In 1988, Ed Yeung, director of Ames Laboratory's Environmental Sciences Program, set the goal of characterizing the chemistry of a single human red blood cell. No one could have accused him of setting his sights too low.
The typical red blood cell has a volume of only 86 femtoliters, or a few millionths of a billionth of a liter; it takes roughly half a billion cells to make up one drop of blood. Yet within this minute package there are thousands of different compounds, many of them present in only trace or ultratrace amounts. In a day and age when the nanoscale has become banal and even the picoscale has lost its charm, the red blood cell allows analytical chemists to test their stuff at the still smaller femtoscale, attoscale and zeptoscale.
But the truly hard part, from the analyst's point of view, is that very few cellular compounds have properties that lend themselves to detection. "It took three years even to develop the first technique sensitive enough to detect anything in the red blood cell," Yeung remarks wryly.
In the three years since that breakthrough, however, Yeung, who is also a distinguished professor of chemistry at Iowa State University (ISU), and a series of ISU graduate students have developed many ingenious techniques for analyzing the contents of the red blood cell. Among the compounds they have been able to detect are particularly efficient forms of an enzyme present at elevated levels in colon cancer, breast cancer, liver cancer and leukemia. But Yeung points out, "Because we are working with human blood cells, we can assume that anything we can see will be of some kind of interest."
Even more important than any particular research result, in Yeung's opinion, is the rethinking of biochemistry that occurs when it is possible to analyze events in a single cell. "The average income of Americans is about $23,000," Yeung explains, "but that's not very interesting. What you really want to know is how rich Donald Trump is and how poor the homeless are and what the guy down the hall makes. That's what we're trying to do. We don't want to get the average; we want to look at the values in individual cells. After all, cells are true entities; each is a distinct materials system."
All of Yeung's techniques employ the microfluor detector, an instrument he developed. In the microfluor detector, the contents of the cell flow through a transparent capillary. A laser beam illuminates a section of the capillary, causing some compounds to emit light, or fluoresce. A computer then analyzes the color of the light to determine the identity of the compounds.
The microfluor detector clearly had the sensitivity needed to decipher the red blood cell's chemistry, but there was a hitch. It detected target compounds by inducing them to fluoresce, and most biological compounds either do not fluoresce or fluoresce weakly.
One solution, which Yeung found with the help of graduate student Barry Hogan, was to attach a tag to a target molecule to make a strongly fluorescing compound, much as a private detective might stick a homing device to the underside of a car to make it easier to follow in traffic. The target molecule was glutathione, a peptide thought to play a role in repairing cellular damage caused by reactions with oxygen and other oxidizing substances.
Tagging may sound like a perfect solution to the analytical problem, and indeed it worked well for glutathione, but it isn't generally useful. The problem is that the reaction between the tag and the target may not go to completion, which means there may be targets in the cell the detector cannot see. Worse yet, the reaction might be 80 percent complete in one cell and 90 percent complete in the next cell, rendering invalid the cell-to-cell comparisons that are the goal of the analysis.
The next strategy, devised by Hogan, Yeung and graduate student Qingbo Li, was the paradoxical one of detecting a target compound by the absence of fluorescence. For these experiments, the buffer solution that washed over the cell's contents as they were drawn through the separating capillary was chosen to produce a large fluorescence signal. Cellular substances such as sodium and potassium ions could then be detected by the dip in the signal that occurred as they passed in front of the laser, much as you might detect a person standing behind you by the shadow he or she cast.
Although the team was eventually able to measure the amounts of sodium and potassium in individual red blood cells with confidence, indirect detection proved difficult. "There was an art to it that we had to learn before we could get good results," says Yeung.
Some of the most interesting compounds in the cell are proteins. Like glutathione, proteins can be tagged, but the tagging reaction might not go to completion. Moreover, the tag might attach at several different sites along the protein so that the molecules produced by the reaction might have various numbers of tags.
Proteins are weakly fluorescent, and Yeung and graduate student Thomas Lee found that in some cases they were able to avoid the problems associated with tagging by looking for this "native" fluorescence. One of the proteins they were able to detect in this way was hemoglobin Ao, the major form of hemoglobin in adults.
Hemoglobin, the signature molecule of the red blood cell, is relatively abundant, but most of the proteins in the cell are present in only trace amounts. For every protein that is present in attomole concentrations, there are hundreds present in zeptomole concentrations. At those low concentrations, the sheer number of compounds becomes an obstacle to analysis. Trying to zero in on a zeptomole protein is like looking for a contact lens in a bin of ice chips.
Yeung and graduate student Qifeng Xue came up with a clever way around this problem that works for enzymes or other cellular catalysts. Catalysts have the useful property of repeatedly participating in reactions without themselves being consumed. One enzyme molecule, for example, can make hundreds or thousands of product molecules per second. Yeung and Xue's idea was to look not for the enzyme but rather for the much more abundant product the enzyme was cranking out.
They chose lactate dehydrogenase, one of the enzymes involved in the anaerobic metabolism of glucose. Yeung and Xue were ultimately able to detect five isoforms, or varieties, of lactate dehydrogenase. The levels of the fourth and fifth isoforms (LDH-4 and LDH-5) are elevated in cancer cells, perhaps because these forms are more efficient than the others, and efficiency is at a premium in these metabolically active cells. Now that they can be reliably measured, LDH-4 and LDH-5 levels may prove useful for early diagnosis of cancer.
Yeung and Zeev Rosenzweig, a postdoctoral fellow, devised a second, equally clever method for detecting zeptomole proteins. Latex particles mixed with a cell's contents during analysis can be detected by the laser light they scatter. If the particles are coated with an antibody to a target compound, the target will stick to them, form larger clumps and create bigger scattering peaks. This technique was used to detect the enzyme glucose-6-phosphate dehydrogenase, which also plays a role in the metabolism of carbohydrates.
Yeung isn't finished with the red blood cell yet, but he and his team are already applying the techniques honed on this cell to two other types of cell: the white blood cell, which is of interest because of the central role it plays in fighting disease; and the adrenal cell, which serves as a model of the nerve cell.
"The goal in the adrenal cell is to see whether we can follow nerve impulses by identifying the chemicals that carry them," says Yeung. Happily, many of the major neurotransmitters - among them serotonin, epinephrine and norepinephrine - are weakly fluorescent. "If you were to present the molecular structure to a good spectroscopist," Yeung remarks, "he or she would recognize it to be a fluorescing molecule. But I don't think anyone has actually used the fluorescence of these compounds for sensitive detection.
"We're the only ones using native fluorescence of proteins in single cells, the only ones using indirect detection, the only ones using the latex-particle assay and the only ones doing the enzyme assay," Yeung says. "Now we're the only ones using the native fluorescence of neurotransmitters."
Jonathan V. Sweedler of the department of chemistry and the Beckman Institute at the University of Illinois at Urbana-Champaign comments, "Ed Yeung has developed the most complete chemical methodology available for studying a single cell. In doing so he has significantly advanced the state-of-the-art in small-volume, ultratrace analytical methods. The red-blood-cell work is a real tour de force of the spectroscopic art."
For more information:
1. "Chemical Analysis of Single Human Erythrocytes," Edward S. Yeung, Accounts of Chemical Research, 27 (1994) 409-414.
2. "Variability of Intracellular Lactate Dehydrogenase Isoenzymes in Single Human Erythrocytes," Qifeng Xue and Edward S. Yeung, Analytical Chemistry, 66 (1994) 1175-1178.
When Bill McCallum and Dan Branagan began their experiment to add a distinctly separate phase to the neodymium-iron-boron system, they didn't know what to expect. They were considering the addition of materials called refractory metal carbides to the Nd2Fe14B system that might either completely trash the alloy or stabilize its microstructure, making it more resistant to grain growth and allowing for stronger permanent magnets.
For those who work in the world of permanent magnets, small grains are the big attraction. "Obtaining the correct metallurgical grain size of 20 to 100 nanometers is crucial to forming a permanent magnet," says Branagan, a graduate assistant in the Lab's Metallurgy and Ceramics Program. "Larger grain sizes drastically diminish the strength of the magnet."
To achieve the appropriate grain size, McCallum and Branagan use a rapid solidification process called melt spinning, which McCallum, a Lab senior metallurgist, describes as a fairly simple process. The procedure involves putting a jet of liquid metal down on a swiftly spinning copper wheel. "The wheel's angular momentum can be transferred to the liquid metal only a little bit at a time, so you drag out a thin film," says McCallum. "The process is similar to the way water gets dragged along on your car tires when you hydroplane going 60 miles per hour down the freeway."
Because the film of liquid metal is very thin, heat is pulled out of it extremely rapidly. The thermal conductivity of the spinning wheel causes the liquid alloy to solidify in ribbon form almost instantaneously. Thermal contraction then causes pieces of solidified ribbon, approximately 2.5 centimeters in length, to fly off the wheel into a collection chamber.
The attributes of the ribbon depend on the rate at which the liquid is cooled. At faster wheel speeds, the liquid cools rapidly; there isn't time for rearrangement of atoms or molecules. The melt-spun ribbons form a metallic glass similar to window glass. This metallic glass, called an amorphous material, has the same structure as the liquid material. It is denser, but it has no grain boundaries. At slower speeds, the liquid cools less rapidly and crystallization occurs. The ribbons form with a very fine dispersion of crystallites, or grains, of optimum size.
Although the rapidly solidified material that McCallum and Branagan produce using the melt-spinning process exhibits the desired grain size, the small ribbons of material are not useful magnets. "You have to consolidate the ribbons into a dense chunk of material, and the best way to do that is to use a technique called hot deformation processing," says McCallum. "But if we try to process the material this way, the grains grow and we lose the desirable microstructure. So the reason we started this project was to determine what we could do to maintain the microstructure and prevent grain growth at high temperatures where one can do consolidations.
"What you do, essentially, is put stuff on the grain boundaries," McCallum continues. "The catch is that we have to have a special kind of stuff that has nice properties and that in and of itself does not have a tendency to grow very rapidly. We have to be able to put this material down in a very fine dispersion around grain boundaries and where the grains are submicron."
McCallum says scientists have experimented with additions to the Nd2Fe14B system, but those additions were basically single-element substitutions.
"The approach we took was to say, `OK, let's look at what happens if we select a material that will form a compound when added to the Nd2Fe14B system,'" says McCallum. "We were looking for things that are very stable, and the most stable things in the world are compounds."
The most stable compounds for the complicated Nd2Fe14B system as a whole turned out to be refractory metal carbides. So Branagan began the lengthy task of studying them individually to determine which one would have the best effect when added to the permanent-magnet alloy during the melt-spinning process.
Branagan's work showed that the refractory metal carbide of choice was titanium carbide. "Titanium carbide has one of the highest melting points and one of the highest free energies of formation, so there was a good indication that it would work," he explains. "Titanium and carbon prefer to combine together rather than with the neodymium, iron or boron elements in the alloy, which prevents them from reacting with the magnet material and damaging the microstructure."
McCallum and Branagan had found the correct refractory metal carbide, but it had been a bold step to take. "When we started this project, we said, `Let's try to put in a distinctly separate phase,'" McCallum recalls. "Now, this is a risky step because you never know what might happen. The differences as you go across a series on the periodic table, starting with titanium, moving over to vanadium, moving over to chromium, are quite small. Yet when we tried putting each one into the permanent-magnet material, there was a difference between working very well on the titanium end and completely destroying the system on the chromium end.
"Dan has shown that it's the titanium going into the melt that gives us the ability to produce a metallic glass," McCallum continues. "But added by itself, the titanium steals the boron, pulling it away from the Nd2Fe14B melt and entirely changing the phases we get out when we solidify the material." To counteract this effect, McCallum and Branagan add both titanium and carbon elements to the melt at the same time.
"The addition of these elements gives us this very fine dispersion of the titanium carbide phase, and that stabilizes the grain structure that we desire for magnetic properties," says McCallum. "Dan has produced a very nice two-phase microstructure, and that means permanent magnets that provide more energy than would be possible with a single-phase structure."
McCallum and Branagan's research paid off in terms of satisfying their original goals, but unexpectedly, it also provided a bonus. "The bonus is that when the titanium and the carbon go into the melt, they affect the properties of the liquid drastically," says McCallum. What that does, he explains, is reduce by a factor of three the wheel velocity necessary to get an amorphous material, which also means that it reduces by a similar factor the wheel velocity necessary to get a particular microstructure.
"Now, what's the importance of this?" asks McCallum. "We now have the ability, in some sense, to tailor the characteristics of our melt to what can be achieved in melt spinning and other rapid solidification processes as well." McCallum explains that lower cooling rates in processes such as high pressure gas atomization (see Inquiry, Spring 1991) often result in smaller fractions of the permanent-magnet material being cooled quickly enough to form the optimum microstructure.
"If you make a big batch of material and you can only use 10 percent of it, that's not a commercially viable process. However, by putting in the titanium carbide, you open that window up and can use a much larger fraction of the material," McCallum says. "That means that using these new alloys results in less scrap being produced. So the additions have a real significance. The bonus may be of more interest and more importance than the original idea."
For more information:
1. "Solubility of Ti with C in the Nd2Fe14B System and Controlled Carbide Precipitation," D. J. Branagan and R. W. McCallum, Journal of Alloys and Compounds (1995) in press.
2. "Altering the Cooling Rate Dependance of Phase Formation During Rapid Solidification in the Nd2Fe14B System," D. J. Branagan and R. W. McCallum, Journal of Magnetism and Magnetic Materials (1995) in press.
One afternoon early in 1995 at the Aladdin storage ring in Stoughton, WI, the announcement, "the lamp is lit," will come over the public-address system, alerting scientists that a beam of electrons has been successfully injected into the ring.
A little later Ames Laboratory Senior Physicist Clifford Olson will turn on the electromagnets of a device called an undulator in the electrons' path. He will then open the main valve to a vacuum pipeline that streaks off at a tangent to the ring. Downstream from the valve, a small rod will advance into the pipeline and tap a fixture holding a minute sample of a nondescript gray material, cleaving it neatly in two. Light shaken out of the electrons by the undulator will hit the pristine surface of the material, knocking out thousands of electrons, a select few of which will pass through the opening of a nearby detector.
Several hours of tweaking and tuning later, Olson will begin collecting the data that may one day help answer a question that has been tying theoretical physicists in knots for the past five years: Why do high-temperature superconductors conduct electricity with no resistance at such convenient temperatures?
Olson and David Lynch, an Ames Lab senior physicist and a distinguished professor of physics at Iowa State University (ISU), hope to measure the size of the superconducting gap in these new materials far more accurately than it has ever been measured before. (The gap is a zone of forbidden states that opens up when the material loses its electrical resistance.) If the past is any guide, their measurement will become a rock of experimental fact on which the many theoretical physicists trying to understand these materials will subsequently stub their toes. So high does the physicists' reputation stand and so important is this experiment considered that the National Science Foundation and ISU funded the construction of a beamline specifically for it.
The gap experiment is conceptually simple. The superconductor is irradiated with photons of known energy, and the energies of the ejected electrons are measured experimentally. The original energy of the electrons is then calculated by subtracting the energy of the ejected electrons from the photon energy. (Olson and Lynch also measure the angular distribution of the ejected electrons, which allows them to determine their original momentum, a parameter of additional interest.)
But the experiment is not easy to do well. The problem is that the photon energy is necessarily a big number, and the superconducting gap is very, very small. The electrons near the gap are most efficiently ejected by photons with an energy of 20 electron volts, and the bandgap is roughly 20 thousandths of an electron volt. "It's like subtracting 10,739 from 10,742 to get 3," says Lynch. "You can get 3 that way, but it's a hard way to get 3. You have to determine your big number very accurately in order to derive your small number accurately."
Olson and Lynch first performed this experiment in 1989 with a beamline designed for general-purpose photoelectron spectroscopy. "We were able to say the superconducting gap is 20 millielectron volts plus or minus five millielectron volts, which isn't terribly accurate," Lynch says, "although it was better than anything that previously existed. Photoemission gave the first measurement of the gap that was reliable, reproducible and believable."
The goal in designing the new beamline was to get four times the energy and angle resolution of the earlier experiment without taking longer to collect data. And it turns out that to achieve this goal, 64 times more light must come down the pipe to the sample.
The electrons in the storage ring radiate light when they are deflected by the bending magnets that keep them on a circular path. But the light they radiate is spread out over many wavelengths, so most of it must be thrown away to do photoelectron spectroscopy, which requires a known wavelength.
To coax more light out of the electrons, the physicists will use an undulator, a row of magnets of alternating polarity that nudge the electrons first in one direction and then in the opposite direction, so that they wobble ever so slightly. The rapid wobbles make the electrons radiate much more light than the slow curve through the bending magnets - roughly as many times more light as there are magnets in the row.
Moreover, because an electron is traveling at nearly the same speed as the light it radiates, the light radiated at the top of one wobble interferes with the light radiated at the top of the next wobble, much as would the ripples made by two stones thrown into a pond simultaneously. Because of this interference, the light emerging from the undulator is concentrated at a few wavelengths instead of spread over many. By tuning into one of these wavelengths, physicists get about five times more light to play with.
"But there's another gain, a much bigger gain," says Lynch. "This is Cliff's idea, and it's the really clever aspect of the design." It has to do with mirrors and the undesirability of mirrors, Lynch explains. A bending magnet produces a fan of radiation that must be focused by a mirror on the monochromator that selects one wavelength for the experiment. The radiation must then be refocused on the sample by another mirror. In total, there may be as many as four mirrors in the beamline.
"These mirrors are terrible," Lynch says. "Mirrors for the visible spectrum will reflect 98 percent of the light striking them. Mirrors for these short wavelengths - if you were to look at them the way you look in the bathroom mirror - reflect well under 1 percent. By using them at grazing angles, you can bring the reflectance back up to 80 percent or so, but the image quality is very poor, so little light gets through.
"Now, the angular divergence of the radiation from an undulator is very small," Lynch continues. "The radiation comes out in a cone, and the half angle of the cone is less than a tenth of a degree both horizontally and vertically. That means you can get away with no mirrors. The only optical element in the beamline is the monochromator, and you have to have that. Between the undulator and the monochromator the beam travels about 14 meters, and between the monochromator and the exit slit it travels another 2.5 meters. Yet at the sample we've still got a very small spot." The monochromator helps too, because it has a spherical surface and therefore focuses the light as well as diffracting it according to wavelength.
"So we gain a factor of five by sitting on a peak wavelength," Lynch summarizes, "and we gain another larger factor by getting rid of the mirrors. Remember, we need 64 times more light getting through. Whether we'll get 53 times or 72 times, we don't know. The big uncertainty is these mirror reflectances, which depend on wavelength. But we think 64 can be done. "
The public hooplah over the new superconductors died down long ago, but this doesn't mean scientists are no longer talking about them. "There are over 38,000 papers on high-temperature superconductors in the High-Tc Superconductivity Information Center at Ames Lab," says Lynch. "We do not know how to interpret the experimental values we have obtained, and nobody else does either.
"At a conference last summer, people came up with some very bizarre explanations for superconductivity, but many could not be used to predict experimental results," he continues. "They were just strange ideas that remained strange ideas. Right now, the guy who is able to explain the most is David Pines of the University of Illinois at Urbana-Champaign. Pines says he can explain 30 different pieces of experimental information, but there are another eight or ten he thinks are probably correct that he cannot explain. At least that's what he said last summer."
By next summer, Pines and his fellow theoreticians will have several more experimental rocks to weight their theoretical balloons, courtesy of Olson and Lynch, and the beamline with the world's best angle and energy resolution for photoemission studies.
For more information:
Clifford Olson
Synchrotron Radiation Center
Stoughton, WI
Phone: 608-877-2224
Last summer three Iowa high school teachers thought they were coming to the Ames Laboratory to gain experience working in a research environment. Imagine their surprise when they found themselves out on the street.
While taking part in the Lab's Teacher Research Associates (TRAC) program (see Inquiry, Winter 1992), the teachers, Deanna Snyder, Randy Daniels and Neil Lundgren, took a ride on the information superhighway, or Internet. As luck would have it, they met James Vary and Doug Fils, who were cruising the same expressway.
"Just like a highway, the Internet is basically a structure," says Vary. "But then there's the traffic on the highway. That's the information - the exchange," he explains.
Helping the TRAC teachers benefit from that exchange, Vary, acting director for the International Institute of Theoretical and Applied Physics (IITAP) at Iowa State University (ISU), invited them to ride with him and Fils and discover ways they could use the Internet for teaching math and science.
"IITAP was established by ISU and the United Nations Educational, Scientific and Cultural Organization in response to the need for greater international exchange in science and technology," says Vary. "We see education as an integral part of our science mission, especially testing out concepts about how to communicate in mathematics and the physical sciences using computer networks."
Chris Ohana, Ames Lab assistant education coordinator, adds, "Educating teachers about novel ways they can use computer networks to convey math and science concepts supports a TRAC program goal to give teachers research experiences they can take back to the classroom to enhance their math and science curricula."
"This outreach project with the TRAC teachers was an opportunity for us at IITAP to learn as well as to develop ideas that will benefit Iowa and regions all over the world," says Vary. "At IITAP we hope to build a strong networked community of educators at the frontier of math and science education."
Becoming part of that education vanguard, the TRAC teachers started exploring computer networks working under an IITAP project called Network Uses for Math and Physical Sciences (NUMAPS). Fils, NUMAPS coordinator, helped the teachers investigate some of the Internet's many tools, such as electronic mail and the World Wide Web information server.
Coming to the NUMAPS program with a good understanding of the Internet's capabilities, Snyder and Daniels soon took on a new but familiar job - teaching. Focusing their talents on another IITAP program called Counterparts, they helped teachers from developing countries learn how they can make the Internet work for them when they return to their own classrooms.
"To truly take advantage of the Internet, you should exploit its uniqueness," says Fils. "What's unique about a computer network is the ability to interact through the system, either with people, with other computers or with information. So the TRAC teachers focused on the interactive capabilities of the Internet. They worked on educational models for topics such as trigonometry and the physics of sound that could be run on the `net.' "
Snyder wrote an interactive, on-line program to teach Fourier analysis to students in some of her physics classes at Ankeny High School in Ankeny, IA. "Through the Internet, the program can be made available to other teachers in Iowa or around the world," she says. "The communication possibilities are one of the most impressive features of the Internet."
Along with the Internet's communication potential comes the ability to establish connections and draw on resources that might not otherwise be available. This was a valuable aspect of using computer networks that Daniels says he discovered through his NUMAPS experience. Even though he's working in his classroom at Ankeny High School, he can use the Internet to continue exchanging ideas with IITAP employees and other teachers.
Lundgren, who teaches at Gladbrook-Reinbeck High School in Reinbeck, IA, says participating in the NUMAPS project through the Lab's TRAC program helped him feel more at ease using the Internet. "Summer opportunities like this allow teachers the time needed to completely familiarize themselves with new computer software and technology - time that is not always available during the school year."
After 20 years as an educator, Lundgren says he has not seen any changes in teaching as dramatic as those being initiated by teaching with computers. "The use of computer networks could really change everything," he says. "Students could become involved in developing creative computer learning modules to teach specific topics to their fellow students. Those students who use the modules on the network may think of ways to improve them. That could really open doors to learning."
Helping to keep those doors wide open, Vary and Fils plan to continue IITAP's partnership with Ames Lab, involving new TRAC teachers in the NUMAPS project and bringing former participants back to teach as well as to pursue the development of learning materials.
"We have excellent computer capability at IITAP," says Fils, "but the TRAC teachers push us. They challenge us to do things we might not otherwise have tried, and that enables us to offer better capabilities to our IITAP researchers. In turn, the educators learn what's really being done with the information superhighway. We have a lot to offer each other. The flow both ways is tremendous."
What does it take to revolutionize technology? Just ask the folks at ETREMA Products.
"We have about 350 customers worldwide using Terfenol-D right now," says Larry Larson, chairman and CEO of ETREMA, a company in Ames, IA, founded on technology from Ames Laboratory. "Many of them are trying to figure out how best to use Terfenol-D to improve existing components or manufacturing systems. Some are building completely new products that weren't possible before Terfenol-D."
First discovered in research on high-power sonar at the Naval Ordinance Laboratory (the `nol' in the name), Terfenol-D is a new metal alloy leading a branch of technology called "smart materials." These include materials such as shape memory alloys, electrostrictive materials and magnetostrictive materials, such as Terfenol-D, which change shape when exposed to a magnetic field and produce an electric charge when compressed. According to Larson, Terfenol-D is the most efficient, accurate and powerful material of its kind now on the market.
After conception in the Navy, Terfenol-D came to the Ames Laboratory. "The Laboratory has expertise in rare-earth metals and metallurgy, and this material involved two rare-earth elements," says Dale McMasters, a research metallurgist at Ames Lab in the mid-1970s, now vice president and chief scientist at ETREMA. The two rare earths are terbium and dysprosium, which lend `Ter' and `D' to the name. Iron completes the name with its atomic symbol, Fe.
McMasters and Ames Lab took the Terfenol-D formula the next step. "I was in a metallurgy group where we worked on Terfenol-D development to get it into a form useful for practical applications," he says. McMasters is co-inventor of the patented processes for producing Terfenol-D.
About a decade later, a group of Des Moines business leaders came together to search for commercially viable technologies in Iowa. Through talking with officials from Ames Laboratory and Iowa State University, the group became aware of Terfenol-D's great potential and in 1987 helped to create Edge Technologies and its first subsidiary, Edge Technologies Rare-Earth Magnetostrictive Alloy (ETREMA) Products. ETREMA's sole purpose is to commercialize the new material.
"One of the major objectives of Edge is to start new Iowa-based businesses that will develop and commercialize technologies resulting from local research, providing industrial diversification, creating new jobs and contributing to the state's economic security," says Ames Laboratory Division Director for Planning and Technology Application Dan Williams, who was instrumental in establishing the new company.
Now in the hands of ETREMA, Terfenol-D has made its industrial debut. "Industry is really catching on to the possibilities it has," says Jody Zahn, public relations coordinator for ETREMA. "A few years ago, hardly anybody knew anything about Terfenol-D, ETREMA or even Ames." She says it's now a challenge just to keep up with the demand.
"We're hoping to do a lot of great things with it," says Ray Porzio, the manager of Sub- marine Surveillance Systems at the Lockheed Sanders Corp. in Nashua, NH. Porzio is incorporating Terfenol-D into advanced sonar systems. "Our approach is to take existing technology and replace it with a Terfenol-D transducer that is one-third the size and weight yet has the same power level and bandwidth," he says. "As time goes on and we understand the material better, it will become easier and easier to design with Terfenol-D."
Such promising developments are prompting ETREMA to expand its present facility to handle large-scale production. The new plant could add 1,200 to 1,800 new jobs, about half of which will be in high-tech fields. "Another goal of Edge was to provide a place for science and engineering graduates of Iowa schools to be employed in Iowa rather than be forced to leave the state," says Williams.
Many in those high-tech positions will be busy developing Terfenol-D applications, likely to number well in the hundreds. Here are just a few more examples that demonstrate Terfenol-D's adaptability:
Ames Laboratory scientists help build"clean cars"
Ames Laboratory has joined an ambitious government-industry partnership working to develop vehicles that can travel 128 kilometers (80 miles) on a gallon of gas.
The Partnership for a New Generation of Vehicles (PNGV) includes members from eight federal agencies, including the Department of Energy (DOE), and the Big Three automakers, Chrysler, Ford and General Motors. The partnership's ultimate goal is to develop a "clean car" prototype by the year 2004 that will deliver up to three times the fuel efficiency of today's vehicles, without increasing price or operating costs and while meeting appropriate quality, performance, safety and emissions requirements. Additional goals include significantly improving U.S. competitiveness in automotive manufacturing and applying innovations to conventional vehicles.
A subgroup of PNGV, the Clean Car Coordinating Committee (C4), includes members from a select group of DOE national laboratories. Ames Laboratory Senior Metallurgist Iver Anderson has been representing Ames Lab on that committee since August 1994. "Ames Lab was picked to be a member of the committee because of the quantity and quality of materials research we're currently performing in collaboration with the automotive industry," says Anderson. "Much of that work has the potential to be included under the PNGV technology umbrella."
Scientists agree that increasing vehicle fuel efficiency requires a dramatic decrease in vehicle weight. Anderson puts the needed weight reduction at 40 percent, or approximately 545 kilograms (1,200 pounds). He says much of the reduction can be achieved in the body and chassis of the automobile through the use of lightweight materials, such as aluminum and magnesium, but he adds that weight reductions in engine and drivetrain parts are also being investigated.
"The development of lightweight materials is an area where Ames Lab can really be in `the driver's seat' in the PNGV initiative," says Anderson. "We're heavily involved in lightweight materials research, and we're expanding our efforts. Our group has developed a process for producing low-cost, lightweight aluminum powders that can be formed into drivetrain components, such as connecting rods in engines. Our materials can cut the weight of an automobile's structural parts by one-half to one-third." Anderson adds that the DOE is in the last stages of negotiating a cooperative research and development agreement with the U. S. Automotive Materials Partnership, the industry consortium conducting R&D in lightweight and other advanced materials for the PNGV initiative. The agreement will allow him to conduct further materials research.
And Anderson's powder process is just one of many technologies Ames Laboratory scientists are contributing to the PNGV initiative. Another, a monitor called Ultraform with potential for on-line application, can help automakers manufacture lightweight aluminum body parts. Bruce Thompson, Ames Lab division director for Science and Technology, says Ultraform uses ultrasonic waves to measure a metal's texture to determine its drawability. Drawing is the process used to deform sheet metal into thin, complex shapes. Thompson says, "Ultraform predicts a material's formability, which will play an increasingly important role as we design and use materials closer and closer to their limits."
PNGV has set an ambitious schedule for developing this new line of fuel-efficient, lightweight vehicles. In 1997 the group will select the final technology mix that will be used for the concept vehicles and production prototypes. Anderson says it's very important for Ames Lab to play a part in developing that technology mix. "We want to hang as many parts on the `supercar' as we can because transportation technology, particularly the automobile, has been iden-tified as a key sector of the economy that will receive Congressional funding for research."
Ford, Chrysler and General Motors anticipate developing a concept vehicle by the year 2000 and a production prototype by 2004.
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