12-98
Contact:
Skip Derra, News Service, (515) 294-4917
NEWS ABOUT SCIENCE, TECHNOLOGY AND ENGINEERING
AT IOWA STATE UNIVERSITY
AMES, Iowa--
New glue solves sticky ceramics problem
Silicon-carbide composites may someday replace steel and superalloys because they can withstand higher temperatures while resisting corrosion. But first, manufacturers need a practical method of joining these materials in an ambient air environment because traditional ceramic joining processes are ineffective with the composites.
Ames Laboratory scientists have developed and tested a glue to meet those needs. It is made of silicon-bearing polymers and an aluminum-silicon alloy powder, and produces joints with strengths of up to 14,500 psi at 1200 C (2200 F). That's a vast improvement over steel, which has little strength at temperatures above 700 C. The easy-to-use glue can be heated with a propane torch and cured in air -- a marked improvement over the elaborate, high-temperature curing furnaces used in traditional ceramic-joining methods.
"This is probably the only glue that can join ceramic composites in an air atmosphere and produce the needed strength," said Sina Maghsoodi, an Ames Lab chemist who helped invent the glue. Contact Maghsoodi at (515) 294-1110, or Susan Dieterle, Ames Lab Public Affairs, (515) 294- 1405.
Adding a charge to separations
A novel technique may transform the way chromatography, a chemical separation method, is conducted. A research team led by Marc Porter of the Institute for Physical Research and Technology at Iowa State University is replacing the traditional chromatography column, in which chemical separations are made, with an electrochemical cell.
"What we've found is a way to conduct a number of separations without changing the solid material in the column," Porter said. "This process will potentially save time, reduce costs and create less hazardous waste."
Chromatography can generate large volumes of mixed waste, which poses costly disposal problems, while requiring numerous separations with various column materials in order to identify all of the elements in a mixture. Porter's column uses a conductive stationary phase substance in the place of the porous column material. Manipulation of the separations can then be made electrically by changing the electrical potential applied to the column. This permits a variety of separations using only one mobile phase material. Use of this technology can reduce analysis costs, minimize wastes and reduce the cost of waste disposal. The technology holds promise for a number of analyses, including separation of pharmaceutical chemicals. Contact Porter at (515) 294-6433 or Anita Rollins, IPRT Public Affairs, (515) 294-1113.
Isoflavone advance made by visiting Kenyan chemist
A new method for synthesizing a difficult-to-make isoflavone, a cancer-fighting substance found in some plants, was developed by a Kenyan scientist visiting Iowa State University this past summer. Organic chemist Caroline Lang'at, of Kenyatta University, Nairobi, Kenya, worked with Iowa State food toxicologist Pat Murphy to develop a much simpler method for synthesizing a key chemical compound in making the isoflavone glycitein. Lang'at's work was part of her participation in Iowa State's International Women in Science and Engineering (IWISE) summer workshop. The workshop teaches leadership skills to women scientists from around the world. It is the only program of its type in existence, said Mary Ann Evans, IWISE co-director.
A simple way of making glycitein could be a boon for research into isoflavones, Murphy said. There are three isoflavones in soy -- genistein, daidzein and glycitein -- that act like natural estrogens. Nutritionists believe these compounds reduce the risk of cardiovascular disease, osteoporosis and age-related cancers of the breast, prostate and colon, but they don't entirely understand how or why. Researchers know a lot about genistein and daidzein because they are easy to obtain. But glycitein has had relatively little lab work done on it due to its scarcity. "What Caroline did was come up with a way to make a key intermediate (an essential chemical to obtain glycitein) in a process of 'organic chemistry for dummies,'" Murphy said. "It's a one-bowl process. That's the beauty of it."
Murphy's research group has submitted a paper to the Journal of Ag and Food Chemistry in the hopes of making Lang'at's process known to a wide range of researchers. She thinks that with an abundance of glycitein, researchers will get the whole picture of what makes isoflavones so beneficial when consumed by humans.
Lang'at visited Iowa State as part of the eight-week IWISE program. IWISE co-director Evans said the program has positive effects on its participants. "Some of our participants, like Caroline Lang'at, have really opened doors for themselves."
When Lang'at returned to Kenya she was named chair of the chemistry department at Kenyatta University. "Having completed the IWISE program has made it easier for me to face my new challenge," Lang'at said. Contact Murphy, Food Science and Human Nutrition, (515) 294-1970; Mary Ann Evans, IWISE, (515) 294-5883; or Skip Derra, News Service, (515) 294- 4917.
Engineering professors awarded 22 patents
The College of Engineering recently honored 24 faculty members who received patents this past year. "This was a precedent-setting year," said Ted Okiishi, associate engineering dean. This year's 22 patents, compared to eight last year, include an odor controlling method for waste water lagoons, ozone-friendly refrigerants, environmentally friendly hydropowered turbine systems, surgical laser fibers and methods to evaluate vibrations of golf clubs.
For a complete list of patents received, contact Okiishi at (515) 294-4395, or Mitch Mihalovich, Engineering Communications, (515) 294-4344.
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