On the cover: With the signing of the Omnibus Trade and Competitiveness

Act on August 23, the National Bureau of Standards became the National Institute of Standards and

Technology. See article on page 5.
National Institute of Standards and Technology

NATIONAL INSTITUTE OF STANDARDS &

Research Information Center

Gaithersburg, MD 20899

/lo. 1^3

Research Repi

u s, DEPARTMENT OF COMMERCE

C. William Verity, Secretary

National Institute of Standards and Technology

Ernest Ambler, Director

National institute of Standards and Tectinology

Gaithersburg, MD 20899

301/975-2000

National institute of Standards and Technology

Boulder, CO 80303

301/497-3000

October 1988

NIST Special Publication 743

Prepared by the Public Information

Division A903 Administration Building

National Institute of Standards and Technology

Gaithersburg, MD 20899

301/975-2762

Library of Congress

Catalog Card Number: 88-600590

Any mention of commercial products

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

by the National Institute of Standards and Technology nor does it imply that the products mentioned are necessarily

the best available for the purpose. / V \

Research Update

NBS Has New Name, Expanded Role 5

Can We Talk? Speech Recognition Research at NIST 8

Pinpointing the Origin of Historical Artifacts 1

Advanced Materials: From Laboratory to Production Line 14

Five NIST Projects Win R&D 100 Awards 17

Biotech Center Names Top Officials 20

High-Resolution Structure for Chymosin Solved 22

New Technique Automates Sequencing of DNA 23

Role of Inflammatory Cells in DNA Damage Described 24

Laser Cooling Limit Broken 25

Tracing the Sources of Industrial Emissions 27

Helping Industry Find Substitute CFC's 28

New Publications 30

Conference Calendar 32

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

Turning Shuttle Tanks Into Space

Labs

Can the space shuttle's fuel tanks be

turned into manned, orbiting science

labs? NIST is working with the University

Corporation for Atmospheric Research

(UCAR), NASA, and others looking at the technical and economic feasibility of such a conversion. The 30-ton tanks—as wide as a Boeing 747 and the height of a

13-story building—now are jettisoned

and burn up in the atmosphere just before the shuttle achieves orbit. Initially, the NIST researchers will be developing

computer models to help determine the

structural stability of the tanks when

equipped with scientific instruments. Future work at NIST will include structural analysis to help develop cost-effective techniques for converting the tanks into manned laboratories.

Program Seeks Researchers in Polymer Composites

Researchers in industry, universities, and

government are invited to participate in an NIST research program that addresses the most critical barriers in high-performance polymer composite

processing which producers must over- come to meet increasing international competition. The U.S. market for hightechnology plastic products, valued at approximately $1.6 billion in 1987, is ex- pected to grow to $10 billion before the year 2000. The United States now has

the technological lead in the use of highperformance polymer composites in defense and aerospace applications. In high-volume mass markets, however,

U.S. industries face intense competition.

Polymer composites are reinforced

plastics carefully engineered to meet

specific performance requirements. By

combining polymer resins with reinforce- ments such as graphite fibers, very versatile, lightweight, and high-strength

materials can be made. Examples in- clude jet aircraft parts and sporting

goods like tennis rackets and fishing rods. For information contact Donald L. Hunston, A209 Polymer Building, NIST,

Gaithersburg, MD 20899, 301/975-6837.

Steel Oil Tanks Should Be

Evaluated

Steel oil tanks should be evaluated to en- sure they are tough enough to keep

small cracks from developing into catastrophic failures, according to NIST

researchers. The Institute made that rec- ommendation after investigating the January 2, 1988, failure of an Ashland

Petroleum Company tank near Pitts- burgh, Pa., which spilled nearly 2 million gallons of oil into the Monogahela River. NIST found that a brittle fracture that began as a 3/4-inch-wide flaw in the tank

shell spread quickly and ripped the vessel wide open because the steel was not tough enough to stop the fracture. NIST recommended that standards be

reviewed to identify those with provisions

for sufficient fracture toughness to pre- vent catastrophic brittle fracture at design stresses and temperatures. Also,

steel to be used in new or reconstructed

tanks should comply with these provisions, according to NIST researchers. If a tank lacks sufficient fracture toughness, NIST suggested taking remedial actions—such as converting the tank to higher temperature use, retiring the tank,

or installing special crack "arresters."

NIST also said that standard protocols

need to be developed to test and assess

the fracture of steel in tanks which lack adequate documentation.

NIST Database on Engineering

Properties of Hydrocarbons

A new database for calculating viscosity,

density, and other important engineering

property data of hydrocarbons—natural gas, petroleum, and organic materials, in eluding mixtures of fluids—has been

developed by NIST. The "DDMIX"

database was developed as part of a re- search project sponsored by an industry

consortium of petroleum, chemical, and

gas processing firms. Available on a

floppy disk for personal computers, it pro

vides rapid access to important information on the storage and transportation of

fluids, and for the design of new chemical processes. Among other things, the program al- lows users to calculate quickly various

thermodynamic and transport properties

of fluid mixtures. These mixtures can be

selected from any of 17 possible pure components such as carbon dioxide,

methane, ethane, nitrogen, oxygen, and

heavier hydrocarbons such as hexane

and heptane. Order DDMIX—fvlixture Property Program (1988), NIST Standard

Reference Database 14, a floppy disk for personal computers, for $400 from the Of

fice of Standard Reference Data, A323

Physics Building, NIST, Gaithersburg,

MD 20899, 301/975-2208.

2
Advanced Shipyard Manufacturing

System Dedicated

Officials of NIST and ttie U.S. Navy's

Naval Sea Systems Command (NAVSEA)

on July 19, 1988, dedicated a state-of- the-art robotic manufacturing system de- signed and assembled by NIST for the Navy's Mare Island (Calif.) Naval Shipyard. The Mare Island workstation,

scheduled for delivery to the shipyard

later this year, will be one of a handful of

facilities in the United States capable of operating, largely untended, 24 hours a

day, 5 days a week.

Consisting of an automated lathe, industrial robot, automated storage and retrieval system, and various control computers, the workstation incorporates

several advanced automation tech- niques. It is designed to produce any of 40 different pipe connector parts used to suppress noise in nuclear submarines.

Such parts are not stockpiled and are produced on demand when the submarine is serviced. Current manual pro- duction methods require about 17 hours

to make one of these parts. The Mare Is- land workstation can machine the same

part in under 30 minutes and is already

turning out parts for the Navy on a trial basis. The advanced manufacturing tech- niques used in the workstation are applicable to many manufacturing operations.

NIST Inks ISDN Agreements With

Nynex, Bellcore

NIST has signed agreements with NYNEX and Bell Communications Re- search (Bellcore) to develop test

methods for evaluating product confor- mance to Integrated Services Digital Net- work (ISDN) standards. ISDN is a new

telecommunications technology that makes it possible to send and receive

voice, data, and image signals simul- taneously over digital telephone net- works. When completed, the test methods will be publicly available and

will help speed up the introduction of commercial products conforming to the standards. A researcher from Bellcore

the research and development arm of the seven regional Bell holding companies

is already at NIST and others from Bell- core and NYNEX may follow. Both

NYNEX and Bellcore will open up their

facilities to NIST researchers. The multi- year research program is expected to lead to public demonstrations and an ISDN network for the nationwide testing

of ISDN-compatible products.

Mare Island workstation project manager

Kang Lee demonstrates ttie control system to NAVSEA Deputy Commander R.A. Roger B. Home, observed by John Lyons, director of the NIST National Engineering Laboratory.

Gallium Triple Point To Serve as

Fixed Point

The present scale (International Practical Temperature Scale (IPTS-68)) used to calibrate all thermometers will be re- placed in 1990 with a new scale which

better approximates the thermodynamic

temperature T. Preparing for this change,

standards laboratories around the world

are determining the thermodynamic

temperatures of highly reproducible fixed points such as gallium's triple point (Tg),

3
where the solid, liquid, and vapor phases

are in equilibrium. Based on work at NIST, Tg has now been proposed as a

defining fixed point in future temperature

scales. NIST researchers determined Tg

(302.91 69 ± 0.0005 K; about 85.6 °F) by

making exceedingly accurate measure- ments of the speed of sound in argon. In making their measurement, the re- searchers exploited an instrument used

to redetermine the universal gas constant

(R). Their new acoustic techniques are simpler and more accurate than other techniques for measuring the thermodynamic temperature.

New Technique for X-Ray

Fluorescence Spectroscopy

A new technique in molecular spectroscopy under study by scientists from

NIST, Brookhaven National Laboratory,

and Indiana University allows re- searchers to take "snapshots" of the electronic energy states of free molecules on

a time scale so fast that the molecules can be effectively "frozen" in a particular

spatial orientation. The result is an en- hanced sensitivity to molecular-symmetry

effects in spectroscopy not previously at- tained. The team has made measure- ments of polarized x-ray fluorescence

from methyl chloride, in which polarization of the decay fluorescence of specific electronic states in the molecule clearly

depends on the symmetry of the molecular orbitals involved. These experiments

demonstrate the feasibility of using this technique to obtain orientation and dynamical information for specific electronic states in molecules. The structure

of active sites of large molecules, such

as proteins, could be studied in this fashion in "natural" states without requiring

crystallization.

High-Resolution Measurements

of Thin-Film Interfaces

The "microstructure" of the interface be- tween a thin film and a bulk material is of extreme importance to the semiconductor industry because it often controls the

electrical behavior of a semiconductor

device. It is difficult to measure, however:

Surface science techniques can only

probe a solid interface destructively, by

digging down to it. With more penetrating

probes, the information from the interface

is lost in the mass of responses from the bulk material. Now researchers from

NIST, the University of Tennessee, Oak

Ridge National Laboratory, and

Lawrence Berkeley Laboratory have

tested a technique to obtain greatly en- hanced responses—up to 50 times, so

far—from thin-film interface. The trick is to make multilayer "sandwiches" of alter- nating substrate and film and use soft x- ray fluorescence, exciting the core

electrons of the atoms to measure position and chemical species. Feasibility

studies on an ultra-high sensitivity

spectrometer in the NIST facility at the National Synchrotron Light Source

(Brookhaven) used silicon and carbon

and could discern the interface characteristics of films as thin as 3 angstroms.

JANAF Thermoqhemical Tables

Available Online

The third edition of the (Joint-Army-NavyAir Force) JANAF Thermochemical Tables, published by NIST, has been

computerized to provide scientists and

engineers with rapid access to information on the performance of materials at high temperatures. The database is avail- able to subscribers on STN International

(Scientific and Technical Network), an online private sector retrieval service

offered worldwide. The numerical data

can be used to make quick performance

calculations for chemical reactors such

as rocket engines, air pollution control equipment, internal combustion engines,

coal gasifiers, and furnaces. The

database is designed to list in one table

all of the values for a given property of a chemical compound when the values for that compound appear in more than one

tabulation. Information can be obtained

by chemical name, the formula, or by the Chemical Abstracts Registry Number.

For information on the new JANAF file through STN, contact the Office of Standard Reference Data, A323 Physics Building, NIST, Gaithersburg, MD 20899,

301/975-2208.

Low-Alloy Steel Calibration

Standards Announced

NIST has developed a new graded series of seven low-alloy steel standards for calibrating optical emission and x-ray fluorescence spectrometers. Great care has been used in preparing these materials to obtain a high level of homogeneity

to meet the demands of new, highly pre- cise instruments used in the quality control of alloy materials. Standard

Reference Materials (SRM's) 1761-1767,

prepared in consultation with ASTM and

industry, are available for $135 each in the form of disks approximately 34 mm in diameter and 19 mm thick. To obtain in- formation on the certified values of each

disk, or to order the new graded series of calibration standards, contact the Office

of Standard Reference Materials, B31

Chemistry Building, NIST, Gaithersburg,

MD 20899, 301/975-OSRM (6776).

4
NBS Has New Name,

Expanded Role

Somethings are obvious straightaway—the letterhead, for ex- ample, or the highway signs. Other things gradually occur to one:

"What about contracts? What about employee passes and parking

decals?" On August 23rd, as a result of the Omnibus Trade and

Competitiveness Act, the National Bureau of Standards formally

became the National Institute of Standards and Technology (NIST).

The Trade Act, or rather part of it—Title 5, Subtitle B, Part 1, the Technology Competitiveness

Act—goes on to make other changes, changes which constitute probably the most important

legislation affecting the agency

since it was founded in 1901

"I believe the most significant

part of this legislation is found

right up front in the list of functions assigned to the agency,"

notes NIST Director Ernest Ambler. "We now have a direct, unambiguous charge to work

closely with industry on the

development and use of the new

technologies that U.S. companies

need to stay competitive in the world marketplace."

The law states that NIST is in- tended:

to assist industry in the development of technology and proce- dures needed to improve

quality, to modernize manufacturing processes, to ensure

product reliability, manufacturability, functionality, and cost-ef- fectiveness, and to facilitate the more rapid commercialization,

especially by small-and

medium-sized companies

throughout the United States, of products based on new scientific discoveries in fields such

as automation, electronics, ad- vanced materials, biotech- nology, and optical

technologies;

The phrase "small- and

medium-sized companies" recurs

often throughout the act, observes Ambler. "The legislation

recognizes that smaller companies have an important role to

play in improving our national competitiveness through improve- ments in productivity and quality. "Of course, we've long had in- teractions and cooperative re- search programs with small companies as well as major in- dustrial firms. Technology transfer

is not a new story here. But it has

always been more difficult to assist the smaller companies be- cause of their sheer numbers and

because of limited resources, both theirs and ours.

"This act provides new mechanisms for working in cooperation

with economic and technological

development groups in state and

local governments and in other re- gional institutions, which is a very

attractive solution to these

problems."

The act describes several new

NIST programs based on this cooperative program theme, in- cluding a series of "Regional
Centers for the Transfer of Manufacturing Technology" that will be

affiliated with non-profit institu- tions or organizations; a program

to provide assistance and make

federal technology available to state and local technology pro- grams and technology extension

services; and an "Advanced

Technology Program" to en- courage the commercialization of new high-technology products.

The act also establishes a Department of Commerce (DOC)

"Clearinghouse for State and

Local Initiatives on Productivity,

Technology, and Innovation" to provide technical and analytical

help to state and local officials making decisions on technology

policy.

While the legislation adds major new programs, it also reinforces

the agency's role as the nation's measurement and standards re- search laboratory. NIST will continue to serve as the nation's central laboratory for developing

and disseminating measurement

standards and scientific data for science, engineering, manufacturing, commerce, industry, and

public safety.

Manufacturing Technology

Centers

The regional centers are intended

to be local resources, where

small- and medium-sized manufacturing firms in particular could

go for direct technical and

managerial support in automating

and modernizing their facilities. As envisioned in the act, these

centers will help businesses

develop technically and financially sound plans for modernizing their production. Advanced

production facilities are to be set up in the centers to demonstrate new technologies and provide a

training facility for regional firms. Centers may actually loan auto- mated manufacturing equipment

NIST will continue to

serve as the nation's

central laboratory for

developing and disseminating measurement

standards and scientific data for science,

engineering, manufacturing, commerce, industry, and public

safety.

to selected companies on a short- term basis to help get them

started. They will sponsor the

transfer of modern manufacturing

and quality control techniques

developed in NIST labs, and

otherwise draw on the scientific resources of NIST, particularly the technology cultivated at the NIST

Automated Manufacturing Re- search Facility. NIST is to create these centers

in cooperative agreements with non-profit organizations established by state and local governments, universities, or consortia.

Depending on the availability of money, NIST may provide up to 50 percent (limited to $3 million annually) of the operating funds

for these centers for their first 3

years, and decreasing amounts

for the next 3 years. After 6 years,

the centers should be self- supporting.

In anticipation of this legislation, a limited effort was initiated in fis- cal year 1988.

Technology Extension

Programs

At most, there will probably never be more than a handful of the re- gional manufacturing technology

centers, but the act also instructs NIST to forge new ties to the many state and local technology

extension services that have

been created throughout the

country.

NIST can establish cooperative

agreements with state or local programs to develop programs

that transfer federally developed

technology to business within

their area. State and local extension services typically emphasize

business advice rather than dealing with sophisticated tech- nology. Ties with NIST will help to coordinate the state and local ex- tension services with federal tech- nology transfer programs. Through workshops, seminars,

and other mechanisms, NIST

plans to help technology extension agents make the best use of federal resources.
Evaluation of Inventions

One new program assigned to NIST under the act is to reach out

to individuals: the Non-Energy In- ventions Program. The somewhat

unusual name is because the pro- gram is meant to complement the

Institute's existing—and quite successful—Energy-Related In- ventions Program sponsored by

the Department of Energy.

Under the latter program,

started in 1975, any inventor can

submit an invention to NIST for evaluation, so long as it is in some way related to producing or conserving energy. Drawing on a

national network of science and

engineering consultants, NIST

for free—evaluates the technical

feasibility and marketability of the

invention: Will it work? Will anyone

buy it? Inventions with a favorable re- view (there have been 450 so far) are recommended to the Department of Energy for support, which can include development grants

or marketing assistance. The Non-Energy Invention pro- gram is expected to work in a similar fashion, except that recom- mendations for support will go

elsewhere, such as to the new

NIST Advanced Technology

Program.

Advanced Technology

Program

Through the Advanced Technology Program, NIST is directed

to speed the commercialization of new technology and the development of new, generic manufacturing techniques. Under the Technology Competitiveness Act, NIST may support or even participate in research consortia to develop and test new equipment

or production processes, pro- vided that they are "generic" to a

particular industry or group of industries. The program will be aimed at small- to medium-sized, hightechnology firms or consortia. The

idea is to "leverage" the relatively small financial resources of NIST

by using the Institute's support to encourage private investment in each project. Inventions receiving favorable evaluations from the Non-Energy Inventions Program

will be natural candidates for the advanced technology program.

Clearinghouse

Another potentially useful creation

of the act is the DOC "Clearinghouse for State and Local Initiatives on Productivity, Technology,

and Innovation." The clearinghouse IS to gather and analyze in- formation on the many state and

local technology development

programs across the nation. The

idea is to develop a central base

of information on what programs

are available, what has been

tried, and what the results have

been. The clearinghouse will be a resource for state and local governments when deciding on new technology policies. The in- formation will be shared through

workshops and other mechanisms.

Planning Under Way

Exactly how the new programs

and activities will be accomplished is still under discussion. A

new organization plan must be

drawn up and submitted to the Congress for approval . At present,

the programs for regional manufacturing technology centers and

inventions evaluation have

received some funding. Still, according to the NIST Director, the new legislation represents

welcome recognition of a job well done.

"Of all the hundreds of laboratories in the federal government, we

are the sole agency with the mission of directly serving industry,

which is why we were singled out by this legislation," says Ambler.

"During the past 87 years as the National Bureau of Standards,

this agency developed a reputation, of which we are all quite

proud, for the highest standards

of technical competence and

objectivity. "As the National Institute of Standards and Technology, we

will continue to maintain the same

high standards and to pursue

excellence."

by Michael Baum

NIST Public Affairs Specialip'
Can We Talk?

Speech Recognition Research! at NIST

Computers that understand spoken language and can carry on conversations with humans are a science fiction staple. But in reality,

comprehending and responding to spoken language is a difficult

process for most computers. Interactions between people and

machines still are limited mostly to communicating through

mechanical means such as a keyboard.

This is changing slowly as measure the performance of autoscientists in both government and mafic speech recognizers. Basic

industry are addressing some of research as well as measurement

methods are needed to advance

the technology, says Pallett.

the problems. "We have a long

way to go before a machine will be able to understand naturallyspoken human speech," says David Pallett, manager of the au- tomated recognition group at the National Institute of Standards

and Technology. "But the door is beginning to open as developments in speech technology are challenging the computer keyboard as the only means of inter- acting with complex systems," he

says. At NIST, Pallett and his group

are helping remove the barriers to recognizing and understanding

continuous speech and spoken

natural language. Working with the Defense Advanced Research

Projects Agency (DARPA), the NIST researchers are developing

improved algorithms and soft- ware for phonetically-based rec- ognition of speech and ways to

How They Work

Speech-recognition systems are

available now, and the U.S. market is growing; some analysts

predict it will reach $1 billion by

'We are trying to

codify linguistic knowledge into something

measurable."

1990. But even successful commercial devices are extremely

limited. For the rjiost part, they

recognize only single words,

such as "good" or "correction," or short phrases. People using them

must talk slowly and clearly, pausing between each word—not at

all a natural way of speaking. The

devices are especially useful for workers entering data while their

hands and eyes are busy or where voice input is faster or more convenient.

Most of these machines use a

complicated, electronic process

of matching soundwave patterns

of spoken words to patterns stored in the computer's memory.

The process is very accurate for a speaker-dependent system

which IS "trained" by each

speaker reading to the machine

all the words—typically 100 to 200—it should recognize.

Speaker-independent devices can be built to recognize the same word or phrase as spoken

by many people. But the chances

for errors are greater and the vo- cabularies much smaller.

Vowel Recognition

The ultimate, a computer that people can talk to as they would

talk to another person, is still only a tantalizing prospect. Humans

have well-developed abilities to adapt to and accommodate varia-
bilities in speech. But what the

brain does routinely is enormously difficult for a machine. People tend to run words

together when they talk, making it

difficult for a machine to know

when one word stops and

another begins. "What do you

want?" might sound like, "Waddayah want?" In addition, people

tend to smear sounds together

called coarticulation. For ex- ample, the "d" and "y" in the middle of "did you" might come

out as a "j."

In spite of the obstacles, the quest continues and progress is being made. Along with re- searchers at universities and else- where, the NIST group is attempting to emulate the way

humans recognize speech by

developing algorithms and soft- ware for phonetically-based rec- ognition of speech. "We are trying

to codify linguistic knowledge into something measurable," says NIST computer scientist James

Hieronymus.

Methods such as pattern-matching work well for word-recognition

devices; but Hieronymus believes

the key to continuous speech rec- ognition by a machine is computer programs which can pick

out speech sounds, such as vowels and consonants, and use them to identify words. The NIST

researchers are concentrating on

a vowel-recognition system which

accounts for phonetic context

sounds on either side of the vowel. "We are analyzing how

vowels are formed, as well as what effect coarticulation has on

the sound of a vowel," says Hieronymus.

Coarticulation—running sounds

together—poses a particular

problem for a machine. According to Hieronymus, vowel recognition algorithms which do not take

coarticulation into account will correctly recognize phonemes in continuous speech only 75 per- cent of the time. "By developing

methods which explicitly model

the phonetic context, higher

levels of performance are ex- pected to be achieved," he reports. In fact, recognition

machines incorporating the NIST

method—which does account for coarticulation—can correctly identify vowels in continuous speech

85 percent of the time. "It is a difficult process," says Hieronymus,

NIST researchers David Pallett (left) and James Hieronymus discuss a computer program designed to recognize vowels.

"but we believe that a good vowel

recognition system will provide

the anchor for successful, continu- ous speech recognizers."

Measuring 'Widgets'

An important link in developing

the technology is finding a way to measure performance of speech

recognition devices. "Technology

does not come from a crystal

ball," says Pallett. "When you are developing a new 'widget' you

build a prototype, test it, evaluate

its performance, and if it doesn't measure up, work out the kinks, build another one, and start the
process over." The idea is the same with speech recognition

systems: To make progress it is

vital to evaluate performance.

Others agree. A study by the Committee on Computerized

Speech Recognition Technologies of the National Research

Council says, "The importance of performance measurement

techniques cannot be over-em- phasized since they provide the data for decisions about system

design and effectiveness." Working with DARPA and in- dustry, Pallett and his group are developing ways to evaluate per- formance. DARPA IS interested in continuous speech technology to

REF; give THE names AND resources o f cru

HYP: give THAN names f cru Lsers SENTENCE 13 Correct 75 0» 9 86 ) Substitutions 16 7* 24) Subs of alpha/numeric 0 0% 0 2) Subs of mono-syllable 16 7% 21) Deletions 8 3» 1 8) Deletions of THE 0 0% 0 1 ) Dels of alpha/numeric 0 04 0 U

Dels of mono-syllable 8 3\ 1 8) Insertions 0 0% 0 2) Ins of alpha/numeric 0 0% 0 0) Ins of mono-syllable 0 0% 0 2) Errors 25 0% 3 34)

Bef. words 12 118)

Hyp. words 11 112) Aligned words 12 120)

Ref. unknown 0 0) Hyp. unknown 0 0) Merges 0 0) Merge candidates = 0 5) Splits 0 0) Split candidates = 0 1)

REF: give me alerts w ith „he last four hours

HYP: give me alerts w in .he last four hours SENTENCE 14 Correct 100 0% 8 94 ) Substitutions 0 0% 0 24) Subs of alpha/numeric 0 0% 0 2) Subs of mono-syllable 0 0% 0 21) Deletions 0 0% 0 8) Deletions of THE 0 0% 0 1) Dels of alpha/numeric 0 0% 0 1) Dels of mono-syllable 0 0* 0 8) Insertions 0 0* 0 2) Ins of alpha/numeric 0 0% 0 0) Ins of mono-syllable 0 0% 0 2) Errors 0 0* 0 34)

Ref. words 8 126)

Hyp. words e 120) Aligned words 8 128)

Ref. unknown 0 0) Hyp. unknown » 0 0) Merges 0 0) Merge candidates » 0 5) Splits 0 0) Split candidates = 0 1)

This printout of a test to evaluate per- formance of speecti recognition de- vices stiows words correctly identified as well as errors.

enable jet fighter pilots to talk to on-board computers for information on vital systems such as fuel consumption, or to query tactical databases—"Display the maximum speed of the Kennedy." The

NIST test methods will help identify the strengths and weaknesses

of these systems and determine

whether a proposed system will

An important link in

developing the technology is finding a way

to measure performance of speech recognition devices.

do the job—or compare systems

to see which performs best. Keeping in mind that speech

patterns vary because of differ- ences in physiology, sex, age, geographic origin, and education, how do you test a machine

fairly? Even if spoken by the same person, a particular word,

syllable, or other element of speech may vary in loudness and

pronunciation due to stresses such as physical exertion or

fatigue. The NIST test method

helps to overcome many of these

variables by using recorded

speech databases in which a number of speakers have read

the same vocabulary in a controlled environment. "Using re- corded material we can get a broad range of speech patterns

and performance. It also allows

the test to be replicated in the same way each time and ensures

that the test material was properly

entered into the system," says

Pallett. The NIST researchers also have

developed software which keeps

score of words correctly identified as well as errors. In a recent DARPA test for example, this re- corded request was read: "Give

the names and resources of cruisers that are in Bismark Sea." The computer's interpretation was, "Give than names *** re- sources of cruisers that are an

Bismark Sea." Results: Seventyfive percent of the words were

correctly identified; there were

two substitution errors and one

word was deleted. Interestingly, says Pallett, most of the errors in- volve one-syllable words. "These

words are difficult to recognize

because they are short and

frequently are not pronounced

carefully," he says. Although the final goal—a computer you can converse with—still seems very far off, Pallett is con- vinced it is possible. "Computers

that can listen and talk back are a grand idea, not only for business

and industry, but also as a way to open up computers and computerized information to a larger

population," says Pallett. "NIST is helping to achieve this goal by

laying the groundwork of measurement science and re- search," he says.

by Jan Kosko

NIST Public Affairs Specialist
I

Pinpointing tlie Origin of

Historicai Artifacts

n a remote Asian village, an archaeologist dusts off a dirt-encrusted

bronze art object. Though the object appears similar to many un- earthed in other excavations, a basic question must be answered

before it can be catalogued or displayed in a museum: Where did it originate? More specifically, where did the raw materials come from

that make up the object?

In many archaeological digs

worldwide, this question can be

answered readily through knowl- edge of culture and history. For other locations, however, limited background information makes

the task tougher. Objects from

the art market are also hard to place.

One of the most useful tech- niques of tracing an ancient artifact or verifying the authenticity of a piece is lead isotope ratio analysis. Scientists at the National Institute of Standards and Technology

are using the technique in col- laboration with museum re- searchers who seek to pinpoint

just where precious art pieces come from. Most recently, several organizations within the Smithsonian Institution have joined with NIST to study lead isotope ratios in samples from over 300 ancient

Chinese bronze ceremonial vessels. NIST has contributed instru- ment time, space in its custom

laboratory, and expertise in per- forming this specialized type of chemical analysis.

Many of the vessels studied are included in the collection of the Smithsonian's Arthur M. Sackler

Gallery, a museum of Oriental and Near-Eastern art that opened

One of the most useful

techniques of tracing

an ancient artifact or verifying the authenticity of a piece Is lead

Isotope ratio analysis.

recently in Washington, D.C. The

vessels are from three Chinese

dynasties: the Shang, Western

Zhou, and Eastern Zhou, which to- gether spanned the period 2500

to 221 B.C. "Lead isotopes are inherently

present in these bronze pieces," says Emile C. Joel, a chemist

from the Smithsonian's Conservation Analytical Laboratory who

has worked full time at NIST analyzing the Sackler vessels. "This

is because Chinese craftsmen

routinely added 5 percent lead or more to bronze alloys, making the molten metal more fluid so it would cast better." As part of the general examination of the vessels for preparation

of a catalog, samples were taken

for lead isotope analysis. Despite

the spotty information that exists on raw materials in ancient China,

project researchers were able to combine their findings with those

of art historians to determine that

different lead sources were used

during different dynasties. This al- lowed them to classify vessels

into their respective dynasties

and, in the process, approximate

the age of each piece.

Lead's Unique "Signature"

One of the best ways to reveal a bronze object's origin is to trace

the location of the foundry where

it was cast. This is not difficult—if lead samples or isotopic data are

available from mines used by the

11
foundries. Lead ore from each

mining location fias a unique iso- topic ratio "signature" because

amounts of three lead isotopes

lead 206, 207, and 208—formed

in nature as stable end-products

of uranium and thorium decay,

are discernibly different in most

geographic locations. In an analysis, the ratios of the three iso- topes to a fourth, the stable isotope lead 204, yield a signature characteristic of a particular lead deposit or mine location. This signature has remained constant through the smelting, alloying, and casting processes.

Lynus Barnes, right, NIST chemist and Emile Joel, a Smithsonian re- search chemist use a mass

spectrometer to determine lead iso- tope ratios in artifacts.

Therefore, if a vessel foundry

had used the same lead source

for a prolonged period, the pieces produced will have the same lead isotope signature. Even without knowing in advance

the signatures for a given geographic location, vessels from the same foundry or production center should group together as they

did in the Sackler research. Isotope tracing was a critical

link in cataloging the Chinese vessels, says Tom Chase, head conservator of the Sackler Gallery. "We've shown that, in some

cases, lead isotope ratios of particular Chinese bronze groups

are nearly identical. This is almost as good as an imprinted maker's

mark. Careful consideration of these results will put the technical

history of early Chinese metallurgy on a much firmer footing."

The isotope technique also is valuable for spotting art forgeries. This is because a fake piece or even a later addition to a real piece will be made with lead from

a different source than the original. Thus it will not produce the in- herent isotopic signature. The

NIST work has uncovered some

bogus objects.

How dependable is the tracing

technique? "Lead isotope analysis by itself is quite reliable, but

it's not perfect," says I. Lynus

Barnes, an NIST chemist and

project manager of the Sackler

isotope research. "I would say

that you've got about an 85 per- cent chance of identifying an object's origin using the method

alone if a signature has been determined through information or

samples from mines." Barnes

adds, however, that the isotopic

technique is valuable because it

is nearly always used in conjunction with some other data such as

existing historical information or other chemical analyses. When

combined, he says, the resulting

data have "high reliability." (Smithsonian researchers are demonstrating the value of blending two

methods, for example, when they

examine Spanish pottery glazes

by using lead isotope ratios in combination with trace element

analysis to help determine the

origins of those pieces.)

Besides exploiting the isotopic

technique's value in analyzing art- works. Institute scientists are using the method for other studies such as determining human

exposure to lead-based fuels or tracing the cause of a lead poisoning case.

A Powerful Analytical

Technique

At NIST, researchers on the Sackler Gallery work have used a

powerful analytical tool known as

a mass spectrometer to analyze

for lead isotope ratios. Only about

a millionth-of-a-gram sample is needed for the analysis, which

minimizes adverse effects to the

object. A series of steps is carried out that includes dissolving

the sample in acid and separating the lead electrochemically.

Then researchers perform the mass spectrometric analysis,

which sorts out by mass the sample's composition of the four lead isotopes. By comparing the

12
amounts of these isotopes in tlie sample, the unique signature can be determined, allowing the lead sample to be traced to its source.

In the past, NIST has been

quite successful in tracing arti- facts to such countries as Greece, Turkey, Italy, Spain,

Egypt, and England because

mines from these countries are well-known and lead samples or lead isotope data are readily avail- able. In the case of the Sackler

artworks, less was known historically about Chinese raw material sources, which made tracing more difficult and conclusions

harder to draw. Still, information gleaned from the research has

been useful in refining existing

origin criteria and will likely pro- vide information on the sources of raw materials used for vessel manufacture when additional knowledge of mining in ancient

China is obtained.

Where Did Columbus Land?

Isotope ratios also have been employed successfully in recent analyses of artifacts excavated

from San Salvador Island in the Bahamas—long regarded by

many historians as Christopher

Columbus' first landing site in the New World in 1492. NIST joined forces with researchers from The

Corning Museum of Glass (Corning, N.Y.), Corning Glass Works

(also Corning, N.Y.), and the Smithsonian Institution to analyze

lead isotope ratios in glass

beads, a metal buckle, a coin,

and several other excavated

pieces. The goal was to help de- termine if Columbus truly did land

first on the island or on any number of other suspected sites such

as Egg Island in the northern Bahamas. By determining where

and at about what time the San

Salvador pieces originated,

project researchers could state more reliably how the artifacts got on the island. Fortunately, all the pieces were

found to contain intentionally

added lead, which made the iso- tope ratio technique appropriate.

By matching isotopic signatures,

researchers were able to con- clude that many of the San Sal- vador artifacts originated in Spain

and could possibly have come

from Columbus' ships.

Despite the encouraging results

of the San Salvador analyses, no

firm conclusions were drawn. "A

lot more research and excavations still need to be done before we can say for sure where the landing site was," says Robert

Brill, a research scientist at The

Corning Museum of Glass who

has collaborated with NIST on

various research projects for 20

years. "What we've done with the isotope ratio data is add ammunition to the argument that Columbus first landed on San Salvador

Island. The objects we found

could very well have been among

those given to Indians on the day

of Columbus' first landfall in the New World."

What Lies Ahead

The NIST mass spectrometric lab

is also host to a large study of Turkish shipwrecks in collaboration with The Corning Museum,

Texas A & M University, Turkish researchers, and the Smithsonian. The first wreck in the

study, dating to about 1 150 A.D., was believed to be the earliest ex- ample of ship construction in the "modern" style—that is, laying the

keel first, then ribs and skin. Arti- facts from the ship—varied pieces of glasswork, mostly

were analyzed for lead isotopes.

Resulting information, which pinpointed the location of mines for lead used in the glass, was instru- mental in revising existing theories about early trade routes from

Turkey into northwestern Iran. A

similar study is currently under

way to analyze metal ingots and

fishing weights—which contain

lead—from a shipwreck found off the southern coast of Turkey that

IS believed to be over 3,000 years

old. Data from this work will help

historians map ancient trade

routes. NIST's Barnes says he expects

the Institute to continue collaborating with various organizations on

other similar lead isotope studies

of artifacts. "The technique has

proven its worth as an aid to historical documentation," he says. "Though it does have a few minor

drawbacks, it continues to be one

of the most valuable ways to gain

this background information."

by John Henkel

NIST Public Affairs Specialist
Advanced Materials:

From Laboratory to

Production Line

aterials are so basic to human progress that their importance is hard to overemphasize. Every technological advance, from the

first stone hammer to today's most complex integrated circuits,

sprang from the mastery of specific materials. Accomplishing

many of the nation's goals, such as the National Aerospace

Plane, faster computers, or electrical energy from nuclear fusion, hinges on

our ability to develop new materials that are far superior to those

used today^

Indeed, the technological and

economic goals of many other countries are also tied to ad- vances in materials, setting the stage for intense international competition. For example, more

than half of Japan's 13 priority re- search and development projects

involve materials science. In Europe, the Commission of European Communities has set up national and international cooperative programs that focus on advanced materials. Research on advanced ceramics, metal alloys, polymers, composites, and the new hightemperature superconductors

has already exposed some of the

future technological possibilities.

The ability to micro-engineer

these materials—to create submicroscopic structures and combinations of elements unknown in

nature—has resulted in properties and phenomena that until only recently were beyond the

imagination. Now that our imaginations have been piqued and

our appetites for innovation whetted, our challenge is to trans- form these materials from laboratory curiosities to viable products

and manufacturing processes.

At the National Institute of Standards and Technology, the

institute for Materials Science and

Engineering (IMSE) is responding

to this challenge in many ways, addressing scientific and

measurement issues that are

crucial to industry's success in exploiting the potential technological advantages of advanced

materials. Consistent with NIST's mission as a national science, engineering, technology, and

measurement laboratory, the activities of IMSE's six units emphasize research leading to the development of standards, test methods, and reference data and

materials. The guiding tenet for

this work is a simple maxim: If a

process or property cannot be

measured, then it is not completely understood. Inherent

in IMSE's mission is the need to develop scientific understanding

of the underlying physical and

chemical origins of the properties

being evaluated. Covering all classes of ad- vanced materials, as well as

major conventional materials, IMSE's research program investigates the relationship between

the structure and properties of materials and then applies the resulting knowledge to issues re- lated to the design, processing,

and performance of materials. Our approach encompasses the

full range of research and

development activities, from

basic studies to generic

applications.

Toward Automated Process

Control

In recent years, the focus of IMSE's attention has increasingly turned toward improving the un-
derstanding of materials processing. Our ultimate goal is to help U.S. industry develop real- time, automated systems of process control, so-called intelligent manufacturing methods

that improve product quality and

increase production efficiency.

As study after study has pointed

out, firms that emphasize product

quality throughout the manufacturing process, rather than at the end of the line only, will strengthen their competitive

position.

Intelligent processing of materials is itself the result of a process,

the evolutionary development and

application of scientific and en- gineering knowledge. Projects

under way in the five IMSE divi- sions and those managed by the

Office of Nondestructive Evaluation are gathering and evaluating

much-needed data on structures and properties of materials, at in- creasingly fine levels of detail and

under the increasingly extreme

environmental conditions that characterize many high-perform- ance applications. These data

support the development of process models, which relate the

specific properties of materials at each manufacturing step to the properties of the final product.

In tandem with data-gathering

and modeling efforts, IMSE re- searchers are building and refin- ing real-time sensors for in-process nondestructive measurements. They then develop strategies for coupling

r

!

on-line measurements with process models. This work establishes the foundation for the final step—merging sensors and models with automation technology to create a truly integrated manufacturing system. Without closedloop process-control, manufacturing methods will be inefficient, often failing to achieve the

carefully controlled microstructures that govern the perform- ance and reliability of advanced

materials. Process control is the common

thread that unifies IMSE's varied

technical activities—from the development and refinement of theory to innovative methods for on-line nondestructive evaluation. Our work exemplifies the increasingly close link between basic

scientific understanding and technological innovation.

Materials science engineer Jolin E. Blende!! prepares ceramic material samples for research on superconductors in the NIST ultra-clean ce- ramic processing laboratory.

Staff and Facilities

IMSE has a research staff of nearly 400 scientists, engineers,

and technicians, supported by a budget of about $40 million in 1987. Their efforts are enhanced

by the broad range of scientific and engineering expertise and in- strumentation available in other

parts of NIST, at its facilities in Gaithersburg, Md., and Boulder,

Colo. Collaborations are common: In fact, the multidisciplinary

makeup of NIST is an especially valuable asset in materials science and engineering, where

answers to important research

15
questions typically require contributions from physics, chemistry, the traditional materialsrelated disciplines, and many

other fields. Since it was created as the National Bureau of Standards in

1 901 , NIST has been a partner

with other federal agencies, in- dustry, and universities. In IMSE,

cooperation is flourishing. In 1987, 374 visiting scientists and

NIST's Cold Neutron Research

Facility, now under construction,

will be used for materials science and engineering research.

engineers conducted studies with IMSE researchers or used the Institute's specialized equipment, some of it unavailable anywhere

else in the United States. Our specialized facilities in- clude an array of metals and ce- ramics laboratories for controlled materials synthesis and process;- a 12-million-pound test rig for evaluating large-scale mechanical material properties; experimental stations for studying

aro-welding processes; special- ized small-angle and te/ture x-ray diffractometers particularly suited

for polymer characterization; and

16

a 20-megawatt reactor for neutron-scattering experiments.

Soon this arsenal of research

equipment will feature the nation's first dedicated facility for "cold neutron" studies, filling a serious void in the nation's materials science and engineering re- search. The NIST Cold Neutron Research Facility will provide

beams of deeply penetrating low- energy neutrons, essential for im- portant experiments that are

impractical or even impossible

with conventional neutron

sources. The facility itself will be

completed in the spring of 1989

with the first experimental stations becoming available later in the

year. By 1992, it will house 15 ex- perimental stations, including five

that will be instrumented and

operated by outside groups.

Five instruments are now being

developed, including a highresolution small-angle neutron

scattering spectrometer, a joint project of NIST and Exxon Re- search and Engineering. The new

facility, which will be available to

all U.S. users, is being designed

to exploit the most recent ad- vances in technology, resulting in research capabilities that exceed

those of cold neutron sources in other countries.

A National Resource

IMSE's research programs and

services are crafted according to the needs of U.S. industry. Obviously, we cannot tackle all of the many important issues that must be resolved before industry can fully achieve the promise of advanced materials and manufacturing methods. But, in many in- stances, we are uniquely

qualified to address a certain need. IMSE's data centers, for ex- ample, have stepped up their efforts to make vital, critically evaluated information—such as phase diagrams and corrosion- performance data—available to industry and the scientific community. The centers are also developing computer programs for searching materials databases

and for applying data to specific

problems.

Through conferences, workshops, and our many cooperative

programs with industry, we have

identified key areas where our re- search activities can make important contributions. IMSE's advanced ceramics program, begun in 1985 and now reaching

full strength in both staff and facilities, is one example; a second is our high-performance composites

project which emphasizes re- search relevant to high-voiume,

low-cost applications such as vehicles. Yet another example is IMSE's participation in the NIST- wide initiative to help U.S. in- dustry overcome the many

formidable obstacles that stand in the way of commercializing the new high-temperature

superconductors.

In these areas, and others, we

are working with industry to move

advanced materials from the laboratory to the production line.

by Lyie H. Schwartz

Director, NIST Institute for Materials Science and

Engineering
Five NIST Projects Win

R&D 100 Awards

Five

research projects in instrumeritation and measurement technology from the National Institute of Standards and Technology re- ceived R&D 100 Awards this year. R&D 100 Awards are bestowed

annually by Research & Development magazine to highlight 100 significant technical products of the preceding year. NIST has re- ceived 62 R&D 100 Awards since first entering the competition in 1973.

Descriptions of the awardwinning projects follow.

Optical Waveguide

Dosimeter

William L. McLaughlin of the NIST

Center for Radiation Research

and Branislav Radak, a guest

scientist from the Boris Kidric Institute in Yugoslavia, developed

an extraordinarily versatile ionizWilliam L. McLaughlin (top) and

Branislav Radak with the optical

waveguide dosimeter.

ing radiation dosimeter around

the concept of radiation-sensitive dyes.

Colorless compounds that take on color when irradiated,

"radiochromic dyes" have been in use for some years as one-shot,

disposable dosimeters for industrial radiation processing, an

application that McLaughlin

pioneered.

In the new invention, the dyes

are used in the core of a long

fiber-optic tube that can be coiled

into a small space, about 2 centimeters square. A light source at one end and a detector at the other read changes in the dye.

Because the light path can be

quite long even in a small detector, the instrument can be made

extremely sensitive. The optical

waveguide dosimeters can function over a range from about

0.005 to 10,000 gray. They will register either pulsed

or steady radiation fields, and

can measure accurately both

dose and dose rates of x and

gamma rays, neutrons, and

charged-particle beams.

By selecting from a variety of available radiochromic dyes and

plastics, researchers can tailor the dosimeters to have special

properties, such as matching the

radiation interaction characteristics of tissue for medical applications and radiation protection.

Cone Calorimeter

Vytenis Babrauskas and William

Twilley of the NIST Center for Fire Research developed an apparatus which provides the data criti- cal to predicting the fire hazard of a product from a small sample of material. The instrument, known as *he NIST Cone Calorimeter, measures the heat released and the

rate at which it is released, the time it takes for a material to ignite, the amount of smoke pro- duced, and the amount of several known toxic gases. Equipment

17
William Twilley (left) and Vytenis Babrauskas with the NIST cone cal- orimeter.

previously available could not measure as many fire properties.

Both the ASTM and the Inter- national Organization for Standardization are proposing

voluntary fire hazard test methods

based on the NIST Cone Calorimeter. Commercial units now

are sold by two U.S. manufacturers and a rapidly growing number are in use worldwide.

System for Absolute

Determination of Aqueous

Electrolyte Conductivity

Three NIST researchers constructed a device that determines

the "absolute" electrical conductivity of aqueous solutions and

can be used as a primary stand- ard against which other instru- ments may be compared.

The unique feature of the device is its measurement cell.

Other available systems rely on

cells of fixed geometry and work

by comparing a solution of un- known conductivity to a standard

calibration solution of known conductivity. These instruments typically are accurate to 0.1 percent.

The NIST system uses a varia- ble cell size and does not have to be calibrated. Because its results are traceable to the physical

standards of mass, length, and

electrical resistance, the new device provides an "absolute" conductivity determination with an accuracy of 0.02 percent.

It also features extremely accurate temperature control, which is important because conductivity

measurements are dependent on

temperature.

The device has many potential

applications. Standards laboratories desiring an absolute measuring system could adapt it. Other

laboratories could use the device

to calibrate existing conductivity

measuring instruments. Oceanographers could employ it in measuring seawater salinity, and

environmental scientists could determine dissolved solids. With minor modifications, the device also could be used as a

reliable indicator of water purity.

Such an instrument would be valu- able in the pharmaceutical, electrical power, and electronics

industries, which rely on pure

water for their products.

The NIST system for absolute

determination of aqueous electrolyte conductivity was developed

by Yung Chi Wu, Kenneth W.

Pratt, and William F. Koch, all of the NIST Center for Analytical

Chemistry.

Kenneth W. Pratt (I. to r), William F. Koch, and Yung Chi Wu developed a system for absolute determination of aqueous electrolyte conductivity.
Edward F. Kelley with the imagepreserving optical delay.

Image-Preserving Optical

Delay

Edward F. Kelley of the NIST

Center for Electronics and Electri- cal Engineering generated a

pioneering photographic "time machine" which—when used with a high-speed camera—permits

photographing events which oc- curred before the camera's shutter is opened.

The system, called an imagepreserving optical delay, differs from conventional photography

which records an event only

when the shutter is open.

This new device, an arrange- ment of optical components in- cluding mirrors and a crystal

shutter, allows researchers to take detailed, high-speed photographs of random—that is, nontriggered—events.

It is now used for processes

which last from 100 nanoseconds, or billionths of a second, to 10 microseconds, or millionths of a second, to study materials util- ized by the electric power

industry. This system stores optical im- ages of a random event long

enough so the shutter of a highspeed camera can be opened

and photographs taken of the processes leading to the random

event. Kelley has filed a patent

application on the system.

Functionally, the optical delay is equivalent to forcing the image to

travel an additional 120 meters

before it gets to the camera.

Using a series of concave and

planar mirrors, this path length is folded into about 4 meters. The system is rugged enough

to be used in a variety of settings.

Normal vibration, air currents, and airborne dust have minimal

effect on its operation.

Trace Measurement System

Computers known as multiprocessors use more than one computing element, or "processor," to simultaneously solve many

pieces of a problem. While multi- processors can speed the processing of data, they also have unique problems including

unbalanced processing loads, un- even flow of information, and an

increased likelihood of communications bottlenecks. Three researchers in the NIST

National Computer and Telecommunications Laboratory (formerly

Institute for Computer Sciences

and Technology) developed tools

to help measure the performance

of multiprocessors. The ability to

measure performance helps

users evaluate and compare machines and manufacturers im- prove future designs.

Through a single circuit board

added to the computer system,

the Trace Measurement System

TRAMS—can measure key

characteristics of a program such

as the time it takes to execute a piece of code and how frequently a piece of code is executed.

Unlike other measurement sys- tems now on the market, TRAMS

does not disturb the operation

The trace measurement system was

developed by John W. Roberts (I. to

r.), Robert J. Carpenter, and Alan

Mink.

being measured. Disturbances,

or "perturbations," can alter the performance of a multiprocessor,

making the results of the measure- ment meaningless.

Robert J. Carpenter, John W.

Roberts, and Alan Mink

developed the measurement sys- tem with partial sponsorship from

the Defense Advanced Research

Projects Agency.

19
Biotech Center Names

Top Officials

The

Center for Advanced Research in Biotechnology (CARB), a joint

research venture for academic, government, and industrial scientists, has named Thomas L. Poulos, 41 , as director and Walter J. Stevens, 44, as associate director. Poulos, a tenured professor of

biochemistry at The University of Maryland, had served as acting

director of CARB. He received his Ph.D. in biology from the University of

California at San Diego. His pro- gineenng, structure, and function

fessional experience includes as well as to offer the bio- work at Genex Corporation and technology community capabili- the University of California, San

Diego.

Stevens, a National Institute of Standards and Technology computational physicist, was awarded

his doctorate in chemical physics

from Indiana University. He has

been with NIST since 1975. CARB, founded in February

1984, as a first-of-its-kind, joint

"Protein engineering is

tlie future direction of

biotectinology

"

effort of The University of Maryland, NIST, and Montgomery

County, Md., is one of four re- search centers in the Maryland

Biotechnology Institute (MBI).

The mission of CARB is to fashion a world-class, multi- disciplinary center in protein enties not readily available in most

companies. In protein engineering, scientists alter a protein's

atomic structure to enhance its useful properties.

"Protein engineering is the fu- ture direction of biotechnology," says Poulos. "In time we should

be able to change the sequence

of amino acids [the building

blocks of proteins] at will and pro- duce novel, beneficial substances." One area of application

for wgrk at CARB is so-called

rational drug design. In this ap- proach researchers modify the

structure of a therapeutic protein

or drug so it attacks infection more effectively.

CARB has specifically targeted

five areas for focused research. The first, x-ray crystallography, is a long-standing technique to unravel the crystal structure of proteins. A second direction is two-dimensional nuclear magnetic resonance (2-D NMR) spectroscopy, an evolving method to determine the structure of proteins in solution. The two tech- niques complement one another. "We intend to use both crystallography and NMR at CARB.

While crystallography gives much

more precise structural data on

larger proteins, NMR provides more information on the dynamics

of proteins—how they wiggle and

wobble in solution," explains

Poulos. A third area is the modeling of protein structures. If researchers

grasp the structure then they can

predict the changes that lead to specific protein properties. This work requires substantial computer capabilities and will guide

the efforts of the experimental

group. A mini-supercomputer will be housed at CARB.

The fourth area is physical bio- chemistry, necessary to charac20
terize the properties of the novel

protein once it is produced. The

last direction is molecular bi- ology, which enables scientists to produce the novel protein in large

quantities.

"While a number of institutions enjoy expertise in crystallography, molecular biology, or NMR spectroscopy, few have

them all focused on a common

theme. What's unique about

CARB is the application of these

tools to protein structure and function problems under one roof," says Poulos.

Companies can participate in CARB research

by becoming industrial

affiliates, jointly sponsoring specific projects, or establishing

collaborative research

projects....

A variety of proteins are now

under investigation at CARB.

These include: ribonuclease, a standard protein—a digestive enzyme—and a model for studies in how proteins

fold. This folding affects their bio- logical activity. chymosin, or rennin, a protein

used in producing cheese. In col- laboration with a local biotech- nology company, CARB staff solved its structure recently. (See

article on page 22.)

cytochrome P450, an important enzyme in detoxification and

in carcinogenesis.

beta-lactamase, also known as

penicillinase, the protein central

to bacterial defense against penicillin-like antibiotics. Understanding its function is important to the

rational design of more effective

antibiotics. Companies can participate in CARB research by becoming industrial affiliates, jointly sponsoring specific projects, or establishing collaborative re- search projects under agree- ments which permit the company

to obtain a license to any proprietary technology resulting

directly from the research. CARB's new laboratory and office site, a 33,000-square-foot

building under construction at the Shady Grove Life Sciences

Center in Rockville, Md., sits on 50 acres donated by the county

The CARB facility, now under construction, will tiouse state-of-the-art laboratories for protein crystal- lography, molecular biology, NMR

spectroscopy, biophysical chemistry, and computer modeling.

through the Gudelsky Foundation.

Montgomery County provided

$9 million to construct the facility through a bond issue. The CARB

staff, expected to reach nearly

1 00 by 1 991 , has been using re- search space made available at NIST in Gaithersburg, Md., until the opening of the CARB building

later this fall.

by John S. Makulowich

NIST Public Affairs Specialist

21
High-Resoluflon Structure

for Chymosin Solved

By

solving a high-resolution structure for a cloned version of the

cheese-producing enzyme chynnosin, researchers at the Center

for Advanced Research in Biotechnology (CARB) have added this

fundamental protein to the growing list of biologically active

molecules with known structures. Chymosin, or rennin, was originally prepared from the stomach linings of calves for the making of

cheese, and is one of the oldest commercial enzymes. Working

with cloned chymosin expressed

in E. Coll bacteria, Gary Gilliland and colleagues at the National Institute of Standards and Technology and CARB mapped the

structure of the enzyme with a resolution of approximately 2.3 angstroms—comparatively high

resolution for a protein of 323

amino acids. The cloned chymosin was prepared by the

Gary Gilliland, an NIST research

scientist, studies the model of chymosin structure on a workstation

screen.

Genex Corporation.

Chemical techniques for deter- mining the composition of proteins—the sequence of amino

acids that make up the molecule—are fairly well developed. Determining the struc- ture of the protein, the three-di- mensional configuration of the molecule, is much less straightforward. This is in part because the most exact techniques, x-ray and

neutron crystallography, depend

on being able to crystallize the

protein, something which is still more of an art than a science.

Chymosin belongs to a class of enzymes called acid proteases

which have a number of interest- ing functions, according to

Gilliland. Chymosin itself is inter- esting because the particular

cloned version—bovine pancreatic chymosin—is the best enzyme for producing several

different types of cheese, and just

what makes it the best is a matter

of some commercial interest.

In addition, a similar enzyme,

rennin, is found in human blood,

and plays a role in regulating

blood pressure. An accurate

structure for chymosin can be one step on the path to developing extremely specific drugs for treating high blood pressure. More generally, according to

Gilliland, accurate structural infor- mation on chymosin will contribute to understanding what

governs the shape of proteins.

"The 'folding problem'—how

the amino acid sequence deter- mines the structure—is one of the biggest problems in biology

today," observes Gilliland. "The

rules that govern protein folding are very crudely understood at present, and an important aspect

of our work is the contribution to the data needed to determine

these rules." The chymosin structure was de- termined by Gilliland; Alex Wlodawer, of the National Cancer

Institute Frederick Cancer Re- search Facility; Joseph

Nachman, a guest scientist from

Israel; and Evon Windborne of The University of Maryland. M.B. 22
New Technique Automates

Sequencing of DNA

Researchers from EG&G Biomolecular and the National Institute of

Standards and Technology, in collaboration with the Center

for Advanced Research in Biotechnology (CARB), have

cooperated in developing an improved method for automating

DNA sequencing. Sequencing—determining the precise

sequence of DNA bases in a gene—is one of the most important tasks in

molecular biology and protein en- DNA fragments: A sheet of photo- chemistry used to sequence the graphic film is laid over the gel

plate and beta particles from the

labelled DNA fragments expose

the x-ray film. A researcher then

gineering. It is an extremely time

consuming job, with numerous

chances for error. The key problem is to detect the positions of

881 II il3B8

I'l,

_ / hAAk ('"'

j

\ I4PMj..,JJ

.jAMa

i U U' J" u

k

1 Tr,iTmcc(ciCfci*iT<xftwcmai«:cj«;cra(«fmT(mCTr.i»*«CTr€ it

Typical display of raw data from auto- mated sequencer stiows a short seg- ment of DNA. Each track is a separate DNA base.

DNA fragments arrayed in ladderlike patterns down the electro- phoretic gel plate used to separate them.

"Traditionally" this is done by

using radioisotopes to label the

It makes it possible to

design automated DNA

sequencers that are smaller and less expensive than those based

on fluorescent dyes.

examines the film to note the relative position of these small, dark

bands—typically 300 DNA bases

can be determined from a single

analysis. This part of the procedure is not only very laborious, but also the greatest source of error in DNA

sequencing.

Several techniques have been

developed to automate the process, but these rely on fluores- cent dyes as labels in lieu of radioisotopes. The dyes are ex- pensive and can interfere with the

DNA, or may introduce variations

in the mobility of the DNA fragments during electrophoresis.

In contrast, the new technique

makes use of the conventional

radioisotope-labeled DNA whose

behavior is comparatively well un- derstood. It uses radioactive phosphorous, which makes it possible to study other important

biomolecules such as RNA and

proteins. It makes it possible to design automated DNA se- quencers that are smaller and

less expensive than those based

on fluorescent dyes.

NIST researchers aided in developing standard sample

preparation procedures. Thciy also are studying the new tech- nique for use in obtaining quantitative as well as qualitative information. M.B.

23
Role of Inflammatory Cells

In DNA Damage Described

The

role of white blood cells in the formation of inflammationrelated malignant tumors should become clearer with a new list of

DNA damage assembled by researchers from the National Institute

of Standards and Technology and the Scripps Clinic and Research

Foundation. White blood cells, or "leukocytes," play a key role in

the defense against bacterial infection, but under the abnormal condition

of chronic inflammation they are

also associated with an increase

in malignant tumors, although the exact mechanism is not well understood.

The researchers quantitatively

analyzed damage done to the

four DNA bases by the action of these leukocytes. This damage is suspected to be an important link

in the formation of inflammationrelated tumors. The researchers studied a

class of leukocytes called neutrophils. When triggered by the pres- ence of foreign objects, such as

bacteria, neutrophils begin a so- called "respiratory burst" in which

oxygen molecules are reduced to superoxide radicals. The enzyme

superoxide dismutase (SOD) then transforms these radicals to hydrogen peroxide.

Researchers believe that in the presence of some metal ions such as the iron ions which are found in the cell, the hydrogen

peroxide is transformed to hydroxyl radicals, which are known

to cause DNA damage.

In a recently completed paper, Janice Jackson and Charles

Cochrane of the Scripps Clinic and Ewa Gajewski, Alfred

Fuciarelli, and Miral Dizdaroglu of NIST report on experiments at NIST and Scripps in which calf thymus DNA was exposed to "stimulated" human neutrophils in the presence of iron ions. "We, along with other people,

have found that cells that have

been bombarded with the oxi- dants and have DNA damage,

when cultured and put into mice,

will become malignant," explains

Cochrane. "We now ask, 'What is the connection?' Is it the damaged DNA or something else? So

we're looking at exactly what the oxidants are doing to DNA and

trying then to relate that development to the malignant

transformation." The neutrophils were stimulated

with a tumor promoter, phorbol

myristate acetate (PMA). The

DNA then was separated from the

solution and analyzed using gas

chromatography-mass spectrometry with selected ion monitoring (GC-MS/SIM) to identify and

quantitatively determine both the

altered and unaltered DNA bases

present.

GC-MS/SIM is an extremely sensitive analytic technique capable

of detecting damaged base products at concentrations as low as

10 femtomoles (10 parts per

quadrillion.)

The results show that all four DNA bases are susceptible to neutrophil-induced changes. Six

different base products were de- tected and measured quantitatively, including two which had

been previously identified by

other researchers. The quantitative results suggest, according to the researchers, that guanine is the most susceptible DNA base,

followed by adenine, cytosine,

and thymine. M.B.

24
Laser Cooling Limit Brol(en

How

cold can a gas get? Based on recent experiments at the

National Institute of Standards and Technology, a lot colder than

anyone thought. Careful measurements of the temperature of

"gases" of cooled atoms by a group of physicists from NIST, the

University of Connecticut, and the State University of New York

(SUNY) at Stony Brook have revealed that the lowest temperatures

achieved may be more than 10

times lower than the limit pre- dicted by the generally accepted

model, according to a report in the July 1 1 issue of Physical Review Letters. Extremely low-temperature

gases of free atoms or ions are produced in laboratories by a technique known as "laser cooling," which is about 13 years old as a theory and about 10 years

old in practice.

In laser cooling, a laser beam

shines on an absorbing gas and

(rather against intuition) cools it. It works because the laser is tuned

to a frequency somewhat below a resonance frequency for the atom

of interest. On the average, the atom radiates the light at a higher

frequency, closer to resonance, so it radiates away more energy

than it absorbed. The extra energy comes out of the kinetic, or thermal energy of the atoms, so the gas cools down.

The original idea was proposed

in 1 975 by Theodor Hansch and

Arthur Schawlow of Stanford University and independently by

David Wineland and Hans

Dehmelt of the University of Washington. (Wineland now works at NIST.) Since then physicists have

succeeded in cooling ions and

atoms to within a thousandth of a degree of absolute zero. In one

laser cooling technique, arrays of opposing laser beams have been

"We have a clear and

dramatic violation of

the accepted model."

used to create an "optical

molasses," a region that the free atoms experience as a viscous

medium in which they slow down

and tend to stay confined.

Since about 1977, physicists

have generally accepted that there must be a lower limit to the temperature that can be achieved

by these techniques. The reason

is that random emissions and absorptions of photons by the atoms

causes some heating, which at lower temperatures becomes as

important as the cooling effect. The cooling limit is the temperature at which the cooling and the heating are in equilibrium. For

neutral sodium atoms, that limit had been calculated to be about

240 microkelvins (millionths of a degree above absolute zero.) A

number of research groups

across the country have measured the temperature of laser cooled atoms or ions to be near

their cooling limits. Using a method suggested by

Harold Metcalf of SUNY, the group at NIST measured the temperature of sodium atoms,

laser-cooled in optical molasses,

to be about 45 microkelvins, with an uncertainty of about 20

microkelvins. The researchers were so sur- prised by this result that they

25
Physicist William Phillips with the

laser cooling and trapping apparatus.

used three more temperature

measurement methods to confirm

it before reporting that the cooling

limit had been broken. "Our temperatures are completely inconsistent with the accepted value of the cooling

limit," observes group leader

William Phillips of NIST. "We have

a clear and dramatic violation of the accepted model." At present, says Phillips, the reasons for the

viclation are more-or-less "a mystery," but he offers some lines to explore.

26

"For one thing," Phillips says,

"the model is based on an ideal- ized 2-energy-level atom. Real

atoms like sodium have many

levels.

"In addition, the model makes

other approximations. The prediction of the cooling limit assumes

the laser power is quite low, which is not the case in these ex- periments. Now the theory predicts that as you increase laser power, you would raise the temperature, but perhaps when

you take into account multi-level

Such experiments can

make very accurate

measurements of intrinsic properties of tfie

atoms....

atoms, greater power levels pro- duce lower temperatures.

However, at present no one is even sure what such a theory

would look like."

In theory, the cooling limit also depends on how far the laser frequency is "detuned" from the atomic resonance frequency, ac- cording to Phillips. Theory

teaches that the optimum detuning is about one-half the frequency width of the reso- nance, but the NIST experiments were conducted with lasers tuned

2 and 3 linewidths off resonance. One reason why his group observed results which had gone un- noticed before, says Phillips, is

that they specifically set out to measure how the minimum

temperature changed with detuning, and so looked at detunings

which otherwise might not have

been used. For the detunings

which produced the lowest temperatures, the theory predicts a temperature at least twice the "cooling limit," or about 10 times

higher than the observed

temperature.

An important goal of laser cooling experiments is to create samples of free, isolated atoms or

ions, moving very slowly in a confined region, where they can be

probed by various techniques.

Such experiments can make very accurate measurements of intrinsic properties of the atoms

measurements which in the past

have led to important advances in the theories of quantum mechanics and relativity, among others. Such measurements also form

the basis for the best atomic

clocks. The colder the atoms are, the less their motion contributes

to uncertainties in these measurements. The discovery of cooling below

the "cooling limit" should allow even more accuracy than pre- viously thought possible. But, as

Paul Lett, first author on the re- cently published research paper,

points out: "The atoms are going

so slowly that the best measure- ments may need to be done in the weightless environment of an

orbiting shuttle or space station. Here on Earth our atoms double

their kinetic energy after falling only a few millimeters." M.B.
'h'acing the Sources

of Industrial Emissions

In

an effort to track emissions from coal-fired industrial plants to their

sources, researchers at the National Institute of Standards and Technology and The University of Maryland have developed a technique

that shows promise as a simple and definitive way of tracing smoke

particles. The researchers say the method may be the first one suitable

for tracing fine particles over long distances. Other techniques that use

tracer gases detect only gaseous

components of stack emissions,

not particles.

The NIST/Maryland work, sponsored by the Electric Power Re- search Institute, uses artificially enriched stable isotopes of rare earth elements as "tags" to permit

positive identification of emission

particles near the source or miles away. These isotopes are nontoxic and inexpensive. Several rare earth elements

such as neodymium or samarium

are well suited for the project be- cause they contain as many as seven stable isotopes whose relative abundances are constant in nature. This makes these ele- ments nearly insensitive to contamination from outside sources. Researchers can enrich any of these isotopes (such as neodymium-148) with additional atoms

to create a "signature" that can be easily measured later in the

laboratory. At the plant site, the enriched

rare earth element is dissolved in

a solvent and injected into the stack emission stream in the form

of fine droplets. Researchers

believe the solvent then evaporates immediately and the rare earth particles that are left quickly

bind to emission particles. Once

this binding has occurred and

emissions have entered the en- vironment, particles can be re- covered, analyzed, and traced to

their source. The University of Maryland Department of Chemistry is developing this system for injecting the isotopic material into the stack emissions stream. Sample analysis is being done

in the NIST Center for Analytical

Chemistry by thermal ionization mass spectrometry, a powerful

method that charges atoms in the sample and then separates them

by mass. "We anticipate that tagging will be especially effective in the submicrometer particle range," says W. Robert Kelly, chief NIST scientist on the project. "This is important because these tiny particles

are the ones that travel the

farthest." Because up to five isotopes of a rare earth element can be

tagged differently, a single ele- ment possibly can be used to trace particles simultaneously

from up to five sources. That

would let researchers assess in- dividual emission contributions from several sources at one site. Besides allowing samples to be

traced to their sources, the mass

spectrometric analysis also can measure how much of the tagged

material is present, in essence

gauging the source's environmental impact.

At present, project work has

been confined to determini.,g the tagging technique's feasibility by

in-stack tests at a single coalfired plant site. Project re- searchers now would like to track

the emissions of more than one power plant and to analyze

vegetation samples to investigate

whether emission sources can be

separated. J.H.

27
Helping Industry Find

Substitute CFC's

Somethings are just too good to be true. That seems to be the case

with CFC's—chlorofluorocarbons—now in use. Over the past 50

•years, these CFC's have significantly affected our way of life. They

are used as refrigerants for home refrigerators and freezers, re- frigerated tractor trailers, and automobile air conditioners as well

as insulation in homes and commercial buildings.

But recent evidence has shown

that these chemicals which have

made modern life so comfortable

also can damage the Earth's ozone layer. The threat is so great

that industries worldwide are seeking substitutes. The National

Institute of Standards and Technology is helping in the search

Mark McLinden (left), a chemical engineer, and Graham Morrison, a

physicist, are developing property data for refrigerants that will not harm the ozone layer.

for alternative refrigerants by

developing data on the properties

of likely candidates.

The CFC's currently in use are

nontoxic, nonflammable, inexpensive, odorless, and, most essentially, stable. Stability, however, can be a double-edged sword; once emitted to the atmosphere

CFC's continue to persist. There

is much evidence that the CFC's now being used can break down

the ozone layer which protects

the Earth against harmful levels of

ultraviolet radiation from the sun. An international agreement has

been proposed to reduce current CFC production to 50 percent of 1986 levels before the end of the

century.

Among the CFC's targeted for reduction are trichlorofluoro- methane (R-11 ) and dichlorodi- fluoromethane (R-12). According

to the Chemical Manufacturers

Association, R-1 1 and R-12 ac- count for about 70 percent of all CFC emissions. Both R-1 1 and R- 12 are used as a foaming agent

in making low-density plastics

and foam insulation for buildings,

refrigerated trailers and railroad cars, and home appliances. R-1

also is used in centrifugal chillers

for cooling commercial buildings

and R-12 is the working fluid in commercial and residential re- frigerators and freezers and auto- mobile air conditioners.

Finding Alternatives

While it seems likely that alternatives will be other CFC's, information on most CFC's is meager,

proprietary, and, in some cases,

conflicting or of questionable

quality. But with the recently pro- posed international agreement to phase out R-1 1 and R-12, information on the chemical and physical

properties of other CFC's is vitally needed by industry to evaluate

possible replacements. For the most part, industry is concerned

with developing the manufacturing processes for the new alternatives and determining properties

such as toxicity, flammability, and

materials compatibility needed to

28
make decisions regarding the economics and feasibility of an alternative. NIST's work will build on the Institute's long-standing re- search programs in refrigerants

and refrigeration systems and

thermodynamic properties. It will focus on determining the thermal

properties needed for machinery

design and adaptation. Results of the NIST research will be publicly

available. Researchers in the NIST Centers for Building Technology and

Chemical Engineering are developing fundamental data on

the chemical and physical properties of CFC's and mixtures of CFC's. This data is needed by in- dustry to help evaluate the impact

that likely candidates for replacement refrigerants will have on

equipment. Ideally, industry

would like to have "drop-in" substitutes—chemicals that perform

as the CFC refrigerants now on

the market. If drop-ins cannot be

found, equipment manufacturers

would have to redesign products

and manufacturing operations

and procure new tooling—

process that could cost millions

of dollars. In addition, equipment

still in use would have to be retrofitted or replaced.

Property Measurements

In work being funded by the American Society of Heating, Refrigerating and Air-Conditioning

Engineers, the Environmental Protection Agency, and the U.S. Department of Energy, NIST

researchers are developing property measurements for R-134a

and R-123. These refrigerants seem to be good candidates to replace R-1 2 and R-1 1 . But little information is available on their thermodynamic characteristics which engineers need to evaluate how a refrigerant will perform in equipment. NIST plans to complete the measurements and

make tables and charts containing the information available later

this year.

in addition to developing data

for specific refrigerants, the NIST

researchers are working on a

mathematical model that can be

used to estimate properties from

a small amount of data. The

model will be especially useful in helping to determine how a mixture of CFC's will perform. Infor- mation on mixtures is even more meager than information available on single refrigerants. But mixtures can expand the list of re- placement refrigerants by

mitigating an undesirable property of an otherwise acceptable

compound. For example, the CFC

refrigerant 152a is by itself moderately flammable but it can form

a nonflammable substance when

mixed with R-1 2.

Foam Insulation

Two of the most efficient insulating products used in new building construction today are polyurethane and extruded polystyrene rigid foam insulation; both

contain CFC's. During the foam

manufacturing process, CFC's

either R-1 1 or R-1 2—are used to form gas cells or bubbles. These

cells greatly reduce the amount

of heat transferred through the

material, making it an excellent

insulator.

In a study for the Department of Energy, NIST researchers looked

at the economics of alternative in- sulation materials. Specifically,

they investigated the cost effec- tiveness and potential energy con- sequences of using expanded

polystyrene (EPS) and fiber- glass—neither contains CFC's. They found that both EPS and

fiberglass typically cost less than most CFC-containing foams. But

since they contain air bubbles in- stead of gas bubbles, they do not

insulate as efficiently. Because

more of the material is needed to achieve the same thermal per- formance, there may be an in- crease in cost if walls or roof areas must be expanded to ac- commodate the thicker insulation. To help industry evaluate the thermal performance of new candidates for foam insulation, the re- searchers also are going to build a database of heat flow (thermal

conductivity) measurements for foam insulation currently on the market. Only limited data now are

available. They will measure the thermal conductivity of three CFCcontaining foams—extruded polystyrene (R-1 2), polyisocyanuarate

(R-1 1), and phenolic foam insulation (mixture of R-1 1 1 and

R-1 13)—as well as expanded

polystyrene, which does not contain CFC. As replacement candidates come along, extensive heat

flow measurements will be added

to the database, allowing manufacturers to compare their thermal performance. J.K.
NewPublications

A Summary of the New European

Community Approach to Standards Development

Cooke, P.W., Natl. Bur. Stand. (U.S.), NBSIR 88-3793-1, 13 pages (August

1988). Send a self-addressed mailing

label to: Patrick W. Cooke, Office of Standards Code and Information, A629

Administration BIdg., NIST, Gaithersburg,

MD 20899.

The Commission of the European

Communities (EC) is acting swiftly

to turn the 12-member countries

into a single integrated market of 320 million people by the end of 1992. EC

legislation dealing with standardization is likely to have a profound effect on U.S. exports, predicts this report. The report

recommends U.S. business interests should establish communications with European subsidiaries, distributors, or

their American industry associations to obtain up-to-date information on the development of European directives and

standards. U.S. companies also are urged to seek and take opportunities to comment on, and attempt to influence,

proposed European directives and standards. This report contains a list of EC and

U.S. government contacts for information on various aspects of EC activities re- lated to standardization.

The ABC's of Certification

Activities in the United States

Breitenberg, M.A., Natl. Bur. Stand.

(U.S.), NBSIR 88-3821, 28 pages (July

1988). Order by sending a self- addressed mailing label to Maureen A. Breitenberg, A629 Administration BIdg.,

NIST, Gaithersburg, MD 20899.

Certification programs, considered

a vital link between product stand- ards and actual products, have

significant impact on the marketplace.

This publication describes the different types of programs or schemes used to produce written assurance that a product

or service conforms to a standard or

specification. A sequel to The ABC's of Standards-Related Activities in tlie United States (1987), the new report pro- vides a further introduction to certification

for those not familiar with this important standards-related activity. Included are descriptions of product quality; self- certification; third-party certification; federal, state, international, and regional

programs; choice of standards; certification methodology; and certification marks. The report also addresses some

of the potential problems with certification programs.

Comparison of Direct Digital

Control and Pneumatic Control

Systems in a Large Office

Building

Bushby, S.T. and Kelly, G.E., Natl. Bur. Stand. (U.S.), NBSIR 88-3739, 55 pages

(March 1988). Order by stock no. PB #88-

215470/AS from NTIS, $14.95 prepaid.

In

a comparison of two energy management and control systems (EMCS),

NIST researchers found the microprocessor-based EMCS performed as

well as, and in many cases better than and consumed less energy than, the pneumatic control system. The microprocessor-based system was developed

by NIST and constructed of "off-the- shelf" components. The communication

and control software also was written in- house. The system was installed in the NIST 11-story Administration Building

along with the in-place pneumatic sys- tem. Both were monitored for a year. One

advantage of the microprocessor system

IS ease of resetting and maintaining operating schedules. A problem with the pneumatic system is that the tuning of the system "drifted" with time and was

sensitive to changes made during routine

maintenance. The microprocessor-based

EMCS gives more information about the performance of the system allowing

problems to be discovered earlier and

providing information for diagnosing a problem.

Alaskan Marine Mammal Tissue

Archival Project: A Project

Description Including Collection

Protocols

Becker, P.R., Wise, S.A., Koster, B.J., et

al., Natl. Bur. Stand. (U.S.), NBSIR 88- 3750, 53 pages (March 1988). Order

from Stephen Wise, Al 13 Chemistry

BIdg., NIST, Gaithersburg, MD 20899.

In

an effort to pinpoint the environmental effects of industrial activities such

as offshore oil exploration and mineral

extraction in Alaska, NIST has joined forces with the National Oceanic and At- mospheric Administration (NOAA) to study the tissues of a variety of Alaskan

marine mammals. The fatty tissues of these mammals are excellent accumulators of contaminants that upon chemical

analysis provide accurate pictures of pollutant levels at a given time and

place. Because these animals are top

predators in the marine environment,

scientists also can examine the effects of pollution on the marine food chain. Re- searchers in the NIST/NOAA program

are using the National Biomonitoring

Specimen Bank, housed at NIST headquarters in Gaithersburg, Md., for long- term storage of the samples. Their goal is to create an archive of mammal tissue collected over several years that would

indicate a baseline contaminant level against which future measurements can be compared. This report describes

detailed procedures for collection, analysis, and storage of samples.

30
Fire Research Publications, 1987

Jason, N.H., Natl. Bur. Stand. (U.S.), NBSIR 88-3758, 70 pages (April 1988).

Order by stock no. PB #88-19961 1 from

NTIS, $14.95 prepaid.

Interested in the combustion toxicity of various plastics? cigarette fire-safety?

sprinklers? smoke control? soot formation? Tfie NIST Center for Fire Research

last year issued publications and articles on these topics and many others, all of which are compiled in this bibliography.

NIST conducts research on how fires

start and spread and how they can be

detected and suppressed. This research

leads to realistic material test methods,

cost-effective fire safety design

concepts, and new methods of fire control and extinguishment.

Directory of Federal Government

Certification Programs

Breitenberg, M., editor, Natl. Bur. Stand.

(U.S.) NBS Spec. Pub. 739, 229 pages

(April 1988). Order by stock no. 003-003-

02852-5 from GPO, $12 prepaid.

This IS a guide for manufacturers,

distributors, state and local govern- ment officials, importers, con- sumers, and others concerned with standards and procedures used in federal certification programs. It contains in- formation on manufactured products,

agricultural commodities, medical ser- vices—devices and drugs, defense pro- curement items, transportation, and the

voluntary inspection and uniform grading

of such food Items as dairy products,

meats, and produce. Each entry describes the scope and nature of the pro- gram, lists the testing and inspection

practices, standards used, methods of identification and enforcement, reciprocal recognition or acceptance of certification, and a contact point in the federal agency. The updated directory is a joint effort by NIST and the U.S. Department

of Agriculture.

GATT Standards Code Activities

of the National Bureau of

Standards 1987

Overman, J.R., Natl. Bur. Stand. (U.S.), NBSIR 88-3747, 31 pages (March 1988).

Order from the Office of Standards Code

and Information, A629 Administration

BIdg., NIST, Gaithersburg, MD 20899.

This annual report describes NIST's

role over the past year as the official U.S. GATT (General Agreement on Tariffs and Trade) inquiry point

for information on standards and certification activities that might significantly af- fect U.S. trade. The NIST effort included

coordinating comments on proposed for- eign regulations, translating of foreign

texts, and operating the GATT "hotline" (301/975-4041 , not toll free) that provides

the latest information on foreign notifica- tions from the GATT Secretariat in Geneva, Switzerland. The 1987 highlights were participation in the GATT

Standards Code meeting on information exchange and the ISONET (International

Organization for Standardization Information Network) workshop on international trade; publication of an introduction to standardization, certification, and laboratory accreditation; and background re- search for the Canadian Free Trade

Agreement.

The Journal of Research of the

National Bureau of Standards

Kessler, K.G., chief editor, Natl. Bur. Stand. (U.S.), Vol. 93, No. 3, 525 pages

(May-June 1988). Order by stock no. 703- 027-00022-9 from GPO, $3 prepaid.

The proceedings of a 1987 symposium, "Accuracy in Trace Analysis—Accomplishments, Goals,

Challenges," have been reprinted in this special edition of the journal. The 4-day

event at NIST covered topics such as the

history of trace analysis, robotics in the chemistry lab, measuring vitamins in foods, and the use of microwaves to dissolve samples. The proceedings consist

of nearly 140 technical reports.

NBS Standard Reference

Materials Catalog 1988-89

Seward, R.W., editor, Natl. Bur. Stand.

(U.S.), NBS Spec. Pub. 260, 148 pages

(January 1988). Order from the Office of Standard Reference Materials, B31

Chemistry BIdg., NIST, Gaithersburg, MD

20899, 301/975-OSRM (6776).

Nearly 1,000 Standard Reference

Materials (SRM's) available from

NIST are listed in this catalog. The

SRM's, certified for specific chemical

and physical properties, include ce- ments, ores, metals, glass, plastics, food,

and environmental and clinical items. The expanded list of nutrition and health standards includes materials to calibrate instruments to detect marijuana in a human urine sample (SRM 1507) and to improve the precision of tests for ele- vated levels of the enzyme aspartate

aminotransferase (AST) to detect heart at- tacks (SRM 8430). Two new micro-length

standards also are listed. The first commercial space-made product, 10-Micro- meter Polystyrene Spheres (SRM 1965),

is available on a glass slide to calibrate microscopes. The second commercial

space-made product, 30 Micrometer

Polystyrene Spheres (SRM 1961), is a new measurement standard for powder

manufacturers. Also available is a series

of seven individual low-alloy steels widely

used in industry (SRM's 1761-1767).

Ordering Information

To order publications from NTIS, send re- quest with payment to: National Technical Information Service, Springfield, VA

22161. Publications can be ordered from

GPO by mailing the order with payment

to Superintendent of Documents, U.S. Government Printing Office, Washington,

DC 20402.

3^
Conference

Calendar

I April 3-7, 1989

6th International Conference on

High Temperatures: Chemistry of

Inorganic Materials

NIST, Gaithersburg, MD

This meeting will bring together experts

in the field of high-temperature materials

to discuss the latest scientific and technical developments. Both plenary and

selected contributed papers will be pre- sented and published subsequent to the meeting. Academic, industrial, and

government researchers worldwide

having an interest in high-temperature

processing, performance, and properties

of inorganic materials will participate in the meeting. Organized under the joint sponsorship of the International Union of Pure and Applied Chemistry and NIST. Contact: John W. Hastie, B106 Materials

Building, NIST, Gaithersburg, MD 20899,

301/975-5754.

mpril 17-21, 1989

Nuclear Analytical Methods in the

Life Sciences

NIST, Gaithersburg, MD

Nuclear analytical methods, in particular nuclear activation techniques, constitute an important group of methods of chemical and physical-chemical analysis.

Papers will be presented in oral and

poster sessions on the following topics: new and emerging methodology, activation techniques, quality assurance, comparison of activation analysis with other methods, and applications of nuclear techniques in biology, medicine, bi- otechnology, agriculture, and nutrition as

well as in public and environmental

health. This international conference is or- ganized by NIST, in cooperation with the

International Atomic Energy Agency. It is cosponsored by the American Nuclear

32

Society, the U.S. Department of Energy,

and the Food and Drug Administration. Contact: Rolf Zeisler, B108 Reactor Building, NIST, Gaithersburg, MD 20899,

301/975-6290.

April 26-28, 1989

Fifty Years With Nuclear Fission

NIST, Gaithersburg, MD

Fifty years with nuclear fission will be

celebrated with a conference at NIST

and the National Academy of Sciences.

Chaired by G.T. Seaborg and E. Segre,

the first general session, to be held at NAS, will feature invited talks devoted to a historical account of progress in the

field given by leading contributors from

the United States and abroad. The sec- ond and third days of the conference, to be held at NIST, will feature papers

covering such topics as: fission theory, in- strumentation, fission applied data, astro- physical and space applications, fission by-products in biology and medicine, in- dustrial fission by-product applications, reactor design and development, and

peaceful uses of fission technology.

Sponsored by NIST and the American

Nuclear Society, and cosponsored by

the American Physical Society Division of Nuclear Physics and the American

Chemical Society Division of Nuclear

Chemistry and Technology. Contact Oren A. Wasson, B109 Radiation Physics

Building, NIST, Gaithersburg, MD 20899,

301/975-5567 (FTS 879-5567).

May 4-5, 1989

9th Conference on Roofing

Technology

NIST, Gaithersburg, MD

NIST and the National Roofing Contractors Association have joined to sponsor

conferences on roofing technology on a

biennial basis since 1969. The theme of the 9th conference is "Putting Roofing

Technology to Work." Topics that will be

discussed include thermal analysis for membrane characterization, field testing

and the effect of surface contamination on adhesive-bonded seams, compatibility of insulations and membranes,

vapor retarders, thermal bridging,

planned maintenance, and new developments in coatings. Sponsored by the National Roofing Contractors Association

and NIST. Contact: Walt Rossiter, B348

Building Research Building, NIST,

Gaithersburg, MD 20899, 301/975-6719.

June 7-9, 1989

Second International Conference

on Hot Isostatic Pressing (HIP)

Theory and Applications

NIST, Gaithersburg, MD

During the last 15 years hot isostatic pressing (HIP) has proved to be a versatile technique for the manufacture of advanced products and to increase the performance of components. Significant

advances are occurring in the modeling

of the densification process, in the development of more versatile HIP units, and in the application of HIP technology

to new types of materials. The goal of this conference is to promote a wider aware- ness of advances which have occurred

since the previous conference in Lulea,

Sweden, in the theories and application

of HIP, and to stimulate discussions of these advances and of the future directions for HIP technology. Sponsored by

NIST. Contact: Robert Schaefer, A153

Materials Building, NIST, Gaithersburg,

MD 20899, 301/975-6176.

-- U.S. GOVERNMENT PRINTING OFFICE 1988 - 242-311 - 814/92587

U.S. DEPARTMENT OF COMMERCE

National Institute of Standards and Technology

Gaithersburg, MD 20899

OFFICIAL BUSINESS

Penalty for Private Use, $300

BULK RATE

POSTAGES FEES PAID NIST

PERMIT No G195