November 1999

News about Science, Technology and Engineering at Iowa State University

Cutting the clatter in space
Space may be cold, black, and empty, but it sure isn't quiet. At least not when humans are involved. "It's immensely loud up there," says J. Adin Mann III, an ISU aerospace engineering and engineering mechanics associate professor. "Astronauts come back from the space shuttle with temporary hearing loss, even after a 7- to 10-day mission."

That has serious implications for longer stays, especially on the international space station that's being built. Mann devoted a portion of his recent faculty leave to helping NASA put a damper on all the space racket. After spending eight months at Royal Appliance, Cleveland, working on the Dirt Devil vacuum, Mann spent four months splitting time between Royal and the NASA Glenn Research Center, also in Cleveland.

"The noise level can get to up to 75 decibels in the space station module that's up there now, and it's being used as the living area," Mann said. Noise from computer disk drives, cooling fans, and agitators used in experiments are just part of the problem. Astronauts will literally be surrounded by noisy equipment, which is being built into drawer-like containers that slide into racks in the walls. "There are even some combustion experiments that use small explosions," Mann said. "The weight requirements are so severe that few noise reduction materials are being used."

Mann worked with teams designing the packaging for experiments, and helped with the mechanical and electronic designs. "Often it's just that the cooling fan noise is loud, and that can be handled by putting sound absorption into the racks," he said. Other solutions include the use of resilient rather than rigid mounts or adjusting the construction of the racks. For more information contact Mann, (515) 294-2877, or Eric Dieterle, Engineering Communications, (515) 294-0260.

Polymer nanotechnology
An Iowa State University professor is developing technologies for making incredibly small polymers. Polymer nanotechnology, says Joshua Otaigbe, an ISU assistant professor of materials science engineering and chemical engineering, is the science of developing tools and machines that are no larger than a single molecule. "The implications of highly specialized machines smaller than a piece of dust is astounding," Otaigbe said. "They will have as big an impact on our lives as transistors did 40 years ago."

Otaigbe has been working on a method for using micro-droplets of an evaporating polymer solution. The research grew out of a collaboration between Otaigbe and scientists at Oak Ridge (Tenn.) National Laboratory. "For small droplets of a solution, solvent evaporation takes place quickly enough to suppress phase separation, producing dry polymer-blend particles that have a uniform structure to within molecular dimensions, making them smaller than dust particles," he said. Otaigbe recently received a $257,000, three year grant from the National Science Foundation to continue work on polymer nanotechnologies. These materials could have a variety of uses, but researchers believe one of the first could be as specially engineered molecules that would be introduced into cells within the body as part of medical treatments.

"We will use the NSF funding to expand the research to generating, characterizing and modeling the interesting structures and properties of polymer nanoparticles," Otaigbe said. For more information, contact Otaigbe, (515) 294-9678, or Skip Derra, News Service, (515) 294-4917.

A gem of a discovery
Researchers at the U.S. Department of Energy's Ames Laboratory have found a material they believe will join the ranks of diamond and cubic boron-nitride as ultrahard materials used in grinding and machining applications. Ames Lab associate scientist Bruce Cook discovered that introducing a small amount of silicon and other additives into an alloy of aluminum-magnesium-boron creates the second-hardest bulk substance after diamond. In the initial round of tests on several different instruments, the material's hardness was measured at 46 gigapascals (the equivalent of 6.7 million pounds per square inch). That's slightly higher than cubic boron-nitride's hardness of 45 GPa (6.5 million psi) and below diamond's hardness of between 70 and 100 GPa (10.2-14.5 million psi).

Cook said that if the material lives up to its promise, it could mean big cost savings for manufacturers who use these types of materials in abrasives and cutting tools -- especially for the auto industry, which relies heavily on cubic boron-nitride for grinding and machining hardened steel. Cubic boron-nitride costs about $7,000 per pound, while the aluminum-magnesium-boron compound is estimated to cost about $700 per pound. Diamond costs around $2,000 per pound but can't be used with steel because it turns into graphite when brought into contact with iron-based materials at high temperatures.

Cook and his colleagues are looking for additional funding to further explore the material's preparation and properties. For more information, contact Cook, (515) 294-9673, or Susan Dieterle, Ames Lab Public Affairs, (515) 294-1405.

ISU acquires "new" supercomputer
The Center for Physical and Computational Mathematics (CPCM) and the Ames Laboratory have acquired a 256-node Intel Paragon supercomputer. The fastest computer in Iowa and among the top 300 fastest supercomputers in the world, the Paragon can perform complex simulations that are too large and time-consuming for standard PCs and workstations.

Housed in ISU's Durham Center, the Paragon is currently one-quarter of its size when stationed at its former home, Oak Ridge (Tenn.) National Laboratory. Following the Paragon's decommission at Oak Ridge, ISU scientists and Pete Siegel, ISU's director of academic information technology, obtained it for the costs of shipping and installation. Ames Laboratory and CPCM researchers are currently using the Paragon to determine the melting point of materials whose melting temperatures are so high they cannot be duplicated in a laboratory setting.

The supercomputer is also used to simulate the movement of electronic waves through various media. These simulations are leading to new designs using photonic band gap materials, crystals that allow researchers to direct visible light around assigned paths. Future plans for the Paragon include parallel processing applications and use in multiprocessor architecture classes at ISU. For more information contact Bruce Harmon, CPCM, (515) 294-1490; Dave Turner, CPCM, (515) 294-8872; or Danelle Baker-Miller, IPRT Public Affairs, (515) 294-5635.

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