Developments to Watch
GIVE MRIs A LITTLE STATIC, AND THEY MIGHT BE CHEAPER
Static electricity isn't popular. If it's not blowing circuits, it's causing clothes to cling. But Lawrence M. Silverberg, an associate professor of mechanical engineering at North Carolina State University, says static electricity has a good side, too. For example, it could reduce the cost of the magnetic resonance imaging (MRI) systems used in hospitals and clinics.
MRI systems use an array of dish-type antennae to pinpoint the location of signals reflected from within a patient's body. "Fancy and expensive," these antennae could be replaced by one cheap electrostatic antenna that can change shape, says Silverberg. He pins the center of a thin conductive-polymer film to a metal plate. Given a static charge, the film stiffens. Then, juice fed to the metal plate produces a repulsive force that bends the film outward from its center, creating a dish antenna. By meticulously regulating the electrostatic energy, Silverberg can shape the dish so it plots the distances and directions of reflected MRI signals. The same technique could be used to make satellite antennae that could scan the earth by changing shape, eliminating the need to reposition the entire satellite. Several companies are negotiating for licenses to the patented technology, Silverberg adds.EDITED BY RUTH COXETER