A UNITED STATES DEPARTMENT OF COMMERCE

PUBLICATION mHoM Eureau of Standards

Library, E-01 Admin. Bldg.

9 1971

NBS SPECIAL PUBLICATION 325

U.S.

FPARTMENT

OF

100

TECHNICAL

HIGHLIGHTS

NATIONAL eUHHAU OF STANDA^k.

UNITED STATES DEPARTMENT OF COMMERCE

Maurice H. Stans, Secretary

Myron Tribus, Assistant Secretary for Science and Technology

i NATIONAL BUREAU OF STANDARDS

Lewis M. Branscomb, Director

1969

Technical Highlights

of the

National Bureau of Standards

Institute for Basic Standards Institute for Materials Research

Institute for Applied Technology Center for Radiation Research

Center for Computer Sciences and Technology

Annual Report, Fiscal Year 1969

Special Publication 325

Nat. Bur. Stand. (U.S.), Spec. Publ. 325, 243 pages (Mar. 1970)

CODEN: XNBSA

March 1970

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 (Order by SD Catalog No. G13/10:325) - Price $1.25
fWIONAL BUREAU OF STANDARD^

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FOREWORD

This report on technical highlights of the ^^ational Burean of

Standards is valedictory in nature. The report covers fiscal year 1969,

July 1, 1968 to June 30, 1969. Allen V. Astin, director of the Bureau

for 17 years, retired on August 29, 1969.

As Dr. Astin's successor, I am well aware that the progress evident

in this and in the preceding 16 annual volumes reflects the determining influence of a scientific administrator whose leadership strengthened U.S. science and technology in an era of tremendous change.

Building upon Dr. Astin's solid contribution, we hope in the years

ahead to draw inspiration from his work and to rise to future challenges in a similar spirit.

Lewis M. Branscomb, Dhector

Hi

CONTENTS

Page

FOREWORD iii INTRODUCTION 1 Staff and Organizational Changes 1 New Deputy Director Named. Office of the Associate

Director for Information Programs Established. Reorganization of the Center for Computer Sciences and

Technology. Advanced-Research Teamwork With Universities. Progress in Equal Employment Opportunities.

Transfer of NBS-GSA Test Development Division.

Programs Affecting National Policy and Consumer Problems 4

Metric System Study. Automotive Safety. Broader Protection from Flammable Fabrics.

CENTER FOR COMPUTER SCIENCES AND TECHNOLOGY 7 History of the Program 7 The NBS Computers. Research in Computer Components.

Computer Applications. Establishment of the Center. Recent Activity.

INSTITUTE FOR BASIC STANDARDS 21

Physical Quantities 21

International Base Units 21

Length. Time and Frequency. Temperature. Electric

Current. Fundamental Physical Constants.

Mechanical Quan tities 27

Electrical Quantities—D.C. and Low Frequency 31

Electrical Quantities—Radio Frequency 34

High-Frequency Region. Microwave Region.

Photometric and Radiometric Quantities 37

Physical Properties 39

Atomic and Molecular Properties 39

Solid State Properties 47

Thermodynamic and Transport Properties 49

Mechanical Properties 54

Applied Mathematics 55

Technical Assistance to Others 57

Advisory and Consulting Services 57

Conferences and Symposia 62

National Standard Reference Data System 64

Current Activities 66

Nuclear Data. Atomic and Molecular Data. Solid State

Data. Thermodynamics and Transport Properties. Colloid and Surface Properties. Chemical Kinetics. Data

Systems Design.

Information Services 71
Page

INSTITUTE FOR MATERIALS RESEARCH 73

Preparation and Characterization of Materials 73

Preparation 73

Synthesis.

Standard Reference Materials 95

Data on the Properties of Materials 109

Atomic and Molecular Data. Solid State Data. Thermodynamic and Transport Data. Chemical Kinetics. Surface

Data. Mechanical Properties. Optical, Electrical, and

Magnetic Properties. Reactivity and Corrosion. Engineering Materials.

Technical Assistance to Others 136

Advisory and Consulting Services. Conferences and

Symposia.

INSTITUTE FOR APPLIED TECHNOLOGY 141

Technological Measurements and Standards 141

Building Technology 143

Electronic Technology 150

Systems Analysis 154

Motor Vehicle Safety 156

Engineering Materials 158

Engineering Standards 160

Technical Support Activities 162

Technological Innovation and Diffusion 163

Invention and Innovation 163

CENTER FOR RADIATION RESEARCH 167

Radiation Measurement and Standards 167

Nuclear Physics Research 172

Radiation Theory 174

Structure oj Materials 175

Facilities Operations 176

Technical Assistance to Others 178

APPENDIXES 181

Organization of the National Bureau of Standards 181

Summary of NBS Staff as of June 30, 1969 188

Financial Data for Fiscal Year 1969 188

Research Associates and Guest Workers 188

Advisory Committees 190

Statutory Visiting Committee 190

Technical Advisory Panels 191

Awards and Honors 195

Education, Training, and University Liaison 198

Publications 200

Publications in the Bureau's Series 200

Publications in Outside Journals 210

Patents 240

vi
INTRODUCTION

Staff and Organizational Changes

The National Bureau of Standards has continuing responsibility

as the Nation's central measurement laboratory under terms of the

Organic Act which created it in 1901 and through subsequent amendments to the Act. In addition, as a result of changing technology and

through special legislative acts, new and expanding activities have

been undertaken over the years. Changes in Bureau programs and

activities have, not surprisingly, required redirection of administrative

and management emphasis.

Significant changes of the past fiscal year are discussed belov/. In

each case, the change was designed to make the Bureau more responsive

to needs of the commercial, scientific, and industrial groups which it serves. New Deputy Director Named

Dr. Lawrence M. Kushner was named Deputy Director of NBS in

May, 1969. He was previously the Director of the NBS Institute for

Applied Technology.

Office of the Associate Director for Information

Programs EstabHshed

The major organizational units at NBS that gather, analyze, and

distribute technical information have been combined under an Associate Director for Information Programs. The new arrangement brings

together related information activities that were previously managed

independently. It permits improved coordination, common policy

interpretation, and centralized and coordinated program planning,

budgeting, and evaluation.

The organizational components included in the new office are tlie Office of Standard Reference Data, tlie Clearingliouse for Federal

Scientific and Technical Information, the Office of Technical Infon nation and Publications, the Library Division, the Office of Public In- formation and the Office of International Ivelations. 1
The information activities of the new office range from those of the

Bureau's library, which primarily serves Bureau employees, to those

of the Clearinghouse for Federal Scientific and Technical Information, which is responsible for disseminating technical information

generated throughout the Federal Government.

Dr. Edward L. Brady, formerly Chief of the Office of Standard

Reference Data, has been appointed Associate Director for Information Programs.

Dr. Brady came to NBS in 1963 to serve as Chief of the Office of

Standard Reference Data.

Reorganization of the Center for Computer

Sciences and Technology

The Center for Computer Sciences and Technology, established

in 1966 in response to the Brooks Bill, has been made a separate organizational entity reporting to the Director of the Bureau. The purpose

of the Center is to develop standards and conduct research in the field of automatic data processing and to provide technical services to other

agencies for improving the cost-effectiveness of Federal programs in

the selection, acquisition, and use of automatic data-processing

equipment.

The Director of the Center, Dr. H. R. J. Grosch, received his B.S.

and Ph.D. degrees from the University of Michigan. In 1945 he

began his career in the data processing field with International Business Machines Corporation. In 1951 and 1952 he did logical design

research at M.I.T. and later went on to manage project DEACON at General Electric's Center for Advanced Studies at Santa Barbara.

From 1959 through 1965 he served as a consultant to major computer

and information handling business concerns in the United States and

Europe. Dr. Grosch has written articles on such diverse topics as celestial mechanics, lens design, numerical analysis, and the installation

of computer operations. For four years he was a contributing editor

of the journal, Datamation.

Advanced-Research Teamwork With Universities

Major moves toward increased cooperation with the Washington

area's institutions of higher learning were made when the National

Bureau of Standards entered into agreements with the University of

Maryland and George Washington University to facilitate joint efforts in advanced scientific research. The agreements are a continuation of

NBS efforts in the field of University-Government cooperation consistent with a White House memorandum in 1965 which encouraged

sharing of laboratory facilities. In particular, these agreements are 2
designed to encourage contributions to the Nation's research and

development from young scientists early in their careers. The participating universities and NBS are providing for greater use of the Bureau's personnel and facilities in furthering graduate

training and research, focusing imiversity competency more strongly on work geared to national goals, and establishing machinery for

close collaboration between each university and NBS in selected joint

programs. Under the agreements, every effort is being made to attract distinguished scientists to limited-term appointments furthering the

going projects, either at the Bureau or at the universities. Universityrelated activities engaged in by NBS staff are considered part of the

Bureau's normal activities, and activities of university staff and

students on joint projects at NBS are regarded as part of normal

university responsibilities. Supplementing the general agreement between the University of Maryland and NBS, a specific memorandum

of understanding has been adopted, providing for a Cooperative Program for Advanced Materials Research, teaming the Bureau's Insti- tute for Materials Research with the University of Maryland's Center

of Materials Research.

Progress in Equal Employment Opportunities

During fiscal year 1969 several steps were taken to improve the

NBS Equal Employment Opportunity Program. Among the steps were the strengthening of the EEO Conunittee, the establisliment of an Affirmative Action Plan for promoting equal employment opportunity, and a vigorous information program, highlighted by meetings

of the Director with the entire NBS staff explaining the Bureau's EEO

program and enforcement procedures for non-discrimination rules. The Affirmative Action Plan defined short-term and long-term objectives for the program, pinpointed responsibility for the achievement

of the objectives, and set target dates for their achievement. Objectives

include improved training and job enrichment for minority employees,

and monitoring efforts to assure adequate representation of qualified

minority employees on promotion certificates and training class rolls. The Education Committee established a subcommittee to improve

training opportunities for disadvantaged employees. Following the

subcommittee's report, an adult basic education program has been

planned to start in September, 1970, to prepare employees for technician courses. A new position is planned for a full-time counselor on

career development.

Transfer of NBS—CSA Test Development Division

For several years NBS has operated a testing laboratory for the

General Services Administration to develop new test methods and

3
run tests on specific commodities purchased by the Federal Supply

Service. In keeping with the general NBS policy of developing and

disseminating measurement expertise as widely as possible througliout

other govermnent agencies and private enterprise, the laboratory has

been strengthened and transferred to the General Services Administration. The transfer of the laboratory is appropriate, since GSA has

responsibility for qualified product lists and has the legislative authority to run a laboratory for testing products against standards.

Programs Affecting National Policy and Consumer Problems

Metric System Study

Since the August 9, 1968 enactment of Public Law 90-472 authorizing a Department of Commerce appraisal of "the advantages and dis- advantages of increased use of the metric system in the United States,"

the Bureau's exploration of the question in cooperation with other

groups has indicated that the study will be concluded on time and that

it will be possible to provide reasonable estimates for some of the

costs of any major U.S. changeover to the metric system.

The basis for estimated costs to firms has been laid by looking

at potential costs as they would accrue if metric measurements were

to be applied to new or redesigned products, stressing the concept of

planning a transition—if there is to be a transition—at an optimal

rate, without going back and changing all the drawings that are in

the files. This method, it is felt, avoids the exaggerations and "astro- nomical" figures which would result from a doctrinaire approach

based on an all-or-nothing plunge into metric measures throughout

U.S. science and technology.

Specialists conducting the NBS study have relied on the invaluable

orientation guide devised by the American National Standards Insti- tute for companies making metric studies. In this approach costs are being estimated on the assumption that metric specifications will be

used only for new, uniquely designed major components or end products requiring new special tooling—only after new metric standard

parts and materials are readily available at reasonable cost. This can

be accomplished on an optimum schedule as present product designs

become obsolete, on a timetable compatible with marketplace requirements and normal tool obsolescence. In some areas—for example, the

railroad and oilfield industries—changes in existing equipment do not

appear to be warranted.

Several questionnaires are being developed by NBS to aid in the

study. Companies which have already looked closely into the advantages and disadvantages of increased metric use are being queried, as are other companies which have not attacked the problem in detail. A

general questionnaire will be sent to both groups and their answers will

4-
be compared. Large Federal agencies Avill be asked by the Bureau to gage the probable effects that "going metric" would have on their areas of responsibility. The Department of Defense, in particular, has a study team working intensively on the question of what the impact

would be in the area of national security.

A series of NBS conferences is being planned to gather further data

and to provide an opportunity for representatives from the various

sectors of the economy to present their points of view.

An advisory panel has been organized to provide constructive assist- ance to the NBS Study Group. Members of the panel, which numbers

almost 50, were selected from a broad cross-section of the economy.

Great Britain's experience, and that of other nonmetric countries

undertaking a changeover, is being analyzed in the NBS study to see what the United States can learn from their accomplishments and

mistakes.

The Bureau expects to present to the Secretary of Commerce a detailed report on both domestic and international implications of

this issue—whether positive or negative—in order that the Secretary

may recommend a course of action to the Congress.

Automotive Safety

An agreement between the Department of Commerce and the Department of Transportation was extended to continue the ISTational Bureau

of Standards Office of Vehicle Systems Kesearch as an objective thirdparty resource to the National Highway Safety Bureau.

One of OVSR's major activities during the year was working on a uniform quality-grading system for tires to allow for an informed

choice by consumers. Objectives are to establish standard test methods

for several important tire properties, define quality levels for each

property, and develop a means of conveying the information to the consumer. Broader Protection from Flammable Fabrics

Procedures for carrying out the Secretary's responsibilities under new and amended sections of the Flammable Fabrics Act were published in the Federal Register of October 1, 1968. They included rules

for developing flammability standards by a four-step process. The NBS Fabric Flammability Section initiated research on the

transfer of heat from burning fabrics and related materials, of hazards

resulting from ignition of interior furnishings (beds and upholstered

chairs), and development of a statistical sampling technique for

investigation of deaths, injuries, and economic losses. After analyzing data from Consumers Union, the Department of

Health, Education and Welfare, and other sources, NBS recommended

to the Assistant Secretary of Commerce for Science and Technology

5
that he issue findings that there may be need for new or amended

standards for both clothing and carpets and rugs. Accordingly, on

October 23, 1968, notices were published in the Federal Register that new or amended flammability standards or other regulations, including

labeling, may be needed for wearing apparel. On December 3, 1968, a

similar notice was published, applying to carpets and rugs. The National Advisory Committee for the Flammable Fabrics Act

was appointed, effective January 1, 1969. The committee's 17 members—representing manufacturers, distributors, and the consuming

public—were selected by the Secretary of Commerce from among

more than 50 nominations. The committee is expected to be particularly helpful in giving guidance on priorities for efforts both in test- method development and in research.

The National Bureau of Standards organized a Symposium on the

Measurement of Flammability. Several hundred attendees heard representatives of industry, government, universities, and the medical

professions speak on the importance of heat, flame spread, toxic products, and ignition characteristics of wearing apparel, mattresses,

drapes, blankets, linens, furniture, and other items.

6
CENTER FOR COMPUTER SCIENCES AND

TECHNOLOGY

In the quarter-century since the electronic computer made its debut

in America, the National Bureau of Standards has been a leader in

the development of what is now the fastest growing technology in

the world. Greatly expanded since the forties, when early NBS re- search on computers was a partial function of the Ordnance Development Division and the National Applied Mathematics Laboratories,

the Bureau's program in this field today is carried on by the Center

for Computer Sciences and Technology under a Congressional mandate embodied in the 1965 Brooks Bill (Public Law 89-306).

This law and supporting policy guidance from the Bureau of the

Budget assigns to NBS the responsibility for: • providing guidance in the promulgation of hardware and software standards, both for industry-wide voluntary standards and Federal standards • providing other Government agencies technical assistance and consultation in both hardware and software areas in the eflacient use of computers • promoting training in the various areas of computer applications • providing information services related to computer technology • providing computer services—both use of equipment and programming

to other Government agencies

and • engaging in exploratory research. History of the Program

NBS involvement in electronic computing machines began as a part

of the Bureau's program of technical assistance to other agencies. In

1946, two of them asked NBS to provide specifications and deal with

manufacturers in the procurement of electronic computing machines.

For the Bureau of the Census, NBS contracted with Eckert and

Mauchley's Electronic Control Company for a UNIVAC; for the

Office of Naval Research, the Bureau contracted with the Raytheon

Corporation for a RAYDAC. Then the Bureau's own laboratories

became fully occupied with a two-year program for the development

of improved components for digital computers, carried out under

sponsorship of the Office of the Chief of Ordnance, Department of

the Army.

7
The NBS Computers

Work on the first UNIVAC followed an uncertain timetable be- cause of unforeseen technological and contractual difficulties ; delivery was made to the Census Bureau in 1951 after completion of extensive

acceptance tests designed by Dr. Edward Cannon and Mrs. Ida

Khodes of the NBS Applied Mathematics Division.

These were also the years of Project SCOOP (Scientific Computation of Optimum Programs), a pioneering effort to apply scientific principles to large-scale problems of military management and administration. The Air Force's Office of Air Comptroller had requested

that an NBS contract be amended to include a UNIVAC for Air

Force program planning applications under the project, but delays

in completion of both university and conmiercial machines led to a

request for a "stopgap" installation. The Air Force asked the Bureau

to launch a crash development program for a modest system designated as the NBS Interim Computer, renamed SEAC (Standards

Eastern Automatic Computer). In the summer of 1948, NBS explored

possibilities of designing and constructing a machine with sufficient power for general use and yet simple enough to be constructed

quickly. To supervise SEAC's construction, Samuel N. Alexander,

then chief of the Electronics Division's electronic computer section,

recruited from among von Neuman's group at Princeton a young

engineer and inventor named Ralph J. Slutz. Working with some 30

engineers and technicians, Slutz implemented the logical design of

Dr. Samuel Lubkin, formerly of the University of Pennsylvania's

Moore School of Electrical Engineering. When it became evident that

the proposed SEAC computer would be the only equipment available to NBS and collaborating Government agencies for at least two

years, the modest "interim" objectives were reconsidered. Dr. Slutz

and his team made improvements and additions to Dr. Lubkin's

original design and SEAC went into production in May 1950, just

20 months after its inception. It was the first general-purpose, internally sequenced electronic computer in operation in the United States,

and provided the initial high-speed computing support to Project

SCOOP until its UNIVAC was delivered in 1952. In additon to the UNIVAC's for Project SCOOP and the Census

Bureau, a third UNIVAC for the Army Map Service was contracted

for by the Bureau. Another computer, SWAC (Standards Western

Automatic Computer), was being built at the Institute for Numerical

Analysis, a section of the NBS Applied Mathematics Division, at Los Angeles. Operative early in 1952, SWAC differed from SEAC

in using a parallel mode of operation. Its primary memory was composed of Williams tube units, enabling all digits of a number to be

placed in memory or transferred simultaneously and arithmetic

operations to be performed in parallel. SWAC's development was 8
SEAC, NBS's first computer, was completed in 1950. For the fourteen years of its useful life, SEAC was used by dozens of other government agencies ; portions

of this computer are now preserved in the Smithsonian Institution.

The NBS liaS/UNIVAC facility also serves as a service center for government

and is available to all government agencies. Many users are served by computer

terminals, some as far away as 2,000 miles. This modern facility is able to deliver results more than 1,000 times as fast as the pioneer SEAC.

9
jointly sponsored by the Air Force's Office of Air Eesearch, from

interest in the performance of the machine itself, and the Office of

Naval Eesearch, from interest in programming and mathematical

research. SWAG was used in the solution of many aircraft problems

by several Federal agencies; it was ultimately turned over to the

University of California at Los Angeles, where it remained in use

for 15 years. While working on SEAC and investigating the possible creation of

other machines, Bureau specialists decided that SEAC's dynamic

circuitry could lend itself to considerable electronic standardization.

This is turn provided a basis for a repetitive physical configuration

and the assembly of high-level pulse circuitry.

The combined efforts of E. P. Witt and E. D. Elbourn produced a package design which, with some refinements, was used in two computing machines that were essentially modified copies of SEAC

FLAC at the Air Force Missile Test Center and MIDAC at the Willow

Eun Eesearch Center, University of Michigan.

NBS revised this package design to incorporate etched circuit

techniques. Such packages were used in constructing DYSEAC, designed by A. Leiner, W. Notz, L. Smith, and A. Weinberger and completed in 1954. This project was sponsored by the Eesearch and Development Board for the evaluation of various organization and

engineering innovations, among them the location of the equipment

in a trailer for purposes of mobility. DYSEAC was used by the Signal

Corps at White Sands, New Mexico.

Combining digital and analog techniques, the Bureau solved several

unique problems, such as the development (for the Weather Bureau

and the Atomic Energy Commission) of a special-purpose computer

for predicting the radioactive fallout pattern for a 250-mile radius

from the detonation point of a nuclear device.

Eecognition of the need for a multi-processor stimulated the design

of the Pilot Data Processor in the late fifties. Pilot combined a central processor, a satellite processor, and an input- output format controller. Used for experimental information processing in the early sixties, it was not considered feasible to move the one-of-a-kind vacuum-tube

machine with its limited software to the new ''jite when NBS shifted its headquarters from Washington to Gaithersburg, Maryland.

Typical of new NBS projects in computer development to assist other agencies were the AMOS IV (Automatic Meteorological Observation Station), designed to serve as the central element of an auto- matic system to process data for the Weather Bureau, and ACCESS

(Automatic Computer-Controlled Electronic Scanning System) for

handling information on the Nation's resources.

10
Research in Computer Components

Originally sponsored at NBS by the Chief of Ordnance, Department

of the Army, research on computer components gained impetus when

basic components of the first UNIVAC for the Census Bureau had to be evaluated for performance and reliability. As specifications were

being written for the UNIYAC, some research efforts were directed

to the mechanical aspects of components such as tape drives and

keyboards.

Jacob Rabinow was heavily involved in this work, and as his group

began to experiment with magnetic recorders using wire and tape, he

invented the magnetic particle clutch in 1947. At the request of Army

Ordnance, the Rabinow team initiated the design of a large-capacity

magnetic memory which resulted in the notched-disc file in the early

fifties. Efforts were concentrated on developing basic components, including

storage devices, input and output equipment, and associated specialized

electron tubes for such computing functions as gating, switching,

delaying signals, interval timing, and pulse shaping. Two prototype

high-speed memory units were developed, one using cathode ray tubes

and the other diodes and capacitors as the storage units.

One of the devices developed during this period was the magnetic

wire cartridge, a simple input-output device that recorded on and

read electrical pulses from magnetic wire. This was used in all of the

automatic electronic computing systems designed and developed by

NBS : SEAC, SWAC, DYSEAC, and the Pilot Data Processor, as well as in SEAC's two offspring, MIDAC at the University of Michigan and FLAC at the Air Force Missile Test Center. Analog-digital techniques were used also in the design and implementation by J. P. Nigro of NBS and his team of a man-machine

systems simulator for the Wright Air Development Center and the

Federal Aviation Agency. Resulting techniques were employed in the

early sixties for designing MAGIC I and MAGIC II, cathode-ray

display devices used with light pens as manipulative controls in con- junction with a computer in applications such as computer-aided

design, electronic circuit organization, file information retrieval, lin- guistics, and others requiring computer graphics in the handling of

two-dimensional information.

Electro-mechanical problems associated with the transport and

rapid start-stop features of the Rapid Selector engaged NBS attention

as a result of Dr. Vannevar Bush's interest in this microfilm machine,

which was able to search large amounts of data and retrieve particular

sections by means of codes recorded on the film. At the same time, the

Bureau continued research on the magnetic tape-handling device and

the high-speed card punch.

375-572—70 2 11
A corollary development was FOSDIC (Film Optical Scamiing

Device for Input to Computers) for the Census Bureau. FOSDIC,

using optical, mechanical, and electronic techniques, scanned microfilm

of hand-marked census forms and recorded the data on magnetic tape

for input to a computer. So useful was FOSDIC for scanning forms

and graphic material that advanced and more flexible versions were

later devised not only for the Census Bureau but also for the Weather

Bureau and the Office of Emergency Planning.

After FOSDIC the next step—accomplished through another of

Jacob Eabinow's inventions—was the development of OCR (Optical

Character Reading) facilities, and an experimental model of a Best- Match Reading Machine emerged in the early fifties. This machine,

demonstrated in 1954, is now on exhibition at the Smithsonian

Institution.

Computer Applications

Mathematicians in this country and abroad were attracted to the use of the powerful tools represented by SEAC and SWAC. A large group

of numerical analysis specialists was built up around each computer,

devoting their efforts primarily to the development of linear pro- gramming techniques and the restructuring of equations for greater

ease in handling by the machines.

SEAC's first solution to a real problem was marked by the May 9, 1950 successful run of the program for tracing skew rays through an

optical lens system. This was programmed by Ethel Marden of the

NBS Applied Mathematics Division. Mrs. Marden, with Otto Steiner

and Ira C. Diehm, represented the entire programming staff for SEAC

at that time, but additional personnel were recruited at a fairly rapid

pace from the Bureau's mathematics staff, and a series of training

courses in computer work was undertaken for NBS and other Government employees. Outside personnel—including employees of other

Government agencies, university staff members, and prominent foreign

mathematicians—were frequently detailed to the Bureau for training.

In addition to several optical problems, early applications were

concerned with heat flow, analysis of crystal structures, and simulations related to wind tunnel designs, airfoil characteristics under vari- ous conditions, smog-producing factors, and statistical analyses. There was no lack of mathematical and scientific problems, both from within

the Bureau and from other agencies, and they were of remarkable

variety.

Concentrated attention was given to two areas of mathematics

:

• Numerical analysis for investigation of series approximations and

other numerical approximation techniques tailored for computer handling of mathematics (some of this work helped to 12
provide a basis for revised mathematics curricula at all three

levels of the educational system)

.

• Algebra, matrix manipulation, and linear programing techniques

(with applications for purposes of aircraft deployment and

maintenance during the Korean war, in bid evaluation for the

Army Quartermaster Corps, and in other fields).

In the early fifties, after SEAC made the first contributions to H-bomb design calculations. Dr. Allen V. Astin, NBS director, re- ceived a letter of commendation from the Atomic Energy Commission.

Programing research and mathematical research for computers advanced together at NBS. The Computation Laboratory, under Dr.

Joseph Levin, developed a library of subroutines, including double

precision and floating-point operations, and some of the pioneeringsoftware such as "interpretive" programs. Joseph Wegstein devised a simple assembly language for SEAC in the early fifties. He chaired

the international committee that developed the i^LGOL language and

was the first chairman of the committee that later developed the

COBOL language.

Early work on management information systems included studies

for the Social Security Administration, the Treasury DejDartment's

savings bond division, and the Navy's Bureau of Supplies and Accounts. In the mid-fifties there were investigations of common process- ing problems such as sorting and file management. Ida Rhodes

developed a combined sorting and file-merging program using pushdown store techniques. For the Public Housing Administration a method of generating reports from raw data, based on automatic error- detection and logical-consistency checking techniques, was developed.

Work on pattern recognition, pictorial data processing, chemical

structure searching, and natural language processing also began in the

mid-fifties. It gained impetus when, upon recommendation of the Bush

Committee, a collaborative research program with the U.S. Patent

Office was established in November 1954. Element-by-element dhemical

structure search (Ray and Kirsch) and HAYSTAQ, a searching sys- tem capable of multiple tracings of variable constituents of nodes of

chemical structure representations (Marden), were demonstrated be- fore 1958. Interest in optical character recognition (OCR) began as an important possibility for computer input. NBS supported work on a demonstration model of an electronic version of Rabinow's Diamond

Ordnance Fuse Laboratory "First Reader" and surveyed OCR possibilities for the Social Security Administration, the Rome Air Development Center (RADC), and the Army Signal Corps, among

others. Participation in OCR standardization efforts of the United

States of America Standards Institute (then the American Standards

Association) also began in the formati\'e years of these efforts. 13
The R.ADC project involved general problems of pattern recognition for which a programmable scanner (Kirsch, Cahn, Ray, and

Urban, 1957) was developed. It was applied to studies of local operations on pictorial data (Thomas), to continuing analyses of biological

tissue data (Kirsch) and of micrographs of metallurgical sj^ecimens

(Moore).

Kirsch and Rankin in 1955 began taking a linguistic approach to pictorial data-processing, now continued by Rankin. The fifties were

also notable for work on analysis of electrocardiograms in cooperation

with the Veterans Administration (Marden) and traffic simulation

projects (Stark).

Among NBS contributions to natural language processing in con- nection with information selection, storage and retrieval systems were

the development of a small-scale question-answering or fact-retrieval

system (Stevens), the development of a KWIC-indexing system

(Stevens), and experiments in automatic classification or indexing

(Stevens and Urban)

.

DYSEAC, designed in 1951-54 by Leiner, Notz, Smith, and Weinberger, was interconnected to SEAC to bring about a time-sharing,

multiprogranmiing and multiprocessor capability. This mobile computer was used in conjunction with radar scanning and on-line display

equipment to demonstrate air traffic control applications, and the in- terconnection of SEAC and DYSEAC was made in April 1954 in order

to demonstrate multiprocessing.

Ever since 1950, when the Bureau first was asked to advise the Post

Office Department on automation, NBS has cooperated in the effort to provide increasingly sophisticated tools for carrying on this mammoth operation. The Bureau's advice and assistance has covered the

overall improvement of mail-handling, including mail-sorting codes

and the design and selection of equipment ranging from keyboards

and automatic mail sorters to automated post offices. After the Bureau acquired an IBM 704 in 1957, SEAC continued

to be used solely as a research facility for equipment and programs

until its retirement in April 1964. The 704, later followed by a 7090,

a 7094, and a UNIVAC 1108, served not only NBS needs but also those

of other agencies which either did not have computers or were not

fully equipped in this area. With the move toward larger and more complex equipment, NBS

computer work took new directions

:

• greater emphasis on sophisticated software essential to efficient functioning of larger computers • broader applications in data processing, complex file manipulation, pictorial data processing, library functions and document

handling, large operations research problems, and others

14
• development of language and other user aids to increase programmers' efficiency • standardization.
Establishment of the Center

In response to the new responsibilities given it under the Brooks

Bill, the National Bureau of Standards brought together several units

in 1966 to form the nucleus of a new organization called the Center for

Computer Sciences and Technology.

The structure of the CCST reflects the nature of the additional

responsibilities given to NBS and the broadened scope of its role in

connection with computer operations in government. The underlying

theme of that role calls for the CCST to improve the effectiveness

and efficiency of the Government's use of computers. To that end

emphasis has been focused primarily on standards and on providing

technical advice and assistance to other agencies through computer

systems design and development and through directed research in

critical areas. Other functions include the operation of a computer

service center for government and the provision of information on

activities and personnel in the computer technology.

The first director of the CCST was Mr. Norman J. Ream ; he was

followed by the present director, Dr. H. R. J. Grosch.

Recent Activity

During fiscal year 1969 the Center broadened its contributions to computer sciences and technology as employed both in the Federal

Government and in the private sector. Among steps taken were

:

• Establishment of an official publication medium, the Federal

Information Processing Standards Publications (FIPS PUB),

for information relating to standards adopted and promulgated

under the law. Nine FIPS PUBS were developed in fiscal 1969. • Implementation of the Federal Standard Code for Information

Interchange and related media standards, through detailed

instructions issued by Secretary of Commerce Maurice H.

Stans to heads of Federal departments and agencies. The Code

defines a set of 128 characters commonly used in information

processing and communications. Among other things, instructions are provided for new installations, replacements of computers, augmentation of existing configurations, interchange

situations, and ADP/telecommunication interfaces. • Development of a new unrecorded reference tape standard, in

cooperation with an NBS research associate sponsored by the

International Business Machines Corporation. This work on

amplitude reference magnetic computer tapes was undertaken

at the request of both national and international magnetic-tape

16
standards bodies. The General Services Administration will use the resulting secondary tape standards for calibration of qualification test equipment. • Launching of a program, in cooperation with the industry, to develop a standard unrecorded magnetic reference surface for

ready interchange of magnetic disc packs among equipments of

different makes and models. • Establishment of a new Federal Information Processing Standards Coordinating and Advisory Committee, with members

representing the Bureau of the Budget, General Services Administration, Department of Defense, Atomic Energy Commission, and National Aeronautics and Space Administration.

The new committee works through five inter-agency task groups on Transition to Federal ADP Standards. • Federal adoption of a voluntary commercial standard for the

COBOL programming language, approved and published

with the active participation of CCST staff—by the United

States of America Standards Institute (now American National Standards Institute). This will facilitate the interchange

of computer applications, programmed in COBOL, among

Federal agencies. Work is continuing on the development of

evaluation and validation routines, a necessary adjunct to Federal adoption of the commercial COBOL standard. • Intensification of measurements automation research and development, emphasizing functional modularity and flexibile storedprogram control—concepts which not only help to serve the

needs of the Bureau's own laboratories but also appear with

increasing frequency in commercially available instruments for

making physical and electrical measurements and collecting,

recording, and processing experimental data. • Technical assistance in cost-saving, efficiency-promoting operations such as the application of digital computers and ADP

technology to geophysical data-processing, fingerprint process- ing and identification systems, computer-controlled calibration

of jet-fuel engine pumps, and development of a general microscope input for a computer (used at the National Institutes of

Health). • Development of "anticipation techniques" and appraisal of fac- tors influencing optimum design of man-machine systems, as part of a point study in cooperation with the National Aeronautics and Space Administration's Electronic Research Center. The new techniques are being applied in continuing

experimental activity involving display and time-sharing

equipment in NBS laboratories.

17
Development and study of hardware and software techniques for

interconnecting various computer processors and peripheral

equipment. The NBS-designed-and-constructed MAGIC II

display terminal has been interfaced to the MOBIDIC B TimeShared Computer Kesearch Facility and several smaller devices

have been attached to MAGIC II and MOBIDIC.

Implementation of a general-purpose system for storing data and

programs on disc files within the NBS CORD Time-Sharing

System. The system employs novel techniques for improving

access to files stored on disc and for improving the reliability

of file storage.

Utilization of the NBS CORD Time-Sharing System and the new disc file storage mechanism to help implement an information storage and retrieval system for data describing a specialized collection of documents in the on-line systems and computer

display areas. Besides being a useful tool to support the re- search program, this retrieval system is being used to study

tradeoffs between manual and automatic search of a specialized

data base with respect to the efficient use of manpower and

equipment.

Implementation, within the NBS CORD Time-Sharing System,

of a conversational version of a language developed at Bell

Telephone Laboratories for efficient list-processing. This sys- tem, designated CL6, incorporates compilation, execution, and

debugging facilities in a flexible manner within a highly interactive supervisory system.

Development of a graphical assembler for generating display

processor code on the larger time-sharing system, and implementation of a graphical debugging system to mmimize the

time necessary for obtaining operational programs for display

applications, taking into account the advantages of using the

graphical display during the debugging process. Further development of a class of program generators that will

enable an instructor to produce a Computer Assisted Instruction (CAI) course as the result of an interactive process; and

continuation of studies on the generation of "generators" in

order to explore the possibility of using this approach to produce computer programs of all types.

Investigation of a programming language that (1) is a dialect

of a standard programming language, hence uses an existing

compiler; (2) permits content addressing, eliminating the need

of a user to be concerned with the mechanics of search or

indexing, and (3) permits dynamic creation of files for intermediate output or cross-reference indexes.
• Application of two-dimensional linguistic techniques—used

earlier by NBS for development of grammars from Chinese

ideograms—^to the analysis of other means of communication

such as chemical-structure diagrams. Sponsored by the National

Institutes of Health, the research is expected to extend the

linguistics discipline and provide easier means of interfacing

with a computer in the area of graphics. • Experimentation with an information retrieval system for

pharmacological data, designed for the National Institutes of

Health, with special consideration given to the construction

of numerous special-purpose files containing a variety of in- formation, including chemical structures. Such a system would

help scientists to draw significant correlations of data for determining the effects of chemical substances on the body. • Expanded design work for management and intelligence information systems applicable to tasks performed by the Agricultural Eesearch Service, the Public Health Service, and Jaw

enforcement agencies. • Increased use of digital computers for automating experimental

and research work in NBS materials and basic standards laboratories. Computer-controlled data acquisition and control of

experiments are now being widely applied to improve experimental accuracy and reproducibility, reduce errors and repetitive labor, more tightly control parameters, permit very high

data rates and very lengthy experiment time, and increase

experiment throughput. • Collaboration with technical societies and professional organizations to develop improved means for exchanging information recorded on magnetic tape, with emphasis on arrangements

for sharing the task of descriptive cataloging and recording

data elements in advance of the exchange of tapes. • Drafting of a proposed plan for preparing a roster of sources of computer programs and documentation, and publication of

a report embodying a "Recommendation for Formats for Computer Program Catalogs,'' based on an evaluation of existing

formats and the information that should be available about a program in order to decide on its applicability to the solution

of a specific problem. • Initiation of a research project for extending the classification

scheme for computer information. This is being carried on with

the advice and support of the American Patent Law Association's subcommittee on computer information classification, in

conjunction with the Association for Computing Machinery. • Testing and evaluation of a simplified single-fingerprint identification system designed to allow the computer code for a finger19
print to be easily written and sent to any central computer for a report on the probable identity of a suspect, amnesia victim, or corpse. • Experimentation under the C'CST's natural language processing

program for purposes of improving information selection, stor- age, and retrieval systems; developing and using automatic

classification and indexing techniques ; applying selective recall techniques to both associational files and natural language texts

;

and developing on-line search strategies for text processing. • Completion of selective literature reviews on Information Acquisition Sensing and Input, Information Processing Storage and

Output, Overall Systems Design Consideration, and Privacy,

Confidentiality and Security. • Provision of data-processing services during fiscal 1969 to 60

organizations including 10 executive departments, the Executive Office of the President, and 15 agencies of the Government,

the Congress, and State and local governments, quasi-government organizations, and universities. Assistance in evaluating

and selecting automatic data-processing resources was given

to the U.S. Civil Service Commission, U.S. Army TACFIRE

headquarters, Commerce Department officials concerned with

automated personnel systems, the Equal Employment Opportunity Commission, and the Harry Diamond Laboratories. • Development of operating software to handle remote access from

keyboard terminals, expected to permit remote job and data

entry from Model 33 or Model 35 Teletypes and to make possible

future support of such applications as text editing, remote file inquiry, and conversational compilers. • Installation of a "Graphical Display System" software package,

developed at the University of California, allowing the user

to generate a graphical display from his source program by

using a standard set of simple specifications. The display can

then be directed, by simple control card changes, to any of the

available display devices.

20
INSTITUTE FOR BASIC STANDARDS

The primary responsibility of the Institute for Basic Standards

(IBS) is to provide the central basis for a complete and consistent

national system of physical measurement, coordinating that system

with those of other nations, and furnishing the essential services

leading to accurate and uniform physical measurements throughout the

United States. The IBS staff of 900 includes 528 scientists and engineers, 200 at the Ph.D. level, in facilities at Gaitliersburg, Md., and

Boulder, Colo. In addition to these primary locations, specialized

activities are carried out at Fort Collins, Colorado ; Areata, California; Maui, Hawaii; and an abandoned gold mine in the Colorado

Kockies. The broad nature of the IBS responsibility requires work at many levels of teclinical sophistication ; however, the critical contributions in measurement generally lie at the frontiers of science and

engineering.

PHYSICAL QUANTITIES

The international system of measurement is based upon six quantities: mass, length, time, temperature, electric current, and luminous

intensity. All other physical quantities can be derived from these six. The United States and most of the other nations base their local systems upon these, but since it is impractical to make all measure- ments directly in terms of the base units, standards for the other

physical quantities have been developed which are consistent with

them.

In a high technology society, the needs for better standards and means of measurement—more precise, stable, and easily disseminated

increase continually. Some of the current research in this area is described below.

International Base Units

Length

Dynamic Distortion of Laser Rods Using Holography—Holographic interferometry methods, and high speed photography have

been combined to investigate the distortions of solid state laser rods

21
caused by optical pumping, lasing and subsequent cooling. In this

technique, the optical wavefront generated by passing continuous laser light through a passive rod is recorded in a hologram. If the wavefront then changes, interference fringes are produced by the hologram

which interferes the recorded wavefront with the new one. Distortions

of the active rod create rapidly moving fringes which are photographed using a high speed camera. The films thus obtained can be

evaluated at a much slower speed and analysis of the distortion is readily made. Ruby rods have been tested using this method and a convex distortion has been observed at several pumping levels. The

information obtained by this method will make possible the manufacture of laser rods which are optically flat in the active state. Measurement of the Internal Diameter of Small Holes—The development of a new system for measuring internal diameters of small bore

tubing utilizing capacitance techniques constitutes a significant

advance in metrology, as well as contributing directly to the accuracy

of the NBS gas thermometry program. The technique permits measure- ments at any position inside a tube up to 1 meter from its end, and can

be used for tubes having diameters as small as 0.5 mm to an accuracy

of approximately % /x in diameter. It has been used to measure the

"dead space" that is part of the gas thermometer volume.

Saturated Absorption hy Neon Inside a 6328 A Laser—The stability

and reproducibilty of a 6328 A He-Ne laser locked to the saturated

absorption peak of a pure neon discharge inside the cavity are being

studied. In the He-Ne : Ne system however the pressure induced shift in

the gain curve results in the situation where the absorption peak (due

to the low pressure cell) does not occur at the maximum of the tuning

curve. The frequency output of this laser is therefore expected to be

sensitive to excitation conditions. It has been found that by utilizing

the isotope Ne^^ in the absorption cell and a mixture of about 8 percent

Ne^o and 92 percent Ne^^ as the neon component of the gain cell the

maximum of the gain curve can be shifted to the same frequency as that of the absorption peak. This is expected to increase greatly its usefulness as a wave-length standard.

High-Accuracy Laser—Since the invention of lasers, it has been

assumed that they would eventually lead to an accurate standard of

length. This has now been accomplished by stabilizing a 3.39 fxm helium-neon laser to the center of a methane infrared transition. The

method used is known as "saturated absorption." The laser beam

passes through a cell containing methane vapor at low pressure, and

it partially saturates the methane transition so that the absorption

coefficient is reduced. If the laser beam is tuned even one part in a

billion away from the methane transition frequency, the saturation is substantially less and a greater amount of the laser light is absorbed.

The resulting narrow peak in the transmitted laser light is used to 22
automatically keep the laser adjusted to the proper frequency. The

shift with methane pressure has been shown to be very small. Two

independent devices have been built, and their frequencies agreed to one part in a hundred billion. Such highly stabilized lasers may be

used as the basis for a new definition of the meter which would be over 300 times more accurate than the present definition.

Time and Frequency

World-Wide Standard Frequency and Time Signal System—NBS

has traditionally provided strong support to the International Radio

Consultative Committee (CCIR). This organization's Study Group

YII (currently chaired by a senior NBS scientist) met in Boulder,

Colo., in July of 1968 to discuss standard frequency and time signals.

At the suggestion of the United States delegation, an intemutional

working party was set up to assure more active coordination on the

important question of improving the worldwide coordinate time sys- tem, UTC. Reports initiated chiefly by the United States delegation

led to international recognition of the conceptual distinction between

time interval measurement (metric time) and coordinate time sys- tems and intervals. There was also recognition of the challenge posed

by space and aircraft navigators who need a widespread synchornized

timing system of high precision.

Advances in Satellite Timing Techniques—New experimental statellite time dissemination experiments were conducted. The experiments

utilized a synchronous satellite, positioned over the Galapagos Islands,

designed to cover the Americas as well as some ocean regions. Primary

design considerations were economy, simplicity, and versatility. A

"listen only" technique was employed, eliminating the need for trans- mitting capabilities at user stations. In the first phase of the experiment, the basic timing format was tested; results indicate that the

user can easily obtain an accuracy of 100 microseconds and that with more care 10 microseconds may be obtained. Voice announcements

will be added at a later date. TY Time-Frequency Dissemination Studies—The use of television

to disseminate time and frequency has been investigated. An initial study made use of a local TY station to synchronize the NBS WWV

master clock at Fort Collins, Colo., with the NBS time scale maintained at Boulder, Colo. TV synchronization pulses were monitored

and the difference in their arrival time at the two locations was noted.

With this information and accurate knowledge of the difference in

propagation delay time between the two locations and the TV sta- tion, the time difference between the two clocks was obtained. Recent

work between Boulder and Cheyenne, Wyoming, indicates that this

method can be used to synchronize clocks to a few tenths of a microsecond. Besides its use in clock synchronization, television is a vahiable

23
source of frequency information. Measurements made at Boulder on

a 3.58 MHz color subcarrier originating in New York City have demonstrated that precision of a few parts in 10^^ may be obtained for

15-minute averaging times. Since the major networks use rubidium

frequency standards in the generation of the color subcarriers, it ap- pears that there is very little degradation of the frequency information

over the 4000-mile microwave path between Boulder and New York.

An important aspect of these results is that the accuracies are orders

of magnitude better than can be obtained with the WWV high-frequency broadcasts and yet they can be obtained essentially for the price

of a TV set. Improved Stability and Accuracy of the NBS Frequency Standard—

As a result of improvements in the stability and reliability of the

NBS-III cesium beam frequency standard, a much improved cali- bration precision has been obtained for measurement periods from

several hours to several weeks. A relative fractional precision was

found to be 1.1 parts in 10^^ for o- (iV=2, t=1 day, T=1 days), based on two months of evaluation of NBS-III versus a commercial cesium

beam frequency standard. An accuracy of 1.5 parts in 10^^ (3cr) is tentatively assigned to the improved NBS-III, based upon the most

recent evaluation.

Improved Timing Using LF and VLF—The usefulness of low fre- quency and very low frequency broadcasts has been improved by a

careful analysis of phase propagation noise. Negative correlation of

phase fluctuations was found between WWVL (20 kHz, Fort Collins,

Colo.) and WWVB (60 kHz, Fort Collins) as monitored in California.

Taking advantage of the negative correlation gave a factor-of-three

improvement in timing. A similar improvement was obtained in a study of NSS (21.4 kHz, Maryland) and WWVL (20 kHz, Colorado). In this case a positive correlation of the phase fluctuations was

found. In addition, the spectral densities of phase fluctuations of the

NSS-WWVL paths and of the two driving oscillators were deter- mined. The corresponding optimum filter was applied to the data;

when used simultaneously with the positive correlation information, a faetor-of-ten improvement in timing was achieved.

Completion of NBS-XIf. Cesium Beam Tube—Construction of the

NBS-X4 beam tube has been completed. Preliminary measurements

indicate that the design goal of a figure of merit of 100 has been realized. (Commercial cesium beams have a figure of merit around 1-4. NBS-III currently operates in the range 5-10.) The beam tube was

jointly constructed by NBS and the Hewlett-Packard Company, and

will be combined with NBS-built electronics to form a much improved

NBS frequency standard with a stability ten times greater than

NBS-III.

Time Scale Coordination luith U.S. Naval Ohservatory—On about

24
1 October 1968, the universal coordinated time (UTC) scales maintained at NBS and the U.S. Naval Observatory were in coincidence.

At zero hours UTC on that date, the rate of UTC (NBS) was raised 4

parts in lO^^ ^^^^j ^i^^ ^.^te of UTC(USNO) was lowered 4 parts in 10^^ in order that the divergence of these time scales would be at a much

slower rate. Portable clock measurements have indicated time syn- chronization of the two scales to within ±5 microseconds, and agree- ments between USNO and NBS will guarantee that both are maintained within this tolerance. The United States thus has, for the first time, a single coordinated time scale jointly maintained by USNO and

NBS.

Temperature

Stability Improvement in Pyrometer Strip Lamps—The major limitation in the calibration of tungsten strip lamps used in optical

pyrometry and radiometry is the instability of the lamps themselves.

A theoretical model has been developed which explains the major fea- tures of these instabilities in terms of the changes that would be ex- pected to occur in the tungsten and lamp envelope due to temperature

changes or prolonged heating at one temperature. This model has been

used as a guide for the construction and heat treatment of 22 strip

lamps. Of these, six exhibit a long-term drift of 0.01 °C in 100 hours,

which is a factor of ten less than the best lamps previously available

;

however, short-term temperature cycling of these lamps produces

changes varying between 0.05 and 0.1°C. Although it may not be

possible to understand and reduce these cycling effects, the lamps will

improve significantly the accuracy of high-precision optical

pyrometers.

Vapor Pressures of the Neons—The vapor pressures of Ne of natural

isotopic composition, ^°Ne and ^^Ne were determined with respect to the NBS-1955 temperature scale from their triple points to their

normal boiling points (about 14.5 to 27 K) . The results for natural neon

were used by the Comite Consultatif de Thermometrie in its assignment of the neon normal boiling point as a defining mixed temperature of the International Practical Temperature Scale of 1968. The

measurements for the pure isotopes are about twice as precise as those

for the natural mixture, where complete isotopic equilibrium possibly

does not exist. Because of the possible variation in the isotopic composition of natural neon (90.92% ^^Ne, 0.257 -^Ne, 8.82 ^^Ne) the most

abundant pure isotope, ^^Ne, is a more practical thermometrie standard.

Superconductor Thermometrie Fixed-Points—A program whose

aims are the extension to lower temperatures of the International Practical Temperature Scale and the development of simple, accurate thermometry techniques has commenced with the examination of the

25
reproducibility on cycling of the superconduction transition breadths

of lead, indium, tin, aluminum, gallium, zinc, and cadmium as meas- ured by magnetic induction. The transition breadths have been compared with the temperature-dependent resistance of doped germanium,

and preliminary results indicate reproducibility in the range of a frac- tion of a fxK (both the doped germanium resistivity and the superconducting transitions).

A-0 Thermometer Bridge—^An improved resistance thermometer

bridge has been developed. A frequency of 400 Hz was chosen for the

bridge so that optimum performance could be obtained using commercially available operational amplifiers and decade voltage dividers.

The bridge resolution is about 20 }xK when used to measure a standard

25 O platinum thermometer at 0°C with a thermometer current of

0.001 A. The bridge enables one to determine the ratio of an unknown

resistor to a standard resistor. The bridge ratio is stable and has such

high accuracy that the measurement accuracy is governed by the reso- lution of the bridge and the accuracy of the standard resistor. To

measure the usual standard platinum resistance thermometer on the new bridge, additional connections are required—a pair of coaxial

leads, which may be as long as 16 meters without affecting the accuracy. Values of resistance determined by this bridge agree with values determined by a high quality DC bridge within the accuracy of the measurements. However, by contrast with DC bridges based on resistor

networks, the ratios are stable without thermostating and do not drift. No lead reversals or auxiliary balances are required with this system,

so that continuous recording of resistance versus time may readily be

made.

High Temperature Thermocouples—The development (supported

by NASA) of reliable high temperature thermocouple probes, which

are being sought for use in the design of nuclear reactors and thermionic devices, requires an understanding of the thermocouple behavior

at very high temperatures in carefully controlled environments. Facilities were constructed for investigating performance of doped W-3 per- cent Ee and undoped W-25 percent Ee thermocouple wires at temperatures of 2400 K and above when the thermocouple wire is subjected to high vacuum, argon and hydrogen environments. The changes in cali- bration of W-3 percent Ee versus W-25 percent Ee thermocouples

vv^ere studied as a function of exposure time in these environments for

time periods of 1 to 1000 hours. In addition, metallographic and chemical analyses were performed to characterize material behavior.

The results in vacuum confirm previous suppositions that evaporative loss of rhenium from the alloys at temperatures above 2200 K

prevents their use as stable thermocouple elements. Stability with time

in the carefully characterized argon and hydrogen environments was

confirmed.

26
One of the more interesting by-products of this work was the dis- covery of extreme ductibility in the recrystallized doped alloy after

lieating in the vacuum environment.

New Temperature Scale—NBS is calibrating thermometers on the

International Practical Temperature Scale of 1968, which was adopted

by the International Committee on Weights and Measures at its meeting in 1968. The Scale replaces the International Practical Temperature Scale of 1948 (amended edition of 1960)

.

Electric Current

Gyromagnetic Ratio of Protons in Water-Surveillance of the NBS

Ampere—The precession frequency of protons in a magnetic field provides a convenient reference for the electrical standards ; however,

fluctuations in the earth's magnetic field are a source of interference.

A self oscillating rubidium magnetometer was set up at a distance

from the proton sample, and phase-locked to a constant frequency

source. The derived correction signal was used to maintain one component of earth's magnetic field essentially constant at both magnetometer and proton sample. Continuous detection of the precession fre- quency by the method of nuclear induction was found to result in

improved convenience and reliability. By using the method of nuclear

induction and compensation for changes in earth's magnetic field, the

center of the proton resonance line can be located with an accuracy of

about 1 part in 10^

Fundamental Physical Constants

Measurement of Optical Frequencies—Modulation of a helium-neon

laser with a 10 GHz microwave frequency has produced sidebands,

V zt (0 (where v is the laser frequency and w is the microwave modulation frequency) yielding about 10^^ photons per second in each sideband for a 1 watt microwave excitation. With the addition of an

optical spatial filter, a Fabry-Perot cavity and servo systems for locking the laser frequency to the Fabry-Perot and the Fabry-Perot to the

microwave frequency, the laser frequency has been locked to the micro- wave frequency with a precision, Sw/w, of about 1 part in 10^. It is hoped that the continuation of these experiments will yield the velocity of light to the accuracy approaching 1 part in 10^ (known at present to 1 part in 10^) and that of light frequencies to 1 part in

10^. The latter can be utilized in problems of standardization of length.

Mechanical Quantities

Microphone Calihration at Infrasonic Frequencies—As a result of

research done at NBS over a period of several years, it is now possible

to calibrate laboratory standard microphones at frequencies down to 375-572—70—3 27
about 1 Hz with good accuracy, and a calibration service will be

offered. This service should be valuable to those concerned with the

measurement of low frequency noises, of which the sonic boom is a prime example.

Precise Measurement in the Medium Vacuum Range—Accurate

measurements in the medium vacuum range provide a firm basis for

extension of measurement reliability into the higher vacuum ranges. These also satisfy a number of technical and scientific needs such as calibration of precision air data computers for high altitude flight and

for atomic collision cross-section studies. Ultrastable vacuum environments and a precision oil manometer allowed absolute measurements

with an uncertainty of 1.2 X 10"* torr + 6 parts in 10^ of the reading

for the range 1 X 10"* to several torr. These procedures have now been

extended with precision mercury columns as reference for intercomparison with the oil manometer and for calibration of certain

transfer gages. Calibration uncertainty in the higher range now ap- pears to be about 4 X 10"^ torr + 4 parts in 10^ of the reading to 25 torr. Hydraulic Research in the United States^ 1968—A new compilation,

summarizing hydraulic research being conducted in university, government, and in industrial laboratories in the United States and Canada was issued as NBS Special Publication 316. This issue summarizes

1,690 research projects reported by 212 laboratories. Compilations of

this nature are very useful in promoting contacts among researchers

in similar areas and in preventing costly duplication of effort. Self-Calihration Procedure for the High Vacuum Range—A major

difficulty in measurements at high vacuums is the lack of a convenient

method for in situ self-calibration of working gages and of a suitable

stable-transfer procedure. Fixed-point processes would be helpful. A

method has been under study utilizing the dissociation of metallic nitrides. Kesults for barium nitride show dissociation pressures ranging

from 2X10-^ torr at a temperature of 740 K to 0.7 torr at 1150 K. The

slope of the In p versus 1/T plot corresponds to an enthalpy of reac- tion of 175 kj/mol N2, which is consistent with dissociation into the

subnitride, BasN, and nitrogen gas. The rate of approach to steadystate pressure is approximately logarithmic with steady values reached

in time of about one hour. The steady-state values of pressures are dependent upon the direction of approach in pressure with the In p

versus 1/T plot parallel but slightly displaced. Pressures are reproducible at present to within 10 percent. Present results suggest that

such a technique may have application in vacuum calibration. Work

toward improved precision and extension to lower pressures is in progress. Automated Vibration Calibration Facility—A facility capable of

calibrating piezoelectric vibration pickups automatically has been

28
developed. It incorporates a small digital computer which controls

the measurement in addition to acquiring the data. The facility makes

it possible to collect considerably more data points than before, and

to perform statistical comparison of the data with the previous cali- bration history of the pickup. The calibration at three times the

number of frequencies can be done in one-third of the time needed

before.

Irrhfroved Transfer Standard Accelerometer—An improved transfer standard accelerometer has been developed for the calibration of

working vibration pickups in or near field locations. These units will

improve field calibrations by permitting the examination of the sev- eral motional components to which the pickups are subjected, thereby

avoiding a common source of error. The transfer standard is unique in two respects relative to commercial units : ( 1

) Instead of a metal housing, it has a ceramic housing

which provides high stiffness, strength, electrical isolation, and substantial weight reduction. (2) Rather than a single pickup for each

acceleration axis, the new unit has three reference pickups mounted

symmetrically about the vertical axis. They make possible a reliable

monitoring of relative motion with respect to phase and amplitude

of points over the shaker table surface. Other design features help to reduce loading effects and to produce a high resonant frequency,

thereby increasing the usefulness of the device. The range of operation

is 10 Hz to 12 kHz at acceleration levels to 100 g and with loads

to 50 g. Strain Measuring Standard for High-Temperature Use—An ex- tensometer for use as a laboratory strain standard which employs a gas-cooled variable capacitor was designed and constructed for the

U.S. Air Force Systems Command. Tests showed it to have a resolution of 0.3 /xm length change over a range of more than 2mm and to operate to at least 1400 °C in a normal atmosphere. A knowledge

of structural strength at elevated temperatures is of urgent importance in the development of gas turbines, rocket engines, missile and

aircraft frames exposed to aerodynamic heating, and components of

nuclear reactors. Misalinement Detector for Axial Loading Fatigue Machines—The

alinement of the grips of an axial-load fatigue machine has a marked

influence on the fatigue life of specimens tested in it. It is not possible to measure these misalinements by ordinary means of linear

measurement. To accomplish the purpose, a compliant element

equipped with strain gages has been developed which is attached to the

machine heads in parallel with the test specimen. As the specimen is cycled slowly through its loading excursion, the detector senses the

minute deflections due to undesirable lateral forces. If these lateral deflections are found to be within allowable limits, the detector may

be removed and the specimen tested in the normal manner. 29
Internal Wave Generation—Under sponsorship of the Office of

Naval Research, a study was made of the internal waves created by

the steady horizontal motion of a sphere through a liquid having

a uniform rate of density increase with depth. A new theory was

developed for this three-dimensional problem which closely approximates the experimental results. Most of the previous work in this area has been restricted to analysis in only two dimensions. Wooden

spheres, having radii from 2.4 to 4 cm, were towed to speeds up to

5 cm per second through fluids having total density differences of

0.9 to 6.7 percent over 50 cm of depth. This permitted a wide variation

in flow parameters without excessive turbulent wake formation and

mixing. The vertical fluid movements, which were only a few milli- . meters, were measured by a wire probe.

In addition to contributing to the understanding of internal wave

generation in the oceans, the new theory will be useful to meteorologists studying the generation and efl^ects of lee waves behind mountains. These are of particular concern to the aviation community,

contributing to the dangerous phenomenon known as clear air turbulence (CAT).

Small-Scale Structure of Turhulence—In collaboration with the

Naval Ship Research and Development Center, and with the partial

support of the Atomic Energy Commission, an experimental investigation of the small-scale structure of a turbulent field was carried out by extending the methods of digital analysis to the measurement of

turbulent velocity derivatives. The statistical behavior of these derivatives was studied in the nearly isotropic decaying turbulence field generated by a 1-inch square mesh grid in the NBS 4i/^-foot wind

tunnel. Higher-order correlations for velocity gradients up to the

eighth order, at two stages of decay, and for a limited change in

Reynolds numbers have been determined. Markedly different from the

turbulent velocities, the higher-even-order correlations of velocity

gradients clearly evidence the departure from a two-dimensional

Gaussian probability distribution, and more clearly exhibit similarity

with a characteristic length or time scale. The results require that current views as to the intermittent character of the small-scale

structure, at least for the Reynolds number range of the present investigation, have to be carefully evaluated. It is expected that investigations of this type, under laboratory-controlled conditions, can play an important role in the understanding of the turbulence structure and

provide insight into closely related problems associated, for example,

with atmospheric turbulence.

Heated-Air Adiahatic Saturation Psychrometer—A humidity-measuring instrument, based on the heated-air adiabatic saturation principle, and suitable for use in both laboratory and field, has been

designed and constructed. With it, the moisture content of atmospheric

30
air can be measured over a mixing ratio range of 0 to 50 g of water

vapor per kilogram of dry air; in terms of dew point, this range is -40 to +40 °C. When compared with the NBS two-pressure humidity

generator over a mixing ratio range of about 2 to 19 g/kg, the mean

difference was 0.046 g/kg and the maximum difference was 0.12 g/kg

;

the corresponding differences in dew point were 0.08 °C and 0.30 °C,

respectively. The instrument is portable and self-contained, requires

a 110-volt, 60-hertz, 2.5-ampere power source, and a barometer. It samples test gas at a gas-flow rate of 4 liters per minute.

Electrical Quantities—D.C. and Low Frequency

Current Transformer Calibration— compact and versatile meas- urement system for calibrating current transformers at power fre- quencies has been developed. The system based on the current comparator principle, permits calibration of all ratios normally

encountered (to a maximum of about 12000/5) , and features the capability of testing transformers at operating currents up to four-timesrated. It provides those laboratories concerned with power and energy

measurements with a method for calibrating their current transformers

to improved accuracies with minimum recourse to the NBS facility.

For transformer ratios up to 1200/5, the measurement accuracy is within 5 ppm for both the ratio factor and phase angle. Calibrations at

ratios greater than 1200/5 are limited by the NBS calibration accuracy

of standard transformers, but can be typically made to 50 ppm or

better. High Voltage Capacitance Bridge—A high-voltage capacitance

bridge based on the current comparator principle has been constructed.

In this bridge a three-winding current transformer or current comparator forms the ratio arms, offering unequaled accuracy, stability,

and sensitivity. In contrast with conventional high-voltage bridges,

the dissipated power is very small and does not affect the accuracy

when capacitors of high volt-ampere rating are measured. With this

bridge, it is possible to calibrate a broad range of capacitors: from

100 pF to several thousand /aF. The voltage range of the bridge is from 100 to 200,000 V, the upper limit depending only on the availability of a high-voltage capacitor. The direct reading accuracy with

which two capacitors can be compared is within 2 ppm for small

ratios and within 10 ppm for the largest ratios (2 X 10^ : 1) . The instrument is designed to calibrate those items which cannot be accommodated on existing NBS low-voltage bridges: high-voltage capacitors

and power factor standards used by the manufacturers of high-voltage

equipment.

International Comparison of Capacitance Standards—Another

comparison circuit of three 10 pF fused silica capacitors has been

completed, this time at laboratories in the Union of South Africa,

31
France, and at the International Bureau of Weights and Measures.

Measurements made at NBS show that the capacitors continue to remain stable to about one part in 10^. Improved Techniques for Audio Frequency Admittance Measurements—A number of bridges suitable for comparing four-terminalpair admittance standards, including a so-called quad bridge for

comparing resistance with capacitive reactance has been developed.

Many simultaneous null conditions must be realized with these bridges,

but suitable techniques have been developed for achieving the re- quired conditions quickly. A reevaluation of the defining conditions

for four-pair standards, and the development of techniques for as- sessing the errors due to insufficient suppression of ground currents with coaxial chokes, have made it possible to reduce the measure- ment errors below one part in 10^. Ne-w Base of Reference for the Yolt \Adofted—On January 1, 1969,

the United States, along with eight other countries, on recommendations of the International Committee on Weights and Measures,

adopted a new base of reference for the volt. In the United States the new base differs from the old base, used prior to January 1, 1969,

by 8.4 parts per million. This means that the electromotive force

(emf ) obtained for a standard cell is now higher than that obtained on the old base of reference by a factor of 1.0000084. The new value

represents a better measurement of voltage in terms of the theoretical

unit of emf derived from the basic mechanical units of length (meter)

,

mass (kilogram), and time (second). This change came about as a

result of absolute measurements made on the ohm and ampere since

January 1, 1948, when the International Committee on Weights and

Measures recommended a conversion from the "international" elec- trical units to the "absolute" system.

CoTivparisons of the Unit of Electromotive Force at BIPM^ NE(\

and NPL—International comparisons of the unit of electromotive

force are made approximately every three years by the Bureau Inter- national des Poids et Mesures (BIPM). Each country participating in the experiment sends a group of saturated standard cells to BIPM,

and on the basis of measurements made at each national laboratory

and BIPM, differences between the units of emf maintained by the

various countries are determined. This comparison usually requires

6 to 8 months to complete. In cooperation with BIPM, the National

Research Council of Canada, and the National Physical Laboratory

of Great Britain, an experiment was conducted in which a group of

saturated standard cells in a temperature-controlled enclosure was

shipped to the various laboratories. A complete experiment between

NBS and the participating laboratory required only 3 to 6 weeks;

the two intercomparisons between NBS and BIPM showed excellent

agreement between the "rapid" and conventional methods. The means 32
of the two rapid intercomparisons differed by 0.2 ppm from the conventional method. Additionally, this excellent agreement serves to verify

the adjustments made to the NBS unit on January 1, 1969. Inductive Voltage Divider—^Aerospace industries require high ac- curacy in the voltage ratio standards used for calibration of guidance

and control equipment. Commercially available inductive voltage

dividers suffer from several limitations, the most serious being the

nonindependence of the corrections to one decade with respect to the

setting of the others. Several single-decade inductive voltage dividers

have been designed, constructed, and cascaded. The results show that

it is entirely feasible to construct multidecade dividers having overall errors two orders of magnitude smaller than the presently available

ones. The single-decade units utilize the multistage voltage trans- former principle and an impedance compensating network, and show

output-to-input voltage ratio errors of approximately 1 part in 10^. Precise EMF'^s from the Microwave Josephson Effect—Instrumentation has been developed for the precise comparison of standard cell voltages with the emf's produced by microwave Josephson junctions

operating at a temperature of two kelvins. These junctions act as very

precise frequency-to-voltage converters making possible the translation of standards of radio frequency into independent, nonelectrochemical sources of d-c electromotive force. High-Intensity Electric Field Measurements—An electro-optical

technique which utilizes laser light for analysis of high-intensity

The electromagnetic field within a Kerr cell is rendered visible through use of polarized laser light. A typical fringe pattern is shown in the insert. 33
electrostatic fields has been developed and used for the measurement

of distorted fields obtained when high direct voltages (to 90 kV) are applied to nitrobenzene-filled Kerr cells. The field can be mapped

from fringes produced by the Kerr effect. This technique, which was

developed to permit calibrations of Kerr pulse-measuring systems,

offers several advantages over conventional field-mapping techniques,

including the following: (1) the two-dimensional visual images,

similar to those achieved in photoelastic mechanical stress analysis,

permit direct observation of the field distribution, thereby enabling

immediate detection of regions of high electrical stress; (2) space- resolved measurements of field strength and potential are obtained

from a single photograph; (3) measurement resolution increases with

the magnitude of the field; and (4) a laser source allows simplicity in

the optical system. It is anticipated that this technique will also be

useful in electrical stress and breakdown studies, in high-intensity

field-mapping experiments, and in investigating the behavior of many

dielectric liquids.

High-Voltage Pulse Measurements System— system which generates and measures high-voltage pulses (rise-time ^ 1 /xs, duration ^

4: fis) has been designed and constructed. This system, which received

partial support from the Atomic Energy Commission through the

Sandia Corporation of Albuquerque, New Mexico, is equipped for

time-resolved, simultaneous, voltage divider and Kerr electro-optical

measurements of pulses peaking between 5 and 300 kY.

Electrical Quantities—Radio Frequency

High-Frequency Region

Design Data for Impedam.ce Standards—NBS uses quarter-wavelength short-circuited sections of waveguide as reference standards

for calibrating microwave impedance standards. These waveguides

can be accurately evaluated and have the additional advantage that

losses at the place of connection are negligible. In order to make these

reference standards more available to other laboratories, design data

have now been published. The data consist of a series of computercalculated curves of return loss versus frequency for each of the

standard sizes of rectangular waveguide and coaxial line presently in

use. The curves are normalized to a conductivity of 10^ mhos/meter

and can be read to ±2 percent, which gives sufficient accuracy for many

purposes. In case greater accuracy is required, formulas are given

for the calculation of return loss. Using these data, any interested lab- oratory can design and construct accurate impedance standards and

improve the accuracy of their impedance measurements.

Primary Standard Coaxial Noise Generators—Two precision, coaxial, thermal noise generators were designed and constructed for use as primary standards of noise power in the high-frequency range. 34
Precision coaxial thermal noise generatx)TS for use as primary noise power

standards at frequencies from 3 to 100 MHz.

At present both operate at either 30 MHz or 60 MHz, but they can be

modified to operate at any frequency between 3 and 100 MHz. One

generator, using a bath of liquid nitrogen, has a noise temperature of

approximately 76 K with an uncertainty of 0.10 K. The other, using a bath of heated fluorochemical liquid, has a noise temperature that is adjustable between 300 K and 500 K with an uncertainty of 0.15 K.

These standards are used to measure high frequency random noise sources having temperatures between 75 K and 30,000 K.

Basel)and Pulse Transmission—Frequency and time domain analyses

of normally conducting coaxial cables at low temperatures have been

performed. The anomalous and classical skin effects were considered by

employing the Renter and Sondheimer anomalous skin effect theory.

Frequency and time domain response versus temperature (4 to 300

K) has been predicted for six miniature commercial coaxial cables and

one Nb-Pb superconductive cable maintained in the normal state. Grood

agreement was obtained with available time domain data, both directly

and by application of Fourier transform techniques. The methods

developed in this work provide a means for computing transmission

characteristics in the presence of temperature gradients along a coaxial

cable such as would be encountered between a cryogenic environment

35
and ambient space. From this information, pulse distortion in the cable can be predicted. Similarly, this technique can be used as a means for

pulse shaping to predetermined requirements.

Improved Pulse Power Meters—NBS has been instrumental in the

recent commercial development and manufacture of three improved

E-F pulse power meters. The Bureau's role consisted mainly of pointing

out the need to industry and providing technical consultation. The

uncertainty limit in all three instruments is 5 percent (0.25 dB) as compared to 10 percent previously. The need for improved accuracy in

RF pulse power measurements has resulted from recent changes in

DoD and FAA specifications for Airborne Tactical Air Navigation

(TACAN) and radar altimeter equipment. These changes were designed to improve the accuracy and reliability of airborne systems vital to the safe operation of military and civilian aircraft. The new meters

have been evaluated at NBS and are available for purchase on the

open market.

Microwave Region

Development of Microwave Noise Standards—A new mechanism

for describing and evaluating performance parameters in microwave

systems has been developed. This description is based on "power

equations" instead of microwave circuitry. As suggested by the terminology, the fundamental parameter is the net power flowing across the terminal surface; thus, the new technique requires only a single

scalar parameter, while providing a systematic and unified approach

to the mismatch error problem. It also incldes simplified techniques

for evaluating mismatch corrections, and because the description is based on "terminal invariant" parameters, the uniform waveguide

and precision connector requirement is eliminated for an important

class of practical measurement problems.

Development of Millimeter Wave Standards—The conventional

microwave approach to component design begins to break down at milimeter wavelengths because of difficulties in achieving precise dimensions and tolerances and because of unacceptable losses and limited

power-handling capabilities. It is currently thought that development

of standards at these wavelengths will require the use of electronic

components based on quasi-optical principles. As part of a new NBS

effort in the area, a circular polarizer and a turnstile junction were

built and evaluated. Their design was based on an optical principle

not previously applied to components at millimeter wavelengths.

Successful operation of the components has broadened the base of tech- nology available for the development of millimeter wave standards.

Precision Microioave Power Measuring System—Power is a fundamental quantity in microwave equipment design and testing. Highly

accurate measurements can now be made with new d-c substitution

techniques using a bolometric detector in a bridge arrangement. This

36
system is an improvement over the original self-balancing d-c bridge

developed at NBS in 1956 and used extensively by standards laboratories throughout the country. The new system will find even wider

acceptance because it permits improved accuracy at the field level. In

addition, there is a reduction of cost by a factor of seven, and reduction

of weight by a factor of twenty. The system, which is completely

solid state, also functions as a precision power leveller, a 0-10 V differ- ential voltmeter, and an ultrastable 0-10 V power supply. This combination of features permits the measurement of r-f power levels of the order of 10 mW without accessory slidewire potentiometers or

digital voltmeters.

Joseplison-Effect Studies—Experiments were undertaken to determine the maximum frequency at which Josephson-effect oscillations

could be observed in superconducting point contacts. Earlier work

in this field was limited to photon energies below or near the energy

gap of the superconductor, since it was generally believed that significantly higher frequencies would not be observable. Quite to the contrary, oscillations were detected at frequencies as high at 8200 GHz

a photon energy of approximately 12 times the energy gap. These

results are significant both for the theory of superconductivity and

because they indicate that Josephson junctions may be useful as detectors, harmonic generators, mixers and spectrum analyzers in the

infrared, where few other coherent devices are available.

Photometric and Radiometric Quantities

Effect of Loiuering Size and Brightness on Color Discrimmation—

The ability to discriminate between colors becomes poorer when the

brightness is lowered or the size of the target is decreased. The loss in

color discriminability is more marked for blue-yellow differences than

for red-green differences. This phenomenon has long been known in

color signalling, such as in the railroading and lighthouse services,

where it is generally understood that pur^^le, blue and yellow can not

safely be used for signal lights that must be identified at a distance.

As the distance from the observer to the target is increased, the visual

size of the target decreases, and a loss in color discriminability results. A study has been made of the relation between size and brightness for

a given loss in discriminability. This study indicates that decreases in

size of target can be compensated by increase in brightness. Conversely, low levels of brightness can be compensated by an appropriate

increase in target size. The appropriate increases were also determined

and were found to be systematic.

Theory of Perceived Size of Color Differences—Because of industrial need of a mathematical basis for setting color tolerances, several

approximate measures of perceived size of color differences have been

developed empirically. One of these is based on distance on the CIE

37
1960 UCS diagram, so-called because it was recommended by the International Commission on Illumination (CIE) in 1960 as yielding an approach to uniform chromaticity spacing. Current studies at NBS

have shown that this diagram can be derived from the second stage of

the Miiller theory of vision. This second stage treats normal vision as a combination of protanopic (yellow-blue) vision with tritanopic (redgreen) vision. This view implies that the true measure of color dif- ference is not distance on the CIE 1960 UCS diagram, but rather the

angles between the protanopic confusion lines on this diagram for

amount of yellow-blue difference, and those between tritanopic for

red-green. This theoretical measure checks out well for differences

between the various colors of the spectrum, and is being checked now

for other colors. The Ideal Lovihond Color System—The Lovibond System of red,

yellow, and blue glasses has been used for many years for the grading

of transparent materials. The color scales of the system were calibrated

in arbitrary units with the three units related in such a way that for

daylight illumination a combination of one unit eadh of the red, yellow,

and blue glasses results in an approximately neutral filter. In 1962,

ideal units of the three filters were defined and colorimetric coordinates were determined, in accord with the 1931 (International Commission on Illmnination) standard observ^er and coordinate system, for

multiples of the unit filters and various two-filter combinations of

them. These 1962 determinations were made only for tungsten illumination of the filters (Illuminant A). Calculations of the chromaticity

coordinates have now been made of the same combinations of the unit

filters, for daylight illumination (Illuminant C). In 1960 and in 1964,

the CIE recommended the use of two transformations of the original

1931 coordinate system yielding improved uniformity of spacing. The

chromaticity data of the Lovibond System have now been computed

for both Illmninants A and C, in terms of both the 1960 {u^v) - and the

1964 (?7*,F*,TF*) -transformations of the 1931 (X,r,Z) -coordinate

system. These tabulations enable convenient expression of uniform

color tolerances in terms of Loviboind glasses.

Spectromdiometric Photometry—^A procedure has made it possible

for the first time to calibrate with reasonable accuracy the lumen out- put of a light source of any spectral distribution by means of in- candescent standards. The method is based on a comparison of flux from the lamp to be tested with that from an incandescent standard

at each wavelength interval of the visible spectrum. A set of 40 W

cool-white fluorescent lamps was calibrated with this instrument and

made available to the lamp industry through a commercial testing

laboratory. An industry-Avide intercomparison of 40 W cool-white and

daylight fluorescent lamps was set up and preliminary results are now

available. Although substantial progress has been made toward con- 38
sistent spectroradiometric measurements throughout the industry,

further work Avill be necessary before the measurement system can be

considered completely satisfactory.

Standard Detectors for the Vacuum Ultraviolet— investigation

of the day-to-day reproducibility of the photoelectron yield of several

materials—Au, W, AI2O3 on Al, Co, Al—suitable for use as the cathode of a windowless diode has continued. Detectors of this type could

serve as standards for wavelengths less than 105 nm, where durable

window materials do not exist. Preliminary results indicate that cer- tain materials—AI2O3 on Al, Au—under prescribed conditions of

measurement and storage, exhibit reproducibilities of photoelectron

yield of better than 5 percent. Windowed, evacuated diodes are being

investigated for use at wavelengths longer than 105 nm. Early results indicate excellent stability of calibration—with reproducibility better

than 5 percent—is possible in this region.

Laser Poioer Measurements—Using a laser calorimeter with a timed

shutter (developed at NBS for pulsed laser energy measurement),

techniques have been developed to measure the average powder of CW

lasers in the wavelength range of 450.0 to 1060.0 nm. CW powermeasuring devices may be intercompared with a ±4,0 percent accu- racy by using comparison techniques similar to pulsed energy measurements. Also, a power meter was developed which is capable of

measuring the power of a 200 W CW CO2 laser with an accuracy of

±4 percent. The laser beam is absorbed in a hollow, blackened copper

cone through which water flows at a known rate. The measured temperature rise and the rate of flow give the power of the laser. The

range of the meter was estimated to be from 1 W to well over 10 kW

;

however, NBS at present does not possess lasers with powers to test the full range of the meters. PHYSICAL PROPERTIES

Approximately half of the activity within the Institute for Basic

Standards is related to the measurement of physical properties of

well-defined substances. The rapid growth of the physical sciences has

provided scientists with many new techniques for measuring "old"

physical properties and has made accessible many new ones. With new

techniques it has been possible to increase the precision of measurement, provide the scientific community with a greater range of ref- erence data, and characterize certain processes more fully. Examples

of these activities, drawn from current work, are given below.

Atomic and Molecular Properties

Radio Line Spectra of OIL—During January and February of

1968, precision measurements were made, of the radio line spectra of

39
two excited states of the OH molecule, at the request of Harvard radio astronomers. Current theories of the excitation conditions of interstellar OH gas involve these two states, and the Harvard astronomers were about to make a sky search for the corresponding line radiations,

using the large radio telescope at the National Radio Astronomical

Observatory at Greenbank, West Virginia. Provided with laboratory

measurements accurate to within 1 ppm, the Harvard scientists tuned

their telescope to the correct frequencies and were able to detect faint

OH signals in a single night of observation. Without the NBS measurements, the search might have failed or might have required a great

deal more telescope time and expense. Departure from EqwilibmuiTh in a Nitrogen Arc—Although previous

studies of sources similar to the atmospheric nitrogen arc had not

revealed departures from local thermodynamic equilibrium (LTE),

the availability of improved experimental techniques made the

reexamination of this source attractive. Absolute intensity measure- ments were made on various atomic and molecular spectroscopic fea- tures produced in an atmospheric-pressure nitrogen arc operating at temperatures from 5,000 to 15,000 K. The relationships among the

intensities of these spectral features were then compared with the

corresponding relationships among the upper-state populations in

LTE in order to obtain optical transition probabilities and reveal

departures from equilibrium. The data from the N i and N ii lines were

consistent with the existence of LTE above 11,000 K and recently published transition probabilities. On the other hand, no choice of transition probabilities for or No bands resulted in agreement between

the experimental data and LTE calculations below 10,000 K.

Arc Measurement of Some Am Optical Transition Prolyahilities—

In recent years, many efforts have been made to measure or calculate

transition probabilities and related quantities for the strong lines in

the visible spectrum of Ar ii. While two recent sets of lifetime measure- ments show good agreement with each other, results derived from

theoretical calculations and emission measurements exhibit disagreement as large as a factor of two. Emission measurements leading to the

determination of more than 100 Ar ii transition probabilities were made in the hope of reducing the uncertainty attached to some of

these values. Measurements were made in a wall-stabilized, atmospheric-pressure argon arc and transition probabilities obtained using

the generalized Fowler-Milne technique. Transition probabilities,

having an estimated uncertainty of 10 percent for the best cases, for

all lines of the 4s-4^ and ?>cl^f Ar ii arrays lying below 7200 A.

Where comparison with lifetime measurements was possible, the agree- ment was satisfactory.

Yibration-Rotation Hamiltonian for Triatomic Molecules—Two

conventional theoretical formalisms exist for the vibration-rotation

40
problem in triatomic molecules : one appropriate for linear molecules,

having four vibrational and two rotational degrees of freedom; the

other appropriate for bent molecules, having three vibrational and

three rotational degrees of freedom. In the present work, a single,

unified formalism was developed, applicable to both cases. The unified

formalism has two vibrational and three rotational degrees of freedom.

The remaining degree of freedom, corresponding to the bending vibration, is singled out for special treatment. Among other things, an exact quantum mechanical vibration-rotation Hamiltonian was derived; a

slightly modified ro matrix formalism for the stretching vibrations was introduced ; and the dependence of the rotational constant on the

bending vibrational quantum number was determined. The formalism was applied to experimental data for HCN/DCN, H2O/D2O, and

CsOH/CsOD. It displayed distinct advantages in the HCN/DCN case. Atomic Spectra—New energy levels have been found for atoms or

ions of Tc, W, CI, Y, La, Pr, Pm, Tm, and Th. These theoretical calculations have aided in the interpretation of many of these new levels, as well as in electron configurations in K, Cu, Zn, Ag, Cd, and Tl. Such

analyses of optical spectra are useful for interpreting astronomical

and plasma spectra, predicting thermodynamic and chemical properties, and for solid state and atomic physics.

Accv/rate Reference Wavelengths in the Optical Region—New

measurements and application of the Eitz principle have yielded 1,670

improved wavelengths in the thorium spectrum from 2600 A to 13,000

A. The uncertainty ranges from 0.0002 A for the shorter wavelengths

to 0.002 A at the long wavelengths. Similar work gave over 500 wavelengths for krypton 86 (the spectrum containing the primary standard

of length), accurate to ±0.0001 A at the short wavelengths (3400 A)

and to ±0.01 A at the longest wavelengths (4/>im) . A list of almost 2,200 vacuum-ultraviolet wavelengths accurate to ±0.002 A or better has

been compiled for the region 300-2000 A. This list contains many lines

(belonging to frequently observed spectra) measured at NBS to ±0.0005 A.

Torsional and Ring Strain Forces in Molecules—Studies have re- cently been made to determine the structures of a series of small, ringshaped molecules: silacyclopentane ; 2,5-dihydiothiophene; 2,3-dihydiothiophene ; silacyclopentane; and cyclopentene oxide. These

molecules are of particular interest to theoretical chemists because the

precise shape of the ring is determined by a delicate balance between

ring strain forces, which tend to make the ring planar, and torsional

forces between hydrogen atoms attached to adjacent carbon atoms. The

torsional forces act to pucker the ring into a nonplanar conformation.

These two types of forces are also important for a number of large biologically active molecules. Before such large molecules can be under41
stood, however, we must be able to understand small molecules, which

are easier to study. By studying certain low-frequency vibrations of

these molecules by far infrared or by microwave techniques, the details

of the forces controlling the ring structure in these molecules can be

determined.

Plane Grating Spectrograph—A new plane grating spectrograph

combining speed with high resolution has been constructed. It is being

used to photograph spectra of atoms and molecules with resolving

powers (greater than 5 X 10^) not previously available in grating in- struments at NBS. The general optical design is a modification of the

two-mirror Czerny-Turner arrangement with a focal length of 3.34 m. The line definition was improved by increasing the focal length of the

collimating mirror and positioning the slit very close to the photographic plate.

Transition Pro!)ability Measurements in the Neutral Argon Spectrum—Numerous recent determinations of transition probabilities of

neutral argon are indicative of the importance of this noble gas in

high-temperature technology. Nevertheless, serious discrepancies be- tween the various experimental and theoretical results have remained.

Therefore, two independent measurements and an extensive analysis of

all other work on the argon spectrum have been performed to clarify

this situation. The two experiments were, first, lifetime determinations

of the prominent 5p states with a delayed coincidence apparatus, and,

second, emission measurements of 80 infrared lines with a wall-stabilized arc. A number of the transitions measured with the arc originate

from the ^p states so that they could be linked up with the lifetime

results as well as some other arc data obtained at NBS to determine

the internal consistency of all measured values. With this combined

effort a reliable set of transition probabilities for the more prominent

argon lines has been established.

Photodetachment Studies—Photodetachment studies on the ion

(H2O) OH" have shown that this ion may play an important role in

controlling electron densities in the D region of the earth's upper atmosphere and lower ionosphere. In this work, photodetachment has been

observed to take place only in the ultraviolet and deep violet region of

the spectrum : most visible radiation will not detach the most weakly

bound electron from this ion. The observed spectrum indicates that

the H2O—OH" bond is relatively weak (<1 eV). Thus the relatively

large photodetachment cross section (<10-^^ cm^) at short wavelengths

may be accompanied by a large photodissociation cross section in the

infrared region.

Photodetachment studies of S~ have provided for the first time an absolute cross section 2 X 10^^~ cm^, and a more precise value of the

electron affinity, 2.095 zb 0.015 eV. This work also indicates that the

previous application of threshold behavior theory is probably less exact than had been generally believed.

42
Compilation of Volume II of Critically Evaluated Data in Atomic

Transition Prohabilities {Elements Na through 6"^)—The critical evaluation of atomic transition probability data for the second 10

elements of the periodic system (Na through Ca) has been completed

and the tables have been published as part of the NSRDS-NBS series. Numerical "best" values for approximately 5,000 transitions, both

allowed and forbidden, have been tabulated and for each value an

estimated uncertainty has been given. The bulk of the data is estimated

to be accurate within 50 percent. The best accuracy is 3 percent for the

famous sodium D- lines. The compilation contains many original data

which were obtained by numerical applications of the coulomb

approximation and by utilizing the systematic trends of oscillator

strengths within isoelectronic sequences. Continuous Emission from a Hydrogen Plasma—The continuous

emission from a hydrogen arc plasma has been extensively investigated

theoretically as well as experimentally. The continuum studies are of considerable interest primarily because the hydrogen continuum

has great potential to become one of the principal spectral radiation

standards in the near ultraviolet and vacuum ultraviolet where no

established radiation standard exists as yet. Computer calculations

of the continuous emission have been performed over an extended

range of temperature encountered in arc operations. The contributions from the hydrogen negative ion (H~) and the hydrogen molecular ion (Ha^) have been included, using recently calculated absorption

coefficients, and the contributions of the extended line wings of the

hydrogen lines have been considered for the first time. Intensity

measurements with a pure hydrogen arc carried out at 13,000 K show

that the relative spectral continuum distribution in the observed

range from 2,800 to 6,000 A follows the calculations within a few

percent. However, the measured continuum is stronger by about 15

percent than the calculated one on an absolute scale. Some of the

likely causes of this disagreement, like small deviations from thermodynamic equilibrium in the arc, are currently being investigated.

Microwave Spectra of Free Radicals—The microwave spectra of

BrO and SFs have been observed for the first time. Transitions from

the ^113/2 state in BrO were detected, but not from the ^Ili/a state. The

observed data for this molecule led to a rotational constant, hyperfine

parameters, and nuclear quadrupole constants. Observation of the

spectrum of SF2 was of particular interest, since the chemical litera- ture contains meager and conflicting reports of attempts to synthesize

the molecule. The observed data for this molecule led to rotational

constants, a dipole moment, and a prediction (with the help of a complete centrifugal distortion analysis) of the molecular force constants and infrared spectrum.

375-572:—70-I 4 43
Analysis of Oj^tical and Electron Scattering Data—A procedure

has been developed to improve the analysis of optical- and inelastic- electron-scattering data. A least-squares computer program has been

used to check the mutual consistency of models for the complex

frequency-dependent dielectric constant (for example, the DrudeLorentz model) and of different types of experimental data (for

example, reflectance and inelastic electron scattering cross sections)

for a number of elements (Al, Cu, Be, Ge, Sb, Bi, Na, and K) within

the accuracy of measurement. The model parameters from satisfactory

fits can be used for the identification of structure for comparison

with theory, and to derive optical constants. In deriving optical constants from ultraviolet reflectance measurements, for example, the

present approach obviates the necessity for arbitrary extrapolations

of normal-incidence data, and better precision can be obtained than

in the conventional analyses of data obtained at multiple angles of

incidence.

Laser Electron Paramagnetic Resonance—A new technique involving an HON laser in EPR was developed and given the name LEPR

(Laser Electron Paramagnetic Resonance). This technique involves

focusing the beam of the HCN laser on a small hole in the mirror of

a Fabry-Perot interferometer centered in a uniform external magnetic

field. The radiation is monitored by a Golay cell through a small hole

in the opposite side of the interferometer. The output of the cell

is connected to a 13.5 Hz phase detector referenced to the modulation of the magnetic field. A few torr of oxygen gas is placed in the

Fabry-Perot, and the magnetic field is swept. Any absorption of

energy by the oxygen gas is detected by the Golay cell. Using this

technique, five lines in oxygen were observed. Considerable improveSample cell used in laser EPIl studies of oxygen Iiim - <»l)-frvedj and NO2

(over 200 lines observed).

44
ment was achieved by making the oxygen absorption cell part of

the laser and employing a Brewster window between the HCN and

oxygen to determine the polarization of the radiation. With the

improved sensitivity, a total of 12 lines has been observed and

identified, and further improvements are planned. The spectrum of

NO2 is also being taken ; thus far, over 200 lines have been observed.

Electron Density Measurements—The abnormal negative glow

plasma in helium has been adapted for a thorough investigation of the

microwave cavity technique used to measure the electron density in

plasmas. This negative glow plasma, in combination with a low fre- quency microwave cavity, was used for experimental and theoretical

investigations of the influence of longitudinal modes on the microwave

measurements. A double perturbation technique allows for evaluation

of the microwave field within the plasma and an extension of the

cavity measurements beyond the limits of the simple perturbation

method. Data indicate that use of the microwave technique, as interpreted by the simple perturbation theory, is more limited than com- monly thought, due to the presence of excited longitudinal modes not

accounted for by the theory. The double perturbation technique has

in some situations extended the limits for the measurable electron

density by about 1-2 orders of magnitude.

Heat Pipe Oven—A new, well-defined metal vapor device called

the heat pipe oven has been developed for spectroscopic measurement.

Based on a heat conductive element first developed at the Los Alamos

Scientific Laboratories, the oven continuously generates homogeneous

vapors of well-defined temperature, pressure, and optical path length.

All three parameters can be measured directly with high accuracy. The

vapor is confined by inert gas boundaries which remove the window

problem and allow a direct pressure measurement without relying on vapor pressure curves. As such, the heat pipe oven is suitable for use

in connection with vacuum UV spectrometers. It has already been

used successfully in a number of different spectroscopic measurements

(line broadening, transition probabilities, cross sections, etc.) and has

been applied to the generation of metal vapor plasmas.

Line Broadening Theory—A new theoretical treatment of spectral

line shapes emitted by plasmas has been developed. This approach,

called the unified theory, provides the first line-shape theory capable

of describing a line profile from the line center to the quasi-static

wings. Calculations of the Lyman a line of hydrogen have been made

and compared with experimental results and other theories. The

calculations provide the first accurate description of the transition

from Markovian to non-Markovian electron broadening. This approach

should provide a strong foundation on which further investigations

of line shape phenomena can be based.

45
A modified lieat-pipe oven (left) is here being used in spectroscopic investigations.

Electron Impact Cross-Section Data Bank—A data bank containing

evaluated experimental cross sections for low-energy electron impact on atoms and small molecules is now active. Data are gathered on a regular basis from the current scientific literature. Graphical display on microfilm can be prepared from the cathode ray tube used as a computer output device. This system Avill allow fast resopnse to re- quests for the latest evaluated cross-section data and makes possible

the updating of hard copy on a regular basis. Dissociative Processes of Simj)le Molecules—An apparatus has been

constructed to measure the angular and energy distributions of energetic ions produced by electron impact on molecules. Ion counting is used so that the processes can be observed near threshold where cross

sections are small. Initial work on the energy and angular distribution

of protons from H2 has yielded a direct measurement of the momentum

transferred to the molecule center of mass in the ionization process. This is the first such measurement and will provide theorists interested

in the ionization process near threshold with some valuable checks on their theories. This work has also shown that the angular distribu46
tion of protons near threshold is not a pure cosine-squared distribution, but contains an isotropic part which may be due to autoionizing

states of H2. After subtracting out the isotropic part, the resulting

angular distribution seems to fit a more complicated function as pre- dicted in a recent calculation.

Dissociation Energy of lA^ from Laser-Excited Fluorescene—A new

value for the dissociation energy (bond strengtih) of the Lis molecule

has been established. This was accomijlishecl by analyzing the fluores- cence excited in the ^Lis, ®Li^Li and ^Lis molecules by various lines of

the argon ion laser. The fluorescent light was dispersed using a %-meter

spectrometer. A Birge-Sponer extrapolation of the G('y) values gave

Do°= 1.026 ±0.006 eV. This value, combined with the dissociation limit

of the upper state previously determined by Loomis and Nusbaum,

proves that there is a potential maximum of about 0.12 eV above the

asymptote of the potential curve for the Lis B state. Experimental

determination of the magnitude of the potential barrier for this fundamental molecule should serve as a useful check on various theoretical

calculations of the interactions between atoms at intermediate

distances.

Solid State Properties

Thermal Expansion of Platinum—The linear thermal expansion of

two specimens of platinum has been measured with a high-precision

optical comparator 'between 1000 and 1900 K. These data are believed

to be accurate to 30 ppm for this material in the hi^h-temperature

range and will be very useful since platinum is widely used as a ref- erence material for calibrating dilatometers and x-ray diffraction

equipment.

Photoelectron Emission from Tungsten in the Vacuum Ultraviolet—

Studies of the effects of adsorbed gases on the photoelectron emission

from tungsten have shown the electron yield to be very sensitive to even partial monolayer coverages. Over a range of photon energies

from 7.7 to 21.2 eV, each of the gases H2, N2, 0., CO, CO2, NH3, and

H2O produced specific yield changes which were dependent upon the

species and quantity of gas adsorbed. The behavior of the electron

yield during adsorption can be qualitatively correlated with work

function changes, and also offers evidence for the appearance of additional electron emission produced by photoionization of the adsorbed

gas.Baseband Pulse Delay Lines—A miniature 50-n superconducting

coaxial line (80 feet long, Nb inner conductor O.Ol^O.D., Pb outer con- ductor 0.034" I.D., PTFE dielectric) has been analyzed in terms of

the complete Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity. The results have been compared with those based on the

47
two-fluid superconductivity model. The surface impedance of both

superconductors, the line attenuation, and the picosecond time domain

step responses have been calculated for a temperature of 4.24: K. Pre- liminary results indicate that with appropriate parameter values, the more tractable two-fluid model is adequate for engineering design considerations up to and including microwave frequencies. For higher

frequencies, i.e., energies approaching or beyond the BCS energy gap,

the complete BCS theory is required.

LoiD-Temperature Thermal Expansion—^^The low-temperature

thermal expansion of over 30 aluminum, nickel, copper, and iron-base

alloys was measured from liquid hydrogen temperature (20 K) to room temperature. Both the thermal contraction from room temperature and the thermal expansion coefficient were tabulated as a function

of temperature. Comparison of similar alloys and alloy conditions led

to the general conclusions that : ( a ) relatively large changes in composition are required to produce significant changes in thermal expansion, (b) thermal treatment or condition has little effect except when

it produces a basic structure change, and (c) the thermal expansion

coefficient at room temperature is a good indicator of the total length

change that occurs as alloys are cooled. Improved Superconductive Tunnel Junctions—A new method of

fabricating tunnel j mictions between superconductive niobium and

lead films has been developed. The method consists of condensing the

products of a glow discharge onto the surface of a cold (80 K) niobium

film, followed by a thermal cycle and deposition of the lead film. This

method gives a very high yield ( '^60%) of tumiel junctions with very

low leakage current. After coating with a plastic layer to protect the

film, these jimotions become very rugged. They may be stored at ambient temperature, exposed to the atmosphere for many months,

and subjected for many hundreds of cycles to a low temperature without detectable deterioration. They represent a significant step towards

the fabrication of permanent instruments employing the Josephson

effect. Development of Super-Punty Alummum—Design and construction

of cryogenic aluminum magnets has been hindered in the past by the

lack of large amounts of high-purity aluminum. Two years ago the

highest purity available (99.9999) had residual resistance ratios of

only 2,000 to 4,000. Now, through cooperation between NBS and in- dustry, aluminum of the highest known purity, having residual re- sistance ratios of up to 45,000, has been produced. It is expected to be

extremely valuable in physical and mechanical property measurements, as well as for potential use in magnets and other commercial

applications.

48
Thermodynamic and Transport Properties

Determination of the Second Virial Coefficients cmd Intennolecular

Potential for Several Important Gases—Methods developed for the

optimum determination of virial coefficients and intermolecular potential functions from experimental data have been applied to the litera- ture for the 14 important gases (Ar, Xe, Kr, He, Ho, No, Air, Ne, O2,

D2, H2O, D2O, CH4, CO2) . Tables of second virial coefficients and their

first and second derivatives as well as intermolecular potential parameters, and third virials have been produced. These second virial coeffi- cients and their derivatives are sufficient for the calculation of the

real-gas corrections to the ideal-gas equation of state in many technical

applications. The intermolecular potential functions can be used as input data in a variety of microscopic theories for macroscopic quantities. These tables represent a considerable improvement over those

generally available previously.

Precise Experimental Determination of the Vapor Pressure of CO2

to Within Several Hundredths of a Degree of the Critical Point—The

vapor pressure of CO2 has been measured with a temperature precision

of 0.001° C and a pressure precision of 0.001 bar to within 0.001° C

of the critical point. The data have been fitted to a nonanalytic equation

consistent with the scaling-law approach. The usual analytic vapor

pressure equation is based on the Clausius-Clapeyron equation, and

contains the assumption that the liquid specific volume can be neglected

with respect to the vapor specific volume, an assumption clearly in error at the critical point where both volumes are equal ; thus, its fit exhibits systematic deviations near the critical point. The new equation produces a fit with a standard error an order of magnitude

less than that of the analytic equation, and no systematic trend in its deviations.

Bose-Einstein Condensation—The condensation of an ideal BoseEinstein system was studied using an approach in which the Bose

transition acquires a very close resemblance to the second-order transitions about the liquid-vapor and magnetic critical points. The system

exhibits an appropriate macroscopic order parameter related to the

conjugate field through an ordered sequence of terms in reduced

thermodynamic variables. In the vicinity of the transition, the equation of state takes on the homogeneous functional form predicted by

the scaling hypothesis and exhibits a power-law behavior with nonclassical exponents. The various ordered correlation functions

(thermal expectation value for the various ordered products of Boson

field operators) were determined and used to demonstrate the existence

of a "critical eigenvector" conjectured by Green as a universal feature

of critical points. An extension of certain properties of this simple

49
model has also proven useful in understanding the hydrodynamics of a superfluid condensate.

Determination of the Sensitivity of Therinodynamic and Tramport

Properties to the Intennolecular Potential Function—The simultane- ous fit of equilibrium and transport properties has been assumed to be

a particularly sensitive method for the determination of potential

functions, as has the isotopic thermal diffusion ratio. Both have been

examined for their inherent sensitivity to the potential function.

Results reinforce those obtained for the individual properties and

show that no new information can be obtained, in principle, from the

requirement of a simultaneous fit to pairs of properties. A method for

the testing of a functional form of an intermolecular potential function by the simultaneous fit pairs of properties was developed.

The isotopic thermal diffusion factor has never been j)roperly studied

because of the large uncertainties present in such data. It has now

been confirmed that the isotopic thermal diffusion factor can be a very

sensitive probe of the potential function provided measurements are made at temperatures outside an insensitive temperature range. Unfortunately much existing data were taken precisely at temperatures

inside this insensitive range. The experimenter can now avoid such

design errors in the future by choosing temperatures consistent with

our results. The insensitive temperature range, 0.6<T/Tb<1.2 where

Tb is the Boyle temperature, was found to be essentially that found

for other transport properties previously studied.

Analysis of PYT Data Obtained With Burnett Apparatus—In

1936, Burnett described a simplified technique for the measurement

of the isothermal compressibility factor of a gas. The parameters

necessary for this method are pressure and temperature, eliminating

the troublesome volume measurement; however, a nonlinear statis- tical problem must be solved to evaluate the compressibility factor as a function of pressure. Many different data-reduction schemes have

been developed for the evaluation of the virial coefficients and the

compressibility factor, each differing in its approach to uncertainties

involved. A meeting on the Burnett data-reducing problem was held

at NBS, focusing on particular problem areas, and resulting in close cooperation among several laboratories. A round-robin problem was

designed and circulated, and the comparison of the various data

analyses is being used to define the areas of disagreement. This ap- proach, established as a result of the meeting, will permit increased

use of an experimentally simple method.

Development of a Method for Optimizing the Coefficients Determined from Measured Data Fitted to a Power SeHes for an Experiment of a Given Precision—In calculating the coefficients of a power

series fitted to experimental data, several factors besides experimental

precision affect the standard error of these coefficients. Using the prin50
ciples of statistical analysis, the effects of factors such as interval

size, extrapolation, number, relative weight, and distribution of ex- perimental points were studied by high-speed computer experiments.

On this basis it was determined how to adjust these various factors

to minimize the standard error for a given experimental precision.

For the particular case of gas PVT data, a density expansion is possible and approximate theoretical knowledge of the first five coeffi- cients is available. This allowed for the formulation of experimental

conditions (other than improved precision) leading to a decreased

standard error in one or more of the first four coefficients. Critical Phenomena in Binary Liquid Mixtures—To study critical phenomena in binary liquid mixtures the system 3-methylpentanenitroethane was selected. The refractive indexes of the liquid components of this system are such as to minimize multiple scattering in

studying critical opalescence. Experiments were carried out to determine the intensity of scattered light, the curve of coexisting concentrations and the behavior of the surface tension as a function of

temperature.

Scaling-Law Analysis—A systematic review of the experimental

evidence for the validity of the scaling hypothesis has been completed

asing the available data in the critical region for a number of systems.

An extension of the previous work on fluids, and a careful analysis of

several ferromagnets, have shown the scaling ideas to be consistent.

A closed-form equation of state based upon the scaling laws has been

suggested to relate the appropriate thermodynamic quantities (for

fluids—chemical potential, density, and temperature, for ferromagnets—internal magnetic field, net magnetization and temperature).

Agreement between the proposed form and the experimental data

shows that the equation of state is satisfactory within the entire critical region.

Light Scattering—The frequency spectrum of light scattered by

temperature, pressure and concentration fluctuations in a binary liquid

mixture was obtained using the linearized hydrodynamic equations.

The theory indicates that light-scattering measurements provide an

attractive means of measuring binary diffusion coefficients, as no

gradients are imposed on the system.

Molecular Motion in Solids at Low Temperatures—Recent heatcapacity measurements on deuteromethane crystals have demonstrated

that rapid transitions are taking place between the equivalent or nearly equivalent orientations of the molecules at temperatures well

below 1 K. In addition, conversion between the different nuclear-spin

states of the molecule accompanies the reorientation process. Similar

behavior is well known in solid H2 and D2, but it has long been thought

that such processes were "frozen out" at such low temperatures in all other solids. The present results at 0.?> K show tliat this is not necessarily the case in simple molecular crystals.

51
High-Temferature Heat Capacity Standard—Over 20 years ago, N^BS proposed SYntlietic sapphire (pure polycrystalline a— AI2O3) as a higlil}" suitable heat-capacity standard for interoomparing calorimeters in different laboratories from below room temperature to near

its melting point (above 2300 K). The heat capacity measurements

subsequently made by NBS from 15 to 1173 K have been the standard

reference since that time. A new sample of this substance has recently

been prepared as a Standard Reference Material, and precise calori- metric measurements from 273 to above 2000 K were performed on

several specimens. The results, using apparatus of improved precision,

match the earlier values over the entire range of overlap, as well as joining the previous measurements below 273 K.

In addition to providing a new, carefully characterized sample, this recent work inferentially has revalidated the older samples still in use. Technology of Liquid Helium—A publication on the "Technology

of Liquid Helium'' was edited and partially written by members of the

NBS staff. This monograph brings together articles b}^ 16 noted

authorities in cryogenic technology. Individual chapters cover a full spectrum of subjects including Resources, Production and Conservation, Properties, Techniques for Liquefaction and Refrigeration, Stor- age and Handling, Safety, Cryoelectronics, and Applications for

cryopumping, superconductivity, bubble chambers, and missile and

space systems.

Thermal Conductivity of Gaseous and Liquid Hydrogen—The

thermal conductivit}^ of normal and parahydrogen has been measured

at temjDeratures from 17 to 200 K and at pressures to 150 atm (15MN/

m^). These measurements have filled a large gap in the knowledge of

this property; they are the first comprehensive measurements on the

compressed gas and liquid at temperatures below 78 K. The behavior of

the thermal conductivity of hydrogen appears to be similar to that

of other fluids except that the temperature dependence of the con- ductivity of the liquid at constant density is much larger than that

of most other fluids except helium. These measurements complete a ten-year, XASA-supported program on the physical j^roperties of

parahydrogen at low temperatures.

Helium Heat Transfer—A 3-year program has been initiated to supply needed information on helium heat transfer. The technology of

superconducting materials and cryogenically cooled high purity sub- stances has reached a point where their use as electrical-current con- ductors is being planned into practical systems. But lack of reliable

information on helium heat transfer is a serious obstacle to the development of industrial devices. This new XBS program is funded by the

Atomic Energy Commission and monitored by a committee with representatives from all of the major AEC laboratories, XASA, DOD,

and NBS. It will include the generation of property values for con- 52
ductivity and viscosity of Helium I. Additionally, studies will be car- ried out analytically and experimentally to determine the heat-transfer

coefficients for supercritical Helium I and the heat transport through

Helium II as well as the interface between Helium II and solid materials (Kapitza conductance)

.

Thermodynamic Properties of Argon—The thermodynamic properties of argon have been calculated from an equation of state which was fitted to experimental P-p-T data from the world literature. These

calculations are one result of a study which was conducted over a period of several years and included exhaustive analysis of existing

experimental data by both statistical and thermodynamic theory. The

He^'-He* dilution refrigerator produces temperatures below 0.1 K. Refrigeration

is produced in a chamber inside a coil (arrow) used to measure the temperature. Suspended from the chamber are two devices to be tested—a Josephsonjunotion thermometer on the disc and a heat exchanger to the left. In use

the refrigerator is surrounded by a vacuum space and several thermal shields.53
results of this effort are described in an NBS publication containing

tabular values of density, internal energy, enthalpy, and entropy.

Diagrams of the specific heats, compressibility factor, and thermodynamic properties are included.

Saturated Liquid Densities of Oxygen^ Nitrogen^ Argon, and Parahydrogen—^^Standarized density data were prepared for the saturated

liquids of four commercially important gases—oxygen, nitrogen, ar- gon, and parahyidrogen. Users such as the Compressed Gas Association, the Department of the Air Force, and NASA require consistent

and accurate values for the physical properties of these gases in order

to achieve consistency in cost determinations. The State of California

has used extracted tables in their code (law) for cryogenic measuring

devices. The Compressed Gas Association is reissuing their pamphlet

P-6 using these values as the data base. He^-He^ Dilution Refrigeration—A refrigerator operating on the

He^-He^ dilution principle has been designed and constructed utilizing

a previously prepared tabulation of the thermodynamic properties of

He^-He* solutions. This refrigerator has achieved a continuous temperature of 0.020 K and a lowest temperature of 0.013 K. It was re- cently installed in a shielded room to minimize electromagnetic effects on sensitive instrumentation. Plans call for the experimental evaluation of transport and thermodynamic properties of He^-He* solutions,

determination of the physical properties of solids, and investigation of

devices such as the Josephson junction thermometer.

MECHANICAL PROPERTIES

Classical Theory of Sound Propagation—An analysis of the equation customarily assumed to describe the propagation of acoustic waves in a fluid continuum considering viscosity, compressibility, and

heat conduction has been carried out, calculating the transient as well

as the steady-state response predicted by these equations. A bounded

solution requires that an inequality involving the bulk and shear

viscosity, the specific heats at constant volume and constant pressure, and the thermal conductivity be satisfied. This inequality appears to be obeyed for all fluids except the molten metals, including mercury,

and possibly helium II. This failure probably indicates that some of

the assumptions made in deriving the initial equation are inadequate

when thermal effects are more prominent than viscous effects. The

common assumption that the velocity of sound in an inviscid fluid varies continuously with increasing frequency from adiabatic to iso- thermal values was shown to be invalid except for one very special

case. Absolute Viscosity of Water—The rheology section completed an

extended program in which measurements of the viscosity of a liquid

54
using two independent absolute techniques were compared. Ordinarily,

measurements of viscosity yield only the viscosity of various

liquids and reference is H2O at 20 °C and 1 atmosphere. These can

quite easily be made to 0.1 percent, but absolute measurements on any

liquid to better than about 1.0 percent are difficult and are seldom

undertaken. Moreover, most previous measurements have utilized flow

through a capillary and involved certain end effects which may cause undetected systematic error. The NBS measurements involved two

quite different types of flow, one inside an oscillating sphere, the

second through a channel whose dimensions could be established

very accurately. The results of these two measurements differ by 0.4 percent. By chance they bracket the value of H2O previously accepted

as the most reliable. Hence, the results of this program do not change

previously accepted values for viscosity, but do for the first time

provide a basis for assigning an accuracy (of ±0.2 percent) to all such measurements.

APPLIED MATHEMATICS

The Institute for Basic Standards conducts a program in applied

mathematics and statistics to meet varied needs in the development of new measurement techniques and in the evaluation of the results of

measurement. The level of the mathematics involved makes it essential to conduct fundamental mathematics research on a fairly broad scale. Gomputer-GontroUed Scanning Microscope and Image Processor—

A system has been designed and constructed for biological imageprocessing using a scanning microscope and several remote time-sharing computers. The scanning microscope, which is under computer

control, measures the light flux passing through a specimen on the

stage of a microscope. This measurement is made to one part in 256

for each point in square array of 256 by 256 points which is superimposed on the image appearing in the microscope. At present, the

image thus quantized is recorded on magnetic tape for processing by

a remote computer.

The remote computers (a PDP-10 and an ANFSQ32) are used to analyze the structure of the biological objects recorded on the tape.

The morphological structure of such biological objects as nerve cells and blood cells is obtained by having the computer decompose the

image into its component parts and then attempt to reconstruct the

object according to known rules governing the prescribed shape of

the whole object. This type of articular analysis is done in the programming language "LISP." This language provides facilities for

the manipulation of partial orderings (tree structures) which represent the results of the image analysis.

Through the use of the interactive feature of the time-sharing

computers, it is possible for a biologist to develop reasonably elaborate

55
criteria for the recog-nition and analysis of the objects portrayed in the

microscope image because as he develops these criteria he can see their

consequences immediately and refine or correct them at once. Currently, biologists are using this system to develop criteria for the

analysis of the cytoarchitecture and morphology of central-nervoussystem tissue, and for the study of autoradiographs of white blood

cells as part of a study of cell kinetics. Numerical Analysis—A method for computing absolute error bounds in terms of various matrix norms for the output of any matrix

inversion program was refined and incorporated into an existing computer program. Error analysis for the stationary-phase method of

approximation was completed. An explicit expression for the error term w^as found for the general case. Useful applications were made

in the approximation by asymptotic expansions of Bessel and other

special functions of mathematical physics. The method of Chester,

Friedman, and Ursell for approximating definite integrals with

nearly coincident saddle-points was extended.

FORTRAN Version of OMNITAB—T\\^ Bureau's highly user- oriented, general -purpose computer program, OMNITAB, has been

rewritten in ASA FORTRAN in order to make it as nearly machine

-

independent as possible. The program is being used successfully by

scientists in numerous university, industrial, and government laboratories on at least five different makes of computers. OMNITAB is used easily, quickly, and effectively by nonprogrammers for the cal- culation of tables of functions, for solutions of nonlinear equations,

for curve fitting, and for statistical and numerical analysis of data.

The program reads data in free-field format and executes instructions

Vv^ritten in the form of simple English sentences. It is particularly

well-suited for exploratory non-routine data analysis.

Evaluation of Linear Least Squares Computer Programs—Two

linear least squares test problems, both fifth-degree polynomials, have

been run on more than twenty different computer programs in order

to assess their numerical accuracy. Among the i^rograms tested were

representatives from various widely used statistical packages. Some

of these were highly inaccurate in comparison to programs (such as NBS's ORTHO) that have been available for many years. A number

of programs yielded results (coefScients) that were completely erroneous, containing not even one correct significant digit. The tests were run on several different computers, in double as well as single precision. It was found that those programs using orthogonal Householder

transformations or Gram-Schmidt orthonormalization were mucli more accurate than those using elimination algorithms. Programs

using orthogonal polynomials (suitable only for polynomial fits) also proved to be superior to those using elimination algorithms.

Selected Papers on Statistical Concepts and Procedures—The Bu56
reau has published Volume I, Statistical Concepts and Procedures, of

the twelve-volume NBS Special Publication 300, Precision Measurement and Calibration. This 441-page volume collects, for easy reference, reprints of 40 selected articles on topics of special importance to metrologists. Each of six sections of the volume is preceded by a foreword pointing up the purpose for which the papers are included.

Section titles are: (1) The measurement process, precision, systematic

error, and accuracy ; (2) Design of experiments in calibration ; (3) In- terlaboratory test; (4) Functional relationships; (5) Statistical

treatment of measurement data; (6) Miscellaneous topics. A list of

references and an extensive subject index are provided.

Finding Shortest Paths—In analyses of transport or communications networks, it is frequently assumed that a traveller will select (or a

unit of traffic will be routed along) a path which is "shortest" with

respect to time, cost, or some other pertinent feature. Because a single

applied study may require solving a great many shortest-path problems, perhaps involving large networks, it is important to classify

and experiment with various solution methods so as to know which

techniques may be best suited to particular situations. Following

preparation of a computationally oriented survey giving flow-charts

and descriptions of over 20 variants, the Bureau conducted comparative tests of the more promising methods on a variety of real and

"generated" networks.

Scheduling Algorithms—Proper scheduling in a transportation

system increases the public service derivable from a given investment

in fleet and facilities. Workers on mathematical scheduling methods

have tended to ignore the important interactions between patronage

and schedules. The Burau has developed operational algorithms for

near-linear ("acyclic") networks which account for this interaction.

Though focused on intercity rail movement, the technique should be

valuable for other modes and for urban transport as well. In addition.

Bureau-supported work has yielded the first rigorous treatment of

jointly optimal scheduling for "express" and "local" service. TECHNICAL ASSISTANCE TO OTHERS

Advisory and Consulting Services

Location of Cargo-Consolidation Centers—The development of a system of inland consolidation centers for marine cargo has been

suggested as a means of improving the efficiency of U.S. international

trade activities. As part of a project conducted jointly with the Technical Analysis Division for the Federal Maritime Administration, the

Operations Research Section developed a mathematical model to assist in the location and spacing of such centers, and to estimate some of the

57
potential benefits. Tlie model was implemented in a computer pro-

^rram, and exercised in a number of scenarios employing available

empirical data. Precision Measurements for Majjping—NBS is assisting the U.S.A.

Topographic Command in improving the application of precise microdensitometry and photographic image-structure evaluation in the pro- duction of maps. Starting with aerial photographs, cartographers

employ several intermediate photographic and photomechanical stages

in the preparation of the plates used to print maps. The assistance program involves training, consulting, preparation of physical standards

of measurement, and assistance in perfecting measuring techniques.

The improved ability to measure and quantitatively specify the per- tinent image-structure characteristics of the materials at each stage

should improve quality and effect economies.

Apollo IX Cameras Calibrated—The cameras used to photograph

the moon on the Apollo IX mission were calibrated by NBS. Four

cameras, each utilizing a different spectral region, were mounted in the

main hatch window. Conventional black-and-white film, infrared film,

and false-color film were used. The cameras were tested with films

identical to those used on the flight. NBS measured the lens character-
istics including back focal lengths, effective focal lengths, calibrated

focal lengths for photogrammetric use, radial and tangential distortion, resolving-power throughout the field, T-stop settings, lens-transmittance factor, relative distribution of illumination, and lens-modulation transfer function. In addition, the shutter speed, shutter efficiency,

and the wedge angles of the spectral filters were measured. Measurements were made with and without filters in place and the lenses were

evaluated by photographic, photoelectric, and visual methods. The

cameras provided photographs for use in detailed mapping of the

surface of the moon.

Electroluminescent Foimation Lights—Studies regarding the feasibility of installing strip-type electroluminescent (EL) formation

lights on high-performance (mach 2) aircraft have been completed.

Tests indicate that the EL lamps possess vibrational characteristics

superior to those of their incandescent-lamp counterparts, while their

linear geometry conveys better aircraft orientation to formation

wingmen. These studies have resulted in the specification of EL-type

formation lights for new aircraft (F-14: and F-15) while preparations

are underway for retrofitting existing aircraft such as the F-4.

Field Tests of Fog Detectors—The distance one can see signal lights

is an important factor in the safety of operation and landing of air- craft and in the navigation of ships. As part of the photometry program sponsored by the Department of the Navy, Federal Aviation

Agency, Air Force, and Coast Guard, the Visual Landing Aids Laboratory of the Photometry Section, Heterology Division, has completed

field testing of several types of back-scatter fog detectors at Areata

Airport, Areata, California—reputedly the foggiest airport in the

United States. The tests included operational suitability, reliability,

and correlation of fog-density measurements (obtained by the fog detectors) with direct measurements of atmospheric transmittance.

Recommendations on Archival Microfilm—Following several years

of research on the causes and prevention of blemishes on microfilm,

the results of a large-scale inspection of government microfilms were

published, and final recommendations for the prevention of such

blemishes were presented to the National Microfilm Association and

the Archivist of the United States. Although there had been practically no loss of information, the potential threat to archival records was

considered serious. The blemishes studied take several forms but are most often reddish spots about 0.1 mm in diameter. The blemishes were caused by minute amounts of gases generated during long-term

degradation of the cardboard cartons in which the films were stored. Recommendations covered raw film, exposing and processing conditions, storage conditions, and inspection. For archival purposes, the

importance of specifying storage and handling conditions as well as the characteristics of the films was emphasized.

375-572—70 5 59
Physical Properties of Glass-Fiter-Reinforced Plastic Rods—

Studies were undertaken for the U.S. Coast Guard to develop and

evaluate test methods for obtaining mechanical and electrical property

data on giass-fiber-reinforced polymer rods. These rods are used for

insulator guy systems needed for communications and navigational

aids towers. The properties studied were tensile strength, creep

strength, fatigue resistance, effect of ultraviolet radiation, water

absorption, dielectric strength, and high-voltage flashover resistance.

From the results of these investigations, a prototype insulator guy was

specified which will be useful as a laboratory reference for evaluating

improvements or variations in future insulator guy systems for Loran

C towers and similar applications.

Hearing Aids Circular Revised—NBS Circular 534, "Hearing Aids"

(1953) has been completely revised and brought up to date. This publication is directed toward the consumer and discusses sound and

hearing, and the general properties, selection, and care of hearing

aids. It also lists the principal hearing centers in the U.S., at which

assistance to prospective users of hearing aids is available.

Radio Standards Information Center—A Radio Standards and

Measurement Information Center was established to assist the NBS

technical staff and provide scientists and engineers with information on the use of RF standards and calibrations provided by NBS. The

Center will also provide information on the development, use, and

evaluation of accurate measurement systems. Outputs include specialized bibliographies, survey articles, state-of-the-art reviews, and

assistance in answering technical questions to the electronics industry,

universities, private research agencies and standards laboratories, and

other Government agencies working in the electromagnetic frequency

range from 30 kHz through the millimeter wave region. Specific subjects include attenuation, power, noise, field strength, voltage, current,

impedance, dielectric constant, pulse quantities, horn gain, and antenna

patterns.

Radiation Protection Suit—An electromagnetic radiation protection

garment was evaluated for use at frequencies below 100 IVIHz. This

garment was designed to protect personnel who are exposed to highlevel electromagnetic fields. Measurement techniques were developed to evaluate the shielding effectiveness of the suit in the presence of both

high- and low-level fields. The low-level measurement results were

encouraging, but high-level tests, using specially developed probes

for measuring high-level E and H fields (approximately 100 mW/

cm-), showed that the suit suffered from arcing and other nonlinear

effects and hence was unsafe for human use. Biomedical Electronic Metrology—Work in biomedical electronic

metrology has been initiated on a program basis. An extensive study was made of measurement needs, which led to the identification of

60
appropriate tasks and level of effort. Current work includes design

of environmental test chambers for studying radiation effects upon

animals and development of methods for measuring and calibrating

radiation intensity from ultrasonic diagnostic and therapeutic instru- ments. Also, with the support of the HEW Bureau of Radiological

Health, development was initiated on a new near-zone energy-density

measurement device for determining the level of stray radiation from

microwave ovens. Apollo 11 Lunar Range Experiment—NBS has cooperated with

scientists from the University of Maryland, Goddard Space Flight

Center, Princeton University, Wesleyan University, and other institutions in preparing the optical retroreflector array that was carried to the moon on Apollo 11. The round-trip light travel time from the

earth to the reflectors and back will be measured using short laser

pulses. The accuracy of resulting distance measurements is expected

to be 15 cm or better. One application of the range data will be to deter- mine the lunar orbit, librations, and radius to much higher accuracy

than they are now known. Improved information will also be obtained on the wobble of the earth about its rotation axis, the rotation of the

earth, and the difference in longitude between widely separated observing stations. Such geophysical information should help in understanding the interaction between the core and the mantle of the earth,

and should provide a direct test of whether the large-scale crustal

movements predicted by recent theories of ocean-floor spreading and

continental drift are taking place at present.

The Cryogenic Data Center—The NBS Cryogenic Data Center has

a data bank of over 30,000 carefully indexed references to the properties of materials at low temperatures. During the past year the Center's

professional staff noted over 8,300 articles of interest to the field of

cryogenics in its review of an estimated 340,000 titles, abstracts, or

full copy of the published and report literature. The articles noted were

listed in the 52 issues of the "Current Awareness Service" that is now

sent to 585 paid subscribers. The "Current Awareness Service" completed its fifth year of publication in April 1969, and "Superconducting

Devices" (a quarterly survey prepared in cooperation with Stanford

Research Institute and the Office of Naval Research) completed its first year of publication. There are now 115 paid subscriptions. All pertinent

documents were entered into the automated information stora^re and

retrieval system which is now in machine-readable form and machine

searchable. A new method of segregating the references stored on magnetic tape was developed. It enabled the initiation of a Selective Dissemination of Information (SDI) program which identifies new

publications in a particular field of interest. Characteristics of Slush Hydrogen—In cooperation with NASA,

flow characteristics of liquid-solid mixtures of hydrogen (slush hydro61
A magnified view of slusli hydrogen being pumped through a 1-cm orifice. Slush hydrogen offers distinct advantages over liquid hydrogen as a rocket propellant.

gen) in transfer lines have been measured. Losses through a restric- tion were also determined with slush and found to be essentially the same as with liquid hydrogen. A system was constructed in which the

solid content of slush could be increased by drawing off liquid and re- taining solids with a screen. Using this technique, solid contents greater

than 50 percent were attained in a dewar of freshly-made slush, while

solid contents in excess of 60 percent can be realized by aging the

mixture. Evaluation of stirring devices was made in the system to determine criteria for mixing the high-solid-content slush to a homogeneous, fiowable mixture. Production of gelled slush hydrogen was also accomplished and an analytical expression was derived relating the

quantity of gellant required to gel slush hydrogen to the quantity

required to gel liquid hydrogen. Information on the characteristics

and behavior of slush hydrogen is being sought for studies of applications to future space missions, and for the design of ground handling

equipment.

Conferences and Symposia

Precision and Accuracy in Measurement and Calibration—A West

Coast location was selected for a 3-day seminar on statistical tech- niques that had been presented four times in Washington. The Bureau

reported experience in the development and use of statistical experi62
ment designs especially tailored to the needs of calibration laboratories

for making economical intercomparisons among sets of standards.

Presentations by NBS statisticians were complemented by reports

from Bureau calibration laboratories that are implementing the new

computer-aided methods for data analysis, preparation of calibration

reports, and surveillance of the measurement ("production") process. The seminar was held at the West Coast University in Orange, California, and was sponsored by the N"ational Conference of Standards

Laboratories. Participants were 3Y metrologists from industrial and

government laboratories.

Photometry Seminar—Thirty-five registrants from photometric lab- oratories of private industry and government agencies participated in a four-day seminar on photometry given by the Photometry Section

of the Metrology Division May 12 through 16, 1969. The seminar

included lectures given by staff members on photometric quantities and

terminology, photometry and the eye, photometric standards and

methods, and projection photometry. The lectures were supplemented

by laboratory visits and demonstrations and with individual conferences with staff members. A similar seminar was held earlier for 14

representatives of Navy standardizing laboratories.

Symfosium on Thermal Expansion of Solids—Jointly sponsored by

the Westinghouse Astronuclear Laboratory and NBS, this first symposium emphasized the complete spectrum of techniques used in measuring the thermal expansion property. The program consisted of 12

invited and 24: contributed papers, including a historical review of the

theory of thermal expansion, a description of recent measurements at low temperatures, a review of x-ray and neutron diffraction methods,

and a description of measurements at high temperatures with neutron

diffraction. More than 100 scientists attended the three-day symposium, September 18-20, 1968.

Lengthy Angle, and Geometry Measurement Seminar—Thirty-two

dimensional metrologists from industry and government standards

laboratories and from the George Washington University Graduate

School participated in a 5-day seminar. Lectures by N"BS staff, laboratory sessions, and discussion periods covered: gage blocks; optical

and mechanical measurement of length, angle, diameter, and flatness

;

gear metrology; and statistical programs for determination of the

accuracy of measurement.

Fundamentals for Gas-Laser Length Measurement Seminar—

Metrologists, physicists, and mechanical engineers from university, in- dustry and Government participated in a 2-day seminar. Forty-one

persons attended lectures by NBS staff covering fundamental interferometry, gas lasers, holography, NBS laser instrumentation, and

practical pointers on use of lasers. Symposium on LLigh Pressure—An international symposium on "Ac63
curate Characterization of the High Pressure Environment" was held

at the NBS October 14-18, 1968 and attended by 140 participants from

the United States and abroad. Thirty-eight papers were presented, and

four panel sessions were held covering current research at high pressures in static systems and in shock wave experiments. In panel sessions,

five fixed points below 100,000 bars were proposed, and values for these

points recommended. The equation of state of sodium chloride was

recommended as a standard for the x-ray determination of pressure. The measurement of temperature in high-pressure apparatus and the

measurements of phase transformations as a function of temperature

and pressure using static and dynamic techniques were presented.

Dynamic methods included studies of phase transformations ranging

from 20,000 bars up to several million bars. Eecent developments in

static high pressure were also presented.

Short Courses in Noise and Power Measurements—By special re- quest, two brief measurement courses were presented to specially

selected U.S. Air Force personnel. One 4-day course covering RF power

measurements was presented in February 1969, and a 5-day course covering both high-frequency and microwave measurements in noise was presented in April 1969. Both courses were designed to satisfy the

specific needs of the Air Force and included discussions of NBS

measurement tecliniques as well as anticipated Air Force measurement

problems.

Seminars on Frequency and Time Stability—One hundred and

twenty-two registrants from private industry and government agencies attended two seminars on Frequency and Time Stability given by

NBS on February 18-20 and June 3-6, 1969. Four foreign countries were represented. The seminars developed a language that allows clear characterization of the instabilities in frequency standards. Measurement methods were described for obtaining data on the stability of

precision signal sources such as cesium beams, hydrogen masers, rubidium gas cells, and quartz crystal oscillators. Flicker noise and

other commonly encountered noises were discussed.

NATIONAL STANDARD REFERENCE DATA SYSTEM

The production of scientific information has undergone explosive

growth during the past decade. Furthermore, the development of

sophisticated instruments has meant that a greater part of this information is in the form of quantitative numerical data. These numerical

data are essential to the advancement of scientific understanding, the

planning of new research, and the utilization of research results in

industry. However, the great mass of data now being produced has

led to a serious problem in locating the data needed for a particular

purpose and ensuring that it is the best available. The National Stand64
ard Reference Data System aims to solve this problem by collecting

data from the world scientific literature, subjecting it to critical evaluation by experts, and condensing it into an accessible and easily usable

form.

The National Standard Reference Data System (NSRDS) was es- tablished in 1963 under a directive from the Federal Council for Sci- ence and Teclinology and the President's Office of Science and

Technology. The primary functions of NSRDS are: (1) to sponsor

projects for the compilation and critical evaluation of numerical data

in technical areas where the need for such data is clear; (2) to coordi- nate data compilation activities throughout the Government; (3) to

establish standards of quality for products of the system; and (4) to develop techniques for handling and disseminating scientific data. The

scope of the program is currently limited to well-defined properties of

well-characterized physical systems. These boundaries are not perfectly

sharp ; however, the emphasis is on intrinsic properties which can be

measured in a reproducible way and which are clearly defined in terms

of universally accepted physical theory.

The core of NSRDS is made up of a group of data centers, each of

which is responsible for a clearly defined technical area. There are currently about 25 of these centers. Roughly half are located in the

technical divisions of the National Bureau of Standards, and the re- mainder are supported on a contract basis in universities. Government

laboratories and industrial laboratories in all parts of the country.

Each data center is responsible for the various phases of compilation

of data within its technical scope. These consist of (1) locating the

pertinent publications in the scientific literature; (2) indexing and

abstracting the publications; (3) extracting and compiling the numerical data; and (4) subjecting the data to a critical evaluation in

order to obtain a set of recommended values. The last phase is the most

critical one and requires the intellectual input from experts who are experienced in the particular field. Every effort is made to utilize the

services of outstanding research leaders for this critical evaluation

phase.

The tangible products of NSRDS consist of tables of critically

evaluated data, accompanied by a detailed discussion of (the criteria for

evaluation and a critique of the measurement techniques by which the raw data were obtained. Ideally, such a publication provides the best

set of numbers for a scientist or engineer to use. In addition, it points out gaps in our existing knowledge and deficiencies in the measure- ment techniques, and thus helps to stimulate and guide future re- search. This feedback mechanism, by which the level of measurement

and interpretation of scientific data can be upgraded, is regarded as one of the most important functions of NSRDS. It has, of course, always been one of the principal goals of the National Bureau of

Standards.

65
The activities of NSEDS were given a specific congressional mandate through legislation enacted by the 90th Congress in Jnly, 1968. The Standard Eeference Data Act (PL 90-396) contains the following pro^TLsions : (1) a declaration that it is the policy of the Congress

to make critically- evaluated reference data readily available to scientists, engineers, and the general public ; (2) a directive to the Secretary

of Commerce to provide or arrange for the collection, compilation,

critical evaluation, publication, and dissemination of standard ref- erence data; (3) a directive to the Secretary of Commerce to prescribe

standard criteria and procedures for the preparation and publication

of standard reference data, as may be necessary^; (4) authority for

the Secretar}^, or a person or agency designated by him, to sell standard

reference data and to allow the proceeds to be used by the Bureau;

and (5) authority for the Secretary to obtain copyright, on behalf of

the United States as author or proprietor, for standard reference data

prepared or made available mider the Act. This Act provides the

authority for more varied channels of distribution of standard ref- erence data. Plans are now being developed to utilize tliis authority.

Current Activities

The activities of XSEDS are classified under eight program areas

;

six of these represent teclinical areas in which data compilation projects are active ; the remaming two cover more general functions car- ried out in the Office of Standard Reference Data. A summary of

recent accomplishments and current activities in each program area

is given below.

Nuclear Data

An NAS-NEC advisory panel meeting on nuclear data was held

in November, 1968. The general conclusion of the meeting was that

OSED should work toward sharing the responsibility for financial

support in the area of nuclear data, which previously has been almost

entirely in the hands of the Atomic Energy Commission. The first step to implement this recommendation was taken in an agreement

between OSED and the AEC to provide joint support for the Berkeley

Particle Data Center, which for several years has been compilmg and

publisliing elementary particle data. Proposals for other j)rojects on

nuclear data are being studied, and it is hoped that some of these can

be funded during the next year. The Proceedmgs of the Xeutron Cross Section and Teclmology^

Conference were published in two volumes with D. T. Goldman, Editor,

as NBS Special Publication #209 (1968). The Progi^am Manager

also chaired a meeting of an ISO Working Group, in Maj-, which was

concerned witli additions to the International Nuclear Energy Glossary

of Terms.

66
Atomic and Molecular Data

This program has emphasized the production of reference data compilaJtions in categories designated as highly important to the technical

community by its advisory panels. Considerable emphasis during the

past year was given to the publication of infrared spectral data based on the criteria established by the Board of Managers of the Coblentz

Society. The first 1,000 research quality spectra have been issued and

plans ar^ underway for the preparation and issuance of the second

group of 1,000 spectra. The success of this project has encouraged the

initiation of similar activities in the fields of Nuclear Magnetic Resonance, Raman Spectroscopy, and Mass Spectrometry. An advisory

group meeting to examine criteria for the publication of microwave

spectra is also being planned. In addition to these activities, an ad hoc

advisory panel met on May 27, 1969, to provide guidance for the compilation of interatomic distances in gas-phase molecules.

The following reports have been published

:

1. "Theory of the Ionization of Atoms by Electron Impact," by

M. R. H. Rudge, reprinted from Reviews of Modern Physics,

Vol.40, No. 3, July 1968.

2. NSRDS-NBS-26, "Ionization Potentials, Appearance Potentials, and Heats of Formation of Gaseous Positive Ions," by J. L. Franklin and J. G. Dillard of Rice University, H. M. Rosenstock,

J. T. Terron, K. Draxl of NBS, and F. H. Field of Esso Research

and Engineering Company, 1969.

3. ORNI^AMPIC-11 and 12, "Bibliography of Atomic and Molecular Processes for January-December 1968," compiled by Atomic

and Molecular Processes Information Center, Oak Ridge National Laboratory, under the direction of Dr. C. F. Bamett, 1969.

4. NSRDS-NBS-23, "Partial Grotrian Diagrams of Astrophysical

Interest," by Dr. Charlotte E. Moore and Paul W. Merrill, 1968.

5. Special Publication 306-1, 2, and 3, "Bibliography on the Analyses of Optical Atomic Spectra, Sections 1, 2, and 3," by

Dr. Charlotte E. Moore.

6. NBS Monograph 70, Volumes III, IV, and V, "Microwave Spectral Tables," by Paul F. Wacker, Marian S. Cord, Donald G.

Burkhard, Jean D. Petersen, and Raymond F. Kukol, Matthew

S. Lojko and Rudolph H. Haas, 1968, 1969.

7. NBS Technical Note 474, "Critically Evaluated Transition

Probabilities for Ba i and ii," by B. M. Miles and W. L. Wiese,

1969.

Solid State Data

The activities in the solid state program are reflected largely through

the continuing efi'orts of the data centers established in this area. The

assembly of bibliograpliy and tlie preparation of compilations on 67
crystal data, alloy data, superconductor properties, and diffusion data

are in progress. Two of the contributing efforts are being carried out

in India. They are "Phase Transformation in Solids," under the direction of C. K E. Eao, and "Crystal Defects in Alakli Halides," under

the direction of S. C. Jain.

The following reports have been issued

:

1. NBS Technical Note 464, "The NBS Alloy Data Center: Function, Bibliographic System, Related Data Centers, and Reference

Books," by Gesina C. Carter with L. H. Bennett, J. R. Cuthill,

and D. J. Kahan, 1968.

2. NBS Technical Note 482, "Superconductive Materials and Some

of Their Properties," by B. W. Roberts, General Electric Research and Development Center, 1969.

Thermodynamic and Transport Properties

During the past year, projects initiated earlier were carried on under

Office of Standard Reference Data sponsorship in the following areas

:

Chemical Thermodynamic Data on Inorganic Compounds

Thermodynamic Data on Organic Compounds

Properties of Molten Salts

Thermodynamic Properties of Polar Gases: Ammonia

Low Temperature Specific Heats

Thermodynamic Properties of Liquid Metals and Liquid Oxides

Systems at High Pressure

Yapor-Liquid Equilibrium in Binary Mixtures of Non-Electrolytes

at Low Pressures Binary Metal and Metalloid Constitution Diagrams

Thermal Conductivity of Selected Materials, Including the Elements

Viscosity and Thermal Conductivity of Mixtures in the Gaseous and

Liquid States Transport Properties of Fluids

Two new projects were initiated on the evaluation of data near the

critical points of binary liquid mixtures and on the thermodynamic

properties of nitrogen. The first of these complements a program on

the liquid-vapor critical region being carried out under other sponsorship. Together the programs constitute a thoroughgoing evaluation

of the data in a region which is difficult experimentally but of great

theoretical and practical interest. The project on nitrogen, in addition

to its own intrinsic importance, is coordinated with an international

program under the auspices of the International Union of Pure and

Applied Chemistry.

Additional continuing projects under other sponsorship are also being carried out in the following fields

:

Properties of Electrolyte Solutions

Thermodynamic Proj^erties of Metals and Alloys

68
Thermodynamic Functions of Cryogenic Fluids

Thermal Conductivity of Metals and Alloys at Low Temperatures

The Annual Index of Worldwide Published Thermochemical

Studies continues to be published yearly under the auspices of the

International Union of Pure and Applied Chemistry, with substantial

support from the Office of Standard Eeference Data.

Several projects have resulted in major published reports during

the year. These reports are

:

Molten Salts, Vol. 1, Electrical Conductance, Density, and Viscosity

Data, G. Janz, F. W. Dampier, G. E. Lakshminarayanan, P. K.

Lorenz, and R. P. T. Tomkins, NSRDS-NBS-15, 1968

Theoretical Mean Activity Coefficients of Strong Electrolytes in

Aqueous Solutions from 0 to 100 °C, Walter J. Hamer, NSRDSNBS-24:, 1968.

Thermodynamic Properties of Argon From the Triple Point to 300

K at Pressures to 1000 Atmospheres, A. L. Gosman, R. D. McCarty, and J. G. Hust, NSRDS-NBS-27, 1969.

Selected Values of Chemical Thermodynamic Properties, Tables for

Elements 35 Through 53 in the Standard Order of Arrangement,

D. D. Wagman, W. H. Evans, V. B. Parker, I. Halow, S. M.

Bailey, and R. H. Schumm, NBS Technical Note 270-4, 1969.

Ionization Potentials, Appearance Potentials, and Heats of Formation of Gaseous Positive Ions, J. L. Franklin, J. G. Dillard, H. M.

Rosenstock, J. T. Herron, K. Draxl, and F. H. Field, NSRDSNBS-26, 1969.

The last named was sponsored under the program in Atomic and

Molecular Properties but is of importance in the area of Thermodynamic and Transport Properties as well. Reports have been received

in several other areas which should result in publications in the coming

year. Colloid and Surface Properties

There are six current projects in the field of colloid and surface properties. These cover the following fields

:

Surface Tensions of Molten Salts

Critical Micelle Concentrations of Aqueous Surfactant Systems

Surface Tensions of Substances Liquid in the Vicinity of Room

Temperature and Below

Light Scattering by Liquids

Electrical Properties of Interfaces

Physical Data Pertaining to Phase Transition Kinetics

A report on the surface tensions of molten salts is in press and two

others are in the final stages of preparation.

69
Chemical Kinetics

A meeting of the Chemical Kinetics Advisory Group under the

chairmanship of Dr. S. W. Benson was held on May 19, 1969. This

group affirmed the view that the principal aims of the program should

be directed toward compilations of chemical kinetic data and monographs for reactions in the gas phase. They also recommended the

preparation of bibliographies for the assistance of those authors carry- ing out critical evaluations on subjects such as solution kinetics. The

importance of varied approaches embracing data sheets, short reviews,

and complete critical evaluations was endorsed.

The program has been responsive to this advice. The two data

centers have prepared bibliographies for use by authors preparing

critical evaluations. Data sheets covering the radiation chemical

behavior of six compounds are in preparation. A compendium of rate constants embracing approximately 1,500 reactions has been compiled.

The establishment of new data centers is under consideration.

The following reports have been issued

:

1. NSKDS-NBS-20, "Gas Phase Reaction Kinetics of Neutral

Oxygen Species," by Harold S. Johnston, University of

California, 1968.

2. NBS Technical Note 484, "A Eeview of Rate Constants of

Selected Reactions of Interest in Re-Entry Flow Fields in the

Atmosphere," by M. H. Bortner, General Electric Company,

1969.

3. NBS Report 9884, "A Compendium of Evaluated and Estimated

Rate Coefficients," by David Garvin, 1968.

4. "The Biradical Mechanism in Small-Ring Compound Reactions,"

by H. E. O'Neal and S. W. Benson, reprinted from the Journal

of Physical Chemistry, 72, 1866 (1968).

Data Systems Design

The major ejfforts of the Data Systems Design Group have been

divided among two coequal activities

:

(a) design of and programming support for computer-assisted

typesetting and composition of data tables and associated tex- tual and bibliographic material, and

(b) development of a comprehensive package of general-purpose

programs for data file manipulation.

Work has been completed on a series of general-purpose computer

programs for automatic typesetting of computer-generated text and

tables. One of these (TYPSET) handles program listings and for- matted computer printout. Another called KWIND is specialized to typesetting KWIC (keyword in context) indexes. Both programs

have provisions for converting the normal upper-case computer out- put to a more readable format with upper- and lower-case characters,

and even Greek characters where appropriate.

70
In the area of data file manipulation a series of programs have been

written to reformat and edit data files in three categories

:

( a) fixed-field files of fixed-length records,

(b) free-field files of structured but variable-length records, and

(c) free-field unstructed files of variable-length records which have

been suitably flagged.

For files which satisfy the above characteristics the programs per- mit exceptionally easy file manipulation.

The programs have been documented in a series of Technical Notes

issued through the Superintendent of Documents.

A distribution system for general-purpose computer programs on

magnetic tape has been started as a pilot program for a larger effort on NSRDS data tapes. The machinery for distribution of magnetic

tapes via the Clearinghouse for Federal Scientific and Technical In- formation is proving quite successful, judging from the reception by

the technical press of the release of the first magnetic tape in the series. Information Services

Despite the limited financial resources of the Office of Standard

Reference Data, which have imposed severe restrictions on Information Services, this operation is continuing to progress and to make

effective contributions to the NSRDS program. Some of the contributions are

:

Data File—The Data File has established a very comprehensive

collection of worldwide compilations of data in the physical sciences. Its holdings of reference data compilations are as extensive as will be

found anywhere in the world. An annotated accession list of the holdings is in preparation.

Compilation and Editorial Services—This unit is responsible for

the monthly NSRDS News. This newsletter has a worldwide circulation of over 4000 subscribers. This unit also acts as the editorial intermediary between the Office of Standard Reference Data, associated

data centers and projects producing data compilations on the one hand

anid the government publication mechanism on the other. In the pres- ent reporting period, 20 publications have been produced and 17 are

in process. Inquiry Services—This unit provides coordinated replies to inquiries

received by the Office of Standard Reference Data from the Data

File, from the Compilation and Editorial unit of the Office, and from

other sources in the NBS and NSRDS associated centers. If the query

is within the capability and scope of the program, a reply is forwarded.

Sometimes inquiries are referred elsewhere or reference sources furnished, or data compilations or other publications are provided. In

the present reporting period, 558 inquiries were received, compared to 400 in the previous year. 71
Analysis and User Relations-—In order to develop an effective in- formation system to provide broad coverage of properties data in the

physical sciences with a flexibility capable of meeting the needs of a large variety of specialists, this unit has been examining the users, actual and potential, of standard reference data. Toward this end, it conducted two very preliminary studies. The first queried by mail 212

persons who received NSRDS publications as to the use and usefulness

of the publications received. Ninety-eight returns were received

(47%). Of these, 86 indicated they found the NSRDS publications

useful ; 4 indicated they did not find them useful ; one did not reply

to that question ; and 7 did not remember the publication.

The second effort was a pilot survey in the form of an interview/

questionnaire aimed at providing information on technical reference

data use patterns of NBS scientists. This pilot study revealed that 42, or 84 percent, of a representative sample of 50 NBS scientists use physical properties data. These scientists, on the average, spend approximately one hour of their working day in seeking or discussing their

data requirements. One of the results of this pilot study is a revised

interview/questionnaire suitable for survey of similar information

by other organizations.

72
INSTITUTE FOR MATERIALS RESEARCH

Emphasis in the Institute for Materials Research (IMR) is on measurement methodology for well-characterized materials.^ This emphasis supports the unique mission to develop standards of measure- ment for the commercial, industrial, and educational communities of

the Nation and to provide research and consulting services to other

Government agencies. About 25 percent of IMR's work is for other

Government agencies.

Work falls into the following broad areas

:

1. Preparation and characterization of materials

2. Standard Reference Materials

3. Data on the properties of materials

4. Technical assistance to others. PREPARATION AND CHARACTERIZATION

OF MATERIALS

This area includes such activities as the synthesis of new materials,

purification of materials, crystal growth, and the analysis of materials

with respect to chemical composition and structure. Outputs of these

activities are sample materials to be used for specific research purposes,

and the development of new techniques and procedures for preparing

or characterizing materials.

Preparation

Synthesis

Synthesis of Organohoron Compounds—A number of new or- ganoboron compounds have been synthesized for the first time. Two

of these, ethynyldichloro- and ethynyldifluoroborane, are the first re- ported members of the hitherto unknown family of organoboron

halides of the acetylenic series. The syntheses were carried out using

both photochemical and conventional synthetic teclmiques. The com- pounds appear to be significantly more stable than most boronsubstituted acetylenes. Since they are thus amena})le to detailed physical investigation, they are of considerable interest for detailed studies

of structure and bonding in teclmologically important organoboron

73
derivatives. Preliminary microwave spectroscopic studies have been

carried out in cooperation with members of the Institute for Basic

Standards. Some novel organo-substituted compounds containing

boron-boron bonds have also been prepared and are of particular

interest as new derivatives containing preformed aggregates of boron

atoms. The new compounds are being investigated both from the

viewpoint of their fundamental chemistry and as possible precursors

to useful boron-containing materials such as the borides.

Organometallic Complexes of Biological Interest—Interactions between transition metal ions in binuclear complexes have been observed

in a large number of compounds. Kesearch in this area has been ex- tended, in a cooperative study with chemists at the State University of

New York at Plattsburgh, to include complexes of biologically significant ligands such as the purine bases. Dimeric adenine complexes

of copper (II) have been synthesized in both neutral and anionic forms,

and the magnetic behavior of such complexes has been studied by

electron paramagnetic resonance spectroscopy. These compounds are the first reported examples of purine-base complexes with unusual

magnetic properties attributable to exchange-coupled metal-ion pairs.

The complexes are of interest as model compounds for a number of

biological systems, particularly in view of recent suggestions that the occurrence of metal ion pairs may be significant in biological processes involving enzymes and proteins with trace metal ions. Reactive Intermediates in Chemical Synthesis—In the past several

years increasing recognition of the importance of synthetic chemical

processes derived from highly energetic conditions has resulted in an

array of novel and useful chemical structures. To a large extent these

advances have derived from the development of the characterization

and descriptive chemistry of reactive intermediates—small molecules

or molecular fragments produced thermally, by photo excitation, or in

plasmas or flames—which determine the chemical pathways available

outside the energy zone. In previous studies, complex product mixtures resulting from inter- actions of low-density fluoride plasmas with ceramic or organic poly- mer materials were rationalized in terms of a few key reactive

intermediates. Such an approach has been extended to examination of

materials such as organometallics and their halides upon subjection

to comparatively lower energy irradiation with visible and ultraviolet

light. Primary and secondary reactions which occur at rates sufficiently

different to permit identification by electron spin resonance (ESR) or mass spectrometry have been demonstrated. Solid solutions of methyltrichlorosilane and trichlorosilane show non-additive behavior at liquid

nitrogen temperatures, where the methyl free radicals associated with

photo-cleavage of methyltrichlorosilane by itself disappear in the pres- ence of trichlorosilane to form a new, complex radical product. The

74
potential of such "reagent" intermediates for specific free radical

syntheses is further illustrated by the photolysis of phosphorus tri- chloride at liquid nitrogen temperatures. The primary photo-cleavage

reaction produces a novel radical, PCI2, along with mobile, reactive

chlorine atoms. The latter produce secondary reactions with unreacted

PCI3 molecules to generate still another new radical, PCI4. Dilution

experiments with the inert gas Xe indicate the secondary process can

be inhibited in the solid PCI3 matrix.

^^1^-Labeled Amino Sugars—Naturally occurring sugars that possess

a chemical structure in which one or more oxygen atoms is replaced

by a nitrogen atom are often found as components of substances, such

as antibiotics, which have important biological functions. IMR scientists have now synthesized the first amino sugars having a ^^N-content

greater than 99 percent to study the nuclear magnetic properties of

the isotope-labeled compounds and the potential of magnetic res- onance parameters for structural analysis.

Periodic Acid^aNovel Oxidant for Organic Compounds—Controlled

oxidation of organic compounds is an important step in the synthesis

of pharmaceuticals and other substances of biomedical significance.

Periodic acid, a reagent well known for its ability to cleave 1,2-diols,

has now been found also to be a useful oxidant of polycyclic, aromatic

hydrocarbons. A unique, two-fold character of response to periodic acid

by such hydrocarbons has been observed : production of ( 1 ) couplingreaction products through a radical intermediate, or (2) quinones by a two-equivalent oxidation mechanism that does not involve a radical

intermediate. A most interesting example is the oxidation of the hydrocarbon azulene with periodic acid, which gives a polymerical product

that is highly paramagnetic and retains this free-radical property for some time at 485 °C.

Crystallization and Morphology of 66-Nylon—Current investigations are primarily aimed at determining the nature of the crystallization habit exhibited by 66-nylon when it is crystallized from dilute as well as concentrated solutions of the polymer in glycerol. The objective

of this study is, among other things, the elucidation of the manner in

which the chain molecules of this polyamide fold during crystallization.

The polymer has been observed to crystallize in a variety of forms depending on the condition of crystallization. Among the habits observed on crystallizing from dilute solutions are simple parallelepiped lamellae as well as multi-layered lamellae crystals whose constituent chainfolded layers are apparently twisted. Concentrated solutions have been

observed to yield on cooling complex petal-shaped aggregates as well

as negatively birefringement spherulites. The reUitionship between

these and other forms of crystallization exhibited by 66-nylon is beingstudied.

375-572—70 6 75
66-Nylon is being studied to determine the manner in which the chain molecules

fold during crystallization. Shown here is a scanning electron micrograph of (X520) spherulites and other aggregates (top left) of 66-Nylon grown from a concentrated solution of the polymer in glycerol.

Polymerization at High Pressure—High pressures (10-20 kbars)

have been utilized to produce new fluorinated copolymers of

tetrafluoroethylene with the olefins 3,3,3-trifluoropropene ; 3,3,3,2-

tetrafluoropropene ; 2-trifiuoromethyl-3,3,3-trifluoropropene ; and

3,3,4,4,5,5,5-heptafluoropentene-l. At autogeneous pressures only

liquids and oils are produced, instead of the strong high molecular

weight copolymers produced at high pressures. The comonomers all have some retardation effect on the polymerization of tetrafluoro- ethylene. The objective of the research which is sponsored by AQDP is the expansion of our basic comprehension of the molecular and struc- tural factors that determine the mechanisms of polymerization, the

nature of the transition state, and the molecular size. The composition of the copolymers produced at various pressures from 3,3,4,4,5,5, 5-heptafluoropentene and tetrafluoroethylene is a function of the composition of the monomer charged. The pressure

does not affect the composition appreciably, although it drastically

enhances the molecular size. Reactivity ratios found for these sys- tems work against incorporation of the tetrafluoroethjdene in the

76
copolymer. The rate of these copolymerizations becomes much more

rapid at high (10:1) ratios of tetrafluoroethylene to the other monomer.

Separation of Polymer Molecules hy Floio—The basic idea behind

separation by flow is easily explained. An isolated polymer molecule

flowing through a thin capillary and undergoing Brownian motion

will have an average velocity greater than that of the solvent. This

is because the center of the particle (assumed to be a rigid sphere)

cannot get any closer to the walls of the capillary than its radius. It therefore samples only those solvent velocities away from the walls;

since the solvent velocity is larger, the farther the distance from

the wall, larger molecules will have larger average velocities than

smaller molecules. This "Separation by Flow" mechanism has been

advanced as the fundamental basis for the phenomenon of Gel Permeation Chromatography. The quantitative understanding of this

basic phenomenon thus now allows the systematic design of instruments to separate molecules or particles of different size. Chelating Agents as Potential Adhesives for Dental Restorations—

One of the unsolved problems in restorative dentistry is the lack of

adhesion between tooth tissues and permanent restorations under

conditions existing in the oral cavity. Micro-leakage between cavity

and restoration can result in secondary caries. In the present work,

supported by the Dental Division of the United States Army Medical

Research and Development Command, potential adhesive liners that

may bond to tooth structure and plastic restorative materials have

been studied. These tailor-made molecules were selected on the basis

of theoretical considerations taking into account the chemical composition of the tooth surface and the compatibility of these com- pounds with cold curing acrylic restoratives. The newly synthesized

compounds contained groups that react with calcium to form chelates and other groups that could copolymerize with dental resins. Dentinal and enamel bovine tooth surfaces were treated with these

compounds and the adhesion to a cold curing acrylic resin was then

determined. The teeth were stored up to 30 days at 37 °C in solutions

of different acidities. The tensile strength of the bond between tooth,

liner, and restorative material was taken as a measure of the bonding

efficiency of a compound. Treatment of the dentinal and enamel

surfaces with most chelating agents produced only insignificant in- creases in bond strength or gave results that were not always reproducible. However, applications of dilute aqueous solutions of many

heavy metal salts changed the surface of tlie enamel within a few

seconds so that the restorative resin adhered even without the use

of an intermediate liner after storage in water for 24 hours. This

behavior can be explained by the formation of secondary covalent

bonds, causing weakening of tlie bond of the resin's ester group on 77
prolonged exposure to water. The results with shnilarly treated dentin

surface showed less adhesion, but were promising enough to justify

continuation of this line of mvestigation. It is hoped that the use of

potential adhesives in combination with treatment of the surfaces

with metal salt will lead to improved bonding at the tooth surfaceacrylic interphase.

Electrodeless Electrolysis—Both solid materials and fused salts have been electrolyzed without being in contact with any solid conductor. The current was carried to the materials via glow discharge

in a gas at a pressure of about 0.1 torr. Under these conditions some

ceramics became electrically conducting, and dendrites of nickel,

cobalt, copiDer, silver, tin, and magnesium were dep)osited from fused

salts. The experiments show that metallic electrodes are not essential

for electrolysis to occur. Vaj)or Growth of ALOs Bicrystals—EViE has, with the suj)port of

the Advanced Research Projects Agency, developed a teclmique to grow aluminum oxide mono- and bicrystals by a vai^or transport process. Monocrystals are being grown b}^ this method with the goal of

higher purity in order to imj)rove the measurements of many j^hysical

and chemical properties. Bicrystals are being grown in order to measure properties of the interface.

Basically, the process consists of reacting AICI3 with oxygen under

carefully controlled conditions of pressure and temperature with the

resultant deposition of AI2O3 in single crystal form in a seed. By the

use of double seed crystals, bicrystals contaming symmetrical tilt bomidaries have been grown in sizes suitable for research specimens.

The purity of the crystals is quite high, of the order of 40 ppni by

weight, or less, total cation impurities.

Morphology of Ice Cylinders—Recent experimental and theoretical

results have shown that the initial morphology of growing crystals can

be ]3redicted. Experiments on the growth of single-crystal ice cylinders

in slightly supercooled water have been carried out. The initially

Experiment has confirmed theoretical predictions of the initial morphology of groNving crystals. Shown here are pertubations on the surface of ice cylinders

at supercooled temperatures —0.20, —0.09, and —0.08 °C, left to right.

78
smooth cylinder develops approximately sinusoidal perturbations

parallel to the axis of the cylinder. The wavelengths, A, of these

perturbations have been measured as a function of the bath undercooling, aJ". Based on a morphological stability analysis, theory predicts that of all possible wavelengths, the wavelength of maximum

amplification will appear on the growing cylinder. Excellent agree- ment has been obtained between the theoretical prediction and the

experimental results. The sinusoidal perturbations are the precursors

of dendritic growth. Thus, the initial stages of the development of

dendrites can be successfully treated by morphological stability theoiy

.

Melt Groioth of Cuprous Oxide Crystals—As a part of a crystal

growth project sponsored by the U.S. Atomic Energy Commission,

large single crystals of CusO have been grown by a float zone process in

controlled oxygen pressures. Typically, crystals of 1.5 cm diameter

and up to several centimeters long have been grown, with total cation

impurities of less than 40 ppm.

New Teclinique for Target Current Scamning in Electron-Prohe

Microanalysis—In the electron-probe microanalyzer, a beam of elec- trons focused on the surface of a specimen produces x rays, secondary

electrons, and a current from specimen to ground, known as target

current. The target current signal, which is affected by the back scat- tering of electrons, varies both with composition and topographic

variations of the specimen surface.

In IMR laboratories, a concept has been developed for handling

the target current signal in a way that permits separating and emphasizing the topographic aspects of a specimen independent of composition. This may render unnecessary in many cases the installation of

secondary electron detectors and associated electronics. An amplifier

Target current scans of titanium boride contaminated with iron. The iron shows

as the bright phase in the upper image. Upper image : linear target current, showing atomic number differences. Middle image : derivative image, showing

topography. Lower image : combination of both signals.

79
lias been constructed in which the target current signal and its first derivative are amplified and recombined in any desirable proportion.

Application of this concept in the examination of a titanium boride

specimen makes evident both the surface topography and the distribution of iron impurity.

Multi-Element Trace Analysis ty Isotope-Dilution Sparh-Source

Mass Spectrometry—Highly sensitive methods have been developed

for trace analysis of high-purity materials using the spark source mass spectrometer with isotope dilution techniques. In a typical analysis, for example, the determination of trace elements in zinc, a solu- tion of the zinc is spiked with isotopically enriched solutions of the

elements to be determined, the elements are electroplated onto highpurity gold wires, and the wires are sparked in the mass spectrometer.

By measuring the mass spectra and applying appropriate calculations, the concentrations of the trace elements in the original zinc

sample are determined.

The method permits the simultaneous determination of groups of

six or more elements and provides determinations at concentrations

of parts per billion, e.g., 20 ppb tin in zinc. The method was developed

especially to provide analyses of NBS standard reference materials

and has been applied to analyses of zinc, platinum, and gold. Further

work indicates general applicability to the analysis of other materials

such as steel and glass.

Cell for electroplating impurity elements from isotopically modified solutions onto gold electrodes prior to mass spectrometric trace analysis.

80
Improved Trace-Element Analysis—A new approach lias been developed that offers at least a hundred-fold improvement in the

selectivity and sensitivity of many existing spectrophotometric and

spectrofiuorometric procedures. It uniquely combines the inherent

selectivity of solvent extraction and the statistical advantages afforded

through utilization of three-component complexes. Improved sensi- tivity is obtained by performing exchange reactions on ion-pairs di- rectly in the organic extract. In the proposed method conditions are readily obtained whereby a weakly chromogenic or fluorogenic cation

is replaced instantaneously by a highly colored or fluorescent dye.

Unreacted dye is readily extracted into water, leaving only the dye

complex in the organic phase.

Recent studies involving nanogram amounts of gold and uranium

have clearly demonstrated the improved selectivity and sensitivity of

the extraction-exchange method. At least one other advantage is also apparent. The method shows promise of being a simple way of obtaining many new and potentially useful complexes which, heretofore, were impossible to prepare by conventional techniques.

Multi-Element Analysis hy Molecular Absorption Spectrophotometry—In the metals industry great emphasis has always been placed on the speed of analysis, with accuracy being of somewhat secondary

importance. The increasingly stringent demands of modern day technology, however, are creating new needs for more accurate as well as more rapid methods of analysis.

Absorption spectrophotometry, while always regarded as a highly

accurate technique, has until now been limited almost exclusively to single-element analysis. Recent studies, however, have shown that

the careful selection of chromogenic reagent in combination with computer evaluation of data can yield systems and procedures that are equally accurate for the determination of as many as five or six ele- ments simultaneously. The primary prerequisites, in order of their

importance, are degree of spectral overlap, reproducible formation,

and stability of the metallo-organic complexes. These parameters

have been investigated and closely evaluated in the recent development of a multi-element spectrophotometric procedure for the simultaneous determination of cobalt, nickel, and copper. Accuracy is about

1 percent at the part-per-million level and less than ten minutes are required for both analysis and computation.

Interferometer Control for Mosshauer Spectrometer—A Mossbauer

spectrometer uses some type of device for producing a Doppler motion

that provides the necessary gamma-ray energy shift. Electromechanical transducers are often used, but it is important tliat the motion be

measured accurately. An electromechanical system has been modified

for control by an interferometer. The device, which uses a laser light

source, compares an interference fringe count with standard fre- 81
To provide tlie accurate constant acceleration needed for use with a Mossbauer

spectrometer, this device compares an interference fringe count v^ith a standard

frequency, differences being used as feedback to control the motion. Constant

acceleration is achieved by incrementing the standard frequency with time. quency. Any difference is detected, and a correction signal is generated

as feedback to the electronic system. Constant acceleration is acliieved

by incrementing the standard frequency linearly with time. This ar- rangement provides the extreme accuracy and precision of motion

which enables the Mossbauer spectrometer to produce spectra of unIDrecedented reliability.

New Clean-Room Facility—A clean-room facility of advanced type

has been designed and installed and is providing improved handling

capability in ultratrace analysis. The facility consists of two clean rooms separated by a perforated wall partition, together with rooms

to prepare personnel for entry into the clean areas. Horizontal laminar

air flow, at an average rate of 100 lineal feet per minute, is provided

for the clean areas. An absolute filter bank removes essentially all air- borne particles greater than 0.5 />im in diameter. Each cubic foot of air

in the room adjacent to the filter bank contains less than 100 such particles, while a particle-level less than 1,000 is maintained in the second room. The rooms are currently used for microscopic examinations and

for the assembly and disassembly of apparatus when extreme cleanli- ness is a requisite. Two laminar-flow fmne hoods permit mild chemical

reactions to be performed under ultra-clean conditions.

82
ImfToved Trace-Chromium Determination—A method of improved

sensitivity and accuracy has been developed for determination of as

little as one ten-billionth of a gram of chromium. The coulometric

method consists of titration of chromium with electro -generated fer- rous ion in a specially designed electrolysis cell of small volume to permit increased sensitivity. An improved end-point detection technique was lalso devised to facilitate the analysis. The new method

provides sensitivity and accuracy of at least an order of magnitude

better than previously available in the low concentration range. Microgram quantities of chromium can now be determined with an accuracy

better than one part in a thousand while nanogram amounts can be

determined to within a few percent of the amount present. From that

point the accuracy drops off rapidly down to a lower limit of about

a tenth of a nanogram (one ten-billionth of a gram). The method

should be widely applicable to trace chromium determinations ranging

from biological and clinical materials to metallurgical products. At

NBS, it has been used for determination of chromium in ruby laser using only milligram amounts of the crystal in the determination.

Polarographic Analysis of Air Pollutants—Polarographic methods

have been developed for the simultaneous determination of very low

levels of iron, copper, cadmium, and lead present as air pollutants.

Samples are collected on conventional filters which are ashed or from

which the contaminant may be extracted by leaching in favorable

cases. An ammonium oxalate supporting electrolyte is used, and the

metal is determined by fast scan polarography. For extremely low

levels of contaminants, preelectrolysis into a hanging drop electrode

followed by anodic stripping voltammetry is used. The submicrogram

detection limits make possible a number of application areas. The

methods have been applied to a wide range of air-pollution problems

including determination of the metallic contaminants of suburban

and semirural residential areas, and to collaborative studies with the

National Air Pollution Control Administration. They have also been

applied to monitoring ambient lead in a laboratory involved in glassmaking operations, and even to the determination of metallic constituents in relatively clean laboratory air to identify sources of blanks

in trace analysis.

Analysis of Thin Metallic Films—Polarographic methods have been

developed in IMR laboratories which have become extremely important for the microchemical analysis of thin metallic films such as are used in electronic circuitry. Such films must be accurately analyzed, yet there is not sufficient material to be accurately weighed, let alone enough for analysis by conventional methods. The polarographic

method consists in dissolving the film and quantitatively determining

each constituent by electroanalytica;! measurement with a dropping

mercury electrode. Methods applicable to films composed of anti83
mony-bismutli, copper-nickel-chromium-aluminum, nickel-chromium,

lead-selenium, and lead-tin-tellurium, respectively, have been developed to date, with total film amounting to only a few tenths of a milli- gram in each case. Ion-Selective Electrodes for Microanalysis—Ion-selective electrodes are becoming increasingly useful in chemical analysis, but the physical

dimensions of these sensors have limited their applicability to situations in which relatively large amounts of sample are available. IMR

research on miniaturization of these sensors has resulted in two important developments. A commercial silver sulfide ion-selective elec- trode has been modified for use with small samples by drilling 5- to

10-/xl depressions directly into the polycrystalline silver-sulfide membrane of the inverted electrode. Such an arrangement permits measure- ments on 5 jtxl of sample down to the lowest detection limits possible

with this electrode. The first successful truly miniature ion-selective electrode has re- sulted from redesign of the solid-state fluoride electrode. The construction resembles the conventional electrode except that the lanthanum

fluoride membrane consists of a small conical-shaped crystal sealed

in a plastic tube drawn down to a fine point. The sample volume re- quirement is less than 2 fxl (1/25 of a drop) and the needle-like profile of the electrode makes it adaptable to in situ, in vivo, and on-line

continuous analysis. Further miniaturization in this manner is feasible

and should provide electrodes of even greater versatility.

Aqueous Boric Acid-Borate-Mannitol Equilibria—Despite widespread use and extensive research on polyalcohols, especially mannitol,

as addition agents in boric acid titrimetry, the stoichiometry and

equilibria involved have not been clearly established. In view of the

importance of this procedure in the determination of boron, IME,

chemists have reinvestigated this system. Proton nuclear magnetic

resonance spectra of boric-acid-borate-mannitol solutions in deuterium

oxide and electrometic pH measurements of aqueous solutions were

consistent with the formation of both 1 : 1 and 1 : 2 borate-mannitol

complexes. The successive formation constants of the complexes were

found to be only slightly different {pK= -2.79; pK^= -2.19). Fail- ure to recognize this fact has led previous investigators to misintrepret

data and to erroneous conclusions. Reevaluation in light of the present

results brings several earlier discordant findings into agreement with

the IMK conclusions and establishes a consistent model for this important analytical system.

Boron isotope ctnalyses—A surface emission mass spectrometric

technique for the precise measurement of boron isotope ratios has been

developed. A single-filament tantalum ribbon source was used, and

^^B/^°B ratios were determined by measuring the relative abundances

of Na2^^B02'^ and Naa^^BOa^ ions, at masses 88 and 89, respectively.

84
The effects of various parameters such as sample-mounting procedure,

filament material, sample size, total sample composition, and sodium

concentration were studied and alternative procedures were evaluated.

This precise technique was used to measure the absolute isotopic

abundance ratios of two boron isotopic standards; SRM 951,

iiB/ioB=4.0362±0.0013T; and SKM 952, ^^B/"B=0.053199±

0.000032. These standards and the new mass spectrometric measure- ment technique will be of significant value for the precise characterization of the boron used in nuclear reactors. They should also be useful

for the characterization of isotopic variations in natural boron.

Atomic Weight of Ruhidium—The atomic w^eight of rubidiimi has

been redetermined by solid-sample thermal emission mass spectrometry. The absolute isotopic ratio was obtained by calibrating the

instruments used with samples of known ^^Kb/^^Eb ratio, prepared

from solutions of the separated isotopes. The resulting atomic weight

of 85.46776 ±0.00026 is not significantly different from the old value of

85.47 but shows a significant increase in precision.

Solvent ExtractionWithHydrogen Bis {2-Ethylliexyl) Phosphate—

Solvent extraction is one of the most useful techniques for separating one constituent of a mixture from interfering substances prior to

analysis. Alkyl esters of phosphoric acid have been shown to be excel- lent extractants for metallic elements. One of these esters, that of 2- ethylhexanol, has been used extensively for rare-earth separations. A

comprehensive study of the extraction of all the metallic elements into

this reagent as a function of mineral-acid concentration has been completed. As a direct result of these studies, three new applications for

this reagent in radiochemical separations have already been developed,

and several other separations schemes, both for individual elements

and for groups of elements, are under investigation. The separations

are rapid, quantitative, and, with suitable choices of the back extractant, the mineral acid, and the concentrations, substantially interfer- ence-free. Nondestructive Determination of Impurities in Ruby Laser Crystals—The effect of trace elements on the performance of solid-state

lasers is as yet incompletely understood. In order to make possible a

later correlation of laser optical properties Avith trace-element content,

nondestructive neutron activation analysis methods have been applied

to determination of over 10 trace elements in ruby at the ppm and ppb

levels, with precisions of 2 to 5 percent. The samples were irradiated

in the NBS reactor and the trace elements determined by gamma

spectroscopy using a lithium-drifted germanium gamma-ray detector

of large volume and liigh resolution. Because of the liighly refractory

nature of the matrix, other trace-analysis techniques proved to be of

limited applicability. These new procedures provide a definitive characterization of ruby crystals and pa\'e the way to an elucidation of the

relationship between composition and optical behavior.

85
Neio Applications of the Gockcroft-'Wdlton Neutron Generator—

A comprehensive study of the utility of 3-MeV neutrons, from the

(^H9'H,n)3He reactions, for compositional analysis of macro constituents, has been made. This expands considerably the analytical

application of the small neutron generator, previously limited to 14:-MeV neutron activation analysis. The study included experimental

determination of the analytical sensitivity for more than 70 elements

along with the gamma-ray spectra from these elements. In addition

to their direct analytical application, these results may be used for

the prediction of interferences from the buildup of the 3-MeV neutron

flux encountered in 14-MeV neutron activation analysis from deuterium embedded in the tritium target. Thermalized 3-MeV neutrons

from a small neutron generator were used successfully in the analysis

of the metallic components of several oil-soluble organometallic Standard Reference Materials.

Determination of Oxygen in Sodium Metal—The corrosive nature

of sodium metal used as a coolant in breeder reactors is markedly

affected by oxygen content. The determination of oxygen in sodium

by conventional methods is complicated by the possibility of surface

contamination of the metal after sampling, yielding a result that is not representative of the bulk sample. In addition, the various reagents

and equipment used may contribute to the analytical blank, and this

blank may not be susceptible to accurate evaluation.

Photonuclear activation analysis, in which no blank correction need

be made, has now been applied to this determination. The reaction

utilized was ^^0(7,71)^^0. To remove surface contamination, the sample was etched after irradiation but before chemical separation and counting. A procedure to separate the radioactive oxygen from interferingsubstances in 3I/2 min was developed, and accurate determinations were achieved in spite of the very short half-life of the product nucleus

(2.1 min). Sensitivities of a few ppm and precisions of 10 to 15 percent were obtained.

Analysis of Surface Structure hy Mosshauer Spectroscopy—Because

the appropriate (Mossbauer) nuclear energy level of iron-5T decays

¥/ith a high probability of emitting conversion electrons, Mossbauereffect spectroscopy provides an interesting probe with which to examine

chemical structure of surfaces of iron bearing materials. A proportional detector has been designed to detect these —'iS keV conversion

electrons. The design has been optimized to provide the maximum

signal to background ratio. Gas-Water Chromatography—The use of aqueous solutions as the

liquid phase in gas-liquid chromatography has been developed into a

practical, rapid method of analysis. Techniques have been developed

to compensate for the tendency of the solutions to volatilize during

the analysis, and thus change composition. As a result, the vast body

86
of information on equilibria in water solutions can be applied to the

design of chromatographic columns. Effective separation of the deuterated ethylenes C2D4, C2H2D2 from C2H4 has been achieved. The

technique also can be used to determine gas-water partition coefficients and equilibrium constants for reactions occurring in aqueous solutions.

Mechanism of Steric Exclusion Ghromatogra'phy—Steric exclusion

chromatography, also called gel filtration or gel permeation chromatography, has in recent years become a pow^erful tool for the sepa- ration and analysis of large molecular species such as synthetic highpolymers, biopolymers, viruses, etc. Although widely applied, the

precise mechanism of the separation process is not fully understood.

This is partly due to the difficulties in measuring the pore size distri- bution of the gels which so far have been used with the method. By

replacing the gels with glasses of precisely controlled and measurable

pore size, the separation process was studied under controlled conditions. The results challenge the validity of the two presently most

popular separation theories. The use of porous glass as separation

medium is of further value to test present theories of the molecular

conformation of macromolecules in solution.

Long range Atomic Ordering in Platinun-group Alloys^—In many

alloys containing two or more metals, the atoms of each element tend

to occupy special positions over large regions within the crystalline

lattice. This behavior can usually be produced by an appropriate heattreatment at relatively low temperatures. The alloy is then described

as possessing long-range atomic ordering. The extent of long-range

atomic ordering can be measured by studying the relative intensities

of x-ray beams diffracted by the crystal. A comprehensive study of the

degree of long-range atomic ordering in a variety of binary alloys con- taining metals of the platinum family has revealed that the location

of a given element in the periodic table can be related to its tendency

toward atomic ordering.

The degree of long-range atomic ordering in an alloy often has a very significant effect on the mechanical properties of the alloy ; particularly its strength and hardness. By intentionally varying the degree of atomic ordering, one can obtain desirable properties in dental

gold alloys for example.

In a recent cooperative study with other laboratories it was found

that changes in the degree of atomic ordering also produce significant

changes in the temperature at which certain metal compounds (A15

phases) lose their electrical resistance completely and become superconductors. This discovery may have important implications since

there is presently an intensive effort in many countries to develop

alloys which would permit the economic utilization of superconductors

to transmit electrical power. A basic understanding of the factors

which control atomic ordering may permit the attainment of this goal.

87
It ma}^ also lielp to improve the properties of alloys now being used

for dental and medical applications.

Low Angle X-Ray Diffraction Intensities in N-Paraffiiis—Problems

concerning the structure and thermal behavior of the interlamellar

regions of crystalline chain-folded polymers and ?i-i)araffins have been

studied with x-ray diffraction teclmiques. The x-ray diffraction from

the crystalline ?i-paraiBiis, C36H74, C44H90, and C94H190, was examined

at small angles as a function of temperature. The Bragg maxima

(^Zoo ) that occur at low angles result from a lamellar repeat distance

which depends on the molecular length. In general, the intensity of

these maxima was found to increase with increasing temperature in an

approximately reversible manner. All the samples experienced solid- solid phase transitions in the temperature range of observation. Several possible mechanisms consistent with the temperature dependence

of the intensity have been analyzed.

Polyioater—In a collaborative study with the University of Maryland, a different form of water has been verified and has been shown

to have a unique molecular structure. The interpretation of the in- frared and Eaman spectra indicates that this material is a stable polymer consisting of ordinary water molecules. This new form of

water has been named polywater. Polywater has properties remarkably different from those of normal

water. Although polywater maintains the same chemical composition,

it has a thermal stability to temperatures of the order of 500 °C; has

a very low vapor pressure ; has a density about 40 percent higher than

ordinary water, and begins to solidify at —50 °C or lower to a glasslike state. Several molecular structures for polywater have been proposed.

These structures are consistent with the infrared and Raman spectra

as well as with the properties, bonding, and the stability of the material. The infrared spectrum is unique: the O—H stretching bands

prominent in normal water are absent and two new strong bands

appear. One of the proposed structures shows that the O—H—O units are arranged in a plane and form hexagonal rings.

Crystallograi^liy of Calcium Phosfliates and Related Comijounds—

Phosphorus in general and calcium phosphates in particular are very

important in the life of vertebrates. Among the calcium phosphates

fomid in the human body, either as skeletal material or pathological

deposits, are Ca5(P04)3(F, OH), CasH,(P04)6-5H20, ^Q^^{VO,)^_

and CaHP04-2HoO. CaHP04 and aCa3( P04)2 are other important

and relevant structures. The structures of aCa.s (PO4) 2 and /^Cas (PO4) 2 are unknown and may be extremely difficult to determine. The crystal structures of the related compounds Ca5(P04)3Si04 and Ca4Mg5

(P04)6 were determined. These structures apparently have close and

revealing relationships to Ca5(P04)3(F, OH) and K3Na(S04)2, ii^ 88
Proposed structures for polywater are discussed by members of the NBS

University of Maryland team investigating this material.

the case of Ca5(P04)2Si04 and to K3Na( 804)2, aCa3(P04)2, and

/5Ca3 (PO4) 2 in the case of Ca4Mg5 (PO4) e- Analysis of the Shapes of Polycyclic Carbohydrate Molecules—

The shapes of organic molecules are important to an understanding

of their reactions. Most carbohydrates occur in cyclic nonplanar forms,

but the forces that determine which of several different possible shapes

each favors are not well understood. In this work, the shapes of

sugar molecules formed by joining together several rings composed of

five or six atoms have been studied by nuclear magnetic resonance

techniques with computer analysis of the data. Assignment of the

total shape of the molecules was aided by newly developed mechanisms,

by which an excited nucleus can transfer radiofrequency energy to other nearby nuclei. The results show that electrostatic forces have

an important influence on molecular shape.

Determination of Crosslinhed Organic Networks—Three-dimensional organic network polymers have been available for several

decades, but there have been serious impediments to tlie determina89
tion of their molecular structures. The copolymers of styrene and

divinylbenzene are intermediates in the preparation of the derivative

ion-exchange materials. Previously, it has been impossible to measure

the styrene/divinylbenzene ratio after these compounds have reacted

together. This problem has been solved by studying the infrared

spectra of the copolymers. Comparison was made to similar spectra

taken of NBS Standard Reference Material No. Y05, polystyrene.

The study revealed the presence of aromatic hydrogen (out-of-plane

bending) vibrations, and these features have been identified with the

corresponding divinylbenzene cross-linking agent. Measurement of

cross-linking in the copolymer is thus feasible, and high-speed computation methods are being developed in order to do this with high

accuracy. Reduced Grystaliographic Cells—Methods to obtain a unique re- duced cell, once the three shortest noncoplanar lattice translations are known, have been developed in this laboratory. This work was

undertaken because in addition to their theoretical interest, reduced

cells have two important applications in crystallography: (a) they

make it possible to determine the Bravais lattice from an arbitrary

primitive cell of the lattice, (b) they provide a method for the clas- sification of crystalline substances.

(a) Determination of the Bravais Lattice—If any primitive reciprocal cell can be derived from the x-ray diffraction patterns, then the

corresponding direct cell, which is also primitive, can be reduced.

The Bravais lattice can be determined from a table which relates the

44 reduced cell types to the Bravais lattices. The use of the reduced

cells saves much of the preliminary work normally needed in crystal- structure analysis. The application of the reduced-cell concept be- comes especially useful when crystals are grown and studied under

special conditions, such as high pressure and high or low temperature,

when it is difficult or impossible to determine the lattice symmetry

by conventional means. Reduced cells will be applied to high-pressure

diffraction studies and to the determination of crystal symmetry with

computer-controlled diffractometers.

(b) Classification of Crystalline Substances—The present deter- minative listing of cr^^stalline substances is made on the basis of cell dimensions within each crystal system. The choice of a conventional

cell dictated by lattice symmetry is possible in all crystal systems

except triclinic and monoclinic. The use of the reduced cell, however,

makes it possible to classify uniquely all crystals including those crystallizing in the triclinic and monoclinic systems. The use of reduced

cells has been applied to triclinic crystals.

Single-Crystal X-Ray Diffraction at High Pressure—The first suc- cessful structure determination by single-crystal diffraction techniques

of a high-pressure polymorph in its region of stability has been com- 90
pleted. The study was conducted on benzene, an extremely important

chemical material. Benzene is a liquid under ordinary conditions but

crystallizes at about 5 °C. at ordinary pressure. The structure of this

crystalline form has been studied extensively at low temperatures by

conventional x-ray and neutron diffraction techniques. The crystal is orthorhombic and has a surprisingly complex arrangement of benzene

rings. Benzene can be crystallized at room temperature at about

0.6 kbar and it was found that the crystal structure is the same as that

obtained at low temperatures. This form is denoted benzene-I. If the

pressure is raised on benzene-I, it transforms above 12 kbar to a denser

crystalline form known as benzene-II Avhich is stable only under

high pressures. This crystal was the object of the present studies.

Single crystals of benzene-II were grown in the beryllium high-pressure diamond anvil cell and studied by precession x-ray diffraction

techniques. Considerable effort was expended in an unsuccessful at- tempt to find the structure of the first crystal of benzene-II. The lack

of success forced the conclusion that the intensity data should be

checked using a different crystal. Several new crystals of benzene-II were grown and studied and although all crystals showed similar reciprocal lattice networks, the first crystal appeared to have a higher symmetry than subsequent ones. It was concluded that the original crystal was highly twinned. Data from the other crystals showed benzene-II

to be monoclinic and the structure was readily obtained using computer techniques developed for use on the original crystal. In the new

structure the benzene rings are packed more tightly than in benzene-I

and are oriented more nearly parallel. The structure obtained by the

diffraction studies was shown to be that arrangement producing the

lowest repulsive energy between the closely packed rings. The struc- ture obtained could not have been deduced by any other available techniques—i.e., powder diffraction—because of the low crystal symmetry

and the low scattering-power of the benzene molecule.

Accurate Cell Parameter Data from Small Single Crystals—An

existing x-ray diffractometer has been extensively modified to facili- tate making more accurate cell parameter measurements than can normally be made with small (0.1 mm) single crystals. Because the in- strument is intended for use with "ordinary" crystals which generally

have sufficient mosaic character to limit the attainable precision, very

high accuracy is not expected. The real value of the modification is in

preparing crystals for intensity measurements with the automatic dif- fractometer. In this way the need for using the latter instrument for

time-consuming hand measurements in order to establish cell parameters and orientation can be eliminated. Specimen temperature control

is planned which will facilitate measurements of anisotropic thermal

expansion on a wide variety of crystals. Use of a diamond-anvil highpressure cell for measurements of cell parameters as a function of pres- sure is also being considered.

375-572;—70I 7 91
X-Ray Poioder Diffraction Data—A program for the calculation

of x-ray powder patterns has been started at IMR, and is part of the

project for extending and improving data for use in the identification

of crystalline phases. Patterns are calculated when it is impractical

to produce experimental data because of the nonavailability of a good

sample or because of experimental difficulties. Using the published

data from the general literature, the <i-spacings and relative intensities are calculated. The intensities are computed as relative peak heights and simulate

closely those results which would be obtained experimentally with a diffractometer and Cu radiation. Calculations are only made from

highly reliable structural data. The results are published in the NBS

Monograph Series of Standard X-ray Diffraction Powder Patterns

and are also included in the Powder Diffraction File of the American

Society for Testing and Materials.

Electron Microscopy of Rochs—Geologists studying the mechanics

of deformation of rocks from the earth or the moon have used optical

microscopy to observe deformation textures in their materials. In

collaboration with the Geology Department of U.C.L.A,, the

feasibility of using transmission electron microscopy for studying

geological materials was explored. The experimental conditions

simulating rock deformation involve testing under high confining

pressures and elevated temperatures. With brittle materials such as quartz, the test specimens and also the natural samples often are frac- tured and recrystallized indicating severe deformation. In order to prepare samples for study by electron microscopy, special thinning

techniques were needed. Such techniques have been developed and

used for many ceramic materials at NBS. By using ion bombardment,

thin foils suitable for transmission electron microscopy were prepared

from petrographic thin sections. Dislocation arrangements associated

with plastic deformation in quartz rocks were observed directly ; and some of the results were compared with observations made by optical

microscopy.

Effect of Impurities on the Crystal Structure of Tantalum

Pentoxide—Oxide compositions containing tantalum and other cations

of similar size have been investigated at high temperatures. The smallest cations have been found to stabilize low temperature forms of

TasOs whereas slightly larger cations were found to stabilize the high

temperature polymorph. Crystal structure analysis of the high-temperature form has revealed a completely new structure type. The

crystal structure of the low-temperature form was found to be dependent upon the amount of smaller cations added to Ta^Os and upon the

total stoichiometry. Both play an important role in determining the

number and type of polyhedra necessary to make up a unit cell. 92
Lattice Defects in ALOs Transmission Electron Microscopy—

At low temperatures aluminum oxide is generally regarded as a purely

brittle material with plastic deformation due to the generation and

movement of dislocations possible only at temperatures in excess of

900 °C. However, by using an argon ion-bombardment technique to thin specimens in a controlled manner for examination in the electron

microscope, it has been shown that plastic deformation does occur under hardness indentations at room temperature and that mechanical

polishing introduces a high density of dislocations within a surface

layer less than one micron thick. Direct evidence for plastic deformation at temperatures less than 900 °C has not been reported previously.

Although the large-range movement of dislocations does not appear

possible at low temperatures, the presence of such high densities of

dislocations in the surface regions of mechanically polished single and

polycrystalline samples of aluminum oxide is expected to alter their

mechanical, optical, and chemical properties and, therefore, must be

taken into consideration.

Because of their relatively high strength and chemical inertness even at high temperatures, ceramic materials such as aluminum oxide

are important structural materials. Studies on the mechanical properties are, therefore, essential and a more complete understanding of

these properties can be obtained by detailed investigations of lattice defects, such as dislocations, and their role in the deformation process. Since lattice defects also affect the optical properties, these studies are important to materials with laser applications.

Nevj Diffraction Theory for Imperfect Crystals—A crystal which

contains imperfections—such as dislocations, defects and impurities

diffracts xrays to give fine structure detail in the diffracted beams

which represents topographic images of the imperfections. The in- tensity of the diffracted beams also changes from the dynamical value

to the kinematical value (known as the extinction effect), depending

on the degree of crystal imperfection.

Until recently there has been no theory to explain the topographic

images and the change in diffraction intensities (the extinction effect)

in terms of the properties of existing imperfections. For example, the

existing extinction theory requires the famous mosaic block model to represent crystal imperfections.

A new dynamical diffraction theory for imperfect crystals has been

developed by IMR scientists. The theory has been derived from a quite

general view of scattering. The ordinary dynamical theory, which is valid only for a perfect crystal, is merely a special case in this new

dynamical theory of diffraction. Establishing such a theory is important, not only for determining the properties of crystal imperfections

in a real crystal, but for crystal-structure determination with single

crystals, where the extinction effect is the most difficult factor to estimate.

93
Cliaracterization of a Hexagonal Alloy—A series of hexagonal

silver-till alloys has recently been characterized in terms of the defect

dislocation structures and the stacking fault energy, using the technique of transmission electron microscopy. The electron microscope

permits the direct observation of individual dislocations and stacking

faults. Alloys having several different compositions were plastically

An example of the dislocation structures found on close-packed crystal planes in a silver-tin hexagonal alloy is seen in this transmission electron micrograph.

Several examples of close-spaced dislocation multipoles are present, interact- ing with two distinct sequences of glide dislocations produced by plastic deformation. 7l/=30.OOOX.

94
deformed to introduce dislocations, then examined. Tlie studies con- centrated on the variation in stacking faults energy with alloying, and

on the importance of the several different dislocation glide systems

that operate. Interactions betwen different groups of dislocations were

studied and the results interpreted in terms of the known mechanical

behavior.

Dislocations in Crystals—One way in which dislocations contribute

to the mechanical properties of materials is as sources of residual or

internal stress. A general theory of static sources of internal stress has

been developed for finite anisotropic elastic bodies, including struc- tures with complex topology. Using a projection formalism, the

stresses and strains due to dislocations and "welded in" sources of

internal stress have been calculated.

Another crystalline defect, a source of internal stress of somewhat

higher complexity than the dislocation, is the disclination. A linear

continuum theory of continuous distributions of static disclinations

has been developed for the first time. This theory also relates to other

developments in continuum mechanics.

STANDARD REFERENCE MATERIALS

From a beginning in 1906 with four standard samples of cast iron,

the NBS Standard Reference Materials Program, which made the

United States the first country with a national program of this kind,

has grown to the point that almost 700 different SRM's are now produced or are nearing completion. These include 8 new categories available for the first time this year—labelled organic compounds,

electrical and magnetic standards, ion activity standards, electron

microprobe standards, certified analyzed liquids, high-purity metal

standards, certified gas standards, and electronic and magnetic al- loys—in addition to the 70 categories already available. These are the

result of the continuing effort to keep the Standard Reference Materials program abreast of the growing and changing needs of the

times.

This year has been one of continued growth and expansion of the

SRM program. Maintaining a balance between providing renewal

SRM's for industries which now rely heavily on SRM's, and responding to new national needs in areas such as health, air and water pollution, resources development and the like, has been difficult. That some

balance has been achieved is indicated by the fact that during 1068,

66 new and Y4 renewal SRM's were issued, and 54 SRM's were dis- continued because the need for them had diminished or new SRM's

were judged to better serve the overall interests of the Nation's science

and technology. There were in stock at the end of 1968, 651 different

items in 59 distinct categories totaling over 380,000 units. Work in

95
progress to produce 318 new and renewal SRM's was centered in 146

projects. Sales during this calendar year to 8,000 customers totalled

just over $1,000,000.

Examples which follow have been selected from the 41: new and

21 renewal SEM's completed and certified during fiscal year 1969 by

13 teclinical divisions of NBS.

High-Piirity Metals—8RM 685—a new high-purity gold SKM was

issued in wire form for spark-source spectrometry, in rod form for

other methods of characterization and for reserach which requires a high-purity, homogenous standard material.

A high-purity gold vapor pressure SRM (SEM 745) also was issued

for which the vapor pressure was accurately determined over the

pressure range of 10- ^ to 10"^ atmospheres and over the temperature

range 1300-2100 °K.

The high-purity gold is issued with a Certificate of Analysis which

gives "state of the art" information on the chemical composition, in- cluding values for coper, indium, iron, oxygen, and silver. Estimated

limits of concentration are provided for 21 other elements which were

detected by spark-source mass spectrometry. Extensive homogeneity

testing was performed to establish that the gold was satisfactory

within the precision of the analytical methods used. These included

neutron activation, polarography, spectrophotometry, spark-source mass spectrometry, isotope dilution, and vacuum fusion in addition to optical emission spectrochemical analysis and residual resistivity ratio

measurements.

The gold vapor-pressure SEM represents the first in a series of ele- ments which will be certified for vapor pressure in the 10"^ to 10"^ atmosphere range. The series will cover the temperature range 600 to 3000° K.

In the field of high-temperature vapor pressure measurements there

has been a need for standards. It is not uncommon for vapor-pressure

measurements made by experienced investigators to differ by 30 percent, 50 percent, or even 100 percent. The gold vapor-pressure SEM

was developed for use in the testing and calibration of vapor-pressure

measurement apparatus and techniques, and for use in the detection

of possible systematic errors. It also can be used for direct interlaboratory comparisons. The homogeneity of the gold was confirmed by

extensive testing.

Biomedical Standards : SRM 912, 913, 9U, 915—Fouv additional

ISTBS Standard Eeference Materials were certified as chemicals of

known purity for use in calibration and standardization of procedures

used in clinical laboratories. These supplement cholesterol, which was made available previously. The new SEM's are : urea, certified at 99.7 percent purity ; uric acid, certified at 99.7 percent purity ; creatinine,

certified at 99.8 percent purity, and calcium carbonate, certified at 99.9 96
percent purity. The value of the purity of each of these SEM's has an

estimated inaccuracy of 0.1 percent.

The homogeneity of each of the lots from which these standards were prepared was tested and proved satisfactory by chromatographic

and spectrometric techniques. These methods also showed the materials to be free of measurable amounts of organic impurities, with

the exception of a small amount (<0.07 percent) of biuret in the

urea. Spectrometric analyses of the ash obtained from each of the first three of these SEM's indicated only minor concentrations of the several

metallic elements found. These results were substantiated by neutron

activation analyses of the bulk materials.

The purities of the urea and creatinine were determined by phasesolubility analysis, and for the former, was also confirmed by differ- ential-scanning calorimetry. The purity of the creatinine was further

evaluated by setting limits on amounts of possible impurities that

would be undetected by the chromatographic and spectrometric techniques employed. No organic impurities could be detected in the uric

acid even after the application of techniques that should have con- centrated the impurities, had they been present.

The calcium carbonate is a very high-purity material intended for use as a standard for all clinical determinations of calcium. Like the

other four SEM's in the series it was prepared at the request of the

College of American Pathologists and the American Association of

Clinical Chemists. They placed a high priority on the certification

and issuance of the calcium standard.

The rapid and accurate analysis of calcium in serum is an important

clinical test. Hypercalcemia, when supported by other clinical evidence,

is often indicative of hyperparathyroidism, and medical decisions in- volving immediate surgery are often made on the basis of the serum

calcium value. The imperative need for accurate calcium determinations is obvious.

In clinical procedures, calicum is determined, usually as a calciumfluorescent complex, by fluorometry, by flame emission, or by atomic

absorption methods. The NBS calcium carbonate SEM will serve as the primary standard for the calibration of the instruments and

methods used.

The material was examined for compliance with the specifications

for reagent-grade calcium carbonate as given in Reagent Chemicals^

4th edition, published by the American Chemical Society. The material was found to meet or exceed the minimum requirements in every

respect. Examination by thermal gravimetric analysis indicated the

loss of a minute proportion of weight below 175 °C (volatile matter),

and the composition was stable above this temperature up to a temperature of 625 °C, above which decomposition (evolution of CO2) set in. 97
Keplicate samples taken from a randomly selected region of the

nndried material were assayed by a conlometric acidimetric procedure. The results from nine independent determinations, based on

expression of the assay as calcium carbonate, indicate a purity of

99.99+ percent with a standard deviation of 0.003 percent. Samples

equilibrated at a relative humidity of 90 percent and assayed by this

conlometric procedure showed a maximum moisture absorption of

0.02 percent as compared to samples that were dried for 6 hours at 210 °C. The moisture content on samples equilibrated at 75 percent

relative humidity was found to be 0.01 percent. This water content was determinated by the Karl Fischer method.

A semiquantitative survey for trace contaminants by emission

spectroscopy indicated the presence of less than 0.001 percent of copper,

iron, magnesium, manganese, and silicon in the material. By atomic

absorption, magnesium was evaluated at 1.0, sodium at 0.4, and

strontium 2.1 ppm ; potassium was less than 0.4, lithium less than 0.05,

and barium much less than 10 ppm. Xeutron activation analysis indicated copper 0.9, manganese 0.6, and sodium 0.5 ppm. Copper was

determined at 1 ppm by spectrophotometry.

Electronic and Magnetic Alloy Standards: SRM 1159. 1160—Two

new nickel-base SRM's—widely used in the electronic and magnetic

industries—were made available. One is a nominal 49 percent nickel,

balance iron alloy, and the other is a nominal 80 percent nickel, 4 per- cent molybdenum, balance iron alloy.

These two new SRM's were issued meet a serious deficiency of standards for both producer and consumer of electronic and magnetic alloys. It is estimated that by 1975 the use, e.g., of permanent magnets will

double from the present annual $50 million market. Permanent magnets are in wide use in such applications as battery operated hand tools for home use, motorized garden and kitchen equipment, etc. These applications and others, where permanent-magnet motors are preferred

for reasons of reliability and efficiency, are on a steeply rising growth

curve. Designed primarily for calibration in optical emission and x-ray

spectrometric methods of analysis, the standards were issued in disk

form 11/4 in. (3.1 cm) in diameter and % in. (1.9 cm) thick. Lathe chips

may easily be prepared from the disks in the user's laboratories, if desired, for checking chemical methods of analysis both for production

control and for customer acceptance.

The material for the standards was prepared in a vacuum induction

furnace and supplied to NBS in final form following a scheme of

fabrication designed to produce material of the highest possible

homogeneity.

Extensive homogeneity testing was performed in the Institute for

Materials Research, and both materials were found to be satisfactory

within the limits of precision of the anal3i:ical methods employed.

98
The standards were issued with a Provisional Certificate of Analysis

certified for carbon, manganese, phosphorus, sulfur, silicon, copper,

jiickel, chromium, molybdenum, cobalt, and iron.

Ferrous Materials Standards: SRM 178, 1093, 109J^, SJ^O—k. new

chip-form carbon steel SEM was the first steel made by the basic oxygen

furnace process to be certified. Two new steel SRM's were certified for

oxygen and nitrogen and a new ferroalloy ferroniobium for niobium

and other elements of interest. The basic oxygen steel is a plain carbon grade. This was the first type to be certified by NBS as Standard Reference Materials. These

first SRM's included steels produced by the acid Bessemer, the acid

open-hearth, and the basic open-hearth furnace processes. A strong

demand for these standards has existed for a period of more than 60

years, and has increased rapidly in recent years. The more stringent

chemical-composition specifications in the steel industry and new, more

rapid kinds of analytical equipment that rely on comparison techniques with standards of known composition are responsible for this

demand. Furthermore, the demand is expected to grow with the con- tinuing growth in use of both the basic oxygen furnace and the con- tinuous-casting processes of steel manufacture. These relatively new

commercial processes place urgent demands on the analytical laboratory for data within a very short elapsed time from sampling to the

reporting of the final analysis.

The primary consideration in preparing steel Standard Reference

Materials is the resultant chemical composition of the steel, not the

method by which the steel is produced. This is fortunate, for in the

United States, the acid open-hearth process is no longer used commercially, the use of the acid Bessemer process is rapidly diminishing,

and the basic open-hearth is being superseded or supplemented by

basic oxygen and electric furnaces. In the near future, steel for pre- paring renewal standards of the plain carbon steels may be available

most readily from the basic oxygen furnace process. The new SRM 1Y8, chip form, carbon steel is intended for the same

purposes for which the Acid Open Hearth Steel SRM 20f was used.

The role of oxygen and nitrogen as they affect the basic properties

of metals—e.g., brittleness, ductility, etc.,—is well established. A

maraging steel can be produced which is dimensionally stable; oxygen

present as inclusions affect this stability, especially in high pressure

applications. It is therefore important that SRM's be available witli known oxygen and nitrogen content to calibrate the various instruments or methods now used to determine these gases. The two new SRM's certified for oxygen, SRM 1093 and SRM

1094, also have supplemental information given on the nitrogen content. A revised certificate of analysis was issued for SRM 1090, Oxygen in Ingot Iron, SRM 1091, Oxygen in Stainless Steels, and SRM

99
1092, Oxygen in Yacnuni Melted Steel. For these three SEM's, oxygen

values obtained by neutron activation and inert-gas fusion are included

to support the values obtained by vacuum fusion and used on the previously issued certificate of analysis.

SEM 1093, with a value of 60 ±5 ppm for ox^^gen (certified) and

a nitrogen value of 480T±10 ppni (not certified), is intended primarily for use as a standard for the neutron activation method for

determining oxygen in steel. The oxygen was determined in a 2-mchlength of rod cleaned ultrasonically for 30 min in trichlorethylene,

then dried m dry nitrogen. The rods were activated, together with

standards of known oxygen concentration, in the XBS 14 ^leV neutron

generator. (7.2 s half-life) formed from the ^®0(n,p)^^]^ nuclear

reaction was comited and the induced radioactivity compared to that

of the irradiated standard.

The determination of oxygen in this particular steel by vacumn

or inert-gas fusion is difficult because of the gettering action of the

manganese which is of the order of 9 to 10 percent.

Although not certified at this time, nitrogen at 4807 ±10 ppm was

determined by a pressure bomb-distillation-indophenol-titrimetric

method. Determmation by vacuum fusion gave a value of 351:0±76

ppm of nitrogen. It is believed that the liigher value is the more

accurate. The maraging steel, SR]M 1094, is mtended for the determination

of oxygen. The low value of oxygen, 4±0.4 ppm, makes determination

by neutron activation difficult; present configuration of the NBS

neutron generator precludes an accurate determination of oxygen at

this level. Redesign of the equipment to increase the sensitivity of the

teclinique at these low levels is now underway at NBS.

The vacuum-fusion oxygen value is the result of 60 determinations on 12 samples of the standard. One-gram samples were carefully cut from the rod material, cleaned, washed and dried. A furnace temperature of 1675 °C and a vacuum of <10~° torr was maintained during the

4 min collection time from a high-purity nickel bath.

The nitrogen content, not certified at this time, was found to be

70.7iii3.2 and 61±1 ppm for the pressure bomb-distillationindophenol-j)hotometric method and vacuum fusion teclmique,

respectively.

Three SEM's—1090, 1091, and 1092—were certified for oxygen m

March 1966. Smce that time the inert-gas fusion and neutron activation methods have been studied and applied to the analysis of oxygen

in these three SEM's. The results of this study are summarized on a

revised certificate of analysis, together with the certified oxygen values,

which remain essentially michanged, but which are now supported by

tlie additional analyses provided by the aforementioned methods.

Additional information on the nitrogen values of these three SEM's

100
is also provided, but the values were not certified. The nitrogen values were arrived at by four different analytical methods.

From the nitrogen results on the five SRM's, it was apparent that

systematic biases exist in one or more or possibly all of the methods

used for determining nitrogen. There was some evidence that nitrogen results by one or more of the methods are material-dependent.

The complexity and magnitude of this effect is not now known. A

comprehensive research effort is underway at NBS to resolve this

question and to search out other possible systematic errors. When

this research is completed these standards will be certified for their

nitrogen contents. At the request of the ferroalloy producers and Division F of ASTM

Committee E-3, a ferroniobium, SRM 340, was prepared. The new SRM complements the list of other steel-making alloys that are available from NBS. Ferroniobium is an important innoculant in the steel production process, which is finding increasing use not only in stainless

steel as a carbide-stabilizing element but also in carbon steels for purposes of hardenability. The ferroniobium standard certified as to its chemical composition is vitally important to the iron and steel in- dustry since the ferroalloys are largely bought and sold on a contained

basis for the alloy constituent. On the basis of analyses performed by

NBS and by a number of cooperating laboratories, the new SRM is certified for niobium, tantalum, titanium, carbon, manganese, phosphorus, and silicon. Computer Amplitude Reference Tape Standard: SRM 3200—An

amplitude reference magnetic tape for use in the signal amplitude

calibration of computer tape standard recording and reproducing

systems was made available as a new SRM.

The characteristics of present-day magnetic computer tapes are the

result of long-term research and development by the magnetic tape

industry. Technological developments in related fields, and trans- ducer-tape interplay, have stimulated continuing improvement of the

tape media and its performance. This has often led to differences in

tape characteristics and marginal operation when tapes are interchanged between systems. The only tapes previously available for

quality assurance purposes have been industry-supplied standards.

At the request of industrial users of computer tape, Government

procurement agencies, producers of magnetic computer tapes, and

producers of tape-handling equipment, NBS has developed tapemeasurement methods and will supply a "Secondary Standard Magnetic Tape-Computer Amplitude Reference," through the NBS Office of Standard Reference Materials.

This new material, consists of a 600-ft length of secondary reference

tape, applicable test and calibration data, and a description of the

equipment and procedures employed for measurement of the tape.

101
The secondary tapes tliemseh'es are lo-in wide unrecorded magnetic

compnter tapes wound on 8i o-in diameter precision reels. Each tape will be calibrated in terms of 100 percent signal level,

referred to the NBS Master Standard Magnetic Tape—Computer

AmiDlitude Reference, which will be kept m rej)ositorT at XBS. This

signal-level calibration will be made at recording densities of 200, 556. 800, and 3200 flux reversals per inch, and calibration information in the form of signal output charts recorded near each edge and at the center will accompany each tape. A set of saturation curves relating

the reproduce head output voltage (on the first read-after-write pass)

to the write current at each bit density of both the XBS blaster and

each secondary tape will also be included. The write ctirrent will

range from zero to at least 150 percent of the saturation current le^'el. The measurement processes are being described in an XBS Special

Publication.

Presently, the main criteria for the selection of amplitude refer- ence tapes for calibration as secondaries are signal-amplitude tini- formity and i^roximity of read-after-write output voltage to that of

the Master. The mstantaneous track-to-track variation in the average

signal amplitude is limited to a maximum of 3 percent among the

outputs from the N'BS test tracks 2, 5, and 8. The location of these

tracks is defined in ANSI Document X3.22-1967. The maxunimi variation in the longitudmal average signal output voltage along each test tract is limited to 4 percent over the 600-ft^ length of tape. The absolute

value of the avearge signal amplitude from each test track is within

10 percent of the NBS Master Standard Magnetic Tape- Computer

Amplitude Reference. These criteria are apj)lied for saturation current recording on degaussed (fully AC-erased) tape only.

Plutonkim Assay Standard: SRM -944—The Office of Standard

Reference Materials made available a new standard reference material, plutonium sulfate tetrahydrate, containing 17.50 percent of plutonium. This material was issued to provide a secondary standard for

the assay of plutonium materials to supplement the presently issued

plutonium metal standard. Each unit of the new SRM contains the

equivalent of 0.5 g of plutonimn.

Plutonium is a fissile material having impact on peaceful uses, particularly in power reactors, as well as military applications, of

nuclear energ}-. Accountability problems are especially severe and will

become even more so with the passage of time. The estimated inventorv

of plutonium by 1973 from domestic licensed facilities is 12.200 Kg.

Because of the stringent requirements for handling plutonium metal,

the plutonimn sulfate should prove to be particularly attractive for

assay work requiring an accuracy of the order of 0.1 percent. The

material is relatively insensitive to humidity at room-temperature

over the range from 0 to 90 percent relative humidity, and provides a 102
solid from which appropriate-sized subsamples can be weighed easily

for any particular use. Electron Microprohe and Microchemical Standards: RM

JfSl^ ^82—The first three standards designated specifically for application to electron probe microanalysis were issued by the Office of

Standard Eeference Materials.

The first of these, a composite consisting of a tungsten-20 percent

molybdenum alloy wire core embedded in a pure molybdenum rod onto

which there had been electro-plated a layer of pure tungsten was

prepared through the use of powder metallurgy. High-purity metal

powders were used to produce a standard of the maximum homogeneity. Based upon the results of approximately 1,500 determinations of

both tungsten and molybdenum by the electron microprobe, the material was found to be of high homogeneity of about the micrometer level of spatial resolution. A number of microprobe studies on this standard were made in IME, including: (1) correction of the relative-intensity

ratios to obtain concentrations in terms of input parameter uncertainties such as mass absorption coefficients and electron backscatter

factors, and (2) effects of operating voltage on the microprobe absorption and atomic number correction.

Companion sets of six gold-silver and six gold-copper SRM's were

certified for chemical composition and homogeneity. These sets are in

wire form, 0.5 mm in diameter, and 5 cm. long, with colored coatings

to identify the individual chemical composition.

The compositions of the alloy were chosen especially for direct

calibration of the electron-probe microanalyzer for the gold-silver

and gold-copper systems and for the testing of theories of correction

calculations for electron-probe microanalysis. Because of the high

homogeneity and well-determined composition, the standards will

also be useful for other methods of microanalysis, including laser- probe and optical emission spectrometry, and spark-source mass

spectrometry.

Standard reference materials for microanalytical methods have

well-determind composition, and must be homogeneous on the microscopic level on which the analysis is performed. These sets of SRM's

now offered by NBS is the result of a two-year program, including

investigation of the compositions needed for the standards, their careful preparation, and their characterization. The materials were pre- pared from highest-purity gold, silver, and copper and the alloys were

heat-treated at NBS to obtain maximum homogeneity.

Precautions were taken to minimize contamination. The alloy standards, in the form of wires, were heat-treated at NBS to improve microhomogeneity. The pure metal standards were examined by the residual resistance ratio technique and the total of active impurities in each was estimated to be about 0.001 percent. Tlie final standards were 103
examined spectrographically for metallic impurities; no significant

impurities were found at detection limits ranging from 0.0001 to 0.010 percent.

Variation in composition along the full length of each alloy wire was investigated by electron probe microanalysis, using a specially

designed automatic data collection system for areas 25 /xm in diameter at the two ends and at two evenly spaced intermediate positions.

The observed differences in composition for the four positions, ex- pressed as the range between the highest and lowest values for each

alloy, were close to the repeatability of the method.

Homogeneity along the wires was also tested by measurement of the

residual resistance ratio. These measurements indicated that the (macroscopic) variation of composition along all standard wires did not

exceed 0.2 percent.

Variation in composition with the cross section of the wires at the

four positions along the wire was also investigated by electron probe

microanalysis. For each cross section, measurements were made along

two diagonals at right angles. On each diagonal, determinations were made at 25 points, 1 jum or less in diameter, starting and ending at approximately 25 iim from the edge. For each alloy, the element

which could be determined with the better precision was used in

the evaluation. The variations was calculated in terms of the standard

deviation for an individual determination for each traverse. The homogeneity on a microscopic scale was further investigated

by performing quantitative measurements in two-dimensional assays of 10 X 10 points on each of the four cross sections. The distance between adjacent points was 3.5 jum. This was repeated for three of

the cross sections so that 6 to 8 arrays were obtained on each alloy. Isatopic Standards and Neutron-Density Monitor: SRM 951^ SRM 952, SRM 953—Tv^o new boron isotopic SRM's—a normal boron

and a boron-10 standard—were prepared. The first is a boric acid

of high purity and homogeneity for use in calibrating equipment and

measuring the cross section of the boron -Lithium [B ('?i,«^)Li] reaction. This cross section, particularly at thermal neutron energy

(corresponding to a velocity of 2200 m/s) is one of the most important

standard neutron cross sections used to calibrate equipment that measures neutron flux density.

The new boron isotopic standard was prepared from a lot of boric

acid that is uniform in isotopic composition and that adjusts to a

stoichiometric composition after about 30 minutes exposure to normal room humidity (approximately 35-percent relative humidity).

The boric acid has an acidimetric assay of 100.00d=0.02 weight per- cent and an absolute abundance ratio of ^°B/iiB = 0.2473±0.0002.

The assay was performed by coulometric titration of samples varying in size from 0.2 to 1.0 g of boric acid, dissolved in 100 ml of a 104
preneutralized solution of 1 M in KCl and 0.Y5 M in mannitol. The

inflection-point of the potentiometric curve obtained from measure- ments with a glass-calomel electrode system was taken as the endpoint. The pH of the maximum inflection-point will vary from

approximately 7.9 to 8.5 for the range of samples sizes given above.

The titration was conducted in the absence of carbon dioxide. The

indicated tolerance is at least as large as the 95 -percent confidence

level for a single determination of any sample in the lot of material.

The average essentially indicates a boron-hydrogen ion ratio of

1.0000, as separate examination shows the material contains less than

0.001 percent of free strong acid.

The abundance ratio was determined by single filament solid- sample mass spectrometry, using the ion NasBOs"^. Mixtures of known

^°B/^^B ratio (at a 1 : 4, 1 : 1, and 4 : 1 ratio) were prepared from highpurity separated isotope solutions and were used as comparison standards. A correction was made for the ^^O/^'O ("B/^^B ratio - 0.00079)

.

The limits of error are based on 95-percent confidence limits for the means of the ratio measurements and on allowances for the known

sources of possible systematic error. The second SRM, a 95-percent boron-10 boric acid, was issued to supplement the normal boric acid and provides materials for the cali- bration of mass spectrometers at the 95-percent boron-10 level. The boric acid has an absolute abundance ratio of ^°B/^^B of 18.80,

and an acidimetric assay of 99.97 percent. The material is useful as a "spiking" material for the determination of boron by isotopic dilution, as well as for the calibration of mass spectrometers.

Many of the power reactors contain control systems involving boron,

so the material should be particularly useful in the nuclear power

field as well as in the determination of "trace element levels" in the

ferrous metals and agricultural fields. A description of the various methods used in the characterization of

the normal and boron-10 enriched boric acid SKM's is published in

full detail and available in NBS Miscellaneous Publication 260-17.

A new SRM, a cobalt in aluminum alloy, for the measurement and

standardization of neutron densities was certified. The accurate determination of thermal neutron densities is essential

in irradiation tests in obtaining a basis for comparison of neutron densities among reactors, in applying data in the design of reactors, and in understanding the mechanisms of radiation damage. Cobalt alloys,

particularly 0.1 wt percent cobalt in alimiinum, have been widely used

to measure thermal neutron densities in almost all irradiation experiments on materials. Of increasingly major importance, liowever, has

been the need for a material of the highest possible homogeneity for

which an accurate determination of the cobalt content is provided.

This SRM also will prove useful to the activation analyst for map105
ping relative variations in neutron densities along the length and

width of irradiation containers, for determining the integrated neutron

flux density (insofar as small lengths approximate a sphere), and for

determining long-term variations of the neutron density at given ir- radiation positions. For most applications, these measurements will be

made on a relative rather than an absolute basis. The neutron-Density Monitor Wire was designed to meet these

needs. It is a cobalt in aluminum wire 0.5 mm in diameter, which was

prepared using specially selected high-purity starting materials. Based

on results obtained at NBS by activation analysis and spectrophotometric analysis, the cobalt content is certified at 0.116 wt percent.

Extensive homogeneity testing of the wire was performed by a variety of methods at the NBS laboratories in Gaithersburg, Maryland, and Boulder, Colorado. The wire material selected for certifica- tion was found to be homogeneous for sample lengths of 1 mm or

longer.

Acrylonitrile—Butadiene RiMer Standard: SRM 391—For many

y^ars the Office of Standard Keference Materials has made available

to the rubber iuilustry rubbers and other materials for rubber-compounding. The SEM's currently supplied are natural rubber (NR),

two types of styrene-butadiene rubber (SBR )

, and butyl rubber (IIR)

.

A new rubber is now added to this group, namely, acrylonitrile-butadiene rubber (NBR).

This rubber is intended for use in the standardization of testing

among laboratories and as a reference rubber in quality control and

testing for resistance to deterioration by oil, gasoline, and other hydrocarbon products.

The NBR used for the new SRM contains approximately 33 per- cent combined acrylonitrile. The rubber is wrapped in polyethylene

film, and packaged in multiwall paper bags containing 25 kgs. The

uniformity of the lot was established by tests on samples taken after

each tenth packa.o;e during manufacture.

The Mooney viscosity of this rubber was determined to be 49.0 ±1.0

ML 1 + 4 (100 ^C), using a modification of ASTM Designation

D1646-68.

Compounds for evaluation were prepared in accordance with the

formulation and mixing procedure described in ASTM Designation

D15-66T for Standard Formula IF using NBS Standard Reference

Compounding Ingredients. The viscometer cure characteristics of each

compound were determined at 150 °C according to ASTM Designation D1646-68. The minimum visvosity, incipient cure time, and cure index (the time required to increase from 5 to 35 points above the

minimum) were measured.

The remainder of the compounds were vulcanized according to ASTM Designation D15-66T and measurements were made on these

106
vulcanizates for stress at 300-percent elongation, stress at failure, and

elongation at failure (ASTM D412-68), strain under a stress of 400

pounds per square inch (2.75 meganewton per square meter) (ASTM

D1456-61), and electrical resistivity [Ind. Eng. Chem. 44, 159

(1952)].

This new acrylonitrile-butadiene rubber standard complements the

other rubber and rubber-compounding SEM's available from the NBS

Office of Standard Reference Materials.

Deuterated Hydrocarhons Standards: SRM 2175, SRM 2176—T\\&

Bureau announced the availability of two new deuterated hydrocarbon SRM's, ethand-(^6 a^nd propane-l,l,l-(^3. They are certified as chemical standards and are intended primarily to aid research work

ers in the analysis of deuterated or partially deuterated hydrocarbons.

In kinetic studies (pyrolysis, photolysis, radiolysis, etc.) in which

deuterium labeling of reactants is used, partially deuterated molecules

are formed as products. In order to specify the isotopic structure of

these molecules, comparison mass spectrometric cracking patterns are determined in the same instrument in which the actual analysis of

the product is made, since each commercial instrument shows a differ- ent behavior. It is for the determination of these comparative cracking patterns that these SRM's are intended.

The deuterated hydrocarbons were prepared by the photolysis of

ketones and purified by a combination of gas chromatography,

absorption, and distillation. Chemical purity was determined by gas

chromatography and isotopic purity by mass spectrometry, and con- sideration of reactions entered into by the reagents.

The ethane-c/e has a chemical purity of greater than 99.9 mole percent; the only detectable impurity being a trace of propane. Its iso- topic purity is 99.8 ±0.05 atom percent deuterium combined as 98.9 mole percent C2D6 and 1.1 mole percent C2H5D.

The propane-l,l,l-(i3 has a chemical purity of greater than 99.9 mole

percent; the detectable impurities identified as approximately 0.03 mole percent ethane and 0.01 mole percent ethylene. Its isotopic purity

is 99.4 mole percent CD3CH0CH3 and 0.6 mole percent CDoHCH.CHo.

Cycloliexane Dielectric Constant Standard SRM 1511—NBS issued

Cyclohexane as the first of three liquids to be certified by the Office

of Standard Reference Materials for dielectric constant standards.

The dielectric constant of this material was measured at 20, 25, and

30°C and it is felt that calculated values can be used from 10 to 40°C

without introducing appreciable errors. This SRM is useful for the

determination of the geometric capacitance of two terminal dielectric constant cells and for checking the linearity of the geometric capaci- tance of the three-terminal, or absolute, cells. The dielectric constant of most materials is commonly defined and

measured as the ratio of the capacitance of a capacitor immersed in

375-572—70 8 107
the medium in question to that in vacuum. Because most test capacitors

(cells) are nonideal, for accurate work they must be calibrated using

air and one or more materials of known dielectric constant. Reference Materials for Thermochemistry: SRM 724—Determinations of the heats of solution of a standard reference material, tris (hydroxymethyl) amino methane (TRIS) were carried out in a highly precise adiabatic solution calorimeter and used for preparation of a certificate of the heating value. This reference material

(Standard Sample No. 724) is very much needed by scientific workers

in the thermochemistry of solution processes, in order to detect and

eliminate sources of systematic error. Such systematic errors have

caused numerous discrepancies among measurements made in dif- ferent laboratories. The precision of the repent measurements is somewhat better than 0.05 percent, and illustrates the quality of the

measurements that can be made with this recently developed calorimeter. Both the heat of reaction with dilute HCl (aZT negative) and

with dilute NaOH {i^H positive) have been determined, thus pro- viding comparison reactions for both endothermic and exothermic

reactions.

New Chemical Microstandard : SRM 1800—Problems encountered

in the calibration of sensitive chemical analytical instrumentation

have been resolved by a recent IMR discovery that individual ionexchange beads can be used to hold extremely small and accurately

known amounts of matter. Techniques have been developed for pre- paring beads containing from one nanogram (10"^ g) to less than a

billion atoms. The preparative methods include the use of "clean"

conditions for loading and isolating the beads. The first microstandard

Standard reference materials being prepared by tlie dispersal of chemically loaded ion-exchango beads on glass slides in a clean room. 108
has now been made available to the public. It consists of calcium ions

loaded onto cation exchange beads in amounts ranging from 10"^ to

10"^^ g. The material is designated Standard Reference Material No.

1800. Microstandards for a series of other elements are in preparation.

Oceanographic Gonductivity Standards—The electrical conductivity of sea water provides the most precise and convenient measure of

salinity available to the oceanographer. For the reliable identification of water masses and for the calculation of related properties

such as density and sound velocity, measurements of conductivity are needed with a precision comparable with that of the best research

measurements on electrolyte solutions. A series of sodium chloride

solutions of certified conductivity has been prepared for use in cali- brating oceanographic salinometers. The solutions have temperature

coefficients of conductivity sufficiently close to those of sea water to have practical utility, and yet they are more readily prepared and

characterized in terms of concentration and purity than either natural

or synthetic sea water. With conductivities known to 0.01 percent,

these reference standards are expected to find wide application in

oceanographic work.

DATA ON THE PROPERTIES OF MATERIALS

This program stresses the precise measurement of materials properties and the development of new and improved measurement techniques. It embodies experimental and theoretical investigations of

chemical and physical phenomena of importance to science and in- dustry, and seeks to correlate chemical and physical properties of

materials with their composition and structure. Atomic and Molecular Data

Infrared and Ultraviolet Spectroscopic Studies of Reactive Molecules Isolated in Inert Solid Matrices—Using matrix-isolation techniques, the stretching fundamentals of SiCla and SiCls and all of the

vibrational fundamentals of SiFa and SiFs have been observed. This

permitted an estimate of the approximate structure of these species.

In ultraviolet studies of the reaction of photolytically produced H

or D atoms with GO at cryogenic temperatures, the absorption counter- part of the hydrocarbon flame bands has been observed for the first time. The attribution of this band system to HCO has been confirmed.

Both the CO-stretching and the HCO-bending vibrations have been

found to be appreciably excited in this transition. The observation of

the ground-state vibrational fundamentals of HCO in infrared spec- troscopic studies made possible a detailed assignment of the hydrocarbon flame bands.

109
A furnace was developed for studies of the reaction of gases with

high-temperature metal surfaces. Several of the first-series transitionmetal (Cr, Mn, Fe, Co, Ni) dichlorides have been trapped in inert

solid matrices in sufficient concentration for direct observation of their

stretching fundamentals under conditions such that interactions with

neighboring dichloride molecules are virtually completely eliminated.

Two previously umeported electronic transitions have been observed

between 500 and 440 nm for NiCl2, one of them mth extensive vi- brational structure. Photolysis of matrix-trapped alkali metal atoms has provided a source of electrons in the matrix. These were used to interact with

ground state C2 species in an argon matrix to give C2. A reassignment

of the adsorptions prcAdously ascribed to the Swann transition

resulted. In a similar manner the species NO2 has been stabilized in

sufficient concentration for the driect observation of one vibrational

fundamental.

Magnetic Resonance of Copper in Rutile—The magnetic resonance spectrum of divalent copper ions in titanium dioxide (rutile) was

examined in detail. Information was gained about both isotopes of

copjDer and the interactions of the ion with the host crystal. The ex- periments determined the electronic ^-factors, magnetic hyperfine

coefficients, and the electric quadrupole coupling parameters. The

magnitudes of the quantities were obtained experimentally and the

absolute signs predicted theoretically from a model which gives a

consistent picture of the ordering of the electronic states of the copper

ion. The theory includes the effects of the orthorhombic crystal field and covalent sharing of the valence electrons of the copper.

Development of a Highly Stable Pulsed NMR Spectrometer—Scientists in IMR have recently developed an extremely stable pulsed NMR

spectrometer which has made it possible to perform meaningful CarrPurcell experiments. Such experiments are used to measure dynamic

processes in molecular systems. The spectrometer is currently being

used in a joint program by NBS and NIH scientists to study hindered

rotation in cytosine derivatives. Cytosine is one of the molecular building blocks of DXA and RNA.

Determination of ^^C Relaxation Mechanisms—In a joint research

program, IMR scientists and scientists at the Division of Computer

Research and Technology and the National Institute for Arthritis

and Metabolic Diseases (both at NIH) have for the first time made

a quantitative determination of the contribution which various relaxation mechanisms (such as direct dipole-dipole, chemical shift

anisotropy, spin-rotation, etc.) , make to the total ^^C spin-lattice relaxation time. Such information has great importance for planning ex- periments on the $200,000 super-conducting NMR spectrometer

scheduled for delivery to NIH in the autumn of 1969. Also, such in- 110
formation is of importance in checking the fundamental theories of

magnetic interactions in molecular systems.

Electronic Structure of P-F Bonds in Fluorophospliates—^Using

x-ray diffraction and NMK spectroscopy, IME, in cooperation with

University of Illinois scientists, has made it possible for the first time

to determine the sign and the magnitude of the anisotropies of both

of the chemical shift tensors (one for ^'^F and one for ^^P) and the

3ip_i9p spin-coupling tensor in the PFO^s anion. Such a determination requires a precise knowledge of the crystal structure of the fluoro- phosphate and a detailed line shape analysis of the ^^P and ^^F NMR

line shapes for spectra obtained at — 190 °C. The knowledge of the sign

and magnitude of the 3ip_i9jr gp^j-^ coupling anisotropy has resulted

in the first and only unequivocal experimental determination of the

absolute sign of an NMR spin-coupling constant. This information

is of great value both to synthetic chemists and to theoreticians

Relojxation Process of Chromium Ion in Potassium Alu/ni—The elec- tron spin relaxation process of potassium chrome alum and potassium chrome aluminum alum was investigated by measuring the change

in the static d-c magnetization as a function of the cw microwave power

absorbed at electron resonance, and also by observing the transient

recovery of the microwave resonance signal. At liquid helium temperatures the direct spin-lattice relaxation process is the dominant

rate-determining process for magnetically dilute potassium chrome

aluminum alum, but for the magnetically concentrated crystals the

spin-lattice process can easily be obscured by the lattice-bath relaxation

process. There is some evidence that the lattice-bath relaxation rate is determined by the thermal conductivity of the helium exchange medium. Within the experimental error the spin-lattice relaxation meas- urements at 14.5 GHz and those of other workers at 9 GHz are in agree- ment with the calculations made by Van Vleck in 1940. His theory

predicts that for the direct process at high fields t^TH'^ is constant where T is the temperature, ti is the direct spin-lattice relaxation time,

and H the magnetic field. The experimental values of ti agree with the

calculated to about a factor of five and the exponential of H is approximately two. The theory also predicts that, to first order, ri is isotropic

and independent of the chromium ion concentration, and this also ap- pears to be borne out experimentally.

Solid State Data

Versatile Prohe for Optical-EPR Studies—A sample EPR probe,

developed in IMK, can hold any sample material for experimental in- vestigation under varying conditions of illumination, temperature (as

low as 1.3 K), and microwave frequencies. The versatility of the new

probe will aid scientists in improving the quality of lasers, in studying

the photochromic properties of crystals, and in investigating the solid

111
state properties of crystals for prospective use in display panels and

as holograms for storage purposes.

The probe is a pipelike device that can hold any crystalline or powdered material to be investigated. One of the probe's outstanding fea- tures is a rigid but adjustable coaxial coupling system (coaxial line)

that physically and electrically connects the resonance "test" cavity

at the lower end of the line to the microwave system at the upper end,

with minimum energy losses and stray reflections. In addition to the

coaxial line, the probe consists of a microwave source, a microwave

transition coupling system, a light pipe, an iris assembly, and a reso- nance cavity.

The probe has been tested with considerable success in experiments on a double-doped ZnS : Cu, Ga crystal. NBS data on the photon absorption lines of the crystal at various magnetic field strengths and

microwave frequencies showed good agreement with results obtained on

the same crystal by other scientists. Subsequently this probe was used to study photosensitive color centers in a single crystal of calcium oxide. An EPE width of 10"^ tesla was obtained, the narrowest line width ever observed in solid samples.

Optical-microwave probe sliowing the microwave transition coupling system,

light pipe, iris assembly, and resonance cavity. The probe holds sample materials during EPR studies. 112
The increase in the production of color centers responding to excited

light, and the color centers' decay after the removal of the excited light,

could be traced by the EPR signal monitor.

Proposed Standard Reference Material for M'ossbauer Spectroscopy—A new standard material for use in Mossbauer spectroscopy has

been proposed as a result of nuclear magnetic resonance experiments

recently performed by IMR scientists. The intermetallic compound,

TiFe, possesses many advantages as a material with which to cali- brate the applied magnetic field, in ^^Fe Mossbauer experiments.

The Fe possesses a cubic symmetry, avoiding complications of quadrupole effects. The Knight shift has now been measured with good

precision by nuclear magnetic resonance. A further advantage is that

the Knight shift is nearly temperature-independent. Measurements of

internal fields at the ^Te nucleus should be more precise using this new

standard.

Luminescdnce in Semiconductors—The use of photoluminescence

and photoconductivity in the elucidation of dynamical processes was

applied to insulating strontium titanate and thallous bromide. Strontium titanate was found to exhibit a sharp emission line at 800 nm,

with 31 satellite lines arising from phonon cooperation (vibrational

sidebands). Excitation spectra show that the center responsible for

the photoemission is not directly excited by resonant-energy transfer

in which the excitation of electrons and holes is transferred to the ex- citing center by a radiationless transfer of energy. Then the excited

center decays, emitting photons and phonons.

Another process, known as Auger recombination, has been observed

in TlBr on -excitons trapped at impurities. In this process the impurity

exciton is deexcited by a spontaneous transfer of charge to the conduction band where it dissipates energy. The remaining energy at the

center is dissipated by photon and phonon emission.

Temperature dnd Pressure Dependence of Dielectric Constant of

Cadmium Fluoride—Although cadmium fluoride has a large insulatorlike energy gap of 6.0 eV, doping transforms it into a well-conducting

semiconductor. The static dielectric constant at room temperature and

pressure was determined to be 8.33 and has a positive temperature

dependence coefficient, thus agreeing with reported theories predicting

a positive coefficient for compounds with a dielectric constant of less than 10. Pressure dependence along with the temperature dependence

of the dielectric constant were combined with compressibility and

thermal-expansion coefficient to complete the picture and give inforaiation on the temperature dependence of the polarizability, as well. A

value of 0.80 at room temperature for the Szigeti charge was

calculated.

Propagation of Acoustic Phonons in Ileisenherg Paramagnets—

The propagation of sound waves in ferromagnetic and anti-ferromag113
iietic insulators has been studied within the framework of two models

w^hich describe the interaction between the spin system and the lattice. Expressions for the frequency shifts (phonon renormalizations) at high temperatures and near the transition temperature are obtained

now in terms of time-dependent correlation functions. The frequency

shifts for long-wavelength phonons are negative, increase rapidly in

the vicinity of the transition temperature, and are less singular than

the attenuation coefficients. The ratio of the frequency shift to the un- perturbed phonon frequency is independent of the phonon frequency

for long wavelengths. These results agree qualitatively with present

experiments.

Development of Loid-Threshold Laser Glasses—In a cooperative

project with the Night Vision Laboratory, U.S. Army Material Command, experimental glasses doped with various rare-earth and transition metal atoms have been made in order to evaluate their fluorescent

properties. Kadiative and nonradiative energy transfer and decay

processes have been investigated in silicate glasses codoped with Eu

and Nd. Energy transfer from Eu to Nd was established from an

examination of the excitation spectra and the increased Eu decay rates in the presence of Nd. Measurements of the concentration dependences

of the Eu+^ and Nd^^ fluorescence lifetimes reveal the presence of four

distinct processes arising from various ion-ion interactions: (1) self- quenching of the Nd^^ fluorescence, (2) self-quenching of the Eu+^

fluorescence, (3) nonradiative energy transfer from Eu+^ to Nd+^

and (4) Eu quenching of the Nd+^ fluorescence. This last process

decreases the radiative quantum efficiency of the state of Nd+^,

thus limiting the attractivness of Eu sensitization for Nd laser action.

Polarizable Ion Models for the F Center in Ionic Crystals—The

states of the F center have been considered on the basis of models which

treat the movement of the nearest neighbors to the F center and the

F electron in a self- consistent manner. The lattice is first described in

terms of a classical ionic-crystal theory. The theory has been extended

now to treat the nearest neighbor ions in a quantum mechanical manner. The one-defect electron (the F electron) is treated according to polarizable ion models. The absorption energy, the emission energy, the

lifetime of the first excited state, the zero-phonon transition energies,

and the Huang-Khys factors are evaluated for two models which differ in the rigor used to compute the polarization of the nearest and next

nearest neighbors. The model which contains the more rigorous evaluation of the polarization agrees best with the experimental results for

CaOandMgO.

Thermodynamics and Transport Data

Chemical Thermodynamics Data Center—During the past year the

Chemical Thermodynamics Data Center completed and published Part

114
4 of the Series, TN 270, "Selected Values of Chemical Thermodynamic

Properties." This volume contains values for the room-temperature

properties (heats and Gibbs energies of formation, entropy, enthalpy,

and heat capacity) for compounds of 19 elements. This is part of the

continuing NBS program on the maintenance of tables of self-consistent data in thermodynamics, and has now covered approximately

one-half of the elements in the Periodic Table.

The Data Center has also completed a comprehensive Bibliography

and Substance-Property Index of the published literature for 1968

with respect to thermodynamic measurements on inorganic compounds.

It contains over 8,000 index entries obtained from nearly 2,800 published articles and will appear in the 12th Edition of the Bulletin of

Thermodynamics and Thermochemistry, sponsored by the Commission on Thermodynamics of the International Union of Pure and

Applied Chemistry.

Ionization and Appeai^ance Potential Comqnlation—A comprehensive compilation has been prepared and published, covering ionization

potentials, appearance potentials, and heats of formation of gaseous

positive ions. These quantities are based on measurements employing

techniques of mass spectrometry, photoionization, photoelectron spec- troscopy, untraviolet spectroscopy and, in some instances, on semiempirical molecular orbital theory. The compilation covers the period

1955-1966, including information on more than 1,500 ionic species

and giving more than YOO references to work in this field. This information is of fundamental interest in all areas of gaseous ionization

phenomena.

Dissociation Energies of Fhwrine and Hydrogen Fluoride—Deter- mination of the dissociation energy of the F2 molecule has been a

difficult experimental problem. Many determinations of this quantity

have been attempted, representing a number of different experimental

techniques, and resulting in a wide range of proposed values. In

a new approach to this problem, thresholds unambigously assigned

to dissociative ionization and ion-pair formation were meas- ured with a photoionization mass spectrometer for the related

molecules F2 and HF. Although the resulting dissociation energies for both molecules are significantly smaller than previously

favored values, these new data are supported by their consistency with

the accepted heat of formation of HF. These measurements will affect the calculation of binding energies of fluorine-containing molecules.

The new results ha,ve already stimulated a reinvestigation of the emission spectrum of the IIF molecule.

Critical Phenortiena in Binary Liquid Mixtures *—To study critical phenomena in binary liquid mixtures, the system o-metliylpontane-

* In cooperation with the Institute for Basic Standards. 115
nitroetliane was selected at NBS. The refractive index of the liquid

components of this system is such as to minimize multixDle scattering

in studying critical opalescence. Experiments were carried out to determine the intensity of scattered light, the curve of coexisting concentrations, and the behavior of the surface tension as a fmiction of

temperature. Stimulated by the work at NBS, several research groups

elsewhere have initiated experimental studies to investigate other

properties for the same system.

Deuteiium Isotope Effect on the Ionization of Weak Acids—It has

long been known that acids weak in water are still weaker when dis- soved in deuterium oxide. The difference in strength, expressed as AjyK (where K is the ionization constant), varies with the acidic

strength {pK) in water in a manner thought my many to be linear. The straightline variation has been difficult to confirm, because of a

lack of precise data for the pK of a moderately strong acid such as phosphoric acid or sulfuric acid. Such data are notoriously difficult to obtain. The ionization constant of phosphoric acid, however, was

carefully measured at NBS 18 years ago and has now been determined,

using identical techniques, in deuterium oxide over a temperature

range of 5 to 50 °C. The values of l\pK thus obtained thoroughly

confirmed the linear variation, but a critical examination of the best

data for a variety of acids rcA^ealed that only inorganic acids appear to

fall uniformly on a straight line at low values of pK. Many moderately strong organic acids, on the contrary, show considerable deviations. It is concluded that the deuterium isotope effect is not as simple

as has often been assumed.

2?II Standard for Clinical Use—Changes in the acid-base balance of

blood and other biologic fluids are a useful indicator of pathological

conditions in the human body. For the most part, the region of critical interest lies between pH 6 and pH 8. Accurate pH measurement and

control has been hampered by the lack of buffer materials capable of

fixing pH in this physiologically important range of acidities. A new

buffer substance called ''^his-tris^^ (the chemical name is 2,2-5 ?-s [hydroxymethyl]-2,2'2''-nitrilotriethanol) has recently been found suitable

for pH measurement and control between pH 5.5 and 7.5. Furthermore, solutions of this substance are compatible with most biologic

fiuids. To make this buffer material most useful to clinical chemists,

the acidic dissociation of "Jz^-z^Ws" has been accurately determined

from 0 to 50° C by careful electromotive-force measurements. In

addition, the pH values of several concentrations of ^^his-tjis'' buffers were determined. As a result of this work, it is now possible to control

pH accurately in biomedical studies performed in the mildly acidic

range and to standardize pH equipment at a pH near 6.5. Standards for Ion-Selective Electrodes—The rapid increase in the

types of ion-selective electrodes made available during the past two

116
years has brought a widespread expansion in the applications of these new sensors. New uses have stimulated the demand for standards of ion

activity, the property most directly related to the response of these

electrodes. A numerical scale of individual ion activities, consistent

with the conventional scale on which the measurement of pH is based,

has now been proposed by NBS, and the certification of activity standards for sodium and chloride ions is under way. The performance of

electrodes for the determination of calcium and fluoride was evaluated

by a procedure that has been adopted for the examination of each new

type of sensor. The response is first compared with that predicted by

theoretical equation as concentration and temperature are changed.

The consistency of the response with the conventional scale of activity

is evaluated, and the magnitude of liquid-junction errors in the meas- urement of ion activity is estimated. Priorities are established through

consultation with the instrument manufacturers and users of the

electrodes. Melting Point of Aluminum Oxide—A task force on secondary

temperature standards, chaired by an NBS staff member and sponsored

by the Commission on High Temperatures and Refractories, Inter- national Union of Pure and Applied Chemistry, has completed a co- operative determination of the melting point of aluminum oxide

(AI2O3). In all, nine scientific groups representing seven countries

participated in the joint experimental effort. All work was performed

utilizing a common supply of high-purity AI2O3. Experimental techniques varied, depending upon the individual investigator. The value

for the alumina point, as recommended by the task force, is 2053° with

a standard deviation of ±4° C (IPTS 1968)

.

In addition to actively supporting the task force, NBS is now developing an AI2O3 standard reference material. The high-priority

standard sample, in 10 g lots, will have a certified melting point with an overall uncertainty of less than ±5° C. The SRM will be particularly useful in the fields of high-temperature chemistry and re- fractories for in situ temperature-calibration purposes.

Heat Capacity Adjustments for Natural Ruhher Confirmed—Recent

precise measurements have confirmed NBS proposals for adjustments

required in previously determined values of the heat capacity of

natural rubber (m-l,4-polyisoprene) near room temperature. Accurate

knowledge of this thermophysical property is essential to efficient commercial manufacturing and processing operations in the automobile-tire and other rubber industries. The original values were

determined in pioneering work at NBS in 1935. These values satisfied technological needs for several decades. However, refined industrial

operations resulting from technological progress eventually suggested

that these original values were not sufficiently accurate for thermophysical calculations required in the more advanced technological

117
processes. On the basis of new knowledge gained from basic research on polymer crystallization during the intervening decades, NBS

scientists concluded that the original measurements had been adversely

affected by undetected crystallization processes which were unknown at the time those measurements were made. By taking this new knowledge

into account, predictions were made for adjustments which needed to be applied to the 1935 values in order to obtain values sufficiently ac- curate to satisfy today's technological requirements. New heat-capacity

measurements have now been made on synthetic (rather than natural)

m-l,4-polyisoprene in an adiabatic calorimeter which covers the temperature range from 2 to 360 K with a precision of better than 0.1 percent of the values. The synthetic polymer is the result of industrial

research advances in the past decade and is considered to be tech- nologically equivalent to the natural product, over which it has valuable economic advantages. These new measurements confirm the proposed adjustments, and the basis for the thermophysical calculations

required in the rubber industry is again re-established on the basis

of firm measurements.

Diffusion in Alloys—Kinetic equations have been developed describing diffusion in a random multicomponent alloy. It has been found that

simple relations between the atom and vacancy diffusion parameters

can be calculated if the atoms and vacancies in the crystal are as- sumed to be randomly distributed and suitable averages are taken.

These relations, which should apply well to many nondilute alloys,

predict a forbidden region in the plot of diffusion coefficient ratios versus composition, and indicate a possible kinetic source of negative

diffusion coefficients. Chemical Kinetics

Theory of Chemical Kinetics—Resonant scattering theory, originally developed for atom-electron interactions, has been applied by

IMR, scientists to the description of chemically interesting collisions. The result is a complete quantum mechanical description of the interaction between molecules in decomposition and combination reactions.

Taken together with recent advances in the calculation of potential

energy surfaces, this theory provides the basis for exact calculation

of rates of chemical reactions.

High-Pressure Photoionimtion Mass Sjyectrometry—A unique

photoionization mass spectrometer has been constructed by IIVIR sci- entists for investigation of ion-molecule reactions occurring at elevated

pressures in the vapor phase. This instrument has been successfully

used to derive accurate rate constants and cross sections for the reaction

of thermal organic and inorganic ions in the pressure range 0-10 torr. Using selectively labeled deuterium-containing analogs, the stereospecificity of many of these processes has also been determined.

118
The kinetics and meclianisms of chemical reactions initiated by higii energy radiation being studied with a rare-gas resonance lamp.

Photoionization in the Far Ultraviolet—In recent years considerable information has been accumulated concerning the kinetics and

mechanisms of chemical reactions initiated by high-energy radiation,

especially in the lower-molecular-weight hydrocarbons. Earlier work

has demonstrated the feasibility of using photolysis techniques with

high-energy photon sources as a means of studying the unimolecular

decomposition of parent ions and superexcitecl molecules as well as the subsequent reactions of the fragment ions or radicals produced by

such dissociations. Numerous investigations of this type have been

carried out using krypton (1236 A, 10.0 eV) and argon resonance lamps (1067-1048 A, 11.6-11.8 eV). In order to extend such studies to

still higher energies, self-contained helium (584 A, 21.2 eV) and neon

resonance lamps (744-736 A, 16.7-16.8 eV) have now been designed,

constructed and used successfully in such experiments.

These helium and neon resonance lamps which have a high spectral

purity, a high intensity, and a long lifetime have recently been used

in several photoionization studies. The results have been compared

with the results from the gamma-ray radiolysis of the same hydrocarbons. These same resonance lamps have been used to derive ac- curate extinction coefficients and ionization quantum yields for a large

number of organic and inorganic compounds.

Decom'position of Hydrocarhons—Hydrocarbon molecules decompose at high temperatures by splitting into two free radicals by scission

119
of carbon-carbon bond. A systematic study of tlie rates of these decomposition reactions has been made using the single pulse s!hock tube

technique. It shows that the rates and mechanisms are predictably

dependent upon variations in molecular structure. As a result, a large

number of decomposition rates may be predicted from a limited set of

measurements. For example, from 9 measured decomposition rates 27

other rates have been predicted. Where cross-checks are available, the

agreement is good.

Vacuum Ultraviolet Flash Photolysis—The vacuum ultraviolet flash photolysis of carbon suboxide has been shown to produce carbon atoms

in addition to carbon monoxide. Using the method of kinetic spec- troscopy, rate constants for the reaction of carbon atoms with hydrogen, oxygen, nitrogen, nitric oxide, and methane were measured for

the first time. Rate constants for the interaction of methylene radicals

(produced from the vacuum ultraviolet flash photolysis of ketene and

cliazomethane) with hydrogen, nitrogen, and methane were also determined by this technique.

Chemical Kinetics Mass Spectrometry—Reactions of atomic oxygen

and of molecular oxygen in the lowest-lying excited state are of great

importance in air pollution, upper atmosphere chemistry, and combustion. Rate constants for atomic oxygen reactions with about 25

Vacuum ultraviolet flash photolysis apparatus used for the study of the chemical

reactivity of free radicals. 120
alkanes and bromo- and chloralkanes have been measured at temperatures from 300 to 600 K. The first measurements have been made on

the rates of reaction of excited molecular oxygen with organic com- pounds and the importance of these reactions in air pollution is under

study.

Surface Data

Neio Technique for Surface Catalysis Studies—A novel method

for observation of surface interactions has been developed. Two chemisorbed gases are completely separated, but contiguous—the zone of

interaction initially is a region only a few angstroms wide. On heating, diffusion processes can occur to widen the zone. If interdiffusion

takes place with increasing temperature, the process is visually observable. This new technique appears to have interesting applications

in studies of surface catalysis. The instrument used is the NBSdeveloped field emission microscope-molecular beam combination. A

field-emitter tip, whose axis is perpendicular to the gas beam, is cov- ered with a monolayer of gas on that half of the tip exposed to the

4 5 Field emission patterns of two separated, contiguous, chemisorbed gases (carbon

monoxide and oxygen) on tungsten : 1. Tungsten tip half-shadowed with oxygen (oxygen-covered portion not visible because of high work-function )

.

2. Carbon monoxide condensed over oxygen on tungsten (upper portion,

oxygen; lower portion, carbon monoxide).

3. Pattern after heating tip to 350 K.

4. Pattern after heating tip to 700 K for 5 minutes.

5. Field emission pattern of clean tungsten.

121
beam. A second gas is similarly condensed as a second layer. Both

depositions are done at 4.2 K. The temperature of the tip is raised to 50 K to separate the gases by surface migration, for at this temperature the second layer, but not the first, migrates. There results a monolayer over the entire tip, half of the tip covered with the first gas, the other half covered with the second gas. Ghemisorption on Single-Crystal Tungsten Surfaces—Several new

experimental methods have been developed to study the chemisorption

of gases on single-crystal tungsten surfaces. One study of hydrogen

desorption from a (100) tungsten disk involved using a focused lamp to heat the suspended crystal uniformly without introducing temperature inhomogeneities. Two distinct binding states having desorption

energies of about 25 kcal. mol"^ and 32 kcal. mol"^ were found. They

are populated at room temperature in a two-to-one ratio with full coverage. The dipole moment per adsorbed atom was found to be 0.15 Debye, independent of binding state. Coadsorption of hydrogen and

deuterium resulted in isotopic mixing in both states. Oxygen chemisorption on a (100) tungsten was followed using 0+ ion desorption stimulated by electron impact. The state from which

0+ originates occupies about %o of a monolayer at full oxygen coverage. The ion-energy distribution curves at surface temperatures be- tween 300 and 1200 K provided data leading to a characteristic vi- brational frequency of 1270 cm"^ for the state. This and other results strongly imply that the /?i state is molecularly absorbed.

Ellifsometry—The ellipsometer is an optical instrument that measures the properties of surfaces and thin films on the surface by the

changes in state of polarization of light reflected from the surfaces. Due to its sensitivity to very thin films, for examj)le, the ability to measure thickness to a few Angstrom units, it has been applied to studies of polymer absorption, corrosion of metal surfaces, etc. The errors that occur in measurements by the ellipsometer have been

analyzed and means to eliminate them derived. The errors considered

are an imperfect compensator in the ellipsometer, birefringence in a

cell containing the surface, tilting of the surface, and roughness of the

surface. A new Fortran computer program has been written to per- form the involved calculation required to analyze the ellipsometer

measurements.

Mechanical Properties

Bulk Modules of Solid Linear Polymers—^A bundle-of-chains model

has been used to predict the bulk modulus and Gruneisen parameter

of linear polymer crystals such as polyethylene and the n-paraffins.

The theory uses nearest-neighbor pair potentials to calculate the sec- ond and third derivatives of the lattice potential energy with respect

to volume. This model is expected to yield useful predictions of the

122
intermolecular thermal energy and, via the Debye equation of state, the thermal expansion coefficients for linear crystalline polymers. The

predicted Gruneisen parameters were found to be considerably larger

than for simpler molecular systems and were found to be in excellent

agreement with results for ultarsonic and specific heat measurements

on polyetheylene.

Mechanical Properties of Dental Materials—A torsion pendulum

system has been developed for determination of elastic properties and

internal friction of dental materials. The specimen serves as the tor- sion bar in the system. From the frequency of the pendulum, the shear

modulus of the specimen mateiral can be determined and from the

damping the internal friction can be measured. A value of 3 X 10^ psi (2X lO^N/m^) obtained for the shear modulus of dental amalgam

is in agreement with values obtained by ultrasonic methods. The tor- sion apparatus is applicable to many restorative materials and to natural tooth structure. Studies of the effects of temperature variations on the mechanical properties of dental materials and tooth structure

will be made with this apparatus.

Microscopic Studies of Elastic Strains in Materials—Stress-strain

analysis in local regions of polycrystalline iron-silicon transformer

sheet has been carried out using the divergent beam (kossel) x-ray

diffraction method. This nondestructive measurement technique per- mits microscopic strain determinations near grain boundaries and
other disturbed regions in the alloy and provides mapping the strain

distribution. Previous mechanical and thermal treatments of the material determine the nature of the observed strain distribution together

with the magnetic characteristics of the transformer sheet. High Cyclic Bending qf Steels—In repeated high cyclic bending,

with constant load amplitude, the size and the shape of the plastic zone preceding the propagating crack is controlled by local structural

conditions near the tip rather than by stress intensity. No significant

correlations have been found between the experimentally determined

sizes of plastic zone and the theoretically predicted values of Liu

and Rice. The plastic zone sizes ahead of the propagating crack cannot

be simply expressed as proportional to the rate of fatigue crack

propagation, though a simple relationship exists between the rate and the stress-intensity factor. The relationship given by Paris,

^=QAi^", describes the rate of crack propagation only in a limited

range of relative crack-length, x<C0.5. The extent of this range depends on the structure and on the level of applied cyclic stress. Beyond this range, the Paris equation cannot be applied and the

crack propagation cannot be related to the stress-intensity factor. Alloy Softening BCG Transition Metals—The experimental and

theoretical basis for the unusual phenomenon of "alloy softening" has

been clarified in three published papers. Alloy softening is the weakening of very pure metal deformed below a temperature of about 0.20 times the melting point upon addition of dilute concentrations of

solute. Softening in interstitial alloys is attributed to elastic interaction between interstitials and screw dislocations leading to crossslip, whereas softening in substitutional alloys is attributed primarily

to electronic interaction, i.e., modification of the <i-band density leading

to reduction of the Peierls-Nabarro energy barrier. The relationship

between alloy softening and the ductile-to-brittle behavior of bcc

transition metals is being explored in high-purity interstitial alloys

of iron.

Microplasticity in Metals—Microplasticity studies at room temperature on tensile specimens of 4340 steel in the conditions as normalized and as quenched and tempered to a tensile strength of

273,000 psi, and on a specimen of annealed Invar have revealed (1)

that the practice, commonly employed, of prestraining a specimen

before conducting microplasticity tests introduces appreciable in- stability of the specimen, and (2) the microplastic behavior of the

prestrained specimen, especially at very small strains ranging from

IXIO""^ to IX 10"*, is not representative of that of the specimen in

its initial heat-treated condition.

High-Temperature Creep—An NBS-designed-and-constructed ma- 124
chine has been installed and is being used to facilitate the study of

the mechanisms underlying creep. Controlled through an analog computer, it provides a constant resolved shear-stress loading to single

crystals compensating for slip-plane rotation and reduced cross section. It also has the capability of producing rapid temperature and stress changes and can operate in either high vacuum or inert atmosphere.

Ultrasonic Measurements in Molten Glass—It has been difficult, if not impossible, to perform high-temperature shear ultrasonic relaxation spectroscopy in molten glasses because of the high absorption of

shear waves in the liquid. These structural investigations have been

aided by improved ultrasonic detection using a phase-locking tech- nique. A technique using signal-averaging and synchronized discriminating amplification common to sonar and some light-scattering

experiments was modified for the purpose. This resulted in an increased

range of absorption per wavelength of more than twice that of pre- viously reported equipment. One inexpensive lock-in amplifier and a few general laboratory instruments can be easily incorporated into

all ultrasonic systems with a video output, and will enhance signals

of any R. F. frequency by approximately 25 dB, and increase the

accuracy of amplitude measurements to about 0.1 dB. This added

range enabled the study of shear ultrasonic relaxation spectra in molten glasses, and opened up a new research area : the ultrasonic detec- tion of molecular clusters in immiscible oxide glasses.

Optical, Electrical, and Magnetic Properties

Vacuum Ultraviolet Excited Fluorescence—The fluorescence of

chlorine produced from the vacuum ultraviolet photolysis of phosgene has been observed. From the dependence of the fluorescence upon

the wavelength of the exciting radiation, it has been concluded that

literature values for the electronic energies of two of the upper excited

states of chlorine are too high by as much as one electron volt. It should

be noted in this instance that a well-designed photochemical experiment has yielded results which are of primary concern to the molecular

spectroscopist. It is an excellent example of how different disciplines

interact in an active research area such as photochemistry.

Organic-Dye Lasers—IMR physical chemists have recently insti- tuted a study of the properties of organic-dye lasers. The main emphasis of the program is on studying the mechanism of the laser process

and the role of molecular triplet states in reducing the efficiency of

the system. Theoretical calculations indicate that the addition of

quenching agents specific for triplet states should greatly increase the

efficiency. Experiments are in progress to test the validity of these

calculations. A giant flash-photolysis system has been used to pump

rhodamine 6G, and outputs in excess of IJ and pulse-lengths of 30 to 40 [I s have been obtained.

125
Oftical and EPR Study of Orange Ruby—Orange discoloration

lias been a source of degradation in performance sometimes encountered in ruby lasers. A number of doped sapphire crystals have been

grown and studied in this laboratory. Dopants include Cr (i.e., ruby)

and other single-transition elements, and combinations including Cr

as the second dopant. Optical absorption spectra taken before and

after x-ray coloration show that the discoloration spectra produced

are similar to those reported in laser rods, but only when Cr is present.

Double-doping with Cr plus Mg produces the orange color without

irradiation, and irradiation produces only a slight additional increase.

Valence considerations suggest that the phenomena involve either a change of Cr valency or color centers or both. EPR spectra are being

taken on a number of these samples in an effort to observe and identify

the defects responsible.

Thermo-Optic and Piezo-Optic Properties of Laser Matei^als—

The changes in refractive index caused by temperature and hydrostatic pressure have been determined for five neodymium-doped glasses

and single-crystal ruby by an optical interference method. It is interesting to note that for ruby there is a decrease in refractive index for

both the ordinary and extraordinary ray with applied hydrostatic

pressure. Furthermore, there is an increase in refractive index with

rise in temperature. These changes are not what might be expected on the basis of density considerations. Using the method of uniaxial

loading in conjunction with the application of hydrostatic pressure, the two piezo-optic and two elasto-optic coefficients of each of the five glasses have been determined. The eight piezo-optic and eight elasto- optic coefficients of single-crystal ruby have also been determined.

These data are of immediate interest in laser technology because the

temperature-induced changes in refractive index create a distortion of

the wavefront of light generated in a laser solid. Since the refractive

index is dependent on temperature, there is a direct change caused by

the temperature gradient from the center to the edge of the rod. In

addition, the temperature gradient creates internal stresses which produce further changes in index arising from the stress-optic effect. There are virtually no data in the literature on the temperature and

stress coefficients of the refractive indices of important laser materials.

Plasmaron Structure in the Soft X-Ray Spectrum of Al—As part

of a continuing study of the density of states in metals, the L2, 3 soft

x-ray emission spectrum of Al has been carefully scanned for a lowenergy edge due to a plasmon interacting resonantly with a hole

(called a plasmaron), predicted by recent theoretical studies of the

interacting electron gas. A very weak structure near the predicted

location, but just within the noise level, was seen. An upper limit to the magnitude of such structures was established and it was sug- gested that the light alkali metals should provide a better test of the

theory.

126
Refractive Index of Cuprous Chloride—The refractive index of

single-crystal cuprous chloride (CuCl) was measured at room temperature in the wavelength range 0.42 /xm to 22 /xm. CuCl is a potentially important laser-modulator crystal by virtue of its large electro- optic coefficient. Because it is cubic it lacks the undesirable feature

of natural birefringence present in all commercial modulator materials. In addition, CuCl is transparent to beyond 20 /xm, making

it useful for modulating the intensity of the CO2 laser at 10.6 /xm. The measurements were performed in the wavelength range 0.42 /xm

to 1.2 /xm with a commercial V-block refractometer. The range of

wavelengths was extended to 22 /xm by measuring the wavelengthdependence of interference fringes in thin polished plates. Materials were supplied by the Air Force Cambridge Research Laboratory and

the Massachusetts Institute of Technology.

Infrared Absorption in Perovskites—The optical absorption spec- trum of SrTiOs has been examined over the wavelength range of

2.5 /xm to 25 /xm. Nine broad absorption bands were observed beyond

3 /xm, and a set of sharp lines at 2.86 /xm. The sharp lines are interpreted as due to OH impurities in the crystal, while the broad bands

are believed to be due to multiphonon creation processes, except for one which is a single-phonon process. Selection rules for simultaneous

creation of either two or three phonons were obtained, in dipole approximation, at selected critical points in the Brillouin zone. The

observed bands were assigned, using these rules together with the

experimental phonon-dispersion curves of Cowley and other published

values for the higher-energy branches obtained at specific points in

the zone by other techniques. Some of the phonon energies determined

in this way have not been seen by neutron diffraction techniques. The

results are typical of what is observed in other perovskite-type materials such as LiNbOs, KTaOs, and BaTiOs.

Structural and Spectroscopic Properties of Nichel{II) Pyrazole

Complexes—X-ray diffraction and visible spectroscopic studies have

been carried out on single crystals of some pyrazole complexes of

nickel (II). The electronic-energy levels in two halogen-substituted

complexes were shown to differ markedly from those in the closely re- lated pyridine complexes. Detailed crystal-structure data showed that

the unusual energy-level systems in these complexes were related to internal hydrogen bonding between the coordinated pyrazole molecules and the coordinated halogen atoms. The spectral assignments were based on a reduced effective field of the halogen atom at tlie site of the nickel (II) ion. These assignments were corroborated by the

observed bond distances and pyrazole ring orientations.

Thin-Film Dielectric Measurements—Developments in the commercial manufacture of thin polymer films have generated considerable

interest in the use of these films as electrical insulators. This interest

127
Three-terminal fluid displacement cell used to measure dielectric properties and

average thickness of their films.

has resulted in a joint program between IMR scientists and a research

scientist from FMC Corporation. A three-terminal fluid-displacement

cell was designed and built and is being used to successfully measure

the dielectric properties of commercial films as thin as 0.025 /xm. Not

only does the two-fluid method used with this new cell permit dielectric constant measurements on a 25-jum film with an accuracy of better

than 1 percent, but it also provides a unique way of measuring the

average thickness of these films w^ith an accuracy of the order of 1 percent. This program has resulted in significant advances in measure- ment capability that w^ill be used by industry in the evaluation of

insulating films and by NBS for the development of thin-film reference

standards of dielectric constant and thickness.

Dipole Moments of Molecules in the Vapor Phase—An unconventional method for precise determinations of dipole moments of symmetric top molecules in the vapor phase has been used to obtain data on reactive gases with small dipole moments. The method is based on experimental measurements of the shape of the nonresonant Debye128
type microwave absorption in pure gases and gas mixtures. The

measurements are made by varying the pressure at a single temperature where the gas is chemically and thermodynamically stable. The

errors due to temperature variation are eliminated, and the sensitivity

of the method permits determination of dipole moments too small to be detected by conventional methods.

Loiv-Field Tri-axial Helmholtz Coils—A circular, triaxial, fourthorder, air-core, Helmholtz-coil system was designed and constructed

with the aid of the Navy Bureau of Weapons. The coil system was

designed so as to generate a magnetic field homgeneous to 1 part in

10* over a volume of nearly 100 cm^ This coil system will be used for

the calibration of magnetic flux density measuring equipment, and

in a study of the feasibility of using electron paramagnetic resonance

as a primary standard of magnetic flux density in the range of 0.1 to 30 millitesla. Iron Nuclear Magnetic Resonance in Paramagnetic TiFe and

TiFe-TiCo Alloys—For the first time in any paramagnetic material,

the nuclear magnetic resonance of ^Te has been detected. The dis- covery was made by a team of IMR scientists including an NB8

industrial research associate from the U.S. Steel Corporation. The

team used the combined facilities of U.S. Steel laboratories for sample

preparation and NBS laboratories for the resonance work. Each of

the two samples used, enriched in the stable isotope ^'Fe, is valued at $6,000.

Although the nuclear magnetic resonance is observed with relative ease in ferromagnetic materials due to a signal enhancement related

to the magnetic domains, this observation demonstrates that it is also possible to observe the ^Te nuclear magnetic resonance in paramagnetic materials as well. This resonance is being used to study the

electronic properties of TiFe and TiFe-TiCo alloys. These alloys are

structurally related to TiNi, which has an unusual mechanical memory.

Precision High-Pressure Measurements Via N.Q.R. Spectroscopy—

Pressure measurements up to 2 kbar have been made with a precision

of ±0.5 bar. This has been done using a servo-controlled nuclear

quadrupole resonance spectrometer and a carefully purified sample of

KCIO3. The main source of error at the present time arises from the

small temperature fluctuations (±0.005° C) of the high pressure

vessel. Reactivity and Corrosion

Anisotropic Oxidation of Pyrolytic Gra/phite—Pyrolysis of a hydrocarbon at low pressure and high temperature can be used lo deposit a form of polycrystalline grapliite witli preferred orientation.

As a result of the orientation, with graphite basal ])lane preferentially

129
parallel to the surface of the substrate, anisotropy of physical and

chemical properties is evident. IMR scientists have measured the ratio

of air oxidation of graphite for rates parallel to and perpendicular to the preferred basal plane direction. From 800 to 1800 K, the ratio

increases from about one to seven, with the faster oxidation parallel to the preferred basal plane direction. The offered explanation suggests that the same two-stage mechanism is involved in both directions: chemisorption followed by decomposition of surface oxides.

The surface concentration of available sites is sufficiently different,

however, that in one case the chemisorption is rate-limiting and in

the other decomposition is limiting. This interpretation leads to activation energies in agreement with literature values for both steps of the

mechanism.

Catalytic Decomposition of Hydrazine—Hydrazine and some of its derivatives are of interest as rocket fuels. However, hydrazine decomposes catalytically when stored in some metal containers, such as maraging steel. Investigations by IMR scientists show that the

catalytic decomposition can be reduced to an insignificant rate by

certain coatings electro- deposited on the steel. Among the best for the

purpose are cadmium, silver, electrodeless nickel, and tin-lead alloy.

Stress-Corrosion Cracking of Glass—Glass is usually regarded as an inert material, being highly resistant to chemical corrosion. As a

result it finds use as liners in water heaters, in industrial plants where

chemical resistance is important and in the laboratory. Despite this

well-known resistance, glass is susceptible to stress-corrosion cracking

by water. The effect is so severe that, all other things being equal, the

strength of glass is reduced by about 80 percent in the presence of Avater or water vapor.

Stress-corrosion in glass, as in other materials, results from the slow

growth of surface cracks due to stress and environment. In glass the

phenomena is believed to be due to a chemical reaction between the

glass structure and the water molecules. The rate of reaction can be

monitored by measuring the rate of crack growth as a function of

temperature, applied stress, and environment, and the data obtained can be used to describe the process in fundamental terms used in

reaction-rate theory. During the past few years the Institute for

Materials Research has been conducting such experiments using

fracture-mechanics techniques. Conclusions from such experiments are

as follows

:

1. Crack-velocity data quantitatively satisfies the Charles-Hillig

theory for stress-corrosion of glass.

2. Glasses of different chemical behavior exhibit varying degrees of

resistance to stress-corrosion cracking.

3. In water, the rate of reaction of hydroxyl radicals with the glass

appears to control the rate of crack-growth.

130
4. In gaseous nitrogen containing water vapor, there are three

distinct mechanisms of crack-growth. At low-stress intensity levels the rate of crack-growth is reaction-rate limited. At intermediate

levels, the rate of crack-growth is limited by the rate of water trans- port to the crack tip. At the highest stress-intensity levels, crackgrowth is independent of environment.

Stress-Corrosion Craching of Copper Alloys—In a joint effort at the

IMR laboratories, a research associate from the Research Institute

for Advanced Studies (a division of Martin Marietta) and an IMR

scientist have provided data that supports, in part, a stress-corrosion

cracking theory. The theory proposes that the stress-corrosion cracking of alpha-phase copper alloys in tarnishing amrnoniacal solu- tions proceeds discontinuously by the repeated formation and rupture

of a brittle tarnish film. An important prediction of this "brittle-film"

mechanism is that the cracking rate is determined by the rate of growth

of the tarnish film. Earlier work on the alpha-brasses established that

the cracking rate increases with increasing zinc content of the solid,

with increasing temperature, and with the application of anodic

potentials, but qualitative data w^as not available.

The ellipsometric data from the present study demonstrated quantitatively that the rate of tarnish growth increases significantly with

zinc content, as does cracking rate. For example, the time taken for

the film to attain a thickness of 900 A was found to be 44 min for

pure copper, 16 min for Cu-5 Zn, 317 min for Cu-10 Zn, 1 min for

Cu-20 Zn, and ^ 1 is for Cu-30 Zn. The rate of tarnish growth determined quantitatively was also found to increase with increasing temperature and with applied anodic potentials, as does cracking rate. Pure cooper, which is not susceptible to stress-corrosion cracking in amrnoniacal solutions, was found to have a low (less than alphabrasses) film-growth rate. Further work is needed to explain why

copper does not undergo stress-corrosion cracking in this solution.

Initiation of Pitting of Iron—Studies sponsored by the Office of

Saline Water have shown that before the protective (passive) films on

iron break down in the presence of chloride ions, subtle changes occur

in the optical properties of the films. These changes occur before the

ordinary indications of breakdown (e.g., an increase in current via

galvanometric measurements) signal the onset of pitting. The changes

in film properties, triggered by cliloride ion, have been detected by

ellipsometric spectrometry—a new technique which enables the meas- urement of optical spectra of very thin films on metal surfaces wliile they are immersed in solution. These studies are im])ortant in eluci- dating the mechanism of the pitting of metals, whicli is responsible for

many corrosion failures. Corrosion of Titanimn Alloys—Studies of the initial stages of coi-- rosion in a series of titanium alloys are in progress, using oloctrou

131
An electron transmission micrograph taken from a thin specimen of a titanium- palladium after corrosion in a salt-water solution. A thin film of titanium oxide containing small oxide crystallites is seen superimposed over the microstructure and grain boundaries in the alloy specimen.

microscopy and diffraction techniques. At the same time, quantitative

chemical analysis of microscopic areas is proceeding using an electron

probe micro-analyzer. The influence of high temperatures and pressures, using a salt-water corroding solution, are being investigated.

Extremely thin corrosion films can be studied either in place on the

alloy specimens or after removal to determine the physical and chemical nature of the films. The relative resistance to corrosion of the

various alloys is interpreted in terms of the microstructure and chemical composition of the specimens. The results of these studies should

guide the choice of the most suitable materials for applications to salt-water purification plants.

Microhiological Gorrosidn of Iron—A marine strain of DesulfovibHa has been isolated which produces a mixture of schreibersite

(Ni, Fe)3P, and iron sulfide when grown in a sea water medium con- taining ferrous ions and organic material. Schreibersite and iron

sulfide (trolite) are found to be closely associated in certain meteorites

and tectites. The anaerobic corrosion of iron in the same medium without added

ferrous ions was associated with removal of a protective iron sulfide film formed during growth of the organisms.

Corrosion of Steel Piles in Underground and Seawater Enmronments—The most extensive corrosion test programs ever undertaken

are under way to determine the best means of protecting steel piles

from corrosion. Measurements of corrosion rates are being made

periodically on steel pile specimens exposed underground and in

132
Corrosion rates of steel pilings exposed underground and in seawater are being

studied to determine optimum means of corrosion protection. Polarization tech- niques are used to measure instantaneous corrosion rates of the specimens.

seawater. Polarization techniques developed in the laboratory at NBS

are being applied to monitor the instantaneous-corrosion rates of the

steel pile specimens.

The study is planned to extend over a 15-year period in the seawater

site and 25 years in the underground site. It is expected that the results will show a correlation between the amount of corrosion on the steel

test piles, as determined by polarization measurements, and the actual

corrosion on the specimens which will be measured when the test piles are extracted from the test sites after specific exposures.

In the seawater site, over 100 carbon-steel and low-alloy steel piles

(35 ft long, 45 lb/ft) were installed 19 ft into the Atlantic Ocean

bottom off the coast of Dam Neck, Virginia. Many types of protective

methods are included in the investigation, ranging oyer coating sys- tems (coal-tar epoxy, galvanized, aluminum- and zinc-flame spray,

zinc-rich paints, etc.,) and cathodic protection by zinc and aluminum

sacrificial anodes.

In the underground sites, 21 steel piles (35 ft long, 74 lb/ft) were

driven to bedrock in connection with the construction of a Transcanadian Highway Interchange in Montreal, Quebec, Canada.

Cooperating with NBS in these investigations are the American

Iron and Steel Institute, Province of Quebec, the U.S. Army Coastal

Engineering Kesearch Center, the U.S. Navy Civil Engineering Laboratory, Amphibious Forces, and the Fleet Antiwar Aircraft Trammg

Center. 133
Engineering Materials

Impact Properties of 1^31 Stainless Steel—The inclusion of refrigeration in the heat-treatment of 431 stainless steel has been a common

practice. Data obtained in an investigation of the effects of refrigeration and strain on the notch toughness of 431 indicate that refrigeration

should be avoided in the heat-treatment of 431 parts subjected to stress concentration or impact loading.

Fatigue Oraching in Ohromium Diffusion- Coated Ti-Bearing

Steel—Chromium diffusion coatings on Ti-bearing steel frequently

lead to columnar growth beneath the Cr-rich layer. The grains are preferentially oriented. The depth of the columnar zone does not depend on the chromizing time. A high rate of cooling prevents col- umnar growth. No grain-boundary diffusion or carbide formation at the grain boundaries was observed. The Cr-rich layer is structurally

homogeneous and consists of a-solid solution. The hardness of the

coating does not vary with the chromizing time.

Dimensional Stability of Gage-Block Steels—The causes of dimensional instability in a 52100-type steel hardened to Rc 65 are being

investigated and several important facts are indicated. Precision elec- trical resistance measurements, microhardness measurements, and car- bide determinations indicate that the measured parameters change

Avith long aging-time, and that these changes can be correlated Avith length changes. The results tentatively indicate that three structural processes are occurring : dissolution of carbides, diffusion of carbon to

lattice imperfections, and re-precipitation of carbides at new sites. Properties of Electrodeposited Copper—A comprehensive investigation of the properties of electrodeposited copper, in progress for five years, has beon completed. During the i^ast 3'ear the large amount of

data has been compiled into numerous tables and graphs and the complete work prepared for publication.

Tlie project was sponsored jointly by the American Electroplaters'

Society, the International Copper Research Association, the Copper

Development Association, and the National Bureau of Standards. Investigations covered the types of plating baths used in industry : acid

sulfate, cyanide, pyrophosphate, fluoborate, and amine baths. A number of properties were measured on each type of deposit obtained under

about 150 different sets of operating conditions, the latter comprising

variations in bath composition, temperature, and current-density.

Properties measured and correlated included : tensile and yield

strengths, modulus of elasticity, elongation, internal stress, fatigue

limits, hardness, densit}^, electrical resistivity, thermal expansivity,

structure, and cliemical composition. Effects of cold-working and

annealing, and effects of cryogenic and elevated temperatures on some

of the above properties, were also determined.

134
Development of a Radiopaque Composite Dental Restorative Material—Radiopaque esthetic direct filling materials are needed to

facilitate dental radiographic diagnosis. An x-ray-opaque composite

restorative material was developed having adequate esthetic properties

for use in anterior teeth. The resin binder is a ternary eutectic dimethacrylate foraiulation. The powder consists of a BaFs- containing glass

and fused silica both treated with a silane coupling agent and con- taining peroxide initiators. One hundred and ten restorations were placed using this newly developed material. The restorations will be observed over a prolonged

period. They had sufficient radiopacity and yet were esthetically

pleasing.

Spherical Alloy for Dental Amalgam—A significant improvement

in the physical properties of silver-tin-mercury alloys used in restorative dentistry has resulted as a culmination of research conducted at NBS. In this study, irregularly shaped particles formerly used to prepare dental amalgam alloys have been replaced by spherical alloy

particles with a consequent improvement in strength and durability.

In addition, the alloys can be packed into the tooth cavity with less pressure, resulting in greater comfort and convenience for both the

dentist and his patient. The new alloy has recently been marketed both

in this country and abroad.

PhotomicrogTai)li of dental amalgam alloy prepared with splicric-il alloy iclcs. 135
Gallium Alloys for Restorative Dentistry—A gallium-tin-palladium alloy has been developed which may be substituted in place of

the mercury-tin-silver alloys now used to replace tooth structures

lost as a result of caries. The new alloy is 50 percent stronger, several

times more resistant to flow under an applied load, and has a thermal

expansion coefficient closer to that of human teeth than the present

dental amalgam alloys. In addition, this alloy wets tooth structure and thereby produces a more effective seal against fluid infiltration at the margins between the filling and the tooth. The alloy requires

extensive biological and clinical testing before it can be made available for extensive use. Creep of Pure-Gum Vulcanizates of Natural Ruhher—The creep

of vulcanizates of natural rubber cured with varying amounts of

dicumyl peroxide was compared with that of vulcanizates cured by

typical conventional sulfur-accelerator systems. The measurements

involved indentation of a flat rubber disk as a function of time t and

temperature T. The product of shear compliance / and 7" as a function of log t was represented by a family of curves with T as the parameter. For the vulcanizates cured with the sulfur-accelerator system,

previous work has shown that the individual curves could be shifted

along the abscissa to yield a single continuous curve with a slope which

increased from a negligible value to a maximum and then decreased,

continuing through a region of minimum slope extending over about 7 decades of time before ending in a region of increasing slope. The

value of the creep was 1.5-2.0 percent per decade in the region of

minimum slope. When the same procedures were applied to the vulcanizates cured with dicumyl peroxide, the individual curves oi JT

against log t at each temperature did not yield a single continuous curve when shifted. In a limited region just above the glass transition temperature, the creep was appreciable, but neither a constant- activation-energy shift nor a Williams-Landel-Ferry shift was satis- factory. Above this region it was clearly impossible to obtain a

single curve, since the compliance-temperature product at a given

time increased with increasing temperature while the corresponding

creep of the dicumyl peroxide vulcanizates was generally too small

(<0.5% per decade) to be measured between 5 s and 600 s, except

when the compound contained less than 2.5 parts of effective dicumyl

peroxide. Outside of these regions the shear modulus was found to increase linearly with temperature. The investigation included temperatures as high as 100 °C and effective dicumyl peroxide concentrations as high as 25 parts per hundred of rubber.

TECHNICAL ASSISTANCE TO OTHERS

IME gives technical assistance and advice on materials to other

Government agencies, and to science and industry. Arranging con- 136
ferences and seminars to facilitate dissemination of new data useful

in solving materials problems is also an important service provided.

Advisory and Consulting Services

Life of Postage-Stamp Printing Plates Increased—Although prior

recommendations of NBS have resulted in improved life of postagestamp plates used by the Bureau of Engraving and Printing, a breakthrough in this area has been made. By judicious shot-peening of

selected portions of the back of the plates, fatigue-resisting compressive stresses have been introduced and machining irregularities

removed. The results on lifetime has been to increase service-life by

more than an order of magnitude. One test plate now in service has

registered 1,700,000 impressions and is still serviceable. This contrasts with untreated plates which may fail at less than 100,000 impressions.

Carhon Dioxide Standards—IMK chemists have developed a highly

accurate gravimetric technique to j^repare three standards of carbon

dioxide in air for the Environmental Science Services Administration.

The compositions were ascertained to within one part in ten thousand,

and the mixtures will serve ESSA as primary standards for the

continuing investigation of atmospheric composition.

Galitration Standards for Salinoineters—The conductivities of 20

samples of sea water of varying salinities were measured for the Department of the Navy. These samples will be used for the calibration

of oceanographic salinometers. The same techniques were also used

to measure the conductivities of two different lots of Standard Sea

Water with an accuracy of 50 ppm. Standard Sea Water is a con- venient and widely accepted reference for oceanographic measurements

but is available at only one value of salinity.

Conferences and Symposia

Syrrhfosiwm on the Structural Properties of Hydroxyapatite and

Related Compounds—Sponsored jointly with the Office of Na\'al Research, in cooperation with the American Dental Association and the

Georgia Insitute of Technology, this symposium reviewed critically

the information available on apatites. The properties of these com- pounds have importance in diverse areas such as tooth, bone and

pathological mineralizations, minerals, fluorescent coatings, water

purification, and oceanography. Twenty papers were presented and

125 visitors participated in the symposium. Tlie papers are to be

published as a text. Symposium on the Tliermodynamic Properties of Bulk Polymers—

Through its Polymers Division, the Institute for Materials Research

sponsored this symposium at the NBS Gaithersburg Laboratories on 137
March 10-12, 1969. The symposium assembled over a hmiclred polymer

scientists from industrial, university, institutional and govermnental

laboratories to focus discussion on the specific aspects of polymer

science indicated by the symposium title. Thirty papers were discussed on subjects including: crystalline, vitreous, and elastomeric physical

states ; crystallization, melting, glass transformation, and other physical transitions and relaxations; elasticity of elastomers; special

methods for determining thermodynamic properties ; state properties

and their derivatives for common and special situations; and the

relationship between thermodynamic and molecular properties.

Symposium on Ion-Selective Electrodes—This symposium, held at NBS on January 30-31, 1969, was attended by approximately 450

physical and biomedical scientists. The present state of the art and

future capabilities of these electrochemical sensors were evaluated. A

broad spectrum of topics rangmg from principles, characteristics and

basic chemical studies to aj^plications in biomedicine and industrial

analysis and control was reviewed. The published proceedings of this

symposium, consisting of the complete texts of the invited review

papers plus selected segments of the panel discussions, is available

from the Government Printing Office as NBS Special Publication

314

Modem Trends in Activation Analysis—The Third International

Conference on Modern Trends ui Activation Analysis, sponsored

jointly by the National Bureau of Standards, the U.S. Atomic Energy

Commission, the International Atomic Energy Agency, and EUEI

STOP, European Communities Commission, was held October 7-11,

1968. The Conference was attended by over 400 scientists, including

100 from countries other than the United States. Each da}' a plenary

lecture, given by a recognized world authority, outlined the state-of- the-art for the various phases of activation analysis. This lecture was

followed by simultaneous sessions with contributed papers. A panel

discussion at the end of each day's sessions provided a s^aiopsis of

the major points of discussion in each session, allowing attendees to

liear the higlilights of sessions the}^ were unable to attend. More than

150 technical papers were presented. The published Proceedings of the

Conference are now available.

Conference on Fwndamental Aspects of Dislocation Theory—Held

at NBS under the auspices of IMR on April 21-25, 1969, this confer- ence was devoted to a thorough appraisal of dislocations in crystals.

One hundred theorists from 18 different countries attended to center on the questions : "How far have we come ?*' and ''Where do we go from

here?" Seventy papers were presented, ranging over all aspects of the

subject including its applications to mechanical properties of materials,

lattice mechanics of defected crystals, biophysical applications to proteins, and liquid crystals. The published proceedings are expected to be

available in the spring of 1970.

138
Symposium on'"'' Nuclear Standards for Chemistry and Technology—

This Symposium was held September 8-9, 1968, sponsored jointly by

the American Chemcial Society's Division of Nuclear Chemistry and

Technology and the ACS Committee on Standardization Relations.

The Symposium was organized to bring workers in the diverse areas

of safety, health, quality assurance, and specific engineering standards together to discuss present programs and future needs in the

relatively new and rapidly growing field of nuclear technology. The

published proceedings of the Symposium are available as NBS Special Publication 310. '•^Symposium on an International Standard Reference Materials Program^^—This Symposium was held May 26-28, 1969, at the National

Bureau of Standards, under the joint sponsorship of NBS and the

International Committee on Weights and Measures (CIPM). Thirtythree representatives from 15 countries and 4 international agencies

attended. The goal of this first International Standard Reference

Materials Symposium was to explore the possibilities and problems

of an international SRM Program. A summary of the Symposium dis- cussions is being published in Metrologia.

375-572!—70' 10 139

INSTITUTE FOR APPLIED TECHNOLOGY

The Institute for Applied Technology (lAT) attempts to meet the

Nation's need for measurements and standards related to the artifacts

of our society. Thus, the lAT programs are concerned with technological or "engineering" measurements and standards which deal with

products, commodities, devices, processes or systems. These measure- ments and standards are the language of the market place for coupling

user requirements with the performance capabilities of products, processes or devices, and thus bring order and quantification to man's

use of his technical skills. The Institute provides a technical base for the development of en- gineering and product standards, and measurement methodology. Its programs are oriented to industiy, to the States and regions of the

country, and to all levels of Government. They bridge the interface

between science and its applications, and by coupling science and tech- nology with the daily activities of commerce, industry, and Government, they stimulate economic progress. The Institute is responsible for several mandatory legislative assign- ments. Among them are the Flammable Fabrics Act as amended in 1967, the Fire Kesearch and Safety Act of 1968, and the Fair Packaging and Labeling Act. lAT activities fall into two major categories: Technological Measurements and Standards, and Technical Innovation. A substantial

part of the work done in the lAT program is technical assistance to other parts of the Bureau, other Government agencies, and to industry.

Work done in motor vehicle safety research and technical analysis is virtually all done in support of the mission of other agencies of Government. In other fields, a lesser but still substantial vohime of lAT

work is done at the request of others. TECHNOLOGICAL MEASUREMENTS AND STANDARDS

This category covers the Institute effort for the broader extension

of the national measurement system into the engineering and technological fields. It is a program to apply principles of good measurement,

rather w^ell defined in the science area, to the determination of per- formance or other significant characteristics of products systems and

141
devices important either in Commerce or to Government needs. In

essence, the objective is to find ways by which standards or a national

and sometimes international consensus of measurement methodology

can be develo^Ded for items, systems, and devices which are not readily

evaluated in terms of existing measurement methods.

The performance concept introduces man into the measurements

and standards process, and the whole idea centers on the belief that

products, processes, services, and systems can be described and their

performance can be measured in terms of user's requirements without

regard to their physical characteristics, design, or method of their

creation. Key to this method is the identification of measureable per- formance criteria for meeting the user's requirements, thereby cou- pling subjectively derived needs with objective technical measure- ment methods.

As the complexity and teclmical sophistication of articles of commerce increase, it becomes increasingly difficult to define those characteristics of a product which best measure its performance. The virtue

of the performance concept in measurement and standard development is that it stresses the end to be attained, and leaves the means to obtain the desired end w^ide open.

Today many complex products are actually complete "systems,"

and the only feasible way to evaluate them is in terms of their per- formance against criteria established to meet the user's require- ments. The concept encourages innovation when producers can meet

the performance required by whatever design of product will do the

job.

The idea of performance criteria also has ramifications beyond

those concerned with articles of commerce. Our national welfare depends critically on making informed decisions related to complex

social and economic policies and programs. To do this, one needs to define criteria of performance for these policies and programs and

be able to measure or predict possible benefits and costs of alternative

actions. Through the techniques of system analysis and operations

research, technology has provided a means for helping such decisionmaking.

Institute activities in technological measurements and standards

range from the development of performance criteria and test methods

for individual items to the study and analysis of complex systems

such as a multi- State transportation network.

During the past year several organizational changes were made

to concentrate the Institute efforts in the technology area. The Center

for Computer Sciences and the Clearinghouse for Scientific and

Technical Information were separated from lAT. In addition, a j)rod- uct testing laboratory developed for the General Services Administration (GSA) was transferred to GSA. Added to the Institute were a 142
Measurement Engineering group and an Instrument Shops group.

The Institute inaugurated an Office of Fire Eesearch and Safety with

responsibility for planning the programs anticipated when funds be- come available under the terms of the Fire Research and Safety Act

of 1968. Program elements include:

Technological Measurements and Standards

Building Technology

Electronic Technology

Systems Analysis

Motor Vehicle Safety

Engineering Materials

Industrial and Consumer Products

Technological Innovation and Diffusion

Invention and Innovation

Building Technology

The spiraling of construction costs combined with the tremendous

backlog of housing units required to be produced in the next 30 years

have accelerated the move to the industrialization of the building

process. This change, from an industry heavily dependent on hand

craftsmen techniques, to one of mass-production is generating pres- sures for up-dated standards, improved techniques for determining

user requirements, and advanced capability for evaluating the per- formance of complex components. In order to meet this demand, the

NBS programs for building technology have been broadened to cover more than the traditional materials research, which alone is no longer

adequate to provide answers for the new questions raised by industrialization of the building process. All of these questions involve a consideration of cost to some extent. Therefore, this broadened scope

must include studies of building economics. The program of economic

studies has been initiated as a multiagency project, designed to develop

a computerized construction cost control system that relates unit building prices, operation, and maintenance costs. This information can be

used to project estimates of both building and operating costs from

preliminary planning, through construction, to ultimate building use. The scope of research in building technology in the past year was

expanded by the creation of a "Sensory Environment Branch" with

three sections, namely; Environmental Engineering, Psychophysics,

and Building Transport Systems Section. The environmental engineering program will continue tlie work which has been going on

with regard to the materials and equipment wliicli create the favorable interior environment of buildings. The psyclio[)liysics program

will study techniques for evaluation and measurement of the responses

of building occupants to the visual, aural, thermal, and spatial char143
acteristics of the interior environment. The transport systems program

will gradually be enlarged from plumbing activity to include elec- trical and communications systems, and food, water and fuel distribii- tion, and movement of people. A "Mobile Acoustical Laboratory"

has been acquired. This laboratory can be used at the site of existing

structures. The application of advances in building technology depends on

dissemination of new information as it is developed. NBS has hosted

or sponsored conferences, seminars, and symposia held throughout the

year to this end; such as: Man and His Shelter—Roofing Technology—Durability of Insulating Glass—Wind Loads. ... It is anticipated that there will be larger numbers of such conferences in the

future.

A new program in urban technology has been initiated to develop an information framework of user needs for housing, especially for

low-income housing. The questions to be examined include what information is germane, how it may be manipulated, where it falls in

relation to other information, when it is applicable, and to whom it pertains. Criteria for user needs are derived from all sources in dividing

the fields of sociology, physiology, and psychology. Where criteria

cannot be developed from these sources, the program will develop

substitute evaluative techniques and a basis for judgment decisions.

The building technology program continued the traditional laboratory and field support provided to Federal agencies, State, and local Government groups concerned with building construction and tech- nology. Technical consultation and advice was made available to in- dustry, and the staff continued to work closely with the many private

standards-making groups throughout the country.

Outdoor Exposure of Building Materials—The Building Research

Division completed the establishment of six outdoor sites for testing

of building materials. These sites were selected to provide diverse

weather conditions and are located at the following facilities

:

NBS, Gaithersburg, Maryland

Fort Holabird, Baltimore, Maryland

U.S. Naval Station, Roosevelt Roads, Puerto Rico

Nellis Air Force Base, Las Vegas, Nevada

Fort Lewis, Tacoma, Washington

Fort Greely, Fairbanks, Alaska

Permanent racks for holding specimens are now in place and materials

are being exposed at all sites. Many studies are underway to evaluate the effects of these various

climates on materials. Some of the current studies are concerned with

(1) weathering characteristics of aluminized steel and roofing, (2) the

spalling resistance of porcelain enamels, (3) the color stability of

plastics, and (4) the durability of paints.

144
A program will be implemented to obtain or measure the exposure

parameters at the sites. Static sampling devices from the Public Health

Service, designated as "Effects Packages", have been placed at the

NBS (Gaithersburg) and Ft. Holabird (Baltimore) sites. These devices indicate air quality and in conjunction with weather data will

help establish the relative severityo f exposure conditions at each site. Wind Effects on Buildings—The effects of wind on buildings is the

subject of a study jointly sponsored by the Environmental Science

Services Administration and NBS. This problem has assumed great

importance with the recent trend toward lighter more slender buildings and larger window panels. U.S. Weather Bureau records indicate

the average yearly damage to structures by wind in the continental

United States is approximately $600 million with two years on record

for which the damage exceeded one billion dollars. The study will ulti- mately result in improved design techniques for structures exposed to wind. Most building codes make some provision for wind loads but are largely based upon results of wind-tunnel studies in which prototype

conditions were incorrectly modeled. A number of pressure sensors have been installed in the Building Eesearch Building at the NBS

site to measure both steady and fluctuating pressures over the exterior

walls. Simultaneous recordings of the oncoming wind are obtained

by means of fast-response anemometers on an array of six towers

placed upwind of the building. Once the techniques associated with in- strumentation, data acquisition, and data reduction are perfected, the

study will focus on taller buildings where the response of the structural

frame to aerodynamic forces is of primary concern. Strength of Inserts Embedded in Reinforced Concrete Slabs—As

the cost of construction continues to increase, more and more designers

are looking for methods to optimize floor space utilization. One method

commonly used is to suspend from the ceiling equipment which might

otherwise be occupying premium floor space. An increasing number

of devices suitable for suspending such loads are being used in industrial, institutional and commercial buildings.

One such device being used with reinforced concrete slab construction is an anchor commonly called a concrete insert. These concrete

inserts are made to receive either an ordinary threaded rod or the

head of a machine bolt. They are simply fastened to the formwork prior

to placing the concrete. This simplicity offers advantages over other

devices such as embedded anchor bolts which must penetrate the nor- mally reusable formwork.

As far as is known, no systematic study of the factors which affect the load-carrying capacity of inserts in reinforced concrete slabs has

been published. It is known that some manufacturers have investigated

certain variables, but the scope and the results of the tests are not

known. Ordinarily, the manufacturer's catalogs are the only source

of data regarding the load-carrying capacity of most of these inserts. 145
To save floor space, equipment is often suspended from inserts embedded in concrete ceilings. A systematic study was made of the factors affecting the strength of these inserts. Here, an insert has been tested to failure in a sus- tained load test. Because of the limited availability of concrete insert data the Building Research Division, in cooperation with the Post Office Department,

conducted a comprehensve study of the variables influencing the ulti- mate load carrying capacity of some commonly used inserts. In the test, the effect of cyclic fatigue on the pull-out strength of

the inserts was being investigated.

In a report recently issued, design criteria for the inserts were rec- ommended. These criteria take into consideration 10 variables com- monly encountered in construction.

Study of Occupancy Loads in Postal Facilities—The Post Office Department is faced with the problem of moving an ever increasingvolume of mail efficiently and rapidly from pickup to delivery. To

cope with the problem, efforts are being directed toward mechanizing

the mail handling and processing operations. This equipment accounts

for ia large portion of the occupancy load that is imposed on Post

Office structures. It is expected that the loads on these facilities will

increase as more and more automatic mail processing equipment is developed and installed in the buildings. Present data is inadequate

for design of post office structures for the expected loadings over the

useful life of the building. Consequently, the present design procedure

must, of necessity, include exceedingly conservative values for

loadings.

146
The Building Eesearcli Division has undertaken a project to study

the existing loads in a sample of postal mail handling facilities across the nation. The main objective is to investigate the magnitudes and

distributions of actual occupancy loads imposed on the structures for

the purpose of making engineering recommendations for values of

loads to be used in the design of new facilities. The work has been in progress for approximately one year and was

carried out in two phases. The initial phase of the work was to develop

background information on mail handling operations, process machinery, and facility layouts, and to formulate the most suitable measure- ment techniques and evaluative methods for conducting the study. At

the same time, load sensing devices and data acquisition instrumentation for field measurements were designed and developed in the

laboratory.

The next phase of the work was concerned with the field survey of

actual loads in specific structures selected as a representative sample of

Post Office mail handling facilities across the nation. Computer pro- grams are being developed for automatic data processing and evaluation. Three facilities, located at Greensboro, N.C., Chicago, 111., and

Buffalo, N.Y., have been surveyed thus far with plans to survey at

least six more over the next year. Measuring the Smohe Generating Characteristics of Materials—

The smoke density chamber, designed and developed at the Bureau, was put into commercial production following comparative testing

and preparation of a formal proposal of method. The illustration

shows the first commercially produced model. There are nine chambers

in existence and 16 under delivery to testing laboratories and private

corporations.

The smoke density chamber method measures the smoke generating

characteristics of solid materials by monitoring the attenuation of a

light beam by the suspended particulate matter generated from materials under both pyrolytic decomposition (smoldering) and flaming

combustion within a closed chamber. The resulting measurement is expressed in terms of maximum specific optical density and the time

to generate a specified fraction of the maximum specific optical density.

Developmental testing with the smoke density chamber resulted in

several design and technique improvements. These included: (1) a multihole burner for better flame anchoring and uniform distribution

during flaming exposures, (2) techniques for supporting thermoplastic materials, and (3) a procedure for evaluating the influence of

delamination, cracking, peeling or other separations on the smokegenerating characteristics of laminated or faced composite materials.

National Conference of States on Building Codes and Standards—

In fiscal year 1969, continued staff support Avas given to a number of

States in organizing a National Conference of States on Building

147
The smoke-generating characteristics of materials are studied in this smoke

density chamber, which measures the attenuation of light resulting from the smoke generated by smoldering or flaming materials. Codes and Standards. Modeled after the National Conference on Weights and Measures, the objective is to obtain more uniform building standards among the States. Since a majority of the States do not

have research facilities, the National Bureau of Standards building

technology program findings will serve in support of the States in the

National Conference.

The second annual meeting of this group was held in April 1969,

attended by representatives from 36 states, the District of Columbia

and Puerto Rico. Eevised procedures and by-laws were adopted, standing committees established, and the Conference unanimously approved

the goal of achieving a greater degree of intrastate and interstate

uniformity within and among the states in matters of building code

requirements and standards.

Floor-Surface Resistance to Movements of Wheeled Vehicles—The

Public Health Service has been faced with an increasing demand for

148
use of different floor coverings, such as carpeting, in hospital and

other health care facilities. The National Bureau of Standards developed a testing procedure to measure starting and rolling friction

of wheeled vehicles on various floor surfaces. A hospital bed was se- lected as the test vehicle to be used in the study as it is the most prevalent piece of portable equipment in the hospital. Instrumentation was

devised to measui'e the forces required to initiate motion as well as to measure the forces required to maintain motion of the bed. Forces were measured with the bed empty and with an applied live load of

300 pounds. Nine different floor coverings were tested while the test bed was equipped with casters designated by the manufacturer as "hard" and ''soft.'" Results show that soft coverings may offer almost

five times as much resistance to movement as does resilient floor covering.

Performance Tests of a Prefahncated Building—The structural and

thermal performance of a prototype pi^efabricated building system was determined for the U.S. Navy. The building system is being developed for use as an advanced-base, relocatable structure. The building was made of modular sandwich panels. Floor, wall and roof panels

Part of the equipment used in structiir;il tcst.s df ;i prcriilnicated buildhii,^, one

wall of which is seen at the far right.

149
consisted of interior and exterior pJuminnm skins bonded to a kraft

paper-honeycomb core. The test building was prefabricated in Florida,

trucked to NBS, and erected for test in the large Building Eesearch

Division environmental test chamber.

Structural tests to simulate wind loads and snow loads were made.

Air leakage at the windows and doors and at the joints of the pre- fabricated elements was measured with a small inside pressure and

revealed by smoke tests. Heat loss and condensation observations were

also made.

As a result of the performance tests a nmnber of desig-n changes were recommended to improve the thermal and structural performance

in the furthei' development of this building system.

Field Studies of Air-Gleaning Systems in Post Offices—In cooperation with the Post Office Department, the Bureau's Building Research

Division made measurements of the diurnal and seasonal variations of

the airborne particulates in postal work spaces under operating conditions. The purpose of this work was to determine the performance

of different types of filters and air-cleaning systems in use to help

prescribe the most economical and effective ways for cleaning air. Airborne dirt is not only important for health and housekeeping reasons, but it is also a possible cause of failure in mail-handling and processing

macliines. The field measurements involved application of techniques

used for air pollution studies as well as several new techniques developed specifically for building spaces and ventilating systems.

Electronic Technology

The electronics industry is one of the fastest growing and most

heavily research-oriented in this country. In the context of R&D funds

spent by the industry, NBS activities are relatively small, but the

Bureau's influence is broad. Devices are being developed faster than

adequate measurement methods for the control of the fabrication

processes and for the characterization of the finished devices. The

Bureau's contribution to the fields lies in this critical area. Its pro- gram emphasizes the development of improved basic measurement

methods of significance to advances in the entire technology.

Since the Government purchases more than half of the industry out- put, the Bureau's work is of interest to many Federal agencies. The

Bureau has undertaken joint programs on methods of measurement

for semiconductor materials, process control, electronic devices and

transducers. The objectives of these programs are enhancement of the

performance, interchangeability, and reliability of discrete semiconductor devices, integrated circuits, and transducers and improvement

of their use through better methods of measurement specifying materials and devices and in control of device fabrication processes. The

150
goal is to provide a set of measurement methods which have been care- fully evaluated for technical adequacy, which are acceptable to both

users and supiDliers, and which can provide a common basis for the

purchase specifications of government agencies. At the end of the fiscal year investigations were underway in a large number of measure- ment areas in addition to activities related to teclmical and information services,

Inliomogeneities—Variations in the resistivity of a silicon wafer

can cause significant variations in device characteristics. In large

scale integrated circuits and large area power devices these variations

result in nonuniform current distributions which may be unnoticed

until they cause device failure. Although it is possible to measure

resistivity variations by means of a point-to-point measurement with

conventional four-probe or spreading resistance techniques, a scanning

technique is more suitable in many applications because it does not

require the placement of probes on the region of interest. A study

of photovoltaic method for measuring resistivity variations shows

that this technique gives qualitative resistivity profiles on circular

silicon wafers. Recent efforts have been directed toward the establishment of an analytical expression to relate the photovoltage measured on the diameter of a circular wafer to the resistivity gradient. The

studies of various surface preparations have also led to the selection

of a technique which reliably and consistently reduces the adverse

effect of surface recombination in p-type silicon wafers.

Deejy-Lying Trapping Levels in Indium Antimonide—Semiconducting compounds of the III-Y type, such as indium antimonide, contain

naturally occurring trapping centers located near the middle of the

forbidden energy gap. These centers control the electrical properties

of high-purity specimens from which most of the shallow doping

impurities have been removed. Although observed in all reported

specimens of high-purity indium antimonide, the origin of these

centers remained uncertain. From results of ISTBS experiments in

which electrical resistivity, Hall coefficient, and majority and minority

carrier lifetimes in high-purity indium antimonide specimens were measured before and after the addition of lithium, the donor-like

nature of the center was confirmed ; a simple lattice vacancy, probably an indium vacancy, appears to be responsible for the trapping center. The trapping centers are apparently frozen in at a concentration of

approximately 10^^ cm'^ during crystal growth. Growth of crystals at lower temperatures, as, for example, by vapor deposition, would be

expected to result in a lower concentration of vacancies.

Wire-hond evaluation—A dominant cause of device failures in both

radiation and nonracliation environments is failure of the wire bond

used in connecting the semiconductor chip to the external leads. Most

wire bonds are of good quality and do not fail. The problem is the

151
early identification of those which will eventually fail in use. Survey

and evaluation of methods used for determining strength of w^ire bond

systems in semiconductor devices have been undertaken. A comprehensive study of existing procedures and techniques is nearing completion and a critical review of the present status of wire bond testingis being prepared. Systematic studies of factors which influence wire

bond quality have been initiated in order to identify those parameters

for which tests must be standardized. An improved method of grasping

wire has been developed for use in pull tests which are commonly

employed to determine the strength of the wire bond.

Radiation Damage in Silicon Nuclear Detectors—Silicon nuclear

radiation detectors operating on earth-orbiting satellites and deep

space probes can be destroyed by high fluxes of low-energy protons

and electrons which exist in the trapped-radiation belts or which arise

from transient solar events. In cooperation with the NASA-Goddard

Space Flight Center, the Bureau's Electronic Teclinology Division

has been studying radiation damage effects in silicon surface-barrier

transmission detectors so that the useful lifetime of such satellite- borne detectors can be predicted. Effects of damage by protons with

energies between 50 keV and 5.0 MeV have been studied; damage

from electrons with energies between 100 keV and 2.0 MeV is cur- rently being investigated. The study has shown that general guidelines

for reducing the effects of damage by low-energy charged particles

include (1) the operation of detectors at the highest fields possible,

and (2) a reduction of the density of defects produced by radiation

in the high fi.eld or barrier region of the detector. With respect to the

latter point, the useful lifetime of silicon transmission detectors operating in the presence of low-energy protons was found to be extended

several orders of magnitude when the detector was mounted so that

the rear, ohmic contact was irradiated rather than the front, surfacebarrier contact. Thermal Management—Power dissipation in a semiconductor device

is limited by the maximum permissible temperature of the semiconductor junction. To assist users in determining junction temperature

under actual operating conditions, semiconductor manufacturers spec- ify the thermal resistance and in some cases the transient thermal

response of the device. These are determined indirectly by means of

electrical measurements, or calculated from heat transfer considerations. In either case, accuracy and reproducibility are poor, and adequate correlation between calculated and measured values and betw^een

values obtained by different methods of measurement is lacking.

Much of this difficulty results from the fact that the current distribution is usually not uniform over the area of the junction, causing

localized variations in junction temperature and further discrepancy

between the predicted junction temperature and the actual value at 152
the highest, and therefore most critical, local temperature. The seri- ousness of this problem has been repeatedly emphasized by suppliers

and users of semiconductor devices, individually and through the

Electronic Industries Association.

In response to these needs, a critical review of thermal resistance

and thermal response measurements in diodes and transistors has been

undertaken. The validity and reproducibility of existing methods of

determining thermal resistance is being studied in the laboratory.

Thermographic phosphors are being used to determine the relationship

between the junction temperature predicted by the methods and the

actual junction temperature in the device. A study to determine the

feasibility of using temperature-sensitive phosphors to measure the

temperature distribution on the surface of a transistor chip has been

completed and equipment assembled to facilitate the use of such phosphors for this purpose. Better understanding of the thermal per- formance of semiconductor devices will permit better prediction of

their power-handling capabilities under both continuous and pulse

operation and will enhance elTorts to detect anomalies by screening

for abnormal heat dissipation.

Gharacterization of Germanium for Nuclear Radiation Detectors—

A comprehensive program for measurement of the characterization

of materials and quality of gamma-ray detectors fabricated from tesc specimens of germanium submitted for analysis is being carried out in cooperation with the Atomic Energy Commission.

Presently 68 germanium crystals contributed by various domestic

and foreign suppliers, and U.S. and Canadian national laboratories

and universities are being evaluated. The correlation of three methods

for determining oxygen in germanium—infrared absorption, lithium

precipitation and lithium mobility—is being studied. Lithium ion

drift-mobility in germanium has been measured between 2i and 61 °C,

the temperature range normally encountered in the fabrication of

lithium-drifted germanium gamma-ray detectors. The values meas- ured were higher than those previously obtained by extrapolation

from data obtained above 150 °C. Based on these studies, a method

for evaluating germanium crystals by determining the mobility of

lithium has been developed for the American Society for Testing and

Materials Committee F-1.

Piezoelectric Response of Polymers—Piezoelectric materials are used in a wide range of applications to generate and to measure motion,

pressure, and flow. In many cases their applicability or tlieir efiicieiicy

is limited because presently used piezoelectric materials are hard, still', dense, and brittle. Polymers provide a choice of mechanical properties

ranging from those of light, soft, foam rubber to some approaching

those of crystalline materials. However, the ])iez()electric i'esi)onse of

available polymers, when it exists, is too small for ])ra(*tical a])i)li('a- 153
tions. NBS investigation shows that proper treatment with heat and

intense electric fields conld develop a piezoelectric response in some

inactive polymers and significantly increase the response in polymers

having slight activity. The resnlts of the investigation suggest that

improved methods of treatment could develop sufficient piezoelectric

response in polymers for technological and industrial applications.

Systems Analysis

In any program for promoting the application of technology to complex problems of industry or Government, the use of systems analysis or operations research is almost a mandatory requirement. The NBS

Technical Analysis Division (TAD) seeks to develop, test, and dis- seminate systems analysis techniques which are applicable to public

sector problems in terms of program planning, resource allocation,

and program execution.

The lAT systems analysis group is the largest such organization

within the civilian agencies of the Government. It serves other agencies

in the solution of their specific systems analysis problems, and helps

these agencies to develop their own capacity to tackle complex systems

problems. It also conducts research on the cost-benefit analyses for

Government programs.

During FY 1969 the IAT systems analysis group started a modest re- search efi^ort in standard definitions for the concepts and elements

used in the economic evaluation of Government programs, particularly

in the area of applied science projects. Methods were proposed for

measuring the economic value of Government services to individual

citizens in contrast to services for business or public agencies.

Post Office Department Mechanization Projects—A systems engineering project is currently being conducted to develop specifications

for mail-handling systems. These specifications may be used by the

Post Office Department Bureau of Research and Engineering as a guide

in developing more efficient and effective hardware.

A parallel study identifies and quantifies the relationships between

physical characteristics of letter-sized mail and mechanical mail processing. This study will define the limits of mechanical processing.

A research program at the Human Factors Laboratory of the Bureau

of Research and Engineering is directed and staffed by NBS personnel from TAD's Behavorial Sciences Group. Research projects in- clude identification of the man-machine aspects of postal mechanization. Recent studies have included evaluation of closed circuit televi- sion as a means of viewing the addresses on letter-sized mail ; examination of the relationship of the number of digits in a numeric code to the processing time for a piece of mail ; and a comparison of machine

pacing and self-pacing in the operation of two configurations on numeric keyboards.

154
Maritime Consolidation Centers—In response to the U.S. Maritime

Administration, the Bureau investigated the advantages of strategically locating centers where goods for export and import could be consolidated and loaded in containers. Such centers would be established

at intermediate points between importers or exporters of commodities.

Cargo would accrue until a full container could be shipped.

The Division analysts have developed a model for evaluating the

costs and benefits which the shipping industry would derive from the

establishment of such centers. It was found that the specific location of

points where goods could accumulate and be containerized would be

of definite advantage to the shipping industry and the U.S. Merchant

Marine.

Progress in Transportation Simulation Studies—The Northeast

Corridor Transportation Project sponsored by the Department of

Transportation has advanced to an operational stage in which the

complex of models has been used to evaluate a set of alternative trans- portation systems for the Northeast Corridor. A variety of new trans- portation technologies—high-speed rail, tracked air cushion vehicles,

vertical takeoff aircraft and the like—have been examined usiup; the

models. The result of the simulation tests are undergoing review and

will be used to make suggestions as to choosing among possible Federal

government policies with regard to the development and implementation of intercity transportation facilities. The Department of Housing and Urban Development asked the

NBS Technical Analysis group to develop the necessary concepts for

adaptation of the Northeast Corridor Transportation models for use

as urban transportation analysis tools. Some of these concepts were

directly applicable to the intraurban transportation scene. Three submodels were developed for experimental purposes.

Coast Guard Operations—In response to a Coast Guard request a data base was constructed for analyzing the search and rescue operations of Coast Guard units throughout the country. A computer pro- gram was developed to edit raw data tapes provided by the Coast

Guard, reformat records of operations, sort reported cases by district and operating facility and print summary statistics. The Coast Guard

is using the outputs for each of several years to evaluate hypotheses

concerning the activities of its shore stations.

A second project underway is the construction and exercising

of a simulation model for a researcli and rescue force integration

analysis.

Urhan Studies Projects—The Technical Analysis Division embarked on a cooperative project with the International City ^laiiagers'

Association, Fels Institute of the University of Pennsylvania and the

Department of Housing and Urban Development to determine the

applicability of systems analysis and operations research techniques

to the resolutions of urban problems.

375-572—70 11 l*^^
Numerous cities throughout the couutry have begun to apply systems

techniques to the resolution of varying types of urban problems. Staff

members have recently been involved in an effort to evaluate the state- of-the-art. A forthcoming publication will cite the cities using the

systems methods and the problems to which they have been applied.

The publication will serine as an important source document for government agencies, city staffs, consulting firms and universities active

in the area of urban problems.

During FY 1969, the Division acted as "technical coach'' to the

city staff' of East Lansing, Michigan. A model was constructed which

enabled the city staff to determine the optimal number and location

of fire stations necessary to protect the city now and in the future. In cooj)eration with the Montgomery County School Planning

Board, Maryland, a model was built to determine an optimal school

districting plan. The model was applied to the elementary schools in the Takoma Park area. An operational computer code of a transportation algorithm was modified to meet the districting criteria of the

Planning Board. This methodology reduces the time required to establish these districts.Motor Vehicle Safety

During fiscal year 1969 the Office of Vehicle Systems Research in

the National Bureau of Standards continued its research activities in

tire systems, occupant restraint systems, braking systems, and vehicle

structures. This work is sponsored by the National Highway Safety

Board of the Department of Transportation in order to provide the

technical basis for motor vehicle safety performance standards.

Tire Systems—A major activity of the tire research program was

concerned with developing a uniform quality grading system for motor

vehicle tires to enable consumers to make an informed choice in the

selection of tires. The tasks involve establishing (1) standard methods

of test for the several properties required to evaluate tire quality; (2)

quality levels for each property; and (3) a means of conveying the

information to the consumer. For this system a method for rating the

I'elative tread wear has been developed. It requires the inclusion of

various pavements surfaces, prescribed amounts of cornering, braking,

and acceleration. The tests are designed so that effects of wheel position, vehicle, and weather can be estimated and removed from

consideration in the evaluation scheme.

In progress is work to establish wet traction standards for tires,

standards for resistance to impact damage, and methods for

nondestructive examination of tires. 0cciifant-Restraint Systems—Included in the second series of sled

tests at the HoUoman Air Force Base were exx)eriments involving

human volunteer subjects riding on automotive production seats and

156
restraint-simulating crash levels up to 14 g. The kinematic trajectory

of these subjects has been plotted from the high speed motion picture coverage. Computer analysis of the data from these tests is producing

data on velocity and movement of various body members, seat belt and shoulder harness loading, leg, and muscular reaction, etc. New laboratory procedures are being developed for static and

dynamic sled testing of restraint systems. A test method has been

developed for determining the degree of resistance to lateral intrusion

of various vehicle door systems.

Braking Systems—Eoad test procedures and instrumentation are being developed to measure the safety performance of a braking sys- tem and its components. To establish correlation betAveen road tests and laboratory tests, research programs have included the utilization

of a special purpose double-ended inertia dynamometer, a friction materials test machine, friction assessment screening test machine

(FAST), and a "scale'' machine from England. One of the objectives

of this effort is to develop laboratory methods for safety performance

standards for replacement brake linings.

Recommendations were made to the National Highway Safety Bureau for upgrading the brake fluid regulations with respect to actual

performance requirements and packaging and labeling of fluids. Un157
der development has been a humidity exposure test procedure to

establish percent water pickup by the fluid after one to two years

service. Testing facilities for automotive flexible brake hoses are nearing completion.

Engineering Materials

IAT provides advisory, consultative, and laboratory investigation

services relating to selected engineering materials. The laboratory

work is mainly for the development of test procedures which can be

used by other testing laboratories. The staff responsible for this program works with national and international groups to establish standards for these materials. Services also include establishing a technical

base for other Government agencies to set purchase specifications.

Magnetic Twpes for Satellite Recorders—The early failure of

NASA flight recorders is one of the most important causes of satellite failures. New satellite designs calling for performance for several

years, rather than a few months, magnify the problem. NBS has con- tinued its study of the changes of physical and chemical characteristics

of magnetic tapes during their use. The interactions of tape and head

surfaces are of special concern. Tapes are operated over dummy heads

of known composition, with controlled parameters of atmosphere,

temperature, tape tension, and tape speed. Changes in such properties

as stiffness, hardness, surface roughness, coefficient of friction, and

wetting characteristics are measured. Detection and identification of

material that deposits on heads is carried out by contact angle measurements, interference microscopy, and infrared spectroscopy.

Experimental tapes, expected to have improved stability, have been

produced in this laboratory. These tapes are based on polyimide resins

and have improved friction and hardness properties as well as high

resistance to heat, chemicals, and radiation.

Textile Evaluation hy the Ajyparel Industry—A cooperative program conducted with The Apparel Kesearch Foundation resulted in a book, "Testing Programs for the Apparel Industry—Evaluation of

Materials and Components,-' and a series of training programs based on the book. This work was based on a survey of the industry. The

booklet describes three types of textile testing programs, testing

equipment, its intended use, and approximate price. Test methods

described include those of ASTM, AATCC, and the Federal Government. The training programs presented were fully subscribed and

others are planned.

Plastics Technology—An example of effective consultative and

advisory service is a problem undertaken for the U.S. Navy. The Navy

experienced difficulty in specifying and obtained a very heavy intri- cate polypropylene part that would meet difficult jDcrformance require158
ments. This item is a major component of a new weapons system. NBS

was able to obtain satisfactory parts, by means of a relatively new

forming technique, that had both improved design and mechanical

properties. At the same time the cost of these items was reduced from

approximately $450 each to about one dollar. Collaboratwe Reference Program for Paper—Accurate paper test- ing procedures are of major concern to the pulp and paper industry.

Because of the large volume of production, even small systematic

errors in test values can be very costly. A collaborative reference pro- gram, administered by the Bureau at the request of the Technical

Association of the Pulp and Paper Industry (TAPPI), provides a mechanism for participating laboratories periodically to check the

level and uniformity of their testing in comparison with that of other

laboratories. Test samples are distributed bimonthly to the participants and the results of the test determinations are returned to the

Bureau for an analysis of the data. Reports, in which the laboratories are identified only by code number, are prepared bimonthly and

include test results, averages, and standard deviations for individual

laboratories and for the group as a whole. The first shipment of samples

under the program was made in March 1969 to over 100 participating

laboratories.

Thermal Stability of Modified Celluloses—Differential thermal

analysis (DTA) and thermogravimetric analysis (TGA) are useful

tools for studying thermal stability, phase transitions and changes in structure of materials. These techniques have been used to obtain in- formation on the effects of modifying cellulose through reaction with

specific oxidizing agents to produce varying amounts of aldehyde,

carboxyl and ketone. The nature of the carboxylic acid salt, especially

calcium and aluminum salts, is of interest in relation to papr mill

practice. Aluminum sulfate is widely used in papermaking, and

calcium carbonate is sometimes used as a filler. Cellulose normally shows a massive DTA endotherm at about 350 °C.

The temperature of this endotherm usually is lowered by modifications

made through oxidation, and by covering the carboxyls with aluminum.

The temperature of this endotherm is raised if the carboxyls are con- verted to calcium salts. Thus, aluminum tends to unstabilize cellulose and calcium tends to stabilize it. Aluminum sulfate that is incorporated into paper during the papermaking process is thought to contribute to instability because of

hydrolysis, producing sulfuric acid. Both DTA and TGA data indicate

that the effects of alum and of sulfuric acid are quite different. At the same time, it appears that cross-linking occurs in each case. Flammahle Fahrics—Various combinations of ignition, heat transfer, flame spread, and the liberation of toxic or irritant products of

combustion represent the liazardous characteristics of flammable

159
fabrics and related materials. Research was initiated on the relationships between these fundamental characteristics and with hazards to

life and property. In response to notices by the Department of Commerce that there may be need for new or amended flammability standards for wearing apparel, carpets, and rugs, seyeral test methods are under deyelopment or eyaluation as proposed standards. The notices were based in part on flammability test data obtained and analyzed

by NBS on garments recoyered by the Department of Health, Education, and Welfare from burn cases. NBS technical experts are co- operating with the Department of Health, Education, and Welfare in

the design of better data gathering programs. NBS sponsored a twoday sjanposium on the measurement of flammability. The symposium

was attended by oyer 500 representatiyes of industry, the academic

world, and goyernment agencies.

Engineering Standards

Standards Information—In fiscal year 1969, the Bureau, through its Office of Engineering Standards Seryices took a step toward improying communication among the nation's standards-writing groups by

announcing the ayailability of information on engineering and related

standards and specifications. During the past year, 1,178 standards were added to the collection, bringing the total to 19,000 from 353 U.S.

trade, professional, and technical societies. A Key-Word-In-Context

(KWIC) Index was compiled, which lists the standards alphabetically

by key words in their titles and giyes the number and sponsoring

group for each standard. This Index will aid individuals in deter- mining if there is a standard (or standards) in their areas of interest

and in locating groups that could answer their questions on specific

standards. Standards-writing groups will be able to use the Index

before they initiate a standards project to determine if there is an

existing standard covering the same subject. A need for this type of

information is eyidenced by the 900 inquiries concerning the KWIC

Index which were received between January 1969 and the end of the

fiscal year. About 5,600 inquiries regarding standards and standardization activities Avere received in fiscal year 1969. Product Standards—One standard and two amendments were publislied, five other recommended standards were approved for publication, and 14 were circulated to industry for determination of their

acceptability. Additionally, four proposed standards were circulated

for comment and 29 standards were transmitted for committee approval. Reviews of 312 existing standards were in progress and recom- mendations for withdrawal, revision or revalidation were made on

29 standards.

Consumer Standards—Progress was made on several 2:>rograms of

interest to consumers in fiscal year 1969. A A^oluntary standard for salt 160
packages was approved for publication and four other consumer com- modity packaging standards were initiated. These proposed standards

cover toothpaste, instant nonfat milk, instant mashed potatoes, and

green olives. Another area of consumer interest concerns standards which establish size classifications, according to significant body measurements,

for patterns and apparel. In this area, revisions of the "Women's"

and "Boys' " standards were formally initiated ; under development

were a revision of the "Girls' " standard, and a new standard for male

"Students," and a "How to Measure" standard.

Fair Packaging and LaheJhig—The National Bureau of Standards

has continued to pursue the implementation of the responsibilities

assigned to the Secretary of Commerce under the Fair Packaging and

Labeling Act. With cooperation by producers, distributors, and

weights and measures officials from the states, counties, and cities,

voluntary decisions have been reached covering a significant portion

of the packages subject to the statute. Evidence of industry action in

this area can be seen in the tabulation below and also in the

marketplace.

Percent Reduction in Package Sizes hy Commodity

[Achieved by agreement as of July 1969] Product Percent

reduction

Adhesive bandages 73 Dry breakfast cereal 52 Cheese 36

Cookies and crackers 23 Dry detergents 75

Instant coffee 20

Instant tea 67

Jellies and preserves 37 Macaroni products 50 Mayonnaise and salad

dressing 20 Paper napkin 28

Product Percent

reduction

Paper towels 76 Peanut butter 60

Pickles * 35

Potato chips * 33

Refrigerated dough

products * 24

Salad and cooking oils 53

Soft drinks * 33 Syrups * 20 Tea bags 33

Toilet tissue (1 ply) 20

Toilet tissue (2 ply) 36

Estimated. New State Standards—During fiscal year 1969, seven additional

States received new State standards. Tlie seven included Georgia,

Hawaii, Kentucky, Missouri, North (Jaroliua, Pennsylvania, and Wisconsin. To date, the Bureau, under this program, has provided new

equipment to 30 States. Manufacture of additional sets of precise

physical standards and instruments is continuing and the uUimate

goal is to update all State weights and measures laboratories.

Basic laboratory training (two weeks) has been gi\ en to '2') State metrologists at various State laboratories.

161
Technical Training—The demand for weights and measures training continues to increase. This past year 31 training schools were held, an increase of five over the previous year. These schools were con- ducted throughout the country and at the NBS weights and measures

laboratory. Training included basic laboratory techniques, advanced

courses, and special purpose field work. In addition to techniques used

in the laboratory, the courses cover items such as the effect of the

Fair Packaging and Labeling Act on State and local enforcement

policies of the weights and measures groups ; field testing operations

;

and special training for foreign visitors. Federal agencies, and private

industry.

National Conference on Weights and Measures—The 54th National

Conference on Weights and Measures was held in Washington during

June. Major revisions, based on the past year's experience, were made

in the Model State Packaging and Labeling Regulation. These

changes were made to clarify requirements of the States with respect

to consumer package quantity labeling, and to assure the consistency

of the Model regulation with Federal requirements under terms of

the Fair Packaging and Labeling Act. The Conference updated Handbook 44 "Specifications, Tolerances,

and other Technical Requirements for Commercial Weighing and

Measuring Devices."

Standards Engineering—The engineering staff of the Office of

Weights and Measures identifies, analyzes, and solves technical problems in the measurement area of commerce. During the past year, they

have studied and reported on such diverse subjects as wire and cordage

measuring devices, a new method of calibrating rental car odometers

and taximeters, and propane vapor meters. The vapor meter project

resulted in the adoption of a new tentative code in NBS Handbook 44,

the basic working reference used by weights and measures officials throughout the country. A study to help local weights and measures

officials calibrate grain moisture meters has been initiated. Two new publications concerned with important areas of Standards

and Engineering were distributed during '69 ; NBS Handbook 105-1,

Specifications and Tolerances for Field Standard Weights, the first in a series, and an unpublished report.

TECHNICAL SUPPORT ACTIVITIES

The Institute for ApjMed Technology {IAT) —Provides engineering and development assistance in applying measurement technology

to specific measurement problems. These services are used by other

research programs in the Bureau, and by other Federal agencies. Work

of this nature involves electronic techniques or combinations of elec- tronics with mechanical, thermal or optical methods. It also includes

the production of instrument prototypes. Examples of the services

follow.

162
Performance of AC-to-DC Voltage Transfer Standards—A recently

completed standard is based on coniparino- the average of a rectified alternating voltage with a direct voltage, the principle inherently used

by a majority of x^resent-day AC voltmeters. With this standard, a comparison accuracy of 20 ppm (parts per million) was obtained at audio frequency, increasing to 200 ppm at 100 kHz. This work complements the earlier development of an AC-DC transfer standard

based on comparing the peak value of the alternating voltage with a standard direct voltage.

Laser Emissions—In the field of length metrology, there is much

interest in using particular laser emissions as intermediate leng-th

standards. Such use requires that the laser emission be calibrated

against a primary standard wavelength, a process that is tedious and

time-consuming wdien done manually. Work continued on a scanning

Fabry-Perot interferometer for comparing two light emissions, the

goal being to allow laser wavelength calibrations to be made quickly

and automatically.

Comparing Circular Grooves—A precise gaging method for measuring and comparing circular grooves used to aline the electrodes of precision capacitors. This instrument, which is not a jog or fixture, can

also be used to measure precisely the diameter of circles as well as cir- cular grooves. The importance of this instrument is reflected in the

requirements of the laboratory to align circular vee grooves to an

accuracy of + 0.0001 of an inch or less. TECHNOLOGICAL INNOVATION AND DIFFUSION

Technological imiovation may be defined as that process whereby means are devised and applied for stimulating new technologies,

channeling them in promising useful directions, and exploiting their use for purposes other than those for which they were originally

developed. Technological diffusion, in the context of lAT programs,

is largely restricted to disseminating the results of Government sponsored R&D.

Invention and Innovation

The Office of Invention and Innovation is the lAT activity which

helps to develop an environment conducive to technological change.

Its basic program has three aspects: providing a national basis for

formulation of climate-setting Federal policies, oft'ering assistance to inventors, and education.

In FY 1968, the Office assumed responsibility (as assigned by the

Assistant Secretary of Commerce for Science and Technology) for ilie program, planning and budgeting activity of the Department of Commerce Technology Program. Department programs included in this responsibility are the Patent Office, Office of State Technical Services,

163
the NBS Clearinghouse for Federal Scientific and Technical Information and the Office itself. Organization of American States—At the request of the Director

of the National Bureau of Standards, the Office conferred with a Working Group of the Organization of American States to devise a strategy for the technological development of Latin America. The

recommendations of the Working Group were considered at the 1969

Trinidad meeting of the OAS Cultural Council.

Invention Programs—Twenty-four states held invention ex]30sitions

and inventors' seminars during fiscal 1969 and several other states are planning to join this effort. The programs are organized and con- ducted by state organizations and universities and are aimed at facili- tating the licensing, development, and exploitation of inventions. NBS

provides assistance in planning and undertaking the expositions and

also provides experts for the seminar programs.

Invention Policy—The Office of Invention and Innovation, m co- operation with the National Inventors Council, embarked on a policy

study to determine the role of the Department of Commerce in encour- aging and providing assistance to independent mventors and inventorentrepreneurs. The study will analyze the problems faced by inventors

and inventor-entrepreneurs who seek to bring their inventions to fruition, describe present programs and mechanisms for aiding them,

identify deficiencies in these methods of assistance, and explore alter- native ways in which the Department of Commerce and other agencies

could properly help to overcome these deficiencies. Education for Innovation—A study of the role of the Department

of Commerce in the education of prospective inventors, imiovators and

entrepreneurs is being conducted in cooperation with the National

Inventors Council and the American Society for Engineering Education. It is a sequel to the 1965 National Conference on Creative Engineering Education, which was organized by the Commerce Department. The study will determine what has been done to promote creative

education since the Conference and what needs and opportunities

now exist with respect to the education of prospective mventors, inno- vators and entrepreneurs. The study will provide the basis for a report

by the National Inventors Council to the Secretary of Commerce.

Innovation Studies—An analysis of policies to promote technological innovation is being performed in conjunction with the George

Washington University Program of Policy Studies. This study stems

from two earlier events—one, the report to the Secretary on "Technological Innovation: Its Environment and Management," and the

other, an agreement by NBS with the Arms Control and Disarmament Agency to assist them in the formulation of policies that would

ease the impact of a substantial cut-back in defense spending on hightechnology enterprise and put to salutary use the resources thereby

164
released. Among the aims of the study are the development of a descriptive model of the processes by which technology is created, applied

and diffused; an evaluation of specific federal programs and policies

that could or do influence these processes; the development for comparative analysis of innovation profiles of selected defense and civilian

industries ; and the identification of key leverage points in the model

where policies may be beneficially applied.

165

CENTER FOR RADIATION RESEARCH

The Center for Radiation Research (CRR) develops improved tech- niques and instruments for detecting and measuring- ionizing radiation, obtains basic data on the interactions of radiation with matter,

and investigates the structure of the various forms of matter. The

center also maintains radiation sources and standards for providing

national services essential to industrial, medical, and research applications. Radiation of concern to the Center is that with energies between approximately 5 keV and 300 MeY, produced by radionuclides,

reactors, and particle accelerators. Because of its unique facilities and competences, the Center not only

has responsibility for carrying out the NBS mission in the area of

radiation, but also for making its resources and capabilities available

to other Government agencies, industry, and universities. Tliis policy

of facility sharing ensures efficient utilization of large multipurpose

facilities, such as the reactor and linear accelerator, by making them

available to a broad segment of the scientific community. A number of

collaborative programs are now functioning successfully, in which

university and Center scientists are jointly performing experiments of

mutual interest. Approximately one-half of all the g-uest workers cur- rently at NBS are working in the Center. Although the programs of the CRR are complex and diverse, they can be grouped roughly as follows

:

1. Radiation Measurement and Standards

2. Nuclear Physics Research

3. Radiation Theory

4. Structure of Materials

5. Facilities Operations

6. Technical Assistance to Others

The experimental research effort is supported by a broad theoretical

effort aimed at interpretation and analysis of the results. Radiation Measurement and Standards

CaloTimetric Dosimetry hy Means of RefrdctoDietry—An interferometer has been designed and constructed for measuring small changes

in refractive index. In a transparent medium, the refractive index will 167
change due to a temperature rise resulting from radiation energy

deposition. The interferometer, functioning as a refractometric calori- meter, is capable of measuring doses from 1 kilorad to 5 megarads at dose rates from 200 rad/s to 5 megarad/s. Measurements can be made,

without the need for cables or heat-sensing probes, in any transpiarent

medium for which the temperature-dependence of the index is known

or can be determined. It is possible to make a spectrophotometric analysis of the irradiate sample simultaneously with the interferometric

measurements.

Energy Devosttion hy Electrons in Aluminum—Energy-absorbed

distributions at various depths in aluminum have been measured with

silicon detectors for normally incident monoenergetic electrons with

energies of 0.5, 0.75, and 1.0 MeV. Pulse-height distributions were

recorded from silicon {Z=14z) transmission detectors with thicknesses

of about 100 and 200 ^mi at depth intervals of about 200 jxm in aluminum (Z=13). From a knowledge of the response of the detectors, the

pulse-height distributions were converted to energy-absorbed distri- butions. The data yield both (1) the probability per incident electron

that a specific amount of energy will be deposited in a given layer and

(2 ) the total energ}^ deposited in a given layer of aluminum.

X- and Gamma-Ray Instrument and Source Calibrations—Fiftysix conventional roentgen meters with 200 condenser ionization chambers were calibrated in exposure units at various energies. Instruments

capable of higher precision in exposure measurement are being submitted in greater numbers, with 20 such devices having been cali- brated. In addition, the x- and gamma-ray facilities have been used

for standard exposures to various kinds of thermoluminescence

dosimeters.

Twenty-one small gamma-ray sources were calibrated in exposure

units, including five cesium- 137 sources. The capability for calibrations of small cesium-137 sources was only recently established.

A program has been drawn up for a,utomating and computerizing

the exposure-calibration facilities. Part of the equipment for auto- matic handling has been constructed in Bureau shops, and contracts have been awarded for additional items, including data-acquisition

equipment.

Thermoluminescence Dosimetry—-V^ovk Avas completed on a comparison of the thermoluminescence (TL) sensitivity of LiF and

CaFs : Mn for ^^Co gamma rays and 15-MeV electrons ; no difference was found in the sensitivity of these materials exposed to the two types

of radiation. The measurements of TL response of CaFs : Mn irradiated

in a CaFsmedium to electrons between 1 and 4 MeV were not reproducible, possibly because the response was i-ufluenced by a nonreproduoible electron-charge distribution in the (insulating) CaFg medimii.

Work on this problem is continuing.

168
A search, for a possible dependence of 7^- center formation in LiF

on the ganuna-ray exposure rate turned out negative for rates between

about 1.5X103 and 5X10^ E/h. TMs result is compatible with the

dominjant role given F-centers in some of the current models for the

thermoluminescence process in LiF of TLD grade.

Dose Distributions Measured with Radiochromic Dyes—Thin foils of approximately 1 mg/cm^ containing stabilized dye precursors have

been used successfully to measure gamma-ray and charged-particle

energy deposition in extended media. The production of dye by irradiation is measured spectrophotometrically in terms of increase in optical

density. The response does not vary appreciably over wide ranges of

radiation energy and intensity. Experimental measurements of energy

deposition as a function of depth of penetration of high-energy elec- trons and protons in various substances have shown reasonably good

agreement with theoretical Monte Carlo calculations. Energy deposition in inhomogeneous media irradiated with gamma rays has also

been measured with high resolution, using the thin-dye systems placed

across interfaces of different materials.

Monito7ing of High-Energy Electron Beams—The development of

nonintercepting beam monitors employing ferrite toroids as pulse

transformers has been refined to permit measurement of high-energy

pulsed beams with an accuracy of the order of 0.1 percent for pulsed

current well below 1 mA. The absolute accuracy of our high-energy,

The color density of a radiochromic dye film is lueasiired after electron irradiation. Density variations indicate changes in the dose distribution of the electron beam.

169
high-beam-power Faraday Cup is being studied by using the nonintercepting monitor to measure directly the difference between beam cur- rent and current collected by the Cup. These differences can be repro- ducibly measured to within a few hundredths of a percent of the total current. Differences of a few tenths of a percent due to secondary elec- trons produced in the vacuum window of the Cup and back-scattered

electrons are observed and are being investigated.

Reactor Flux and Power Measurement—The neutron flux and

power distribution in the NBS reactor were determined using new

techniques developed at the Bureau as well as more standard methods.

The usual thermal flux measurement technique of activating cobalt

wires was supplemented by the activation of tungsten wires which

were used to determine the epithermal flux by comparison to the cobalt

measurements. The absolute value of the neutron flux was determined

by activating a cobalt-^^B glass bead. The relative power distribution was also determined independently by gamma-scanning each fuel ele- ment individually in a reproducible geometry. The power distribution

determined in this way agreed with that from the flux measurements

Avithin a few percent, demonstrating the feasibility of the gamma-scanning technique.

Neutron Cross Sections—The total neutron cross sections of hydrogen, aluminum, calcium, titanium, iron, and nickel were measured in

the neutron energ}^ range 0.5 to 15 MeV. The neutron time-of-flight

method was employed, with the NBS electron linear accelerator used as the pulsed neutron source. The energy resolution varied from 0.2 per

cent to 0.9 percent ; both the statistical precision and the normalization

accuracy were better than 2 percent. Tlie hydrogen cross section was

measured in order to check a recent suggestion that this cross section

may not be smooth, but may have some structure. Our measurements

showed that the cross section was, indeed, smooth. The rest of the

elements measured are important constituents of shielding or construction materials, and the measurements were made primarily for the

purpose of providing data to be used in transport calculations.

Cher)iical Dosimetry—A study has been completed on the systematic errors which may be introduced in the spectrophotometric deter- mination of ferric ion concentration by incorrect evaluation of a nonlinear calibration curve of the spectrophotometer. Several methods

have been developed for using correctly a nonlinear relationship be- tween absorbence and molarity, in calculation of absorbed dose. Radioactivity Standards—A total of 341 radioactivity standards were sold in fiscal year 1969. Fifty-one source calibrations were made

:

41 for other agencies and companies and 10 for XBS laboratories. Fif- teen series of standards were produced totalling 1359 units, five of these

series were prepared for use with Ge(Li) detectors. Two new stand170
Preparations of neutron time-of-flight experiment to measure neutron cross sec- tion of hydrogen (polyethylene sample at left-center). A compensating carbon

sample is being adjusted.

Absorbed-dose measurement, apparatus showing the absorber wheel :iih1 ,i;i-;ii>lute calorimeter l>lock. Kcmote-control oiterntion < Ii:iiig('s I be .-ibsorlu'r lliickness and moves the calorimeter and comparison standards (not shown) parallel

and perpendicular to a beam of electrons or x-rays. 375-572—70 12 171
ards were developed: plutoninm-238, wliicli is the first NBS alpliaparticle disintegration-rate standard ; and tlioriiun-228-tlialliiim-208

gamma-ray standard, for wliicli a new method of calibration was developed utilizing alpha-particle and ganmia-ray comiting methods. Work

is almost complete on two new reference materials—nickel-63 solution

standard and krypton-85 gamma-ray gas standard.

High-Energy Electron and Photon Ahsorhed-Dose Standards—

A

calorimeter mtended to be the basis for the Bureau's absorbed-dose

calibration service was constructed and all tests preliminary to actual use were completed. The instrument will be used initially to determine

the dose deposited in carbon by electron beams with energies from 30 to oOMeY.

Cohalt-GO Source Calihration—The exposure rate from a cobalt-60 source furnished by the National Research Council, Ottawa, Canada, was measured with the Bureau's standard cavity chamber. The meas- ured rate agrees within 1 percent with the rate predicted from the

power output of the source as determined by calorimetry.

Hlglx-Intem'dij Monoenergetic Photon Beams—Experimental

studies are being carried out to develop high-intensity monoenergetic

photon beams in the energy region from approximately 0.5 to 100 keV.

These beams will be produced with electron accelerators by direct elec- tron excitation of K x rays in different targets. It is expected that for

direct current accelerators, the beam intensities will be approximately

three orders of magnitude larger than the current methods in wliich

K X rays are produced by photon rather than by electron excitation.

Nuclear Physics Research

High-Energy Electron Scattering—A broad program of highenergy electron scattering is conducted using the XBS electron linac. The experimental apparatus is capable of measuring the spectrum of

scattered electrons with a resolution of 0.08 percent. Inelastic scatter- ing from ^-C has been studied, concentrating on the excitation region

17-27 MeV. The low lying excited states of ^^O have been examined in an experiment made feasible by the unique high-resolution capability

of the apparatus. In particular, it was possible to resolve the first two

excited states near 6 ]MeV, separated by only 80 keV, and measure their

form factors. This work is expected to contribute substantially to our understanding of the structure of this nucleus. Other experiments in progress are aimed at measuring the properties of the nuclei ^^C, 19^^^46X1^ 4sxi^ 50Ti^ ssgj,^ ^^-^^ sgy. Many of these experiments are collaborative efforts with research teams from a number of universities.

A study is in progress to measure the cross section for scattering

of electrons from protons. The NBS apparatus is particularly well

suited for this work in which the aim is to measure this very fmida172
mental cross section with an accuracy substantially better than one

percent.

Nuclear-Structure Studies hy Electron and Photon Excitation—

The program to investigate the systematics of nuclear energy levels excited by electrons and photons is continuing. Experiments being

actively carried on include excitation of nuclear levels in isotopes of

hafnium, iridium, gold, and erbium with the possible inclusion of

tungsten and mercury being considered. Systematic variations in the

energy structures of these nuclei are being studied and the results being compared with existing theoretical calculations.

Heawy-Ion Spectrometer Experiments—Successful and reliable

operation of the heavy-ion spectrometer to measure charged particle

spectra and angular distributions was achieved. Measurements were

started on the cross section for the reaction, ^He(7,<i)D. An agree- ment was made with the University of Illinois to carry out a collaborative experiment to measure the cross sections for the photodisintegration of the mass-3 nuclei ( and ^He)

.

Nuclear Spectroscopy—Th^ nuclear orientation of radioactive irid- ium-192 in a ferromagnetic matrix was studied in detail. The angular

distribution of gamma rays and conversion electrons with respect to the nuclear spin direction was measured for eight electromag-netic

transitions and the multipolarity mixtures for each of these transitions

determined. A measurement of the beta ray angular and energy

distributions determines the tensor rank of the matrix elements con- tributing to the beta transitions. A solid state beta detector and pre- amplifier operating at a temperature of 1.5 K and large germanium

gamma ray detectors provided the necessary resolution and efficiency.

Inelastic Electron Scattering—Following a previous large-angle,

moderate-energy experiment, the data are being extended to include

higher incident energies (up to 3 MeV), forward scattering angles

(less than 90°), and low atomic number targets. These parametric

studies are being carried out to determine the effects of the atomic

binding of the target electrons on the observed scattered electron

spectra. Disturbing variations from the available theoretical calculations are still evident and the data are now in the process of beinganalyzed.

Inelastic Electron Scattering Gross Sections—Investigations of

inelastic electron scattering for 100-, 200-, and 400-keV electrons

have shown low and high energy tails in the energy spectra of inclastically scattered electrons. In addition, the angular distribution of

these electrons over the region from 20 to 180 degrees has shown a

sharp maximum in the region of 90 degrees.

Isospin Sum Rules for Photonuclear Reactions—The study of the

electro-magnetic aspects of the three-nucleon system has continued.

Three sum rules for the two isospin components in the "TI and ^He

173
pliotodisintegration reactions have been derived. One of these rules

relates the plioton absorption cross sections to the charge radii of the

nuclei. This rule has also been generalized to other nuclei and provides

a valuable guide to the prediction of the strengths of photoabsorption

cross sections of the two final isospin states. The Pliotonvclear Data Center—Compilation and abstracting activities have continued along with the preparations for publication of the

second supplement to Miscellaneous Publication 277, the Photonuclear

Data Index. This supplement, scheduled for publication early in FY

70, will be an index to data published from January 1965 through

the first half of 1969. Work was started on building up a computerbased library of photonuclear cross-section data. Over 150 cross-section curves have been digitized and entered in the data file. Radiation Theory

High-Energy Physics—Assuming SU(6)^ invariance of the meson- baryon amplitudes and a universality principle which connects these

to the photoproduction amplitudes, it has been possible to describe the

energy dependence of many forward photoproduction jorocesses involving pseudoscalar and vector mesons. For example, results obtained for

the ratio ^ ^^^^'^^^^^

}

disao^ree with the simple quark model but fit Qiuch better with the experimental results. Encouraged by success in the photoproduction work, efforts were

directed to the meson-baryon processes in an attempt to make some

sense out of the apparent tremendous breakings of the symmetry

there. It was found that the symmetry is broken in a rather regular,

though still not understood, way which nevertheless allows quantitative predictions for forward and backward meson-baryon reaction

cross sections. 2Ieson Effects—A model calculation of the photoj)roduction of tt mesons from nucleons was completed, and numerical results which

agree fairly well with existing experiments were obtained by fitting a single parameter. A calculation of the anomalous magnetic moment

of the cleuteron, allowing the admixture of nticlear resonances (X*3_3

(1236), X*i_i(1470)) in the wave function, was made. Results were

such as to improve agreement of existing calculations with experiment.

Finite energy sum rules were used to predict high energy behavior of

meson-baryon scattering amplitudes, tising low energy experimental

data for these processes as input. Xew mathematical properties of the

finite energy sum rules were explored and exploited.

Electron Transfort Theory—In continuing study of electron trans- port using Monte Carlo techniqties, calculations have been made of

electron transmission and reflection, energy deposition, and brem174
sstrahlung production in thick targets. Specific applications have in- cluded determination of the spatial distribution of energy deposition

in the atmosphere by auroral electrons (2 to 20 keV), in the presence

of the earth's magnetic field ; calculation of the response of Si detectors

to electrons with energies from 0.15 to 5.0 MeV; and calculation of the

electron flux generated in water by electrons and bremsstrahlung

beams with energies up to 60 MeV.

A code has been developed which will calculate the energy deposition by electrons in multilayer media. These calculations have

applications in determining the dynamic response of solids by laser interferometric techniques. The production of characteristic K x rays

and bremsstrahlung has also been calculated.

Quantum Electrodynamics—Higher order radiative corrections to the scattering of electrons from nuclei at high momentum transfers were studied with the aim of permitting more accurate analysis of data

from the newer linear accelerators. In particular, radiative corrections

to the scattering cross section in second Born approximations, and the

radiative tails in the same approximation, are being calculated.

Time Reversal—The first direct demonstration that time reversal

symmetry {T) is violated in K° meson decay has been given. Heretofore T violation has only been inferred indirectly via the known CP

violation and the OPT theorem. However, OPT symmetry itself is being tested in K° decays. (The T test is more sensitive.) This work was

published in a journal series and has received attention in the technical news magazines. It is relevant to the current search for an electric dipole moment of the neutron, in which the NBS high-flux reactor may

play a role. The mathematical techniques involved in K° decays have also been

applied to a study of energy transfer between impurities in matter. Mechanisms of energy transfer are currently of biologic interest. Additional papers on charge transport in stressed matter and on photoproduction of phonons have been prepared.

Structure of Materials

Dynamics and Interionic Forces in Pliosflionium Salts—The vibrational and rotational dynamics of pliosphonium lialide crystals have

been studied by Laser-Kaman and NMR spectroscopy in cooperation

with other groups at NBS and the University of Maryland. A comparison of the spectroscopic results with previous structural information suggests that the crystal potential hindering the rotation of the

pliosphonium ions is dominated by short-range rei)ulsivo forces. The

results are in sharp contrast to those for the isostructural ammonium

salts. It is hoped that continued neutron diffraction and inelastic

scattering studies on these crystals, combined willi theoretical cal- 175
culations, will yield generally consistent force models for both

ammonium and phosphonium salts. Phase Transitions in Metal Hydrides—The lattice vibrations and

diffusion of hydrogen in several phases of vanadium hydride have

been studied by quasielastic and inelastic neutron scattering in collab- oration with scientists at Argonne National Laboratory. The

a <—> ^ phase transition has been shown to be associated with a very

large change in the hydrogen diffusion rate. In addition, an abnormally low activation energy for diffusion and a large concentration

dependence for the diffusion is found in the a phase. These observations, coupled with significant differences in the vibration spectra

for the a, ^, and yphases, suggest that the transitions are associated

with a reordering of the hydrogens. The implications of these results with respect to the properties of other transition-metal hydrides are being studied.

Facilities Operations

Linear Accelerator—During fiscal year 1969 approximately 1700

hours of beam time were provided for experiments using the NBS

linac. This was 63.4 percent of the scheduled beam time. Continued

modifications to the accelerator and beam transport equipment have

been accomplished to improve beam quality and reduce maintenance.

The fraction of the scheduled time during which beam was delivered

to experiments has increased 11 percent over the corresponding figure

for FY 68. This increase was largely due to the fact that for about

20 percent of the year it was possible to operate the linac round-theclock on a four day a week schedule. The beneficial impact of this

round-the-clock operation was somewhat impaired by a series of

injector problems, but was still very significant both to the accelerator

performance and to experiments.

Experiments using the accelerator include programs in electron

scattering, photoneutron production, production of heavy ions, meas- urement of neutron total absorption cross sections, studies in beam

monitormg, tests of accelerator theory, programs in activation

analysis, and production of radioactive sources for materials studies

using Mossbauer sources and for studies of photonuclear reactions.

Programs in electron and x-ray beam dosimetry, accelerator research,

production and use of monoenergetic positron and photon beams,

studies of transient chemical reactions, and studies of neutron capture

gamma rays are in preparation.

Use of the linac by organizations outside of CKR has increased

appreciably during this period. For groups outside of NBS most of

this use is in collaborative programs with NBS personnel. There are presently 25 Guest Workers representing 12 organizations outside

NBS (mostly universities) involved in programs using the linac. Most

176
of these Guest Workers spend a relatively small fraction of their

time at NBS, doing the analysis of their data at their home institutions. Experimental data-taking for two doctoral theses was completed this year, with preliminary data-taking started for five other

doctoral candidates. Work using the NBS linac that was supported by

six other government agencies was carried out during this period.

Accelerator Research— problem of long-standing interest in the

theory of linear electron accelerators is the ultimate beam current

possible for extremely short, high-intensity beams. This question is directly related to the energy lost by such a beam due to microwave

excitation of the accelerating structure. The loading by very short

beam bursts might be expected to be large due to the broad frequency

spectrum implied by short beam bursts ; however, theoretical estimates

of these effects differ considerably in the magnitude of the effect, and

even in the dependence on electron energy. The existence of enhanced

beam loading for short pulses is of particular importance for a new

electron ring accelerator concept presently being studied in the USSR

and at the University of California. An experiment has been per- formed to measure these effects using low beam currents under ]3re- cisely controlled experimental conditions. The energy lost by a very

short (few nanosecond) electron beam pulse in passing through an

accelerating waveguide was measured. Energy shifts of a few parts

in 10^ were detectable. Enhanced beam loading, consistent with some

theoretical predictions, was observed.

i-MeV Accelerator—Improvement and updating of the NBS l-MeV

Van de Graaff electron accelerator is continuing, with most modifications occurring in the peripheral experimental equipment to increase

its flexibility and usefulness for the largest possible number of diverse

experiments. Such improvements are typified by the addition of a new

180° scattering chamber designed to study electron-produced gamma

and X rays at large scattering angles. The existing 18-in scattering

chamber has also been outfitted with a new target-holding mechanism

which allows the experimenter to mount a variety of different targets

and to change the inclination of the target to the incident beam direction without cycling the vacuum system. In addition to the experimental programs of the Bureau, a number of outside users have and are

utilizing this facility for numerous experimental projects.

180 MeV Synchrotron—The move of the NBS Synchrotron from

the old NBS site to Gaithersburg was completed early in the fiscal year. Electron beam current is generally about twice what it was in Washington with better stability. The accelerator is used almost exclusively

as a far ultraviolet light source by the Atomic Physics Division, IBS.

With new experimental apparatus the light may be used at several

points simultaneously, thus greatly increasing utilization of the

accelerator. 177
Far ultraviolet light is trausmiried tLrougL taugential port ( left-f ure;^ruuiid i of donut resting on magnet of NBS Synclirotron—seen here from above.

Isotope Separator—A large number of irradiations liave been car- ried out with the isotope separator in the last year. Oxygen and neon

isotopes Tvere implanted into niobium foil for Pennsylvania State University for nuclear-excitation experiments : iron-57 was implanted

into aluminum in connection with the development of a Mossbauer

detector for the XBS Analytical Chemistry Division and the Atomic

Energy Commission ; alimrLnum-27 and chromitun-52 were implanted

into silicon crystals, and krypton-86, on a special target, for the Xaval

Eesearch Laboratory: bismutli-209 was irradiated in the XBS linear

electron accelerator and separated and examined in the low-level

counting facility, with some indication of radioactivity down to mass

200. A technical note on praeseodymium profiles and penetration in

iron foils, in connection with nuclear orientation experiments, was pre- sented at the International Isotope Separator Conference held in

Brookliaven in Septemljer 1969.

Technical Assistance to Others

SliieJding for Civil Defense—Changes in the methods used by the

Office of Civil Defense to calculate shieldmg properties of structures agauist fallotit. which were recommended by XBS. have been adopted

by OCD. Reconmiendations on procedures for calculating protection

from nuclear weapons are being generated by XBS.

178
Particle Accelerator Conference—The third Particle Accelerator

Conference was held at the Shoreham Hotel, Washington, D.C. on March 5-7, 1969. Approximately 800 persons from industry, national

laboratories, universities, and Government agencies attended. Although it was organized as a national conference, the proceedings were

enriched by significant foreign participation. The purpose of the Conference was to promote and to facilitate communication among sci- entists and technologists engaged in the planning, design, and operation of all types of particle accelerators and related devices.

179

APPENDIXES

ORGANIZATION OF THE NATIONAL

BUREAU OF STANDARDS^

The Bureau is headed by a Director who is appointed by the President with the advice and consent of the Senate. The Director is assisted

in the overall management of the Bureau by a Deputy Director. An

Associate Director for Administration is responsible for the planning

and operation of facilities and of administrative management services in support of the Bureau's technical programs. An Associate Director for Information Programs is responsible for the dissemination

and accessibility of scientific and technological information.

Technical program activities are conducted in three Institutes and

two Centers. Each is headed by a Director who is responsible for the

development and direction of research programs and central national

services essential to the fulfillment of a broad segment of the Bureau's

mission. These major organizational units are

:

(1) The Institute for Basic Standards, which includes the Office of

Measurement Services and 11 technical divisions (5 in Boulder, Colorado) each serving a classical subject matter area of science and en- gineering; also in IBS are 3 administrative divisions serving the

technical divisions located at Boulder

;

(2) The Institute for Materials Research, which consists of 6 di- visions, organized primarily by technical field ; (3) The Institute for Applied Technology, which inchides 10 divi- sions oriented to high technology industries

;

(4) The Center for Radiation Research, which includes 4 divisions

concerned with the theory and a])plicati()n of radiation; and

(5) The Center for Computer Sciences and Technology, wliich

includes 5 divisions concerjied with the selection, accjuisition, Mud

utilization of automatic data processing e(iui})nKuit.

1 As of June 30, 1969. 181
DIRECTOR

Allen V. Astin*

DEPUTY DIRECTOR

L. M. KUSHNER

OFFICE OF THE DIRECTOR

Assistants to the Director

G. E. AmiAN

C. COATES

R. D. HUNTOON

A. G. McNisH

Special Assistant for Program Planning

R. E. Ferguson

Legal Advisor

A. J. Faerar

Office of Academic Liaison

S. SlLA^RMAN

Senior Research Fellow

C. ElSENHART

Staff Units Reporting to the Deputy Director

Office of Industrial Services G. S. Gordon

Office of Engineering Standards Liaison A. A. Bates

OFFICE OF ASSOCIATE DRECTOR FOR ADMINISTATION

R. S. Walleigh

Deputy Associate Director

P. H. SCHRADER

Patent Advisor

D. ROBBINS

Accounting Division

Administrative Services Division

Budget Division

*Dr. Astin retired on August 31, 1969. 182

J. P. Menzee

G. W. Knox

J. E. Skillington
Management and Organization Division J. T. Hall

Personnel Division G. R. Porter

Plant Division H. Graham

Supply Division K H. Taylor

OFFICE OF THE ASSOCIATE DIRECTOR FOR

INFORMATION PROGRAMS

E. L. Brady

Assistant for Program Coordination and Evaluation

P. H. Kratz, Acting

Office of Standard Reference Data D. R. Lide, Jr. Atomic and Molecular Data Data Systems Design

Chemical Kinetics Mechanical Properties

Colloid and Surface Chemistry Nuclear Data

Information Services Solid State Properties

Thermodynamics and Transport Data

Clearinghouse for Federal Scientific and Technical

Information H. E. Sauter

Document Distribution Joint Publications Research

and Reproduction Document Processing

Automated Systems and

Services

Administrative Operations

Office of Technical Information and Publications W. R. Tilley

Special Activities Photographic Services

Editorial Graphic Arts

Publications Computer Assisted Printing

Library Division E. L. Tate

Resources Development Reader Services

Library Auxiliaries

Office of Public Information A. V. Gentilini

Office of International Relations II. S. Peiser, Acting

183
INSTITUTE FOR BASIC STANDARDS

Director

E. Ambler

Assistant Director

R. J. COREUCCINI Deputy Director, Institute for Basic Standards/Boulder ^

B, W. Birmingham

OflSce of Measurement Services

J. M. Cameron

Applied Mathematics E. W. Cannon

Numerical Analysis Statistical Engineering

Operations Research Systems Dynamics

Electricity Division C. H. Page

Resistance and Reactance High Voltage

Electrochemistry Absolute Electrical Electrical Instruments Measurements

Metrology Division K. G. Kessler, Acting

Photometry Length

Image Optics and Photography Engineering Metrology

Colorimetry and Spectrophotometry Mass and Volume

Mechanics Division L. K. Irwin

Sound Hydraulics

Vibration Measurements Aerodynamics

Engineering Mechanics Pressure Measurements

Rheology Vacuum Measurements

Fluid Meters Humidity Measurements Heat Division R. P. Hudson

Heat Measurements Statistical Physics

Cryogenic Physics Temperature

Equation of State Radiation Thermometry

Atomic and Molecular Physics Division K. G. Kessler Spectroscopy Molecular Spectroscopy Infrared Spectroscopy Electron Physics Far Ultraviolet Physics Atomic Physics

Plasma Spectroscopy

Radio Standards Physics Division^ H. S. Solid State Electronics Quantum Electronics Plasma Physics

Boyne

Radio Standards Engineering

HF Impedance Standards

RF Transmission and Noise

RF Power and Voltage

Division ^ R. C. Sangster

Microwave Calibration Service Microwave Circuit Standards

Electromagnetic Field Standards

Time and Frequency Division ^

Frequency-Time Dissemination

Research

J. A. Barnes Frequency-Time Broadcast Services

1 Located at Boulder, Colorado.

184
Atomic Frequency-Time Standards

Laboratory Astrophysics Division ^ L. M. Branscomb*

Cryogenics Division^ D. B. Chelton, ActingCryogenic Technical Services Properties of Cryogenic Fluids Cryogenic Data Center Cryogenic Systems

Cryogenic Properties of Solids Cryogenic Metrology

Cryogenic Fluid Transport Processes Administrative Services Division ^ B. F. Betts Supply Office Services Drafting Services Instrument Shops Division^ W. A. Wilson

Instrument Shops 1 & 2 Welding-Sheet Metal

Glassblowing Shop

Plant Division ^ E. A. Yuzwiak

Construction-Maintenance Special Services Custodial Services INSTITUTE FOR MATERIALS RESEARCH

Director

J. D. Hoffman

Assistant Director

E. Horowitz

Office of Standard Reference Materials J. P, Call, Acting

Analytical Chemistry Division W. W. Meinke

Radiochemical Analysis Microchemical Analysis

Spectrochemical Analysis Analytical Mass Spectrometry

Electrochemical Analysis Organic Chemistry

Analytical Coordination Activation Analysis

Chemistry

Separation and Purification Polymers Division R. K. Bby, Acting

Polymer Dielectrics Dental Research

Polymer Chemistry Polymer Characterization Polymer Crystal Physics Polymer Interfaces Molecular Properties Thermophysical Properties

Metallurgy Division E. Passaglia

Engineering Metallurgy Corrosion

Alloy Physics Metal Physics

Lattice Defects and Micro- Electrolysis and Metal Deposition

structures

Crystallizaticm of Metals

Inorganic Materials Division J. B. Wachtman, Jr. Inorganic Chemistiy Physical I'roix^rties Inorganic Glass Crystallography

High Temperature Chemistry Solid State Physics

Physical Chemistry Division J. R. McNesby, Acting

Thermochemistry Mass SiwH-tronietry Surface Chemistry I'hoto Chemistry

Elementary Processes Radiation Chemistry

*Dr. Branscomb became director of the National Bureau of Standards on September 1, 1969.

1 Located at Boulder, Colorado. 185
INSTITUTE FOR APPLIED TECHNOLOGY

Director H. E. SoEEOws, Acting

Deputy Director M. W. Jensen, Acting

Office of Engineering Standards Services D. R Macl^ay

Product Standards Section Information Section Mandatory Standards Section

Office of Weiglits and Measures T. M. Stabler, Acting

Office of Invention and Innovation D. V. DeSimone

Innovation Studies Program Invention Programs

Engineering Education Program

Office of Veliicle Systems Research P. J. Brown

Tire Systems Occupant Restraint Systems

Braking Systems

Product Evaluation Division S. B. Newman*

Plastics and Textiles Paper Evaluation

Fibrous Systems Fabric Flammability

Viscoelastic Materials

Building Research Division J. R. Wright

Structures Materials Durability and Analysis

Fire Research Codes and Standards

Scientific and Professional Liaison Building Systems

Sensory Environment Branch

Environmental Engineering Psycho-physics

Building Transport Systems

Electronic Technology Division M. G. Domsitz

Semiconductor Characterization Instrumentation Applications Electron Devices Semiconductor Processing

Technical Analysis Division W. E. Cushen

Transportation and Highway Studies Economic Analysis

Systems Analysis and Human Development of New Methodology

Factors Instrument Shops Division F. P. Beown

Instrument Shops 1-5 Optical Shop

Glassblowing Tool Crib Welding and Sheet Metal Electroplating Shop Measurement Engineering Division G. F. Montgomeey

Electronic Instrumentation Electronic Optical Development

Microwave and Mechanical Instrumentation

CENTER FOR RADIATION RESEARCH

Director

0. O. Muehlhause

Deputy Director

R. S. Caswell

Radiation Theory Health Physics

*Now M. R, Meyerson. 186
Reactor Radiation Division R. S. Carter

Reactor Operations Neutron Solid- State Physics

Engineering Services Radiation Effects Linac Radiation Di^iision J. E. Leiss

Linac Operations Photonuclear Physics

Radiation Physics Instrumentation Electronuclear Physics

Nuclear Radiation Division H. H. Landon

Nuclear Physics Radioactivity

Nuclear Spectroscopy Section Applied Radiation Division J. W. Motz

X-Ray Physics Dosimetry

CENTER FOR COMPUTER SCIENCES AND TECHNOLOGY

Director H. R. J. Grosch

OflBce of Information Processing Standards J. O. Harrison, Jr. Planning and Coordination Software Standards

Hardware Standards Applications and Data Standards

ADP Management Standards

Office of Computer Information. Computer Services Division Business Applications

Scientific Applications

Systems Development Division- Programming Research

Information Science

M. R. Fox

W. B. Ramsay

Computer Operations

Systems Programming and Training

C. T. Meadow

Management Systems

Instructional Systems

Information Processing Technology Division J. P. Nigro Measurement Automation Computer Systems

Performance Measurements FIELD ESTABLISHMENTS

Institute for Basic Standards

Metrology Division Field Station

:

Visual Landing Aids Field Laboratory

Time and Frequency Division Field Station: Standard Frequency Station WWV-WWVL-WWB

Standard Frequency Station WWVH

Laboratory Astrophysics Division Field Station

:

Poor Man's Relief Mine, Four-Mile Canyon

Institute for Applied Technology

Office of Weights and Measures Field Stations: Master Railway Track Depot

Areata, California Fort Collins, Colorado

INIaui, Hawaii

Boulder, Colorado

Clearing, Illinois

375-572—70 13 187
SUMMARY OF NBS STAFF AS OF JUNE 30, 1969

Washington Boulder Total

Full-time permanent staff ^ 2, 867 566 3, 433 Other staff 2 502 68 570

Total paid staff 3, 369 634 4, 003 Research associates and guest workers 135 15 150 Total NBS staff 3, 504 649 4, 153

Professional staff with academic degrees

:

Physicists 401 114 515 Chemists 263 6 269

Engineers _ __ _ _ 181 82 263 Mathematicians _ _ _ _ 47 4 51 Other 130 7 137 Total 1, 022 213 1, 235

1 Includes Post Doctoral Research Fellows.

2 Summer, Youth Opportunity Corps, Part-time, Intermittent and Temporary. FINANCIAL DATA FOR FISCAL YEAR 1969

Program and source of financing

Supported by NBS Appropriations

Operating programs

:

Research and technical services Civilian industrial technology

Special foreign currency program

Construction and facilities programs

:

Plant and facilities Construction and facilities Total obligations, NBS appropriations 42, 273 Supported by other funds : ^ From other Federal agencies 24, 960 From other sources 4, 073 Total obligations, other funds 29, 033 Total program 71, 306

1 Work supported by other funds consists of research and development programs for other Government agencies ; consultative, advisory, and technical services, the performance of various tests and calibrations, and the manufacture and sale of standard reference mterials

for other Government agencies and the public. RESEARCH ASSOCIATES AND GUEST WORKERS

Research Associates and Their Sponsors

During Fiscal Year 1969

American Dental Association Argentar, Mr. Harold

Bowen, Mrs. Joy C. Bowen, Dr. Rafael L. Brown, Dr. Walter E, Brunetti, Dr. Anthony P.

Obligations incurred in thousands

of dollars (rounded) - $36,10039

900

._ 2, 441 - 2, 793

188
Carlson, Mr. Elmer T. Caul, Mr. Harold J. Chandler, Mr. Harry H.

Gregory, Mr. Thomas M., Jr. Kinsbury, Mrs. Pamela

Mable, Mr. Curtis P., Jr. Manuszewski, Mr. Richard C. McDowell, Mr. Hershel

Moreno, Dr. Edgard C. Paffenbarger, Dr. George C. Palcic, Miss Julia M.

Patel, Mr. Praful Rupp, Dr. Nelson Woodward

Wallace, Mrs. Betty M.

Waterstrat, Mr. Richard M. AmericiM Electroplaters Society

Johnson, Mr. Christian E. American Society for Testing and Materials

Bell, Mrs. Jacqueline T. de Groot, Mr. Johan H.

Evans, Mrs. Eloise H.

Grimes, Mr. John W., Jr. McMurdie, Mr. Howard F. Morris, Mrs. Marlene C. American Society for Testing and Materials (Concrete and Concrete Reference

Laboratory)

Anderson, Mr. Harry G., Jr. Atkinson, Mr. George O., Jr. Dise, Mr. John R. Johnson, Mr. Marlin C. Katz, Mrs. Anne K.

Liskey, Mr. John F. McCarthy, Mr. Dennis D.

Spring, Mr. Curtis B. Sturm, Mr. William F. Wallace, Mr. Dennis R. American Viscose Division (FMC Corporation)

Oneal, Mr. Glen, Jr. Bell Aerosystems

Rogers, Ernest E. Children's Hospital

Borasky, Dr. Rubin

Consumers Union of U.S., Inc. Kanagy, Dr. Joseph R. Control Data Corporation

Buckland, Mr. Stanley, F., Jr. Corn Refiners Association, Inc. Thomas, Mr. James H. Vomhof, Dr. Daniel W.

Corning Glass Worlds

Justice, Mr. Benjamin

Dow Chemical Company

Hamilton, Mr. Robert M. Eastman Kodak Company

Prsybylowicz. Dr. Edwin P.

189
Elect7'ical Testing Loboratories, Inc. Mohan, Mr. Kshitij

Factory Mutual Researcli Corporation

Kappraff, Mr. Ronald M.

Orloff, Mr. Lrawrence

Rockett. Dr. John A. Torrance, Dr. Kenneth E. International Business Machines Corporation

Cleveland, Mr. Nonnan G.

Phillips, Dr. Sidney L. Japan Electronic Industry Development Association Yamadori, Mr. Yuji Kennecott Copper Corporation

Harvey, W. "William Manufacturing Chemists Association

Clark, Mr. Joseph E. GiU, Paul C. Herndon, Mr. John L., Ill

Slater, James Alan

Martin Marietta Corporation (Research Institute for Advanced Studies)

Mengenberg, Dr. Hans-Dieter

Nippon Electric Company (Japan)

Inawashiro, Mr. Tutomu

Oioens-Coming Fiherglas Corporation

Fitch, Mr. William E. Porcelain Enamel Institute Burdick, Mr. Milton D. Baker, Mrs. Margaret A.

Gugeiler, Mr. Lauren A. State of Maryland

Benjamin, Arthur

Underwriters Laboratories, Inc. Castino, Mr. Guy T. U.S. Navy Marine Engineering Laljoratory

Arora, Dr. Om P. U.S. Naval Ship Research d Development Center Hammond, Barry L. U.S. Steel Corporation

Martin, Mr. John F. Swartz, John C. ADVISORY COMMITTEES

STATUTORY VISITING COMMITTEE

The Statutory Visiting Committee was established by Act of Congress to advise the Secretary of Commerce and the Director of NBS. This committee is ap- pointed by the Secretary of Commerce. It meets at the call of its chairman. Dates

indicate expiration of appointment.

Dr. Robert L. Sproull, Vice President, University of Rochester (1971),

Chairman

Prof. Norman F. Ramsey, Dept. of Physics, Harvard University (1970)

190
Dr. E. R. Piore, Vice President & Chief Scientist, International, Business

Machines Corporation (1972)

Dr. Elmer W. Engstrom, President, Radio Corporation of America (1973)

Dr. J. E. Goldman, Senior Vice President, Research & Development, Xerox

Corporation (1974)

TECHNICAL ADVISORY PANELS

The panels advisory to the National Bureau of Standards were established in 1959 under the terms of a contract between the National Bureau of Standards

and the National Academy of Sciences. The Advisory Panels are responsible to the National Academy of Sciences-National Academy of Eng-ineering-Nationa,l

Research Council, Division of Physical Sciences. One panel is established for each of the three Institutes of the Bureau, and one panel for each of the major

divisions within the Institutes. The advisory panels to the Institute for Applied

Technology are appointed by the President of the National Academy of Engineering. A1.1 other panels are appointed by the President of the National Academy

of Sciences. The divisional panels ordinarily have eight members although by

special arrangement a few have more or less. Terms are usually three years.

Institute for Basic Standards

Advisory Panel to Institute for Basic Standards

Dr. William G. Amey, Leeds & Northrup Company

Dr. John A. Hornbeck, Sandia Corporation

Prof. John Todd, California Institute of Technology

Mr. Eric J. Schneider, Engis Equipment Company

Prof. S. R. Beitler, American Society of Mechanical Engineering

Dr. E. F. Hammel, University of California Dr. Wade L. Fite, University of Pittsburgh

Prof. Sanborn C. Brown, Massachusetts Institute of Technology

Dr. Paul D. Coleman, University of Illinois Mr. Nathan Cohn, Leeds and Northrup Company

Prof. Robert Novick, Columbia University

Dr. Clyde McKinley, Air Products and Chemicals, Inc. Advisory Panel to Applied Mathematics Division

Prof. John Todd, Chairman California Institute of Technology

Prof. Francis J. Anscombe, Yale University

Prof. Philip J. Davis, Brown University

Prof. Charles R. DePrima, California Institute of Technology

Prof. H. O. Hartley, Texas A. & M. University

Prof. M. H. Martin, University of Maryland

Prof. Marvin L. Minsky, Massachusetts Institute of Technology

Prof. John Riordan, The Rockefeller University

Advisory Panel to Electricity D ivision Dr. William G. Amey, Leeds & Northrup Company, Chairman

Prof. Raymond M. Fuoss, Yale University

Prof. H. N. Hayward, University of Illinois Mr. William J. Johnson, Philadelphia Electric Company

Prof. George B. Hoadley, North Carolina State University

Dean R. B. Lindsay, Brown University Mr. S. C. Richardson, General Electric Company

Mr. Douglas C. Strain, Electro Scientific Industries, Inc. Advisory Panel to Metrology Division Mr. Eric J. Schneider, Engis Equipment Company, Chairman

Prof. Isay A. Balinkin, University of Cincinnati Mr. B. R. Buus, General Electric Gonipaiiy Dr. Alsoph H. Corwin, The .Tolins Hopkins I'liiversity Mr. J. K. Emery, The Van Keurcii ('(uiiitaiiy Dr. Robert E. Hopkins, University ot Rochester 191
Mr. Louis Polk, Dayton, Ohio

Dr. George J. Zissis, University of Michigan

Advisory Panel to MecJianics Division

Prof. S. R. Beitler, American Society of Mechanical Engineering, Chairman

Prof. Lynn S. Beedle, Lehigh University

Dr. B. B. Dayton, The Bendix Corporation

Prof. Cyril M. Harris, Columbia University

Dr. Arthur T. Ippen, ISIassachusetts Institute of Technology

Dr. Harry F. Olson, RCA Laboratories

Prof. R. S. Rivlin, Lehigh University

Dr. M. E. Shank, Pratt & Whitney Aircraft Advisory Panel to Heat Division

Dr. E. F. Hammel, University of California, Chairman

Prof. G. B. Benedek, Massachusetts Institute of Technology

Prof. John E. Kilpatrick, Rice University

Dr. James E. Mercereau, California Institute of Technology

Dr. John P. McCullough, Mobil Oil Corporation

Dr. James W. Moyer, Northrop Corporation.

Prof. John G. Phillips, University of California

Prof. Howard Reiss, University of California Advisory Panel to Atomic and Molecular Physics Division

Dr. Wade L. Fite, University of Pittsburgh, Chairman

Prof. C. O. Alley, University of Maryland

Dr. James E. Drummond, Boeing Scientific Laboratories

Prof. Vernon W. Hughes, Yale University

Prof. Richard C. Lord, Massachusetts Institute of Technology

Prof. Robert Novick, Columbia University

Prof. W. E. Spicer, Stanford University

Prof. George Wallerstein. University of Washington

Advisory Panel to Radio Standards Physics Division

Prof. Sanborn C. Brown, Massachusetts Institute of Technology, Chairman

Dr. George Birnbaum, North American Aviation Science Center

Dr. Arnold L. Bloom, Spectra-Physics

Prof. A. Javan, Massachusetts Institute of Technology

Dr. Josua Menkes. Institute for Defense Analyses

Dr. Robert W. Terhune, Ford Motor Company

Advisory Panel to Radio Standards Engineering Division

Dr. Paul D. Coleman, University of Illinois, Chairman

Mr. Stuart L. Bailey, Atlantic Research Corporation Mr. Ray Bailey, Newark Air Force Station

Prof. Herbert J. Carlin, Cornell University

Dr. Archie Gold, Army Ballistic Defense Agency

Mr. Theodore S. Saad, Sage Laboratories, Inc. Mr. C. E. White, AVCO Corporation

Advisory Panel to Time and Frequency Division Mr. Nathan Cohn, Leeds and Northrup Company, Chairman

Dr. L. S. Cutler, Hewlett-Packard Company

Dr. John M. Holt, Research Mathematics Group

Mr. Chesley Looney, National Aeronautics and Space Admin,

Dr. A. O. McCoubrey, Varian Associates

Dr. J. A. Pierce. Harvard University

Dr. Gemot M. R. Winkler, U.S. Naval Observatory

Advisory Panel to Laboratory Astrophysics Division

Prof. Robert Novick, Columbia University, Chairman

Dr. .James E. Drummond, Boeing Scientific Research Laboratories

Dr. John W. Evans, Air Force Cambridge Research Laboratory

Prof. Ronald Geballe, University of Washington

Dr. Wayland C. Griffith, Lockheed Missiles & Space Company

Dr, George H. Herbig, University of California 192
Prof. Dudley Herschbach, Harvard University

Dr. John A. Hornbeck, Sandia Corporation

Prof. Robert P. Kraft, University of California Advisory Panel to Cryogenics Division

Dr. Clyde McKinley, Chairman Allentown Laboratories

Dr. Frederick J. Edeskuty, Los Alamos Scientific Laboratory

Dr. Alan M. Lovelace, Air Force Materials Laboratory

Dr. William R. Lucas, National Aeronautics and Space Administratit Dr. John L. Mason, AiResearch Manufacturing Company

Dr. J. V. Sengers, University of Maryland

Advisory Panel to Institute for Materials Research

Dr. William P. Slichter, Bell Telephone Laboratories

Dr. William O. Baker, Bell Telephone Laboratories

Prof, John Bardeen, University of Illinois Dr. Arthur Bueche, General Electric Research Laboratory

Prof. L. B. Rogers, Purdue University

Prof. Walter H. Stockmayer, Dartmouth College Dr. J. H. Crawford, University of North Carolina

Prof. John E. Willard, University of Wisconsin

Advisory Panel to Analytical Chemistry Division

Prof. L. B. Rogers, Purdue University, Chairman

Prof. Walter J, Blaedel, University of Wisconsin

Dr. T. S. Burkhalter, Texas Instrument Company

Mr. M. D. Cooper, General Motors Corporation

Dr. John F. Flagg, American Cyanamid Company

Dr. Vincent P. Guinn, Gulf General Atomic, Inc. Dr. N. B. Hannay, Bell Telephone Laboratories

Prof. Sidney Siggia, University of Massachusetts

Dr. Ralph E. Thiers, Bio Science Laboratories

Advisory Panel to Polymers Division

Prof. Walter H. Stockmayer, Dartmouth College, Chairman

Dr. Raymond F. Boyer, Dow Chemical Company

Dr. Frederick J. Fowkes, Lehigh University

Dr. Fred Leonard, Walter Reed Army Medical Center

Prof. Carl S. Marvel, University of Arizona

Dr. Eraser P. Price, University of Massachusetts

Prof. Duane F. Taylor, University of North Carolina

Prof. Bruno H. Zimm, University of California Advisory Panel to Metallurgy Division

Dr. Walter A. Dean, Aluminum Company of America

Dr. G. J. Dienes, Brookhaven National Laboratory

Dr. Julius J. Harwood, Ford Motor Company

Dr. Richard A. Oriani, United States Steel Corporation

Dr. Robb M. Thomson, State University of New York

Prof. David Turnbull, Harvard University

Dr. H. G. F. Wilsdorf, University of Virginia

Advisory Panel to Inorganic Materials Division

Dr. J. H. Crawford, University of North Carolina, Chairman

Dr. George J. Bair, Corning Glass Works

Dr. Theodore L. Brown, University of Illinois Dr. Harris M. Burte, Air Force Materials Laboratory

Prof. Clyde A. Hutchison, Jr., The University of Chicago

Dr. J. S. Kasper, The General Electric Company

Prof. John L. Margrave, Rice University

Prof. Alan M. Portis, University of California Dr. Elias Snitzer, American Optical Company

Prof. J. H. Van Vleck, Harvard University

Advisory Panel to Physical Chemistry Division

Prof. John E. Willard, University of Wisconsin, Chairman

193
Professor Kyle D. Bayes, University of California Dr. Hartwell F. Calcote, AeroChem Research Laboratories, Inc. Dr. F. G. Ciapetta, W. R. Grace & Company

Dr. R. E. Fox, Westinghouse Electric Corporation

Prof. B. S. Rabinovitcli, University of Washington

Prof. T. N. Rhodin, Cornell University

Dr. Bruno J. Zwolinski, Texas A. & M. University

Advisory Panel to Institute for Applied Technology

Mr. Kenneth C. Allen, Hobart Manufacturing Company

Dr. Robert A. Hechtman, McLean, Virginia Dr. Leon Podolsky, Pittsfield, Massachusetts

Prof. Philip Morse, Massachusetts Institute of Technology

Dr. Jack Moshman, LEASCO Systems & Research Corporation

Dr. W. J. Harris, Jr., Battelle Memorial Institute Dr. Carl H. Madden, U.S. Chamber of Commerce

Dean Joseph R. Passonneau, Skidmore, Owens & Merrith

Mr. Jacob Rabinow, Bethesda, Maryland

Mr. Paul Strassmann, National Dairy Products Corporation Mr. Michael Witunski, McDonnell Douglas Corporation

Advisory Panel to Building Research D ivision Dr. Robert A. Hechtman, McLean, Virginia, Chairman

Prof. Ray Clough, University of California Mr. Edward N. Davis, Underwriters Laboratories, Inc. Dr. J. Vincent Fitzgerald, Tile Council of America, Inc. Dr. William H. Lindsay, Jr., Mechanical Contractors Association of Philadelphia, Inc. Mr. Andrew R. Lolli, State Department of General Services Mr. Raymond C. Reese, Toledo, Ohio

Dean Charles E. Schaffner, Polytechnic Institute of Brooklyn

Dr. J. A. Stavrolakis, American Standard

Mr. Herbert H. Swinburne, Nolan, Swinburne & Associates Mr. Charles H. Topping, E. I. DuPont de Nemours & Company

Advisory Panel to Electronic Technology Division

Dr. Leon Podolsky, Pittsfield, Massachusetts, Chairman

Mr. J. A. Caffiaux, Electronic Industries Association Mr. Ralph E. Clarridge, IBM Corporation Mr. Ivan G. Easton, General Radio Company

Mr. H. J. Luer, Bell Telephone Laboratories Mr. Peter R. Perino, Statham Instruments, Inc. Dr. Robert Pritchard, Stanford University Mr. Robert I. Scace, General Electric Company

Mr. Samuel H. Watson, Radio Corporation of America

Dr. Richard C. Webb, Colorado Instruments, Inc. Advisory Panel to Technical Analysis Division

Prof. Philip Morse, Massachusetts Institute of Technology, Cliairinnii Prof. George B. Dantzig, Stanford University Mr. Leslie C. Edie, The Port of New York Authority

Mr. Martin L. Ernst, Arthur D. Little, Inc. Mr. David B. Hertz, McKinsey and Company, Inc. Dr. William Linvill, Stanford University

Dr. Hugh J. Miser, Hartford, Connecticut

Prof. Thornton L. Page, Houston, Texas

Dr. George Pettee, Research Analysis Corporation

Prof. Gustave J. Rath, Northwestern University Mr. Robert H. Shatz, United Aircraft Advisory Panel to Center for Coinputer Sciences and Technology

Dr. Jack Moshman, LEASCO Systems & Research Corporation, Chairman

Mr. H. G. Asmus, American Federation of Information Processing Societies Mr. T. E. Climis, IBM Corporation

194
Dr. William W. Eaton, WasMngton, D.O. Mr Elmer C. Kubie, Computer Company, Inc. Mr. J. Don Madden, Association for Computing Machinery

Dr. Alan J. Rowe University of Southern California Mr. F. Gordon Smith, Business Supplies Corporation of America

Dr. Willis H. Ware, The RAND Corporation A dvisory Panel to Center for Radiation Research

Dr. Marshall R. Cleland, Chairman, Radiation Dynamics, Inc. Dr. S. C. Abrahams, Bell Telephone Laboratories

Dr. Peter T. Demos, Massachusetts Institute of Technology

Dr. R. B. Leachman, Kansas State University

Prof. E. W. Montroll, University of Rochester

Dr. Charles J. Mullin, University of Notre Dame

Dr. George F. Pieper, National Aeronautics and Space Admin.

Dr. W. C. Roesch, Battelle-Northwest

Prof. Erwin F. Schrader, Case Institute of Technology

Prof. C. G. Shull, Massachusetts Institute of Technology

AWARDS AND HONORS

Recognition of the Bureau's contributions to science and technology often takes the form of awards and honors from Government, academic, professional,

and industrial groups. The following list reflects such recognition bestowed on Bureau staff members during fiscal year 1969. Recipient

Astin, Allen V.

Bates, Roger G. Bennett, John

Branscomb, Lewis M.

Brauer, Gerhard M.

Foster, Bruce E.

.Tacox, Marilyn E. Lloyd, Edward C.

Lonnie, Mansfield (retired)

Marton, Ladislaus L.

Meinke, W. Wayne

Meyerson, Melvin R. MLUigan, Dolphus E. Napolitano, Albert

Award

Elected Honorary Member, American Society

of Heating, Refrigerating and Air Condition- ing Engineers

Elected Member, National Academy of Public Administration

American Chemical Society Award in Analytical Chemistry

George Kimball Burgess Award, Washington

Chapter of American Society for Metals Career Service Award, National Civil Service League

Souder Award of the International Association

for Dental Research

Henry L. Kennedy Award of American Concrete Institute Frank E. Richart Award, American Society for Testing and Materials

Recognition Award, Washington Academy of Sciences Awarded Fellow Member Certificate by Washington Section, American Society of Mechanical Engineers

Awarded Plaque from Mail Order Association

of America for work on standards of cloth- ing sizes Elected Fellow, Institute of Electrical and

Electronics Engineers

Honorary Membership, Electron Probe Analysis Society of America

George von Hevosy Award, Journal of Radioanalytical Chemistry

Special Award from American Nuclear Society Elected Honorary Member, Society Analytical

Chemistiy, (Ivv.it Britain Burgess Mcniori.il Award, Washington Cliapter, Ain(M'i( an Society of Metals

Recognition Award, Washington Academy of Sciences Elected Fellow, American Ceramic Society

195
Paflfenbarger, George C.

Parsons, Douglas E. (retired) Ta3dor, John K.

Wildhack, William A. Williams, Morgan L. Burdick, Milton D.

Coriell, Sam R.

Currie, Lloyd A.

Dibeler, Vernon H.

Franklin, Alan D. Hamer, Walter J. Isbell, Horace S. LaFleur, Philip D. Meinke, W. Wayne

Pope, Chester I. Scribner, Bourdon F. Sorrows, Howard E.

Steiner, Bruce W.

Gold Medal, Pierre Fouchard Academy

Elected Honorary Fellow, International

College of Dentists Distinguished Service Award, Underwriters'

Laboratories, Inc. Awarded Honor Scroll, Washington Chapter, American Institute of Chemists

Honorary Membership, Instrument Society

of America

District Meritorious Certificate Award by

American Welding Society

Elected Fellow, Washington Chapter of the American Institute of Chemists

EUGENE C. CRITTENDEN AWARD

(National Bureau of Standards)

For superior performance by support personnel.

Recipient Area

Hester, James Electrical services Hydro, John, Jr. Glassblowing

Lantz, Herman L. Floor care

Lederer, G-race S. Procurement services Mayers, Susan B. Cleaning services

Micha,lak, John L. Structural testing

Pittman, Arthur, Jr. Payroll problems

Schneider, Lawrence Precision instruments

SAMUEL WESLEY STRATTON AWARD

(National Bureau of Standards)

For outstanding scientific engineering achievements in support of the NBS

mission. David R. Lide, Jr. EDWARD BENNETT ROSA AWARD

(National Bureau of Standards)

For outstanding achievement in the development of standards of practice, the standards by which industry judges its operations, its production processes, and the quality of its products.

W. Wayne Meinke

196
DEPARTMENT OF COMMERCE EXCEPTIONAL

SERVICE AWARDS

(Gold Medal)

Recipient

Costrell, Louis

Kostkowski, Henry J. Kushner, Lawrence M.

Lide, David R., Jr. Shuler, Kurt E. Group Award

:

Muehlhause, Carl O. Landon, Harry H., Jr. Carter, Robert S.

Technical Area

Radiation Physics Instrumentation

Radiation Thermometry

Research Management

Molecular Structure Chemical Physics

Nuclear Radiation

DEPARTMENT OF COMMERCE MERITORIOUS

SERVICE AWARDS

(Silver Medal)

Recipient

Allen, David W.

Coates, Clarence N., Jr. Cullen, William C. Cuthill, John R. DeVoe, James R.

Garfinkel, Samuel B. Heinrich, Kurt F. J. McCrackin, Frank L. Marshak, Harvey

Martin, William C, Jr. Oser, Hans J. Schooley, James F.

Tilley, William R. Walton, William W.

Weiss, Andrew W.

WoUin, Harold F. Joint Award

:

Shields, William R. Murphy, Thomas J.

Technical Area

Atomic Frequency and Time Standards

Legislative Programs

Materials Durability

Alloy Physics

Radiochemical Analysis

Radioactivity Standards

X-ray Spectrometry

Ellipsometry

Cryogenic Physics

Atomic Spectroscopy

Systems Dynamics

Cryogenic Physics

Technical Information

Building Research

Plasma Spectroscopy

Weights and Measures

Analytical Mass Spectrometry

DEPARTMENT OF COMMERCE SUPERIOR

SERVICE AWARDS

(Bronze Medal)

Recipient

David, Richard M.

Garing, Herbert H.

Henley, Elizabeth L. M.

Ledford, Albert E., Jr. Lunsford, Katherine S. Massie, Minnie R. Missimer, Joshua K.

Pearson, Cornelius H.

Peterson, Ruth L. Roberts, Marion S. Snyder, Wilbert F. Williams, Earl S.

Technical Area

Radiation Chemistry

Instrument Shops

Administrative Issuance Systems

Molecular Energy Levels Thermometer Calibration Thermometer Calibration Fibrous Systems

';rh (

' 1- ni (

) p b y si ( -al Properties

Spccti-oscopy

Employee ])evelopment and Relations Radio Standards Fiiigiiieering Elect rical Instruments

197
EDUCATION, TRAINING, AND UNIVERSITY LIAISON

A comprehensive employee development program, ranging from broad surv^eys

to very detailed treatment of a new or specialized area of research, is available

to all staff members and to members of other Government agencies and industrial personnel on a space-available basis. Courses and seminars are implemented

primarily through the NBS Graduate School and special educational programs

for subprofessional and non-professional employees, through non-Government

educational and training facilities, and through interagency offerings. The

programs range from adult basic education through postdoctoral research, and

are offered at both the Boulder and Gaithersburg Laboratories. The primary

objectives are to increase employee knowledge, skills, and efficiency in assigned

duties in the categories more fully described below, and to prepare Bureau staff members to respond to the rapidly changing technology at all levels. Programs

also include emphasis on maintaining liaison with the public, industry, commerce, and science. In accord with Federal policy the Bureau is increasing its participation in projects aimed at stimulating community interest. Instruction by our scientists in the fields of their expertise, and facilities are being made available to the

universities, public schools, professional societies, and the indu'=^trial and scientific community. In addition to numerous seminars offered through the Graduate

School program and in cooperation with other Government and industrial agencies at the division and institute levels, there is the weekly National Bureau

of Standards Scientific Colloquium at which current topics of broad interest to the Bureau are presented. These are open to the public and are attended by

members of the university, industrial and Government communities, as well as by NBS personnel. Speakers are drawn from the outside community and from

the NBS staff. Monthly colloquia under the joint sponsorship of the National

Institutes of Health and the National Bureau of Standards are also offered, with each institution alternating as host. NBS Graduate School

The NBS Graduate School curriculum includes graduate and undergraduate

courses in the physical sciences, mathematics and specialized branches of engineering. A series of scientific colloquia and seminars designed to update and

continue the education of the postdoctoral scientist are led by research leaders from the Bureau and from other research centers and universities. In addition,

general staff development courses are offered, such as Supervision and Management, Reading Improvement. Technical Report Writing, and administrative and clerical conferences, workshops, and courses. Two special programs, designed for technicians and subprofessional laboratory

personnel, offer courses both in-house and in cooperation with the Montgomery

Junior College leading to two NBS Technician Certificates and/or the A. A. degree at the Montgomery Junior College. Surveys periodically redetermine

course offerings and keep the program in step with the changes and variations

in educational requirements and the changing technology. Graduate degrees

based partly on credit obtained for courses or thesis research carried on under

the NBS Graduate School Program have been earned by 2 Bureau employees

this year, bringing the total to 350 sraduate degrees earned at 45 different universities since the establishment of the educational program in 1908. The Graduate School at Boulder is associated with the University of Colorado

in a Joint-Course program and Adjunct Professor Plan. Various graduate depart- ments of the NBS Graduate School at Boulder and the University offer courses which mutually benefit the Government and the University.

Postdoctoral Research Associateships

The National Bureau of Standards, in cooperation with the National Research Council, National Academy of Sciences-National Academy of Engineering, offers a number of awards for postdoctoral research. These awards provide young scientists of unusual ability and promise an

opportunity for fundamental research in various branches of the physical, engineering, and mathematical sciences. Applications are evaluated by a Board of

Selection appointed by the National Research Council. The NRC-NBS Post- doctoral Research Associateship program has been in existence since 1954. There have been 187 awards made during these years. 198
Postdoctoral Research Associates on Duty During Fiscal Year 1969

Name

Alderman, Donald W.

Bielefeld, Michael J. Borie, Edith F.

Cahill, Kevin E. Davis, Douglas

DeLancey, George B, Denenstein, Arnold M.

Duerst, Richard W.

Ensign, Thomas C. Epstein, Gabriel L. Fickett, Frederick R.

Gibson, Benjamin F. Golub, Stephen

Greenhouse, Jeffrey A.

Handj'^, Larry B. Hegstrom, Roger A. Hoegy, Walter R. Knoeck, John W.

Latanision, Ronald M.

Ledbetter, Hassell M.

Ott, William R.

Parke, William C.

Pierce, Stephen J. Plummer, Earl W.

Ponzini, Robert G. Raveche, Harold J. Searles, Stuart K.

Shirk, James S. Stokowski, Stanley E.

Sullivan, Donald B. Thornton, Donald D. Weisman, Irwin I. Williams, H. T. Zalewski, E. F.

University Cornell University U. of Pennsylvania

U. of North Carolina

Harvard University U. of Florida U. of Pittsburgh U. of Pennsylvania U. of California (Berkeley) U. of Wyoming

U. of California (BerkelejO

Oregon State University Stanford University

Columbia University U. of California (Berkeley) U. of Wisconsin

Harvard University U. of Michigan Iowa State University

Ohio State University U. of Illinois U. of Pittsburgh

George Washington University^ U. of Calif. (Santa Barbara)

Cornell University

Michigna State University U. of California (LaJolla) U. of Alberta (Canada) U. of California (Berkeley) Stanford University

Vanderbilt University^

Syracuse University U. of California (Berkeley) U. of Virginia U. of Chicago

NB8 Adviser R. J. Mahler

J. J. Spijkerman

L. C. Maximon

S. Meshkov

H. Okabe

H. Oser

F. K. Harris G. F. Kokoszka

T. Chang

J. Reader

R. Powell M. DanOS B. Steiner W. J. Lafferty

F. E. Brinckman

J. H. Shirley R. Mountain

J. K. Taylor

A. W. Ruff

R. P. Reed

W. Wiese

R. W. Hayward

M. Newman

R. D. Young

S. Meshkov

R. Mountain

P. Ausloos

A. M. Bass

L. H. Grabner

R. A. Kamper

B. M. Mangum

L. H. Bennett M. Danos

R. A. Keller Other Employee Development Programs

In addition to the programs for technicians described above, the National Bureau of Standards recognizes the need to develop and upgrade the nonprofessional staff, which plays an essential role in the support of the scientific

staff. Therefore, courses in adult basic education are offered in cooperation with

the Montgomery County Public Schools, designed to help the individual in his work. Also, foreign-born individuals who need improvement in oral and written English can enroll in classes being taught by experienced adult teachers who are aware of the problems facing the non-English speaking individual. Non-Government Education

Non-Government education falls into three categories . . . full-time (3 to 12 months) graduate study and research assignments at universities and research

centers; full-time (less than 3 months) attendance at iiistitnlcs, sciuiiiars. short concentrated courses and workshops; and part-time, job-related acadcMiiic courses

at universities and in industry. In the last year 054 staff members at Washington

and Boulder were trained through non-Government facilities, and (> career employee were selected for full-time graduate study or research assignments

at universities and research centers. Participants in approved full-time train- ing programs receive full salary and expenses, including tuition, fees, travel, and per diem, as well as transportation of family and household effects. In

addition, 648 staff members, mostly from technical divisions, attended job- related courses on a semester basis, and shorter concentrated courses at universities and in industry.

199
Interagency Training

Courses made available through the Interagency Training Programs are an

additional effective means of improving program operations for NBS personnel. Courses are offered at Government facilities in Supervision, Management, Office Skills and Practices, and specialized programs. This pooling of agency resources

offers broader employee development opportunities at a saving to the Government. During 1968, 230 National Bureau of Standards employees took advantage of the interagency offerings.

PUBLICATIONS*

PUBLICATIONS IN THE BUREAU'S SERIES

During the year NBS publications totaled 1058 published papers

and documents.

Of the formal publications, 98 appeared in the Journal of Research,

and 676 in the journals of professional and scientific societies. Also,

172 summary articles were presented in the Bureau's Teclmical News

BuUetm.

In the non-periodical series, 112 documents were published: 8 in

the Monograph series, 2 in the Handbook series, 28 in the Special Publication series, 6 in the Building Science series, 50 in the Technical Note

series, 7 m the National Standard Reference Data Series, 1 in the Applied Mathematics series, 9 in the Federal Information Processing

Standard series, and 1 in the Product Standards series. Journal of Research. Reports National Bureau of Standards research and devel- opment in physics, mathematics, chemistry, and engineering. Comprehensive

scientific papers give complete details of the work, including laboratory data,

experimental procedures, and theoretical and mathematical analyses. Illus- trated with photographs, drawings, and charts. Section A. Physics and Chemistry. Issued six times a year. Annual subscription

:

Domestic, $9.50 ; foreign, $11.75. Single copy price varies. SD Catalog No. C13.22/sec.A :74. Section B. Mathematical Sciences. Issued quarterly. Annual subscription: Domestic, $5 ; foreign, $6.25. Single copy, $1.25. SD Catalog No. C13.22/sec.B :74. Section C. Engineering and Pnstrumentation. Issued quarterly. Annual subscription : Domestic, $5 ; foreign, $6.25. Single copy, $1.25. S.D. Catalog No. C13.22/

sec.C :74. Journal of Research

Section A. Physics and Chemistry

J. Res. Nat. Bur. Stand. (U.S.), 72A (Phys. and Chem.), No. 4 (July-August

1968)

Mass spectrometric study of photoionization. X. Hydrogen chloride and methyl

halides. Morris Krauss, James A. Walker, and Vernon H. Dibeler. The fourth and fifth spectra of vanadium (Viv and Vv). Laura Iglesias.

Variation of absorptance-curve shape with changes in pigment concentration. Gerald L. Howett.

Periodic acid, a novel oxidant of polycyclic aromatic hydrocarbons. Alexander J. Fatiadi. Publications for which a price is indicated are available by purchase from the Superin- tendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 (foreign postage, one-fourth additional). The NBS non-periodical series are also available from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Va. 22151. Heprints from outside journals and the NBS Journal of Research may often be obtained

directly from the authors. 200
A galvanic cell with a low emf-temperature coefficient. Gerald N. Roberts and

Walter J. Hamer.

Synthesis of cerite. Jun Ito. Tables of collision integrals for the {m, 6) potential function for 10 values of m. Max Klein and Francis Smith. Spectrum of relaxation times in GeO- glass. A. Napolitano and P. B. Macedo.

Resume of values of the Faraday. Walter J. Hamer.

J. Res. Nat. Bur. Stand. (U.S.), 72A (Phys. and Chem.), No. 5 (SeptemberOctober 1968).

Studies in bomb calorimetry. A new determination of the energy of combustion

of benzoic acid in terms of electrical units. K. L. Churney and G. T. Armstrong.

Effect of low pressures on the room temperature transitions of polytetrafluoroethylene. G. M. Martin and R. K. Eby.

Electrostatic potentials and their spatial derivatives about point defects in ionic crystals. Herbert S. Bennett.

Electric fields produced by a charge density in ionic crystals. Herbert S. Bennett. Mass spectrometric study of the photoionization of some fluorocarbons and

trifluoromethyl halides. Clemente Juan Noutary.

Infrared matrix spectra of lithium fluoride. Stanley Abramowitz, Nicolo Asquista,

and Ira W. Levin. Electronic transition moment integrals for first ionization of CO and the A-X

transition in CO^ Some limitations on the use of the r-centroid approximation.

Paul H. Krupenie and William Benesch. The configurations 3d^^4P in doubly ionized atoms of the iron group. C. Roth.

Electron impact excitation of hydrogen Lyman-a radiation. Robert L. Long, Jr., Donald M. Cox, and Stephen J. Smith.

J. Res. Nat. Bur. Stand. (U.S.), 72A (Phys. and Chem.), No. 6 (NovemberDecember 1968.

Interaction energy surfaces for Li(2^S) and Li(2-P) with H2 M. Krauss. Energy levels and classified lines in the first spectrum of technetium (Tci).

W. R. Bozman, C. H. Corliss, and J. L. Tech. The first spectrum of tungsten ( W i) . Donald D. Laun and C. H. Corliss. Theoretical interpretation of the even levels in the first spectrum of tungsten.

Y. Shadmi and E. Caspi. Stable carbon isotope ratio measurement with a gas density meter. S. P. Wasik

and W. Tsang.

The single crystal spectrum of hexakis( imidazole) nickel (II) nitrate. Curt W.

Reimann.

Crystalline alpha and beta forms of 3-0-a-D-glucopyranosyl-D-arabinopyranose. Horace S. Isbell, Harriet L. Frush, and J. D. Moyer.

Preparation and solubility of hydroxyapatite. E. C. Moreno, T. M. Gregory, and

W. E. Brown. High temperature dehydroxylation of apatitic phosphates. T. Negas and R. S. Roth.

J. Res. Nat. Bur. Stand, (U.S.), 73A (Phys. and Chem.), No. 1 (JanuaryFebruary 1969)

Specific heats of oxygen at coexistence. Robert D. Goodwin and Lloyd A. Weber.

Specific heats C„ of fluid oxygen from the triple point to 800 K at pressures

to 350 atmospheres. Robert D. Goodwin and Lloyd A. Weber.

Thermodynamic properties of fluid oxygen at temperatures to 250 K and pres- sures to 350 atmospheres on isochores at 1.3 to 3.0 times critical density.

Robert D. Goodwin.

Two new standards for the pH scale. Bert R. Staples and Roger G. Bates. Calculation of diffusion coefficients in ternary systems from diaphragm cell experiments. P. R. Patel, E. C. Moreno, and T. M. Gregory. Cnlculated line strength for the transition array {S(P-\-'M-4s)-3(mp in Tin.

H. Mendlowitz.

Morphological stability of a cylinder. Sam R. Coriell and Stephen C. Hnrdy.

Distorted tetahedra in strontium copper akermanite. Jun Ito and H. StelTen

Peiser. 201
Tritium-labeled compounds XII. Note on the synthesis of D-glucose-2-^ and

D-mannose-2-t Horace S. Ishell, Harriet L. Frush, C. W. R. AVade, and A. J. Fatiadi. A Survey of blemishes on processed microfilm. C. S. McCamy, S. R. Wiley, and

J. A. Speckman.

J. Res. Nat. Bur. Stand. (U.S.), 73A (Phys. and Chem.), No. 2 (March-April

1969)

Color representation of electron microprobe area-scan images by a color sepa- ration process. Harvey Yakowitz and Kurt F. J. Heinrich. Configurations 3<Z"4p in singly ionized atoms of the iron group. C. Roth.

Configurations 3(Z"4/)+3(Z""^4,S'4p in Sc ii, Ti ii, and V ii. C. Roth.

Effective interactions in the even configurations of the third spectra of the iron group. Y. Shadmi, E. Caspi, and J. Oreg. Test of a kinetics scheme : Emission in H S) +N0 II ) . M. Krauss. A nuclear magnetic resonance and relaxation study of dimethoxyborane. T. C. Farrar and T. Tsang.

The effects of low energy irradiation on organometallics. Organometal halides

of group IVA. F. E. Brinckman, Gerald F. Kokoszka, and Norman K. Adams.

Jr. Measurements of gaseous diffusion coefficients by a gas chromotographic

technique. S. P. Wasik and K. E. McCulloh. Phase relations in the Ru-Ir-O 2 system in air. C. L. McDaniel and S. J. Schneider. Heats of reaction of natural rubber with sulfur. Norman Bekkedahl and James

J. Weeks.

A tatole of rotational constants of symmetric top molecules giving rise to microwave spectra. Matthew S. Lojko and Yardley Beers. Energy levels, wave functions, dipole and quadrupole transitions of Fe "^"^"^ions in sapphire. Jacques Lewiner and Paul H. E. Meijer.

J. Res. Nat. Bur. Stand. (U.S.) 73A (Phys. and Chem.), No. 3 (May-June

1969)

New even levels and classified lines in the first spectrum of tungsten (W i) C. H. Corliss. The heat of combustion of beryllium in fiuorine. K. L. Churney, and G. T. Armstrong.

Deuterium isotope effect on the dissociation of w^eak acids in water and deuterium

oxide. R. A. Robinson, Maya Paabo, and Roger G. Bates, Vortex motions in ideal Bose superfluid. Martin J. Cooper.

Franck-Condon factors for the ionization of H2O and D2O. R. Botter and H. M.

Rosenstock.

Topological features of hot carrier induced anisotropic breakdown on silicon diode surfaces. George G. Harman.

The third spectrum of praseodymium (Pr. iii) in the vacuum ultraviolet. Jack

Sugar. Section B. Mathematical Sciences

J. Res. Nat. Bur. Stand. (U.S.), 72B (Math. Sci.), No. 3 (July-September 1968)

Interaction in multidimensional contingency tables : An information theoretic approach. H. H. Ku and S. Kullback. On the coupling of longitudinal and transverse waves in a linear three-element

viscoelastic string subjected to transverse impact. Jack C. Smith and Jeffrey

T. Fong.

Allocating service periods to minimize delay time. W. A. Horn. The second orthogonality conditions in the theory of proper and improver

rotations. I. Derivation of the conditions and of their main consequences. Harry Gelman.

Thickness and connectivity in graphs. Arthur M. Hobbs and J. W. Grossman.

J. Res. Nat. Bur. Stand. (U.S.), 72B (Math. Sci.), No. 4 (October-December

1968).

Principal submatrices VII : Further results concerning matrices with equal

principal minors. R. C. Thompson.

On the multipliers of the Dedekind modular function. Joseph Lehner. 202
Minimax error selection of a discrete univariate distribution with prescribed

componentwise bounds. A. J. Goldman and P. R. Meyers.

Minimax error selection of a discrete univariate distribution with prescribed

componentwise ranking. A. J. Goldman.

On the signs of the ?'-derivatives of the modified Bessel functions / (j?) and

K (a?), D. O. Reudink.

Comparison of finite-difference computations of natural convection. K. E. Torrance.

Generalized inverses and solutions of linear systems. John Z. Hearon.

J. Res. Nat. Bur. Stand. (U.S.), 73B (Math. Sci.), No. 1 (January-March

1969)

A table of integrals of the error functions. Edward W. Ng and Murray Geller. Fourier coefficients of Mathieu functions in stable regions. Henning Friichting.

A note on the T-transformation of Lubkin. W. D. Clark, H. L. Gray, and J. E. Adams.

The cylinder problem in tliermoviscoelasticity. Warren S. Edelstein. Relations within sequences of congruential pseudo-random numbers. Peter H.

Verdier. On the mean dimensions of restricted random walks. Peter H. Verdier and

Edmund A. DiMarzio.

The cube of every connected graph is 1-hamiltonian. Gary Chartrand and S. F. Kapoor.

Minimum-length covering by intersecting intervals. W. A. Horn.

J. Res. Nat. Bur. Stand. (U.S.), 73B (Math. Sci.), No. 2 (April-June 1969)

An evaluation of linear least squares computer programs. Roy H. Wampler.

The traffic assignment problem for a general network. Stella C. Dafermos and

Frederick T. Sparrow.

Sufficient conditions for the instability of numerical integration methods. Abbas J. Abdel Karim.

The second orthogonality conditions in the theory of proper and improper rotations. II. The intrinsic vector. Harry Gelman.

The second orthogonality conditions in the theory of proper and improper rotations. III. The conjugacy theorem. Harry Gelman.

Subgroups of SL{t,z). Morris Newman.

Cuttable and cut-reducible matrices. Rosalind B. Marimont.

Automorphic integrals with preassigned periods. Joseph Lehner. A digital computer technique for calculating the step response of lumped or

distributed networks. James R. Andrews and N. S. Nahman.

Symmetry and the crossing number for complete graphs. Thomas L. Saaty.

Section C. Engineering and Instrumentation

J. Res. Nat. Bur. Stand. (U.S.), 72C (Engr. and Instr.), No. 3 (July-September

1968)

Gas density balance design considerations. E. C. Creitz. Standard mismatch—the production of controlled small reflections in waveguides. L. Lewin.

Viscoelastic behavior of dental amalgam. P. L. Oglesby, G. Dickson, M. L. Rodriguez, R. M. Davenport, and W. T. Sweeney.

The steady-state creep behavior of dental amalgam. George Dickson, Philip

Oglesby, and Ruth Davenport.

J. Res. Nat. Bur. Stand. (U.S.), 72C (Engr. and Insir.), No. 4 (OctoberDecember 1968)

Theoretical and experimental study on longitudinal impact of lapered rods. L. R. Hettche. Analytical studies of probe conduction errors in ground tcnipci-al ur<' nicasun^- ments. B. A. Peavy.

Nonlinear constrained optimization by a nonrandom complex metliod R. A. Mitchell and K. L. Kaplan.

375-572—70 14 203
J. Res. Nat. Bur. Stand. (U.S.), 73C (Engr. and Instr.), Nos. 1 and 2 (JanuaryJune 1969)

An interferometer for measuring gradients in both refractive index and thickness

of large or small optics. J. B. Saunders. A Kerr electro-optical technique for observation and analysis of high-intensity

electric fields. Esther C. Cassidy and Harold N. Cones.

Student-^ deviate corresponding to a given normal deviate. Brian L. Joiner. A heat loss compensated calorimeter and related theorems. Steve R. Domen.

Laboratory measurements of air cavity temperature in a passenger car tire. B. G. Simson and J. Mandel.

Technical Neivs Bulletin. The best single source of information concerning

the Bureau's research, developmental, cooperative and publications activities, this monthly publication is designed for the industry-oriented individual whose

daily work involves intimate contact with science and technology—for engineers,

chemists, physicists, research managers, product-development managers, and com- pany executives. Readers use the TNB to learn of new developments with

practical applications, to fill in background, to get ideas for further investigations, and for information on NBS calibration services, publications, and conferences. Annual Subscription : Domestic, $3 ; foreign, $4. Single copy price 30

cents. Available on a 1-, 2-, or 3-year subscription basis. SD Catalog No. 013.13 :54. Monographs. Major contributions to the technical literature on various subjects

related to the Bureau's scientific and technical activities. Monogr. 25, Section 6. Standard x-ray diffraction powder patterns, Section 6.— Data for 60 substances, H. E. Swanson, H. F. McMurdie, M. C. Morris, and

E. H. Evans, Nat. Bur. Stand. (U.S.), Monogr. 25, Sec. 6, 101 pages (June

1968). 60 cents. Monogr. 70, Volume III. Microwave spectral tables. Volume III. Polyatomic molecules with internal rotation, P. F. Wacker, M. S. Cord, D. G. Burkhard, J. D.

Petersen, and R. P. Kukol, Nat. Bur. Stand. (U.S.), Monogr. 70, Vol. Ill, 275 pages (June 1969). $4.25. Monogr. 70, Volume IV. Microwave spectral tables. Volume IV. Polyatomic molecules without internal rotation, M S. Cord, J. D. Petersen, M. S. Lojko, and

R. H. Haas, Nat. Bur. Stand. (U.S.) , Monogr. 70, Vol. IV, 429 pages (Oct. 1968).

$5.50. Monogr. 70, Volume V. Microwave spectral tables. Volume V. Spectral line list- ing, M. S. Cord, M. S. Lojko, and J. D. Petersen, Nat. Bur. Stand. (U.S.), Monogr. 70, Vol. V, 538 pages (June 1968) . $4.75. Monogr. 105. Acid-based behavior in aprotic organic solvents, M. M. Davis, Nat. Bur. Stand. (U.S.), Monogr. 105, 156 pages (Aug. 1968). $2.25. Monogr. 107. Acceleration due to gravity at the National Bureau of Standards,

D. R. Tate, Nat. Bur. Stand. (U.S.), Monogr. 107, 24 pages (June 1968). 25

cents. Monogr. 109. Investigations of the exploding wire process as a source for high

temperature studies, E. C. Cassidy, S. Abramowitz, and C. W. Beckett, Nat. Bur. Stand. (U.S.), Monogr. 109, 53 pages (Nov. 1968). 55 cents. Monogr. 111. Technology of liquid helium, R. H. Kropschot, B. W. Birmingham,

and D. B. Mann, Editors, Nat. Bur. Stand. (U.S.), Monogr. Ill, 380 pages

(Oct. 1968). $2.00. Handbook, Recommended codes of engineering and industrial practice {including safety codes) developed in cooperation with interested industries, pro- fessional organizations, and regulatory bodies. In many cases the recommended

requirements are given oflicial status through their incorporation in local or- dinances by State and municipal regulatory bodies. H105-1. Specifications and tolerances for reference standards and field standard

weights and measures. 1. Specifications and tolerances for field standard

weights, T. M. Stabler, Editor, Nat. Bur. Stand. (U.S.), Handb. 105-1, 10 pages

(Apr. 1969). 25 cents. H106. CODASYL COBOL journal of development 1968, Nat. Bur. Stand. (U.S.), Handb. 106, 344 pages (July 1969). $2.75. 204
Special Publications. (Formerly Miscellaneous Publications) This series in- cludes proceedings of high-level national and international conferences sponsored

by NBS, precision measurement and calibration volumes, NBS Research Highlights, and other special publications appropriate to this grouping, such as administrative pamphlets, wall charts and bibliographies.

SP236, 1968 Edition. Services provided by NBS standard frequency stations WWV, WWVH, WWVB, and WWVL, Nat. Bur. Stand. (U.S.), Spec. Publ. 236, 15 pages (1968). (Supersedes Misc. Publ. 236, 1967 edition.) SP236, 1969 Edition. NBS frequency and time broadcast services, radio stations WWV, WWVH, WWVB, and WWVL, Nat. Bur. Stand. (U.S.), Spec. Publ. 236. 16 pages (1969). 25 cents. (Supersedes Spec. Publ. 236, 1968 edition.) SP260-16. Standard reference materials: homogeneity characterization of NBS

ispectrometric standards IV: preparation and microprobe characterization of W-20% Mo alloy fabricated by powder metallurgical methods, H. Yakowitz,

R. E. Michaelis, and D. L. Vieth, Nat. Bur. Stand. (U.S.), Publ. 260-16, 30 pages

(Jan. 1969). 35 cents. SP296. Mass transport in oxides. Proceedings of a symposium held at the National Bureau of Standards, Gaithersburg, Md., Octoher 22-25, 1967, J. B. Wachtman, Jr. and A. D. Franklin, Editors, Nat. Bur. Stand. (U.S.), Spec. Publ. 296, 224 pages (Aug. 1968) . $3.00. SP298. Quantitative electron probe microanalysis. Proceedings of a Seminar held

at the National Bureau of Standards, Gaithersburg, Md., June 12-13, 1967, K. F. J. Heinrich, Editor, Nat. Bur. Stand. (U.S.), Spec. Publ. 298, 305 pages

(Oct. 1968). $3.00. SP299, Volumes 1 and 2. Neutron cross sections and technology. Proceedings

of a conference held in Washington, D.C., March 4—7, 1988, D. T. Goldman,

Editor, Nat. Bur. Stand. (U.S.), Spec. Publ. 299, Vol. 1, 660 pages and Spec. Publ. 299, Vol. 2, 718 pages (Sept. 1968). $10.50 per set of 2 volumes. SP300, Volume 1, Precision measurement and calibration. Selected NBS papers on statistical concepts and procedures, H. H. Ku, Editor, Nat. Bur. Stand.

(U.S.), Spec. Publ. 300, Vol. 1, 436 pages (Feb. 1969). $5.50. SP300, Volume 2. Precision measurement and calibration temperatures. Selected NBS papers on temperature, J. F. Swindells, Editor, Nat. Bur. Stand. (U.S.), Spec. Publ. 300, Vol. 2, 520 pages (Aug. 1968). $4.75. SP300, Volume 3. Precision measurement and calibration. Selected NBS papers on electricity—low frequency, F. L. Hermach and R. F. Dziuba, Editors, Nat. Bur. Stand. (U.S.), Spec. Publ. 300, Vol. 3, 498 pages (Dec. 1968). $4.50.

( Supersedes in part Handbook 77, Vol. I.

)

SP301. Molecular dynamics and structure of solids. Proceedings of the Second

Materials Research Symposium held at the National Bureau of Standards,

Gaithersburg, Md., October 16-19, R. S. Carter and J. J. Rush, Editors, Nat. Bur. Stand. U.S.), Spec. Publ. 301, 580 pages (June 1969). $4.00. SP302. Thermal conductivity. Proceedings of the seventh conference held at the National Bureau of Standards, Gaithersburg, Md., November 13-16, 1967, D. R. Flynn and B. A. Peavy, Jr., Editors, Nat. Bur. Stand. (U.S.), Spec. Publ. 302, 820 pages (Sept. 1968). $6.25. SP303. Mechanical and thermal properties of ceramics. Proceedings of a sym- posium held at Gaithersburg, Md., April 1-2, 1968, J. B. Wachtman, Jr., Editor, Nat. Bur. Stand. (U.S.), Spec. Publ. 303, 275 pages (May 1969). $4.25. SP304. The modernized metric system—The International System of Units (SI), Nat. Bur. Stand. (U.S.), Spec. Publ. 304, 1 chart (1968). 50 cents. (Supersedes

Misc. Publ. 232.) SP304A. Brief history and use of the English and metric system of measurement, Nat. Bur. Stand. (U.S.), Spec. Publ. 304A, 4 pages (196S). 20 ctMits. SP305. Publications of the National Bureau of Standards 1966-15:67, P.. L. Oberholtzer, Nat. Bui. Stand. (U.S.), Spec. Publ. 305, 221 pages ( Ai)r. 19(5!)). $2.00. SP306-1. Bibliography on the analyses of optical atomic spectra. Section 1. ^H-'^V, C. E. Moore, Nat. Bur. Stand. (U.S.), Spec. I'ubl. 306-1, Sec. 1, 89 pages

( Sept. 1968). $1.00. SP306-2. Bibliography on the analyses of optical atomic spectra. Section 2. 2*Cr-*'Nb, C. E. Moore, Nat. Bur. Stand. (U.S.), Spec. I'ubl. .30(>-2, Sec. 2, <>3 pages (Feb. 1969). 60 cents. SP306-3. Bibliography on the anlyses of optical atomic spectra. Section 3. *^Mo-''La and ''Hf-'"Ac, C. E. Moore, Nat. Bur. Stand. (U.S.), Spec. Publ. 306-3,

Sec. 3, 37 pages (May 1969) . 50 cents. 205
SP307. Wolf-Rayet stars. Proceedings of a symposium lield at the Joint Institute for Laboratory Astrophysics. University of Colorado. Boulder. Colo.. June 10-

14, 196S, K. M. Grebbe and R. X. Thomas. Editors. Xat. Bur. Stand. (U.S.),

Spec. Publ. 370. 2S6 pages ( Dec. 196S i . .S3. 00. SP3(>S. Technical highlights of the National Bureau of Standards. Annual Report

Fiscal Year 1968, Xat. Bur. Stand. (U.S.). Siiec. Publ. 30^. 210 pases ( Xov. ims).

SP309, Volume 2. Computer literature bibliography 1964-1967, W. W. Youden.

Xat Bur. Stand. (U.S.), Spec. Publ. 309. Vol. 2, 3S5 pages (Dec. 196S). S5.00. SP310. Nuclear standards for chemistry and technology. Proceedings of a Symposimn on Standards in Nuclear Chemistry and Technology held at the 156th National Meeting of the American Chemical Society. Atlantic City. N..J., September S-9. 196S. H. F. Beeghly. J. P. Call, and W. ^y. Meinke. Editors, Nat. Bur. Stand. (U.S.). Spec. Publ. 310. 261 pages (Dec. 196S,). 81.25. SP311. Report of the 53d National Conference on Weights and Measures, 1968, R. L. Koeser, Editor. Nat. Btir. Stand. (U.S.), Spec. Publ. 311. 1S2 pages ( Mar.

1969). 81.25. SP312. Volumes I and II. Modern trends in activation analysis. Proceedings of the 1968 International Conference held at the National Bureau of Standards. Gaithersburg. Md.. October 7-11, 196S. J. P. DeVoe. Editor and P. D. LaFleur,

Assi-stant Editor. X'at. Bur. Stand. (U.S.). Spec. Ptibl. 312. Vol I, 691 pages and Vol. II. 676 pages ( June 1969 i. .SS.50 per set of 2 volumes.

SP313. Making valuable measurements. Proceedings of the 196S Standards Laboratory Conference. H. L. Mason. Editor, Xat. Bur. Stand. (U.S. i. Spec. Publ.

313. 177 pages ( May 19(39 i . 81.50. SP315. Bibliography on the high temperature chemistry and physics of materials, October, November, December 1968, J. J. Diamond. Edit or. Xat. Bur.

Stand. (U.S. i. Spec. Publ. 315. 72 pages (Jan. 1969 i. 70 cents. SP315-1. Bibliography on the high temperature chemistry and physics of materials, January, February, March 1969, J. J. Diamond. Editor. Nat. Bur. Stand.

( U.S. ) . Spec. Publ. 31.5-1. SI pages ( April 1969 i . 75 cents. SP316. Hydraulic research in the United States, 1968, G. Kulin. Editor. Nat. Bur.

Stand. (U.S. ), Spec. Publ. 316. 331 pages ( June 1969). 82.50. National Standard Reference Data Series. Includes the evaluated reference data and critical reviews of long-term interest that are prodticed by data centers within the NSRDS network. The X'ational Standard Reference Data System is a Government-wide effort to provide the U.S. technical community with effective access to the quantitative data of physical science, critically evaluated and compiled for convenience. XSRDS-XBS15. Molten salts : Volume 1. Electrical conductance, density, and

viscosity data, G. J. Janz. F. W. Dampier, G. R. Lakshminarayanan. P. K.

Lorenz. and R. P. T. Tomkins. Xat. Stand. Ref. Data Ser.. Xat' Bur. Stand.

(; U. S. ') . 15. 145 pages (, Oct. 196S i . 83.00. XSRDS-XBS19. Thermod^^lamic properties of ammonia as an ideal gas, L. Haar.

Xat. Stand. Ret Data Ser., Xat. Bur. Stand. (U.S. i, 19, 13 pages (Aug. 196S). 20 cents. XSRDS-XBS20. Gas phase reaction kinetics of neutral oxygen species, H. S. Johnston, Nat Stand. Ret Data Ser.. X'at. Bur. Stand. (*U.S.). 20, 54 pages

(Sept. 1968). 45 cents. XSRDS-XBS24. Theoretical mean activity coefficients of strong electrolvtes in aqueous solutions from 0 to 100 =C. AV.'j. Hamer. Xat. Stand. Ret Data Ser..

^ Xat. Bur. Stand. ( U.S. ) . 24. 276 pages ( Dec. 1968 i . 84.25. XSRDS-XBS25. Electron impact excitation of atoms, B. L. Moiseiwitsch and

S. J. Smith, Xat Stand. Ret Data Ser.. Xat Bur. Stand. (U.S. t 25. 120 pages

(Aug. 1968). .$2.00.

.

, - . = NSRDS-NBS26. Ionization potentials, appearance potentials, and heats of formation of gaseous positive ions, J. L. Franklin. J. G. Dillard. H. M Ro^enstock. J. T. Herron. K. Draxl. and F. H. Field. Nat. Stand. Ret Data Ser..

X'at. Bur. Stand. (U.S.i. 26. 2s9 pages (June 1969). -Sl.uO. X'SRDS-X"BS27. Thermodynamic properties of argon from the triple point to 300 K at pressures to 1000 atmospheres. A. L. Gosman. R. D. McCartv. and

J. G. Hust Xat Stand. Ret Data Ser,. Xat. Bur. Stand. (U.S.). 27. 151*pa^e< (Mar. 1969). 81.25.

^.

. i .

- Building Science Series. Dis.seminates technical information developed at the Bureau on building materials, components, systems, and whole structures. The

206
series presents research results, test methods, and performance criteria related

to the structural and environmental functions and the durability and safety

characteristics of building elements and systems.

BSS14. Experimental determination of eccentricity of floor loads applied to a bearing wall, D. Watstein and P. V. Johnson, Nat. Bur. Stand. (U.S.), Bldg. Sci. Series 14 (June 1968) . 15 cents. BSS15. Interrelations between cement and concrete properties. Part 4. Shrink- age of neat portland cement pastes and concretes. (Contains section 9 and

section 10.) R. L. Blaine, H. T. Arni, and D. N. Evans, Nat. Bur. Stand. (U.S.), Bldg. Sci. Series 15, Part 4, 79 pages (Mar. 1969) . 75 cents. BSS16. Techniques for the survey and evaluation of live floor loads and fire loads in modern office buildings, J O. Bryson and D. Gross, Nat. Bur. Stand.

(U.S.), Bldg. Sci, Series 16, 32 pages (Dec. 1968) . 40 cents. BSS17. Causes of variation in chemical analyses and physical tests of portland

cement, B. L. Bean and J. R. Dise, Nat. Bur. Stand. (U.S.), Bldg. Sci. Series

17, 34 pages (Mar. 1969). 40 cents. (Supersedes Monograph 28.) BSS18. Smoke and gases produced by burning aircraft interior materials, D.

Gross, J. J. Loftus, T. G. Lee, and V. E. Gray, Nat. Bur. Stand. (U.S.), Bldg.

Sci. Ser. 18, 29 pages (Feb. 1969) . 35 cents. BSS19. A study of the variables involved in the saturating of roofing felts, S. H.

Greenfeld, Nat. Bur. Stand. (U.S.), Bldg. Sci. Ser. 19, 18 pages (June 1969). 80 cents. Applied Mathematics Series. Mathematical tables, manuals, and studies of special interest to physicists, engineers, chemists, biologists, mathematicians,

computer programmers, and others engaged in scientific and technical work. Some of the volumes are reissues of the Mathematical Tables prepared by the Project for the Computation of Mathematical Tables conducted by the Works

Projects Administration for the City of New York under the scientific sponsor- ship of NBS.

AMS60. Matrix representations of groups, M. Newman, Nat. Bur. Stand. (U.S.), Appl. Math. Series 60, 82 pages (July 1968). 60 cents. Federal Information Processing Standards Publications. (FTPS PUBS) The

publications in this series collectively constitute the Federal Information Process- ing Standards Register. The purpose of the Register is to serve as the official source of information in the Federal Government regarding (1) uniform Federal information processing standards resulting from provisions of Public Law

89-306 (the Brooks Bill) and (2) data elements and codes standards in data systems developed under the provisions of Bureau of the Budget Circular No. A-86. FTPS PUBS will include approved Federal information processing stand- ards information of general interest, and a complete index of relevant standards

publications.

FIPS PUB 0. General description of Federal Information Processing Standards

register, H. S. White, Jr., Editor, Nat. Bur. Stand. (U.S.), Fed. Info. Process. Stand. Publ. (FIPS Pub.) 0, 8 pages (Nov. 1, 1968). 20 cents. FIPS PUB 1. Code for information interchange. Hardware standard inter- change codes and media, H. S. White, Jr., Editor, Nat. liiir. St;ind. (U.S.), Fed.

Info. Process. Stand. Publ. (FIPS Pub.) 1, 4 pages (Nov. L IDCS). 10 cents. FIPS PUB 2. Perforated tape code for information interchange. Hardware

standard interchange codes and media, II. S. White, Jr., Editoi-, Nat. Bur.

Stand. (U.S.), Fed. Info. Process. Stand. Publ. (FI1»S Pub. ) 2. 4 pages (Nov. 1, 1968). 10 cents. FIPS PUB 3. Recorded magnetic tape for information interchange (800 CPI,

NRZI). Hardware standard interchange codes and media, If. S. \\ hil(\ Jr., Editor, Nat. Bur. Stand. (U.S.), Fed. Info. Process. Stand. Publ. (FIPS Pub.)

3, 4 pages (Nov. 1, 1968 ) . 10 cents. FIPS PUB 4. Calendar date (Federal general data standard representations

and codes), H. S. White, Jr., Editor, Nat. P.ur. Slniid. (U.S.), Fed. Info. Process. Stand. Publ. (FIPS Pub.) 4,4 pages ( .Xov. 1. i;m;S). 20 cents. FIPS PUB 5. States of the United States (Federal general data standard rep- resentations and codes), II. S. White, .Ir.. I']<Ii(()r. Nat. liur. Sland. (U.S.), Fed. Info. Process. Stand. Publ. (FIPS Pub.) 5, 4 i)ages (Xov. 1, IJXI.s). 20

cents. 207
FIPS PUB 6. Counties of the States of the United States (Federal general data standard representations and codes), H. S. WMte, Jr., Editor, Nat. Bur. Stand.

(U.S.), Fed. Info. Process. Stand. Publ. (FIPS Pub.) 6, 32 pages (Nov. 1, 1968). 40 cents. FIPS PUB. 7. Implementation of the code for information interchange and

and related media standards. Hardware standards interchange codes and

media, H. S. White. Jr., Editor, Nat. Bur. Stand. (U.S.), Fed. Info. Process. Stand. Publ. (FIPS Pub.) 7, 14 pages (Mar. 7, 1969). 25 cents. (Supplement to FIPS Publ. 1 through 3.) FIPS Pub. 8. Metropolitan statistical areas. Federal general data standard rep- resentations and codes, H. S. White, Jr., Editor, Nat. Bur. Stand. (U.S.), Fed.

Info. Process. Stand. Publ. (FIPS Pub.) 8, 8 pages (June 9, 1969). 20 cents. Product Standards. This series comprises voluntary standards that establish

(1) dimensional requirements for standard sizes and types of various products;

(2) technical requirements for the product and (3) methods of testing grading,

and marking these products. The objective is to define requirements for products

in accordance with the principal demands of the trade. PS9-68. Fabrics for book covers, J. Eisele, Technical Standards Coordinator,

Nat. Bur. Stand. (U.S.), Prod. Stand. 9-68, 13 pages (Apr. 1968). 10 cents.

( Supersedes Commercial Standard CS 7-40.

)

Technical Notes. Designed to supplement the Bureau's regular publications program, Technical Notes provide a publication medium for communications and

reports on data of limited or transitory interest. They often serve as final reports on work at NBS sponsored by other Government agencies.

TN366. An analysis of the Brayton cycle as a cryogenic refrigerator, R. C. MuhlenhauDt and T. R. Strobridge, Nat. Bur. Stand. (U.S.), Tech. Note 366, 116 pages (Aug. 1968). $1.25. TN367. A bibliography of thermophysical properties of methane from 0 to 300 °K, L. A. Hall, Nat. Bur. Stand. (U.S.), Tech Note 367, 121 pages (May

1968). 60 cents. TN368. Solution of the Abel integral transform for a cylindrical luminous

region with optical distortions at its boundary, E. R. Mosburg, Jr., and M. S. Lojko, Nat. Bur. Stand. (U.S.), Tech. Note 368, 27 pages (July 12, 1968). 25 cents. TN369. Interferometric measurements of the complex dielectric constant of

liquids, W. S. Lovell and L. M. Thiel, Nat. Bur. Stand. (U.S.), Tech. Note 369, 89 pages (Aug. 1968) . 50 cents. TN370. Calibration principles and procedures for field strength meters (30 Hz

to 1 GHz), H. E. Taggart and J. L. Workman, Nat. Bur. Stand. (U.S.), Tech. Note 370, 157 pages (Mar. 1969). $1.25. TN371. Transistorized low voltage regulator circuits and design, J. H. Rogers,

Nat. Bur. Stand. (U.S.), Tech. Note 371. 38 pages (Sept. 1968). 30 cents. TN372. jMathematical techniques for EPR analysis of S=5/2 ions in C2 symmetry. Application to Fe^* in quartz, R. L. Petersen, L. M. Matarrese, and J. S. Wells, Nat. Bur. Stand. (U.S.), Tech. Note 372, 23 pages (June 1969). 35 cents. TN373. Radio-frequency measurements in the NBS Institute for Basic Standards, R S. Powers and W. F. Snyder, Editors, Nat. Bur. Stand. (U.S.), Tech. Note 373, 116 pages (June 1969) . $1.00. TN374. Incipient and developed cavitation in liquid cryogens, D. K. Edmonds

and J. Hord, Nat. Bur. Stand. (U.S.), Tech. Note 374, 31 pages (Feb. 1969). 35 cents. TN375. Tables of bias functions, Bi and Bo for variances based on finite samples

of processes with pov/er law spectral densities, J. A. Barnes, Nat. Bur. Stand.

(U.S. )

, Tech. Note 375, 39 pages (Jan. 1969) . 50 cents. TN377. Slush hydrogen fluid characterization and instrumentation, C. F. Sindt, P. R. Ludtke, and D. E. Daney, Nat. Bur. Stand. (U.S.), Tech. Note 377, 69 pages (Feb. 1939). 65 cents. TN378. Preparation and characterization of slush hydrogen and nitrogen gels, A. S. Rapial and D. E. Daney, Nat. Bur. Stand. (U.S.), Tech. Note. 37S, 43 pages (May 1969) . 50 cents. TN4.32. Connection tables from Wiswesser chemical structure notation—a partial algorithm, G. F. Fraction, J. C. Walker, and S. J. Tauber, Nat. Bur. Stand.

( U.S. )

, Tech. Note. 432, 63 pages ( Sept. 1968) . 65 cents. 208
TN433. Input/output packages for the systems 360 assembly language processor,

P. A. D. deMaine, Nat. Bur. Stand. (U.S.), Tech. Note 433, 14 pages (Sept.

1968). 25 cents. TN436. Studies of calibration procedures for load cells and proving rings as weighing devices, G. B. Anderson and R. C. Raybold, Nat. Bur. Stand. (U.S.), Tech. Note 438, 22 pages (Jan. 1969) . 30 cents. TN441. Tabulation of published data on Soviet electron devices through Octo- ber 1967, C. P. Marsden, Nat. Bur. Stand. (U.S.), Tech. Note 441, 98 pages

(July 1968) . 55 cents. ( Supersedes Technical Note 265.

)

TN444. Reform: a general-purpose program for manipulating formatted data

files, R. McClenon and J. Hilsenrath, Nat. Bur. Stand. (U.S.), Tech. Note 444, 28 pages (Aug. 1968) . 40 cents. TN447. Research on high temperature materials at the National Bureau of Standards, E. Passaglia, Editor, Nat. Bur. Stand. (U.S.), Tech. Note 447, 19 pages (July 1968). 20 cents. TN451. Radiochemical Analysis Section: summary of activities July 1967 to June 1968, J. R. DeVoe, Editor, Nat. Bur. Stand. (U.S.), Tech. Note 451, 131 pages (Jan. 1989). $1.25. TN452. Activities of the NBS Spectrochemical Analysis Section July 1967 through June 1968, B. F. Scribner, Editor, Nat. Bur. Stand. (U.S.), Tech. Note

452, 80 pages ( Sept. 1968). $1.00. TN453. Elecrochemical Analysis Section: summary of activities July 1967 to June 1968, R. G. Bates, Editor, Nat. Bur. Stand. (U.S.), Tech. Note 453, 88 pages (July 1968). 55 cents. TN454. Analytical Coordination Chemistry Section: summary of activities July

1967 to June 1968, O. Menis, Editor, Nat. Bur. Stand. (U.S.), Tech. Note 454, 92 pages (July 1968). 55 cents. TN 455. Microchemical Analysis Section: summary of activities July 1967 to June 1968, J. K. Taylor, Editor, Nat. Bur. Stand. (U.S.), Tech. Note 4.55, 145 pages (Oct. 1968). $1.25. TN456. Analytical Mass Spectrometry Section: summary of activities July 1967

to June 1968, W. R. Schields, Editor, Nat. Bur. Stand. (U.S.), Tech. Note 456, 54 pages ( Nov. 1968 ) . 55 cents. TN457. Organic Chemistry Section: summary of activities July 1967 to June

1968, R. Schaffer, Editor, Nat. Bur. Stand. (U.S.), Tech. Note 457, 127 pages

( Sept. 1968). $1.25. TN458. Activation Analysis Section: summary of activities July 1967 to June

1968, P. D. LaFleur, Editor, Nat. Bur. Stand. (U.S.), Tech. Note 458, 109 pages

(Mar. 1969). $1.00. TN459. Separation and Purification Section: summary of activities July 1967 to June 1968, D. H. Freeman, Editor. Nat. Bur. Stand. (U.S.), Tech. Note 459, 56 pages (Dec. 1968). 60 cents. TN461. Tables of solutions to Bragg's equation for copper, cobalt, iron, and

chromium Ka" radiation and small diffraction angles, J. P. Colson and E. S. Clark, Nat. Bur. Stand. (U.S.), Tech. Note 461, 75 pages (Aug. 1968). 50 cents. TN462. Nonnumeric data processing in Europe : a field trip report, M. E. Stevens, Nat. Bur. Stand. (U.S.), Tech. Note 462, 66 pages (Nov. 1968). 65 cents. TN463. Mossbauer efifect study of magnetic ordering in copper-rich Cu-Ni-Fe

alloys, L. J. Swartzendruber, Nat. Bur. Stand. (U.S.), Tech. Note 463, 138 pages (Aug. 1968). 25 cents. TN464. The NBS Alloy Data Center : function, bibliographic system, related data centers and reference books, G. C. Carter, L. H. Bennett, J. R. Cuthill, and

D. J. Kahn, Nat. Bur. Stand. (U.S.), Tech. Note 464, 199 pages (Aug. 1968).

$1.25. TN465. Measurement of carrier liftime in semiconductors—an annotated bibli- ography covering the period 1949-1967, W. M. Bullis, Nat. Bur. Stand. (U.S.), Tech. Note 465, 64 pages (Nov. 1968) . 60 cents. TN466. Matching fingerprints by computer, J. IT. Wegstein, J. F. Ralforty, and

W. J. Pencak, Nat. Bur. Stand. (U.S.), Tech. Note 466, 17 pages (July 1968). 20 cents. TN467, Part 1. Activation analysis: a bibliography, G. J. Lutz, R. J. UoiHiii. R.

S. Maddock, and W. W. Moinke, Editors, N:it. P>nr. Stand. (U.S.), Tocli. Note

467, Part 1, 520 pages (Sept. VMW). .$('..50. I'.nt 1 is sold only with Part 2. TN467, Part 2. Appendices. Activation analysis: a bibliography, (I. J. Tiiitz, K. J. Boreni, R. S. Maddock, and W. W. Mciiikc, Edilors, Xat. P,ur. Stand. ( U.S.), Tech. Note 467, Part 2, 197 pages (Sept. 1968). $(;.50. I'art 2 is .^old oiilv with Part 1. 209
TN469. NBS interagency transducer project, P. S. Lederer, Nat. Bur. Stand.

( U. S ) ., Tech. Note 469, 23 pages ( Oct. 1968 ) . 30 cents. TN470. Edpac : utility programs for computer-assisted editing, copy-production,

and retrieval, C. G. Messina and J. Hilsenrath, Nat. Bur. Stand. (U.S.), Tech. Note 470, 80 pages (Jan. 1969) . 75 cents. TN472 Methods of measurement for semiconductor materials, process control, and devices. Quarterly report July 1 to September 30, 1968, W. M. BuUis,

Editor, Nat. Bur. Stand. (U.S.), Tech. Note 472, 45 pages (Dec. 1968). 50 CGnts TN473 Laboratory-field comparison of built-up roofing membranes, T. H. Boone,

L. F. Skoda, and W. C. CuUen, Nat. Bur. Stand. (U.S.), Tech. Note 473, 15 pages (Dec. 1968). 25 cents. TN474 Critically evaluated transition probalities for Ba I and II, B. M. Miles and W. L. Wiese, Nat. Bur. Stand. (U.S.), Tech. Note 474, 22 pages (Jan. 1969). 30 cents. . , ^ , TN475 Methods of measurement for semiconductor materials, process control, ^and devices. Quarterly report October 1 to December 31, 1%8, W. M. Bullis, Editor, Nat. Bur. Stand. (U.S.), Tech. Note 475, 38 pages (Feb. 1969). 45 TN476 Line emission sources for concentration measurements and photochemistry, *W. Braun and T. Carrington, Nat. Bur. Stand. (U.S.), Tech. Note 476, 23 pages (Mar. 1969). 30 cents. TN477 The performance of roofing made with Asplund felts, S. H. Greenfeld, Nat. Bur. Stand. (U.S.), Tech. Note 477, 27 pages (Mar. 1969). 35 cents. TN478 Some evolving conventions and standards for character information

coded in six, seven, and eight bits, J. L. Little, Nat. Bur. Stand. (U.S.), Tech. Note 478, 30 pages (May 1969) . 35 cents. TN479. A Fortran program for analysis of ellipsometer measurements, F. L. McCrackin, Nat. Bur. Stand. (U.S.), Tech. Note 479, 82 pages (Apr. 1969). 75

cents. TN480. Misalinement detector for axial loading fatigue machines, D. C. Robinson, Nat. Bur. Stand. (U.S.), Tech. Note 480, 15 pages (Apr. 1969). 25 cents. TN481. A semi-automated single fingerprint identification system, J. H. Wegstein, Nat. Bur. Stand. (U.S.), Tech. Note 481, 21 pages (Apr. 1969). 30 cents. TN482. Superconductive materials and some of their properties, B. W. Roberts,

Nat. Bur. Stand. (U.S.), Tech. Note 482, 129 pages (May 1969). $1.25. TN483. Construction and operation of a simple high-precision copper-point

blackbody and furnace, R. D. Lee, Nat. Bur. Stand. (U.S.), Tech. Note 483, 16 pages (May 1969) . 30 cents. TN484. A review of rate constants of selected reactions of interest in re-entry

flow fields in the atmosphere, M. H. Bortner, Nat. Bur. Stand. (U.S.), Tech. Note 484, 62 pages (May 1969) . 60 cents. PUBLICATIONS IN OUTSIDE JOURNALS

Abrams, M. D., A comparative sampling of the systems for producing computerdrawn flow charts, Proc. 1968 ACM National Conf., Las Vegas, Nev., Aug. 27-

29, 1968, pp. 743-750 (Brandon/Systems Press Inc., Princeton, N.J., 1968).

Acquista, N., Abramowitz, S., Lide, D. R., Structure of the alkali hydroxides. II. The infrared spectra of matrix isolated CsOH and CsOD, J. Chem. Phys. 49, No. 2, 780-782 (July 15, 1968)

.

Ahearn, A. J., Paulsen, P. J., Workshop on mass spectrometric analysis of solids at the National Bureau of Standards in Gaithersburg, Md., Nov. 18 and 19, 1968, Anal. Chem. 41, No. 2, 79A-81A (February 1969).

Allan, D. W., Guetrot, A., Higbie, L, S., Lavanceau, J. D., An application of

statistical smoothing techniques on VLF signals for comparison of time be- tween USNO and NBS, Proc. 23rd Frequency Control Symp., Atlantic City,

N.J., May &-8, 1969, p. 248 (1969). Altschuler, H. M., Comments on An Improved method for measuring scattering

parameters of nonreciprocal two-ports, IEEE Trans. Microwave Theory Tech. MTT-16, No. 4, 261-262 (April 1968)

.

Alvarez, R., Paulsen, P. J., Kelleher, D. E., Simultaneous determination of trace elements in platinum by isotope dilution and spark source mass spectrometry,

Anal. Chem. 41, No. 7, 955-958 (June 1969)

.

Amona, T., Saito, S., Hirota, E., Morino, Y. Johnson, D. R., Powell, F. X., Micro- wave spectrum of the CIO radical, J. Mol. Spectry. 30, No. 2, 275-289 (May

1969).

210
Ambler, E., Schooley, J. F., Colwell, J. H., Pfeiffer, E. R., Frederikse, H. R., Hosier, W. R., Thurber, W. R., Transition temperatures and critical fields of SrTiO^ and mixed titanates, Proc. Xth Intern. Conf. Low Temperature Physics,

Moscow, U.S.S.R., Aug. 31-Sept. 6, 1966, Vol. 2B, Superconductivity, Paper

8123,142-148 (1968).

Anderson, H. J., Brenner, A., Preparation of rhenium hexafluoracetylacetonate,

J. E'lectrochem. Soc. 116, No. 4, 513 (April 1969).

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237
PATENTS

Tlie following U.S. Patents have been granted to NBS inventors and assigned

to tlie United States of America, as represented by the Secretary of the Depart- ment noted in parentheses

:

Ruehrwein, Robert A., and Hashman, Joseph S., No. 3,378,351, April 16, 196&

Complex Compounds of Molecular Oxygen ( Army )

.

Wall, Leo A., and Antonucci, Joseph M., No. 3,394,190, July 23, 1968. Synthesis

of Perfluoroparacresol, Polyoxyperfluorobenzylene and Related Monomers and

Polymers (Navy).

Henig, Seymour, and Palasky, Ervin C, No. 3,397,392, August 13, 1968. Information Storage and Category Selector (Commerce).

Thompson, Moody C, Jr., and Vetter, Maurice J., No. 3,4(X),330, September 3, 1968. Refractometer That Measures the Difference in Refractive Indices of a Gas at Two Frequencies (Commerce).

Carlson, John G., No. 3,410,100, November 12, 1968. High Vacuum Baffle Using

Cooled Chevron-Shaped Members (Commerce).

Cruz, Jose E., No. 3,417,350, December 17, 1968. Variable Impedance Device with

Relative Rotation Between Conductors (Commerce).

Bender, Peter L., and Owens, James C, No. 3,424,431, January 28, 1969. A Dis- tance Measuring Instrument Using a Pair of Modulated Light Waves (Commerce).

Wall, Leo A., and Antonucci, Joseph M., No. 3,429,935, February 25, 1969. High

Temperature Substitution Reactions of Hexafluorobenzene (Navy).

Thompson, Moody C, Jr., and Wood, Lockett E., No. 3,437,820, April 8, 1969. Optical Distance Measuring Equipment Utilizing Two Wavelengths of Light

in Order to Determine and Compensate for the Density of the Air (Commerce).

Thompson, Moody C, Jr., and Wood, Lockett E., No. 3,437,821, April 8, 1969. Radio—Optical Refractometer for Measuring Integrated Water-Vapor Refractivity (Commerce).

238

U.S. GOVERNMENT PRINTING OFFICE: 1970