News about Science, Technology and Engineering at Iowa State University
New Technology Reduces Noise
To reduce irritating sounds emitted from office equipment, kitchen appliances and manufacturing machinery, Iowa State Aerospace Engineering and Engineering Mechanics Professor Ken McConnell developed Robust Vibration Suppression (RVS) technology. The innovative technology reduces the clatter normally associated with machines that use stepper motors.
McConnell and Chad Bouton, a former graduate student, first applied RVS technology to stepper motors in ink jet printers. After several years of study that yielded positive results, they went one step further -- testing the technology on a flexible robot arm called FLEXER (Flexible Lightweight Experimental Evaluation Robot).
They replaced FLEXER's standard DC motor with a stepper motor. The goal was to move the flexible robot arm from one position to another as quickly as possible without residual vibration. The RVS method involves taking full advantage of the dynamic characteristics of a given machine. Once these characteristics are known, it is a relatively simple matter to make the machine perform at its dynamic limits. Again, McConnell and Bouton were successful, publishing their research findings in Sound and Vibration magazine.
"The RVS control method has a tremendous range of practical applications," said McConnell. "Industrial manufacturers are interested in robots that move faster, cut down on noise and use less energy. But the RVS method is also ideal for any product that requires precision positioning." For more information call Ken McConnell at (515) 294-2884 or Mitch Mihalovich, Engineering Communications, (515) 294-4344.
Virtual artistry
Iowa State University virtual reality expert Carolina Cruz-Neira continues to find new avenues to express herself. The latest is a series of images that are now part of a museum exhibit. Cruz-Neira, a Litton Assistant Professor of Electrical and Computer Engineering, and her students have made several images for the Museum of Jewish Heritage in New York City in the exhibit "A Living Memorial to the Holocaust."
Sixteen three-dimensional images in the Museum Rotunda Gallery were created by the Iowa State team by combining high-tech computer graphics with aging artifacts. The result is a "virtual collage with historical references and documentation," the museum states.
The full-color, 30- by 40-inch images look like transparencies but appear as three dimensional from any angle. The Iowa State team began its work by examining photographs of the 16 objects -- a baby's shoe, a sewing machine and a lamp, for example -- from various angles. Cruz-Neira then used the photos to create computer images, which she said provided the right colors, textures and shadings making them look life-like and not as computer images. They then scanned photos and video images into their computers to provide contextual settings for the images -- like putting the baby's shoe on a coffee table with photos in the background.
"This was a very challenging project because we weren't just putting up computer models and making them into photographs," Cruz-Neira said. "We were representing historical events." The images can be seen by accessing the museum's web page at http://www.artn.nwu.edu/MJHRotundaPHSColograms/index.html. For more information call Cruz-Neira at (515) 294-4192, or Skip Derra, News Service, (515) 294-4917.
The Big Chill
Scientists at the Department of Energy's Ames Laboratory at Iowa State University have discovered a new class of materials that boost the cooling power of materials used for magnetic refrigeration. The new materials are made of a gadolinium-silicon-germanium (Gd5Si2Ge2) alloy. The compound exhibits a magnetocaloric effect -- the ability to heat up when its magnetized and to cool back down when its demagnetized. The new compound has about twice the magnetocaloric effect of gadolinium, the best known magnetic refrigerant material for near-room-temperature applications.
The efficiency of the gadolinium-silicon-germanium materials make magnetic refrigeration even more competitive with conventional gas-compression technology, opening the door for potential small-scale applications such as climate control in cars and homes, and in home refrigerators and freezers, said Karl Gschneidner, a distinguished professor of materials science and engineering and a scientist at the Ames Laboratory. For more information, call Gschneidner at (515) 294-7931 or Steve Karsjen, Ames Laboratory Public Affairs, (515) 294-5643.
Thin and smart
Researchers at Iowa State University's Microelectronics Research Center have successfully developed working integrated circuits that are thinner than a human hair. By adding crystalline and noncrystalline thin-film silicon-based circuits directly on large-area polyimide plastic bases, MRC has reduced by 100 the thickness of transistor circuits used in standard applications.
Currently, devices of similar dimension (lengths of 2 to 6 micrometers) are 400 micrometers thick. The ultrathin-film transistors developed at MRC are less than 5 micrometers thick, including the substrate. Multiple layer circuits are created when successive layers of polyimide with devices are added, making complex two- and three-dimensional integrated circuits possible. With the use of new tools such as focused ion beam technology, the devices can eventually be reduced to the nanometer range.
The patented technology will permit roll-to-roll processing, a less expensive manufacturing method that allows mass production while improving reliability and capability. MRC has successfully spun off a solar cell manufacturing company that uses the roll-to-roll process.
Ultrathin electronics is the basis for new classes of commercial, industrial and military products, including smart cards, displays, imaging devices and a variety of novel circuit applications. Thin-film electronics has the potential to change the way integrated circuits are designed, and could impact innovations in interconnections, lithography and future generations of integrated circuit technology. For information, call Howard Shanks at (515) 294-7732, or Anita Rollins, IPRT Communications, (515) 294-1113.
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