Annual Report 1956

National Bureau

of Standards

U. S. Department of Commerce

UNITED STATES DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

Annual Report 1956

National Bureau

of Standards

Miscellaneous Publication 220

For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price 60 cents
ii
Contents

Page General Review 1

1.1. Introduction 1

1.2. Technical Activities 2

1.3. Administrative Activities 10

1.4. Publications 12 Research and Development Program 12

2.1. Electricity and Electronics 13 Fundamental electrical units 13, Electrochemistry 14, Electromotive

-

force series for solid and molten chlorides 15, EMF-temperature

hysteresis studies 15, Gassing of dry cells 15, Improvements in measuring techniques 16, Automatic microimage file 16, Microfilm - to-punched-card conveter 16, Magnetic-core transducer 16, Mechanized production of electronics 16, Electronic miniaturization techniques 17, Miniaturized receiver 17, Preferred circuits 17, Research on electric spark discharge 17.

2.2. Optics and Metrology 18 Intercomparison of length standards 18, New standards 19, Precision

liquid light niters for photographic sensitometry 19, Size of color

differences 19, Dictionary of color names 20, Interlaboratory photometric intercomparisons 20, Refractometry 20, Photogrammetry

20, Image evaluation 21, Waviness of mica 21, Aerial reconnais- sance photography 21, Aviation lighting 21.

2.3. Heat and Power 22 Temperature standards 22, Low-temperature research 24, Thermodynamics 25, Lubrication 27, Engine fuels 28, Pneumatic systems

29.

2.4. Atomic and Radiation Physics 30

Spectroscopic research 30, Standards of isotopic abundance 30, Semiconducting materials 31, Field-emission X-ray microscope 32, Electron-optical studies of low-pressure gases 32, Microwave ab- sorption 32, Radioactivity 33, X-ray standards 33, High-energy

accelerator research 34, Reciprocity laws for X-rays 35, Medical

X-ray rooms 35, National photoneutrons standard 36, Low-energy

electron scatter 36.

2.5. Chemistry 37

Rare-earth elements 37, Dielectric constant of water 38, Acids and

bases in nonaqueous solvents 38, Thermochemistry 38, Analytical

and physical chemistry 39, Special investigations and developments

40.

2.6. Mechanics 40

Vibration pickups 41, Pressure measurement 42, Forces produced by

waves 43, Origin of turbulence 43, Culvert hydraulics 43, Creep of

aircraft structural joints 44, Vibration of telephone wires 44, Hightemperature strain gages 45, Milk meters for trucks 46, Jet-engine

controls 46, Jet -engine combustors 47.

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Page

2.7. Organic and Fibrous Materials 48 Dynamic bulk modulus of polymers 48, Heat of vulcanization of rubber 49, Analysis of rubber mixtures 49, Temperature control for mixing rubber compounds 49, Static charge generation in military

clothing 50, Shock loading of fibrous materials 51, Properties of

glass fibers 51, Mildew on leather 52, Determination of lignosul- fonates in tannin compounds 52, Sounding balloons 52, Statistical treatment of test results 53, Thermal decomposition of cellulose 54, Radiation chemistry of high polymers 54, Plastic packaging materials 55, Plastic eyeshields 55, Plastic springs 56, Electronic meas- urement of adhesion 56, Crazing of plastics 56, Dental resins 57, Dimensional accuracy of dentures 57, Crystallography of tooth enamel and dentin 57.

2.8. Metallurgy 58

Constitution diagrams 59, High-strength steels 59, Slack-quenched

steels 60, Temper embrittlement 60, Titanium 60, Mechanism of deformation 60, X-ray studies of stresses 61, Fatigue 62, Corrosion

62.

2.9. Mineral Products 64 High-temperature X-ray diffraction 64, Engineering properties of ceramic materials 65, Phase-equilibria investigations 65, Immiscibility of liquids in glass-forming systems 66, Bonding mechanism of ceramic coatings to stainless steel 66, Mechanism of plasticity in clays 67, Physical properties of glass at elevated temperatures 67, Standard X-ray diffraction patterns 67, Experimental methods for melting special optical glasses 68, Crystal structure of inorganic materials 68, Relation between structure and ferroelectricity 68, Chemical and physical properties of cementing materials 69, Laboratory tests versus performance of porcelain enamels 70, Compressibilities of alkaline earth oxides 70. 2.10. Building Technology 71 Shrinking stresses in masonry 72, Masonary calking materials 72, Evaluation of hand-portable fire extinguishers 72, Mechansim of

fire extinguishment 73, Thermal insulating values of reflective surfaces 73, Heating and air conditioning of underground struc- tures 73, Insulated refrigerated structures 73, Asphalt roofing 74. 2.11. Applied Mathematics 74 Numerical analysis 75, Digital computation 76, Statistical engineering 77, Mathematical physics 78. 2.12. Data Processing Systems 79 SEAC 80, Analog computers 81, Development of new computers 81, Semiconductor devices 81, Transistor switching circuits 82, Magnetic shift register 82, Gas diode work 83, Computer circuitry

packaging 83, Communication link 83, Data processing applications analysis 83, Patent search studies 84, Training program 84.

2.13. Cryogenic Engineering 84 Pumps for liquefied gases 86, Liquid-oxygen transfer systems 86, Flow of liquefied gases 87, Liquid-hydrogen bubble chamber 87, Cryogenic processes 87, Low-temperature properties of materials 88, Liquefaction of gases 89.

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2.14. Radio Propagation

Radio Propagation Physics

Upper atmosphere physics 90, Radio noise from the planet

Jupiter 91, Airglow 91, A new type of ionospheric storm 92, Trans -Atlantic communication system using VHF ionospheric

scattering 93, The extreme range of ionospheric scatter communication 94, Sporadic E 94, Automatic data processing 95, International Geophysical Year 95. Radio Propagation Engineering

Radio studies of atmospheric turbulence 96, Extending the scope

of the atmospheric radio -noise program 96, Propagation from

a transient dipole source 97, TACAN investigation 97, Airborne

refractometer 97, Propagation measurements in the Pacific Coast region 98.

2.15. Radio Standards

Attenuation measurements 99, Dielectric and magnetic materials 99, Frequency and power stabilizers for precision measurements 100, Frequency standards and radio broadcast services 101, Impedance

standards 102, Microwave spectroscopy of gases 102, Power

measurements and standards 103, Voltage standards 103.

2.16. Basic Instrumentation 104 New instruments 105, Instrument reference service 106, Indexing

system 106, Surveys 107.

3. Calibration, Testing, and Standard Samples 107

3.1. Retention of Service Fees 108

3.2. New Calibration Facilities and Equipment 108

Electronic calibration center 108, Anechoic chamber 109, Large

capacity balances 109, Improvement in gage-block measurement

109.

3.3. Calibration Services 110

3.4. New Standard Samples 112

3.5. Testing for Government Purchase ^ 113 Cement 113, Lamps 114, Mapping cameras 114, Organic and fibrous materials 114, Building materials 114.

3.6. Assistance to Other Laboratories 114 Cement reference laboratory 115.

3.7. Special Tests 116

4. Cooperative Activities 116

4.1. Federal Specifications 117

4.2. Methods of Test 118

4.3. Industry Specifications 118

4.4. Cooperative Research With Industry 120

4.5. Weights and Measures 122

4.6. Radiation Protection and Measurements 124

4.7. Educational Program 125

4.8. International Cooperation 126

4.9. Other Cooperative Activities 128

Safety codes and building research 128, Heat and temperature measurements 130, Standards for fuel gas 130, Dental materials

131, Applied mathematics 131, Engine laboratory discontinued

132, Radio propagation services 133.

Page8990

96

98

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Page

5. Appendixes 134

5.1. Organization 134

5.2. Fiscal Data on NBS Program 137

5.3. Advisory Committees 137

5.4. Awards and Honors 139

5.5. Public Law 940 Authorizing Retention of Fees 140

5.6. List of Publications 141

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1. General Review

1.1. Introduction

During the past year, the National Bureau of Standards has continued

its concerted effort to strengthen its programs by increasing the basic

research undertaken, and by developing proper technical balance in all Bureau activities. With the help of Bureau technical advisory committees, the scientific programs of the Bureau have been carefully reviewed

and steps have been taken to follow recommendations to meet the growing

critical needs in various fields of science and industrial technology.

The Bureau recognizes as its principal mission the conduct of research

related to the development of standards of physical measurement, to the

development and improvement of methods of measurement, to studies

of the basic properties of materials, and to investigations leading to a more accurate determination of basic physical constants. By undertaking

work related to this mission, the Bureau can best serve the scientific and

technological advancement of the Nation. The Bureau recognizes that

its work can be of great benefit to the national economy by providing

technical organizations and laboratories with basic data related to standards and measurement. These data can then be applied to the

development of new or improved products, new and better devices, and

improved production and technological service to the public.

The role of standards research and development in this context can

then be more adequately understood. Its importance and influence can

thus be made more widely effective. Standards and effective measure- ment techniques provide a basis for confidence in production and commerce. But even more they provide the basis of continuous technical

and industrial achievement. Standards underlie the Nation's modern

technological and industrial health; they are the basis for mass-production

methods that give a high standard of living. In this introduction it seems appropriate to summarize the nature of

the Bureau's work. By virtue of its responsibility for the custody, maintenance, and establishment of the Nation's primary standards of physical

measurement, the National Bureau of Standards serves Government,

science, and industry. The Bureau is the source for physical standards

used in our modern economy. For industry and science, the Bureau

performs critical calibrations of working standards and distrib- utes standard samples for use in production and research. For

Government, the Bureau develops methods for acceptance testing of materials in procurement and helps devise codes and specifications. In

addition, the scientific staff of the Bureau provides technical advice to various scientific and Government groups and undertakes a large variety

of studies to meet the special needs of other Government agencies. To

perform all the above services effectively, the Bureau must retain a highly competent staff and must conduct active and imaginative basic

research in all of the fields of the physical sciences, especially as such

research relates to the Bureau's basic mission.

1
1.2. Technical Activities

Standards and Measurements. To meet the requirements of science

and industry for standards and methods of physical measurement, the

Bureau carried on research and development in widely diverse fields of the physical sciences. Thus, to improve the accuracy of standard re- sistance thermometer calibrations, new apparatus was developed for obtaining the boiling point of oxygen. In this apparatus temperature

is automatically controlled to within a 10-thousandth of a degree and

pressure measurement errors are reduced to a negligible level. To meet

the needs of nuclear research, the Bureau redetermined the emission rate of the Nation's primary standard photoneutron source. For this purpose, an absolute calibration method was developed that is more precise and more easily performed than most existing techniques. Under the sponsorship of the Air Force, a new pressure standard covering the range below

two inches of mercury was completed in preliminary form. Improved

measurements of low pressures in this range (corresponding to altitudes

above 80,000 feet) are needed for instrumentation of high-performance

military aircraft. New polonium-210 alpha -particle standards having

great mechanical durability were developed, and beta- and gamma-ray solution standards of hydrogen-3, potassium-42, zinc-65, and tantalum-182 were made available for distribution. At the request of the United States Geological Survey and under the sponsorship of the Atomic Energy Commission, the Bureau undertook a program of preparing and distributing

standards of isotopic abundance. These standards are for use by laboratories throughout the world in determining the age of minerals and in deducing the temperature and other physical conditions of the earth in various geological periods. A set of approximately 60 impedance standards was completed to facilitate calibration of high-frequency impedance

measuring instruments. Also, a new technique for making precision

measurements of impedance at microwave frequencies was developed.

During the year standard resistors and standard cells used to maintain

the ohm and the volt were submitted to the International Bureau of

Weights and Measures at Sevres, France, for comparison with the inter- national standards. The United States standards were found to differ from the international standards by less than one part per million. Properties of Matter and Materials. Studies of matter and materials

ranged from basic research on frozen molecular fragments to development

of high-temperature coatings for jet turbine blades. In the low-temperature studies a technique was developed for capturing and storing large

numbers of highly reactive molecular fragments at temperatures near

absolute zero. By this method unstable atoms and free radicals, known

to exist but momentarily in flames and hot gases, are produced in an

electric discharge, frozen into immobility, and trapped into solid form.

Because these atoms are frozen in the excited state, they can be conveniently studied by optical spectroscopy. In the Bureau's experiments

2
solids were produced containing atomic nitrogen and oxygen, and possibly

atomic hydrogen and an unstable hydroxy molecule. These solids have

very unusual properties and when warmed they combine very actively,

releasing large quantities of heat energy. This method of storing free radicals appears to have broad possibilities for fundamental research. In such fields as solid state physics and basic

chemistry, the trapped atoms could be used as powerful probes into the

solids containing them. From a study of their properties, information

could be obtained about the arrangement of the atoms and molecules

in the solid and about the forces acting on them. Similarly the mechanism of diffusion of atoms and of reactions between atoms and molecules

could be studied.

Other low-temperature research showed the feasibility of a potentially

low-cost method for obtaining deuterium (heavy hydrogen) by low-temperature distillalion of liquid hydrogen. With the advent of electrical energy from nuclear power, a considerably increased demand for heavy

water can be expected, and its cost will be a significant factor. The heavy

hydrogen obtained by the distillation process might then be used in making heavy water. Plans are now being made for construction of a pilot

plant to evaluate the process on a larger scale. In research on semiconducting intermetallic compounds, information was obtained having an important bearing on the further improvement

of electronic devices such as transistors and photodetectors. The binary

compounds of indium and antimony and of magnesium and tin were

synthesized in the form of extremely pure single crystals and their electrical, optical, mechanical, and thermal properties were measured. In

this way increased knowledge was obtained of the behavior of semiconducting materials.

Because of its structural strength at high temperatures, molybdenum

would be useful for the turbine blades of jet engines were it not for its ease of oxidation, which becomes serious above 800° C. In work per- formed for the Navy Bureau of Aeronautics, a process was developed

for electrodepositing nickel-chrome protective coatings on molybdenum.

These coatings have afforded molybdenum protection in excess of 1,000

hours at 1,000° C. Basic knowledge of the reac tions involved in the thermal decomposition

of cellulose is needed to develop new nonflammable textile materials and

methods of treating present textiles to render them more flame -resistant. In an investigation sponsored by the Army Quartermaster Corps, it was

found that by modifying the cellulose structure, cellulosic materials could

be made more flame-resistant. The modification of the chemical structure evidently caused the molecules to break up differently, so that their de- composition products contained more of the nonflammable materials,

such as water and carbon dioxide, and less of the highly flammable tarry

materials.

3
Another development in textile research was an instrument for measuring the stresses and strains produced in yarns, fabrics, and films when

they are subjected to transverse impact at speeds up to 150 miles per

hour. The ability of textile yarns to withstand high-speed impact

stresses, or shock loading, is becoming increasingly important to modern

industry and national defense. Extremely high rates of strain are experienced by airplane tire cords during landing, by seat belts and

safety lines when accidents occur and by the fabric, shroud lines, and

webbing during the opening of a parachute. In high-speed industrial

sewing the thread is subjected to high-frequency cyclic accelerations which

may equal several million centimeters per second per second, and similar

conditions may be attained in high-speed processing of fibers. To pro- vide design data for these various applications, the Bureau has been

making an extensive study of the behavior of textile yarns under very

high-speed impact. Supported in part by the United States Army

Quartermaster Research and Development Command, the study is providing data that are useful in establishing specification requirements

for the webbing of parachutes.

Plastics research sponsored by the Army Ordnance Corps led to a

practical procedure for mass-producing plastic springs from glass fiber- reinforced resin. Until now plastic springs have been little used because

suitable techniques for making springs of the types needed have been

lacking. However, springs formed by this process have desirable mechanical properties for a wide range of applications. They also have a number of advantages for special purposes. For example, they are non- magnetic and have low electrical and thermal conductivity. They can be

molded directly to dimensions without developing any considerable

internal stress. Their high corrosion resistance should make them of

value for applications in chemical plants and installations subject to acid

fumes or to salt air. Other applications may benefit from the strengthto-weight ratios of plastics, which are often higher than those obtained

with spring-making metals. Also, the broad range of transparent and

colored materials that can be used makes striking decorative effects possible.

Data Processing Systems. This program, embracing both digital and

analog electronic computers, includes research, development, systems

design and analysis, and technical advisory services. During the past

year an increasing number of requests were received from Government

agencies for advice on the use of high-speed digital techniques in new

areas such as massive paperwork operations, control systems, and simulation, as well as in the solution of specific technical problems.

As in previous years, the Bureau's high-speed digital computer, SEAC,

was used to solve a variety of problems in science, engineering, and

management. Work continued on the electrostatic memory for SEAC,

and additional input-output circuitry was installed for greater efficiency

and convenience of operation.

4
In computer research, emphasis was placed on the logical systems

design of high-speed digital computers. Studies in this area are directed

toward more effective means for organizing electronic components into

systems for carrying out computing and data processing operations.

Development of more advanced logical systems is expected to make

possible considerable increases in over-all speed and computing power

without imposing corresponding increases in the performance requirements of the electronic components. Thus far, improved designs have

resulted in addition and multiplication units capable of operating 150

times faster than those in SEAC constructed from essentially the same

components.

To prevent radioactive material from falling on inhabited areas after a nuclear explosion, extensive calculations must be made when tests are planned to determine the fallout pattern. With high-speed electronic

digital computers, such laborious hand computation can be eliminated

and the calculation time reduced to 15 minutes. However, the digital

computers are usually large, permanent, expensive installations. To

provide even faster predictions with portable, relatively inexpensive

equipment, the Bureau developed a special-purpose analog computer for the Weather Bureau and the Atomic Energy Commission. This computer

gives instantly, within an area of 250 miles of "ground zero," the radioactive fallout pattern resulting from a nuclear detonation. The pattern

is presented visually on the face of a cathode-ray tube, over which a map

on a transparent backing can be laid. Two models of the fallout computer were sent to Eniwetok, Marshall Islands, and were used in predicting the distribution of radioactivity following the explosion of nuclear

weapons in May 1956. In the event of nuclear attack on this country,

the computer should be very useful to civil defense. Special Electronic Devices. Two machines were developed to help

solve the information storage problems now being encountered by Government agencies. One of these is an automatic microimage file; the other

is a microfilm-to -punched-card converter. The microimage file provides rapid access to any one of 10,000 information containing frames recorded in miniature on a 10-inch-square sheet of

microfilm. It is particularly applicable where large volumes of data must

be assembled in a predetermined sequence from a master random file. The machine combines electronic circuitry with precision servomechanisms. It operates on a continuous basis, automatically searching the

microfilm and printing out one frame every 2 seconds. Information may

be in the form of pictures, drawings, fingerprints, sets of numbers, letters or other symbols, or even single stages of electronic circuit diagrams.

The microfilm-to -punched-card converter was devised to aid the

Weather Bureau in meeting the problem of storing weather records. At the present time punched cards containing weather data almost fill the space available for such records, and their volume is, of course, continually growing. The converter selectively scans microfilmed records of

5
punched cards and restores the information to the punched-card form.

Thus, the present collection of punched cards can now be destroyed and

individual cards replaced later as needed. The space required for the

microfilm records will be only about one -hundredth of that needed under

the present system.

Radio Propagation. Of broad significance to industry and the armed

services was a program of research and development on the forward

scatter of radio waves. This recently discovered mode of radio propagation promises to extend greatly the limits of long-distance communication.

Through application of scatter propagation, new frequency channels can be opened up to long-range use, new path lengths can be utilized, and

reliable service can be provided far beyond the line -of-sight limit in the

extreme high-frequency ranges. Considerable savings may be expected

through elimination of many relay stations. Radio propagation by forward scatter is believed to result from small

inhomogeneities due to turbulence in the atmosphere. These inhomogeneities scatter radio waves in all directions, but predominantly forward.

^Arth properly designed equipment, the scattered signal can be received over long distances along the earth's surface even though the direct wave

has gone off into outer space. Although this phenomenon has been known to science for several years,

its successful application to radio communication has required extensive

research by a number of cooperating laboratories. Thus, for more than

5 years, forward scatter has been the subject of experimental and theoretical investigation at the Bureau. Sponsored by the Department of

Defense, this work has not only provided insight into the nature and

causes of the scattering process but has also laid much of the groundwork

for effective application of forward scatter in practical communication

circuits. The NBS program has included both ionospheric and tropospheric

forward scatter. Ionospheric scattering takes place in the lower part of

the ionosphere—a region of electrified particles 40 to 200 miles above the

surface of the earth. Tropospheric scattering occurs in the part of the

atmosphere that lies below the ionosphere.

Recently the Air Force requested the Bureau to undertake consulting,

design, and supervisory responsibility for construction of a trans -Atlantic

communication system using ionospheric scattering in the VHF (veryhigh-frequency) region. Previous experimental circuits were extended

to provide a complete operational system from Maine to England by way

of Greenland and Iceland. The detailed engineering design of the system was worked out with the aid of Page Communications Engineers, Inc., and the installation was contracted to that firm. To provide information on the extreme range of ionospheric scatter communication, an experiment was carried out over an extended period

between Newfoundland and the Azores. This experiment demonstrated

6
Four of the Bureau's sixteen technical divisions make up the Boulder Laboratories at Boulder, Colo. Three radio divisions are housed in the radio building, top. A new wing now under construction will house the Electronic

Calibration Center. On the same site is the Cryogenics Engineering Laboratory whose main building is shown in lower picture.

7
that regular communication by ionospheric scattering is feasible at a range of 1,400 miles, provided special siting conditions exist and are properly utilized. International Geophysical Year, At the close of the year preparations were well under way for NBS participation in the International Geophysical Year (IGY) of 1957-58. During the IGY, scientists of more

than 40 nations will make simultaneous worldwide observations and

measurements of physical phenomena related to the earth, its interior,

its crust, its oceans, its atmosphere, and its immediate cosmic environment. The results of this international enterprise will provide a greater

understanding of earth physics, and will have direct application to every- day human life in such fields as navigation, communication, instrumentation, and standards of measurement.

The United States National Committee for the IGY, organized by the

National Academy of Sciences—National Research Council, is planning

and directing United States participation in the program. The National

Bureau of Standards will be principally concerned with the gathering of

data on various atmospheric phenomena affecting radio propagation.

These include sunspots, radio noise, aurora and airglow, and disturbances

in the ionosphere. On the basis of observed solar and geomagnetic activity, the Bureau will select Special World Intervals, during which most

of the observing parties throughout the world will undertake accelerated

observing schedules. The Bureau will also assist in the earth satellite program of the IGY.

Although the taking of data for the IGY does not officially begin until July 1, 1957, considerable technical activity has been required in connection with those portions of the program assigned to the Bureau. Thus,

for study of the night airglow which results from excited molecules and

atoms in the upper atmosphere, a recording telescopic photometer was

developed with greater spectral resolution and more rapid sky coverage

than previously available. Six photometers of the improved design are being constructed for IGY observing stations, two to be operated by the

Bureau and the remainder by other organizations.

The Bureau will be primarily responsible for vertical sounding of the

various layers of the ionosphere. To this end, steps were taken to supply

14 new ionospheric sounding stations with vertical-incidence ionosphere

recorders of improved design. Six of the stations will be in the Antarctic,

five of them operated by NBS, and four in South America manned by

Bureau-trained personnel. Because of the long logistic lead time re- quired, equipment has already been sent to the Antarctic for installation of ionospheric sounding stations at the South Pole and at the Marie Byrd

Land station. Siting studies were also under way for the observation of

ionospheric forward scatter in equatorial regions.

Calibration, Testing, and Standard Samples. The Bureau's calibration

activities are an outgrowth of its custody of the national standards of

physical measurement. Periodically the master standards used in in- 8
dustry or by other laboratories must be checked against these national

standards. Such calibration services are vital to industrial and scientific progress, insuring the accuracy of working standards throughout the

Nation. Testing, on the other hand, is almost entirely confined to requests from Federal agencies, usually in connection with quantity purchase of materials like cement for Government use. New calibration equipment completed during the year included an

anechoic chamber, or "dead, room," for calibration of microphones and

sound level meters, two precision balances of 1,000- and 2,500-pound

capacities for standardizing test weights, and a mechanical comparator

for gage-block calibration. At the close of the year, construction had

begun on a new Electronic Calibration Center that is being set up at the Bureau's Boulder (Colo.) Laboratories to meet the urgent needs of the

armed services for accurately calibrated electronic equipment.

Approximately 36,000 standard samples of chemicals, metals, and alloys were issued to industrial and research laboratories. Standard samples

are materials that are certified for chemical composition or for some

physical or chemical property, such as heat of combustion, melting point, or index of refraction. They provide precise bases of comparison so that,

for example, the manufacturer of a chemical can control its purity by

comparing his product with the standard sample. Standard samples

make possible uniform measurements of heat and temperature, define the

colors of paints, and calibrate the instruments that control the composition of synthetic rubbers and motor fuels. During the past year new

developments in industry brought increased activity to the standard

samples program. Twenty-seven additional standard samples were is- sued, making the total number over 575. Cooperative and Consulting Services. The various advisory and cooperative activities of the Bureau are of considerable value in science, in- dustry, and Government. Services of this kind are rendered on a variety

of topics and problems to State and local governments as well as to agencies

of the Federal Government. For example, the Bureau cooperates with

State and municipal governments in the field of weights and measures. Here the Bureau has fundamental responsibility for the standards of

weights and measures whereas State and local governments possess reg- ulatory authority for maintenance of uniform procedures. The Bureau

contributes to these local bodies the means and methods whereby meas- urements in commerce may be made in a uniform manner, consistent

with the national standards.

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

through various scientific and technical committees. An important area

of interagency cooperation is in the development and establishment of Federal Specifications. These specifications are issued by the General

Services Administration. They result in purchase economies by establishing criteria that govern quality and by providing opportunity for all9
businesses to compete for Federal trade through the bid system. The

Bureau now has responsibility for preparation and maintenance of 180

Federal Specifications covering a wide range of materials and products;

it also receives for review each year approximately 500 proposed specifications prepared for the GSA by other agencies.

Another phase of technical cooperation, somewhat broader in scope, involved the Bureau's participation in the work of national and inter- national societies, associations, and standardizing bodies. During the

past year, Bureau staff members 1 eld committee memberships in more

than 110 groups such as the American Society for Testing Materials,

American Standards Association, American Society of Mechanical Engineers, American Chemical Society, and the International Committee on Weights and Measures. By participating in these organizations, the

Bureau is able to play an active part in bringing new advances of science

into the technology of American industry, in developing test methods and

criteria, in standardizing materials and products for greater economy

and improved quality, and in establishing uniform scientific standards

throughout the world.

An example is the Bureau's work on the National Committee on Radiation Protection. Sponsored by NBS and governed by representatives of 15 participating organizations, the NCRP studies problems involved in industrial and medical use of radiations and develops appropriate safety

recommendations. Studies recently undertaken by the Committee dealt with incineration of radioactive wastes, industrial and medical uses of intense high-energy electrons, and permissible irradiation levels for emergency conditions.

1.3. Administrative Activities

The Bureau's activities are of two major budgetary classes: first, the

basic programs that are supported by direct appropriations from the

Congress; second, various projects undertaken for other Government

agencies with funds transferred from those agencies.

During 1956, the total funds obligated for both areas of activity, in- cluding construction and facilities, were $21,997,846. Of this total,

about $8,306,246 came from direct Congressional appropriation for the

basic program, and the remaining $13,691,600 represented programs con- ducted for other Government agencies.

During this past year, several events have occurred that will have an

important bearing upon the character and future of the National Bureau

of Standards. Outstanding among these are two administrative occurrences: (1) approval by the Congress of the acquisition of a new site for the Bureau; and (2) implied approval by the Congress of the Bureau's

policy to strengthen its basic programs by undertaking more of its work

under direct Congressional support.

Activities relating to the first point may be summarized as follows. Congress has appropriated $930,000 for the purchase of a new site and

10
for initial planning. A 518 -acre site in Montgomery County, Maryland,

about 20 miles from downtown Washington, D. C, was acquired in July

1956 and steps are now under way for developing plans and architectural

drawings to be completed by the end of the next fiscal year. Construction

of the new facilities is contingent upon Congressional approval of the

plans and is not expected to begin before 1959. Completion of relocation of the Bureau is not expected prior to 1961. Equally important is the second point. The Bureau has felt a strong

need to reconstitute its research and development programs so that major

support came from directly appropriated funds and so that greater

emphasis might be placed upon research related to standards of physical

measurement and to methods of measurement. Since 1949, work for other Government agencies has dominated the Bureau's programs. This

has meant that a larger portion of the Bureau's technical staff was diverted

from basic Bureau research to work more directly relating to the missions

of other agencies. It has also meant that the Bureau was dependent in

large measure upon other agency support, thus seriously hampering the Bureau's ability to create a stable research environment and to pursue

long-range research goals consistent with its assigned mission. About two

years ago, the need for technical balance in the Bureau's basic programs was enunciated, especially in these two aspects: (1) increasing the level of basic research; and (2) concentrating on the Bureau's assigned mission.

This position has been supported by the Bureau's technical advisory committees who have made recommendations to increase the level of fundamental studies at the Bureau and to strengthen basic activities in several

scientific areas. Along with this general policy for achieving technical

balance, the Bureau has been seeking to reduce the number of projects

undertaken for other agencies. It is accomplishing this by carefully

screening other agency proposals and accepting only those projects that

have a general scientific value, or are closely allied to the Bureau's basic

mission, or which the Bureau can alone undertake because of its unique

facilities or competence.

Another Congressional action during the past year has had a bearing on one of the Bureau's special activities. The Bureau has now been

authorized to retain fees for services performed for industry. This will enable the Bureau to meet the continuing demand from industry for

tests, calibration, and standard samples, and to support these activities on a direct cost basis. During the past year, 12 technical committees were serving the Bureau's

scientific program (appendix, page 137). Composed of prominent

scientists and industrial representatives, these committees, which sup- plement the Bureau's Statutory Visiting Committee (appendix, page 137), are a valuable source of consultation and stimulation and serve to bring

to the Bureau the views and needs of the Nation's scientists and technologists.

408368—57 2 11
During the past year the Bureau held its second Open House or Guest

Week. More than 1,200 scientists and officials of Government, industry,

and education attended. The Guest Week theme was devoted to the

science of measurement. Major laboratories were opened to the visitors, in addition to special exhibits and a lecture by the Director.

At the end of the reporting period, total employment at the Bureau was 3,052. Most of the staff was stationed at the Bureau's laboratories

in Washington, D. C. About 700 were located at the NBS Boulder

Laboratories and at field stations in the United States and abroad.

1.4. Publications

The results of the Bureau's technical program are in general embodied

in its reports and publications. Even when the work is developmental

in nature—for example, the development of a specific device—a report

will represent the culmination of the activity, and it is this report that will often prove of most value to Government, science, and industry. The

reports and publications of the Bureau are therefore suggestive of the scope of its activities. During the year these totaled over 1,300, exclusive

of calibration and test reports and of general administrative documents.

Some 725 classified and unclassified reports were issued to other Government agencies, particularly the Department of Defense, while 591

papers and documents were published formally. Of the formal publications, some 488 consisted of scientific and technical papers, 88 of which

were published in the Journal of Research of the National Bureau of Standards (a monthly periodical) and the remainder in the journals of

various professional, engineering, and trade organizations. In addition,

approximately 75 summary reports were published in the Bureau's monthly Technical News Bulletin. The third monthly periodical of the

Bureau, Basic Radio Propagation Predictions, presented each month, for a 1 -month period 3 months in advance, radio propagation data needed in determining the best frequencies to use in long-range radio communications. Twenty-eight papers were published in the Bureau's nonperiodical

series of publications: 2 in the Applied Mathematics Series, 3 in the Handbook series, 16 in the Circular series, 3 in the Building Materials and

Structures Report series, and 4 in the Miscellaneous Publication series. A fist of publications for the fiscal year is given in the appendix, section

5.6 (page 141).

2. Research and Development Program

The Bureau's technical program is carried out through organizational

units called Divisions. These are shown in appendix 5.1. The review of

the research and development programs is presented in this section under

headings corresponding generally to these organizational units.

12
Photographs of electrical discharge show the breakdown process in air suddenly stopped at various stages prior to complete breakdown. Such

pictures, together with oscillograph records (below) of current and voltage

taken at the same time, make it possible to study the details of breakdown

phenomena that occur in one-millionth of a second or less (p. 17).

2.1. Electricity and Electronics

The work in electricity is primarily the development, improvement, and

dissemination of the standards of measurement for electrical quantities,

and the study of the properties of materials that are important to all fields of electricity and magnetism. The object is to provide electrical standards

that are as far as possible constant over long periods of time, uniform

throughout the Nation, and consistent with the fundamental mechanical

units. The work includes the dissemination of standards of electrical resistance, inductance, capacitance, electromotive force, current, power,

energy, magnetizing force, and magnetic induction.

The electronic activities include the standardization of test methods for electronic components, the study of materials and processes for component

fabrication, and the establishment of optimum designs of electronic

equipment for maximum life and reliability. In areas in which the Bureau

is uniquely qualified, electronic development programs are undertaken to meet the special requirements of NBS and of other Governmental agencies.

Fundamental Electrical Units. The program for absolute measurements

of resistance and current is a continuing one, as it is the only means

available for checking upon the stability of the electrical units that are maintained by the standards of resistance and electromotive force. During the past year the value of the ampere as measured in terms of the

resistance and electromotive force standards was determined in terms of

the basic mechanical units by means of the Pellat current balance. This

brings to completion a project started several years ago to provide an

independent check on the determinations made in 1940 with the Rayleigh

13
current balance. The results obtained with the two current balances

differed by less than 10 parts in a million. The comparison between the results obtained with the Pellat and

Rayleigh balances necessarily involves the assumption that the units of

resistance and electromotive force, as maintained by the NBS standard

cells and resistors, have remained constant between 1940 and 1956. To

avoid this assumption it was decided to repeat the measurements with

the Rayleigh balance so that results from the two balances would be

obtaiued only a few months apart. This program has been carried almost

to completion. One of the benefits accruing from repeating the Rayleigh

balance measurements will be a check upon the stability of the unit of

electromotive force as maintained by standard cells. If this check proves

satisfactory it will be repeated at regular intervals, just as the absolute

measurement of resistance is being repeated. Then for the first time the

stability of the units will be dependent primarily upon the stability of

standards of length, mass, and time, rather than upon an assumed stability

of groups of standard resistors and standard cells. The experimental procedures used to establish the units of electromotive

force and resistance require precisely constructed inductors. The induct- ances of these coils are calculated using formulas that consider the con- ductors to be mathematical filaments having no cross -sectional area. However, the copper wires used for the actual windings have a finite area, and the nonuniformity of the current distribution over the cross section leads to uncertainties in the calculations. This current distribu- tion is influenced by several factors, one of which is the strain in the wire. Therefore, the effect of strain on the properties of copper wires has

been the subject of considerable research at NBS. The results so far have served to reduce the uncertainties in the basic absolute electrical measurements.

During the past year the Bureau has again cooperated with the Inter- national Bureau of Weights and Measures at Sevres, France, by submitting standard resistors and standard cells for measurement and comparison with similar standards from other countries. Observations were made at Sevres in August 1955, and in the United States both shortly

before and after that date. The conclusions were that the units of

resistance and electromotive force maintained at NBS and at the Inter- national Bureau differ by less than 1 part per million. This close agree- ment helps to confirm the confidence in the stability of the primary electrical standards.

Electrochemistry. Under the sponsorship of the Atomic Energy Commission and the Army Bureau of Ordnance, a punched-cell wax electrolyte

battery was developed. This battery is 0.3 inch in length, 0.25 inch in diameter, weighs 0.05 ounce, and has an emf of 37.5 volts. It has a shortcircuit current of 3X10-8 ampere and exhibits an insignificant drop in electromotive force and current capacity even after 1 year of storage.

A similar battery has also been built with the same voltage and length,

14
Using the Pellat current balance, the absolute value of the ampere has been

determined in terms of the basic mechanical units (p. 13). The equipment

is operated from another room to avoid air disturbance and dimensional

changes produced by heat from the body.

but it is 0.5 instead of 0.25 inch in diameter. This larger size, weighing

0.2 ounce, gives a short-circuit current of 3X10-7 ampere. These new

batteries are unique in that the normal electrolyte is dissolved in solid polyethylene glycol instead of water.

Electromotive-Force Series for Solid and Molten Chlorides. A new emf

series gives theoretical electromotive forces for 96 different solid and

molten chloride electrolytes used in galvanic cells. The series was

arrived at both from theoretical considerations and from many calculations performed on the Bureau's electronic computer, SEAC. The work

was carried out for the Office of Ordnance Research. When listed in order of magnitude, the computed emf's provide a relative scale of chemical activity that should prove helpful to scientists and engineers working

out new processes in high -temperature chemistry. It supplements the

usual and well-known electrochemical series in aqueous and nonaqueous

systems.

EMF-Temperature Hysteresis Studies. The studies of emf-temperature hysteresis of unsaturated standard cells were completed, except for a few check runs. Some data were also obtained on a reevaluation of the

international temperature coefficient of saturated standard cells. Gassing of Dry Cells. The work for the Navy Bureau of Ships on the

rates of gassing of commercial dry cells at temperatures from 21° to 55° C

was completed. Results show that commercial dry cells gas at a rate of

0.2 ml/day at the lower temperature and at 6 ml/day at the higher temperature. These findings are important to manufacturers who wish to

seal cells in plastic or other material.

15
Improvements in Measuring Techniques. Further improvements have

been made in the use of an a-c bridge for the measurement of core losses at high induction. Measurements of core loss can now be made as ac- curately by a bridge method as by the wattmeter method. This new

bridge method has also contributed to a better understanding of the

measurement of nonlinear impedances and the treatment of harmonic

currents that arise as a result of the nonlinearity of the circuit. Further improvement of the a-c Kelvin bridge has extended its operating range up to a frequency of 6,000 cps. Both its usefulness and its reliability have been increased, especially at lower frequencies, thus

permitting more accurate determinations of the phase-defect angle for a-c shunts used as standards in current-transformer testing.

Automatic Microimage File. Development work was successfully completed on a microimage data storage and retrieval device, which provides

rapid access to any one of 10,000 microfilmed images located on a 10-inchsquare sheet of film. The instrument operates on a continuous basis;

it automatically searches the microfilm and prints out one frame every

2 seconds. It is particularly applicable where large volumes of data

must be assembled in a predetermined sequence from a master random

file. Information may be in the form of pictures, drawings, fingerprints,

sets of numbers, letters, or other symbols. Quantity and kind of data

are limited only by the size of the individual frame (Ko-in. square) and

the photographic resolution of the film emulsion.

Microfilm-to -Punched-Card Converter. A development for the United

States Weather Bureau reaching the stage of satisfactory laboratory

operation is a microfilm-to-punched-card converter. This device selec- tively scans microfilmed records of punched cards and restores the infor- mation to punched-card form. Present files of punched cards containing

weather data, accumulated over a 20-year period, have become a storage

problem. By microfilming and then destroying the present stock of

punched cards, a saving of space of about one hundredfold can be effected. Magnetic-Core Transducer. The Atomic Energy Commission and the

Department of Defense sponsored experimental and service work with

transistor circuits. Measurement and waveform inspection in the milli- ampere and microampere range are frequently required under conditions

where it is not convenient to open the circuit and insert the measuring or viewing device. Also such insertions unavoidably affect the current

flowing in the circuit. For such measurements the Bureau developed a

special transducer consisting of a toroidal magnetic core, split into two

parts that can be clamped around a wire conducting the current to be

measured. A winding is located on one or both parts of the core, and may

be connected through a suitable amplifying and filtering circuit to a measuring instrument or oscilloscope.

Mechanized Production of Electronics. The NBS-BuAer program for automatic production of modularized electronic equipment, formerly

code-named "Project Tinkertoy," was brought to a prescheduled conclu16
sion in July 1956. Sponsored by the Navy Bureau of Aeronautics as a mili- tary-preparedness measure, the initial phase of the program covered the

development of the modular design and mechanized production concepts

and culminated in a pilot-plant facility. Since these concepts were first announced in 1953, the art has been further developed and full technical

information has been released to private industry. A number of manufacturers of electronic components and equipment have shown extensive

interest and have undertaken developments similar to the Bureau's. This broadened industrial activity and the further improvements now

under way in industry make it appropriate for the Bureau to end its pilot -plant activities. Electronic Miniaturization Techniques. As one phase of a continuing

program on electronic miniaturization for the Navy Bureau of Aeronautics, a very compact, easily repaired, and highly reliable oscilloscope was

developed. This 32 -tube instrument can be maintained by subassembly

replacement. With this design, portions of the circuit can be replaced

by transistorized assemblies, thereby permitting a sound engineering

comparison between vacuum-tube circuits and their transistorized

counterparts.

Miniaturized Receiver. In another miniaturization-techniques pro- gram, sponsored by the Rome Air Development Center, the Bureau de- signed a receiver containing approximately 150 microwave components

and 1,600 vacuum tubes. In spite of the complexity of the equipment,

its plug-in assembly structure provides for rapid location and easy re- placement of faulty assemblies.

Preferred Circuits. The manual of preferred electronic circuits has

been formally published for wide distribution to promote the standardization of electronic circuits. It is the result of a program undertaken for the Navy Bureau of Aeronautics. Its main purpose is to encourage vol- untary reduction of unnecessary circuit variations in military equipment.

If standardization of electronic circuits is achieved, even in part, substantial economies will be realized. For the manufacturer, standardization will result in lower production costs, quicker shifting from development to production, lower parts inventories, simplification of mechanized

production, and conservation of engineering manpower. For the mili- tary services, standardization will result in lower procurement costs, simpler maintenance training, shorter lead time on delivery of equipment,

fewer spare parts at field installations, and greater operational reliability.

Research on Electric Spark Discharge. As part of a study of surge volt- ages, the recording speed of an unmodified cold -cathode cathode-ray oscil- loscope was compared with one provided with traveling-wave deflecting

plates. For this evaluation, a pulser was devised to give extremely fast and steeply rising or steeply falling surges. Negligible distortion was

found with the cathode -ray oscilloscope equipped with the traveling-wave

deflector when suitably terminated. This cathode-ray oscilloscope

17
Front and rear views of microimage data storage and retrieval deviee that

provides rapid access to any one of 10,000 information-containing frames

recorded in miniature on a 10-inch square sheet of microfilm (p. 16).

equipment of reliable high-speed recording performance was used to study steep-front surge breakdown when photographing sphere -plane

breakdowns for chopped surges.

2.2. Optics and Metrology

The Bureau's work in optics and metrology is principally concerned

with problems of measurement, instrumentation, and standardization.

Fields of activity include photometry, colorimetry, interferometry, optical

instruments, refractometry, photographic technology, thermal expansion,

and the calibration and maintenance of length standards. Work in progress includes improvement of the fundamental standard of luminance

(a total radiator at the temperature of freezing platinum), development

of a satisfactory procedure for defining the meter in terms of the wavelength of the radiation of a selected spectral line, and redetermination of color-mixture functions for calibrating the color standards used in industry.

Intercomparison of Length Standards. The yard, foot, and inch used

in this country by industry, as well as the meter used in much scientific work, are derived directly from the International Prototype Meter through

the United States national prototype meter, which is in the custody of

the Bureau. To insure the accuracy of the length calibrations that the

Bureau performs for Government and industry, the national prototype

meter and the various working standards of length must be rechecked

periodically because most scales ruled on metal gradually change their length. Thus, the national prototype meter is scheduled to go to the

18
International Bureau of Weights and Measures at Sevres, France, in the

coming year, to be checked against the international prototype. In preparation for this intercomparison, United States Meter bar prototypes No. 27

(the national standard), No. 21, No. 12, and No. 4 were intercompared.

These four bars are all of platinum-iridium alloy. The working standards,

used for routine calibrations, are made of alloys of baser metals and in general show a greater change with time than do the platinum -iridium

bars. During the past year, 13 of the Bureau's decimeter working standards were recalibrated. These decimeter standards were originally ruled on stainless steel by the use of light waves 25 years ago. The steels used

differ somewhat in composition and in heat treatment. Recalibration

thus not only provides current corrections to the scales, but also shows

the stability of different alloys and different heat treatments. New Standards. Standards of haze were issued for use in checking

hazemeters. The standards consist of titanium dioxide particles dis- persed in cellulose acetate laminated between glass sheets. Chromatic reflectance standards were issued for seven colors of commercial importance: safety red, international orange, safety orange,

school-bus chrome, safety yellow, safety green, and safety blue. These

standards are used to calibrate tristimulus colorimeters and also serve as physical representations of the color designations. They are made of

porcelain enamel on steel and are 4% inches square with a %-inch fold at each edge.

Precision Liquid Light Filters for Photographic Sensitometry. The

Bureau has developed five additional color filters which are used to simulate common sources of light when determining film speeds in the

laboratory. Of the liquid type, the filters have been designed for use with a tungsten incandescent lamp operated at a color temperature of

2,850° K. These filters supplement the three liquid filters for testing

black and white film which were designed by the Bureau many years ago and which have been adopted by the International Congress of Photography.

Size of Color Differences. In setting color tolerances of manufactured

articles it is important to know not only the size, or perceptibility, of color

differences but also how this perceptibility is affected by viewing conditions, such as angular size of the colors, angular separation between them,

and amount and kind of illumination used to inspect them. The Bureau

has cooperated since 1948 with the Committee on Uniform Color Scales

of the Optical Society of America in the collection of about 1,000 color standards, sampling all of the roughly 10 million colors detectably differ- ent. The sampling is intended to be uniform in the sense that each

color will be equally different from each of its 12 nearest neighbors when

judged under the conditions of commercial inspection. This collection of color standards is expected to serve as a reliable and convergent guide

in setting color tolerances of all sorts.

19
Dictionary of Color Names. The Bureau completed a comprehensive

dictionary of color names with the cooperation of the Inter-Society Color

Council (The ISCC-NBS Method of Designating Colors and a Dictionary

of Color Names, price $2.00). The end result of 4 years of research and

study, the ISCC-NBS dictionary not only includes color names from the

various fields of application but also relates all the names listed to a common, fundamental system of designation. It lists 7,500 individual

color names and defines them in simple, accurate terms that can be easily

understood by persons working in different fields. The wide interest and

demand for this type of information is illustrated by the fact that in 4 months the sales stock (3,000) has been nearly exhausted. A second

printing is in preparation.

Inter!laboratory Photometric Intercomparisons. To promote the uniformity of light measurements throughout the United States, interlaboratory intercomparisons on six different sizes or types of lamps were

inaugurated. The Bureau, one commercial laboratory, and six industrial

laboratories participated. A smaller group of laboratories is cooperating

in colorimetric intercomparisons of fluorescent lamps.

Refractometry. Large transparent synthetic crystals, suitable for lens construction, have been increasingly used for studies in the spectral

regions of the ultraviolet (rocket spectroscopy) and infrared (molecular

spectroscopy). However, before such crystals can be generally useful in lens systems, their indices of refraction and dispersion as well as the ther- mal coefficients of the indices must be determined. Measurements of

this type were carried out for several materials during the last year. The indices of cesium iodide for ultraviolet, visible, and infrared wavelengths were determined along with the dispersion and thermal coefficients. Data were also taken, out to 39 microns in the infrared, on an improved

type of mixed crystal of thallium bromide and thallium iodide. The change in refractive index was used as an indicating property to determine the time rate of recovery of a glass after subjection to hydrostatic pressure (of the order of 104 atmospheres). Data of this sort, used

to study relaxation phenomena that are basic in studies of the fundamental nature of solids, may also be correlated with studies of rate processes in chemical reactions. Photogrammetry. Photogrammetry, the science of making maps from

airplane photographs, is important to both industry and the armed

services. Its applications include small-scale mapping of continental

areas, large-scale mapping of small sites to aid in the placing of factories,

highway mapping to determine routes of minimum cost, mapping for tax purposes, and many other uses. To insure accuracy in the finished maps, camera-lens errors must be precisely determined and compensated

for. During the past year, two studies were completed dealing with cal- ibration errors and errors arising from incorrect alinement of the camera, which was found to produce asymmetric distortion and errors in the loca- tion of the principal point.

20
Instrumental measurement of color difference in the NBS colorimetry

laboratory (p. 19). A current study indicates that col or-difference meters

are likely to be more reliable in determining color differences than are human

observers. Accurate matching of colors is becoming increasingly important

to modern industry.

Image Evaluation. Photographers often have difficulty in determining

the suitability of a given lens for making photographs of a certain quality.

The Bureau has published a circular and a set of test charts which permit

measurement of the limit of resolution by the average amateur photographer. These charts have also been found useful by many professional

photographers. Now in its third printing, 9,400 copies of the circular and 5,000 copies of the set of charts alone have been sold since 1953. Waviness of Mica. Determination of the waviness of mica purchased

by the Government has been done visually. In order to speed such

determinations, the Bureau developed an objective method for evaluating

the waviness of mica for the Emergency Procurement Service.

Aerial Reconnaissance Photography. Aerial black-and-white photographs have been widely successful in military applications such as locating

enemy installations and assessing bomb damage. Special photographic

materials for each type of target to be detected were developed as part of

a project sponsored by Wright Air Development Center to sharpen aerial reconnaissance. A method was developed for detecting the amount of

rust-damage to fields of wheat and rye. This method is based on reflect- ance differences between diseased and healthy plants measured by spec- trophotometry. The technique shows clearly areas of wheat fields in- fected with rust, although ordinary photographs show nothing.

Aviation Lighting. To obtain a better measure of the distance from

which a pilot can see the runway, an experimental slant-visibility meter was constructed and installed at the Areata (California) Landing Aids

Field Laboratory. The design of this instrument is based upon the

present Weather Bureau ceilometer, originally developed at NBS. The

21
detecting unit is installed in the approach zone of the instrument runway,

and the remote indicating and recording instruments are installed in the

weather office. 2.3. Heat and Power

To provide a fundamental basis for precise measurements of heat and

power, the Bureau maintains temperature scales covering most of the

range from the lowest obtainable temperature to the highest temperature

of incandescent bodies and flames. The Bureau is also responsible for determining and maintaining standards of viscosity, heat capacity, and

heat of combustion; and it maintains the primary standards for determination of the octane number of automotive and aviation fuels. Research

is conducted to increase the accuracy of these standards and to develop

improved measuring instruments and apparatus.

From the standards of temperature, the work in heat and power broadens to include the determination of quantities of heat by calorimetry at temperatures extending over a large part of the scale. Concurrent

theoretical programs relate thermal properties to molecular structure and permit the calculation and compilation of tables of thermal properties over an even wider temperature range. Particular emphasis is placed on

investigations of electrical, magnetic, and thermal properties of matter

at extremely low temperatures. Other phases of the work are concerned

with the flow characteristics of lubricants and other fluids; high -temperature lubrication; diesel oils, aircraft fuels, and motor gasolines; and

combustion mechanisms in engines.

Temperature Standards. Temperatures on the thermodynamic scale must be more accurately known if the accuracy of thermodynamic computations is to be improved. Temperature can be determined more

precisely, however, on the practical scale, known as the International

Temperature Scale, than on the thermodynamic scale. Values of thermodynamic temperatures can then be derived from values on the Inter- national Temperature Scale if the small differences between these two

scales are known. Engineers, for example, find these differences sig- nificant in the formulation of steam tables. To meet the needs of scientists and engineers, the Bureau is carrying out an extended program of precision gas thermometry to determine the differences between these two

scales in the range of temperature from the steam point to 800° C. From the boiling point of oxygen (—182.97° C) to the freezing point of antimony (630.5° C), the standard resistance thermometer is the instru- ment adopted for interpolation between the fixed points on the Inter- national Temperature Scale. However, at temperatures above the

antimony point, less is known about the behavior of resistance thermometers and the factors affecting good thermometer design. Thus, the

present instrument for interpolations in the range from 630.5° to 1,063° C is the standard platinum versus platinum-rhodium thermocouple with its inherent limited accuracy. Studies of resistance thermom22
Precision equipment for making exacting determinations of the optical

characteristics of aerial camera lenses (p. 20). These factors are very important in photogrammetry, the science of making maps from airplane

photographs.

©try at these higher temperatures are therefore being made in anticipation

of the eventual adoption of the resistance thermometer as the accepted

interpolation instrument up to the gold point at 1,063° C. This will permit the measurement of temperature with significantly greater accuracy

in the higher range. The normal boiling point of oxygen at — 182.97° C is one of the

primary fixed points on the International Temperature Scale. It is also one of four fixed points that are used in the calibration of standard resist- ance thermometers. Formerly, fluctuations in the cryostat temperature

and errors in the pressure measurements limited the accuracy with which

the boiling point of oxygen could be realized. During 1955 a new oyygenpoint apparatus was developed in which the temperature is automatically

controlled to within ±0.0001 degree and the errors in pressure measure- ment rendered negligible. This apparatus will enable the Bureau to improve the accuracy of its standard resistance -thermometer calibrations. Above the gold point the extrapolation of the International Temperature

Scale is effected by means of the standard optical pyrometer. Although

the optical pyrometer has been a very useful instrument through the years,

its potential accuracy is limited by several factors, one of the most serious being that observations are made with the human eye. For this reason

a new pyrometer is under development in which visual observations are replaced by photoelectric detection of brightness matches.

The possibility of establishing a thermometric standard at low temperatures through the precise determination of the velocity of sound in helium gas is being investigated. Apparatus has been designed for work

in the range from 1° to 20° K, with particular effort being devoted l<> the 23
problems of maintaiDing temperature uniformity and stability over the

acoustic chamber, and the precision measurement of standing wave

patterns for wavelengths of a few millimeters.

Low-Temperature Research. The salt, ammonium hexafluorochromite, was investigated for use in a magnetic thermometer and found to possess a

large specific-heat anomaly in the neighborhood of 0.2° K. It and others

of a fluoride series with similar structure are inherently more stable and

reproducible than the more familiar hydrated paramagnetic salts. The i Bureau plans to survey other fluorides with a view to using them both in thermometers and as heat sinks for work below 1° K. An exhaustive ! investigation into the properties of chromium methylammonium alum was

brought nearer to completion with gamma-ray -heating specific-heat

measurements from 0.01° to 1° K.

Earlier experiments on nuclear orientation had produced the accidental j discovery of enormous nonresonant heating effects in a paramagnetic salt subjected to a radiofrequency magnetic field when cooled below 1° K.

This has been confirmed to be a magnetic rather than dielectric effect, and

investigations have been made on both a "helium-range" antiferro- magnetic (manganous chloride tetrahydrate) and on chromic methylammonium alum with its Neel (or Curie) point of 0.02° K. In the region

of the Neel point the relaxation time rises rapidly, and existing theories j are completely inadequate to account for this. The low-temperature ; radiofrequency heating is of interest in providing more information on

short-range order and in pointing up the directions in which theories of

magnetic interaction and relaxation times must be developed. It is possible, also, that the phenomenon can be developed for calorimetry and

absolute temperature determination below 1° K. The intensity and

uniformity of the heating effect are excellent, but its extreme temperature I dependence is a less desirable feature. Investigations of superconductivity were continued under the sponsorship of the Air Research and Development Command. This property, ! common to many pure metals and alloys, involves the abrupt disappear- ance of electrical resistance at low temperatures. During the past year

the program was devoted to an investigation of the superconducting

behavior of microscopic tin filaments called "whiskers." These filaments, | about 40 millionths of an inch in diameter, have provided new information ! concerning magnetic-field penetration in superconductors. Plans are i under way to investigate the so-called "intermediate state" in lead. The

intermediate state consists of alternating domains of superconducting

j and normal material. By measuring the domain periodicity it is possible to obtain information concerning the surface energy at a domain wall. ! A magnetic probe and auxiliary apparatus are under construction. In work supported mainly by the Office of Naval Research and the Air I Research and Development Command, a technique was developed for capturing and storing large numbers of highly reactive molecular frag- -

j ments at temperatures near absolute zero. By this method, unstable

24
atoms and free radicals, known to exist but momentarily in flames and

hot gases, are produced in an electric discharge, frozen into immobility,

and trapped in solid form. Because these atoms are frozen in the excited

state, they can be conveniently studied by optical spectroscopy.

Within the last 5 years, several methods have been developed in other

laboratories for stabilizing free radicals at low temperatures. However,

the present technique has the advantage that the free radicals are stored

in highly excited states as a result of the electric discharge, making it possible to study and analyze them by spectroscopic techniques. Also,

because the radicals are collected at much lower temperatures than in previous methods, they can be stored longer in the uncombined form.

Thus far the method has produced solids containing atomic nitrogen

and oxygen, and possibly atomic hydrogen and an unstable hydroxy (OH)

molecule. These solids have very unusual properties, emitting bright

glows, blue "flames," and colored flashes of light. When warmed 20 or 30 degrees, they combine very actively, releasing large quantities of

stored energy, principally as heat. Possible fields of application for the technique include solid-state physics and basic chemistry. Here the trapped atoms could be used as powerful probes into the solids containing them. From a study of their properties, information could be obtained about the arrangement of the

atoms and molecules in the solid and about the forces acting on them.

Similarly, the mechanism of diffusion of atoms and of reactions between

atoms and molecules could be studied.

Thermodynamics. The thermodynamics program is concerned with

maintenance of heat standards, extension of basic thermodynamic theory,

application of theory to specific problems, and improvement of experimental methods used to determine the properties of materials.

A new heat-capacity calorimeter was designed and built to permit

accurate, detailed measurements on difficult materials that have a variety of forms or occur as glasses in the range from 25° to 500° C. Temperature control in the region surrounding the calorimeter is accomplished

automatically by electronic equipment which reads, records, and regulates

the temperature, and also computes required corrections. This calorimeter has been employed to measure the heat capacity of aluminum

oxide, a standard material selected by the Calorimetry Conference. It

is currently being used to determine the thermodynamic properties of

sulfur which are of interest in the chemical and petroleum industries. A new derivation was worked out for the Boltzmann equation, the

basic equation of the kinetic theory of gases. This equation described

the progression to equilibrium of an initial nonequilibrium state of a gas.

It is derived classically on the assumption that the mechanism involves

binary collisions between molecules. It has been found possible to express certain terms in the equation, which describe the effects of

collisions, as a series in powers of the density. The first term corresponds

to the classical Boltzmann equation, whereas the higher-order terms give

25
Electron micrograph of magnesium oxide smoke, showing particles as small j as 0.025 micron (one millionth of an inch). Precise knowledge of the purity,

size, and arrangement of these white cubic crystals is basic to their use as a reference standard in calibrating standards of color (p. 19).
the effects of triple and higher-order collisions among molecules and

additional effects due to the finite size of the molecules. Classical theory

neglected these effects. The term arising from triple collisions has been

worked out explicitly, and this may be applied to the problem of cal- culating the first pressure -dependent correction to the viscosit y and

thermal conductivity of a dilute gas. The theory applies at pressures up

to a few hundred atmospheres.

The thermodynamic properties of a gas may be calculated over a wide

range of temperatures if sufficient information is available on the structure

of the molecules that make up the gas. It is necessary to know both the

geometric structure—the distances and angles between the constituent

atoms—and the forces that hold the atoms together. The first type of

information may be obtained from the microwave spectrum of the substance, whereas the second is derived from the infrared and Raman spectra.

During the year a high-sensitivity microwave spectrograph was constructed. This apparatus covers the part of the elec tromagnetic spectrum

that is used in radar applications. In connection with a continuing research program on the properties of

fluorine compounds, the new microwave spectrograph was used to study

the structure of several molecules of current interest. An investigation

of the microwave spectrum of sulfuryl fluoride has settled a dispute over

the details of its structure. A joint microwave and infrared study was made of perchlorylfluoride, a recently discovered substance of considerable

technological interest. The structure of this molecule was established

and values of its thermodynamic properties were calculated. A study of the microwave spectrum of methylamine yielded interesting information

about certain special internal motions that occur in this molecule.

A project on the vibrational spectrum of halogenated ethylenes was

completed. This work was concerned with the modes of vibration of the

atoms within a molecule. Simple theories about the forces in a molecule were developed and applied to certain typical molecules whose vibrations

had been determined from experimental studies of their infrared and

Raman spectra. With the aid of high-speed electronic computing

machines, these theories were shown to give an accurate representation

of the observed spectra. The theories were then used to predict the

vibrations of a large number of related molecules. In this way vibrational

frequencies were calculated for about 20 molecules that have not yet been

studied experimentally. As a result, it is now possible to predict the

thermal properties of these substances without the need for time-consuming experimental measurements. This method shows great promise for extension to other classes of substances.

Lubrication. In aircraft accessory equipment, such as gyros, motors,

and inverters, it is highly desirable that the ball bearings be prelubricated

so as to require no further lubrication. At ordinary temperatures, ball bearings prepacked with suitable greases may be operated satisfactorily for several thousand hours. Equipment in modern aircraft, however, is

408368—57 3 27
subjected to temperatures ranging from —65° to +300° F, and in some

cases much higher. In many such applications greases are not satisfactory

because at low temperatures soaps or other thickeners cause high friction and at high temperatures chemical instability causes rapid deterioration. In previous work, supported in part by the Navy Bureau of Aeronautics,

it was shown that felt -like materials can be used to hold a supply of

suitable oil and to bleed it slowly to the races of the ball bearings. Wool

felt rings on each side of the ball bearings were used at first, but they

became badly charred at 325° F. More recently, synthetic felts that can

withstand much higher temperatures than wool felt have become available. In further work, polyester felt rings were incorporated in ball bearings. At 325° F ambient temperature and 10,000 rpm, endurance

tests were made with these rings saturated with di(2-ethylhexyl) sebacate

containing appropriate additives, and with five greases for comparative

purposes. Length of operation with the oil-soaked rings was far superior

to that of the greased bearings. Comparative tests of oil-soaked felt rings and greases, made at temperatures down to —75° F and at speeds

up to 10,000 rpm, showed greater ease of starting and lower friction at low temperatures with the oil-soaked felt than with the greased bearings.

The work is being continued with extension to higher temperatures and

speeds, including tests in gyros and other high-speed motors. Engine Fuels. In isolated military posts, it occasionally becomes

necessary to operate diesel engines on substitute fuels when a supply of

specification fuel is un available. To aid in the intelligent selection of

substitutes, a large number of fuels of diverse types were studied for the

Army Ordnance Corps, particularly in regard to the cetaue number and

the effectiveness of ignition-quality improvers. From this study, it was

possible to make general recommendations for selection of fuels to avoid

hard starting and formation of deposits.

In another investigation, the relationship between cetane number and

octane number was established for several fuels of various types. This

study allows estimation of the cetane number of a diesel fuel by measure- ment of the octane number of the fuel in a 50-percent-isooctane blend.

Thus, the Quartermaster Corps can now estimate the cetane number in the mobile petroleum-testing laboratories. The relation between the net heats of combustion of aviation gasolines ! and other more easily measured properties of such fuels was investigated.

Previous studies had shown that in certain cases net heat of combustion

of a well-defined class of hydrocarbon fuels can be expressed as a linear [ function of aniline point, API gravity, or their product, but that in general

a different relation must be used for each class of fuels. Measurements were made of aniline points, API gravities, hydrogen

and carbon contents, the contents of the four hydrocarbon types (paraffins,

naphthenes, olefins, and aromatics), and net heats of combustion for 33

grade 115/145 aviation gasolines and 7 grade 100/130 gasolines, selected - I from a total of over 200 samples submitted by various producers. When

28
Glow from atomic nitrogen frozen into a solid a few degrees above absolute

zero. The unusual properties of frozen free radicals—they emit bright glows,

blue "flames," and colored flashes of light—are being studied spectroscopically using the apparatus shown at right (p. 24).

the results were correlated with heat-of-combustion data, the estimated

standard deviation of a single observed value of net heat of combustion

ranged from ±23 to ±49 Btu per pound, depending on the parameter

studied. The observed results were also correlated with the measured

composition of the hydrocarbon mixture and expressed as an equation in three parameters: percentages by weight of olefins, aromatics, and naphthenes. The standard deviation of a single experimental value of net

heat of combustion from the resulting equation is ±15 Btu per pound,

which represents a considerable improvement over previously used

equations.

Pneumatic Systems. The greatly increased flight speed of aircraft has

stimulated interest in the use of pneumatic control and actuating systems

as possible substitutes for more conventional hydraulic systems. Various

difliculties are encountered with hydraulic fluids at the high temperatures

encountered in high-speed flight. To aid the use of pneumatic systems,

the NBS Pneumatics Laboratory has been engaged in standardization

and research on pneumatic components under the sponsorship of the Navy.

The standards- development work involves preparation of specifications

and of envelope drawings and evaluation tests of component prototypes.

The research program includes a variety of problems such as determination of thermodynamic properties of air, study of pressure and temperature history during transient flow in pneumatic systems, response of

pneumatic components to transient flow, and the explosion hazard as- sociated with pneumatic systems. The explosion-hazard investigation

is concerned with temperature-producing phenomena such as a single

rapid compression pulse or repeated rapid compression pulses of low

amplitude. Phenomena of this sort have been observed in pneumatic

systems even at low pressure. Apparatus has been constructed that

produces temperatures high enough to cause ignition of various organic

materials, such as hydraulic oils. 29
2.4. Atomic and Radiation Physics

The reliance of modern industrial technology and military defense upon

advances in atomic and nuclear physics is creating a constant demand for additional and improved standards, for new methods of measurement,

and for more extensive and precise data. The Bureau's program in atomic and radiation physics is designed to meet the most urgent of these

needs through basic and applied research on particles such as atoms,

nuclei, neutrons, and electrons; properties of radiation, particularly

gamma and X-rays and ultraviolet and infrared light; and the interactions

between radiation and particles. The results of such studies, both at the Bureau and elsewhere, are evaluated and compiled for publication in handbooks and circulars, which make the data readily available in the

most useful forms for engineers, scientists, the medical profession, and

others. The understanding of basic processes revealed by these studies

is essential to the Bureau in devising suitable standards of measurement

and in providing essential calibration services for new instruments and

materials.

Spectroscopic Research. In 1946, the Bureau began to compile information on atomic energy levels as derived from analyses of optical spectra

of atoms and ions. Such information includes precise energy values,

magnetic splitting factors, quantum numbers, electron configurations,

and excitation and ionization potentials. These data are basic to quantitative spectrochemical analysis in industry; astroyphysicists require

them for determining the chemical compositions, temperatures, and

gaseous pressures in stars; and the same data and methods can be applied

to the study of nuclear weapons.

This information is being published as NBS Circular 467, "Atomic

Energy Levels." Volumes I and II, containing data for 358 spectra of

elements 1 through 41, have been issued. Volume III, now nearing completion, deals with all known spectra of elements 42 through 57, and 72 through 89. It will contain a vast amount of new information about

heavy elements (molybdenum, technetium, ruthenium, iodine, hafnium,

tantalum, tungsten, rhenium, and actinium), characterized by very complex spectra that have been intensively investigated for many years. Two of these elements, technetium and actinium, are artificial and unstable; the first was obtained from uranium fission, and the second by

transmuting radium in a uranium pile. Milligram samples of these

elements sufficed for accurate and extensive descriptions of the spectra

emitted by neutral atoms or by singly or doubly ionized atoms, and analysis of the successive spectra yielded interesting information concerning

atomic energies and electronic structure of the two elements.

Standards of Isotopic Abundance. The mass-spectrometer research car- ried on in many laboratories throughout the world on the natural abundance of isotopes is invaluable for determining the age of minerals and for important clues to the temperature and other physical conditions of the

30
A microwave spectrometer is providing new information on the structure of

fluorine compounds of considerable technological interest (p. 27). earth when the various minerals were formed. Unnecessary uncertainty

exists, however, in available isotope -abundance data because of the lack

of common standards to which all measurements can be referred. For

this reason, the Bureau, at the request of the United States Geological

Survey and with the sponsorship of the Atomic Energy Commission, undertook a program of preparing and distributing reference samples for use

in such research. This will make it possible, for the first time, for all laboratories doing research on a particular element to work with the same material.

Samples are being made available on an international basis and will consist of elements and compounds in forms suitable for mass-spectrometer analysis. As a part of the program, the Bureau is determining the

suitability of new chemical compounds for isotope measurements and is developing convenient preparation technique. The Bureau also will serve as an international clearing house for data on the natural abundance

ratios for these samples. Accumulated data on each element will be

distributed with every sample sent out. Semiconducting Materials. In research on intermetallic compounds,

emphasis was placed on the binaries of indium and antimony and of magnesium and tin. Both compounds have been synthesized in the form

of extremely pure single crystals, and their electrical, optical, mechanical,

and thermal properties have been measured. The increased knowledge

thus obtained on the behavior of semiconducting surfaces is of great

importance for judging the feasibility or improving the operation of devices such as transistors and photodetectois.

Both InSb and Mg2 Sn show potential possibilities as photodetectors for the far infrared spectral region, the first as far as wavelengths of 7.5 microns, the second up to 4 microns. Measurements on InSb have

yielded the elastic constants of this material over a wide temperature

range. Important information has also been obtained concerning the

31
anelastic properties of this compound. An investigation of the electrical conductivity of Mg2 Sn at very low temperatures has shown that it is possible to completely separate surface and bulk conduction. Also, the

thermoelectric power of InSb has been investigated as a function of

temperature. This phenomenon in semiconductors has recently drawn

considerable attention, not only because of the theoretical implications,

but also for its possible use in power sources and refrigerating units. Another semiconductor of great interest is grey tin, because of its small

energy gap. An extensive study of the crystal growth and transformation

of this element was completed. Single crystals as long as 2 mm were produced and their electrical properties were investigated. This work

was supported by the Air Research and Development Command and the

Office of Naval Research.

Field-Emission X-ray Microscope. The development of an X-ray

microscope making use of field emission has been completed in a project

sponsored by the Air Research and Development Command. Having

a resolving power of a few microns, the prototype is a simplified instrument

which demonstrates the basic principles and design. The advantages of

this instrument over previous devices are greater compactness and simplicity. The resolution is capable of considerable improvement by further

engineering refinements. The X-ray microscope bridges a gap that exists between the conventional microscope and the electron microscope, having

a resolution between the two, but with the advantages of increased penetration for the determination of inner structures of biological specimens.

Electron -Optical Studies of Low-Pressure Gases. With the development

of high-altitude, high-speed missiles, a critical need has risen for knowledge

of the flow of extremely rarefied air and of the heating and cooling effects of a high-velocity gas stream striking a metal surface. Unfortunately,

conventional methods of flow visualization fail at an air density cor- responding to that of the atmosphere at a height of about 30 miles. In

work supported by the Office of Naval Research, a new electron-optical

method has been developed to photograph the flow pattern at densities corresponding to altitudes greater than 100 miles. The preliminary

experiments were done with a stream of cadmium vapor moving at approximately the speed of sound. The method, which is applicable to other gases or velocities, is being extended to permit measurement of the

temperature and velocity of the gas before and after reflection from a

surface. From such data, the aerodynamicist can predict the air resist- ance and heating of the surface at any speed or altitude. Microwave Absorption. Significant progress has been made in the

development of special techniques for measuring very small microwave

absorption coefficients, such as those of importance for microwave propagation in the atmosphere. For this purpose, a unique design and method

of excitation of very large cavity resonators has been thoroughly studied

and tested. The method consists mainly in the successful separation of a

single pure mode from an extremely densely populated cavity spectrum,

32
and thus considerably extends the practical range of cavity resonance

techniques. In the microwave circuitry of such techniques, an arrange- ment is required for measuring extremely minute wave-guide attenuations,

much smaller than those measurable by commercially available attenui ators. To surmount this difficulty, a special microwave circuit has been

devised which in effect multiplies the scale reading of an attenuator by

several orders of magnitude. The latter circuit should have wide application in measurements of very small absorptions, such as, for example, in the study of the absorption behavior of ferrites. This work is supported

by the Air Research and Development Command.

Radioactivity. The main function of the NBS radioactivity program is to produce radioactivity standards and to develop new means for calibrat- ing and maintaining such standards. In this latter field, considerable

attention has been given to the development and use of satisfactory liquid

scintillators. The effects of secondary solutes, oxygen removal, and lower

temperature have been investigated, and it is now possible, under special

conditions, to make a liquid scintillator more efficient than anthracene.

New alpha -particle standards of great mechanical durability, consisting

of polonium-2 10 deposited on palladium on silver disks, have been

developed. These have little or no alpha straggling and no beta component. Beta- and gamma-ray solution standards of hydrogen-3, potassium-42, zinc-65, and tantalum-182 were added to the list of those pro- duced or released for distribution. International comparisons have been

carried out between the Bureau's short-lived solution standards and those

of the United Kingdom and Canada. The United States primary radium

standards have also been compared with those of Canada and the Federal

Republic of Western Germany.

In the nuclear spectroscopy laboratory, the inner bremsstrahlung

spectra of vanadium-49 and cesium-131 have been satisfactorily compared with theoretical calculations. A more complete determination of

the disintegration scheme of silver-105 has been made and anomalies in the decay of scandium-43 resolved. The energy levels in the decay

schemes of nickel-57, iron-53, and yttrium-86 have also been investigated.

A determination of the decay rates of millicurie amounts of cobalt -60, submitted by Atomic Energy of Canada, Ltd., has been made.

X-ray Standards. To achieve uniformity of X-ray measurements not

only within this country but throughout the world, it is necessary to make

precise measurements of the constants involved in the conversion of

measurements to the amount of energy absorbed in the human body, and

insure that all of the laboratories in the world agree on their primary

measurements.

Toward this end the Bureau has been investigating some of the quantities involved. A measurement was made of the amount of energy

required for sulphur-35 beta rays to produce an ion pair in air. A value

of 33.71 d= 0.24 electron volts was obtained.

33
Control panel of a new heat-capacity calorimeter for making accurate measurements on materials difficult to study in the range from 25° to 500° C

(p. 25). Electronic equipment automatically measures, records, and controls the temperature of the region around the calorimeter. In addition, a Swedish free -air chamber was calibrated against the Bureau's primary standard. After all corrections were made, the

Swedish chamber was found to agree to within 0.5 percent with the NBS

chamber and to within about 0.5 percent with an earlier calibration per- formed at Frankfurt, Germany. In this calibration, as well as in earlier ones, it was found that the items most likely to be in error were the

diaphragm area and the electrical capacity used to determine the

ionization charge. To facilitate checking of these items without having

to transport the large free-air ionization chambers, the Bureau agreed,

at the suggestion of the International Commission on Radiological Units,

to construct a set of diaphragms and a set of standard capacitors. These

are to be loaned to standardizing laboratories in other countries for inter- comparison with their own similar equipments. In addition, the Bureau

agreed to construct a small secondary standard, which is to be calibrated

at NBS and then made available to the same laboratories. It is hoped

that the availability of these three items will reduce the extensive amount

of intercomparison required between the standardizing laboratories of the

world.

High-Energy Accelerator Research. High-energy X-rays are being

applied to food sterilization, industrial radiography, and medical therapy.

To further understanding of these X-rays and their interaction with matter, the Bureau has completed research on two basic problems that have

challenged experimenters since high-energy X-ray sources became available. The first is the measurement of energy and angular distributions

of the X-rays produced in very thin targets by monoenergetic electrons. In this phase of the work the results for certain conditions show large

departures from the approximate theories. The interpretation of many

precise experiments needed for practical applications of the high-energy

X-rays should be aided by these results. 34
The second investigation was carried out for the Air Research and

Development Command. In this study, gamma rays from carbon and

oxygen nuclei that had been excited by high-energy X-rays were detected

and measured. For example, carbon when irradiated by high-energy

X-rays emits monoenergetic gamma rays of 15 Mev. The number of

these gamma rays and their angular distribution have been determined

with specially developed Bureau equipment as part of a program to provide experimental data for nuclear structure theorists. Reciprocity Law for X-rays. Photographic film has been used extensively for measuring radiation in atomic weapon tests. It was thought

that at the high radiation intensities that occur, the energy loss due to luminescence within the photographic material might be large enough to cause competition between the process of luminescence and that of latent - image formation by high-energy radiation. However, the latent image

formed by the visible light stemming from such luminescence would

show reciprocity-law failure. In a project sponsored by the Army Signal Corps, the validity of the

reciprocity law for X-radiation of very high intensity (up to 66,000

roentgens per minute) was investigated both in the negative and in the

positive (reversal) branches of the characteristic curves for some of the

dosimeter film types. Conventional X-ray development, as well as sur- face and internal development, was employed, because it is known that

certain film emulsions tend to show reversal when processed in a surface developer, whereas generally no such effect is encountered in other types

of developer. Actually, reversal was found to occur only upon surface development of both of the film types studied. Within the experimental

error, no failure of the reciprocity law was found in the negative branches

of the characteristic curves of the films. The study of the positive branch

of the characteristic curve of one of the films revealed both reciprocity -law

failure and intermittency effects. These effects consisted not only in a

shift of the characteristic curves, but in a change in the maximum density

obtainable before the onset of reversal. In the dose -rate range investigated, higher dose rates produced smaller

film sensitivities and higher maximum densities. The latter effect ex- plains why some of the film of this type, exposed during the 1955 weapon

tests and developed in surface developer, had shown densities considerably

above those found on simultaneously developed laboratory calibration

films. Medical X-ray Rooms. The calculation of the barrier requirements

in X-ray rooms, as specified in protection handbooks, has been based on maximal assumptions for the various factors. This has provided adequate

protection, but the question has been raised as to whether or not this is realistic. To find an answer, measurements were carried out in 22 medical diagnostic radiographic and fluoroscopic X-ray rooms by means of

about 75 small ionization chambers distributed over the walls of the rooms. These chambers were read daily for several weeks in each room 35
and the amount and quality of radiation reaching the walls determined.

At the same time, the workload was automatically recorded by means of an electronic integrating device developed specifically for the purpose. The results of the study, which was sponsored by the Atomic Energy

Commission, have shown that the actual X-ray exposure of the walls is about one-tenth that assumed. These results would therefore permit a substantial saving in the lead or other protective materials used in the

construction of this type of installation. National Photoneutron Standard. A new determination was made of i the emission rate of the Nation's primary standard photoneutron source. I For this purpose, an absolute calibration method was developed which is ! more precise and more easily performed than most existing techniques.

As a result of this work, the emission rate, or "(?"» previously established

for the standard has been confirmed and the accuracy of the measurement

increased.

The primary photoneutron standard is a radium-gamma-beryllium source that produces neutrons by the interaction of gamma rays with

beryllium. The source consists of 1 curie of radium bromide in a platinum-iridium capsule that is placed in the center of a beryllium sphere

4 centimeters in diameter. Because the capsule absorbs the alpha

particles from radium and its decay products, only gamma rays can enter the beryllium sphere. A secondary photoneutron standard, similarly

constructed and calibrated relative to the primary, is available to other

laboratories for comparison measurements.

The development of nuclear reactors has made possible a widespread

increase in neutron irradiation research. Asa result, a need has developed

for reliable standards to calibrate accurately neutron thermal fluxes and ( to measure neutron yields. The Bureau is engaged in a program to provide such standards and to establish improved methods of neutron measurement. The present recalibration was initiated partially as a result of

the wide discrepancies revealed by international comparisons of neutron

standards.

Low-Energy Electron Scatter. Considerable progress was made during

the year in the Bureau's studies of electrons scattered by passage through

thin films of matter. The results are applicable to the study of radiation | effects of interest in biophysics and medical research, and have a direct bearing on the performance of electron microscopes. The program also j contributes to better understanding of the solid state physics that underlies the operation of semiconductors and transistors, and the process of F secondary electron emission which is essential to the operation of many

types of vacuum tubes. Using electron beams in the range to 150 kev, the experiments have

concentrated on the scattering losses below 100 ev due to single inelastic i I collisions. Data were obtained on the distributions in velocity and

direction of electrons scattered by a large number of substances. Im-.

portant improvements were made in experimental technique and in the

36
Apparatus used in electron-optical study of gas flow at extremely low pressures

(p. 32). Insert: Obtained with this apparatus, shows dark field image of cadmium atomic beam at pressure of 0.003 mm of Hg. Bright spot above

beam is incidental background.

design of apparatus, especially the instruments used for determining the

velocity distribution of scattered electrons. These experimental studies

are supported by the Atomic Energy Commission and the Office of Naval

Research. At the same time, the Bureau itself is sponsoring a number

of theoretical studies of the scattering process.

2.5. Chemistry

A wide range of fundamental and applied research is carried on in physical, analytical, organic, and inorganic chemistry. This work embraces investigations of analytical methods, separation and purification

of substances, electrodeposition of metals, electrophoresis and light

scattering by colloidal particles, growth of crystals, polarographic studies,

labeling of carbohydrates with radioactive carbon, and developing electric devices for gas analysis, spectrometry, and thermochemical measurements.

Most of the Bureau's standard samples, critical in industrial quality

control and in research throughout the Nation, originate in the chemistry

laboratories. Rare-Earth Elements. Significant progress was made in separaling the

rare-earth elements from one another by ion-exchange techniques, based on the differential retention of metal ions on the surfaces of certain resins. Nearly all of the rare earths were refined to a high degree of purity,

praseodymium and neodymium to 99.99 percent. The highly purified

37
elements are for use in fundamental research on spectral properties,

hyperfine structure, isotope shift, and X-ray diffraction. In the course

of this work, an automatic cutoff valve and a collector were developed

for use with ion-exchange techniques. The collector, a bed of resin, removes the rare earths quickly from dilute effluent solutions and recovers

the metals in concentrated form.

Dielectric Constant of Water. The dielectric constant of water is an

important physical quantity entering numerically into basic equations.

However, discrepancies amounting to 1 percent or more exist in the best

data previously reported for this constant. During 1955 the Bureau

redetermined the dielectric constant of water by improved methods to an

accuracy of 0.1 percent or better over the range 0° to 100° C. The

dielectric constant of heavy water was also determined over the range

4° to 100° C. Acids and Bases in Nonaqueous Solvents. In a program sponsored in part by the Department of the Air Force, further insight into acid-base

behavior was gained by systematically investigating nonaqueous solve nts. Such solvents are constantly increasing in uses and multiplying in number.

Knowledge of their acid behavior is important in the petroleum, food, and

drug industries; in understanding physiological processes; in the manufacture of chemical compounds; in chemical analyses; in electrodeposition;

and in many other areas of science and industry . A puzzling aspect of acid behavior has been a lack of constancy in the

order of relative strengths when certain nonaqueous solvents are substituted for water. Systematic investigations are revealing the relation- ship between the structures of individual acids and their behavior in different kinds of solvent. In this work, use is made of a special indicator

dye developed at the Bureau and now commercially available. Thermochemistry. Determination of the heats of formation of chemical

substances is the primary method for obtaining precise values for the

binding energies in molecules and the variation of energy content with

molecular structure, such as occurs in isomeric substances or in a homologous series of organic compounds. Thermochemical data are also required

by engineers for determining heat balances in chemical-process plants and

calculating reaction equilibrium constants needed for process design and

development. During the past year, measurements on cis- and trans - isomers yielded information on the steric effects in substituted hydrocarbons. Measurements on several acyl peroxides provided data on the

energy of formation of the various acyl radicals and the strength of the

0-0 bond. Survey reports summarizing the available thermodynamic

properties of the alkali metals, halogen compounds, and boron compounds were also prepared and published. Investigations of the heats of

formation of various boron hydrides and other boron compounds are in progress.

38
One of 22 medical X-ray rooms surveyed by NBS to compare actual radiation

present with recommended safe levels. Pocket-size ionization chambers

suspended from walls and ceiling measure intensity of radiation reaching

those points. Duration and quality of radiation were also recorded (p. 35). Analytical and Physical Chemistry. Improved analytical methods were

developed for controlling the composition of ceramic dielectrics used in proximity fuses. Such dielectrics contain barium titanate, lead titanatezirconate, and other complex combinations or compounds. Developed

for the Diamond Ordnance Fuze Laboratory, the procedure involves the

separation of barium from strontium, titanium from zirconium, and a number of other elements from one another. In many cases, the determination of lead and cadmium in spelter and

zinc-base alloys is most conveniently and accurately performed by polarographic methods. A procedure was developed for the polarographic

determination of cadmium and lead in zinc-base alloys which involves

separation of these metals from the zinc by electrolysis at controlled

potential using a mercury cathode. By this procedure as little as a few

ten -thousandths of a percent of cadmium and lead can be determined.

Measurements of dielectric loss were made with resonant cavity tech- niques on methane, ethane, propane, ra-butane, isobutane, isopentane, and

neopentane up to pressures that approached the saturation pressure. Sig- nificant loss attributable to the presence of small permanent dipole moments

was found in propane, isobutane, and isopentane. The results yield important information concerning the molecular structure of these compounds,

especially with regard to polarities and bond angles.

A comprehensive investigation was continued on methods for analyzing

the new complex heat-resisting alloys used in the aircraft industries. At

39
the request of the Atomic Energy Commission, methods were developed

for analysis of sodium and potassium borohydrides and platinum-uranium

alloys.

Special Investigations and Developments. A simple, compact oven that

stabilizes the temperature of quartz crystals for precise oscillator frequency

control was developed for the Army Signal Corps. The oven utilizes the

heat of fusion of an extremely pure organic compound—p-dibromobenzene—to hold the oven temperature within 0.01 degree of 87.31° C. The special-purpose oven eliminates the need for much of the complex

equipment ordinarily used to stabilize crystal temperature in oscillator

circuits. The oven can also be used wherever a simple, compact thermostat for close temperature control is required.

Ether peroxides have been prepared rapidly in appreciable amounts by

irradiation of ether with ultraviolet light in the presence of oxygen. These

peroxides appear to be identical to those formed in ether during storage

and can thus be used to study their explosive and other properties. Ion -selective membranes have promising possibilities for increasing the

efficiency of various electrolytic processes for desalting sea water. Results

from initial work for the Department of the Interior indicate the possibility of obtaining membranes with a very high positive charge. If these

membranes can be modified to have sufficient mechanical strength, they

will provide a valuable material for biological and other studies as well as

for Interior's saline -water program.

Molybdenum possesses considerable structural strength at elevated

temperatures at which steel loses most of its strength. Molybdenum

would thus be useful for the turbine blades of jet engines were it not for

its ease of oxidation, which becomes serious above 800° C. Numerous

methods of protecting molybdenum have been explored, but the types of

protective coatings are limited because they must not only be oxidation

-

resistant and nonporous but also ductile. One of the chief problems is to make such coatings completely pore-free. Even the most minute imperfections can cause the molybdenum beneath a coating to form a volatile oxide and completely disappear within a few hours. During the

year a process was developed for the Navy Bureau of Aeronautics for electrodeposition of protective coatings consisting of a layer of chromium

1 mil thick followed by a nickel coating about 7 mils thick. These coat- ings have afforded molybdenum protection in excess of 1,000 hours at 1,000° C and 300 hours at 1,100° C. It is now feasible to make service

tests of molybdenum turbine blades having these protective coatings.

2.6. Mechanics

Basic to the Bureau's program in mechanics is the development, improvement, and maintenance of standards and the development and eval- uation of techniques for the measurement of a large variety of mechanical

quantities. These include volume capacity, weights and other forces,

static pressures, the flow of liquids and gases, vibration amplitudes, and

40
the speed, attenuation, and intensity level of sound. To provide fixed points for comparison and otherwise to supplement these basic activities,

precise determinations are made of physical constants and properties of

materials, such as density, viscosity, and sound-transmission characteristics. In addition, fundamental research is performed in the mechanics

of solids and in fluid dynamics.

A large part of the Bureau's work in mechanics during the past year has

been in direct response to technological trends toward higher speed, power,

and thermal efficiency. The increased vibration that often attends higher

speed and power, for example, has led to the evaluation and calibration of vibration pickups and the study of special pickups that may be suitable

as secondary standards in other laboratories or in the field. Similarly,

the sudden pressure changes occurring in the combustion chambers of

modern engines have required a study of the behavior of pressure pickups

under the new conditions. The possible damage to hearing from the in- tense noise of jet aircraft has led to the study of hearing loss and its compensation by hearing aids, and to the more accurate measurement of

sound levels generally and the calibration of sound-level meters over a wider range of frequencies and intensities. Much attention has also been

given to the calibration of strain gages and to the development of thin

evaporated films whose resistance would change in proportion to strain at temperatures up to the highest expected in jet engines and other

machines operating at high temperatures.

The advance toward higher speeds in aircraft and missiles lends in- creased importance to the Bureau's long-term studies of turbulence, which

controls the frictional drag on objects moving through the air. It has also increased the demand for calibration of the electronic dynamometers used

to measure engine thrust in thrust stands. The control of fuel flow for

aircraft engines and the efficient combustion of the fuel-air mixtures in the engine is under constant study for the Department of Defense to develop standards and specifications in this field. The effect of high

temperature on the production of creep in structural material and in

joints is another serious practical problem that has been studied.

Vibration Pickups. In determining the effect of shock and vibration on certain types of equipment, it was necessary to measure the vibration

of fairly flexible sheets of plastic or metal. Commercially available

vibration pickups were found unsuitable for this purpose because they were

too large, heavy, and expensive. Simple vibration pickups were therefore

developed in an investigation sponsored by the Diamond Ordnance Fuze

Laboratories. The NBS pickups are much smaller and lighter than commercial models, although their sensitivity and frequency range are comparable. They consist of a barium titanate disk and a brass mass ce- mented together with a conducting epoxy resin and attached to the vibrating surface with a thermoplastic resin. The pickups are z/\% inch in diameter, weigh 0.6 gram, and have an output of about 1.5 millivolts per gram and a capacitance of about 100 picofarads. The first resonance oc- 41
Methods of evaluating neutron sources. Left: An indium foil is inserted into pile containing neutron source; foil is later removed and its beta-ray

activity measured. Right: A dip counter measures the activity of a manganese sulfate bath that has been irradiated by the national photoneutron

standard. This permits calibration of the standard to within 2 percent

(p. 36).

curs above 90 kc and the transverse response is about one-tenth the axial response. Electrical shielding is provided by a coating of silver paint over a coating of insulating paint. Pressure Measurement. Interest continues to increase, both for in- dustrial processes and for military application, in precise measurements

of pressure, particularly at very high and very low pressures. During

the year further attention has been given to improved measurement and

calibration of very high pressures, both static and transient. In the field of static pressures, steps were taken toward the ultimate construction of

a 200,000-psi dead-weight piston gage. Following the issuance of NBS

Circular 558, "Bibliography and Index on Dynamic Pressure Measurement," the current state of the subject was examined once again; and,

under the sponsorship of Ballistic Research Laboratories, Aberdeen Proving Ground, preliminary investigations were carried out on high-pressure

dynamic calibration methods.

At the other end of the scale, improved measurements of low pressures (corresponding to altitudes above 80,000 feet) are needed for instrumentation of high-performance military aircraft. Under the sponsorship of the

Air Force, a new pressure standard covering the pressure range up to

2 inches of mercury was completed in preliminary form. This instrument

incorporates modern techniques for precise sensing of the height of mercury columns and promises to provide a standard having the necessary high accuracy. 42
Forces Produced by Waves. Because of the importance of wave action on engineering structures and on the design of ships, a continuing program

of wave research has been under way at NBS supported principally by

the Office of Naval Research. An investigation of forces exerted on

cylinders and plates exposed to sinusoidal currents, such as are produced

by continuous waves, was recently completed. A similar investigation

of the forces on cylinders in the path of a solitary wave is now under way.

Origin of Turbulence. Another step forward has recently been made

in solving the puzzling question of the origin of turbulent motions occurring near the surface of bodies moving through air or water. These

motions remove the fluid (air or water) that would otherwise be carried

along with the body, and thus simultaneously remove energy from the

body with a resultant increase in surface friction. They also increase

the rate of heat transfer and therefore increase the amount of heating that

occurs at supersonic speeds. The question, when and how turbulence

begins, was partially answered about a year ago when it was discovered,

in the course of an investigation sponsored by the National Advisory

Committee for Aeronautics, that turbulence originates on a surface at

isolated points and develops as growing spots. A continuation of this investigation has now revealed that the points occur where a wave motion

in the laminar flow becomes unstable. The instability has been studied

by producing waves artificially and controlling the amplitude and fre- quency at will. An initially plane wave front has an inherent tendency

to become irregular, developing points of high amplitude. At these

points high-frequency oscillations set in, and these constitute the beginning of a turbulent spot. This finding has an important bearing on the

theoretical as well as the practical aspects of the problem. Although numerous important questions remain to be answered, this constitutes a

significant step toward the solution of the turbulence problem, which is important in the science of flight and vital to the attainment of sustained

speeds many times that of sound.

Culvert Hydraulics. It has been estimated that approximately 10 per- cent of the cost of multilane -highway construction, amounting to several hundred million dollars per year under the present construction program,

is required for culvert installations. The high costs of modern culverts make it imperative that the most efficient installation be used and that

the water-carrying capacity be accurately known. About 2 years ago, the Bureau began a laboratory study of culvert performance for the

Bureau of Public Roads. The aim of this investigation is to establish

design criteria and to develop improved culverts of nonrectangular cross

section. The principal problem arises from the fact that conventional culverts do not flow full even when the entrance is completely submerged. The)

will, however, change over to full flow after some considerable depth of submergence, depending on inlet shape and other factors involving a complex inter-relationship between hydraulic and pneumatic processes. 408368—57 4 43
It has been found for long culverts that the regime change from part-full to full flow is controlled for a particular inlet by such different physical

processes as hydraulic jump, strength of vortex action over the inlet, air entrainment in the inlet and culvert barrel, and turbulence of the approach

flow. Performance characteristics have been determined from model

studies of a variety of conventional inlets under various conditions. The

results have not only yielded presently needed information, but more

important, have provided the necessary insight into the factors controlling

efficient operation to form the technical framework for improving the design of culvert inlets. Creep of Aircraft Structural Joints. Most of the major problems asso- ciated with the attainment of higher speeds for aircraft and missiles

result from the effects of aerodynamic and jet-engine heating. One

such effect is creep, the phenomenon of continuously increasing deformation under constant loading.

Although considerable effort has been expended toward determining

the creep properties of materials, relatively little research has been con- ducted on the creep behavior of structures. To provide data in this field, an investigation was undertaken concerning the creep and creep -rupture

testing of riveted, bolted, and spotwelded joints of aircraft materials

under constant loads and temperatures. From the results of these tests, which are supported by the National Advisory Council for Aeronautics,

methods were developed for predicting the deformation, the mode of

rupture, and the time-to-rupture for structural joints in creep. These

methods are based upon the creep properties of the materials of the joints in tension, bearing, and shear. In another phase of this work, tests were begun for creep in joints

subjected to cyclic changes in temperature and load. These tests provide

a closer simulation of actual flight conditions, in which load and temperature are continually affected by speed, maneuvers, and altitude. The

test results obtained to date suggest that a conservative estimate of the creep behavior of a structural joint under cyclic conditions of temperature

and load can be obtained from the creep properties of the materials of

the joint under equivalent cyclic conditions.

Vibration of Telephone Wires. As a horizontal wind passes over a wire,

distinct vortices are formed in the wake. The vortices subject the wire

to an alternating vertical force at a frequency that depends on the wind

velocity and the diameter of the wire. This force can cause severe vibrations if the frequency of the force is near one of the transverse natural frequencies of the wire. The vibrations, sometimes heard as a "singing" of the line wires, have caused structural failures at the points

where the wire is tied to insulators on the telephone pole. Because these

failures increase the cost of maintenance of telephone lines, the Rural

Electrification Administration requested the Bureau to conduct laboratory

tests that subject telephone wires to this type of vibration. In the tests, which are run for 100,000,000 cycles at approximately 0.125 inch double

44
Diagram (left) shows one of the methods of determining the velocity distri- bution of electrons scattered by thin films. In the actual instrument

(right), the velocity spectrum is automatically recorded (p. 36).

amplitude and 200 cps, the vibration is automatically maintained at exactly the desired natural frequency even when frequency changes occur

as a result of changes in temperature and other factors. Tests were made

on several different types of ties and on REA standard tie No. 163. The

ties were used with steel and copper-coated steel wires to determine the wear that occurs between different parts of the tie. The test results have

been of assistance to REA in the development of a suitable "pretie" type

of tie. A pretie tie is superior to other types because its initial cost is less, it is tied before it is placed on the pole, and it need not be cut off when the line is resagged.

High-Temperature Strain Gages. In recent years the use of remotereading strain gages for studying the properties of materials and behavior

of structures at normal temperatures has become common procedure.

The gages most frequently used consist of fine wire or foil resistance ele- ments, which are attached to the surface of the structure by means of

adhesives. Because the properties of both the resistance material and

the adhesives change with temperature, the normal-temperature relation- ship between change in resistance and strain may no longer hold at elevated temperatures. Furthermore, the gage material may become

unstable or fail completely when subjected to the high temperatures and

rapid temperature changes that are encountered, for example, in aircraft 45
engines and reactor components. Considerable effort is now being ex- pended to develop resistance strain gages, similar to tbe normal-temperature ones, for use at temperatures up to at least 1,600° F. Because the

materials, manufacturing methods, and users' techniques are different from those developed for the more familiar room-temperature gages, the

characteristics of these gages must be determined at the temperatures at which they will be used. A critical evaluation of these high-temperature

strain gages is necessary in order that the gages currently available may

be used with a full understanding of their limitations. Such an evaluation

is also necessary if the further development of these gages is to proceed

rapidly.

Under the sponsorship of the Navy Bureau of Aeronautics, the National

Bureau of Standards is establishing facilities for the comprehensive evaluation of remote-reading strain gages at elevated temperatures. A partial

evaluation of four types of gages has been completed for temperatures

up to 600° F, and the results have been made available to developers and

users of such gages. Milk Meters for Trucks. A study was made for the Department of

Agriculture of methods being used to measure the flow of milk from the

farmers' tanks into pickup trucks. Several methods were analyzed and

two commercial meters were tested in the laboratory. It was demonstrated that air in the milk lines presents the major obstacle to accurate metering and that components now available from manufacturers are adequate, provided that the systems of measuring are improved.

Jet-Engine Controls. Safe and successful operation of aircraft gas tur- bines and jet engines depends largely on operation of control devices that

generally are actuated by instruments measuring the temperature of the

hot gases of the systems. When the output of an engine is increased by

increasing the fuel rate, controls act to limit the temperature rise to a value that will avoid damage to engine parts. Accuracy, speed of re- sponse to temperature changes, and durability under conditions of engine

operation are necessary properties of temperature-measuring devices used

in jet engines.

A survey has been made of commercially obtainable thermocouples

used in jet engines to determine their performances under conditions of engine operation. For example, the effectiveness of various coatings

applied to thermocouples in improving durability has been determined.

Because the need for faster response of the measuring element is becoming more urgent, a number of methods for achieving this purpose have been

examined. As a result of the higher temperatures attained in afterburners

and ramjets, observational data have been obtained for a reference table on the high-temperature iridium versus iridium-40%-rhodium-60% ther- mocouple. Observations have been completed for temperatures up to 2,500° F; the complete table will cover the range up to about 3,700° F.

46
A polarographic method was developed that will determine as little as a few

10-thousandths of a percent of cadmium and lead in zinc-base alloys. The

metals are separated from the zinc by electrolysis at controlled potential

using a mercury cathode (p. 39). As a consequence of the complexity of the thermocouple systems in aircraft, provisions for breaks in thermocouple circuits must be made.

Special connectors are used at the breaks, and if the connectors are not

properly designed and constructed, serious errors in temperature indications may result. Equipment and a method for evaluating performance

of these connectors have been proposed and have been accepted by the

sponsor, the Wright Air Development Center, and by industrial organizations in the field. Jet-Engine Combustors. Under sponsorship of the Navy Bureau of

Aeronautics, a gas-turbine combustion chamber was developed which

employs a control on the quantity of primary air, internal vaporization

of the fuel, a ad injection of the vapor and stabilization of the flame across the entrance plane of the primary zone. Maximum capacity of this chamber is about 50 percent greater than that of conventional chambers,

but combustion efficiency is about the same. Because combustion

efficiency appears to depend on the degree of mixing of the primary air and fuel, a new combustion chamber was designed and is being tested in an attempt to increase the efficiency as well as the capacity.

The effects of adding hydrogen to the zone of flame stabilization in a burner simulating conditions in a ramjet have been determined. Maximum altitude for stable combustion is increased, and the maximum velocity of stable combustion at a given altitude is increased about 100 per- 47
cent. Schlieren photography has heen used to determine the path of the

additive in an effort to understand its influence on the stabilization process.

2.7. Organic and Fibrous Materials

The Bureau conducts basic and applied research on a variety of natural

and synthetic polymeric materials, including rubber, textiles, paper, leather,

and plastics. These materials are composed of very long, chainlike molecules formed by the process of polymerization. Many of their useful properties depend upon the size, shape, distribution, and flexibility of

their molecules. To advance fundamental knowledge of these industrially

important materials and thus aid in their efficient utilization, the Bureau

investigates the mechanisms involved in forming polymers, their consti- tution, molecular structure, and properties. The basic data thus obtained

are of value not only in developing new commercial polymeric materials

having specified properties, but also in devising techniques for evaluating

those materials that are already in use. During the year, for example, basic research studies provided information on such topics as thermal degradation of rubber and plastics as a function of molecular structure, specific heats of collagen and leather,

compressibilities of long-chain normal hydrocarbons, stability of record

papers, and stress-strain relationships in yarns subjected to shock loading. In other projects, test methods were developed for direct determination

of dynamic bulk modulus, evaluating abrasion resistance of organic coatings, chromatographic analysis of collagen, snag testing of coated fabrics and plastic films, and measuring flexibility of shoe -upper leather. Signifi- cant contributions were also made to knowledge of the properties of dental

materials in research conducted in cooperation with the American Dental

Association and the Federal dental services (Army, Navy, Air Force, and

Veterans Administration).

Dynamic Bulk Modulus of Polymers. A method for measuring dynamic

bulk modulus was developed to investigate the properties of polymers in the transition region between the rubbery and glassy states. The sample

plus a confining liquid is placed in a small cylindrical cavity made by

clamping together two steel blocks. Two piezoelectric crystals act, re- spectively, as a generator of volume velocity and a detector of alterna ting

pressure. Provided the wavelength of sound in the confining liquid is large compared to the dimensions of the cavity, the pressure at any instant

will be the same throughout the cavity. The bulk modulus of the sample

can then be calculated from the ratio of the voltages of the two crystals

and the bulk modulus of the confining liquid. The apparatus can be used

over a frequency range of 50 to 5,000 cycles per second and over a wide

range of temperature. Static pressures of 1 to 1,000 atmospheres can be

superposed on the alternating pressures. The apparatus is suitable for the determination of the dynamic bulk modulus of any solid or liquid

substance.

48
Heat of Vulcanization of Rubber. It has long been known that a heat

exchange takes place during vulcanization, in which rubber combines

chemically with sulfur or some other agent. However, there has been

considerable disagreement among rubber technologists and scientists re- garding the amount of the heat exchange. In work sponsored by the

National Science Foundation, a precision adiabatic-type calorimeter was

designed, and constructed to measure this heat of reaction. The calorimeter records quantities of heat liberated over a period of a day or more.

Tests showed that the apparatus can hold a constant temperature or a constant small drift so that any normal temperature change can be known

to within a few thousandths of a degree after several days' operation of

the thermal shields. In the soft -rubber reaction, which involves only the lower percentages of

sulfur, the quantity of heat liberated was about constant per unit quantity

of sulfur. However, the reaction with higher percentages (20 to 32%) of

sulfur, which forms hard rubber, or ebonite, produced less heat per unit

of sulfur. In fact, very little, if any, heat exchange was observed for the

last few percentages of sulfur entering into the hard-rubber reaction.

This correlates very well with rubber-sulfur density changes. The density

increase accompanying rubber vulcanization is greatest for the soft -rubber

reactions, but it also approaches zero for the high percentages of sulfur in the hard-rubber reaction.

Analysis of Rubber Mixtures. A rapid, convenient method was devel- oped for determining the amount of natural rubber in vulcanizates containing both natural rubber and GR-S synthetic rubber (butadienestyrene copolymer). The procedure involves thermal decomposition of

the vulcanizates and infrared spectroscopic examination of the resulting

products. The concentration of natural rubber is measured by comparing the relative intensity of absorption bands at wavelengths characteristic of the pyrolysis products of natural rubber (11.25 microns) and of

GR-S rubber (11.02 microns). The method permits quantitative

analysis where lack of solubility or the presence of interfering fillers has

prevented analysis by other methods. The total time required is only

about 15 minutes.

Temperature Control for Mixing Rubber Compounds. Better reproducibility in compounding rubber and decreased variability from one

opera tor to another were obtained by the development of special rolls for laboratory rubber mills. These rolls provide rapid heat transfer between

the rubber and the coolant flowing through the rolls, making possible

automatic temperature control during the mixing of rubber compounds.

The temperature of the rolls on conventional laboratory mills is maintained by manual adjustment of valves controlling the flow of water or steam through an axial cavity in the rolls. Because the heat transfer through such rolls is very slow, the operator must anticipate cooling or heating requirements and adjust the valves in advance.

49
The flame calorimeter is used to measure the heats of formation of hydrocarbons (p. 38). These data are of value in calculating other thermodynamic quantities, in the study of the fundamental properties of molecules,

and in the development of industrial processes. Development of the temperature-controlled rolls was sponsored by the

Federal Facilities Corporation, Office of Synthetic Rubber, in connection

with the Government synthetic rubber program. The design includes a

well for a thermocouple temperature -sensing element near the working

surface and a cavity for mounting collector rings and brushes. A commercial electropneumatic temperature recorder -controller automatically

operates valves for controlling the temperature of the water flowing

through the rolls. This system controls the temperature of the rolls containing the thermocouple within 2 degrees F of the desired temperature

during the mixing process.

Static Charge Generation in Military Clothing. A soldier wearing rubber

-

soled shoes and a nylon-lined jacket over a wool shirt may become charged

to a potential exceeding 5,000 volts when he removes the jacket, and may

draw a sizable spark upon touching a metal ground. The resulting spark

50
may ignite gasoline fumes or dust or set off explosive detonators. These

hazards and ways of minimizing them were investigated under sponsorship of the United States Army Quartermaster Research and Development

Command. Under ambient conditions ranging from cold-dry to hotdamp, the Bureau measured charges developed by various combinations

of military clothing assemblies, and the electrical conductivities of fabrics treated with various antistatic finishes. The results of these studies will be used by the Quartermaster Corps in the design of safer military clothing.

Shock Loading of Fibrous Materials. The ability of textile yarns to withstanding high-speed impact stresses, or shock loading, is becoming

increasingly important to modern industry and to national defense. Extremely high rates of strain are experienced by airplane tire cords during

landing, by seat belts and safety lines when accidents occur, and by the

fabric, shroud lines, and webbing during the opening of a parachute. In

high-speed industrial sewing the thread is subjected to impact velocities ranging from 1 to 10 meters per second as often as 5,000 times per minute.

This results in high-frequency cyclic accelerations of the thread, which may

equal several million centimeters per second per second. Similar conditions may be attained in high-speed processing of fibers, such as carding

and combing or the weaving and knitting of yarns into fabrics. To provide design data for these various applications, the Bureau has

been making an extensive study of the behavior of textile yarns under

very-high -speed impact. Supported in part by the United States Army

Quartermaster Research and Development Command, the study seeks to determine the effects of high rates of strain on textile materials and to

relate these results to the molecular structure of the fibers and the geometry of the yarns and fabrics. In connection with this work, an instru- ment was developed for measuring the stresses and strains developed in yarns, fabrics, and films when they are subjected to transverse impact at speeds up to 150 miles per hour. The procedure is to impact a clamped

yarn segment at the midpoint and to photograph the successive configurations of the yarn by means of a camera which takes as many as 15,000

pictures in a second. The series of pictures provides sufficient data to compute the stress -strain curve. The limiting breaking velocity of a

textile material, an important measure of energy absorption under impact

loading, can also be determined with this equipment. This property, as well as stress -strain curves at very high rates of straining, was determined

for high-strength textile materials. The data thus obtained are useful to establish adequate specification requirements for the webbing of parachutes. The data also have been used to determine the minimum requirements of safety lines for different conditions of use so that loss of life may

be avoided.

Properties of Glass Fibers. Knowledge of the properties of glass fibers

is important to the growing glass-fiber-paper industry, both in improving

manufacturing techniques and in evaluating the product for new uses. In work sponsored by the Naval Research Laboratory, the chemical

51
durability, heterogeneous equilibria, hygroscopicity, pH response, dis- persal, and thermal expansion characteristics of glass fiber used in producing paper were studied and compared with corresponding properties of other types of glasses. The chemical durability of this glass was very

poor atpH values below 2, improving above pH 2; there was no detectable

attack between pH 4 and pH 8. Above pH 8 the durability again decreased. Dispersal characteristics of the fibers in aqueous solutions

followed the "critical points" indicated by the chemical durability curve. The data are consistent with the previous work in the Bureau's experimental paper mill which indicated that pH 2.9 is a critical condition for the optimum production of paper from fibers of this glass.

Mildew on Leather. Prevention of mildew growth on military leather items has been an important problem since World War II. Most tanning

agents and leather lubricants for military leathers are mildew susceptible.

Thus a fungicide must be incorporated into the leather to make it mildew

resistant in hot and humid areas. The fungicide now being used for this purpose is p-nitrophenol, but it does not meet all requirements. Better

fungicides are being sought in a program supported by the Army Quartermaster Corps.

Leathers treated with different fungicides were exposed at various

locations in the United States, in Panama, and in a tropical room at the

Engineering Center of the United States Army at Fort Belvoir, Virginia.

The results of this study show that 2-chloro-4-nitrophenol, 4-thiocyanophenol, and bis(4-nitrophenyl) carbonate are about as effective as p-nitrophenol in preventing mildew growth on leather. The study also shows

that the tropical room exposure test correctly predicts the performance

of leather fungicides under natural severe mildew-growing conditions.

Establishment of good correlation between laboratory evaluation and field performance makes time-consuming field tests unnecessary in future

evaluations of new fungicides, and thus facilitates the search for a replacement for p-nitrophenol.

Determination of Lignosulfonates in Tannin Compounds. Small

amounts (5 to 10%) of lignosulfonates are used in tannin mixtures with- out impairing the tannage; however, larger amounts act as harmful

adulterants. Thus, an analytical method for the control of lignosulfonates

in mixtures of vegetable tannins has been needed. In cooperation with

the American Leather Chemists Association, the Bureau developed such

a method based on the precipitation of lignosulfonates by cinchonine. Tests made in six laboratories with four contrasting types of commercial

lignosulfonate materials showed that the method is useful for determining

the adulteration of tannin materials with lignosulfonates. The procedure

is simple and rapid, requires no special equipment, and appears applicable

to lignosulfonates generally.

Sounding balloons. Aerological sounding balloons are used by several Government agencies to carry radiosondes into the stratosphere and to obtain meteorological data. In the past the properties of the rubber in 52
Laboratory studies on an experimental model (left) of a highway drainage

culvert provide information on which efficiency of operation depends. Main

problem is the intake of air even when inlet to culvert is well below surface

of water. At right is a closeup of a vortex of air being sucked into culvert

inlet (p. 43). the balloons have been measured by stretching the film in one direction

at room temperature. However, the results did not correlate with per- formance because in flight the rubber stretches in two dimensions at a low temperature.

Under the sponsorship of the Bureau of Aeronautics, Department of

the Navy, a new laboratory method was developed in which conditions

simulate those in flight. That is, the rubber is stretched in two dimensions at a temperature approximating those encountered in flight. Good

correlation has been obtained between the laboratory results and flight

performance when other factors, such as resistance to ozone and neck

strength, are satisfactory. The Bureau of Aeronautics has incorporated

the method in its purchase specification for aerological balloons. The

test should be very useful in plant control and in the development of new

materials for balloons.

Statistical Treatment of Test Results. In the statistical theory of fitting

straight lines to experimental results, it is common to derive uncertainty

intervals for the slope and the intercept by using the classical theory of

least squares. Recent work on analytical procedures for organic and

fibrous materials has shown that the use of joint confidence regions, also based on least squares theory, is often more appropriate and that it leads

to uncertainty intervals for any function, either linear or nonlinear, of

the slope and the intercept. Unlike intervals derived in the usual manner,

intervals based on the joint confidence region have the desirable property

of being collectively valid, regardless of their number, with a joint probability that is never less than the adopted confidence coefficient. These

53
results have been found particularly useful in the study of the accuracy

and precision of analytical methods.

Thermal Decomposition of Cellulose. Basic knowledge of the reactions

involved in the thermal decomposition of cellulose is needed in the development of new nonflammable textile materials and methods of treating

present textile materials to render them more flame resistant. It is generally considered that the flaming of cellulosic materials takes place in two consecutive steps: first, degradation of the material under the influ- ence of heat to form volatile and nonvolatile products, and second, ignition of the flammable constituents of the products, with further decomposition of the cellulose. A decrease in flammable decomposition products

is therefore desired. In an investigation sponsored by the Quartermaster Corps, it was

found that by modifying the cellulose structure or by treating the cellulose with certain materials, not only the rates of decomposition but also the

products of decomposition of cellulose can be altered. When cellulosic materials were impregnated with ordinary salt, borax, sodium carbonate,

or boric acid, they were rendered more flame resistant in that their de- composition products contained more of the nonflammable materials,

such as water and carbon dioxide, and less of the highly flammable tarry

material. Oxidized cellulose was also found to be more flame resistant than the unmodified cellulose. The modification of the chemical struc- ture evidently causes the molecules to break up differently.

Radiation Chemistry of High Polymers. When polymers are exposed to high-energy radiations, as in a nuclear reactor, important chemical changes

take place. As a result, some materials are improved, becoming stiffer, stronger, and more difficult to melt. Other materials readily deteriorate. Basic research to provide explanations for such effects is needed for proper

use of these materials (for example, as electrical insulation in atomic re- actors), for preparing specifications, and for developing better materials.

Thus far, experiments have been conducted with gamma rays from two

small cobalt-60 sources. A 2,520-curie source, at present being installed,

will be used for more intensive work. In addition, through cooperative

arrangements with other agencies, it has been possible to expose high

polymeric materials to high-speed electrons, and to the combined neutron

and gamma radiation of a nuclear reactor. A variety of organic materials in fiber and film form, as well as in the raw

chemical state, have been exposed to these high -energy radiations, and

the effects on their physical properties and chemical structure noted.

Carefully designed experiments have also been conducted to determine

the mechanism by which chemical changes are produced. For example,

recent work with deuterium-substituted organic polymers has revealed

how gamma radiation attacks polystyrene and polymethyl methacrylate.

Experiments have also been conducted to explain why some materials

degrade while other materials improve in physical properties when exposed

to gamma rays. 54
Combustion chamber designed to simulate conditions in a jet engine burner.

This equipment was used to study the effects of additives on the stability of combustion (p. 47). The schlieren photograph (insert) shows the flame

stabilized on a circular rod in a high-speed stream. Note the laminar nature

of the flame near the rod. The stripes are zones of constant gradient of index

of refraction

.

Plastic Packaging Materials. Hot-dip plastic packaging materials for precision metal parts have several disadvantages. The hot-dip coating

deteriorates during application, undesirable odors are produced, and workers are subjected to burn and fume hazards as a result of the high temperatures used during application of the coating. During the year, plastisolbased cold-dip coatings were developed for the Navy. The cold-dip

coatings overcome these difficulties and also have superior low-temperature

properties, lower application cost, and less bulk than hot -dip coatings.

Data obtained in this investigation formed the basis of a specification the

Navy prepared for plastisol coatings for magnesium anodes used to protect submarine hulls. Plastic Eyeshields. A transparent eyeshield to protect military personnel in combat areas from shell, grenade, and land-mine fragments was

developed for the Office of the Quartermaster General. This eye armor

supplements the plastic body armor already in use and provides additional protection against fatal or disabling eye injury due to flying frag- ments. The shield combines the impact-resistant properties of selected transparent plastics with the flexibility of other plastics in a laminated

structure. A relatively thick, rigid plastic is backed by a flexible plastic

layer and a film of transparent plastic. The heavy front piece absorbs the

55
impact and prevents penetration of the eye shield by the fragments. The

interlayer and backing film serve to catch and hold any secondary fragments resulting from the impact.

Plastic Springs. A practical procedure for mass-producing plastic

springs was developed in work sponsored by the Army Ordnance Corps.

Springs formed in this way from glass fiber-reinforced resin have desirable

mechanical properties for a wide range of applications. Until now plastic

springs have been little used because suitable techniques for making

springs of the types needed have been lacking.

The reinforced plastic springs have a number of advantages for special purposes. For example, they are nonmagnetic and have low electrical and thermal conductivity. They can be molded directly to dimensions i without the development of any considerable internal stress. Their high

corrosion resistance should make them of value for applications in chemical

plants and installations subject to acid fumes or to salt air. Other applications may benefit from the strength-to -weight ratios of plastics, which

are often higher than those obtained with spring-making metals. Also,

the broad range of transparent and colored materials that can be used I makes striking decorative effects possible.

Electronic Measurement of Adhesion. Good adhesion is important in the service performance of protective coatings. Reliable test methods | are therefore needed that will permit evaluation of coating adhesion in the laboratory. Expensive and time-consuming service tests may then

be reserved for only the more promising materials. In a project sponsored by the Navy Bureau of Aeronautics, equipment was developed that translates the variable stripping force obtained in the

measurement of adhesion into electrical impulses. The device then sums | these varying pulses to give a single average value that can be read directly

from either a voltmeter or a standard recorder. This development has

increased the speed and ease of operation of present testing equipment i and the precision of measurements of adhesive strength.

Crazing of Plastics. Many plastics, including those used in aircraft

j canopies and windows, "craze" or develop fine cracks when subjected to

tensile stresses for varying periods of time. Crazing impairs mechanical

properties and, in the case of transparent plastics, affects optical properties | as well. This limits the service fife of these products.

During 1956, studies were conducted for the National Advisory Committee for Aeronautics to determine the mechanism of crazing in an effort to reduce or eliminate it in plastics. Recent optical investigations of

crazed plastic surfaces, using light and electron microscopy, indicate that

crazing is not merely a cracking process but is accompanied by surface

flow. This flow results in a "pile-up" of material at the two edges of the

craze crack. The flow is completely recoverable in some cases, resulting 1 in an apparent "healing" of the crack. Actually the physical separation

remains and propably reopens on reapplication of stress. In some trans- - parent plastics, craze cracks are associated with physical impurities
throughout the material. This explanation of the crazing mechanism

should aid in the development of craze -resistant plastics, thus extending

the service life of transparent plastics.

Dental Resins. Reactions involved in polymerizing the acrylic plastic

used to make dentures, artificial teeth, filling materials, and cements were

studied. Effects of various accelerators and inhibitors and of residual monomer content were determined.

A study of the accelerating efficiency of amines on the benzoyl peroxide - initiated polymerization of methyl methacrylate showed that the reaction

proceeds fastest in the presence of tertiary aromatic amines. Decreasing

hardening time improves the indentation and recovery values of the

polymeric products. The efficiency of typical inhibitors used to stabilize methyl methacrylate against premature polymerization was investigated

by measuring their radical scavenging properties. An improved pro- cedure was developed to determine residual monomer content, which

greatly affects the physical properties of the final dental product; the new

method is based on infrared analysis of the sublimation products of the

solution of the polymer in benzene. The basic knowledge gained from

these studies, which are sponsored by the Federal Dental Services and the

American Dental Association, will be used in the development of improved dental resins for curing at room temperature.

Dimensional Accuracy of Dentures. One of the most important factors

in the evaluation of materials and methods used in making artificial dentures is the dimensional accuracy and stability of the denture. In

the past, limited information on accuracy has been obtained by observation of the fit of dentures on plaster models and by measurements in a horizontal plane between reference marks placed on the denture. To

provide more complete information, a pantographic instrument was

developed in which a comparator method is used to measure the accuracy

of dentures, impressions, and models of the oral cavity. The comparator

is so constructed that as one pointer moves over the surface of a standard

impression, or denture, a second pointer attached to a dial gage moves

over the "duplicate" impression, or denture. The dial gage indicates any

discrepancies between the surfaces of the objects being compared with an accuracy of 0.001 to 0.002 inch. Contact with the irregular surface is indicated electronically to prevent distortion of elastic materials.

Crystallography of Tooth Enamel and Dentin. The crystallography of the mineral portion of teeth and bone and allied phosphates is being

studied as part of a research program sponsored by the American Dental

Association at the Bureau. The major mineral constituents of bone and

teeth are some form of apatite, Caio(P04)6(OH)2 , mixed with a smaller

amount of calcite, or calcium carbonate, CaC03

. The verification of the presence of the calcite as a second phase and an explanation of the apparent

nonstoichiometric nature of tooth and bone apatite have been the immediate objectives of the study.

57
Laboratory studies provide basic information in developing Federal Specifications for leather fungicides (p. 52). Left: Oven at 30° C stimulates a

tropical environment for leather specimens treated with test fungicides.

Right: Using steam distillation to separate and identify leather fungicides.

Removal of the carbonate by an acid treatment did not change the

X-ray diffraction pattern of the apatite. Infrared absorption spectra

identical to that of calcite were still found in both tooth enamel and

dentin. These facts indicate that the calcium carbonate is present as a

separate phase.

Certain biological and synthetic apatites as well as certain mineral

phosphorites give X-ray diffraction patterns similar to hydroxyapatite.

However, these "apatites" often differ from pure hydroxyapatite in chemical analysis and physical and chemical properties. Lead apatite and

calcium apatite were synthesized as stoichiometric (containing combining

weights of elements) and nonstoichiometric crystalline powders. X-ray

diffraction and index-of-refraction data demonstrated the existence of

crystalline, nonstoichiometric apatite with cations missing statistically

from certain structural positions in the amount corresponding to the

chemical analysis. The better understanding thus obtained of this type

of structure and its chemical behavior may lead to an understanding of some of the factors involved in dental caries.

2.8. Metallurgy

The Bureau's work in metallurgy is concerned with the physical,

chemical, mechanical, and thermal properties of metals and alloys, and

with their behavior under both normal and unusual conditions! In

general, the objective of the program is to increase both theoretical and

practical knowledge of metals in order to provide improved materials

58
constantly demanded by science and industry. Special emphasis is placed on lighter materials and those that must meet special requirements

with respect to strength at high or low temperatures.

Constitution Diagrams. In order to understand and predict the

behavior and best use of alloys, it is necessary to have detailed constitution

diagrams that show their melting points or ranges, structural changes

occurring at various temperatures, intermetallic compounds, and solubil- ity relationships.

The demand for alloys to be used at high temperatures, in such applications as turbine buckets and automobile valves, has been met by designing

multicomponent alloys. These may contain as many as 10 chemical

elements, each of which is important to the behavior of the alloy for engineering applications in the range 1,500° to 2,200° F. Reactions

within an alloy during its preparation and use often result in the formation

of hard intermediate phases which have a pronounced effect on strength

properties. There is little information on the compositions of multicomponent alloys that define their phase constitution at specified temperatures. In order to supply information of this kind, the Bureau is making a phase

-

diagram study of alloys in the quaternary system, chromium-iron- molybdenum-nickel (Cr-Fe-Mo-Ni).

Examinations of Cr-Fe-Mo-Ni alloys that contained 70 percent of iron

and additional alloys in the Fe-Mo, Cr-Fe-Mo, Fe-Mo-Ni, and Cr-Fe-Ni

systems were completed. The phase constitution of the 70-percent-iron alloys at five temperatures were summarized in diagrams and the con- temporary Fe-Mo phase diagram was modified to show the Fe2 Mo phase. In addition, the composition of a ternary phase, not previously reported, was determined, and a standard X-ray diffraction pattern of this phase was obtained.

Differences exist in the published constitution diagrams of the magnesium-zinc alloys. Because of the increased interest in light alloys used

in the airplane and other industries, Wright Air Development Center has

supported a program that succeeded in resolving most of these differences. The Air Force is also interested in the constitution diagrams of magnesium

with the lanthanide series of elements because these alloys are known to have improved strength and stiffness at high temperatures, properties

essential in modern high-speed aircraft. The solid solubilities of several

of the lanthanide metals have been established.

Research sponsored by the Atomic Energy Commission on a series of

alloys of uranium with the platinum metals (platinum, palladium,

rhodium, ruthenium, osmium, and iridium) resulted in a tentative consti- tution diagram for the uranium-platinum system, and the major reactions of the other binary systems have been determined.

High-Strength Steels. The necessity of increasing the strength of struc- tural parts in aircraft and thereby reducing the dead weight becomes more

pressing as aircraft increase in size and speed. This is particularly important in military aircraft. Under the sponsorship of the Navy Bureau

4083G8—57 5 59
of Aeronautics, the Bureau has developed an ultra -high-strength steel that can be heat-treated to strengths of 300,000 lb/in.2 with sufficient ductility

and impact resistance to be used in aircraft components.

Slack-Quenched Steels. Although slack-quenched steels, i. e., steels that

are incompletely hardened, are frequently used in industry, the mechanical properties of such steels are difficult to evaluate because of the complexity of controlling the slack-quenched structures. Under the sponsorship of Watertown Arsenal, a method was developed for accurately

controlling the degree of slack quenching of impact specimens, and the

effect of such treatments was determined on the toughness of a series of

alloy steels both with and without boron. Generally, the impact strengths

of slack-quenched steels were inferior to those of the same steels fully I hardened and tempered to the same hardness as the slack-quenched steels. These differences were reduced substantially by appropriate tempering

treatments. Temper Embrittlement. Steels tempered at high temperatures fre- quently exhibit temper embrittlement which is manifested by decreased

impact toughness after slow cooling from the tempering temperature.

Boron-treated steels, important because they can be used to conserve

critical alloying elements in heat-treated steels, are susceptible to temper

embrittlement. An investigation sponsored by Wright Air Development j Center has shown that boron itself has a negligible effect upon this phenomenon but that titanium, an element present in many of the boron addition

agents commercially used, tends to make the steels more susceptible to temper embrittlement.

Titanium. Several titanium alloys have higher strength-weight ratios than many other structural materials. However, they cannot be used to best advantage until their performance is determined at different temperatures under a number of stress conditions. Work sponsored by Wright i Air Development Center showed that the tensile properties at — 196° and

+ 100° C of both unnotched and notched specimens of commercially pure

titanium and a titanium alloy containing 4 percent of aluminum and 4 i percent of manganese were, in general, impaired by prestraining in tension

at +25° C; the retained ductilities at —196° and +100° C were decreased

by the prestraining.

Mechanism of Deformation. A fundamental knowledge of the mecha- ! nism of deformation is essential for the best utilization of available metals j and alloys and the development of new materials for high-temperature

service. Numerous theories have been proposed to predict the timetemperature relationships in single and polycrystalline metals under stress, but none is entirely satisfactory. The Bureau has continued a study of the flow and fracture characteristics of high-purity copper, nickel, and

binary alloys of these elements. Creep tests were completed on annealed | specimens of 70 percent nickel-30 percent copper and 30 percent nickel- 70 percent copper alloys. The program for evaluating the short-time60
1

Experimental setup for photographing high-speed transverse impact in textile yarns (p. 51). A hammer impels a projectile at the yarn specimen

clamped on a grid system. Film frames (below) show configurations of yarn specimen during a transverse-impact test. high-temperature tensile properties of all the materials, annealed and cold

drawn to 40 percent reduction in area, was also completed.

X-ray Studies of Stresses. The performance of metals in service is frequently related to factors not always evident in measurements of bulk

properties, such as elastic after-effect, or in the observation of gross structure, such as grain size and phase constitution. One such factor is the

condition of the small crystals that compose the metal. The lattice of

these crystals is strained when under stress, but the stress cannot be dis- tributed uniformly in the metal because the elastic and plastic properties

of the crystals are anisotropic. X-ray diffraction studies may be inter- preted to give detailed information regarding the strained condition of

crystals, which is important in attempting to explain phenomena such as fatigue and stress-corrosion cracking, that are restricted in the early

stages to an individual crystal or the boundary between crystals.

61
Previous investigation by X-ray diffraction has indicated that the

strained condition of the crystals after a uniform plastic deformation could

be interpreted as resulting from a body stress, but there was no evidence

of how this stress was balanced. One theory is that the stress reflected by the strained condition of the crystals is balanced by opposite stresses in adjacent crystals of different orientation. Another is that the observed

stress occurs only in the surface layers and the balancing stress is present

in the interior. Recent experimental results obtained from measurement

of strains in ferrite crystals do not satisfy either of the foregoing explana- i tions and another has been suggested. The balancing stress is supplied bv I stresses in material in which the crystal lattice is so distorted that it does not scatter X-rays coherently. The work is being continued by measuring, i in crystals of two-phase alloys, the strains that result from differences in contraction when the alloy is cooled from an elevated temperature.

Fatigue. A study of the effect of crystal orientation on fatigue crack

initiation was completed under the sponsorship of the National Advisory

Committee for Aeronautics. In the two aluminum alloys studied, slip

bands that formed on the crystals in the pre-crack stage of the tests served I as nuclei for fatigue cracks. These slip bands were parallel to traces of

(111) planes in the crystals. It was found that of the four possible (111)

planes, the crack originated on the one having the highest resolved shear j stress, and that this stress was higher than the resolved shear stresses on

(111) planes in crystals that were not cracked. In connection with this project, a torsional fatigue machine small

enough to be mounted on the stage of a metallurgical microscope was

designed and constructed. With this machine, observations could be

made of the progressive changes that occur on the surface of the metal

during the initiation and development of a fatigue crack. Time-lapse

movies made of these changes showed at one stage of the crack development a sudden extrusion of an unknown substance from the crack. The fatigue properties of spring wire and springs were investigated

under the sponsorship of Springfield Armory. A comparison of cold- drawn music wire and an oil -tempered wire of the same diameter showed

that the fatigue properties of springs coiled from the oil-tempered wire

are superior to those of springs coiled from high-quality music-spring wire. | An investigation of the effect of shot peening on the fatigue properties of

springs coiled from small-diameter wire showed significant improvement

in both cold-drawn and oil-tempered wire springs.

A torsional testing machine with an automatic stress-strain recorder for testing small-diameter wire was designed and constructed in connection

with the work on fatigue. The data are recorded by means of an electric spark passing through a heat-sensitive paper.

Corrosion. Corrosion is estimated to cost this country more than 5 > billion dollars annually. To obtain a better understanding of the cor- rosion process, the Corrosion Research Council of the Engineering Foundation is sponsoring a study at the Bureau on the fundamental aspects of

62
A method was developed for making plastic springs from glass fiber-reinforced

resin (p. 56). First step is to soak glass fibers in resin (above, left). Next

the impregnated fibers are drawn into plastic tubing (above, right) and the

tubing wound around a mandrel (below, left) to form a helix, which is placed

in a curing oven. After curing, the plastic tubing is removed, leaving the

finished spring.

corrosion. A study of the simple system, copper -water-oxygen, has shown

that corrosion takes place at different rates on different faces of single

crystals of the metal. Other studies indicate that rates and nature of corrosion of single crystals in different media are related to the structural features of the metal. Likewise, metals corrode differently when they are 63
subjected to stress. Stress corrosion in a-brass is intercrystalline; in

/3 -brass it is transcrystalline.

Polarization curves obtained during the corrosion of plain carbon steels indicate that carbon content and heat treatment affect the rate of corrosion. Studies are under way to determine the effects of alloying ele- ments on corrosion. Studies of the corrosion of metals used in naval aircraft were made

through exposure tests for the Navy Bureau of Aeronautics. Three

phases of the project on magnesium alloys with various protective systems

have been completed.

2.9. Mineral Products

The Bureau conducts both fundamental and applied research on a wide

variety of inorganic materials. These materials are of interest to the nonmetallic mineral industries in the production of refractories, porcelains,

pottery, glasses, enamels, cermets, and cements. The primary objective

of this work is the accumulation of basic data on the properties, constants,

and behavior of these materials as an aid in advancing the technological

developments in the ceramic industries. Particular attention is given to those areas of research that are most applicable to all branches of the

industry.

Basic research during the year included such studies as the atomic

arrangement, lattice constants and related properties of three inorganic

phosphates, mechanism of the bonding of ceramics to metal surfaces,

relation between structure and ferroelectric properties of crystals, kinetics of the thermal decomposition of carbonates, phase-equilibria studies of a number of ceramic systems, immiscibility of liquids in glass-forming sys- tems, and properties of materials at very high temperatures.

Particular emphasis was placed on obtaining data on chemical, physical,

and mechanical properties of a number of refractory materials at temperatures of 1,500° C and above. Such data is required for adequate

engineering design of ceramic components in high-speed missiles, atomicpower plants, and other applications where very high temperatures are encountered. In connection with this work, special laboratory equipment was designed and constructed for studying vapor transport and related properties of materials at temperatures up to 3,500° C. Investigations at temperatures up to 10,000° C under controlled atmospheres are also possible with the recent completion of a high -current arc. High-Temperature X-ray Diffraction. Cermets, metal-ceramic combinations that withstand high temperatures, are being considered for use

as turbine blades in jet aircraft. To select suitable binders and predict

the performance of such materials at high temperatures, data on thermal

expansion and polymorphism were obtained with the high-temperature

X-ray diffraction method. This method requires only small amounts of

powdered materials for measurements and eliminates the need for fabri- cating special specimens or growing large single crystals. A special

furnace was developed to maintain the specimen at selected temperatures

64
while X-ray patterns were made. Work has been completed for the

Wright Air Development Center on the determination of the crystal structure and lattice dimensions at 200-degree intervals between room

temperature and 1,400° C. Approximately 20 compounds, including

carbides, silicides, borides and oxides, were studied.

Engineering Properties of Ceramic Materials. The Atomic Energy

Commission and Wright Air Development Center have jointly supported

a program at the Bureau to provide the data leading to more efficient utilization of ceramic materials in high -temperature applications. As a part of this program, all the room-temperature elastic constants for ap- proximately 35 materials (oxides, carbides, silicides, cermets, and inter - metallics) were determined.

The study of the plastic deformation of polycrystalline ceramic oxides

has been continued under the sponsorship of the Wright Air Development

Center. Previous investigations showed that polycrystalline alumina

and magnesia undergo creep in the range 1,000° to 1,200° C. The

results also showed that alumina exhibits strong creep recovery whereas

magnesia shows very little. To clarify this creep behavior, both alumina

and magnesia were studied over a range of stress and temperature to develop an empirical law describing creep. Young's Modulus and the

internal friction were also measured as a function of temperature up to 1,300° C for alumina and magnesia. These measurements suggest that

creep at 1,000° C occurs by grain -boundary slip in polycrystalline alumina

and by slip with the grains in polycrystalline magnesia.

The Bureau has developed an apparatus to extend the temperature

range of measurements of Young's Modulus and internal friction. A new

furnace employing stressed tungsten heater wires has been constructed

that makes measurements possible as high as 2,000° C, where the upper

limit was previously 1,500° C. Phase-Equilibria Investigations. As part of its continuing study of

high -temperature phase equilibria important in cement clinker chemistry,

the Portland Cement Association Fellowship, in cooperation with NBS,

completed a determination of equilibria in the system CaO-CaOAl2 3

- 2CaOFe2 3

. This work establishes the relation between the composition

of the important iron -containing constituents of portland cement and the

composition of the cement raw mix in this system. The results will be

of particular value to the producers of the Nation's tremendous annual

output of portland cement by making possible the more effective operation of cement kilns. Studies of phase equilibria in certain aqueous systems, essential to an

understanding of the hydration reactions of hydraulic cements, are also

in progress. A recently completed study related to the system CaOAl2 3 -Si02-H2 presents data on the variation of composition of the

hydrogarnet phase in this system with temperature of formation.

The glass-forming regions of the Na2 0-Ti02 -Si02 and the BaO-Ti02

- Si02 systems have been determined and the liquidus temperatures of

65
Torsional fatigue machine and equipment for taking time-lapse motion

pictures of aluminum undergoing fracture by fatigue (p. 62). Center: Motion picture frames from early stages of the test show slip bands that

have developed around 0.01-in. drilled hole. Right: Later frames show that

slip bands have developed into cracks. A material of unknown composition was extruded at irregular intervals from one of the cracks (Note difference in amount of dark material at A and B).

the glasses have been measured. This is a part of an investigation to study the correlation, if any, between the physical properties of glasses

and the phase equilibria in such systems.

Immiscibilily of Liquids in Glass -Forming Systems. A quantitative

study of the formation of immiscible liquids in ceramics has been under

way. Crystal chemistry principles were applied to interpret two-liquid

formation in 19 two-member and 8 three-member oxide systems. Two

methods were developed for calculating the extent of the two-liquid

formation in these systems. Results of this study are expected to contribute to a fuller understanding of the atomic structure of glass -forming

systems.

Bonding Mechanism of Ceramic Coatings to Stainless Steel. One phase

of a study of the ceramic-metal bonding mechanism showed that copper

ions have an adherence -promoting effect when they are present in a ceramic coating applied to an 18-chromium, 8-nickel stainless steel. Because this was the first observation of a metal ion improving the adherence

of a coating to a metal other than iron or low-carbon steel, the effect of

the copper was investigated as a part of the long-range study.

Copper ions in the coating appear to produce a significant increase in adherence on both pickled and sandblasted surfaces, but the effect of the

copper decreased with increased firing temperature, and with increased

firing time, for the pickled specimens. X-ray examination of specimens

66
reveals that the copper ions are reduced to metallic copper near the inter- face during firing; however, examination of sections with the metallographic microscope showed no selective corrosion of the stainless -steel surface, indicating that surface roughness is not essential to development

of a ceramic-metal bond. The amount of oxidation of the metal base,

controlled by the copper-plating reaction, is believed to be the factor that

causes the increase in bond strength when copper oxide is incorporated

into the coating.

Mechanism of Plasticity in Clays. The first phase of an investigation

of the plasticity of clay-water systems, sponsored by the Edward Orton,

Jr., Ceramic Foundation, has been completed. The evaluation of the

property-determining attributes of clays, including the identification,

characterization, and purification of small quantities of various clay

minerals, were studied. With these samples, methods for the mineralogical, chemical, and physical characterization of clays were developed and

electrodialysis, fractionation, particle-size determination, and base-exchange procedures have been established.

Physical Properties of Glass at Elevated Temperatures. In recent years

there has been an increased interest in transparent inorganic glasses for application where high temperatures will be encountered. The Wright

Air Development Center has sponsored the development of methods to study the mechanical properties of glasses over a wide temperature range. The data obtained from the study is expected to be useful to the glass in- dustry in improving the presently available glasses as well as in connection with the development of new glasses for high -temperature applications. Equipment was designed and built for testing glass at room and

elevated temperatures. The modulus of rupture and the modulus of

elasticity of glass at three different temperatures were determined, and the

elastic moduli of glasses of different compositions were measured over a range of temperatures by a dynamic method. In addition, the roomtemperature values of the elastic moduli of glasses were measured after varying heat treatments. The resulting information has both theoretical

and practical importance in interpreting the modern concepts of the

atomic structure of glass.

Standard X-ray Diffraction Patterns. Standard X-ray diffraction patterns are widely used in research and industry as a rapid means of

identifying crystalline materials. The Bureau is increasing the usefulness of this method by adding data on new compounds and improving the

older data in a program sponsored by the Joint Committee for Chemical

Analysis by X-ray Diffraction Methods. During the past year, 60 NBS

standard patterns were published. These replace about 50 cards in the

file and add data for 35 new materials. Up to the present, approximately

300 NBS standard patterns have been produced and the data published.

These replace about 600 of the original file and add data for 74 materials not previously represented.

67
Experimental Methods for Melting Special Optical Glasses. In recent years the demand for large optical elements (6-in. to 20-in. diam) of highquality optical glass has greatly increased. To supply these elements at a reasouable cost, a small experimental platinum-lined glass tank was

designed and developed for the continuous production of optical glass.

The molten glass is cast into molds of predetermined shape and size, and

cooled to room temperature in annealing furnaces. The delivery and

casting processes are sufficiently flexible so that either bar stock or blank

stock could be cast from the tank. In any series of castings, the refractive indices can be held to ±2X 10~4

. The refractive index of any one casting in a series can be held to ±3 X 10~5

. Besides this uniformity in index of refraction, the glass was free of striae and seeds. Essentially, this fulfills the requirements for high quality

optical glass.

Any large optical element must be well annealed. The Bureau has been

developing an annealing schedule that will yield glass of the highest

degree of optical homogeneity. Additional studies were undertaken to determine how much the index of refraction of a large element can be

varied by means of heat treatment with commercially practical time

schedules, and still maintain specified uniformity of index and specified

birefringence.

Crystal Structure of Inorganic Materials. The basic explanation of the

physical a ad chemical properties of crystalline materials must come from

a knowledge of the arrangement of the atoms in the crystals. Studies are under way on the crystal structure of many inorganic crystals using X-ray

and electron diffraction techniques. Of special interest are the phosphates

and borates important to the structure of such materials as ceramics, bone

and teeth, fertilizers, and detergents. Also being studied are the various

forms of silica, important not only because of their common occurrence but also because they are structure types in which many other compounds

occur. During the year four papers were published. These gave the

structure and other crystallographic data on thallium, indium, scandium,

and chromium phosphate, and the structure and stability rauges of the

three forms of gallium phosphate.

Relation Between Structure and Ferroelectricity. During the past year,

a technique for firing an NBS ceramic transducer composition, 45PbTi03

: 55PbZr03,was developed that prevents loss of PbO vapor. A study of the

effects of a number of processing variables, including method of electrode

application, purity, and grain size, on the dielectric properties of ceramic

BaTi03 was started. Electrodes applied with silver paste introduce a variation of about ± 5 percent in the dielectric constant, and ±15 percent in the loss. A loss peak at low frequencies, appearing to be sensitive to impurity content, may be related to the contact between the electrode and

the specimen.

The shapes of lines observed in the X-ray diffraction spectrum can be

interpreted in terms of the crystal size, state of internal strain, and

68
Increasing both theoretical and practical knowledge of metals provides the

improved materials constantly demanded by science and industry. Left: Quenching steel specimens from salt baths in a study that developed a tech- nique (p. 60) for forming uniform slack-quenched microstruetures. Right:

Adjusting stress-rupture equipment for obtaining fundamental data on

creep behavior of metals (p. 60) at elevated temperature.

regularity of the crystalline structure. This technique is being applied

to a very finely divided barium titanate formed by thermal decomposition

of barium-titanium oxalate. Precision X-ray patterns have been made

for such specimens prepared at low temperatures, and are now being

analyzed. Strong changes in the X-ray patterns were found to occur

after all the gross chemical changes involved in the thermal decomposition

of the oxalate are completed.

Chemical and Physical Properties of Cementing Materials. In connection

with the large cement-testing program, research is conducted upon the

properties of portland cement and concrete aggregates.

The reactions that occur during the hydration and setting of cements

depend on the thermodynamic properties of the constituents of the cement. During the past year, the heats of formation of three hydrated calcium

silicate compounds and of two calcium ferrites were determined. The

hydrated calcium silicates are potential products of the reaction of lime,

silica, and water, and the two ferrites are closely related to the iron-bearing

phase of portland cement clinker. The behavior of hydrated portland cement was studied under

hydrostatic pressures up to 147,000 pounds per square inch. Elastic constants determined under these conditions are very different from the

values determined in the more conventional ways. This difference is mainly due to the many fine pores in hydrated portland cement. Under

large hydrostatic pressures, these pores become filled with liquid; it is 69
then possible to measure the volume changes of the cement substance | itself, whereas more conventional methods measure the properties of

entire specimens. This information, together with data on other properties, will result in a better understanding of the nature of the matrix

that binds together the aggregate in concrete. The long-range freezing and thawing durability tests of concrete ag- gregates were continued. Concretes are damaged by the action of repeated

freezing and thawing; the severity of the damage depends upon the type

of aggregate, the type of cementing matrix, and the moisture conditions

present. Three aggregates, each imbedded in two types of mortar, were

subjected to four recognized laboratory freezing and thawing procedures.

Results indicate that a system in which the concrete specimens were al- ternately cooled to 0° F and warmed to 40° F at the rate of 1 complete

cycle each 2 hours, and in which the specimens were continuously sur- rounded by water or ice, gave the best discrimination in durability between

aggregates of different quality.

Laboratory Tests Versus Performance of Porcelain Enamels. A program

for acquiring service data on porcelain-enameled fixtures and articles com- monly used in the home is nearing completion. The results from standard

laboratory tests on these materials were compared with service data on

specimens installed in homes. Laboratory acid tests gave results showing

good correlation with performance data. A loss of gloss on the surface of laundry trays showed poor correlation with those treated with acid, but

good correlation with the results of sodium hypochlorite solution treat- ment. The surface wear that was most evident on some of the table -top

enamels did not correlate well with scratch-test results, but did show good

correlation with the results of friction testing.

A similar investigation to obtain detailed information on the weather

resistance of architectural porcelain enamels was started at the Bureau

in 1939. Fourteen enamel types, represented by 864 panels, were exposed

at four selected sites. In addition to enamel types that were expected to perform well, some of the types were selected because of their expected

poor weather resistance, in order to furnish a wide range of properties for correlation with laboratory tests. During the past year the panels were

returned to the laboratory and the degree of deterioration was evaluated

by gloss and color-difference measurements.

Compressibilities ofAlkaline Earth Oxides. The alkaline earth oxides comprise a system ofextremely high melting-point substances widely used in the

refractory, ceramic, and glass industries. All oxides except beryllium

oxide exist normally as cubic ionic crystals, and because of their simple

structure, are admirably suited for theoretical analyses. The compressibilities of pure oxides were determined at NBS during the past year. Results show that there is no inherent minimum in the compressibility in any binary glass studied. The individual compressibilities are extremely

small, as would be expected from the strong binding forces in the oxides. Of the materials on which data are available, only diamond exhibits a 70
Apparatus for precision measurement of electrical resistance changes and

physical dimensions of metals at high temperatures. Such data are used

in the precise determination of constitution diagrams (p. 59) that are necessary in predicting the behavior and best use of alloys.

smaller compressibility than beryllium oxide. The values for the other

oxides are somewhat larger but show an unexpected inversion between

calcium and strontium oxides. Analyses of available data show that the

inversion is probably the result of an anomaly in density occurring in both

the alkali halide and alkaline earth group VI cubic crystals at a similar

location in the periodic system.

2.10. Building Technology

The major objectives of the Bureau's building-technology program are the determination of properties of building materials and structural ele- ments and encouragement of their standardization and most effective use. Before full advantage can be taken of the kind of engineering approach

that has guided the rapid technological development of other industries,

the building profession must be supplied with adequate standards of

measurement, new testing procedures, fundamental engineering data, and

performance standards. No single industrial organization has the facilities or incentive to obtain the needed fundamental engineering data. To this end, the Bureau continues to place more emphasis upon research

and development leading to this major objective. For example, in the

field of structural engineering, a program is now under way in collaboration

with the American Iron and Steel Institute to provide basic data needed for determining proper design tensile stresses in concrete reinforcement.

Investigations for the National Research Council are in progress on the

bond strengths of masonry assemblages with both concrete masonry units

71
and clay brick, using the relatively new portland masonry cements.

Fire -protection studies include the basic mechanism of ignition of materials as a result of self-heating phenomena, and the early detection and

effective control of fires. Flame-spread behavior of a large variety of

interior wall finishes was investigated. Basic information was obtained on the mechanism of fire extinguishment, including extinguishment by

the dry-powder method. Research in air conditioning and heating was

directed largely toward (1) the study of heat-transfer phenomena of

insulation, (2) refrigeration studies for other Government agencies, and

(3) providing basic data and test methods for improving codes and standards. In the field of roofing, studies to ascertain the causes as well as the

physical and chemical processes of the deterioration of asphalt were continued. Hospital floor constructions and materials are being investigated

to find methods for reducing the explosion hazard in hospital operating rooms.

Shrinkage Stresses in Masonry. At the request of the Defense Department, the Bureau has been studying the nature of stresses in concrete masonry walls. Such walls are subject to drying shrinkage and thermal

contraction while restrained by a rigid, dimensionally stable foundation.

The elastic theory for shrinkage stresses was developed and numerical

solutions are being obtained for walls of different configurations. The

theoretical results are being checked by noting stresses in plaster and metal

models of walls. This information should be helpful to engineers in determining the spacing of control joints in masonry and the amount and

location of reinforcement.

Masonry Calking Materials. An investigation is in progress to deter- mine the cause and control of leakage through joints of the cast-stone masonry of a large Government structure. A related study is to find a calking material whose waterproofing properties will endure over a

relatively long period—at least 10 years. At the close of 1956, seventy

samples of calking materials were being tested for properties such as shrinkage, rate of hardening, adhesion, tenacity, and durability. Twenty

percent of these calkings are of rubber-base type and the rest are the con- ventional oil or synthetic-re sin compounds.

Evaluation of Hand-Portable Fire Extinguishers. With the appearance

of an increasing variety of small hand-portable fire extinguishers in recent

years, a critical review of the accepted methods of evaluating extinguishers

has become essential. A study to determine the relative merit of standard

fires for extinguisher testing and the effect of ambient variables on the

tests has been recently completed for the Coast Guard. Attention was

directed particularly to fire hazards, primarily fires in flammable liquids,

that are likely to develop on small motorboats. Tests made with three

fires of increasing severity appear to provide a satisfactory qualitative

evaluation of extinguishers intended for use on fires in flammable liquids.

Results indicate that quite large variations in ambient conditions during

72
the tests did not give statistically significant differences in extinguisher

performance.

Mechanism of Fire Extinguishment. Extinguishing flammable-liquid

fires by means of dry powders has proven highly effective. The action has

been explained as the release of carbon dioxide from sodium bicarbonate,

the principal component of commercial dry -chemical extinguishing agents.

However, considerable evidence indicates that this is not the explanation,

because experimental fires have been extinguished with a variety of dry

powders that do not release carbon dioxide. Only small concentrations

of the materials are required; their effectiveness cannot be explained merely on the basis of excluding oxygen, diluting the atmosphere, cutting off the

fuel supply, or blowing out the fire. Optical measurements on the dis- persed powder and radiation measurements made during extinguishment

showed that the energy radiated from the flame to the fuel is largely

blocked by the cloud of powder, and extinguishment may be partially

attributed to the shielding of the fuel from flame radiation. Considered

in the light of prevailing theories of combustion and flame propagation,

the behavior of the dry powders in experimental tests further suggests

that the interruption of chain reactions in the combustion process may

constitute another important factor in the effectiveness of these powders.

Thermal Insulating Values of Reflective Surfaces. In order to investigate

how much the insulating values of airspaces are improved by using re- flective surfaces, a research program was undertaken by a research

associateship with financial assistance from the Aluminum Company of America. One hundred and fifty -four panels insulated with reflective membranes alone or in combination with fibrous insulations have been

tested. Results of the test show that, in general, almost all of the pre- dicted insulating effects were obtained, with some exceptions ascribed to

peculiarities of the installation. Heating and Air Conditioning of Underground Structures. An investi- gation of heating and air conditioning of underground installations was

initiated for the Office of the Chief of Engineers. The various field in- vestigations and analytical studies include heat transfer into the rock mass surrounding underground chambers; heat transfer in underground

reservoirs used for absorbing heat from air conditioning equipment and

internal combustion engines; and the periodic heat flow in fresh -air -supply

tunnels or shafts. Insulated Refrigerated Structures. Heat-transmission characteristics of insulated structures can be closely predicted, provided that the insulation

is dry. However, gradual accumulation of water or ice in the walls of

refrigerated structures can cause changes in heat-transmission characteristics. These changes cannot be determined by simple heat-loss tests because the test would cause melting, evaporation, and movement of the

ice or water in the walls, roof, or floor. Therefore, the Bureau developed

a calorimetric method permitting heat -transmission measurements in mechanically cooled enclosures under actual operating conditions. This

73
High-temperature X-ray diffraction apparatus for measuring thermal ex- pansion of cermets up to 1,400° C. These materials are being considered for use as turbine blades in jet aircraft because of their ability to withstand high

temperatures (p. 64). makes possible the determination of the change in heat transmission

when, for example, trucks or trailers have been in refrigerated service for a period of time. In this method, still in prototype form, a cooling fluid

is circulated through coils in the insulated enclosure and the temperature

change in the fluid is measured. The fluid is then circulated in series through a heater with adjustable known heat input and the temperature

change is measured. Calculations of the two measured amounts of temperature change in the cooling fluid, the known heat input to the

calibrating heater, and a correction for change to specific heat, give heat

removed from the enclosure under test. Asphalt Roofing. The study of the degradation of asphalt during

weathering has continued. Using the method developed previously for the separation of asphalts into groups of similar components, the dis- tribution of components in 20 asphalts, representing domestic and foreign

sources, was determined. Changes in the distribution of components

after these asphalts were exposed 200, 400, 600 and 900 hours to acceler- ated weathering were also determined.

Equipment has been developed for collecting the gaseous degradation

products of asphalt. Work is continuing on the development of methods

for separating and identifying the complex mixtures present in the watersoluble degradation products of asphalt. 2.11. Applied Mathematics

The Bureau maintains a central applied-mathematics facility which

conducts basic and applied research and renders advisory services in the

74
various mathematical fields related to the Bureau's activities. The

services are available both to the Bureau's technical staff and to other

Government agencies. Equipped with machine computing aids, including

high-speed digital computers, the facility has played a significant supporting role in the Bureau's research and development program.

During the past year, research emphasis was again placed on statistical and numerical analysis, and mathematical physics. Special assistance was rendered to the Bureau's staff and other Government groups in these

areas and in digital computation. In addition to consulting services in applied mathematics, including mathematical statistics, extensive atten- tion was given to problem formulation and analysis and, where necessary,

to the development of numerical methods for the solution of problems on

automatic and nonautomatic computing machines. The work covered a wide range of investigations and applications in engineering and the

physical sciences. In addition, an increasing share of the Bureau's mathematical effort was devoted to applications of digital computers to problems of the type encountered in business management and operation,

sometimes referred to as "data processing" problems. During the past

year over one-third of the Bureau's computational program was in these

fields. As in previous years, the Bureau's applied-mathematics program was

strengthened by the active interest and support of other Government

agencies. Especially significant was the support of fundamental and

applied research in numerical analysis and mathematical physics by the

Office of Naval Research and the USAF Office of Scientific Research.

Numerical Analysis. The program in numerical analysis has the dual

purpose of providing solid foundations for day-to-day calculations and

carrying out exploratory work in new directions. Various studies of

interpolation and approximation were carried out. In view of the value

of rational approximations to special functions, as a means of making

them available within high-speed computers, a survey was made of this

field. A particular application of mathematical elegance and practical

value is the use of Cauer-parameters in circuit design. To make this method more convenient, a new tabulation of these parameters is being

made. The computational studies of the differential equations for nerve

excitation revealed an extraordinary sensitivity of the solution to some of the model parameters, particularly the velocity of propagation.

Experimental calculations in various fields of mathematics have sug- gested conjectures, subsequently proved correct, or suggested methods

of proof of conjectures already made. An important example of the latter

class was in connection with the spectrum of the infinite Hilbert matrix.

It was known that ir is a limit point of this spectrum, but it was un- known whether r is an actual point of the spectrum: this was established

by using monotonicity properties of the coordinates of the eigenvectors,

which were observed experimentally and then properly established.

408368—57 6 75
Experimental computation was carried out in connection with the

various partial differential equations of mathematical physics. In particular, rigorous calculations were made for the fundamental period v of

vibration of a free square plate. The calculations were rigorous in the

sense that upper and lower bounds for v were obtained: specifically,

3.5252<CV<C3.5257. Numerical work done on combinatorial analysis was found to be of value in the current program of the statistical engineering laboratory; specifically, in the theoretical investigation of partially

balanced block designs.

Digital Computation. The Bureau's Computation Laboratory provides

services to the rest of the Bureau and to other Federal agencies in the

analysis and solution of mathematical problems, especially those involving electronic computation. It also develops general-purpose techniques

of programing and coding for automatic computing machines, and publishes mathematical tables of general usefulness. For example, calculations for a table of electron-physics functions were

completed and published. Spectrum-analysis computations, heretofore

done on punched-card equipment, were successfully programed on SEAC

and established as a routine problem. The solution of a mathematical

model for depolymerization was programed and successfully run for a

large number of cases. This problem involved the solution of a large

system of ordinary differential equations. New programs for crystal

-

lographic calculations on SEAC were used successfully and have been

substituted for some phases of punch card work. In the determination

of so-called J-spacings, calculations have thus far been carried out for a considerable number of crystal types.

Computations were also performed on a continuing basis for other

laboratories of the Bureau in the following projects: evaluation of thermodynamic functions, thermometer calibrations, solution of dispersion equation for optical glass, optical-ray testing, analysis of noise measurements,

stresses in a wall foundation, attenuation of pressure pulses of finite amplitude, calculations of transmission-delay times, study of internuclear potential for H3 , ground -wave attenuation, stresses in a wall resting on a footing, crystal field effects for atoms, collision integrals used in transport theory, model Government payroll on high-speed computers,

electron-penetration calculations, and basic atmospheric data. General-purpose codes for performing various matrix operations and

for the determination of characteristic roots and vectors were brought

to a high state of perfection and put on a routine basis. They have found

wide application in problems arising in various sections of the Bureau. The general-purpose ortho-normalizing code was revised and improved.

This program is of fundamental importance in enabling multiple regres- sion analyses to be carried out in a highly flexible manner. Development

work was done on automatic coding procedures, whose purpose is to use

the computing machine itself for some of the work involved in coding.

Among others, routines were obtained for the solution of algebraic equa76
Left: Casting a specimen of experimental glass for measurement of its physical properties at high temperatures (p. 67). Right: Destructive action on concrete of hot gases at the temperature and velocity of the jet blast from aircraft. This was part of a study of concreting materials suitable as warmup, power check, and maintenance aprons for jet aircraft. tions and for the evaluation of integrals by Filon's method. Incorporation of the matrix codes into the automatic system was begun. A manual

for coding in the three-address system was completed, and a three-address

compiler system started. Work progressed on logical details for an

algebra encoder.

The preparation of mathematical tables was again an important part

of the computation program. During the past year, tables were published on radial Mathieu functions, descending exponentials for arguments from

2 to 10, and hyperbolic sines and cosines for arguments from 2 to 10. Work continued on five tables: Sievert's integral, characteristic values of

spheroidal wave functions, Coulomb wave functions, the exponential

integral for complex arguments, and modified Airy integrals. For the

computation of Coulomb wave functions, a general-purpose routine was

prepared which includes all the important ranges of the physical parameters. Statistical Engineering. The principal function of the statistical engineering program is to advise the Bureau's scientific and technical

personnel on the application of modern probability and statistical methods

in physical-science and engineering experimentation. The aim is to

assist the scientist conducting research, development, or testing programs

so that conclusions of desired scope and reliability may be attained at the

lowest possible cost under existing limitations of funds, equipment, materials, and personnel. During the year extensive services were rendered,

ranging from short informal conferences to active collaboration with proj- ect leaders for periods of several months.

77
To maintain and increase the effectiveness of this program, hasic re- search in probability theory and mathematical statistics was conducted.

During the past year, this research, geared to fit the particular needs of

NBS laboratoiies, fell into two categories: planning (design) of experiments, and methods for analyzing data. Under the first category, research was conducted on a family of experimental arrangements known as fractional factorial designs. Factorial

designs, complete or fractional, have now become widely accepted as

efficient schemes for carrying out experiments that involve many different

factors. The Bureau has developed a mathematical basis for construct- ing appropriate subsets of a full factorial design for use when the total number of combinations required by the full design is too large. Advantages of these fractional factorial designs are (1) more information per measurement, (2) savings in the volume of experimentation, (3) simple

and straightforward analyses, and (4) unequivocal interpretation of

results. During the year, 118 such designs were constructed for experiments involving 5 to 16 factors each at 2 levels. These have been brought

together in a volume now in press. This tabulation was supported in part

by the Army Chemical Corps. In many experiments it is not possible to control all factors that influence

the final results, even though these factors can be measured. One way

of making such experiments more precise is to "adjust" the final results for the effects of the uncontrolled factors; and there is a standard statistical technique for making such adjustments, termed the analysis of covariance. In the research under the second category, this technique has been ex- tended so that now it may be readily applied to all types of incomplete

block designs as well as to the more familiar balanced designs, and to those

cases where the magnitudes of the corrections for the several uncontrolled

factors are not constant from block to block. Research was also conducted on the theory and application of so-called distribution -free, or nonparametric, statistical methods. These methods

are used in analyzing experimental data with a minimum of assumptions

about the form of the frequency distribution of the measurements concerned. To a lesser extent, research was conducted on methods for the

computation of the more difficult types of statistical analyses by highspeed computers.

Mathematical Physics. The Bureau's research in mathematical physics

falls under four general categories: research in mathematical analysis

related to topics in mathematical physics, research in fluid dynamics,

research in mathematical elasticity, and research in electromagnetic

theory. In mathematical analysis related to topics in mathematical physics, a comprehensive report was prepared on the application of the quotientdifference algorithm of H. Rutishauser to the computation of eigenvalues

and eigenvectors of a matrix, factorization of polynomials, interpolation

by sums of exponentials, and determination of the residues of a mero- 78
morphic function. An extensive compilation of a table of 800 Fourier

transforms of probability distribution functions has been made and will lead to the publication of a set of tables which is expected to be of immense

use to workers in the field of statistics and probability. In fluid dynamics, an analysis was made of the fundamental basis of

two-phase vapor-liquid condensation systems. This work will aid in the

understanding and development of practical condensation devices which

have important engineering and military applications. A study was also

initiated on the mathematical basis of the use of a Cartesian diver as a weighing instrument of great sensitivity. The development of such an

instrument would be of great importance in various biological applications and in other fields where such sensitivities are needed. In mathematical elasticity, a method was developed and extensive cal- culations were carried out on SEAC to determine the stresses and dis- placements in a corrugated diaphragm. The existence of a theoretical

procedure for determining these quantities should result in large savings

in the further development of these important instruments. Thus, in the

future it should not be necessary to run a new experimental program for each new design. A routine computation should suffice to indicate the

consequences of a proposed change in design. A computational procedure was developed which will enable a study of the vibration modes of a clamped-free delta wing to be made by means of a routine calculation

using SEAC. This type of wing is now under extensive development

for use in supersonic aircraft. Studies were completed in the analysis of

elastic wave transmission through various geophysical models. These

studies are of basic importance in understanding the transmission of

earthquake waves through the earth. They also contribute to the development of analytical procedures for studying earthquakes by means of

seismographic records. In electromagnetic theory, a procedure was developed for determining the diffraction and reflection of arbitrary electro- magnetic pulses from wedges. This technique can be especially useful in antenna-design problems.

2.12. Data Processing Systems

The Bureau's data processing systems program encompasses research,

development, systems design and analysis, and technical advisory services

in both digital and analog computer technology. This program, initiated during the postwar years, originated as a result of requests from several Government agencies for assistance in evaluating the potential application

of automatic electronic digital computers to their problems and in procuring suitable installations. These studies, from which systems specifications were established, eventually led to the Bureau's program of

research and development of improved computer components and cir- cuitry and subsequently to the design and construction of SEAC. This

machine was the first superspeed automatic electronic digital computer to go

into productive operation (June 1950) for the Government. Since then,

79
The cause and remedy of expansion cracks in large concrete structures have

received considerable study. Cracks of this type, shown here in a section of a dam, result from chemical reactions of the high-alkali cements with

certain types of aggregates. Micrograph of polished cement specimen

(insert) shows the white reaction products in center of angular opal grains

which cause the destructive expansion of the concrete (p. 69). SEAC has established an impressive record of solutions for both scientific and management problems for the Bureau and other Government agencies.

The Data Processing Systems Division provides probably the most

comprehensive and readily available Government source of information

in the new and rapidly growing field of high-speed automatic data processors. The broad background and experience of the NBS laboratories

have resulted in an increased number of requests from Government

agencies who seek the Bureau's technical advisory services on high-speed

digital techniques. Areas of potential application include massive paperwork operations, control systems, simulation, and the solution of specific

technical problems.

SEAC. The experimental modification, operation, and maintenance of

SEAC has been a continuing responsibility. During the past year, development work was continued on the electrostatic memory and 1,024

words of electrostatic storage are now available. Circuitry for the highspeed perforated-tape punch was installed and the punch is now available

as an additional output device for the SEAC. In addition, the Bureau is supplementing the computer with a high-speed outscriber to convert information on magnetic wire to perforated paper tape, alpha-numeric

printers, high-speed tape punches, high-speed perforated-tape readers,

and high-speed multichannel magnetic tape handlers. A device was

designed and constructed to transcribe the information on punched card

80
to magnetic wire for SEAC input, thereby providing a convenient, rapid,

and reliable means for transcribing information directly from cards to SEAC. This instrument will eliminate the necessity of having inter- mediate steps in transcribing from cards to wire, thus increasing the

efficiency of SEAC operation.

Analog Computers. Under the sponsorship of the United States Weather Bureau and the Atomic Energy Commission, two similar specialpurpose analog computers were developed to calculate the geographical

fallout pattern of radioactivity from a nuclear bomb explosion. Both

computers were shipped to Eniwetok, Marshall Islands, and used in predicting the distribution of radioactive fallout following the explosion of nuclear weapons during May 1956. These computers were not the simulation type, but rather used the analog techniques to automatize the

problems. They were designed for (1) small size and portability, (2) low

cost, (3) eliminating the need for mathematical training in numerical

analysis or digital programing in setting up problems, (4) instantaneous

solution of the problem, (5) simple visual presentation of results, and (6) rapid problem modification.

Development of New Computers. The Bureau is developing specifications

for a large-scale pilot electronic data processor. This machine will carry out pilot runs on a wide variety of data -processing problems of special interest to other Government agencies. Because the data processor will be expected to solve problems unique in either magnitude of workload or

logical complexity, it must meet special requirements on operating

flexibility and adaptability to a wide range of problem types. A special

effort is being made to exploit the recent advances in the design of logical

systems to reduce maintenance requirements for the electronic equipment

to a minimum.

Research is also continuing on the logical systems design of high-speed

digital computers. These studies have been directed toward devising more effective means for organizing electronic components into over-all systems for carrying out computing and data-processing operations.

Development of more advanced and sophisticated logical systems struc- tures makes possible considerable increases in over-all speed and computing power without imposing corresponding increases on the performance requirements of the actual electronic components. Improved

designs have so far resulted in addition units and multiplication units

capable of operating 150 times as fast as their SEAC counterparts even though constructed essentially from the same 1-megacycle-per-second

components.

Semiconductor Devices. Several years ago, the Bureau developed a method of using the normally objectionable phenomenon of the reverse

transient in a semiconductor diode to make a high-frequency power

amplifier. This circuit was the basis for developing during the past year

a complete family of elementary circuits including flip-flops, transfer

circuits, AND-gates, and inhibitors that are logically sufficient to build a 81
Application of a dry chemical extinguisher to a gasoline test fire. Extinguishing flammable-liquid fires by means of some types of dry powders has

proved highly effective. Experiments indicate that only small quantities of the material are required (p. 73). complete digital computer. An experimental system comprising 43

stages of these circuits was built to test and demonstrate their operation.

The components were not preselected and were of types that in conventional circuitry could not be used above audiofrequencies; however, in

this system they operate at tens to hundreds of kilocycles. Practical

application at 1 -megacycle -per-second switching rates awaits the manufacture of more suitable components. This program was sponsored by the

Air Force Cambridge Research Center.

Transistor Switching Circuits. A survey of various types of high-speed

transistor switching circuits is being made. When an optimum circuit has been chosen, effort will be concentrated on developing from it a set of

highly reliable computer circuits. An instrument recently developed for

this survey automatically plots the region, in terms of two disturbing

voltages, where a flip-flop circuit is statically bistable. Although it appears that the transistor circuits may at present prices be more expensive

than vacuum-tube and diode circuits of comparable performance for computers, the transistor circuits are likely to be much more reliable. Magnetic Shift Register. A magnetic shift register constructed of small

inexpensive memory-type cores was developed under the sponsorship of the Air Force Cambridge Research Center. This register functions

reliably under large variations in operating conditions and at frequencies

in excess of 500 kilocycles per second. This circuit could find many

uses in digital equipment other than the high-speed arithmetic and con- 82
trol elements of a machine, such as in input-output devices and other

auxiliary units. Gas Diode Work. Under the sponsorship of the Naval Research Laboratory, development of circuits utilizing commercially available gas diodes

as useful computer components has continued. Several variations of

the original linear counter register were devised. Possible applications

include shift registers and ring counters. The use of rf excitation of gas

diodes as a means of switching was investigated, and incorporated in the

register designs.

Samples of a linear counting tube developed at NBS were supplied by

a private manufacturer and placed on life test. Final test samples are now being manufactured for delivery to NBS. Further information on

the characteristics of currently available gas diodes is being obtained so that recommendations can be made to suppliers for improving batch

uniformity and reliability.

Computer Circuitry Packaging. A 1-megacycle-per-second digital computer package has been completed and several prototypes have been built and tested. These incorporate some of the latest developments in high

transconductance vacuum tubes, semiconductor diodes, and printed

circuitry. The packages are much more flexible for computer applications and operate on considerably less power than previous designs.

These building blocks appear promising for future use in large-scale

digital computer designs where even greater demands are made on circuit

capabilities.

Communication Link. A magnetic tape recording system was designed

and built to provide a means for greatly compressing and expanding

the time scale of the recording. Four tape drives have been provided

which record at low speed, reproduce at high speed, record at high speed,

and reproduce at low speed. The ratio of the two tape STDeeds is 2,000

to 1. A cathode-ray beam deflection magnetometer tube serves as the

low-sireed reproduce head, and provides full output down to zero tape

speed.

Data Processing Applications Analysis. Preliminary problem defini- tion, analysis, and flow charting have been carried out for sample payroll

and accounting operations. The Bureau has examined typical datahandling operations such as sorting, file maintenance, and posting of

transaction data to master records to determine the machine operations

required in a variety of supply management applications. The reportediting problem of the Public Housing Administration, requiring the

editing of input data for consistency, has been reevaluated to determine

production run requirements. Fact-finding and analysis of information on the problems and operations of sorting and distributing mail have

been carried out in connection with a program to investigate the feasibility of mechanizing Post Office Department operations. Patent Search Studies. The Patent Office-NBS cooperative program to apply machine techniques to patent search operations is well under way.

83
The program began by orienting NBS personnel in patent search require- J ments and instructing Patent Office personnel in the use of automatic ' data-processing methods. Preliminary search routines were developed

j and plans formulated for encoding routines for experiments on SEAC J that will simulate proposed search procedures. Installation of new inputoutput equipment to increase SEAC's versatility in searching has been

planned, and the logical circuitry required to connect the commercially || procured computer accessories has been designed and incorporated into i the machine. Exploration of new ideas on the characterization of in- ' formation so that it may be searched mechanically included a siudy of

j systems suitable for searching chemical structures. Training Program. The Air Materiel Command, USAF, has under- I taken an extensive program to evaluate various types of automatic data- [ processing systems in their supply management organization. Because

it is impoitant to have an informed middle management who will support i this program, the Air Force asked the Bureau to plan and conduct a training course to acquaint management personnel with the potentialities

of automatic data processing techniques. Text, lecture notes, charts,

slides, and supplemental reading lists were prepared. This material

covers basic features of automatic data-processing systems; problem

planning, definition, and analysis; programing and coding; characteristics

of various types of equipment; trends in equipment development; areas of application; and management implications. A 6-week course for Air

Force Training Officers was held at the Bureau, and eight 2 -week and

two 1-week courses were presented to Air Force management personnel

in the field. 2.13. Cryogenic Engineering

The primary objectives of the Cryogenic Engineering Laboratory are

to obtain information needed for the practical applications of very low

temperatures and to assist industry and the national defense with problems in this special field. A project yielding data of immediate usefulness consists of basic

studies of the flow of liquefied gases through insulated pipes, and of pumps that can be used to produce high-velocity flow. A gratifying

early result of the pump study was the discovery that liquid hydrogen

is less subject to cavitation in a pump than are liquids that are more commonly used, such as liquid nitrogen and oxygen. It appears, therefore, that the fluid-dynamic design of such pumps will not be a primary

concern of the laboratory, for this can be handled by the manufacturers.

The most important contribution of the Bureau is the study of bearings,

seals, insulations, and other considerations that relate directly to the

low-temperature aspects of the problem.

A contribution to basic research is the assistance being given to the

Los Alamos Scientific Laboratory in the design and operation of electro- 84
Left: Experiment in progress on the nature of stresses in concrete masonry

walls (p. 72). Results will aid in determining spacing of control joints and

the amount and location of reinforcement. Right: Penetration test on masonry calking material. An investigation is being directed toward the

cause and control of leakage through joints in cast-stone masonry (p. 72). magnets which are to be operated at an ambient temperature of about

20° K. This offers great promise as a means of obtaining magnetic

fields of higher intensity than hitherto possible. One advantage of run- ning a magnet at such temperatures is that the resistance of the magnet

conductor (copper at present) may be lower by a factor of several hundred

than its room temperature value. This results in a corresponding

decrease of power for a given magnetic field, which in turn eases the

problem of cooling the magnet. Various investigations relating to this problem include the development of pumps to circulate liquid hydrogen

through a magnet, adhesives to space the magnet coils, and heat transfer through the liquid hydrogen flowing in the small annular channels.

The requirement for information about the mechanical, electrical,

magnetic, and thermal properties of materials at low temperatures is basic to all cryogenic design, from large-scale commercial equipment to small special -purpose laboratory apparatus. In selecting materials and

properties for study, the principal guide has been the current need for the

information. Thus the mechanical properties of glass have been deter- mined at very low temperatures for the design of windows for liquidhydrogen bubble chambers. Of more general interest is the work on

thermal conductivities of various specimens of high-purity copper. These experimental studies, combined with present theory of the solid

state, are contributing factors in producing copper of the highest electrical and thermal conductivities at low temperatures. Incidental to this study was the observation in a copper specimen of the highest thermal

conductivity ever reported for this element.

Pumps for Liquefied Gases. The initial task in the development of

pumps for liquefied gases was the design of a pumping system to deliver

85
100 gallons per minute of liquid hydrogen at a head of 163 feet, which was accomplished by modifying a commercial water pump. During

this preliminary work it was found that ordinary ball bearings, completely

cleaned, operate quite satisfactorily if they are submerged in the liquid

being pumped. It was also shown that commercial face-tape shaft

seals will seal liquid hydrogen and liquid nitrogen. Some data on the

performance and cavitation characteristics of one turbine and two

centrifugal pumps were obtained with liquid nitrogen and liquid hydrogen.

The preliminary tests indicate that liquid hydrogen is less susceptible to cavitation trouble than other liquids; theoretical analyses performed in the laboratory show that this is to be expected. Test equipment has been built for application to the long-range objectives of the pump development program. The apparatus, which evaluates

shaft seals at both room and low temperatures, measures the leakage

through the seal as a function of shaft speed and pressure drop across the seal. The bearing test apparatus measures the torque transmitted

by the test bearings as a function of speed and loading at both room and

low temperatures. The torque measuring device, which was developed

for the bearing tests, measures the desired quantity directly; the usual

devices require corrections for extraneous torques.

A new permanent pump testing facility will accommodate pumps up

to about 12 inches in diameter. Many new features have been incor- porated into this facility. A "vacuum buffer zone" attached to the top

plate permits filling the pump Dewar completely with liquid without

appreciable heat leak through the top plate. The power input to the

pump is measured with a dynamometer which cradles the pump itself, dispensing with corrections for drive losses, seal friction, and bearing

friction. A vacuum-jacketed standpipe permits the pump suction to be

continuously pressurized up to heads of 25 feet, allowing power input

to be measured with boil-off techniques even when the pump suction is pressurized. A sharp -edged orifice was installed in the pump-discharge

line to measure pump capacity after preliminary work showed that

reliable flow measurements can be made with this device. The instru- mentation permits the efficiency, performance, and cavitation characteristics to be determined as functions of speed and suction head.

Liquid-Oxygen Transfer Systems. Experimental work has indicated

that losses of liquid oxygen procured for large installations, shown by

analysis to be as high as 75 percent, can be reduced by two-thirds through

the application of conventional insulation techniques and by making

simple piping modifications. Measurements were made of transient and

steady -state characteristics of insulations appropriate for liquid-oxygen

transfer lines. These data permit the computation of thermal conductivities and specific heats throughout the range from room temperature to

liquid oxygen temperature.

Flow of Liquefied Gases. Both single-phase and two-phase flow of

liquefied gases in pipes have been studied. Calculations, based upon

86
steady-state analyses of single -phase flow, show that very-long-distance

transfers of liquid hydrogen and liquid oxygen are feasible with equipment

and techniques already developed.

Data obtained on apparatus designed to study two-phase, single-component fluid flow show that the pressure drops predicted by two-com- ponent correlations can be brought closer to the observed pressure drops

if a simple momentum correction is made. The agreement, however, is not close enough. A technique was developed to photograph the configurations of two-phase flow; it is hoped that if the flow configurations can be predicted, then valid mathematical models can be set up. For

the highest flow rates, an annular configuration exists. Therefore, a theoretical analysis of this type of flow was made. The results are being

numerically integrated so that they can be compared with experimental

data. Liquid-Hydrogen Bubble Chamber. During the past year the Bureau

has been cooperating with the University of California Radiation Laboratory to develop a large 500-liter liquid -hydrogen bubble chamber. Progress in high-energy nuclear research has been made possible largely by improvements in particle accelerator design, together with advances in the

field of particle detection. The bubble chamber, the newest of the particle

detection devices, will provide physicists with a powerful tool. Many

cryogenic problems must be solved to engineer the bubble chamber

successfully. For instance, large glass windows at low temperatures are necessary for proper observation of the bubble -chamber liquid. Methods

of rapidly superheating the liquid hydrogen are required and design of

a large refrigerator is necessary to maintain the bubble -chamber liquid

at a constant temperature.

Cryogenic Processes. In 1954 research was begun on the separation of

hydrogen isotopes by low-temperature distillation of liquid hydrogen.

Previous studies have indicated that low-temperature distillation will yield deuterium gas at a potentially low price. Results obtained during

the past year show that the separation is quite feasible, and plans are being completed for a pilot-plant installation. Studies are being continued on the technical and economic feasibility

of transporting helium at or near the liquid density rather than as a gas

at ambient temperature under high pressure. It is possible to design

storage facilities to contain the helium in liquid form for weeks without

loss and large-scale helium liquefiers can be readily engineered and

constructed.

A method for purification of helium gas at pressures from 4,500 to 10,000 psi is being developed. Large quantities of helium at high pressures are used in the rocket industry for pressurization and pneumatic

control. The helium may contain impurities such as oil, water, and

nitrogen, which should be removed prior to final use. Low-temperature

and ambient-temperature systems are being considered.

87
Services to NBS laboratories and other Federal agencies in the analysis and

solution of mathematical problems form an important part of the applied

mathematics program (p. 75). Here, for use in reactor design research by

a Government contractor, Bureau scientists are investigating methods of

solving partial differential equations on high-speed computers.

Low-Temperature Properties of Materials. In support of Atomic

Energy Commission programs at other laboratories, the strengths of

glass, copper, several copper alloys, and copper-organic adhesive laminates

have been measured down to very low temperatures. In addition, some

magnetic properties of a number of structural alloys have been deter- mined, and experiments have been performed on heat transfer from

metallic surfaces to liquid nitrogen and liquid hydrogen flowing in narrow

channels. The data obtained have been applied to the design of the

large liquid -hydrogen bubble chamber for detection of high-energy ele- mentary particles and their transformations, and the liquid-hydrogen

-

cooled electromagnet.

Measurements of mechanical and thermal properties useful in lowtemperature engineering and research have continued. Included are strengths of aluminum alloys and stainless steels, heat conductivity in a variety of materials, and flow of heat through porous insulations. A

comprehensive bibliography on mechanical properties is being published.

Copper is frequently used at low temperatures where high heat conductivity is desired. Investigation of heat conductivity in a series of

commercial coppers and copper alloys has had striking results. Several

commercial coppers have been shown to have conductivity markedly

different from what had been previously supposed on the basis of their room-temperature properties, and a specially prepared copper was found

to have a conductivity far higher than any previously reported for copper. Heat conductivity in a widely used plastic, Teflon, has also been measured.

88
Continued study has been made on the flow of heat through porous

insulations. A new insulation consisting of an evacuated mixture of

silica aerogel with aluminum powder has been prepared which has about

four times the insulating value of the powdered insulations that were

until recently considered to be the most efficient. Liquefaction of Gases. More than 25,000 liters of liquid parahydrogen

and about 400,000 liters of liquid nitrogen were produced during the

year. These materials are used primarily within the laboratory for low-temperature research and engineering development. Limited

amounts were distributed to other agencies and research institutions. Two loads of liquid hydrogen of 2,100 liters each were delivered to the

Los Alamos Scientific Laboratory in a special high-vacuum insulated

transport Dewar without loss. Three hundred and fifty liters of liquid helium were produced for measuring thermal conductivity of metals at temperatures down to 4° K, for use in crystal-frequency studies, and for use by an Air Force contractor. Shipment to California was made by air in 50-liter vacuum-insulated

Dewars. The helium and nitrogen outlets of the Dewar were sealed with

relief valves to isolate the liquid from the effects of changes in altitude,

and the outer Dewar was shock-mounted to protect against severe handling.

Two small hydrogen liquefiers (up to 45 liters per hour) have been

designed and built, and a small helium liquefier (up to 10 liters per hour)

is being built. These liquefiers provide a desirable production rate for certain small laboratory requirements. The helium liquefier uses liquid

hydrogen for precooling and is useful in laboratories having a liquid

hydrogen supply.

Modifications to the large hydrogen liquefier are in progress for improving

the ortho-para conversion efficiency and increasing its versatility of use. 2.14. Radio Propagation

The radio propagation program is carried out by the NBS Central

Radio Propagation Laboratory, which has primary responsibility within

the Nation for collecting, analyzing, and disseminating radio propagation

data and information that are of value in such diversified fields as air and

sea navigation, frequency allocation, and worldwide communications.

To carry out this responsibility, the Laboratory conducts research on the

fundamental nature of radio waves, the basic theories of radio-wave

propagation, and the characteristics of radio energy under widely varying

conditions. A network of field stations is operated from the Arctic to the tropics, and data are exchanged with other laboratories throughout

the world. Within the Central Radio Propagation Laboratory are two

divisions, Radio Propagation Physics and Radio Propagation Engineering.

The Radio Propagation Physics program involves studies of radio-wave

propagation over long distances via the ionized regions of the earth's outer atmosphere. The program includes: (1) basic research on upper

89
Special-purpose computer developed to predict the geographical fallout j pattern resulting from a nuclear explosion (p. 81). Pattern (inset) repre- sents the distribution and intensity of radioactivity on the ground, after | information on the weather and the bomb characteristics is fed into the i computer. (Explosion photo courtesy AEC.)

atmosphere physics, on the formation and disturbances of the ionosphere,

and on the interaction of radio waves with ionization; (2) study of the

characteristics of specific propagation mechanisms such as ionospheric

reflection, ionospheric scattering, and guided mode propagation; and (3) regular public service as in the prediction of long-term changes in useful frequencies for communication, in the warning of short-term disturbances

to communication, and in the collection and distribution of ionospheric

and solar data on a national and international basis. The Radio Propagation Engineering program is concerned principally

| with studies of radio-wave propagation as it affects the design of radio i systems. Thus the emphasis is on those propagation characteristics that

have a limiting effect on the ability of radio systems to perform their desired functions. For example, radio noise levels which finally limit the effective distance range of radio systems are studied on a worldwide

basis. In other recent experiments, phase variations, which limit not

only the rate of transmission of intelligence over communication systems

but also the accuracy of radio direction-finding and navigation systems,

have been measured over a variety of transmission paths. Much work

has been centered on the characteristics of tropospheric propagation and

the effects of meteorological conditions as well as other variables. Radio Propagation Physics

Upper Atmosphere Physics. Knowledge of the physical and chemical

processes responsible for ionospheric behavior is basic to an understanding

of ionospheric radio propagation characteristics. Gross characteristics are relatively predictable with present information, but many new important developments and applications involving radio propagation

depend upon a knowledge of the fine details of ionospheric behavior,

90
which can be gained only through continued fundamental research. Theoretical studies of turbulence in the upper atmosphere have shown

that whereas the density fluctuations caused by turbulence produce

fluctuations in ionization density and are of importance to radio-wave

scattering, a much stronger source of ionization fluctuation results from

the turbulence -induced transport of ions between regions of different ionization density. This theory permits an improved insight to the

mechanism of ionospheric scattering. In more recent work the turbulence transport and the resulting diffusion have been applied to the theorv

of the D layer, whose properties of absorption at low frequencies and scat- tering at higher frequencies are very poorly understood.

A theoretical study was made on atmospheric oscillation as a result of

atmospheric heating coupled with tidal forces. Satisfactory agreement was obtained from a comparison of this theory with some actual data on

observed tides at diverse levels in the upper atmosphere.

Radio Noise from the Planet Jupiter. With the discovery by Franklin

and Burke, of the Carnegie Institution, that noise signals from the planet

Jupiter can be observed, it was recognized that this provided a unique

source for observing signals from outside a planet's ionosphere and for studying ionospheric phenomena under conditions somewhat different from those on earth. Two interferometers were assembled to permit

simultaneous observations on 18 and 20 megacycles per second. Emissions from Jupiter were observed on three of the first five nights the

equipment was in operation. Observations of this emission continued

with about the same regularity until late March, when the seasonal

increase in ionospheric critical frequencies caused severe interference. In addition to the signals observed by Burke and Franklin, which were

associated with a time constant of about 1 second, a new type of signal

has been observed with much shorter time constant and occasionally of greater magnitude. Also, unexpectedly poor correlation has been observed between the signals on 18 and 20 megacycles per second. Analysis

of the distribution of the emissions with respect to longitude on Jupiter,

as proposed by Shain of Australia, has shown four distinct planetary

regions preferred for the emissions rather than the smaller number that

he found. The observations made so far are leading to revisions in theories proposed for the origin and characteristics of the Jupiter signals.

Airglow. A portion of the basic research into the physical properties

of the ionosphere is a study of the radiations comprising the night airglow

which result from excited molecules and atoms in the upper atmosphere

in the general region of 100 kilometers above the earth. Improved

and extensive observational data will lead to a better understanding of

the fundamental physical mechanisms of the upper atmosphere. The

program is a unified one for the systematic study of the night airglow,

with particular emphasis on its absolute intensity, its height, its temporal

and geographical variations, its relationship to the aurora, and its correlation with other ionospheric phenomena.

408368—57 7 91
An observing station has been established in the Colorado Rockies,

where regular observations are carried out. A telescopic photometer

has been developed which has improved spectral resolution and gives a more rapid sky coverage than was hitherto available. It is arranged to scan the sky repeatedly and automatically and to record the observed

intensity within a narrow spectral band. During last year's period of

low sunspot activity, the related magnetic, auroral, and airglow activity were all low, and it was possible to make a study of the faint zodiacal

light, because there was a minimum of upper atmosphere radiation

interference. Evidence was obtained for a zodiacal light maximum in a

direction perpendicular to the plane of the ecliptic. With the increase

of solar and magnetic activity in recent months, there has been a notable

increase in auroral activity which is evidenced by low arcs on the northern

horizon. Present studies are aimed at determining what relationship

exists, if any, between this and the airglow structure observed. Analysis

of the records has been accelerated by the use of punched-card and

electronic-computer techniques.

In cooperation with the Air Force Observatory at Sacramento Peak,

New Mexico, several nights of observations were obtained simultaneously

there and at the NBS station. A triangulation analysis of the records

shows that the height of the emission must be near 90 kilometers rather

than at the much higher height believed some years ago. As part of the International Geophysical Year program, photometers

of the improved design are being constructed for six IGY stations, and

personnel are being trained in the operation of these photometers for the IGY period.

A New Type of Ionospheric Storm. On February 23 there occurred a major solar flare with unprecedented terrestrial effects. These included

a widely reported increase in cosmic-ray flux all over the world which was by far the largest of the six recorded instances of this phenomenon.

Radio observations showed the expected communication fadeout in the

daylight hemisphere of the earth, whose association with solar flares was

first pointed out by J. H. Dellinger of NBS in 1936. In addition, a very

large increase in ionospheric absorption was found at NBS and associated

ionospheric sounding stations in high latitudes in the dark hemisphere,

beginning about 15 minutes after flare maximum and cosmic ray increase. At the highest latitudes the effect continued for at least 2 days. Such

communication blackouts are not uncommon in polar regions during

magnetic storms and auroral displays; this, however, is a clear case of

blackout without magnetic activity or aurora. This is the first clearly recognized instance of a dark hemisphere effect in the ionosphere closely following a solar flare. The observations can

best be interpreted in terms of a continuing bombardment of the earth's atmosphere by ionizing particles in the million-electron-volt energy

range which must have been present or trapped in the vicinity of the

earth in unusual quantities and for an unusually long time. These

92
Left: Output unit of a communication link designed and built for greatly

compressing or expanding the time scale for transmitting and recording

information in data processing systems (p. 80). Right: This punched-card

transcriber reads 200 standard 80-column cards per minute and converts the

data into binary code for direct input to a computer or for storage as a recording.

particles are probably the low-energy tail of the cosmic rays. There is evidence that the unusual ionization causing the absorption of radio waves was produced at an ionospheric level below the usual absorbing

region.

Trans-Atlantic Communication System Using VHF Ionospheric Scattering. The requirement for long-distance radio communication in the

Arctic, which is immune to disruption resulting from magnetic and auroral

disturbances, is an important one. Very early observations of the ex- istence of a new kind of propagation at VHF over long distances by

scattering from the lower ionosphere promised high reliability even during

blackouts of normal communications. As a consequence, a prototype

experimental "scatter" circuit was installed for the United States Air Force from Goose Bay, Labrador, to Sondre Stromfjord, Greenland.

The system was designed by the National Bureau of Standards, and was

installed and tested under NBS supervision by the E. C. Page Company,

consulting radio engineers. Very soon thereafter, a complete operational system from Limestone, Maine, to Thule, Greenland, via Goose

Bay and Sondre Stromfjord was designed and installed under NBS

supervision on behalf of the United States Air Force. This system is capable of four-channel radio teletype service of high reliability. A

number of experimental types of high-gain antenna are used, based on

design and model experiments at NBS. On the basis of operational

experience with these early VHF scatter circuits, the United States Air Force decided to extend the system across the Atlantic, using the existing

links to Sondre Stromfjord, Greenland, and extending them by way of

93
Iceland to England. NBS was requested to provide consulting, design,

and supervisory responsibility, and to contract for the actual installation,

which was done by Page Communications Engineers.

NBS, by virtue of participation in these pioneer operational applications, has been able to gather extensive data on geographical factors

affecting VHF ionospheric scattering and measurements of transmission

loss under a variety of path lengths and antenna designs, as well as to

test and observe operational performance of these techniques.

The Extreme Range of Ionospheric Scatter Communication. The ex- treme useful range of the regular propagation of VHF radio waves by

ionospheric scattering is limited mainly by earth curvature. With too long a path length there would be no part of the scattering layer visible in common from both transmitter and receiver, and because of the high

loss associated with the scattering mechanism, transmission by double

-

scattering is not feasible. Confidence in prediction of performance over paths longer than about 2,000 kilometers was limited by lack of a complete knowledge of the relative energy contributions of scattering from

various ionospheric heights, especially as regards diurnal and seasonal

variations. Also for very long paths involving extensive passage of the

VHF waves through the lower, refracting atmosphere, experimental observations seemed necessary to assess the practical effects of tropospheric

refraction and occurrences of superrefraction or ducting. An opportunity

to test a path in the critical extreme-distance range, from Newfoundland

to the Azores (2,271 km), was recognized by the existence of high sites overlooking the sea in suitable directions from both terminals. In the

test, standard-frequency oscillator techniques were used to stabilize the

transmitter, and also in the construction of special narrow-band re- ceivers. This permitted the test to be carried out with a much less expensive antenna installation. Signal strength at 36 megacycles per

second was recorded throughout the year without interruption except

for equipment reasons. The experiment demonstrated that regular

communication by ionospheric scattering is feasible at a range of 1,400

miles, provided special siting conditions exist and are properly utilized. Sporadic E. An extensive review was carried out of the existence of sporadic E transmission, and an analysis was made on a worldwide basis. A much higher incidence of sporadic E transmission had been found in experiments conducted in Japan than in similar experiments in the

United States. An analysis was therefore made of data from vertical

-

incidence ionosphere-sounding equipment and, at higher frequencies,

from experiments using oblique-incidence paths, and of operational

reports of sporadic transmission. Inspection of the 7 years of vertical incidence data from the worldwide network of ionosondes confirmed the

suspected longitude effect, in that a well-defined maximum in sporadic E

is found to exist to the south of Japan. In the temperate zone, a negative

correlation was found between magnetic activity and the incidence of

94
sporadic E. The results of this study point toward the possibility of a

terrestrial energy source for temperate -zone sporadic E, and an extraterrestrial one for sporadic E in the auroral zone. As an outgrowth of

this study, special experiments will be undertaken during the IGY to determine some of these features more quantitatively.

Automatic Data Processing. The practical application of ionospheric

and radio propagation science is seriously hampered by the great amount

of labor involved in present methods, as in making calculations and

predictions of propagation characteristics. Research in this field is like- wise hampered by the difficulties and expense of utilizing already available

data, and by the inefficiency of present methods of accumulating and

processing new data. The use of electronic computers and machine methods for processing

data offers possibilities of tremendous improvement in these directions. A computing machine, using punched cards, with possible extension to other recording processes such as magnetic tape, was installed during the

year to provide a basic tool for these numerical methods.

The first phase of the work has been to develop a systematic method

for processing the hourly ionospheric measurements of the CRPL stations. Since May, the measurements of 10 stations have been completely processed automatically. Monthly data tabulations, and tables giving statistical distributions and affording a means of finding errors, are prepared on a regular basis. These activities provide the basic steps toward a numerical representation of the ionosphere, and studies are under way on

using these methods of automatic data processing in preparing the regular

predictions of forthcoming ionospheric characteristics, and in automatizing

specific path calculations. The automatic data processing facility is also being applied to other

research activities, and has, for example, made a marked improvement

in the handling of airglow data. Data reductions formerly requiring

about 1 man-year of effort can now be accomplished in about 1 man-day.

International Geophysical Year. Although taking of data for the Inter- national Geophysical Year officially starts on July 1, 1957, several activities have already begun because of the extensive preparations required.

Six airglow photometers are being constructed, two of which will be

operated by NBS with the remainder sent to other IGY stations. A

contract is in effect for the production of 14 ionospheric recorders of a new model. The first of these recorders has been completed. Because

of the prolonged logistic lead time required, equipment has already been

sent to Antarctica for the installation of ionosphere sounding stations at the South Pole and at the Marie Byrd Land Station. Equipment for four additional Antarctic stations is presently being assembled and will be shipped within the forthcoming year. Siting studies are also under way

for the observation of ionosphere forward scatter in equatorial regions,

and for an oblique -incidence sporadic-^ measurement experiment.

95
Apparatus used to measure the thermal conductivity of materials at low

temperatures (p. 88). Such data along with mechanical, electrical, and

magnetic properties are basic to all cryogenic design, from large-scale equipment to small special-purpose laboratory apparatus.

Radio Propagation Engineering

Radio Studies of Atmospheric Turbulence. Dependable theories of

atmospheric turbulence have been developed during the past year which

are capable of explaining in considerable detail the extensive experimental

data on tropospheric forward scatter gathered primarily by the Bureau,

but also by other organizations, during the past 15 years. These advances

in theoretical knowledge were recently accelerated by an experimental

study of the variations of phase on short line -of-sight transmission paths.

Techniques have been developed for measuring phase variations at 1,000

megacycles per second with an accuracy, over 5 -minute sampling periods,

of a few hundredths of a degree and with a stability in the first derivative

of the phase of better than one part in 1012

. Measurements employing

these techniques, in addition to providing data of direct engineering value

to the designers of direction-finding equipment, have provided a remarkable insight into the physical nature of atmospheric turbulence.

Extending the Scope of the Atmospheric Radio-Noise Program. During

the past year the atmospheric radio-noise recorder developed at NBS has

been accepted internationally as appropriate for use in a worldwide

measurement program. In addition to providing continuous recordings

of the average power of the noise received on a standard antenna at 8

discrete frequencies in the range from 15 kilocycles per second to 20

megacycles per second, some of these recorders have been modified to record also the average noise voltage and the average of the logarithm

of the noise voltage. It has been shown that these three statistical

96
characteristics of the noise provide a reasonably comprehensive picture

of the physical nature of its amplitude distribution. Fourteen recorders

have now been delivered or are on order, and it is expected that two more

will be ordered shortly by the Government of India so that a good start on a worldwide program of noise measurements will be under way during

the International Geophysical Year. Propagation From a Transient Dipole Source. Among the more signifi- cant of many theoretical studies carried out during the year has been

the solution for a transient dipole source over a curved homogeneous

conductive sphere. The numerical results show the characteristics of an electromagnetic pulse propagating over the surface of the earth. The

theory has recently been extended to account for the presence of the

ionosphere by both geometrical-optical and modal techniques.

TACAN Investigation. The objective was to evaluate the coverage

of the TACAN system of air navigation and to make recommendations

for use in the common system. Charts are to be prepared showing the

coverage of a TACAN facility under various conditions, the required

distance separation among ground TACAN facilities operated on a com- mon channel assignment and on any other than a common channel assignment, and the number of channels required for a specific plan of sites and

coverage to be furnished by the Air Navigation Development Board.

Consideration is to be given to TACAN equipment as currently being

produced and to improved equipment which may be available within the next 10 years. Bench tests of current TACAN equipment initiated by NBS indicated

that system performance, especially with regard to adjacent channel

interference, was not as good as originally thought. These results necessitated consideration of a wide range of equipment characteristics. Procedures that had been formulated under this project for deter- mining the probability of service to be expected under various conditions were used for detailed calculations. These methods were designed to be

as general as possible, so that they might be applied to various ground-toair communication systems operating in the VHF and UFH regions.

Diagrams have been drawn to show the service to be expected under a

large variety of conditions of cochannel and adjacent-channel interference. The results of these studies provide a basis for determining the number

of channels required for nationwide TACAN service, an important

consideration in determining the feasibility of using TACAN in the common system.

Airborne Refractometer. This project was established to develop a microwave refractometer installation in a light, single -engine army

aircraft. The necessary characteristics were essentially high useful

sensitivity, simplicity of operation and maintenance, and reliability,

with low space, weight, and power requirements. Due to operational

problems it was important that the instrument be designed to require an absolute minimum of structural modifications of the aircraft in which

97
it was installed. The result to date is a system weighing about 35

pounds, consisting of a refractometer (7X10X12 in.) operating from a 100-volt 400-cps line and an inverter (10X6X8 in.) 28 volts dc to 100

volts 400 cps to permit operation from the airfcraft supply. The noise

figure as measured in laboratory tests is about 0.005 TV-units and the

design is such as not to require an operator in normal flight use. The

sampling cavity is mounted on a bomb rack under the wing and the

entire system may be installed on the L-20 type of aircraft without

making any structural changes in the aircraft. This project was sponsored by the United States Army Electronics Proving Ground, Fort Huachuca, Arizona.

Propagation Measurements in the Pacific Coast Region. The objective

of this project is to investigate over-water tropospheric propagation for paths both within and beyond the radio horizon in the Pacific Coast

region. This program is sponsored by the United States Naval Air

Missile Test Center (USNAMTC). The Bureau has provided technical

assistance and consultation regarding frequencies to be employed, instal- lation of transmitting and receiving equipment, recording of data in a form most suitable for analysis, and calibration of the equipment. NBS

has also provided receiving, recording, and calibration equipment,

modified for operation on 100, 244, and 394 megacycles per second.

Operation on 394 megacycles per second commenced in October 1955,

with transmissions originating on San Nicolas Island, and receiving

equipment operating on Laguna Peak (within the radio horizon), and at USNAMTC (beyond the radio horizon). Calibration and data -collecting

procedures were established jointly by the test center and Bureau personnel. Data recording is performed by USNAMTC, and data analysis

by NBS. Preliminary results for the month of November 1955, compiled

and compared with theoretical computations and estimates, have been

summarized in a report. A more thorough analysis of the data through

January 1955, including a study of space-wave fadeouts and refractive

-

index variations, has been completed and prepared for publication.

Consideration is being given to more efficient methods of data collection and processing by means of digital and punched-card equipment.

USNAMTC has initiated procurement of equipment for this purpose.

2.15. Radio Standards

In direct line with the Bureau's basic objectives the program in radio

standards is principally concerned with primary electrical standards,

measurement techniques, and properties of matter in the frequency

range from 30 kilocycles per second through the highest available micro- wave frequencies. In most of this frequency range the services offered to the Nation will be greatly amplified by the establishment of the

Calibration Center now being constructed (p. 180). In the extreme

high frequency range, standards and adequate measurement techniques

98
Automatic telescopic photometer][installed on Fritz Peak in the Rocky

Mountains for observation of night airglow (p. 91). A built-in programing

unit causes the photometer to scan the night sky continuously. Six photometers have been designed and constructed for the International Geophysical Year.

are still essentially nonexistent. In the lower frequencies, increasing

electronic applications have created a need for greatly improved primary

standards and calibration techniques.

Attenuation Measurements. To maintain an up-to-date calibration

service for high-frequency attenuation standards, which are widely used

in the precision measurement of almost all electronic quantities, the

Bureau must constantly improve its standards and methods of measurement. A new insertion-loss measuring system capable of very high

sensitivity was thoroughly investigated both theoretically and experimentally. The advantage of this system is that it reduces the output

stability necessary in both the rf source and monitor. To utilize the

advantage of this system and so gain greater measurement accuracy, rf power leakage and unstable reflections from connecting transmission

lines were minimized by devising and constructing a solid-line rotatingjoint type of line; in addition, improvements were made in the design

of the attenuation standard with regard to shielding, accuracy, simplicity of construction and ease of operation. A new standard piston attenuator was constructed and tested for performance.

Dielectric and Magnetic Materials. Accurate precision measurements of

the hf dielectric and magnetic properties of materials are basic to many

new applications of these materials in military and industrial electronic

circuits. Such measurements are also required for the synthesis of new

materials. A new automatic wide-temperature-range cavity to be used

for measuring the high-frequency dielectric properties of ferrites and

other materials was improved with a circuit to control automatically the

position of the short circuit. 99
Two permeameters were designed and constructed for measuring the

parallel reversible permeability of magnetic toroids, and a high-current

rheostat was constructed for controlling the d-c field of these instruments.

A variable length reentrant cavity for permeability measurements in the

range from 40 to 1,000 megacycles per second was constructed and placed

in operation. A half-wave variable-length cavity was designed primarily

for low loss permeability measurements in the region from 300 to 3,000

megacycles per second. A calorimeter for high-power rf-loss measure- ments in magnetic materials was completed, and the associated temperature circuits were partially constructed. Many measurements of magnetic materials were made with regard to frequency and temperature

dependence, the effects of magnetic and thermal shock, and external bias

field. This information is being incorporated into JAN specifications by

the Armed Force Services with the assistance of the Bureau. The volume conductivity of highly polarizable crystals was measured

as a function of temperature, time, and field strength. These measure- ments showed a very definite relationship between the conductivity and

the polarization state of the crystal, which should have considerable

practical use as well as yielding valuable information on the fundamental

processes of conductivity.

Frequency and Power Stabilizers for Precision Measurements. Precision

measurements at microwave frequencies require that the signal source or generator of microwave power be highly stabilized in frequency and power

level (or amplitude). This becomes very necessary if measurements are to be made as economically as possible by minimizing the need for monitoring or adjusting the signal source to obtain constant conditions of

operation. Frequency and power-level stabilization are much needed

developments for use in microwave instrumentation for the new Calibration Center. During the past year as byproducts to the microwave power and at- tenuation projects, there were two significant developments that are now

answering the need for power level and frequency stabilization in signal sources. The first is a frequency discriminator circuit using waveguide

components, the initial design being made of X-band waveguide (operating around 10,000 megacycles per second). The reference of frequency

is a temperature-compensated, tunable, cavity resonator. The present

design gives a frequency stability of better than 1 part in 100,000 over

a period of 1 hour. Although this is not unusual performance for fre- quency stability at microwave frequencies, the method has the advantage

of being simple and relatively low in cost, and has great flexibility in that it can be tuned over the entire useful band of the waveguide

components.

The second development is a power or amplitude stabilizer incorporating electronic circuitry that was originally designed for a self-balancing

d-c bolometer bridge for precision power measurements at microwave

frequencies. Modifications of this bridge have produced a circuit with

100
Mobile laboratory and antenna towers used in observing radio noise signals

from the planet Jupiter (p. 91). These observations are providing new

knowledge on the origin and characteristics of the Jupiter signals. a power stability at 10,000 megacycles per second of about 0.02 percent

per hour. The combination of this power stabilizer with the frequency

stabilizer in a microwave signal source produces a generator of microwave

frequencies that is a real boon to making precision measurements. It is planned to make extensive use of these stabilizers in equipment for the new Calibration Center. Frequency Standards and Radio Broadcast Services. Beginning in

January 1956, the standard-frequency broadcasts from the Bureau's

radio stations WWV (Beltsville, Md.)'and WWVH (Maui, T. H.) were

increased in accuracy from 1 part in 50 million to 1 part in 100 million. The stability of the frequencies broadcast was increased to 1 part in a

billion at WWV and 5 parts in a billion at WWVH. These increases in accuracy and stability were due in part to a change in the method of adjusting the time signals to agree closely with the new uniform time.

UT2, as determined by the U. S. Naval Observatory. With this new

method fixed time adjustments of 20 milliseconds are made on Wednesdays when necessary. Two such adjustments were made between

January and June 1956. Previously the time signals were adjusted by

overcompensated changes in the frequency.

Variations in the delay time of time pulses from station WWV to Boulder were photographically recorded at 15 and 20 megacycles per

second; values of one- to two-tenths of a millisecond affirmed the accuracy

of the procedures used in assessing and steering the broadcast.

A questionnaire survey concerning the broadcast of standard frequencies

and time intervals from WWV and WWVH showed that all of the broadcast was of value to many users in the industrial, communication, and

navigation fields. However, the most used parts were the standard

radiofrequencies and the time signals.

A special low-frequency antenna supported by five 120-foot poles was

essentially completed at the Boulder Laboratories and a transmitter

101
partly converted to permit the broadcast of very low frequencies. This

experimental broadcast was planned for studying the stability, accuracy, and reliability of standard frequencies in the region of the spectrum where

the transmitting medium is more stable. In work to improve the stability of crystal clocks, basic information was obtained on the characteristics of quartz resonators at liquid helium

temperatures; initial drift due to aging was reduced by a factor of more

than 10,000; the quality of the resonators was also improved.

Impedance Standards. To facilitate the calibration of high-frequency

impedance measuring instruments a set of approximately 60 impedance

standards was completed and calibrated at low frequencies. Special connectors on these standards and other instruments, with coaxial

dimensions of 0.7500 and 0.3257 inch, were developed. Much consideration was given to the choice of dimensions and to minimizing the

corrections. A taper to be used for calibrating the standards at high

frequencies was designed.

A new technique of making precision measurements of impedance at microwave frequencies in terms of standing-wave ratios or reflection

coefficients was completed. This technique permits use of sliding loads

as standards of standing-wave ratio and, in turn, provides a method of

measuring unknown loads. Use is made of a three -arm waveguide

junction with a generator and detector connected to two arms and the

standard or unknown to the third arm. Advantages of this technique

are that the waveguide junction is not critical to symmetry, or extreme

mechanical precision, nor is there the requirement of losslessness. The

technique is a definite advance in the precision measurement of standing- wave ratios in waveguide circuitry because of (1) its increased generality

and rigor of theoretical analysis; (2) the use of bolometer for detection

with accompanying increased range of linearity, because tight coupling

of detector to junction is not a critical feature; and (3) its simplicity as compared with the more conventional slotted-line technique. The

accurate measurement of impedance is important in determining per- formance of microwave equipment and matching of components for maximum power transfer. It is also a very necessary procedure in making many other microwave measurements, especially when high

precision is involved.

Microwave Spectroscopy of Gases. Continuation of the systematic

study of the microwave absorption of gases at high pressures has resulted

in the development of a very accurate technique for determining quite

small dipole moments and has shown a distribution of relaxation times

for the nonresonant absorption in gases. Further, well-known statistical and statistical-collision theories of line shape have been shown to fail in the low-frequency tails, while two-collision theories have been shown to give proper frequency dependence in this region. Information concerning

line shape is quite useful in estimating attenuation of radio waves and

102
microwaves by the atmosphere. Although nonpolar gases are not

expected to absorb microwaves, such absorption was found experimentally

and the results explained semiquantitatively as due to quadrupole

moments in one molecule inducing a dipole moment in a nearby molecule.

This new effect should be important in understanding the absorption in

liquids and highly compressed gases. Work was completed in gathering data for a revised edition of the NBS

circular on molecular microwave spectra tables, the information coming

from approximately 400 sources on a worldwide basis. Analysis of the

data is in progress. The table is valuable as a comprehensive source of

information on spectrum lines used as secondary standards of frequency

in the microwave region, for chemical analysis, as well as in the deter- mination of molecular structure. Power Measurements and Standards. Accurate rf power measurements

and standards are in wide demand by both commercial and military

groups for determining the range of rf power sources and transmitting

equipment.

Bolometer-bridge circuits of superior accuracy, wide range, and simplicity were developed to measure high-frequency power from 0.1 milliwatt

to 5 watts. A new conduction calorimeter with a range of 5 milliwatts to 15 watts was further developed. To calibrate still larger high-frequency

power sources a liquid-flow calorimeter type of power meter was designed.

Development work on the evaporated thin-film rf leads required for these

calorimeters was essentially completed. A new method of measuring

microwave power has been under study. This method, which shows

promise particularly for pulse power, is based on the interaction of an

electron beam with the rf field in a waveguide.

Since the design and construction several years ago of the first microcalorimeter for use in the primary standard of microwave power, it has

been found desirable to improve upon its design. The new model in- corporates such features as a special thermally isolated section of waveguide to replace the former air-gap, improved ambient temperature

control, bolometer mounts that can be tuned within frequency limits of

waveguide size, and a more rugged construction than the former model.

Work was also resumed on the high-power, stirred -water, adiabatic

calorimeter to improve its design and operating characteristics. A complete system of power measurement at ultra-high frequencies at comparatively low power levels was improved during the year. Refinements

included improved modulation techniques, adjustment of bolometer

resistance to prescribed values, and the modification of commercially

available slotted lines. Much of the present effort in improvement of

power-measuring techniques is being directed toward their use in the

Calibration Center.

Voltage Standards. Wide interest in the recent development of new

attenuator-thermocouple -type high-frequency voltmeters, having exceptional stability, has encouraged the design and construction of two new

103
An experiment conducted over an extended period has demonstrated that

communication by ionospheric scattering is feasible at a range of 1,400 miles

(p. 94). The test range was Newfoundland to the Azores. models. These cover the frequency range from 30 kilocycles to 100

megacycles per second. Patent proceedings were initiated on these

instruments. A helpful nomograph was devised to facilitate their use. The development of balanced voltage standards from 300 to 1,000

megacycles per second was begun. Resistors for micropotentiometers

used in balanced circuits and, to correlate results, a crystal-type balanced

voltmeter were designed and constructed.

Improved fabricating techniques for 1-milliohm resistive elements of high-frequency micropotentiometers were developed.

2.16. Basic Instrumentation

Six years ago, a program in basic instrumentation was instituted at the Bureau in order that it might better serve as a research, reference,

and consultation center on problems of instrumentation for the laboratories of Government and industry. Sponsored by the Office of Naval

Research, the Air Research and Development Command, the Atomic

Energy Commission, and the National Bureau of Standards, this program

represents an effort to utilize the Bureau's facilities and experience in the

field of physical measurements to advance those techniques of measure- ment and control that are fundamental to progress in science and industrial technology. To this end, it coordinates the specialized knowledge

and skills of Bureau staff members in a wide range of subjects that are 104
relevant to the solution of instrumentation problems—among others, in

electronics, engineering mechanics, chemistry, thermodynamics, optics,

sound, and atomic physics. In addition, however, the program endeavors to encourage and stimulate research and development throughout the Nation on measurement

devices and techniques. To fulfill its responsibility as technical consultant to Government and industry on instrumentation, it maintains

active familiarity with technical progress in other measurement laboratories and it cooperates with technical societies in promoting instrumentation progress. Moreover, it cooperates with other Government agencies

in arranging conferences and symposia on subjects of special interest or

of rapidly developing importance in the field of instrumentation. These

activities often help to define areas of instrumentation in which research

and development work needs to be done, either at NBS or elsewhere.

The principal emphasis, throughout the program, is on the basic fundamentals of measurement and control and on development of the science of instrumentation. Preference is shown to those research projects that seem likely to have broad utility in measurement or to extend significantly

the range, reliability, or sensitivity of some general class of instruments.

Also given primary consideration are theoretical and experimental studies of problems common to many instruments—such as drift, lag, unsteadiness—or of the limits of performance inherent in various types of

instruments.

One extensive group of problems relates to the handling of signals.

Because the output of any sensing element is a signal, such problems can

be profitably studied on a quite general basis, without regard to particular

types of measurement. Areas in which such general studies are en- couraged include amplification, loss of information in transmission,

analog-to -digital conversion, indication or display, recording, separation

of measurement signals from extraneous signals or noise, automatic data

correction or reduction, automatic computation, and automatic control. The research and development activities of the instrumentation pro- gram have two principal objectives: (1) systematic analysis of available

methods and devices in terms of their performance and characteristics,

and (2) research on new applications of principles and materials, leading

to the development of novel instruments and techniques. This part of

the program is carried out largely through the assignment of instrumentation research projects to those NBS laboratories that are best qualified to conduct research in the particular field of science involved. The basic

instrumentation facility also includes a small laboratory staff for investi- gation of special problems and a group of specialists in instrumentation

literature who are developing a reference and consultation service to aid

in the solution of instrumentation problems.

New Instruments. During the past year, projects in the basic instru- mentation program were conducted in eight of the technical divisions of the Bureau as well as in the basic instrumentation laboratory itself. 105
The accomplishments of the projects carried on in the technical divisions

include: the development of an instrument for measuring very small

alternating currents, such as are encountered in transistor circuitry,

without breaking into the circuit; an improved galvanometer design which

optimizes sensitivity and speed of response; successful development of

instrumentation for the measurement of voltage ratio of transformers

for computer application with extremely high precision; the development

and successful testing at ordinary temperatures of evaporated film strain gages which promise usefulness at high temperatures; development of an

instrument for measurement of dynamic bulk modulus; development and

construction of microwave components for 3 -millimeter microwaves in connection with development of a microwave interferometer.

The projects handled in the basic instrumentation laboratory itself are generally confined to those that call for exploratory studies by a

versatile group specializing in instrumentation. When such an activity

is seen to merit a full-scale project, it is turned over to the proper technical

division for further work. Selected projects conducted in the basic

instrumentation laboratory are discussed below. Instrument Reference Service. Both the newness of the field of in- strumentation and its rapid growth have posed problems for those scientists in Government and industry who need to have convenient, rapid,

and thorough access to instrument information. Two major obstacles stand in their way. The first is the inadequate coverage of instrumentation provided by existing abstracting and indexing services whose main

interest is the information obtained by use of the instrument. The

second is the lack of efficient classification systems for instrumentation.

The Bureau has therefore established an instrument reference center whose objective is to improve accessibility of instrument information in four ways: (1) by developing improved systems for storage and retrieval of information; (2) by fostering developments elsewhere that will make

instrument information more readily available; (3) by surveying specific

developments in instrumentation; and (4) by providing consultation

services in instrumentation.

Indexing System. The system for indexing the literature on instru- mentation, whose development was described in past reports, is now in

full-scale operation. More than 10,000 references were selected, classified, and coded during the past year. Improved card punches have been

designed and are now being constructed. These will increase efficiency of punching and hence reduce costs. Improved card materials were also developed.

As increasing numbers of instrumentation inquiries from other Government agencies and their contractors are being answered, a revision

of the previously prepared report, "Instrumentation Literature and its Use," was completed and issued as NBS Circular 567, with the title, "Guide to Instrumentation Literature." Demand for this circular has

been so great that a second printing has been ordered.

106
Transmitting antenna atop Pikes Peak (left) and the Colorado Springs (Colo.)

recording site terminal (right). These installations are used in phase stability experiments to determine the effects of atmospheric turbulence on UHF and microwave transmissions (p. 96). The transmitting and receiving antennas shown operate at 1,046 Mc.

Surveys. Another important service of the basic instrumentation pro- gram is the preparation of critical surveys of various areas of instru- mentation. These are conducted in order to provide systematic analyses

of available methods and. devices in terms of their performance and characteristics. Whereas such surveys are of general usefulness, they should

be particularly valuable to those charged with planning or conducting

research and development on the devices or in areas where they will be

needed. As with other portions of the basic instrumentation program, some of the surveys are conducted, by the staff members of the technical

divisions and others are conducted by basic instrumentation personnel. In the past year a survey of thickness measurements has been completed and is being prepared for issuance as a Bureau circular. The first part of a survey of recording methods and instruments has been completed and is undergoing editorial review. It will appear as volume I of the complete survey and will be titled "Recording Surfaces."

3. Calibration, Testing, and Standard Samples

The policy of the Bureau to foster and encourage the development of

standardizing laboratories by private enterprise was emphasized in a

talk by the Director at the dedication of the Eli Whitney Metrology

Laboratory, the first commercial laboratory to engage in the calibration

of gages for the public on a fee basis. At this dedication it was pointed out that at the end of World War I the Bureau had a staff of over 160

engaged in the calibration of gages whereas at the present time, with a 408368—57 8 107
vastly greater industrial economy, only eight persons are required to

calibrate the precision gages now utilized by others to carry out the bulk

of the calibration. Similar situations are in effect in a number of other

areas of calibration. Thus the Bureau is able to devote more of its resources to developing new standards and providing the higher degree

of accuracy required by modern industry.

3.1. Retention of Service Fees

Public Law 940 of the second session of the 84th Congress authorized

the Bureau to utilize its Working Capital Fund as a revolving fund for the conduct of services for the public as well as for other agencies. Hitherto fees paid for receipts from the calibration of standards and the sale of

standard samples to the public have been deposited in the Treasury and

the cost of doing the work has been defrayed from the Bureau's appropriation.

The new law authorizes the Bureau to finance the cost of services for private organizations by retaining the fees charged for those services. These charges are based on the estimated cost of the service and the fee schedules are published from time to time in the Federal Register.

The law makes no change in the services that the Bureau is authorized

to perform for the public. These services will continue to consist very

largely of the calibration of standards and the sale of standard samples

as published in Test Fee Schedules of the National Bureau of Standards

(Federal Register, March 30, 1956) and Standard Samples and Reference

Standards (Federal Register, July 3, 1954 and NBS Circular 552). The

Bureau undertakes tests of products only when it has special facilities that are not available elsewhere. The fall text of the law is given on

page 140 in the appendix.

3.2. New Calibration Facilities and Equipment

New calibration facilities are constantly under development at the

Bureau in order to meet the needs of science, industry, and the Government for greater accuracy and new and improved standards. These

range in size from small items of laboratory equipment to the Boulder

Laboratories' new Calibration Center which, when completed and fully

equipped, will represent an investment of nearly $2 million. Electronic Calibration Center. Plans have been completed and actual

construction begun on the Boulder Laboratories' new Electronic Calibration Center. Simultaneously, work has been under way on the design

and construction of over $1,000,000 worth of interlaboratory standards

and specialized equipment for the Center, so that operations can begin

as soon as construction is completed early in fiscal year 1958. The

Calibration Center will occupy a new, 27,000-square-foot wing of the

Radio Building, and will have greatly expanded facilities for calibration

services and research on high-frequency electrical measurements of all 108
kinds. The initial impetus to establish the Center came from the urgent

and continually increasing need for accurately calibrated electronic

equipment by the armed forces. Strong support for the new facility was provided by several branches of the military services, especially

the Air Force and the Navy Bureau of Aeronautics, and by various

industrial laboratories.

It is estimated that regional depots of the Air Force and Navy Bureau

of Aeronautics alone, that check the accuracy of electronic equipment

used in flight, will send in nearly 4,000 items annually for calibration. These items and those submitted by other sources will include many

types of interlaboratory standards that will be calibrated against the

master standards at the Center. The standards will, in turn, be used to assure the accuracy of working standards in laboratories and on the

production line. Initially, the Center will perform calibrations at frequencies already in wide use ranging up to 10,000 megacycles per

second. It aims eventually to measure and standardize all usable electrical and radio quantities from direct current, or zero frequency, to at

least 100,000 megacycles per second. The range from direct current up

to 30 kilocycles per second will be shared with NBS in Washington.

Anechoic Chamber. The Bureau's anechoic chamber (i. e., one free of echoes) has been reconstructed and will enable the Bureau to satisfy

the need for free -field calibration of microphones and sound level meters of special types used by the medical profession for the accurate measurement of noise at high levels. Freedom from interfering wall

reflections and echoes is attained in the chamber by lining its walls with

highly sound-absorbent acoustic wedges. It is expected that within the

range of frequencies from 80 to 20,000 cps the walls of the chamber will

reflect less than 1 percent of the sound energy incident upon them.

Large Capacity Balances. Two new precision balances of 1,000- and

2,500-lb capacities were constructed. They are equipped with special arrestments and built-in weight-handling devices to facilitate operation.

The larger balance will be installed at the Bureau's Master Railway

Track Scale Depot at Clearing, Illinois, and will be used to enhance the

precision of standards used for calibrating master and other railway track

scales. The smaller balance will be installed at the NBS Boulder Laboratories and will, for the first time, provide weight calibration service for the States in the western plains and the Rocky Mountain areas. Both

balances will be used for standardizing 500- and 1,000-lb test weights

used by State agencies engaged in scale-testing activities and by commercial concerns engaged in the manufacture of conventional, or the

development of new types of weighing scales and other force -measuring

devices. Improvement in Gage-Block Measurement. Two important improvements were introduced to speed calibration of gage blocks submitted by

industry and Government agencies. For calibrations of lesser accuracy, measurement on a mechanical comparator has been substituted for the

109
Radio noise recorder (left) used to measurejthe noise power available from

a standard antenna system. At right, antenna and equipment shelter for measuring atmospheric noise at Point Barrow, Alaska (p. 96). more laborious interferometric comparison formerly employed. The

comparator has two opposed sensing elements, one bearing on the upper

surface of the gage and the other on the lower surface. Thus errors arising

from imperfect seating of the gage on the anvil of the comparator are avoided. To give greater precision each gage is compared twice, the

comparisons being with two different standard gages. Gages requiring greater accuracy are calibrated by absolute interfero- metric measurements. To increase the efficiency of this method of cali- bration, a set of cards have been prepared, one for each nominal length

of gage. These cards bear tables that enable the true length of the gage

to be determined, after the fractional fringes have been found with almost no computation.

The introduction of these two improvements not only reduces the time

required to calibrate a set of gage blocks but also enables the work to be

done by personnel with less training. Formerly it took months of train- ing to insure competence in the making of absolute interferometric measurements whereas now a less skilled person can be taught in a few weeks.

3.3. Calibration Services

The volume of calibration of electrical standards and measuring instru- ments has continued at a very high level, constituting a fee value of about

$65,000. Over 2,000 electrical standards were tested, as well as over 500

instruments, whose calibration required about 11,000 determinations.

A number of instruments submitted for test were copies of such instru- ments developed by the Bureau for its calibration program. This is a

definite indication of the increased accuracy required by industry, a need

that has resulted in the establishment of standardizing laboratories by a number of large manufacturing companies, and by the military organiza110
tions. The Bureau must continuously improve its standards and measuring procedures to keep ahead of such demands for higher accuracy. The United States leads all other countries in the mass production of

machinery and mechanical components. A large proportion of these are to close fits and narrowly restricted tolerances. To maintain inter- changeability as well as assure proper functioning of such parts it is necessary that the production and inspection be based on highly accurate dimensional standards and master gages. During the year calibrations

and tests of such items for industry, and to some extent for Government

agencies, involved some 4,173 precision gage blocks, 270 master thread

gages, 59 plain gages, 1,700 thread measuring wires, 1,066 standardized

instrument parts, and 57 miscellaneous items.

During the year, 1,494 liquid-in-glass thermometers, 112 resistance

thermometers, 349 thermocouples and thermocouple materials, and 20

optical pyrometers and pyrometric lamps were calibrated for the public and state institutions. An additional 234 instruments, including

149 deep sea thermometers, were calibrated for other Government

laboratories. Formerly the Bureau individually calibrated large numbers of clinical thermometers for the Veterans' Administration for use in hospitals. Now,

by the use of a statistically designed sampling plan, it has been found

possible to ensure an adequate control of the accuracy of the thermometers

by examining only a fraction of the total. During the past year, for example, it was necessary to test a sample of only 13,235 thermometers

out of a total of 255,937 that were submitted.

Nearly 125 heavy water samples were analyzed for deuterium content

in cooperation with research groups under the sponsorship of the Atomic

Energy Commission. These samples were in the form of blood or water

that had a deuterium concentration less than normal water or commercially-available heavy water. Forty representative samples of aviation gasoline were submitted by the Air Force for determination of their heats of combustion and for investigation of possibilities for correlating the

results of such measurements with more easily measured properties of

these fuels. About 170 viscometers were calibrated and 848 standard

viscosity samples were distributed. Certification tests were made on

one batch of 7i-heptane and 2 batches of isooctane reference fuels. Tests were made for Government agencies of 4 samples of lubricants, 3 gasolines, and 17 fuel oils. Fifteen hundred radium sources totaling 10,980 milligrams and 263

cobalt-60 sources totaling 11,811 millicuries were calibrated during the

year. Calibrations of radiological instruments included: 104 r-meters and other Radiac instruments, 382 photographic and chemical dosimeters,

42 special purpose radiological instruments, 16 cobalt-60 instrumentcalibration ranges, and 3 tests of major items of X-ray equipment. Five neutron sources and six neutron survey meters were calibrated and eight

foils were activated in the standard thermal neutron flux. Reference

111
Improved precision equipment, left, has been developed for calibrating | waveguide-type attenuators at microwave frequencies (p. 99). At right is shown a primary standard of inductance that is also used to measure the

high-frequency characteristics of magnetic materials (p. 99). sources of radioactive cobalt-60 and strontium-90 were prepared for use j on the atomic powered submarines U. S. S. Nautilus and Sea Wolf.

3.4. New Standard Samples

The establishment of 27 new standard samples brings to a total of about

575 the materials of certified properties, purity, or composition that are now available to science and industry. The new samples include a high

pH standard, 3 samples of certified composition, 2 additional samples of

rubber compounding ingredients, 7 radioactivity samples, and 14 new

spectrographic standards.

The NBS standard pH scale is defined in terms of several fixed points

in somewhat the same manner as is the international temperature scale. The primary standards are solutions whose pH values are only slightly affected by dilution or by accidental contamination with traces of acid or

alkali from the walls of the container or from the atmosphere. The

substances from which the standards are prepared are stable materials

obtainable from the Bureau in the form of certified samples. In response

to the need for a highly alkaline standard to increase the accuracy of

high-pH measurements, a new standard consisting of a saturated solution of calcium hydroxide was developed. With this new standard and the five standards previously established, the NBS scale now covers the pTL range

1.68 to 12.45 from 0° to 60° C. The three new standard samples of certified composition include a white

iron, a portland cement, and a heat-resisting cobalt-base alloy. Nine

renewals of exhausted standards were also prepared and included 5 steels, 1 cast-iron, 1 aluminum-base alloy, 1 lead-base alloy, and 1 titanium

dioxide. With the two new rubber compounding samples, 13 standard samples of

rubber compounding ingredients are now available. Two of the existing

standards were exhausted during the year and replenished. The demand

for standard samples of paper for calibration of carbon arc fading lamps

increased 20 percent over 1955. A total of 3,695 samples for rubber

112
compounding and 473 samples of calibrated papers were issued for a total value of $11,968.50. In response to demands growing out of the increasing use of radioactive

isotopes in industry, medicine, and scientific research, the Bureau established seven new standard samples of radioactivity. Three new alpha - particle standards consisting of polonium-2 10 deposited on palladium on

silver disks were developed. These standards, of great mechanical

durability, have little or no alpha straggling and no beta component.

Also produced or released for distribution were four new beta- and gamma- ray solution standards consisting of hydrogen-3, potassium-42, zinc-65,

and tantalum-182. During the fiscal year, 900 standard samples of

various radioactive isotopes were distributed.

The 14 spectrographic standard samples announced during the year

include 6 stainless steels, 2 nickel oxides, and 6 zinc-base standards.

This expanded spectrographic samples program is designed to meet the

urgent need of industrial and Government laboratories for standards of

this type. Also in demand are such standards as titanium and hightemperature alloys which are currently under development.

3.5. Testing for Government Purchase

The Bureau tests products for Government purchase only at the

request of the agencies responsible for buying or using the specific

items. The service is concerned principally with products such as cement, dry cells, lamps, and mapping cameras which are purchased

under circumstances such that a single agency can effectively control

the procurement for the entire Government. In addition small numbers

of tests are conducted on a very wide variety of items to supplement the

testing services of other Government laboratories. The entire operation

in fiscal year 1956 amounted to $1.2 million which represented only about

9 percent of the total work done for other Federal agencies. Cement. The Bureau conducts acceptance tests on cement purchased

by the Federal Government for use in dams, locks, monumental public

buildings, airfields, and other structures that are designed for high

strength and very long life. Laboratories are maintained by the Bureau

for this purpose in Allentown, Pa., Denver, San Francisco, and Seattle

as well as in Washington, D. C. A mobile laboratory has been outfitted

for physical testing of cement and is available for use in those areas where a considerable amount of construction is in progress and time

schedules do not permit sending samples to the central laboratories. A new sampling and testing plan for cement has been placed in operation. This plan, based on a statistical study of the quality of cement

produced at the different mills, will furnish more information relative to the quality of the cement used with a reduced amount of testing. In

1956 about 30,000 samples were tested, representing approximately 15

million barrels of portland cement. In addition, tests were made on

4,900 hardened concrete specimens and on 550 aggregates. In localities 113
where the service was not available from other agencies, the engineering I properties of 350 soil samples were determined.

Lamps. The contract between the Government (Federal Supply ! Service) and the suppliers of electric lamps specifies that the lamps ! shall comply with the applicable specifications, and that the necessary

inspection and testing to determine compliance be performed by the

Bureau. The tests are applied to all types of lamps including incandescent, fluorescent, and photographic flash lamps. During fiscal year

1956 samples inspected represented over 4,000,000 lamps, of which

approximately 4.0 percent were rejected on initial inspection at the

factories of the suppliers. Lamps of current suppliers started on life

| test totaled 4,416 and those rejected represented approximately 3.2 percent of those accepted on initial inspection.

Mapping Cameras. The Bureau provides the only service available

to the Government for the accurate calibration of airplane mapping j cameras, measurement of the image -forming characteristics of optical

j systems, and accurate measurement of the refractive indices of optical i media. Because final map accuracy depends upon exact knowledge of

the performance of the lens as mounted in the camera, various Government mapping agencies require that cameras used by private contractors I on Government projects be calibrated by the Bureau. During the year

40 cameras were calibrated for important mapping projects.

Organic and Fibrous Materials. A total of 5,583 items of organic and

fibrous materials were tested for Government agencies in conjunction ! with their procurement or development programs. Typical materials

and products tested were weather balloons, denture base resin, hose,

electrical insulation, tires, plastic floor tile, linoleom adhesives, teletype

tape, thermal insulating materials, and conveyor belting.

Building Materials. Much of the Bureau's testing of building materials

| is conducted for the purpose of obtaining design data and determining

how a particular product can be used advantageously. During the year, however, 111 items ranging from masonry and roofing to fire extinguishers j were tested for compliance with applicable Federal specifications. Thirty- six of these items, or about one-third, failed to meet the specification

requirements, indicating the importance of testing in this area. 3.6. Assistance to Other Laboratories

I The Bureau renders assistance to both Government and private laboratories in advising them as to methods and equipment. During the year

a number of organizations, both public and private, that were planning

to establish calibration laboratories sent their technical directors and j supervisory scientists to the Bureau to discuss general problems of layout

and facilities and to obtain information about the design and installation

j of equipment. Similar service was rendered in connection with testing

laboratories. A special activity in this area is the joint operation by

public and private agencies of the Cement Reference Laboratory.

114
j I

A tunable frequency stabilizer, left, designed to operate over the useful range of any one waveguide size (p. 100). This equipment provides a signal source with a frequency stability of better than 1 part in 100,000 over a period

of 1 hour. Right: A wide-temperature-range cavity for automatically

measuring the high-frequency dielectric properties of insulating or semiconducting materials (p. 99). Cement Reference Laboratory. In 1956, seventy -seven cement laboratories availed themselves of the cement testing program of the Cement

Reference Laboratory. This laboratory, located at the National Bureau

of Standards, is jointly supported by the Bureau of Public Roads, the

Army Corps of Engineers, the American Society for Testing Materials,

and the Bureau. The major part of the CRL work is accomplished

through inspection visits to the numerous cement testing laboratories

throughout the country. Upon request, cement laboratories are visited in the course of regularly arranged schedules that cover the field in a period of 2 to 3 years. An inspection includes observance of methods,

inspection of the cement testing apparatus, verification of compression

testing machines, and observance of facilities for curing test specimens.

When needed, the inspector demonstrates the standard test methods.

At the conclusion of an inspection, the inspector's data sheets are re- viewed with an appropriate member of the inspected laboratory's staff, and recommendations are made. Subsequently, a detailed written report

is issued to the proper supervising official. No certifications or ratings

of laboratories are given, and the findings and the reports are confidential. At intervals, the Reference Laboratory distributes a comparative test sample of portland cement to over 200 laboratories. A test sample

enables a laboratory to ascertain how its test results compare with many

other laboratories. The CRL has also maintained, for distribution on

request, samples of its specially prepared material for calibrating the

flow table apparatus for determining the percentage of water to be mixed

with standard test mortars. 115
3.7. Special Tests

A wide variety of special tests were conducted for other Federal

agencies. The following are typical examples. Air samples taken on

the U. S. S. Nautilus during its 10-day submerged trial cruise were

analyzed in the radon testing laboratory. Among the 616 chemical and

isotope analyses for other Government agencies were analyses of hydrogen

from blood samples to determine the deuterium content. These analyses

are made for the Surgeon General's Office in connection with medical

research on the assimilation of heavy water by people in normal health

and by those in a condition of shock.

During the year the Bureau undertook a program of assisting the Veterans' Administration with preparation of specifications and making physical tests of hearing aids purchased for veterans with a service incurred hearing loss. Test equipment was assembled, and 142 hearing

aids were tested for such factors as response-frequency characteristics

and distortion. Also, it is planned to develop tests for hum pickup and

temperature effects which will be incorporated in future specifications

and tests. At the request of the Federal Housing Administration, performance

tests were conducted of heating and air-conditioning systems in a house

of novel design. The house was first equipped with a special electric heating system (heating coils in coves around the walls) and reflective wallpaper and drapes. It was then altered to include a gas heating

(ethylene -glycol) system; the roof was also insulated with reflective material. At the same time, a cooling system was installed with copper

tubes in the coves serving both to warm the house in winter and cool it in summer. Heat transmission data useful for design purposes were thus

obtained.

The Bureau conducted extensive evaluation tests of night air-sea rescue operations using powerful aircraft-mounted searchlights in conjunction

with retroreflective materials attached to the clothing and gear of downed

pilots. The results indicated that such equipment greatly improves the

chances of rescue.

4. Cooperative Activities

The diversity of the Bureau's program, facilities, and staff in the

physical sciences gives rise to its broad cooperative and consulting activities for Government, science, and industry. These activities range from

the development of codes and specifications in cooperation with other

groups to active participation in technical society programs and to advisory service for other Government agencies in all areas of the physical

sciences. Working largely as a collaborator in the area of codes and specifications,

the Bureau seldom initiates work or promulgates a finished document.

Nevertheless, it often makes a major contribution by providing methods

116
of test, basic scientific and technical information on properties of materials and related subjects, and standards of measurement without which

no other standards are possible. Bureau staff members actively participate in national and international professional societies. This work

greatly enhances the dissemination and utilization of NBS research,

development, standardizing, and testing activities. Also, staff members

are able to keep in close touch with technical and scientific advances else- where and to coordinate the standards and specifications used in industry

with those employed by Government.

The Bureau's participation in many of the cooperative activities was

implemented by membership of staff members on committees of national

societies and other organizations concerned with standardization and

related activities. In 1956 about 110 of these scientific and technical

organizations were served by 1,300 committeeships held by Bureau personnel. About 30 percent of the committeeships were in the American

Society for Testing Materials and 20 percent in the technical committees

of the American Standards Association. The Bureau was represented on 20 boards and committees of the Federal Government by 84 committeeships, and on 22 committees of international organizations by 83

committeeships. Two hundred and eighty -five of the Bureau representatives held offices of their committees.

4.1. Federal Specifications

The Federal Government is the largest single purchaser of a large

variety of materials and products. In order to provide standards and

uniform procurement specifications for these materials, the General Services Administration has sought the assistance of NBS and other agencies

by asking them to accept the responsibility for the preparation of procure- ment specifications and test method standards in areas in which they have

competence. The Bureau has accepted responsibility for the preparation

and maintenance of 180 Federal Specifications covering a wide range of

materials and products. In the preparation of specifications, knowledge

gained for research and development work undertaken for another pur- pose and from the testing of materials purchased by Government agencies

is often utilized. Information concerning new developments and manufacturing practices obtained from cooperation with technical societies is also used in keeping specifications up to date. In fact, this familiarity

with the work of the technical societies makes it possible for industry

specifications to be readily evaluated and often adopted as Federal Specifications. In addition to preparing assigned specifications, the General Services

Administration requested the Bureau to review approximately 500 pro- posed specifications prepared by other agencies to determine their acceptability as procurement documents. Most of the changes suggested

concerned the procedure for evaluating the material or product.

117
Newly built anechoic chamber for testing and calibrating acoustic instru- ments. Glass fiber wedges that line walls, ceiling, and floor absorb about

99 percent of incident sound energy (p. 109). 4.2. Methods of Test

The development of test methods is one of the statutory functions of

the Bureau. In connection with Federal Specifications, every effort is made to develop general methods that will be applicable to groups or

classes of products or materials rather than to individual items and to

utilize those that are standard with industry and technical groups to the

greatest extent practicable.

The Bureau has accepted the responsibility for the development and

maintenance of test methods for adhesives, plastics, rubber, paper, leather,

textiles, nontextile resilient floor coverings, paints, cement, detergents,

wire and cable, and laboratory glassware. These methods, issued by

General Services Administration as Federal Standards, include approximately 1,200 individual test methods and analyses as well as sampling

plans and definitions that are in common use in industry. In specifications for specific products and materials, it is only necessary to make

appropriate reference to these standards to assure suitable and uniform

tests for the evaluation of the product or material. Continuous revision of old methods and development of new ones are necessary to keep the

standards in step with rapidly changing technology.

4.3. Industry Specifications

In order that purchase specifications, standards, and methods of test have a real meaning and fulfill the purpose for which intended, Federal

and other specifications must be coordinated and brought into agreement

with those used by other groups and the industry concerned. The

Bureau has continued its active participation in the activities of technical

118
societies, industrial organizations, and standardizing groups preparing

such specifications. During the past year NBS members held about 400

committeeships in the American Society for Testing Materials and

approximately 260 in the American Standards Association. In cooperation with ASTM Committee D—11, a procedure was developed for interlaboratory studies of methods of test for rubber. The

Bureau contributed to the revision of the book "Reagent Chemicals,

American Chemical Society Specifications," by cooperating with the

Society in devising suitable standard test procedures for determining the

quality of reagents. Assistance was given the Society of the Plastics

Industry in the preparation of a standard for polyvinyl chloride plastic

sheet that is widely used in the construction of corrosion-resistant ducts,

ventilating equipment, and chemical plants. Because NBS Circular 31,

"Copper Wire Sizes," serves the copper wire industry as the standard

for the determination of wire sizes and other properties, the Committee

on Wires for Electrical Conductors of ASTM requested that the circular

be revised and brought up to date. The 4th edition of the circular was

published in January 1956. Working with the Illuminating Engineering Society, the Bureau played

a major role in the development of a dirtometer which measures the rate

at which dirt accumulates in space where lighting equipment is used.

Important assistance was given to a committee of the Society of Automotive Engineers in the solution of production problems for plastic lighting

panels and in the preparation of an industry guide for their manufacture.

The Formed Steel Tube Institute was assisted in the preparation of a

specification to be used by the industry in measuring the surface roughness of seamless steel tubing. At its annual meeting the American

Petroleum Institute favorably considered the Bureau's proposal to change

the class of thread on sucker rod joints to that specified in NBS Handbook

H28.

Standard type fluorescent lamps, widely used in the factory and office for economical reasons, are less favored for restaurant and home lighting.

The rendition of food and complexion colors by such lamps is unnatural

to the degree that the food sometimes appears unappetizing and people

unhealthy. However, improved color rendition is now possible with

deluxe type fluorescent lamps which have been developed to supply a greater proportion of long-wave (red) energy. The Bureau has cooperated

with the Illuminating Engineering Society in developing an index of

color rendition for appraising these lamps.

Also during the past year, a revised and enlarged edition of the compilation of "Phase Diagrams for Ceramists" was completed and published

by the American Ceramic Society. The edition contains 801 phase

diagrams, the work of 331 scientists, a glossary of 50 terms peculiar to phase studies, and a discussion of the interpretation of phase diagrams.

The compilation is a standard reference source used in ceramic schools

and research institutions throughout the world.

119
4.4. Cooperative Research With Industry

Many developments of scientific and technological significance have

resulted from the Bureau's Research Associate Plan, a cooperative pro- gram with American industry. This plan is an arrangement whereby

technical, industrial, and commercial organizations can support work at NBS on projects that are of special interest to them, yet of sufficient general interest to justify use of Government facilities. Research associate projects must not only be of value to all groups concerned in the

particular field and to the Federal Government, but must also be important from the standpoint of the Nation's sum total of technologic

knowledge.

Since the Research Associate Plan was established in 1920, about 180

organizations and individuals have supported cooperative research at the Bureau. At present 12 groups are supporting some 36 research

associates at NBS. Research associate projects active during the past

year are as follows:

Sponsor Field of Activity

Aluminum Company of America Reflective insulation American Dental Association Dental research and testing

American Electroplaters Society Electroplating

American Iron and Steel Institute Properties of reinforced concrete American Society for Testing Materials Cement reference laboratories Asphalt Roofing Industry Bureau Asphalt roofing research Bone Char Research, Inc Research on adsorbents for sugar

refining

Calcium Chloride Association Hydration of portland cement

National Research Council Masonry research and fire resistance Porcelain Enamel Institute Test methods for porcelain enamels

Portland Cement Association Cement research

Joint Committee of Chemical Analysis by X-ray Standard X-ray diffraction powder

Diffraction Methods (ASTM & Am. Crystal- patterns

lograpbic Assoc.). The results of the projects supported by the Research Associate Plan

become a part of the public domain and are published by the Bureau.

Whereas many projects are specific in nature and of short duration,

others, such as those sponsored by the Portland Cement Association

and the American Dental Association, are directed toward fundamental

research and have been active for a number of years. During 1956

accomplishments of the program, reported in section 2, included a comparator for measuring dimensional accuracy of dentures (p. 57), phase

equilibria studies of cement (p. 65), standard X-ray diffraction patterns

of many new materials (p. 67), and the performance of panel insulated

with reflective membranes (p. 73).

Closely paralleling the Research Associate Plan is another important

area of cooperation between the Bureau and industry. This program was authorized in 1950 by Public Law 619 (81st Cong.) in which

. . The. Secretary of Commerce is authorized to accept and utilize 120
A total of 27 new standard samples were established during the year to meet

the ever increasing needs of science and industry (p. 112). The tool-steel standards, inset, are among the 14 recently announced spectrographic standards. The homogeneity of the new samples is measured in the sensitive photoelectric spectrometer shown.

gifts or bequests of real or personal property for the purpose of aiding

and facilitating the work authorized herein . . . ." The arrangement

thus 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 some 17 projects were supported by gifts from 14

organizations. They were as follows: Donor Field of Activity

Aluminum Company of America Reflective thermal insulation American Instrument Company Vapor liquid phase relations American Iron and Steel Institute Spectrochemical standard samples,

ship steel research, and design

stresses in reinforced concrete American Society for Testing Materials Testing light and color Corrosion Research Council Fundamental reaction of surface

crystals Georgetown University Physiological research, and variable heartpump

International Nickel Company Effect of nickel on thermal conductivity of ferritic steel National Electrical Manufacturers Association _ _ Refrigerator safety

121
Edward Orton, Jr., Ceramic Foundation Mechanism of plasticity in clays Radio-Electronic-Television Manufacturers Asso- Standards of color television

ciation. Sugar Research Foundation Invert sugar solutions Welding Research Council Stress corrosion of stainless steel Anonymous Phenomenon of crystallization

Anonymous Ether peroxides

4.5. Weights and Measures

The translation of the national standards of length and mass and of

the derived standards of capacity to the channels of industry and trade

are matters of great economic importance to the producing, manufacturing, processing, and distributing agencies of the Nation, and to all purchasers of commodities and services. The Congress has left to the in- dividual States the responsibilities of regulating commercial weighing

and measuring devices and controlling commercial transactions involving

quantity. The Bureau cooperates with the States in promoting uniform,

effective, and efficient weights and measures supervision through uniform

laws, standards, methods of inspection, and administrative procedures.

Thus, the national standards of measurement are translated into everyday

use. The coordination of this cooperative program rests in the Bureau's

Office of Weights and Measures. Commerce, business, and consumers

are becoming increasingly aware of the importance of adequate weights

and measures administration and, through such administration, accurate weighing and measuring. As a result, greater demands are made upon

the Bureau each year for assistance and advice in this field. The NBS Office of Weights and Measures plans and conducts several integrated programs of assistance to States and local jurisdictions and to business and industry. The range of consultative services is broad, embracing the drafting of new legislation; the development of regulations,

including technical specifications and tolerances for devices; guidance in administrative procedures; design of testing equipment; and preparation

and distribution of recommended testing methods. Also included under

the administration of the Office is the physical adjustment of State refer- ence weights and measures standards.

During 1956 the Bureau stepped up its on-the-job training program for technical personnel from State governments. Upon request the Bureau

studied weights and measures activities in the State of Pennsylvania and

the Commonwealth of Puerto Rico and made recommendations on amendments of statutes, personnel and equipment requirements, and

general administrative procedures. Implementation of the Bureau rec- ommendations is now underway and is expected to result in improved

services to these communities at lower costs. One of the principal tools of the Bureau in its effort toward nationwide

uniformity in weights and measures administration is the National Conference on Weights and Measures sponsored by NBS since its inception in

122
I 1905. The 41st Conference, held in Washington in May, was attended

by almost 500 delegates, representing 40 States, the District of Columbia,

j Puerto Rico, the Philippine Islands, and all phases of business and industry

I associated directly with weights and measures supervision. The Conference concerns itself with the technology of weights and measures

j supervision and adopts and recommends to the States model laws and

regulations. Among the more significant actions by the 41st Conference

; was the adoption of a tentative code for liquefied-petroleum gas liquidmeasuring devices. This action represents the first effort to develop a

set of specifications, tolerances, and regulations for these commercial

measuring devices which are playing an increasingly important role in the Nation's economy.

The Conference heard a report from the Bureau in which model report

forms and reporting systems were recommended to State and local weights

and measures officials. The system is devised not only to make possible

uniform and orderly reporting of individual activities, but also to lead an

inspector into proper testing procedures. Among other topics covered

during the 5 -day meeting were prepackaged commodities (a commercial

marketing technique of growing significance); quantity control in packages; labeling requirements under the Federal Food, Drug, and Cosmetic

Act; and meat packinghouse products. A completely new automatic

prepackaging scale was also demonstrated to the delegates.

Previewed during the Conference was the second weights and measures

film, "Testing Mass Standards by Substitution," produced by the Bureau

as a training film for weights and measures officials. This 22 -minute,

16-mm, color and sound film portrays the importance of precision in the

testing of reference and field standards. Methods of test are explained

and demonstrated. These include the computation of the actual value

of a laboratory standard and the determinations of the acceptability of

a field standard within limits of allowable error. In addition to its application to weights and measures administration, this training film will be

useful to educational institutions, laboratories, and industries interested

in precise weighing. Prints of the film are available on loan, without

charge, or they may be purchased at nominal cost. With the rapid engineering advances in the instruments of weighing

and measuring, the enforcement official is finding that technological

approaches must be found for the solutions to the many problems en- countered. It is in this area that NBS is uniquely qualified to be of as- sistance in the field of weights and measures administration. Close contact with State and local weights and measures officials is maintained

and intimate understanding of their problems is gained through NBS

staff participation in regional and State conferences. Bureau personnel

also regularly visit the administrative offices and laboratories of weights

and measures jurisdictions and State and local people spend time in the

laboratories of the Bureau.

408368—57 9 123
4.6. Radiation Protection and Measurements

With the rapidly expanding uses of radiations and applications of atomic

energy, the work of the National Committee on Radiation Protection has

assumed greater importance and is receiving more widespread attention.

The Committee is sponsored by NBS and governed by representatives of

15 participating organizations; its membership is composed of over 100

leading scientists in the fields of radiation and related interests. Studies

are made of the problems involved in the use of radiations, and the result- ant recommendations are published as NBS Handbooks. During the

year, two such recommendations were issued : (1) Handbook 60 (revision of H41) which brings up to date the protection requirements for radiation

workers and the public in medical and industrial X-ray installations; and (2) Handbook 61 which presents the results of an intensive study of the problems involved in the legislative regulation of radiations. The

latter recommendation answers a growing need for guidance in the development of radiation control by Federal, State, and municipal agencies and

can be influential in the establishment of uniform control throughout the

country. Some of the new studies recently undertaken by the Committee

are the incineration of radioactive wastes, protection in the industrial and

medical applications of intense high-energy electrons, and permissible

irradiation levels for emergency conditions.

For many years, the NCRP has been looked to for primary guidance in

this country in matters of radiation protection, and many of its recom- mendations have been adopted internationally. Because of its recognized

leadership, the radiological groups in this country recently recommended

an extension in the scope of the Committee's activities to include problems

of radiation units and measurements for clinical and biological applications. This major broadening of interests has been accomplished with

the establishment of four new subcommittees to recommend standards

for measurement of radioactivity and radiological irradiations. The

subcommittee structure established by the Committee was recommended

for adoption by the International Commission on Radiological Units

during its April 1956 meetings in Geneva, and as a result the international

group has reorganized its Committee structure along similar lines. Important decisions relating to the measurement and safe use of radiations were reached at the triennial meetings of the International

Commission on Radiological Units and the International Commission

on Radiological Protection, both of which were held April 2-11, 1956, in Geneva, Switzerland. In a move to achieve greater international uniformity of X-ray measurements, the ICRU initiated a project in which

basic equipment, to be developed by the National Bureau of Standards,

will be loaned to countries that lack primary standards of their own. Another highlight of the ICRU meetings was a discussion of problems

raised in translating exposure dose measurements made in roentgens to the unit of absorbed dose, the rad. The principal outcome of the ICRP

deliberations was a revised set of recommendations for permissible levels 124
International comparison of X-ray standards. Swedish free-air ionization

chamber (left) and Bureau's primary standard (right) mounted on rails so they may be placed in turn before the same X-ray source (pp. 34 and 124).

of ionizing radiation to which humans may be exposed. The Bureau

continues to take an active part in the work of the two commissions, in which five NBS scientists now hold membership. One of these was

recently renominated for an additional 3 -year term as chairman of

ICRU.

4.7. Educational Program

Education and training at the Bureau are directed toward improvement

of the skills and knowledge of the staff. Designed to increase the efficiency of the staff's assigned duties and to prepare them for increased responsibility, this program includes lectures, courses, seminars, and colloquia.

These fall into one of the following categories depending on the subject matter; NBS out-of-hours, NBS in-hours, or NBS-university sponsored

out-of-hours. The flexibility of the program serves the varied and often changing

needs of the research staff. Highly trained scientists may present broad

surveys of areas of research, detailed treatment of a new or specialized area of research, or the practical application of a needed work technique.

Research workers from other Government agencies may enroll in NBS

classes if the knowledge gained will assist them in their official duties. Since the establishment of the educational program in 1908 over 12,000

registrations have been recorded; 170 graduate degrees have been awarded

by 35 different universities partly on the basis of credits obtained or thesis 408368—57 10 125
work carried on under the Bureau program. During the past year there were 1,293 registrations in 48 courses offered at the Washington and

Boulder Laboratories. In addition weekly staff talks and demonstrations

by specialists in various technical fields were given from September

through June, and five seminar groups met regularly on a weekly or biweekly basis. Approximately 140 college students were enrolled in the summer Junior

Scientist -Engineer program which is designed to prepare especially well- qualified students for future professional careers at the Bureau. The

students participated in a program of orientation, on-the-job training

assignments, and discussions with advisers from the technical divisions. During the past year the National Research Council-National Academy

of Sciences Postdoctoral Research Associateships were continued and five associates were appointed in the following fields: Atomic and molecular

physics, heat, general physics, sound, and mathematics.

4.8. International Cooperation

Through active participation in the work of international standardizing

bodies and professional societies, the Bureau is contributing to the estab- lishment of internationally recognized standards and practices of importance to American industry, technology, and science. Such standards

facilitate international trade and the exchange of data on the properties

and physical constants of materials.

During the past year, for example, a member of the NBS staff presided

at the meeting (in Paris, France) of the Technical Committee on Plastics of the International Organization for Standardization. The leaders of

the United States delegations to meetings of the Technical Committee

on Rubber (at Dusseldorf, Germany) and on Textiles (Southport,

England) of the same organization were from NBS. These meetings

and earlier meetings have resulted in no less than 63 standards relating to test methods and nomenclature for plastics (19), rubber (10), and

textiles (34). Many of these standards are well advanced internationally.

Three of the textile standards are cotton fiber testing methods whose

international recognition is urgently desired by the cotton industry of the

United States. An outstanding accomplishment at the meeting on

textiles, which was attended by delegations from 20 nations and three

international textile associations, was a unanimous decision to adopt

one system for expressing the "size," or weight-length relation, of all yarns and threads. This universal system is based upon the weight in grams of 1,000 meters of the yarn, called the ff Tex." The need for one system has been recognized for many years and the way is now clear for the system to be introduced into the technical literature and into industrial

use.NBS personnel participated actively in the preparation and review of documents for consideration by the International Radio Consultative

126
Committee (CCIR) of the International Telecommunications Union at

its next Plenary Assembly. In this connection considerable assistance was given the Telecommunications Policy Staff of the State Department.

Staff members contributed to groups studying the following subjects,

among others: Standard frequency transmissions and time signals; auto- matic monitoring of occupancy of the rf spectrum; accuracy of field- strength measurements by monitoring stations; and problems of manmade

interference. Other international meetings in which about 75 NBS members took

part are: International Antarctica Conference under the auspices of the

Special Committee for the International Geophysical Year (France);

Conference on Low Temperature Physics under the International Union

of Pure and Applied Physics (France) ; International Union of Pure and

Applied Chemistry (Zurich); Congress of Algebraic Topology (Mexico);

International Organization for Standardization (England); International

Commission on Radiological Protection (see 4.6 above); Western Hemisphere International Geophysical Year Conferences (Brazil) ; International

Commission on Illumination; Observation of Solar Eclipse in the AngloEgyptian Sudan; International Conference on the Peaceful Uses of

Atomic Energy (Geneva); International Union of Leather Chemists'

Societies (Stockholm); Conference on Nuclear Reactions (Amsterdam);

Ninth General Assembly of the International Astronomical Union

(Dublin); and Meetings of the Directors of the Building Research

Organizations of the British Commonwealth.

The Bureau has, since its establishment in 1901, welcomed the cooperation of foreign scientists and students in its research and standardization

programs. Under the various international fellowships and Point 4

programs, foreign nationals have worked with Bureau scientists on problems in the physical sciences of mutual interest to their countries as well

as to the United States. During 1956 the Bureau received more than

1,000 foreign trainees and visitors, many of whom spent time in NBS

laboratories as guest workers. Total inquiries for assistance by foreign

correspondence are estimated at 7,000.

Recently the Bureau was requested by the International Cooperation

Administration (Point 4 activity) to assist in training foreign nationals

who will assume important responsibilities in newly created standardization laboratories in their respective countries. Effective standardization

will, for example, enable these countries to better judge the quality of

their imports. At the same time they will be able to classify their exports (rubber, waxes, fabrics, ores, etc.) into quality groups arid hence

realize greater returns than is possible otherwise.

The nature and scope of this special program are indicated by the

following examples:

# Two foreign officials were trained, by staff members of the NBS paint and steel laboratories, in the use and performance of protective coatings as means of preventing

corrosion. 127
# A machine shop foreman from an underdeveloped nation spent several months

at the Bureau during which time he made unusual progress not only in mechanical skill but in leadership as well. For example, he achieved the skill of making precision measurements necessary to grind and lap a four-inch plate of steel flat to 1/100,000 inch and to lap and hone an internal cylindrical bearing to rigid specifications. $ Working in the NBS electrodeposition laboratory, a foreign specialist conducted

research on the composition of cathode films, a subject of practical significance in elec- troplating technology. He will continue his research when he returns to the staff of

his national university. Another trainee (from another nation) gained skill in the recently NBS developed process of "electroless" plating, which greatly facilitates nickel plating of intricate shapes and interior surfaces of tubular forms. £ A number of foreign leaders were assisted in their efforts to develop better housing

and more effective usage of building materials. A guest scientist from the Electro -Technical Laboratory in Tokyo will spend

l}i years at the Bureau working on impedance, attenuation, voltage, and other quantities at radiofrequencies.

4.9. Other Cooperative Activities

Safety Codes and Building Research. In the field of building, plumbing,

and safety codes, cooperative work with representatives of organizations

sponsoring model codes has continued to be effective. During 1956

assistance was given to the following municipalities in the preparation or

revision of their building or plumbing codes: Clifton Forge, Va.; Barre,

Vt.; Princeton, W. Va.; Plymouth, Wis.; Phillipsburg, Pa.; Buoy, Tex.; Port Allen, La.; Imlay City, Mich.; Forty Fort, Pa.; Kane, Pa.; District of Columbia; Columbiana, Ohio; Girard, Ohio; Northfield, Minn.; Newton, N. J.; San Diego, Calif.; Freeport, 111.; Savannah, Ga.; and Dayton,

Ohio.

The Bureau, either as sponsor or cosponsor, assisted in the preparation

or revision of a number of model codes including: The American Standard Building Code Requirements for Minimum Design Loads for Buildings; the National Electrical Safety Code; the Code for Protection Against

Lightning; and the Code for the Protection of Eyes, Heads, and Respiratory Organs of Industrial Workers. The Code on Minimum Design

Loads for Buildings was published by the American Standards Association

during the year. The Bureau assists a variety of Government agencies, including State,

county, and city agencies, in the solution of their problems relating to building construction, equipment, and materials. For example assistance was given to the Brookhaven National Laboratories in selecting materials

and in the design of the concrete base for an alternating gradient synchrotron. The base design called for several special features; it had to be free of differential movements and constructed of materials with an

unusual degree of dimensional stability. An essential feature is the

avoidance of differential movements of the base and an unusual degree

of dimensional stability of the materials. At the request of the Office of Chief of Engineers, the Bureau participated in investigations to deter- mine the cause of structural failures of the reinforced concrete girders in 128
A guest worker from Japan is instructed in a method for measuring magnetic

properties of powdered iron specimens by the use of a Maxwell bridge. This

is part of his training in high frequency methods at the NBS Boulder Laboratories (p. 126).

a number of widely separated buildings. As part of a larger program on the testing of protected metals (against weathering and fire) an NBS

representative visited three Air Force Bases in Alaska to evaluate pro- tected metals in Arctic climates.

Other advisory services included a survey of the Wind Cave Elevator

for the National Paik Service; safety recommendations for the monorail

car which carries passengers through the tunnel connecting the Senate

Office Building with the Capitol; discussions with the Capitol architect on the possibility of using moving platforms or moving sidewalks between

the Senate Office Building and the Capitol; assistance in preparing a

justification for a new elevator in the Washington Monument; and

discussions with the National Park Service on the possibility of a freight

elevator to serve the lunchroom in Mammoth Cave, Kentucky. The

Bureau assisted the Census Bureau in devising a method for cooling their electronic computer system, and prepared a report for the Navy on the

hazards of handling liquid oxygen. Conferences were also held with the

Department of Agriculture on refrigerated trucks and trailers, the General

Services Administration and the Commodity Standards Division of the

Department of Commerce on heating and air-conditioning equipment,

and the Office of Chief of Engineers on problems of water condensation

in building construction.

129
As an active participant in the Federal Construction Council, the Bureau

gave assistance to task groups assigned to study problems of plumbing,

windows, space allowance for office buildings, ceiling heights in office buildings, roof decks, built-up roofing, cooling towers, evaporative condensers, and other problems. Assistance was also given to the National

Research Council in the formation of a committee on fire research and in studies of a number of technical problems relating to building design, construction, maintenance, and operation.

Heat and Temperature Measurements. In an effort to correlate the

measurements in different laboratories and improve calorimetric techniques, the Calorimetry Conference was established a few years ago. In

adapting a plan to distribute to participating laboratories highly purified

substances for intercomparison of heat -capacity measurements, the Conference asked the Bureau to prepare and package the materials because

of its unique facilities and experience in working with substances of high

purity. Distribution of the materials to both national and foreign

laboratories has now been accomplished. Also, heat-capacity measure- ments have been made on these substances at the Bureau, and the results have been published in scientific journals for use in the intercomparison of

results or in the calibration of apparatus by other laboratories. Because of the inaccuracies that exist in the various "accepted" helium

vapor pressure scales of temperature, the Bureau undertook the precise

calibration of a magnetic thermometer against the different scales. The

results, presented at the Paris Low-Temperature Conference in September,

assisted the Conference in its interim proposal for a revised low-temperature scale for future work. Though NBS measurements favored one of

the two most widely "accepted" scales, the precision of vapor-pressure measurements at present is not high enough to remove all doubt about

the correct choice. Standards for Fuel Gas. In recent years the fuel-gas industry, acting

through the American Gas Association, has emphasized the need for a standard for the calibration of recording calorimeters used to measure

the heating-value of natural gas and similar fuel gases. Because such

gases are bought and sold on the basis of their heating value, accurate measurement of this property is important for economic as well as for technological reasons. During the year an arrangement has been completed whereby the American Gas Association will procure cylinders

filled with a purified natural gas (essentially methane), deliver them to the

Bureau for certification of the heating value of the gas, and then distrib- ute the cylinders to users—largely fuel -gas distributors and public utility

laboratories—for use as standards. In this way the Bureau will be able to render a significant service with a minimum expenditure of time and

effort in the mechanics of procurement and distribution. Certification

will begin early in fiscal year 1957.

130
Dental Materials. The dental research program at the Bureau is carried out in cooperation with the American Dental Association and

the Dental Corps of the Armed Services and the Veterans' Administration. A large part of the work is undertaken to provide advisory service to these agencies in the purchase and use of dental materials and equipment. During the year assistance was given to the Armed Forces Medical

Procurement Agency in the development of a method for testing the

eccentricity of dental rotating diamond instruments and to the National

Naval Medical Research Institute in evaluating an air turbine dental

handpiece and determining the dimensional accuracy of dentures.

Fluorescence methods developed at NBS were employed in cooperation

with the National Naval Medical Institute in a comparison of natural

and artificial caries (decay) of teeth. X-ray diffraction studies of lysine

-

deficient rat bone were made to supplement a study of bone growth by

the National Institute of Dental Research. Assistance was given to the

dental corps of the Armed Services in training dental officers in research

methods and use of dental materials. This was done through training

officers stationed at NBS, through lectures to groups who visited the

Bureau, and through lectures given as a part of the curriculum of the

Army and Navy dental schools. Lectures and demonstrations were also given at other dental schools and many meetings of professional dental

groups. Applied Mathematics. The Bureau maintains one of the principal

facilities to which other Federal agencies turn for assistance in the solution

of mathematical problems. One important aspect of the Bureau's work

lies in the fact that coding for electronic computation is done not only

for the Bureau's own machine, SEAC, but also for NORC, UNIVAC, and

IBM 704 at the request of other agencies. Among the many problems

studied during the past year were the solution of equations arising in a reactor design problem, application of the Monte Carlo method to radiation diffusion, award of contracts by linear programing, flood control problems, cost accounting operations, and the stability of sup- ported plates.

A form of sequential test procedure was worked out for use in experiments on ship steel plates for the Bureau of Ships—NRC Ship Steel Committee. A testing order was prescribed so that after only a little more than a third of the experiment was run the results could be analyzed

and, if necessary, the over-all plan modified to concentrate attention on

the most troublesome factors. This is but one of the Bureau's ever growing list of modifications of standard statistical experiment-design

procedures.

The Bureau also rendered major services to the U. S. Geological

Survey, the Diamond Ordnance Fuze Laboratories, and the Naval

Ordnance Laboratory on statistical aspects of the design and analysis

of experiments and tests. For example, an experiment was planned for

131
Extensive studies were made of retrort fie dive mate rials as a means of locating

downed pilots in night-sea rescue operations (p. 116). Retroreflectors applied to pilots' helmets, for example, return bright beams of light when

struck by the powerful searchlights used by search aircraft. These markers

may also be applied to other gear, such as life rafts and life vests. the Diamond Ordnance Fuze Laboratories where it was desired to conduct

full-scale field trials for studying the simultaneous effects of seven variables on the behavior of an ordnance device. An investigation involving all combinations of these variables would have required 2,592 trials. However, use of an experimental plan proposed by the Bureau resulted in a reduction of 75 percent in the number of necessary field trials to adequately investigate all seven factors. At the request of the Office of Naval Research, Bureau scientists visited and conferred with officials of the Aerojet Corporation at Azuza,

California, on various aspects of an experimental program being carried out under the sponsorship of the Navy. A report including recommended

improvements was made to the Office of Naval Research to aid them in the future development of this program.

Engine Laboratory Discontinued, During the year, the Bureau dis- continued work on full-scale multicylmder engines. The decision was

based on careful consideration of the small amount of work of this kind now required by other Government agencies, the nature of the work

in relation to other Bureau activities, and the critical need for the space involved by other projects of greater importance. The engine laboratory was started in World War I to aid the then infant automobile and aircraft industries. With the tremendous growth of these industries they now

support their own research, testing, and development programs.

132
This decision does not change the Bureau's activities in regard to maintenance of the standards for measurement of octane number,

improvement of methods of measurement, and other standardization

work involving fuels and lubricants. An example of the kind of work

to be continued is afforded by the investigation of the effect of altitude on measurement of octane number. This work conducted in 1955 has

resulted in a new set of correction factors that have been recently incorporated in the standard ASTM procedure for measurement of octane number.

Radio Propagation Services. An important part of the regular services provided to the public and to other Government agencies is the prediction

of the variations to be expected in communication characteristics, and

the collection, analysis, and distribution of ionospheric data on a national

and international basis. The selection of the best sky-wave frequencies

for communication purposes for a given transmission path depends upon

the time of day, season of the year, phase of the sunspot cycle, length of

the path, location of the path, as well as the conditions prevailing in the ionosphere over the path. This predictions work is a direct continuation of the effort made during the war to provide the Armed Services

with the latest available radio propagation information in usable form.

These predictions are widely used by organizations interested in short- wave radio communications, including the Armed Services and other U. S. Government agencies, numerous scientific and commercial organizations, and foreign governments. Because they are used to plan

frequency assignments and utilization in worldwide radio communications,

errors in prediction may result in poor communication for the user or

inefficient use of the limited radiofrequency spectrum available, with

concomitant serious military or economic losses. Regularly received

ionospheric sounding data together with indices of solar activity received

from associated solar observatories are used in preparing advance pre- , dictions of optimum frequencies for long-distance communication throughout the world. These predictions are prepared for each month and are published three months in advance (see appendix 5.6, page 144).

Besides the gradual changes in ionospheric characteristics with season and sunspot number, short -time disturbances associated with magnetic

storms at times seriously interfere with radio communications. These

disturbances are especially common in the important North Atlantic

and North Pacific regions. Two radio warning services are therefore operated for these regions. By observation of solar activity, disturbance

of the earth's magnetic field, and radio operating reports, the Bureau

is able to issue short-term warnings in anticipation of such disturbances.

Advance forecasts for 1 to 24 days ahead were issued regularly on a semiweekly basis, and medium-term forecasts for 24 hours ahead were made once a day. Short-term forecasts for a 6 -hour period were broadcast regularly from radio station WWV in Beltsville. Md., and from

WWVH in Maui, Hawaii.

133
5. Appendixes

5.1. Organization of the National Bureau of Standards*

Allen V. Astin, Director Associate Director for Chemistry

Wallace R. Brode

Associate Director for Physics

Robert D. Huntoon

Associate Director for Testing A. T. McPherson

Associate Director for Planning

Nicholas E. Golovin

Assistant Director for Administration R. S. Walleigh

Director Emeritus

Lyman J. Briggs

SCIENTIFIC AND TECHNICAL DIVISIONS AND

SECTIONS

ELECTRICITY AND ELECTRONICS, F. B. Silsbee, Chief

Resistance and Reactance, J. L. Thomas

Electron Tubes, C. P. Marsden, Jr. Electrical Instruments, F. M. Defandorf

Magnetic Measurements, I. L. Cooter, Acting

Dielectrics, J. D. Hoffman

Engineering Electronics, G. Shapiro, Acting

Electronic Instrumentation, C. Stansbury

Electrochemistry, W. J. Hamer

OPTICS AND METROLOGY, I. C. Gardner, Chief Photometry and Colorimetry, L. E. Barbrow

Optical Instruments, F. E. Washer

Photographic Technology, R. Davis

Length, L. V. Judson

Engineering Metrology, I. H. Fullmer

HEAT AND POWER, F. G. Brickwedde, Chief Temperature Physics, J. F. Swindells

Thermodynamics, C. W. Beckett

Cryogenic Physics, R. P. Hudson

Rheology and Lubrication, J. F. Swindells, Acting

Engine Fuels, F. L. Howard

ATOMIC AND RADIATION PHYSICS, L. S. Taylor, Chief Atomic Physics Laboratory

Spectroscopy, W. F. Meggers

Radiometry, E. K. Plyler Mass Spectrometry, F. L. Mohler

Solid State Physics, H. P. R. Frederikse

Electron Physics, L. L. Marton

Atomic Physics, L. M. Branscomb

*As of September 1956. 134
Radiation Physics Laboratory, HL O. YVyzkoff

Nuclear Physics, U. Fano

Radioactivity, W. B. Mann

X-rays, H. O. Wyckoff

Betatron, H. W. Koch

Nucleonic Instrumentation, L. Costrell

Radiological Equipment, S. W . Smith

Radiation Instruments Branch, Atomic Energy Commission, R. L. BUTENHOFF

CHEMISTRY, E. Wickers, Chief Organic Coatings, P. T. Howard

Surface Chemistry, W. W. Walton

Organic Chemistry, W. H. Smith

Analytical Chemistry, H. A. Bright

Inorganic Chemistry, R. Gilchrist

Electrodeposition, A. Brenner

Gas Chemistry, E. R. Weaver

Physical Chemistry, E. R. Smith

Thermochemistry, E. J. Prosen

Spectrochemistry, B. F. Scribner

Pure Substances, C. P. Saylor

MECHANICS, W. Ramberg, Chief Sound, R. K. Cook

Mechanical Instruments, E. C. Lloyd

Fluid Mechanics, G. B. Schubauer

Engineering Mechanics, B. L. Wilson

Mass and Scale, H. H. Russell, Acting

Capacity, Density, and Fluid Meters, H. S. Bean

Combustion Controls, F. R. Caldwell

ORGANIC AND FIBROUS

Rubber, L. A. Wood

Textiles, W. D. Appel

Paper, R. B. Hobbs

Leather, J. R. Kanagy

MATERIALS, G. M. Kline, Chief

Testing and Specifications, R. D. Stiehler

Polymer Structure, N. Bekkedahl

Organic Plastics, F. W. Reinhart

Dental Research, W. T. Sweeney

METALLURGY, J. I. Hoffman, Chief Thermal Metallurgy, T. G. Digges Mechanical Metallurgy, J. A. Bennett

Chemical Metallurgy, L. L. Wyman Corrosion, G. A. Ellinger

MINERAL PRODUCTS, I. C. Schoonover, Chief Engineering Ceramics, M. D. Burdick

Glass, C. H. Hahner

Refractories, S. Zerfoss

Enameled Metals, W. N. Harrison

Concreting Materials, R. L. Blaine

Constitution and Microstructure, H. F. McMuRDIE

BUILDING TECHNOLOGY, D. E. Parsons, Chief

Structural Engineering, D. E. Parsons Codes and Specifications, J. A. Dickin

Fire Protection, A. F. Robertson son

Heating and Air Conditioning, R. S. Dill

Floor, Roof, and Wall Coverings, H. R. Snoke

APPLIED MATHEMATICS, E. W. Cannon, Chief Numerical Analysis, J. Todd Statistical Engineering, C. Eisenhart

Computation, M. Abramowitz Mathematical Physics, R. F. Dressler

DATA PROCESSING SYSTEMS, S. N. Alexander, Chief SEAC Engineering Group, P. D. Shupe,

Jr. Components and Techniques, R. D. Elbourn

Digital Circuitry, S. Greenwald

Digital Systems, A. L. Liener

Analog Systems, H. K. Skramstad

Application Engineering, S. N. Alexander (Acting)

135
OFFICE OF PUBLICATIONS, Wallace R. Brode, Chief OFFICE OF WEIGHTS AND MEASURES, W. S. Bussey, Chief OFFICE OF BASIC INSTRUMENTATION, W. A. Wildhack, Chief OFFICE OF TECHNICAL INFORMATION, W. R. Tilley, Chief ADMINISTRATIVE DIVISIONS

Accounting, P. R. McClenon Supply, G. B. Kefover

Personnel, G. R. Porter Management Planning Staff, Ivan Asay

Administrative Services, H. P. Dalzell Budget, N. L. Christeller

Shops, F. P. Brown Plant, C. A. Dieman

BOULDER LABORATORIES, F. W. Brown, Director CRYOGENIC ENGINEERING, R. B. Scott, Chief Cryogenic Equipment, R. B. Jacobs

Cryogenic Processes, B. W. Birmingham

Properties of Materials, R. J. Corruccini Gas Liquefaction, V. J. Johnson

RADIO PROPAGATION PHYSICS, R. J. Slutz, Chief Upper Atmosphere Research, T. N. Gautier

Ionospheric Research, R. C. Kirby

Regular Propagation Services, W. B. Chadwick

Ionospheric Research (Boulder), R. C. Kirby

Sun Earth Relationships, A. H. Shapley

RADIO PROPAGATION ENGINEERING, K. A. Norton, Chief Data Reduction Instrumentation, W. E. Johnson

Modulation Systems, A. D. Watt

Navigation Systems, G. Hefley

Radio Noise, W. Q. Crichlow

Tropospheric Measurements, C. F. Peterson

Tropospheric Analysis, P. L. Rice

Radio Systems Application Engineering, R. S. Kirby

RADIO STANDARDS, H. A. Thomas, Chief

Asst. Chief for Radio Frequencies, W. D. George

Asst. Chief for Microwave Frequencies, D. M. Kerns

High Frequency Electrical Standards, M. C. Selby

Radio Broadcast Service, A. H. Morgan

High Frequency Impedance Standards, J. L. Dalke

Calibration Center, H. W. Lance

Microwave Physics, D. M. Kerns

Microwave Circuit Standards, R. W. Beatty

ADMINISTRATIVE DIVISION, S. W. J. Welch

NATIONAL BUREAU OF STANDARDS

FIELD ESTABLISHMENTS

National Bureau of Standards, Boulder, Colo. Cheyenne Mt. Field Station, Colorado Springs, Colo. Radio Transmitting Station WWV, Beltsville, Md.

Radio Propagation Laboratory, Sterling, Va.

136
Radio Propagation Field Stations. Anchorage, Alaska

Carthage, 111. Fort Belvoir, Va. Front Royal, Va. Guam

Gunbarrel Hill, Longmont, Colo. Lamp Inspector, Brookline 46, Mass.

Visual Landing Aids Field Lab., Areata, Calif. Master Railway Track Scale Depot, Clearing, 111. Materials Testing Laboratories Allentown, Pa. San Francisco, Calif. Denver, Colo. Seattle, Wash.

Narsarssuak, Greenland Panama Canal Zone

Point Barrow, Alaska Puerto Rico Puunene Maui, T. H. (Station WWVH)

5.2. Fiscal Data on NBS Program

PROGRAM AND SOURCE OF FINANCING

Supported by NBS Appropriations

Operating Program:

Expenses

Construction and Facilities Programs

Plant and Equipment

Construction of Laboratories Total

Total, NBS Appropriations

Supported by Other Agencies

Department of Defense and AEC

Other Agencies

Total, Other Agencies Total Program

Obligations Incurred

Fiscal Year 1956

$ 7, 349, 478

890, 193

66, 575

956, 768

8, 306, 246

12, 024, 500

1, 667, 100 13,691,600

21,997, 846

5.3. Advisory Committees

STATUTORY VISITING COMMITTEE

[Reports annually to Secretary of Commerce on NBS activities (Dates indicate expiration of appointment.)] Professor J. H. Van Vleck, Dean, Division of Applied Science, Harvard University

(1956) Dr. M. J. Kelly, President, Bell Telephone Laboratories, Inc. (1957) Dr. Clyde E. Williams, President, Battelle Memorial Institute (1958) Dr. Crawford H. Greenewalt, President, E. I. du Pont de Nemours & Co. (1959) Dr. Detlev W. Bronk, President, National Academy of Sciences (1960) Technical Advisory Committees

[Designated by leading scientific and technical societies to advise NBS Director in specific technical areas. Members listed served during fiscal year 1956.] AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS

Dr. Ralph Bown, Maplewood, N. J. Dr. C. G. Suits, General Electric Company

Dean F. E. Terman, Stanford University Dr. E. W. Engstrom, Radio Corpoiation of America

Mr. Robert C. Sprague, Sprague Electric Company

Dr. J. A. Hutcheson, Westinghouse Electric Corporation

137
INSTITUTE OF RADIO ENGINEERS

Mr. Harold O. Peterson, Radio Corporation of America Dr. A. W. Straiton, University of Texas Professor Henry G. Booker, Cornell University

Mr. Stuart L. Bailey, Jansky & Bailey

Dean William L. Everitt, University of Illinois Professor A. H. Waynick, Pennsylvania State University

AMERICAN INSTITUTE OF PHYSICS

Professor F. Seitz, University of Illinois Professor D. M. Dennison, University of Michigan Dr. E. M. Purcell, Harvard University

Professor J. A. Bearden, Johns Hopkins University Dr. M. Deutsch, Massachusetts Institute of Technology

Professor R. B. Lindsay, Brown University

Dean R. A. Sawyer, University of Michigan

Professor Cecil T. Lane, Yale University

Professor Mark W. Zemansky, City College of New York

Professor A. 0. C. ]\ier, Lniversity of Minnesota Dr. H. M. Parker, General Electric Company

POLICY COMMITTEE FOR MATHEMATICS

Dean Mina Rees, Hunter College

Professor Philip M. Morse, Massachusetts Institute of Technology

Professor David Blackwell, University of California Professor A. H. Taub, University of Illinois Professor Mark Kac, Cornell University Dr. E. U. Condon, Washington University

AMERICAN INSTITUTE OF MINING AND METALLURGICAL

ENGINEERS

Dr. Walter A. Dean, Aluminum Company of America

Mr. Earle E. Schumacher, Bell Telephone Laboratories Dr. Maxwell Gensamer, Columbia University

Mr. Clarence E. Sims, Battelle Memorial Institute Dr. E. C. Smith, Republic Steel Corporation

Professor M. G. Fontana, Ohio State University

AMERICAN CHEMICAL SOCIETY

Professor N. Howell Furman, Princeton University

Professor C. S. Marvel, University of Illinois Dr. Milton Harris, Harris Research Laboratories Dr. J. R. Ruhoff, Mallinckrodt Chemical Works

Dr. Norman A. Shepard, Stamford, Conn. Professor Farrington Daniels, University of Wisconsin

AMERICAN CERAMIC SOCIETY

Mr. E. P. McNamara, Cambridge Tile Company

Dean Elburt Osburn, Pennsylvania State University

Mr. Wayne Deringer, A. 0. Smith Corporation Dr. Allan Bates, Portland Cement Association Dr. A. C. Siefert, Owens-Corning Glass Corporation

Mr. Joe W. Kruson, Big Savage Refractories Corporation

Mr. Paul V. Johnson, Structural Clay Products Research Foundation

Mr. Harry W. Thiemecke, Homer Laughlin China Company

Mr. Hubert Woods, Portland Cement Association

138
AMERICAN SOCIETY OF MECHANICAL ENGINEERS

Mr. James W. Parker, Ann Arbor, Michigan

Professor Dana Young, Yale University

Professor S. R. Beitler, Ohio State University

Professor C. Harold Berry, Harvard University

Mr. Paul V. Miller, Taft Pierce Manufacturing Company

NATIONAL CONFERENCE ON WEIGHTS AND MEASURES

Mr. John P. McBride, Director of Standards and Necessaries of Life, Boston, Mass. Mr. Bruns H. Dreese, Hobart Manufacturing Company

Mr. Charles M. Fuller, Sealer of Weights and Measures, Los Angeles, California Mr. Harry J. Kennedy, Continental Oil Company

Mr. Seth T. Shaw, Safeway Stores, Inc. Mr. C. J. McCaffrey, Ralph N. Brodie Company, Inc. AMERICAN SOCIETY OF CIVIL ENGINEERS

Dr. G. H. Hickox, National Science Foundation Dr. A. T. Ippen, Massachusetts Institute of Technology

Mr. Raymond C. Reese, Toledo, Ohio

AMERICAN STANDARDS ASSOCIATION

Mr. H. Thomas Hallowell, Jr., Standard Pressed Steel Company

Mr. John R. Town send, Sandia Corporation

Mr. Arthur S. Johnson, American Mutual Liability Insurance Company

Vice Admiral G. F. Hussey, Jr., USN (Ret), American Standards Association Mr. Cyril Ainsworth, American Standards Association Mr. J. L. Cranwell, Pennsylvania Railroad Company

AMERICAN SOCIETY FOR TESTING MATERIALS

Mr. Norman L. Mochel, Westinghouse Corporation Dr. A. Allan Bates, Portland Cement Association Mr. T. A. Boyd, General Motors Corporation

Mr. Aiken w . Fisher, Fisher Scientific Company

Mr. R. E. Peterson, Westinghouse Research Laboratories 5.4. Awards and Honors

Recognition of the Bureau's contributions to science and technology often takes

the form of awards and honors from academic, industrial, and professional groups. The following list reflects such recognition bestowed on Bureau staff members during

the fiscal year 1956. RECIPIENT

Barbrow, Louis E. Bates, Roger C. Bright, Harry A. Broida, Dr. Herpert P. Brompacher, Dr. William G. Fano, Dr. Uco

Gardner, Dr. Irvine C. Leaderman, Dr. Herpert

Marton, Dr. L. McBurney, Dr. John W.

Newman, Dr. Sanford B. and Wolock, Dr. Irvin Rodney, Dr. William S. Trees, Dr. Richard E.

Tsai, Dr. Donald H.

HONOR

Elected to Fellow

Hillebrand Prize Award of Merit Arthur S. Flemming Award

Honor Award

Rockefeller Public Service Award

Elected to Fellow Bingham Medal for 1955

Fulbright Fellowship Foreign Member

Award of Merit

First Prize for General Photomicrographs (Nonmetallic) Awarded Fellowship

Rockefeller Public Service Award

Oil and Gas Power Division Award

SOURCE

Illuminating Engineering Society Chemical Society of Washington

American Society for Testing Materials Junior Chamber of Commerce of W ashington American Society of Mechanical

Engineers Administered by Princeton University

as a national trust Society of Photographic Engineers

Society of Rheology

Dept. of State Royal Academy of Belgium American Society for Testing

Materials American Society for Testing Materials, 10th Photographic Exhibit John Simon Guggenheim Memorial

Foundation

Administered by Princeton University as a national trust American Society of Mechanical

Engineers

139
HONORED BY U. S. DEPARTMENT OF COMMERCE

RECIPIENT

Achenpach, Paul R. Florman, Edwin F. Hoffman, Dr. James I. Jensen, Malcolm W.

Judson, Dr. Lewis V. Leaderman, Dr. Herbert

Prosen, Edward J. Robinson, Henry E. Schiefer, Dr. Herbert F. Schubauer, Dr. Galen B. Silsbee, Dr. Francis B. Smith, Ralph W.

Snyder, Carl F. Vacher, Herbert C. Wall, Dr. Leo A. Webb, Earl F. Radio Research Group

Bailey, Dana K.

Bateman, Ross

Kirby, Richard C.

HONOR FIELD OF WORK

Meritorious Service Award Heating and Air Conditioning

Meritorious Service Award Radio Propagation

Exceptional Service Award Surface Chemistry

Meritorious Service Award Weights and Measures Administration

Meritorious Service Award Length Standards

Meritorious Service Award Structure of Polymers

Meritorious Service Award Thermochemistry

Meritorious Service Award Heating and Air Conditioning Exceptional Service Award Textile Science and Technology

Exceptional Service Award Basic Aerodynamics

Exceptional Service Award Electricity and Electronics Meritorious Service Award Weights and Measures Administration

Meritorious Service Award Organic Chemistry

Meritorious Service Award Mechanical Metallurgy

Meritorious Service Award Polymer Structure Meritorious Service Award Optical Instruments

Exceptional Service Award Ionospheric Scatter

Recognition in the form of employee Contribution Cash Awards (Superior Per formance and Special Acts or Services) was given 147 Bureau employees. Seventy

five employees were recipients of cash awards for suggestions adopted by the Bureau.

5.5. Public Law 940 Authorizing Retention of^Fees

Public Law 940—84th Congress

Chapter 906—2d Session

S. 2060

AN ACT All 70 Stat. 959. To amend the Act of March 3, 1901 (31 Stat. 1449) as amended, to incorporate

in the Organic Act of the National Bureau of Standards the authority to use

the Working Capital Fund, and to permit certain improvements in fiscal practices. Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the Act

entitled "An Act to establish the National Bureau of Standards",

approved March 3, 1901, as amended, is amended by striking out

sections 7 and 8 and inserting in lieu thereof the following sections: "Sec. 7. The Secretary shall charge for services performed under

the authority of section 3 of this Act, except in cases where he

determines that the interest of the Government would be best served by waiving the charge. Such charges may be based upon

fixed prices or cost. The appropriation or fund bearing the cost of the services may be reimbursed, or the Secretary may require advance payment subject to such adjustment on completion of the work as may be agreed upon.

"Sec. 8. In the absence of specific agreement to the contrary,

additional facilities, including equipment, purchased pursuant to the performance of services authorized by section 3 of this Act

shall become the property of the Department of Commerce."

Sec. 2. Such Act is further amended by striking out sections 11,

12, and 13 and inserting in lieu thereof the following sections: "Sec. 11. (a) The Secretary of Commerce is authorized to accept and utilize gifts or bequests of real or personal property for the purpose of aiding and facilitating the work authorized therein. "(b) For the purpose of Federal income, estate, and gift taxes,

gifts and bequests accepted by the Secretary of Commerce under the

authority of this Act shall be deemed to be gifts and bequests to or

for the use of the United States. "Sec. 12. (a) The National Bureau of Standards is authorized to

utilize in the performance of its functions the Working Capital Fund

established by the Act of June 29, 1950 (64 Stat. 275), and additional amounts as from time to time may be required for the purposes of said fund are hereby authorized to be appropriated.

National Bureau c Standards.

31 Stat. 1450. 15 USC 276.

Service charges.

Ownership of

facilities. 15 USC 273.

64 Stat. 373. 15 USC 278a-278c.

Gifts and bequests.

Working Capital Fund.

64 Stat. 279.

140
"(b) The working capital of the fund shall be available for obligation and payment for any activities authorized by this Act, as amended, and for any activities for which provision is made in the appropriations which reimburse the fund.

"(c) In the performance of authorized activities, the Working

Capital Fund shall be available and may be reimbursed for expenses

of hire of automobile, hire of consultants, and travel to meetings, to the extent that such expenses are authorized for the appropriations

of the Department of Commerce.

"(d) The fund may be credited with advances and reimburse- ments, including receipts from non-Federal sources, for services 15 USC 273 performed under the authority of section 3 of this Act.

"(e) As used in this Act the term 'cost' shall be construed to include directly related expenses and appropriate charges for

indirect and administrative expenses.

"(f) The amount of any earned net income resulting from the

operation of the fund at the close of each fiscal year shall be paid

into the general fund of the Treasury: Provided, That such earned

net income may be applied first to restore any prior impairment of the fund." Approved August 3, 1956.

5.6. Publications

Publications in the Bureau's Series Journal of Research. The Journal, issued monthly, presents research papers in various fields of physics, mathematics, chemistry, metallurgy, and the engineering

sciences. (Annual subscription: domestic, $4.00; $1.25 additional for foreign mailing.) Research Papers published from July 1955 to June 1956, inclusive: Volume 55, July—December 1955

2599. Some properties of a glass used in paper manufacture. Martin J. O'Leary

and Donald Hubbard.

2600. Adsorption of nitrogen on carbon adsorbents at low pressures between 69° and

90° K. Juan de Dios Lopez -Gonzalez, Frank G. Carpenter, and Victor R. Deitz. 2601. Stress-strain relationships in yarns subjected to rapid impact loading: 3. Effect of wave propagation. Jack C. Smith, Frank L. McCrackin, and Herbert F. Schiefer. 2602. Thermal expansion and phase transformations of low-expanding cobalt-iron- chromium alloys. Peter Hidnert and Richard K. Kirby.

2603. Vapor pressures of the methanes. George T. Armstrong, F. G. Brickwedde,

and R. B. Scott. 2604. Data on the atomic form factor: Computation and survey. Ann T. Nelms

and Irwin Oppenheim.

2605. Absolute calibration of the National Bureau of Standards photoneutron standard: I. J. A. Dejuren, D. W. Padgett, and L. F. Curtiss. 2606. A fast responding electric hygrometer. Arnold Wexler, Samuel B. Garfinkel,

Frank E. Jones, Saburo Hasegawa, and Albert Krinsky.

2607. A simplified method of measuring the marginal powers of spectacle lenses. Francis E. Washer.

2608. Thermodynamic properties of the alkali metals. William H. Evans, Rosemary

Jacobson, Thomas R. Munson, and Donald D. Wagman.

2609. Arc and spark spectra of ruthenium. Karl G. Kessler and William F. Meggers.

2610. Heat capacity of some butadiene-styrene copolymers from 0° to 330° K.

George T. Furukawa, Robert E. McCoskey, and Martin L. Reiily. 2611. Setting reaction of zinc oxide and eugenol. Henry J. Copeland, Jr., Gerhard

M. Brauer, W. T. Sweeney, and A. F. Forziati. 2612. Development of a photoresist for etching designs in glass. Chester 1. Pope

and Raymond Davis.

2613. Preferred orientation in stark rubber. C. J. Newton, L. Mandelkern, and D. E. Roberts.

2614. Thermodynamic properties of some gaseous halogen compounds. William H.

Evans, Thomas R. Munson, and Donald D. Wagman.

2615. Atomic negative-ion-photodetachment cross-section and affinity measurements. Stephen J. Smith and Lewis M. Branscomb.

408368—57 11 141
2616. A study of the final stages of the austenite to martensite transformation in SAE 1050 steel. Melvin R. Meyerson and Samuel J. Rosenberg.

2617. Infrared absorption and emission spectra of carbon monoxide in the region from

4 to 6 microns. Earle K. Plyler, Lamdin R. Blaine, and Eugene D. Tidwell. 2618. Specific heats of collagen and leather. Joseph R. Kanagy.

2619. pH values of the Clark and Lubs buffer solutions at 25° C. Vincent E. Bower

and Roger G. Bates. 2620. Heat capacity; heats of fusion, vaporization, and transition; and vapor pressure

of .Y-dimethylaminodiborane, (CHsXABoHs. George T. Furukawa, Robert E. McCoskey, Martin L. Reilly, and Ann W. Harman.

2621. Phase equilibrium relations in the systems titania-niobia and zirconia-niobia. R. S. Roth and L. W. Coughanour.

2622. Synthesis of a fluoro talc and attempted synthesis of fluoro chrysotile and

fiuoro anthophyllite. Alvin ^ an Yalkenburg, Jr. 2623. Determination of natural rubber in GR-S—natural rubber vulcanizates by

infrared spectroscopy. Max Tryon, Emanuel Horowitz, and John Mandel.

2624. Thermal degradation of polychlorotrifluoroethylene, poly-a, /3, /3-trifluorostyrene, and poly-p-xylylene in a vacuum. S. L. Madorsky and S. Straus. 2625. Infrared transmittance of some calcium aluminate and germanate glasses. Jack M. Florence, Francis W. Glaze, and Mason H. Black.

2626. Properties of piezoelectric ceramics in the solid -solution series lead titanate—lead zirconate—lead oxide: tin oxide and lead titanate-lead hafnate. B. Jaffe, R. S. Roth, and S. Marzullo.

2627. Heat capacity, heats of fusion and vaporization, and vapor pressure of deca- borane (BioHh). George T. Furukawa and Rita P. Park.

2628. Preparation of titanium tetrachloride of high purity. W. Stanley Clabaugh, Robert T. Leslie, and Raleigh Gilchrist. 2629. Liquid-vapor phase equilibrium in solutions of oxygen and nitrogen at pres- sures below one atmosphere. George T. Armstrong, Jack M. Goldstein, and D.

Ellis Roberts.

2630. Precise measurement of wavelengths in infrared spectra. Earle K. Plyler, Lamdin R. Blaine, and Eugene D. Tidwell. 2631. Ideal gas thermodynamic functions of the isotopic hydrogen sulfides. Lester Haar, Joe C. Bradley, and Abraham S. Friedman.

2632. Measurement of field distortion in free-air ionization chambers by analog method. William Miller and Robert J. Kennedy.

2633. The first spectrum of barium, Ba I. Henry Norris Russell and Charlotte E. Moore.

2634. Compressibilities of long-chain normal hydrocarbons. C. E. Weir and J. D. Hoffman.

2635. Absolute calibration of the INational Bureau of Standards photoneutron standard: II. Absorption in manganese sulfate. James De Juren and Jack Chin.

2636. A new Bunsen-type calorimeter. Ralph S. Jessup. 2637. Mass spectra of thermal degradation products of polymers. Paul Bradt and

Fred L. Mohler.

2638. Heats of combustion of Liquid n-hexadecane, 1-hexadecene, n-decylbenzene,

n-decylcyclohexane, n-decylcvclopentane, and the variation of heat of combustion

with chain length. Frances Maron Fraser and Edward J. Prosen.

2639. Computation of atomic energy levels: Spectrum of singly-ionized tantalum

(Ta n). R. E. Trees, W. F. Cahilf, and P. Rabinowitz.

2640. Reflection and transmission of gamma radiation by barriers: Monte Carlo cal- culation by a collision-density method. Martin J. Berger. Volume 56, January—June 1956

2641. Dielectric constant of water from 0° to 100° C. C. G. Malmberg and A. A. Maryott.

2642. A colorimeter for measuring the power in a high-energy X-ray beam. John

McElhinnev, Bernard Zendle, and Steve Domen.

2643. Pyrochiore-type compounds containing double oxides of trivalent and tetravalent ions. Robert S. Roth.

2644. Thermal decomposition of polytetrafluoroethylene in various gaseous atmospheres. L. A. Wall and J. D. Michaelsen.

2645. Abscissas and weights for Gaussian quadratures of high order. P. Davis and

P. Rabinowitz.

2646. Behavior of cements and related materials under hydrostatic pressures up to 10,000 atmospheres. C. E. Weir, C. M. Hunt, and R. L. Blaine. 2647. Formulas for inverse osculatory interpolation. Herbert E. Salzer. 2648. Residual entropy of linear polymers. H. I\ . V. Temperley.

142
2649. Molecular weights of thermally degraded polymethyl methacrylate. Victor E.

Hart.

2650. Thermal expansion of binary alkaline-earth borate glasses. Herman F. Shermer.

2651. Dielectric relaxation for a three-dimensional rotator in a crystalline field: theory for a general six-site model. Benjamin M. Axilrod. 2652. A matrix with real characteristic roots. Karl Goldberg.

2653. Reflection and transmission of gamma radiation by barriers: semianalytic

Monte Carlo calculation. Martin J. Berger and John Doggett.

2654. An examination of the helium vapor-pressure scale of temperature using a magnetic thermometer. E. Ambler and R. P. Hudson.

2655. Calculation of thermodynamic functions for polyatomic molecules. Harold W.

Woolley.

2656. Penetration of gamma radiation from a plane monodirectional oblique source. Martin J. Berger.

2657. A re-entrant cavity for measurement of complex permeability in the very-highfrequency region. R. D. Harrington, R. C. Powell, and P. H. Haas.

2658. Fundamental factors controlling electrical resistivity in vitreous ternary lead

silicates. Simon W. Strauss, Dwight G. Moore, William N. Harrison, and Lloyd

E. Richards.

2659. Some factors affecting the precision of polarographic half-wave potential measurements. John K. Taylor and Stanley W. Smith.

2660. Infrared measurements from 50 to 125 microns. Earle K. Plyler and Nicolo

Acquista.

2661. Surface tension of molten glasses in the system barium oxide-boric oxide-silica. Herman F. Shermer.

2662. Relationship between crystal orientation and stress -corrosion cracking in alpha

and beta brasses. Hugh L. Logan.

2663. New descriptions and analyses of the third and fourth spectra of zirconium, Zr in and Zr iv. C. C. Kiess. 2664. Frequency conversion with positive nonlinear resistors. Chester H. Page.

2665. Electrical resistivity of vitreous ternary lithium sodium silicates. Simon W.

Strauss. 2666. Isothermal compressibilities of alkaline earth oxides at 21° C. C. E. Weir.

2667. Improved synthesis of sodium D-glucuronate-6-C 14 and of D-glucose-6-C 14

. R.

Schaffer and H. S. Isbell. 2668. Ideal gas thermodynamic functions of the isotopic hydrogen cyanides. Joe C.

Bradley, Lester Haar, and Abraham S. Friedman.

2669. Surge voltage breakdown of air in a nonuniform field. J. H. Park and H. N.

Cones.

2670. Index of refraction and particle size as factors in the infrared spectrophotometry

of polyvinyl chloride. Mary Reiney Harvey, James E. Stewart, and Bernard G. Achhammer.

2671. Radiation from a vertical antenna over a curved stratified ground. James R.

Wait.

2672. Characteristics of an image-forming system. Roland V. Shack.

2673. Advances in the design and application of the radiofrequency permeameter.

Alvin L. Rasmussen, Albert W. Enfield, and Alfred Hess. 2674. A new computer for calculating the water content of gases. A. W. Diniak and

E. R. Weaver.

2675. Vibrational constants of acetylene-da. Harry C. Allen, Jr., L. R. Blaine, and

Earle K. Plyler. 2676. Heat capacity of polyisobutylene from 0° to 380° K. George T. Furukawa

and Martin L. Reilly. 2677. Preparation of barium titanyl oxalate tetrahydrate for conversion to barium

titanate of high purity. W. Stanley Clabaugh, Edward M. Swiggard, and Raleigh

Gilchrist. 2678. A five-band recording spectroradiometer. C. S. McCamy.

2679. Polarographic determination of lead and cadmium in zinc-base alloys, using

electrolytic separations at controlled potential. John K. Taylor and Stanley W.

Smith.

2680. Calcium hydroxide as a highly alkaline pH standard. Roger G. Bates, Vincent

E. Bower, and Edgar R. Smith.

2681. Heats of formation of hexacalcium dialumino ferrite and dicalcium ferrite. E. S. Newman and Roald Hoffman.

2682. Response of a sodium-iodide scintillation spectrometer to 10- to 20-millionelectron-volt electrons and X-rays. H. W. Koch and J. M. Wyckoff.

2683. Hydrogarnet formation in the system lime-alumina-silica-waler. Elmer T.

Carlson.

143
2684. Infrared absorption spectrum of trimethylborane. James E. Stewart.

2685. Pyrolysis of cellulose in a vacuum. S. L. Madorsky, V. E. Hart, and S. Straus.

2686. Response function of thallium-activated sodium-iodide scintillation counters. Martin J. Berger and J. Doggett.

Technical News Bulletin. Summaries of current research at the Bureau are published each month in the Technical News Bulletin. Lists of Bureau publications

during the preceding month are given. (Annual subscription: domestic, SI. 00; 35

cents additional for foreign mailing.) Basic Radio Propagation Predictions. The Predictions provide the information

necessary for calculating the best frequencies for communication between any two

points in the world at any time during the given month. The data are important to

all users of long-range radio communications and navigation, including broadcasting,

airline, steamship, and wireless services, as well as to investigators of radio propagation and the ionosphere. Each issue, covering a period of 1 month, is released 3 months in advance and contains 16 pages, including pertinent charts, drawings, and

tables. (Annual subscription: domestic, S1.00; 25 cents additional for foreign mailing.)

Circulars. Compilations of information on various subjects related to the Bureau's

scientific and technical activities. Results of Bureau studies and data of general

interest from other sources are included. 539: Volume \ . Standard X-ray Diffraction Powder Patterns. Howard E. Swanson' Nancy T. Gilfrich, and George M. Ugrinic.

553. The ISCC-NBS Method of Designating Colors and a Dictionary of Color Names. Kenneth L. Kelly and Deane B. Judd.

557. Worldwide Radio Noise Levels Expected in the Frequency Band 10 Kilocvcles

to 100 Megacycles. W. Q. Crichlow, D. F. Smith, R. N. Morton, and W. R.

Corliss. 562. Bibliography of Research on Deuterium and Tritium Compounds 1945 to 1952. Lawrence M. Brown, Abraham S. Friedman, and Charles W. Beckett.

563. Periodicals and Serials Received in the Library of the National Bureau of Standards, April 1955. Natalie J. Hopper and Dorothy H. Pepperman.

564. Tables of Thermal Properties of Gases. Joseph Hilsenrath, Charles W. Beckett, William S. Benedict, Lilla Fano, Harold J. Hoge, Joseph F. Masi, Ralph L. Nuttall, Yeram S. Touloukian, and Harold W. Woolley.

565. Techniques for Ruling and Etching Precise Scales in Glass and Their Reproduction by Photoetching With a New Light-Sensitive Resist. Raymond Davis and

Chester I. Pope.

566. Bibliography of Solid Adsorbents 1943 to 1953. Victor R. Deitz.

567. Guide to Instrumentation Literature. W. G. Brombacher, Julian F. Smith, and

Lyman M. Van der Pyl.

568. High-Temperature Reactions of Uranium Dioxide With Various Metal Oxides.

S. M. Lang, F. P. Knudsen, C. L. Fillmore, and R. S. Roth.

569. Fused-Quartz Fibers. A Survey of Properties, Applications, and Production Methods. Nancy J. Tighe.

570. Units and Svstems of Weights and Measures. Their Origin, Development, and

Present Status. Lewis V. Judson.

571. Electron Physics Tables. L. Martonj C. Marton, and W. G. Hall. 572. Calibration of Line Standards of Length and Measuring Tapes at the National Bureau of Standards. Lewis V. Judson.

573. Phase of the Low Radiofrequency Ground Wave. J. R. Johler, W. J. Kellar, and L. C. Walters.

574. Amplitude and Phase Curves for Ground-Wave Propagation in the Band 200

Cycles per Second to 500 Kilocycles. James R. Wait and H. Herbert Howe.

Handbooks. Recommended codes of engineering and industrial practice (including

safety codes) developed in cooperation with interested industries, professional organizations, and regulatory bodies. 44—2d Edition 1955. Specifications, Tolerances, and Regulations for Commercial

Weighing and Measuring Devices.

60. X-ray Protection.

61. Regulation of Radiation Exposure by Legislative Means.

144
Building Materials and Structures Reports. Results of Bureau investigations of building materials and techniques. 144 Supplement. Sound Insulation of Wall, Floor, and Door Constructions. Richard

V. Waterhouse.

145. Fire Effects and Fire Control in Nitrocellulose Photographic-Film Storage.

J. V. Ryan, J. W. Cummings, and A. C. Hutton.

146. Plasticity and Water Retentivity of Hydrated Limes for Structural Purposes. Ernest M. Levin, Walter F. Clarke, and Lansing S. Wells. Applied Mathematics Series. Mathematical tables, manuals, and studies.

45. Table of Hyperbolic Sines and Cosines.

46. Table of the Descending Exponential.

Miscellaneous Publications. Other types of materials, including charts, administrative pamphlets, directories, annual reports of the Bureau, and conference reports. 214. Units of Weight and Measure (United States Customary and Metric) Definitions and Tables of Equivalents. L. V. Judson.

215. Hydraulic Research in the United States, 1955. Helen K. Middleton.

216. Report of the 49th National Conference on Weights and Measures 1955.

217. Annual Report 1955.Publications in Outside Journals*

Abramowitz, M., and Cahill, W. F., On the vibration of a square clamped plate,

J. Assoc. Computing Machinery 2, No. 3, 162 (July 1955). Agy, V., Ionospheric effects produced by solar flare radiation, Phys. Rev. 102, 917 (May 1956). Alexander, S. N., An evaluation of electronic data processing equipment, Proc. Automatic Data Processing Conference (Harvard Graduate School of Business Administration, Sept. 1955). Alexander, S. N., Progress report on automatic data processing in Government (1956) (Univ. Mich. Press, June 1956). Alexander, S. N., Machines for retrieving and correlating recorded information (Western Reserve Univ. Press, Jan. 1956). Alexander, S. N., European experience with electronic computers, First Proc, Electronics in Management (American Univ., Nov. 1955).

Allen, H. C, Cross, P. C, Plyler, E. K., and Blaine, L. R., Infrared spectrum of hydrogen sulfide from 2200-2800 cm"1

, J. Chem. Phys. 24, No. 1, 35 (Jan. 1956).

Allen, H. C, Tidwell, E. D., and Plyler, E. K., Vibrational energy of deuterium cyanide,

J. Chem. Phys. 23, No. 7, 1356 (July 1955). Ambler, E., Hudson, R. P., and Temmer, G. M., Alignment of three rare-earth isotopes, Bull. Inter. Inst. Refrig., Commun. 142, 255 (Sept. 2-8, 1955). Ambler, E., and Hudson, R. P., Magnetic cooling, Proc. Phys. Soc. (London) 18, 251

(1955). Ambler, E., and Hudson, R. P., Measurements on the saturation vapour pressure of

liquid helium in the range 1.4° —4.2° K, Bull. Inter. Inst. Refrig., Commun. 147, 605 (Sept. 1955). Ambler, E., and Hudson, R. P., New materials for magnetic cooling and thermometry

below 1°K, Phys. Rev. 102, 916 (May 1956). Ambler, E., Hudson, R. P., and Temmer, G. M., Alignment of three odd-A rare-earth

nuclei, Phys. Rev. 101, 1956 (1956). Antosiewicz, H. A., A theorem on alternatives for pairs of matrices, Pac. J. Math. 5, Suppl. 1, 641-642 (1955). Antosiewicz, H. A., Stable systems of differential equations with integrable forcing term, J. London Math. Soc. 31, 208-212 (1956). Antosiewicz, H. A., Analytic study of war games, Naval Res. Logistics, Office of Naval Research 2, No. 3, 181 (Sept. 1955). Antosiewicz, H. A., On non-linear differential equations of the second order with

integrable forcing term, J. London Math. Soc. 30 (1955). Appel, W. D., International methods for testing colorfastness of textiles, Mag. of Standards 26, No. 2, 44 (1955).

*For completeness, a few references to publications issued previous to July 1955 are included.

145
Appel, W. D., Textiles at the National Bureau of Standards, Proc. Am. Assoc. Textile Chemists Colorists 44, No. 23, 795 (Nov. 1955). Astin, A. V-, Future of office and factory automation, Interpreter 1-10 (March 1956). Astin, A. Physical standards for the electronics industry, Signal 10, No. 5, 45 (May-June 1956). Astin, A. V., A brief look at the history of automation, Signal (March-April 1956). Astin, A. V., Standards for electronics, Proc. National Electronics Conference (Oct. 1955) . Astin, A. \ ., Metrology and production, Ordnance 40, No. 216, 973 (May-June 1956).

Attix, F. H., and Spencer, L. V., A theory of cavity ionization, Radiol. Research 3, 239 (Nov. 1955).

Barsis, A. P., and McGavin, R. E., Report on comparative 100 Mc measurements for three transmitting antenna heights, Trans. IRE AP-4, 168-174 (April 1956). Bass, A. M., and Broida, H. P., Spectra emitted from solid nitrogen condensed at

4.2° K from a gas discharge, Phys. Rev. 101, 1740 (March 1956). Bay, Z. L., Millimicrosecond coincidence circuits, N ucleonics 14, N o. 4, 56 (April 1956). Bean, B. R., Some meteorological effects on scattered radio waves, IRE Trans, on

Communications Systems CS-4, No. 1, 32-38 (March 1956). Beckers, A., and Levedahl, W. J., Mechanism of autoignition in benzene-air mixtures,

Ind. Eng. Chem. 48, 411 (1956). Benedict, W. S., Gailar, N., and Plyler, E. K., The rotation-vibration spectra of deuterated water vapor, J. Chem. Phys. 24, No. 6, 1139 (June 1956). Benedict, W. S., and Plyler, E. K., Interaction of stretching vibrations and inversion

in ammonia, J. Chem. Phys. 24, No. 4, 904 (April 1956). Bennett, J. A., The effect of an anodic (HAE) coating on the fatigue strength of magnesium alloy specimens, ASTM Bull. 55, 1015 (1955). Berger, M. J., An application of the Monte Carlo method to a problem in gamma-ray

diffusion, Symposium on Monte Carlo Methods (John Wiley & Sons, Inc., NewYork, N. Y., 1956). Berger, M. J., Angular distribution of multiple-scattered gamma radiation from a plane isotropic source, J. Appl. Phys. 26, No. 12, 1504 (Dec. 1955). Berger, M. J., and Doggett, J. A., Response function of Nal (Tl) scintillation counters, Rev. Sci. Instr. 27, No. 5 (May 1956). Birmingham, B. W., Some aspects of the large scale liquefaction of hydrogen, Proc.

Instr. Soc. Amer. 10, 2, Paper 55-2-1, 1-4 (Sept. 1955). Birnbaum, G., and Bussey, II. E., Amplitude, scale end spectrum of refractive index inhomogeneities in the first 125 meters of the atmosphere, Proc. IRE 43, 1412—

1418 (Oct. 1955). Blackburn, G. F., Freeze, P. D., and Caldwell, F. R., A study of thermistor materials

for use as temperature-sensing elements in the high-velocity exhaust gases of jet- type engines, Wright Air Development Center, Tech. Report 54-388, Suppl. 1 (1956). Blanch, G., and Rhodes, I., Mathematics. Table of characteristic values of Mathieu's

equation for large values of the parameter, J. Wash. Acad. Sci. 45, No. 6, 166 (1955). Blunt, R. F., Frederikse, H. P. R., and Hosier, W. R., Electrical and optical properties

of intermetallic compounds. I\ . Magnesium stannide, Phys. Rev. 100, No. 2, 663 (Oct. 1955). Bogue, R. H., Cement, Encyclopedia Americana (1955 Revision).

Booth, S. F., Government specifications, Plating 43, No. 4, 490-493 (April 1956). Branscomb, L. M., and Smith, S. J., Electron affinity of atomic oxygen, Phys. Rev.

98, No. 4, 1127 (1955). Branscomb, L. M., and Smith, S. J., Experimental cross section for photodetachment

of electrons from H- and D-, Phys. Rev. 98, No. 4, 1028 (1955). Branscomb, L. M., and Smith, S. J., Negative oxygen ions in the upper atmosphere:

The affinity and radiative attachment coefficient of atomic oxygen, Trans. Am.

Geophys. Union 36, 5, 755 (Oct. 1955). Brauer, G. M., and Sweeney, W. T., Effects of temperature and degree of polymerization on sorption of water by polymethyl methacrylate, Modern Plastics 32, No. 7 138 (1955). Brauer, G. M., and Burns, F. R., Sulfinic acid derivatives as accelerators in the polymerization of methvl methacrylate, J. Polymer Sci. 19, No. 92, 311-321 (Feb. 1956) . Brenner, A., and Wranglen, G., Cathode film studies by the drainage method, Sartrych

ur Svensk Kemish Tidskrift (Sweden) 67, 81 (1955)". Brenner, A., Electrodeposition of some of the less common metals from nonaqueous

media, Record of Chem. Progr. 16, No. 4, 241 (1955). Brenner, A., Progress in metal cleaning and finishing, Metal Progr. 68, No. 3, 113,

192, 194 (Sept. 1955). Brickwedde, F. G., Hudson, R. P., and Ambler, E., Crvogenics, Ann. Rev. Phys.

Chem. 6, 25 (1955). 146
Brickwedde, F. G., Temperatures in atomic explosions, Temperature, Its Measurement

and Control in Science and Industry 2, 395 (1955). Brode, W. R., Color and chemical constitution, Am. Scientist 43, No. 2, 259 (April 1955). Broida, H. P., Experimental temperature measurements in flames and hot gases, Temperature, Its Measurement and Control in Science and Industry 2, 265 (1955). Broida, H. P., and Carrington, T., Fluorescence and average lifetime of excited OH

(22+) in flames, J. Chem. Phys. 23, 2202 (1955). Broida, H. P., and Lutes, O. S., Abundance of free atoms in solid nitrogen condensed

at 4.2° K from a gas discharge, J. Chem. Phys. 24, No. 2, 484 (Feb. 1956).. Brown, B., Potassium iodide fast neutron detector, Rev. Sci. Instr. 26, 970 (Oct. 1955). Burdick, M. D., and Parker, H. S., The effect of particle size on the bulk density and

strength properties of uranium dioxide specimens, J. Am. Ceram. Soc. 39, No. 5 (May 1956). Burkhard, D. C, Hindered rotation in svmmetric-asymmetric molecules, Trans. Faraday Soc. 52, No. 397, Part 1 (Jan. 1956). Burnett, H. C, and Newton, C. J., Variations in preferred orientation and modulus

of elasticity in cold drawn music spring wire. Wire and Wire Products 30, No. 11 (Nov. 1955). Bussey, W. S., and Jensen, M. W., Weights and measures administration in the U. S. Supplement to "The Monthly Review" of the Institute of Weights and Measures

Administration (April 1956).

Cahill, W. F., and Levy, S., Computation of vibration modes and frequencies on SEAC, J. Aeronaut. Sci. 22, No. 12, 837 (Dec. 1955).

Cassell, J. M., A paper chromatographic analysis for collagen and collagen derivatives,

J. Am. Leather Chemists' Assoc. 51, 223 (May 1956). Chaix, B., and Henrici, P., On the design of two-dimensional nozzles by the method

of characteristics, J. Aeronaut. Sci. 22, 140-142 (1955). Clark, A. P., Cracking of reinforced concrete flexural members, J. Am. Concrete Inst. (April 1956). Cole, K. S., Antosiewicz, H. A., and Rabinowitz, P., Automatic computation of nerve

excitation, J. Soc. Indust. Appl. Math. 3, 153 (Sept 1955). Conrad, G. T., Jr., A proposed index of current noise for composition resistors, Proc. 1955 Electronic Components Symposium 118. Conrad, G. T., Jr., Noise measurements of composition resistors. I. The method

and equipment. II. Characteristics and comparison of resistors, IRE Trans, on Component Parts CP4, 61 (Nov. 1955). Cook, R. K., Waterhouse, R. V., Berendt, R. D., Edelman, S., and Thompson, M. C,

Jr., Measurement of correlation coefficients in reverberant sound fields, J. Acoust.

Soc. Am. 27, 6, 1072 (Nov. 1955). Cooter, I. L., and Harris, W. P., The Use of an AC bridge to measure core loss at high

induction, Commun. and Electronics, AIEE, No. 24, 252-256 (May 1956).

Corliss, E. L. R., Limitations on rapid signal analysis, J. Wash. Acad. Sci. 45, No. 11, 359 (Nov. 1955).

Corliss, E. L. R., and Koidan, W., Mechanical impedance of the forehead and mastoid,

J. Acoust. Soc. Am. 27, No. 6, 1164 (Nov. 1955). Cottony, H. V., High-gain antennas for VHF scatter propagation, IRE Trans, on

Communications Systems CS-4, No. 1, 17-27 (March 1956). Dahl, S., and Kaplan, A. M., Laboratory and field exposure studies of leather fungicides, J. Am. Leather Chemists' Assoc. 51, No. 3, 119-136 (March 1956). Dahl, S., Prevention of microbiological deterioration of leather, J. Am. Leather

Chemists' Assoc. 51, No. 3, 104-108 (March 1956). Davis, B. L., Components for mechanized production, Radio-Electronic Eng. 24, No. 3, 12 (March 1955). Davis, P., On a problem in the theory of mechanical quadratures, Pacific J. Math. 5, Suppl. 1, 669 (1955). Davis, P., and Rabinowitz, P., A multiple-purpose orthonormalizing code and its uses, J. Assoc. Computing Machinery 1, 4, 183 (Oct. 1954). Davis, P., and Rabinowitz, P., Numerical experiments in potential theory using orthonormal functions, J. Wash. Acad. Sci. 46, 12-17 (1956). Davis, P., and Rabinowitz, P., Some Monte Carlo experiments in computing multiple

integrals, Math. Tables and Other Aids to Computation 10, 1-7 (1956). Decker, G. E., and Mandel, J., Mooney viscometer cure characteristics of Hevea

rubber, ASTM Bull. No. 209, 47 (Oct. 1955). Defandorf, F. M., The electrical resistance of a live tree, AIEE Transactions Paper

No. 627 (1956). Defandorf, F. M., A tree from the viewpoint of lightning, J. Wash. Acad. Sci. 45, 11 (Nov. 1955). 147
Dejuren, J. A., and Chin, J., Manganese thermal neutron activation cross section, Phys. Rev. 99, No. 1, 191 (July 1955). Diamond, J. J., The flame photometric determination of manganese in cement, Anal. Chem. 28, 328 (March 1956). Dibeler, Y. H., Isotope analysis using dimethylmercury, Anal. Chem. 27, 1958 (Dec.

1955). Dibeler, Y

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. H., Mass spectrometry, Anal. Chem. 28, 610 (1956). Digges, T. G., Boron steels, presented at a Symposium on Production, Properties,

and Applications of Alloy and Special Steels, National Metallurgical Laboratory,

India (Feb. 1956). Dougherty, H. T., The propagation characteristics of the frequency band 152-162 Mc which is available for marine radio communications (Appendix F to report of Spec. Committee 19 of Radio Tech. Commission for Marine Services "Study of a

reliable short range radio telephone system") (Feb. 1956). Douglas, T. B., Epstein, L. F., Dever, J. L., and Howland, W. H., Lithium: heat

content from 0° to 900°, triple point and heat of fusion, and thermodynamic properties of the solid and liquid, J. Am. Chem. Soc. 77, 2144 (1955). Dressier, R. F., Comparison of theories and experiments for the hydraulic dam-break wave, Proc. Intern. Union Geodesy and Geophys. (Rome, Italy) 3, 319 (1954). Dunfee, B. L., An A-C bridge for the audio-frequency range, Commun. and Electronics, AIEE, No. 24, 123-128 (May 1956). Durfee, \Y. EL, Heat flow in a fluid with eddving flow, J. Aeronaut. Sci. (condensed

version) 23, 188-189 (Feb. 1956). Edelman, S., McKinney, J. S., and Marvin, R. S., Apparatus for the direct determination of the dynamic bulk modulus, J. Appl. Phys. 27, 425 (1956). Edelman, S., Jones, E.. and Smith, E. R., Some developments in vibration measure- ment, J. Acoust. Soc. Am. 27, 728 (1955). Elvey, C. T., and Roach, F. E., Aurora and airglow, Sci. Am. (Sept. 1955). Eubanks, A. G., and Moore, D. G., Effect of the oxygen content of the furnace atmosphere on the adherence of vitreous coatings to iron, J. Am. Ceram. Soc. 38, No. 7, 226-230 (July 1955). Fan, K., A comparison theorem for eigenvalues of normal matrices, Pac. J. Math. 5, Suppl. 2, 911-913 (1955). Fan, K., and Todd, J., A determinantal inequality, J. London Math. Soc. 30, (1955). Fan, K., and Glucksburg, I., Fully convex normed linear spaces, Proc. Nat. Acad.

Sci. 41, 947-953 (1955). Fan, K., Some inequalities concerning positive -definite Hermitian matrices, Proc. Cambridge Phil. Soc. 51, 414-421 (1955). Fan, K., and Hoffman, A. J., Some metric inequalities in the space of matrices, Proc. Am. Math. Soc. 6, No. 1, 111 (Feb. 1955). Fan, K., Taussky, O., and Todd, J., Discrete analogs of inequalities of Wirtinger, Monatsh. Mathematik (Yienna) Bd. 59/2 (1955). Fan, K., Taussky, O., and Todd, J., An algebraic proof of the isoperimetric inequality

for polygons, J. Wash. Acad. Sci. 45, No. 11, 334 (Nov. 1955). Feinstein, J., Information theory aspects of propagation through time-varving media,

J. Appl. Phys. 26, No. 2, 219 (Feb. 1955). Ferguson, R. E., and Broida, H. P., Atomic flames: spectra "temperatures" and

products, Fifth Symposium (International) on Combustion 86, (1955). Ferguson, R. E., On the origin of the electronically excited Cj radical in hydrocarbon

flames, J. Chem. Phys. 23, 2085 (Nov. 1955). Forman, R., Measurement and theoretical study of electrical conductivity and Hall

effect in oxide cathodes, Phys. Rev. 96, No. 6, 1479 (Dec. 1954). Forman, R., Properties of pore conductors, J. Appl. Phys. (Sept. 1955). Foster, B. E., Absorption by concrete of X-rays and gamma-rays, BuDocks Technical

Digest No. 56 (May 1955). Frankel, H. E., and Bennett, J. A., Understressing as a means of eliminating the damaging effect of fatigue stressing, ASTM Bull. 55, 891 (1955). Frederikse, H. P. R., and Mielczarek, E. V., Thermoelectric power of indium antimonide, Phys. Rev. 99, 1889 (1955). Frederikse, H. P. R., and Blunt, R. F., Photoeffects in intermetallic compounds,

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