News Service

September 1999

News about Science, Technology and Engineering at Iowa State University

Fuzzy logic aids stroke victims

While proving that fuzzy logic analysis can work in clinical medicine studies, an Iowa State University engineer and a University of Illinois-Chicago neurologist uncovered a new finding that may offer doctors an additional treatment option for stroke patients -- vitamin B12.

Dr. Cathy Helgason, who directs the stroke center at the University of Illinois-Chicago Hospitals, wanted to confirm what she was seeing in her patients -- strokes have multiple, interacting causes that vary by degree. She believed she could document her hypothesis using fuzzy logic, a mathematical approach in which set boundaries (stroke causes) are imprecise as opposed to traditional set theory in which an event either occurs or does not occur. Helgason enlisted Julie Dickerson, an electrical and computer engineering assistant professor and fuzzy logic researcher at Iowa State.

In their study, the vitamin, metabolite and homocysteine (an amino acid) levels were measured in 166 patients with a history of stroke. The researchers looked at the relationship between variables that may lead, when interacting in disease, to stroke and heart attack through the abnormal accumulation of homocysteine. Using fuzzy logic algorithms and fuzzy logic conditioning clustering to analyze the data, they found that low levels of B12 co-occur with high homocysteine levels.

"In patients with underlying atherosclerotic disease due to other causes, mildly elevated homocysteine may be important interactively in accelerating both pathologies," said Helgason. She and Dickerson plan to test the link between B12 and homocysteine in a larger study. For more information, contact Dickerson, (515) 294-7705; Helgason, (312) 996-6497; or Teddi Barron, Engineering Communications, (515) 294-0262.

Hooked on photonics

Since 1990, when they first theoretically demonstrated the existence of the photonic bandgap crystal, Ames Lab physicist and ISU physics and astronomy professor Kai-Ming Ho and his colleagues have steadily been advancing the research. Now, the U.S. Department of Energy's Ames Laboratory research team is on the verge of achieving its goal -- synthesis of three-dimensional optical photonic crystals.

That goal may be reached sooner than expected thanks to the addition of a materials scientist to Ho's research team. Kristen Constant, an Iowa State associate professor of materials science and engineering and an Ames Lab associate, developed a novel ceramic technique for creating colloidal optical photonic crystals using inexpensive and non-toxic materials. The colloidal crystals possess a periodic structure that resembles a honeycomb and have a photonic bandgap -- a range of forbidden frequencies within which a specific electromagnetic wavelength is blocked, and light is reflected.

Three-dimensional photonic crystals that operate at optical wavelengths are capturing the imagination of researchers because of their potential applications in light control and manipulation including light-emitting diodes, micro-fabricated lasers, waveguides and optical switches for telecommunications. Contact Ho, (515) 294-1960; Constant, (515) 294-3337; or Saren Johnston, Ames Lab Public Affairs, (515) 294-3474.

Complex designed to spark learning

A new active learning complex in Iowa State's department of electrical and computer engineering doesn't look anything like a classroom and that's what makes it effective. Bright lights in a sterile room with straight back chairs and flip-up desktops are replaced with a comfortable environment in a room flush with vibrant colors.

The goal of the active learning complex is to enhance learning by fostering communications and teamwork, said Doug Jacobson, faculty coordinator of the complex and associate professor of electrical and computer engineering. "We wanted it to be comfortable, because comfort facilitates discussion which facilitates learning," he said.

The complex includes several interaction areas where students can work on problems, and office space for 28 teaching assistants. There are four high-tech interaction areas -- cozy enclaves that utilize several pieces of technology to aid learning. These interaction areas include white boards, where students can draw diagrams and work out problems and then save their work to computer. There are "wireless" infrared keyboards, which facilitate students working together in groups by sharing the keyboard and large-screen computer. Bright awnings cover the office and interaction areas.

"The complex is designed to foster interaction and use of technology, to encourage the discussion of ideas and have ready access to teaching assistants," added Jacobson. "It brings everything and everyone together and helps build friendships and bonds that will be valuable in the learning process." For more information contact, Jacobson, (515) 294-8307, or Skip Derra, News Service, (515) 294-4917.

Aircraft safety testing moves from an art to an innovative technology

Scientists at Iowa State University's Center for Nondestructive Evaluation and the Airworthiness Assurance Center of Excellence are bringing aircraft safety testing to a new level with the instrumented tapper. Designed by David Hsu and a team of researchers at CNDE, the tapper replaces the traditional method of tapping a coin on honeycomb and composite aircraft parts to inspect for damage.

The instrumented tapper is inexpensive, requires little training to operate and provides a reliable method of inspection that isn't hindered by aircraft hangar noise. Attached to a notebook computer, the tapper's accelerometer translates the stiffness of a part's surface into digital information in a Microsoft Excel file. Circuits measure impact duration, the length of contact the accelerometer tip has on intact or damaged parts, and an image of the results is displayed on a computer monitor.

The tapper has been tested at Northwest Airlines, Minneapolis, Minn.; American Airlines, Tulsa, Okla.; TWA, Kansas City, Mo.; and the Iowa Army National Guard and Iowa Air National Guard. For more information, contact Hsu, (515) 294-2501, or Danelle Baker-Miller, IPRT Public Affairs, (515) 294-5635.

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