US. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

NBS SPECIAL PUBLICATION 719

QC

100

.157

N0.719

1986
Cover photo: Through the use of very thin films and

detailed surface analysis,

Dr. Stephen Semancik and

his colleagues have charac

terized the surface adsorption properties of tin oxide.

Such Information can be

used to improve tin oxide

sensors. See page 16.
CONTENTS

Reports

Research Update 2

Spirit of Cooperation Alive and Well

at National Bureau of Standards 4 Taking the Earth's Measure at a Unique Institution 9

Gravity, When You Get Right Down to It . .

.

1 1 The Light Fantastic 12

Safer, Quicker Ways to Prepare

Samples for Chemical Analysis 14 Researchers Study the Process to Improve Measurement Accuracy 16

Expanded Version of IGES Standard Available 21 NBS Studying New Technique to Identify Irradiated Foods 22

NBS Research in Biotechnology: Providing

the Scientific Fundamentals 24

New Publications 30

Conference Calendar 32

U.S. DEPARTMENT OF COMMERCE

Malcolm Baldnge, Secretary

National Bureau of Standards

Ernest Ambler, Director

National Bureau of Standards

Gaithersburg, MD 20899

301/921-1000

National Bureau of Standards

Boulder, CO 80303

303/497-3000

July 1986

NBS Special Publication 719

Prepared by the Public Information Division A903 Administration Building

National Bureau of Standards

Gaithersburg, MD 20899

301/921-3181

Library of Congress

Catalog Card Number:

86-600556

CODEN XNBSAV

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. 1
RESEARCH UPDATE

mmmmmmmmmamm

BS, QINT DATABASE SYSTEMS

TO STUDY "DATA

ENGINEERING" TOOLS NNBS and QINT Database

Systems Corporation have

begun a joint research program to develop an "Information Engineering Workstation"

to complement the NBS Automated Manufacturing Research Facility (AMRF) project. QINT, which sells an automated software package implementing a sophisticated data

analysis methodology and providing a

formal representation for it, will assist NBS

researchers in adapting and extending their analysis tools for use with the NBS

Integrated Manufacturing Data Administration System (IMDAS). The QINT tools ensure that the implemented databases

accurately reflect the data analysis. The

Information Engineering Workstation, using

graphic aids, will allow an analyst to define the data shared within the AMRF and

generate automatically the data structures necessary for IMDAS data directories and

databases. Gail Vermilyea and B. Benita Ranghel of QINT will work with the NBS

Factory Automation Systems Division under

the Bureau's Research Associate Program.

Through the NBS Research Associate Program, researchers from industry and

other sponsoring organizations, whose

salaries are paid by their sponsors, work at NBS on projects of mutual interest. P

ROCESS CONTROL SENSOR

GOAL OF COOPERATIVE

PROGRAM

The Aluminum Association and

NBS have agreed to a cooperative research program to develop a pro- cess control sensor for the manufacture of extruded aluminum products. Extruded

shapes, bars, pipes, and rods represented

nearly one-fifth of the estimated 15.2 billion pounds of aluminum shipped by industry in 1985. As a part of the agreement, a

research associate sponsored by the Aluminum Association will work at the Bureau evaluating and using NBS research

results to develop a "noncontact" process

control sensor for measuring internal temperatures during the rapid extrusion of aluminum alloys. The second phase of the cooperative program calls for installing a prototype sensor at a plant for field evaluation with an aluminum extrusion process. Instrument

builders wili be offered opportunities to participate in the demonstrations and to investigate the sensor's performance with various automated process control systems.

The sensor also will be evaluated for use in controlling temperatures in other areas of aluminum processing such as the pre- heating of billets and ingots, at quenching

facilities, and for controlling continuous

casting.

NDERWRITERS

LABORATORIES, NBS AGREE

ON JOINT PROGRAM

EW MATERIAL TO IMPROVE

MEASUREMENTS OF PCB

LEVELS IN BLOOD

Tests for amounts of polychlorinated biphenyls (PCB's) in blood samples can be checked for accuracy with a Standard Reference Material (SRM) available from NBS. Such tests are important for determining exposure of persons who work with toxic PCB com- pounds—employees in the chemical industry or emergency personnel who clean up

chemical spills, for example. SRM 1589 is

in the form of freeze-dried human blood serum "spiked" with 106 nanograms of Aroclor 1260 per gram of serum. (Aroclor 1260 is a mixture of PCB's found in some transformer oils). The SRM is intended for use in the calibration of analytical instruments and validation of a

laboratory's procedure for measuring PCB's in blood. It also may be used as a

primary standard against which secondary

reference materials may be compared.

Certified to be accurate within a 1 percent

range, the SRM costs $163 per three-vial

set. To order SRM 1589, Polychlorinated

Biphenyls (as Aroclor 1260) in Human

Serum, or for more information about the more than 900 SRM's the Bureau offers for sale, contact the Office of Standard

Reference Materials, B311 Chemistry

Building, NBS, Gaithersburg, MD 20899,

301/921-2045.

^|^^^ Underwriters Laboratories is * sending one of its researchers

to work at NBS laboratories to study false alarms by smoke detectors. While detectors are used in millions of residences as

well as commercial and institutional buildings, false alarms from the detectors reduce their effectiveness and consumer

confidence. The research, which will be

conducted under the NBS Research

Associate Program, will involve visits to selected installations that have experienced problems and testing at NBS and

other facilities. It also will include

identifying problems and coordinating

activities with equipment manufacturers,

testing laboratories, and standards and

code organizations. Through the NBS

Research Associate Program, researchers from industry and other sponsoring

organizations, whose salaries are paid by

their sponsors, work at NBS on projects

of mutual interest.

BS VALIDATING COMPUTER M_»„ SECURITY DEVICES

,

for Computer Sciences and

Technology have completed the

first validation of a security device that will be used to authenticate electronic funds

transfer messages. The validation program

is part of an agreement signed by NBS,

the Department of the Treasury, and the

National Security Agency (NSA) in March

1985 to help protect the billions of dollars

in federal funds that are transferred

electronically each year. Based on technical guidance from NBS and NSA, the Treasury

Department will certify that electronic funds

transfer devices are designed properly and

security features called for in a 1984

Treasury Department directive have been

incorporated.

NBS developed the test methods to validate that the devices comply with federal and industry standards (Federal

Information Processing Standard 113, Computer Data Authentication, and

American National Standard for Financial

Institution Message Authentication

2
[Wholesale]). The validation system can be

used to test equipment remotely through an electronic interconnection with NBS. For

further information or to validate security

devices, contact Miles Smid, A216

Technology Building, NBS, Gaithersburg,

MD 20899, 301/921-3427.

MPROVED GC/MS METHODS AID STUDY OF DNA RADIATION

DAMAGE

A novel application of analytical techniques allows NBS researchers to achieve very high levels of sensitivity in their study of radiation-induced damage in DNA. Identification and measurement of radiation-altered biomolecules is part of an

overall NBS program to understand the fundamental physical and chemical inter- actions of ionizing radiation with matter. The

quantitative measurement of these molecular alterations is a necessary first step in learning how ionizing radiation causes changes in DNA that might have

detrimental consequences in living cells. Radiation chemist Miral Dizdaroglu has

detected altered nucleosides in DNA molecules irradiated at doses as low as 1 Gray

(100 rads) in concentrations as low as 10 femtomoles (0.01 part per trillion). Dizdaroglu's method involves using

enzymatic hydrolysis to break down DNA

to its component nucleosides. Combined

gas chromatography/mass spectrometry

with selected ion monitoring (SIM) is then used to identify those species altered by exposure to radiation. The use of the mass

spectrometer's SIM mode requires that the mass spectrum of the DNA nucleoside under investigation and its gas chromatographic retention time be known in advance, but allows at least a 100-fold increase in sensitivity. This permits study of nucleosides at very low concentrations in mixtures too complex for analysis by gas chromatography alone.

ENSOR DEVELOPED TO

IMPROVE QUALITY CONTROL

OF PROCESSED METALS

A new ultrasonic sensor for measuring the depth and properties

of treated steels and metal alloys has been

developed at NBS to improve quality control of processed metals. The sensor,

which uses ultrasonic waves to make very

precise measurements of both the depth

and mechanical properties of surface- modified layers, eliminates the need to destr oy finished products to determine the

effectiveness of processes used to modify

metal surfaces and the quality of the component. The sensor was developed by

two guest workers from Johns Hopkins

University, Dr. Moshe Rosen, professor of materials science, and graduate student

Bret J. Elkind and NBS scientist Dr. Haydn

N.G. Wadley. The sensor has been evalua- ted in a series of laboratory tests at NBS to

verify its accuracy and performance. The

researchers anticipate the new ultrasonic sensor will become an important measure- ment tool for manufacturers using nondestructive evaluation techniques to improve the quality control of their products.

| EFERENCES AVAILABLE FOR

MEASURING AIRBORNE

BERYLLIUM AND ARSENIC

Laboratories that analyze levels

of beryllium and arsenic in industrial atmospheres can check the accuracy of their equipment and analytical methods with a Standard Reference

Material (SRM) available from NBS. Tests

to determine airborne levels of these two

potentially toxic metals in workplace

environments—in certain mining and

pesticide industries, for example—are

crucial for monitoring worker exposure and are required periodically by the

federal Occupational Safety and Health

Administration. The new NBS material, Beryllium and Arsenic on Filter Media

(SRM 2677), will allow verification of such

tests. It is designed to be run through the same chemical tests as an actual air sample collected on a filter. The SRM,

which contains two identical sets of four mixed cellulose ester membrane filters, is certified for accurate amounts of beryllium

and arsenic composite at three different

levels. Included in the sets are two "blank"

filters to gauge the ambient levels of beryllium and arsenic in the laboratory

where the analysis is made. SRM 2677

costs $118 and is available from the Office

of Standard Reference Materials, B311

Chemistry Building, NBS, Gaithersburg, MD

20899, 301/921-2045.

OOPERATIVE RESEARCH

AGREEMENTS FOR SEMPA

FACILITY SOUGHT

NBS is seeking firms interested

in cooperative research agree- ments to further develop and exploit the Bureau's new facility for scanning electron microscopy with polarization analysis

(SEMPA). SEMPA allows the simultaneous

observation of surface microstructure and

surface magnetic domains at the resolution

of electron microscopy (0.01 micron),

using an innovative, extremely compact

electron spin detector invented at NBS. The

Bureau's unique SEMPA facility can be

used for research in magnetic thin films, high-coercivity magnetic materials, highdensity magnetic storage media, and other advanced magnetic materials. NBS would

like to set up joint research programs on

projects of mutual interest on a cost-sharing

basis. For more information, contact Dr. Robert Celotta, B210 Metrology Building,

NBS, Gaithersburg, MD 20899, 301/921-

2051.

EST METHOD FOR PHYSICAL

LAYER PROTOCOL BEING

DEVELOPED

The NBS Institute for Computer

Sciences and Technology (ICST)

is developing a test method to ensure that modem and head-end equipment from

different manufacturers can communicate

using an IEEE standard (802.4 Broadband

Token-Passing Bus physical layer protocol). By transmitting and receiving various test frames, modems from various manufacturers will be tested against head-end

equipment from other manufacturers. The

equipment, donated by industry, will be

tested in ICST's local networking laboratory.

NBS has been working with industry and

standards groups for several years to make

it possible for computer systems or equipment to communicate with each other regardless of who manufactures the

individual pieces. The NBS test methods

make it possible for vendors to know

whether the complex "protocols," or rules which make possible multi-vendor computer-to-computer communication, are being implemented correctly.
Spirit of Cooperation Alive and Well

at National Bureau of Standards

e want to be sure our research is helping industry solve its measure- ment problems, and one of the most effective ways to accomplish

that is through cooperative pro- grams," says Dr. Ernest Ambler,

director of the National Bureau of Standards. 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

robotics, computer networks,

clinical chemistry, and ceramics. The arrangements are mutually

beneficial. "Successful relations between government and the pri- vate sector don't have to be based

on grants and government

giveaways," says Dr. Donald

Johnson, director of the NBS

National Measurement Laboratory. "Our experience at NBS is that these programs work best when

both sides are involved in a

personal way, supplying staff and

resources, and when both sides

get something they want out of the

relationship."

The visiting researchers get an

opportunity to work with the

scientists and engineers at NBS,

many of whom are renowned

experts, and to use the Bureau's

premier research and testing

facilities. They then can take the newly developed technology back

to their organizations to be incor- porated into new ideas, new

processes, and new products. Says

Ambler, "They come to NBS to conduct research, but they also come to learn how they can put our work to use." NBS gains from

these cooperative programs by

learning firsthand the views and

needs of industry. "To ensure our domestic strength

and to compete successfully with other nations, we must exploit our knowledge and technology. That

means we must make the most of our research resources—both our equipment and our people," adds

Ambler. "Cooperation in research and development is one obvious

answer. We at NBS have made co- operation with industry a way of doing business right from the start, and now, to help meet these eco- nomic challenges, we are working

to do even more." As the only federal laboratory

with the explicit goal of serving U.S.

industry and science, NBS uses a wide variety of mechanisms to transfer its expertise in measure- ment technology to those who

need it.

Robots and Computers

Private companies, universities, and

other government agencies are working with NBS to develop the Automated Manufacturing Research

Facility (AMRF). The AMRF, a

research testbed for the factory of the future where robots and

machine tools work together under

"We at NBS have made

cooperation with industry a way of doing business

right from the start, and

now, to help meet these

economic challenges, we

are working to do even

more."

computer control, is being built at NBS to study fundamental questions affecting factory automation. Questions that affect the modernization and competitiveness of American industry. Since 1 982, 35 companies 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 Auto- mation Project and other govern- ment 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 experimenting with methods for getting robots, computers, and

machine tools from different manufacturers to communicate and

work together in an integrated

system. Their other primary goal is to find a means for controlling

quality in a fully automated factory environment.

All of this will give companies, in particular 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

interfaces. According to a study by the Management Collaborative Group

of Chapel Hill, N.C., the contri- bution of the AMRF to the in- creased use of numerical-control (NC) machine tools in U.S. industry will produce a savings to the metalworking industry of between

$250 and $760 million per year by 1990. The study also predicts

that the U.S. Navy's support of the AMRF will improve defense

readiness. It says the annual Department of Defense procure- ment savings generated by in- creased use of NC machine tools, resulting from the AMRF work, will total an estimated $154.8

million—four times the Navy's total projected investment—by the end

of 1989. American companies are already adopting the ideas and

techniques of the AMRF. One

company has adapted NBSdeveloped error-correction techniques to the control system

of its machining centers.
Another has developed a version of "Drill-Up"—a device built by NBS

engineers to help sense when a

drill bit is about to break. And the

U.S. Navy is now undertaking a model project to transfer the technology into a Navy shipyard.

In another program, NBS is parti- cipating in the international effort to establish computer networking stan- dards to improve communication

among different computers. Since

1979, NBS has been doing the

technical spade work—developing

the data, testing the theories, making sure proposed standards

will work—to aid in the voluntary standards development process. In this effort, NBS computer experts

have worked closely with industry

and standards groups: Over the

past several years, visiting researchers from about 25 companies such as Intel, General

Motors, and Honeywell have aided

in the development of networking standards as well as test methods

needed by industry to determine

whether the standards have been

used correctly, thus enabling

different manufacturers' equipment

to work together.

NBS also has been instrumental

in getting these standards and test methods out of the laboratory and

into use through workshops to transfer the technology to the vendors and users. More than 1 75

companies and organizations have

participated in these workshops.

The technology has been used

successfully at two major showings:

the 1984 National Computer Conference and the 1 985 Autofact

exhibit. Industry also has adopted

the technology as standards for the

plant floor and engineering and

office environments. Both the Manufacturing Automation Protocol (MAP) and the Technical and Office Protocol (TOP) were demonstrated

at the Autofact exhibit. Says Mike Kaminsky, manager of the MAP program at General

Motors, "It's my firm belief that

Bpf . """\

\

f

y

At the horizontal workstation in the NBS Automated Manufacturing

Research Facility, Christopher Stevenson (left) of White-Sundstrand

and Howard Harary of NBS discuss the next generation of machine

tools.

5
NBS metallurgist Floyd A. Mauer (left) and David Rogers, AISI research associate from U.S. Steel, are working on sensors to improve steel production.

without NBS involvement in devel- oping and testing these standards and getting them accepted by

vendors and users we would not be at the point we are today. NBS

has been the catalyst that has

brought all this together...."

"It is really a two-way street," adds Dr. John Heafner, chief of the Systems and Network Architecture

Division at NBS. "The companies

have a vested interest in making it easier for computer systems and

equipment to communicate—it's vital to the industry. And we can't

afford to work on these kinds of projects without knowing what

industry is doing and how we can

best serve them. We need industry's involvement, and key

companies are making the kinds of contributions that will mean our work will pay quick dividends." Improving Steel and

Clinical Measurements

For years NBS and the metals

industry have collaborated to

improve the durability and per- formance of metals and alloys. As

early as 1903, NBS was working to determine the melting points of pure metals as a part of the Bureau's mission to perform basic measurements.

Today, the American Iron and

Steel Institute (AISI), the American

Society for Metals, the National Association of Corrosion Engineers,

and others are sponsoring re- searchers to work with NBS scientists and engineers on generic

technology and reliable data to upgrade the quality of metals and

improve productivity for the metals

industry. For instance, AISI is currently

sponsoring five researchers from

United States Steel, LTV Steel, and

Bethlehem Steel Corporation in a

project to develop a new sensor

that promises to save steel mills millions of dollars. The sensor

technique should enable steel producers to detect quickly flaws in hot metal and more accurately crop

unsound material before it is run through the complete production

cycle. The sensor has been tested successfully at the Argonne

National Laboratory, a Department

of Energy facility, and in the near

future will undergo final tests in a

steel mill. Dr. Lyle H. Schwartz, director of the NBS Institute for Materials Science and Engineering, says, "This cooperative program between

industry and two national laboratories gave the private sector an

opportunity to participate at the very beginning of the research

process. This will help to ensure acceptance of the research results and assist in the successful

transfer of the technology to users. Technology transfer is the

vital link in the research process."

In some cases, NBS works with a group, or consortium, of companies to solve a particular problem. For example, NBS and

several companies have joined in an effort to better clinical measurements. The focus of this joint agreement is the measurement of two elements—sodium and potas- sium—important in clinical tests because of their roles in high blood pressure, heart disease,

and general health. The National Committee for Clinical Laboratory

Standards, on behalf of the cor- porations, has sent a researcher

to NBS as part of the agreement.

Major questions about measuring

these elements are being examined. The industrial consortium,

which includes instrument manufacturers and others involved

with clinical measurements, is contributing funds for the project.

Biotechnology and

Astrophysics

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

County, Maryland, are establishing a Center for Advanced Research in
Biotechnology (CARB) to provide a

forum for collaborative research among academic, government, and

industrial scientists. "We will focus on establishing the world's finest

facility for determining and analyzing the structure of macromolecules," says Dr. Kevin Ulmer,

director of the center. "The ultimate goals of CARB's research are to

radically reduce the time and effort required to determine the atomic

structure of proteins and to

effectively model and predict their properties."

CARB researchers will draw

upon the expertise at NBS in physical and chemical measurement technology and will have

access to unique research facilities including the Bureau's research

reactor and supercomputer. The

center will house scientists from the

University of Maryland and NBS as

well as a large population of visiting scholars, industrial fellows, and

graduate and postdoctoral students. Eventually about 130 scientists are expected to be working at the

center.

Hiring of senior research

scientists for CARB is under way

and construction of the building,

being financed by Montgomery

County, is scheduled to begin this

fall.Although the biotechnology

center agreement is unique, NBS

has a long history of cooperative

research with universities. Witness

the 24-year-old enterprise known as

the Joint Institute for Laboratory

Astrophysics—or J I LA—formed

between NBS and the University of Colorado. (See article on page 9.) J I LA was originally created to help

provide sound laboratory tech- niques and measurements needed

by space scientists to understand

the behavior of atoms or molecules

in different atmospheres. The work

of JILA scientists has been used in a diversity of practical applications

from the design of new, more

powerful lasers to the building of high-voltage electrical generators

and more efficient street lights. A permanent Ph.D. staff of 22

"fellows" manages the day-to-day

operation of JILA—8 are full-time university faculty and 14 are NBS

scientists. But through a rather complicated system that brings

together renowned scholars from around the world, graduate and

postdoctoral students, and visiting scientists, NBS gets the benefits of the work of 1 60 people. The university gains a large community of international scholars and a

substantial adjoint faculty which

trains graduate students, teaches

courses, and serves on committees.

Sharing Facilities

Most of the Bureau's research and

testing facilities are available for cooperative research by the scientific and engineering communities,

and, in certain cases, companies

can use NBS facilities for proprietary research. "We have

decided to make selected NBS

facilities available to U.S. researchers for proprietary work on a cost- recovery basis, when equal or superior facilities are not otherwise

available," says Ambler. "We hope

this policy will increase the transfer

of technology to industry and

encourage commercially important research that might otherwise not be done." Three hundred people from 60

institutions, including other government agencies, universities, and industry, conduct research

annually at the NBS 20-megawatt

research reactor, which is available

for both cooperative and proprietary research. The Food and Drug

Administration, for example, uses

the NBS reactor to measure small

quantities of toxic materials in food, drugs, laundry aids, and cosmetics. The Smithsonian Institution has

used it to examine works of art, E.I, du Pont de Nemours and Company

to measure trace elements in Teflon, and General Electric Company to study tiny flaws in jet engine turbine blades. NBS is now installing a cold- neutron source at the reactor that

will improve greatly its effectiveness and versatility. With the cold- neutron source, researchers will be able expand studies in materials research to include investi- gations of magnetic properties of new advanced alloys; measure- ments of crack growth or the nature of voids in new, experi- mental ceramics; and the distri- bution of "doping" elements in

CARB researchers will

draw upon the expertise

at NBS in physical and

chemical measurement

technology and will have

access to unique research

facilities.

semiconductor materials in concentrations below 1 part in a

million. A unique agreement between

NBS and Exxon Research and

Engineering Company calls for the development of a new small- angle neutron scattering (SANS)

instrument at this cold-neutron

source. SANS is a method of using relatively low-energy

neutrons as probes to measure

the structure of materials in very

great detail. The new instrument

will offer a more extensive range

of capabilities than the existing

SANS at NBS. Exxon and NBS

each will have the right to one-third

of the available time on the instru- ment and the remaining one-third

will be available for use by third parties. NBS has just developed a brand new facility for studying advanced
Whom to Call

One of the most popular ways to make NBS research and facilities accessible to U.S. industry is through the 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 including robotics, computer networks, dental materials, and ceramics. For further information, contact the Office of Research and Technology Applications—301/921-2226.

Proprietary Facilities

While most NBS facilities are avail- able for cooperative research, in 1985 the Bureau opened up some

of its unique 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. One facility which is available for proprietary research is the NBS

research reactor. It is used to conduct research in a variety of areas such as materials science, element analysis, and nondestructive evaluation. Twenty-five experi- mental stations are available at the

reactor.

In addition to the reactor, NBS

has made available a large environ- mental chamber and an electron

linear accelerator (LINAC). The

environmental chamber is capable

of accommodating objects up to the size of a two-story house under

simulated environmental conditions,

and the LINAC provides the

capability for conducting precision research with high-energy beams of

electrons, photons, and neutrons and for developing measurement

standards for these types of radiation. The LINAC presents

special opportunities for small businesses that lack ready access

to radiation-processing facilities. For

further information, contact the NBS

Program Office—301/921-3137.

Other Arrangements

For information on arranging a

cooperative program in a particular research area at NBS, contact the

individual institute or laboratory:

Institute for Materials Science

and Engineering, 301/921-2891:

Provides measurements, data, standards, reference materials, and

other technical information regarding materials to industry,

government agencies, universities, and other scientific organizations. National Measurement

Laboratory, 301/921-2828: Provides

the national system of physical and

chemical measurements;

coordinates the system with measurement systems of other

nations; and furnishes essential services leading to accurate and

uniform physical and chemical measurements throughout the

nation.

Institute for Computer

Sciences and Technology, 301/921- 3151: 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, 301/921-3434:

Conducts research in engineering

and applied science. Studies problems in electronics, manufacturing automation, chemical engineering, the behavior (and

prevention) of fires, and the design

and construction of buildings.

magnetic materials and would like to set up joint research programs on projects of mutual interest on a

cost-sharing basis. The SEMPA

facility (Scanning Electron Microscopy with Polarization Analysis) allows researchers to observe simultaneously the magnetic character of a surface and its physical structure over dimensions

as small as 100 angstroms (10 nanometers). This new research

tool is expected to have important

applications in a number of fields, including the development of highdensity magnetic recording media

and small, high-efficiency electric motors. These are just a sampling of the many cooperative research pro- grams that NBS has with industry, academia, and other government

agencies. NBS also provides other

opportunities to transfer the Bureau's expertise in measurement

technology to those who need it. Literally hundreds of conferences,

workshops, and seminars are held each year by NBS. Bureau

researchers publish their work as

broadly as possible and work

actively with professional and

technical societies and standards

organizations. Using videotapes to explain NBS research enables

others who cannot visit NBS or attend conferences to take advantage of NBS research. In addition, many of NBS' databases and

experts are being made available through computer technology, so

that others will be able to tap into even more information. While NBS Director Ambler is proud of the Bureau's record of cooperation, he would like to pursue more avenues for joint research and services. "By

increasing industry's access to our advanced measurement capabilities, we hope to help industry

improve its products and processes and thus its international competitiveness."

by Jan Kosko

NBS Public Affairs Specialist
Taking the Earth's Measure

as the distance from the center of the Earth changed? Can we measure that change to the nearest centimeter? Why does the aurora

borealis glow the way it does? How

do you build an instrument

1 ,000,000 kilometers long to measure gravity waves?

What's the best gas to use in high-intensity outdoor street lights? What, for that matter, is darker than dark? How do you tell if terrorists are tunnelling into a nuclear weapons vault? You might guess that this jumble

of questions arose from the writing

of a multi-volume encyclopedia. In fact, they represent only part of the unexpected diversity of research

topics at a unique, little-known organization—the Joint Institute for Laboratory Astrophysics in Boulder,

Colo. The "joint institute" part is easy

enough. J I LA, as it is called around

the world, is a 24-year-old cooperative research effort between the

federal government's National Bureau of Standards (NBS) and the

state-run University of Colorado

(CU). Laboratory astrophysics?

That's a bit harder. "When J I LA was first founded it was a child of the space program,"

explains Dr. Katharine Gebbie, who

manages the NBS half of the

institute. "We were going to be

sending up rockets, looking at stars and the Earth's atmosphere. A

study by the National Academy of Sciences about 1960 pointed to serious gaps in our basic under- standing of the behavior of atoms and molecules in atmospheres, whether on Earth, other planets, the Sun, or stars." J I LA was originally created to help fill those gaps by providing the sound laboratory techniques and measurements needed by space

scientists.

In much of this research, the

basic idea is simple (although the

details are rather difficult). Atoms

and molecules can be distinguished

by their spectra—the characteristic frequencies in the electromagnetic

spectrum that they emit or absorb. Since all we really know about a

star is its apparent electromagnetic

spectrum and its position in the

sky, spectroscopy becomes an ex- tremely important tool for astronomy

and astrophysics. Spectroscopy can tell us much more than simply

what atoms are present in a gas. Energy levels, temperatures, and

chemical and physical reactions can all be deduced from spectra, given that you know what to look

JILA was originally

created to help fill those

gaps by providing the

sound laboratory techniques and measurements

needed by space

scientists.

for. And much of the research is just as useful on Earth as in outer space. Knowing what to look for—and

how—is JILA's speciality. Since the

1960's, national needs and priorities have changed somewhat and

JILA has changed to meet those

needs, but observing how gases

radiate under different conditions,

and deducing from that what's in them and what's going on, remains a fundamental part of JILA's work. The institute's work in atomic and

molecular physics is recognized by

scientists around the world.

Cooperative Management

Far from being a pyramid, the JILA

organization chart more closely resembles New York's World Trade

Center. Day-to-day management is handled by the 22 JILA "fellows," the permanent Ph.D. staff, headed

by an elected chairman or -woman, much like a university department.

By tradition, the chair alternates

between NBS and CU employees

and is changed every 2 years. Above that level, it gets more

complicated. Employees of NBS

answer (with one exception) to Gebbie, chief of the NBS Quantum

Physics Division, and through her

to the NBS hierarchy. The one

exception reports to the Bureau's Time and Frequency Division. CU

employees answer variously to the

university's departments of chemistry, physics, or astrophysical,

planetary and atmospheric

sciences. To complicate matters

slightly, NBS fellows hold adjoint

appointments in one of those three

university departments.

All of this is to impress the point

that it's amazing the institute works

at all. In fact, it works very well. The

single biggest advantage of the ar- rangement is the synergism created when two research institutions pool their resources, according to JILA staffers. "JILA is unique in being a

collaboration in which the govern- ment and the university participate as equal partners," observes

Gebbie. "Everyone is very aware

of the need to respect each

other's prerogatives."

Dr. Carl Lineberger, a chemical

physicist from CU, is the current JILA chairman. "It is very difficult for a university, or an organization

like NBS, to put together the

critical mass of people in any

single field that becomes a worldclass institution. You generally

have to balance your resources across many different fields," he

notes.

"In the fields represented at JILA, the university is much

stronger than it could otherwise

be," continues Lineberger. "There

is absolutely no question that we

do better in getting talented students and post-docs, and in attracting and retaining faculty, than

9
we would do in the absence of JILA." "Through JILA both NBS and

CU enjoy a concentration of topflight researchers that neither

institution could support on its own," Gebbie agrees. One of the important contri- butions that NBS makes to the

institute is the visiting fellows program, which each year brings in about 1 0 senior scientists from

research institutions around the world to work at JILA—and there is a lot of competition for the

positions. From its participation in JILA, the Bureau gets enormous research

"leverage." With a comparatively

small division of only 19 people in

all, NBS gets the benefits of the work of a much larger number of people. Counting grad students, post docs, visitors, and visiting fellows, there are 160 people in JILA, including 127 scientists. The NBS members of JILA are unanimous on the advantages of the university atmosphere. "NBS is as healthy a federal lab as there is because of its good mixture of immediate and futuristic research, but you need constant exposure to new ideas. There is no other place besides a university where you have such a constant cross-current

of high-level activity. In post-docs, we get applications from the best of the best," says Dr. John Hall, himself a world-known authority on

lasers. Dr. Gordon Dunn is an NBS

physicist who has contributed

several new techniques and

instruments to the study of how

ions interact with atomic and sub- atomic particles, processes that account for the behavior of much

of the universe. One of the more

recent accomplishments by his team—a way of measuring ion- molecule reactions at extremely low temperatures—has been called

"the most important recent development" by a reviewer in the

field. Dunn credits much of this pro- gress to the JILA atmosphere, observing, "The people I've worked

with over the years—students, post- docs, and visiting fellows— have

played major roles in all we've

accomplished. My group now

includes four students, a post-doc,

and a visiting fellow, and they're all here for only a short period of time. There are a lot of personnel

changes, so you get a constant

influx of new ideas at a substantially

reduced cost to the Bureau."

Life in the Labs

What does JILA study? Things that happen in gases on a molecular

scale and precision measurements

on a planetary scale. Chemical physicist Dr. Stephen

Leone, for example, has been

"JILA is unique in being a

collaboration in which the

government and the university participate as

equal partners," observes

Gebbie.

studying the ion chemistry of the aurora borealis, the northern lights. The issue was what sort of reactions are responsible for the

aurora's rapid shifts of color from

red to green. Leone and his colleagues

developed sensitive measurement

techniques to isolate particular reactions that had long been

suspect and to determine how

much each reaction contributed to the phenomenon. The answers

invalidated some widely held

theories. Who cares? Well, in addition to the acquisition of pure knowledge,

the information is useful to the Air

Force because the same effects

interfere with sensitive detection systems. Leone, incidentally, is a good

example of the return on invest- ment NBS gets from JILA. On the Bureau's books, Leone is a single research scientist. When you count

in his graduate students, post-docs,

and visiting scientists, Leone turns out to be leading a high-powered group of 16 researchers. The typical JILA research topic

sounds fairly arcane—work in its labs tends to be at the measure- ment frontiers of basic researchbut the applications are often quite practical. For example, what are the energy characteristics of collisions between ions in highly excited

states? How do those characteristics depend on the temperature

and density of the gas?

The answers to those ques- tions—which have required the

invention of new measurement

techniques—have immediate use

in problems as diverse as

studying the behavior of stars; designing new, more powerful

lasers; understanding what is going on in experimental fusion energy systems; building highvoltage electrical generators and

switches; and designing the most

efficient street lights. A great deal of JILA's work

bears on the development and

use of the laser. In the 1960's, the

laser was an exotic device used

for classroom demonstrations in physics. JILA researchers share in large part the responsibility for the

laser's modern status as a precise instrument for measurement

science. JILA scientists have invented

several new types of lasers, developed methods of measuring

their performance, made some of the first fundamental discoveries on how to stablize the output of lasers, contributed basic research data Continued on page 13
Gravity, When You Get Right Down to It . .

.

How much a pound weighs de- pends on mass and acceleration due to gravity. Mass is constant; the acceleration due to gravity

changes, depending on how far you are from the center of the

Earth, the density of the Earth under you, the planet's spin, and

so forth. JILA's Dr. James Faller has

spent the last 2 decades

studying gravity and ranks as one of the world's authorities in the field. One project has been

the design and development of an extremely sensitive, portable instrument for measuring the

local acceleration of gravity—

"little g." To a degree, measuring the

local gravitational acceleration is equivalent to measuring how far you are from the Earth's center

at any given place. Working at accuracies in the neighborhood

of 4 or 5 parts in a billion, Faller can detect changes in the dis- tance to the center of the Earth

to within 2 or 3 centimeters. Why do we care about little g? "For one thing," says Faller,

"little g is important to people

who work with fundamental constants of nature. The value of the standard unit of electric current, the ampere, depends

on little g, and so do all of the

other electric units that depend

on the ampere."

Little g affects the accuracy of basic units in mechanics, electricity, thermometry, and fluid dynamics, so standards laboratories are vitally interested in it.

Geologists and geophysicists are also interested, says Faller, because his instrument provides

the equivalent of "a not-terribly- expensive meter stick nailed to the center of the Earth." In earthquake-prone regions it provides an extremely accurate measure of how much the

Earth's crust is moving. Because little g also depends

on the density of the Earth, it's a

useful tool in minerals exploration. Faller has already built one of his gravity meters for use by the Canadian Department of Mines, Minerals and Resources

in prospecting.

Faller and his team of grad- uate students are also working on an imaginative new version

of the classic Eotvos experiment,

in which masses suspended

from a torsion pendulum are used to test one of the funda- mental principles of the general

theory of relativity—that a feather and a lead balloon will fall at the same rate in a vacuum. In Faller's version, a float in a tank

of purified water and an

arrangement of electrostatic

fields take the place of the

traditional torsion pendulum.

Although the experiment is a

classic piece of pure research,

at the astonishing levels of accuracy reached in Faller's lab, the apparatus could have very

practical applications. It is sensitive to nearby changes in mass, detecting, for example,

the presence of a couple of additional bodies in the laboratory, or the departure of crowds

Dr. James Faller of NBS

and the Joint Institute for

Laboratory Astrophysics,

with the JI LA absolute

gravity meter.

from a concert at the university

stadium two blocks away. One possible application, says

Faller, is in detecting the presence of tunnellers burrowing

into bank vaults or nuclear weapon stockpiles. "The thing about security systems is that, in general, if you know what detectors are being used, you can

shield yourself from them," says

Faller. "Except gravity. It's very

difficult to shield yourself from

gravity."
Dr. John Hall of NBS and the Joint Institute for

Laboratory Astrophysics with some of the apparatus

used in his work on frequency-stabilized lasers.

The Light

Fantastic

That the laser has become an

ubiquitous tool in laboratories around the world is in no small measure due to the efforts of Dr. John Hall and his colleagues in Boulder.

Hall's interest in the laser began in the early 1960's, with experiments to measure the speed of light. The work re- quired a very stable laser—one

that produced light at a sharply defined frequency. They used

the best, most stable laser available at the time, and it was

none too good.

Hall and his colleagues at JILA and the NBS Time and

Frequency Division turned their efforts to developing better techniques to stabilize lasers, tying the laser output to narrowly

defined spectral lines in molecules like methane. "Over

the course of 6 years," says

Hall, "and over a succession of post-docs and visiting col- leagues, we succeeded in improving the best laser resolu- tions from several million hertz to less than 1 thousand hertz." That work has continued up to today, producing some of the

basic patents used worldwide to make stable research lasers. Frequency-stabilized lasers made possible whole new areas

of research. At JILA, they have

been used for atomic spectros- copy at unprecedented levels of accuracy; to measure the relativ- ists dilation of time; in experi- ments on frequency and length standards that led the world's standards laboratories to change

their definition of the meter; in one of the first successful experiments to produce a sample of neutral atoms "cooled" to a

near-zero velocity (the other success was in another NBS

lab); and hundreds of other

applications.

Hall and his team continue to push at the limits of laser science. They are working with

Bell Laboratories and with Stanford University on delicate measurements of atomic reso- nant frequencies. The latter collaboration has produced, as a by-product, a new laser

stabilization technique.

One of Hall's most intriguing projects at the moment is a

collaboration with the University

of Texas on experiments to slip past the Heisenberg uncertainty

principle, which sets absolute

limits on the resolution at which

quantum systems can be ob- served. The method being used

is considerably different from the only successful experiment so

far, which was conducted at Bell Laboratories. Normally, explains Hall, you

cannot measure the strength of

an electromagnetic field such as a beam of light to better than

within one photon, no matter how fine your apparatus. Even a

field of zero—absolute darkcan only be measured to give-or-take a photon. Light, however, has two orthogonal

components, and the uncertainty

principle applies to the combination of the two components. In theory, says Hall, you can measure either component as

accurately as you wish, so long as you are willing to let the other component "run wild."

In practice, they are working on demonstrating a solid-state system in which, when the apparatus is turned on, the energy level of one component

of light actually declines from the

level measured in complete

darkness. "A darkness which is darker than nothing," says Hall. "There are applications in the

detection of gravity waves and a whole field of threshold signal detection. There'll be a lot of applications for a box that produces original darkness."
needed for the design of lasers, and applied the laser to a bewil- dering array of measurement tasks from catching speeding atoms in mid-flight to measuring the distance

to the moon. The accurate measurement of great distances is another J I LA

specialty. Dr. Peter Bender, who

calls himself a "theoretical experimentalist," is helping to improve the accuracy of distance measurements between radio astronomy centers in California, Massachusetts, and Sweden. At

present, they can do it to within about 3 centimeters. Bender hopes

to help improve that to 1 centimeter. The methodology is of great interest to geophysicists

studying plate tectonics. For several years, Bender has

been working with Hall and Dr. James Faller also of J I LA on long- range plans for an experiment

using the world's largest measure- ment instrument ever—a laser inter- ferometer using three satellites orbiting the Sun in a L-shaped

formation with arms 1 million kilometers long. The interferometer would search for evidence of gravitational waves—a theoretically

predicted but never observed

phenomenon.

On the terrestrial plane, Dr. Judah Levine, who works with both JILA and the NBS Time and Fre- quency Division, has applied clever timing techniques to long-term

experiments to measure minute

shifts in the Earth's crust. "This might ultimately apply to earth- quake prediction," explains Levine, "but that's in a very primitive state

right now; there's no agreement

even on what one should measure

to predict earthquakes. We're still at the stage of trying to understand

what's happening."

Levine's work at JILA has had

an unexpected payoff for NBS:

Some of the computer programs

he developed for geophysical

Dr. Gordon Dunn (right) of NBS and the Joint Institute for Laboratory

Astrophysics and Brett DePaola, a post-doctoral research associate, with

equipment used to study collisions of electrons and ions that occur in very

hot plasmas.

measurements are now being used

to maintain the NBS time scale, the

national reference for time.

"Concentration of

Excellence"

Perhaps the reason JILA works so

well is that it manages to merge the characters of its two sponsors into a single institution. The academic air of JILA and its close ties to the teaching program

blend in well with the University of Colorado. The last CU program

review panel cited JILA for the

quality of its research and its productivity (JILA scientists publish over 200 papers a year, and the

institute has graduated 130 Ph.D.

students to date) and noted "there are only a handful of places any- where that have a comparable

concentration of excellence in the areas of laser physics and atomic

and molecular physics."

Similarly, the institute's work at the frontiers of measurement tech- nology fits in well with the goals of

NBS. Speaking of the complex

array of research interests at JILA,

gravitational researcher Faller observes, "The pedal notes in this fugue are the precision measure- ment techniques—pushing how well you can do measurements to the

limits." There is an infectious energy

about the JILA laboratories; staff members tend to talk about the

"critical mass" of talents and

interests that make up the insti- tution. The general feeling is perhaps best summarized by Hall, "When you find one guy who's 52

years old coming in at night to do

research and another 62 coming in every morning at 7:30 to work in the labs, you know you've found an exciting place to work."

by Michael Baum

NBS Public Affairs Specialist
Safer, Quicker Ways to Prepare

Samples for Chemical Analysis

CEM Corporation chemist Lois B. Jassie places a carousel loaded with vessels into a research microwave oven. Specimens contained in the vessels will be dissolved and ready

for analysis within 10 minutes.

n an era when the word

"microwave" is tossed about

liberally in reference to anything from kitchen ovens to backyard

satellite dishes, microwave tech- ology is also finding a market in a more specialized setting: the chemistry laboratory. There oven-like microwave heat- ing devices are gradually replacing "hot plate" methods of dissolving

samples in acid for elemental

analysis at trace levels (parts per

million and lower). That's because

for certain sample types, microwave

technology is quick and contaminant-free, two factors essential to reliable chemical analyses. While microwave techniques offer sweeping improvements, there are

14

still some "bugs" to be worked out

to ensure their efficient operation

and safety. This is the goal of a joint research project between NBS and

the Indian Trail, N.C.-based CEM

Corporation, a maker of microwave

equipment for research purposes. The organizations are refining tech- niques for rapidly dissolving

samples—everything from biological

specimens such as human bone

and bovine livers to botanical, geological, metallic, and glassy

samples—in closed vessels within a microwave chamber. Many industries using microwave methods

have called NBS for help, and

some, investigating dissolution and

analysis procedures for materials such as nuclear waste and rock samples, have established long- term cooperative relationships with

NBS to better their understanding

of the technique.

Ultimately, NBS and CEM aim to provide interested labs with a

reliable procedure whereby chemists can select pre-determined

conditions under which a sample can be rapidly and totally dissolved. By combining the microwave

technique's ability to quickly heat

materials with the superior dis- solving properties of closed

containers under pressure, the NBS/CEM research team has de- vised a method of breaking down

samples that takes less than 1

0

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.

"Clearly one of the best advantages of using microwaves is the speed," says Dr. Howard M.

Kingston, an NBS chemist and

manager of the joint project. "This

is particularly important in the

laboratory of today simply because

the analytical instruments are now

so fast, you need a quick way to dissolve samples just to keep pace

with the analysis." At NBS, scientists use custom- made Teflon vessels with screw-on caps to contain the sample in nitric, hydrochloric, and other acids. Vessel caps are outfitted with valves to

relieve excess pressure, and the torque (tightness) of the caps is

strictly controlled. This type of container is used to minimize contamination of the sample. Glass

vessels, on the other hand, are not as contaminant-free. However,

because they are used widely in industry and can withstand higher

temperatures than Teflon, NBS and

CEM plan to include glass vessels

in their study.

Until the joint project began 2V2

years ago, there had been no

systematic research to give scientists ideas about just what to expect from microwave dissolution. Research ovens were available, and scattered experiments had

been done with them. But questions from industrial chemists

lingered: How can you know what

the temperature and pressure are

in the vessel? What are the vessels'

limitations? Can you ensure that microwave radiation is distributed equally? How can the vessels and

the oven be vented safely?

Working with an early model of the presently used research oven, Kingston and his colleague, Lois B. Jassie, a chemist for the CEM

Corporation, set out to answer

those questions.

And while the going was not always easy, Kingston and Jassie now have a workable system complete with a database of information

allowing industrial chemists to tailor their own microwave devices for desired results. Their success has prompted the

scientists to author technical papers about the microwave dis- solution technique, and they are assembling a textbook on the

subject to be published by the American Chemical Society.

Kingston and Jassie also are

taking advantage of well-attended gatherings of analytical chemists

to spread the word about their research. And the word is getting out. More than 200 companies, universities, and research laboratories have called NBS requesting help

with specific applications of microwave techniques.

Kingston and Jassie say they

welcome the calls, especially in light of the safety hazards which

could arise if the technique is used improperly. Says Jassie, "We have put a lot of emphasis on

safety in our research, because you can imagine that with factors such

...the NBS/CEM research

team has devised a method of breaking down

samples that takes less

than 10 minutes.

as temperature and pressure

involved, it is easy to get into trouble if you don't know exactly

what you are doing."

The two scientists typically advise chemists of container pressure limits and equipment configurations to prevent uncontrolled venting of superheated acids. And their method of predicting temperature from microwave power has elimi- nated the need to guess about

actual operating conditions. Though requests for quick advice

are common, some groups have

established more formal, longer term relationships with NBS to study microwave dissolution. Some

examples:

Los Alamos National Laboratory in New Mexico is investigating the effectiveness of microwaves in breaking down biological samples

such as buffalo and human bone

tissue. Scientists there have sought

help at NBS in researching the elemental composition of bone

tissue for anthropological studies of animal and human behavior.

Hints about the origins of early Earth crust are the goals of scientists at the Carnegie Institution of Washington, D.C., who are using

microwave techniques to prepare samples of rocks older than 2Vz

billion years for isotopic analysis.

E.I. du Pont de Nemours and

Company scientists plan to use

remotely controlled microwave

equipment to dissolve and analyze

radioactive sludge samples at the Defense Waste Processing Facility under construction at the Savannah

River Plant in Aiken, S.C. Du Pont

operates the plant for the Depart- ment of Energy.

Kingston and Jassie now are

fine-tuning the techniques even

further. For example, they are experimenting with a novel fiber- optic temperature-sensing system to monitor temperature more accurately and efficiently than the thermo- couples they have been using.

Also, they hope to improve the valve apparatus for the Teflon vessels and to test ways to automate the dissolution process. Companies, universities, or government agencies interested in learning more about the NBS/CEM

research should contact Dr. Howard M. Kingston or Lois B. Jassie, A353 Chemistry Building,

NBS, Gaithersburg, MD 20899,

301/921-3674,

by John Henkel NBS Public Affairs Specialist
Researchers Study the Process to

Improve Measurement Accuracy

hy quibble about an error of onehalf percent or traces of an impurity

present in concentrations as low as a few parts per billion? Isn't that nitpicking?

Hardly. And the chief of the NBS

Chemical Process Metrology

Division, Dr. Jaromir J. Ulbrecht, quickly illustrates how staggering

the costs of imprecision can be. "Vast quantities of oil and natural gas are moved through pipelines in this country," Ulbrecht explains.

"Every half percent error in measurement means thousands or

millions of dollars are lost." For

natural gas alone, metering inaccuracies may be responsible for about $700 million worth of gas

being unaccounted for each year in this country. Among the division's diverse clientele—chemical and related in- dustries that range from aeronautics

to utilities to winemaking—similar examples abound. For instance, Dr. James Whetstone, head of the

division's process sensing group,

refers to a measurement problem

that has been a "constant point of contention between gas suppliers

and semiconductor manufacturers." According to Whetstone, the manufacturers require high-purity gases to make microelectronic components, and suppliers of silanes and other gases aim to oblige their customers. Occasionally, however, water vapor, present

in minute but damaging concentrations, contaminates a newly

manufactured component. Did the

impurity originate in the gas? as manufacturers often maintain. Or, as gas suppliers are likely to suggest, was the water vapor pres- ent in the plant? Whetstone's group hopes to silence the argument by providing a standard method for measuring

the water-vapor content of gases. Next fall the process sensing group

will introduce a low-temperature

"frost point generator" that can produce water vapor in concentrations as low as 20 to 30 parts per

billion, according to Whetstone. An

outgrowth of this development, he

adds, are water-vapor concentration standards for high-purity gases, a boon to both semiconductor

manufacturers and gas suppliers.

In a way, the four groups in the Chemical Process Metrology Divi- sion serve as arbiters for private

companies and government agencies, including the Defense Depart- ment, Nuclear Regulatory

Commission, National Aeronautics and Space Administration, and

several others. As keeper and

developer of the national standards

for humidity, volume, liquid density,

fluid flow, and air speed, the divi- sion calibrates the reference instru- ments companies and government

agencies use to measure these

properties in the plant, laboratory, or field. When agents from the Bureau of Alcohol, Tobacco, and Firearms, for example, inspect a shipment from

the warehouse of an alcohol distiller, they use hydrometers that are

calibrated against the liquid density standards maintained by the NBS

process sensing group. The density

measurement, which determines

alcohol content, is the basis for calculating the federal excise tax on

shipments of spirits. "To continue to provide the best possible service, we've made major

efforts to upgrade our calibration

facilities and have introduced automation to improve efficiency

and to reduce uncertainties in calibration," Ulbrecht explains.

Back to Basics

Reducing uncertainties in measure- ment is also the objective of the basic research under way in the

division. Some of the studies will lead directly to new metering devices that can eliminate waste or improve efficiency, while providing

a better understanding of how

existing instruments work. Usually, there's more fundamental work to be done, however, like defining the

poorly understood behavior of gases and liquids upstream and

downstream from a meter in a

pipeline or identifying surface properties of materials now used in sensing devices. The underlying

reasoning is simple: If you under- stand the process better, you can

improve measurement accuracy,

"To continue to provide

the best possible service,

we've made major efforts

to upgrade our calibration

facilities and have introduced automation to improve efficiency and to

reduce uncertainties in calibration," Ulbrecht

explains.

perhaps by perfecting the old instrument or by devising new

approaches that, as Ulbrecht likes to say, yield "more robust

instrumentation." One candidate for improvement—solid-state sensing

devices—has come under the atom-by-atom scrutiny of researchers in the process

sensing group. These devices are

actually miniature resistors, but when they come in contact with

specific molecules, solid-state sensors adsorb some of the molecules and their resistance is changed in an electronic signaling

circuit. But for all their virtues, including

simplicity and durability, current devices are less than ideal. "Solidstate sensors for gas species are very nonspecific," Whetstone

explains. "Take tin oxide. At
Dr. Tsyh-Tyan Yeh is shown with the NBS laser Doppler velocimetry flow-metering research facility

which is being used to study flow-measuring devices.

elevated temperatures it absorbs an

awful lot of stuff. You may be

interested in the concentration of hydrogen atoms, but the sensor

can't tell the difference between

hydrogen and a hydrogencontaining gas like methane or hexane. So if you have a reaction stream that contains four or five constituents, you're fresh out of luck." The explanation for the metal's

indiscriminating ways lies on the

surface, those first few layers of tin and oxygen atoms that are ex- posed to the surrounding atmo- sphere and often are arranged

differently than the atoms that make

up the bulk of the material. Greatly

aided by two new facilities—one for

creating films that are only a few

angstroms (a few billionths of an

inch) thick and the other for detailed surface analysis, the process

sensing group has characterized surface adsorption properties of tin oxide. With this detailed information, the researchers can devise new

approaches to improve the sensitivity of tin oxide sensors. By strategically implanting

palladium, platinum, and other

catalysts on tin oxide surfaces, the researchers aim to build sensors

that have much greater specificity than the conventional material. Whetstone says it's unlikely that the new sensors will "see" only one

type of gas species, but they will be far more discriminating. The

key, he says, is to learn the basic

properties of catalyst-doped sensors, including their reactivity to

different gases, and then use them

in combination—as algorithmic or "smart" sensors. A model of the sensors' properties can be translated into a computer program. On the basis of sensor and temperature measurements, the program can be used to "deconvolute" the information, Whetstone says, and deduce concentrations of various gases in a

chemical reactor, for example.

"Whether the measurements can be made in real time will depend

on how fast the program is," Whetstone says. "It's a complex

modeling job. That's why we're

enlisting the help of the University

of Maryland's Center for Systems

17
Dr. Adolfas Gaigalas (standing) and John Houser review

test results of a nonintrusive metering system used to measure the solids in a pulp slurry pipeline.

Engineering to work on the modeling and computations."

Despite the complexity of the

task, Whetstone predicts that the

future in process sensing lies with the tandem of multiple sensors and

algorithmic programs. That's why

his group has mounted a parallel

effort for sensing concentrations of specific molecules in liquid streams, a development that would benefit food processors, biotechnology and

chemical-engineering firms, and a

host of other companies. Tailored sensors also interest the Nuclear

Regulatory Commission (NRC). The

NRC commissioned Dr. Ken

Kreider of the processing sensing

group to study the feasibility of using the devices as monitors of nuclear waste containment. Focusing on iridium oxide and

beginning with a detailed study of the metal's surface properties, the group plans to evaluate the possibility of using ion-specific sensors encapsulated in selectively per- meable polymer membranes.

Besides gams in specificity, such

sensors would offer much greater

durability than the glass-encased

sensors now used. "They won't break and go down the process

line," Whetstone says. Conceivably,

solid-state sensors could be placed

in food products as a check on

spoilage or processing conditions.

In contrast, glass devices can't be

used for this purpose because of the danger of breakage.

Longer Life for Sensors

and Meters

The importance of durability can't be underestimated, according to division chief Ulbrecht. "Many

meters must operate in harsh, corrosive environments, such as

slurries and effluent streams," he

says. "If a meter is sensitive to

slight changes caused by erosion, you've got problems. Once a meter has eroded, you can forget it. Your measurements will be inaccurate." The consequences of inaccur- acies are waste and inefficiency. "Chemical reactions take place in fixed proportions," Ulbrecht

explains. "If your measurements

of streams entering a continuous

flow reactor are off by a few

percent, you may not get the right chemical reaction or you may get only a fraction of the desired product." For paper manufacturers, errors

in measurement of the solids in a

pulp slurry pipeline, an especially corrosive environment, translate

into an inferior product. Currently, the standard meters used to measure the solids fraction are

inserted directly into the pipeline, where they inevitably break down.

Dr. Adolfas K. Gaigalas, head

of the multiphase reacting flows group, has come up with a novel technique to avoid this problem

and, in the process, improve the

quality of measurement. The

device he invented is protected from the corrosive effects of the

slurry and provides real-time measurement of the solids

fraction.

In a project funded by the Department of Energy's Office for Industrial Programs, Gaigalas devised a nonintrusive metering

system that exploits the properties
of radio waves. Flat, thin radio- wave antennas are built directly

into the inside wall of the slurry pipeline. Between the two antennas and also imbedded into the pipe

wall is a sophisticated detector that samples a radio wave-caused

electrical field at 32 separate points. According to Gaigalas, the final measurement—the determination of the slurry's solids content—is derived from a three-step procedure. First, one antenna fires, and

then the second. In the third step, both antennas fire simultaneously,

creating an interference pattern beneath the detector. At each step, the detector records the resulting

electromagnetic field and transmits the information to a computer that calculates the speed of the radio waves in the slurry. The calculations are compared with a mixing model,

and the comparison yields an accurate measurement of the solids

If you understand the pro- cess better, you can improve measurement

accuracy, perhaps by perfecting the old instrument

or by devising new

approaches...

content. The entire procedure takes about a minute, considerably faster than current methods. A prototype of the sophisticated meter already has been tested at the Institute for Paper Chemistry in Appleton, Wise. The next stepbuilding full-scale models for testing in actual paper mills—will soon follow. Meters are scheduled

to be tested in two plants, one owned by the Bowater Southern Paper Company and the other by

the Weyerhaeuser Company.

Gaigalas says he is grateful for the

industry's cooperation, but adds

that paper manufacturers have an

incentive. "They are eager to get a

meter that's accurate," he says.

"It's one thing to test a device in the controlled environment of the

laboratory and another to do it in a

manufacturing plant," Gaigalas

says. "I'm very optimistic, though. I think it will work, and I don't think

we'll encounter any problems."

Working Together

Another gauge of the widely shared

desire for accurate meters is the

participation of industry in two

consortia recently started by Dr. George E. Mattingly, head of the

fluid flow group. One consortium,

which is studying the measurement

problems that result when a meter

is installed too close to a pipe

"elbow" or valve, counts 10 firms as members, in addition to the Department of Energy. The other consortium has a roster that includes nine companies and

NASA, all of which are interested in improving the performance of vortex-shedding flow meters. These

devices, which are used in a wide

variety of situations, determine flow

rate by detecting the eddy-shaped

vortexes created by liquid flowing

through the meter. "Flow-measuring devices have

been around for decades, but there

still is a certain amount of mystery

about what really goes on when

fluid is flowing through a flow meter," Mattingly explains. "Our

goal is to combine the measure- ment expertise and fluid research

facilities at NBS with the industrial needs of consortia members."

Essential to the two groups'

efforts is the NBS laser Doppler

velocimetry (LDV) flow-metering research facility. This new facility will allow researchers to measure fluid conditions characteristic of those

confronted in the plants of partici- pating firms. Although research will be tailored to the problems of consortia members, Mattingly stresses that the emphasis will be on learning the

basic flow characteristics of liquids and gases. "This understanding is required to properly upgrade fluid- metering standards, which is the most practical way to achieve

accurate flow-rate measurements,"

he says. Lasers also play prominent roles

in the varied work of the Chemical

Process Metrology Division's largest

unit, the high-temperature reacting flows group. The group, headed by

Dr. Hratch G. Semerjian, has

demonstrated the analytical strength

and diversity of the combination of

lasers, fiber optics, and computers.

Just as certain aspects of the behavior of gases and liquids in pipelines are regarded as a "black

box," combustion processes pose

troubling unknowns that can't be

addressed with current analytical

techniques. The combustion of gases in industrial boilers, for example, is examined after the

fact, by analyzing emissions rising through the "smoke stack." The

optimal approach—one pursued

by Semerjian's group—would be

to monitor fuel-burning as it happens.

The optical diagnostic technique

the group has developed is akin

to the CAT (computerized axial tomography) scanning methods

used for diagnostic imaging in medicine. As in CAT scanning,

the group's tomographic method

produces computerized images

that are composites of many

projections, each taken from a

different angle. But instead of using x rays to create the richly detailed, three-dimensional images, the NBS researchers use

tunable lasers to generate a

wealth of information about the

light-absorbing and -scattering

properties of molecules and particles in the flame. As six laser beams scan the field, the atten- uated light from each beam is picked up by a photodetector and
then sent to a photoamplifier, which

intensifies the signatures. In the last leg of this relay of signals, the

photoamplifier transfers the spectroscopic data to a computer,

which processes information gathered from six different angles

and produces the composite

image. From the image, the creation of a complex computer program,

researchers can determine the temperature of the flame, the composition and concentration of the molecular components in a fuel, and the make up, concentration,

and movement of combustion

products. In all, the image provides a detailed and regularly updated

accounting of what happens during

combustion.

While this detailed information will aid efforts to improve fuel efficiency

and to control emissions, Ulbrecht foresees other applications for laser tomography. "A natural outgrowth,"

he says, is studies of "chemical vapor deposition," the process used to manufacture silicon wafers and fiber-optic materials. For all the technological marvels it underlies, the process, which can be used in different ways, is inefficient. Ulbrecht roughly estimates that silicon-chip manufacturers discard up to 60 percent of the chips they

make.

"Before you can control the process, you must understand the chemistry and the kinetics of the process," Ulbrecht says, adding

that laser tomography could subject

chemical vapor deposition to the

scientific scrutiny desired. The considerable powers of opti- cal diagnostics also are being

directed toward many other uses, including analysis of the incineration

of hazardous wastes, a problem

that is being studied by other groups as well. Burning of hazard- ous materials is a potential solution

to the dilemma posed by the growing accumulation of potentially toxic wastes at dump sites. But, as

Ulbrecht points out, incineration must be strictly controlled, which means that accurate measurements

are essential. Otherwise, the process might create new pollutants

that go undetected and are emitted

into the atmosphere, Ulbrecht

explains.

Looking to the Future

Biotechnology firms are among the intended beneficiaries of other ongoing research in the division. These firms are expected to become a major force in the chemical-processing industry. Says

NBS researcher Dr. Baldwin

Robertson, a member of the multiphase reacting flows group, "Bioprocessing is the chemical

"This understanding is required to properly

upgrade fluid -metering

standards, which is the

most practical way to

achieve accurate flow-rate

measurements."

engineering of the future," replacing the petroleum-based processes that have characterized

the industry for decades.

Bioprocessing, which exploits biochemical reactions, also presents

special measurement needs. Robertson is addressing one of these needs in his studies of the

destructive force created by stirring the nutrient-rich broth in a fermentation vat. While mixing is a common feature of chemical- manufacturing processes, it is especially critical in processes that use living cells. In the past,

trial-and-error approaches to find the optimal stirring rate for a

reaction were adequate, but these approaches won't do for biochemical reactions, Robertson explains.

"Vigorous stirring is necessary to get oxygen to the cells in the

broth," Robertson says, but too

intensive stirring can damage the

cells or limit their growth. With collaborators from the

University of Pierre and Marie Curie

in Paris, Robertson has devised an

electrochemical method for measuring the rate of "shear strain," the deformation that results when

liquid slides across a mixing blade. Robertson stresses that his work is at the basic research level, several steps removed from actual use in an industrial process. But the ability to measure a key variable in many

manufacturing processes, not just fermentation, strengthens the

scientific foundation from which

gains in efficiency and productivity

ultimately emerge.

While Robertson's work focuses on a factor that influences cell growth and survival in a fermentation vat, researchers in another group are developing a method

for monitoring the biochemical

reactions that take place in the

vat. The technique, called laser- induced fluorescence, produces a

wealth of data for determining the types of concentrations of inter- mediate compounds formed

during the biochemical reactions. (See the article on page 24.)

In cooperation with the Lehigh

University Center for Biotech- nology Research, the NBS re- searchers aim to unite their diagnostic system with computerized models, a combination that

will allow continuous surveillance

of the fermentation process.

In all of these projects, the

researchers' overriding goal is to help the chemical-processing

industry improve measurements,

and thus efficiency and economy,

by providing ever better measure- ment methods.

by Mark Bello Washington, D C-area Science

Writer
Expanded Version of IGES

Standard Available

he National Bureau of Standards

has released a new, extended

version of the popular Initial Graphics Exchange Specification

(IGES), a standard data format designed to simplify the exchange

of computer-generated design

information between otherwise incompatible computer-aided

design (CAD) systems.

The updated specification, Version 3.0, contains expanded

capabilities for representing part geometries, new capabilities to allow for creating standard

"libraries" of parts, and a new

method of reducing the size of IGES files. The new version also includes many clarifications and

refinements to the IGES standard based on experience with using an

earlier version of IGES across a wide variety of CAD systems.

The original IGES was developed

in 1979 under sponsorship of the

Version 3.0 contains ex- panded capabilities for

representing part geometries, new capabilities to

allow for creating standard "libraries" of parts,

and a new method of re- ducing the size of IGES

files.

Air Force Integrated ComputerAided Manufacturing Program. The

specification defines a computer file format for the storage of three- dimensional geometric information and two-dimensional drawing

information that is created by CAD

systems. Data can be exchanged between

two otherwise incompatible CAD

systems by using pre- and post- processors to translate the data out

of the first CAD system into the IGES format, and out of the IGES

format into the second system.

Department of Defense and

National Aeronautics and Space

Administration procurement specifications routinely require the use of IGES, and IGES translators are

available as options from every major U.S. CAD-system

manufacturer. IGES is managed by a joint industry-government group coordi- nated by NBS. The first version of IGES was adopted by the American National Standards

Institute (ANSI) as a major portion

of its standard Y14.26M. Version

3.0 was submitted to ANSI in March 1986.

In addition to clarifying several aspects of earlier versions of the standards, IGES Version 3 adds new capabilities in geometry for offset curves, offset surfaces, and

curves on a parametric surface. A

trimmed surface entity allows for the

definition of surface boundaries,

and new capabilities in annotation have been added.

IGES 3 introduces greatly en- hanced capability for user-defined MACROS essential for creating standard part libraries of symbols

and components.

IGES 3 also introduces a method

of reducing IGES files to one-third

of their previous size, using a compressed ASCII format, to save on storage space and telecommunications costs. While continuing "to upgrade and

improve the graphics exchange

standard, the IGES organization

has also begun work on a Product Data Exchange Specification

(PDES), which will allow a complete

product model database to be

exchanged and used directly by

IGES is a standard data

format designed to simplify the exchange of

computer-generated

design information

between otherwise incompatible CAD systems.

advanced computer-integrated

manufacturing programs such as automatic process-planning or inspection systems.

Information such as manufacturing features, tolerance specifications, material properties, and

surface finish specifications will be

made available to application programs in the PDES format. IGES technical meetings are held

regularly throughout the year to discuss enhancements and modifi- cations to the IGES standard. The

next meeting is scheduled for the week of October 20, 1986, in Huntsville, Ala. Interested persons

are invited to contact Gaylen

Rinaudot, IGES coordinator, A353

Metrology Building, NBS,

Gaithersburg, MD, 20899, 301/921- 3691. The Initial Graphics Exchange

Specification (IGES), Version 3.0 (NBSIR 86-3359) is available for $40.95, prepaid, through the

National Technical Information

Service, Springfield, VA 22161. Order by PB #86-199759. Microfiche copies also are available. M.B.

21
NBS Studying New Technique to

Identify Irradiated Foods

esearchers at the National Bureau

of Standards are experimenting

with an extremely sensitive

analytical procedure that may make

it possible to determine whether or not a sample of meat has received

radiation processing to sterilize it or

to inhibit decay.

At present, no reliable test method exists for determining whether or not a foodstuff, other than dried spices, has been treated

with ionizing radiation. The technique may be adaptable

to vegetable matter and seafood as

well as meats, according to Drs. Michael Simic, Miral Dizdaroglu,

and Lisa Karam of the NBS Center

for Radiation Research. In addition,

efforts are under way, in collaboration with the NBS Center for Analytical Chemistry, to develop a scale

to determine how much radiation was administered to the foodstuff. Radiation processing of foods,

especially meats, is a comparatively new procedure in the United

States, although it is practiced

widely in some other countries. Doses of ionizing radiation—either x rays or electron beams produced

by machines, or gamma rays pro- duced by radioactive sub- stances—can extend the shelf life of

fruits, vegetables, and meats by

retarding spoilage. At sufficiently high levels, radiation will either kill harmful bacteria or insects in the food or inhibit their reproduction. Fresh meat, for example, can be

sterilized and stored in air-tight packages at room temperature for months or years. The food itself does not become radioactive.

In the 1960's, the Food and

Drug Administration (FDA), which

regulates food irradiation, approved

the use of radiation for treating

potatoes and wheat, although the process is not used commercially in the United States. In 1983, the irra- diation of spices to kill insects was

approved. In the past year, final approval was granted for low-level

irradiation of pork to kill trichinae worms and of fruits and vegetables

to extend shelf life. The total dose of radiation given

to foods must be carefully controlled. A dose that is too low fails to produce the desired effect, while a dose that is too high may damage the food. In addition, the FDA

sets maximum exposure limits for the lifetime of the food product. In the case of pork, for example, the

Experiments at NBS

demonstrate that the

amount of orthotyrosine

in the fiber of chicken

meat increases in direct

proportion to the amount

of radiation the meat has

received.

limit is 100 kilorads. (While just 1 kilorad is sufficient to kill a healthy, adult human, less complicated

organisms like insects are hardier.) These limits present a problem

for regulators and food importers,

who may need to determine whether a given shipment has ever been irradiated, and if so, to what

extent. "What you are looking for is a

reliable, built-in 'dosimeter' in foods," explains Simic, the NBS

project chief. "For example, the Germans have developed a method, based on fluorescence, to tell whether or not spices have been

irradiated. It has two problems,

though. The spices have to be dry, very dry, and the test can't be

repeated—the effect fades after the

first time." The NBS effort at first concentrated on finding so-called "unique

radiolytic products"—chemicals

produced by the effects of radiation

that would not be present in unirra- diated food. The amounts of such

chemicals produced by radiation processing would be very small— perhaps a few micrograms

in every gram—but ideally the

amount present should increase in direct proportion to the radiation dose received, a built-in dosimeter. The researchers used a special- ized analytic technique—gas

chromatography/mass spectrometry

with selected ion monitoring—in their search for a useful "dosi- meter" chemical.

"This is a very sensitive tech- nique. You can detect quantities as

small as a few picograms (1 picogram = 0.000000000001 gram)"

says Dizdaroglu, "but you have to know what you're looking for. We

studied the radiation chemistry of peptides and proteins in model

systems and made chemical ki- netics measurements to determine what the likely reactions were, and

what the products would be." An early candidate was the amino acid ortho-tyrosine, which is produced by the addition of a

hydroxyl (hydrogen-oxygen)

radical to another amino acid, phenylalanine. Hydroxyl radicals are formed by the break-up of water molecules under ionizing

radiation. Ortho-tyrosine is a

chemical isomer of a naturally occurring amino acid, paratyrosine (that is, both have the same chemical formula, but they

differ in the location of the hydroxyl group.)

The researchers ran into a snag when they discovered that unirradiated control samples of chicken meat also contained minute traces of ortho-tyrosine.

"Apparently." says Simic. "the enzyme in the body that is supposed to make para-tyrosme

out of phenylalanine occasionally

makes a mistake." The concentration was so low

that it had escaped the notice of food researchers, but it was high

enough to interfere with the delicate

test procedure the NBS team was

trying to develop.

A suggestion from a colleague at the Department of Agriculture led to the solution. "The idea is that
amino acids are not necessarily

used at the same place where

they're made," according to NESS' Karam. "Meat has two basic components, fiber and everything

else—a kind of watery fluid. Tyrosine is made from phenylalanine in the fluid, and then the body takes it and attaches it to the

fiber. Ortho-tyrosine can be made

by mistake sometimes, but the body appears to recognize it as a

mistake and won't use it in the

fiber." The answer, then, was to carefully wash meat specimens in water

to remove everything but the fiber. Any ortho-tyrosine found in the washed sample could only come

from the radiation-induced trans- formation of phenylalanine already

present in the fiber. Experiments at NBS demonstrate

that the amount of ortho-tyrosine in the fiber of chicken meat increases

in direct proportion to the amount

of radiation the meat has received. The concentrations are at the level of a few parts per million. Unirra- diated control samples show no

ortho-tyrosine in the fibrous tissue at the current limits of detection. "The great thing," notes Simic,

"is that we are not talking about some chemical that is created

uniquely in food that has been

irradiated. Ortho-tyrosine occurs

naturally in quantities much greater than are created by radiation processing, and yet in the meat

fiber it is apparently produced only

by irradiation, so you can use it as

a natural dosimeter." NBS is continuing to study this new technique with the goal of developing an analytical method for determining irradiation-dose levels

in meats. The Bureau will also in- vestigate its applicability to other

foods. The U.S. Department of Agriculture is supporting the appli- cation of this basic research to the measurement of radiation dose in poultry and pork. Technical advice

is also being provided by the Food

and Drug Administration. M.B.

Dr. Miral Dizdaroglu (left) of the NBS Center for Radiation Research and Dr. Michael Welch of the Center for Analytical Chemistry prepare to inject a sample of meat fiber into a combined gas chromatograph/mass spectrum

analyzer. Sensitive analytical procedures developed at NBS may soon make

it possible to determine whether or not common foods have ever received

doses of radiation—and if so, how much.

23
NBS Research in Biotechnology:

Providing the Scientific Fundamentals

he harnessing of bacteria to generate insulin and the capture of enzymes to speed fermentation of soy sauce are just two feats of biotechnology—a growing field whose products are expected to gross over $50 billion by the year 2000. The potential of biotech- nology research is great: a cleaner environment, improved diagnosis

and treatment of diseases, better food crops, and alternative energy

sources. But like most fledgling

industries, biotechnology is in need

of standards and firm scientific fundamentals to assure better control and efficiency of its commercial

processes. As it has for many other new

industries—from cast iron foundries

in the early 1900's to the semi- conductor manufacturers of today—the National Bureau of Stan- dards plans to help the biotech- nology industry by providing

essential measurement methods,

standard data and materials, and

scientific fundamentals. For example, researchers at the NBS

Center for Analytical Chemistry

(CAC) are refining innovative

analytical techniques so that minute,

yet potentially harmful, impurities in protein biotechnology products

such as insulin or growth hormones

can be detected. They are also developing state-of-the-art bio- sensors that can speed the clinical diagnoses of various disorders and

aid the manufacture of genetically

engineered microbial products. Other researchers within the Bureau's Center for Chemical

Engineering (CCE) are working to improve the efficiency of biochemical reactors as well as develop

techniques for separating biochemical products from solutions. At the same time, investigators at the NBS

Center for Chemical Physics (CCP)

are uncovering the detailed struc- ture and functional relationships of enzymes that are frequently used to generate biochemical products.

CCP researchers also are identify- ing how various factors such as

temperature and pH influence the

functioning of enzymes. In addition, NBS has joined the University of Maryland and Montgomery County,

Md.. in establishing a Center for Advanced Research in Biotech- nology. (See page 6.) "Biotechnology is a whole differ- ent ball game compared to the tech- nologies most industries are used

to," says NBS biochemist Dr. Ann

Plant. "We don't have a lot of the basic science at our disposal that

will enable us to take microbes, enzymes, and so forth out of bio- logical systems and apply them

immediately in an industrial setting." A major challenge facing biotech- nology companies is scaling up the

laboratory production of genetically

engineered microbes to generate

commercially feasible quantities of products. To accomplish this effectively, manufacturers must be able

to monitor quickly and precisely a number of environmental factors, such as nutrient levels, and the concentrations of desired and

waste products within reactors so

The advantage of this

biosensor... is that it is quick and requires a minimum of equipment

and expense.

adjustments to improve quality and

productivity can be made quickly. Plant and her coworkers are de- veloping a biosensor that recognizes specific organic molecules and uses them to produce measurable electrical signals. The bio- sensor employs the body's own

natural detectors—antibodies—

whose chemical arms latch onto

specific compounds called antigens

within their midst. Plant and her col- leagues have taken these antibody

arms, attached them to beads, and

added a solution of lipid vesicles

(similar to water-filled balloons) containing electrochemical or fluo- rescent markers. The vesicles have on their surfaces the antigens of the

compound of interest— insulin, for example—and consequently bind

to the antibodies on the beads. Then when a solution containing

insulin is added, the insulin molecules displace the vesicles which return into solution and are

collected. When detergent is added

to the solution containing the

vesicles, they explode, releasing the electrochemical or fluorescent markers. This allows the number

of insulin molecules displacing the

lipid vesicles to be determined. The advantage of this biosensor over other techniques currently

used to measure small quantities of biological compounds is that it is quick and requires a minimum of equipment and expense. Using

this system it is possible to do an

analysis for a compound in only

1 0 minutes whereas an analysis

for the same compound using

other standard techniques such as radioimmunoassay could take hours or even days.

Besides being used as a monitor in biochemical reactors, Plant also expects this biosensor system

to be useful in a clinical setting. The sensor can monitor the blood

levels of drugs such as digoxm,

for example, that can be lethal at levels only a small fraction above

the levels at which they are

effective. "The system could be

set up in a physician's office and

the tests could be performed

while the patient waits," Plant says. NBS scientist Dr. Hratch Semerjian is also working on

monitoring techniques for bio- chemical reactors. He hopes to fingerprint the identity and quantity

of compounds within a reactor by

shining a laser beam into the

reactor and noting how much light

is absorbed and the pattern of wavelengths of light reemitted. Each compound will reemit light in a distinctive wavelength pattern, Semerjian explains, and the quantity of light emitted will indicate a
By using laser-induced fluorescence, Dr. John Horvath (left) and Dr. Hratch Semerjian hope to be able to

identify and quantify compounds in biochemical reactors.

compound's concentration. Al- though this technique, called laser- induced fluorescence, has been

used for decades to detect simple

molecules, researchers have not yet shown that the method works for the large and complex molecules

that play key roles in biochemical

reactors. The main advantages of using

laser-based measurements to monitor bioreactors are that measure- ments can be made in minutes,

and there is no danger of contaminating the reactor while

removing test samples because the

laser beam can be directed through a window or optical fiber

into the reactor. A laser system will also be cost effective and extremely

sensitive to small concentrations of substances, Semerjian says. Such

sensitivity is crucial for detecting

unwanted by-products in reactors before their concentrations reach damaging levels. "Effective monitoring of reactors

is vital to the commercial application of biotechnology," Semerjian

says. "Without it production may be

inefficient, which would render

products economically

unattractive." Semerjian has tested a laser- induced fluorescence system and

shown that it can discriminate among three amino acids, the

building blocks of proteins, at very low concentrations. He plans to test the feasibility of using the system to detect larger molecules closer in size to proteins.

But, even if reactors generate

biological products efficiently, there

is the additional problem of separating the product from the
Particulates Phase 1 Phase 2 Phase 1 (e.g., cell debris) (PEG) (Dextran)

Fermentation Separation Separation

Schematic of the two-phase aqueous extraction technique being evaluated for its efficiency in separating

proteins.

cellular debris and by-products in the reactor solution. The desired end product frequently only comprises 1 percent or less of the total solution because higher concentrations are lethal to the micro- organisms generating the product.

"Separating a product out of 99

percent water and other impurities

is a chemical engineer's night- mare," says NBS chemical

engineer Dr. Subhas Sikdar. "Conventional separation techniques

such as distillation or filtration cannot separate a product with such a low concentration." NBS researchers at the Bureau's

Boulder, Colo., laboratories are

trying to develop innovative techniques to separate biomolecules from solutions at low concentrations. Much of their effort has focused on an elegant technique

known as "two-phase aqueous

extraction," which relies on a

curious phenomenon. Certain combinations of polymers, when

dissolved in water in the proper

concentrations, create solutions which will not mix with each other even through both are in aqueous

solution—a "two-phase solution." One phase is "hydrophilic," the

other, "hydrophobic." (The

difference has to do with the arrangement of electric charge in the molecules.) If you add a

26

solution of proteins to this, give the mixture a good shake, and wait for the two phases to separate again, the more hydrophilic proteins will migrate to the hydrophilic half of the solution, and the more

hydrophobic proteins will move to the hydrophobic half, providing a

protein-protein separation which

would otherwise be very difficult to do.

Initial tests indicate such a system can efficiently separate two different types of proteins from each other, and NBS researchers plan to assess the efficiency of two-phase

aqueous extraction in separating more complex combinations of compounds. They also are deter- mining the various conditions that

affect the efficiency of the separation process. "The advantages of two-phase

aqueous extraction are that it can be done at room temperature,

which makes it energy efficient; it can be done on a large scale; and proteins are not likely to lose

their natural configuration or shape during the process," Sikdar

says.

In addition, Sikdar is testing the

possibility of using an artificial membrane to separate amino

acids, common biotechnology

products. The membrane, made

primarily of Teflon, is armed with a charge that allows only amino

acids to pass through. Also, by

altering the acidity of the solution, the membrane can be used to

separate basic amino acids from

acidic amino acids. The separation can be done at room

temperature and pressure so it is energy efficient, Sikdar says. Sikdar and his colleagues are

also measuring the speed at which various proteins travel through aqueous solutions and

the solution properties that distort the shape of proteins.

Once the final biotechnology

product is generated and separated, its purity must be assured

in order for it to be sold. Dr. Dennis

Reeder, NBS chemist, and his coworkers hope to aid biotech- nology companies in assessing the

purity of their products by improving the accuracy of a technique

called two-dimensional electro- phoresis, which is used to separate

and help identify proteins. With this technique, naturally charged proteins in solution are

Such information is invaluable to biotechnology companies at- tempting to tailor-make

enzymes that will carry

out specific reactions.

separated by their charges when

they are passed through a gel column that has a positive elec- trode on one end and a negative

electrode on the other forming a pH gradient or a range of acidic to basic environments. The gel containing bands of the separated

proteins is then put onto a second

gel column that separates the

proteins by molecular weight. Because proteins weighing as

little as a trillionth of a gram can be

detected via two-dimensional

electrophoresis, the technique can

be used to assess the purity of a
protein product by visualizing

protein contaminants. But two- dimensional electrophoresis is a

relatively new technique in need of refinement, according to Reeder.

' Two-dimensional electrophoresis

is moving from being an art to becoming a science," he says. "There is a great deal of variability between laboratories using this technique."

A number of factors, such as

electrode distance, the composition

and shelf life of the reagents used,

and the temperature at which the procedure was done, can affect the accuracy of the end results, Reeder

explains. To counter that variability, Reeder and his colleagues are working on standard methods and

reagents for two-dimensional

electrophoresis. Other investigators

in his group are assessing the

factors that affect the protein

binding of silver stains used to detect and quantify proteins in electrophoretic gels. In addition, they are developing methods for immobilizing and stabilizing enzymes and proteins.

Reeder is aiding other NBS bio- technology researchers by

assessing the stability and purity of the reagents used in their research. The precise measurements made

by the NBS Chemical Thermodynamics Division, for example, are

only accurate if the compounds

they are testing are pure. Investi- gators within this division are determining how biomolecules react under different temperatures, pH,

and electrolyte concentrations.

Detailed knowledge of such

thermodynamic properties is important for optimizing commercial

biotechnology processes. One important industrial bio- chemical reaction—the conversion

of glucose to fructose—has been

studied by NBS chemist Dr. Robert Goldberg and his coworkers. Using

a specially designed microcalor

imeter and high-performance liquid

Dr. Dennis Reeder is working to improve the accuracy of two-dimensional

electrophoresis so that biotechnology companies can use the technique

to assess their products' purity.

chromatography, they measured

the amount of heat released and

the equilibrium ratio of glucose, a

relatively cheap sugar, to fructose, a sweeter sugar widely used in food processing, as the temperature varies. From these data, Goldberg and his coworkers were

able to predict reliably how the ratio of glucose to fructose varies with temperature outside the range of measurement—information critical to optimizing the conversion process, which is carried out by an enzyme.

This information also allows manufacturers to decide whether it is economically practical to develop

enzymes that will work at higher

temperatures. Because some of the most

important tools and products of bio- technology are enzymes, NBS

physicist Dr. Alexander Wlodawer is

trying to use the fine details of various enzyme structures as keys

to unlocking how the compounds

work. Such information is invaluable

to biotechnology companies

attempting to tailor-make enzymes

that will carry out specific reactions. To obtain the maximum amount

of structural information, Wlodawer

uses the techniques of x-ray and

neutron diffraction, aiming a beam

of either x rays or neutrons at a

crystallized form of the biomolecule

under study. The beam is scattered

at different angles and with

different intensities depending on

the type of atoms it hits and their geometric arrangement. Detectors record the scattering pattern and

a computer model is used to

27
reconstruct the atomic positions in the molecule. Because enzymes and other

biological materials may contain as many as 10 million individual atoms, it has only been recently

that researchers have even

attempted to map the detailed chemical structure of biomolecules. Wlodawer and his coworkers completed the first highly refined description of the

structure of ribonuclease, an enzyme used in digestion of nucleic acids. They described the atomic positions within the molecule to within .01 to .02 nanometer—the critical size scale

or resolution needed to study the motions of individual atoms at the enzyme's active site where

reactions take place.

Wlodawer accomplished this feat by combining results from neutron

diffraction with x-ray diffraction. Neutrons are more strongly scattered by hydrogen, making

neutron diffraction an excellent method for determining the position

of hydrogen atoms in a molecule.

X-ray diffraction, on the other hand,

depends on the fact that x rays are

scattered more strongly by heavier atoms such as metals than by

lighter atoms like hydrogen. The

two techniques, then, provide

complementary information about

the type and geometric placement

of atoms in a molecule. Wlodawer is using ribonuclease and other proteins as model

systems to devise generic measure- ment methods that can be applied

by other researchers to study the

structure of biomolecules.

Ultimately, he also hopes to un- cover the connection between

structure and function so that enzymes can be designed to carry out desired reactions efficiently. NBS quantum chemist Dr. Walter Stevens has similar objectives, but uses different methods. Instead of neutrons and x rays, Stevens' main

Using several techniques, including x-ray diffraction, Dr. Alexander Wlodawer studies enzyme structures to learn

more about how they work.

tools are equations and high-speed

computers. Stevens tries to under- stand chemical interactions at their most fundamental level by describing the energy states of the molecules involved. Stevens and

his colleagues, explains Dr. Pierre Ausloos, director of the NBS Center

for Chemical Physics, are theoreticians who use equations to predict

Investigators... are determining how biomolecules

react under different temperatures, pH, and

electrolyte concentrations.

the outcome of chemical reactions. These equations mathematically

model the behavior and energy

states of individual atoms and

molecules. Equations used to describe even the simplest bonding

patterns between two atoms are so complex that high-speed computers

are needed to carry out the

calculations. Biotechnology is a relatively new

application for quantum chemistry,

according to Stevens, because of the large size of biomolecules. Rather than take on whole molecules at once, quantum chemists

study individual molecular frag- ments that make up the whole. NBS researchers are calculating the

strength of chemical bonds

between active sites of enzymes

and particular molecules, for example. A small change in the atomic composition of the active

site could either speed up the

reaction or prevent it from happening at all. By helping to understand the effects of subtle changes in either the active site of an enzyme or in the molecule it is reacting with. Stevens and his col- leagues can often minimize the time and expense needed for actual laboratory experimentation.

In the future, they want to investi- gate larger molecular groups using molecular mechanics and reaction

field techniques. By approximating
Using experimental data and sophisticated computers, Dr. Irene Weber maps the detailed

chemical structure of biomolecules to determine how they can be tailor-made to carry

out specific reactions.

some information which is dealt

with explicitly in quantum mechanics, molecular mechanics is capable of describing the energy

levels and bonding patterns of much larger molecular groups. While quantum mechanics is limited to a few dozen atoms at a time, molecular mechanics can be used

to study groups containing

hundreds of atoms, but at a lower

level of accuracy. "What we really need is a way to combine the quantum mechanics

with less accurate methods so that the important active sites of the biomolecules can be studied in a

realistic molecular environment

rather than as simple fragments," says Stevens. To make their cal- culations more realistic, these

researchers are developing a new

theoretical tool called the "reaction

field" method. In this method, the quantum mechanical equations describing the active site are modified

to account for the influence of the remaining parts of the molecule. The non-active parts of the molecule provide a "reaction field" in which the chemistry at the active

sites takes place. By including the

reaction field in a study of the

active site, molecules containing up

to 1 ,000 atoms may be studied

theoretically. The group uses a computer to do these large calculations and to produce three-dimensional displays

of biomolecules and processes under study. Three-dimensional

graphic displays of molecules,

explains Stevens, are helpful in

visualizing how the structure of a

molecule is related to its function and in collaborative studies with experimentalists like Wlodawer.

The combined efforts of the researchers at NBS should help

the burgeoning biotechnology

industry use nature to its advantage in generating commercially useful products. "It's exciting to work in this area," says

Semerjian, "because our work can have such a large impact on

a wide range of fields from fuel to vaccine production."

by Margie Patlak Milwaukee, Wisconsin-based

Science Writer

29
NEW PUBLICATIONS

DIRECTORY OF FEDERAL

CERTIFICATION PROGRAMS FOR

PRODUCTS AND SERVICES

Toth, R.B., Federal Government Certifica- tion Programs for Products and Services, Natl. Bur. Stand. (U.S.), NBS Spec.

Pub. 714, 157 pages (April 1986). Order by

stock no. 003-003-02719-7 from GPO, $8

prepaid.

The federal government's certification programs cover a wide variety of goods

and services including manufactured

products, agricultural commodities, medical

devices and drugs, and defense procure- ment. This directory, which can be used by

manufacturers, distributors, state and local government officials, consumers, and

others concerned with the standards and

procedures used in federal certification programs, contains information on 61 of these programs. Each entry describes the scope and nature of the program, the

testing and inspection practices, standards

used, methods of identification and enforce- ment, reciprocal recognition or acceptance

of certification, as well as other relevant

information. This publication is the second of a threepart series which includes a directory of private sector product certification pro- grams (NBS Spec. Pub. 703) and a companion volume on state programs now

being compiled to complete the series. For more information on the certification programs, standards, and standards-related

subjects, contact: Standards Code and

Information, Office of Product Standards

Policy, A629 Administration Building, NBS,

Gaithersburg, MD 20899, 301/921-2092.

'if)

FUNDAMENTAL INTERACTIONS WITH

COLD NEUTRONS

Greene, G.L., The Investigation of Fundamental Interactions with Cold

Neutrons, Natl. Bur. Stand. (U.S.), NBS

Spec. Pub. 711, 1 63 pages (February

1986). Order by stock no. 003-003-02718-9

from GPO, $8.50 prepaid.

NBS has published the proceedings of a November 1985 workshop on the use of cold (slow) neutrons to study the properties

of fundamental interactions of particles. More than 50 researchers from 23 institu- tions in North America and Europe

attended to review current research and to propose future work. The results are important to fields such as the theory of the weak interaction, nuclear theory, astro- physics, and theories of invariance laws and symmetry principles. The workshop was sponsored by NBS and the Depart- ment of Energy to gather information for use in planning research efforts at the cold- neutron source now being developed at the NBS research reactor.

FEDERAL STANDARD FOR ADA

Ada, Natl. Bur. Stand. (U.S.), FIPS PUB

119 (November 1985). Order by title and

FIPS PUB 119 from NTIS, $23 prepaid

(includes the American National Standards

Institute specifications document).

A federal standard for the computer program language Ada is now available and has been approved for federal govern- ment use by Commerce Secretary Malcolm

Baldrige. Ada is a high-level language

suitable for use in programming appli- cations such as control of real-time processes or parallel processing; very large

systems where correct modularization is crucial; systems which need to be very

reliable; and systems which are to be

developed with reusable software packages. The Federal Information Processing

Standard, which became effective May 1

,

1986, adopts a voluntary industry standard

issued by the American National Standards

Institute. A transition period beginning on

the effective date and continuing 1 year will provide time for industry to produce Ada

processors conforming to the standard.

TECHNICAL ACTIVITIES OF THE

CENTER FOR CHEMICAL

ENGINEERING

Hord, J., editor, Center for Chemical

Engineering Technical Activities: Fiscal Year 1985, Natl. Bur. Stand. (U.S.), NBSIR

85-3039, 160 pages (February 1986). Order by stock no. PB 86-166295 from NTIS, $16.95 prepaid.

The NBS Center for Chemical Engineering focuses its research on support of the chemical and related industries, including the chemical, petrochemical, petroleum,

gas, paper, biochemical, energy, and

food and drug sectors. It provides the fundamental scientific framework for reliable measurement and databases that assures equity in domestic and inter- national trade and enables improved

innovation, design, and control of chemical processes. Descriptive summaries of the research projects, including objectives, progress, publications, and staff are included in this report.

PROCEEDINGS FROM ACCESS TO

JAPANESE LITERATURE SEMINAR

Brady, E.L., editor, U.S. Access to Japanese Technical Literature: Elec- tronics and Electrical Engineering, Natl. Bur. Stand. (U.S.), NBS Spec. Pub. 710, 155 pages (January 1986). Order by stock

no. 003-003-02709-0 from GPO, $6 prepaid.

How can the United States gain better access to Japanese technical literature in electronics and electrical engineering? A

June 1985 seminar held at NBS focused on this question and the resulting publi- cation offers transcripts of presentations by

representatives from Congress, industry,

universities, and federal agencies. The common thread in the presentations was

interest in maintaining current knowledge of technical progress in Japan despite

frustration over language barriers. Few

Americans can read Japanese and only about 20 percent of Japanese technical

literature is routinely published in English. This raises questions such as: How important is the 20 percent available in English?

How can one gain access to the other 80

percent? The seminar offered possible answers, including a more active translation

role for professional societies as well as support from American industry.
REVISED INDEX OF U.S. VOLUNTARY

ENGINEERING STANDARDS

National Center for Standards and

Certification Information Staff, Key-Word-lnContext (KWIC) Index of U.S. Voluntary

Engineering Standards, Natl. Bur. Stand.

(U.S.) (January 1986). Order microfiche copies only by title and stock no. PB 86- 154408 from NTIS, $13.50 prepaid.

Manufacturers, exporters and importers,

and others concerned with standards developed by U.S. trade associations and

technical and professional societies will be

interested in the revision of this index. It contains more than 28,000 titles of stan- dards, specifications, test methods, and

recommended practices published by 422

U.S. standards-developing organizations.

First published in 1971, the revised microfiche index provides the title, date, source, and number of the standard for each entry. Titles can be found by all of the

significant keywords they contain. For

information on the KWIC index, contact the Standards Code and Information Office, A629 Administration Building, NBS,

Gaithersburg, MD 20899, 301/921-2092.

PROPER USE OF PASSWORDS FOR

COMPUTER SECURITY

Password Usage, Natl. Bur. Stand. (U.S.), FIPS PUB 112,56 pages (May 1985). Order by title and FIPS PUB 112 from

NTIS, $9.95 prepaid.

Passwords have been used for centuries as a way to prove one's right to access or

information. Today, they commonly are used to deter unauthorized access to computer systems and networks. While they are

not the only method of authentication, nor

necessarily the best, if properly used,

passwords can provide reasonable deter- rence. Federal Information Processing Standard (FIPS) Publication 112 describes

basic security criteria for using passwords

in computer systems. (FIPS are published

by NBS for use by the federal government.) The standard discusses 1 0 factors to be considered in establishing password

systems: composition, length, lifetime, source, ownership, distribution, storage,

entry, transmission, and authentication

period. Approved last year and recently

issued, the standard took effect June 1

,

1986.

ANNUAL DIRECTORY FOR NVLAP

LABORATORIES

Berger, H.W., editor, 1985-86 NVLAP

Directory of Accredited Laboratories,

Natl. Bur. Stand. (U.S.), NBSIR 86-3315,

117 pages (January 1986). Order by stock

no. PB 86-158003 from NTIS, $16.95

prepaid.

NBS has published the annual directory for the National Voluntary Laboratory

Accreditation Program (NVLAP), which is administered by the Bureau. The directory

provides indexes to more than 140 laboratories nationwide that are accredited in one

or more areas of testing. The indexes

include a list of laboratories by name and

NVLAP code number, test methods,

accreditation program, and geographical

location of each laboratory. There are

laboratory accreditation programs for thermal insulation; ready-mixed field concrete; carpets; solid-fuel room heaters; acoustical testing services; processors of personal radiation dosimeters; and

commercial products (paper and paper

products, paints and related coatings and

materials, and mattresses). Laboratories

that test photographic film, seals and

sealants, and electromagnetic and tele- communications equipment are also included.

EVALUATION OF HEAT DETECTORS

BY COMPUTER PROGRAM

Stroup, D.W., Evans, D.D., and Martin, P., Evaluating Thermal Fire Detection

Systems [English Units], Natl. Bur. Stand. (U.S.), NBS Spec. Pub. 712, 557

pages (April 1986). Order by stock no. 003-003-02727-8 from GPO, $25 prepaid.

Researchers in the NBS Center for Fire Research have developed a computer program to evaluate heat detection systems

installed in existing buildings. Depending

on ceiling height, spacing of detectors, type

of detector, and how fast the fire grows,

the program will determine how long it will take for the detector to be activated. The

user-friendly program is available in both BASIC and FORTRAN and will run on

mainframes as well as personal computers.

In addition, the FORTRAN version was

used to generate an extensive set of tables (included) which can be used to quickly evaluate response time of common

systems.

1985 ANALYTICAL CHEMISTRY

ACTIVITIES REPORT

Durst, R.A., Hertz, H.S., and Taylor, J.K., editors, Technical Activities 1985—Center for Analytical Chemistry,

Natl. Bur. Stand. (U.S.), NBSIR 85-3272,

182 pages (November 1985). Order from

the Center for Analytical Chemistry, A309

Chemistry Building, National Bureau of Standards, Gaithersburg, MD 20899,

301/921-2851.

The measurement of vitamins in blood serum to determine their role in preventing cancer, the analysis of trace elements in foods, and the measurement of toxic gases

at the parts per billion level are just a few

of the programs described in this NBS

report. The document gives capsule summaries of 1985 research in the three major

divisions— inorganic analytical, organic

analytical, and gas and particulate

science—within the Bureau's Center for Analytical Chemistry. Major publications

and activities are listed, along with tallies of analytical chemistry Standard Reference

Materials produced by the center in 1985. (These materials, sold by NBS, are widely

used by industries such as metals and

chemicals as well as in clinical and

environmental laboratories to improve

analytical measurements.) The report also

reflects basic research on new measure- ment techniques and analytical chemistry's

burgeoning role in providing data for highly

complex sample types—samples such as hazardous chemical and nuclear wastes, body fluids, plant and animal tissues, foods, and high-technology materials.

ORDERING INFORMATION

To order publications from NTIS, send

request with payment to: National Technical

Information Service, Springfield, VA 22161.

Publications can be ordered from GPO by

mailing order with payment to: Superintendent of Documents, U.S. Government Printing Office, Washington,

DC 20402.

31
CONFERENCE CALENDAR

10th Triennial Congress of the

International Council for Building

Research, Studies, and Documentation

(CIB), Convention Center, Washington,

DC

September 21-26, 1986

This congress will provide participants an

opportunity to discover some of the most

important innovations in building practices,

research, and development. Over 500

experts in various building-related fields from around the world will deliver pre- sentations addressing issues in the areas of advancing building technology for the computer age; shelter for the homeless in developing nations; and translating research into practice. Topics within these

areas include; performance and durability of materials; automated building systems;

integration of information for building

projects; incentives, finance, and

economics; national and international shelter programs; and robotics in construction. Sponsored by the Building

Research Board of the National Research

Council of the National Academies of Sciences and Engineering and NBS.

Contact: Noel J. Raufaste, CIB.86 Director, B226 Building Research Building, NBS,

Gaithersburg, MD 20899, 301/921-3106.

7986 Meeting of the National

Conference of Standards Laboratories,

25 Years of Measurement Progress,

NBS, Gaithersburg, MD

October 6-9, 1986

Emphasis at this conference will be on new

developments in metrology and new

management techniques to efficiently utilize resources, as well as the emerging role of the metrologist in contributing to improved

product quality and reliability. In addition, the program will give timely recognition to the pioneers of measurement science and

will take a look at the progress in measurement science over the past 25

years. Workshops will include special

hands-on sessions to keep the metrology

manager and engineer abreast of tech- nological advances and new innovative

ideas. Since the National Conference of Standards Laboratories (NCSL) will be

celebrating its 25th anniversary during

32

1986, the program will include a special session dealing with the history and

progress of the organization. Sponsored by

NCSL and NBS. Contact: Ernest L. Garner, B362 Physics Building, NBS, Gaithersburg,

MD 20899, 301/921-2805.

Thirty-Second Annual Conference on

Bioassay, Analytical, and Environmental

Radiochemistry, NBS, Gaithersburg, MD

October 21-23, 1986

The ability to quantify minute amounts of radionuclides in a variety of difficult matrices continues to be important for the study and protection of humans and the environment. In this informal conference,

researchers and analysts from government,

industry, and academia will discuss new,

improved, or even problem analytical methods, interpret subsequent data, and

evaluate health and environmental impli- cations. The scope for the conference will include in vivo and in vitro bioassay,

analytical method development, distribution and partition of radionuclides in the environment, and modeling and health significance of radionuclide pathways to humans. Sponsored by NBS, the U.S. Environmental Protection Agency, the U.S. Nuclear Regulatory Commission, and the

U.S. Department of Energy. Contact: Dr. Kenneth Inn, C114 Radiation Physics

Building, NBS, Gaithersburg, MD 20899,

301/921-2383.

Annual Conference on Fire Research,

NBS, Gaithersburg, MD

November 3-7, 1986

This conference sponsored by the NBS

Center for Fire Research (CFR) will promote

scientific exchange among technical peer groups in five fire research areas—fire growth, material combustion science and

measurement, combustion product

generation and impact, modeling and

measuring fire-generated environments and

hazards, and extinction. Within this context, the CFR in-house and research grant pro- grams will be presented, as well as a

limited number of outside projects. Discussion of new ideas, further research needs, and technical priorities will also be

encouraged. Contact Sonya Cherry, A247

Polymer Building, NBS, Gaithersburg,

MD 20899, 301/921-3845.

7986 International Workshop on

Moisture Measurement and Control for Microelectronics, NBS, Gaithersburg,

MD

November 12-14, 1986

The increasing use of organic materials in hybrid, VLSI, and VHSIC packages, the

attractive use of lower-cost plastic parts, together with the inevitable presence of moisture in the packaging environment

challenge component reliability. In order to point out the effects of moisture on

microelectronics and to review the state- of-the-art in the means to better measure and control a package moisture rate, this fourth workshop will provide a wide inter- national forum for exchange of information and ideas among analysts, semiconductor

manufacturers, users, and others interested

in packaging reliability. Sponsored by the Rome Air Development Center and NBS.

Contact: Stanley Ruth berg, A331

Technology Building, NBS, Gaithersburg,

MD 20899, 301/921-3625.

Scientific Software for Supercomputing,

NBS, Gaithersburg, MD

November 17-20, 1986

Potential users of supercomputers need to learn about how supercomputing relates to

their problems, and they need hands-on

training in the effective use of super- computing facilities. Experience has shown

that merely providing supercomputer

machine cycles does not give sufficient motivation to get scientists involved in more

sophisticated calculations using super- computers. This workshop will answer the

users' needs by providing participants with some of the background and tools necessary to effectively use supercomputer

resources. The workshop will present case

studies, which will be combined with

tutorials, and workshops that will provide hands-on training. Sponsored by NBS and

the Society for Industrial and Applied

Mathematics. Contact: Dr. Francis E. Sullivan, A151 Technology Building, NBS,

Gaithersburg, MD 20899, 301/921-

3395.

V.-U8 OOVT.RNMKNT PRINT1NO OKF1CE 1986 - 491-097 - 814/W578
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 Institute for Computer Sciences and Technology, and the Institute for Materials Sci- ence 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 ser- vices 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, pro- duces, 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 ser- vices 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; pro- vides engineering measurement 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 re- sults 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 sci- entific and technical services to aid federal agencies in the selection, acquisition, application, and use of computer

technology to improve effectiveness and

economy in government operations in ac- cordance with Public Law 89-306 (40 U.S.C. 759), relevant Executive Orders,

and other directives; carries out this mission by managing the Federal Information Processing Standards Program, de- veloping 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 pro- vides the technical foundation for computer-related policies 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 funda- mental to the processing, structure, properties, and performance of materials; ad- dresses 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 pro- grams in nuclear reactor radiation re- search and nondestructive evaluation; and broadly disseminates generic technical information resulting from its pro- grams. The institute consists of the fol- lowing divisions:

• Nondestructive Evaluation

• Inorganic Materials

• Fracture and Deformation

• Polymers

• Metallurgy

• Reactor Radiation
U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

Gaithersburg, MD 20899

OFFICIAL BUSINESS

Penalty for Private Use, $300

BULK RATE POSTAGE & FEES PAID NBS

PERMIT No. G195