June 2000

News about Science, Technology and Engineering at Iowa State University

Piecing together the quasicrystal puzzle
Research at the U.S. Department of Energy's Ames Laboratory at Iowa State University has helped solve one of the key questions surrounding the surface properties of quasicrystals, relatively new materials that scientists believe are well-suited for use as coatings on automotive and mechanical parts. The materials are extremely hard, have low coefficients of friction and are highly resistant to corrosion and wear-related damage.

The 1982 discovery of quasicrystal materials, typically aluminum-rich alloys with specific compositions, changed the long-held belief that solid matter existed in only amorphous or crystalline states. Amorphous substances are made up of atoms that exist in a random, disordered manner; while the atoms of crystalline substances form specific geometric patterns that are repeated periodically in the material. Quasicrystals fall outside these groups, containing atoms that are arranged in an ordered but not periodic way.

However, scientists had debated for several years whether the surface had the same ordered, non-repeating structure as the bulk material. A microscopy technique used by Ames Lab scientists indicated that the surface and bulk structures were the same. "This was only one of the pieces of evidence that helped bring about consensus in the quasicrystal community, but it was an important piece," says Pat Thiel, director of the Lab's Materials Chemistry Program.

Thiel, who has been studying quasicrystals for the past five years, says understanding the surface properties will give researchers better insights into the materials themselves, and could increase the possible uses of quasicrystals. For more information, contact Thiel, (515) 294-6342, or Susan Dieterle, Ames Lab Public Affairs, (515) 294-1405.

Power markets
If the lights flicker this summer, or if power is lost completely, the reason may not be as simple as too many air conditioners running at once. Someone may have been gambling with your power, and lost. That's simply part of the new world of deregulated utilities. Researchers in electrical and computer engineering at Iowa State University are busy peering into that world, trying to determine how and why market conditions may contribute to power failures as electricity becomes a commodity.

"There is a shortage of electricity in the United States," says Gerald Sheblé, an ISU electrical engineering professor. While construction of homes and businesses is way up since 1992, when deregulation began, hardly anyone is building power generation facilities because the market is so uncertain, Sheblé explained.

Traditionally, utilities operated as monopolies that generated, transported, and sold power. Deregulation opens the way for those functions to be divided, creating a market of buyers, sellers, and brokers negotiating a tricky, unforgiving system driven by peak demand and riddled with unpredictability.

"The idea of deregulation and competition is to have one price across the country," he said. "But some of those involved don't want the system to work well because they can make money off the present one." The emerging electric power market is a specialty of Sheblé, who recently published a book on the subject. One of his graduate students, Valentin Petrov, is working with computer models to investigate the potential for economic warfare, then to design models that simulate it.

The National Science Foundation funds the market modeling efforts in a $309,000 project jointly conducted with Leigh Tesfatsion of the ISU department of economics. Additional funding comes from the Electric Power Research Institute and the U.S. Department of Defense, who are sponsoring a $1.5 million, five-year project to investigate power network security issues. That project involves three other universities, the University of Washington, Virginia Tech and Arizona State. For more information, contact Sheblé, (515) 294-3046, or Eric Dieterle, Engineering Communications, (515) 294-0260.

ISU center receives gift to improve railroad inspection
Iowa State's Center for Nondestructive Evaluation has received a $66,000 gift from the Krautkramer Branson Company, a German producer of phased-array ultrasound equipment. The gift, which includes a computer and ultrasonic probe, will enable Dave Utrata, a CNDE associate scientist, to expand techniques for detecting and characterizing flaws in steel railroad rails.

The railroad industry currently inspects rail with ultrasonic techniques, and while the techniques do a good job, they may not catch all flaws. Rail inspections are conducted with a fluid-filled wheel suspended under a high-railer inspection vehicle. Fixed transducers inside the wheel pulse ultrasonic waves, which are directed at areas where cracks are most likely to be found. The new phased-array system would allow the inspector to steer the ultrasonic probe, creating beams of ultrasound that would sweep through the rail. "The phased-array system could provide us with a new perspective on flaws in a more sensitive and efficient manner," Utrata said.

After Utrata completes three months of research comparing the phased-array system to the fluid-filled wheel method, the equipment will be given to CNDE to provide research and testing support to Iowa companies. For more information, contact Utrata, (515) 294-6095, or Danelle Baker-Miller, IPRT Public Affairs,
(515) 294-5635.

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