research done at the Bureau.

Since the educational requirements of staff members are varied and

changing, the NBS Educational Committee determines course offerings on

the basis of periodic need surveys. The program is flexible, including both

NBS in-hours courses and NBS-university-sponsored out-of-hours courses. The Technician Career Program, established in 1960, offers a series of

in-hours courses on the fundamentals of science and mathematics. The

Program helps increase job efficiency and offers educational opportunities

to subprofessional laboratory personnel. A workshop in correspondence

management, one in filing, and a telephone training course was offered during 1963. Since the establishment of the Washington educational program

in 1908, 42 universities have awarded 293 graduate degrees based partly on credits obtained or thesis work carried on under the NBS Graduate

School Program.

The Bureau has expanded the Graduate Program at Boulder through the

establishment of a Joint-Course program and an Adjoint Professor plan with

210
the University of Colorado. Various graduate departments at both the NBS

Graduate School and the University offer courses simultaneously, with

benefits to both the Government and the University. Bureau staff members

who teach the courses have the title of Adjoint Professor at the University.

During the summer of 1963, an intensive three-week course in Electromagnetic Measurements and Standards was offered at Boulder in cooperation with the University of Colorado. Participants in the course included

not only NBS staff members, but also employees from other government

agencies, industry, universities, and foreign research laboratories.

Nongovernment training, authorized by the Government Employees Training Act of 1958, falls into three major categories. These are:

1. Full-time (3 to 12 months) postdoctoral study and research assignments 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 institutions,

generally in early evening classes.

Approximately 425 staff members at Washington and Boulder were trained

through nongovernment facilities in 1963; fourteen career scientists were

selected for full-time research assignments at universities and research centers. Participants in approved full-time nongovernment training programs

receive full salary and expenses, including tuition, related fees, travel, and

per diem, as well as transportation of family and household effects. Short concentrated courses and training programs at universities and in

industry were attended by forty-six Washington staff members. One hundred

thirty-nine Washington employees, mostly from technical divisions, attended

job-related courses at local educational facilities. The Bureau sponsors a student trainee summer program for college stu- dents majoring in the physical sciences, mathematics, and certain branches

of engineering. Each summer an integrated work-study program including

lectures, tours, demonstrations, supervised laboratory assignments, and professional counseling, is conducted. The program acquaints young people

interested in career scientific research opportunities with the work being

done at NBS. One of the purposes of the program is to help in preparing

talented students for scientific careers. The enrollment in the 1963 student

program was two hundred thirty-nine students, which included eleven high

school students who were winners in the Westinghouse Science Talent Search

or other national science contests. The students participating in the program

came from schools throughout the country; many of the participants in the

program were graduate students. In collaboration with the National Research Council, the Graduate School

offers postdoctoral resident research associateships to young scientific investigators of unusual ability and promise of becoming creative leaders in basic

research in the various branches of the physical and mathematical sciences.

211
While acquiring basic knowledge, they have opportunities to develop new

scientific approaches and laboratory skills, and thus advance scientific knowledge. Twenty new Research Associateships (tenable at both the Washington and Boulder Laboratories) are open each year. During 1963, the

following young men were selected and served: Stanley Abramowitz, Robert

L. Brown, Halbert H. Carmichael, George E. Chamberlain, Richard F. Demar, James E. Faller, Marcel L. Halberstadt, Eugene C. Johnsen, Robert

H. Kastl, David M. Larsen, Joseph A. Pirog, Duncan E. Poland, Albert

Romano, Joe D. Simmons, Robert E. Simpson, John W. Stewart, Tannie

Stovall, Joseph L. Thompson and George H. Thomson.

Scientific staff meetings, held weekly 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 program. They are open to all professional staff members of

the Bureau and to scientific personnel from neighboring laboratories.

3.7. 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. Annual subscription: Domestic,

$4; foreign, |4.75. Single copy, 70 cents. B. Mathematics and Mathematical Physics, issued quarterly. Annual subscription:

Domestic, $2.25; foreign, $2.75. Single copy, 75 cents. C. Engineering and Instrumentation, issued quarterly. Annual subscription: Domestic, $2.25; foreign, $2.75. Single copy, 75 cents. **D. Radio Propagation, issued six times a year. Single copy, 75 cents. The papers listed below have appeared in the four-section Journal since June 1962.

Volume 66A (Phys. and Chem.), No. 4 (July-Aug. 1962)

Dielectric properties of semicrystalline polychlorotrifluoroethylene. A. H. Scott, D. J. Scheiber, A. J. Curtis, J. I. Lauritzen, Jr., and J. D. Hoffman.

Thermal degradation of fractionated high and low molecular weight polystyrenes. S. L. Madorsky, D. Mclntyre, J. H. O'Mara, and S. Straus. Synthesis of 2-propoxy-5-methylbenzoic acid. G. M. Brauer and L. Simon.

The gamma-ray distribution from oriented cerium-141. J. F. Schooley, D. D. Hoppes,

and A. T. Hirshfeld.

Light source for producing self-reversed spectral lines. J. Sugar.

A diamond cell for X-ray diffraction studies at high pressures. G. J. Piermarini and

C. E. Weir.

Thermal conductivity of gases. I. The coaxial cylinder cell. L. A. Guildner.

Thermal conductivity of gases. II. Thermal conductivity of carbon dioxide near the

critical point. L. A. Guildner.

Derivation of the relaxation spectrum representation of the mechanical response function. R. S. Marvin.

Intermediate phases in superconducting niobium-tin alloys. L. L. Wyman, J. R. Cuthill G. A. Moore, J. J. Park, and H. Yakowitz.

*Publications for which a price is indicated are available by purchase from the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402 (foreign postage, one-fourth additional). Reprints from outside journals and the NBS Journal of Research may often be obtained directly from the authors.

** Changed to Radio Science in January 1964, issued monthly. Annual subscription : Domestic, S9

foreign, $11.50. Single copy, S1.00.

212
Volume 66A (Phys. and Chem.), No. 5 (Sept.-Oct. 1962)

Calorimetric calibration of an ionization chamber for determination of X-ray total beam

energy. J. S. Pruitt and S. R. Domen.

Zinc oxide as a standard substance in the solution calorimetry of portland cement.

E. S. Newman.

Nuclear optical model analysis of neutron elastic scattering for calcium. R. S. Caswell.

Pyrolysis of some polyvinyl polymers at temperatures up to 1,200 °C. S. Straus and

S. L. Madorsky.

Lattice frequencies and rotational barriers for inorganic carbonates and nitrates from

low temperature infrared spectroscopy. R. A. Schroeder, C. E. Weir, and E. R.

Lippincott.

Foreign gas broadening of the lines of hydrogen chloride and carbon monoxide. E. K.

Plyler and R. J. Thibault.

Monolayers of adipate polyesters at air-liquid interfaces. W. M. Lee, R. S. Stromberg,

and J. L. Shereshefsky.

Volume 66A (Phys. and Chem.), No. 6 (Nov.-Dec. 1962)

Heat of formation of nitronium perchlorate. A. A. Gilliland. Phase equilibrium relations in the binary system bismuth sesquioxide-niobium pentoxide

R. S. Roth and J. L. Waring.

Elastic constants of rutile (TiO=). J. B. Wachtman, Jr., W. E. Tefft, and D. G. Lam, Jr. Reaction of hardened Portland cement paste with carbon dioxide. C. M. Hunt and L. A. Tomes.

Titanium standards for hydrogen content. J. T. Sterling, F. J. Palumbo, and L. L. Wyman.

Ultraviolet stability of crosslinked polycaprolactam systems. S. D. Bruck.

Spectral-line intensities and g/-values in the first spectrum of copper. C. H. Corliss. Batch adsorption from solution. W. V. Loebenstein.

Separation of hafnium from zirconium and their determination: separation by anionexchange. L. A. Machlan and J. L. Hague.

Volume 67A (Phys. and Chem.), No. 1 (Jan.-Feb. 1963)

Heat of formation of calcium aluminate monosulfate at 25 °C. H. A. Berman and

E. S. Newman.

2,3-Dimethylpentane and 2-methylhexane as a test mixture for evaluating highly efficient fractionating columns. E. C. Kuehner.

Phase equilibrium relations in the Sc203-Ga203 system. S. J. Schneider and J. L. Waring.

Analysis of two infrared bands of CH2 D2 . W. B. Olson, H. C. Allen, Jr., and E. K. Plyler.

Precise coulometric titrations of halides. G. Marinenko and J. K. Taylor.

Radial distribution study of vitreous barium borosilicate. G. J. Piermarini and S. Block. Dynamic compressibility of poly (vinyl acetate) and its relation to free volume. J. E. McKinney and H. Vera Belcher. An investigation of the constitution of the mercury-tin system. D. F. Taylor and C. L. Burns.

Effect of methyl bromide additions on the flame speed of methane. C. Halpern.

Volume 67A (Phys. and Chem.), No. 2 (Mar.-Apr. 1963)

Third spectrum of palladium (Pd in) . A. G. Shenstone.

Broadening of the rotational lines of carbon monoxide by HC1 and by argon. R. J. Thibault, J. H. Jaffe, and E. K. Plyler.

Theory of frustrated total reflection involving metallic surfaces. T. R. Young and B. D.

Rothrock.

Quantitative metallography with a digital computer: application to a Nb-Sn super- conducting wire. G. A. Moore and L. L. Wyman.

Moire fringes produced by a point projection X-ray microscope. S. B. Newman.

Cyclic polyhydroxy ketones. I. Oxidation products of hexahydroxybenzene (benzenehexol) . A. J. Fatiadi, H. S. Isbell, and W. F. Sager.

Effect of pressure and temperature on the refractive indices of benzene, carbon tetra- chloride, and water. R. M. Waxier and C. E. Weir.

Pressure-density-temperature relations of fluid para hydrogen from 15 to 100 "K at pressures to 350 atmospheres. R. D. Goodwin, D. E. Diller, Hans M. Roder, and L. A. Weber.

A method for determining the elastic constants of a cubic crystal from velocity meas- urements in a single arbitrary direction; application to SrTi03 . J. B. Wachtman, Jr., M. L. Wheat and S. Marzullo.

213
Volume 67 A (Phys. ond Chem.), No. 3 (May-June 1963)

An absolute calibration of t he National Bureau of Standards Thermal Neutron Flux.

E. J. Axton. Absorption bands of carbon dioxide from 5.3 to 4.6 microns. Arthur G. Maki, Earle K. Plyler, and Robert J. Thibault. Infrared spectrum of the VrVt band of C'C^He. Walter J. Lafferty and Karl K. Plyler.

Self-broadening of carbon monoxide in the 2v and 3u bands. Earle K. Plyler and

Robert J. Thibault.

Thermodynamic properties of polyethylene predicted from paraffin data. Martin G. Broadhurst.

Spectrophotometry determination of the thermodynamic pK value of picric acid in water at 25 °C. Marion Maclean Davis and Maya Paabo.

Purity analysis of highly purified materials by time-temperature cryometry. Gaylon S. Ross and Herbert D. Dixon.

Synthesis of isomers of eugenol. Gerhard M. Brauer, Richard Warren Morris, and

Williard B. Howe.

Analysis of families of curves. John Mandel and Frank L. McCrackin.

A controlled atmosphere chamber. Charles L. Gordon and Rolf B. Johannesen.

Volume 66B (Math, and Math. PhyB.), No. 3 (July-Sept. 1962)

The first run preceded by a quota. A. J. Goldman and B. K. Bender.

Two theorems on matrices. M. Newman.

Mill's ratio for multivariate normal distributions. I. R. Savage.

Angle as a fourth fundamental quantity. J. E. Romain.

Invalidity of Meixner's theorem in irreversible thermodynamics. R. E. Nettleton. Selected bibliography of statistical literature, 1930 to 1957: VI. Theory of estimation

and testing of hypotheses, sampling distributions, and theory of sample surveys. L. S. Deming.

Volume 66B (Math, and Math. Phys.), No. 4 (Oct.-Dec. 1962)

Reliability of a system in which spare parts deteriorate in storage. G. H. Weiss.

Estimation of dispersion parameters. W. A. Thompson, Jr. Laguerre expansions for successive generations of a renewal process. G. H. Weiss.

Bounds on ratios of means. G. T. Cargo and O. Shisha.

A model for the viscoelastic behavior of rubberlike polymers including entanglement

effects. R. S. Marvin and H. Oser. Black box maximization of circular coverage. C. T. Zahn, Jr. An application of information theory to the analysis of contingency tables, with a table of 2n In 7i, n= 1 ( 1 ) 10,000. S. Kullback, M. Kupperman, and H. H. Ku.

Volume 67B (Math, and Math. Phys.), No. 1 (Jan.-Mar. 1963)

Evaluation of a generalized elliptic-type integral. L. F. Epstein and J. H. Hubbell.

An algorithm for obtaining an orthogonal set of individual degrees of freedom for

error. J. M. Cameron.

Recognition of completely mixed games. A. J. Goldman.

A new type of computable inductor. C. H. Page.

Numerical computation of the temporal development of currents in a gas discharge

tube. W. Borsch-Supan and H. Oser. Tables of genera of groups of linear fractional transformations. H. Fell, M. Newman,

and E. Ordman.

Volume 67B (Math, and Math. Phys.), No. 2 (Apr.-June 1963)

Maximum cellular Boolean functions and perfect Gray codes. A. J. Goldman and B. K.

Bender.

The meaning of Betti's reciprocal theorem. C. Truesdell.

Effect of molecular weight on viscoelastic properties of polymers as predicted by a molecular theory. H. Oser and R. S. Marvin.

Selected bibliography of statistical literature: supplement, 1958-1960. L. S. Deming.

Volume 66C (Eng. and Instr.), No. 3 (July-Sept. 1962)

Measurement of longitudinal spherical aberration in the extra-axial region of lenses.

F. E. Washer and W. R. Darling.

Spark-gap flashover measurements for steeply rising voltage impulses. J. H. Park and

H. N. Cones.

Evaporated-film electric hygrometer elements. F. E. Jones.

214
Methods of measuring the resistivities of anisotropic conducting media in situ. S. Rush.

Corrosion of steel pilings in soils. M. Romanoff.

Corrosion rates of ferrous alloys (Fe-Cr and Fe-Cr-Si) measured by polarization tech- nique. W. J. Schwerdtfeger.

A furnace for thermocouple calibrations to 2,200 C C. D. B. Thomas.

Total hemispherical emittance of coated and uncoated Inconel and types 321 and 430

stainless steel. J. C. Richmond and W. N. Harrison.

"Mail Separator" control computer preliminary logical design. S. Henig and E. C. Palasky.

Method of measuring emissivities of metals in the infrared. A. G. Maki and E. K.

Plyler.

Volume 66C (Eng. and Instr.), No. 4 (Oct.-Dec. 1962)

An ultra-high speed image dissecting camera for photographing strong shock waves. K. B. Earnshaw and C. M. Benedict.

Biprism method of determining the equivalent focal length of flat field lenses. W. R.

Darling.

Effect of air drag on the motion of a filament struck transversely by a high-speed

projectile. F. L. McCrackin.

A precision noise spectral density comparator. C. M. Allred. Stresses in a plate uniformly compressed over portions of its two opposite edges. M. Chi

and W. D. Kroll. Studies of the stress-corrosion cracking of low-carbon steels. H. L. Logan.

A dual centrifuge for generating low-frequency sinusoidal accelerations. R. O. Smith,

E. A. Willis, and J. S. Hilten. Rotational micromanometers. K. Lofquist.

Study of gypsum plasters exposed to fire. J. V. Ryan.

Volume 67C (Eng. and Instr.), No; 1 (Jan.-Mar. 1963)

Method for calibrating a standard volt box. B. L. Dunfee.

Stability of residual thiosulfate in processed microfilm. C. I. Pope.

Equipment for single crystal growth from aqueous solution. J. L. Torgesen, A. T. Horton, and C. P. Saylor.

An automatic multichannel correlator. R. F. Brown, Jr. Elastic constant—porosity relations for polycrystalline thoria. S. Spinner, F. P. Knudsen, and L. Stone. An oxygen partial pressure warning instrument. L. Greenspan.

New fast-opening, large-aperture shutter for high-speed photography. E. C. Cassidy

and D. H. Tsai. Equations for the radiofrequency magnetic permeameter. C. A. Hoer and A. L. Rasmussen.

Volume 67C (Eng. and Instr.), No; 2 (Apr.—June 1963)

Temperature dependence of the elastic constants of thoria specimens of varying porosity.

S. Spinner, L. Stone, and F. P. Knudsen.

Residual stresses and their relaxation on the surfaces of sections cut from plastically

deformed steel specimens. Clarence J. Newton.

Permeation rates of electrolytic hydrogen and deuterium through iron. Joseph W. Pitts. Steady state heat conduction in cylinders with multiple continuous line heat sources. B. A. Peavy.

A radial-flow apparatus for determining the thermal conductivity of loose-fill insula- tions to high temperatures. D. R. Flynn.

Analysis of a microwave radiometer for precise standardization of noise sources. Gray

D. Ward and John M. Richardson.

Realistic evaluation of the precision and accuracy of instrument calibration systems.

Churchill Eisenhart.

Volume 66D (Radio Prop.), No. 4 (July-Aug. 1962)

Propagation problems with space radio communications. K. Rawer. On the absolute intensity of incoherent scatter echoes from the ionosphere. K. L. Bowles,

G. R. Ochs, and J. L. Green. On the forward scattering of radio waves in the lower ionosphere. T. Hagfors.

Representation of diurnal and geographic variations of ionospheric data by numerical

methods. W. B. Jones and R. M. Gallet. Interaction between an obliquely incident plane electromagnetic wave and an electron beam in the presence of a static magnetic field of arbitrary strength. K. H. B. Wilhelmsson.

714-691 0—64 15 215
An analysis of VLF mode propagation for a variable ionospheric height. J. R. Wait.

A method for the determination of lower ionosphere properties by means of field meas- urements on sferies. F. B. Harris, Jr., and R. L. Tanner. Defocusing of radio rays by the troposphere. R. E. Wilkerson.

Magnetotelluric fields in the frequency range 0.03 to 7 cycles per kilosecond: Part I. Power spectra. C. W. Morton and A. A. J. Hoffman.

Magnetotelluric fields in the frequency range 0.03 to 7 cycles per kilosecond: Part II. Geophysical interpretation. C. W. Horton and A. A. J. Hoffman.

Impedance of a circular loop in an infinite conducting medium. M. B. Kraichman.

Volume 66D (Radio Prop.), No. 5 (Sept.-Oct. 1962)

Theory of magneto-telluric fields. J. R. Wait

Propagation characteristics of magneto-ionic plasma columns. D. Formato and A.

Gilardini. Dielectric loading of electric dipole antennas. J. Galejs.

Possible influence of the ionosphere on the impedance of a ground-based antenna. J. R.

„ Wait ' Some statistical theory for the analysis of radio propagation data. M. M. Siddiqui.

Auroral sporadic-/? ionization. R. D. Hunsuckerand L. Owren.

Comparative study of the correlation of seasonal and diurnal cycles of transhorizon radio

transmission loss and surface refractivity. B. R. Bean, L. Fehlhaber and J. Grosskopf.

Enhancement of the lunar tide in the noon critical frequency of the F% layer over the magnetic equator. R. G. Rastogi.

Scattering from a conducting sphere embedded in a semi-infinite dissipative medium.

J. Galejs.

High-frequency scattering from a coated sphere. V. H. Weston and R. Hemenger.

Propagation of spherical waves through an ionosphere containing anisotropic irregularities. K. C. Yeh.

Volume 66D (Radio Prop.), No. 6, (Nov.-Dec. 1962)

RF impedence probe measurements of ionospheric electron densities. J. A. Kane, J. E. Jackson, and H. A. Whale.

Methods for applying numerical maps of ionospheric characteristics. W. B. Jones and

R. M. Gallet. Very-low-frequency radio propagation in the ionosphere. D. W. Swift. Prolonged space-wave fadeouts in tropospheric propagation. A. P. Barsis and M. E. Johnson.

Range-error compensation for a troposphere with exponentially varying refractivity.

J. J. Freeman.

On the geometrical optics of curved surfaces with periodic impedance properties. C. J. Marcinkowski and L. B. Felsen. On the limitations of geometrical optics solutions for curved surfaces with variable im- pedance properties. C. J. Marcinkowski and L. B. Felsen. Conversion of the amplitude-probability distribution function for atmospheric radio

noise from one bandwidth to another. A. D. Spaulding, C. J. Roubique, and W. Q.

Crichlow.

Some statistical properties of pulsed oblique HF ionospheric transmissions. M. Balser and W. B. Smith.

Induction in a small loop moving with a magnetostatic dipole toward a conducting half

space. M. B. Kraichman.

Propagation of terrestrial radio waves of long wavelength—theory of zonal harmonics

with improved summation techniques. J. R. Johler and L. A. Berry.

Terminal-zone corrections for a dipole driven by a two-wire line. K. Iizuka and R. W. P. King.

Pattern synthesis with a flush-mounted leaky-wave antenna on a conducting circular

cylinder. A. Ishimaru and F. R. Beich.

Volume 67D (Radio Prop.), No. 1 (Jan.-Feb. 1963)

"A lunar theory reasserted"—a rebuttal. J. V. Evans.

Point-to-point communication on the moon. L. E. Vogler.

HF communication during ionospheric storms. G. E. Hill. Use of surface refractivity in the empirical prediction of total atmospheric refraction. W. R. Iliff and J. M. Holt.

Effective sunspot numbers, January 1961 through July 1962. W. B. Chadwick.

On the theory of radio wave propagation over inhomogenous earth. K. Furutsu.

216
Correction to "Fields of electric dipoles in sea water, the earth-atomsphere-ionosphere

problem". W. L. Anderson.

Composition of reflection and transmission formulae. J. Heading.

Titheridge coefficients for the polynomial method of deducing electron density profiles

from ionograms. A. R. Long and J. O. Thomas.

Input admittance of linear antennas driven from a coaxial line. T. T. Wu.

Volume 67D (Radio Prop.), No. 2 ( Mar.-Apr. 1963)

The protection of frequencies for radio astronomy. R. L. Smith-Rose.

Radar reflections from the moon at 425 Mc/s. G. H. Millman and F. L. Rose. Sunset and sunrise in the ionosphere: effects on the propagation of longwaves. J. Rieker.

Correction of atmospheric refraction errors in radio height finding. W. B. Sweezey and

B. R. Bean. Empirical determination of total atmospheric refraction at centimeter wavelengths by

radiometric means. A. C. Anway.

Propagation of radiofrequency electromagnetic fields in geological conductors. V. Fritsch. Translated from German by A. P. Barsis. WWV reception in the arctic during ionospheric disturbances. G. E. Hill and John R. Herman.

Height-gain for VLF radio waves. J. R. Wait and K. P. Spies.

Perturbation method in a problem of waveguide theory. D. Fox and W. Magnus.

Some wave functions and potential functions pertaining to spherically stratified media.

C. T. Tai. Radiation from a plasma-clad axially-slotted cylinder. W. V. T. Rusch.

Two- and three-loop superdirective receiving antennas. E. W. Seeley. Hallen's method in the problem of a cavity-back rectangular slot antenna. J. Galejs.

Relative convergence of the solution of a doubly infinite set of equations. R. Mittra.

Volume 67B (Radio Prop.), No. 3 (May-June 1963)

Effects of radio wave propagation through mid-latitude 6300 A auroral arcs. J. R. Roach.

Comparison of observed atmospheric radio refraction effects with values predicted

through the use of surface weather observations. B. R. Bean and G. D. Thayer.

Ionospheric scattering effects in long-distance propagation. H. A. Whale.

Concerning solutions of the VLF mode problem for an anisotropic curved ionosphere.

James R. Wait.

On the statistical theory of electromagnetic waves in a fluctuating medium (I). K. Furutsu. Reception of skywave signals near a coastline. J. Bach Andersen.

Analysis and synthesis of nonuniform transmission lines or stratified layers. G. Latmiral,

G. Franceschetti, and R. Vinciguerra. Resonant characteristics of a corrugated sphere. James R. Wait and Carolen M.

Jackson.

Impedances of long antennas in air and in dissipative media. D. W. Gooch, C. W.

Harrison, Jr., R. W. P. King, and T. T. Wu.

Reflection of VLF radio waves from an inhomogenous ionosphere. Part I. Exponentially varying isotropic model. James R. Wait and Lillie C. Walters.

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 fudamental science in which the Bureau has

represented the Nation, and 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.)

Central Radio Propagation Laboratory Ionospheric Predictions: This is a monthly

publication for those concerned 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/s are

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use. (Annual subscription: domestic, $1.50; foreign, $2.00.)

217
Monographs. These are usually contributions to the technical literature which are

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Until July 1959 most of this type of material was published in the Circular series.

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43. Chemistry of cement, Proceedings of the Fourth International Symposium, Washington 1960, Volume I. August 31, 1962, S6.50; Volume II. September 27, 1962. $6.25.

49. Tables of Einstein functions, vibrational contributions to the thermodynamic functions, J. Hilsenrath and G. G. Ziegler, July 12, 1962. $2.75.

50. Bibliography on atomic transition probabilities, B. M. Glennon and W. L. Wiese,

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51. Analysis of electric energy usage in Air Force houses equipped with air-to-air heat pumps, P. R. Achenbach, J. C. Davis, and W. T. Smith. July 13, 1962. 30 cents.

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53. Experimental transition probabilities for spectral lines of seventy elements, C. H.

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56. Systems of electrical units, F. B. Silsbee. September 20, 1962. 30 cents.

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58. Corrosion of steel pilings in soils, M. Romanoff, October 24, 1962. 20 cents.

59. Mechanical behavior of crystalline solids, Proceedings of an American Ceramic

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Miscellaneous Publications. As the name implies, this series includes material, which,

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218
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.

18-14. Quarterly radio noise data—March, April, May 1962 and corrigendum for Technical Notes 18-1 through 18-11, W. Q. Crichlow, R. T. Disney, and M. A. Jenkins.

August 9, 1962. 50 cents. 18-15. Quarterly radio noise data—June, July, August 1962, W. Q. Crichlow, R. T. Dis- ney, and M. A. Jenkins. March 1, 1963. 45 cents. 40-8. Mean electron density variations of the quiet ionosphere, No. 8—October 1959, J W. Wright, L. R. Wescott, and D. J. Brown. September 1962. 35 cents. 40-9. Mean electron density variations of the quiet ionosphere, No. 9—November 1959,

J. W. Wright, L. R. Wescott, and D. J. Brown. April 22, 1963. 35 cents. 40-10. Mean electron density variations of the quiet ionosphere, No. 10—December 1959,

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98. Synoptic radio meteorology, B. R. Bean, J. D. Horn and L. P. Riggs. October 1962. 50 cents.

99. A survey of the techniques for measuring the radio refractive index, R. E. McGavin.

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120A. A tabulation of the thermodynamic properties of normal hydrogen from low

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152. Coordinated color identifications for industry, K. L. Kelly. November 1962. 15

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155. The energy parameter B for strong blast waves, D. L. Jones. July 1962. 25 cents. 157. Information selection systems retrieving replica copies: A state-of-the-art report, T. C. Bagg and M. E. Stevens. December 31, 1961. $1.25.

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160. Emission stabilization of thermionic diode noise sources, M. W. Randall and

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162. Thermal balance of the F region of the atmosphere, D. C. Hunt. September 1962. 50 cents. 163. The construction of calorimeters for the measurement of absorbed dose, B. Petree and G. Ward. November 1962. 25 cents. 164. On plasma collision frequencies proportional to energy in the radio wave reflection and transmission process, J. R. Johler and J. D. Harper, Jr. March 1, 1963. 40 cents. 165. Fading correlation bandwidth and short-term frequency stability measurements on a high-frequency transauroral path, J. L. Auterman. October 1962. 40 cents. 166. (PB181454). An atlas of whistlers and VLF emissions, A survey of VLF spectra

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219
167. The error rates in multiple FSK systems and the signal-to-noise characteristics of KM and PCM-FS systems, H. Akima. March 25, 1963. 40 cents.

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174. Research on crystal growth and defect characterization at the National Bureau of Standards during the period July to December 1962, ed. H. S. Peiser. March 15, 1963. 25 cents.

175. Curves of ground proximity loss for dipole antennas, L. E. Vogler and J. L. Noble.

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177. Table of attenuation error as a function of vane-angle error for rotary vane at- tenuators, W. Larson. May 20, 1963. 75 cents.

178. An interpolation procedure for calculating atmospheric band absorptions from

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188. Calibration of volt-ampere converters, E. S. Williams. April 25, 1963. 20 cents.

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192. Calculations of the potential and effective diffusion constant in a polyelectrolyte

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194. National standard reference data program. Background information. June 1963. 25 cents. Publications in Outside Journals*

Achenbach, P. R., Mechanical design of protected areas, Proc. BRI Conf. Design for Nuclear Age, 992, 21^19 (1962)

Achenbach, P. R., Kusuda, T., Drapeau, F. J. J., Mathematical analysis of thermal en- vironment in underground shelters, ASHRAE Symp. Survival Shelters, pp. 9-33

(June 1962).

Agy, V., Polar blackout during the International Geophysical Year, Intern. Conf. Cosmic

Rays and the Earth Storm, Proc. Tokyo Phys. Soc. Japan 1, 121 (1962)

Ailor, W. H., Jr., Reinhart, F. M., Ten years weathering data on aluminum alloys, Ma

terials Protect. 2, No. 6, 30-36 (June 1963 )

Akima, H., The error rate in a multiple frequency shift system and the output SNR in an FM and a PCM-FS system, Conf. Digest of Intern. Conf. Satellite Communication,

London, England, pp. 305-310 (Dec. 1962)

Allen, H. C, Jr., Cross, P. C, Molecular vib-rotors, John Wiley & Sons Inc., New York,

N.Y., (1963).

Allen, H. C, Jr., Olson, W. B., Sum rules for vibrational-rotational energy levels includ- ing centrifugal distortion, J. Chem. Phys. 37, No. 2, 212-214 (July 1962).

Allen, H. C, Jr., Olson, W. B., Vibrational-rotational spectroscopy, Ann. Rev. Phys.

Chem. 13, 221-240 (1962).

Alt, F. L., Digital pattern recognition by moments. Book, Optical Character Recognition,

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(Spartan Books, Washington, D.C., 1962)

Alt, F. L., Safety levels in military inventory management, Operations Res. 10, No. 6, 786-794 (Dec. 1962).

Ambler, E., Nuclear orientation, Book, Methods of Experimental Physics 5, Sec. 2.4-2.3,

162-214 (A cademic Press Inc., New York, N.Y., 1963)

Ambler, E., Eisenstein, J., Schooley, J., Traces of products of angular momentum matrices II. Spherical basis, J. Math. Phys. 3, No. 4, 760-771 (July-Aug. 1962)

*For completeness, a few references to publications issued previous to July 1962 are included.

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Anderson, M. M., Transparent rigid mount for vacuum stopcocks, Rev. Sci. Instr. 34, No.

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Armstrong, G. T., Marantz, S., Heats of formation of two isomers of difluorodiazine, J. Chem. Phys. 38, No. 1, 169-172 (Jan. 1963)

Arnett, R. W., Millhiser, D. R., Probert, W. H., Experimental determination of the bulk density of boiling liquid oxygen, Advan. Cryog. Eng. 8, Paper E-4, 256-262

(1963).

Arp, V. D., Kropschot, R. H., Helium, Book, Applied Cryogenic Engineering, Ed. R. W.

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Arp, V. D., Kropschot, R. H., Craig, T. S., The intermediate state of some hard superconductors, Book, Superconductors, pp. 135-141 (Interscience Publ., New York, N.Y.,

1962).

Astin, A. V., Physical measurement: pilot of progress, Steel, p. 112 (July 23, 1962).

Astin, A. V., Some problems of improving accuracy of measurement, IRE Conv.. Record,

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Astin, A. V., The basis of the measuring system, Proc. IRE 50, No. 5, 614-615 (May

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Ausloos, P. J., Lias, S. G., Radiolysis of methane, J. Chem. Phys. 38, No. 9, 2207-2214

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Ausloos, P., Rebbert, R. E., Intramolecular rearrangements. V. Formation of ethylene in the photolysis of ethyl acetate from 4 to 500 °K, J. Phys. Chem. 67, No. 1, 163-167

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Axilrod, B. M., Comments on the Rosen interaction potential of two helium atoms, J. Chem. Phys. 38, No. 1, 275-277 (Jan. 1963)

Banerjee, M. K., Levinson, C. A., Meshkov, S., Calculations of energy spectra of nuclei

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Barger, R. L., Broida, H. P., Estin, A. J., Double-resonance experiment in electronically

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Barger, R. L., Broida, H. P., Estin, A. J., Radford, H. E., Optical detection of microwave

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Barsis, A. P., Barghausen, A. F., Kirby, R. S., Studies of within-the-horizon propagation

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Barsis, A. P., Norton, K. A., Rice, P. L., Predicting the performance of long distance

tropospheric communication circuits, IRE Trans. Commun. Systems CS—10, 2-22

(Mar. 1962).

Bass, A. M., Garvin, D., Analysis of the hydroxyl radical vibration-rotation spectrum be-

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Bates, R. G., Bower, V. E., The measurement of pH, Handb. Analytical Chemistry, ed. L. Meites, Sec. 11, pp. 1-14 (McGraw-Hill Book Co. Inc., New York, N.Y., 1963).

Bates, R. G., Robinson, R. A., Interpretation of pH measurements in alcohol-water sol- vents, Proc. 7th Intern. Conf. Coordination Chemistry, Stockholm, Sweden, pp. 342-

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Bates, R. G., Rosenthal, D., Standard potential of the silver-silver chloride electrode and

activity coefficients of hydrochloric acid in aqueous methanol (33.4 Wt. %) with and

without added sodium chloride at 25°, J. Phys. Chem. 67, No. 5, 1088-1090 (May

1963) . Bay, Z., Pearlstein, R. M., Search for a slow component in alpha ionization, Phys. Rev. 130, No. 1, 223-227 (Apr. 1963)

Bazley, N. W., Fox, D. W., Lower bounds to eigenvalues using operator decompositions

of the form B*B, Arch. Rat. Mech. Anal. 10, 352 (1962)

Bean, B. L., Methods for the analysis of cement, Handb. Analytical Chemistry, Sect. 13, pp. 73-75 (McGraw-Hill Book Co. Inc., New York, N.Y., Mar. 1963).

Bean, B. R., Thayer, G. D., Comments on the limits to the utilization of the refractive index at ground level as a radio-meteorological parameter, Proc. IRE 48, No. 8, 1498-1501 (Aug. 1960).

Bean, B. R., Thayer, G. D., Comparison of observed atmospheric radio refraction effects with values predicted through the use of surface weather observations (AIAA Space

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Beatty, R. W., Decibels return loss to magnitude of voltage reflection coefficient, Micro- wave Engineer's Handb. and Buyer's Guide, pp. TD-221-TD-225 (Dec. 1962).

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Beck, R. L., Douglas, T. B., Thermophysical properties of zirconium hydrides, Am. Soc. Metals 55, 1075-1076 (1962).

Becker, J., Hosier, W. R., Electron energy levels and their relationship to lattice defects

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Beehler, R. E., Atkinson, W. R., Heim, L. E., Snider, C. S., A comparison of direct and

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Trans. Instr. I—11, Nos. 3 & 4, 231-238 (Dec. 1962)

Beers, Y., Strine, G. L., The measurement of voltage by the use of the Stark effect (Intern, Conf. Precision Electromagnetic Measurements, Boulder, Colo., 1962), I HE

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Bender, P. L., Measurement of weak magnetic fields by optical pumping methods, Bull Ampere 9% Pt. II, 621-628 ( 1960)

Bennett, J. A., A simple environmental chamber for rotating beam fatigue testing machines, Mater. Res. Std. 3, No. 6, 480-482 (June 1963)

Bennett, J. A., Use of a "peek-a-boo" information retrieval technique for a personal

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Bennett, J. A., Holshouser, W. L., Utech, H. P., The importance of environment in fatigue failure of metals, Book, Fatigue of Aircraft Structures, pp. 1-18 (Pergamon

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Berger, M. J., Monte Carlo calculations of the penetration and diffusion of fast charged

particles, Book Methods in Computational Physics, ed. B. Alder, S. Fernbach, and M.

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Berman, H. A., Newman, E. S., Letter to the editor of Revue Des Materiaux (Second).

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Bernstein, B., Conditions for second order waves in hypo-elasticity, Trans. Soc. Rheol.

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Bidelman, W. P., Corliss, C. H., Identification of Ga II lines in stellar spectra, Astrophys.

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Bienenstock, A., Calculation of crystalline size distributions from X-ray line broadening,

J. Appl. Phys. 34, No. 5, 1391 (May 1963)

Bloss, R. L., Characteristics of resistance strain gages, Book, Semiconductor and Conventional Strain Gages, ed. M. Dean, III and R. D. Douglas, Ch. VIII, pp. 123-142

(Academic Press Inc., New York, N.Y., Oct. 1962).

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Bolz, L. H., Broida, H. P., Peiser, H. S., Some observations on growing crystals of argon, Acta Cryst. 15, No. 8, 810-812 (Aug. 1962).

Bolz, L. H., Mauer F. A., Measurement of the lattice constants of neon isotopes in the temperature range 4-24°K, (Proc. 11th Annual Conf. Applications of X-ray Analysis.

Denver Res. Inst., Denver, Colo.), Book, Advances in X-ray Analysis 6, 242-249

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Bond, H. E., Harvey, K. B., The decoration of dislocations in aluminum oxide, J. Appl.

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Borkowski, R. P., Ausloos, P., Gas-phase radiolysis of isobutane, J. Chem. Phys. 38,

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Borkowski, R. P., Ausloos, P., The vapor phase fluorescence and its relationship to the

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Boswarva, I. M., Howard. R. E., Lidiard, A. B., Faraday effect in semiconductors, Proc. Roy. Soc. London, A269, 125 141 (1962)

Bowen, R. L., Properties of a silica-reinforced polymer for dental restorations, J. Am.

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Bower, V. E., Bates, R. G.. Equilibrium constants of proton-transfer reactions, Handb.

Analytical Chemistry, ed. L. Meites, Sec. 1, 20-27 (McGraw-Hill Book Co., Inc., New

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Bowles, K. L., Recent radar observations of new forms of ionosphere scatter. Comm.

Intern. Sci. Radio Union Report to Natl. Acad. Sci-Natl. Res. Council on 13th Gen. Assembly, Sept. 5-15, 1960. London. England, pp. 288-295 (Natl. Acad. Sci.-Natl. Res. Council, Washington, D.C.. 1961 )

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pp. 51-77 (Pergamon Press Inc., New York, N.Y., 1962)

Boyd, G. M., The conjugacy of magnetic disturbance variations, J. Geophys. Res. 68,

No. 4, 1011-1013 (Feb. 1963).

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Boyd, M. E., An LCAO-MO-SCF study of the structure of H02 , Intern, Symp. Molecular

Structure and Spectroscopy, Sci. Council Japan B, B404-1-B404-4 (1962).

Boyle, D. R., A neuron which performs analog functions, Proc. San Diego Symp. Bio- medical Engineering, San Diego, Calif., 1, No. 1, 256-263 (June 19-21, 1962).

Boyne, H. S., Martin, W. C, Experimental determination of the frequency ratio of optical harmonics, J. Opt. Soc. Am. 52, No 8, 880-884 (Aug. 1962).

Branscomb, L. M., Steiner, B., Seaman, M. L., Electron affinity of atomic iodine, J. Chem.

Phys. 37, No. 6, 1200-1202 (Sept. 15, 1962)

Branscomb, L. M., Thomas, R. N., Laboratory astrophysics, Phys. Today 15, No. 11, 42-44, 46 (Nov. 1962).

Brauer, G. M., Simon, L., Sangermano, L., Improved zinc oxide-eugenol type cements,

J. Dental Res. 41, No. 5, 1096-1102 (Sept.-Oct. 1962)

Breckenridge, F. C, Tentative U.S. standard for colors of signal lights, Ilium. Eng. 57,

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Brenner, A., Electrodeposition of alloys. Principles and practice. Vol. I. General sur- vey, principles, and alloys of copper and of silver, and Vol. II, Practical specific

information, Academic Press Inc., New York, N.Y., 1963. Brenner, A., The speed of processes involved in electroplating, movement of solute,

attainment of steady state and formation of metal, 49th Annual Tech. Proc. Am.

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Broida, H. P., Barger, R. L., Optical absorption spectrum of carbon in solid argon

(abstract) , Bull. Am. Phys. Soc. 7, 497-498 (Aug. 1962)

Broida, H. P., Carrington, T., Rotational, vibrational, and electronic energy transfer in the fluorescepce of nitric oxide, J. Chem. Phys. 38, No. 1, 136 147 (Jan. 1963).

Brower, W. S., Fang, P. H., Dielectric constants of Cr203 crystals, Phys. Rev. 129, No. 4, 1561 (Feb. 1963).

Brown, D. W., Florin, R. E., Wall, L. A., Formation and decay of atoms and small free radicals at low temperatures, J. Phys. Chem. 66, No. 12, 2602-2612 (Dec. 1962).

Brown, D. W., Wall, L. A., Radiation induced polymerization of propylene at high

pressure, J. Phys. Chem. 67, No. 5, 1016-1019 (May 1963)

Burkley, I. B., Rebbert, R. E., The reactions of methyl radicals with aromatic compounds.

I. Toluene, ethylbenzene, and cumene, J. Phys. Chem. 67, No. 1, 168-169 (Jan. 1963).

Burley, G., The structure of hexagonal silver iodide, J. Chem. Phys. 38, No. 12, 2807-

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Burley, G., Herrin, D. W., Effect of additives on silver iodide particles exposed to light,

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Bussey, H. E., Gray, J. E., Measurement and standardization of dielectric samples,

(Intern. Conf. Precision Electromagnetic Measurements, Boulder, Colo., 1962), IRE

Trans. Instr. 1-11, Nos. 3 & 4, 162-165 (Dec. 1962)

Calvert, W., Instability of the equatorial F layer after sunset, J. Geophys, Res. 68, No. 9

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Calvert, W., Davies, K., Stiltner, E. C, Brown, J. T., Equatorial spread-F motions, Proc.

Intern. Conf. Ionosphere, July 1962, pp. 316-322 (Institute of Physics and the Physical Society, London, England, 1963)

Calvert, W., VanZandt, T. E., Knecht, R. W., Goe, G. B., Evidence for field-aligned and

ionization irregularities between 400 and 1000 km above the earth's surface, Proc.

Intern. Conf. Ionosphere, July 1962, pp. 324-329 (Institute of Physics and the Physical

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Campbell, P. G., Wright, J. R., Bowman, P. B., The effect of temperature and humidity on the oxidation of air-blown asphalts, Mater. Res. Std. 2, No. 12, 988-995 (Dec. 1962)

Candela, G. A., Mundy, R. E., Absolute magnetic susceptibilities by the Gouy and the Thorpe-Senftle methods, IRE Trans. Instr. 1-11, Nos. 3 & 4, 106-109 (Dec. 1962).

Cargo, G. T., A connection between Tauberian theorems and normal functions, Bull. Am.

Math. Soc. 68, No. 4, 400-401 (July 1962)

Cargo, G. T., Normal functions, the Montel property, and interpolation in H

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, Michigan

Math. J. 10, 141-146 (1963).

Cargo, G. T., The segmental variation of Blaschke products, Duke Math. J. 30, No. 1, 143-150 (Mar. 1963).

Carpenter, F. G., Deitz, V. R., Critical review of sugar color and turbidity measurements,

Sugar Ind. Tech. 21, Paper 65, 32-52 (1962)

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Carpenter, F. G., Deitz, V. R., Reaction of oxygen with unkilned bone char at low

temperatures (<300 °C), Proc. 7th Tech. Session on Bone Char 1961, p. 237 (Bone

Char Research Project Inc., Charlestown, Mass., 1962)

Carpenter, F. G., Deitz, V. R., Status of sugar color and turbidity measurements, J. Am.

Soc. Sugar Beet Technologist 12, 326-347 ( 1963)

Carpenter, F. G., Larry, D., Deitz, V., Ionic, interactions with sugar colorant during

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Research Project Inc., Charlestown, Mass., 1962).

Carrera, N. J., Walker, R. F., Microbalance techniques for high temperature application.

Further developments, Book, Vacuum Microbalance Techniques 3, 153-177 (Plenum

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Carrington, T., Interpretation of rate experiments with resolved quantum levels. Dis- cussions Faraday Soc. No. 33, 44-51 (1962)

Carter, T. J., Effect of outdoor exposure on some properties of chrome-retanned leather,

J. Am. Leather Chemists Assoc. 58, No. 3, 155-160 (Mar. 1963)

Casaverde, M., Giesecke, A., Cohen, R., Effects of nuclear explosion over Johnston

Island observed in Peru on July 9, 1962, J. Geophys. Res. 68, No. 9, 2603 2611 (May

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Cataland, G., Edlow, M. H., Plumb, H. H., Recent experiments on liquid helium vapor

pressure measurements from 2° to 4 °K, Book, Temperature. Its Measurement and

Control in Science and Industry 3, Pt. I, 413^117 (Reinhold Publ. Corp., New York.

N.Y., 1962).

Cataland, G., Edlow, M. H., Plumb, H. H., The determination of absolute temperatures

from sound velocity measurements, Book, Temperature, Its Measurement and Control

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1962).

Cateora, J. V., Hubbard, R. W., Phase-lock captured by tyratron ringing circuit, Elec. Design News 7, No. 3, 74-77 (Mar. 1962)

Chadwick, W. B., Variations in frequency of occurrence of sporadic E, 1949-1959, Book.

Ionospheric Sporadic E, ed. E. K. Smith and S. Matsushita, pp. 182-193 (Pergamon

Press, Inc., New York, N.Y., 1962)

Chelton, D. B., Birmingham, B. W., Dean, J. W., Solid formation in flowing cryogenic

fluids, Advan. Cryog. Eng. 8, Paper E-ll, 311-314 (1963 ). Chivers, H. J. A., The location of the irregularities responsible for ionospheric scintilla- tion of a radio source, Proc. Physics Ionosphere, London, 1962, pp. 258-266 (The

Institute of Physics and the Physical Society, London, England, 1963).

Cline, D., Infrared wavelength dependence of the total absorptivity of electroplated

silver, J. Appl. Phys. 33, 2310-2311 (July 1962)

Cohen, R., Bowles, K. L., Introduction to the International Symposium on equatorial

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Cohen, R., Bowles, K. L., The association of plane-wave electron-density irregularities

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Collett, C. T., Gas measurement and other services of the National Bureau of Standards.

Am. Gas Assoc. Preprint No. DMC-63, pp. 1-3 (1963)

Collett, L. S., Brant, A. A., Bell, W. E., Ruddock, K. A., Siegel H. 0., Wait J. R., Laboratory investigation of overvoltage, Book, Overvoltage Research and Geophysical

Applications, ed. J. R. Wait, Ch. 5, p. 50 (Pergamon Press Inc., New York, N.Y., 1959).

Comeford, J. J., Mann, D. E.. Schoen, L. J., Lide, D. R., Jr., Infrared spectrum of difluoramine, J. Chem. Phys. 38, No. 2. 461-463 (Jan. 1963).

Cook R. K., Editor, Acoustics Section 3, pp. 3-1-3-157, American Institute of Physics

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Cook, R. K., Infrasonics, McGraw-Hill Yearbook of Science and Technology, pp. 275-276

(1962).

Cook. R. K.. Radiation of sound by ocean waves. Book. The Organization Committee of the Fourth International Congress on Acoustics, Pt. I, Paper No. 043 (Copenhagen.

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Cooper, J. W., Fano, U., Prats. F., Classification of two-electron excitation levels of helium, Phys. Rev. Letters 10, No. 12, 518-521 (June 1963)

Corliss, C. H., Experimental gf-values for seventy elements, Astrophys. J. 136, No. 3. 916-934 (Nov. 1962).

Corliss, E. L. R.. Indication limit, Book, The Organization Committee of the Fourth

International Congress on Acoustics, Pt. I. Paper No. N22 (Copenhagen, Denmark.

1962).

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Corruccini, R. J., Interpolation of platinum resistance thermometers, 10° to 273.15 °K,

Book, Temperature, Its Measurement and Control in Science and Industry 3, Pt. 1, 329-

338 (Reinhold Publ. Corp., New York, N.Y., Nov. 1962).

Corruccini, R. J., Temperature measurements in cryogenic engineering, Advan. Cryog.

Eng. 8, Paper F-l, 315-333 ( 1963)

Costrell, L., Radiation detectors, Science 139, No. 3558, 899 (Mar. 8, 1963).

Costrell, L., Scattered radiation from large Csm sources, Health Phys. 8, No. 5, 491-498

(Oct. 1962).

Costrell, L., Schwebel, A., Zimmer, G. W., Portable w flow counter for the detection of a and P particles in smear samples, Health Phys. 9, No. 6, 643 (June 1963)

Coyle, T. D., Exchange processes in the reaction of boron trichloride with triethylamineboron trifluoride, Proc. Chem. Soc. London, p. 172 (1963)

Crichlow, W. Q., Editor, The measurement of characteristics of terrestrial radio noise,

URSI Spec. Rept. No. 7 (Elsevier Publ. Co., Amsterdam, The Netherlands, 1962).

Crombie, D. D., Nonreciprocity of propagation of VLF radio waves along the magnetic

equator, Proc. IEEE 51, No. 4, 617-618 (Apr. 1963)

Cullen, W. C, Appleton, W. H., Effect of insulation on the weathering of smoothsurfaced built-up roofs exposed to solar heating, Am. Roofer and Bldg. Improvement

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Culshaw, W., Richardson, J. M., Kerns, D. M., Precision millimeter wave inter- ferometry at the U.S. National Bureau of Standards, Interferometry Symp., June 9-11,

1959, Paper 4-3, 331 (National Physical Laboratory, Teddington, Middlesex, England,

1960)

Curtiss, L. F., Editor Nuclear Physics Section 8, pp. 8-1-8-327, American Institute of Physics Handb., 2d edition ( 1963)

Cutkosky, R. D., Driscoll, R. L., La conservation des unites electriques au National

Bureau of Standards, Comite Consult. D'Elec. B. I. P. M., 9th Session, October 1961. pp. 33-35 (May 1963).

Daniel, E. D., On the dependence of absorption coefficients upon the area of the absorbent material, J. Acoust. Soc. Am. 35, No. 4, 571-573 (Apr. 1963)

Davies, K., Doppler studies of the ionospheric effects of solar flares, Proc. Intern. Conf. Ionosphere, July 1962, pp. 76-83 (Institute of Physics and the Physical Society,

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Davies, K., The measurement of ionospheric drifts by means of a Doppler technique,

J. Geophys. Res. 67, No. 12, 4909-4913 (Nov. 1962)

Davis, J. C, Achenbach, P. R., Energy use and power demands in all-electric houses

equipped with air-to-air heat pumps, ASHRAE J. 4, No. 9, 87-95 (Sept. 1962).

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air-to-air heat pumps, Suppl. Bull. Intern. Inst. Refrigeration Annexe 1962-1, pp. 349-355 (Aug. 1962).

Davis, M. M., Comparison of the relative acidic strengths of the isomeric dinitrophenols

in benzene and water, J. Am. Chem. Soc. 84, No. 19, 3623-3627 (Oct. 1962).

Davis, P. J., Packing inequalities for circles, Michigan Math. J. 10, 25-31 (1963).

Davis, T. L., Doherty, R. H., Widely separated clocks with microsecond synchronization

and independent distribution systems, IRE WESCON Conv. Pt. 5, pp. 3-17 (1960).

Dean, J. W., Timmerhaus, K. D., Thermal conductivity of solid H20 and D20 at low

temperatures, Advan. Cryog. Eng. 8, Paper E-5, 263-267 (1963).

DeGregorio, J. F., Finney, J. F. Kildhal, K., Smith, E. K., Recent sporadic E experimental

work in the United States, Book, Ionospheric Sporadic E. ed. E. K. Smith and

S. Matsushita, pp. 131-142 (Pergamon Press Inc., New York, N.Y., 1962).

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Demaree, N. C, Taylor, D. F., Properties of dental amalgam made from spherical alloy

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Desch, R. F., Larson, R. E., Bolometric microwave power calibration techniques at NBS,

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Diorio, A. F., Lippincott, E. R., Mandelkern, L., Complex formation of monomeric amides

with lithium perchlorate, Nature 194, No. 4848, 1296-1297 (Sept. 29, 1962).

Diorio, A. F., Mandelkern, L., Lippincott, E. R., Polymorphism in fibrous polypeptides;

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Dise, J. R., Pitfalls in determination of the compressive strength of concrete, Mod. Concrete 26, No. 3, 48-51 (July 1962)

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Doherly, R. H., Experimental observations and theoretical calculations leading to a model

for the lower ionosphere, Proc. Intern. Conf. Ionosphere, July 1962, pp. 428-434 (Insti- tute of Physics and the Physical Society, London, England, 1963)

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Newman, N., Conrad, G. T., Jr., Discussion of errors of a recommended standard

resistor-noise test system, IRE Trans. Component Parts CP—9, No. 4, 180-192 (Dec.

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Newman, S. B., X-ray microscopy of polymers by point projection, Mod. Plastics 40,

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Newman, S. B., Wolock, I., Microscopy of color phenomena in polymer failure (Proc.

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Norton, K. A., Barrows, E. C, Thompson, M. C, Jr., Janes, H. B., Variance of radio

frequency caused by atmospheric turbulence in line-of-sight transmissions, IRE Trans.

Instr. 1-11, Nos. 3 and 4, 153-155 (Dec. 1962)

Norton, R. B., VanZandt, T. E., Denison, J. S., A model of the atmosphere and ionosphere

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Book, Ionospheric Sporadic E, ed. E. K. "Smith and S. Matsushita, pp. 143-148

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Ogburn, F., Technology of electrodeposition, Plating 49, No. 8, 850 (Aug. 1962).

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Paffenbarger, G. C, Horizons in dentistry, Frontiers of Dental Sci. pp. 122-128 (National

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Parks, E. J., Linnig, F. J., Natural and synthetic rubbers, Anal. Chem. 35, No. 5, 160R178R (Apr. 1963).

Parks, E. J., Milliken, L. T., Linnig, F. J., Color tests for antioxidants, Rubber Age 92,

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Parthasarathy, R., Lerfald, G. M., Little, C. G., Derivation of electron density profiles in the lower ionosphere using radio absorption measurements at multiple frequencies,

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Passaglia, E., Kevorkian, H. K., The heat capacity of linear and branched polyethylene,

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Pecker, J. C, Thomas, R. N., Questions of general background and methodology relating

to aerodynamic phenomena in stellar atmospheres, II Nuovo Cimento Suppl. 22, No. X,

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Pecker, C, Thomas, R. N., Radiation transfer problems in the rocket ultra-violet lines,

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Phillips, C. W., Contribution to chapter on Trucks and Trailers in book, ASHRA Guide

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Plyler, E. K., Tidwell, E. D., Benedict, W. S., Absorption bands of carbon dioxide from

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Plyler, E. K., Tidwell, E. D., Wiggins, T. A., Rotation-vibration constants of acetylene,

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Pollack, G. L., Broida, H. P., Spectroscopic absorption of NO in crystalline and liquid

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Pope, J. H., A high-latitude investigation of the natural very-low-frequency electromagnetic radiation known as chorus, J. Geophys. Res. 68, No. 1, 83-99 (Jan. 1963).

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Powell, F. J., Contribution to chapter on Thermal Insulation in hook, ASHRAE Guide

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Powell, R. L., Caywood, L. P., Jr., Bunch, M. D., Low-temperature thermocouples, Book,

Temperature, Its Measurement and Control in Science and Industry 3, Pt. 2, 65-77

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Radford, H. E., Broida, H. P., Rotational perturbations in CN. I. Zero-field theory,

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Rebbert, R. E., Ausloos, P, The photolysis and radiolysis of CH3N2CH3 and CH3N-CH3-

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Redd, J., Carpenter, F. G., Behavior of revivified char in storage, Proc. 7th Tech. Session on Bone Char 1961, p. 223 (Bone Char Research Project, Inc., Charlestown, Mass.,

1962) . Reed, R. P., The spontaneous martensitic transformation in 18% Cr, 8% Ni steels, Acta Met. 10, 865-877 (Sept. 1962)

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Richardson, J. M., Beehler, R. E., Mockler, R. C, Fey, R. L., Atomic frequency standards

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Robertson, A. F., Burning behavior of building finish materials: two test methods, Spec.

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Rodriguez, M. S., Dickson, G., Some tensile properties of amalgams, J. Dental Res. 41,

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Rosenblatt, D., Studies of errors in economic statistics, 1962 Proc. Business and Economic

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Rosenstock, H. M., Krauss, M., Quasi-equilibrium theory of mass spectra, Book, Mass

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Rouse, G. F., Work function and secondary emission, American Institute of Physics

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Ruegg, F. W., Dorsey, W. W., Unstable detonation near a hypervelocity missile, Ninth

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Ruthberg, S., Barnes, M. W., Noyce, R. H., Alteration of the Muscovite absorption

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Salaman, R. K., A new ionospheric multipath reduction factor (MRF), IRE Trans. Commun. Systems CS-10, No. 2, 221-222 (June 1962).

Samson, C. A., Radio noise anomalies in August 1958, J. Geophys. Res. 68, 2719-2726

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Sandoval, I. B., Ausloos, P. J., Radiolysis of propane-ds in the presence of organic

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Schaffer, R., Cohen, A., D-gluco-L-glycero-3-octulose, a crystalline ketose from D-erythrose,

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Schaffer, R., Isbell, H. S., Aldonic acids. From aldoses by hypoiodite oxidation: calcium

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Schuhmann, S., Study of Knudsen's method of pressure division as a means of calibrating vacuum gages, Trans. Ninth Natl. Vacuum Symp., 1962, American Vacuum Society,

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Schulze, D. W., Foote, W. J., An adjustable instrumentation bench for Physical Laboratories, Rev. Sci. Instr. Notes 33, No. 12, 1467 (Dec. 1962)

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Shapley, A. H., Summary report on activities of spacewarn network, CORPAR Info. Bull. No. 13, pp. 17-21 (Jan. 1963).

Shapley, A. H., Lincoln, J. V., Calendar record for the International Geophysical co- operation 1959, Ann. IGY XVI, Pt. Ill, 192 (Pergamon Press Inc., New York, N.Y.,

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Shapley, A. H., Lincoln, J. V., International Geophysical calendar for 1963, URSI Info.

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Stern, J., An application of the peek-a-boo principle to information retrieval, Proc. Symp.

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Chem. 67, No. 4, 893-895 (Apr. 1963)

Stern, K. H., Oxidation of metals in salts. Silver in sodium chloride, J. Phys. Chem. 66,

No. 7, 1311-1317 (July 1962).

Stevens, M. E., Mechanical reading of characters and recognition (Proc. Intern. Patent

Office Workshop on Information Retrieval) , 125th Anniversary of the U.S. Patent Act of 1836, Pt. II, p. 205 ( 1962)

Stewart, R. B., Smith, R. V., Strobridge, T. R., Current trends and prospects in cryo- genics, a review of the 1962 Cryogenic Engineering Conference, Cryogenics 2, No. 6, 321-324 (Dec. 1962).

Stimson, H. F., The text revision of the international temperature scale of 1948, Book,

Temperature, Its Measurement and Control in Science and Industry 3, Pt. I, 59-66

(Reinhold Publ. Corp., New York, N.Y., 1962)

Stimson, H. F., Swindells, J. F., Wilson, R. E., Temperature scales, thermocouples, and

resistance thermometers, American Institute of Physics Handb. 2d edition, Sec. 4a, pp. 4-2-4-21 (1963).

Streever, R. L., Nuclear moment of Niel from nuclear resonance studies in steady external magnetic fields, Phys. Rev. Letters 10, No. 6, 232-234 (Mar. 1963)

Streever, R. L., Bennett, L. H., LaForce, R. C, Day, G. F., Nuclear Magnetic resonance

of Ni61 in dilute alloys of nickel in cobalt, Phys. Rev. 128, No. 4, 1632-1633 (Nov. 15, 1962).

Streever, R. L., Bennett, L. H., LaForce, R. C, Day, G. F., Nuclear resonance and the hyperfine field in dilute alloys of nickel in iron, J. Appl. Phys. Suppl. Magnetism 34,

No. 4, Pt. 2, 1050-1051 (Apr. 1963)

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Book, Solid State Electronics 6, 59-61 (Pergamon Press Inc., New York, N.Y., 1963).

241
Tao, K., A theoretical study of sporadic-^ structure in the light of radio measurements,

Book, Ionospheric Sporadic E, cd. E. K. Smith and S. Matsushita, pp. 235-257 (Perga- mon Press Inc., New York, N.Y., 1962)

Tao, K., On the theoretical study of F scatter. J. Geomagnetism and Geolectricity 14,

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Tao, K., Wait, J. R., Reflection mechanisms for sporadic E, Book, Ionospheric Sporadic

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Tryon, M., Wall, L. A., Oxidation of high polymers, Book, Autoxidation and Antioxidents,

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242
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Wait, J. R., Effective impedance of a wire grid parallel to the earth's surface, IRE Trans. Ant. Prop. AP-10, No. 5, 538-542 (Sept. 1962).

Wait, J. R., Electromagnetic waves in stratified media, Pergamon Press Inc., New York.

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Research and Geophysical Applications, ed. J. R. Wait, Ch. 6a, p. 71 (Pergamon

Press Inc., New York, N.Y., 1959)

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sea paths, IEEE Trans Ant. Prop. AP-11, No. 1, 38-^15 (Jan. 1963).

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Warwick, C. S., Delay time of polar-cap blackout and its relation to delay of geomagnetic

disturbance, J. Geophys. Res. 68, No. 5, 1561-1562 (Mar. 1963).

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Suppl. A, Pt. I, 571-572 ( 1962)

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Res. 68, No. 10, 3303-3304 (May 1963)

Warwick, C. S., The sudden ionospheric disturbance (Proc. Corfu Summer School, June

1962), Book, Radio Astronomical Studies of the Atmosphere, pp. 457-475 (NorthHolland Publ. Co., Amsterdam, The Netherlands, 1963).

Washer, F. E., Calibration of photogrammetric lenses and cameras at the National Bu- reau of Standards, Photogrammetric Eng. XXIX, No. 1, 113-119 (Jan. 1963).

243
Washer, F. E., The precise evaluation of lens distortion, Photogrammetric Eng. XXXI,

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Webster, D. 0., The Hall efTect, Student Quart, and EE Digest 1, No. 1, 82-86 (Joint

Publ. Am. Tnst. Elec. Engr. and IRE, Sept. 1962)

Weinstock, J., On the three-particle scattering operator in classical gases, Physical Letters 3. No. 6, 260-262 (Amsterdam, The Netherlands, Feb. 1963).

Weiss, G., A survey of some mathematical models in the theory of reliability, Rook,

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Weiss, G., On the pedestrian queueing problem. Bull. ISI XXXIX, Pt. 4, 163-168 (1962).

Wells, J. S., Daywitt, W. C., Miller, C. K. S., Measurement of effective temperatures of microwave noise sources, IRE Intern. Conv. Record Pt. Ill, pp. 220-238 (1962).

Weygand, F., Simon, H., Kell, K. D., Isbell, H. S., Sniegoski, L. T., Tsotope effect in the

recrystallization of D-mannose-l-f phenylhydrazone, Anal. Chem. 34, 1753-1755 (Dec.

1962)

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Wiese, W. L., Present status of our knowledge of atomic transition probabilities, Book,

Proc. Xth Colloquium Spectroscopicum Internationale, ed. E. R. Lippincott and M.

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Wiese, W. L., Paquette, D., Solarski, J., Profiles of Stark broadened Balmer lines in a hvdrogen, Phys. Rev. 129, No. 3, 1225-1232 (Feb. 1963).

Wildhack, W. A., Standards for the 70s, Ind. Res. 5, No. 3, 15-20 (Mar. 1963)

Wilson, B. L., Research in ASTM. Mater. Res. Std. 2, No. 8, 694-695 (Aug. 1962).

Woelfel, J. B., Paffenbarger, G. C, Changes in occlusion of complete dentures caused

by a pipe habit: a case report, J. Am. Dental Assoc. 66, No. 4, 478-455 (Apr. 1963).

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Chem. 34, No. 10, 1328-1330 (Sept. 1962).

Wolford, R. K., Kinetics of the acid-catalvzed reaction of acetal in water-acetone solvents

at 15, 25, and 35°, J. Phys. Chem. 67, No. 3. 632-636 (Mar. 1963).

Wolford, R. K., Bates, R. G., Kinetics of the hydrolysis of acetal in A^-methylpropionamide- water and Af-W-dimethylformamide-water solvents at 20, 25, 30, and 40°, J. Phys.

Chem. 66, No. 8, 1496-1500 (Aug. 1962).

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Wyckoff, H. O., Allisy, A., Aston, G. H., Barnerd, G. P., Hubner, W., Loftus, T. and

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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:

Ayre, Vivian E., No. 3,041,465, June 26, 1962. Auxiliary power supply. (Navy.)

Bowen, Rafael L., No. 3,066,112, November 27, 1962. Dental filling material comprising

vinyl silane treated fused silica and a binder consisting of the reaction product of bis phenol and glycidyl acrylate.

Bowman, Horace A., and Macurdy, Lloyd B., No. 3,074,498, Jan. 22, 1963. Device for minimizing the effects of mal-centered balance pan loading.

Bowman, Horace A., No. 3,092,193, June 4, 1963. Substitution balance. Brenner, Abner, and Reid, Walter E., No. 3,072,983, Jan. 15, 1963. Vapor deposition of tungsten. (Navy)

Cordero, Fidel, and Armstrong, Richard W., No. 3, 078,719, Feb. 26, 1963. Airplane

cabin pressure error or deviation indicator. (Navy.)

Cordero, Fidel, and Armstrong, Richard W., No. 3,084,549, April 9, 1963. Aircraft cabin

pressure error indicator. ( Navy.

Couch, Dwight E., Shapiro, Harold, Brenner, Abner, and Connor, Jean H., No. 3,046,205,

July 24, 1962. Nickel-aluminum alloy coatings. (Navy.)

245
Hardy, Richard J., Martin, Kenneth B., and Jacobs, Robert B., No. 3,054,289, Sept. 18, 1962. System for measuring net positive suction head of pumps.

Huntoon, Robert D., No. 3,069,113, Dec. 18, 1962. Antenna system for an ordnance

missile. (Navy.)

Jones, Frank E., No. 3,058,079, Oct. 9, 1962. Hygrometer elements. (Navy.)

Kaeser, Robert S., No. 3,052,064, Sept. 4, 1962. Glassblower's safety manostat and

system.

Kessler, Karl G., and Schweitzer, Walter G., Jr., No. 3,046,473, July 24, 1962. Very

narrow-pass filter using Zeeman-split absorption lines. Koidan, Walter, No. 3,054,864, Sept. 18, 1962. Instrument for reciprocity calibration

of electroacoustic transducers. (Commerce.)

Lloyd, Edward C, Hutton, Ulric O., Johnson, Daniel P., and Zoranski, Henry J., No.

3,088,168, May 7, 1963. Multiple-anvil high pressure apparatus.

Mandelkem, Leo, and Roberts, Donald E., No. 3,090,735, May 21, 1963. Method for making a fiber with reversible dimensional changes.

Marton, Ladislaus L., and Simpson, John A., No. 3,069,592, Dec. 18, 1962. Electrostatic filter lens or mirror.

Mason, Henry L., No. 3,079,080, Feb. 26, 1963. Crane warning system. (Navy.)

McClintock, Ralph M., No. 3,078,708, Feb. 26, 1963. Tensile cryostat. (Air Force.)

Nelson, Robert C., No. 3,093,820, June 11, 1963. Automatic radar monitor and alarm

device. (Licensed to the United States of America as represented by the Secretary

of Commerce.)

Orem, Theodore H., No. 3,060,065, Oct. 23, 1962. Method for the growth of preferentially

oriented single crystals of metals.

Pitts, Joseph W., No. 3,057,381, Oct. 9, 1962. Method and apparatus for stretch-forming

wire-grid strain gages. (Navy.)

Pummer, Walter J., and Wall, Leo A., No. 3,046,313, July 24, 1962. Preparation of pentafluoroiodobenzene (Navy.)

Pummer, Walter J., and Wall, Leo A., No. 3,075,018, Jan. 22, 1963. Tris-(pentafluorophenyD-phosphine and method of making the same. (Navy.)

Ruehrwein, Robert A., No. 3,062,730, Nov. 6, 1962. Method of making ozone. (Army.)

Saunders, James B., No. 3,043,182, July 10, 1962. Interferometer for testing large

surfaces. Shapiro, Gustave, No. 3,045,202, July 17, 1962. High frequency coaxial coupling.

(Navy.)

Silberstein, Richard, No. 3,095,538, June 25, 1963. Satellite relay station using an- tenna diversity selection. Weir, Charles E., Van Valkenburg, Alvin, and Lippincott, Ellis R., No. 3,079,505, Feb. 26, 1963. High-pressure optical cell. Wexler, Arnold, Krinsky, Albert, and Garfinkel, Samuel B., No. 3,022,667, Feb. 27, 1963. Adsorption electric hygrometer. (Navy.)

246

U.S. GOVERNMENT PRINTING OFFICE : 1964 O 714-6911