Annual Report 1952

National Bureau

of Standards

U. S. Department of Commerce
1
UNITED STATES DEPARTMENT OF COMMERCE

Charles Sawyer, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. AsTiN, Director

Annual Report 1952

National Bureau

of Standards

Miscellaneous Publication 207

For sale by the Superintendent of Documents, U. S. Government Printing Office Washinfiton 2 5, D. C. - Price 30 cents

Contents

Pa£e General Review 1 Electricity Transfer instruments for a-c measurements 4, Computable air capacitor 5. 3

Optics and Metrology 5 Color standards for petroleum products 6, Dictionary of color names 6, Fundamental refractometry 7, Spectrophotometers 7, Intercomparison

of secondary standards 7, Standard angles 8, Optical measurements on the interferometer 8, Sensitometry of photographic papers 8, Coefficient of expansion of surveyors' tape 8, Thermal expansion 8. Heat and Power 9 Isotopic determination of water content 10, Properties of Gases 10, Highpressure pneumatics 11, Low temperature physics 12, Lubrication

studies 13, Cryogenic Engineering Laboratory, Boulder, Colorado 14, Jet engine fuels 14, Gas turbine combustion 15, Jet engine thermocouple 15. Atomic and Radiation Physics 15 Titanium dioxide rectifiers 17, Measurement of atomic masses 17, Solidstate physics 18, Alpha-helium scattering 19, Cobalt-60 source 20, Betatron program 20, Radiometry of fluorescence 20, Penetration of gamma rays 21, Photographic film dosimeter 21, Radiation data 21, Wavelengths for infrared standards 22, Complex spectra 23, Infrared spectroscopy 23. Chemistry 23

Structure in detergent solutions 24, Labeled sugars and sugar derivatives 24, Inorganic compounds 25, Dissociation constants 26, Chemical thermo- dynamic properties 26, Pure substances 26, Blood plasma substitutes 27. Mechanics 27

Sonic measurement of physical properties 28, Sound reverberation 28, Viscosity of gases 28, Hot-wire anemometers at high speeds 29, Fatigue

strength of structures 29, Stiffened skin for high-speed aircraft 30, Limit-load gage 31, Pressure drops in oxygen flow systems 32, Laboratory

centrifuges 32, Four-inch air gun 32, High-capacity load calibrating devices 32, Dam-brake problem 33, Density currents 33. Organic and Fibrous Materials 33 Deformation of elastomers 34, Structure and composition of collagen 34, Structure of cotton fibers 34, Structure of tooth enamel and dentin 35, Self-curing dental resins 35, Glass fiber reinforced plastics 36, Stiff"ness of paper 37, Burst test for fibrous sheet materials 37, Multiaxially

stretched plastic for aircraft canopies 38, Recovery of asbestos 38. Metallurgy 38

Corrosion 39, Deformation and failure of metals 40, structure of metals, 40 Metal fatigue tests 41. Ill
10 Mineral Products. . , , , , Refractory concretes 42, Constitution of glass 43, Ceramic dielectrics 43, Ceramics for atomic energy 43, Ceramic coatings for electrical uses 44, Adherence of Porcelain Enamels 45, Thermochemistry of mineral products 45, Cement 46.

1 1 . Building Technology

Thermal conductivity 47, Resistance of floor coverings 48, Cellular concrete

48, Protective coatings for concrete masonry 49, Window air-conditioning

units 49, Radiant glass heating panels 49.

12. Applied Mathematics

Numerical analysis 50, Statistical engineering 51, Computation 52.

13. Electronics Adhesive-tape resistor 53, Miniaturization 54, Electronic failure prediction 55, Cuvette densitometer 55, Oil film thickness indicators 55, Steam

turbine rotor position indicator 56, Vibration calibrator 56, Noble gas clean- up in electron tubes 57.

14. Radio Propagation

Radio astronomy 59, Ionospheric winds 60, Low frequency ionosphere

recorders 60, Radio navigation 61, Modulation studies 61, VHP propagation research 62, Terrain effects on VHF propagation 62, Power

standards 63, Impedance measurements and standards 63, Radio inter- ference and noise measurement 63, Atomic standards of frequency and

time 63.

15. Automatic Electronic Computers; Information Processing

SEAC 64, SWAC 65, New computers 65, Technical Services 66, Information storage 67.

16. Basic Instrumentation

Electron interferometer 68, Noise-free instrument cable 69, Magnetostriction magnetometer 69, Pulsed-voltage photomultiplier 69, Mutual

inductance transducer 70. 17. Calibration, Testing, and Standard Samples

Electricity 71, Optics and Metrology 72, Heat and Power 72, Atomic and

Radiation Physics 73, Chemistry 73, Mechanics 74, Organic and Fibrous

Materials 75, Metallurgy 75, Mineral Products 75, Building Technology 76, Radio Propagation 76, Weights and Measures 76.

18. Cooperative and Advisory Activities Federal specifications 77, Mechanical and electrical equipment 77, Rubber 78, Fungus proofing of leather 78, Mineral products 79, Building

technology 79, Mathematics 80, Radio propagation 80. National Cooperation

Weights and measures 81, Scientific and technical groups 82, Color

science 83, Research associate program 83. International Cooperation

International intercomparison of standards 84, Screw threads 85, Inter- national meetings 85, International relations 85. Publications

19. List of Scientific and Technical Divisions and Sections IV
I 1 . General Review

I During the last year, a total of 630 unclassified projects were conducted

the National Bureau of Standards. The fields represented by these

bjects included the physical sciences and engineering. Most of the

jireau's effort occurred in physics, mathematics, chemistry, metallurgy,

id engineering (electronic, electrical, mechanical, ceramic, chemical, and

j-uctural engineering). A considerable amount of work was done of

Irect interest to the medical, biological, and dental sciences; these activities bre concerned with physical problems : radiation measurement and probtion, X-rays, physical and chemical properties of blood plasma substitutes,

|.d various instruments.

! Within the physical sciences, the Bureau was engaged in basic and applied

search, development, calibration and testing, and a variety of scientific

irvices. Subsequent sections of this report present representative aspects

i this work. As in recent years, however, the bulk of the Bureau's effort

lis been directed to research and development for defense. The major

I ograms in this area have been concerned with advanced electronic j'dnance (including proximity fuzes) and guided missiles as well as atomic

f lergy. These programs were sponsored by various agencies of the Depart1 ent of Defense and by the Atomic Energy Commission. The details such programs are necessarily classified. "Most of the Bureau's work was conducted in its Washington, D. C,

boratories. However, a growing amount of activity characterized the

iterations of the other three principal laboratories—at Corona and Los

ngeles, California, and at Boulder, Colorado. The NBS Institute for umerical Analysis, located on the campus of the University of California,

OS Angeles, continued its well-established program in mathematical re- ^arch (particularly numerical analysis), computational services, and

ectronic computer machine development and operation. The Corona

aboratories, acquired during the preceding year from the Navy and suitDly equipped, were in full operation with a staff totaling some 400 by the

id of the year. The principal interests of this laboratory were missile

jrojects of interest to the Navy and ordnance work of interest to the Army,

long with work in electronics (e. g., automatic computers) and optics

'i. g., infrared spectroscopy) . At Boulder, a major cryogenic engineering

xility was constructed for the Bureau by the Atomic Energy Commission.

' he installation was in full operation by the middle of the year. Meanlihile, a contract had been let for a major radio laboratory, to be erected

!:i the Bureau's Boulder site and scheduled for completion by the spring of m.
Typical activities during the year included the following: Thin, h: strength skin for high-speed aircraft was developed. The performanc

very large orifice meters was studied. A new titanium dioxide recti was developed which has promising properties. A new method was devi for sorting out atoms of unequal masses and accurately determining

tremely small differences in their atomic masses. A semi-portable rac active cobalt source was developed for checking radiation instruments the field. Various radioactive sugars and sugar derivatives were develop The properties of blood plasma substitutes were studied—particularly

critical molecular weight. The properties of self-curing dental resins w

mvestigated. Progress was made in the electrodeposition of aluminum i molybdenum. Improved ceramic dielectrics, important in electronics, w

developed. The physical and structural properties of cellular concr were studied. Methods of solving large sets of algebraic equations w

studied. Studies of advanced, automatic electronic computers were und^ way. The National Bureau of Standards Eastern Automatic Gompu

(SEAC) was in operation 24 hours per day, 7 days per week, throughc

the year on important mathematical and scientific problems. The Burea

other computer (SWAG), after undergoing a test'and proving-in period now operating on a one-shift basis. As a result of the rapid expansion of the radio frequency spectrum durJ' the last war, considerable effort has been placed on exploring the nati of radio waves at the higher frequencies, important for defense comn

nications and for such civilian applications as television. Regular servic

like the broadcast of radio frequency standards by the Bureau's static WWV (Maryland) and WWVH (Hawaii) and the issuance of monti

radio propagation predictions (3 months in advance) , have been continue

A North Pacific Radio Warning Service was established during the ye for the Arctic regions; operating 24 hours per day, 7 days per week, t service is necessary for reliability of radio communications in those regioi

Extensive studies of the properties of radio waves between 94 and l,Oi megacycles have been conducted at the Bureau's Cheyenne Mountain J

tion. A new phenomenon of radio propagation by the ionosphere at tl higher frequencies has been discovered and is being intensively studid Reflections from the moon were used to send a radio telegraph message.

A number of advances were made in the field of basic standards

science. Last year was the first full year in which the new NBS atom

standard of length was available to industry and other laboratories: mercury- 198 lamps were distributed. Wavelengths were determined

provide infrared standards, hitherto unavailable, important in analyzir^

compounds, production control, and detection. Colorimetric specificatioi for a set of color standards for judging petroleum products were prepare

to replace the current obsolete standards. Considerable work was done o the standardization of safety colors. The calibration of a 24-sided polygoi

for calibrating in turn master angle blocks of industry, was completed.

2
cri

pne of the important services of the Bureau to business, industry, and

jk^ate laboratories is the comparison of working standards with the national

(;yjpdards of measurement. More than 56,000 calibrations were performed

the Bureau. Typical of this activity were the following calibrations: 388

itic calibration devices (proving rings, aircraft weighing cells, Amsler

as, etc.) , 743 water current meters, 474 timepieces, 8540 standard weights,

|)0 flasks, and 2500 hydrometers. Calibration and testing for the Goviiment included the calibration of more than 20,000 clinical thermometers

Impled from 200,000 purchased) and the sample-testing of 15,800,000

rels of cement and 6,700,000 light bulbs. Approximately 30,000 standi samples (substances of known composition) were distributed to industry

d private laboratories during the year while the Government itself used

Dut 4000 units. jThe total funds appropriated by Congress for the Bureau's basic program

Ire 8.6 millions, consisting of 6.9 million for the technical activity and 1.7

lllions for administration, shops, plant maintenance and laboratory renotions, etc. Several organizational changes were made in the Bureau's technical divi- m structure during the last year (see the end of this report for a list of

/isions and sections) . An Associate Director was appointed to coordinate

e Bureau's calibration and testing activities. The growth of the ordnance

/jogram made it advisable to form three new divisions in place of the

[jigle previous division, and an Associate Director was appointed for this

jjtivity. A cryogenic engineering section, part of the Heat and Power Divi-

\m, was established at Boulder, and a section concerned with the structure

- high polymers was established in the Organic and Fibrous Materials

jivision. The rest of this report presents some of the activities of an unclassified

(Lture of the Bureau during the year. Sections 2 through 16 contain brief

,ports of representative projects in research and development. Section 17

iiimmarizes the Bureau's work in calibration, testing, and the preparation

;id issuance of standard samples. The cooperative and advisory activities the Bureau—within the Government, nationally, and internationally

e outlined in section 18. The list of scientific and technical divisions and

ctions, noted above, appears in section 19.

i 2. Electricity

The work in electricity is primarily concerned with the development and

jiprovement of standards and methods of electrical measurement, and

ndies of properties of materials that are important in electricity and magitism. The Electricity Division is also responsible for the dissemination of

le improved standards to scientific and industrial laboratories. The quanties measured in the course of this work include electrical resistance, cururnt, coltage, inductance, capacitance, energy and power. During 1952

!
I.

Left: standardization of an a-c voltmeter in the electrical instruments laborat( . Right: thermal converters and voltmeter elements used at the National Bureat h Standards for testing ammeters and voltmeters at audio frequencies (p. 4). considerable manpower was diverted to projects requested by the Dep£

ment of Defense. These included the determination of the electrical magnetic properties of materials under extreme or unusual conditions

quired for the development of new military devices. Transfer Instruments for A-C Measurements

Higher audio frequencies have been steadily adopted for use in aircrj in induction furnaces and heating, and in certain important electro:': developments. One phase of a program to increase the range and accun

of electrical measurements at these audio frequencies was completed

1952. Improved transfer thermal converters and associated equipment n

will enable the Bureau to meet rapidly growing demands for the accur; standardization of ammeters and voltmeters at frequencies higher th

previously.

Thermal converters have long been used in thermocouple instruments |j moderate accuracy. The Bureau's study shows that converters which mi

special requirements can be used for a-c measurements by transfer methc.

with an accuracy approaching 0.01 percent. In the transfer method, ; instrument is calibrated with direct current, in terms of the fundamental ci standards, immediately after each measurement with alternating currei Instruments may be designed for such service, as were these thermal transf instruments, to obtain increased precision of reading with little dependen

on long-time stability and other secondary characteristics. Of fundament"

importance, however, is the ac-dc difference or transfer accuracy. Caref

experimental studies of different types and ranges of available thermal co

verters and a detailed intercomparison of converters with other types

transfer instruments disclosed a number of factors which may limit tl transfer accuracy of converters at audio frequencies. Theoretical evalu

tions of these factors were correlated with actual measurements so that

is now feasible to specify design characteristics needed for the require accuracy. 4
tape-measuring tunnel where improved method for determining coefficients

j inear thermal expansion of geodetic tapes is used (p. 8). Insert: a twentyjr-sided polygon was constructed and calibrated (p. 8). imputable Air Capacitor

iGood progress has been made on the construction of an air capacitor of

'||.h design that its capacitance in electrostatic units can be computed with

high accuracy from measurements of its physical dimensions. Supplentary capacitors have been built for stepping up values based on these 'nputations by a factor of several hundred. These can then be compared

j|;h values obtained in electromagnetic units by measurements based on our

^ndards of resistance and frequency. This work, when completed, will ve two purposes : first, a determination of the ratio of the electrostatic to electromagnetic units which should be a measure of the velocity of light

^ i, second, assuming that the velocity of electromagnetic waves is the

ine at these low frequencies as at the frequency of light waves, an inde- ndent method for measuring the unit of electrical resistance in absolute

I 3. Optics and Metrology

The activities of the Optics and Metrology Division include photometry

i colorimetry, refractometry, optical and photographic technology, and

; applications of metrology which are most dependent upon optical methis. Calibration of line standards, interferometric measurements of length,

'd measurements of the coefficient of linear expansion are part of this

rk. Noteworthy work of the division included an international com-

!
parison of photometric standards which showed the measurements i by the NBS to be gratifyingly near the mean of the resuhs of five particip

national laboratories. The division established color standards for p

leum products and a dictionary of color names. Initiation of a prograi

measuring the index of refraction of optical glass and crystals over the e spectral range within which they are transparent, important applica

of an interferometer with optical planes 10 inches in diameter, a new

cedure of sensitometry applicable to photographic papers, and a new

more convenient method for measuring the coefficient of expansion of veyors' tapes were also part of the division's work.

Color Standards for Petroleum Products

Crude oil is black and nearly opaque; as it is refined the color cha

through reddish black, dark reddish brown, orange, and yellow to cr clear. The degree of refinement can thus be judged by color, and ( measurement plays an important part in the purchase and sale of pan

refined oils. For more than 20 years the petroleum industry has depei

upon a set of 1 2 glass color standards from abroad, which imperfectly d

cated by nonuniform steps this range of oil colors. At the request o:; American Society for Testing Materials, the division developed colorim

specifications for a set of color standards adjusted precisely to the ave

color range of petroleum products, covering this range in 16 uniform s Also determined were the thicknesses of glass components of Amei

manufacture required in combination to meet these colorimetic specificat

Dictionary of Color Names

Great dependence is placed on color names by commerce and indu

These names run into the thousands and have their origins in diverse and technologies. Some names identify wide ranges of colors, others intended to pin-point a single color. Existing dictionaries of color n

defining each by an actual color swatch have limited usefulness in indi because they fail to show the extent of the color range indicated by the n; By making use of a method of designating colors by 21 common ger terms (red, yellow, green, light, dark, and so on) developed at the Bu

in 1939, this defect has been overcome. All possible colors are divided

267 groups, each identified by combinations (such as dark red or j green) of these generic terms. A dictionary, prepared at the Bureau

the cooperation of the Inter-Society Color Council, lists alphabetically al 10,000 color names. It coordinates all the published information on c names used by American science and industry including mass-market nai the color names used in textiles and plastics, those used by Federal ager

in the purchase of paint, those used in interior decoration, those used for colors of rocks and soils, and those used in biology, botany, horticulture,

philately. Translations from one color language to another (such as Gri

Viridis (biology) =Serpentine (fashion) =Mint Green (mass market

t

6
\rt green (ISCC-NBS)) are thus easy, and confusion and misunder1 iding may be avoided.

] idamental Refractometry

^ 'echniques were developed for the measurement of indices of refraction

^ :rategically important optical media over their entire useful ranges includ-

^ the near ultraviolet, visible, and infrared regions of the spectrum. The

':hods for the different regions are now as nearly the same as is feasible sidering the differences in the radiations and the different expedients

^ t must be employed for their isolation and detection. In particular, the

ily sensitive method of minimum deviation can now be employed, and

j-consistent data can be obtained for adjustments by dispersion equations,

indices of reflection of optical glass, lithium fluoride, potassium bromide,

1^ cesium bromide have been determined and published either in final

"jentative form. The refractive uniformity of samples of annealed borofate optical glass was precisely determined by interferometric methods

!l found to be as good as ±1 x 10~® regardless of the annealing temture employed within the limits 490° to 530° C. |ctrophotometers

[thousands of spectrophotometers are now in daily use in industrial and

^'iernmental laboratories as research and analytical tools in physics,

'mistry, engineering, and technology. For many years the National eau of Standards has prepared and issued permanent glass standards

various types for use in checking the calibration of spectrophotometers

'he visible spectrum. Such glass standards are unsuitable in type for

I in the ultraviolet, however, and are not permanent in that region,

kfter several years of work the Bureau has completed measurements on

Vlkaline solution of potassium chromate, which will serve as a spectroitometric standard in the ultraviolet. The solution may be readily

spared from the specified composition. It will enable the users of ictrophotometers in the ultraviolet region to check the reliability of the rument's photometric scale and to detect important errors resulting n wavelength inaccuracies, stray light, or excessive slit widths.

3rcomparison of Secondary Standards

'orty-five sets of intercomparisons of a group of ten of the Bureau's

er bars were made, each bar being compared with all the others. The

irvations were reduced by the method of least squares, and the probable

Dr obtained from the comparisons was ±0.03 micron. Computations

"e made using only 25 and then 30 sets in the reduction, and it was found

t the computed lengths of the standards varied by a maximum of 0.04 ron from those lengths computed from 45 sets of direct comparisons.

LS indicates that a lesser number of direct observations need be taken

I that a high degree of accuracy can still be maintained.
Standard Angles |- The calibration of a 24-sided polygon constructed at the National Bn |v) of Standards has been completed. The polygon has been used to deterr ;3 the values of the angles of master angle blocks of 15°, 30°, and ^ Inasmuch as each angle block can be compared with a number or a :t the 24 angular intervals on the polygon corresponding to the angle of i block, it has been possible to determine the angles of these master bL i with probable error not greater than 0.1 second.

| j Optical Measurements on the Interferometer

A large interferometer which transmits a beam of light 10 incheli diameter has been completed and used for a variety of tasks. The ? chanical design is such that this forms a universal instrument of which ;j) components can be combined to form any one of several well-known t^!r of interferometer. The instrument has proved an indispensable tool r the investigation of large disks of optical glass. It has been used to mea5%

the variation of index of refraction within such a disk along a diamem

This interferometer has also been used to test large photographic objectM

for airplane cameras. In connection with the testing of these large

mentSj the Bureau is now equipped to grind and polish disks as largf li^ 30 inches in diameter.

Sensitometry of Photographic Papers

jj A new method of sensitometry, termed the bar-gamma method,

application to photographic papers has been devised. The method p vides a simple, rapid means for evaluating papers with respect to \

exposure scale and contrast (bar-gamma), and yields results which

reproducible with high precision. An ASA standard dealing with ; sensitometry of photographic papers based on this method has recently bi adopted. A proposed Federal Specification for photographic papers 2, cloths, embodying this method of sensitometry, is now being prepared. \, Coefficient of Expansion of Surveyors' Tapes i A new method was developed for determining the coefficients of lini' thermal expansion of geodetic tapes. Coefficients of expansion of 50-me

tapes were derived from measurements of the electric resistance ver^ ambient temperature (temperatures from 0° to 50° C) and of the lin* expansion versus electric resistance (on heating the tapes to various td' peratures by passing direct current through the tapes) . The new meth

promises to be more rapid than the old, which required observers to w(

in uncomfortably hot ambient temperatures. \\ Thermal Expansion

A long series of measurements of the coefficients of thermal expansi', of selected aluminum alloys was completed and a number of papers pt

lished. Part of the work consisted of investigating the relationship betwe

chemical composition and thermal expansion.

^'

8
" new type of interferometer (p. 8) used to measure the variation of index of

t i raction in large glass disks. I^5 4. Heat and Power

I

( To provide a fundamental basis for precise measurements of heat and

[wer, the Bureau has established and maintains a scale of temperature

|er most of the range from the lowest obtainable to the highest temperaFfres of incandescent bodies and flames. NBS-calibrated platinum re-

'[ftance thermometers, thermocouples, and optical pyrometers are used as

' '|,ndards in industrial and university research laboratories. This calibraitj'n service represents the only effective way of ensuring that the various

'l^ooratories are employing the same temperature scale.

'l The work includes the determination of quantities of heat by calorimetry

I temperature regions extending over a large part of the scale and the brmal properties of solids, liquids, and gases (measured over a wide range

i temperatures and pressure) —e. g., heat capacity, heats of vaporization

lid sublimation, vapor pressure, and thermal conductivity. Coordinate

Ij^oretical programs relate the thermal properties to molecular structure

,j d involve the calculation and compilation of tables of thermal properties

I the basis of NBS and other data. IFrom these fields of research the work branches into engineering applicalins: automotive and aircraft engines and accessories, high pressure pneu-

|atics, and cryogenic engineering. Basic lubrication studies are conducted

I the characteristics of fluids and bearings for use in mechanical equipment.

,ie Bureau is also responsible for determining and maintaining standards

1 viscosity and for certifying the viscosities of fluids used for calibrating

|cometers. It maintains the primary standards for the determination of

2 octane numbers of automotive and aviation fuels. Research is con-9
ducted to increase the accuracy of these standards and to develop

proved measuring instruments and apparatus.

Isotopic Determination of Water Content

A method which uses heavy water to determine the total water con

of biological tissues and other materials was developed. This work

part of a program of basic instrumentation sponsored by the Departn

of Defense and the Atomic Energ)' Commission. Based on a spectroscc

measurement of the ratio of ordinary to heavy water in a solution contair the sample^ the new method can be applied to a large number of sam

with rapidity and convenience. Recent experiments at 'the Bureau h shown that it saves considerable time in determining the water of hydrai

of inorganic crystals and proteins, the extent of hydration of the hur

body, and the water content of bacterial cells. Other applications to wh

the technique has been applied include studies of water exchange in re and of water transport through human capillaries, determination of moist; in the atmosphere, and the identification of unknown organic molecules' A known amount of the material to be analyzed is dissolved in a mixt

of deuterium oxide (heavy water) and hydrogen oxide, and the result' change in the ratio of deuterium oxide to hydrogen oxide is then determii,

spectroscopically. From the difference in this ratio before and after addit

of the sample, the water content of the sample, which is assumed to cont i no deuterium oxide, is computed. The analysis takes advantage of wavelength separation of the emission lines of hydrogen and deuterium (

;

to the isotopic shift. By means of a high-frequency electrodeless dischai water vapor from the sample is dissociated into H and OH and into D c OD. The ratio of excited hydrogen to deuterium, which is a function

the ratio of hydrogen oxide to deuterium oxide, is then determined by me

uring the relative intensities of the H line (4861.3 A) and the D 1 (4860A).

Properties of Gases \ The systematic study and preparation of tables of thermal properties a group of wind tunnel gases, fluorine compounds and, more recently, deu

rium compounds has been undertaken. The compilation and calculati of tables of thermodynamic and transport properties of wind tunnel and i engine gases including oxygen, nitrogen, hydrogen, carbon dioxide, carbl monoxide, argon, and steam were completed. In all, 100 tables were cak

lated giving the compressibility, density, heat capacity, entropy, enthalj

specific heat ratio, sound velocity, viscosity, thermal conductivity, and vap

pressure from low temperatures and pressures to 3,000° K and 100 atm(

pheres. Particular attention was directed to the properties of air; cha

and tables were issued extending the known properties to pressures of 5,0

pounds per square inch. Reports were issued on a comprehensive investigation of thermodynan

and related properties of fluorine and deuterium compounds. Heat capa

10
:,lal water content of biological tissues and other materials is determined by an

iopic method (p. 10). A discharge tube (left) is scanned by a monochromator

ff[;ht center), and the photoelectric recorder (extreme right) indicates the change

„jhe ratio of ordinary to heavy water (deuterium).

J

j entropy, enthalpy, and free energy functions of ten simple fluorine .nponds were calculated and reported from 100 to 5,000° K. Theoical analyses of the molecular data of several groups of related fluorineitaining molecules are in progress. This work is complementary to an

)erimental program on the same class of materials. The measurements

lude determinations of the heat capacities of such substances as the

fion polymer, the refrigerants Freon-12 and perfluoropropane, and three

; er important fluorine compounds. The ultimate objective of the experi-

' ntal and theoretical programs is to obtain a complete ensemble of thermal,

^'•lecular, and related properties of all simple and some of the more comX compounds. The accumulation of such data should facilitate the solu- n of many problems arising from diverse uses of fluorine-containing mateIs. These materials exhibit an extraordinary range of properties, e. g.,

•y include some of the most stable as well as the most reactive and corrosive

,all known chemicals.

^gh-Pressure Pneumatics

,\ pneumatics laboratory has been established with the cooperation of the

. vy Bureau of Aeronautics to further the development and technical evalu-

. Dn of pneumatic systems and equipment. The need for greater economy

"utilization of weight and space in aircraft has led to new developments

the pneumatics field. For example, although compressed air has been

yd for years, the trend is toward much higher storage and working pres-

•es as well as greater actuation speeds. Systems are now being designed

pressures of 3,000 pounds per square inch and actuation speeds of a few

lliseconds. Preliminary calculations indicate that storage pressures of

'00 psi are justified and that perhaps even higher pressures may yield

"^ther savings in weight and space, but with diminishing returns.
The pneumatics laboratory has placed in operation high-pressure, h t capacity facilities and developed instrumentation to study the pneum, # of high-pressure, short duration, transient flow. It is now engaged in i technical evaluation of airborne pneumatic systems and individual c

j | ponents such as actuators, pressure reducers, special purpose valves, sto I i reservoirs, and other related equipment. The laboratory is also conduc i parallel theoretical and experimental investigations on the phv ja phenomena associated with the thermodynamics and mechanics of f flow. Low-Temperature Physics

During the past year the National Bureau of Standards low tempera

laboratory expanded its research program to include the investigatioi

magnetic properties of paramagnetic salts. Research on superconducti

and properties of liquid helium was continued. Facilities were prep^

for the production and storage of liquid helium in large quantities and

the attainment of extremely low temperatures by means of adiabatic

magnetization. The liquefier designed at the NBS produces heliurr the rate of 15 liters per hour. An improved transfer and storage met

permits the storage of liquid helium in large dewar vessels for long pen

of time; the total available storage capacity is about 200 liters. The attainment and measurement of temperatures of the order of a thousandths of a degree Kelvin are now possible at the National Bur

of Standards through the installation of a large electromagnet, a precis

mutual inductance bridge, and associated apparatus. This program p vides a method for extending the NBS temperature scale down to the ra of few hundredths or thousandths of a degree on the absolute scale. 1 i equipment, utilizing the cooling eff'ect of demagnetization, was designee

the Bureau. In the field of superconductivity, investigation of the isotope eff; continued and developed along several lines. The discovery of t: phenomenon in 1950 demonstrated a connection between the isotopic o

stitution of a superconductor and the superconducting transition te perature. It was shown that the heavier isotopes of a given elemi become superconducting at lower temperatures than the lighter ones. T

knowledge has led to a better understanding of the nature of the sup ^ conducting state and has stimulated theoretical physicists to suggest n and promising theories of superconductivity. Special apparatus and p

cise techniques developed for this work were used to complete a study

thallium isotopes. The results have been in general agreement with th( obtained earlier with tin isotopes.

The investigation, in collaboration with the Argonne National Lai

ratory, of thermal wave propagation in a 4-percent mixture of the rs isotope helium 3 in ordinary liquid helium 4 contributed new results. T

measurements, carried out by means of the NBS-developed them

12
tijjit: dead weight gage (left center) used to calibrate pressure gages (on panel)

1 1 the new pneumatics laboratory (p. 11). Right: air compressed to 3,000

^^Unds per square inch is furnished by this compressor (p. 11).

, iyleigh disk method, showed wave velocity of the thermal wave to be

j,lreased by the presence of the heHum 3 impurity, down to the lowest

fjjinperature of 0.9° K. This result is of fundamental significance to the

e played by statistics as absolute zero is approached. The disk obsertions also provided measurements of the kinetic energy density of thermal

. opagation, showing a marked reduction due to presence of helium 3^ as

I edicted. The torque determinations with the disk also provided the first

||3cific heat measurements for the mixture, in good agreement with the

Teoretical values.

ifbrication Studies

jln many applications the oil fed to a journal bearing serves a dual pur-

>tse. While its primary function is to act as a lubricant in the development

a load-carrying film, it also is called upon to carry away the heat genated in the bearing. As a consequence, the rate of flow of oil through

bearing is an important consideration in bearing design and operation,

xently a simplified method of analysis for the rate of oil flow in plain

Pamal bearings was developed from data obtained on the NBS four-bearing

fction machine.

^The problem of lubricating bearings and the reduction gears in turboflop engines operating at extremes of temperature is of considerable interest the military services. To determine the properties of these lubricants,

^5 Navy Bureau of Aeronautics sponsored a project to investigate the use

the Modified SAE and the McKee Extreme Pressure Lubricants Testing

achines for determining the antiwear and the load-carrying properties

turbo-prop lubricants. These machines use two contacting cylindrical

;t cups which are rotated under load at diflferent speeds to give combined

llling and rubbing action typical of gear teeth. Methods were developed

fpich show promise for controlling the anti-wear and load-carrying propities of turbo-prop lubricants. Thirty-five lubricants were tested. With

228268—53 2 X3
regard to low viscosity at low temperature, high load-carr\dng capacity^ v wear, and good stability at high temperatures, some of the additive-i j synthetic oils are superior to mineral oils and appear to be suitable for ; as turbo-prop lubricants. Cryogenic Engineering Laboratory, Boulder, Colorado

This year saw the completion of the construction and putting into regi

operation of the world's largest liquid hydrogen plant and cr^^ogenic lab( lory on the Bureau's site in Boulder. The capacity of the plant is 320 li of liquid hydrogen per hour. The hydrogen liquefiers and the purifiers the hydrogen are in duplicate so that the plant can be operated conti ously without shutdowns. The hydrogen liquefiers and purifiers were

signed and constructed by the Bureau. The liquid hydrogen plant is s plied with liquid nitrogen from two 10,000-liter storage containers wh- are filled by two liquid nitrogen generators each producing 250 liters i hour.

The liquid hydrogen and liquid nitrogen plants are housed in one build

having a floor area of 14,000 square feet. There is also a separate laborat building with 20,000 square feet of floor space. Both buildings are provi( i with many safety and anti-explosion features to minimize the hazards

working with liquid hydrogen in large quantities. There is a staflf of manning the plant and laborator}^ buildings.

The Cr)^ogenic Engineering Section was organized to operate the liq

hydrogen and nitrogen plants and to conduct engineering research and

velopment to make the handling of liquid hydrogen in large quantities s, and more convenient. This new section will also determine engineer

data for cr\^ogenic equipment.

Jet Engine Fuels In a reciprocating engine, the power developed is dependent mainly

the compression ratio, but raising the compression ratio tends to incre; the knocking tendency of the fuel; high-octane fuels have a lower tender

to knock than ordinar\' fuels; hence the compression ratio of the engi

may be raised and the power increased. However, for jet fuels there is single critical property comparable to octane number. These fuels shoi: burn fast, leaving a minimum of smoke, and should have a high heat

combustion in relation to their weight.

A project is nearing completion in which several hydrocarbons havi; different structures were synthesized and studied to determine which ty of compound satisfied the requirements of a jet fuel to the greatest extei In complementary studies the compounds prepared were used in the Cle\

land Laboratory of the National Advisory Committee for Aeronautics in study of the mechanism of flame propagation. Precise physical constar were measured at NBS; in several cases the unusual structure of tl compound warranted measurement of its thermodynamic properties.

14
V|\lniost every conceivable type of aliphatic hydrocarbon has been reprej Jited in these syntheses. These compounds were purified by fractionation pcedures which resulted in products of very high purity. Some of the iipounds were unknown prior to this work, and several new methods and

hniques in organic syntheses were developed.

j^^, 5 Turbine Combustion

Xft Problems of gas flow, heat release, and mixing in combustion chambers

Ejijve been investigated analytically and experimentally for the purpose of

; Jtaining basic data applicable in designing gas turbine burners. These

Xi-dics are based on an idealized or equivalent burner producing the same

result as an engine combustor. Mechanical means were used to con-

; J»I the ratio of the air taking part in the burning to that which is later

; xed with the flame gas. Observed values of pressure drop in the burner,

5 efficiency of combustion, and the rate of mixing of flame gas and

:ondary air were found to agree reasonably well with values predicted

the analytical treatment, which appears to afford a sound basis for

(.^lubustor design.

M: Engine Thermocouple

'A thermocouple designed for flight service in jet engines in which the

,'inperatures of the gases are above the range of conventional thermocouples

|js been developed. The new unit, useful to 3,700° F, has thermoelements

\%de of irridium and an alloy of irridium and rhodium. The insulating

^ Aterial is thoria, and the uncooled supporting tube is molybdenum, profited from oxidation by a coating of molybdenum disilicide. The thermo-

'f'ments retain their mechanical strength and stiffness at the highest

llierating temperature and do not bend even when immersed in hot gas cams moving at the velocity of sound. Their principal disadvantage

n in their relatively low thermoelectric power, but it is large enough to measured accurately by modern potentiometer indicators or recorders.

lie thoria insulation maintains its high electrical resistance, even in the nnperature range in which the more commonly used porcelains become

rnducting. The silicide coated protecting tubes have a limited life at 00° F, but this life is considerably in excess of the duration of flight the applications for which the unit was designed.

i 5. Atomic and Radiation Physics

results of atomic and nuclear research are of importance to research

j')oratories, medical institutions^ industry, the military services, and other

')vernment agencies. The program of the Atomic and Radiation Physics

vision is primarily concerned with studies of (a) fundamental particles :h as atoms, nuclei, neutrons, and electrons (beta-rays), (b) properties

radiations, particularly gamma- and X-rays and ultraviolet, visible and

'rared light, and (c) the interactions between such radiations and paroles. Emphasis is placed on the fundamental research and development

15
The NBS Cryogenic Engineering Laboratory, Boulder, Colorado, was comple

(p. 14). Top: nitrogen liquefier room. Bottom; hydrogen liquefier room. >

16
bssary to meet the ever-increasing demand in these branches of physics

jnew standards, more accurate values of atomic and nuclear constants,

iable data on the properties of high-energy radiations, new and improved

[hods of measurement, and the calibration of sources of radiation and

pstruments used for detecting these radiations.

iin example of the increased service which the Bureau has given to the

Imic Energy Commission, other Government agencies, and the public is

Ijnd in its calibration program on cobalt 60. As recently as 1949, radio- ve cobalt of mass number 60 was of interest to only a few (workers

laged in nuclear research. In July through December of that year, less

pi 1,000 millicuries of cobalt 60 were measured and certified by this

j-eau. From January through June 1952, over 250,000 millicuries were

bured, requests for an additional two million had to be rejected, and

^rly one million were awaiting test. In addition to the programs for ch the Bureau has primary responsibility, many investigations were

[ried out for the Atomic Energy Commission, the Department of Defense,

I other Government laboratories. Typical programs included the studies

«protection against radiation, the development of radiation detecting

ruments, research on semiconductors and solid state electronics, and

development of new techniques in electron physics and mass

btrometry.

ianium Dioxide Rectifiers

In major problem in the electrical industry is the conversion of alternatto direct current. This may be done in a number of ways ; where mod-

:e amounts of power are needed, such as in a radio or television set or in electroplating industry, the most convenient method uses a metal recti-

, At present, the most satisfactory devices of this nature use the element

rnium. There are, however, two practical difficulties with the use of nium : ( 1

) the rectifiers cannot operate satisfactorily at temperatures

ch above 100° C and (2) selenium is currently in acute short supply,

nvestigations of the semiconductor titanium dioxide led to the discovery

!i new unit that has considerable promise, particularly for high temperai operations. These new rectifiers are made by heating titanium metal

vater vapor at temperatures around 600° C. This treatment produces a

1, tightly adherent coat of semiconducting titanium dioxide on the nium-metal base. A second electrode is then electroplated on the oxide

?r. Laboratory tests on the electrical properties of these units show that

y have some advantages although they are at present not the equal of the nium rectifiers in some respects. In particular, their rectification is jte good at 150° C. The comparative simplicity of their preparation

gests that it may be possible to produce commercial units. asurement of Atomic Masses

\ new method has been devised for sorting out atoms of unequal masses

I accurately determining extremely small dififerences in their atomic

17
masses. This is accomplished by measuring the time-of-flight of par

passing through crossed electric and magnetic fields. The method

tively combines the principle of resonance, as utilized in a cyclotron fo acceleration of particles to high energies, with the conventional analyz a mass spectrometer for separating atomic masses. The resulting i; ment has distinct advantages over either a mass spectrometer or cycle!

because it surmounts several limitations which restrict the accuracy attain by using either method separately. The measurement of heavier m'

has in the past been especially difficult and severely limited in accur

the new method appears to be most effective for heavier masses andl demonstrated greater power to separate atoms of very slight mass-differ than any previous mass spectrometer.

The utmost precision in determining atomic masses is essential for ther development of atomic energy programs and for future researd nuclear theory. The importance of mass values arises from the basic e tion used in calculating the amount of energy released in a nuclear reac

or in checking theories of the internal structure of the nucleus. An in

tion of the degree of accuracy required in measuring these values ca . obtained by considering the uranium atom. An error or uncertain^,

only four parts per million in the value used for the mass of the uran

nucleus results in an uncertainty of one million electron-volts in the ca

lation of the energy- of a nuclear reaction involving uranium.

Solid State Physics

An important new method for studying inperfections in crystals • devised. Crystals are usually considered to be perfectly regular tb

dimensional arrays of atoms, but it has been realized within the last twe

years that a great many of the most important electrical and mechani"

properties of solids depend on the presence of irregularities, such as miss

atoms or atoms trapped in the wrong place in the ideal cr>-stal structure

^ Because of the great practical importance of the effects of these imperf

tions (e. g., in the sensitivity of photographic plates, electrical properties

transistors, chemical catalytic behavior, oxidation of metals, and fluoresce screens on television and radar tubes), there have been many efforts i devise methods for the accurate measurement of the numbers of th

defects. Although the presence of the defects could be clearly demc

strated, no method was found that could measure directly the number

defects or give a clear indication of the type of imperfection.

Work at the NBS led to the recognition that these imperfections shoi' influence the absorption of mechanical energy by the cr>-stal, and pi

liminary tests completed about a year ago showed that the effect could

observed. During the past year a new instrument that makes these measui

ments rapidly and precisely was devised and placed in operation. T

principle of the method is simple; the crystal, in the form of a bar mount' on nearly frictionless supports, is set in vibration and the time requin

18
• new method has been devised for sorting atoms of unequal masses (p. 17).

j^ae analyzer of the new mass spectrometer now under construction is partially

„ moved for inspection.

r the vibrations to die away is measured. From studies of the decay

I oscillation at various temperatures, it is possible to obtain considerable

. (formation about the number and properties of the lattice defects. Meascements thus far completed on a cr\-stal of rock salt have not only

/(vealed many expected features but much new detail that will require

'.•'itended theoretical study. This method of investigation promises to be- come a valuable approach to the study of crystal imperfections.

^^tlpha-Helium Scattering

Until quite recently heHum-ion beams were not available with the energy

.^^ssolution and intensity required for the study of the scattering of alpha

.jjarticles of different energies in helium. Work along these lines had to y done with natural radioactive alpha emitters and hence low intensity

jjnd poorly resolved beams. Recent developments in radio-frequency ion

jOurces have made it possible to obtain high intensity helium-ion beams

•om electrostatic generators. Such sources were recently installed in the

jvo generators of the Department of Terrestrial Magnetism, Carnegie Inl itution of Washington, and alpha-particle scattering was one of the first ^'roblems attacked in cooperation with that Institution. The energy region

-'om 200,000 to 3 million volts has now been covered. This investigation

^as bridged the unexplored gap in energy between the extremely low enrgies, where nuclear effects are negligible, and the energies where some

"f the older work with natural alpha emitters had been carried out in -ngland.

19
Coi5alt-60 Source

Radiation instruments for the detection of gamma rays are now in i duction for use by the military services and in civil defense. The accu: calibration of these instruments is essential, and it must be possible to ch the meters under field conditions. The most direct means for accomplisl:

this is through the use of a compact source of radiation, and it has b

decided that radioactive cobalt will be satisfactory in this connection. Si the quantities of cobalt are large, serious problems of handling and j tection arise during its use. A semi-portable radioactive cobalt source C( bined with the accessory devices for the calibration of instruments has b

developed by the NBS. It contains a 9-curie cobalt slug (the quantity

radiation from such a slug is comparable to the largest radium sources u

for therapeutic purposes before the war) . Basic requirements of the eqr

ment included portability for handling under field conditions, suitabi for use on truck, shipboard, laboratory, or on the ground, adequate shieldi compliance with the ICC shipping and storage regulations, and minim

vveight and maximum ruggedness consistent with the above requiremei

Several prototypes have been constructed and put into use; the equipm

is now going into quantity production for the military services. Betatron Program

To keep pace with the new developments and the application of vt high-energy radiations to physics, medicine, and industry, the Natioi

Bureau of Standards has procured two electron accelerators for produci

X-rays in the multimillion-volt region. A 50-million volt betatron anc

180-million volt synchrotron are now installed in a specially construct building designed for obtaining experimental results under a wide vari( of working conditions. X-rays from the betatron have been utilized research since January 1, 1952, and faciUties for the removal of the electr beam from this machine are now in the testing stage. Magnetic fie measurements and component testing of the synchrotron are virtually coi pleted, and X-rays up to 180 million electron volts should be available f research during the coming year. The applications of multimillion-volt accelerators in the fields of medic

therapy, industrial radiography, and nuclear physics research are increasii rapidly. These applications of high-energy radiations have made it nece' sary for the Bureau to undertake a broad program of measurement ar instrumentation and the determination of safety and operational requir

ments needed by laboratories and industrial organizations.

0

Radiometry of Fluorescence

The extensive adoption of fluorescent lighting during the last 15 yea

for household, recreational, commercial, and industrial uses has arouse

interest in its relationship to colors, e. g., in paints, fabrics, chemical rea( tions, and even the appearance of food. The spectral quality of the radia

20

ill

i
gy from the lamp determines its usefulness and suitability in a particular

ication. Experiments conducted during 1952 resulted in the developt of a method and associated equipment for use in precise evaluation

ike spectral energy distribution of fluorescent lamps.

[

jtration of Gamma Rays

:companying the increased use of radioactive materials in industrial

jirch and medicine is a growing concern for the harm radiations from

]b materials can inflict on personnel. To aid in reducing these dangers

minimum, the National Bureau of Standards, in cooperation with the

(j:e of Naval Research and Atomic Energy Commission, has been con-

(ing a theoretical and experimental investigation of radiation shielding

2es. This particular program is devoted largely to studies of the disjte radiations travel from their sources and the transformations they

3rgo during the process. The experimental phases of the work are

Ijned to yield information that is essentially general in nature but which

cbe readily adapted to specific problems. Whenever possible, the experits are carried out on a small scale or on a model. In this way, a wide

ofety of investigations can be made of the protection problems associated

I devices such as very large nuclear reactors. Ultimately, the accumlid data will form a basis from which radiation barriers of the correct

tness and material may be designed for economical and safe protection.

bographic Film Dosimeter

compact film badge was developed by the NBS for industrial safety rams and for monitoring in civilian defense. The development re- d from investigations of X-ray effects on photographic film emulsions.

5 studies involved the effects of high-energy X-rays—ranging from those uced by constant exciting potentials of 50 kv to the radiation from a lev betatron—and included a determination of the sensitivity and

.'gy dependence of the photographic emulsions.

^lation Data

ne NBS report X-Ray Attenuation Coefficients from 10 Kev to 100 Mev,

ished in May 1952, constitutes the first of a contemplated series of

l^ys and tabulations of information on various problems of radiation

ics. Radiation physics has grown from a branch of basic atomic re-

:h into an important element of all atomic-energy activities and of large ches of biology and medicine. This broad range of application emphathe need for tabulations of radiation data, supplemented by elementary

•ductory statements of the principles underlying the phenomena under

deration. Moreover, the preparation of adequate tables of numerical

often requires much new research.

-ray attenuation coefficients were tabulated from 23 materials including

Abater, and concrete. The most commonly used materials were chosen

abulation. However, it is possible to obtain coefficients for an element
Installing the 'doughnut" of the new 180-million-volt synchrotron. Mag

field measurements and component testing of the synchrotron are virtually

plete (p. 20).

of any atomic number to a good accuracy by interpolation from the tabul

quantities. The energy range of the incident radiation, 10 Kev to 100 I was covered in 33 approximately equal intervals in a logarithmic seal that coefficients may be obtained readily at all other energies in this r; by graphical interpolation.

A knowledge of the scattering of photons and electrons is essenti applications of radiation theory to research and medicine and is to a 1 degree dependent upon calculations using the complicated Klein-Nis]

formula. Such calculations, presented in graphical form, have now 1 completed for radiations over the energy range from 10 thousand to million electron volts. Wavelengths for Infrared Standards

^ A particularly urgent problem has existed in the spectral region of n imum response for photo-conducting cells recently developed for infn

detection. Wavelengths were known only to one part in one hund]

hence the cut-ofF of filters could not be determined with any greater accur For this reason, the Office of Naval Research has been supporting a prog:

for the standardization of wavelengths in this region of the infrared spectr

To date some 300 lines and bands have been measured. For some of tl the wavelengths have been determined to a high degree of accuracy wil probable error of one part in 250,000.

1)1 22
Iplex Spectra

(le analysis of complex spectra supplies the physicist, the chemist, and

astronomer with atomic data that are needed in the interpretation of erous laboratory and stellar problems. During 1952 the Bureau pracLv completed three such analyses that have been in progress for more

thirty years. In the first spectrum of chromium, Cr i, more than

1 characteristic radiations were measured for wavelength, their in-

.ties were estimated, and the behavior of many of them in high

aetic fields was studied. Similar results were wwked out for more

2,000 radiations that constitute the second spectrum of chromium,

. These data were used to derive, for the neutral and singly ionized inium atoms, the energy states upon which the designations of the

al radiations are based, and the amount of energy required to detach,

lively, a valence electron from the atom and ion. In the first :rum of molybdenum, data on wavelengths, intensities, and magnetic

^rns have been compiled for nearly 9,000 characteristic radiations, use molybdenum is chemically a homologue of chromium, their spectra

d be similar and, in general, this was found to be the case. Wed Spectroscopy

major research and development program in infrared spectroscopy

^related topics is underway at Corona, sponsored by the Department

defense. One of the results of general interest obtained in this work

jthe development of a new method of characterizing the sensitivity and

: of photoconducting detectors. The procedure provides a practical

'f rules for predicting the effect of certain optical and electronic design

(meters on the over-all operating characteristics of infrared detection ms. Studies were also made of physical properties of photoconducting

':tors, and several new experimental methods were developed—e. g., 'utomatic scanning device for the photographic presentation of sensi-

'/ contours, a high-speed rotating mirror device that generates sharp

'!S for use in time-constant studies, and a method for determining the

:ge sensitivity of photoconductors as a function of wavelength.

1 important investigation of the atomic spectrum of hydrogen was

Dieted. This study resulted in the discovery of the first member of the

series and the second member of the Pfund series.

6. Chemistry

wide range of research is conducted in physical, analytical, organic,

'inorganic chemistry. Special laboratories are devoted to organic prove coatings, detergents and absorbents, carbohydrates, metals and

s, pure substances, electrodeposited coatings, gases, and acid-base

•.ators and pH standards. Representative activities included the de- Dment of new methods of chemical analysis, studies of the nature and

23
causes of chemical reactions, determination of the physical constar

substances of interest to science and industry, and development of sp cations for commodities used extensively by the Government. Most

NBS standard samples, critical in industrial quality control and in rese originate in the Bureau's chemical laboratories. There was a m

increase during the year in the research conducted for the Departme

Defense. Also increasing effort had to be given to the standard sa service and to consultative and advisory services for other Govern

agencies. Structure in Detergent Solutions

One of the most interesting and widely investigated problems in cc chemistry is that of the determination of micelle size and shape in detei' solutions. Although a program of study of structure in detergent solu;

is intended primarily to advance understanding of detergents and;

detergent process, the results of such investigations are applicable to a ] extent to a host of other industrially important surface-active substa In addition, detergents can be considered as one of an increasinglyportant group of materials—the water-soluble polymers. During 195': Chemistry Division concluded a viscometric study of dilute aqueous soc dodecyl sulfate solutions. This work lends support to the view that: micelles in this system are spherical.

Labeled Sugars and Sugar Derivatives

Sugars labeled in specific positions with radioactive carbon 14 have

been sought by research workers in the fields of biology, medicine,

chemistry. A project, begun at the NBS in 1951 and sponsored by

Atomic Energ)^ Commission, has yielded a large group of these valu

research tools. Labeled sugars, which are chemically indistinguish

from normal sugars, will be particularly useful in biology, where scien are interested in discovering the mechanism by which a molecule becc

either a source of energy or contributes to the structure of living cells, cause these sugars have an atom of carbon 14 precisely placed in t structure, they can be traced through the complicated chemical react

vital to animal and plant life. During the current year methods were perfected for the preparatioi

12 more C^*-labeled sugars and sugar derivatives. Substantial quantitie these substances were distributed for research in biology and medic' Methods were published for the preparation of glucose- l-C^"^, mann

l-C^^, fructose-l,6-C^* and lactose-l-C^*. Significant improvements v made in methods for the preparation of D-arabinose-l-C^^, D-ribose-1-' D-fructose-l,6-C^*, D-glucuronic acid-6-C^^, D-glucose-6-C^*, and D-arabin

5-C^*. Simple methods were developed for the assay of C^^ in the term;

positions of reducing sugars. The value of reaction with radioac

cyanide for the determination of minute quantities of reducing sugars indicated and analytical procedures were devised. 24
(Bureau is investigating the use of dextran as a blood plasma substitute (p. 27).

"^i dextran solubility in methanol-water solutions is tested by dropping methanol

c:. burette into water solutions of dextran. Right; equilibrium ultracentrafuge

center) used in study of blood plasma substitutes and other high polymers

4

i^ganic Compounds

tiorganic chemistry is assuming increasing importance because of the

)cl>id adoption by industry of many new inorganic compounds. Particuit f!j7 in the field of metals, where new uses and shortages have driven poten-

(iusers to seek substitutes and new materials, more detailed knowledge of

j chemistry of newer metals is needed. Continuing work is needed to

aire chemical knowledge of metals like titanium, a light metal which is Itrong as steel and corrosion resistant, and zirconium, a strong heat- ptant material used in atomic piles. Several contributions were made

I '{lis field by the Bureau during 1952. One was to the analytical chemistry

Fitanium, zirconium, silicon, barium, strontium, calcium, magnesium.

[ninum, and iron through the development of a reliable method for rmining the chemical composition of titanate dielectrics. An outstandfeature of the method was the discovery of an extremely sharp separaof barium from strontium. This same reaction effected the preparaof strontium-free barium salts and of barium-free strontium salts, he discovery that silver can be precipitated in metallic form from amiacal silver solutions by hydrogen peroxide made available a longted laboratory method not only for the purilication of silver but also reparation in a finely crystalline state. new method for preparing cobalt-free nickel salts made available for

irst time nickel salts suitable as standards for measurement of magnetic

i^ptibility, spectrochemical analysis, and for developing testing methods

ickel salts as reagent chemicals. In this connection the potentiometric

tion of cobalt in nickel salts by means of ferricyanide was extended to

^titles as small as 2 micrograms in the presence of one million times as h nickel. method was devised for freeing zirconium of common impurities and

jreparing zirconium sulfate and oxide. 25
Dissociation Constants In connection with the Bureau's program for establishing pH s' ards, a procedure was developed for the resolution of overlapping diss tion constants of polybasic acids and, hence, for determining the com

tions and pH values of solutions of salts of these acids. The methoc

been applied successfully to the determination of the constants of D-tai acid and, in modified form, to phosphoric acid over the range of tem]'

tures ordinarily encountered in pH measurements. These acids and

salts are widely used as constituents of buffer solutions for the regul; of acidity. The determination of accurate values of their dissociation

stants is expected to be of practical as well as of theoretical applicatioj , Chemical Thermodynamic Properties In the continuing project on the collection and critical evaluation o; . chemical thermodynamic properties of substances, which has received p2

support from the Office of Naval Research, a milestone was passed witl I publication of a 1,200-page Circular (C500) entitled Selected Valui

Chemical Thermodynamic Properties. This volume contains values o; heat and free energy of formation, entropy, heat capacity, and heats temperature of transition, fusion, and vaporization for all inorganic ( pounds and of certain organic compounds (those containing not more i two carbon atoms), where such data were available. Complete refere

to the original literature are given. Loose-leaf tables to supplement

data in the circular and also to give high-temperature thermodynamic p

erties of chemical substances are being prepared and distributed. Pure Substances

The evaluation of purity of chemical substances that are "nearly" j has been less successfully handled in the past than the analysis of ci mixtures or the assay of extremely pure compounds. Even in the la case, little indication is usually attained about the nature of impurities, cent developments in the area of nearly pure substances have yielded ii precise information on the kind of impurities that are present. A i apparatus for the fractional melting of completely frozen material is u^ As the frozen material melts, the less pure portions are withdrawn first,

^ successive portions tend to wash away that which has preceded them u the entire sample is melted and divided into separate containers. Dui' the entire operation the system is sealed so that there is no contact with^' or other modifying influences. Fractions obtained in this way are \! mately subjected to purity evaluation by standard procedures. Cryoscc

estimations of purity combined with mass spectrographic analysis have b

especially valuable. Present uses have been confined to projects o defense nature, but potential applications occur in the entire range

chemical and industrial fields. The procedure is similar to fractional ( tillation in that total fractionation is attained and no portion is wasted. : 26
, )d Plasma Substitutes

In increased stockpile of blood plasma and "substitutes" for use either

"^^''he armed services or in civilian defense is urgently needed. The Na-

^\^\al Research Council is coordinating a nation-wide research program to

"!"|t in the creation of a stockpile adequate in quantity and quality. The

^I'i^au is participating in this program by making a study of the properties

jlextran, a polysaccharide of high molecular weight derived from the

lientation of sugar. For clinical use, a narrow molecular weight range

extran is required, the lower limit being governed by the permeability

he capillary membranes and the upper limit by the tendency of high

scular weights to promote clumping of the red blood cells. The Bureau

studied various methods for evaluating molecular weight distributions,

bding the chemical measurement of end groups, light scattering, ultra-

';!Tifugal methods, solubility in solvent-nonsolvent mixtures, and viscosity,

'j; relations between viscosity, molecular weight, and molecular shape ^ studied for dextran produced by a method developed by the Northern

'ional Research Laboratory (Department of Agriculture). Procedures

jcharacterization of the molecular weight distribution by a combination

'^actional precipitation and light scattering, already embodied in a mili1 specification, have been improved in collaboration with the Department

igriculture and with industry. Copper reducing values of dextran were \ to determine number-average molecular weights. This method is based

:;he postulate that a molecule of dextran has the same reducing power

molecule of isomaltose. Comparative studies were made of the deteration of reducing end groups by several methods. Optical rotations,

iactive indices, and densities were measured on clinical dextrans from a

ety of sources. A study of the branched structure of the material was km in which the 1,6, the 1,4, and the 1,3 linkages are determined by

pdate oxidation and isotope dilution methods.

7. Mechanics

lesearch work in the field of mechanics includes fundamental mechanics

iolids, liquids and gases, improvements in the precise measurement of

:hanical quantities such as density, mass, force and pressure, investi- ons in the field of aerodynamics, acoustics, structures and hydraulics,

|i selected instrumentation and apparatus. Investigations in progress uded architectural acoustics, measurement of sound pressure at low

jjuencies, and precise measurement of pressures up to 200,000 psi (for lication in military work and the chemical industry) and of pressures ow 0.0000001 psi for aeronautic and laboratory use. Other studies ude the measurement of turbulence with hot-wire anemometers at speeds

Dw and above the speed of sound, the impact experienced by an airplane

anding, the measurement of backflows of salt water along the beds of 27

I
Right: the speed of sound in a liquid contained in a cell (arrow) is measured

tinuously by the ultrasonic velocimeter (p. 28). Top left: a pulse transfc wound on a ferrite toroid (left) for use in a blocking oscillator (right) havin |' rise time (p. 28). Bottom left: two types of hot-wire anemometer heads us the Bureau in aerodynamic research (p. 29). The wires, 0.0002 inch in dian

are soldered between the needle-point prongs. ;

f rivers, and the performance of the very large orifice meters now reqi

by the natural-gas industry.

^ Sonic Measurement of Physical Properties \ With the increasing use of automatic process controls by industry,

methods for measurement of physical properties are needed. Two i instruments reported last year continued under development during ij One is an instrument for measuring, by an acoustic technique, the visci coefficients of gases; the other is a device for measuring and recon

continuously the velocity of sound in a liquid. A by-product of t investigations was a very fast blocking oscillator, having a rise time of than 0.02 microsecond and a duration of less than 0.06 microsecond.

Sound Reverberation

The recording correlation meter was improved and applied to stud;, in detail the degree of randomness of the sound field used in making^

verberation room measurements. It was found that the measured > relation agrees with the theoretically predicted value, with the poss exception of high frequencies, where the researches are being contim

Viscosity of Gases

Several measurements of the viscosity of gases, sponsored by the Natic \ Advisory Committee for Aeronautics^ were made on apparatus develo

in previous years. Measurements were made on a sample of gaseous c( I bustion products at a temperature in excess of 2,000° F at approxima

atmospheric pressure. Almost no reliable data on the viscosities of 28
|:his and higher temperatures are available. They are particularly useful

jldeveloping aircraft engines in which both the temperatures and gas

bcities are high. Measurements conducted on dry air under pressures

to 300 atmospheres and temperatures up to about 600° F and on moist

over a less extensive range of temperature and pressure agree closely

jh values believed to be the best previously available.

it-Wire Anemometers at High Speeds

jiiecause the cooling of a fine heated wire responds quickly to changes in

Ij.peed, the hot-wire anemometer has proved to be more useful for the

ill estigation of turbulent motions in air than any other known device.

)nsored by the National Advisory Committee for Aeronautics, the Bureau

low exploring the possibilities of this instrument in the transonic and

iersonic speed range. Anemometer wires can have a diameter no greater

in a few microns if there is to be any hope of adequate frequency response,

jus the most critical problem has been to find a suitable wire material with

I'tecient strength. Tungsten, used until very recently, has several disad5|c|ttages and cannot be procured in sufficiently small diameters. Within

4]' past few months, rhodium-platinum alloy wires in diameters down to microns have been investigated and found to be successful. While still Idler wires can be drawn, it is not yet known whether they will withstand

wind loads.

ig:ue Strength of Structures

jvluch of the research on the failure of structures by fatigue under fluctuig loads has been directed toward determination of the behavior of the

jtals by using carefully finished specimens and testing them to failure

der fluctuating loads of constant amplitude. Fatigue strengths so deterjied are greater than safe design stresses for machine elements and primary

ments of structures because of the absence of stress raisers, such as holes,

iifets, change of section, etc. The discrepancy between these two stresses lependent not only on the shape of the part but also on the material and

thod of fabrication. The relationship between the fatigue strength of the basic materials and

fatigue strength of aircraft structures is of particular importance because

ght limitations make the efficient use of materials essential. At the

luest of the Bureau of Aeronautics, a program of tests designed to deterle the relation between fatigue life of a simple structure and that of

ipons made from the same material has been completed. Seven simple

ited beams, constructed by an aircraft manufacturer, were subjected to

leated bending loads in a specially designed machine. This machine per- ted varying the deflection of the middle of the beams with respect to the

is to produce failure in from 1,200 to 500,000 cycles. Stresses in the

ige were computed from the measured loads required to deflect the beams,

ooth coupons of the material used in the beams were tested over the same

range under repeated axial load and the corresponding stress-life relation228268—53 3 29
ship determined. The resuhs showed that the beams were about h; ^ strong as the basic material for failures at the same number of cycles i range from 1,200 to 500,000 cycles.

Another difficulty in predicting the behavior of structures in service

results obtained in standard laboratory fatigue tests is due to the u

fluctuating loads of constant amplitude in the standard test, where

service the maximum load varies widely from cycle to cycle. An air for example, usually has many cycles of low loads with only occasional

of high load associated with landing, taxiing, maneuvering or flight

unusual weather conditions. At the request of the NACA, the efTe axial load fatigue life of smooth aluminum-alloy sheet coupons subject

two stress amplitudes was measured in special testing machines. Da

several hundred smooth specimens of two aluminum alloy sheet mat

over a wide range of stresses and numbers of cycles indicate that fo

• stress levels the linear cumulative damage theory can be used to pr

life with an accuracy of 40 percent in the worst case. In the above tl: it is assumed that the damage in terms of life at any stress level is equ

the number of cycles applied at the level divided by the number of required to cause failure at that level. When the sum of the dama

equal to unity, the specimen will fail. Stiffened Skin for High-Speed Aircraft

In order to achieve high aircraft speeds, the wings of our most mo

airplanes are made extremely thin to reduce drag. At these high sp the wings are heated considerably by the friction of the air flowing

them, and their strength is thereby reduced. At the request of the > Bureau of Aeronautics, a combination of sheet and stiffening materic small total thickness and high strength was developed. This construe

consists of two plates separated by bar-type stiffeners to form a sand\>

The plates and stiffeners are assembled by long rivets passing through

stiffener and both plates of the sandwich. An advantage of such a • struction is that it can be readily tapered in both width and thicknes

fit the needs of a particular aircraft. An experimental check was carried out to determine if this type of < struction is strong enough to carry the extremely large edge-loads for w]

it was designed. Seventeen specimens were tested under compressive Ic simulating conditions in the upper wing surface; two specimens were te: under tensile loads simulating conditions in the lower wing surface,

experimentally determined strength was in good agreement with 1 predicted by proposed design methods.

Tests were conducted to determine the effect of temperature on

strength and distortion of wing panels of the abo\'e sandwich type anc other high-strength types. It was found that, at a uniform elevated t( perature, the strength was 20 to 30 percent below the strength of the pai tested at room temperature. Temperature gradients through the p2

thickness were found to cause some warping of the specimens but to leave 30
A

i ): limit-load gages (circled) installed on the underside of the wing of a F8F

,Ltmman "Bearcat" (p. 31). (Photo courtesy of United States Marine Corps.)

Idle: side view of partially assembled NBS limit-load gage showing its three

lor components: the arm (A), cam (B), and gage points (C and D).

';r-aU strength relatively unchanged from that corresponding to the

rage temperature.

-nit-Load Gage

\ limit-load gage recently developed by the NBS provides a simple means

determining whether basic structural components of operational airjft have been stressed beyond safe limits. Designed and developed for Navy Bureau of Aeronautics, the gage indicates visually when wings

Dther structural elements have been subjected to loads equal to or greater n a predetermined load beyond which permanent damage may occur,

'general the imposition of such loads, which are unpredictable, may be

ised by rough air, landings, or a sudden change in flight attitude. The

'^e has been extensively tested for use by high-speed aircraft, and its cess there suggests its use on other types of aircraft and possibly on bridges

d similar structures. The limdt-load gage is extrem.ely simple and consists

.y of an arm, a cam, and gage points. Overload is indicated when the

1, initially cocked above the cam, flips past it. 31
Pressure Drops in Oxygen Flow Systems

The pressure drops during gas flow through the components of a s) i:\ containing tubing, fittings, and orifices must often be computed when iid systems are being designed. Any such calculation of pressure drop ir volves many uncertainties and estimates. A theoretical study has -til made for the Aero Medical Laboratory of the Air Force of the pre iri* drops in oxygen equipment systems. Methods of computation for hi various components for the various flow regimes were developed into u 'li: form. These methods, with obvious modifications, are applicable to c ifr; gases. Laboratory Centrifuges

An ultrahigh centrifuge has been completed. This centrifuge is cap

of producing an acceleration of 60,000 g on a 1-lb weight. Prior to development of this equipment, stresses of this magnitude could no

produced in laboratories. A second centrifuge has been developed to heavy items. This centrifuge will produce acceleration forces of IC on equipment weighing 100 lb. This centrifuge allows testing of compli'' units. ) Four-Inch Air Gun

Information about stresses due to acceleration is frequently needec

scientific laboratories. An air gun having a 4-in. diameter has been C; structed at the Bureau. This air gun is 96 ft long and is operated by li pressure air to impel the specimen through the air gun. The specimen

received in a catcher box which can be filled with various materials produce varying values of deceleration. The NBS air gun is a depart

from the usual methods of measuring acceleration stresses : such guns h

usually been activated by high-pressure air to produce the desired accelt tion stress on acceleration of the specimen; in the new gun, low-pressure

gradually accelerates the specimen, the desired stresses being produced

deceleration of the specimen as it hits the catcher box. High-Capacity Load Calibrating Devices

The calibration of four 3,000,000-pound-capacity compression dyr

mometers for use in calibrating large testing machines has been complet

These dynamometers can be used together to measure forces up to 12,0C

000 lb. Prior to the development of these dynamometers, which make i of attached wire resistance strain gages as a part of their load-indicati systems, the highest load which could be accurately measured was appro

mately 2,600,000 lb. It is expected that the new dynamometers will be u« to calibrate a considerable number of the larger testing machines at reduced cost and a saving in time. , 32
^1 Dam-Break Problem

he classical solution of the Saint-Venant problem for the flow of water

n|rr a dry bed resulting from the breaking of a dam disagrees with experi-

)pjcital results by as much as 50 percent, owing to neglect of the hydraulic

s

j stance effect. In investigating this problem the Bureau found a new type

re^c boundary-layer phenomenon, or "tip effect." This tip effect will be

ofnfsent not merely in the specific dam-break flow but more generally wherj_ir a positive wave advances along a dry channel. The aerodynamic

^^jnterpart of this hydraulic problem has also been analyzed, which is case of a gas escaping into a vacuum (as, for example, in a vacuum2 supersonic wind tunnel) . The problem also has been further gener- ed to encompass a pipe with variable cross-section. Experiments are

iig conducted to parallel the theoretical investigations of the hydraulic

Iblem. One purpose of the experimental work is to check the mathematijresults; another is to amass data to determine the extent of applicability

ijthe Chezy resistance law (which is a steady-flow formula) to highly

Wady flows.

lijisity Currents

i rhis project, reported last year and supported by the Office of Chief of

ij^ineers (Department of the Army), has been continued. The emphasis

(j

been placed on the problem of salt-water intrusion from a tideless sea a rectangular channel in which fresh water flows toward the sea, thus

ulating a river mouth. Three series of tests were completed in investi-

|[ions of the effect of the densimetric Reynolds number (Reynolds number

rj^ltiplied by a density ratio) : effect of channel width and slope on propapion of the saline wave front in the fresh water, form of the wave front,

configuration of the wave front when its motion has been arrested by

[j' fresh-water current. Each series of tests was carried out with six difcnt salt-water densities and with nine different river velocities for each

lisity used.

8. Organic and Fibrous Materials

The Bureau investigates rubber, plastics, textiles, leathers, and papers.

I2se natural and synthetic materials are considered nondepletable reirces and are of great importance to the national economy. The textile ustry is the nation's second largest while the comparatively new field of

sties has already assumed fifth place in size and is still growing. These

organic materials have certain common characteristic properties due

he long, chain-like structure of their molecules. The complex molecular

icture of high polymers, combined with their refusal in many cases to low the laws of classical physics, has made it very difficult in the past to ain definite fundamental knowledge of their properties. In recent years, vever, rapid progress has been made in the science of high polymers, and

t/ techniques have been developed for measuring their properties and

33
studying their reactions. Many of the new techniques—such as X-ra^ lif.; fraction, infrared spectroscopy, and electron microscopy—are being

ployed by the Bureau to obtain a better understanding of the fundam U

properties of high polymers, both natural and synthetic.

The research program has included studies of rheological properti oi synthetic polymers, physiochemical structure of fibers, chemical natu: c!. collagen, chemical reactions involved in the deterioration of polyr ml materials, and structure of human tooth enamel and dentin. Applie< iti search on polymeric materials included efforts to make papers and pk id having properties outside the range of those previously thought poss le., Significant contributions have been made in applications of polymeric [^ terials to windows on aircraft, structural laminates reinforced with jm

fiber, self-curing resins for dentures and dental fillings, and sole leath(

improved abrasion and fungus resistance. Research was also undert; e to extend the uses of organic materials to replace metals and other i stances that are in even shorter supply. The reopening of the Gov*

ment synthetic rubber plants greatly increased the demand for stanc. rubber samples and called for investigations leading to better methoq

quality control. s Deformation of Elastomers

' A knowledge of the fundamentals of deformation and flow behavioi, elastomers is valuable in developing new mechanical uses of this rap

growing class of materials. Since polyisobutylene can be regarded 2 prototype linear elastomer, an extensive investigation of its deformation . flow properties has been undertaken. The studies showed that the tempi

ture dependence of retarded elasticity follows the same law as the t\. perature dependence of viscosity. The logarithm of the viscosity is obser

to vary linearly with the inverse square of the absolute temperature and | slope of this relationship is found to be independent of molecular weighj. Structure and Composition of Collagen

' Only within recent years has the art of tanning started to develop 01 truly scientific basis, since tannins and hide alike are such complex chemi 1 structures that adequate methods for studying them were not previoi

available. The Bureau is using some of these modern methods in study

the composition of collagen, the most important constituent of hide

leather-making purposes. By application of chromatographic techniql the polar amino acid content of collagen, hide powder, and gelatin \

determined. The glutamic acid content of these materials was also e: mated by conversion of this amino acid to pyrrolidone carboxylic acid. Structure of Cotton Fibers

The extent to which the available surface of cotton increases when^

contact with water is believed to influence the behavior of the fiber duri processing and use. As a part of an investigation on the structure of cott 34
irs surface area measurements were made on a number of cottons that been stabilized, in the expanded condition resulting from swelling in

^er, by a process of solvent exchange. Surface areas, calculated from

quantities of nitrogen adsorbed at low temperature by the expanded cots, ranged from 4 square meters per gram for a partially methylenated

:on to 148 square meters per gram for a mercerized cotton of low ma-

.ty. Purification and mercerization resulted in increases in the surface

liable after swelling, methylenation produced a decrease, ethylamine

itment had no effect. The results indicate that the method will prove

ful in evaluating the effects of various treatments on cotton and other

ulose fibers. ucture of Tooth Enamel and Dentin

^^'jjreat differences exist in the resistance of the teeth of different individto decay, and these differences are thought to be associated in some way

Sh the manner in which the hard, calcified tooth structures are deposited.

'I learn more about the problem, the Bureau, in cooperation with the

'^tlierican Dental Association, has been investigating the structure of teeth

^^\2L variety of physical and chemical techniques. For many years it has

jn known that human teeth fluoresce, emitting visible light when irradi-

'jd with ultra-violet light. Since in general the fluorescence of a substance

jery sensitive to small differences in structure or composition, it was felt

'|.t a thorough investigation of the fluorescence of enamel and dentin might

P^tbg out details of structure not made apparent by other methods.

Certain developmental or growth lines in the tooth were revealed clearly

'^ fluorescence photomicrographs obtained from very thin tooth sections pj^minated with high-intensity ultraviolet radiation. Fluorescence spec-

'Hscopy methods were used to study the differences in composition of the

I'jious areas of teeth. Crystallographic methods were used to investigate

' position of the carbonate content of tooth structures. Many different

(ibonate apatites were synthesized and studied by means of X-ray diffrac1 methods and by petrographic microscope examination to determine the

l^ects of including carbonate in the apatites. The discovery of a particle

roximately 50 Angstrom units in size in enamel and bone by low angle

^ iray scattering and line broadening methods gives additional evidence to

import the theory that the carbonate content of tooth structures is present

ijnclusions rather than as an integral part of the structure.

[|tf-Curing Dental Resins

Self-curing dental resins are of interest to the armed forces because

-y can be used for direct insertion into cavities and in making artificial itures without special heating equipment. In cooperation with the

aerican Dental Association, the Veterans' Administration, and the ^partment of Defense, an investigation of the properties and clinical jiavior of these resins has been carried out. The shrinkage of the self- ring resins was found to be several times that of any other direct filling

35
Natural fluorescence of human teeth reveals new details in tooth structure (p. 3 A recording spectrometer (center) is one device used to analyze fluorescet' The spectral intensities of various areas of a tooth section being subjected to ul violet light (far left) are automatically recorded on the chart at right. Top inP shows a dentin-enamel junction in a tooth section photographed under visible liji Bottom insert shows a tooth section excited to fluorescence by ultraviolet li|

material. This large shrinkage and the high coefficient of thermal

pansion, about 8-10 times that of tooth structures, form probably th greatest disadvantage. The opening and closing of the space arounc;

resin filHng, resulting from the difference in expansion of the resin and

;

the tooth structure, produces a seepage of oral fluids in and out of t space as the tooth is alternately cooled and warmed. This exchange

!

fluids may establish conditions favorable for tooth decay. Tests for irn other properties gave both good and poor results, but clinical studies show

that experimental dentures in service up to 2 years have been satisfact in most cases. Glass-Fiber Reinforced Plastics The use of glass-fiber reinforced plastics has increased greatly in ' last few years. The armed services have found this type of matei

adaptable to scores of applications, such as radomes and other parts

aircraft, containers, boats, prefabricated shelters, skis, and toboggans. T

variety of applications requires many data on design and production qua]j control. Under the sponsorship of the NACA and the Wright Air Develc 36
I t: sheet of aircraft glazing, stretch-formed in the shape of a hat, is removed from acuum forming vessel (p. 38). Right: apparatus used for determining the

I "Sting strength of leather (p. 37). Plungers used in the tests are on the machine

I'lel.

I snt Center, many investigations of this material have been undertaken

the Bureau. It w^as shown that close control of the many variables volved in production makes possible the fabrication of reinforced plastics th more uniform quality, greater strength, and improved electrical

joperties.

jiffness of Paper

t The stiffness of paper is a property of importance in a w^ide variety of

!; uses, such as case liners for shipment of military materials, cards for

le in mechanical punched-card systems, and currency paper. Heretojire there has been no very satisfactory method for measuring this property.

, new instrument for determining this property has therefore been de-

^ doped at the Bureau. In the NBS device, the specimen is bent through

given angle, and its stiffness is measured as the torque in a wire suspension.

/ varying the size of the supporting wires and the angle through which

^le specimen is bent, papers having a wide range of stiffness can be tested ithout difficulty in whatever dimensions they happen to be available.

. he NBS Stiffness Tester is also expected to prove useful in testing the

iffness of such materials as thin plastic sheets and textiles.

jurst Test for Fibrous Sheet Materials

I For many years the Mullen tester has been used for measuring the burst-

^ig strength of fibrous sheet materials, particularly paper and leather. Yet

: le use of this device has been continually accompanied by difficulties. Juring the year two research projects intended to obviate such difficuhies

/ ere completed. In the paper industry, the use of the device is so widejoread that it seemed preferable to try to overcome the difficulties, retaining

jtie use of the Mullen tester, while in the leather industry it seemed

37
practicable to develop a better method with different apparatus. 1

was found in a device having a cyUndrical steel plunger with a hemispheri

tip, adaptable for use with a testing machine of 2,000 pounds capacity.

Multiaxially Stretched Plastic for Aircraft Canopies

Transparent acrylic plastic is used for aircraft canopies rather than g] because it can more readily be formed to the streamlined shapes requi:

and is lighter in weight. However, this material has a tendency to fo tiny cracks or fissures. On some pressurized military airplanes a lamin

made of a soft vinyl butyral plastic sandwiched between two outer lay of the acrylic plastic is used to obtain greater protection against shatter: of the enclosure when struck by shrapnel. However, the laminate is ch

acterized by increased weight and a greater tendency to craze. W(

recently conducted at the Bureau showed that by hot-stretching the acr)

plastic sheets the material is made essentially craze-resistant and takes o]1

1

laminar structure which gives it the improved impact characteristics of 1 acrylic-vinyl laminate.

1 n Recovery of Asbestos

At the request of the Bureau of Ships, the Bureau studied the reclamati

of asbestos fiber from various kinds of molded and cloth insulation discarc | in large quantities during the repair and refitting of ships. The study

volved the removal of extraneous materials and the reduction of the clear cloth to fiber form. It was found that the asbestos could be reclaimed

digesting the insulation in either dilute acid or alkali and reducing the cle cloth to fiber form in a paper pulp beater. The recovered fiber was acce

able for making paper and molded compounds. The industry is interest

|

in the use of the reclaimed asbestos as a filler in molded plastic compoun

paper products, and molded laggings (insulation). The recovery of

bestos from the discarded pipe insulation will aid in relieving the shorta of this critical material.

'

9. Metallurgy

Research and development activities in physical metallurgy include t preparation of metals and alloys by melting, casting, hot and cold workii

and heat treatment. They also include the determination of structu

properties, and behavior under normal and abnormal conditions of u

In general, this program is directed toward a better understanding of met;

in order that new or improved metals and alloys may be developed. Sin

1950 the basic and applied studies in physical metallurg)^ have been grea- stimulated by the defense effort. Studies this year have covered the mech

nism of the deformation and failure of metals, the effect of adding sm. amounts of magnesium to cast iron, and the development of several devic designed to speed metal fatigue tests. Considerable effort was devoted

the study of corrosion of metals, as part of a continuing study.

'

38
t: McKee Worker-Consistometer used at NBS to investigate the rheology of

^Iber solutions, (p. 34). The device was originally developed at the Bureau to dy the effect of mechanical working on greases. Right: uniform polishing of

:al fatigue test specimens (p. 41) is accomplished by using this polishing

pel, consisting of a large number of metal spring leaves pressing against an

iasive belt.

jrrosion

"Studies of the corrosion of metals have been intensified because of the

'^.reasing awareness of the loss to the national economy from this source.

irrent NBS efforts to reduce this loss include studies of the basic mecha-

' ms of corrosion, determinations of the relative merits of known materials

; resist corrosion .... in various environments, and evaluation of protective

' 'itings and protective devices. Additional data were secured on the underground corrosion of metals

'l)m exposure sites maintained throughout the country; new theories of

s mechanism of the corrosion of metals underground and of protection

^ainst this corrosion were developed ; and experimental confirmation of the

:pre important of these theories was obtained. The theoretically derived

lue of —0.85 volt for the cathodic protection of steel in underground

rvice has been confirmed experimentally, and it has been demonstrated

at the rate of corrosion of metals underground can be determined in situ

. thout disturbance. Studies were completed on the corrosion of galvanhd iron and of low-alloy irons and steels after underground exposures up

I 17 years.

I Stress-corrosion cracking, caused by the combined action of stress and

|rrosion, can be responsible for the spontaneous service failure of objects

jnging from brass cartridge cases to stainless-steel coffee urns. Although

e problem is an important one, much remains to be learned about the .echanism of stress-corrosion cracking. Corrosion is generally considered

^ be an electrochemical phenomenon, involving the flow of minute electrical

Jirrents between areas of different potential. When most metals are exDsed to ordinary atmospheres, a thin oxide film is quickly formed that tends

I 39

L.
to protect the metal from further corrosion. According to the most i erally accepted theory, which the NBS study tends to confirm, stress-corro cracking starts with a scratch or break in this protective film. When

protective film is broken through, the freshly exposed metal is more ami*

(more negative) than the surrounding film-covered surface, and if moisM

is present an electric current flows that causes the metal to be removed f] the exposed area. Deformation and failure of Metals

The failure of metals due to fatigue under stress begins as a brittle cr which spreads until the remaining metal can no longer carry the lo sudden and complete fracture then occurs. The Bureau is attempting

learn more about the mechanism of this process. A valuable and useful property of ductile metals is their ability to beco

stronger and harder by cold-drawing or other cold-working. This incre

in strength is usually accompanied by a decrease in toughness, especij

when specimens are tested in tension at the same temperature as that u

in cold-working. Investigation at the NBS of the creep of high-pui

copper was extended to include cold-drawn copper. Specimens w

tested for their creep characteristics at 1 10°, 250°, and 300° F with consti loads in tension. At each test temperature, the cold-drawn copper \' markedly superior to the annealed copper in resistance to creep and

fracture. This superiority in strength, however, was accompanied b)

considerable loss in elongation at fracture; for equivalent second-st2 creep rates and temperatures, reduction of area at fracture was about same for both forms of copper. The mechanism of the deformation and failure of metals at vari temperatures and under different kinds of deforming stresses was the si ject of several investigations during the year. Short-time tests at hi temperatures showed that strain aging at about 300° F and irregularit in ductility at 500° to 700° F are encountered in high-purity nickel, j investigation of the fatigue of metals at ordinary temperatures showed th understressing reduces incipient fatigue damage and makes the metal 1( sensitive to the detrimental effect of notches. Recent results showed th when ingot iron is deformed at low temperatures, slowly in tension rapidly in impact, a shock wave is not essential to the formation of defc^ mation twins and the newly formed twins are as ductile as the parent met

These findings are contrary to recently proposed theories. Structure of Metals

Addition of small amounts of magnesium to cast iron has received i: creasing attention recently because it imparts desirable ductile qualiti to the iron. It was shown during the year that the nodular graphi

produced by the action of magnesium on molten cast iron has the san

structure as the flake graphite normally found in cast iron. The improve

properties of the nodular iron therefore are due primarily to the shaj'

40
dy of the deformation and failure of metals at low temperatures resulted in find-

;s contrary to proposed theory (p. 40). A specimen submerged in a bath of uid air is being tested under a 50,000-pound-capacity testing head.

1

^ the graphite particles, not to their composition or internal structure,

[i-uctural studies showed that certain microstructural constituents can be

Ijentified more easily and rapidly by optical microscopy with polarized light

' an by previously used procedures such as X-ray diffraction. The solubility of chromium carbides in 18 chromium-10 nickel stain-

^;;s steel was shown to be much lower than was previously believed. This

' cans that only those steels that have been "stabilized" by titanium or

li'lumbium can be relied upon for immunity to intergranular embrittlement

iider severe conditions of service.

.1

; .etal Fatigue Tests

i Several devices recently constructed at the National Bureau of Standards

p-e proving valuable in speeding metal fatigue tests. The new auxiliary

'kt equipment includes devices for stopping the testing machine when a

iQall crack forms in a specimen, apparatus for the uniform polishing of

I 41
fatigue test specimens, and a machine for fatigue-testing thin sheet sp' mens in bending. Because metal fatigue, or fracture under fluctual

stress, is the principal cause of service failure of machine parts, the la ratory study of fatigue of metals is of major importance. The continu' ^ fatigue studies at NBS rely largely on commercially available tesf machines. Occasionally, however, it is found necessary to supplement tl^ machines with specially-designed equipment such as the present new devi10. Mineral Products

Research and development in the field of the nonmetallic inorganic n ic eral products is concerned with the determination of the constitution, str < ture and physical properties of these minerals with a view to their m ai efficient utilization for defense purposes and for civiHan use. Such prodi r include ceramic oxides, glass, refractories, porcelain enamels, building stQ

concreting materials, lime and gypsum. During 1952 the Bureau conduo. d mvestigations pertinent to the development of atomic energy. The dev, j opment of refractories for jet engines continued, and improvements w.; m made in ceramics with piezoelectric properties for special ordnance appli;, d tions. The synthesis of useful silicates, especially asbestos, received increiLu ing attention. Detailed work on the structure of specific crystalline cc pounds of interest in cement technology proceeded satisfactorily. Progi was made in the development and standardization of test methods for cem^

and concrete. Pioneer work was undertaken in a study of the elastic a plastic properties of single crystals of ceramic oxides. Further progress \

made in a study of the constitution of glass, especially with regard to 1 surface properties and phase relationships at high temperatures.

Refractory Concretes | Refractory concretes are composed of aggregates consisting of calcir ,., fire-clay or crushed used firebrick and bonding material of high-alumii

hydraulic cement. While it is known that this type of refractory mater

has important advantages over other types in moderately high temperati

installations such as incinerators or heat-treating furnaces in steel plan

little is known of the properties in the transition zone of intermediate tch peratures. At low temperatures strength is obtained from the hydrau?

bond; at high temperatures a ceramic bond is developed. An invesi gation of properties was carried out by weight-loss determinations at vario? n temperatures, by differential thermal analysis, and by strength determiij in tions at a number of different temperatures. Strength decreases were fouD

to be associated with losses of water from the hydraulic cement at temper t tures below 300°C. In the range between this temperature and that r which the ceramic bond was developed (about 1200°C), there was liti change in strength. Although the maximum loss in strength exceeded r ^ percent, at no time was the residual strength insufficient for the loa

" encountered in the types of installations for which they are intended.

42
Institution of Glass

,:|}leasurement of the physical and chemical properties of simple glassjaiing systems is providing the experimental basis for a much needed theory

Jhe constitution of glass. For example, a recently completed study of the

ilses and liquids in the system BaO-B^Os-SiO^ (of importance in the

i^ipufacture of optical glass) indicates by measurements of refractive indices

iM other properties that such glasses are not simple solutions of the oxides. hew apparatus for the accurate measurement of index of refraction of

h, simple in construction and obviating the use of ground and polished

jiples, has been developed as a byproduct of this study. The index of

rlri-action can be determined within ± 1 in the fifth decimal place with the

im- apparatus. One of the important uses of the instrument is in conoiling the index of refraction of optical glass: the sample can be prepared

u3 measured in a few minutes.

ct[nvestigations of properties of simple glass-forming systems have been

nended to include alkali borates. The introduction of alkali oxides into

4ic acid is accompanied by strong attractive phenomena, shown by a Aume contraction of the boric oxide. At low alkali oxide concentrations

i^i change of surface tension with temperature is roughly the same as that dpure boric oxide. This is an indication of the strong attraction of the

)nid borate for the alkali. The attractive force varies inversely as the

ife of the alkali ion, the small lithium ion being pulled away from the suri:e more than the larger sodium or potassium ions. ramie Dielectrics The assurance of an adequate supply of ceramic dielectrics, essential for

gently developed electronic devices, is extremely important. Heretofore

e formulation of bodies to duplicate the performance of useful ceramics

tailed much time and effort, but analytical techniques perfected in the

iiemistry Division have greatly simplified this problem. On this basis,

iar experimental bodies made at the Bureau proved to be the equal of immercial ceramics with respect to dielectric constant and were superior

I power factor and temperature-capacitance characteristics. ^Life tests of direct-current volume resistivity of ceramics at 200 °C reveal

fceptionally good insulation properties of dielectrics made from calcium

ianate and from mixtures of titania with oxides of rare-earth elements,

ijch as neodymium and lanthanum. A resistivity of more than 10^^ ohm-cm

maintained by these ceramics at 200°C during the schedule in which

increase of 5 volts per mil was made at 7-day intervals for the range of

ijto 30 volts per mil. This behavior necessitates a modification in the conpt currently held that all titanates have poor insulation properties when

bjected to 5 volts per mil or more at elevated temperatures.

^ramies for Atomic Energy

Refractory ceramics with favorable nuclear properties are of interest to the

tomic Energy Commission for a great variety of high temperature applica43
Radioactive cobalt is used as a tracer to study the adherence of porcelain ename. i steel (p. 45). The specimen is placed in "lead pig" (left), which contain i Geiger-Miiller tube. Radioactivity detected by the tube is counted on sci\ (center).

tions. Fundamental data concerning the thermal stability, compatibil.

and other properties are being obtained for oxides, metals, and carbides

importance in this connection. For this work a special inductively-heai,

furnace and a metal-resistance furnace were designed and construct!]

Specimens may be heated in these furnaces at very low absolute atmosphe

pressures (as low as 5 x 10~^ mm of mercury at the beginning of a test) orl' a neutral gas in which oxygen is believed to make up less than 1 part in thi million. The behavior of these materials in combinations, when heated' temperatures between 800° and 2,500°C, is being evaluated by means'' X-ray diffraction techniques, chemical analysis, visual observation, and t study of their microstructure. For example, the fundamental phase eqf' libria have been investigated for four binary systems—UO2-AI2O3, U02-Be^^

UO.-MgO, and UO.-SiOo. J Ceramic Coatings for Electrical Uses ' Specialized ceramic coatings were developed to replace a scarce grade

mica in electronic components. Investigation revealed that unconvention,

alkali-free coatings were superior to commercial-type porcelain enami

when electrical insulation at elevated temperatures was required. Sim| lated service tests of ordnance components indicated that several of tl^ developed coatings could successfully replace mica for the intend^; application. i 44
erence of Porcelain Enamels

n effective ceramic or porcelain-enamel coating must adhere to the

jal it is designed to protect. Cobalt oxide effectively promotes ad- nce of porcelain enamel to iron, and for this reason has long been

( d to enamel ground (first) coats. Despite a great deal of research,

ver, the mechanisms by which cobalt oxide promotes adherence are not

i understood. Consequently the fundamental study of adherence of

pelain enamel ground coats to iron, sponsored by the National Advisory

jnmittee for Aeronautics, was continued throughout the year. An in- bigation of the correlation between roughness of interface and adherence

'tveen a cobalt-bearing porcelain enamel ground coat and iron revealed

|t roughness of interface is a necessary but not sufficient condition for the ielopment of good adherence. Further studies proved that the rough-

^5 contributing to adherence is produced during firing by selective corV ; ton of the iron and solution of iron oxide in the enamel. This selective ^^rosion was attributed to galvanic currents developed on contact between

' iron and metallic cobalt deposited from the enamel at the enamel-metal

srface. Previous experiments with radioactive cobalt had shown that

jjjjjtallic cobalt is precipitated from the enamel and deposited on the iron

>caf:;ring firing. Other experiments showed that galvanic corrosion can and

ts occur in an electrolyte of molten enamel during the short firing period,

ese data provided experimental evidence for support of the galvanic

ory of adherence.

^Another of the fundamental studies completed concerned the evolution

^'(igases during the firing of vitreous coatings on steel. The methods used

t^-:luded direct microscopic observation of bubble formation in the coating

eitiring firing, analysis with the mass spectrometer of gases entrapped in the nbd enamels, and the use of radioactive carbon to determine the source

iijj! carbonaceous gases entrapped in the enamel. The results showed that

|s principal gases evolved during the firing were carbon monoxide, carbon

pxide, and hydrogen. The blistering that is often observed in the early

jige of firing when vitreous coatings are applied to low-carbon steel was

jiund to be caused by evolution of the carbon gases formed by the oxidation

the carbon in the steel. Evidence was obtained that the hydrogen

rmed from the reaction between the dissolved water in the coating and

|ie hot iron base slowly diffuses into the coating as the firing continues. We of the hydrogen also diffuses into the metal. On fast cooling this kdrogen is expelled, causing bubbles to form in the coating at the interlace. It was found that practically all of the bubble structure in a nor-

[ally fired enamel is due to impurities in the clay mill addition. The

J lipurity is probably organic matter adsorbed on the clay particles.

|-iiermochemistry of Mineral Products

*^ Because of their favorable effects on the properties of concrete, pozzolans

' mtaining active silica are added to portland cement. There is a need

t 228268—53 4

i 45
for methods of test of portland-pozzolan cement to determine the am

of pozzolan which has been added as well as to determine the he

hydration of the product. The silica renders the blended cement

partially soluble in the calorimeter acid used in determining the he

solution of Portland cement. Techniques have been devised for d

mining the heat of partial solution of portland-pozzolan cements a hardened pastes, which permit the measurement of the heat of harde

of the blended cement. The fraction of the pozzolan which is insolub the calorimeter acid is relatively constant. The percentage of pozzolai

the blended cement can therefore be estimated from the weight of uij solved material remaining in the calorimeter at the end of the hea

solution determination. Measurements were made of the heat

hardening of mixtures related in composition to the magnesium oxychlc cements. It was found that, per gram of MgO, the heats of harde:

of all the mixtures were nearly the same and that about 80 percent of

total heat of hydration was evolved in the first 24 hours after mixing. ^ Cement

A study has been made of the factors which cause differences in sod

values in portland cement as determined by different flame photometers'*

method was adapted for determining alkalies in cement by the Beck^

flame photometer and recommended for adoption by ASTM Commr

C—1 . A proposed method for removing manganese from cement was stuc and improved so that it now gives consistently good removal as wel- correct calcium values following such removal. Studies have been n:' of the techniques involved in cement analysis in an effort to determine'

optimum conditions for ignition, precipitation, and washing of precipitj'

11. Building Technology

The need for economy in the construction, operation, and maintena'

of buildings has been the reason in recent years for the National Bur

of Standards to undertake a critical examination of old practices anc search for new practices based upon sound engineering principles. BeJ

full advantage can be taken of the kind of engineering approach that guided the rapid technological development of the electrical, automo'

and aircraft industries, the building profession must be supplied with

curate standards of measurement, new testing procedures, fundamental

gineering data and fundamental performance standards. No indust

organization has the facilities to obtain the needed fundamental engineei

data. The building profession, therefore, depends on the National Bur

of Standards as the principal laboratory of the Government for basic resea

in the fields of building materials, structures and equipment (exclud^

forest products which are studied by the Department of Agriculture Foj

Products Laboratory) . In addition, the armed services call on the Bun^

46
. analysis mass spectrometer used to determine the evolution of gases in vitreous

||iags on steel (p. 45).

4

j^^^evelop testing methods and to obtain technical information which are

^^jjnmediate value to them.

jjj^he fields of interest to the Bureau are those of structural engineering,

ygjjlding codes, safety engineering, fire protection, heating and air-condip]j|hing, and wall, floor, and roofing materials. Typical studies underway

j.[,lude resistance of concrete to impact, problems of the cracking of

g ..sonry, studies of the mechanism of fire-spread, performance evaluations

[jg;|various types of heating systems, measurement of the heat-transfer propdes of building materials, evaluation of air-conditioning and refrigeration

aipment, and development and evaluation of asphaltic materials, floor

'faces, and bituminous roofing. Assistance to federal, state, and municiid bodies on the development of adequate building codes and to industry

[ii)d the Federal Government on the development of safety standards is iptinuing.

Jiermal Conductivity

Measurements of the thermal conductivity of homogeneous materials used

building structures have been carried out for several years in the Bureau's

.arded hot-plate apparatus. Evaluation of the thermal conductance of

ilalls, floors, and roofs containing air spaces represents a special problem, in

iat the heat flow depends on the size of the specimen and its orientation:

^Dt only must large-scale test specimens be used, but arrangements must be

1 ade to allow rotation of the specimen around a horizontal axis, so that the inductance may be measured when the heat flow is horizontal, vertically

'Dward, or vertically downward. To eff'ect this, the Bureau developed the

ttatable hot-box apparatus, in which specimens 5 by 8 feet in size could

tested. Building elements of various types have been tested in the rotat- 47
able hot box, including those with highly-reflective air spaces such as ah

num surfaces, those with non-reflective air spaces, including surfaces pai;

with black asphalt paint, and those with air spaces of intermediate

flectivity such as silvercote insulation. Total radiation emissivity has 1 measured, thermal conductances obtained for various surface emissivi and a generalized relationship obtained to correlate the variables,

results should make possible the evaluation of the thermal-insulating q

;

ities of constructions, insulations, and paints used in floors, walls, and rc !j Resistance of Floor Coverings

Under sponsorship of the Office of the Chief of Engineers, Departn , of the Army, the effects of grease, oils, acids, alkalies, and bleaches \>j determined on 40 floor covering materials from 17 manufacturers,

materials tested included various linoleums, vinyl, rubber, asphalt, prir

enamel, and a few proprietary coverings. The softening effect of the i agents was determined by measuring the width of a scratch made witii sharp-edged tool on the surface of the flooring after exposure of 24 he

to the reagent. Most of the floor coverings were damaged somewhat

kerosene and dilute solutions of sodium hydroxide and acetic acid.

| general, vinyl floorings were oustanding in resistance to grease and c Some of the asphalt tiles described as "grease resistant" were softei appreciably by grease and oils in these tests. Cellular Concrete

i Cellular concretes are lightweight building materials weighing from

to 100 Ib/cu ft in which the reduction in density relative to conventioi concretes is accomplished by developing voids within the mix prior;

hardening. Cellular concretes have been produced as masonry units appreciable quantities in Sweden and Germany in recent years but hi received comparatively little development as structural materials in t; country.

The Bureau has conducted an exploratory study of a type of cellu^, concrete known as "foam" concrete in which, with the aid of foam stabil ing agents of the types used in fire protection and rapid agitation of t! component ingredients, a foamed mixture similar in texture to a st whipped cream is produced. By using lime or portland cement, a pozz! lanic material such as fly ash, and a foaming agent, and subjecting t mixture to high-pressure steam curing (100 to 150 psi), materials havij

relatively high strength to density ratios may be obtained. The use of : ash represents a potential economic advantage: it is a waste residue ' powdered coal burned in many power plants and is available in larj quantities at low cost. Foam concretes having compressive strengths I: 1000 to 2300 psi have been made at the Bureau in the density range 45

55 Ib/cu ft. The Bureau's concern with this material is to obtain ar evaluate data on its physical properties in order to establish its utility

various construction applications.

48
ajuftective Coatings for Concrete Masonry

laboratory and field survey of commercially available protective coatfor exterior concrete masonry surfaces was made at the request of the artment of the Army. The laboratory phase of the study included the rmination of spreading rate, water-vapor permeability, resistance to

er immersion, abrasion, and durability by accelerated testing. Data

e obtained on the resistance of some of the coatings to wind-driven rain on long-term outdoor weathering specimens prepared on four types of

ace. Age and condition of coatings were observed for a large number

tructures on the West Coast, in the Southwest, the Midwest, and the

nity of Washington, D. C, and problems were discussed with builders

distributors. One of the principal conclusions from this study was

t proprietary portland cement paints and paints made on the job from

jtland cement, when scrubbed into the outside surface of concrete maVy walls, give protection from leakage caused by wind-driven rain. The

{iition of sand to these cementitious paints levels the finish surface of

igh-textured concrete masonry and improves the durability and water

stance of the coating. Such coatings are preferred for use as base coats open-textured concrete masonry walls.

ei -;jndow Air-Conditioning Units

!fhe Bureau has undertaken a variety of projects concerned with the

jiluation of refrigeration and air-conditioning apparatus. Typical of

fse is the evaluation of several commercial %-hp window air-conditioning

\ts for the Department of the Army. A portable, 150-cubic-foot warease normally used for refrigerated storage served as a calorimeter. The

' ,; cooling capacity of each of the units was determined for various com- fiations of indoor and outdoor temperature, up to an outside temperature

||125° F. Air-circulating capacity of the evaporator and condenser fans f s measured and a determination of the maximum quantity of ventilating

ij introduced by the unit into the conditioned space through the fresh-air ^mper was made. The electrical circuitry, including motor-overload

otective devices, was tested under severe conditions.

tfjtdiant Glass Heating Panels

^Electrically powered radiant glass heating panels have been evaluated

|t/der various conditions of use in the NBS Test Bungalow. The tests,

feade with outdoor temperatures ranging from 0° to 32° F, showed that p vertical temperature differences in the living zone were moderately

j'v, comparing favorably with most other systems previously tested. The

brtical temperature variation was found to be essentially unaffected by

I e presence or absence of insulation in the walls and storm windows.

le average horizontal temperature variation between rooms was 2.5° F

:i less for all observations. I'Comparisons were made with forced warm-air heating using identical

j.tdoor temperatures and with indoor temperatures maintained the same

49
Left; resistance of various floor coverings to effects of grease, oils, alkalis, and j is determined by scratching exposed specimens with sharp tool (under the gram mark). Width of the scratch gives measure of resistance of various covei

to different reagents (p. 48). Right: concrete cylinder (bottom center) set u] impact testing with drop hammer (p. 48). I

at 30 in. above the floor. The radiant system was found to provide n

radiant energy than the forced warm-air heating system and more com

at the floor level. The panels were found to be able to resist ther shock such as rain water trickling down over the glass panel fror windowsill or cold water accidentally thrown on the panel. The 1 results indicate that electrically-heated radiant glass panels constituti satisfactory method of warming a basementless house from the standpc i of temperature variation in the vertical and horizontal directions, fl temperatures, and general comfort. Even with a house thoroughly \ sulated, however, electric heating can be expected to entail higher anrJ heating costs than would coal, oil, or gas in the same structure with li or no insulation because unit cost of electricity is greater than that of ot common fuels in most regions.

12. Applied Mathematics

The NBS mathematics laboratories were established in recognition the need for a centralized, national mathematical consulting and resea-i facility equipped with high-speed automatic machinery, capable of p.' viding analytical and computing services for other Government agenc; In this area the Bureau engages in basic mathematical research direc toward the better utilization of the new electronic computing machin'

and in addition acts as a service organization, particularly in the fields engineering statistics and quality control, for the Armed Forces, otl Government agencies, and industry.

Numerical Analysis

The study of large sets of simultaneous algebraic equations and

techniques for the inversion and iteration of matrices has been called i 50
; : problem of numerical mathematics. The Method of Conjugate

jiidients was investigated and appears to be a most attractive method

j [finding the eigenvalues of a matrix. During the year experimental

I jputations were undertaken in order to test the stability of the method

' igards round-off errors and related problems. Studies of the numerical

oration of differential equations were continued. This subject is imtant because of the large number of applied problems which are

jjhematically formulated in this manner. The Bureau is accumulating

' rge body of information concerning the feasibility of solving such

lems by means of large-scale computing machinery.

esearch in the mathematical theory of program planning is also one

he subjects which continued to receive the attention of the Bureau,

itjljarge amount of theoretical work was done on this subject, including

'^flpher development of criteria for the existence of solutions for systems

upjj^.inear inequalities and investigations of various geometrical aspects of problem of solving such large sets of linear inequalities.

^ number of computational experiments on this and on other problems

Djfp carried out. The goal of such investigations is to find practical

ni|Dbputational methods utilizing high-speed computing equipment. As a

filiiproduct of the program, the primality of Mersenne numbers was inEjiltigated and toward the end of the year a new prime, 2^^^^-l, was dis-

;| 'ered. This, the fifteenth perfect number, is by far the largest prime

jfcovered to date.

litistical Engineering

i The program in statistical engineering is concerned with the application

X| modern statistical inference to complex engineering experiments and

Ihpling problems and with the analysis of data arising in physical experi-

[fents. Advances in the field of experiment design have for the most part

m stimulated by the needs of experimenters in agriculture and biology.

ii;perimental arrangements that are successful in these fields often

I not applicable in the physical sciences. The NBS has thus developed

to new classes of experimental arrangements to meet needs of physical

entists, and these arrangements have found application in experimental

fograms in spectroscopy and temperature measurement at the Bureau.

llWork on stochastic processes and on the theory of extreme values was

IVried out. The Bureau is now engaged in preparing a bibliography and

Hide to statistical methodology literature. Basic research has been under-

'jken on distribution-free methods of statistical analysis and on properties

, characteristic functions. Perhaps the most important of the theoretical

idies being carried on by the Bureau is that relating to the development of theory of measurement. This research is basic to studies of the accuracy

id precision of measurement processes and is directly related to activities

t other sections of the Bureau concerned with establishment and mainte- mce of basic standards. 51
sit

loi

SWAC operated on a 40-hour week (p. 65). Ja Computation

In addition to performing computations requested by Federal agencL

NBS works continuously to create a stockpile of mathematical tables wJ; can be used to facilitate such computations. At the same time, an ef

is made to develop new or improved techniques for numerical computat; ^ particularly those adaptable to automatic computing machines, and to ti mathematicians in the application of numerical methods. During the the Bureau provided training in the programming and coding of probh

for solution on automatically sequenced, digital electronic computers, i consultant services on the applicability of such computers to specil

problems. j Essential contributions to the success of Atomic Energy Commission p grams were made. Computations required in many other military probk'

jp were handled, such as trajectories of various missiles, design of fire-cont equipment, and studies of explosions. Major contributions were also mj

in connection with work for the Office of the Air Comptroller. Programs

the deployment of aircraft of various types were computed, so that there n

be a proper balance between various activities of combat, reserve, and tra^

p[ ing. In this connection, computations concerning a model of the nation

^ economy, the so-called Emergency Model, have been completed. The co^ putation of Loran navigation tables was transferred to SEAC, at a cons

erable saving in time compared to the manual and punched-card computi,!

methods previously used. 13. Electronics

In electronics the Bureau carries out a broad and diversified progrg including both research and development. Research is directed towa' 52
iin basic phenomena and properties of materials of potential signifi-

- to electronics. Development covers not only the field of electronic

litry for the performance of new functions by electronic means but also proader phases of fabrication technology by which optimum engineering

tns for electronic equipments may be achieved. Emphasis has also been

\ed on the improvement of operational reliability of electronic equip-

[t by the development of new components and the application of new

trials and improved assembly techniques. This work is of particular

iortance to the military in the adaptation of electronic devices to extremes

ilimatic and operational surroundings. Much of the work is sponsored

the Department of Defense as well as by other Government agencies.

] luring the past year, the work in electronics consisted essentially of an

l^knsion and intensification of the various phases of the program already

lier way, including new components and new techniques ; the publication

li report providing complete information on the preparation and proples of the NBS Adhesive Tape Resistor over a range of resistances from

f^hms to 10 megohms; investigation of possible methods for prediction

I'ailure in electronic equipment; investigation of the functional behavior

tathodes and gases in electron tubes; development of testing evaluation

•cedures and test equipment for electron tubes ; development of specially 'ipose electron tubes; development of an improved cuvette recording

Hisitometer; the publication of a complete final report covering four in-

^ lamentation systems for the measuring of oil film thickness in journal

firings; the development of a vibration calibration instrument covering

range of 10 microinches to 10 mils over a frequency range of 20 to

{.000 cycles per second.

''|A.n increasing amount of technical attention was directed toward appli-

'tion engineering, particularly in the introduction to service of new

iuipment already developed by the Bureau. Examples of such work

:lude the automatic currency counting equipment developed for the

lireau of the Public Debt, Department of Treasury, and the automatic

'uperature monitor and the turbine rotor position indicators developed

't the Bureau of Ships, Department of the Navy.

;iadhesive Tape Resistor

ij Printed electronic circuits—in which components and wiring are supere'lposed directly on insulating bases—are being used increasingly because

5 ey are adaptable to mass production and facilitate miniaturization of

jiuipment. The major disadvantage, however, has been the difficulty of jcorporating satisfactory resistors in the circuits. This difficulty was

rgely overcome in 1951 by development of an adhesive tape resistor ethod, sponsored by the Navy Bureau of Aeronautics.

. In this technique, circuits are first printed in narrow metallic bands on

jisulating bases, leaving a small gap at each point where a resistance is •quired: one of the self-adhesive resistors is then cut from a strip and pressed

i
Instrument for detecting incipient failures of electronic equipment (p. 55] [t into position. Much better control of resistance values is possible tt eIo with previous printed resistor methods, and higher yields of accepta ;^ assemblies are assured. The new method thus appears to combine i; tb advantages of printed resistors and of separately manufactured resisto itii The NBS tape resistor was developed to withstand the high temperatu^ |)i of very compact equipment and operates satisfactorily at temperatures : ii; to 200° C; in other electrical characteristics it is similar to present film-ty

{ carbon resistors. During the past year improvements were made by ti ti development of a low-temperature curing process for the tape resistc ; permitting its use on nonceramic base material, and an extension of t; : range of values, which now covers from 100 ohms to 10 megohms in regu] p production. A reliable and reproducible set-up for the measurement

j resistor noise has been developed, primarily to assist the tape-resist

program although the equipment can be used on resistors of any type. ' ^ Miniaturization . Under sponsorship of the Navy Bureau of Aeronautics, the Burej

continued the development of techniques applicable to the subminiaturiz

tion of military airborne electronic equipment. Because of the importan^^

and wide usage of air-to-ground communication from 220 to 400 Mc, ar because of the unusual problems peculiar to those frequencies, miniatui

zation of an airborne transmitter-receiver in that range presents a difficu' task. Design and construction of such a transmitter-receiver was ;' progress during 1952. The set will have no dimension larger than 24 inch^l 54
will be made up of individual plug-in assemblies. Also carried out

j tug the year was the redesign and miniaturization of an airborne radar

ilk^hich has been selected by the Navy as standard equipment for a new

of aircraft. jtronic Failure Prediction

^nce most types of electronic equipment failure are preceded by gradual

srioration, the possibility exists that these deteriorations can be detected

predicted. Under sponsorship of the Office of Naval Research, the

!|eau has undertaken to develop equipment along this line. For ship- ne or land equipment the additional circuits required for such predicting

lipment may be completely contained, but in airborne units an attach- device would be more practical. In any case the additional circuits

. components must not adversely affect the over-all reliability. During

I' year cycling tests were conducted which showed that a large precentage

failures are of a predictable nature. Refinements and extensions of procedures were made and construction of an automatic testing device

; begun. veue Densitometer

''p\.t the request of the Department of Cardio-Respiratory Diseases of the

I 'Tiy Medical Center Graduate School^ the Bureau has undertaken the

ttp/elopment of special instruments to assist with their research programs,

sjiiie development of this program is the Recording Cuvette Densitometer,

f ich provides a method of making a continuous record of the rate of

!|lition of dye in the heart chambers by observation of blood flow from a

itrripheral artery. From this record calculations can be made to yield the

(cdiac output. The NBS Cuvette Densitometer consists of two sections:

]lp photoelectric pickup unit and the power unit. The photoelectric

i Hit is small and compact and can be conveniently located near the patient.

die power unit is line-operated, eliminating the necessity for batteries. le system has a high order of stability and absence of fatigue effects in

je photocell.

1 Film Thickness Indicators In studies of engines and engine lubricants, it is often desirable to measure

iarances between shafts and sleeve- or journal-type bearings during operain. It is usually difficult to obtain such measurements without affecting e operation, particularly at high speeds. A method developed at the NBS

|jr the Navy Bureau of Ships offers a satisfactory solution of the problem.

||ne heart of the new system is a mutual-inductance type of electrical dis- ^nce-measuring element; variation of the distance of the rotating shaft bm two small fixed coils results in a readily measurable variation in the

^jupling between the coils. Three successful variations of the device were

|iveloped. The models differ in the type and number of probes used, in

^'nsitivity, in suitability for measuring vibratory conditions, and in type of

iLdicating device. A cathode-ray tube is used with one model to provide a55
Probes of oil film thickness indicator (p. 5 5) are mounted at shaft entrance

j sleeve-type bearing. Cathode-ray tube (dial face) gives clearance between the s and the bearing. (Photo courtesy of U. S. Department of the Navy.)

continuous picture of shaft displacement; the other models give dista: indications on a dial or meter. Steam Turbine Rotor Position Indicator In modern marine turbines^ it has become desirable to have an ex knowledge of the clearance between stationary and moving parts. For t purpose the Navy Bureau of Ships requested noncontacting electrical p

cision indication devices to record these clearances. NBS first develod

shipboard installations which made these measurements external to 1 turbine. The next phase of the development was to make these measu

ments inside the turbine. Instrumentation has been completed and . stalled on an experimental turbine at the Naval Boiler and Turbine Labo:

tory. This equipment has 13 points of measurement, the majority bei

inside the turbine. It is expected that information derived from this inst lation will be of assistance in turbine design. Of particular interest is t correlation between internal and external expansion measurements. Asresult, data from external measurements alone may be used with confiden

as to inside-turbine clearance conditions. 1 Vibration Calibrator

The Navy Bureau of Ships desired an instrumentation system to assist , calibrating simple vibration pickups, thereby eliminating the tedious ta

of individual calibration of each pickup. At the same time, it has bet

difficult to find standards for measuring high-frequency vibrations when tl components are under test for such characteristics as noise, microphonic

56
rtability. To provide a suitable method for both of these fields of measent, an instrument based on mutual-inductance micrometer techniques

developed by NBS for the calibration of vibration pickups. The in- jment measures vibrations in the amplitude range of 0.00001 inch to

[ inch over a frequency range of 20 to 10,000 cycles per second and with

[accuracy of 5%. The equipment is composed of two units, the probe

k and the electronic chassis. The probe, less than one inch in diameter,

i tains the mutual-inductance transducer. Provision is made for obserion of the waveform on a cathode-ray oscilloscope.

ible Gas Clean-Up in Electron Tubes

iillectron tubes filled with a noble gas have a distinct advantage over

Ise filled with a metallic vapor because the gas density is relatively unafted by temperature changes and gas-filled tubes have rather uniform

2trical characteristics over wide temperature ranges. This fact would

I

ike gas-filled tubes preferable in many applications except that the gas

ids to disappear during operation of the tube. If the factors which de- mine the rate of clean-up for each of various combinations of metal and

icffii; were better understood, tubes might be designed so as to minimize this

3Ct. The Bureau has made a study of the clean-up of helium gas in a

jcharge tube with two additional gas-metal systems : nickel in helium and

•lybdenum in helium. The metals were in the form of cylindrical-type

obes. Two significant advances were made. It was observed that the

|an-up effect due to ion impact is time-dependent, and measurements were

!)dified to take this fact into account. It was also observed that proX3}iunced sputtering was present with each of the gas-metal combinations

tjl^ntioned above, and this afforded an opportunity to make some measureptents on the extent of clean-up due to sputtering.

14. Radio Propagation

I'The National Bureau of Standards Central Radio Propagation Laboraserves as the primary agency of the Government for research in radio

iiiave propagation and for the centralization and coordination of informa- mn in this field. The laboratory is also responsible for the development

jjid custody of the national primary standards for electrical quantities at

;bj'tdio frequencies. Comprehensive programs are undertaken in radio physics

jnad associated geophysical phenomena of the upper atmosphere and the

jlDposphere. Extensive laboratory studies are also under way dealing with

'"operties of matter at radio and microwave frequencies and the development of techniques for precise measurement of electric quantities in this

1 gion. In addition to such research activities, the Bureau does a large

ifnount of advisory and consulting work on radio for other agencies of the

P'iOvernment such as the Department of Defense, the Civil Aeronautics AdjLinistration, and the Federal Communications Commission, and partici5|ates in an advisory capacity to the State Department in the international 57
58
jio conferences. The work in radio propagation is divided into four

inches: ionospheric research, regular propagation services, systems re- tch, and measurement standards.

jrhe Ionospheric Research Laboratory conducts basic research on the

|:ure of the upper atmosphere and its abiUty to reflect radio waves. The

treau uses a widely separated network of 1 7 ionospheric sounding stations [ending over the American continents and the Pacific area. Data supped by these observatories provide basic material for research and for deitaiining frequencies to be used in long-distance radio communication,

! addition, a permanent radio propagation field station at Sterling, Va.,

Id a number of temporary field stations are operated for performance of xial experiments. Because of the important influence of extraterrestrial

ects on ionospheric phenomena, solar and cosmic phenomena are studied,

lese include radio waves emitted by the sun and other celestial bodies,

liich also aflford a new means for exploration of the universe. The Regular Services Section is responsible for the centralizing and

ordinating of ionospheric data, predictions, and advisory services. To

complish this, data from ionospheric stations are received and analyzed

jid the best frequencies for radio communication predicted. This informam is disseminated by means of regular monthly publications of the data and

mail, telegram, and telephone to Government and commercial users and

cooperating laboratories both in this country and abroad.

The Systems Research Laboratory applies radio propagation informa- on to the practical problems of radio communication with particular conIderation to the advantages and limitations of the types of communication

stems involved. It also conducts research on the propagation aspects of

(larious radio systems such as FM and TV, on radio noise, types of modula- on systems, and practical improvements of radio predictions and radio

lavigation systems.

The Measurements Standards Laboratory conducts research on standIrds and methods of measuring electrical quantities at all radio frequencies,

fhe principal function of this laboratory is the development and mainteiance of primary standards of electrical quantities at all radio frequencies,

including time and frequency standards which are broadcast continuously

y the Bureau's radio station WWV at Beltsville, Maryland, and by an

xperimental station WWVH in Hawaii. The need, usefulness and scope

f these developments of standards, instruments, and techniques of radio- requency measurement have been increasing steadily.

,1gladio Astronomy

^ Cosmic and solar radio waves reaching the earth from outer space limit "he minimum usable signal levels for FM broadcasting, television, and

:ommunication and radio navigation services in the very-high-frequency

ange. In recent years, the techniques of radio astronomy have been deiv'eloped for receiving and analyzing these radiations from outer space. This

I 59
had made it possible to obtain information about the positions of ste bodies and the matter in interstellar space that could not be obtained \ an optical telescope.

The program of calculations attempting to account for the enhan

levels of solar radio signals by means of plasma oscillations was contim

Some progress has also been made in the development of a theory for propagation of shock waves in an ionized atmosphere with superpc

magnetic field. The theory indicates a departure from a Maxwellian vel ity distribution on the part of the electrons. It is hoped to apply the res to explain the fine structure of solar radio bursts and the anomalies in exc

tion and temperature distribution present in the solar chromosphere.

Ionospheric Winds

Monthly ionospheric winds measurements utilizing fading at 2.3 Mc w

continued on an intensified scale. The intensified program was made p|

sible by a device which automatically senses and records phase differen in the fading of signals received on separate antennas. A study compar

magnetic field variations with wind speed and direction variations me

ured in nearby localities was undertaken to ascertain to what extent lo wind variations may be correlated with local magnetic variations, l theory of correlation in the fading radio field was studied with a view

ward ascertaining the feasibility of measuring the true wind speed us; only simultaneous measurements of the field. Plans were completed

acquire a special low-frequency correlator capable of making a comply

auto- and cross-correlation analysis of fading data. Low-Frequency Ionosphere Recorder

The Bureau has operated sweep recorders in the high frequency rar from 2 to 25 Mc for a number of years to investigate the upper regions ' the ionosphere. Until recently the complexities involved in designing a 1(^ frequency recorder seemed insurmountable. During 1952 NBS complet'

and successfully operated a multifrequency, sweep-frequency, ionosphe

recorder covering essentially 50 kc to 1 100 kc in less than one minute. Tl was the first time that such a recorder had ever been operated. Its coi pletion meant the overcoming of three major obstacles : a large operatin

frequency ratio, antenna ringing, and loss of effective output due to anteni

inefficiency. The transmitter operates near the million watt level. The recorder furnished daylight information about the E layer nev

before available. A remarkable phenomenon noted on continuous motio

picture records of repeated sweeps was the formation of the regular

layer at sunrise. It appeared to grow out of the night F2 layer, droppii

in virtual height and developing a cusp within a period of four minute

Details of the F2 extraordinary reflections at frequencies below the gyr

frequency were visible as were details of certain types of stratification. 60
i.nsmitter assembly of new ^^-million-watt low-frequency ionosphere recorder

'60). Power supply (left), low level amplifiers and pulse generator (middle),

1.1 amplifier (right).

jdio Navigation

ji\ large portion of the low-frequency spectrum is allocated to radio navi-

,:ion systems. To improve the effectiveness of such systems, much basic

ifearch was done on propagation. The most significant achievement of

li past year is a theoretical determination of the total phase-change of a

iio wave propagated over a spherical earth. Accurate methods for comting corrections to take into account the effect of mountainous terrain d changes in the atmospheric refractive index were also developed. These

jioretical calculations were checked by actual measurement and show an

' provement in accuracy of at least one order of magnitude over previous

^^oretical calculations.

I |Ddulation Studies

(Because of the scarcity of space in the radio-frequency spectrum and the

cessity for more reliable communications, a study of the efficiency of

, rious types of modulation and methods of communicating over radio

i-ths has been undertaken. The frequency spectra, including phase inforjation, were obtained for a large number of modulating wave forms apied as amplitude, frequency, or multiple modulation to a carrier fre- lency. The bandwidths necessary for satisfactory system operation were

228268—53 5 61
obtained for some specific systems, such as frequency shift keying. In , j !^ tion, simplified formulas were derived for the interference produced • number of waveforms employed in both AM and FM systems. Sp

' formulas were derived for the interference bandwidth at any specified for frequency shift teletype, frequency shift facsimile, and sub-carriei: quency shift facsimile. Other work includes a review of the condi

:

necessary for high-frequency broadcast reception and the derivation

' formula for calculating the noise figure of an FM receiver or the mini] i satisfactory input carrier for a given output signal-to-noise ratio. New laboratory facilities were established for the modulation studies

linear modulator which is capable of simultaneous or independent ar 1

1

tude and frequency modulation was constructed. Initial operation o: !

i equipment in conjunction with a panoramic analyzer showed good ai j ment with the spectrum calculations. A pulse generator capable of

erating arbitrary pulse forms of finite length was completed for use in st' ing optimum pulse shapes and filter shapes for various applications.

VHF Propagation Research ' Research was continued on the problem of allocation of radio-frequchannels to very-high-frequency communication and broadcasting serv^ Experimental studies were used to determine the effects of irregulai, in the terrain and of meteorological variations in the lower atmospt

In addition to the tropospheric field-strength recordings made by

National Bureau of Standards, continuous field-strength data for t^ie ei, year were obtained on fifty-three paths by seven contracting group,

strategic locations throughout the United States. Considerable progress was made in the development of two diffe j theories of very-high-frequency radio propagation which are intende(

explain the high field strengths observed at great distances beyond * horizon. One theory explains the high observed field strengths on the I \ of partial reflections occurring in a horizontally homogeneous atmosph

while the other theory attacks the problem from the standpoint of scat ing from isotropic atmospheric inhomogeneities. Further work, both

perimental and theoretical, is required before conclusions can be drawn

Terrain Effects on VHF Propagation

In cooperation with the United States Army Signal Corps, a mobile ic i field-strength laboratory was used to study the directivity of directic antennas over irregular terrain, at frequencies from 49 to 460 I Throughout the frequency range it was found that considerable varial

in apparent antenna radiation pattern existed due to variations in configuration in the intervening terrain. Theoretical studies were madt 3 determine optimum frequencies for short-distance communications us ^ low-powered portable equipment over irregular terrain paths.

62
Standards

improved calorimeter for the precise, absolute measurement of micropower was designed and constructed. This instrument measures

)wave power at frequencies in the neighborhood of 9000 Mc at a

of a few milliwatts. The techniques are not intended to supplant

^"^jentional microwave power-measuring methods but rather to enable

'/'rate caHbration of secondary power-standards of various types. The

%ed accuracy of better than one percent appears more than adequate

I [lost present-day requirements.

^^dance Measurements and Standards

\rther work was done on the development of impedance standards, in- king several types of impedance standards for waveguides. These standl^erminations to waveguides or coaxial lines have known reflection prop-

"^fls and are very useful in the microwave laboratory. One type consists

p. accurately matched and calibrated attenuator terminated by a shortplate. Designs for waveguide discontinuities that are amenable to pre-

: [mechanical construction and to theoretical calculation were selected,

I calculations were partly completed,

^^'j technique for combining known waveguide impedances by means of '^eguide junctions to produce new known impedances was investigated

'^er thoroughly for the case of H-plane T-junctions. Comparison tech-

' les, enabling comparison of unknown with known impedances which

^ "magic-T" junctions, were developed to a point considered adequate

^4he present. The resonant-line (Chipman) technique of impedance

purement was studied in both coaxial and waveguide versions.

^J^io Interference and Noise Measurement

I ( program was initiated which, if successful, will lead to the establishtdiit of a complete calibration servdce at NBS for radio interference meters,

^iiuding those employing rod-type antennas. The design and construction

tt. detector to determine the rms, peak, and quasipeak, or average value

ihe interference over any time inter\^al up to several seconds were comjled. Preliminary investigation indicated the problem of interference

r.er standardization to be both urgent and of very large proportions.

|luation of a standard noise source usable up to 4.2 Mc was completed

}h very good agreement (better than 0.5%) between experimental and

Horetical constants. Work was under way on sources usable up to 30 Mc.

|imic Standards of Frequency and Time

^ecause of fluctuations and secular changes in the length of the solar

\, unchanging standards of frequency and time are needed by science,

^jce the first atomic clock, based on the constant natural frequency asso-

^^ied with the vibration of atoms in the ammonia molecule, was announced

if NBS in 1949, an intensified program has been carried on which now

63
comprises the investigation of four different types of atomic clocks. l\ trum lines which are both very intense and sharp are required in this < to secure an ultimate standard. One of the most troublesome prol [ found in the ammonia clock has been a Doppler broadening of the spec

line, and much study has been devoted to the possible kinds of spec

lines that could be best employed, the atomic systems involved in obta

such spectrum lines, and the methods of excitation of these systems.

The most promising results have been obtained so far through the u magnetic resonance techniques employing atomic beams. The work or method (considered to have the highest potential accuracy) was b

shortly after the initial work on the ammonia clock. The equipmen now been completed and preliminary work done on the excitation o; spectrum line in an atomic beam using cesium. With this equipme

spectrum line having the sharpest resonance ever obtained has been exc The measurements have furnished direct evidence indicating the possil

;

of measurements to better than a part in 10 billion—an accuracy coj' erably greater than that achieved in the measurement of optical waveler ^ and about 100 times greater than present astronomical frequency and I standards.

15. Automatic Electronic Computers; Information Processi

SEAC

During the past year SEAC (National Bureau of Standards Eastern A ' matic Computer) has continued to turn in an excellent record of perfc! ance in its dual use for mathematical computations and for engineei

design studies. The pressure for its services has made it necessary to ope

throughout the year on a basis of 24 hours a day, 7 days a week. A toU

over 50 different problem types have been handled on the machine. | response to an urgent request from the Atomic Energ)- Commission, ( two-thirds of the machine's time was made available for several mon

and this AEC work is now continuing at the level of about one-thirc the total time. \ In its role as an experimental tool, SEAC has been used to test improinput-output devices and memory units. A magnetic tape device has b

developed which permits rapid starting and stopping of the tape by elimir ing the inertia associated with ordinary reels. In this device the tap] stored in loose folds in a two-dimensional bin. To start the tape it is c i necessary to accelerate a few feet of the tape material itself, and not

entire reel. These devices have been tested and have been put into regi

operation in problem solutions. Because of the bulk of the bins in wh^

the magnetic tape is stored, these units are not readily adaptable to load,

and unloading with ease. A separate unit has been developed which ma.

use of spools of magnetic wire assembled into a plug-in cartridge. T

cartridge does not permit the rapid accelerations of the reel-less magnt

64
.Ol(

tnits, but it is much more rapid and convenient for loading and ung. It permits a new problem to be inserted into the machine in a of a few seconds, and results may be removed equally rapidly. Equipalso has been constructed and is in regular use which takes results ded on this magnetic wire and prepares, independently of the central

line, a printed copy for punched cards. second experimental use of the SEAC system has been in the testing

h electrostatic memory unit. This type of memory holds considerable

jiise in the design of future machines because of the rapidity with which

possible to obtain information from it or write new information into

[t is, however, subject to certain circuit sensitivities which require very

[ul design if the necessary order of reliability is to be achieved for comr or data-processing use. A full prototype memory of this design has I

attached to SEAC and tests made on it show considerable promise for Vuture. It has already been experimentally used in the solution of some

'''' 'jhematical problems.

\cer

^ Ker 600 hours of useful computing time was obtained on SWAG (Naal Bureau of Standards Western Automatic Computer) , and the useful

rational rate by the end of the year was approximately 40 hours per

^jk. A punched-card input was installed, permitting the memory to be

fled in 6 seconds in contrast to the 5 minutes required by teletype tape,

j. number of studies in pure mathematics were carried out using SWAC.

, example, the primality of Mersenne numbers was investigated, and

ard the end of the year a new prime, 2^^^^— 1, was discovered. This is

»|;; largest prime number discovered in mathematics. (See page 65).

I Computers

k

jihe first new computer is the STATAC-SCOOP, which is a serio-parallel

Lchine of very high speed, being designed for use with a parallel electroic memory and intended primarily for application to large-scale coming problems such as the SCOOP project of the Office of Air Comp-

^ Her, USAF. Since actual construction is dependent on realization of a

joh-performance parallel electrostatic memory, the major effort has been

i(j/oted to continuation of the analysis relating to the so-called triangular

jiidel type operations. Many of the equipment design features are being

(jsd out in the construction of DYSEAC, particularly the new package

iistruction. jThe second new computer, DYSEAC, is a full-scale general-purpose

^ial machine operating at a 1 -megacycle repetition rate and containing

^ierial acoustic delay-line memory of at least 500 words. It differs from

fiAC in the following particulars : ( 1

) it contains an expanded repertoire

^ arithmetic operations ; ( 2

) it contains provisions for annexing a greater

^dety of external storage and input-output devices; and (3) it is capable

f
SEAC operates on a 24.hour day, 7 days a week (p. 64). New reel-less magi

tape external memory devices (right and center) which have unusually fast a. i time (p. 64). Insert: for loading and unloading the computer very rat » magnetic wire cartridges were installed (p. 64). I of carrying out automatically, in an integrated fashion, concurrent op

tions involving high-speed input-output and processing of data (e. g., it be capable of receiving nonsynchronous data from telemetering sourcf the same time that it is carrying out a complex program of data-processii

The last feature will make the new computer considerably more fleJ and powerful than SEAC for complex data-handling operations. Bee; the high-speed memory of the computer is almost immediately accessibl other units of the data-handling network, the computer can be used

storage reservoir which can be shared among the other units of the work and which can be interrogated (or recorded in) by them indepf

ently, without disrupting the course of the internal data-processing ] gram. Final system specifications were adopted, and work is under wa)|

the preparation of detailed plans required for construction and assem Technical Services

The Bureau also acts in an advisory and consulting capacity for ot Government agencies interested in acquiring automatic computers. Du]

1952 the Bureau accepted two computers and monitored their installat l k One was delivered to the Office of Air Comptroller, the other to the Ai

66
I Service. Computer design and procurement for the Air Force Missile

I Center and Willow Run Research Center (University of Michigan)

[ continued as cooperative efforts. The Bureau is also technical repreiiative for the Bureau of the Census, which operates a data processing

Ihine. The Bureau has continued to serve as a clearing house for injiation on the potential applications of electronic digital-computer techkes both for scientific problems and for the processing of business types

lata. NBS representatives have met with officials of many Government

[icies and industry.

Irmation Storage

I'he storage of information on punchcards, film, magnetic wire and tape

'icome into wide use in the last ten years. A basic problem in such storage

bms is the speed with which the stored information can be selected. Anb to this and other problems, such as the reduction in size of the equipIt and the storage medium, are being sought by the Bureau. Part of the k is related to the NBS program on electronic computers, and some work

eing done to solve particular problems for other government agencies.

!i special paper punch is being completed for use in connection with the

Did Microfilm Selector now located in the library of the Department of

^culture. This punch will make it possible for an operator to prepare

Hal perforated cards by merely pushing keys similar to those on adding

chines. In addition, a light-box is being provided on which these cards

to be mounted for photographing numerical subject codes alongside the

J I profilm image of a page of printed matter. This is the second part of an

I provement program in connection with the Rapid Microfilm Selector.

I' A punchcard-sorting machine, which operates on an entirely new prinl^Ae, is being completed for the Census Bureau. In this machine the cards

i ll carried by an endless belt. Each card is accompanied by a set of twof-tition cams which can be arranged to designate a pocket into which the

^tifd is to fall. This makes possible the construction of punchcard-sorting

f

^chines with unlimited numbers of pockets. Present sorting machines are

liited to about 40 pockets at the very most.

(A Notched-Disc Memory Device developed by the Bureau is in process of

^instruction by a contractor. This model will be able to store about as

fluch information as a quarter million conventional punchcards, even iough it is only a one-quadrant model. A full-circle machine could handle

im times this information. Access to any part of the stored information

I quires only a small fraction of a second.

l|f: 16. Basiclnstrumentation

Since its founding, the National Bureau of Standards has carried on a

ril rge amount of research in instrumentation. However, in order to take full Ivantage of the Bureau's facilities and competence in the general field of

hysical measurements and to bring into play the ideas and developments

i 67
Left: electron interferometer (circled) installed between the electron gun and objective lens of a conventional electron microscope. Riehf close-un of electron interferometer (p. 68).

originating in all technical fields, a coordinated program of broad scope v needed. The NBS Office of Basic Instrumentation was established in 19 for this purpose, with the cooperation of the Department of Defense and t Atomic Energy Commission. Functions include general correlation of B

reau projects in basic instrumentation, maintenance of liaison with sponsc ing agencies, arranging for cooperative work on special problems, continu. survey of instrumentation work in progress at NBS laboratories, arrangi]^ for the testing and evaluation of new instrument developments, and stimuli ing theoretical and experimental studies of original ideas for improved

" novel means of measurement. Because instrumentation cuts across all lin ol technical activity and the specific projects under the general program a

carried on in many of the existing divisions of the Bureau, the Office Basic Instrumentation was estabHshed as a part of the Director's Offic The following projects represent some of the efforts of this office. Electron Interferometer

The concept of using lamellar crystals for splitting an electron beam suf gested the possibility of this instrument. Theoretical and design studies cor firmed the soundness of the proposed method, and an instrument has bee

constructed. This instrument, an analogue to the classical optical interferometer, . expected to throw new light on the nature of the electron by providing means of measuring the length of the wave train that modern theory assoc.- ates with an electron. This knowledge can also be expected to give rise t a better understanding of the process of electron emission, the phenomen

on which all of electronics is based. Moreover, since electrons of an energ

68
imonlv used in electron optics liave a wavelength one ten-thousandth of

t of visible light, an electron interferometer provides a basis for the isurement of length down to atomic dimensions.

ise-Free Instrument Cable

ipurious electrical signals or "noise voltages" present a problem in many

es of instrumentation work where instrument cables are subjected to

;:hanical forces. They interfere with measurements of pressure in under-

:er explosion and air-blast research and with determination of accelera1 in shock and vibration studies. They also adversely affect the perform-

:e of crystal-type microphones, hearing aids, and phonograph pickups

i many other high-impedance devices in the fields of communication,

asurement, and control. Until now, the mechanism of the noise genera1 has not been well understood and has been assumed to be somehow

ited to piezoelectric or converse electrostrictive effects, changes in the

-trical constants of the cable, or separation of electrical charges by

::tion. Laboratory ^vork in connection with piezoelectric-type accelerometers has

to the development of a "noise-free" shielded instrument cable, in which

J spurious electrical signals arising from mechanical motion of the cable

[i reduced by a factor of 500 or more relative to ordinary cables of similar "nensions and flexibility. This development appears to have rather wide

j plication in instrumentation problems, particularly those associated with

essure, vibration, and shock measurements.

'agnetostriction Magnetometer

Laboratory work in exploring possible instrumentation and control ap-

'ications utilizing the magnetostrictive sensitivity of certain materials has

dicated that one promising application of this phenomenon is its use in a

nsitive magnetometer. Preliminary^ tests show that detection of changes

the magnetic field of the order of 3 x 10"^ oersted (one-milHonth of the

irth's magnetic field) and the selection of the best-suited magnetic material

.ay further increase the sensitivity. It is expected that random changes in

le earth's magnetic field will come into the range of measurements well

store the ultimate sensitivity is reached; and the instrumentation may then

I- used to study these changes. It appears possible that two of the magnetorictive rods, set up so as to cancel these fluctuations, will allow significant

leasurements to be made even below this range. 'ulsed-Voltage Photomultiplier

Study of such light-emitting phenomena as those connected with single

,uclear disintegrations require light-sensitive elements having resolving

'imes of the order of 1 millimicrosecond. Ordinary techniques using photo-

^'lectric cells are not capable of this resolution. Efforts to improve the per- ormance of photomultiplier tubes have resulted in the development of echniques for intermittent tube operation in which relatively high tube

69
voltages and currents are used, with a resulting increase in tube periormai I greater than an order of magnitude. Experimental work presently un(

way, in which radio frequency voltages are applied to the tube elemerl shows promise of equal improvement, with substantial simplification

equipment. , Mutual Inductance Transducer ! The variation in mutual inductance between two coils in proximity tc

!

conducting surface has been utilized as the principle of operation for a nui ber of instruments. These devices include instruments for measuring t thickness of electrodeposited metal coatings, insulating coatings on metal a: bearing oil films, the separation of metal surfaces, and the amplitude

mechanical vibrations. These instruments have good stability, high sen

tivity, and are particularly adapted to measurements where optical or ir chanical access is not available. It appears that an additional possil

application of the principle lies in the measurement of the condition i ^ alloys by measuring the electrical properties of the metal, for such purpos pi as hardness testing. ( See also p. 55.)

17. Calibration, Testing and Standard Samples ; A direct result of the Bureau's custody of the Nation's basic physic

standards is its program of calibration, testing, and standard samples.

The NBS calibration service is of great benefit to industry and prival

laboratories. Thousands of instruments are yearly sent to the Bureau f( calibration. Some of these are standard laboratory devices and some a.:' master instruments used by industry to calibrate production tools. Standai

samples are materials that are certified for chemical composition or for son

physical or chemical property, such as heat of combustion, melting point, ( index of refraction. Standard samples of steels help to control the qualil oi the steel industry's output. Primary chemical standards and metals wit

certified melting points make possible uniform measurements of heat an- temperature in the same way that standard weights provide uniformity c measure in buying and selling. Standard pigments define the colors c paints. A large variety of hydrocarbons, supplied as single substances cf high purity, calibrate the instruments that control the composition of mote,

gasolines, aviation fuels, and synthetic rubber. The list of standard sample

issued by NBS now includes about 500 materials.

" The Bureau's testing activities are mainly directed toward ensuring tha materials purchased by the Government conform to specifications. A mul

titude of diverse items are tested and the results, in many cases, eventuall- save the Government millions of dollars. In the course of this work th( Bureau also develops new instruments, new methods of measurement, anc much technical data on the properties of materials. J During the year over 300,000 tests and calibrations were performed fo:' other Government agencies and the public. In addition, about 33,000

70
^-^ ferd samples were prepared and distributed. Typical services of this jincluded the sample-testing of over 200,000 clinical thermometers pur-

|d by the Government, the life-testing of about 4,500 light bulbs (a samof nearly 7,000,000 purchased by the Government this year), the cali- m of approximately 8,900 gage blocks, over 860 measurements of radon

^ath samples, the testing of 277 ores and sludges for radium content, the

ration of more than 700 water-current meters, and the calibration of

'* >|)0 capacity-measuring devices,

'pre than 15,800,000 barrels of cement were sample-tested during the

i The increase of approximately 3,300,000 barrels over the previous

^ 'jwas largely due to increased Federal construction. The tests, consisting

lysical and chemical analyses, were carried out at four separate field hns established for this purpose as well as at the central laboratory in

^jhington. Closely related to this work is the program of the Cement

'irence Laboratory, which inspects the apparatus and test methods of

!3nt-testing laboratories. This laboratory is located at NBS and is jointly

iorted by the Government and the American Society for Testing MateL The Public Roads Administration contributes to the financial supI of the project and requires that laboratories testing cement for Federalorojects must be inspected regularly by the Reference Laboratory,

br many years, all radium preparations sold in the United States have

]i tested and certified by the Bureau. During the year 1,808 tests of

ierials such as radium, mesothorium, and cobalt 60 were made for the crnment and private concerns. Over 1,300 radioactive standards were

jtibuted, reflecting the constantly increasing demand throughout the

in try for this service by the Bureau. These included radium gamma-ray

idards, alpha-ray standards, radium D + E standards, radioactive iodine,

ioactive phosphorus, radioactive carbon, radioactive cobalt, radon stand-

's, and rock samples. To protect the health and safety of workers in

fj^pations involving the handling or processing of radium, the Bureau

ntains careful check over the quantity of radium ingested by such

kers and over the quantity of radon present in their working areas.

jctricity

^kandard apparatus was tested for manufacturers, electric power comlies. State public utility commissions, university laboratories and private

J:ing laboratories as well as for many agencies of the Federal Government

is work involved over 20,000 separate exact determinations. Qualifica- n tests of dry cells and batteries were conducted. Started in 1924, these

ts have provided a continuous record of the quality of dry cells and baties manufactured in the United States over a period of 28 years, except a brief interruption during the war. The results of these tests have been

^nished to all interested Government agencies and have been utilized in janection with purchases of dry cells and batteries for the Government.

71
Using the new NBS vibration calibrator (p. 56) to calibrate a vibration pi, ot the accelerometer type. ^

Optics and Metrology

Approximately 1,160 standards were calibrated in photometry and cc imetry. These included incandescent, fluorescent, and mercury lamp stc ards of intensity, flux, and color; standards for checking the photome

scale and the 100-percent reflectance curve for spectrophotometers;

glass or vitreous enamel standards of color, reflectance, transmittance, oj

ity, and gloss. Samples from about 7,000,000 lamps were inspected

4,567 lamps were life tested. These included incandescent, fluorescent,

,

photoflash lamps. Those rejected on life test represented 2.0 percen- those accepted on initial inspection. Over 200 cameras and photograp

lenses, chiefly for photogrammetric use, were calibrated; 450 refractive in samples and various optical instruments or optical systems were tested. A total of approximately 1,800 NBS Microcopy Resolution Test Ch;

for use in testing microcopying camera and film combinations were issu The following tests relating to length were made: 10 length standards, i steel tapes, 96 invar base-line tapes, 373 sieves, 2,384 haemacytometer cL

bers, 16,100 cover glasses, 163 leveling rods, 9,158 precision gage blocks, ^ gages, 1,584 instruments and standardized instrument parts, and l,f thread measuring wires. Heat and Power

A total of 2,657 liquid-in-glass thermometers, 85 resistance thermometf^

and 404 thermocouples and thermocouple materials were calibrated. T

number of clinical thermometers tested was 41,499; 20,498 of these rep'

sented a sampling of over 204,000 thermometers purchased by the Vetera

Administration and the U. S. Public Health Service. Tests and caHbratic were made of special types of thermometers and thermometric devic

Fifty-six viscometers were tested or inspected, and 691 standard viscos' 72
les were supplied to other laboratories for use in the calibration of

meters. Calibration tests were made on four hydrocarbon samples in- d for use as reference fuels in knock rating. Seventy-nine fuels and

;antSj fifty-seven miscellaneous samples^ and fifteen oil filter cartridges

tested for compliance with Government specifications. Automobile

ine economizers, fuel and oil additives, and other automotive devices

jmaterials were tested or inspected for the Federal Trade Commission

(the Post Office Department. Other automotive products tested for rnment agencies included an armored car, a muffler, and seven motor

ij; speed governors. Twenty-two nonroutinc tests on aircraft electrical

liork equipment were conducted for the Bureau of Aeronautics, Departr of the Navy.

jnic and Radiation Physics

iie cobalt-60 calibration program has expanded markedly in the past

jars. During 1952, 300,000 millicuries were calibrated, and applica-

!; were received for calibrations of an additional 2,000,000 Mc that could

be accepted. A total of 1,221 radioactive standards were issued this year,

ijiding the I'^^ and P^-, Ra D + E, C^*, Co*^', radon, radium gamma-ray

|dards, rock samples, and alpha-ray standards. The Bureau measured

I certified 1,808 radium, mesothorium, and cobalt preparations; tested

jores and sludges and 24 water samples for radium content; made 868

*n determinations of air samples, 28 miscellaneous gamma-ray determiDns, and 6 leakage tests. Neutron measurements were carried out for Naval Research Laboratory, the Atomic Energy Commission Instruts Branch, the Naval Radiological Defense Laboratory in San FranD, the Radium Chemical Company of New York City, and the Univerof California. Demands for calibrated sources of thermal radiation inued at previous levels with 29 such standards issued.

I|,hirty-three mercury-198 lamps (a new and atomic standard of lengthj

p distributed. Eight went to universities and government institutions in

:ign countries and 25 were sent to places in this country; 4 to Government

atutions, 14 to universities, and 7 to private industries. This is the first fiscal year this program has been in operation.

lalibrations and performance studies of more than 40 r-meters and other

p meters (including ionization chamber, G-M Counter, photographic,

) were carried out for Government agencies, medical institutions and the

jeral public. Numerous tests have been carried out for Veterans' Adminption and other Government agencies on protective materials and devices

jjuse in X-ray installations. Among the items tested were lead-impreg-

^sd building blocks used in protective barriers, lead glass for protective

tidows, leaded aprons and gloves, and similar accessories. ^smistry

?iamples received for acceptance and regulatory testing numbered approxjitely 2,600. They covered a wide range of materials : organic protective

1 73
coatings and their components; soaps, detergents, and waxes; type- nbbons and carbon papers; metals and alloys; and reagent chemical

service of highly accurate analysis for carbon, hydrogen, and oxy?

organic compounds was maintained and called upon from time to tii other Government agencies. The Bureau calibrated 585 Magne.

27 000 nT.'' r TT'" '1^' electroplated coatings ; 27,000 NBS standard samples of certified composition were issued. Mechanics

Physical testing of materials, structures, mechanical apparatus, an struments for various purposes and calibrations of instruments continu a high level. In connection with the preparation of specifications for ing books for the blind, 40 phonographs were tested. Various acoustic

terials were tested for manufacturers and Government agencies Ca tions of 388 elastic calibration devices (proving rings, Amsler boxes, ah weighing cells etc.) were completed. Tension, compression, bending,

sion, and hardness tests were made to determine mechanical perform and compliance with specifications on a variety of specimens which incl reinforcing steel, aluminum and copper conductors, wire and fiber rop, pansion joint filler, and hand tools. Tests for compliance with specifica on an investigative basis were made on 8 mechanical appliances 14 r

sondes, 4 groups of electrical hygrometers, and 4 groups of mechanical h' meters. Evaluation tests were made on electric razors and watches fo Federal Trade Commission, on a newly designed postage meter for the

Office Department, and on dewpoint indicators and electrical pressure , ups for the Bureau of Aeronautics, Department of the Navy.

Over 700 water-current meters of various types, several pitot tub. number of special watershed indicators, and a plankton sampler were r- One hundred sixty master beer meters, used as primary standards by Bureau of Internal Revenue to check meters used in breweries to deten

revenue taxes, were calibrated. Thirty-eight wind speed-measuring in. ments were tested. Special purpose tests on instruments to be used as ondary standards were made on 574 instruments, including 474 timep^ and a number of mercury barometers used as working standards by the force and the Atomic Energy Commission.

The Bureau calibrated 8,540 weights for several State governments J

laboratories, various other Federal agencies, and for the general pu^ Volumetric calibrations were completed on 25,000 pipettes, more than 2' Casks, 2,500 hydrometers, 132 capacity standards, and 50 fluid me

Sixty-five density determinations were made. Nonroutine testing and , bration of gas-temperature-sensing instruments applicable in jet engines v conducted for the Air Force on the following types: bare, shielded,

total-temperature thermocouples; sonic-flow pyrometers; and an infr^ monochromatic radiation pyrometer.

74
, ranic and Fibrous Materials

irhe methods of test for automobile and truck tires developed during the

it two years in the NBS tire testing program have been incorporated m

'erim Federal Specification ZZ-T-381f, Tires, Pneumatic, Vehicle and

btable Equipment. Alginate impression materials, denture base resms,

Jergents for wax elimination, dentrifices, sterilizer oils, vibrators, mechami amalgamators, sterilizers, and vacuum investors were tested for the

intal Corps of the Air Force, Army, Navy, and the Veterans' Admmistrain Dental Service. Three hundred samples of light-sensitive blue paper

Lufactured in the NBS paper mill, along with standard faded strips, were

'iLlied to textile laboratories for calibrating fading lamps. The demand

standard samples of rubber compounding ingredients has continued to large A total of 6 of the original 7 has been exhausted and replacements obtained. A ninth, an oil furnace black, has been estabUshed. In

Operation with the American Society for Testing Materials, steps have

'5ien taken toward setting up a "standard" natural rubber. This standard

*:bber with properties determined by the National Bureau of Standards will

'j issued to rubber laboratories desiring to check their apparatus or

focedures.

Jietallurgy

'i^ Seventy items were examined for quality of material and compliance with

;^ecifications, for various Government agencies; 92 fusible boiler pugs

iere tested for the U. S. Coast Guard. About 750 castings of various alloys

i nd cast iron and special compositions were prepared in the experimental

bundry and 628 items were heat treated at the request of other Government

,4.encies' Miscellaneous services included rolling, forging, swaging, and

Iflre drawing of metals, determination of gases in metals, and metallographic

,End X-ray diffraction examinations.

'"^lineral Products

' The construction programs of the Federal agencies required an increas- U volume of tests on pordand cement and related concreting materials,

during the past year approximately 15.8 million barrels of cement repre- inted by 26,000 samples were tested as compared to 10 million m the pre-

' ious year. In addition to cement testing, 435 tests were made for Federal

Kencies on building stones and associated mortars and compounds, lest- L work on safety glass for compliance with the American Standards AsfLciation Code for Glazing in Motor Vehicles was continued for the various

TStates A wide variety of acceptance tests was conducted on refractory

' Tiaterials such as fire-clay brick, air-setting mortars, insulating refractory

i'pricks, flake graphite, and mullite brick. Six hundred standard sainples

iWere prepared and furnished to other laboratories for use m testmg calking

-Imaterials. The demand for the Cement Standard Fineness Sample has

been increasing steadily. ^ 75
Building Technology

St.-uctural tests were made on 71 samples of brick and concrete, \ masonry units, 87 units of pipe, and 10 prefabricated concrete slabs. V

tailed evaluation tests were made for the Department of the Army on lo . transfer devices for concrete runways, tent frames, and prefabricated m\

panels. Flamespread tests were made on 25 fabric samples, seven samp

;

of acoustical tile, and eight samples of fire-retardent paint. Exhaust t tests were carried out for the Coast Guard on 17 fire extinguishers; n. cellaneous fire-resistance tests were made on insecticides, waxes, deckin ; matches and match cartons, paint cans, roofing, and insulation. Therm

conductivity tests on the hot-plate apparatus were carried out on 53 sampl s 20 efficiency deteraiinations were made on air cleaners, and ten gasoL

lanterns were evaluated. Refrigeration equipment tested included elect

;

drinking water coolers, refrigerated warehouses, refrigerating units, a conditioning units, defrosting mechanisms, and a refrigeration compress

A total of 104 bituminous roofing and waterproofing materials were test for various Federal agencies; bituminous road materials tested for t i District of Columbia totaled 1,846 items. i Radio Propagation

There was a marked increase in the number of attenuators calibrated the X-band region, with most of the measurements made around 9300 !M The large increase was due both directly and indirectly to requests f^ calibration by defense agencies. For the first time a complete system

set up for calibrating attenuators in the 1 x 2-inch waveguide size (3951

5850 Mc). Forty-six VHF and microwave frequency meters covering

range from 300 to 26,000 Mc were calibrated. Forty-two waveguide ar' coaxial-type attenuators were calibrated. A number of power meters we

calibrated, including several in the UHF region. Calibrations and tes were made on 97 types of high-frequency radio equipment for the Goven

ment and the public. Standard frequency and time signals were broadca

continuously from WWV (Beltsville, Md.) and WWVH (Maui, T. H.), fc use in the calibration and test of frequency and time standards by the arme

services, research laboratories, and various industries. Weights and Measures ^ The Bureau tested and calibrated master railway track scales, railway te:, cars, commercially operated railway track scales, and other large capaciti

scales. Special tests were concluded on cordage-measuring devices, smak

capacity scales, and ice-cream measure-containers. Definite methods of tej were devised and refined. Calibration of large standards of mass was con

tinned. These calibrations included 50-pound weights of cast iron and al' weights over 50 pounds that were submitted to the Bureau by Governmen

agencies and industry. ^ 76
18. Cooperative and Advisory Activities

--•^Idvisory services are provided on many topics and problems for agencies

nLe Federal Government and State and municipal governments. Such

^lo;ctices were rendered to the Army, Navy, Air Force, State Department,

^v|tual Security Agency, Department of Agriculture, Department of In-

'^ior, Department of the Treasury, Post Office Department, Atomic Energy

•J5t} emission. Federal Communications Commission, Civil Aeronautics Ad-

^iiriistration, Federal Trade Commission, Naval Observatory, Veterans^ Ad-

:^ciistration, Civil Defense Administration, Defense Minerals AdministraJcii, Weather Bureau, National Research Council, Central Intelligence

-pfency. Armed Forces Security Agency, Coast and Geodetic Survey, Na-

*al Advisory Committee for Aeronautics, District of Columbia, Housing

?cti)H Home Finance Agency, Maritime Commission, Office of Rubber Re-

:a6|ve, Panama Canal, General Services Administration, Public Health

esfjjfvice, etc.

:est )jcontinuous and more extensive work is undertaken through various scit/tific and technical committees. The Bureau is represented on numerous

Immittees, panels, and commissions of other Government agencies. These

':lude the Interdepartmental Committee on Scientific Research andDevelJment, the Research and Development Board of the Department of Derd Cfise, the Federal Fire Council, the Interdepartmental Radio Advisory ComMh'ittee, the National Advisoiy Committee for Aeronautics, the Interdepart1 {dental Screw Thread Committee, the Building Research Advisory Board,

w; id a number of similar groups.

^ i'fcderal Specifications

2 An important phase of the Bureau's work consists m cooperation with the

jjleneral Services Administration and standardizing agencies in the developtes]j.ent and improvement of specifications. The GSA compiles and adopts

gjkcifications for the purchase of supplies by the Federal Government.

Jhtse specifications result in purchase economies by establishing criteria

J- .jhich .guarantee quahty and provide an opportunity for all business to com-

^'ete for Federal trade through the bid system. These functions are dis-

"^'biarged through 70 technical committees. A total of 120 positions on these

lommittees, including 25 chairmanships, are filled by specialists of the Buj^au's staff. Considerable experimental investigation is carried on at the

'jiureau in the development of test methods, which are often indispensable

jefore a specification can be framed or applied. Other laboratory studies ^fccome necessary in connection with the continual revision of the specifica-

^ft.ons to keep them abreast of industrial practices and the changing needs of :4ae Government. More than 2,200 Federal specifications are now in effect. M

JjHechanical and Electrical Equipment

ai| The Bureau was consulted on a variety of technical problems related to

jbotor vehicles. The numerous problems handled were relative to Governli 228268—53 6

"^"^
ment purchases of temperature-measuring equipment^ automotive e;q ment^ fuels, and lubricants. A new specification for automotive antifre was prepared for the Post Office Department. Information was furnij in reply to inquiries about automobiles and their accessories, including h

lubricants, and engine coolants. Consultation with the branches of Army, Navy and Air Force and their contractors on design, testing,

maintenance of airborne electrical and pneumatic equipment ( switches,

cuit breakers, air compressors, solenoid-operated control valves, and o components of pneumatic and electrical systems) continued to be import

Specifications were drafted for the Navy Bureau of Aeronautics for stoi bottles, pressure reducers, check valves, and pressure relief valves. Expert advice was given the Bureau of Aeronautics on the acoustic tr ment of noisy jet-engine testing stands and on the preparation of specif tions for acoustical materials (to be used for the sound insulation of

craft) . Related consultative services included advice on the design of Audiology Test Clinic for the Veterans' Administration, on the design c room for research in hearing at the Walter Reed General Hospital, on the design of a room for sonar listening tests at the Naval Resea

Laboratory.

The Office of the Chief of Engineers, Department of the Army, consul the Bureau regarding the reliability of tests made on friction losses in flow of water through corrugated steel pipes, and the Bureau of Pul

Roads was given advice in connection with a culvert problem. Represen

tives of the David Taylor Model Basin conferred in regard to the des

of a wave tank at the Basin. Assistance was rendered to the Army Corp

Engineers in density current problems.

Rubber

In connection with the stock piling of rubber, the General Services ministration has frequently been given advice in regard to the purch

and storage of natual rubber. Samples of rubber and rubber latex are

to the National Bureau of Standards by the General Services Administrati

for analysis and evaluation. Tests and evaluations have been made on n( types of natural rubber which do not have a place in the present syste of classification of natural rubbers. The Department of Agriculture oft requests the National Bureau of Standards to test and evaluate wild rubbe

The results are used for ascertaining the quality of rubber obtained fro various species of rubber trees. Fungus Proofing of Leather

The Second World War emphasized the need for a dressing for shoes whi(

,

would maintain them in a serviceable condition and prevent their attac by mildew in the tropics. A satisfactory treatment was developed for tb Quartermaster General, which contained paranitrophenol as the activ fungicide. Experience has shown that at least 0.2 percent (more than 0

78
44rcent is toxic) of paranitrophenol must be added to the leather to preit mildew growth.

The quantity of paranitrophenol in leather is easily controlled but in order

enforce the requirements in specifications, a method for determining the

isact amount present is necessary. Difficulty was encountered in extracting

le paranitrophenol from chrome-tanned leather used for inner soles, and

he Quartermaster General requested the Bureau to cooperate with several ^boratories to develop a reliable procedure for extracting all of the fungi-

^JKde from the leather. It was apparent that the paranitrophenol was being

pield in some manner by the leather, and it was found that the addition of in amount of water equal in weight to the leather freed the paranitrophenol

to:lo that it could be completely extracted by chloroform.

1^ j»lineral Products

ofji The Bureau furnished a variety of consulting services to other agencies

ic):|:n connection with the technology of mineral products. Measurements

.;iWere made on volume changes in a concrete floor laid over a lightweight

;aJfponcrete fill which had given considerable trouble to the Veterans' Admin-

],istration in a Chicago hospital. Tests were conducted on a disintegrated ^ concrete submitted by the National Advisory Committee for Aeronautics at Cleveland. An investigation for the Department of Interior was made of

the suitability of scorias in the Pribiloff Islands for the fabrication of conBj£ Crete building blocks in areas where wood is not available. Further tests were made for the Navy Department on the suitability of certain Hawaiian

Jji aggregates from an alkali-aggregate reactivity standpoint. Tests of a similar

I, nature were made on samples of North Dakota sands. Advisory assistance "was given the Technical Committee on Abrasives and Polishing Materials

of the Federal Supply Service in the development of specifications for abrasive-coated paper and cloth. k Building Technology

f The Bureau assisted a variety of Government agencies during the year,

)'| including State, county, and municipal agencies, in the solution of technical

f problems relating to building construction and materials. The volume of

P correspondence from the public seeking advice and information on specific

problems was very high: about 9,000 letters of inquiry were received and

answered, some 5,000 of which were from the general public, including home

owners and builders, supply dealers, engineering firms, architects, and educational institutions. At the request of the General Services Administration,

a detailed analysis was made of the causes of cracking of masonry for a number of Government agencies. In the field of fire protection, advice was

supplied to the National Archives and the Public Buildings Service on the

protection of historic documents, to the Army Corps of Engineers on the fire resistance of building materials and constructions, and to the Architect of the White House on reconstruction problems and the insulation of air-con- ditioning ducts. Consultative services were provided to a number of Federal

79
agencies on various phases of heating, refrigeration and air conditioning ai on roofing, flooring and related problems ; technical advice was given to 1

1

Army and the Navy on contracts for the repair and replacement of roofii'i and floor coverings.

Mathematics

The principal part of the activity of the mathematical services of tl Bureau consists of services given to other Government laboratories and the

;

contractors. Increased use is made of the NBS Institute for Numeric;;

Analysis for such services. The Bureau has undertaken the solution of speci; I problems in mathematical statistics for the Biological and Radiologics

Laboratories of the Army Chemical Corps, National Advisory Committe!

for Aeronautics, Ship Steel Committee of the National Research Counci]

Navy Bureau of Ships, and the Naval Ordnance Test Station (Inyokeri

California)

.

Radio Propagation

The Bureau regularly furnished the Department of Defense with the basi information used in preparing, for internal service use, recommended radi(

frequencies for various communication purposes. A variety of specific cir\ cuit problems were studied, and advice was given to the Air Force, Nava

Research Laboratory, Armed Forces Security Agency, and Department o: Interior. Assistance was given to the Air Force on calculations of a long-^

distance point-to-point communication system in the frequency range o1, 50 to 200 kc, and on problems related to radio navigational systems. Sug-i

gestions were given to a member of the Missouri State Geological Survey,

regarding techniques of radio geological sounding. Miscellaneous services were given to the Defense Minerals Administration on classification of micai

and to the Signal Corps Laboratory (Fort Monmouth, N. J.) on noise meter;

standards and calibration and on adjusting crystal-controlled oscillators. Advice was given to the Navy Bureau of Ships on rf noise measurements and

time measurements, the Coast and Geodetic Survey on reception of standard

frequencies and time signals in Liberia, Federal Communications Commis-,

sion and Bureau of Prisons on diathermy equipment, Naval Observatory on

:

quartz-crystal clocks. Naval Research Laboratory on impedance measurements, and Engineering Research and Development Laboratory (Fort Belvoir, Va.) on magnetic design.

National Cooperation

The National Bureau of Standards cooperates extensively with technical and trade groups, on a national basis, where the interests of the Government

are involved. Such cooperation is not only of value to the Government

but provides a means of disseminating the results of the Bureau's work to industry.

80
i's^j'eights and Measures

\s custodian of the national standards of measurements the Bureau pro-

|des calibration services to the Federal Government^ state and municipal

I l)vernments, universities^ industry, and private laboratories. The transtion of the basic standards of length and mass, and of the derived

. landards of capacity, to the channels of industry and trade is a matter of Teat economic importance to the producing, manufacturing, processing,

. ^pd distributing agencies in this country and to all purchasers of com-

"^^'jiodities. To aid in this work, the Bureau has an Office of Weights and

'^ ''Measures which assists in improving the standards of efficiency and cover- and increasing the degree of uniformity of State weights and measures

"^supervision throughout the United States. A program of assistance to

^^[tate and local departments of weights and measures as well as to business ^^nd industry has been pursued.

A large part of the activity consists in consultative services rendered

ibrough correspondence, consultations by representatives of Federal

|.gencies, business and manufacturing concerns, and w^eights and measures

>--''»fficials, and through field activities. The range of inquiries is broad,

-iimbracing the drafting of new legislation, interpretation of laws, specificairjijionSj tolerances and regulations, design of testing equipment, methods of

-f est of commercial equipment, and problems of weights and measures

C-kdministration.

'jl A major medium of cooperation with weights and measures officials, '•Equipment manufacturers, and associated interests is the National Con-

[•perence on Weights and Measures. The 37th meeting of this organization

[[(|A^as held in Washington in May 1952, with an official registration of 408,

!^.ncluding 179 weights and measures officials from 35 states and the District fpi Columbia, 121 representatives of manufacturers of weighing and measurping devices, 66 representatives of associations, business, industry, and rail-

.'•Itoads, and 33 representatives from Federal agencies. It is the responsibility the Office of Weights and Measures to plan and conduct the sessions of

I'tthe National Conference on Weights and Measures. The Chief of the

I'Office is the Secretary' of the Conference and the Director of the Bureau is its president. The most important standing committee of the Conference is 'the Committee on Specifications and Tolerances. This Committee is Jcharged with the responsibility of developing the technical requirements for

! commercial weighing and measuring devices w^hich are presented to the

' Conference for adoption, thence to the several States for promulgation.

Actions of the 37th National Conference included the adoption of further

specifications and tolerances for commercial weighing and measuring devices. Recommendations were made on soap bars and cakes; ice cream

and ices on sticks ; peat moss in package form ; Permalite, or any material

or substance of the nature or character thereof ; tomatoes in package form

prepackaged meats at retail; fractional terms of ounces: quantity declara81
Location of transmitter and receiver sites used in radio propagation studi

(p. 62). Two transmitters are on Cheyenne Mountain, Colorado, at elevatioi of 9,000 and 7,000 feet. Permanent receiver installations are located near Ke

drick, Karval, and Haswell in Colorado, and Garden City and Medicine Lodge

Kansas. Mobile units operate near Anthony, Kansas, and Fayetteville, Arkansa

tions on commodities in package form; and meats, fish, cheese, and pouhr

in plastic wrappings and casings. Scientific and Technical Groups

By actively participating in the projects of professional societies and stand,

ardizing bodies, the Bureau plays an important part in the development c

test methods and criteria, in the application of scientific discoveries, and i: fundamental research programs of a national nature. In this way the Bu , reau assists in developing and improving engineering standards, purchas e specifications, and building and safety codes. NBS staff members participate in over 100 national groups such as the Acoustical Society of America

American Society for Testing Materials, American Standards Association

American Society of Textile Chemists and Colorists, American Concret(

Institute, American Geophysical Union, American Institute of Electrica Engineers, American Society of Heating and Ventilating Engineers, Amer

ican Society of Mechanical Engineers, Institute of Radio Engineers, Instru' ment Society of America, National Fire Protection Association, Optica

Society of America, Society of Automotive Engineers, Society of Plastic In- dustry, American Petroleum Institute, American Ordnance Association

American Chemical Society, and National Association of Corrosion

Engineers.

The Bureau's participation in the work of these and related organizations

is largely through the activities of technical committees. Sixty members of the staff maintain personal membership in the American Society for Testing

Materials. Thirteen of these hold the chairmanships of main committees

dealing with such diverse subjects as magnetic properties, magnesium oxy

chloride cements, gypsum, asbestos products, porcelain enamel, electrical insulation, emission and absorption spectroscopy, textiles, w^ax polishes, plas

82
adhesives, and analysis of metals. Forty-three other staff members are imen of working committees while a still larger number lend assistance librving on technical committees and task groups so that in all about 425

Ijlinitteeships are held by Bureau personnel.

Participation in the activities of the American Standards Association is

^ ise through the work of technical committees. Bureau staff members

chairmen of ten main committees dealing with such subjects as the Naal Electrical Safety Code, Safety Codes for X-rays, Building Codes for

sonry, and standardization in the fields of Textiles and Photography. In

ition, Bureau personnel are chairmen of twenty-three working commitand occupy 220 other committeeships. ureau publications and technical reports are drawn upon extensively in

i| preparation of many standards such as the ASTM Method of CompresTesting of Metallic Materials in Sheet Form or the Specification for

ioini^l Bars for Concrete Reinforcement. Also, various items of equipment

^^^I'leloped at the Bureau form the basis of test methods, as for example, the

isaj^Liefer Abrasion Tester in specifications for textiles. The continuing proi ims of the Bureau in fire protection, building technology, electrical measments, and plumbing research are used as the basis for the periodic

fesion of American Standards and other codes in these respective fields.

tm]

or Science

TjThe basic facts of color vision have been discovered by researches in the

Tferse fields of physics, chemistry, physiology and psychology, but full utili- 'ion of these facts has been impeded because they have been scattered

^ oughout a very extensive literature and expressed in different terminol-

'[es. The Optical Society of America has provided a meeting place for

*ise diverse interests, and committees of this Society have been working

|iost continuously since 1919 to establish a unified consistent set of terms

tsing in the measurement of color and to collect and tabulate the quanti- Uve data. The basic ideas, terms, and data are completely presented for

e first time in a book. The Science of Color^ prepared by the Colorimetry

l)mmittee of the Optical Society of America (New York, Crowell, 1952)

a part of its cooperation with technical societies, the Bureau has contrib- ed importantly to this book. Much of the basic data wa.s developed in e laboratories of the Bureau; members of the staff have served on the

f*SA Colorimetry Committee throughout the years and have contributed to

[je writing and editing of The Science of Color. This book supplies the

jisic information required by America's technical experts to enable them to jake full and intelligent use of color standards in American industry.

research Associate Program

The research associate plan is an arrangement whereby technical, inastrial, and commercial organizations can support work at the Bureau on

Irojects which are of special interest to them, yet of sufficient general in- vest to justify use of Government facilities. Research associate projects

83
must not only be of value to all groups concerned in the particular field to the Federal Government, but must also be important from the standp

of the Nation's sum total of technologic knowledge. While the arranger

is preferably made \vith an association or group representing a major

of the industry concerned, projects may be undertaken in cooperation ^ single companies or individuals when the results may be expected to h

value to the general public. In any case, the results become a part of public domain and are published by the Bureau.

Since the research associate plan v/as estabHshed in 1920, more than'

organizations and individuals have supported cooperative research at Bureau. Many of the projects have been extremely specific and there

of relatively short duration. Others, such as that supported by the An: can Dental Association, have been directed toward fundamental rese^ in the field; this project has been active since 1930. Fourteen groups now supporting 35 research associates at NBS. Cooperative projects ' underway in pyrometry, soHd adsorbents, sugar refining, electrodeposit

plumbing systems, gas orifice meters, dental materials, cement test: crystallography, portland cement, porcelain enamel testing, asphalt n

ing products, and reinforced concrete. During the year fifteen papen

the various fields were published as a direct result of the research associf program work.

International Cooperation ' The National Bureau of Standards is active in such groups as the Inl national Union of Chemistry, International Telecommunications Uni

International Committee on Weights and Measures, International Scient

Radio Union, International Commission on Illumination, and Internatio: Commission for Uniform Methods of Sugar Analysis. These societies d

largely with the establishment and maintenance of international scient: standards and the establishment of values for scientific constants. Anotl

phase of international cooperation involves a program whereby scient: or diplomatic representatives from other countries are accepted at N

as guest workers or visitors. Both aspects, which are important to the Unit

States in terms of commerce and trade as well as the international polic cf the Government, are coordinated on the diplomatic level by the Sti Department.

International Intercomparison of Standards

The second international intercomparison of photometric standan

which has been in progress for the past several years, was complete

a final report was received from the International Bureau of Weights ai Measures (BIPM) in Paris. Adjustment of the units of the various cou

tries is not contemplated at this time. However, if adjusted on the basis the NBS values the maximum change in any U. S. value would be 0.3 pe

cent; other countries would have maximum adjustments ranging from 0. to 0.86 percent.

il

L

84
4 group of NBS saturated cadmium standard cells was taken to Paris

^ i comparison with those maintained at the International Bureau of 4ghts and Measures and those sent in by other national laboratories.^ A

^jiy of the results of the 1950 intercomparison showed that the electrical

Ijts of the various cooperating nations have been maintained satisfactorily fie the 1939 intercomparison. The study also showed that the change to

^'"f new absolute units as carried out in 1948 has been accomplished satistorily. ew Threads

urther progress toward common standards for screw threads for Canada,

United Kingdom, and the United States was made during the year by

^ efforts of the Interdepartmental Screw Thread Committee, A. S. A.

a^itional Committee Bl on the Standardization and Unification of Screw

[.reads, and the Bureau. A conference with Canadian and British dele-

||es was held in New York in June 1952. At this conference the British

t]jt:epted the American Standards for General Purpose Acme Threads and

:^eed to consider further the stub acme and the centralizing fit acme

^^reads. ^Vith regard to buttress threads, inasmuch as American indus-

^ij has not used buttress threads with a basic depth of thread as small as

•4 pitch (the depth used in Great Britain) , it was decided to add the British lindard as an appendix to the American standard; the British agreed to jtiprocate by including the American standard with 0.6 pitch thread depth

' the next printing of their standard. ternational Meetings

I The International Congress of Chemistry and the American Chemical

i'pciety held their 75th anniversary meeting in New York in September 1951.

jt^e Sixteenth Conference of the International Union of Pure and Applied

hemistry was held in New York and Washington during the same month,

f-'tany members of the staff of the NBS participated in the meetings. The

^aternational Union honored the Bureau by taking special notice of its 50th

i'lniversary, which occurred in 1951. Members of the NBS staff attended

I'lveral international conferences in the United States and in other countries,

fi official delegates of this countr\\

X^aternational Relations

i| Under authority of the Department of Commerce and several educational

Ikchange programs of the Department of State, such as the Mutual Secu-

|jty Act of 1951, Foreign Economic Assistance Act (Point IV), the United

Vtes International Educational Exchange Act (Smith-Mundt Act), the

'^ulbright Act, and others, the Bureau conducts visitor and trainee programs

T-hich permit foreign scientists and technicians to work, study, and visit at *ie Bureau. These activities not only strengthen the relations of this country

i./ith other nations, but also permit the National Bureau of Standards to keep

lore closely in touch with scientific developments in other countries and

i^enefit from them.

85
The Bureau also renders services to foreign countries in the form of te: calibrations, and exchange of standards, and also exchanges publications a world-wide basis. An example of an advisory service rendered to a forei country by the Bureau is shown by the service given to Costa Rica under t Point IV program. A staff member has been conducting a survey to det mine the "standards" requirements of Costa Rica and to make recommenc

tions for the establishment of a standards research agency. This service m \ be supplemented by a program for training personnel in the United Sta \ for work in such an institution. Plans are also being drawn for assistari to Brazil in establishing a modern paints, varnishes, and lacquers laboratoi

During the past year over 1,000 scientists and technicians, including ; special groups, visited the Bureau from abroad. They ranged from directc \ of research establishments similar to the National Bureau of Standards | postgraduate students. Twenty-seven guest workers spent 1 to 12 mont j at the Bureau observing or receiving training in a field of special interest j them. Countries represented included the Union of South Africa, Coloii

bia, Italy, Egypt, Pakistan, Spain, Uruguay, Formosa, Portugal and Ja\;

Some of the guest workers directly represented their governments wh j others represented private industry or institutions of learning.

Publications

The results of the Bureau's work are to a considerable extent presente" in the form of papers and reports. During the last year these totalc some 1,500, exclusive of those reports which have to do with calibratid

services and testing. Over 1,000 reports, classified and unclassified, we

prepared; most of these were issued to other Government agencies, pa, ticularly the Department of Defense, on projects supported by transferre funds. Approximately 500 papers and documents were issued for formal public;

tion. Of these, some 300 consisted of scientific and technical papers; 11 papers were published in the National Bureau of Standards Journal of R

search; the remainder were published in the familiar scientific and tecl nical journals of various professional, engineering, and trade organization In addition, 118 summary reports were published in the Bureau's Technic

News Bulletin. The third monthly periodical of the Bureau, Basic Radi

Propagation Predictions, presented each month, for a one-month perio three months in advance, radio-propagation data needed in determinin

the best frequencies to use in long-range radio communications.

Forty-three papers were published in the Bureau's nonperiodical serie of publications: 6 in the Applied Mathematics series, 5 in the Handbook

series, 16 in the Circular series, 6 in the Building Materials and Structure Reports series, and 5 in the Miscellaneous Publications series. A. V. ASTIN,

Director, National Bureau of Standards.

5

86
SCIENTIFIC AND TECHNICAL DIVISIONS AND

SECTIONS

^!

^1 ELECTRICITY

"^sistance Measurements. Inductance and Capacitance. Electrical Inj struments. Magnetic Measurements. Applied Electricity. Electro1 chemistry.

j OPTICS AND METROLOGY

!j 'ihotometry and Colorimetry. Optical Instruments. Photographic Technology. Length. Gage.

HEAT AND POWER

Temperature Measurements. Thermodynamics. Cryogenics. Engines

and Lubrication. Engine Fuels. Cryogenic Engineering.

ATOMIC AND RADIATION PHYSICS

^Spectroscopy. Radiometry. Mass Spectrometry. Solid State Physics.

Electron Physics. Atomic Physics. Neutron Measurements. Infrared

Spectroscopy. Nuclear Physics. Radioactivity. X-Rays. Betatron.

Nucleo.nic Instrumentation. Radiological Equipment. Atomic Energy

Commission Instruments Branch.

CHEMISTRY

rOrganic Coatings. Surface Chemistry. Organic Chemistry. Analytical

Chemistry. Inorganic Chemistry. Electrodeposition. Gas Chemistry.

Physical Chemistry. Thermochemistry. Spectrochemistry. Pure

Substances. MECHANICS

Sound. Mechanical Instruments. Aerodynamics. Engineering Mechanics.

Hydraulics. Mass. Capacity, Density, and Fluid Meters. ORGANIC AND FIBROUS MATERIALS

Rubber. Textiles. Paper. Leather. Testing and Specifications. Polymer

I Structure. Organic Plastics. Dental Research.

87
METALLURGY

Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallur.

Corrosion.

MINERAL PRODUCTS

Porcelain and Pottery. Glass. Refractories. Enameled Metals. Concre

mg Materials. Constitution and Microstructure. Chemistry , Mineral Products.

BUILDING TECHNOLOGY

Structural Engineering. Fire Protection. Heating and Air Conditioning

Floor, Roof, and Wall Coverings. Codes and Specifications.

APPLIED MATHEMATICS

Numerical Analysis. Computation. Statistical Engineering. Machin

Development.

ELECTRONICS

Engineering Electronics. Electron Tubes. Electronic Computers. Elec. tronic Instrumentation.

RADIO PROPAGATION

Upper Atmosphere Research. Ionospheric Research. Regular Propagation Services. Frequency Utilization Research. Tropospheric Propagation Research. High Frequency Standards. Microwave Standards.

ORDNANCE DEVELOPMENT

ELECTROMECHANICAL ORDNANCE

ORDNANCE ELECTRONICS

These three divisions are engaged in a broad program of research and devel- opment in advanced ordnance. Activities include basic and applied

research, engineering, pilot production, field testing, and evaluation of a wide variety of ordnance materiel. Special skills and facilities of other NBS divisions also contribute to this program. The activity is sponsored by the Department of Defense.

88
MISSILE DEVELOPMENT

^iissile research and development: engineering, dynamics, intelligence,

instrumentation, evaluation. Combustion in jet engines. These activities are sponsored by the Department of Defense.

OFFICE OF BASIC INSTRUMENTATION

OFFICE OF WEIGHTS AND MEASURES

o