NBS

PUBLICATIONS

Cooperative Research Opportunities at NBS

NATIONAL BUREAU OF STANDARDS • U.S. DEPARTMENT OF COMMERCE

A111DE blL7bfl

QC

100

• U57

No- 723

1986
U S DEPARTMENT OF COMMERCE

Malcolm Baldrige, Secretary

National Bureau of Standards

Ernest Ambler. Director

National Bureau of Standards

Gaithersburg. MD 20899

301/975-2000

National Bureau of Standards

Boulder, CO 80303

303/497-3000

December 1986

NBS Special Publication 723

Library of Congress

Catalog Card Number:

86-600570 CODENXNBSAV

Any mention of commercial products

is for information only; it does not imply recommendation or endorsement

by the National Bureau of Standards

nor does it imply that the products mentioned are necessarily the best

available for the purpose.

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington. D C. 20402
Contents

Message from the Director 3

Cooperative Research at NBS jt4

Research Opportunities oo

Analytical Chemistry 9

Applied Mathematics 14

Basic Standards 15

Building Technology 19

Ceramics 22

Chemical Engineering 25

Chemical Physics 29

Computer Sciences and Technology 31

Electronics and Electrical Engineering 33

Fire Research 37

Fracture and Deformation 38

Manufacturing Engineering 39

Metallurgy 40

Neutron Scattering and Diffraction 43

Nondestructive Evaluation 44

Polymers 45

Product Standards 48

Radiation Research 49

Standards Reference Data 52

NBS

RESEARCH

INFORMATION CENTER

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NBS Gaithersburg laboratories.

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Message from the Director

Our primary goal as the nation's physical sciences and engineering measurement

laboratory is to serve industry and

science—to make sure our research is helping the nation solve its measurement

problems. By doing so, we help industry exploit the nation's science and technology in

its quest to compete successfully in the in- ternational marketplace.

At the National Bureau of Standards, we

found long ago that one of the most effective ways to accomplish this is through

cooperative research. Each year more than 900 people from industry, universities, and

other government agencies work side-by- side with NBS scientists and engineers on

a wide range of research projects including

automated manufacturing, biotechnology,

computer networking, and mechanical

failure of materials. Because I firmly believe we will best meet today's economic and technological

challenges by working together, we are in- creasing the opportunities for cooperative

research here at the National Bureau of Standards. Let me mention just briefly the advantages, as I see them, of collaborative research to both NBS and the cooperating

organization. Researchers from industry, universities, and other government agencies get an opportunity to work with NBS specialists, many of whom are renowned experts in their fields, and to use the Bureau's

premier research and testing facilities. They

take newly developed technology back to

their organizations to be incorporated im- mediately into new ideas, new processes, and new products. NBS researchers, in turn, learn firsthand the views and needs of Bureau clients and, as a result, we are better able to direct our research to meet

these needs. One of our longest running cooperative

projects has been a remarkably successful

collaboration with the American Dental

Association. Started in 1928, the alliance has resulted in the panoramic x-ray machine, composite restorative materials, and the high-speed turbine handpiece, for example, as well as major contributions to dozens of standards for dental materials and hundreds of scientific papers. The scope, duration, and structure of our

cooperative projects are tailored to the prob- lem to be solved. They can last for a few

weeks or a few years and involve one,

several, or even hundreds of organizations.

Our goal is to solve the problem at hand

quickly, efficiently, and effectively.

I invite you to review the research opportunities described in this brochure, and

then to call us to discuss the possibilities for collaborative research in an area that is of concern to both of us. By working together, we can facilitate technology transfer, help

improve industrial productivity, and

strengthen this nation's ability to compete in international markets.

Ernest Ambler

Director

Cooperative Research at NBS

Numerous opportunities exist for scientists and engineers from industrial, professional,

trade, and other organizations to collab- orate in research at the National Bureau

of Standards on projects of mutual interest. To accomplish its objective of supplying the measurement foundation for industry,

science, and technology, NBS conducts

research in many areas, including ad- vanced ceramics, automated manufacturing, optoelectronics, and biotechnology.

Operated on an annual budget of about

$210 million, the Bureau employs a highly

skilled staff of some 2,700 at its headquarters in Gaithersburg, Md., and its site

in Boulder, Colo. NBS also has extensive research and testing facilities that are

available for use in cooperative research,

such as a 20-megawatt research reactor, an electron accelerator, a synchrotron

ultraviolet radiation facility, a supercomputer, a large-scale structures testing facility, a metals-processing laboratory, a fire research facility, and a computer network

protocol testing and evaluation laboratory.

NBS will work with a company, trade

association, university, or other government

agency to solve problems of mutual concern. One of the most popular ways NBS

research and facilities are made accessible

to U.S. industry is through the Bureau's In- dustrial Research Associate Program.

Under this program, companies, trade

associations, and technical societies pay

their scientists and engineers to work in NBS laboratories with NBS researchers on

a specific project.

In another type of cooperative venture, companies subscribe to a consortium that provides resources to have NBS solve a

specific measurement problem facing the

industry. This arrangement has advantages

when a complex problem confronts a parti- cular industry and the research is too costly or not possible for individual companies to undertake. Companies also loan or donate equip- ment or software to the Bureau when NBS

researchers are working on a project that could ultimately improve their products or the way they do business. In such situations, these firms actively consult or advise NBS researchers on the needs and con- cerns of the industry. In other cases, NBS

makes its facilities available to companies

for proprietary research on a cost-recovery

basis, when equal or superior facilities are

not otherwise available.

Described below are a few brief ex- amples of different types of cooperative

projects and the results they have pro- duced so far.

Manufacturing Research Facility

The NBS Automated Manufacturing

Research Facility (AMRF), a research

center for studying fundamental questions

affecting factory automation, is one of the

largest cooperative programs at the Bureau. Since 1982, 35 companies—large

and small—have paid more than 50 of their researchers to work in the AMRF, and

about $4.6 million worth of equipment and

software has been loaned or donated to NBS by industry for this project. The Navy

Manufacturing Technology Program is a

major partner in the facility, and the Air Force Intelligent Task Automation Project

and other government agencies also have

sponsored specific parts of the AMRF effort. In addition, a number of universities have contributed to the project by loaning

guest researchers. Together these researchers are ex- perimenting with methods for getting

robots, computers, and machine tools from

different manufacturers to communicate

and work together in an integrated system

through standardized interfaces. Their other primary goal is to find a means for controlling quality in a fully automated factory en- vironment by improving the measurement

process.

All of this will give companies, in parti- cular small firms with less than 50

employees, the flexibility to buy equipment

from different manufacturers at different times with the assurance that the machines

they buy can be made to work together

without expensive, custom-designed inter- faces. Concepts developed at the AMRF

are now being adopted by hardware

manufacturers and the U.S. Navy.

According to a study by the Management Collaborative Group of Chapel Hill, N.C., the contribution of the AMRF to the increased use of numerical-control machine tools in U.S. industry will pro- duce a savings to the metalworking in- dustry of between $250 and $760 million per year by 1990.

Chemical Engineering Consortia

NBS recently completed a 4-year re- search project on the properties of supercritical fluids which was sponsored by a

consortium of 14 private companies and
the Department of Energy. The goal of

this research was to develop accurate

predictive models for supercritical fluid mixtures and accurate experimental data

that can be used to test and further de- velop the predictive models. Among the

results of this effort is a state-of-the-art computer code to be used in the custody

transfer of supercritical fluid mixtures. Meetings of the consortium participants were held twice a year where research

results were disseminated and direction of the project discussed. This effort was judged so successful by the participants that two new consortia were formed from it. NBS researchers are working on two

other consortium-sponsored projects in chemical engineering. One consortium,

which is studying the measurement prob- lems that result when a meter is installed too close to a pipe elbow or valve, has 10

firms and the Department of Energy as members. The other consortium has a

roster that includes nine companies and the

National Aeronautics and Space Administration, all of which are interested in im- proving the performance of vortex-shedding

flow meters.

Collaborative Research in Microwave

Technology

To refine techniques for rapidly dissolving

samples in closed vessels within a microwave chamber, CEM Corporation, a producer of microwave equipment for research purposes, sent one of its chemists

to NBS to work as an industrial research

associate with Bureau researchers. As a

result of this cooperative project, microwave

technology can now be used to dissolve samples—everything from biological spec- imens such as human bone and bovine

livers to botanical, geological, metallic, and

glassy samples— more safely and efficiently than traditional methods. By combining the microwave technique's

ability to heat materials quickly with the

superior dissolving properties of closed

containers under pressure, the NBS/CEM

research team has designed a method for breaking down samples that takes less than 10 minutes. Traditionally, using hot

plates and open-vented beakers, scientists could expect dissolving times of anywhere

from 4 hours to 4 days, depending on the complexity of the sample.

The researchers have produced a database of information that will allow in- dustrial chemists to tailor their own

microwave devices for desired results. They

are also helping others apply their techni- ques: So far they have given information and advice to more than 250 researchers from companies, universities, and research

laboratories.

Biotechnology Center

In a first-of-its-kind agreement for NBS, the Bureau, The University of Maryland, and

Montgomery County, Md., are establishing a Center for Advanced Research in Biotechnology (CARB) to provide a forum

for collaborative research among academic,

government, and industrial scientists. When

the new CARB building is completed in December 1987, it is expected to house

state-of-the-art facilities and 1 00 researchers from NBS, The University of Maryland, in- dustry, and other government agencies

and universities. The goal of the center is to radically reduce the time and effort required to de- termine the atomic structure of proteins and

to model and predict their properties. This research will help build the foundation for the rapidly emerging fields of protein en- gineering and rational drug design.

Phase Diagram Center ASM International has raised $4 million as

industry's portion of a cooperative

ASM/NBS program that will give scientists and engineers more reliable data, in the form of alloy phase diagrams, for designing new and better metal alloys and products

in which metal alloys are used. Fifty companies, organizations, institutes and agencies, and hundreds of individuals made

contributions to ASM.

Researchers from NBS and industry

work in the Alloy Phase Diagram Center, which is located at NBS. ASM and NBS

also support individual data evaluation pro- grams in other laboratories. The critically evaluated phase diagrams, which are graphic representations of what happens

when two or more elements are combined at various temperatures and

pressures, are published by ASM as part

of the collaborative effort. Data from the ASM/NBS program are expected to save

U.S. firms hundreds of millions of dollars.
Computer Networking Workshops

For the past several years, NBS has been

working with industry and standards groups to make it easier for those using

computer systems or equipment to communicate with each other through computer networks regardless of who

manufactures the individual pieces. NBS

has cooperated with the standards groups to develop the needed standards and with industry to implement and test the standards in commercial products for the office and factory. As part of this project, NBS sponsors a

series of workshops for vendors and

users to discuss the implementation of the Open Systems Interconnection (OSI) Reference Model. To date, over 200

companies, including most major computer

manufacturers, communications carriers, semiconductor companies, factory control system companies, and word processing

manufacturers, as well as government

agencies have participated in the workshops.

Two successful demonstrations—one at the 1984 National Computer Conference,

the other at AUTOFACT '85—of standards

for the OSI reference model have resulted. These cooperative activities have now led

to the use of new computer network proto- cols by several hundred companies for manufacturing and office automation.

How to Participate

These examples illustrate the range of cooperative programs that it is possible to establish—from a small, very focused proj- ect with limited resources to those in which numerous organizations are contributing to research that will affect an entire industry. If you are interested in working with NBS on

a project, large or small, write or call one of the offices listed below or one of the contacts given in the Research Opportunities

section of this brochure. • Industrial Research Associate Program

Under this program, which NBS has run

since the 1920's, scientists and engineers

from industry, trade associations, technical

societies, and other organizations work

side-by-side with NBS researchers. With

their salaries paid by their employers, the associates work at NBS, usually for 1 to 3

years, on a wide range of research includ- ing robotics, computer science, advanced

ceramics, and nondestructive analysis. For

further information, contact the NBS Office

of Research and Technology Applications,

301/975-3087. • Proprietary Facilities While most NBS facilities are available for cooperative research, the Bureau recently

opened up selected facilities for proprietary research. NBS makes these facilities available under certain conditions to support U.S. industry in its development of new competitive products and processes. For additional information, contact the NBS

Program Office, 301/975-2657. • Other Arrangements

To inquire about other types of cooperative

research programs with NBS, such as a

consortium or research center, contact the appropriate institute or laboratory.

Institute for Materials Science and

Engineering, 301/975-5658: Provides stan- dards, measurement methods, data, and

quantitative understanding to aid in improving the processing and performance of metals, polymers, ceramics, composites,

and glasses. National Measurement Laboratory,

301/975-4500: Provides the nation with

state-of-the-art measurement services in thermodynamics, transport properties,

chemical kinetics, surface science, molecular spectroscopy, and chemical analysis.

Conducts research to improve realization of basic physical quantities.

Institute for Computer Sciences and

Technology, 301/975-2819: Provides the standards, specifications, measurement and

test methods, and technical guidance

needed by government and industry to make better use of computer hardware,

software, networks, and security. National Engineering Laboratory,

301/975-2301: Conducts research in en- gineering and applied science. Studies prob- lems in electronics, manufacturing

automation, chemical engineering, the be- havior (and prevention) of fires, and the design and construction of buildings.
Research Opportunities

NBS welcomes collaboration with scientists and engineers from industry, universities, and other government agencies on most of

its projects. To give those interested in cooperative research an idea of the wide

range of NBS programs, a sampling of specific Bureau research projects is described on the following pages.

To discuss the possibility of setting up a

cooperative research project in one of these areas, write or call the contact listed. (Unless otherwise specified, all contacts are

at the National Bureau of Standards,

Gaithersburg, MD 20899.) For general

information on cooperative research at NBS, write or call one of the offices listed on page 7.

At the horizontal workstation in the NBS Automated Manufacturing Research Facility, physicists Christopher Stevenson (left) of White-Sundstrand and Howard Harary of NBS discuss the next generation of machine tools.

8
Analytical Chemistry

Atomic

Spectroscopy

Analytical Mass

Spectrometry

Atomic spectroscopy methods are probably the most widely used analytical tech- niques in industry today. Considerable

research is required, however, to keep

up with the changing needs of industry.

NBS research in atomic spectrometry is focused on several different studies. For example, researchers are working to improve the analytical capabilities of the

direct current plasma (DCP) and the

inductively coupled plasma (ICP), as well as experimenting with the glow discharge

as an atom reservoir. Additional research concerns the use of spark sampling for the direct analysis of solids, the continued development of laser- enhanced ionization (LEI) in flames, and

the evaluation of various types of coupled chromatographic-spectrometric

systems for improving the accuracy of spectroscopic measurements. NBS scientists also are developing a

series of neutral density filters that can be

issued as Standard Reference Materials

for verifying the accuracy of the transmit- tance and absorbance scales of

ultraviolet, visible, and near infrared absorption spectrophotometers.

Contact: Robert L. Watters, B222

Chemistry Bldg., 301/975-4122.

Analytical mass spectrometry has played a key role in assisting industries, such as

the semiconductor industry, which

require accurate measurements of trace elements in their raw materials, products,

and product containers. Bureau research

in inorganic mass spectrometry is concerned with developing analytical

capabilities for the highly accurate deter- mination of trace inorganics by stable isotope dilution, the highly precise measurement of isotopic compositions, and

the highly accurate measurement of absolute isotopic compositions for the redetermination of atomic weights. This research involves development of instrumentation in spark source, thermal

source, inductively coupled plasma

source, and laser source mass spectrometry and research in chemical separations at the trace level using ion chromatography and other techniques.

Recently, electroanalytical chemistry has

had a key role in the development of methods and materials for environmental

and clinical determinations, in particular,

pH and conductance. While Bureau

research interests and activities include most areas of electroanalytical and classical chemistry, current emphasis is on

electrochemical detector development,

voltammetric and ion chromatographic

measurement methods, high-purity assay

by coulometric titration, potentiometric

measurements in biological fluids, and

fundamental studies and measurements

in pH and aqueous electrolytic conductance. NBS scientists are giving special

attention to the development of novel

electroanalytical instrumentation, including

computer interfacing. For all these

projects, instrumentation is available for accurate pH, potentiometric, coulometric,

conductometric, voltammetric, and ion- chromatographic measurements.

Contact: William F. Koch, A225

Chemistry Bldg., 301/975-4132.

More than 50 billion chemical analyses

are performed annually in the United

States. The Bureau helps to ensure the accuracy of these analyses by

developing new analytical procedures

and improving the reliability and

accuracy of present methods. One tech- nique under study is activation analysis,

which is a highly sensitive, nondestructive, analytical technique not normally

available in most industrial laboratories.

In this research, methods of nuclear analysis are investigated utilizing the 20-MW

NBS research reactor. Research is performed in all areas of the technique

including the capabilities of cold-neutron

activation, the use of sample self- consistent (monitor) activation, the deter- mination of new mathematical procedures

for the resolution of gamma spectra, the development of prompt gamma activation techniques, and the use of chargedparticle activation techniques.

Contact: Ronald F. Fleming, B108 Reactor

Bldg., 301/975-6279.

Inorganic

Electroanalytical

Research

Activation

Analysis

Contact: John D. Fassett, A21 Physics

Bldg., 301/975-4109.
Analytical Chemistry

Liquid

Chromatography/

Electrochemistry

Bioanalytical

Sensors

Liquid chromatography is one of the most widely used analytical techniques in industrial laboratories. While this tech- nique has achieved widespread application, its uses can be broadened even

further by improvements in detection methods. The focus of NBS research is the development of novel approaches for the electrochemical detection of organic

analytes separated by liquid chromatography (LC). To apply this technique most

effectively, it is essential to investigate the electrode reaction mechanisms of the compounds to be detected using tech- niques such as cyclic and reverse-pulse

voltammetry, coulometry, and LC/ultraviolet spectroscopy. Ongoing work

focuses on the use of differential pulse

and dual-electrode detection, as well as

the development of single and array microelectrode detectors. Researchers

also are developing new liquid chromatographic separations employing specific

chemical interactions including chelation,

ion-pairing, charge transfer complexation,

and acid-base equilibria.

Contact: William A. MacCrehan, A113

Chemistry Bldg., 301/975-3122.

Biosensors are the newest generation of analytical devices having the potential for widespread use in biomedical and industrial monitoring applications. These

devices will incorporate the latest advances in biotechnology to provide sensors of high specificity and sensitivity. Biologically derived substances have

important application as components of rapid-sensing devices because of their binding specificity, the strength of their interactions, and their potential for use in a wide variety of amplification schemes.

Immunological, enzymatic, and receptorligand interactions are being explored as

the basis for analytical devices. NBS researchers are employing a

variety of optical and electrochemical techniques for detection. Detection can be based on such diverse changes as

size and rotational mobility of analytes or binding agents upon interaction, or can be the result of enzymatic activity which

occurs due to analyte binding, causing

enhanced fluorescence or electrochemical signal. Amplification can be achieved

with release to liposome-encapsulated

molecules, multi-turnover enzyme reactions, ion-exchange polymer-modified

electrodes, and so forth. The combination

of high specificity for analytes with effi- cient amplification provides the potential

for extremely sensitive devices.

Contact: Richard A. Durst, A113 Chemistry Bldg., 301/975-3118.

Using a secondary ion mass spectrometry instrument, metallurgist Dale Newbury is able to map the distribution of ele- ments both on and below a sample's surface.

10
Analytical Chemistry

Supercritical

Fluid

Chromatography

Liquid

Chromatographic

Stationary

Phases:

Retention

Mechanisms and

Characterization

Supercritical fluid chromatography (SFC)

in both capillary and packed columns

has recently received renewed attention because the process offers several advantages over liquid and gas chro- matography for high-efficiency separations of nonvolatile molecules. Potential NBS research in this area would focus on the investigation of the variables that influence the retention, selectivity, and

efficiency of SFC systems and on the development of SFC as a useful analytical technique to provide high-efficiency

separations of complex mixtures. A

packed-column SFC is available and a

capillary SFC is being procured to make

state-of-the-art measurements. Auxiliary

spectroscopic detectors have and are being developed to complement this SFC

instrumentation.

Contact: Stephen N. Chesler, 301/975-

3102 or Stephen A. Wise, 301/975-3112,

A1 13 Chemistry Bldg.

Liquid chromatography (LC) on chemically bonded stationary phases (e.g., C18 , C8 , NH2 , and N02) offers unique capabilities for the separation of isomeric compounds or compound classes. However, significant differences in retention and selectivity characteristics, such

as relative retention, are observed among

commercial phases produced by different manufacturers and even within different batches prepared by the same manufacturer. One area of NBS research has been

directed toward understanding which

factors influence LC retention on these

various stationary phases to predict,

improve, and control the separation

selectivity. In reversed-phase LC on C18 phases, polycyclic aromatic hydrocarbons have been used as model

nonpolar solutes to study retention mechanisms and selectivity. Various

physical parameters of these solutes, including size, shape, aqueous solubility, and partition coefficients; characteristics

of the bonded phase such as phase

type, alkyl chain length, and ligand surface density; and mobile phase

characteristics have been studied to determine their influence on retention and

selectivity in LC. Investigations have

focused on both the physical and chro- matographic characterization of these

stationary phases.

A variety of methods are available at NBS for physical characterization of these

materials, including carbon analysis, gas

adsorption surface area techniques,

infrared and nuclear magnetic resonance

spectroscopy, and small-angle neutron

scattering techniques. Currently, Bureau

scientists are attempting to develop chro- matographic test mixtures to evaluate LC

stationary phase characteristics and chro- matographic performance. Such "performance" standards would allow the direct comparison of the various LC phases

produced by different manufacturers and

provide insight into the development of improved stationary phases for specific

separations.

Contact: Stephen A. Wise, A113

Chemistry Bldg., 301/975-3112.

Multidimensional (dual column) and very

high-resolution (> 100,000 plates) gas

chromatographic methods offer the

analyst an opportunity to perform difficult separations to facilitate species-specific

quantitation. These high-resolution tech- niques are being investigated at NBS to develop highly specific analytical proce- dures for the quantitation of ng/g organic

constituents contained in complex

environmental and clinical matrices. Research in this area focuses on the

optimization of multidimensional gas chro- matographic experiments in which two

capillary columns, each possessing

individual and different retention mechanisms, are serially connected by a pneumatic switch. In addition, studies center on the use and development of

tailored, very high-resolution capillary

columns. An independently controllable, dual-oven gas chromatograph is available

for multidimensional research. Additional

facilities and equipment include state-of- the-art sample preparation and gas chro- matography laboratories, 12 capillary gas chromatographs with multiple specific

and non-specific detectors, and a large

laboratory information management

system (LI MS).

Contact: Stephen N. Chesler, A113

Chemistry Bldg., 301/975-3102.

Multidimensional

and Very HighResolution Gas

Chromatography

11
Analytical Chemistry

Microbeam

Compositional

Mapping

Trace Gas

Measurement

Techniques

Interpreting the relationship between the

physical and chemical microstructure of materials is important in understanding

their macroscopic behavior and in extending their in-service performance.

Conventional microbeam techniques for elemental/molecular compositional analysis on the micrometer scale, such as the

electron microprobe and ion microscope,

have been restricted to quantitative analysis at individual locations. Mapping of the distribution of constituents has been

possible only at the qualitative or semiquantitative level. However, recent NBS

research developments have led to the production of the first true quantitative

compositional maps. Quantitative

compositional mapping with the electron microprobe has been demonstrated

down to levels of 0.1 weight percent, while quantitative isotope ratio measure- ment in images has been demonstrated

with the ion microscope.

Current research activities include extension of compositional mapping to analytical electron microscopy, laser Raman microanalysis, and laser microprobe mass analysis.

Potential projects in this field include applying the compositional mapping

instruments to materials characterization problems, developing new techniques for compositional mapping on other microanalysis instruments, and investigating basic topics in quantitative analysis with microbeam instrumentation. The equipment available for this activity includes a Cameca electron microprobe,

a JEOL analytical scanning electron microscope, a JEOL analytical electron microscope, a Cameca ion microscope,

a Leybold-Heraeus laser microprobe mass analyzer, two laser Raman

microprobes of NBS design, and extensive computer facilities, including a VAX

1 1/780 computer and a DeAnza image

processor.

Contact: Dale E. Newbury, B364 Chemistry Bldg., 301/975-3921.

Accurate measurement of gaseous

species is of paramount importance to a wide variety of industries in a number of applications ranging from the quantification of pollutant and toxic gas emissions

to the quality control of products. The

validity of data derived from such measurements is directly tied to the availability

of useful gas measurement techniques

and to the degree of understanding of

their capabilities and limitations. While a

variety of techniques have been applied

to trace gas analysis, research directed

at modifications, innovations, and

rigorous assessments of these and new

techniques is needed to improve the present state of the art in trace gas analysis. This research is particularly important to the growing requirements for the

analysis of specific gas species in multi- component gaseous mixtures and in the extension of accurate analyses to below

the parts-per-million and parts-per-billion

levels. Current NBS research is focused on

such trace gas measurement techniques as new detection systems using

chemiluminescence, electrochemistry,

infrared diode laser systems, capillary

gas-liquid and gas-solid chromatography

coupled to mass spectrometry, and

isotope-dilution mass spectrometry. Bureau scientists also are examining the use of class-specific detectors for gas chromatography and evaluating electronic circuitry to substantially optimize

signal and reduce instrumentation noise and drift.

Contact: Walter L. Zielinski, Jr.. B364

Chemistry Bldg., 301/975-3918.

A major task in the industrial production

of organic fine chemicals, drugs and

antibiotics, and biomolecules is the

characterization of the product for both compositional analysis and quality

control. Nuclear magnetic resonance (NMR) spectroscopy has proved to be a

powerful and widely used tool for these and related purposes. One NBS program in this area involves the development of new and improved

methods for the structural, quantitative,

and conformational analysis of materials

of chemical and biotechnological importance. The principal techniques that are being investigated include multmuclear,

two-dimensional NMR and its combination with multiple quantum methods and

distortionless enhancement by polarization transfer (DEPT). A specific goal of this work is the development of new two- dimensional spectrum editing and filtering techniques and their application to structural and conformational characterization

via correlations with multmuclear chemical shifts, coupling constants, relaxation

Nuclear Magnetic

Resonance

Spectroscopy of Bioorganics

12
Analytical Chemistry

Protein

Characterization

by TwoDimensional

Electrophoresis

times, and nuclear Overhauser effects. This work is conducted at NBS with a

high-field (400-MHz) multinuclear NMR

spectrometer equipped with a new pulseprogrammer (process controller), a highcapacity data acquisition system, an

array processor, and an off-line data processing station.

Contact: Bruce Coxon, A361 Chemistry

Bldg.. 301/975-3135.

NBS scientists are using a two- dimensional electrophoresis system to characterize proteins and peptides. At

present, they are probing the influence of

size, shape, and charge on the migration

characteristics in the electrophoretic

medium. Well-defined protein "markers,"

especially of high molecular weight, are

required to allow standardization of polyacrylamide gel electrophoretic systems.

Charged polymeric materials other than

proteins may be considered for markers. Because staining and detection of such

markers is of special interest, NBS

researchers plan to examine the mechanisms of silver stains with neutron

activation techniques.

Additional studies will be directed toward understanding the interactions of proteins with metal ions. Image

processing by state-of-the-art instrumentation will be implemented in the formation

of meaningful databases. As part of this program NBS plans to issue well- characterized mixtures of proteins as Standard Reference Materials (SRM's).

These new SRM's will be used to assess

the abilities of existing and new elec- trophoretic techniques for separating and

detecting proteins.

Contact: Dennis Reeder, A361

Chemistry Bldg., 301/975-3128.

Inorganic and organic compressed gas

mixtures are employed extensively

throughout industry to calibrate equipment used in assessing the quality of products and the effectiveness of emission controls. The stability of these

mixtures is critical to their successful use. A number of instances have been noted

in which instability has been observed,

particularly in mixtures containing low

levels of reactive gaseous species, such

as nitrogen oxides, sulfur dioxide, and

hydrocarbons. The explicit reasons for

instability may differ somewhat for different gaseous species, but they are

related to at least two possible

phenomena: gas-phase reactions and

gas-metal interactions with the internal surface of the cylinder.

NBS research is directed at improving

the understanding and predictability of both of these phenomena. The tech- niques involved in this research include those employed in surface science

studies and other approaches, such as

Fourier-transform infrared spectrophotometry, diode laser and other forms of spectroscopy, mass spectrometry, metal

analysis, trace water and oxygen analysis, chemiluminescence analysis, and

the use of specifically doped mixtures

and homogeneous gas phase kinetics.

Contact: Walter L. Zielinski, Jr., B364

Chemistry Bldg., 301/975-3918.

Instability of Compressed Gas

Mixtures

Research chemist Dennis Reeder is working to improve the accuracy of two-dimensional electrophoresis so biotechnology

companies can use the technique to assess their products'

purity. 13
Applied Mathematics

Computational Designing comprehensive software for Mechanics modeling and database applications in materials science and engineering is the

goal of this project. Current research on

computer-aided modeling of the behavior

of structural materials and components

ranges from microscopic feature analysis

of fatigue, fracture, phase change, creep, and polymer crystallization to the stresslife prediction of structural reliability of

critical components based on mechanical

and flaw-detection testing. In these

studies, NBS researchers are emphasizing the interplay among the choices of data representation,

appropriate physical principles, incisive mathematical and computational tools, and integrated software for graphics and

databases. In addition, they are

interested in mathematical theories of

elasticity, plasticity, viscoelasticity, and so

forth, as well as mathematical methods

using matrix theory, finite-element algorithms, bifurcation analysis, statistical distribution concepts and sampling

theory, and stochastic differential equations.

Contact: Jeffrey T. Fong, A302 Administration Bldg., 301/975-2720.

Mathematical analysis, in combination Nonlinear

with symbolic computation, leads to effi- Mechanics

cient analytical approximations by

computers. Perturbation algorithms

applied to nonlinear differential equations,

especially in celestial mechanics, result in analytical developments whose

complexity grows exponentially with the order of the approximation. Several

different avenues are being explored to simplify literal developments generated

by perturbation algorithms applied to nonlinear systems. These include the

identification of algebraic structures on

the domain of the normalization,

smoothing transformations to eliminate perturbation terms outside the kernel of the Lie derivative, preparatory transfor- mations of a geometric nature, and the

creation of natural intermediaries. Prob- lems currently under examination at NBS

are resonances at an equilibrium,

perturbed pendulums, and the major

theories of celestial mechanics. NBS

researchers, using a LISP computer, are focusing their exploration on algorithms

amenable to computer automation

through symbolic processors.

Contact: Andre Deprit, A302 Administration Bldg., 301/975-2709.

Measurement Quality assurance for physical and chemAssurance ical measurements and productivity

improvement in laboratory operations

depend on the development of new

statistical methods and models. Current

interests at NBS include experiment

design for calibrations, robust estimation, time-series analysis, and graphical analysis. In addition, multivariate problems

arise in the evaluation of complex electronic equipment. Therefore, estimation of variance components and of statistical tolerance limits for populations with several variance components are being

studied.

Contact: Mary G. Natrella, A337 Administration Bldg., 301/975-2854.

Multi-dimensional geometric represents- Computational

tions and data structures provide the Geometry

basis for developing algorithms, software,

and computer techniques used to describe, manipulate, and control objects

handled in an automated process. NBS

applications for this type of geometry

include manipulating objects in auto- mated design and manufacturing

systems and optimal control of machining

and mechanical processes. In addition,

techniques of computational geometry

are applied to computations with digitized

cartographic data and to the display of quasi-crystal structures with icosahedral symmetries.

Contact: Christoph J. Witzgall, A302

Administration Bldg., 301/975-2725 or

Sally E. Howe, A151 Technology Bldg.,

301/975-3807.

14
Applied Mathematics Basic Standards

Vector To make effective use of vector Algorithms and computers, new algorithms appropriate to Mathematical the special architecture of these Software machines need to be designed and

incorporated in high-quality mathematical

software for general use. Very successful vector algorithms have been developed

for computations in numerical linear algebra (e.g., computation of the discrete Fourier transform), but few are available

for combinatorial problems. One area of NBS research is concerned with developing vector algorithms appropriate

to the combinatorial problems encountered in molecular dynamics simulations,

in particular three-dimensional simulations

with very large ensembles of particles. Additional areas include methods for solving highly nonlinear elliptic and parabolic partial differential equations as well as nonlinear constrained and unconstrained optimization problems and the

solution of nonlinear systems of equations. NBS researchers also are working on the solution of integral equations and

numerical evaluation of integrals. Soft- ware development goals include port- able, interactive packages integrating

modern graphics with numerical

algorithms.

Contact: Francis E. Sullivan, A438 Administration Bldg., 301/975-2732.

Mathematician Sally Howe is developing algorithms and soft- ware for robot motion planning that will be used in the Bureau's Automated Manufacturing Research Facility.

There is currently tremendous interest in the growth of gallium arsenide (GaAs)

semiconductors on silicon substrates because such substrates can provide

excellent mechanical strength and

thermal properties that are not provided

by the GaAs material alone. A major diffi- culty with growing GaAs on silicon has

been the mismatch of lattice constants and the concomitant incorporation of defects. However, new studies show that a better match of the lattice xxx can be

achieved if the silicon substrate is cut at a small angle to the crystal plane. To

probe the interaction of relevant semiconductor materials with the silicon substrate,

NBS scientists are using sensitive, tunable laser sources to detect the

individual states of the atoms and

molecules as they interact with the growth substrate and growing material. Complete surface diagnostics and ultra- high vacuum conditions are used in this work. NBS researchers are determining

the sticking coefficients and adsorption

energies of the individual spin-orbit states

of gallium atoms and other dopant atoms

plus the effects of vibrational excitation of the arsenic dimers on the growth of GaAs semiconductor materials. Another Bureau study involves the deposition of thin films of amorphous

silicon, which are used in photosensitive

devices and in photovoltaic cells. Scientists are examining mechanisms involved

in silane discharge and thermal chemical vapor deposition (CVD) production of such films. Mass spectrometry is used to study gas discharge processes, gas

chemistry, and surface chemistry and

their effect on film growth, character, and

quality. Researchers are operating a

tnreshold-ionization mass spectrometer

that can detect H and Si x Hn radicals at densities of 1 part per million of the parent silane gases. The spectrometer

also has a threshold sensitivity in the neighborhood of 10 11 cm -3 in the reactor

vessel. All electronics, vacuum, and gas

handling apparatus necessary for examining rf and dc discharges and

thermal CVD under controlled conditions are available as is a pulsed laser for use

in studying surface species by laser blowoff.

Studies of Semiconductor

Materials

Contact: Stephen R. Leone, 303/497-

3505 or Alan C. Gallagher, 303/497-

3936, Div. 525, NBS, Boulder, CO

80303.

15
I

Basic Standards

Advanced AC Thermal voltage and current converters Voltage and offer the most accurate and broadband

Current method for measuring ac voltage and

Measurements current for applications in communications, power generation, aerospace, and

defense. Thermal transfer standards are

calibrated by NBS in terms of reference converters which have themselves been

characterized by reference to the NBS

primary standards. The primary stan- dards are a set of special multijunction thermal converters whose performance is known over quite limited ranges of current, voltage, and frequency.

Complex, bootstrap methods are used to extend the current, voltage, and

frequency ranges. However, because

uncertainties expand considerably in those regions remote from the primary

standards, NBS is studying new methods

and converter designs to reduce signifi- cantly uncertainty for these regions. Of

particular interest are voltages below 0.5 V at all frequencies and frequencies from

100 kHz to 1 MHz at all voltages. The

apparatus available for the studies includes the NBS primary standards with sub-part-per-million (ppm) uncertainty in a core region of parameter space and a number of high-accuracy comparators,

both manual and automated, with sub- ppm accuracy capability.

Contact: Joseph R. Kinard, 301/975-4250

or Norman B. Belecki, 301/975-4223, B146

Metrology Bldg.

Laser Many of the most sensitive and sophisti- Stabilization cated applications of lasers depend on

the laser's spectral coherence, frequency

stability, and low-intensity noise. For a number of years, NBS scientists have

been working on appropriate laser control techniques in the domain of laser

intensity stabilization, laser frequency

stabilization, linewidth reduction with active control techniques, and several methods for producing quantitative laser frequency scans. In the latter category

are two new systems. One, based on

optical sideband production by broad- band microwave phase modulation of the

laser, allows scans over a ±5-GHz range

with inaccuracy below 10 kHz. The other

scan technique utilizes a novel inter- ferometer/phase-locked rf system which

maps optical frequency change into corresponding phase change of an rf signal suitable for control, stabilization, and scanning. This system is intrinsically free of errors which accumulate over

large scans. In combination with a Lambdameter for coarse wavelength identifica- tion and a single absorption line used as

absolute calibration, for example, NBS

scientists can scan a few dozen

angstroms with sub-MHz accuracy. Another NBS system under development works entirely externally to a cw

laser to shift the output laser frequency

and reduce the intensity in a controlled manner. The first application of this is clearly a box which will sit in the output

beamline of any laser and "eat" both frequency noise and amplitude noise in the intrinsic output of the laser. Bureau

scientists have demonstrated this function by the combination of an external electro- optic phase shifter and an acousto-optic

frequency shifter, which also functions as

a fast controlled optical attenuator. Residual noise levels near the values

fixed by the fundamental quantum fluctu- ations have been achieved in laboratory

experiments.

Contact: John L. Hall, Div. 525, NBS.

Boulder, CO 80303, 303/497-3126.

X-ray spectroscopy can provide information on electronic structure and on the

local atomic structure of atoms in matter. Bureau scientists have constructed a

synchrotron radiation beamline at the

National Synchrotron Light Source which

provides the highest flux, highest intensity, and highest energy-resolving power

of any existing beamline in the x-ray energy range from 1 keV to 5 keV. NBS

equipment complements the synchrotron

radiation instrumentation. X-ray absorption spectroscopy techniques such as

x-ray absorption near edge structure (XANES) and extended x-ray absorption

fine structure have been used to deter- mine the atomic structure of metals, semi- conductors, polymers, catalysts, biological molecules, and other materials

of interest to industry. The Bureau has

additional experimental capabilities for

Study of Atomic

Structure of Matter with

X Rays

16
Basic Standards

Vacuum and

Leak Standards

x-ray emission spectroscopy, x-ray photoelectron spectroscopy, and Auger

electron spectroscopy, which are powerful probes of the electronic struc- ture of solids, liquids, or gases. The x-ray standing wave technique uses interference between incident and

diffracted x rays to determine the precise

location of impurities or imperfections

within a crystal or at its interfaces. The

technique can be used to investigate the

location of dopants and imperfections in semiconductors or optical crystals, growth of overlayers on crystals, and the

structure of catalysts supported on crystal substrates. In addition, evanescent x rays which penetrate only a few nanometers

from an interface can be controlled to study chemical composition in the vicinity of an interface. NBS scientists recently pioneered a new technique, diffraction of evanescent

x rays (DEX), which combines and

extends the capabilities of the x-ray standing wave method and experiments

based on evanescent x rays. The

synchrotron radiation beamline provides an ideal facility for applying these tech- niques.

Contact: Paul L. Cowan, 301/975-4846 or Richard D. Deslattes, 301/975-4841, A141

Physics Bldg.

A wide variety of industries depend on

accurate vacuum (pressure) and leak measurements for research and development and for process and quality control. As part of its program in basic standards,

NBS maintains, or is developing, pres- sure or vacuum standards from above

atmospheric pressure to ultrahigh vacuum and leak or flow standards from

10~ 3 to below 10~ 9 std cc/s. Facilities for this research include five UHV systems, two low-range flowmeters, high-accuracy

mercury manometers, pressure and vacuum control systems, and a variety of vacuum, electronic, data acquisition, and

data analysis equipment. These facilities and measurement capabilities are used

to develop improved measurement tech- niques and equipment and to investigate

Physicist Dieter Hils, at the NBS/University of Colorado Joint

Institute for Laboratory Astrophysics, conducts research in the

stabilization of laser systems to provide standard sources of monochromic optical waves. Such devices are of commercial

interest for many areas of industrial and scientific research.

the performance of vacuum and pressure equipment, including mechanical pres- sure gauges, momentum transfer gauges, ionization gauges, standard

leaks, and residual gas analyzers. In addition, NBS plans to use this measure- ment capability to investigate material properties and physical phenomena of fundamental interest.

Contact: Charles R.Tilford, A515 Metrology

Bldg., 301/975-4828.

17
Basic Standards

Frequency, Time, Advancements in communication and

and Phase Noise navigation systems require atomic oscil- Measurement lators with increased performance and

reliability. NBS has several programs

aimed at providing advanced frequency

standards which have the potential for benefitting commercial atomic standards. Bureau scientists are currently working on an optically pumped cesium-beam

standard which should significantly surpass the performance of standards based on magnetic state selection and

detection. Their studies on ion storage

and radiative cooling are probing the

potential for standards operating at accuracy levels of one part in 10 15 and

perhaps beyond.

Aerospace systems often require extreme phase stability, which has led to a need for high-quality phase noise

characterization amplifiers, frequency

multipliers, oscillators, and other elec- tronic components. Thus, NBS has

initiated a program to develop methods

for measuring phase noise in such

components over a broad frequency range (into the millimeter range). The

work will primarily involve the twooscillator technique, but other techniques

will be studied. Requirements for synchronization (time) and syntonization (frequency) of broadly

dispersed sets of nodes for communication, navigation, and other electronic systems are increasing significantly. Because of the inherent reliability, simplicity, and low cost of using satellite transfer, NBS is studying several possible

approaches for using this technique. The

excellent performance of the NBS Time

Scale and reliable ties to many other

international timing centers provide the

basis for analysis of the performance of these time-transfer techniques. In addition, the Bureau is equipped with GPS

receivers, Earth communication terminals,

and automated systems for statistical analysis of the performance of systems.

Contact: Donald B. Sullivan, Div. 724.03, NBS, Boulder, CO 80303,

303/497-3772.

Precision voltage standards based on Solid-State DC

solid-state references are finding Voltage

increasing use in dc voltage metrology, Standards

particularly in the design and support of high-accuracy digital voltmeters and auto- mated test equipment. To improve the

quality of these standards, Bureau scientists are carrying out a research program

on Zener diodes and similar devices. They are investigating device properties

such as temperature coefficient, short- term noise, long-term stability, and perfor- mance under temperature shock and

power interruption. The aim of these

evaluations is to identify devices suitable

for a rugged 10-V transportable standard capable of providing sub-part-per-million

(ppm) accuracy when used as a trans- port standard between laboratories. The

effects of temperature extremes, physical

shock, and shipping delays on diode

output is of special interest.

In another area of research, NBS is producing a stable 1.018-V output

derived from a solid-state reference. The

researchers are specifically interested in the design and manufacture of low-noise, stable resistors that are immune to temperature shock and power interruption. Facilities are available to test Zener

diodes with 0.1 -ppm resolution and to manufacture both bulk metal foil and

wire-wound resistors. Detailed study of the dependence of device performance on fabrication parameters is possible

through high-accuracy measurements

referenced to national standards and

collaboration with Bureau scientists in several NBS divisions on the fabrication

of Zener devices.

Contact: Bruce F. Field, B258 Metrology

Bldg., 301/975-4230 or Norman B. Belecki, B146 Metrology Bldg.,

301/975-4223.

High-precision mass measurements on Automated Mass

mechanical balances in industrial stan- Measurements

dards laboratories are now very slow and

labor intensive. Since fully automated mass measurement systems are not yet commercially available, the NBS mass

program is developing a low-cost modular system. It will include a balance

beam servo-system for automatic data

acquisition; automatic modules to probe

18
Ik

Basic Standards Building Technology

Temperature

Sensor Research

air temperature, pressure, and relative humidity; a thermal "weight-soaking" plate

servoed to the temperature of the balance chamber; a robotic weightchanger that can accommodate multipleweight combinations; and integrated soft- ware to control the measurement process and analyze the data with the NBS mass

code. Many of these concepts have

already been incorporated into a trans- portable mass measurement assurance package that is now being tested in industrial and state metrology laboratories. A fully automated system will not only reduce the labor cost of mass measurements, but will also minimize the operator and environmental biases that enter the manual measurement process.

Contact: Randall M. Schoonover, 301/975-

4216 or Robert D. Cutkosky, 301/975-

4214, B160 Physics Bldg.

Improved industrial processes and

sophisticated scientific research require

temperature sensors that cover wider

temperature ranges with better accuracy and precision. For example, the degradation of thermocouples exposed to high

temperatures for extended periods of time represents a serious impediment to temperature measurements in jet engines, furnaces, and so forth. NBS has

several projects under way to test and

improve the performance of currently

available sensors. These sensors include thermocouples, platinum resistance ther- mometers, and a variety of cryogenic

temperature transducers. The temperature range covered by these projects

extends from cryogenic temperatures

(0.005 K) to about 1500 °C. For this research, the Bureau has excellent temperature calibration facilities, an auto- mated laboratory equipped to evaluate thermocouples at high temperatures,

several laboratories equipped for work on

platinum resistance thermometers, and

cryogenic laboratories where measure- ments can be made in the millikelvin range. NBS scientists are planning a

series of studies of new materials, new

principles, and new techniques to provide uniform and accurate temperature measurements.

Contact: Robert J. Soulen, B128 Physics

Bldg., 301/975-4801.

In a strongly computer-oriented program, NBS researchers are seeking to develop an improved understanding of the rela- tions among the chemistry, microstructure, durability, and other factors that

affect the performance of cement,

concrete, and other inorganic building

materials. Current areas of research

include mathematical modeling of the development of microstructure in cement

hydration and of the effects of microstructure on cracking of concrete; investigations of mechanisms of materials degradation; and development of artificial intelligence systems for optimizing the

selection of building materials. Bureau

scientists are conducting analytical and

experimental research on cracking and

the dynamic properties of concrete and

other brittle building materials. They are performing chemical and microstructural studies using a variety of techniques,

including light microscopy, scanning

electron microscopy, x-ray diffraction, and thermal analysis.

Cement hydration research contributes

to making concrete a more predictable

material. Therefore, NBS is seeking

fundamental understanding of portland

and related cements and their reactions

with water by developing and validating

mathematical models based on plausible reaction mechanisms, taking into account such processes as diffusion, nucleation,

and growth of new phases. The models,

which will probably be run on a Cyber

205 computer, will predict the courses and kinetics of the many reactions taking

place during cement hydration and the development of microstructure under a wide range of conditions. Special

experimental techniques employed in studying the reactions of cements

include, in addition to the techniques

mentioned above, microcalorimetry, pore

solution analyses, ion chromatography,

and Fourier transform infrared spectroscopy.

Contact: James R. Clifton, B348

Building Research Bldg., 301/975-6707.

Cement and

Concrete

Experimental and analytical research is under way at NBS to develop design

criteria for steel and masonry structural components subjected to dynamic loads such as winds and earthquakes. The

work involves identifying limit states and

Structural

Engineering

19
Building Technology

This computerized large-scale structural test facility is used to

test the performance of full-scale bridge and building components during earthquakes.

establishing criteria to ensure structural

safety. In the laboratory, NBS

researchers use a unique computercontrolled test facility that can impose

forces and/or displacements in three

directions simultaneously and a 12- million-pound capacity universal testing

machine capable of testing large-scale

structural components 60 feet tall. A

high-performance computer graphics

laboratory including a VAX computer

system and specialized graphics-based

finite element software is utilized for the

analytical work.

Contact: Charles G. Culver, B268

Building Research Bldg., 301/975-6048.

To aid in the creation of buildings that Illumination

operate more efficiently and better meet Engineering

user requirements, NBS researchers are

investigating the interaction between

building occupants and illumination/daylighting systems. The work includes developing criteria for illumination quantity and quality and determining the

effects of light source color and the color,

size, and shape of the object on the performance of visual tasks. In addition, the research involves evaluating both the

trade-offs and availability of daylightmg

as well as illumination controls and their interaction with building heating/cooling

systems. The "basic" research laboratory

consists of a multichannel electro-optical

system that allows light to be delivered to the human eye in an experimentally

reproducible manner, while the "applied" research laboratories provide a realistic environment for studying color rendering

(distortion) of energy-efficient lighting

systems.

Other research projects include

daylight prediction computer modeling

based on detailed simulation and

experimental measurements. Also, the Bureau has initiated an experimental

project to determine thermal interactions between lighting systems and HVAC

(heating, ventilating, and air-conditioning)

systems to provide improved design and

evaluation techniques from the standpoint

of energy effectiveness, luminous

efficacy, and life expectancy of the

lighting fixtures.

Contact: Belinda L. Collins, A313 Building

Research Bldg., 301/975-6456.

NBS researchers are studying techniques Indoor Air Quality

for measuring and modeling indoor and Ventilation

contaminants, specifically the effect of air Efficacy

leakage and ventilation systems on their levels and movements. NBS pioneered

the measurement science for air infiltra- tion by introducing the tracer gas tech- nique. Currently the program has

expanded into measurements and

computer simulation modeling of various indoor air contaminants, notably

formaldehyde and radon. Radon decay

and dilution processes have been

modeled, and several in-situ measure- ments are being undertaken to develop
Building Technology

techniques to minimize excessive buildup

of radon coming from the ground. Bureau researchers have investigated

formaldehyde emission rates from

pressed particle boards and other

building materials to validate a prediction

model developed by the Oak Ridge

National Laboratory. In addition, NBS is developing comprehensive computer

simulation models for predicting emission,

dilution, absorption, and convective

movement of contaminants in and

through buildings with a number of rooms. An advanced gas chromatographic mass spectrometer is used to measure and analyze many indoor

contaminants, especially the volatile organic compounds.

Contact: Richard A. Grot, B114 Building

Research Bldg., 301/975-6431.

An extensive program to determine the performance of heat-pump and other noncryogenic refrigeration-cycle systems

is under way at NBS in both the field and laboratory. The systems being

studied include electric-driven, heat- driven (adsorption cycle), and heat- engine-driven systems. An essential part

of this program is the development of analytical models that will predict the performance of systems under transient as well as steady-state conditions and

with single refrigerants and refrigerant mixtures. These models will be for specific systems, that is, engine-driven or

electric-driven, with or without storage, in specific applications such as different buildings and climates. These models will predict the energy performance with various parametric changes, including

component sizing.

RefrigerationCycle-System

Studies

Organic Building

Materials

As part of a program to increase the

usefulness, safety, and economy of building materials, NBS is conducting

basic and applied research to determine

the quality and predict the service life of organic building materials such as

protective coatings for steel, adhesives,

roofing materials, and plastics. Specific areas of basic research include advancing the knowledge of degradation

mechanisms, developing improved

characterization methods, and designing

mathematical models of the degradation

processes. The results of this research

are then used to derive stochastic models for predicting the service life of these materials. The stochastic models

have a basis in reliability theory and life- testing analysis. Bureau scientists are now using

computer analysis of infrared thermographic images for studying the rates of corrosion and the formation and growth

of blisters beneath opaque protective

coatings. They are also utilizing gel- permeation chromatography, gas chro- matography, and spectroscopy to study

the mechanisms of photolytic and thermal degradation of poly (methyl methacrylate). In both projects, reliability theory

and life-testing analysis techniques are used for predicting the service lives of the materials.

Contact: Larry W. Masters, B348

Building Research Bldg., 301/975-6707.

Contact: David A. Didion, B122 Building

Research Bldg., 301/975-5881.

Bureau researchers are devising and

improving methods for measuring the

heat-transfer performance of thermal insulation and other materials used in the construction of buildings. An essential part of this program is the development

of comprehensive analytical and mathematical models that will predict the performance of these materials under

transient and steady-state conditions of use. These models will be developed for individual materials and for combinations

of materials that are used in the design

and construction of building walls, windows, doors, floors, ceilings, and

roofs. The work is primarily of a laboratory nature, and excellent new facilities are in place for use in the program. They

include a line-heat-source, guarded-hotplate apparatus that can accommodate

specimens up to 15 inches thick with computerized control and data-logging

and reduction capabilities, and a

calibrated hot-box test facility to measure

simultaneously air, moisture, and heat

transfer characteristics through a full-size wall 10 feet high and 14 feet wide.

Contact: A. Hunter Fanney, B306 Building

Research Bldg., 301/975-5864.

Thermal

Insulation

21
Ceramics

Ceramic Sintering of ceramics is a complex

Processing process that involves the interaction of many different processing variables. The

influence of these processing variables on sintering cannot be determined simply

by measuring final density or some other end-point property. Chemical composition

of the ceramic powders is known to be

of major importance and, under certain conditions, can mask effects of most

other processing variables. As part of a program on ceramics, NBS scientists are

investigating the effect of trace levels of impurities using clean-room processing to produce, compact, and sinter ultrahigh

purity ceramics. Compositions will be

measured at different stages of the process using nuclear activation analysis

(gamma-ray spectroscopy). Results from

this program will enhance investigations

of other processing variables, including

particle size, shape, agglomeration,

compaction method, and atmosphere

under controlled composition conditions. Such data will lead to better models for microstructure evolution during sintering.

Use of predictive models, in conjunction

with other ongoing efforts to produce

unique compositions and phases, can

lead to new advanced ceramic materials, with unique microstructures and properties.

Contact: Edwin R. Fuller, Jr., A258

Materials Bldg., 301/975-5795.

Tribology of NBS is examining the wear and frictional Ceramics characteristics of advanced ceramic

materials with state-of-the-art wear test analysis methods. Studying hightemperature ceramics, especially the type necessary for ceramic heat engines,

requires new test procedures and tech- niques and standardized methodologies.

For such research, friction and wear tests may be performed over a wide temperature range with a controlled test environ- ment. Equipment is presently available at the Bureau to test ceramics from 20 to 1500 °C, and a unique high-temperature,

controlled-atmosphere ceramic wear test

facility that will produce temperatures up

to 1500 °C is almost ready for use. Bureau researchers are also investigating the control of friction and wear

by advanced lubricants and lubricant

transfer methods. Pre- and post-test analyses include wear debris analysis,

profilometry, and scanning electron microscopy (SEM). SEM facilities are used to examine wear tracks and debris.

Contact: Ronald G. Munro, A215 Metrol- ogy Bldg., 301/975-3671.

Imperfections in highly perfect crystals Electro-optic

typically limit their performance in high- Crystals

technology applications such as optical

communications and optical signal

processing. In particular, limitations in the

perfection of electro-optic and

photorefractive materials such as lithium niobate and bismuth silicon oxide have

severely inhibited the development of optical switches and modulators. Bureau

researchers are investigating crystal perfection at a unique, monochromatic

x-ray topography facility at the NBS/Naval Research Laboratory beamlines on the high-energy ring at Brook- haven National Laboratory's National Synchrotron Light Source. The information from current studies, conducted

jointly with growers of high-quality crystal,

is expected to improve substantially the

quality, and hence the performance, of these crystals.

Contact: Bruce W. Stemer, A329 Materials

Bldg., 301/975-6122.

Bureau scientists are conducting several Fracture of long-range programs on the fracture Ceramics

behavior of two types of ceramic

materials, ceramic composites and polycrystalline ceramics. The program in composites focuses on determining the

effects of the fiber/matrix interface on

fracture behavior of ceramic matrix composites. The fracture studies on polycrystalline ceramics are exploring the

effects of grain boundary compositions

and structure on strength and stress corrosion susceptibility as well as the

effects of phase transformations on the strength and fracture toughness of piezoelectric and dielectric ceramics.

Facilities for these programs include mechanical testing machines for tensile and compressive tests, a microindentation hardness tester, and an environmentally controlled apparatus utilizing double

beam configuration for environmentally

enhanced crack growth studies.

Contact: Stephen W. Freiman. A329

Materials Bldg., 301/975-5761

22
Ceramics

Materials

Bioprocessing

Utilizing microorganisms to extract extraneous materials is one goal the

steel, mining, minerals recovery, and

waste treatment industries have in common. Biological leaching is a low- cost alternative to expensive energy

processes. Therefore, NBS researchers

are investigating microbiological processes for iron ore and scrap steel beneficiation through biosolubilization of copper and phosphate/silicate minerals,

and bioprocessing -leaching and

recovery -of strategic metals by

mesophilic and thermophilic micro- organisms. To develop appropriate processes for each type of extraction, characteristics of such microorganisms must be understood. Thus, NBS is developing and analyzing nondestructive, surface molecular analysis methods

including microscopic absorption and

emission spectroscopies. In addition, Bureau scientists are using ultratrace molecular speciation methods for solution and gas phase chemical speciation of diagnostic products or intermediates (gas

and liquid chromatographs coupled with graphite furnace, flame photometric, and mass spectrometric detectors). Other

areas under study include engineering

designs, bioreactor systems, and

development of standards such as metal

sulfide Standard Reference Materials and

ore bioleaching test protocols.

Contact: Gregory J. 5637 or Frederick E. 301/975-5737, A329

Ceramic Powder

Characterization

Olson, 301/975-

Brinckman,

Materials Bldg.

Improved characterization of particle size, shape, and crystal chemistry of ceramic

powders is now recognized as important

to the development and production of high-quality ceramics for advanced tech- nological applications. To obtain precise

and reproducible measurements of particle characteristics, Bureau scientists are utilizing a variety of instrumental methods, including scanning electron microscopy with image analysis. Theoretical investigations and statistical analyses

of data are then used to compare the

results of the measurement methods.

The broad NBS program also includes development of x-ray diffraction tech- niques, reference materials and data- bases for characterizing ceramic starting

powders, and ceramic monoliths. Auto- mated x-ray diffraction instrumentation

with position sensitive detectors has the

potential for rapid, production-line characterization of both phase composition and

material properties of powders and

monoliths. Characterization includes determination of powder composition

(qualitative and quantitative phase and

chemical constituents), glass-to-crystalline

ratio, crystallite and particle size, residual

stress, lattice parameters, and thermal expansion. Special equipment available

for studying the relationships between

particle characteristics and processing

parameters includes SEM, STEM, DTA- TGA, furnaces with atmospheric control, three automated powder diffractometers

with high-temperature stage, coulter counter, BET, sedigraph, and particle- size classifiers.

Contact: Alan L. Dragoo, 301/975-5785;

Carl R. Robbins, 301/975-5786; or Camden

R. Hubbard, 301/975-6121, A258 Materials Bldg.

Techniques that probe the surface environment of powders during crystalli- zation and compaction are likely to yield

significant information on the link between observed reaction chemistry

and product quality. To this end, NBS is investigating Fourier transform infrared (FTIR) and electronic absorption/emission

spectroscopies for ceramic surface analysis. Two lines of research in progress

exemplify the Bureau's approach and

serve as models for further exploration.

One project involves silicon nitride powders from various sources that have

been examined by FTIR. Compositional

purity (Si-N/Si-0 ratio) and percent beta phase are easily assessed by this nondestructive technique. The other

project concerns a fluorescent tag that has been developed for the siloxy group. The complex formed between the tag

and SiO" on silica gel has been detected by epifluorescence microscopy imaging.

This technique is expected to be useful

in quantitating the chemistry occurring at crack tips in silica samples.

Contact: Robert A. Faltynek, 301/975-

5636 or Frederick E. Brinckman,

301/975-5737, A329 Materials Bldg.

Ceramic Surface

Analysis

23
Ceramics

Optical Films Bureau scientists are analyzing the rela- tionship between processing, structure, and properties of optical films grown by

electron-beam (e-beam) deposition,

e-beam coevaporation, and ion-assisted e-beam deposition. To support industrial development of new optical materials

with superior properties such as decreased porosity, decreased stress, greater index stability, and lower absorptivity, these researchers are studying the

evolution of film structure starting from

nucleation, growth, thin-film adhesion,

and thermal properties of films. Characterization capabilities include refractive index by m-lme spectroscopy and

channel spectra, thickness, absorption

coefficients by laser calorimetry, stress by

interferometry, thermal diffusivities by

photothermal radiometry, x-ray photoelectron spectroscopy, Raman spectroscopy,

extended x-ray absorption fine structure, x-ray diffraction, and electron microscopy. New areas to be pursued,

with impact on optical signal processing

technologies, are epitaxial growth and

modulated structures for light-guiding

optical films with enhanced electro-optic

and nonlinear optical properties.

Contact: Albert Feldman, A329 Materials

Bldg., 301/975-5740.

Ceramic Phase Ceramic phase equilibria studies at NBS

Equilibria involve complementary research activities

in experimental, theoretical, dataevaluation, and compilation aspects of ceramic phase equilibria. These studies include all classes of inorganic materials except alloys. The data-evaluation and

compilation work is carried out under the

joint American Ceramic Society

(ACerS)/NBS program to provide industry

and others with a comprehensive data- base of up-to-date, critically evaluated phase diagram information. The established, broad-based, funda- mental and applied high-temperature

chemistry research program examines

chemical phenomena temperatures from 25 to above 5000 °C, atmosphere pres- sures from 10"10 to 20 atm, and

multicomponent solid, liquid, and vapor

systems. New or improved measurement

techniques are needed for identification and quantification of species and components present under these conditions.

Furthermore, transitional species, such as

clusters of atoms or molecules, present a

particularly unique measurement chal- lenge. Researchers need to measure

such species to be able to understand

condensation and surface phenomena on

a molecular-level and to develop

materials with unique structures and

properties. In addition to experimental

work, the research involves computer

modeling to extend the laboratory-based data to industrial-process conditions.

Contact: John W. Hastie, A329 Materials

Bldg., 301/975-5754.

Bureau scientists are investigating low- Ceramic

temperature synthetic approaches to both Chemistry

oxide and non-oxide ceramic powders

and the use of neutron and x-ray scat- tering expertise in atomic and microstructural studies. Special emphasis is placed on the use of novel chemistry and tech- niques to solve the problems of generating homogeneous, multicomponent

materials with predictable properties. In general, systems currently under study

include barium polytitanates, zirconia- toughened aluminas, and silicon carbidetitanium carbide particulate composites.

These researchers are examining the molecular structure of species in multicomponent alkoxide systems, the

kinetic aspects of sol-gel reactions, and

to the microstructure of product powders

and glasses. These studies were under- taken to define key process variables and guidelines for developing practical

sol-gel processes. Coupled with powder

synthesis and subsequent compaction is the development of in-situ measurement

techniques, including small-angle neutron and small-angle x-ray scattering. Such

techniques will allow characterization of key fundamental parameters controlling

early stages of the material processing.

This effort complements nondestructive

evaluation (NDE) sensor development so

that industry will be able to detect flaws

at the very early stages of processing

where the raw material can be recovered

and treated.

Contact: Kay A. Hardman-Rhyne, A329

Materials Bldg., 301/975-6103.

24
Ceramics Chemical Engineering

High-Temperature

Reliability of Structural

Ceramics

The success of structural ceramics in high-temperature applications, such as

heat engines or heat exchangers,

depends on the reliability of these

materials at temperatures that approach

their thermal limit. Because creep- induced cavitation is the primary cause

of failure at these temperatures, the

characterization of nucleation, growth,

and coalescence processes associated

with cavitation is essential to establish long-term reliability. Bureau scientists are studying basic processes associated with creep cavitation on a variety of ceramic

materials. To develop techniques for predicting component lifeti'me, they are

relating damage accumulation during creep to mechanisms of creep and

creep-rupture. This research includes creep and creep-rupture measurements

at temperatures as high as 1600 °C, and

the use of transmission electron microscopy to evaluate modifications in the microstructure that result in the generation of strength-limiting defects.

Contact: Sheldon M. Wiederhorn, A329

Materials Bldg., 301/975-5772.

Improved energy and manufacturing effi- Separations

ciencies could result from using various techniques to separate and recover

desired products from fluid chemical

mixtures. To improve separation procedures, the Bureau is creating a science

base for a variety of separations. As part

of this project, scientists are working in three rather diverse areas. One project involves the aqueous two-phase parti- tioning of proteins and biomolecules,

including measuring mass transfer characteristics and diffusion coefficients and developing mass transfer correlations

for classes of biomolecules. In another

project, NBS researchers are studying

membrane separations of carboxylic and

amino acids from reaction products and

waste streams using ion exchange

membranes. This research includes separating organic compounds from

polar solvents and developing models for the transport of weak and strong electrolytes through cation exchange columns.

Work in these two areas is expected to impact the commercialization of products

in the burgeoning biotechnology industry.

In a third study, Bureau scientists are separating gas using novel/efficient separation methods such as facilitated trans- port through liquid membranes, while conducting complementary modeling

activities. They are currently working on

acid-gas separations using ion exchange

membranes.

Contact: Subhas K. Sikdar, 303/497-5232;

J. Douglas Way, 303/497-5298, or Richard

D. Noble, 303/497-3416, Div. 773.10, NBS,

Boulder, CO 80303.

Research chemist Joseph Ritter (left) and physical science

technician Norman Adams are shown with the reactor they

designed for synthesizing advanced ceramic powders at low

temperatures.

Thermophysical properties data are

essential for the design and operation of many chemical processes such as supercritical extraction. To obtain these data,

NBS scientists are using three new phase

equilibria apparatus for studies at elevated temperatures. One has been

used to perform VLE measurements on carbon dioxide-hydrocarbon systems and

refrigerant-hydrocarbon systems, the second is a dew/bubble point apparatus

extending to 800 K, and the third employs a palladium-silver membrane to measure the fugacity of hydrogencontaining mixtures. Four exceptional instruments are available for making PVT,

PVTx, and heat capacity measurements

Properties of Fluids

25
Chemical Engineering

Radio Frequency

Wave Diagnostics

of Disperse

Systems

on pure fluids and fluid mixtures: an

isochoric PVT apparatus, a combined

Burnett/isochoric PVT apparatus, a magnetic suspension densimeter for PVT

and PVTx measurements, and an instru- ment to measure constant volume heat

capacity. In addition, an apparatus for sound speed measurements is available. Bureau researchers are also devising

techniques to characterize fluids and fluid mixtures when the temperatures, pressures, and times involved can result in reactions during the measurement

process. Included in this work is a well- equipped analytical laboratory and

specialized apparatus to study reactions.

Contact: Thomas J. Bruno, 303/497-5158;

James E. Mayrath, 303/497-3553; William M. Haynes, 303/497-3247; or Gerald C.

Straty, 303/497-3502, Div. 774.03, NBS,

Boulder, CO 80303.

The successful processing of paper pulp,

flour, coal slurries, and sludge depends

on accurate measurements of the percent of solids suspended in water in a

pipeline. To help improve these measurements, NBS is studying the propagation

of radio waves inside a conducting pipe

filled with complex materials. One result of this research has been the successful measurement of the solids fraction in a two-phase water-solid slurry. This was

accomplished by measuring the wavelength and attenuation of radio waves in a pipeline utilizing a 32-element antenna

array placed along the axial direction. From the known frequency and wavelength the speed of the radio wave, and

hence the dielectric constant, can be

deduced. By then applying a mixing rule and the dielectric properties of the

individual components researchers can

determine the solids fraction in a slurry. NBS is extending the project to incorporate systems with axially varying dielectric constants such as adsorption columns

and settling suspensions. Other measure- ments such as polarization rotation in a

swirling slurry flow and Doppler shifts due to fluid flow are being planned.

Contact: Adolfas K. Gaigalas, 109 Fluid Mechanics Bldg., 301/975-5941.

The accelerating costs of scarce fluid resources- particularly gas-are

producing increased concerns about the performance levels of gas meters. For these reasons, improved flow measure- ment traceability needs to be established and maintained so that realistic, quantified data are generated on a continuing

basis to assure practical gas measure- ments at satisfactory specified levels of performance. To achieve the desired flow measurement traceability, the Bureau is designing transfer standards to link the performance of calibration facilities to appropriate national reference standards. As part of this program, NBS researchers

plan to develop a fluid measurement

transfer standard and evaluate its perfor- mance. Because of the importance of these measurements, transfer standards need

to be designed so that high levels of confidence can be placed in them and

their performance. The new transfer stan- dards will be rigorously evaluated against

NBS gas flow calibration standards. This evaluation phase of the proposed

program will involve the appropriate range of calibrations to be done on the developed standards so that perfor- mance levels can be assured at specified

levels.

Contact: George E. Mattmgly, 103 Fluid Mechanics Bldg., 301/975-5939.

NBS researchers are gaining a fundamental understanding of chemical processes in fluidized bed reactors in the areas of bioprocessing and advanced

optical measurements at high temperatures. Their work in bioprocessing is aimed at improving the design and operation of liquid fluidized-bed and

expanded-bed bioreactors for industrial fermentation processes. To demonstrate

the feasibility of monitoring biofilm development in fluidized-bed fermenters. they plan to investigate the effects of hydrodynamics on the development and

detachment of immobilized-cell layers from individual carriers, and the effects of these layers on carrier-particle

hydrodynamics, using magnetically

suspended spheres and other tech- niques.

Flow

Measurement

Transfer

Standards

Fluidized Bed

Reactors

26
Chemical Engineering

Thermophysical

and Supercritical

Properties of Mixtures

Research in the high-temperature area

is based on a fluidized-bed reactor that is being adapted for advanced in-situ optical measurements at temperatures up

to 1150 °C. The principal advance

beyond the state-of-the-art probing of flu- idized beds has been the design of an

optical probe that allows observations at one or more arbitrarily chosen locations

in the interior of the bed. Presently, NBS

is interested in studying solids movement

in fluidized beds based on the fact that a

burning particle generates a distinct signal as it arrives at an optical probe

location. The goal of this work is to advance the understanding of the mixing

problem in multiphase chemical

processes.

Contact: Andrej Macek, B312 Physics

Bldg., 301/975-2610.

Chemical process technology requires an

accurate knowledge of various ther- mophysical properties of pure, polyfunctional chemicals and their mixtures. NBS

scientists conduct research on the most

important of these properties-equilibrium

phase composition, density, and

enthalpy. One NBS project deals with developing predictive methods for the

properties of chemically dissimilar compounds. Of special interest are those compounds found in gas and coal processing as well as chemical systems. Bureau researchers are planning related experimental phase equilibria studies. A second project is a combined

experimental and theoretical study aimed

at developing accurate predictive models

for the thermodynamic and transport

properties of supercritical solvent

mixtures. The work includes PVTx and

VLE measurements on mixtures

containing carbon dioxide, halogenated

hydrocarbons, and similar supercritical solvents. Other experimental work

includes the use of supercritical chro- matography to measure diffusion coeffi- cients in supercritical mixtures while

theoretical studies focus on the application of extended corresponding states to supercritical systems.

Contact: James F. Ely, 303/497-5467;

Joseph W. Magee, 303/497-3298; or Thomas J. Bruno, 303/497-5158, Div. 774.03, NBS, Boulder, CO 80303.

Through the use of very thin films and detailed surface

analysis, physicist Stephen Semancik and his colleagues have

characterized the surface adsorption properties of tin oxide. Such information can be used to improve tin oxide sensors.

To understand performance of thin-film and chemical sensors, NBS is performing

experimental and analytical research

related to these types of sensors. Such

studies are expected to improve the accuracy, stability, selectivity, and

response of chemical sensors and to stimulate ideas for entirely new measure- ment techniques. The Bureau's activities incorporate adhesion, oxidation, inter- laminar diffusion, surface adsorption and

desorption, and phase morphology to uncover mechanisms of chemical

sensing. Analytical methods relate the

structure and composition of sensing

devices to fabricating parameters and

performance. Sensors include thin-film thermocouples, fiber optic thermometers,

thin-film resistance devices, moisture

sensors, pH sensors, and gas detectors. Fabrication facilities include rf and dc

sputtering for both alloy and reactive film deposition and gas reactors.

Chemical Sensor

Research

27
Chemical Engineering

Optical Sensing

in Bioreactors

To determine the feasibility of thin-film systems as chemical sensors, NBS scientists are investigating the electronic properties of sputter coatings including

dielectric strength, surface conductance,

and capacitance. To examine surfacesensitive techniques, they are employing

x-ray and uv photoemission, thermal desorption spectroscopy, SIMS, and in- situ electrical measurements to characterize appropriate chemisorptive systems.

Contact: Kenneth G. Kreider, 301/975-

2619 or Stephen Semancik, 301/975-

2606, B312 Physics Bldg.

Recent advances in molecular biology

have led industry to recognize the potential benefit of applying these advances in a diversity of industrial sectors, such as

the production of new drugs, food additives, and chemicals and conversion of biomass. However, implementation of these new technologies requires meas- urement capabilities which do not

currently exist. Bioprocesses require a

very closely controlled environment,

normally realizable only in batch

processes. This is mainly due to the complex kinetics of most bioreactions,

separate periods of growth and product

formation, biocatalyst degeneration,

contaminant risks, and mechanical

difficulties of handling rheologically

complex material. Therefore, develop- ment of new on-line measurement tech- niques is critical for future implementation

of bioprocesses. Furthermore, nonintrusive measurement methods are desirable

to avoid difficulties associated with sampling, contamination, and long response time. To help solve some of these problems,

NBS scientists are developing optical

techniques, especially with the use of tunable lasers, for making nonintrusive,

rapid, and selective measurements. The

use of fiber optics also permits the development of probes which are steriliz- able, can provide measurements with good spatial resolution, and can be

multiplexed to provide multipoint

monitoring capability. Laser-induced

fluorescence is being used to determine

characteristics of ammo acids, dipeptides,

polypeptides, and esters while Raman

and resonance Raman scattering will be

utilized to provide more species and

selectivity. Fluorescence techniques are

also expected to provide a powerful tool

for cell activity and intracellular kinetics measurements.

Contact: Hratch G. Semerjian, B312 Physics Bldg., 301/975-2609.

To minimize the cost of high-price fuel, U.S. industry wants to obtain maximum

energy output from fuel combustion. Bureau researchers are tackling this problem by attempting to improve

combustion efficiency. To investigate

droplet vaporization, pyrolysis, combustion, and particulate formation processes and to delineate the effect of chemical

and physical properties of fuels on the above processes, they are studying the dynamics of spray flames. Results of this study will provide an experimental data- base, with well-defined boundary conditions, for developing and validating spray combustion models. The experiments are being carried out in a spray combustion

facility, with a moveable-vane swirl burner, which simulates operating conditions found in practical combustion

systems. A combination of nonintrusive probing techniques is being used to obtain comprehensive data on the spray combustion characteristics, including soot

particle and droplet size, number density

and volume fraction, gas composition,

and velocity and temperature fields. Currently Bureau scientists are focusing

their efforts on laser scattering and laser Doppler velocimetry measurements,

which are being used to determine the

correlation between droplet size and

velocity distributions, respectively, in both low-temperature and burning sprays.

Contact: Hratch G. Semerjian, B312 Physics Bldg., 301/975-2609.

Particulate and

Droplet

Diagnostics in Spray Flames

28
Chemical Engineering Chemical Physics

Properties of A wide array of experimental and theoret- Interfaces ical tools are being applied to obtain

practical and fundamental understanding

of the structure, properties, and effects of interfaces between fluid phases. NBS

scientists are studying a number of problems in this area ranging from the conceptually simple to measure and/or

calculate the interfacial tension between a

liguid and its vapor, to more complicated ones such as the phase behavior of surfactant mixtures at water-air interfaces, the thicknesses of adsorbed liguid layers

at solid-gas interfaces, the stability of foams, and the evolution of mists. Bureau

facilities include an automated ellipsometer and an automated film balance,

quasielastic light scattering for studying

the evolution of mists, an apparatus for measuring foam stability, and simple

setups for measuring interfacial tension. Computing facilities include a CDC 855, a Cyber 205 vector processor, software,

and experience in simulation of fluids. Bureau scientists are planning research

in several areas. One project will involve applying quasielastic light scattering to the measurement of interfacial tension of liguid-vapor mixtures at high pressure and the measurement of the dynamics of wetting layers. Another project will focus on measuring the permeability, surface

viscosity, and surface diffusion coeffi- cients of surfactant layers. In addition, the researchers will test NBS theories devel- oped for the large increase of the surface

tension of a liguid-vapor interface when it forms in a confined geometry (such as in a pore within a pellet) and for the large

effects of ions on the thicknesses of adsorbed layers. They will also study the

evolution of the drop size distribution of simple, but non-trivial, mists comprised of two hydrocarbons suspended in their own vapor.

Contact: Neil Olien, 303/497-3257, Div. 774, NBS, Boulder, CO 80303

The study of chemical kinetics at NBS

has numerous applications, including

controlling and monitoring environmental

pollution, of interest to industry, energy,

defense, and standards experts. Bureau

scientists have been determining the

kinetics and thermochemistry of industrially important organic molecules, molecular ions, and free radicals. Polycyclic aromatic compounds are important as reactants in coal-conversion processes and as products in virtually all pyrolytic reactions of organic substances. Facilities are available at NBS to determine the elementary rate constants and

mechanisms for reactions which control the formation and destruction of aromatic

compounds at elevated temperatures.

These facilities can be used to study

reactions involving polyaromatic free radicals in a variety of physical environ- ments including high-temperature liquids, very low-pressure gases, and graphite

surfaces. Complementary theoretical investigations also are possible. Other

research involves the thermochemistry of ion-neutral interactions using variable temperature, high pressure, and ion cyclotron resonance spectrometry. In addition, a new laser laboratory incor- porating the technique of multiphoton

ionization mass spectrometry is available

for state-of-the-art detection of free radicals- particularly biradicals. Other

chemical dynamics studies can be

carried out using picosecond spectroscopy.

Chemical

Kinetics and

Thermochemistry

Contact: Stephen E. Stein,

try Bldg., 301/975-2506.

A147 ChemisTo evaluate the properties of important

biological building blocks such as

proteins and nucleic acids, NBS recently

began biothermodynamics studies to evaluate existing thermodynamic data. Biomolecule crystals, which can be puri- fied and grown at the Bureau, can be

examined by x-ray and neutron diffrac- tion techniques for single crystals. NBS researchers have developed

quantum chemical computation tech- niques to calculate how complex systems

of organic molecules interact with metal

ions in metalloenzymes. Computing facili- ties include an IBM 4381, an Evans and

Sutherland color graphics system for model building, and the NBS Cyber

Biotechnology

29
Chemical Physics

Using experimental data and sophisticated computers, physicist Irene Weber maps the detailed chemical structure of biomolecules

to determine how they can be tailor-made to carry out specific reactions.

Surface

Characterization

855/205 supercomputer. In addition, the thermochemistry of enzyme-catalyzed

systems can be studied using a variety of calorimeters including micro-calorimeters designed and constructed at NBS.

Contact: Stanley Abramowitz, B348

Chemistry Bldg., 301/975-2586.

Surface characterization is now an

integral part of many technologies and

industries such as catalysis, coatings,

corrosion, semiconductors, computers,

automobiles, and communications. The

Bureau has several surface characterization facilities available, including the use

of synchrotron radiation at the NBS

synchrotron ultraviolet radiation facility (SURF II) and at the Brookhaven National Synchrotron Light Source. A full comple- ment of surface spectroscopies are available at SURF II and in other NBS

laboratories. These can be used to identify molecular species and structures on

surfaces. In addition, reaction chambers

are connected to some for investigation

of surface composition and catalytic reactions. New atom probe field ion micro- scopes offer high-resolution surface and

depth-profile analysis capabilities. Moreover, spectrometers are available at the NBS reactor to perform neutron inelastic scattering and time-of-flight experiments. Neutron scattering is used to study high- area catalytic materials under high- pressure reaction conditions. The sensitivity of this technique to hydrogen makes

it particularly attractive for industrial chemical process studies.

Contact: Cedric Powell, B248 Chemistry

Bldg., 301/975-2533.

30
Computer Sciences and Technology

Personal The personal computer has become an Computer omnipresent element in today's business

Security and scientific environment. However, as more sensitive and critical information is processed and stored on such systems

there is an increasing need for methods

to protect that information against

unauthorized access or modification. The

selection of information security measures, however, should be based on

an analysis of the cost of such measures

and the resulting reduction in losses. NBS researchers are investigating various technologies that can be employed to achieve additional control and security of information on personal computer

systems. Their research involves the

identification, analysis, development, and

application of these technologies.

While it is desirable to have security

mechanisms as an integral part of computer systems, this is not always

possible or economical because such

mechanisms are often not part of the

original system design. Therefore, NBS

researchers also are examining the tech- nology available to enhance the security

of existing systems. This research

involves identifying, analyzing, and

comparing security mechanisms used in isolation or combination.

Contact: Allen L. Hankinson, B266 Technology Bldg., 301/975-3289.

Database Testing To improve the management of information resources, NBS researchers are developing test methods and techniques

to be used in evaluating implementations

of network database language (NDL),

structured query language (SQL), infor- mation resource dictionary system (IRDS),

and data descriptive file (DDF) for confor- mance to the emerging federal, national, and international standards. Researchers

will attempt to derive a general methodology for designing conformance tests, to use this methodology to generate test suites, and to evaluate the test suites for effectiveness. A prototype implementation

of the IRDS specifications will be used in this project. It may be suitable for such

tasks as modeling the structure of a stan- dard and for recording what parts of a standard are tested by specific tests.

Contact: Alan Goldfine, A266 Technology

Bldg., 301/975-3252.

To help protect data communicated

through computer networks, NBS

researchers are developing protocols for secure key distribution and secure data

transmission using public key algorithms.

The protocols will protect keys from initial generation to final distribution to all authorized parties. In designing the

protocols, researchers will give special

attention to preventing substitution of the keys by unauthorized parties. The

protocols will also transmit keys and data

within a large computer network with automated communications capabilities.

And they will be consistent with those

used in the Open Systems Interconnection Reference Model. The project results

will be the basis for an NBS publication on public key cryptographic protocols.

Contact: Miles E. Smid, A216 Technology Bldg., 301/975-2938.

In the area of global communications,

NBS researchers are attempting to define present and future data communication

applications; performance metrics; and

characteristics of satellite channels, public data networks, and local area networks.

In addition, they will develop simulation and analytical models to permit perfor- mance predictions for open systems

protocol end systems and various subnetworks. Through various simulation experiments and analytical calculations,

NBS researchers will identify areas worthy of future investigation via live experiments. These live experiments will be performed to verify the significant simulation and analytical results.

Contact: John F. Heafner, B217 Tech- nology Bldg., 301/975-3618.

NBS is pursuing the development of several graphics standards and is working on related conformance testing

and measurement techniques for graphics software. Specifically, Bureau

researchers are testing the implementation of the graphical kernel system (GKS).

the computer graphics metafile (CGM),

GKS for three dimensions, and the programmers hierarchical interactive graphics standard (PHIGS) for confor- mance to the existing and emerging

federal, national, and international stan- dards. The researchers are attempting to

Public Key

Cryptographic

Protocols

Global

Communications

Computer

Graphics Testing

31
Computer Sciences and Technology

derive a general methodology for designing conformance tests, to use this methodology to generate test suites, and

to evaluate the test suites for effective- ness. In these studies, they are using the computer graphics laboratory, which

contains various computer graphics hard- ware and computer graphics software systems designed to support standard

specifications. An existing test suite for GKS is now available with a FORTRAN

interface. Priority is being given to testing

methodologies and test suites for PHIGS,

CGM, and the conversion of FORTRAN

tests for all computer graphics standards

to other languages (C, PASCAL, and

ADA).

Contact: Mark W. Skall, A265 Technology

Bldg., 301/975-3264.

Software National and international standards

Engineering groups are working on standards designed to reduce software engineering

problems. As part of this effort, the Bureau has been working on specifications for documents representation. The

principal specifications are the office document architecture (ODA) and the standard generalized markup language

(SGML). NBS researchers are also

striving to adopt a Federal Information Processing Standard (FIPS) for UNIX- based operating system environments. In this project, work is centered in three major areas: development of the technical description of the standard; development of guidance for federal agencies on implementation of the stan- dard; and identification of test methods

for testing conformance to the standard.

In addition, NBS is evaluating

emerging software engineering workstation technology, specifically the use of stand-alone and interconnected workstations for requirements analysis and

design, prototyping, verification, and

testing.

Contact: Allen L. Hankinson, B266 Tech- nology Bldg., 301/975-3289.

SCSI Verification Standards development is just the first step toward compatibility of computer

products. Test and measurement

methods are essential for ensuring that

products and systems meet the increasingly complex standards. At NBS

researchers are setting up a laboratory in which procedures for verifying the confor- mance of computer storage peripherals

to the Small Computer System Interface (SCSI) standard, X3. 131 -1986, can be

developed. The laboratory is being

equipped with a variety of SCSI diagnostic tools and peripherals.

Verification of the conformance of storage peripherals to the SCSI standard

is difficult because of the wide range of functionality, features, and options

included in the standard. This research

will result in a procedure for testing and

verifying the conformance of storage

peripherals to the standard, which can

be published and used by others to test storage peripherals.

Contact: William E. Burr, A216 Technology Bldg., 301/975-2914.

The Bureau is designing tools for editing,

compiling, and interpreting computer

communications protocol specifications.

The goal of this research is to advance

the state of the art in the application of tools to automatically realize executable

implementation of computer communications protocols which are based upon

and comply with formal specifications of protocols. As part of this project, Bureau

researchers are developing a syntax- directed editor for Estelle and, using the same grammar, devising a portable

compiler for Estelle and the supporting

runtime libraries.

Contact: John F. Heafner, B217 Tech- nology Bldg., 301/975-3618.

To enable computer vendors and users

to test their computer systems to make

sure they conform to networking stan- dards, NBS has established a laboratory

for conducting local area network

research and development activities. In this specially designed laboratory, researchers are studying conformance

testing, performance measurement,

analytic and simulation modeling, integration testing and network management,

and control of local area networks. Local area networking technology is necessary

Automated

Protocol Methods

Local Area

Networking

32
Computer Sciences and Technology

Electronics and

Electrical Engineering

for data communication in offices, factories, and laboratory environments where

distributed computer network applications are needed. While the interoperability

requirements of such networks can lead

to unique and expensive communication

solutions, the use of standards to achieve

product compatibility permits selection of

"off-the-shelf" equipment based on

cost/performance considerations.

Contact: John F. Heafner, B217 Technology Bldg., 301/975-3618.

Network Security

Architecture

To protect computer systems and

networks, NBS is developing a comprehensive security architecture consistent

with the Open Systems Interconnection

(OSI) Reference Model. Cryptographic

functions are being implemented in certain OSI layers to provide data

secrecy, data integrity, and peer entity authentication. The research will combine

the security standards for individual OSI

layers into a unified security framework.

As part of this project, Bureau

researchers will define a common inter- face for cryptographic algorithms and

develop a key management methodology

capable of providing keys to the cryptographic functions of any layer.

Contact: Miles E. Smid, A216 Technology Bldg., 301/975-2938.

As part of an NBS program aimed at meeting the metrological needs involved

in improving signal acquisition and

processing systems, Bureau researchers

are developing theory, methods, and

standards for waveform metrology of conducted signals. In one area, they are conducting the theoretical and

experimental research necessary to develop standards for determining the performance of waveform recorders operating nominally below 10 MHz. Techniques for synthesis of precision

waveforms and for characterization of those waveforms will be developed.

Theoretical studies will be conducted on

Fourier analysis, deconvolution tech- niques, and time-domain analysis.

Experimental work is planned in precision

pulse generation, static and dynamic

testing, and. assembly and interpretive

level programming for hardware control.

Contact: Barry A. Bell, B162 Metrology

Bldg., 301/975-2402.

Research in the Bureau's antenna

metrology program results in reliable techniques and standards for measuring

key performance parameters of antennas and components used with satellites, Earth terminals, radars, and communications systems. Scientists are now using

near-field scanning to characterize micro- wave and millimeter-wave antennas. The

principal emphasis of this work is on

developing spherical scanning to accom- modate the largest antennas and

adapting near-field scanning to anechoic

chamber environments, to permit greatly

increased use of near-field scanning in industry.

Contact: Allen C. Newell, Div. 723.05,

NBS, Boulder, CO 80303, 303/497-3743.

Waveform

Recorder

Standards

Mathematicians Elaine Barker and Miles Smid (seated) with

computer scientist David Balenson discuss cryptographic

techniques for securing network communications.

Research to improve the metrology used

to characterize compound semiconductors, especially gallium arsenide, is under way at NBS. Scientists are studying the electrical, optical, and physical properties of gallium arsenide to better understand and characterize

presently available device material. They

are using a number of measurement

techniques in this work, including optical

Antenna

Measurements

Gallium Arsenide

Studies

33
Electronics and Electrical Engineering

absorption, photoluminescence, infrared and Raman spectroscopy, Hall effect and

resistivity measurements, capacitancevoltage profiling, deep-level transient spectroscopy, photoconductivity and

photocapacitance, infrared imaging, and

x-ray topography and rocking curve analysis.

Contact: Michael I. Bell, 301/975-2081 or Richard A. Forman, 301/975-2047, A305

Technology Bldg.

Integrated Circuit Process

Metrology

Silicon

Characterization

Theoretical and experimental research on

semiconductor materials and process

physics at the Bureau is focused on

improving understanding of integrated

circuit fabrication technology and

increasing capability to measure and

characterize fabrication materials and

processes. Utilizing processing equip- ment and techniques appropriate to VLSI

chip fabrication, NBS scientists conduct

experimental studies on issues related to

state-of-the-art semiconductor processing

in a well-equipped clean-room semiconductor processing laboratory. For example, researchers are studying ion- implantation damage, oxidation growth

and interface trap formation, materials

effects caused by ion etching, thin-film properties, and plasma and ion-beam

chemistry. Other areas of interest include submicron (submicrometer) photolithography, reactive ion etching, beam

processing, and chemical and physical vapor deposition.

Contact: Stanley Ruthberg, 301/975-

2082 or Gary P. Carver, 301/975-2091,

A331 Technology Bldg.

NBS conducts research in semiconductor

materials, devices, and integrated circuits to provide the necessary basis for understanding measurement-related require- ments in semiconductor technology. As

part of this program, NBS scientists are employing electrical, optical, and x-ray methods to study the resistivity, dopant

distribution, and concentration of electri- cally inactive impurities, such as carbon

and oxygen, in silicon. They are developing new or improved techniques

for two- and three-dimensional mapping

of these properties, refining the quantitative aspects of existing methods, and

J \

-»—i*—rr

Electrical engineer Robert Gallawa measures the bandwidth of multi-mode optical fibers as part of an NBS program to develop measurement methods that can be used in fiber development, fiber evaluation in the marketplace, and fiber compatibility in communications systems.

developing methods that are nondestructive. Measurements performed for this research include four-probe, spreading

resistance, and capacitance-voltage

profiling; Fourier transform infrared spectroscopy; deep-level transient spectroscopy; and x-ray topography.

Contact: Michael I. Bell, 301/975-2081 or Jeremiah R. Lowney, 301/975-2048, A305

Technology Bldg.

NBS scientists are developing a basic understanding of magnetic properties of materials and structures to provide a sound basis for measurement techniques.

Specifically, researchers are studying

precision cryogenic vibrating sample

magnetometers, systems based on

superconducting quantum interference devices (SQUID'S), and laser-based magneto-optical systems. The primary

emphasis of this new program is in the

Magnetics

34
Electronics and Electrical Engineering

field of computer-related magnetics, but work is also under way on the basic physics of magnetic materials, such as

spin glasses, and on the measurement of very low-level magnetic effects. In a

related program in eddy current nondestructive evaluation (NDE), NBS

researchers are developing methods for mapping the very small ac magnetic

fields associated with eddy current test probes.

Contact: Frederick R. Fickett, 303/497-

3785 or Ronald B. Goldfarb, 303/497-

3650, Div. 724.05, NBS, Boulder, CO

80303.

Cryoelectronics Advances in digital electronics for telecommunications, radar, weapons

testing, fusion research, and data

processing will demand higher measure- ment speed than is now possible. The

Bureau is now conducting research aimed at exploiting superconducting

systems for measurements of extraordinarily high speed, accuracy, and sensitivity. For example, researchers are studying a series array Josephson

voltage standard, which is an exciting new approach to simpler, more accurate, and less expensive voltage calibrations and ultra-high-speed analog-to-digital converters and counters, employing as

active elements, superconducting

quantum interference devices (SQUID's).

Their goal is to develop the theoretical and experimental basis for new designs

and to fabricate and test these remarkable devices.

Contact: Richard E. Harris, Div. 724.03,

NBS, Boulder, CO 80303, 303/497-3776.

Semiconductor To develop physically sound techniques

Devices for characterizing, analyzing, and

predicting the operation and performance

of semiconductor devices, NBS is designing and improving measurement

methods for determining critical device

parameters for both VLSI-scale and

power devices. Research in device

modeling includes two-dimensional silicon MOSFET and GaAs MESFET model

development and investigations into the

validity of the physical assumptions typi- cally employed in silicon bipolar and

GaAs device models. Theoretical research is carried out on the transport of

ions and electrons in semiconductors for improved process modeling while experimental research on the nature and

characterization of electronic states in oxides and at oxide/semiconductor inter- faces is under way. Bureau scientists are developing methods for physical and

electrical measurements of device and

material parameters which are critical for verifying the accuracy and validity of device models. In addition, they are researching the electrical and thermal

properties of power semiconductor

devices.

Contact: David L. Blackburn, B310

Technology Bldg., 301/975-2053.

Integrated circuit test structures devel- oped by NBS are widely used by the semiconductor industry and other government agencies. These specially

designed semiconductor devices can be

used to characterize integrated circuit fabrication processes, to evaluate the

effectiveness of semiconductor

processing equipment, to obtain crucial parameters for device and process

models, and for product acceptance.

NBS work involves test structure design,

mathematical modeling, fabrication, data

acquisition, and data analysis. Bureau

scientists are conducting research on test structures for random fault detection,

yield analysis, and dynamic circuit characterization.

Contact: Loren W. Lmholm, B360 Technol- ogy Bldg., 301/975-2052.

As part of an NBS program to develop

theory, methods, and physical standards

for the measurement of electrical quantities in advanced high-voltage/high-power

systems, Bureau researchers are developing electro-optical methods for measuring electrical quantities and

phenomena. Finite-element code for electric field computation and computer-aided

data acquisition and analysis are the focus of theoretical studies. High-voltage

ac, dc, and impulse measurements; highspeed cameras; optical multichannel

analyzers; and lasers and detectors are addressed in the experimental work.

Contact: Robert E. Hebner, B344

Metrology Bldg., 301/975-2403.

Integrated Circuit Test Structures

Electro-Optical

Metrology

35
Electronics and Electrical Engineering

AC Voltage NBS is conducting both theoretical and

Standards experimental research on the synthesis of precision ac waveforms for use in ac

voltage standards operating nominally

below 10 MHz. The theoretical work

includes Walsh functions and Fourier

analysis, time-domain analysis, and preci- sion RMS-to-dc conversion techniques.

Experimental work involves high-speed,

high-accuracy digital-to-analog conversion; precision, high-speed switching;

assembly and interpretive level program- ming for hardware control; and wide- band, fast-settling amplifiers.

Contact: Barry A. Bell, B162 Metrology

Bldg., 301/975-2402.

Testing New strategies are needed for evaluating

Electronic the performance of complex electronic Systems circuits with the fewest possible tests. NBS is planning a new program which

will include theoretical studies of modeling for nonlinear systems, optimization techniques using matrices, statistical and random processes, and artificial intel- ligence. In addition, experimental work

would address test strategies for component and instrument testing; fault diagnosis, function testing, and calibration; and computer analysis using both desktop and supercomputers.

Contact: Barry A. Bell, Bldg., 301/975-2402.

B162 Metrology

tory is equipped with a Raman micro- scope for examining regions several micrometers in size, automated digital data acquisition and processing, variable wavelength lasers, and multiple-grating

monochromators.

Contact: Michael I. Bell, A305 Technology

Bldg., 301/975-2081.

NBS scientists are developing measure- ment methods for characterizing gaseous

dielectrics for high-voltage power

systems. In this study, the theoretical work is expected to address Boltzmann

equilibrium statistics, chemical kinetics code, and computer-aided data acquisition and analysis. Experimental work will focus on high-voltage ac and dc tests, gas chromatograph and mass spectrometer techniques for chemical characterization, and partial discharge measurements. Much of the Bureau's work in advanced power metrology is performed in newly completed highvoltage and high-current laboratories. These facilities can generate voltage

pulses with peak amplitudes up to 600,000 volts and current pulses with peak amplitudes up to 100,000 amperes.

Contact: Robert E. Hebner, B344

Metrology Bldg., 301/975-2403.

Gaseous

Dielectrics

Raman Scattering Some of the world's most advanced

measurement techniques for the rapid

advancement of electrical and electronic technology are available at NBS. For example, a Raman spectroscopy facility

is used for light scattering studies of

liquids, solids, and gases. Specific research being done at the facility includes chemical and structural analysis

of thin films and ion-implanted layers, investigations of impurities and other defects in semiconductors, studies of the

structural and electrical properties of semiconductor superlattices and quantum

wells, and development of new quantitative spectroscopic methods.

In this laboratory, equipment is avail- able for studies of the pressure and

temperature dependence of Raman

spectra in the range of 4 to 600 K and

up to approximately 100 kbar using a diamond-anvil pressure cell. The laboraPhysicist Gary Carver prepares to inspect a silicon wafer under

a microscope in the Bureau's semiconductor processing

laboratory.

36
Fire Research

Flammability and

Toxicity

Measurement

Bureau researchers are creating ways to measure and characterize the combustibility of furnishings and building materials and the extent combustion products

affect living organisms. Typically NBS

research focuses on assessing the appropriate applications of the NBS

toxicity screening test, evaluating the extent to which a limited number of gases determine the lethality of combustion products, and developing a methodology for predicting soot and gas

production in full-scale fires from benchscale methods. In addition, Bureau

researchers are generating a detailed model for the burning of upholstered

furniture, devising a measurement meth- odology to predict the propensity of cigarettes to ignite soft furnishings, and

aiding the use of the cone calorimeter in engineering and code applications.

Contact: Vytenis Babrauskas, A363

Polymer Bldg., 301/975-6679.

Fire Simulation Over the past decade, NBS researchers have developed many computer models

of various aspects of fire. Research in this project is aimed at providing the expedient transfer of scientifically based

technology from NBS to the professional user community and creates a link between the computer-based activity of the Bureau and others doing similar or complementary work. Researchers

develop engineering systems for design

application as well as expert systems,

collect supporting data and programs, and operate a working and training

laboratory dedicated to computer

modeling and other fire safety computations.

Contact: Harold E. Nelson, A247 Polymer

Bldg., 301/975-6869.

Hazard Analysis The United States has one of the worst

fire records in the industrialized world. The Bureau is providing the scientific and

engineering bases needed by manufacturers and the fire protection community

to reduce both these losses and the cost

of fire protection. One project involves the development of predictive, analytical

methods which permit the quantitative assessment of hazard and risk from fires. The Bureau bases these methods on

numerical modeling, but also includes

hand calculation methods for estimating

hazards and production of design

curves/tables to be used by architects and engineers. To ensure widespread

use, the necessary data must be readily

available, and data input and presentation must be in terms readily understandable by the average professional. Thus,

the projects include a strong emphasis

on state-of-the-art computer graphics and

computer-aided design techniques.

Contact: Richard W. Bukowski, B356

Polymer Bldg., 301/975-6879.

Predicting fire growth requires a

fundamental understanding of elemental

fire processes. Therefore, the Bureau is attempting to develop predictive methods

to describe the processes of fire growth

and elemental processes of fire growth

and extinction as related to gaseous,

liquid, and solid fuel combustion and the performance of fire safety systems.

Researchers are probing fire growth

within a single compartment, the spread

of fire to adjoining spaces in multi- compartment structures, and the action

of fire suppressants. In addition, they are examining the overall dynamics of the fire scenario and related elemental processes such as ignition, flame spread, pyrolysis,

extinction, and fire-related transport processes. For these studies, they utilize mathematical techniques, experimental

studies, correlations, and similitude methods to develop predictions.

Contact: James G. Quintiere, B250

Polymer Bldg., 301/975-6863.

NBS is conducting research to develop a science base for the gasification and

combustion of natural and synthetic

polymers, particularly for the more

applied fire research activities. For example, NBS scientists are working on

the kinetics and heats of combustion for wood, theoretical modeling of thermal degradation of polymers, smoldering

research, and detailed degradation

mechanisms of polymers.

Contact: Takashi Kashiwagi, B258

Polymer Bldg., 301/975-6693.

Fire Growth and

Extinction

Polymer

Combustion

Research

37
Fracture and Deformation

—-——-— .

Welding The integrity of welded joints is a primary

Research concern in the design and fabrication of engineering structures. Therefore, NBS is directing research toward improving the

fracture resistance of weldments and

assessing weld quality by nondestructive

evaluation (NDE) techniques. Specific

goals of the research are to improve the

fracture toughness in the heat-affected zone of steel weldments and in the weld

metal of materials for low-temperature

service and to better weld soundness

through increased understanding of the metal transfer process in arc welding. In addition, Bureau researchers will develop

electromagnetic acoustic transducers (EMATs) for ultrasonic inspection of weld- ments. The research is conducted in the Bureau's welding and NDE laboratories which house equipment for shielded metal arc, gas metal arc, and gas tungsten arc welding; radiographic, ultrasonic, eddy-current, and penetrant techniques

for NDE of weldments; acoustoelastic techniques for residual stress measurements; and a precision power supply,

high-speed photography, and laser shadow techniques for metal transfer

studies. Recently, NBS scientists devel- oped techniques for porosity reduction in aluminum weldments, spatter reduction in gas metal arc welding of steels, flaw size measurements in steel welds using ultra- sonics, and residual stress measurements

in aluminum weldments.

To ensure the safety and reliability of Fracture

engineering structures, the Bureau is Mechanics

working to establish a sound technical basis for codes and standards for struc- tures. Specifically, researchers plan to develop a rational basis for material toughness requirements, allowable stress

levels, minimum service temperatures,

and weld quality standards. NBS capabilities include test equipment with load

capacities up to 6,000,000 pound-force,

numerical analysis of cracked structures, experimental mechanics, and fracto- graphic techniques. Bureau scientists evaluate materials performance at cryo- genic and elevated temperatures, under

static and dynamic loading, in corrosive and hydrogen-charging environments,

and with random amplitude loading. They

have recently completed a fitness-for- service evaluation of steam boilers, a

failure analysis of a refinery pressure

vessel, dynamic crack arrest tests on

structural steels, and a new test method

for measuring the fracture toughness of weldments.

Contact: Harry I. McHenry, Div. 430,

NBS, Boulder, CO 80303, 303/497-3268.

Contact: Thomas A. Siewert, 303/497-

3523 or A. Van Clark, 303/497-3159, Div. 430, NBS, Boulder, CO 80303.

'18
Manufacturing Engineering

Automated

Manufacturing

Systems

Hardware

Precision

Engineering

Automated manufacturing systems

include flexible manufacturing systems

and machine tools into which intelligent sensors and controls of the production

processes, including the machining itself, have been embedded. To support such

developments by industry, NBS conducts

several research programs. In manufacturing systems, scientists are investigating

generic control systems, full-task programming, data organization, sensor

organization, system initialization, and the object-data analogy. In the area of small displacement measurement, researchers

are developing transducers with 100-kHz

bandwidths for measuring fractional micro-inch displacements over wide

temperature ranges for the next generation coordinate measuring machine.

Their efforts in real-time error correction

of machine tools are centered on

extending microprocessor-based tech- niques for real-time correction of the kinematic (as well as static) machine

errors and tool wear. They are studying

transient waves in solids by investigating the origin, propagation, measurement,

and direct-and inverse-prediction of micro-mechanical waves in acoustic emission and ultrasonics. Furthermore, Bureau researchers are focusing their studies of transducer fields on the fields produced in solids by electromechanical transducers by modeling and measuring

of the fields point-by-point within the

solids.

Contact: Donald S. Blomquist, B108

Sound Bldg., 301/975-6600.

The precision-engineering industries create and use precision mechanical

machines for production applications,

such as high-tolerance diamond-turned

optical disks as information storage

media. NBS conducts research in the design and high-accuracy performance

of several types of next-generation

machines. Bureau scientists are focusing

their studies of thermal modeling of machine tools and coordinate measuring

machines (CMM's) on thermal distortions

of the geometry of machine tool/CMM's

using experimentally-verified finite-element

analysis. In robot metrology, researchers

are investigating techniques for measuring robot end-effector positioning,

including a spherical-system generalization of the extensible ball-bar and a six- transducer laser-tracking approach. In the area of absolute air refractivity, researchers are developing a prototype

refractometer based on a heterodyne

tracking relative to a stabilized two- frequency laser. Research on advanced

coordinate measuring machines is aimed

at devising a sub-0.1 nanometer

accuracy coordinate measuring machine

based on precision mechanical design,

high-resolution interferometry, and elec- tron probe techniques.

Contact: Robert J. Hocken, A109 Metrol- ogy Bldg., 301/975-3464.

For those industries which create and

use computer-controlled manufacturing

systems, software systems are the critical element. NBS provides research for soft- ware in automated manufacturing

systems in several areas. In automated

process planning, researchers are investigating data structures for automated

process planning, distributed system

architectures, machinable-feature identifi- cation, and expert systems/machinelearning for manufacturing systems.

Researchers are also studying architectures, algorithms, and techniques for real- time adaptive control, scheduling, and

optimization of cell- and workstation-level operations for FMS cell and workstation

control systems. In addition, for manufacturing systems architectures, they are

devising functional models of manufacturing organizations to standard system

architectures.

Contact: Howard M. Bloom, A127 Metrol- ogy Bldg., 301/975-3509.

Automated

Manufacturing

Systems

Software

39
Manufacturing Engineering Metallurgy

Robotics The industries which create and apply

robotics systems, i.e., intelligent machines

which can autonomously operate on the

physical environment, range from the makers of industrial robots to the producers of machine vision and other advanced sensory systems. NBS is conducting research on the design of genencally applicable control systems for such devices. One project involves image

processing architectures. Here, researchers are investigating methods for machine-processing of complex sensory

input data employing low-level image

processing systems such as PIPE inter- faced to high-level symbol-manipulating

computer algorithms. Another study concerns world modeling, in which

research focuses on methods of constructing computationally efficient world-model representations of three- dimensional object descriptions and

geometry of visual images to support, for example, spatial reasoning and predictions of dynamic properties of objects.

In addition, Bureau scientists are studying artificial intelligence for robots by developing techniques to bridge the gap between high-level intelligent planning, decision-making, optimization and

goal selection, and low-level servo

control. In the area of off-line programming, they are studying group tech- nology, interactive graphics, and

object-oriented programming as tech- niques to overcome the limitations of

explicit programming required for robot

control.

Contact: James S. Albus, B124 Metrol- ogy Bldg., 301/975-3418.

In many industrial operations, the wear of Wear of Metals

machine components and materials is one of the principal processes that limits the service life of equipment. At NBS an

extensive research program on the

effects of wear and erosion on materials

is under way to investigate many of these

industrial problems. NBS scientists are studying a wide variety of wear modes,

including adhesive wear, abrasive wear,

erosion, galling wear, and lubricated wear. One area of emphasis concerns

the effects of materials parameters such

as toughness, hardness, ductility, work- hardening characteristics, alloy composition, and microstructure. As part of this program, NBS scientists are also working with industrial researchers to study the galling wear of alloys useo in valves and sliding seals. In this research, scientists are using such

characterization techniques as scanning

and transmission electron microscopy

and various surface analytical methods.

Research has shown that high-resolution

microscopy can frequently be used to

identify the causes of wear, for example,

through examination of wear debris

particles. NBS has many instruments for conducting wear and erosion experi- ments under controlled conditions and

researchers incorporate standard test methods and equipment where

appropriate.

Contact: A. William Ruff, B106 Materials

Bldg., 301/975-6010.

The use of artificial joints and fracture

fixation devices has increased at a rapid

rate in recent years. This is due largely to the impressive success of early designs

such as the artificial hip joint that used

available stainless steel and polyethylene

materials. However, as newer types of implants are used for longer times in patients, it has become clear that improved materials are needed for stronger, lighter, more compatible

implants. Bureau scientists are studying

the mechanical properties and environ- mental reactions of metals with strong

potential for use as implants. They are

placing particular emphasis on fatigue

Synthetic Implant

Metals

40
Metallurgy

Micromechanical

Properties of Materials

life, wear, fretting, processing methods,

and surface reactions that occur when

the materials are placed in the body. In addition, NBS is characterizing the

biocompatibility of these materials by

observing cellular growth on metallic surfaces and by studying metal/organic

reactions. For this project, NBS

researchers are working with several manufacturers in the artificial implant

industry to examine the properties and

performance of relevant materials. The

equipment available for this research

includes mechanical testing machines,

friction and wear testers, scanning and

transmission electron microscopes, and

electrochemical apparatus.

Contact: Anna C. Fraker, B128 Materials

Bldg., 301/975-6009.

The success of many technically

advanced materials, such as composite

materials, electromagnetic recording

tapes and disks, and integrated circuits, depends on their mechanical perfor- mance. These materials have refined,

complex, and heterogeneous microstructures, but problems arise when they

behave as systems and reflect the overall mechanical contributions of components

a micrometer or less in size. Generally,

hardness numbers from the indentation resistances of pointed tools are used to determine mechanical performance.

However, NBS researchers are developing a new and significantly better solution, which is derived from the hardness

testing practice. We have expanded this technique with the NBS dynamic microin- dentation instrument, an apparatus that can be used to determine mechanical

performance within sample volumes of less than a micrometer on a side. Three important innovations have

resulted from this project. Two have been

completed: indentations can now be

described by continuous measurements

of applied loadings and penetration

depths, and indentations can be made

using loading times ranging from hours

down to milliseconds. The Bureau's goal,

at present, is to obtain conventional

uniaxial tensile properties (Young's

Modulus, yield stress, and strain) rather

than to use hardness numbers. From an

industrial viewpoint, the technique aids development of new materials, studies of thermal and mechanical processing

effects, and nondestructive examinations

of fracture resistance.

Contact: Robert S. Polvani, B1 12

Materials Bldg., 301/975-6003.

Corrosion is a major limiting factor in the service life and cost of many products,

plants, and equipment. The costs of metallic corrosion to the U.S. economy

are estimated to be $167 billion in 1985

dollars, $25 billion of which could be

saved by using existing technology. The

National Association of Corrosion

Engineers (NACE) and NBS have joined

together in a collaborative NACE/NBS

Corrosion Data Program to reduce these enormous costs of corrosion. The central focus of the Corrosion Data Program is to establish an evaluated corrosion data- base that researchers can access easily

by computer to obtain data in a number

of possible graphical or tabular formats. The researchers are developing evaluation methodologies and a prototype data- base for areas covering thermodynamic

and kinetic corrosion data. NBS scientists are emphasizing interactions with industry both to help set priorities for data

projects and as a source of corrosion data for the database.

Contact: Gilbert M. Ugiansky, B254

Materials Bldg., 301/975-6022.

Corrosion has been recognized as one of the major causes of degradation of all kinds of metallic structures, with financial costs well in the billion-dollar range. Since corrosion reactions are of elec- trochemical nature, electrochemical measurements can give important infor- mation about the chemical processes

causing the corrosion and the rate of corrosion as well as its forms, whether

uniform or localized corrosion. These

measurements involve the determination

Corrosion Data Program

Corrosion

Measurements

41
Metallurgy

Process Control

Sensors

of current and potential and their varia- tions with time; the frequency spectrum

of the ac impedance of corroding elec- trodes; and the detection and analysis of the random fluctuations of electrical parameters.

Electrochemical methods for measuring

corrosion rates offer the possibility of following the course of the process in a

nondestructive way and assessing the

effect of various environmental variables. Other electrochemical techniques can

shed light on the kinetics of the corrosion

reactions and on the critical factors which

may contribute either to catastrophic

failures or corrosion prevention. For example, Bureau researchers are now

using these methods to investigate the electrochemical processes associated

with stress corrosion cracking of brass and copper in ammonia solutions and to examine film breakdown and pit initiation on passive metals.

Contact: Ugo Bertocci, B254 Materials

Bldg., 301/975-6017.

NBS researchers are using special facili- ties to develop advanced measurement

methods and standards in support of emerging process control sensors and

their application to intelligent processing

of materials. Measurement methods avail- able include ultrasound, eddy currents, and acoustic emission. In particular, noncontact ultrasonic facilities have been

designed featuring high-intensity pulsed

lasers, electromagnetic acoustic trans- ducers, and laser interferometers. Coupled with state-of-the-art materials- processing equipment and expertise, these facilities offer a unique opportunity

to ascertain feasibility and develop proto- type specifications for a wide spectrum of sensor needs including the measurement

of internal temperature, phase transfor- mations, surface-modified layers, porosity,

grain size, and inclusion/segregate distri- butions.

Contact: Haydn N.G. Wadley, A167

Materials Bldg., 301/975-6140.

The rapid solidification of alloys can Rapid

produce new types of materials unob- Solidification tamable by conventional means. Because

of their special properties, rapidly solidi- fied alloys are being widely investigated

and are beginning to be introduced into commercial devices. Equipment is avail- able at the Bureau to study alloys

produced by each of the three major

kinds of rapid solidification techniques:

atomization techniques in which fine

liquid droplets are formed and rapidly frozen to produce alloy powder; ribbon techniques in which a very thin liquid stream or ribbon is rapidly solidified; and

rapid surface-melting and refreezing tech- niques in which a directed energy

source, such as an electron beam, is scanned across a surface. The emphasis

in the NBS work is on measurement and

predictive modeling of the rapid solidifica- tion processes. Researchers are studying

crystalline, metallic glass, and the new

quasicrystal alloys recently discovered at NBS. Efforts are under way to apply

advanced sensors to an inert gas atomization system to allow feedback and

control of this process. Because

processing conditions influence alloy homogeneity, microstructure, extended

solid solubility, and the production of new

alloy phases, control of these features is critical for producing special properties in these new materials.

Contact: John R. Manning, A153

Materials Bldg., 301/975-6157.

The corrosion of metals in natural and Field Corrosion

man-made environments is very costly to of Metals

industry and government. For several

years, Bureau researchers have been

involved in developing methods for measuring the corrosion of metals in field conditions such as steel piling in soil and

seawater, electric utility lines in soil, and

most recently, steel in concrete. To measure the corrosion of reinforcing steel

in concrete bridge decks, NBS scientists have developed a small, portable

computer system. With this system, scientists apply electrochemical techniques

normally limited to the laboratory to measure the corrosion. This new

approach, which allows faster, more

accurate corrosion measurements, can be used to evaluate the effectiveness of protection systems in place. The system

42
Metallurgy

Neutron Scattering

and Diffraction

Steel Slag

Thermochemistry

has been applied to several bridges in Maryland and will soon be used on

bridges in Virginia.

Contact: Edward Escalante, B254

Materials Bldg., 301/975-6014.

The U.S. steel industry needs ther- mochemical databases and models for the design ot new or improved steel- making processes. To design such

processes, NBS initiated programs in three areas. Bureau researchers are measuring refractory and slag ther- mochemical equilibria, evaluating the

scattered literature data, and developing

computer models relating experimental data to industrial conditions. NBS has

unique experimental facilities for measuring key phase equilibria and kinetics.

Contact: John W. Hastie, A329 Materials

Bldg., 301/975-5754.

Discussing quasicrystal structures in alloys are (I. to r.) Dan

Shechtman, Israel Institute of Technology; Frank Biancaniello,

NBS; Denis Gratias, National Science Research Center, France; John Cahn, NBS; Leonid Bendersky, Johns Hopkins University;

and Robert Schaefer, NBS. The discovery at NBS of quasicrystal structures in materials challenges a 100-year-old theory

of crystallography, and the existence of quasicrystals may

make it possible to produce materials with radically different properties.

Precise information on the crystal struc- ture (arrangement of atoms and

molecules) in solids is often a key to understanding or improving the properties of modern materials or creating new

ones. Many important materials, e.g., ceramics, catalysts, and rapidly solidified alloys, often can be obtained only in powdered form. State-of-the-art capabilities are in place at the Bureau for measuring and analyzing the magnetic struc- ture of polycrystalline materials by

neutron diffraction. The facilities available

for diffraction experiments for both powders and crystals include a four-circle diffractometer and a multidetector,

high-resolution powder diffractometer, as

well as instruments which allow measure- ments in a single-crystal or energydispersive mode.

NBS researchers continue to develop

improved methods for accurate structure refinement and for measurement of internal stresses in materials. Currently, a number of industrial scientists are

collaborating with NBS staff in neutron

diffraction studies of inorganic catalysts, new kinds of ionic conductors for small

batteries and fuel cells, improved

ceramics for microcircuit substrates and

engine components, and highperformance lightweight alloys for advanced aircraft. NBS scientists are also working to determine how residual stress and texture in bulk metals and ceramics

affect their application in high-technology

products.

Contact: Edward Prince, 301/975-6230

or Antonio Santoro, 301/975-6232, A106

Reactor Bldg.

The vibrational dynamics and diffusion of hydrogen in metals and molecular species in heterogeneous catalysts are studied at the Bureau with inelastic and

quasielastic neutron scattering and

neutron diffraction. The results of this research reveal the bonding states and

atomic scale interactions and diffusion paths in such materials. Recent progress has allowed in-situ spectroscopic studies

of hydrogen and molecular species down

to 0.1 of an atomic percent. These measurements can provide direct information,

for example, on the molecular processes

that affect reaction and selective release

of chemicals in industrial catalysts and on

the local trapping and clustering of hydrogen in metals and semiconductors,

Neutron

Diffraction

Neutron

Spectroscopy

43
Neutron Scattering and Diffraction Nondestructive

Evaluation

which cause embnttlement of corrosion

or changes electronic properties. NBS

scientists are working with researchers from several industrial laboratories to study zeolite catalysts. For this research, the equipment available includes three- axis neutron crystal spectrometers and

time-of-flight spectrometers for inelastic scattering along with neutron diffractometers, which measure structural and

dynamic processes in the time regime

from 1Cr10 to 10"14s. Controlled temperature devices are available from 0.3 to 1300 K.

Contact: John M. Rowe, 301/975-6229

or John J. Rush, 301/975-6231, A106

Reactor Bldg.

Small-Angle Small-angle neutron scattering (SANS) is Neutron used to characterize submicron structural Scattering and magnetic properties of materials in the size regime from 1 to 100 nm. The

SANS diffraction patterns produced by

structural features in this size regime — for example, by small precipitates or cavities

in metal alloys, by micropores or cracks

in ceramics, by colloidal suspensions and

microemulsions, or by polymers and

biological macromolecules-can be

analyzed to give information on the size and shape of the scattering centers as

well as their size distribution, surface

area, and number density. This detailed microstructure information is often a key

to the prediction or understanding of the performance or failure, modes of structural materials and materials processing

conditions. A number of scientists from the chemical, communications, advanced

materials, and aerospace industries are already engaged in SANS research at NBS. Their measurements are carried out

with long wavelength neutrons on the 8- m-long NBS SANS spectrometer which

utilizes a 65 by 65 cm position-sensitive detector to record data over the entire small-angle region simultaneously.

Computer-automated apparatus is avail- able for maintaining samples at temperatures from 4 to 700 K and in magnetic

fields up to 20 kilogauss. To extract

structural information from the data, the researchers analyze SANS patterns with an interactive color graphics system and

related programs.

Contact: Charles J. Glinka, 301/975-

6242 or James A. Gotaas, 301/975-6243,

A 106 Reactor Bldg.

Rapidly solidified metal powders provide a basis for alloys which exhibit, after consolidation, high strength-to-weight

ratios, improved fracture toughness and

fatigue resistance, unique magnetic

properties, and high corrosion resistance. Because neither real-time automated

process control techniques for producing

rapidly solidified metal powders nor tech- niques for real-time process control of materials exist, NBS recently initiated a model research project which brings

together special capabilities that already

exist at NBS. Using a pilot facility for studying the automated production of rapidly solidified metal powders, NBS

researchers will develop process models,

sensors, and adaptive control techniques

for producing rapidly solidified metal powders. Two general categories of sensors are involved: one which measures processing parameters, such

as temperatures, pressures, and flow

rates; and the other includes nondestructive evaluation sensors which measure or monitor non-intrusively important properties or characteristics of the molten,

solidifying, or solid metal powders while they are being produced. Bureau scientists are designing a new,

inert gas atomization system, and they are conducting basic research in solidifi- cation science to relate the microstructures formed during solidification to the processing conditions and to the subse- quent properties. Research at the completed facility is aimed at combining

the process models and the real-time sensors with expert computer systems for adaptive control.

Contact: H. Thomas Yolken, B344

Materials Bldg., 301/975-5727.

The eddy-current method of nondestructive evaluation (NDE) is capable of detecting extremely minute cracks, pits, and other discontinuities in surfaces and

near-surface regions of metals, alloys, and other electrically conductive

materials. In addition, it can be used to characterize near-surface properties of thin coatings, films, and bulk materials However, to characterize such flaws or properties reliably and reproducibly,

eddy-current NDE must be made into a

quantitative measurement system Therefore, the goal of an on-going NBS project

Nondestructive

Evaluation for Metal Powder

Production

Eddy-Current

Nondestructive

Evaluation

44
Nondestructive Evaluation Polymers

is to develop measurement methods, cali- bration procedures, and standards

needed for quantitative eddy-current

testing. Experimental investigations in several NBS groups are linked with theoretical studies at Stanford University and

other related NBS research. Studies on eddy-current calibration standards, based on electrical-discharge

machined notches, have shown that such

artifacts must be used with caution. Therefore, comparisons of theory and

experiment were recently extended to low-conductivity materials and to real fatigue cracks in order to simulate real test situations more accurately. Results show that magnetic field mapping of eddy-current probes enhances capabilities for characterizing flaws via eddycurrent measurements. In addition, field mapping can detect differences in probes of apparently identical construction. Furthermore, field profiles of ferrite core probes, which are difficult to calculate, can now be measured directly. Bureau scientists have developed a new

calibration method for uniform field probes and demonstrated an eddycurrent technique for monitoring fatigue crack growth. Future studies will also address reflection probes.

Contact: H. Thomas Yolken, B344

Materials Bldg., 301/975-5727.

Using electrohydrodynamic atomization, metallurgist Stephen

Ridder produces rapidly solidified alloy powders.

Fiber-reinforced composites offer major

advantages, particularly versatility in processing combined with high strength

and stiffness at low weight. Continuation

of the current growth in the production of these materials, however, is hindered by

a need for more rapid and reliable processing. For this reason, the NBS

program is aimed at developing new

measurement tools to study the reactions associated with processing and the use

of these methods to understand the rela- tionships among processing parameters,

the microstructure of the fabricated

materials, and their performance properties. Such scientific understanding will facilitate both advances in processing

methods and implementation of on-line control and automation. The development

of this understanding requires researchers to monitor the materials during the curing process to observe

simultaneously chemistry, morphology

development, flow, molecular network

formation, build-up of residual stresses,

interfacial effects, and wetting and

spreading.

The NBS program currently has 10

different spectroscopic, dielectric, thermal, and mechanical techniques

available for cure monitoring and others under development. This diversity of tools provides a unique capability both for evaluating and calibrating new measure- ment methods and for analyzing model

thermoset systems. For example, through

cooperative projects with NBS, several

industries have selected and developed

monitoring methods for their particular

problems.

Contact: Donald L. Hunston, A207

Polymer Bldg., 301/975-6838.

Knowledge of the relationships between

mechanical properties of polymers and

polymer structure is important to the design and processing of materials for optimal performance. Therefore, the Bureau is studying semicrystalline

polymers, polymer glasses, elastomers, molecular composites, and fibers to develop improved models of mechanical

behavior, characterize structure from the atomic to fine texture level, and elucidate

relationships between mechanical perfor- mance and structure. A wide variety of techniques is used at the Bureau to characterize the structure

of polymers in the solid state. Nuclear

Composites

Processing

Polymer

Structure

45
Polymers

Dental and

Medical Materials

magnetic resonance spectroscopy is utilized to determine molecular orientation, molecular dynamics, and microstructure on the 1- to 10-nm scale. Microstructural information is deduced

from C-13 lineshapes obtained with magic angle spinning or by proton "spin

diffusion" experiments in which domainsize information is inferred from the rates

at which proton magnetization diffuses in the presence of magnetization gradients. Fourier transform infrared spectroscopy is applied to determinations of molecular

architecture, orientation, and molecular

processes, such as measurement of the amount of chain scission associated with mechanical deformation of polymers.

Optical and electron microscopic studies

of polymers elucidate microstructural

features, including spherulytic morphologies, lamellar texture, fiber structures, and crystallization habits. To examine the

relationships between mechanical perfor- mance of polymers and fine structures, NBS scientists are investigating the morphological changes that polymers

undergo when they are deformed. Wideand small-angle x-ray diffraction tech- niques, which include the use of position

sensitive detectors, are also employed in these investigations.

Contact: Bruno M. Fanconi, A305

Polymer Bldg., 301/975-6770.

Modern dental and medical materials

utilize numerous substances in an array

of combinations. NBS has a comprehensive program that is aimed at increasing basic understanding of the causes for failure or poor performance of these

materials, proposing and testing new

material systems, and transferring the

resultant science and technology to industry. The program has the active

participation of researchers from the American Dental Association, the National Institutes of Dental Research,

dental industries, and universities. Researchers are working in a number

of areas. For example, in a tribology

study, scientists are examining wear and

degradation of materials in various environments, and in a bioadhesion

project, they are making new monomers

for adhesion to tissues. In addition,

improved resins are being synthesized to produce polymers that have improved

properties such as wear resistance,

higher strength, resistance to oral fluids, or x-ray opacity.

In an effort to improve the strength of dental systems, different combinations of materials are being designed and tested. They include ceramic-metal, resin matrix composites, metal-cement, cement-tooth,

and composite-adhesive-tooth materials. To improve the systems, Weibull

statistical analysis is employed to identify the weakest links. Finite element analysis can be applied to define stress states

within systems.

In the area of precision metal casting processes, researchers are using strain gauges to monitor changes in dimensions of investment patterns at pattern

sites. A unique casting monitor has been

designed that could also be used for rapidly solidified alloys.

Contact: John A. Tesk, A143 Polymer

Bldg., 301/975-6801.

NBS is conducting a number of studies on the electrical properties of polymers.

The research is focused on dielectric measurements, fundamentals and appli- cations of piezoelectric and pyroelectric

polymers, measurement of space charge

distribution within polymer films, and ionic conduction in solid polymers. In the area

of dielectric measurements, Bureau scientists have developed instrumentation and

data analysis which can measure the

dielectric constant and loss of polymer

films over a frequency range of 10"3 to 10 5 Hz in less than 30 minutes. This makes it feasible to follow changes in the

dielectric spectrum as a function of time, processing conditions, or other parameters.

The toughness, flexibility, low dielectric constant, and an acoustic impedance

close to water make piezoelectric

polymers ideal for many transducer appli- cations. NBS staff have considerable

experience with the fundamental properties of polymers such as polyvinylidene

fluoride and its copolymers and can work

with industry to develop transducers for novel applications or assist in measuring

the properties of new piezoelectric

polymers or composites. Bureau scientists have designed

instrumentation and data analysis to measure the charge or polarization distri- bution across the thickness of polymer

Electrical Properties

At,
Polymers

film by analyzing the transient charge

response following a pulse of energy on one surface of the film. This technique

has been used to detect the presence of non-uniform electric fields in the poling of piezoelectric polymers and is currently

being used to investigate the role of space charge in the dielectric breakdown

of polymer insulation. Ionic conduction in polymers has

potential application in polymeric electrolytes for high-energy density batteries. The dissolution of salts in polymers and

their effect on ionic conduction as well as

other polymer properties are being

studied by a variety of techniques

including thermal analysis, x-ray diffraction, optical microscopy, and impedance

spectroscopy.

Contact: George T. Davis, B320

Polymer Bldg., 301/975-6725.

Molecular Thermosets are used extensively in Networks numerous practical applications, especially polymer-based composites.

However, knowledge of the basic structural entity of the thermosets, i.e., their molecular network structure, is very

limited. Therefore, Bureau researchers have developed a neutron scattering

technique that can be used to quantitatively determine such characteristics of the network as the average distance

between crosslinks, the rigidity of the network, the molecular weight distribution between crosslinks, and the topological

heterogeneity of the network structure. Current NBS research focuses on

developing correlations among chemical

compositions, processing conditions, and

resulting network structure for epoxy-type

polymers. To establish processingstructure-property relations, these

materials are then evaluated to determine

performance properties such as fracture behavior. The neutron scattering tech- nique is also being used to study how

the molecular network deforms when the

material is placed under load. These

studies can directly benefit industries by

providing guidelines for designing and

processing polymers for optimum perfor- mance.

Contact: Wen-li Wu, A209 Polymer

Bldg., 301/975-6839.

Takahiro Sato, a guest scientist from Osaka University, Japan, uses the temperature-jump light scattering technique to record the phase separation behavior in molecules.

Small-angle x-ray scattering (SAXS) can

be used to characterize structural elements of polymers, ceramics, and

metals in the 1- to 100-nm size range. The Bureau has successfully used this technique to study phase separation,

crystallite morphology, molecular dimensions, void formation, pore characteristics, and many others. A state-of-theart, 10-meter SAXS facility has been

constructed at NBS for such studies, and

it is available for cooperative research.

This SAXS facility uses a 12-kW rotating

anode source, pinhole collimation, and a

two-dimensional position-sensitive detector to provide high resolution and

simultaneous recording of all scattering data over the entire small-angle region. In addition, a computer-assisted interactive data reduction and analysis program is available with color graphics display for the two-dimensional image. Structural and dimensional information can be

extracted using various available model

analysis and curve-fitting procedures.

Contact: Charles C. Han, B208 Polymer

Bldg., 301/975-6772.

Small-Angle

X-Ray Scattering

47
Polymers Product Standards

Polymer Blends Blending polymers has become an effective method for producing highperformance engineering polymers. The

fundamental data required to design a manufacturing process include the

equilibrium phase diagram, the energetic

interaction parameter (compatibility)

between the blend components, diffusion

coefficients, and the interfacial tension. At NBS small-angle neutron scattering has

been used to measure the interaction parameter and phase diagram of polymer blends. NBS scientists have

developed forced Rayleigh scattering and

temperature-jump light scattering tech- niques to measure polymer-polymer diffu- sion and other parameters which control phase separation kinetics and

morphology.

Currently, Bureau researchers are

testing various kinetic theories of phase

separation and late-stage coarsening and

studying the control of morphology and

mechanical properties of microphaseseparated polymer blends. As part of this program, they are working with industry

to study the homogenization and phase

coarsening of rubber blends.

Contact: Charles C. Han, B208 Polymer

Bldg., 301/975-6772.

Fluorescence Bureau researchers are evaluating

Monitoring fluorescence spectroscopy, which is used

to characterize the structural and dynamical properties of polymer molecules. For example, fluorescence quenching is employed to monitor the uniformity of mixing in polymer blends and in particlefilled polymer melts. In addition, excimer

fluorescence is utilized to monitor the cure of thermosetting resins, while fluorescence anisotropy is used to monitor the non-Newtonian flow of polymer solutions and melts. At NBS, the measurements are carried out with a

spectrofluorimeter and a nanosecond

spectrofluorimeter. In combination with

optical fibers, which are used to get the

exciting light into the interior of a composite part, the fluorescence tech- niques are attractive for process

monitoring of composites.

To help fulfill the needs of laboratories. Laboratory

industry, governmental regulatory agen- Accreditation

cies, purchasing authorities, and Program

consumers for reliable laboratory testing.

NBS operates the National Voluntary

Laboratory Accreditation Program

(NVLAP). NVLAP is a voluntary system

for assessing and evaluating testing laboratories and accrediting those found

competent to perform specific test methods or types of tests on products

and materials. Through this program,

laboratories are accredited for testing a

variety of products, including telecommunications equipment, thermal insulation, and radiation dosimeters. To establish a laboratory accreditation program, NBS works closely with the appropriate industry to develop the technical requirements and documentation

needed for the accreditation process. For example, NBS sponsors public work- shops to obtain technical guidance from

experts in related industry, government,

and standards-developing organizations.

NBS also works with industry to design

proficiency testing requirements,

including selection of test methods for which proficiency testing is necessary and appropriate, the frequency of profi- ciency testing "rounds," and the artifacts to be tested. Laboratories interested in receiving

accreditation are sent a LAP-specific

handbook that contains the generic

administrative and operational require- ments for accreditation as well as the

specific technical requirements for accreditation and a set of critical elements which defines those aspects of each test method that an assessor must

consider in determining the laboratory's

competence. In addition, the laboratory receives application forms and instruc- tions for providing essential information on laboratory ownership, management,

key personnel, scope and operation, test method selection, instrumentation and

facilities, and other relevant information.

Contact: Harvey W. Berger. A531

Administration Bldg., 301/975-4017.

Contact: Francis W. Wang, B320

Polymer Bldg., 301/975-6725.

48
Radiation Research

Accelerator The NBS accelerator research program is Research aimed at developing advanced particle accelerators for applications in nuclear

physics, free electron lasers, inertial confinement fusion, and dosimetry. The

major focus of this NBS program at present is to establish the feasibility and

provide the technology needed for cw

accelerators by designing, constructing,

and evaluating the performance of a 200- MeV continuous-beam racetrack microtron (RTM) using a room temperature rf accelerating section. In addition, NBS

scientists are attempting to modify this racetrack microtron for use as a free- electron laser driver. To improve industrial applications of

particle accelerators, NBS scientists are

interested in working with industry researchers to evaluate performance and

optimize the RTM design, to design and

develop high peak current and high

brightness injectors, and design and

develop free-electron lasers using the RTM as a driver.

Contact: Samuel Penner, B119 Radiation Physics Bldg., 301/975-5601.

Autoxidation/ The kinetic and mechanistic aspects of Antioxidants autoxidation in foods, organic materials systems, and other biochemical systems;

the design of appropriate antioxidants for the prevention of the deleterious effects

of oxygen; and the extension of the life- time of chemical and biochemical

systems are important to many food,

drug, and medical industries. Wideranging NBS research involves investigations in these general areas: the free

radical chemistry of organic systems and

biochemicals susceptible to autoxidation and free-radical mechanisms and reaction rates of antioxidants, particularly in the case of key components of foodstuffs and other life-supporting substances.

Scientists are studying the effects of parameters such as oxygen pressure, temperature, additives, and concentrations on the optimization of these parameters and the development of products less sensitive to oxidation. NBS researchers are seeking industrial collaboration in the analysis of short- and

long-term intermediate species in pulseirradiated oxygenated organic and

aqueous solutions; derivation of kinetic data and unraveling of auto- and

radiation-stimulated oxidation processes;

and design of new antioxidants as

protective agents against food spoilage,

carcinogenesis, atherosclerosis, and

nitrosamine formation in foods. Kinetic and analytical chemical technologies,

such as GC/MS, HPLC, spectroscopy,

chromatography, electrophoresis, and

ESR spectroscopy; high-intensity gammaray sources, pulsed- and continuousbeam electron accelerators; and various organic-chemical analytical equipment

are available.

Contact: Michael G. Simic, C206 Radiation Physics Bldg., 301/975-5558.

Imaging by use of penetrating radiation is one of the most powerful investigative

techniques available to industry for maintaining or improving the quality of products. Designers are now aware of

this and are creating components which

facilitate such nondestructive testing.

Research is under way at NBS that will allow better quantification of the radio- graphic images. Particularly relevant to image evaluation are computer-based

systems that permit pseudo three- dimensional images and the implementation of image processing on these or

traditional images in real time or near real time. This research focuses on a number of areas, including image processing for improved imaging of low-contrast or noisy images; adoption of tomographic

equipment to industrial needs and measurement of the performance characteristics of such systems; and

development of reliable techniques for image storage and retrieval. For these

projects, available equipment includes x- ray sources, low-energy electron accelerators, and gamma-ray sources as well as

state-of-the-art radiologic imaging

devices.

Contact: Robert C. Placious, C215

Radiation Physics Bldg., 301/975-5579.

The use of irradiation as a food preservation technique has made research into the chemistry of food processing by

ionizing radiations, such as gamma rays and high-energy electrons, important to food industries. NBS is addressing these concerns by studying chemical changes

induced by irradiation processing of food

Industrial Radiologic

Imaging

Food Irradiation Chemistry

49
Radiation Research

Neutron Fluence

Measurement and

Neutron Physics

components including proteins, fats, sugars, and vitamins. In one project, researchers are selecting radiolytic

products which could be used by food processors as indicators to determine

whether foods have been irradiated. Other investigations compare thermal and

irradiation food processing chemistry and

the effect of irradiation processing

parameters, such as dose rate and

temperature, on food chemistry and

quality. Researchers work closely with the Food and Drug Administration and the United States Department of Agriculture

to obtain up-to-date information about

regulatory and safety requirements for foods and food processing and

associated quality control measurements.

Specific areas in which cooperative

research is encouraged include kinetic and steady-state analyses of radiolytic

products in food components, comparison of energy absorption mechanisms in foods, design of post-irradiation quantitative and qualitative analyses of various foods and their components, and

development of food component Stan- dard Reference Materials. Sophisticated

analytical techniques such as GC/MS,

HPLC, spectroscopy, chromatography,

electrophoresis, and ESR spectroscopy

as well as high-intensity gamma-ray

sources, pulsed- and continuous-beam

electron accelerators, and various organic-chemical analytical equipment

are available.

Contact: Michael G. Simic, C206 Radiation Physics Bldg., 301/975-5558.

NBS researchers are studying industrial applications of neutron fluence and dose

determination in the neutron energy

region from thermal to 20 MeV. They are concentrating on the development of effective methods to transfer personnel

protection technology to the private

sector. This research provides a basis for standardizing personnel protection

control procedures in nuclear reactor and

high-energy accelerator operations, for example.

Specific research projects involve: measurement of reference standard

neutron reaction cross sections; characterization of reference fission deposits;

development of neutron detectors with

fast timing; calibrations using standard

neutron and gamma-ray fields; and appli- cations of neutron resonance radiography.

Equipment available includes a 100- MeV linac-based dedicated pulsed

neutron source, a 3-MV pulsed positive- lon accelerator, and a 20-MW nuclear

reactor.

Contact: Oren A. Wasson, B1 1 1 Radiation Physics Bldg., 301/975-5567.

To produce radiation for experimental purposes, NBS has built a synchrotron

ultraviolet radiation facility (SURF-II). SURF-II is a 300-MeV electron storage

ring that radiates high-intensity synchrotron radiation in the energy range from about 3 nm (400 eV) in the soft x-ray region to wavelengths in the visible region of the spectrum. The radiation is highly collimated, nearly linearly polarized, and of calculable intensity. Six beam lines are available and a user's program is in operation. SURF-II is well suited for several different types of research, such as atomic, molecular,

biomolecular, and solid-state physics; surface and materials science; radiation chemistry and radiation effects on matter;

ultraviolet and x-ray optical systems; and

the calibration, characterization, and

development of spectrometers and

detectors. NBS scientists are particularly interested in conducting collaborative research in: the use of soft x-ray synchrotron radiation for high-resolution lithog- raphy; measurement of the reflection characteristics of novel, high-efficiency,

multilayer far ultraviolet optical devices; and calibration, characterization, and

development of spectrometers and

detectors. Other available equipment includes a

state-of-the-art multipurpose detector cali- bration facility, a large ultrahigh vacuum

spectrometer calibration chamber, and a beamlme dedicated to high-resolution

radiation research with a 6.65-m vacuum

spectrometer with a resolving power of about 300,000.

Contact: Robert D. Madden, A249 Physics Bldg., 301/975-3726 or William R.

Ott, B206 Metrology Bldg., 301/975-3709.

Ultraviolet and

Soft X-Ray

Radiation Effects

)
Radiation Research

Optical The U.S. defense, aerospace, health, Pyrometry, lighting, and photographic industries Radiometry, require radiometric measurements for Photometry product development, quality control, and

equity in trade. Compatibility of industrial radiometric standards with national and

international standards is a key requirement to ensure a competitive position in world markets for these industries. To

help ensure reliable radiometric measurements, NBS is conducting radiometric research in the near-ultraviolet, visible, and infrared spectral regions and

developing accurate standards and cali- bration procedures for these regions.

Specific research focuses on calibration

of near-infrared pyrometers; geometrically

total spectral flux standards; detector- based radiometric standards; diode-array

radiometry, photometry, and colorimetry;

low-light-level calibration standards; nearinfrared detectors; infrared spectral radi- ance standards; and absolute spectral

analyzer systems. Available for these

projects is sophisticated optical equip- ment such as tunable dye lasers, electro- optical devices, and interferometers.

and conductivity measurements. Various

x-ray and gamma-ray sources and elec- tron accelerators with energies in the 0.1- to 10-MeV range are employed. In addition, conventional ultraviolet, visible, and

infrared spectrophotometers and spectrofluorimeters, high-intensity gamma-ray

sources, pulsed and continuous beam

electron accelerators, and various organic-chemical analytical equipment

are available.

Contact: William L. McLaughlin, C209

Radiation Physics Bldg., 301/975-5559.

As part of its research to understand and measure various forms of radiation, NBS

is conducting vacuum ultraviolet studies

involving radiation damage, polymerization of organic molecules, and solar simulation. NBS scientists have worked

with industry researchers to develop and

test vacuum ultraviolet instrumentation, new spectrometer designs, and detector systems, especially for flight in space.

Vacuum

Ultraviolet Radiometry

Contact: A. Russell Schaefer, A313

Metrology Bldg., 301/975-2331.

Radiation To enhance quality control methods

Processing employed in industrial radiation processing of foods and the production

and use of medical devices, electronic components, and polymers, NBS

researchers are developing standardization and measurement assurance methods related to industrial high-dose

applications of ionizing radiation. As part

of this program, Bureau scientists are

investigating radiation chemical

mechanisms and kinetic studies applied

to chemical dosimetry systems in the condensed phase, including liquids, gels,

thin films, and solid-state detectors. They

plan to examine such sensor materials as doped plastics, solid-state matrices,

organic dye solutions, semiconductors,

scintillators, biopolymers, amino acids,

metalloporphyrins, and organic or inor- ganic aqueous solutions and gels.

In this research, scientists use a number of analytical methods including transmission and fluorescence spectrophotometry, electron spin resonance

spectrometry, chemiluminescence

photometry, as well as fiber optics analysis, microcalorimetry, pulse radiolysis,

By combining an ultrahigh vacuum, high-resolution scanning

electron microscope with a new, compact electron spinpolarization detector, physicists (I. to r.) Gary Hembree, Robert

Celotta, John Unguris, and Daniel Pierce can observe simultaneously the magnetic character of a surface and its physical

structure over dimensions as small as 100 angstroms.

51
Radiation Research

Standard Reference

Data

They have also collaborated on special sources, narrow band filters, and lasers. Bureau scientists are interested in doing cooperative research in several other areas including studying the platinum-neon hollow cathode lamp as a secondary standard, laser plasmas as secondary standards, and a spark

discharge light source as a secondary

standard. State-of-the-art radiometric facil- ities and advanced optical equipment are

available at the Bureau for these studies.

Contact: J. Mervin Bridges, 301/975-

3228 or Jules Z. Klose, 301/975-3230,

B66 Physics Bldg.

Submicron Well-characterized, focused electron Physics beams are used to interrogate the properties of surfaces and magnetic

materials on a microscopic scale. NBS

conducts a broad-based research program exploring the physics of submicron systems with electron microprobes. The program includes

studies of electron-surface interactions, surface magnetism, electron interaction theory, and electron spin polarization

phenomena. Extensive experimental facili- ties are available for this research,

including sources and detectors of spin

polarized electrons, a scanning electron microscope equipped for secondary elec- tron spin polarization analysis, and a scanning tunneling microscope.

Scanning electron microscopy with

polarization analysis (SEMPA) is a unique

measurement capability developed by

NBS scientists to allow the high-resolution

(-10 nm) imaging of magnetic microstructure independently of surface topography. With this technique, they are studying fundamental magnetic

phenomena, the properties of highdensity magnetic recording media, and

small-particle magnetism. Bureau

researchers are using the scanning

tunneling microscope (STM) to study

surface topography at the atomic level, mechanisms of film growth at the submonolayer level, reconstructions of semiconductor surfaces, and, ultimately, correlation of surface microstructure with macroscopic properties.

Using computers to provide timely and

inexpensive access to reliable chemical,

physical, and materials data contributes

greatly to increased productivity and

lower manufacturing costs of industrial operations. The NBS Standard Reference Data program works closely with industry

to develop the tools and standards necessary for computerizing industrial technical data-the numbers, graphics,

tables, and text that convey research

results. The National Standard Reference Data

System, coordinated by NBS, is a major

focal point in the United States for the

evaluation of chemical, physical, and

materials properties data. The NBS Stan- dard Reference Data program has made

a commitment to provide national leader- ship in the computerization of these

evaluated data, including database

design, data interchange standards, and

data dissemination. NBS research combines expertise in the physical sciences with specialized

knowledge in computer science. Areas of

activity include preparation of databases

of evaluated data and predictive software

for use on personal computers, conversion and combination of published data

compilations into searchable databases,

standardization of formats for scientific information, development of expert

systems, and establishment of distributed systems linking scientific databases. Computer and telecommunications capabilities at NBS offer challenging alterna- tives to the handling of these projects, with state-of-the-art mainframes, minis and micros, database management

systems, graphics, and applications soft- ware available.

Contact: David R. Lide, A323 Physics

Bldg., 301/975-2200.

Computerization

of Standard

Reference Data

Contact: Robert J. Celotta, B210 Metro- logy Bldg.. 301/975-3710.

52 6 U8 OOVERNMENT PR1NTINO OITICB H»t - Ml-097 - 814/S2614
National Bureau of Standards

The National Bureau of Standards was established by an act of Congress on March 3, 1901. The

Bureau's overall goal is to strengthen and advance the

nation's science and technology

and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a

basis for the nation's physical

measurement system; (2) scientific and technological services for industry and government; (3) a

technical basis for equity in trade;

and (4) technical services to promote public safety. The

Bureau's technical work is performed by the National Measurement Laboratory, the National

Engineering Laboratory, the Insti- tute for Computer Sciences and

Technology, and the Institute for Materials Science and

Engineering.

The National Measurement

Laboratory

Provides the national system of physical

and chemical measurement; coordinates

the system with measurement systems of other nations and furnishes essential services leading to accurate and uniform

physical and chemical measurement

throughout the nation's scientific community, industry, and commerce; provides

advisory and research services to other government agencies; conducts physical

and chemical research; develops,

produces, and distributes Standard Refer- ence Materials; and provides calibration services. The laboratory consists of the

following areas:

• Standard Reference Data

• Measurement Services

• Basic Standards

• Radiation Research

• Chemical Physics

• Analytical Chemistry

The National Engineering

Laboratory

Provides technology and technical services to the public and private sectors

to address national needs and to solve

national problems; conducts research in engineering and applied science in support of these efforts; builds and maintains competence in the necessary

disciplines required to carry out this research and technical service; develops

engineering data and measurement

capabilities; provides engineering meas- urement traceability services; develops

test methods and proposes engineering

standards and code changes; develops

and proposes new engineering practices;

and develops and improves mechanisms

to transfer results of its research to the

ultimate user. The laboratory consists of the following centers:

• Applied Mathematics

• Electronics and Electrical Engineering

• Manufacturing Engineering

• Building Technology

• Fire Research

• Chemical Engineering

The Institute for Computer

Sciences and Technology

Conducts research and provides scientific and technical services to aid federal agencies in the selection, acquisition,

application, and use of computer tech- nology to improve effectiveness and

economy in government operations in accordance with Public Law 89-306 (40 U.S.C. 759), relevant Executive Orders,

and other directives; carries out this mission by managing the Federal Infor- mation Processing Standards Program,

developing federal ADP standards guidelines, and managing federal participation

in ADP voluntary standardization activities; provides scientific and technological

advisory services and assistance to federal agencies; and provides the technical foundation for computer-related poli- cies of the federal government. The

institute consists of the following centers:

• Programming Science and Technology

• Computer Systems Engineering

The Institute for Materials

Science and Engineering

Conducts research and provides measurements, data, standards, reference

materials, quantitative understanding, and

other technical information fundamental

to the processing, structure, properties,

and performance of materials; addresses

the scientific basis for new advanced

materials technologies; plans research around cross-country scientific themes

such as nondestructive evaluation and

phase diagram development; oversees Bureau-wide technical programs in nuclear reactor radiation research and

nondestructive evaluation; and broadly

disseminates generic technical information resulting from its programs. The insti- tute consists of the following divisions:

• Nondestructive Evaluation

• Inorganic Materials

• Fracture and Deformation

• Polymers

• Metallurgy

• Reactor Radiation