INquiry Science and Technology at the Ames Laboratory 2002

A U.S. Department of Energy laboratory operated by Iowa State University

Science and Technology at the Ames Laboratory

New paradigm in sensor technology

Organic chemistry without solvents

Seeking a science trifecta

New paradigm in sensor technology

Organic chemistry without solvents

Seeking a science trifecta
2 Sensible Sensors . . . Saren Johnston

An Ames Laboratory basic research effort to study the photophysics of organic light-emitting devices may lead to a

new standard in sensor technology.

4 Shaken, Not Stirred . . . Kerry Gibson

Traditionally, solvents have been used to break down organic materials in order to carry out reactions. But a group of

Ames Laboratory researchers has come up with a new method that could really shake up the field of organic chemistry.

6 Cleaning Up an Environmental Legacy . . . Mary Jo Glanville

Ames Laboratory is coordinating efforts to share information and develop tools and techniques that will facilitate

cleanup of nuclear waste generated by weapons production during the Cold War.

8 A Sure Bet . . . Steve Karsjen

Forensics, biorenewables and catalysis – these three new Ames Laboratory initiatives are providing opportunities

for research and researcher partnerships.

12 Inquiries at the Interface . . . Saren Johnston

Researchers are looking at certain microscopic properties that exist on the borderline – where liquid meets solid –

during the solidfication of metals. What they learn in these fundamental studies may one day make it possible to

tailor microstructural development.

14 Break-through Booster . . . Kerry Gibson

Like marathoners, researchers also can hit the wall. But an Ames Laboratory initiative uses the power of the

Materials Preparation Center and the Lab’s expertise to help materials scientists get projects back on track.

17 Atomic Fingerprints . . . Saren Johnston

The development of innovative solid state nuclear magnetic resonance techniques is leading to new insights about

the structure of materials.

22 “Lite” Done Right . . . Saren Johnston

Tidy and compact, a new parallel library, MP_Lite, promises to boost the performance of parallel computers and do

so in a user-friendly way.

INtouch 16, 20, 21, 24

Look in on some more Ames Lab success stories.

Contents

(front cover) This brilliant blue organic light-emitting device was developed by Joseph Shinar and his Ames

Laboratory research group. The versatile, low-cost OLEDs are used as light sources for the fluorescent sensors

made by Shinar’s group and their collaborators, Raoul Kopelman’s group of the University of Michigan, Ann

Arbor. Their combined research efforts have resulted in the creation of an integrated OLED/optical chemical

sensor in which the detector and the light source that excites the fluorescence are integrated with the sensor

films. (see story page 2)

(back cover) Small vials containing fatty acid conversion product are bagged for identification purposes in

the reactor lab. The liquid in these vials will be analyzed for dibasic and monobasic acids. (see story page 8)
from the Director

I can’t imagine that anyone in the U. S. faced with writing an

annual summary letter this year would not begin with an

observation that this has been an extremely difficult year for our

nation. However phrased, it will be an understatement. The

events of September 11th and our forthcoming heightened

awareness of the international terrorist movement have changed

the way we approach many aspects of our daily lives and how we

think about life in general.

The plunge of the stock market and the corresponding

diminution of our individual retirement holdings have caused us

to cease dreaming of a lakeside retirement home, and to view

“like a cross to a vampire” the letters arriving with quarterly reports of the status of these funds. Throughout the year, it has

been a challenge not to be filled with anger at the corporate executives who, through deceit, filled their pockets at the expense

of their own employees and stockholders, and also a challenge not to be filled with concern that Iowa’s budget woes were

addressed by disappointing reductions in funding for higher education.

Was there anything good about this year? Well yes, as a matter of fact, a lot of good things happened in the Ames Laboratory

this year. Particularly timely was the opening of our Midwest Forensics Resource Center that is putting the world-renowned

analytical capabilities of the Lab to work on problems in forensic science, especially those that face our rural crime

investigation units.

Our scientists continued to receive prestigious awards both for fundamental and applied research. Indeed, watching our

basic scientific discoveries be translated into practical uses is one of the true joys of my job. That’s why I’m standing in a

soybean field on a farm in central Iowa in the above photograph. Ames Laboratory’s new Biorenewable Resources

Consortium is heavily directed toward Iowa’s abundant agricultural resources, such as soybeans. In this issue of Inquiry,

you can read about how our BRC will turn ordinary crops into high-value products that could enhance economic

development in rural states, like Iowa.

Our cover story features a photo of an organic light-emitting device developed by Ames Laboratory physicist Joseph Shinar.

This unique light source serves as a compact, versatile and cost-effective alternative to expensive laser systems used to analyze

living cells and organisms, and biological compounds.

In the area of “green chemistry,” a team of Ames Laboratory scientists led by Vitalij Pecharsky has developed a revolutionary

process to combine organic materials in solid state without the use of solvents. The discovery has the potential to dramatically

improve our world by eliminating environmentally harmful solvents, such as benzene, used in chemical processes to produce

millions of consumer and industrial products.

Physicist Bruce Thompson’s expertise in the development of fundamental nondestructive evaluation techniques is being

utilized by the Department of Energy in an important project assessing the structural integrity of aging underground storage

tanks containing radioactive liquid wastes.

As always, solving our nation’s energy problems remains key to Ames Laboratory’s mission. The research efforts I’ve

mentioned are just a few examples of how we’ve supported that mission in 2002. You will read about these and other Ames

Laboratory accomplishments in the following pages of this year’s Inquiry, and I’m

confident you will agree that, yes, there were some very good things that happened

in this past year. As always, we take pride in our accomplishments and look

forward to the challenges ahead.

Inquiry is published annually by the Ames Laboratory

Office of Public Affairs. Iowa State University

operates the Laboratory for the U.S. Department of

Energy under contract W-7405-Eng-82. Located on

the ISU campus, the Ames Laboratory is a member

of the university’s Institute for Physical Research and

Technology, a network of research and technologytransfer centers and industrial-outreach programs.

Editor

Steve Karsjen

Managing Editor

Saren Johnston

Art Director

Patrick Herteen

Photographer

Dennis Sailsbury

Copyright 2002 by Ames Laboratory.

All rights reserved. For additional

information about Ames Laboratory

or topics covered in this publication,

please contact:

Editor, Inquiry

Ames Laboratory

111 TASF

Ames, Iowa 50011-3020

(515) 294-9557

www.external.ameslab.gov

2002 1 INquiry
Sensible Sensors

We can envision the whole thing to

be about the size of a silver dollar.

Ultimately, it should have extremely

wide-ranging applications,” says

Joseph Shinar.

The Ames Laboratory senior physicist

is talking about the novel, fluorescencebased chemical sensor he developed in

collaboration with chemist Raoul

Kopelman from the University of

Michigan, Ann Arbor. The new sensor

is smaller, less expensive and more

versatile than existing technology of its

kind, making it a potentially perfect fit

for monitoring oxygen, inorganic gases,

volatile organic compounds,

biochemical compounds and biological

organisms. Within the field of

molecular diagnostics for biomedical

and biochemical research, the sensor

could be used for point-of-care medical

testing, high-throughput drug

discovery, and detection of pathogens

and other warfare agents.

Ideally integrated

The new sensor grew out of a basic

research effort by Shinar and his Ames

Lab research group to study the

photophysics of luminescent organic

thin films and organic light-emitting

devices, or OLEDs, (those that

luminesce, or emit light, when a

voltage is applied). The University of

Michigan researchers, led by

Kopelman, were interested in

developing fluorescent sensors, so the

two groups joined forces to drive the

invention of an integrated OLED/

optical chemical sensor.

Shinar says the sensor had its

beginning with a simple idea put forth

by postdoctoral fellow Jon Aylott, who

was working with Kopelman. “The

invention started with just some

scribbled notes about using organic

light-emitting devices as light sources

for fluorescent sensors,” Shinar recalls.

“When the idea was first brought up,

my own response was, ‘Well, there’s

nothing here. It’s so obvious – of course

you can excite a fluorescent sensor with

an OLED.’ You can, but it hadn’t been

done yet. And the beautiful thing is that

you can integrate the two.”

Shinar explains that the integration

and miniaturization of fluorescencebased sensors is highly desirable

because it is the first step toward the

development of fluorescence-based

sensor arrays that could be used for

analysis of living cells and organisms,

and biochemical compounds. In

general, fluorescence-based chemical

sensing devices include three

components: a light source that

excites the sensing element, the

sensing element that produces the

fluorescence (usually a fluorescent dye

that is used to tag the sample under

investigation), and a photodetector

that responds to the fluorescence of

the sensor. Conventional sensors use

lasers or inorganic light-emitting

devices as light sources, but they

present problems. Not only are they

expensive, they are also bulky and

cannot be integrated with the other

sensor components.

The beauty of a new chemical sensor lies in its simplicity by Saren Johnston

2002 2 INquiry
Stylishly simple

Shinar’s and Kopelman’s OLED/

optical chemical sensor is unique in the

simplicity of integration of the detector

and the OLED light source that excites

the fluorescence. “This is a real

advantage,” says Shinar. “With this

kind of geometry, called ‘back

detection,’ we should be able to use the

sensor for in vivo biology applications.”

(In vivo refers to occurring within the

living organism.)

Explaining the back-detection design,

Shinar says, “Let’s say you have some

solution – blood, urine, whatever – on a

glass substrate. The solution has lots of

compounds in it that you want to

detect. Your sensor is in contact with

the biological solution on the substrate,

and your OLED light source is behind

the substrate. It’s like a sandwich:

sample solution, sensor, substrate,

OLED.” Powered by a miniature

battery, the OLED light source excites

the sensor, which fluoresces. When the

sensor detects the compound of interest

in the sample solution, its fluorescence

changes, and the change is picked up

Senior physicist Joseph Shinar and

graduate assistant Lijuan Zou watch as

graduate assistant Kwang-Ohk Cheon

adjusts an organic light-emitting device,

or OLED (see cover photo), prior to

testing its brilliance.

Schematic of the

proposed integrated

fluorescence-based, high-density

chemical sensor array. The detector

can be a charge-coupled device or set of

photodiodes that collect the light signal and

transmit the resulting electrical signal to the

processing unit. Zoom-in: Cross section of the

integrated sensing device.

by a photodetector positioned behind

the OLED.

Shinar says the integration of the

OLED light source, fluorescent sensor

and detector makes the whole device a

lot more compact and should also

permit the development of an array of

fluorescent sensors to be driven by an

array of OLEDs. Describing an

envisioned array, he says, “You could

have a square with the corners formed

from four OLED pixels that would be

exciting the sensor in front of them.

The light from the fluorescent sensor

would come back through the area

between the OLED pixels. Each pixel

could be 10 microns, so this whole thing

could easily be a square of 40 microns

by 40 microns – that’s your sensor.”

Prototype and

promising product

Early in 2001, Shinar and his

collaborators successfully demonstrated

an oxygen sensor prototype in which

the OLED was integrated with the

oxygen sensor film. “The results were

excellent,” he says. “The response of

the sensor to oxygen was very fast.”

Shinar says they used front detection

instead of back detection with the

oxygen sensor prototype. Now their

goal is to demonstrate the backdetection capability. In addition, he

anticipates that the Ames Labratory and

University of Michigan research teams

will be able to develop a prototype for a

glucose sensor in the near future. “The

recipe is there, but we’re wrestling with

the stability of the glucose enzyme,

which has a drastic effect on the uptake

of oxygen by glucose,” he says.

The integrated OLED/optical

chemical sensor has tested so well that

Shinar is investigating the possibility of

starting a business to produce them.

“We’d be making the whole sensor

device,” he says. “It would include

packaging the OLED with the sensor,

filters, photodetector, power supply and

the readout mechanism, which would

be digital, either on a liquid crystal

display or a regular light-emitting diode

– or, it could be an OLED readout.”

Because most of the components for

the sensor are so cheap, Shinar says

almost the whole package could be

disposable. The only component that

wouldn’t be disposable, at least in the

foreseeable future, would be the

photodetector. “If the sensor is

produced in mass volume, I could easily

envision its price to be less than $50 for

the whole thing,” he says. “That’s just a

guess based on having the photodetector

be less expensive, because everything

else should be really in the pennies.”

The versatility, flexibility and costeffectiveness of OLEDs offer excellent

opportunities for developing OLED/

optical chemical sensor arrays and highdensity microarrays. Such systems

would be able to discriminate between

multiple compounds in complex

biological samples, such as blood, urine,

saliva or airborne particles, creating

what Shinar describes as a very

economical, compact and practical

optoelectronic “nose” or “tongue,”

suitable for in vivo measurements.

“The big excitement is that a whole

new paradigm in sensor technology could

emerge from this work – from this basic

idea of just integrating the very low-cost

OLED light source with the fluorescent

sensor,” says Shinar. “The integration is

really the big step forward.” ◆

For more information:

Joseph Shinar, (515) 294-8706

shinar@ameslab.gov

Research funded by:

DOE Office of Basic Energy Sciences,

Materials Science and

Engineering Division

2002 3 INquiry
As often happens in science, a group of Ames Laboratory

researchers didn’t set out to discover a revolutionary process

to create organic compounds. Study in another area

prompted a question and a “let’s-give-it-a-try” response.

As a result, their findings that organic compounds can be

formed in solid state marks a major advance in both materials

science and chemistry where the two fields overlap. The

discovery means that environmentally harmful solvents, such

as benzene, dichloromethane and others, could be removed

from many of the chemical processes used to produce

thousands of consumer and industrial products. The initial

cost-savings for the solvents alone would be substantial, but

when combined with the reduction or elimination of disposal

costs for the spent solvents and minimization of chemical

waste streams, the overall benefits could be enormous.

Balls replace solvents

The discovery centers on ballmilling, a process routinely

used to alloy various metals. Simply stated, the component

metals to be alloyed are placed inside a hardened steel vial

along with balls of varying sizes. The sealed vial is then

shaken vigorously for extended periods of time. Mechanical

energy going into the system is transferred to the materials,

eventually combining them at the molecular level to form the

new alloy.

“We started several years ago trying to find suitable

materials for hydrogen storage,” says Ames Laboratory senior

scientist Vitalij Pecharsky. “As part of that project, we looked

into modification of the structure of materials using

mechanical alloying. Then we started to look into different

classes of materials that were not related to that project, and it

took off from there.”

Organic materials have very different crystal structures, so

they don’t readily combine in solid state when mixed together;

typically they must be dissolved to break down their

crystallinity. Once the materials are in solution, they can be

combined and the chemical reaction takes place. The

resulting product is then separated out.

Given their expertise in alloying various materials,

Pecharsky and a fellow researcher, Ames Lab associate scientist

Viktor Balema, decided to explore if ball milling could take the

place of solvents in carrying out organic chemical reactions in

solid state. Shaking up the materials was easy. The problem

was how to tell whether the reaction had indeed taken place

during mechanical processing of the solids.

One major tool typically used to study a material’s crystal

structure is diffraction analysis. X-rays - short wavelength

electromagnetic radiation - shone through a material will form

a specific diffraction pattern dependent on the crystal

structure of the material. This usually allows researchers to

identify the solid material based on the spectrum displayed.

 “But since our experimental approach is mechanochemical, it

reduces the particles to very small size and induces plenty of

strain and stress,” Pecharsky says. “Essentially, what we end up

with is either poorly crystalline materials or materials that aren’t

crystalline at all, and diffraction techniques are nearly useless.”

NMR tracks reactions

For answers, Pecharsky and Balema turned to Ames Lab

colleagues, physicist Marek Pruski and chemist Jerzy Wiench,

leading experts in solid state nuclear magnetic resonance

spectroscopy, known as NMR. In NMR, a strong magnetic

Creating organic compounds

without solvents by Kerry Gibson

Viktor Balema loads material into a ball-mill vial in a

glove box to prevent possible contamination of the sample

prior to processing.

A close-up shows a hardened steel vial and the balls used to

process the materials. The vial fits in the cage of the mill,

which operates similar to a paint shaker at a paint store.

2002 4 INquiry
field is used to split the energy levels of the atomic nuclei in

the material being studied.

“The transition frequency that corresponds to the splitting

identifies the nucleus and the local environment in which the

given nucleus finds itself,” Pruski says. “In other words, by

monitoring the transition frequency, we can fingerprint the

specific material.”

NMR proved to be perfect for verifying the experimental

results. Using materials that produce well-known and welldocumented reactions when carried out in solution, Balema

and Pecharsky combined these prototype materials in the ball

mill and took the resulting products to Pruski and Wiench.

With a limited number of possible end products, they were

able to quickly match the NMR of the experimental products

with commercially prepared samples.

“This was almost born for NMR,” Pruski says. “In principle,

they have a pretty good idea of what to expect, and we can tell

them right away if the expectations are met or not. It doesn’t

take a lot of handwaving to explain the results. If they had no

idea of what the reaction would produce, then we’d have to

spend more time pinpointing what it was.” (To find out more

about solid state NMR spectroscopy, turn to “Atomic

Fingerprints,” on page 17.)

 “The spectra that we collected indicates that the processes

do occur in solid state,” Wiench says, “ruling out the

possibility that heat generated during processing melts the

materials, permitting the reaction to take place in a liquid

state.” Another advantage is that NMR testing is nondestructive and doesn’t require any prior or further processing

of the material. According to Wiench, this helps eliminate

any chance that other factors might influence the reaction.

High yields, one pot

Not everything the team ran through the ball mill was a

success, but nearly all of the discovered transformations

previously performed exclusively in solution were found to be

exceptionally efficient and selective in the solid state. “I

would never have believed that solvents could be excluded

from all these reactions if I hadn’t done it myself,” says

Balema, adding that milling times varied from one hour to 25

hours, depending upon the reaction being examined.

Vitalij Pecharsky holds a ball-milling vial used to process

materials. The materials and steel balls are placed in the mill

and vigorously shaken for extended periods of time.

Another valuable discovery is that the reactions can be

carried out consecutively, or as “one-pot” processes, when

components required for performing a reaction in stages are

ball-milled together in the same vial. “Remarkably, a ‘one-pot,’

Wittig-type reaction between phosphines, organic halogenides,

aldehydes or ketones, and a base is impossible in a solution,

but it has been successfully carried out in a mill without a

solvent,” Pecharsky says.

To date, the group has operated on a shoestring budget,

borrowing research time to carrying out the testing. Materials

costs have been minimal, according to Pecharsky, and the

testing has used existing equipment.

“If we were to go into some more adventuresome

experiments, for example to elucidate some of the reaction

mechanisms, that takes considerably more effort,” Pruski says.

“We would need to invest more time in experiments and

money in special accessories. We’ve been able to work

around those problems up to now.”

Though they only published their findings in the June issue

of the Journal of the American Chemical Society, Pecharsky

indicates that their work has already been cited by another

group looking into mechanochemistry.

“It’s different work and a different reaction,” he says, “but

it’s all mechanochemistry.” They were also successful in

carrying out organic reactions in solid state with quite high

yields. “Now that we’ve shown that it can be done without

solution, maybe mainstream organic chemists will try it - and

most likely succeed, too, which is good. That’s how science is

done these days. You can’t do it alone,” says Pecharsky.

Echoing that sentiment, Pruski says the Ames Laboratory

effort is truly a multidisciplinary collaboration. “Even though

we’re in different programs, it’s been a good symbiotic

collaboration on science at a very basic level,” he says. “It’s

the way a national lab ought to function.” ◆

For more information:

Vitalij Pecharsky, (515) 294-8220

vitkp@ameslab.gov

A 5-millimeter rotor containing the sample of interest is

inserted into the magic-angle spinner in one of the solid state

NMR spectroscopy probes.

2002 5 INquiry
Ames Laboratory is playing a key role

in a U.S. Department of Energy Office

of Science and Technology project to

address the environmental legacy left

by the production of nuclear weapons

during the Cold War.

This legacy includes millions of

gallons of radioactive liquid waste

stored in 259 huge underground tanks

at five DOE facilities. The tank farms

are located throughout the United

States, with 177 tanks at the Hanford

site in Washington, 51 at the Savannah

River site in South Carolina, 40 at the

Oak Ridge Reservation in Tennessee,

11 at the Idaho National Engineering

and Environmental Laboratory in

Idaho, and two at the West Valley

Demonstration Project in New York.

Many of the tanks, which were built

between the 1940s and 1980s, have

reached or exceeded their original

design life. A number of the tanks are

already known to have leaked and as

they have aged, concern has increased

about additional leakage or collapse.

While work is underway to convert the

waste into a form better suited for

permanent storage, conversion and

cleanup is a long-term process.

Assessing Tank Integrity

The five sites, each with unique tankmanagement issues due to variations in

climate, geography and tank

construction, are at various stages in

the conversion process. As a result,

many of these tanks must continue to

store hazardous waste. Assessing their

structural integrity to determine if

corrosion is occurring or cracks are

developing is essential to protect

people and the environment.

The DOE formed a structural integrity

panel in the early 1990s to begin the

process of assessing the tanks. The

panel gathered extensive information at

each of the sites and held 18 workshops

At the Hanford Site in Washington,

177 radioactive waste storage tanks

were built between 1943 and 1985.

This is a double-shell tank which

contains two carbon-steel liners

along the walls and floor and a

single steel dome liner. It is

enclosed within an outer shell of

reinforced concrete. (Photo

courtesy of DOE’s Pacific Northwest

National Laboratory)

over a six-year period to examine the

issues and concerns. Bruce Thompson,

director of Ames Labratory’s

Nondestructive Evaluation Program,

served as the panel’s ultrasonics expert.

In 1997, the panel issued its technical

report, “Guidelines for Development of

Structural Integrity Program for DOE

High-Level Waste Storage Tanks.”

Ames Lab and the Iowa State

University Center for Nondestructive

Evaluation have had a continuing role

providing assistance to the DOE in

developing appropriate NDE for these

high-level storage tanks. The linkage

between Ames Lab and the CNDE is

very beneficial, according to

Thompson, who is also CNDE

director. “It means DOE has access to

the capability and expertise within

CNDE and ISU. Because the center

actively works with 20 to 25

sponsoring companies, DOE has a

window to NDE technology that is

being used by a wide range of

industries, such as the aerospace

and power-plant industries. If

you’re dealing with some tough

problems, it’s good to find out how

different industries are approaching

similar issues,” he explains.

The role of Ames Lab moved to a

new level when the DOE’s Tank

Focus Area, or TFA, identified the

development and coordination of new

and improved technologies for tank

integrity assessment as a high priority

in September 2000. Ames Lab is

coordinating and implementing the

project jointly sponsored by the TFA

and the Characterization, Monitoring

and Sensor Technologies, or CMST,

Crosscutting Program of the DOE

Office of Environmental Management.

Sharing Information

The project started with visits to each

site. Mike Terry, TFA; Glenn Bastiaans,

CMST; and Brian Larson and Dave

Rehbein, Ames Lab, collected

information from technical personnel

about tank integrity needs and issues.

The first tank integrity workshop was

held in fall 2000. The specific goals

were to identify significant impediments

that might exist to the safe operation

and management of the storage tanks,

particularly those common to multiple

sites; and to establish groundwork for

collaborative efforts aimed at

eliminating those impediments.

“We talked about what’s going right,

what’s not going well, and what needs

improvement. The DOE Order 435.1,

“Radioactive Waste Management,”

2002 6 INquiry
rose to the top in terms of discussion.

It actually mandates the inspection of

the tanks, but we discovered there

wasn’t a perfectly common

interpretation of how to accomplish

that. So there were benefits of people

talking about what this meant,”

Thompson says.

A second workshop, held fall 2001,

took a more technical focus.

Participants identified some areas

where they needed to compare notes.

Thompson explains, “One of these

areas was the phenomenon called

vapor space corrosion. You might

think corrosion would occur below

the liquid, but there is some evidence

that there has been active corrosion

above the liquid and at the liquid/

vapor interface.”

As a result of this discussion, the

Savannah River group organized a

workshop focusing specifically on this

topic. Kurt Hebert, professor in ISU’s

chemical engineering department, was

one of three expert panelists to hear

presentations about experiences at the

sites and plans for addressing the

concerns. The panel responded to the

plans and made recommendations.

In the area of technical assistance,

three CNDE projects are progressing

well, according to Thompson. One

area of need relates to the length of

time it takes to ultrasonically inspect

the tank walls for corrosion. The size

of the tanks, 70 feet in diameter by 70

feet high, translates to a lot of surface

area. The current ultrasonic

techniques use a tightly focused beam

that has to be scanned over the entire

surface. This is an accurate but

inherently slow process.

New Techniques, Tools

Rehbein, an Ames Lab and CNDE

metallurgist, working in collaboration

with Sonic Sensors of EMAT

Ultrasonics, Inc., has developed a

technique to use as a screening tool.

The electromagnetic acoustic

transducer, or EMAT, inspection

system makes use of guided ultrasonic

waves propagating along the tank

walls to rapidly scan the tank walls

and detect thinning or isolated defects

that would then be the focus of a

detailed inspection. Not only is the

EMAT inspection system faster than

the conventional

system, it doesn’t

require extensive and

expensive surface

preparation.

The technique was

successfully

demonstrated on a

mock-up at the Hanford

site in September 2001.

Now it’s a matter of

locating the resources

for further testing on a

full-scale mock-up and

on a tank. “We have put

a new capability on the

table, and now it’s ready

to evolve to the next

level,” Thompson says.

A second project,

being done in

collaboration with

Pacific Northwest

National Laboratory, is

designed to obtain data

from the tanks’ knuckle

regions. In double-shell

tanks, this is where the

sides and bottoms of the steel inner

wall are joined. This area is subject to

relatively high stresses, but detecting

flaws is complicated because it is very

difficult to access.

PNNL is developing a system to

excite ultrasonic waves in the primary

liner using transducers placed in the

annular region where there is physical

access - between the primary and the

secondary liner. The waves propagate

around the curvature of the knuckle

and find defects near the bottom. The

signals are interpreted based on a

technique known as Tandem Synthetic

Aperture Focusing.

This technique is well established

for measurements on a flat plane, so

the question is, how does it have to be

modified when the waves must go

around bends? Ron Roberts, an Ames

Lab and CNDE physicist, is

developing simulation tools to analyze

the wave propagation phenomena as it

applies to curved geometry. These

tools are designed to provide a means

of enhancing the current approach to

give detailed information on the size

and extent of defects.

The third activity focuses on the

concrete walls and domes that cover

Bruce Thompson displays just a few of the many boxes of

documentation gathered in the 1990s by a panel

reviewing the structural integrities of nuclear waste

underground storage tanks located at five DOE facilities.

some of the tanks. These structures have to

withstand the load of heavy equipment used

to retrieve the wastes. A technique called

direct sequence processing allows a signal to

be injected from outside the tank, propagate

along one of the risers that provide access to

the inside of the tank, couple to the

concrete and propagate through it to

another riser where it can be detected.

Measurement of the arrival time of this

signal would provide information about the

modulus of the concrete, which can be used

to determine if there is degradation. A

workshop to develop recommendations is

being planned.

The challenge of cleaning up the

environmental legacy left by the Cold War is

extremely complex. “We have been

challenged to find the fastest and most costeffective ways to insure the safety of people

and the environment,” says Thompson. “To

accomplish this we must continue to develop

plans and tools to assess the structural

integrity of the tanks and thereby reduce the

risk of collapse and leakage for as long as the

tanks are needed.” ◆

For more information:

Bruce Thompson, (515) 294-7864

Research funded by:

DOE Office of the Deputy Assistant

Secretary for Science and Technology

2002 7 INquiry
In horse racing, a trifecta is achieved by picking three

winners in a row. Ames Laboratory hopes to achieve its

own trifecta of sorts in three new initiatives – one in

forensics, one in biorenewables and a third in catalysis.

And all bets are on a successful outcome.

Midwest Forensics Resource Center

Moving with breakneck speed would be the best way to

characterize the pace of activities associated with Ames

Laboratory’s Midwest Forensics Resource Center, or MFRC.

First, there were goals to write and rewrite in order to

establish the MFRC at the Lab and Iowa State University.

Then there was the rural law enforcement workshop to plan

and hold, which was followed by the annual crime

laboratory directors’ meeting, which included an add-on

meeting to discuss preparedness for agro-bio-emergencies.

At the same time these projects were being undertaken,

David Baldwin, director of the MFRC and Ames Lab

program director of Environmental and Protection Sciences,

was assembling the draft of the research “call for proposals”

for projects to be funded through the MFRC. Successful

proposals will receive approximately $55,000 in one-year

funding. Final approval of the draft comes next, followed

by funding of selected research proposals. All in all, it’s

been an exhaustive first phase for this Ames Laboratory

initiative, but according to Baldwin, the pace was necessary

for the MFRC to position itself to meet the growing demand

for forensic analyses in areas ranging from counterterrorism to crime-scene and DNA analysis. “We’ve tried

very hard to be on the edge and ready to go,” says Baldwin.

“We simply don’t want to lose our audience at this point.”

This audience of MFRC collaborators includes several

high-level government agencies, including the Bureau of

Alcohol, Tobacco and Firearms; the FBI; the Department of

Justice’s National Institute of Justice; the National Terrorism

Preparedness Institute; and the Department of Energy. In

addition, the MFRC is partnering with crime lab officials

from nine Midwestern states, including North Dakota,

South Dakota, Nebraska, Kansas, Missouri, Wisconsin,

Minnesota, Iowa, and more recently Illinois. Other partners

include Iowa State University and ISU’s Institute for

Physical Research and Technology.

The MFRC got a major boost in January 2002 when U.S.

Rep. Tom Latham announced financial support for the

center. The $3 million in federal funding was the successful

ending to a long story for Ames Lab Director Tom Barton,

who years earlier had begun discussing establishing the

MFRC with Randy Murch, then deputy director of the FBI

Laboratory. Those conversations were held in the cafeteria

of the J. Edgar Hoover building in Washington, D.C. “We

talked about the problems facing the nation’s crime labs –

needs and obstacles,” says Barton, “and how Ames Lab and

Iowa State University could partner to solve them.”

Those early discussions eventually led to a variety of

research projects being funded by the FBI. Projects ranged

from a type of quick-response bioterrorism database (a joint

venture between the Ames Lab and ISU’s Veterinary

Diagnostic Laboratory) that includes information for labs on

veterinary response to livestock pathogens to a fingerprint

chamber, or glove box, that detects latent fingerprints on

things like cans, guns, even plastic bags. The very first

glove box is housed in the Iowa Division of Criminal

Investigation’s Criminalistics Laboratory in Des Moines,

Iowa. A second glove box is being used by experts in the

crime lab of the Story County Sheriff’s Department in

Nevada, Iowa. Rural law-enforcement agencies with limited

budgets, such as the one in Story County, are considered

prime benefactors of the research expertise developed by

MFRC scientists says a grateful Story County Sheriff Paul

Fitzgerald. “The glove box is certainly something that’s

going to advance our ability to do research and to train and

educate rural law-enforcement officers in forensics,”

Fitzgerald adds.

Other MFRC research efforts have included projects to

restore obliterated serial numbers from steels, aluminum

Three New Initiatives Move Into the

Winner’s Circle at Ames Laboratory

by Steve Karsjen

(left to right) Gary Osweiler explains the ISU Veterinary

Diagnostic Laboratory’s new quick-response bioterrorism

database to U.S. Rep. Tom Latham and ISU President Gregory

Geoffroy. Congressman Latham had just announced funding

for the MFRC and BRC initiatives.

2002 8 INquiry

A Sure

 Bet
and other metals, and to determine bomb-blast effects upon

metals. “As far as new research efforts, we’d expect to fund

proposals that support ongoing or existing types of analyses,

such as the development of new instrumentation or new

methodologies to support crime labs,” says Baldwin. He’d

also like to see research proposals that support the use of

statistical analysis of classes of evidence. Baldwin says

investigators can already determine the probability that a

human sample matches the DNA of a suspect and the degree

of confidence or the significance of that finding. Now he

says similar statistical methods need to be developed for

analyses to do the same type of matching with bullets, glass

and steel. “This is a hot issue right now because of the way

DNA has revolutionized the way courts use forensic

evidence,” says Baldwin.

Research and development assistance to improve forensic

capabilities is just one part of the MFRC’s four-part mission.

Other focuses include casework assistance for crime labs,

educating the next generation of forensic scientists and

providing forensic training assistance for crime-lab scientists

and law-enforcement professionals. In the area of casework

assistance, the MFRC is building upon the bioterrorism

database idea by developing a database of forensic resources

expertise for criminalists. This expertise, for example,

would allow a criminalist in the Midwest to find and then

consult with technical experts at the Laboratory on a range

of topics, such as materials identification.

In addition to casework, the MFRC’s training program is

also receiving high-level interest. The FBI’s Forensic Science

Training Unit is considering making the MFRC part of its

“virtual” training academy system. In the past, the FBI has

provided training solely at its academy in Quantico, Va., but

the agency has a limited number of trainers and space so it

wants to access the resources of strategic partners nationwide

who are qualified to teach training courses in forensics.

“This approach fits exactly into the type of training we are

equipped to deliver,” says Baldwin, who adds the MFRC is

hoping to use the capabilities of ISU’s Instructional

Technology Center to facilitate its training mission.

Now that the groundwork has been laid, the next several

months will bring a second flurry of activity as efforts are

made to enhance all four of the MFRC’s mission areas.

Those efforts will range from funding more research

proposals to fostering more university/crime lab interactions

to expanding training programs for forensic scientists to

increasing casework assistance. As evidence of this

commitment, the MFRC has already begun offering up to 40

hours of casework assistance for criminologists wanting to

consult with any of Ames Lab’s technical experts. A

confident Baldwin believes he’ll be able to find the support

to help foster all of the MFRC’s goals. “Sometimes you

work on research in a bureaucracy, and everyone is arguing

about what’s important,” Baldwin says. But that’s not the

case with the MFRC, he adds. “Everyone is seeing universal

importance in everything we’re talking about doing.”

Biorenewable Resources Consortium

It’s no secret that the world, and industry in particular,

has a huge appetite for oil and natural gas as energy sources.

It’s also no secret that at the current rate of consumption

these traditional energy supplies will eventually be depleted.

The goal of the Biorenewable Resources Consortium, or

BRC, is to lessen our nation’s dependence on fossil

resources and petrochemicals as energy sources by

developing agricultural alternatives, such as plant matter, or

biomass, to create products and energy. Accomplishing this

goal would help improve U.S. competitiveness

internationally, provide greater crop diversity for farmers,

reduce carbon dioxide emissions from the use of

conventional fossil fuels, help form new industries, and

enhance economic development in rural states like Iowa.

Ames Laboratory is uniquely positioned to play a key role

in the development and use of biorenewable resources as a

sustained supply of energy due to its location in the heart of

the agricultural belt, which provides access to an unlimited

supply of biorenewable resources as well as the ability to

access the world’s most advanced crop research through

ISU. By combining its research strengths with those of its

partners, ISU’s Plant Sciences Initiative and the USDA’s Iowa

Agriculture and Home Economics Experiment Station, the

Lab hopes to take a leadership role in making biorenewable

energy a cost-effective, environmentally safe source for

energy and chemical products.

Congressman Tom Latham announced $2 million in

federal funding for the BRC in January 2002. Since the

announcement, George Kraus, chair of the BRC task force

and an ISU chemistry professor, says the BRC has moved

quickly to issue a request for proposals for research projects

from Ames Laboratory and ISU scientists. Nineteen

proposals have been received. Eleven of those were chosen

to receive on average $80,000 each. “The proposals are

Ames Laboratory’s Todd Zdorkowski (left) and David Baldwin

confer with Jane Homeyer, director of the Forensic Science

Training Unit at the FBI Academy, at the 2002 MFRC annual

meeting. Homeyer urged the MFRC to consider becoming one

of the FBI’s training partners.

2002 9 INquiry
broad-based, ranging from research on issues of fermentation

to composites to catalytic reactions,” says Kraus. “We

believe that a lot of interesting science will emerge.”

A key requirement of the BRC research proposals is that

they are collaborative in nature, meaning they include

interactions between scientists from various disciplines.

The goal of this cross-boundary interaction is to develop

what Kraus calls “interfacial science.”

“We want to bring people together who really haven’t

interacted with one another much,” says Kraus. “Whenever

you bring people together from different areas you almost

always get different perspectives and, hence, new ideas and

strategies for solving problems.” Kraus adds the perfect

research scenario might include engineers interacting with

chemists, who are interacting with food scientists, who are

interacting with people from forestry. “There are some

pretty ingenious proposals being funded,” says Kraus. “I

just can’t wait to see how some of them actually pan out

when we try the science.”

Brent Shanks, an ISU associate professor of Chemical

Engineering, is one of the scientists whose research proposal

has received a grant from the BRC. Shanks proposes taking

a biorenewable resource, such as soybean oil, and producing

dibasic acids by cleaving, or splitting, the fatty acids

contained within. These dibasic acids could be used to

replace adipic acid, which is a basic ingredient used in the

production of nylon. Nylon is used extensively in carpeting

and other products. Industry produces over a billion

pounds of adipic acid each year, all of which is produced

from fossil fuels. Shanks wants to determine if the adipic

acid replacement can be produced from biological sources

rather than fossil fuels. “There’s a great opportunity before

us to get rid of this fossil-fuel-derived material in favor of

one that’s soybean-oil-derived,” says Shanks, who adds that

dibasic acids produced from biorenewable materials also

have the potential to be cheaper to manufacture than adipic

acid made from fossil fuels. It potentially could cost on the

order of 40 cents per pound to produce dibasic acids from

soybean oil, whereas adipic acid costs around 60 cents per

pound to manufacture from fossil fuels. “So not only is

there the potential to get rid of a fossil-fuel-derived material,

but also an opportunity to provide better economics for

industry with soybean-oil-derived material,” Shanks says.

An enthusiastic Shanks says he’s anxious to get started on

his research project and readily admits that without the BRC

funding his project might have been a long time in coming.

“This BRC seed money will allow us the chance to actually

validate that we can do this conversion,” says Shanks, who

adds that this is very important in a scientific world where

funding is often based on results rather than promises of

what could occur. At the same time, Shanks is also looking

forward to the interactions he’ll have with scientists

elsewhere at Ames Laboratory and ISU who have

backgrounds dissimilar to his. In his research project,

Shanks will combine his expertise in chemical engineering

with those of scientists whose backgrounds are in catalytic

conversion of biological feedstocks, advanced catalytic

materials, and oxidation chemistry. “The interplay of this

experience will be needed to successfully complete the

proposed work,” says Shanks.

As for the future of the BRC and of biorenewables

research at Ames Lab and ISU, Kraus says it’s all in the

numbers – numbers of scientists that is. There simply needs

to be more researchers working in the biorenewables area,

says Kraus. “I think we’re primed to do great things, but we

don’t have all the researchers we need to cover all our bases

in biorenewables,” he says. “Ames Lab and ISU have a ways

to go to catch up to other universities that have a much

stronger tradition in biorenewables.” But he adds, “We’re

off to a pretty fast start.”

Green Chemistry Catalysis Laboratory

At the same time the MFRC and BRC were receiving

funding so was the initiative to establish the Green

Chemistry Catalysis Laboratory, or GCCL, at Ames

Laboratory and the Center for Catalysis at ISU. Senator

Tom Harkin announced $500,000 in funding for catalysis

research at ISU.

In order to understand the significance of catalysis

research to Iowa, one must first understand catalysis itself

and its connection to “green” chemistry. Webster’s New

World College Dictionary defines catalysis as “the speeding

up or, sometimes, slowing down of the rate of a chemical

reaction caused by the addition of some substance that does

not undergo a permanent chemical change.” This

phenomenon is used widely in the pharmaceutical, chemical

and energy industries to manufacture all sorts of products,

from pharmaceuticals to cosmetics to cleaner fuels.

Brent Shanks draws a sample of the conversion product from

a batch reactor. This sample will be analyzed for yield of the

desired dibasic acid product.

2002 10 INquiry
Unfortunately, many of the catalytic reactions used in

industry to create these products generate large volumes of

hazardous pollutants, which is where green chemistry

comes into play. Green chemistry refers to chemical

processes that do not harm the environment. These

processes often occur at room temperatures and ordinary

pressures, and use water, preferably, as a solvent. They

require the expenditure of less energy, occur much more

rapidly and produce significantly fewer unwanted

byproducts than competing industrial processes.

According to Kraus, who also directs the GCCL for Ames

Lab, Iowa is in a strong position to capitalize on the growing

relationship between environmentally friendly catalysts and

biorenewable resources. For example, Kraus says there has

been a lot of talk about taking ordinary field crops, such as

corn and soybeans, and converting them into value-added

products. At almost every step of this process, Kraus explains,

a catalytic conversion would be required.

A goal of the catalysis laboratory would be to discover new

catalysts and chemical reactions that operate in an

environmentally friendly manner, which would help the

nation replace fossil-fuel-based feedstocks with those based

on renewable resources, thus ensuring an adequate energy

supply for generations to come. One example of this

relationship would be the creation of new environmentally

friendly catalysts to convert soybean oil into biodiesel fuel.

Another would be biocatalysts to synthesize fine chemicals

for pharmaceuticals. Still another would be new catalysts for

compounds used in flavorings and fragrances. “We hope

some of the catalysts developed in our green chemistry lab

and catalysis center will accelerate the process of developing

these bio-efforts across Iowa,” says Kraus. “Our ultimate goal

is to unearth some new science and develop some catalysts

that could help create new markets for Iowa products,

thereby enhancing Iowa’s rural development,” he adds.

“Our work could potentially lead to the creation of new

industry in Iowa,” says Andreja Bakac, Ames Laboratory

senior chemist, whose project has received funding through

the GCCL. Bakac will use the $50,000 grant to further her

work to develop a heterogeneous catalytic system for the

oxidation of hydrocarbons. Benzene is an example of a

hydrocarbon that she can currently oxidize in a

homogeneous solution. The reaction uses visible light as an

energy source and oxygen as oxidant, but the homogeneous

setup does not allow for easy removal or regeneration of the

catalyst after the completion of the reaction. Rather, the

catalyst is wasted and must be disposed of, which increases

the cost of the process. This problem will be solved if the

transfer to a heterogeneous system is successful. “If we can

develop this new system and get industry interested in it,

perhaps that industry would locate in Iowa,” says Bakac, who

adds that the timing for the GCCL funding is just perfect.

“Without this funding this project would be sitting on a back

burner waiting for other money to come in, if and when.”

Like the BRC, the GCCL initiative hopes to bring together

“teams” of scientists to work on solving mutual problems.

David Hoffman, division director of Science and Technology

at Ames Laboratory and an ISU professor of chemistry,

believes the potential exists for establishing numerous new

cutting-edge research teams in catalysis at Ames Lab and

ISU. For example, Hoffman envisions research teams

consisting of chemists, biochemists, materials scientists and

engineers as well as mathematicians. He adds that many of

these researchers will have already made individual strides

in catalysis research. Creating, fostering and nurturing a

synergy between these individuals is a new challenge he

expects will quickly take root.

“We have already formed our team and we’re working

together,” says Bakac, whose research project is a perfect

example of the synergy of which Hoffman speaks. Bakac is

combining her expertise with that of three other Ames Lab

and ISU scientists – Marek Pruski, Victor Lin and Brent

Shanks – to complete her research project. “We need each

other to make this work,” says Bakac, who, like Hoffman,

believes the team approach is not only good for the research

but also for the researchers. Hoffman adds, “We’re off to a

very smooth start.” ◆

For more information:

David Baldwin, (515) 294-2069

dbaldwin@ameslab.gov

George Kraus, (515) 294-7794

gakraus@iastate.edu

Brent Shanks, (515) 294-1895

bshanks@iastate.edu

Andreja Bakac, (515) 294-3544

bakac@ameslab.gov

Research funded by:

Department of Justice National Institute of Justice

DOE Office of Energy Efficiency and Renewable Energy

DOE Office of Biological and Environmental Research

Andreja Bakac observes photolysis (chemical decomposition

induced by light) in a reaction solution as part of a catalysis

experiment.

2002 11 INquiry
You might call them “control freaks”

of sorts. Ultimately, they’d like nothing

better than the ability to guide what

happens every step of the way, and

they’re making remarkable progress in

that direction.

Don’t misunderstand – Ames

Laboratory researchers Rohit Trivedi,

Ralph Napolitano and James Morris are

great guys, but relentless in their desire

to better understand how

microstructures develop in materials.

Working toward that objective, they’re

studying certain properties that exist in

metals at the interface between the

liquid and solid phases during

solidification.

“We want to have control of the

microstructure,” says Napolitano,

physical metallurgist and an Iowa State

University assistant professor. To gain

that control, he says, “We need to

understand the fundamental principles

that underlie microstructural evolution,

beyond simply tweaking the process

knobs.” The three scientists are

focusing their basic research efforts on

that goal – one that may some day allow

them and others to tailor microstructural

development, providing the basis for

new and improved materials.

What lies between

The Ames Laboratory team has shown

that there are many subtle variations in

microscopic properties at the liquidsolid interface as the solid is “freezing

out.” The small variations depend upon

which crystal face is in contact with the

liquid. Different faces, or orientations,

give slightly different values for

properties such as free energy, mobility,

and stiffness (surface tension); and

these properties play dramatic roles in

how the microstructure of a metal

evolves during solidification.

“The structure observed at the

interface between a solid and a liquid is

strongly dependent upon the

crystallographic plane with which the

liquid is in contact,” says Napolitano.

“In metals, this dependence is

particularly interesting because the

interface is typically ‘atomistically

rough’ and is continuously fluctuating,

so that the crystallography can only be

represented statistically. The nature of

these variations at the atomistic level

ultimately governs the overall behavior

of the interface,” he explains.

Accordingly, Napolitano notes that a

complementary relationship between his

and Trivedi’s experimental approach

and the theoretical predictions of

Morris, a theoretical physicist, has

developed quite naturally. “At the end

of the day, the fundamental knowledge

we’re gaining about crystallographic

dependence of interfacial properties is

critical to the development of various

theories concerning solidification,

crystal growth, and the natural

evolution of microstructure in

materials,” he says.

Trivedi, physical metallurgist and an

ISU distinguished professor, stresses the

importance of the interfacial properties

he and his co-workers are investigating.

“There are some properties that are

extremely small, but they have a

profound influence on interfacial

behavior,” he says. “For example, the

way a snowflake forms depends on very

small factors. It turns out that some of

these small factors are really the

essential ones in determining shape.

INQUIRIES AT THE INTERFACE

Scientists find small effects play huge role in how materials evolve by Saren Johnston

The two-phase structures that form

within the droplets during rapid

quenching from the liquid state reveal

the overall pre-quench equilibrium

shapes of the droplets. Rohit Trivedi

and Ralph Napolitano use such crosssections to quantify the deviation from

sphericality in the quenched droplets.

The deviation is extremely small, but

enough to effect big changes in

microstructural development.

2002 12 INquiry
The same thing is true not only for

materials, but for humans, animals,

plants – anything that grows.”

A couple of “firsts”

Trivedi, Napolitano and Morris are

paying close attention to the small

factors and their effects on

microstructural evolution. “We’re

investigating some very specific

quantities, such as the variation of

interfacial free energy with

crystallographic orientation,” says

Napolitano. He and Trivedi have

developed innovative experimental

techniques that provide the first reliable

measurements of the minuscule

variations in free energy at the liquidsolid interface in metallic systems.

Morris’ complementary calculations

represent the first (and so far, only)

effort to theoretically predict the

variation in interfacial free energy for

aluminum. The combined efforts of the

three scientists provide both a direct

check between the experiment and the

simulation and the opportunity to put

forth new solidification theories.

Napolitano continues, “By revealing the

essential physical behavior of liquid-solid

interfaces, these critical experiments,

both experimental and theoretical, are

facilitating significant advancement in

the theoretical prediction of

microstructures.”

The metallurgists’ method

In experiments designed to measure

small effects on the property of

interfacial free energy, Trivedi and

Napolitano have devised a method to

selectively melt certain microscopic

regions within an aluminum alloy single

crystal, forming a dispersion of tiny

liquid droplets trapped within the solid.

(A single crystal is one in which the

atoms are arranged according to a single

“plan” or “template.’ The orientation is

uniform throughout the material,

creating a simple, symmetric structure.)

The material is then heated to bring the

droplet structures to equilibrium (the

condition at which no change occurs in

the state of a system unless its

surroundings are altered). After rapid

quenching, the droplet shapes are

measured very carefully, and their

equilibrium shapes are determined,

providing the necessary link to interfacial

properties. “Thermodynamics tells us

how the equilibrium droplet shape is

related to the interfacial free energy,”

says Napolitano. “These measurements

provide a direct means for quantifying

the subtle variation of this property with

respect to crystallographic orientation.

The challenge is to accurately measure

the degree to which the droplet shapes

deviate from being spherical, and they

deviate only by a percent or so.”

Trivedi adds, “When you look at the

droplets with your eyes, they look like

spheres. It’s only when you magnify

and measure them precisely that you

find the spheres are altered in certain

directions, so there’s a different energy

in different directions.”

The physicist’s process

Getting a clearer picture of just how

little the equilibrium droplet shape

deviates from a true sphere is Morris’

job. “You’re looking at this droplet and

saying, ‘Well, this droplet isn’t perfectly

spherical; it has some small asymmetry.’

We want to measure that, and we don’t

want it influenced by dirt in the system

or anything else,” says Morris. “The

deviation is a very small number, but it’s

very important, and that’s where doing

the calculations and modeling the

atomic fluctuations of the liquid-solid

interface have come in.”

In parallel with Trivedi’s and

Napolitano’s experiments, Morris selects

a model for how the atoms interact to

calculate the variations in interfacial

properties. To do so, he uses molecular

dynamics simulations of the liquid-solid

interfaces at equilibrium. His work

shows how the atoms behave at the

interface and allows him to track their

equilibrium fluctuations to calculate

interfacial free energy. “You’re

completely relying on whether the

potentials used can provide accurate

calculations, and in this case there’s been

no previous comparison of an

experimental measurement with a

detailed atomistic calculation,” says

Morris. “This is a first, and the fact that

the comparisons come out nicely suggests

that these potentials are suitable.”

Small but mighty

Trivedi emphasizes again that the

small effects dominate throughout

nature. “It’s very obvious in biology –

think of gene expression in the

development of the human embryo.

Many things can go wrong, but by and

large they don’t,” he says. “The same

thing is true for the development of

microstructures in metals. There are

very fundamental issues that govern

what happens. We would like to know

precisely how they influence

microstructure formation. To do that,

we need to understand the small effects.

We study metals, but the principles we

hope to generate will have much

broader applications.” ◆

James Morris produces molecular

dynamics simulations of coexisting liquid

and solid phases, such as the one shown

here, to see how the atoms behave at the

interface. In this image, the red region in

the center represents the disordered atoms

of the liquid phase. The blue and green

regions on either side represent the

ordered atoms of the solid phase. By

tracking the fluctuating region between

the two phases, Morris can calculate the

interfacial free energy.

For more information:

Ralph Napolitano, (515) 294-9101

ralphn@iastate.edu

Research funded by:

DOE Office of Basic Energy Sciences,

 Materials Science and Engineering Division

DOE Office of Basic Energy Sciences,

 Computational Materials Sciences Network

(left to right) Researchers James

Morris, Rohit Trivedi and Ralph

Napolitano are studying the

fundamental interfacial behavior

between liquid and solid phases during

the solidification of metals, with the

ultimate goal being the ability to control

microstructural development.

2002 13 INquiry
Marathon runners call it “hitting the wall.” It’s that point

where the legs tighten, momentum drops, the pace slows,

and the last ounce of energy has drained away. Without a

boost – an energy bar for the body or a word of

encouragement for the mind – the finish line seems

impossible to reach.

Scientists may not have a term for it, but they too can hit

the wall, reaching an impasse where they need help getting

a research project back on track. That lift may be

collaboration with a colleague, bouncing ideas and theories

off a sympathetic ear, or getting access to material or a

piece of equipment that’s well beyond their institution’s

research budget.

Like a runner’s energy bar, the Ames Laboratory’s Process

Science Initiative provides materials scientists with the

necessary boost to help get them over the hump. Now in

its third year, PSI has provided assistance to more than 25

different research projects. The primary assistance comes

in the form of access to the Lab’s Materials Preparation

Center facilities and its personnel providing the materials

science expertise.

Access to MPC

“The program is designed to help materials scientists who

have reached some type of bottleneck,” says Matt Kramer,

PSI program manager and an Ames Lab scientist. “It’s not a

source of summer funding. We really look at how they can

benefit from what the MPC has to offer,” he adds, noting

that it also helps the MPC better fulfill its role as a

Department of Energy national user facility.

Proposals are subjected to a review process to make sure

they are viable and have a strong materials-processing focus

that either looks to improve fundamental understanding of

existing processing techniques or explores new techniques

for producing novel materials. As part of that review, an

Ames Lab researcher with expertise in that particular area is

assigned to follow up on a proposal that shows promise,

discussing the problems being faced and how PSI may help

provide the answers. Ultimately, that Ames Lab researcher

is likely to be assigned as the coordinating principal

investigator on the project if it is approved.

“That’s one of the unique aspects of this program,”

Kramer says. “We have involvement by our researchers

very early in the process, and they work closely with the

project throughout.”

According to Larry Jones, MPC director, the initiative has

helped increase utilization of the center, but also has allowed

the center to serve as a “front door” to Ames Laboratory by

making researchers and their institutions more aware of the

overall expertise and capabilities at the Lab.

“With our ability to fund research projects through PSI,

we underwrite some of the risk in preparing new alloys or

Ames Laboratory assistant scientist Amy Ross checks the status

of a crystal sample being grown in the High-temperature

Bridgman furnace, one of many specialized pieces of equipment

found in the Materials Preparation Center.

2002 14 INquiry
developing new processes,” Jones says, “and bring that

good, fundamental science into the public domain. That

brings recognition to both the MPC and the Lab. It also

provides challenges for us and pushes us to come up with

solutions and ultimately expand our capabilities and offer

even more to the research community.”

 Though the first crop of proposals in 2000 was small –

four projects from Ames Laboratory and/or Iowa State

University that lasted for four months – the program has

grown in successive years. Ten projects were funded last

year, representing Clemson University, North Carolina State

University, the University of Nebraska-Lincoln, Purdue

University, and Texas A&M University, along with Iowa State

University and the DOE’s Brookhaven National Laboratory.

Researchers sing PSI praises

“Fantastic” is just one adjective Richard Figliola, an

aerodynamicist studying fluid dynamics at Clemson

University, uses to describe the program. Figliola is in the

second year of a study with Ames Laboratory senior

metallurgist Iver Anderson in modeling high-pressure gas

atomizer flows.

Though he has known Anderson and his work with highpressure gas atomization – a process used to produce highpurity powdered metals – for a number of years, PSI has

made it possible for Figliola to work directly with Anderson.

Figliola uses experimental data collected by Anderson to

model what happens as the stream of molten material is

broken into tiny spheres by a high-velocity jet of

compressed gas. And the models Figliola has developed, in

turn, have assisted Anderson in modifying and improving

the atomization equipment. The two hold several patents

on the technology.

“We’ve gone from a very basic approach initially to a

pretty sophisticated level both experimentally and

theoretically,” Figliola explains, adding that the pair has

trained a “slew” of graduate students in the technology

along the way. “It’s been a true partnership. When one of

us comes up with an idea, we’ll have the other one try it out.

The only thing that separates us as a research team is the

800 miles between Clemson and Ames.”

In Figliola’s case, working with Anderson has allowed him

to continue research in an area where he would never be

able to afford the state-of-the-art equipment necessary to

carry out experimental tests based on his models. Another

important aspect of the research is the high-purity of the

materials used in the atomization process. Such materials

are a hallmark of the MPC.

University of Nebraska researcher Jeff Shield calls the

MPC “a one-of-a-kind, world-class facility” that’s allowed

him to investigate creating nanoscale intermetallic magnetic

materials through roll-bonding. The problem with

intermetallics, such as neodymium-iron-boron, is they are

too brittle to be formed into ultrathin films like metals.

“We spread a tens-of-a-micron-scale Nd-Fe-B powder on

copper foil and build up many alternating layers,” Shield

says. “Then we diffusion-bond the material at 500 degrees

Fahrenheit (260 degrees Celsius) to help hold it together,

then run it through a rolling mill. When it gets to a

minimal thickness, we fold it up, diffusion-bond it again,

then repeat the rolling, folding and bonding several times.”

As the material is repeatedly rolled, the intermetallic

particles fracture, but appear to disperse fairly evenly

through the surrounding copper rather than forming in

“clumps.” Initial findings show the particles are nearing 25

nanomicrons in size, and Shield hopes to publish his results

in the future.

“It’s been wonderful to work with Scott Chumbley and

the rest of the magnetics group on this project,” Shield says.

“As a university researcher, you might have access to one or

two of the pieces of equipment but the MPC has it all – the

materials; the bonding, milling and processing equipment;

and characterization facilities. It’s a total package not found

anywhere else.”

Shield has more than a passing knowledge of Ames Lab

and the MPC. He received his Ph.D. from Iowa State and

was a scientist at the Lab during the time he was here. That

connection not withstanding, Shield adds that materials

scientists everywhere take a keen interest in what’s

happening at Ames Laboratory.

“Word of mouth is still one of our biggest assets,” Kramer

says of the PSI program. “As people become aware of the

program, they tell their colleagues, and it continues to grow

and expand.” ◆

For more information:

Matt Kramer, (515) 294-0276

mjkramer@ameslab.gov

Research funded by:

DOE Office of Basic Energy Sciences

Materials Science and Engineering Division

Larry Jones (right) discusses a materials request with MPC

senior research technician John Wheelock. The Process

Science Initiative provides access to the facilities, equipment

and staff expertise at the MPC.

2002 15 INquiry
Ames Laboratory senior metallurgist Karl Gschneidner and

his magnetic refrigeration research took center stage for a

time at the Conference of G-8 Energy Ministers in Detroit,

Michigan, in May 2002. Gschneidner welcomed Secretary

of Energy Spencer Abraham to the magnetic refrigeration

display, which also featured a working prototype of a roomtemperature, permanent-magnet-based magnetic refrigerator

built by scientists at Astronautics Corp. of America.

Magnetic refrigeration is based on the magnetocaloric effect,

or the ability of some materials, such as gadolinium, to heat

up when placed in a magnetic field and then cool down

when removed from the field. Magnetic refrigeration is

more efficient than conventional refrigeration and does not

use harmful gases or hazardous chemicals to operate.

Following introductions, the Lab’s display served as the

backdrop for the ribbon cutting ceremony to open the G-8

Conference. The display was one of eight from DOE

laboratories and programs chosen by the Office of Science to

represent DOE in the exhibit at the conference. Conference

participants included energy ministers from the eight most

powerful countries – the United States, Canada, France,

Germany, Italy, Japan, Russia, the United Kingdom and the

European Nation. They work to promote and implement

policies geared toward meeting the global energy and

environmental challenges of the 21st century.

Command Performance

In a command performance, Ames Laboratory presented its

magnetic refrigeration display at a special ceremony at DOE

Headquarters in Washington, D.C., in May 2002. The

ceremony, sponsored by DOE Secretary Spencer Abraham,

was held to mark the one-year anniversary of President

Bush’s National Energy Policy. Secretary Abraham,

Secretary of the Interior Gale Norton and EPA

Administrator Christine Todd Whitman viewed the

magnetic refrigeration display. ◆

INtouch

Ames Laboratory’s

“Cool Work” Makes

a Splash at the

G-8 Conference

DOE Secretary Abraham (right) and Secretary of

the Interior Gale Norton listen as Steve Karsjen,

Ames Laboratory Public Affairs manager,

explains the Lab’s magnetic refrigeration display.

Karl Gschneidner (left) welcomes Secretary

Abraham to the Ames Laboratory display. The

Secretary was joined by Argonne National

Laboratory Director Hermann Grunder (far

right) who, with the Secretary, cut the red ribbon

to open the DOE exhibit at the G-8 Conference.

2002 16 INquiry
It’s a wonderful, investigative tool,” says

Marek Pruski, talking about solid state

nuclear magnetic resonance

spectroscopy. “There are many

applications of solid state NMR,

especially to the study of catalytic

materials. The problem is that it is

difficult to be really good at this type of

spectroscopy and also be an expert in

catalysis,” adds the Ames Laboratory

physicist and solid state NMR guru.

Because NMR is a technique that is

highly developed and requires fairly

extensive knowledge, it usually comes at

the expense of catalysis or other

applications in chemistry and materials

science. “Few people do both really

well,” says Pruski. “Most of the time,

researchers are heavily on one side or

the other. That’s why it makes perfect

sense that this type of expertise exists

within the Department of Energy’s

national labs, where we work as teams.”

It’s all in the name

Defining NMR, Pruski says, “Nuclear

magnetic resonance – the name actually

explains what it does. You look at the

splitting of the nuclear energy levels in a

magnetic field.” When most atomic

nuclei are put in a magnetic field their

energy levels split, and it is possible to

probe the transition frequency between

those energy levels. (The transition

frequency is the characteristic frequency

of radiation that the atomic nuclei must

absorb or release to undergo transition

from one energy state to another.)

“Those frequencies are very sensitive to

the local molecular environment in

which these nuclei find themselves, and

provide an excellent fingerprint of that

site,” Pruski explains. “Monitoring and

understanding these frequencies, this is

what NMR is all

about.”

Not all nuclei

experience NMR.

Only those that

possess a nonzero

total angular

momentum, called

spin, can produce an

NMR signal, or

spectrum. Highresolution spectra, in

turn, can provide

detailed information

about the physical,

chemical and

biological properties

of matter. Solid state

NMR spectroscopy,

Pruski’s specialty, is

used to determine the

molecular structure

and dynamics of solids

and, so, can be used to study catalytic

materials; glasses; other crystalline and

amorphous inorganic and organic

compounds; and biological samples.

The need for narrow

Securing high-resolution spectra for

solids is challenging because Mother

Nature does not provide them naturally

as she does for liquids. In liquids, the

fast, random motion of molecules

results in creating narrow spectral lines.

But solids are another story. “If you

think about a sample that is powdered –

a crushed crystal, for example – the

spectrum is composed of the

contributions from many crystallites,

which are randomly oriented with

respect to the magnetic field and give

resonances at different frequencies,”

says Pruski. “Furthermore, the

contributions from individual

crystallites may be homogeneously

broadened due to dipolar couplings

between nuclear magnetic moments.

These conditions cause severe

broadening of the spectrum, loss of

resolution, and often yield spectra that

are very difficult to interpret.”

Pruski continues, “In NMR

spectroscopy, ‘narrow is beautiful,’

because we are striving to suppress the

broadening interactions to obtain the

highest possible resolution.”

Accomplishing that task in solids

requires manipulating the internal

interactions in the laboratory space by

mechanically spinning the sample; or in

the spin space by applying radio

frequency, or RF, pulses; or by doing

both simultaneously. “In essence, what

we’re trying to do with these techniques

Atomic

Fingerprints

Atomic

Fingerprints

Nuclear magnetic resonance reveals

atomic structure of solids by Saren Johnston

Marek Pruski adjusts the probe containing the sample

of interest that will be examined using NMR

spectroscopy. The NMR spectrometer uses a magnetic

field of 9.4 tesla – five orders of magnitude beyond that

of the earth’s magnetic field.

2002 17 INquiry
is to do what nature does with liquids so

we can achieve line-narrowing in the

spectrum,” says Pruski. “It is usually

easier to obtain high resolution for spin

1/2 nuclei, such as 13C or 1H, where the

anisotropy of the chemical shift and

dipolar couplings dominate the spectra.

(Nuclear spin is measured in the units of

h/2p , where h is a Planck constant. A

total number of protons and neutrons is

odd for spin 1/2 nuclei.) However,

quadrupolar nuclei, those with spins

greater than 1/2, such as 17O, 27Al and 23Na, present a challenge in that

quadrupolar interaction brings about

broadening of the spectrum. The

majority of NMR active nuclei are

affected by the quadrupolar interaction.

“Of course, how else would it be?”

Pruski asks with a laugh.

The quadrupolar quandary

According to Pruski, the quadrupolar

interaction involves a coupling between

the nonspherical distribution of nuclear

electric charge with the local electric

field produced by the surrounding

atoms. In cases where the quadrupole

effects are sufficiently small, the

quadrupolar nuclei can be observed by

using the same techniques as those used

for their spin 1/2 counterparts. More

common, however, are the circumstances

when these techniques fail. Pruski says

this is due to the presence of the socalled second-order effects, which are

negligible in cases of chemical shift or

dipolar interactions. “As a result, you

can’t just rotate the sample around a

single axis and perform some of the RF

tricks you do with first-order effects, and

obtain high resolution,” he says. “It just

won’t work. The crystallites in your

powder would still have different

frequencies of resonance, even though

you’d applied those methods. This has

been known for quite some time, but

people didn’t think it was practically

possible to provide a sufficiently

complex motion to the sample, or do

some sort of spin gymnastics that would

remove the line-broadening.”

However, Pruski notes that two

techniques to do just that were

developed at A. Pines’ lab at the

University of California, Berkeley, in

1988, which used mechanically complex

devices to achieve the effect of motional

narrowing. “One of these methods,

called double-rotation NMR, required

spinning the sample around two

different axes simultaneously at spinning

rates on the order of 105 – 106 rpms ” he

says. “You can only imagine the

sophistication of a probe needed for

those experiments.”

In 1995, a mechanically simpler solidstate NMR technique called multiplequantum magic-angle spinning, or

MQMAS, was developed by L. Frydman

at the University of Illinois, Chicago.

MQMAS only requires spinning the

sample around one axis and uses

multiple quantum transitions to

manipulate the spins and achieve highresolution spectra.

“This is not a very easy experiment to

explain,” admits Pruski, “but once you

get used to thinking about NMR in

terms of coherence pathways and

coherence transfers, the idea becomes

simple. You basically use a coherence

level as another experimental variable

that you can control.” He explains that

two different variables are needed to

achieve line-narrowing effect in the

quadrupolar case. Rather than using

two different axes of rotation to give

motion to the sample, as in the earlier

methods, MQMAS relies upon using two

different coherence states of the spins

and changing those states during the

experiment by means of appropriate RF

irradiation. (Coherence in NMR is a

property of the spin density matrix that

describes the extent to which

interference between the eigenstates of

the isolated spin subsystems persist in

the entire statistical ensemble.) This

provides a two-dimensional correlation

spectrum that contains the highresolution, isotropic information.

Pruski notes that the ideas about

manipulating coherences were known

earlier from liquid state and solid state

NMR spectroscopy of spin 1/2 nuclei.

“As it turns out,” he adds, “the use of

multiple-quantum spectroscopy has also

been an incredibly good idea for the

quadrupolar nuclei in solid state NMR.”

Making the most of MQMAS

Pruski’s interests involve the

development of new NMR techniques

that combine the resolving power of

MQMAS with other solid state NMR

methods to obtain information about

connectivities and distances between

atoms in solids. This effort includes the

use of double-and triple-resonance

experiments in which the correlations

between various nuclear spins are

investigated using through-space

(dipolar coupling) or through-bond

(J-coupling) interactions. Several such

techniques were developed in his group,

including cross-polarization MQMAS;

MQMAS with rotational echo double

resonance, or MQ-REDOR; and twodimensional heteronuclear correlation,

or 2D MQMAS-HETCOR, NMR. “With

proper decoupling schemes, these

techniques can provide the information

about atomic geometries, including

distances, with exceptional resolution,”

says Pruski.

He and his research associate, Jerzy

Wiench, apply their solid state NMR

expertise primarily to the field of

catalysis. “We are interested in

measuring correlations between spins

under the high resolution provided by

multiple quantum spectroscopy,” says

Marek Pruski displays one of the probes

used with the NMR equipment in his

laboratory. The turbine in the probe

spins the sample at almost two million

rpms to overcome the broadening of

spectral lines.

2002 18 INquiry
Pruski. “Currently, we are able to

measure distances between spins in

multispin systems with precision that

approaches that of the diffraction

methods. We don’t need material in a

crystalline form to perform such studies,

although we do require a large number

of spins to generate spectra.” He offers

an example of how such measurements

might be applied in a catalytic system.

“For instance, if there is a molecule

adsorbed in a zeolite interacting with

some catalytically active sites, we can try

to measure the distance between certain

atoms in that molecule and the active

site. This would give us the position of

the molecule within the catalyst and a

better understanding of the activity of

that particular site.”

Pruski and Wiench use their solid

state NMR capabilities in various

collaborative efforts. Among the

collaborations in catalysis are ones with

Glenn Schrader, an Ames Lab associate

and an Iowa State University professor of

chemical engineering, and Robert

Angelici, an Ames Lab senior chemist

and an ISU distinguished professor of

chemistry. Projects in these

collaborations are funded through Ames

Laboratory’s Chemical and Biological

Sciences Program. The most recent ISU

collaborators include Victor Lin, an

assistant professor of chemistry, and

Brent Shanks, an associate professor of

chemical engineering. They have relied

on Pruski’s and Wiench’s expertise in

solid state NMR spectroscopy to provide

data critical to their work on catalytic

systems for nanoscience efforts.

In a Work for Others project, Pruski

and graduate assistant Krishnan

Damodaran are interacting with a

Brazilian company, Petrobras Brasiliero,

using solid state NMR spectroscopy to

characterize aluminum in zeolites and

industrial catalysts.

Pruski emphasizes that his most

important external collaborators include

professors J.-P. Amoureux and C.

Fernandez, from

the French

universities of Lille

and Caen,

respectively, with

whom he has

developed some of

the new solid state

NMR techniques.

Although Pruski

and Wiench

remain focused on

catalysis, they also

seek interactions

with others whose

research might

benefit from the

contributions solid

state NMR can

provide. A current and greatly successful

collaboration with Ames Laboratory senior

scientist Vitalij Pecharsky and associate

scientist Viktor Balema has drawn Pruski

and solid state NMR spectroscopy into the

world of mechanochemistry. His

contributions to their new solvent-free

process of creating organic compounds in

solid state (see “Shaken, Not Stirred,” page

4) has provided the means of verifying

Pecharsky’s and Balema’s experimental

results. “It turned out that solid state

NMR has been a very efficient tool to

analyze not only the products of their

mechanochemical transformations, but

also to monitor the progress of these

reactions,” says Pruski. “You can’t do that

with X-rays. NMR seems to be working

very well, and the collaboration has been

very interesting and fruitful.”

Pecharsky says, “Marek’s expertise and

willingness to collaborate are first-class.

His solid state NMR data were key

components in our research on the

solvent-free mechanochemical synthesis of

molecular compounds because for the first

time we were able to obtain decisive proof

that certain types of reactions between

organic molecules proceed in solid state.

This discovery opens up new opportunities

and presents new challenges for materials

science, synthetic organic chemistry and

solid state NMR spectroscopy. We

continue to work together to gain better

understanding of the mechanisms of these

unconventional processes.”

Pruski and Wiench will continue to

participate in collaborations where their

skill in solid state NMR spectroscopy is

likely to provide the “atomic fingerprints”

needed to resolve questions associated

with the structure of solid materials. “We

enjoy the collaborations a great deal,” says

Pruski, “but we are also very interested in

improving the efficiency and sensitivity of

our experiments and in studying how best

to manipulate the spins. The common

thread in our basic research has always

been the development of NMR techniques

– that is a constant that remains.” ◆

For more information:

Marek Pruski, (515) 294-2017

marek@ameslab.gov

Research funded by:

Doe Office of Basic Energy Sciences,

 Chemical Sciences Division

Petrobras Brasiliero

Jerzy Wiench

inserts a 5-

millimeter rotor

containing the

sample of

interest into the

magic-angle

spinner in one of

the NMR probes.

2002 19 INquiry
Edward S. Yeung, director of Ames Laboratory’s Chemical and

Biological Sciences Program and an ISU Distinguished

Professor, has received the prestigious American Chemical

Society Award in Chromatography. Yeung was honored during

a special awards ceremony at the 2002 ACS national meeting.

The selection of Yeung to receive the ACS Award in

Chromatography speaks to the enormous and impressive

volume of research he has produced in the area of chemical

separations. To be nominated for this award, the individual

must have made an outstanding contribution to the field of

chromatography, with particular consideration given to

development of new methods.

“It is significant to note that Dr. Yeung’s work has contributed

to both our fundamental understanding of chromatography and

to the way chromatography is being practiced today,” says

Michael J. Sepaniak, head of the Department of Chemistry at

The University of Tennessee, Knoxville. A former student of

Yeung’s, Sepaniak nominated him for the ACS award.

Among his many research accomplishments leading to the

ACS Award in Chromatography, Yeung pioneered the method

of multiplexed capillary electrophoresis and in 1995

incorporated the technique into a fluorescence-based DNA

sequencer that dramatically reduced the time needed to gather

information on an individual’s genetic makeup.

Yeung recently combined the technique with absorption

detection, creating a new technology that can gather data on a

much wider range of compounds. His revamped technology

relies on the amount of ultraviolet light molecules in a

compound absorb to determine their type and quantity,

eliminating the need to attach optical tags to those compounds

that don’t fluoresce naturally.

In other work, Yeung has developed a method to track the

activity of single molecules in solution, a breakthrough that

ultimately may have great implications within the fields of

medicine, catalysis and biotechnology. With this approach,

Yeung was able to elucidate the fundamental mechanisms of

chromatography with unprecedented detail.

Yeung has received many awards for his research, including

the ACS Fisher Award in Analytical Chemistry in 1994 and the

ACS Division of Analytical Chemistry Award in Chemical

Instrumentation in 1987. In 2001, he received his fourth R&D

100 Award. He is a Fellow of the American Association for the

Advancement of Science.

Chemistry has always interested Yeung, who grew up in Hong

Kong. After graduating from high school, he came to the U.S.,

earning a bachelor’s degree in 1968 from Cornell University.

Four years later, at the age of 24, he earned his Ph.D. in physical

chemistry from the University of California (Berkeley). It was

his interest in laser spectroscopy that brought him to Ames as

an instructor of analytical chemistry at Iowa State University

INtouch and an assistant chemist at Ames Laboratory. He’s been at Iowa

State and the Ames Lab ever since.

“It is easy to do something that is fun,” he says of his

distinguished career in chemistry, “and it’s been something that

comes naturally to me ... most of the time,” adding that it’s a

bonus to enjoy something “that also pays one’s salary.”

In what may have been a sign of things to come, he became

interested in chromatography through a conversation with Ames

Lab researcher Jim Fritz, who won the ACS Chromotography

award in 1976. “I found out there are challenging unresolved

issues with chromatographic mechanisms and chromatographic

instrumentation,” Yeung says.

Finding answers to those unresolved issues has been the

motivating force behind Yeung’s work. As he explains it, the

answers have come by breaking a complex problem into a series

of questions, then trying to take a novel approach in answering

those questions.

“In general, scientific research starts with simple questions on

how or why things work in a certain way,” Yeung says. “Then,

specific studies are designed to answer such questions.

Satisfaction comes when one is proven correct in proposing the

initial approach or hypothesis, i.e., getting the right answer.

“The biggest challenges are trying to go against conventional

theories or standard approaches and trying to develop

something different, be it an idea or an instrument,” he

explains. “Scientists are, in general, conservative, and many of

our projects would probably have gone unfunded if the exact

plans were laid out in front of grant committee referees.”

Not everything comes as easily to Yeung as solutions to

complex chemistry problems. For example, he points to two of

his favorite diversions.

“I play the violin,” he says and adds that he enjoys art rather

than creating it. “These pursuits are far more difficult to me

than chemistry. Perhaps that’s why I immerse myself in them

whenever I can.”

Though natural talent has its place, Yeung appreciates the

value of hard work in overcoming obstacles. His music has

required that kind of dedication and discipline. “In science,

music or art, more advances come from hard work than sheer

talent,” he says.

He also admits that there’s a certain amount of luck involved

in making scientific discoveries.

“Science often is opportunistic and it is hard to say what

will be discovered next,” Yeung says about where his research

may take him. “For now, I will settle for learning to play the

violin better.” ◆

Natural Born Scientist

by Kerry Gibson

2002 20 INquiry

Ed Yeung uses a microscope and a charge-coupled-device

camera for single-molecule detection research.
Klaus Ruedenberg, an Ames Laboratory senior associate and an

Iowa State University distinguished Professor Emeritus, has

received the prestigious American Chemical Society Award in

Theoretical Chemistry for 2002. Nominees for this honor must

have accomplished “innovative research in the field of

theoretical chemistry characterized by depth, originality and

scientific significance.” His award states that he has seminally

advanced many different, important facets of quantum

chemistry, encompassing fundamental theory, formal

mathematical developments, computational methods and

software implementations, as well as conceptual interpretations.

Modest about his accomplishments, Ruedenberg allows that

“what we end up doing is somewhat accidental. We choose

among the professional options available to us, those that fascinate

us and pose problems we feel we will be able to help solve.”

He grew up in Bielefeld, Germany, where his father worked for

a chemical company. Ruedenberg began his studies by earning

an M.S. in chemistry at the University of Fribourg, Switzerland.

Finding mathematics and theory more attractive than

experiments, he switched to theoretical physics at the University

of Zürich where, in 1950, he obtained a Ph.D. in meson field

theory with the renowned Gregor Wentzel, whom he followed to

the University of Chicago.

There he became a postdoctoral fellow with Roberts S.

Mulliken, who two decades later received the Nobel Prize for

work in theoretical chemistry. “This was then one of the very

few places where one could combine chemistry and theoretical

physics,” Ruedenberg comments, noting that “theoretical

chemistry is one of the invasions of physics into chemistry. Still,

the field would not have blossomed,” he continues, “if it hadn’t

been for the subsequent development of electronic computers.

I was lucky.”

The prominent ACS Award in Theoretical Chemistry honors

him as one of the few quantum chemists in the world to be

recognized as a leader in establishing the field of theoretical

chemistry and ensuring its viability during the last 50 years.

Many of the methods and concepts introduced by him have

become widely accepted and used. “Professor Ruedenberg is one

of the most highly respected and accomplished theoretical

chemists in the world,” says Mark Gordon, director of Ames

Laboratory’s Applied Mathematics and Computational Sciences

Program and an ISU Distinguished Professor. Gordon, who

nominated Ruedenberg for the ACS award, continues, “Klaus’

recognition arises not only because of his outstanding research

accomplishments, but also as a result of his many contributions

to the scientific community as an articulate and inspiring leader.”

Among Ruedenberg’s most noteworthy contributions is his

A Giant Among Us

by Saren Johnston

elucidation of the energetic interactions that cause molecule

formation. It has led to profound insights into the basic origin

and the physical nature of the chemical bond.

Closely related are his methods for creating a rigorous

quantum theoretical foundation for the two-hundred-year-old

empirical model of molecules being built from atoms. His

approach elucidates how atoms get modified in a molecular

environment.

Fundamental theoretical aspects regarding the understanding

of chemical reactions have been illuminated by Ruedenberg’s

studies of molecular potential energy surfaces. His discoveries

regarding intersections of energy surfaces are relevant for photochemistry.

In recent work, Ruedenberg has been addressing the problem

of electron correlation, a major bottleneck in the quest for

accurate predictions of the properties, in particular energies of

ground and excited electronic states of large molecules – a

fundamental as well as practical goal of theoretical chemistry.

Ruedenberg is a Fellow of the American Physical Society, the

American Institute of Chemists and the American Association

for the Advancement of Science. His honors include the

Midwest Award of the American Chemical Society, membership

in the International Academy of Quantum Molecular Sciences,

and honorary doctorates from the universities of Basel

(Switzerland), Bielefeld (Germany) and Siegen (Germany).

For many years, he was editor-in-chief of the scientific journal,

Theoretica Chimica Acta.

While being a consummate scientist, Ruedenberg has not put

aside his early classical humanistic upbringing and remains

fascinated by history, literature and, in particular, the human

mind and its fundamental motivations. But he believes that in

our age basic lessons for these dimensions also flow from the

insights of the natural sciences. He observes, for instance, that

every stationary state in nature is a dynamic balance between

many opposing tendencies – from the motions of electrons to

those of the celestial bodies and from the equilibria in chemical

test tubes to those in living organisms. He thinks that to be a

responsible human means to acknowledge the many mutually

opposing forces in oneself and to affirm the internal tensions and

efforts that go with working out a harmonious moral balance.

 How fortunate for Ames Laboratory that in 1955, when only a

very few chemistry departments showed any interest in

theoretical chemistry, the young ISU professors and Ames Lab

researchers Robert Rundle and Robert Hansen had the foresight

to invite Ruedenberg to Ames Laboratory and Iowa State to delve

into the harmonies of molecular electrons. ◆

INtouch

2002 21 INquiry

Klaus Ruedenberg with the display of a localized molecular

orbital depicting the distribution of electrons in carbon dioxide.
Better performance for less hassle –

that’s the advantage of a new messagepassing library developed at Ames

Laboratory. The library, called

MP_Lite, makes it possible to extract

optimum performance from both

workstation and personal computer

clusters, as well as from large

massively parallel computers. It

supports and enhances the basic

capabilities that most software

programs require to communicate

between computers.

Fewer and faster

MP_Lite might be thought of as a

“slimmed-down” version of the

message-passing interface, or MPI,

standard, a widely used model that

standardizes the syntax and

functionality for message-passing

programs, allowing a uniform interface

from the application to the underlying

communication network. The MPI

standard eases the parallel

programming task by providing a

common syntax for communicating

between computers, making codes

portable between widely varying

supercomputers.

 The full MPI standard contains

many options that most people don’t

use very often. MP_Lite offers only

the core functions of MPI, which are

enough for most codes. The emphasis

is put on implementing these

functions in the most efficient manner,

providing all the performance without

all the extra options. “After all, a

Corvette will go fast and look good

even without a CD player and electric

seats,” says Dave Turner, an Ames

Laboratory computational scientist

and the principal investigater for the

MP_Lite project.

Perfecting performance

MP_Lite could be scaled up easily,

but its objective is not to provide all

the capabilities of the full MPI

standard. “Our goal with MP_Lite is

to illustrate how to get better

performance in a portable and userfriendly manner and to understand

exactly where any inefficiencies in the

MPI standard may be coming from,”

says Turner. He explains that the

MP_Lite library is smaller and much

easier to work with than full MPI

libraries. “It’s ideal for performing

message-passing research that may

eventually be used to improve full MPI

implementations and possibly

influence the MPI standard,” he says.

Turner notes that it was “mainly

frustration” that led him to develop

the MP_Lite library. “Most messagepassing packages are large and clunky

to work with, and can be difficult to

install and optimize. If you run into

any errors at all, they give you very

cryptic messages that mean nothing

unless you actually wrote the library,”

he says. “So a lot of the reason I got

into this project was not just to

improve the efficiency, but also to

improve performance – make the

message-passing more user-friendly.”

Offering an example, Turner says, “If

two processors are communicating, and

one waits a minute for a response from

the other one – well, a minute is a very

long time in this context – the library

should put out a warning into a log file.

But that’s something that’s not done.

Most message-passing systems don’t

tell you what’s wrong if a

communication buffer overflows or a

node is waiting for a message that

never gets sent. What if there’s a fiveNew parallel library succeeds by going easy on the extras by Saren Johnston

2002 22 INquiry
minute wait for a message?” he

continues. “Something is probably

frozen up, so at that point the library

should implement an abort and give

the user as much information about the

current state of the system as possible.”

Turner notes that MP_Lite operates

with minimal buffering and warns if

there are any potential problems.

When possible, MP_Lite will dump

warnings to a log file and eventually

time out when a lockup occurs.

“There’s a lot of these user-friendly

aspects that I’d like to see put into

other message-passing systems,” he

says. “That’s one area that doesn’t get

focused on very often.

“Many of the people developing

parallel library codes don’t necessarily

use them, and it’s not in the MPI

standard that you have to make them

user-friendly,” Turner continues.

“They’re getting paid to add

functionality. For them performance

and usability have been almost a second

consideration, which is unfortunate.”

Putting on the “squeeze”

Turner says MP_Lite was “born out

of a need to squeeze every bit of

performance from the interprocessor

communication between nodes in

personal computer or workstation

clusters, where the Fast Ethernet and

even Gigabit Ethernet speeds are

much slower than communication

rates in traditional massively parallel

processing systems.” This is due to

the fact that although massively

parallel systems have processors very

similar to those of PCs or

workstations, they also have more

customized communications systems

that allow faster communication rates.

“In PC and workstation clusters,

we’re catching up to where we’re

getting at least closer to those rates, but

we still need to squeeze everything out

that we can,” says Turner. “So one of

the things that I do is look for where

we can squeeze it out. Is it at the

message-passing level; in the operating

system, itself; or in the driver

implementations – there’s a lot of

evaluation in the whole messagepassing, or communication, hierarchy

that’s involved in the MP_Lite project.”

In addition to enhancing

performance, another goal Turner has

for MP_Lite is to tie it directly to a full

MPI library. To do so, he’s been

working with the Department of

Energy’s Argonne National Laboratory

and running their MPICH library on

top of MP_Lite. “By doing this, we

can pass the good performance of

MP_Lite on to the full MPI

implementation,” he says. “So we

combine the best of both, keeping the

efficiency of my library and the greater

functionality of Argonne’s.”

Turner says he named the library

MP_Lite for several reasons. The small

size of the library’s code makes it easy

to install anywhere – it compiles in

under a minute. There’s much less

code, so it’s more streamlined than

MPI. It can also be easily modified to

include more of the full MPI functions.

And MP_Lite has its own syntax, which

is simpler and can be used in place of

the MPI syntax. Of course, there’s

always the fun of the clever response

Turner is able to make to people who

say to him, “I use this MPI function;

why isn’t it in your library?” He simply

replies, “Well, it’s ‘lite.’ ”

MP_Lite is on the World Wide Web

at http://www.scl.ameslab.gov Projects/

MP_Lite/ and can be downloaded free

of charge. “I tell people straight out

that it’s an experimental product

under development,” says Turner.

“It’s been a good way of finding out

about bugs in the code.”

Turner admits that the work on

MP_Lite suits him well. “I like the

puzzle aspect of it,” he says. “I like

tuning codes and getting them to run

on a scalable computer, and trying to

squeeze more performance out of

what’s there.” ◆

For more information:

David Turner, (515) 294-1307

deturner@iastate.edu

Research funded by:

DOE Office of Advanced Scientific

Computing Research,

Mathematical, Information and

Computational Sciences Division

Dave Turner shows how the MP_Lite

library is organized in this simplified

sketch. Running beneath a full MPI

implementation, such as Argonne’s

MPICH, MP_Lite can pass on its

efficiency and performance to the

larger library.

MPI Applications

restricted to a subset

 of the MPI commands

MP_Lite

VIA

OS-bypass

TCP

workstations

PCs

SMP

shared-memory

segment

SHMEM

one-sided

functions

MPI

to retain portability

for MP_Lite syntax

Mixed system

distributed

SMPs

MP_Lite syntax

Giganet hardware

M-VIA Ethernet

Cray T3E

SGI Origins

2002 23 INquiry

MP_Lite delivers nearly the full range of performance as the underlying

communication layer, and does so in a portable and user-friendly manner. It can be

run on top of transmission control protocol, or TCP, on clusters of workstations; the

high-performance, native SHMEM library on Cray T3E and SGI Origin systems;

and on any system where MPI is installed to retain complete portability.

Performance is achieved by keeping everything simple and clean.
INtouch

A new state-of-the-art lab is giving Ames Laboratory

researchers unprecedented control to create and, perhaps

more importantly, duplicate thin films with specific

compositions and nanostructures. That ability to control a

number of variables allows thin-film “recipes” to be

developed and compared, resulting in a better understanding

of how thin films work.

Funded by a $530,000 grant from the Roy J. Carver

Charitable Trust, via Iowa State University, the centerpiece of

the Magnetoelectronics Laboratory is a new, custom-built Indel

ion-beam deposition system. It allows researchers David Jiles

and John Snyder to easily and quickly create multilayer thin

films. As Snyder explains it, the system works like a wellplaced break shot in a game of pool.

“To lay down a thin layer of a certain material, you place a

piece of it on a target plate,” Snyder says. “Then the ion beam

blasts that target and a thin layer of the material, maybe only a

few atomic layers thick, is deposited on the substrate, usually a

silicon wafer. Based on the placement of the beam, we know

where the atoms of the target material will wind up.”

The material being deposited must be highly pure, and the

process must take place under extreme vacuum (10-7 Torr or

better) and in a dust-free environment, since even microscopic

dust could cause variations or breaks in the atoms-thin film.

Obtaining high-purity materials is the easy part, thanks to

Ames Lab’s Materials Preparation Center. Clean-room air

handlers control the dust. Achieving such high vacuum,

however, is time consuming – it takes several hours, using both

mechanical and cryogenic pumps.

To speed up the process and minimize the possible

introduction of oxygen, dust or other contaminants, the new

system has a turret with six target plates. This allows Snyder

and Jiles to load six different materials in advance without

having to break and reestablish the vacuum within the

deposition chamber. To deposit the different materials, the

researchers simply rotate the desired target plate into position.

The chamber also has a secondary ion-beam gun that allows

etching of the substrate between layers so the researchers can

remove excess material or “clean” the surface before the next

layer is deposited. They also designed the chamber so they can

heat and cool the deposition substrate, subject it to magnetic

fields, and rotate the substrate table.

“By subjecting the substrate to a variety of conditions, we can

change how the thin-film material grows,” Jiles says. “Particles

may orient differently when exposed to a magnetic field or

grow differently when heated or cooled during deposition. The

Thin-film Fabricator

New lab puts researchers on

thin-film’s cutting edge by Kerry Gibson

beauty of this equipment is that everything is computercontrolled so we can easily recreate a particular ‘recipe’ for any

thin-film wafers we create.”

Having that type of control is crucial because minute changes

in layer thickness or particle orientation may change the film’s

properties. For example, magnetic tunnel junctions consist of a

thin insulating film sandwiched between two magnetic films.

The thinner you make the insulating layer, the less electrical

resistance produced. However any gaps in the insulation will

cause the structure to short out, just like an electrical cord with

frayed insulation.

Magnetic tunnel junctions could replace semiconductor

technology now used for a computer’s random access memory.

When you run a software program, RAM keeps the application

accessible and allows users to read data from memory and write

new data into the memory. However, most semiconductorbased RAM is volatile, meaning that it requires constant

electrical power to operate. If power is lost, so is the data being

held in RAM.

“Magnetic tunnel junctions operate magnetically, so they

aren’t affected by power interruptions,” Jiles says. “You

wouldn’t lose data, and the computer would come on instantly

without going through the boot-up process.”

Thin films can also possess giant magnetoresistive, or GMR,

properties that allow them to undergo dramatic changes in

their electrical resistance in response to relatively small changes

in the magnetic field surrounding them. Their high sensitivity

and small size would make such films desirable for use on the

read-heads on next-generation disks, capable of storing 100-

500 gigabits of data per square inch.

“The research conducted for the Department of Energy is

focusing on the mechanisms of clean, multielement film

growth and the structuring of such films at the atomistic to

nanolength scale,” Jiles says. “It opens whole new areas of

research, and we hope to be able to use the facility as a lever

to attract research funding and to build other projects around

this basic work.” ◆

For more information:

David Jiles, (515) 294-9685

gauss@ameslab.gov

John Snyder adjusts the secondary ion-beam gun that is used in

etching the surface of thin films created in the deposition system.

2002 24 INquiry
Most of the students who competed in the Ames

Laboratory/Iowa State University 2002 Science Bowl were

kindergarteners when the popular science competition

began 12 years ago. And, unbelieveably, some of them

were only preschoolers. Fashions and fortunes, music and

markets, ideas and idols – indeed, nearly all things – have

changed in those dozen years. But the desire to compete

and to win never have and, hopefully, never will because

they keep the heart and mind alive. At Ames Laboratory,

we have been happy observers of that simple fact each

January when we host the annual Science Bowl

competition for up to 48 bright and enthusiastic student

teams from high schools throughout Iowa.

The 2002 event was no different. The competition was

fun, fast and furious throughout the day, ending with a

championship match that saw the team from Cedar Falls

High School in Cedar Falls, Iowa, winning the regional

competition. With that victory, they also won the right to

participate in the Department of Energy’s National Science

Bowl in Washington, D.C., in May. ◆

The Competition

Continues

2002 Science Bowl makes it

an even dozen

INtouch

2002 25 INquiry

Students from Cedar Falls High School in Cedar Falls, Iowa,

display the $1,000 check they received for their school’s science

department as a result of finishing in the top 18 out of 64 teams

at the DOE’s National Science Bowl.

It’s a happy moment for Cedar Falls coach Robert Nelson

(right) as Ames Laboratory Director Tom Barton congratulates

him and members of the Cedar Falls student team on winning

the 2002 Ames Lab/ISU Science Bowl

Concentration and collaboration are key ingredients in Science

Bowl competition, as this team from Ames High School in Ames,

Iowa, demonstrates.

Students from Iowa City West High School in Iowa City,

Iowa, say it was “girl power” that led them to a third-place

finish in the Ames Lab/ISU 2002 Science Bowl. They were

on one of the few competing teams made up of more girls

than boys.
Ames Laboratory

111 Technical and Administrative Services Facility

Ames, Iowa 50011-3020

(515) 294-9557

http://www.external.ameslab.gov

A U.S. Department of Energy

laboratory operated by

Iowa State University

INquiry

Ames Laboratory is a U.S.

Department of Energy laboratory

seeking solutions to energyrelated problems through the

exploration of chemical,

engineering, materials and

mathematical sciences, and

physics. Established in the

1940s with the successful

development of the most

efficient process to produce

high-purity uranium metal for

atomic energy, Ames Lab now

pursues much broader priorities

than the materials research that

has given the Lab international

credibility. Responding to issues

of national concern, Lab

scientists are actively involved in

innovative research, science

education programs, the

development of applied

technologies and the quick

transfer of such technologies to

industry. Uniquely integrated

within a university environment,

the Lab stimulates creative

thought and encourages

scientific discovery, providing

solutions to complex problems

and educating tomorrow’s

scientific talent.