Cool cloud studies

Polar bear sightings, 24-hour daylight and knee-deep

puddles of slush ... in the search for answers to questions

on global warming, Jim Liljegren didn’t mind enduring a

few hardships.

3

INtouch

Touch base with some Ames Lab highlights of the past year.

6

13

Three Ames Lab researchers are hoping that magnesium will

rev up a new class of rechargeable batteries that will be

powerful, inexpensive and environmentally safe.

Power to the People Susan Dieterle

On Thin Ice Susan Dieterle

9

Small structures composed of molecules containing a dozen

or fewer interacting magnetic ions are a dream come true for

physicists who are investigating molecular magnetism.

Simple Systems Saren Johnston

Ames Lab researchers are achieving supercomputing power

for far less cost by improving the communication between

personal computers in large PC cluster networks.

A Case for Clusters Saren Johnston

16 Mufit Akinc is on a quest for the Holy Grail of materials

science – a high-temperature material to replace superalloys

in the next generation of automobile and airplane engines.

The Dragonslayers Susan Dieterle

John McClelland and Roger Jones have found a new

application for a tried-and-true technique. Learn how

transient infrared spectrometry is being applied to the paper

industry.

Features

 1998

1

Giving Cancer the One-Two Punch Saren Johnston

Ames Lab’s 1998 R&D 100 award-winning technology unites

two established analytical methods, creating a novel device

that may pack the power to take cancer down for the count.

Features

Powerful powder

Seeing the Forest from the Trees Steve Karsjen

19

22

24
Letter from theDirector

The journey to unravel the secrets of science is a fascinating, yet challenging

quest. And as they have for more than five decades, Ames Laboratory scientists continue to eagerly challenge any and all limitations, finding solutions

where roadblocks existed in the past.

Ames Laboratory conducts its research as one of

the U.S. Department of Energy’s national laboratories. Well equipped to pursue the challenges

that confront our nation and world in energy

research, Lab scientists this year investigated

scientific challenges that were diverse in scope, not

only in terms of area of endeavor but also locale.

Here at home, two of our scientists conducted

research to help advance the understanding of an

individual’s risk of getting cancer from chemical

pollutants. Their important discoveries netted the

two a prestigious R&D 100 Award. Venturing far

away from the familiar setting of Iowa, another of

our scientists boarded an icebreaker in the far

reaches of our planet, the Arctic Ocean, to conduct research that may help unlock the secrets of

how clouds affect our global climate.

These fascinating research efforts are just two of the scientific highlights

included in this issue of Inquiry. I invite you to turn the page and witness the

myriad ways in which our scientists reach beyond traditional boundaries to

produce good science that ultimately may enrich the lives of the American

public.

 1998

2
ONE-TWO PUNCH!

They surround us. There’s

no way we can completely escape

them. But if we can learn more

about the damage they do to our

DNA, we might be able to combat

them.

Cancer-producing pollutants,

such as those found in cigarette

smoke, automobile exhaust fumes

and power plant emissions, invade

our bodies every day. Over time,

the onslaught can create internal

havoc as these carcinogens mix

with our cellular DNA, the macromolecule that carries our genetic

code of life. The chemistry that

takes place causes DNA damage

and produces byproducts known as

DNA adducts, which can lead to

mutations. If scientists can identify these byproducts, they may be

and Gerald Small, senior chemist,

combined two well-established

analytical methods to create an

innovative, on-line technique called

capillary electrophoresis _ fluorescence line-narrowing spectroscopy

(CE-FLNS).

“The marriage of capillary

electrophoresis (CE) and fluorescence line-narrowing spectroscopy

(FLNS) is an exciting addition to

the rapidly evolving field concerned

with selective detection methods

that can provide the information

necessary to distinguish between

structurally similar molecular

compounds,” says Jankowiak.

The power behind the

punch

The novel CE-FLNS combination can provide more detailed

information on complex

biomolecular samples than either

CE or FLNS can do on its own.

CE-FLNS first takes advantage of

the ability of CE to separate minute

amounts of closely related biological analytes, or compounds. The

second half of the technology

combination, FLNS, is a highresolution, fluorescence-based

detection method that was perGIVING

CANCER

THE

able to discover which ones lead to

cancer.

Searching for

needles in haystacks

Looking for specific DNA

adducts may sound like an uncomplicated plan, but if you’re the

person doing the searching, you

know just how frustrating it can be.

Identifying structurally similar

cancer-causing compounds and

closely related DNA adducts can be

a chemical analysis nightmare. A

complex biomolecular mixture, such

as urine, can contain almost a

thousand different compounds.

And it can become extremely

exacting trying to identify the seven

or eight metabolites of interest from

the hundreds of others.

Hoping to ease this predicament, Ryszard Jankowiak, scientist,

 1998

3

PUNCH!

by Saren Johnston

Ryszard Jankowiak (foreground)

 and Gerald Small may have brought us

 one step closer to uncovering cancer’s

path with their high-resolution CE-FLNS

technology.
hand that it has played a vital role

in detecting modified DNA,” he

says. “The new CE-FLNS methodology for on-line structural

characterization should significantly enhance the potential of

high-resolution spectroscopy, which

has already been shown to be the

most powerful method to analyze

DNA adducts derived from polycyclic aromatic hydrocarbons.”

(Polycyclic aromatic hydrocarbons

make up a potent class of chemical

carcinogens.)

Remarkable regulator

Fundamental to the CE-FLNS

technique is Jankowiak’s and

Small’s design of a compact and

reliable capillary cryostat that

regulates and maintains the constant low temperature required for

FLNS characterization. The

uniquely designed cryostat consists

of a double-walled quartz cell that

encloses the capillary (a tube with a

very small diameter) housing the

CE-separated analytes. The capillary cryostat is the critical link that

unites the CE and FLNS techniques. Gases and vapors are

removed from the outer portion of

the cryostat, and inlet and return

lines introduce and circulate

cryogenic liquids, either liquid

nitrogen or liquid helium.

Liquid nitrogen is used to cool

analytes to 77 K (-321 F) when

low-resolution spectroscopy is

sufficient for identification purposes. But when high-resolution

spectroscopy is required, liquid

helium is used to cool the capillary

and CE-separated analytes to 4.2 K

(-452 F) in less than one minute.

The frozen and stationary analytes

can then be sequentially characterized, or “fingerprinted,” by FLNS

as the capillary cryostat with the

enclosed capillary moves automatically along a transmission stage and

passes through the laser-excitation

region.

More to come for the

combo

Although Jankowiak and Small

have used CE-FLNS primarily for

research on DNA damage from

chemical carcinogens, they’ll tell

you there’s definitely more in store

for the unique technology combination. Potential applications

include other areas of biological

research, as well as forensic science.

“Our technology has applicability well beyond just the problem of

cancer,” says Small. “It could be

fected at Ames Lab

for analytical purposes. FLNS makes

its contribution to

resolving the “molecular identity

crisis” by characterizing the CE-separated

molecular samples. The process

differentiates structurally related

analytes by laser exciting them to

fluoresce and emit fluorescence

line-narrowed spectra, which can

be collected and measured.

The power of CE-FLNS was

demonstrated in work with the

Eppley Institute for Research in

Cancer and Allied Diseases at the

University of Nebraska Medical

Center. The research led to the

discovery of a new pathway that

chemical carcinogens take for their

attack on DNA. “But CE-FLNS

makes such research easier and

misidentification of analytes far less

likely,” notes Jankowiak. “Its online capability is especially important when dealing with minute

quantities of biological materials.”

Michael Gross, professor of

chemistry and medicine at Washington University in St. Louis, has

collaborated with Jankowiak and

Small on research to detect and

identify trace amounts of pieces of

DNA that have been modified by

carcinogens. He expresses high

regard for the capabilities of the

CE-FLNS system. “I watched with

interest the design, assembly and

successful testing of the prototype

CE-FLNS system, and I know first-

 1998

4

“It’s on-line 

 with minute 

The success of CE-FLNS is due to

the design of the compact and fastcooling capillary cryostat that

unites two established analytical

techniques, allowing superior

identification and characterization

of structurally similar compounds.
 1998

5

capability is especially important when dealing

quantities of biological materials.”

For more information:

Gerald Small, (515) 294-3859

gsmall@ameslab.gov

Current research

funded by:

DOE Biological & Environmental

Research Office

 Ryszard Jankowiak and

Gerald Small received a 1998

R&D 100 Award for their novel

CE-FLNS technology. Their

award brings to 13 the number

of such prestigious awards

Ames Laboratory has earned

since 1984.

 The R&D 100 Awards Program, now in its 36th year,

honors the top 100 products of

technological significance that

were marketed or licensed

during the previous calendar

year.

Ryszard Jankowiak, (515) 294-4394

jankowiak@ameslab.gov

used for virtually any biological

problem where one has to deal with

and unravel complex biological

mixtures. We haven’t even begun

to explore all of

the pos-sibilities

yet.”

The CEFLNS technology

is already being

investigated by

several companies, and

Jankowiak and

Small hope to

have it licensed

and on the

market in three

years. While all

this activity is

taking place, the

two researchers

are simultaneously looking

at ways to enhance the capabilities of CEFLNS.

“We’d like to do a secondgeneration cryostat and then

improve the collection optics to

give us more sensitivity,” says

Small. “At the present time, the

capillary cryostat moves only in the

direction of its axis. We’d like to

put a three-dimensional, or x-y-z,

transmission mode in there, too, so

it makes it very easy to align the

capillary.”

But perhaps it is Jankowiak’s

and Small’s fundamental idea and

method of pairing two exceptional

This is a calculated structure of a DNA adduct that the CEFLNS instrumentation was able to identify in the urine of

a test group of smokers. The study was done in collaboration with Dr. George Casale of the Eppley Institute for

Research in Cancer in Omaha, NE.

analytical techniques that will

allow them to best improve upon

and expand their efforts in on-line

characterization of structurally

similar compounds. “The versatility of our basic concept can be

increased by coupling FLNS with

as many different separation

techniques as possible,” says

Jankowiak.◆
 electric car whirs along

 the street as the driver

heads home from work. Instead of the

noxious fumes emitted by gasolinepowered cars, this vehicle’s exhaust

consists of little more than water.

As the power gets low, the driver pulls

into a station where a technician

removes the spent fuel container and

replaces it with a fresh one.

The driver grabs her cellular phone

to let her family know she’s on her way.

This phone battery lasts longer than

the older style and doesn’t contain

the toxic elements used in

earlier batteries. The same is

true of the rechargeable

batteries in the power tools

and electronics at her home.

If you think a scenario such as this

won’t unfold during your lifetime,

think again. Scientists and manufacturers throughout the world are

elbows-deep in efforts to develop new

types of rechargeable batteries and fuel

cells that are powerful, inexpensive and

environmentally safe.

Part of this effort involves researchers at Ames Laboratory: Vitalij

Pecharsky, scientist; Iver Anderson,

director of the Metallurgy and Ceramics Program; and Jim Foley,

associate metallurgist. Along with

colleagues at four other institutions,

they are developing a new class of

hydrogen-storage materials for rechargeable batteries and fuel cells.

They hope their work will help

make cleaner, safer battery power

possible – soon.

“Successful completion of our

project can really affect the everyday

lives of our children and future generations who will place ever-increasing

reliance on electrically powered

appliances, electronic devices and even

electric cars that use the clean, quiet,

portable power from batteries or fuel

An

heavy, bulky

storage tanks. The most attractive and

safest option involves using certain

types of metals and alloys that form

unstable hydrides that are capable of

absorbing hydrogen in a solid crystalline form and then releasing it when

heated.

“By using the metal hydrides, you

are not stuck with cryogenic equipment, you are not stuck with high

pressure,” Pecharsky says. “Instead,

you have hydrogen trapped inside the

metal matrix, which is very safe.”

Foley is among those who believe

that metal-hydride batteries will be the

batteries of choice in the future.

“Current and future metal-hydride

batteries are considered ‘green,’ or

environmentally friendly, because they

don’t contain any heavy metals, such as

lead or cadmium, that can pollute

groundwater,” he says.

Some products, such as cellular

phones and power tools, already use

metal-hydride batteries. Nickel is a

basic component in most of the

current hydrogen-storage materials.

Other common alloy components are

rare earths, zirconium and titanium.

When a rechargeable nickel metalhydride battery goes through the

charging process, hydrogen ions from

 1998

6

by

Susan

Dieterle

cells,” says Anderson, who

is also an adjunct professor of

materials science and engineering

at Iowa State University (ISU).

Hydrogen’s appeal

The goal of the $8.2-million,

three-year project is to develop a new

class of magnesium-based alloys that

can reversibly store and release hydrogen. In addition to Ames Laboratory,

the other participants are Ovonic

Battery Co., Crucible Research, Oak

Ridge National Laboratory and the

Colorado School of Mines.

Hydrogen is an appealing fuel

choice because it is a clean, abundant,

endless source of energy. When it

burns in Earth’s oxygen atmosphere, it

produces water, which can then be

broken back down into hydrogen and

oxygen.

“Hydrogen is an almost ideal

fuel,” says Pecharsky, who is also an

associate professor of materials science

and engineering at ISU.

But using it presents a few

difficulties. To be used as a liquid,

hydrogen would have to be maintained at 20 degrees above absolute

zero, requiring costly cryogenic

equipment. It also can be stored as a

compressed gas, but this creates an

explosive hazard and would involve

PowertothePeople
The HPGA nozzle developed by Iver Anderson helps produce ultrafine metalpowder particles with uniform, spherical shapes.

the electrolyzed water present in

the battery are reduced and

turned into hydrogen gas, which

is absorbed by a cathode made of

the metal-hydride material.

When the process is reversed, the

hydrogen oxidizes and reunites

with the oxygen, forming water

and producing an electrical

current in the battery.

In a fuel cell for an electric

car, hydrogen is drawn from the

metal-hydride material and then

chemically combined with

oxygen from the air. This

reaction takes place within the

fuel cell and generates electricity

to power the car.

Hopes for magnesium

So, with all of the advantages

offered by metal-hydride batteries,

why is it difficult to find them on the

market right now? Mostly because

they are too heavy and too expensive.

Current metal-hydride alloys absorb

only about 1 to 1.5 percent hydrogen

by weight, meaning that storing 1

kilogram of hydrogen requires 99

kilograms of metal-hydride material.

They also contain costly elements,

such as zirconium, which are sometimes in short supply.

In the search for an abundant raw

material that is lightweight, inexpensive and stores more hydrogen, project

participants have turned to magnesium. Pure magnesium meets all of

the criteria and stores about 6.5

percent hydrogen by weight. “If you

think about the commercial applications of magnesium-based alloys, the

potential is almost limitless – it’s

huge,” Pecharsky says.

Magnesium has one drawback. It

must be heated to 500-600 C (about

1000 F) before it will release the

stored hydrogen. But project participants believe they can solve that

problem by modifying the magnesium

with other elements.

Developing the new magnesium

alloys will be the responsibility of

Ovonic Battery, a world leader in

metal-hydride batteries, with metallurgical assistance from Ames Lab. “The

Ames Laboratory is the leading

laboratory in the metallurgy field,”

says Rosa Chiang Young, vice president of advanced materials development for Ovonic Battery. “We need

the expertise and all of the experience

from Ames Lab to help design this

material and really make the program

move forward.”

Oak Ridge National Laboratory

will research different forms in which

the alloy can be used. Crucible

Research, a company with expertise in

powder metallurgy, will concentrate

on large-scale, commercial production

of the powdered form of the alloys.

The Colorado School of Mines will

research ways to minimize the effect of

corrosion on battery performance.

1998

7

Turning

metal into

powder

 In addition to

assisting Ovonic

Battery with the

development of the

alloy, Ames Lab has

another crucial task.

During the next two

years, Pecharsky,

Anderson and Foley

will research the most

efficient, cost-effective

way of turning the

alloys into versatile

metal powder.

 “There’s no easy

way to manufacture sheets or wires or

screens out of these types of materials

because the alloys are intermetallic

compounds, and they are brittle,”

Pecharsky says. “The basic way

hydrogen-storage alloys are used in

batteries is in the form of powders.

Jim Foley (left) and Vitalij Pecharsky have high hopes

that the HPGA process will produce high-quality, longlasting alloy powders for rechargeable batteries.
A powder is much more flexible.”

Turning the alloys into finegrained metal powders is no easy task,

though. Most commercial powder

producers cast the molten alloy into

ingots weighing several hundred

pounds, let them solidify and then

grind them into powder. But this

process can take days, and because the

metals within the ingot segregate

during the solidification process, the

resulting powder particles do not all

have the same chemical composition.

“It gives you inconsistent quality,”

Pecharsky says.

The Ames Lab team believes the

best way to process the magnesium

alloys will be through a technique

known as high-pressure gas atomization (HPGA), which excels in producing ultrafine powder particles.

In HPGA, a stream of molten

material is blasted with extremely cold

argon or helium gas at up to three

times the speed of sound. This

converts the material into fine liquid

particles that solidify quickly and are

nearly spherical in shape. Because of

the rapid solidification, the particles

have virtually identical chemical

compositions. Pecharsky says the

homogeneity of the HPGA powder is

a big advantage over the powder made

from crushed ingots.

“With HPGA, essentially 100

percent of the yield is the target

alloy,” he says, noting that the resulting powder is also cleaner because it

doesn’t require any additional

grinding.

Anderson says the HPGA –

produced powders will also be more

powerful and will enable the metalhydride batteries to last longer. “A

clear performance advantage we expect

for the spherical atomized powder is a

much longer cycle life in rechargeable

batteries,” he adds.

 1998

8

The new generation of rechargeable batteries won’t contain lead and cadmium, which are environmentally

harmful materials.

hurdles to getting metal-hydride

batteries into the mainstream are cost,

weight and performance. We think

that our knowledge of materials and

processing can overcome most, if not

all, of those hurdles.”◆

For more information:

Vitalij Pecharsky, (515) 294-8220

vitkp@ameslab.gov

Iver Anderson, (515) 294-4446

andersoni@ameslab.gov

Jim Foley, (515) 294-8252

foley@ameslab.gov

Current research

funded by:

Department of Commerce, National

Institute of Standard’s Advanced

Technology Program

DOE Basic Energy Sciences Office

In fact, the metal-hydride batteries may well outlast the products they

power. “When electric cars become

more of the norm, the body of the car

will need to be replaced before the

batteries have reached their useful

lifetime,” Foley says.

Cutting costs

Using HPGA would make the

processing simpler, faster and less

expensive than current methods – a

crucial step in lowering the overall

price of metal-hydride batteries and

fuel cells.

“Right now, a lead-acid car

battery costs $40 to $50. If you

wanted to replace it with a nickel

metal-hydride battery, you would be

looking at $300 to $400, and that

would be a tough sell,” Pecharsky says.

“But if the cost of the battery could be

reduced to around $100 per battery

and it was smaller, much lighter,

much safer and stored much more

energy, people would start buying

those batteries.”

Foley adds, “The three main

“The Ames Laboratory is the leading

laboratory in the metallurgy field.”
On ThinIce On

The Canadian Coast Guard’s Des

Groseilliers sits in the heart of the

drifting arctic ice pack.

“It was hard not knowing when

we would be able to leave,” he says.

“But it was wonderful to see all of

the things you’d read about or

modeled actually occurring. It was

fantastic.”

Liljegren, an atmospheric

researcher at Ames Laboratory, was

one of several scientists from

throughout the world who volunhad warily watched for polar bears

prowling the ice in search of seals –

or anything else – to feed on.

Those two months had given

him a firsthand view of both the

harshness and the wonder of nature.

As the Polar Sea bucked through the

expansive ice pack, propelling itself

on top of the ice until the sheer

weight of the ship crushed through

the 12- to 16-foot-thick floe,

Liljegren thought about the ups and

downs of his experience.

 1998

The popping and exploding Jim

Liljegren heard on July 4, 1998,

didn’t come from fireworks.

It came from arctic ice being

crushed beneath the hull of an

icebreaker that was carrying Liljegren

toward the solid footing of the North

American mainland for the first time

in eight weeks – two weeks past his

scheduled June 23 departure date.

The ice pack surrounding the

ship where he had been stationed was

cracking and melting, making it

impossible for the scheduled plane to land safely.

He was forced to wait

until a second icebreaker, the Polar Sea,

could pick him up

along with the 13

scientists and 18

crewmen due to leave

with him.

Extreme vigilance

had been a necessary

part of his life for the

past two months.

Before taking each

step, he had carefully

probed the ice in

front of him to make

sure he didn’t sink

into a slushy hole

where the underlying

ice was only a few

inches thick. And he

9

by Susan Dieterle

Jim Liljegren believes data from the microwave

radiometer will provide a better picture of the relationship between polar clouds and global warming.
with water, this warming

will cause more water to

evaporate into the air,” he

says. “Water vapor blocks

heat from escaping to

space, so this causes

additional warming,

which causes additional

evaporation, and so on.

“But sooner or later,

water vapor condenses

into clouds, which are

made of liquid-water

droplets or ice crystals or

both. Liquid-water

clouds are very effective

at keeping heat from

escaping Earth’s surface,

but they also tend to cool

the planet.”

For now, scientists don’t know

whether an increased cloud cover

would enable Earth’s climate to

balance itself or cause atmospheric

temperatures to escalate. To gather

the needed cloud data from a variety

of longitudes, ARM has radiometers

at three strategic sites: the Great

Plains in Kansas and Oklahoma; in

the equatorial region near New

Guinea; and at Barrow, Alaska.

When the National Science

Foundation began planning an indepth study of the arctic climate,

they wanted ARM to participate.

The study is known as the Surface

Heat Budget of the Arctic Ocean, or

SHEBA. As part of the overall fiveyear SHEBA project, one year would

be spent on the ice pack gathering

polar climate data, and the next four

years would be spent analyzing the

data and applying the findings to

climate models.

 Among the instruments ARM

 1998

10

teered for a six-week shift aboard the

Des Groseilliers, a Canadian icebreaker intentionally frozen into the

arctic ice pack for 13 months to

study polar climate conditions. The

Des Groseilliers mission is at the heart

of a five-year climate study funded

by the National Science Foundation

and the Office of Naval Research.

Data collected during the mission

will be used to improve the accuracy

of climate models in order to make

better predictions of how global

warming might affect Earth’s climate.

Polar data is crucial; most of the

sun’s heat strikes Earth at the equator

and is then carried toward the poles

where it dissipates back into space.

Unless the models contain accurate

information on

the interactions

of water, air and

ice at the poles, their predictions will

be faulty. Prior to the Des Groseilliers

mission, it had been more than 100

years since the last long-term study

of the arctic climate.

Liljegren’s involvement with

climate research began seven years

ago when DOE was looking for

volunteers for its Atmospheric

Radiation Measurement (ARM)

program, which studies the role

played by clouds in maintaining a

balance between incoming heat from

the sun and outgoing heat radiating

from Earth. Liljegren, then a mechanical engineer at Pacific Northwest National Laboratory in eastern

Washington, was intrigued.

He began working with ARM’s

microwave radiometers, sensitive

radio receivers tuned to the frequencies at which water vapor and

liquid water emit tiny amounts of

energy. The strength of the signals

indicates the amount of water vapor

in the atmosphere and liquid water

in clouds. Clouds play a critical role

in climate models and in the ongoing

debate over global warming.

Liljegren notes that although carbon

dioxide is the trigger for the so-called

“greenhouse effect,” water vapor is

the controlling factor in the phenomenon.

“Doubling the carbon dioxide

concentrations produces only a slight

warming in Earth’s atmosphere, but

because most of Earth is covered

 “You get this sense of smallness because the ice seems to go on forever.” “You get this sense of smallness because the ice seems to go on forever.”

Throughout his two-month stay, Liljegren and other

scientists checked instruments in the outlying ice camps

(pictured left) and kept an eye on data transmissions

aboard the ship.
75° N

70° N

Barrow

Prudhoe Bay

SHEBA Ice Station

October 2, 1997

August 31, 1998

Liljegren’s time

aboard the ship

sent to the SHEBA site was a

microwave radiometer, which

made Liljegren eligible for a six-week

shift. Even though cold temperatures aren’t his favorite (“I put on a

sweater when the air conditioner is

on,” he says with a laugh), he eagerly

signed on.

He wanted a shift in the early

summer when the sun is up continuously so he could see the clouds the

radiometer was measuring. Fortunately for him, that also meant

relatively warmer temperatures and a

better chance of spotting polar bears

that might be lurking near the ship.

He and the other scientists received

gun-safety training in case of a polar

bear attack.

On May 11, he traveled to

Barrow, located on the northernmost

tip of Alaska. From there, he

boarded a Twin Otter plane along

with a fresh rotation of scientists and

crewmen and a load of supplies. The

plane flew to the SHEBA site every

three weeks for personnel exchanges

and supply drops and was the sole

source of transportation between the

ice camp and the mainland.

During the two-hour plane

flight, Liljegren was struck by the

vastness of the ice pack. “You get

this sense of smallness because the ice

seems to go on forever,” he says.

“You realize how very hostile the

environment is.”

you were going and stay in contact

with them. At first it seemed a little

burdensome, but you had to take

reasonable precautions to be safe.”

Fog and snow frequently

shrouded the ice pack, making it

difficult for scientists to see the ship

from the instrument sites – and

making it difficult to spot an approaching polar bear. There were no

In addition to the microwave radiometer, Liljegren

was responsible for checking other ARM solar and

infrared radiometers.

 1998

11

Life in the Arctic took

some getting used to.

Because the sun never set

and because there was so

much to learn at first,

Liljegren sometimes found

himself staying up for 20-

22 hours straight. He

gradually developed a

routine so that he’d know

when to sleep. Each day, he

would check the data

recorded during the night

by the various ARM instruments, and then physically

inspect each instrument to

clear moisture from the

lenses, re-level the stands

that shifted in the melting

ice and make sure they were

positioned properly to track

the sun. He also helped

other SHEBA scientists,

sometimes standing guard

for polar bears while the

researchers checked their

instruments on the ice.

Venturing onto the ice was never

an easy task. Though temperatures

seldom rose above freezing, the wind

chill made it as cold as 40 degrees

below zero. “You couldn’t just take a

little walk around the ship,”

Liljegren recalls. “First, you had to

dress appropriately, then you had to

check out a radio and a gun and you

had to let the bridge know where
Fog and snow frequently shrouded the

 ice pack, making it difficult for scien-

 tists to see the ship from the instrument

 sites – and making it difficult to

spot an approaching polar bear.

polar bear attacks, although seven

bears were sighted during a two-week

period beginning in late May.

Anytime a bear got within 1,000

meters of the ship, crewmen set out

on either snowmobiles or the helicopter to chase it away. With the

scientific staff spending several hours

each day out on the ice, a hungry

bear would have posed a real threat.

By keeping the bears clear of the

SHEBA site, neither the bears nor

the group members were harmed.

A different kind of danger

gurgled beneath their feet. The ice

pack melted more rapidly than

expected. Large cracks, known as

leads, fractured the ice floe. Near the

end of May, the crew tied the ship to

large mooring posts that had been

driven into the outlying ice, a

precaution designed to secure the

ship and keep the ice from shifting as

it started to break up. By mid-June,

the ice immediately around the Des

Groseilliers’ hull had melted, allowing

the ship to float within the ice pack.

Melt ponds now covered the ice.

Ponds with white bottoms indicated

that somewhere below the slush was

“multi-year ice” that would never

completely melt and would support

Liljegren’s weight as he stepped on it.

Darkened melt ponds, however,

indicated that the ice was only a few

inches thick.

Life inside the ship was less

forbidding. His 8’ x 12’ cabin was

comfortable, and

the food was exquisite. The chefs

aboard the Des Groseilliers whipped

up lavish Sunday brunches and

hearty meals. The food served its

purpose. The grueling work in frigid

temperatures was physically exhausting, so the researchers and crew

needed to eat well to keep up their

energy levels.

The group also made time for

fun. Liljegren visited with his

counterparts during the ship’s bar

nights and attended a few theme

parties, including a beach party

where he showed off a Hawaiian

shirt he’d brought along. “Everybody that I worked with was really

nice – not just professionally, but

personally,” he says. “All of the

people involved were committed to

making it a good experience.”

At the weekly SHEBA science

meetings, Liljegren listened as his

fellow scientists explained their work

and how the various elements of the

arctic ecosystem worked together.

He gained a greater appreciation for

the way vegetation and animals adapt

to the forbidding environment.

“The Arctic is prolific in terms of

life, although you don’t always notice

it,” he says.

He also managed to find a few

moments of solitude. “Every now

and then in the evenings, I would go

out and just stand on the bow of the

ship and look out because it was so

unique to see the sun shining at

midnight, reflecting off of the melt

ponds. It was amazing, really.”

Liljegren says he was pleased with

the radiometer’s performance at

SHEBA and is looking forward to

analyzing all of the data. “It looks like

it’s going to give us a really useful

picture of the role of polar clouds and

of the radiation transfer through the

atmosphere,” he says. “Everything

worked quite well, so we certainly

have the data to move forward.”

But even as he moves ahead with

his work, he looks back with satisfaction at his time in the Arctic. “It was

a very unique experience being in a

place where almost no one else has

been,” Liljegren says. “Working and

living there for two months was

fantastic.”◆

Melt ponds (left) were common on the

ice; (above) the U.S. Coast Guard’s Polar

Sea carved its way through the ice to

pick up Liljegren and the others.

 1998

12

For more information:

Jim Liljegren, (515) 294-8428

liljegren@ameslab.gov

Current research funded by:

DOE Biological & Environmental Research

Office

Fog and snow frequently shrouded the

 ice pack, making it difficult for scien-

 tists to see the ship from the instrument

 sites – and making it difficult to

spot an approaching polar bear.
 1998

13

SYSTEMS

by Saren Johnston

The experimentalist, Ferdinando Borsa (foreground), and the theorist,

Marshall Luban, examine a sample of manganese 12, a material with

potential applications in the computer industry.

In the furthest stretches of

their imaginations, physicists

never believed they would have

molecular structures in which they

could embed small geometrical

arrangements of interacting

magnetic ions. But now that

chemists have become remarkably

adept at preparing such structures,

physicists have access to the kinds

of uncomplicated systems they

need for investigating magnetism

at the fundamental level.

And, although they may be a

long time coming, the potential

applications for molecular magnetic clusters, especially in the

field of computing technology, are

staggering. Each molecule can be

viewed, in certain cases, as a microscopic magnet with magnetization

that can be oriented up or down,

thus carrying a bit of binary information.

Imagine data-storage capacities

thousands of times greater than what

are available in today’s computer

systems. Magnetic molecular

clusters may one day make it possible to stockpile hundreds of

gigabytes of data in an area equivalent to the head of a pin, an astounding feat when you consider that just

1 gigabyte can store enough information to fill 62,500 typed, doublespaced pages.

Beyond the incredible data

storage possibilities, there also exists

the prospect that these clusters could

be manipulated at the atomic level to

form logic components in a quantum computer. Quantum computers

would operate at speeds hundreds or

thousands of times as fast as the

supercomputers that amaze us today.

Another fascinating, potential

spinoff of the study of magnetic

clusters is the connection with

magnetic molecules that are present

in biological systems and whose

functions are still largely unknown.

But before we look too longingly at

what might eventually develop from

the study of molecular magnetic

clusters, a great deal of fundamental

research must still be done.

In the molecules of interest,

there are as few as 12, 10, six or even

four atoms grouped together, with

each atom having a net magnetic

moment. Because these magnetic

moments arise from the intrinsic

angular momentum, or spin, of the

atomic electrons, physicists frequently refer to the magnetic interactions among “spins.”

Driven by an enthusiastic

curiosity about these systems,

Ferdinando Borsa, an Ames Laboratory senior physicist, is carrying out

nuclear magnetic resonance (NMR)

experiments with certain molecules

to better understand their basic

magnetic properties. NMR uses the

spectroscopic properties of the

energy levels of the magnetic and

quadrapole moments of the nuclei in

strong magnetic fields to obtain

microscopic information about the

atomic magnetic moments, or spins,

in the molecules. This information

may ultimately provide scientists

Simple

Researchers are exploring

the enticing world of molecular magnetic clusters
cal tools are complicated, but you are

aiming at simplicity in physics to get

to the root of the problem.”

The simplicity Borsa requires to

get to the source of magnetic molecule puzzles is supplied primarily by

Dante Gatteschi, a professor of

chemistry at the University of

Florence in Italy. Gatteschi and

members of his research group,

among them the brilliant, young

researcher Alessandro Lascialfari,

produce and characterize the new

materials that provide Borsa the

molecular systems he requires for his

NMR investigations.

Although simple in terms of the

number of interacting magnetic ions,

these molecules are at the same time

complicated, containing lots of

organic materials, such as oxygen,

carbon and hydrogen, which shield

the magnetic moments from outside

interference. “These materials serve

as scaffolding,” says Luban. “They

keep the ions carrying the magnetic

moments positioned as they are. If

you ripped off this stuff, the ions

 1998

14

greater knowledge about the magnetic properties of more complex

materials and make it possible to

design materials with specific

characteristics.

“Teach us Delight in

 simple things.”

Puck of Pook’s Hill, The Children’s Song

 - Rudyard Kipling

The structures Borsa is investigating are unique because, although

the small molecular structures

chemists have designed contain

many different atoms, the magnetic

properties of those molecules are

determined by only a handful of

interacting magnetic ions arranged

in very ordered ways.

“The beautiful thing about these

molecules is that for the first time it’s

possible to control the number of

magnetic moments,” says Borsa.

“You can also control where they are

located in the molecule, their

distance apart and what kind of

interactions take place among these

moments. So these very simple

systems are ideal model systems for

doing theoretical calculations that

are almost exact and can be compared directly to the experimental

data.” Developing analytical theories based on these model systems

should allow scientists to accurately

predict the magnetic properties of

the molecules as a function of

parameters such as temperature and

applied magnetic field.

Marshall Luban, also an Ames

Laboratory senior physicist and a

collaborator with Borsa on the

research, is involved in the theoretical aspects of small magnetic systems. He joyfully notes that the

structures chemists have created in

the laboratory are a theorist’s dream.

“They’re a kind of utopia – simple

systems with just a few interacting

ions as opposed to a number such as

1023 power, which you might

normally worry about,” he says.

“Those kinds of problems are so

difficult that it’s a pleasure to be able

to work on something far simpler,

the other end of the

spectrum in range of

difficulty. What

we’re talking about,

in a sense, are

realizable toy

systems that are

ideal for theoretical

calculations.”

Borsa adds, “In

more complicated

systems, there is a

big gap between the

theories and the

experiments. The

experiments allow

you to get some

information on

magnetic properties,

but when you want

to reproduce that with a theory, you

have to use approximate theories or

use computer simulations on a small

number of particles and extrapolate

the large numbers. With these small

systems, you don’t need to do all

that because you only have six, 10,

20 spins – you can solve the problem exactly.”

Zeehoon Jang, an Ames Lab

graduate student, is doing experimental work on small molecules

with Borsa, but is also intrigued by

the theoretical possibilities that are

Luban’s specialty. He has done

many NMR measurements on small

molecules and worked on some of

the theoretical calculations associated with those molecules.

“Zeehoon is our line of connection

between the experiments and the

theory,” says Borsa.

“Order and simplification are

the first steps toward the mastery of a subject ... ”

The Magic Mountain

 - Thomas Mann

“I think physics is beautiful

when it can be made simple,” says

Borsa. “The logical and mathematiZeehoon Jang is ready to place a sample of manganese 12

in the Bath Cryostat, which will cool the specimen to below

4.2 Kelvin, the temperature of liquid helium, for NMR

analysis. To achieve temperatures below 4.2 K, Jang will

lower the pressure of the liquid helium in the cryostat.
would just wander away.”

Borsa elaborates, comparing a

molecule to a big ball. “The magnetic moments are inside the ball;

they don’t see each other, so the

molecules act independently of one

another. Although you have a

number of these molecules in a

crystal, when you do an experiment,

you’re essentially probing the behavior of one molecule. You

have a repetition of all

units –identical –so you

have the number (n) of

molecules

times the

same result

that you have

for one. But

the advantage of

having

n times

is that you

have big

NMR signals.

“With

NMR, you

use the

nuclei as probes or

spies that are sitting in

the molecules,”

Borsa continues.

“And what the

nuclei see is the

fluctuation of the

spins. So you are studying the

motion of the spins by looking at the

effect on the NMR.”

“Our life is frittered away by

detail. ... Simplify, simplify.”

Walden. II, Where I Lived, and What I

Lived For

- Henry David Thoreau

Some of the molecules that

Borsa, Luban and Jang are investigating include: manganese 12 (Mn12),

iron 6 (Fe6), iron 10 (Fe10), copper

8 (Cu8), copper 6 (Cu6) and, the

latest addition, chromium 4 (Cr4).

That translates to molecules with 12

or fewer spins, and Luban reminds

 1998

15

to say, ‘Yes, we can in fact predict all

of the properties of this system.’ The

applications, I think, will be forthcoming. The more we understand

from these simple systems, the more

we can predict. Then we can start to

get greedy and design systems that

will exhibit the properties we would

like.”

Borsa and Jang hope the NMR

measurements they do on these

various systems will give them a

better idea of how the fundamental

physical law for magnetism determines the magnetic behavior of

interacting spins. “If we can understand that, we may be able to design

a material that will work for better

computer magnetic memory,” says

Jang.

Borsa admits that application is

down the road. Right now, he’s

happy to indulge his curiosity by

using these simple systems to observe

how particles behave when they are

coupled together. “One of the

fundamental problems in condensed

matter physics is what makes many

particles behave in a collective way,”

says Borsa. “Why would a bunch of

particles, when they’re together, have

some new behavior that is not a

direct consequence of the addition of

the behavior of each individual

particle? The hope is to find some

basic law that determines the collective behavior of particles, and then

you can use it in any kind of field.”◆

For more information:

Ferdinando Borsa, (515) 294-9901

borsa@ameslab.gov

Current research

funded by:

DOE Basic Energy Sciences Office

us, “That makes for an enormous

simplification in any effort or

attempt to describe the magnetic

properties of those molecules.”

As an example, he invites us to

look at a diagram of an Fe10 molecule, sometimes called the “ferric

wheel,” because ferric means made

of, containing or derived from iron;

and because the Fe10 structure

diagram closely resembles a

carnival Ferris wheel.

 NMR studies of

Fe10 probe the interactions of the

10 iron ions

under various

conditions to

gain more

information

on the

magnetic

properties of

the molecule.

“Suppose one

of the iron

guys at a

given instant

of time does

something, say

it rocks, rotates

in space or

jumps – it

screams,” says

Luban, anthropomorphizing the iron ions. “Then

we ask the question: ‘If this guy

screams now, at this place, what

impact does it have elsewhere at

these other iron locations at a later

time?’ This is called the equilibrium/time correlation function.”

Because of the simplicity of the

Fe10 system, there’s a good chance

that Luban may be able to calculate

the equilibrium time correlation

function from first principles (i.e.,

without approximations or modeling). He can then directly compare

his predictions about the magnetic

properties of Fe10 with Borsa’s

experimental data. “Hopefully, they

will be in pretty good agreement,”

Luban says. “Then we will be able

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe

Fe10, the “ferric wheel,” is one of the simple

systems that may help physicists discover more

about the collective behavior of particles.
Think back to the lore

of Hercules’ battle with the Hydra

and you’ll understand science’s

frustrating search for a material

that can withstand high temperatures.

The Hydra, a nine-headed

serpent that Hercules was bidden

to slay, was a formidable foe: every

time Hercules cut off one of its

heads, two more would grow to

replace it. Even for a man possessing the incredible strength of

Hercules, it was an exhausting

task.

The mythical battle has

modern-day parallels. Scientists

are searching for a new material

that can withstand temperatures of

up to 1600 C (2900 F). It would

replace steel and other alloys in jet

engines, car motors, furnaces and

turbines, and would allow fuel to

burn hotter and more efficiently.

However, they haven’t found a

material that possesses all of the

necessary attributes. Every time

they try a new material, new

“heads” pop up:

if the material can withstand

high temperatures – pop – it

rusts in the presence of oxygen,

if it doesn’t rust – pop – it sags

at high temperatures, and

if it doesn’t sag or rust – pop –

it melts as the temperatures

climb.

But the battle is far from over.

Scientists across the country have

united behind a material whose

promising properties were discovered at Ames Laboratory. By

surrounding the problem with a

multi-lab effort, they hope to lop

off the remaining heads and slay

the dragon once and for all.

“That’s how research is,” says

Mufit Akinc, an Ames Lab senior

 1997

ceramic engineer and chair of the

Materials Science and Engineering Department at Iowa State

University. “You go one step at a

time.”

Akinc is working

with molybdenumsilicon-boron

(Mo5Si3B), the material at the center of

a five-year project

funded by the

DOE. Participating

scientists from nine

labs, including Ames Laboratory, are trying to work out the

kinks in the intermetallic compound and make it viable as the

high-temperature material of the

future.

Akinc took up his sword in

the battle six years ago when Pat

Thiel, director of the Lab’s

Materials Chemistry Program,

suggested that he take a fresh

look at silicides as a hightemperature material. Silicides

are compounds made of silicon

and other elements. They have

high melting points, but some

silicides are prone to oxidation,

a corrosion process that causes

them to degrade in the presence

of air. Other silicides have poor

creep strength, meaning that

they deform or sag at high

temperatures.

Several decades ago researchers discovered molybdenum

disilicide (MoSi2), which withstands temperatures of more than

1600 C without

oxidizing, but sags

in the intense heat. “It has no

strength at that temperature,”

Akinc says. The material is used

as a heating element in furnaces,

since strength isn’t needed in that

kind of an application.

To work in the next generation of jet engines and other

load-bearing applications, researchers want a material with

oxidative stability and good creep

strength at temperatures of at

least 1400 C (2000 F). “It may

sound very simple, but it’s so

drastic,” Akinc says. “You’re

getting into a temperature regime

where the material becomes

almost white-hot. So far, no one

has been able to get a material

that, at this kind of temperature,

won’t melt, sag or deform, or

oxidize in the presence of air.”

Akinc began working with a

Mo5

Si3 alloy, which had strength

but poor oxidative stability, and

employed a “doping” technique

used by Ames Lab senior chemist

John Corbett. Doping involves

introducing small amounts of a

new element in order to dramati1998

16

Researchers Matt Kramer (left)

and Mufit Akinc

by The Susan Dieterle
1998

cally change the properties of the

original material. Akinc discovered that when Mo5Si3

 is doped

with boron, the oxidation problem is virtually eliminated.

“This material essentially meets

all of the molybdenum disilicide

(MoSi2) performance with

respect to being able to stay

at 1600 C and being able to

resist oxidation, but it’s at

least 10 to 100 times more

resistant to deformation,” he

says.

As he continued investigating Mo5Si3B with the help of

former graduate students Mitch

Meyer and Andy Thom, word

about his work began to

spread. One of the students

approached Matt Kramer,

assistant program director for

Metallurgy and Ceramics, for

help in understanding the

deformation processes affecting

the alloy. Kramer was intrigued by the material’s properties and began doing some

microstructural characterization work.

The material’s properties

also caught the attention of

associate metallurgist Bruce

Cook and associate ceramist

Ozer Unal. Cook is measuring

the electrical properties of the

material, while Unal is concentrating on its mechanical

properties.

Scientists throughout the

nation also were interested. Last

year the Ames Lab group received

a three-year, $900,000 grant

from DOE’s Advanced Energy

Projects Division to continue

work on the molybdenumsilicon-boron material.

In 1996, DOE wanted to

select a high-temperature intermetallic substance for a five-year,

multi-lab study. “They wanted

something that would leapfrog

the current technology, not

something that just moved it

ahead in small increments,” says

Kramer, who presented the

proposal from Ames Lab suggesting Mo5Si3B for the project.

Other materials that were

discussed included ironaluminides and nickelaluminides. “Most of the ironand nickel-aluminides had a

maximum operating temperature

of 800 C to 1000 C,” Kramer

says. “We had already pushed

the molybdenum material to

almost 1400 C, so this fit very

well with what the DOE was

looking for.”

The molybdenum-siliconboron material was selected for

the Design and Synthesis of

Ultrahigh Temperature Intermetallics Project. DOE is dividing

17

To avoid contamination, pellets of the

silicide material are studied in the

oxygen-free atmosphere of a glove box.

$300,000 a year among the eight

participating national labs – Ames

Lab, Argonne, INEEL, Lawrence

Berkeley, Lawrence Livermore, Los

Alamos, Oak Ridge and Sandia –

and the University of Illinois. The

funding is helping to redirect

research efforts toward Akinc’s

material and to stimulate collaborative efforts among the 25 scientists involved in the project.

The two project coordinators

are R. Bruce Thompson, director

of Ames Lab’s Nondestructive

Evaluation Program, and Roddie

Judkins, manager of the Fossil

Energy Program at Oak Ridge.

Thompson, who also directs

Iowa State’s Center for

Nondestructive Evaluation, says that even

though the project is in

its early stages, it is

already generating a lot

of excitement in several

scientific disciplines.

“There’s a tremendous

amount of interest in

this material and the

questions it opens up,

both scientifically and

technically. Given the

creative talents of the

scientists involved, that

should lead to something quite useful,” he

says.

Judkins notes that use of the

molybdenum material could help

the environment. If the operating

efficiency of turbines and engines

improves, less fuel would be

needed to generate the same

amount of power. Using less fuel

would also cut the amount of

emissions and “greenhouse gases”

in the atmosphere, thereby reducing the threat of global warming.
1998

18

labs doing the work on this. We’ve

got a lot of good science in this

investigation. That’s

one reason I

think it will

be successful.”

Aside

from the

work on the

material

itself,

Kramer says

the multilab effort

represents

an enormous

achievement. “One

of the

objectives of

the project

is to get the labs to work together,

and regardless of whether the

project works or doesn’t work in

terms of the technology, it really

has helped the collaborative research,” he says.

 Akinc believes this kind of

unified effort is the best hope for

slaying the high-temperature beast.

“It takes perhaps one person to see

an opportunity, but it takes a large

team of scientists with different

backgrounds to turn it into a

reality,” he says. “That’s what we’re

doing.”

With that upbeat attitude,

“heads” are sure to roll.◆

For more information:

Mufit Akinc, (515) 294-0744

makinc@ameslab.gov

Matt Kramer, (515) 294-0981

mjkramer@ameslab.gov

Akinc tests the mettle of the intermetallic compound in furnaces that

reach temperatures of 1700 C.

Current research funded by:

DOE Basic Energy Sciences Office

“I think this project clearly falls

under the category of public-good

R&D, and the public good

derived from this is energy security and an improved environment,” Judkins says.

Even though the molybdenum-silicon compound represents

a large step forward in the search

for a new high-temperature

material, several problems remain.

Mo5Si3B, like many other

high-temperature intermetallic

compounds, is extremely brittle at

room temperature. “It’s not a

very tough material,” Akinc says.

“You can hammer steel and it

won’t do any damage, but if you

put this material at an angle and

whack at it, you can break it. You

don’t want that to happen to an

airplane engine.”

It’s also difficult to process.

“Processing means you have to

synthesize the materials and turn

them into certain shapes. This

material is extremely difficult to

deform at high temperatures and

has great strength,” Akinc says.

“That’s good, but not if you’re

trying to shape it.”

That’s not all. “In order to

cast the material from the molten

state, you need to heat it to 2200

C,” he says. “How do you melt it

and where do you melt it? And

how do you pour it into a mold

that will withstand that kind of

temperature? These are the

problems we need to work out.”

The DOE labs are tackling

different aspects of those problems, and the researchers hope

their combined efforts will make

the material viable. “We’re

making significant progress in a

relatively short amount of time,”

Judkins says. “We have some of

the best people at some of the best

“ ...the public good derived from this is energy

security and an improved environment.”
ERS

a case

Scalable Computing Lab (SCL) are

determined to make traditionally

expensive supercomputing capabilities

more economical and attainable for

scientific and educational communities.

Playing an intriguing game of

“workstation upset,” Gordon and SCL

researchers David Halstead, John

Gustafson, Stephen Elbert, Don Heller,

Dave Turner, and Bruce Harmon are

dumping the traditional concept of

boxed-system supercomputers. Incorporating the option to grow, or scale up,

they are taking computing power out of

the box and spreading it over networks

of personal computers (PCs), creating

clusters that operate at speeds comparable to today’s best parallel computers,

and for a fraction of the cost.

 Parallel computers are like valued

employees: they can handle a number

of tasks at the same time. Their multiple processors work simultaneously on

different parts of a single problem,

making them far more efficient and able

to handle more complex problems than

sequential computers, which tackle

problems one step at a time.

One of the ways the SCL team

19

 1998

Until very recently,

parallel computing came in a

box – an incredibly expensive one.

Inside a boxed system is an activity

center comprised of anywhere from

several to many thousand central

processing units (CPUs) that interpret

data and execute instructions. It’s like

packing the processing power of a

whole warehouse of computers into a

shipping crate. What you get is a

supercomputer, but that much power

comes at an outrageous price.

Just one such boxed system can

cost millions of dollars, and what if

one or two CPUs go bad? How do

you fix a supercomputer? Mark

Gordon, Ames Lab program director

for Applied Mathematics and Computational Sciences, explains the reality of

supercomputer repair. “You pay the

manufacturer 10 to 20 percent of the

purchase price each year for maintenance,” he says. “You can’t get them

fixed anywhere else.”

Out of the box

But high-performance parallel

computing doesn’t have to cost a

fortune. Gordon and several of his

colleagues at Ames Laboratory’s

David Halstead (standing) and Mark Gordon are working to

improve the communications among personal computers in

network clusters. Their efforts are helping to make parallel

computing power available for greatly reduced costs.

for

 Supercomputing

by Way of

Personal

Computer

Networks

by Saren Johnston

Achieving parallel power with

networks of personal computers

requires connections on top of

connections, and all correctly made. a case

Achieving parallel power with

networks of personal computers

requires connections on top of

connections, and all correctly made.

CLUSTERS
How many shelves does it take to hold the 64-

node ALICE cluster? Four in a tidy diagram,

but a few more in the lab.

hopes to make parallel

computing more

economical is by

devising a “cluster

cookbook” for the world

wide web, which will

provide guidelines on

how to construct PC

clusters. Team members

also plan to develop and

host a hands-on workshop that will help bring

the cost-saving cluster

computing technique

into university departments, individual

research groups and the

classroom.

The cluster craze

“What precipitated

the clustering effort is

that in the last few years

manufacturers of personal computers

have been making them with speeds

that are equivalent to workstations,”

says Gordon. “This means that you

can take these computers as individual

units and use them for really highperformance computing in a sequential sense. You can put on one $3,000

personal computer what you used to

put on a high-performance workstation, and it will perform just as well

for you.

“What’s hard is going the next

step: networking clusters of these PCs

to make a true, parallel, high-performance computer that’s competitive

with boxed systems that cost millions

of dollars,” Gordon says.

 Gordon and his colleagues have

made that intricate job look easy. “It’s

clear that small clusters work, small

being eight,” he says. “We have a

math cluster with eight nodes running

partial differential equations. And all

of our quantum chemistry codes can

run in parallel.” Gordon adds that in

other areas of the Lab, clusters of eight

PCs are doing materials simulations

and modeling new materials with

desirable magnetic properties. “So the

 1998

20

Dunning, Battelle

Fellow in Computational Sciences at

Pacific Northwest

National Laboratory. “And that’s

one of the major

problems they’re

looking at here at Ames Lab. So

they’re tackling what is probably the

most significant problem in realizing

the potential that PC clusters have.”

Configuration also has a lot to do

with how well large networks of PC

clusters perform. “Imagine having 64

PCs,” says Gordon. “You can arrange

them in lots of different ways, and the

further one computer has to go to

communicate with another, the more

arrangements you have. So there’s a

traffic-directing problem to deal with.”

In addition, Halstead reminds us

“Cluster computing is a

happy synchronization of

technologies.”

Each personal

computer in the SCL’s

64-node cluster

contains two central

processing units,

making a powerful

system of 128

processors.

9Gdisk 9Gdisk

100Mbit fiber connection to Cisco 7513 router

Server Compile node

Spare

Cajun P550

Gigabit fiber connection to other SCL clusters

Dev1 Dev2 Dev3 Dev4

Development

Nodes

64 node/128 processor Ames Lab/ISU Cluster Environment

issue is, does clustering work

when you scale up to 64? Does it

work when you scale up to 128?

That’s really unknown.”

 Reality check

Whether larger networks of

PC clusters will work depends to

a great extent on how well researchers

can optimize message-passing between

the various computers in a cluster.

The communications system currently

in use is called gigabit, which is

supposed to be several times faster

than previous systems. But the

performance has not matched the

prediction. So part of the SCL team’s

research is to determine how best to

optimize gigabit.

“The Achilles’ heel of PC clusters

in the past has been the communications capabilities,” says Thom
“At the end of the day, this thing

should be four times as fast and have

four times the storage capacity and

memory as the largest supercomputer

in the SCL, which cost just shy of a

million dollars,” says Halstead. “So it’s

four times as fast for a third of the

price.”

The SCL researchers have compared the performance of their clusters

with that of commercial parallel

computers by using a computer

benchmark called HINT, which

Gustafson developed and for which he

earned an R&D 100 Award in 1995.

“I think HINT is better than just

about any other way of benchmarking

computers,” says Gordon. “If you take

John Gustafson’s method and evaluate

our clusters against one of the best

parallel computers on the market

today and then go the next step and

divide that by the cost to get the price/

performance ratio, the clusters blow

everything else away. And that’s our

point – not to show people how to do

really great parallel computing because

lots of people can do that, but to show

them how they can do it in a very costeffective way.”◆

For more information:

Mark Gordon, (515) 294-0452

gordon@ameslab.gov

David Halstead, (515) 294-1943

halstead@ameslab.gov

Current research funded by:

DOE Basic Energy Sciences Office

of the obvious issue. “There’s a

definite storage concern for a large

cluster network. Where do you put

the thing? Also, all the energy that

goes into a computer comes out as

heat, so you’ll use more power for air

conditioning.”

Cluster luster

SCL researchers believe the

potential benefits of scalable cluster

computing far outshine the issues they

are working to resolve. A big advantage of taking the cluster path to

parallel computing is that you can

always reconfigure the system to meet

the needs of the day. For instance,

instead of having a 128-node computer, you might choose to have two

64-node computers. “You can set

these things up as a computer lab,

launch them to run a word processing

program for a class, and reboot them

to run as a single parallel computer,”

says Halstead. “You can trade off with

other departments – whatever you

want to do. With this kind of sharing

of resources, you’re only really limited

by curriculum originality.”

Halstead also notes that although

PC clusters are not meant to replace

the powerful supercomputers that

operate at Department of Energy

national labs, they can lessen the

computing burden placed upon these

machines and so reduce the barrier to

national computer use.

Dunning explains, “The bigger

systems are very full – they’re oversubscribed because far too often we go to

the big machines to solve routine

problems. We’re not taking advantage

of the economics that could come if

we had tiers of computing capability

designed for specific tasks. I see PC

clusters as being very effective at

satisfying an intermediate set of

demands that would then free up the

big supercomputers to do the job that

they are really intended to do, which is

the very high-end computing.”

Without a doubt, however, the

biggest advantage of PC clusters is

 1998

21

their low cost.

“Cluster computing is a happy

synchronization of technologies,” says

Halstead. “If a PC dies, you throw it

away and go down and buy another

one, kind of like replacing a fan belt.

The beauty is if a particular PC is not

needed in a cluster, it’s still a very

powerful desktop machine. We’re not

buying into a hardware technology

that in a year’s time will be completely

useless due to lack of software support.”

Maybe the answer to whether

clusters will work when scaled up to

larger and larger systems will come

soon. The SCL team recently constructed a cluster of 64 PCs, each with

two central processing units, and is

now testing its ability to perform

parallel computations.

Halstead has high praise for the

ISU students employed by the SCL,

noting that the cluster, fondly named

ALICE (Ames Lab/ISU Cluster

Environment), was made possible by

their extensive knowledge of the

operating system and network communication protocols. The students

include Vasily Lewis, Brian Smith,

Chris Csanady, Stephanie Holeman

and Chris Williams. “Vasily was

responsible for the design and implementation of the ALICE compute

node, the ease of which is essential to

the project,” Halstead says. “And

Brian produced a cluster monitoring

tool that allows the status of the

cluster to be ascertained using a web

browser. The talents of the entire

student group were invaluable in

addressing the difficult issue of

configuring 64 PCs so that they act as

a single computer.

“So it’s

four times

as fast for

 a third of the price.”
scopic analysis in the laboratory.

Thin samples are necessary to obtain

useful spectra for analysis. If it

sounds like a labor intensive, lengthy,

and costly process – one that slows

down the type of quality control

necessary in the paper-making

process – it is. “Of course, anytime

you have to go off-line and into the

laboratory, the measurement process

becomes much slower and more

expensive,” Jones says.

 Whereas current technology is

slow and cumbersome, the TIRS

technique is fast and efficient,

providing on-line analysis. TIRS

actually takes advantage of the fact

that the material, whatever it is, is

moving down the process line. “The

material has to be moving in order

for TIRS to work,” says McClelland.

TIRS can’t actually make a thick

material thin, but it can trick the

infrared spectrometer into

thinking that’s the case. To do

so, Jones reduces absorption

On this day there are six large

white boxes stacked neatly along

the wall of Roger Jones’ laboratory.

The boxes each contain several

bags of wood chips from Douglas

Fir trees. Each of the chips ranges

in size from approximately an inch

to an inch and a half long to about

an inch wide. Altogether there are

thousands, perhaps hundreds of

thousands of wood chips in the

boxes, which have been shipped to

Jones by the Weyerhaeuser Paper

Company, an industry giant in the

making of paper and paper products.

Weyerhaeuser has supplied the

wood chips as part of a three-year

research project in which Ames

Laboratory scientists are participating to improve paper-industry

techniques for analyzing the major

components of timber harvested

from forests across America.

The Ames Lab research revolves

around the use

of Transient Infrared Spectroscopy,

or TIRS, which was invented by

Jones, an Ames Laboratory associate

chemist, and Ames Lab physicist

John McClelland. TIRS relies on

spectroscopy, the art of analyzing

substances by measuring the radiant

(light or heat) energy their molecules

either emit or absorb and then

interpreting the resulting electromagnetic spectra.

The on-line, real-time

advantage

Today manufacturers are most

interested in the mid-infrared (midIR) portion of the spectrum (400 to

4000 cm-1), which contains an

abundance of information about a

material’s molecular and chemical

makeup. But solids, like wood chips,

aren’t popular in the mid-IR because

they are thick and absorb infrared

radiation. So in order to perform

spectroscopic analysis of wood chips

or other materials in the mid-IR

region, technicians are forced to

remove samples of the materials

randomly from the process line,

prepare thin or diluted

specimens from the

samples and

then conduct

the spectroWood chips of various shapes

and sizes are being analyzed by

TIRS for the paper industry.

Wood chips of various shapes

and sizes are being analyzed by

TIRS for the paper industry.

John McClelland (left) and Roger Jones say the

TIRS technology provides more detailed information

than other analysis techniques being considered for

use by the paper industry.

by Steve Karsjen

 1998

22
infrared specrometer

hot air

moving material moving material

 1998

23

by inducing a temperature transient

in the moving surface of the wood

chips as they move by on their way to

the digestor that feeds into the paper

machine. Gas jets blowing on the

material temporarily create a very

thin hot or cold layer at the surface

of the material without physically

thinning it. The mid-IR spectrum of

the thin layer can then be measured

by an infrared spectrometer.

Around and around

it goes

With a laboratory model of a

wood chip process line, Jones demonstrates the TIRS technique by

placing wood chips on a large circular

plate, which looks a lot like an

oversized pizza pan. The chips are

piled up along the outer edge of the

plate and rotate with it as the plate

spins around and around. At one

point in the rotation, the chips come

in contact with a hot blast of air from

a gas jet, which strikes the surface of

the chips, heating them. As the

wood chips rotate through the field

of view of an infrared spectrometer,

the spectrometer measures the

electromagnetic spectra of the heated

sample. In Jones’ experiment, the

spectra being measured come from

one of the major components of

wood, lignin, the material that turns

paper brittle and yellow over time.

Low quality paper, like newsprint,

contains a lot of lignin while most of

the lignin is removed from highquality paper. “By keeping track of

how much lignin the wood contains,

technicians control the quality of the

paper they’re producing,” says Jones.

In addition to its on-line capabilities, TIRS conducts its analysis in

real-time. “This is actually the most

important aspect of TIRS,” says

McClelland. “Real-time measurement allows you to get data immediately so you can make adjustments

that improve the quality of the paper

on-line.”

A few bumps along

the way

Jones had a pretty good idea

TIRS would provide the type of

analysis the paper industry needs.

Since its invention, the TIRS technology has been successfully used to

analyze over a hundred materials

from plastics to coal and corn. All of

these samples were smooth, however,

which is a far cry from the rough,

irregular-shaped wood chip samples

provided by the paper industry.

There was also a question of whether

the TIRS technology would work

across tree species (hardwoods and

softwoods) and on trees from all

regions of the country. “Our model

contains over a dozen species at this

time,” says Jones. “So far they haven’t

thrown anything at us that we haven’t

been able to analyze.”

Where do we go from

here?

Although Jones says initial

feedback from the paper industry on

TIRS has been “good,” he’ll have a

better feel for whether it will be

effective when an actual field test is

conducted. Other analysis techniques are also being considered by

the paper industry at this time,

which, McClelland admits, may

actually prove to be better fits than

TIRS.

“If that’s the case, then there may

be additional aspects of the papermaking process that can benefit from

the TIRS technology,” says a confident McClelland, who adds that

instead of using TIRS to analyze

wood chips as they are going into the

paper digestor, it might be better to

conduct the TIRS analysis at the

other end of the production process,

where the paper is being manufactured by the paper machine. “We’re

already conducting tests on different

paper coatings and paper processes to

see how well our technique works,”

says McClelland.

And beyond the paper manufacturing-industry, McClelland and

Jones are looking at adapting TIRS

to meet specific needs of the glass

industry. “We have a proposal to

analyze the ‘cure’ of coatings on fiber

optic cables,” says McClelland. If

not properly cured, the cables stick

together and the coatings tear as the

cables are being unwound from

spools. “This amounts to a multimillion dollar problem for this

industry,” says McClelland, “and we

hope there might be an opportunity

for TIRS to also have some impact in

this area.”◆

For more information:

Roger Jones, (515) 294-3894

jonesrw@ameslab.gov

John McClelland, (515) 294-7948

mcclelland@ameslab.gov

Current research funded by:

DOE Energy Efficiency and Renewable

Energy Office
 Ames Lab Director Tom Barton traveled to Washington,

D.C., in May to witness the signing of a memorandum of agreement with the FBI and the Justice Department that will allow Lab

scientists to tackle research for the FBI.

 The FBI will draw upon the Lab’s expertise in analytical

methods and instrumentation development to help advance the

frontier in forensic science. The FBI Laboratories make up the

largest forensic science facility in the world. Scientists there are

especially interested in portable and miniature analytical instrumentation for DNA, drug, gunshot and explosive residues analyses; and analysis of materials after a disaster or criminal/terrorist

act.

 Proposals for projects the FBI would like Ames

Lab to investigate have been submitted for

funding. According to Barton, an

example of one of the

things the Lab would

do for the FBI is work

on new techniques for

analyzing serial numbers

that have been ground off

various items.

Lab to Work with FBI

 A crackerjack student

team from Valley High

School in West Des

Moines, IA, won the

Department of Energy’s

1998 National Science

Bowl in Washington,

D.C., in May. Valley

progressed to the national competition after

winning the Ames

Laboratory regional competition in February.

The science whiz-kids triumphed over 47 teams to capture

the national championship. The Valley team received an allexpenses-paid trip to Lindau, Germany, to meet with Nobel

Laureates in chemistry. During the one-week trip, they also

attended a symposium with scholars from around the world.

INtouch

Iowa-Grown Science Champs

 The Department of Energy

has recognized Ames Lab researchers

Karl Gschneidner (above) and Vitalij

Pecharsky for their contribution to

the advancement of magnetic refrigeration technology.

The two scientists were

awarded the

1997 Materials

Sciences Award

for Significant Implication for

Department of Energy Related

Technologies in the Metallurgy and

Ceramics category.

Gschneidner and Pecharsky

discovered the giant magnetocaloric

effect in gadolinium-silicon-germanium (GdSiGe) alloys, which are

destined to boost the cooling power

and efficiency of magnetic refrigerators. The magnetocaloric effect is the

tendency of some metals to become

hot when magnetized and cool down

when demagnetized.

The high magnetocaloric effect

of GdSiGe alloys not only improves

the efficiency of large-scale magnetic

refrigerators, making them even more

competitive with conventional gascompression technology, but may

also lead to small-scale applications

that include climate control in cars

and homes, and in home refrigerators

and freezers.

Ames Lab Wins DOE

Award

for

Pretty Cool

Stuff

 1998

24