5-1-98

Contacts:
Skip Derra, News Service, (515) 294-4917

NEWS ABOUT SCIENCE, TECHNOLOGY AND ENGINEERING AT IOWA STATE UNIVERSITY

AMES, Iowa --

Making meat safe from contamination

A new way to detect fecal contamination on fresh meat could help industry meet safety regulations designed to control disease-causing bacteria. Using laser-induced fluorescent spectroscopy, Iowa State University Associate Professor of Chemistry Jacob Petrich and Agricultural Research Service microbiologists Mark Rasmussen and Tom Casey, have built a detector that illuminates fecal contamination on meat. Petrich says the device is adaptable to any size packing plant. As a hand-held unit, similar to metal detectors used in airports, the instrument could alert meat packers to fecal contamination in seconds. The contaminated meat fluoresces, or "glows," in a specific color for easy determination of contamination. The contaminated carcass then could be sanitized before the contamination spreads.

Feces are a major source of bacterial contamination in livestock and poultry slaughterhouses, according to Rasmussen. After a 1993 E. coli outbreak in the Pacific Northwest, the USDA developed new sanitation requirements for slaughterhouses, including stiffer inspections for fecal contamination and tests for E. coli. According to Casey, these have not been easy tasks to accomplish with present visual inspection methods.

With the new technology, the inspection job will be easier, faster and more accurate. The ISU/ARS research is timely because the USDA's Food Safety and Inspection Service is enforcing zero-tolerance standard for fecal contamination on livestock and poultry carcasses. The researchers are patenting their technology and discussions are under way with industry on commercial development. Contact Petrich at (515) 294-9422, or Skip Derra, News Service, (515) 294-4917.

Twinkle, twinkle diamond star

A team of about 50 astronomers are training their telescopes on a relatively close pulsating white dwarf star with the goal of possibly finding a true gem in the sky. The astronomers, led by Steve Kawaler, an Iowa State University professor of physics and astronomy, will be monitoring a vibrating white dwarf star designated BPM37093, which is 17 light years from Earth. (A light year is the distance light travels in a year, about 6 trillion miles.)

The astronomers are making their observations using the Whole Earth Telescope and the Hubble Space Telescope from April 17 to May 4. Their findings could have an impact on the age of our galaxy and the universe, and become the delight of gemologists worldwide.

"We think BPM37093 is primarily made up of carbon and oxygen in a crystallized state," Kawaler says. "That would make it a diamond with a blue-green tint. It's estimated carat weight is 1034, or 10 billion trillion trillion. This truly could be a diamond in the sky."

BPM37093 is a slowly cooling remnant of a star that once was a little more massive than our Sun. It resides in the constellation of Centaurus and is clearly viewable only from the Southern Hemisphere. Understanding the properties of white dwarf stars is important because nearly all stars will become eternally cooling white dwarf stars. Only the most massive stars will become fiery exploding supernovas. By measuring the vibration frequency of BPM37093, astronomers can sneak a peak into its interior. Through stellar seismological techniques, Kawaler and the team of astronomers will attempt to ascertain the makeup of BPM37093.

"The pulsations will tell us what's going on inside a star the same way earthquakes tell us about the inside of Earth," Kawaler said. Contact Kawaler at (515) 294-9728, or Skip Derra, News Service, (515) 294-4917.

Conference updates virtual reality

Fire up the rear-projection screens and strap on the data gloves, virtual reality techies from all over the world will be coming to Ames May 11 and 12 to discuss alternate realities during the Second International Immersive Projection Technology Workshop (IPT98). The conference will be held in the Scheman Building and while the topics will be technical in nature, they also are expected to be visual.

"Virtual reality is very visual so you can expect a lot of presenters to include videos of their work," says Carolina Cruz-Neira, Litton assistant professor of electrical and computer engineering and conference chair. The program will cover a range of topics, including screen configurations, projection algorithms, software architectures, applications and networking. IPT98 is a forum to present current research and development activities using projection technology for virtual reality. VR researchers from Germany, Japan, and major practitioners in the U.S. will be making presentations on topics ranging from large-scale immersive displays in entertainment and education to the limits of human vision.

The conference is being hosted by Iowa State's Iowa Center for Emerging Manufacturing Technology and the Fraunhofer Institute For Industrial Engineering, Stuttgart, Germany. Other sponsors include Silicon Graphics Inc., Mountain View, Calif., and Engineering Animation Inc., Ames, Iowa. For more information on the conference call the ICEMT office at (515) 294-3092, or check the web site at http://www.icemt.iastate.edu/ipt98. Contact Cruz-Neira at (515) 294-4192, or Skip Derra, News Service, (515) 294-4917.

Casting tools

Use of castings -- monolithic, poured metal parts that replace a number of smaller components -- can improve a product while saving money by reducing inventory tracking and the need for assemblies. For example, an aircraft door frame could use one casting to replace more than 100 parts. But castings occasionally have pores or inclusions that diminish the component's strength. In order to ensure safety, the weight of the material used may be increased to compensate for the pores and inclusions, but this is often an unsatisfactory and expensive solution.

Now, scientists from Iowa State University's Center for Nondestructive Evaluation (CNDE) are taking a different approach. They are developing tools to help industry determine the types of defects that compromise safety, devise the best plan for inspection and gain a better understand of casting.

CNDE's Joe Gray is working with other researchers to develop a model that can be manipulated to determine what types of defects will occur, the type of defect likely in safety- critical areas, the size of defect that will compromise safety and the testing technique required to locate the defect in a given part. The model will also allow industry to determine how new materials will behave without extensive and expensive testing of large numbers of samples. The tools hold potential for a number of industries, including automotive and aircraft manufacturers. Contact Gray at (515) 294-9745, or Anita Rollins, IPRT Information, (515) 294-1113.

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Revised 5/1/98