As the weather turns spring-like, winter's ice build-up on power lines, windshields, and airplane wings becomes a fading memory. Professor Victor Petrenko, of Thayer School of Engineering at Dartmouth College (Dartmouth, NH), hopes to keep it that way. The physicist discovered that applying a small electric voltage across an ice-metal interface can break the bond between ice and metal surfaces. Technically, Petrenko says, ice is a semiconductor--included in a small class of substances in which protons, rather than electrons, carry an electrical current. When an electrically-charged surface comes into contact with any other surface, the charged surface induces an opposite charge in the facing surface and, because opposites attract, the two surfaces are drawn together. "This simple attraction accounts for most of ice adhesion," says Petrenko. Breaking the bond between ice and metal, he reasoned, should be as simple as neutralizing the surface charge with an equal amount of its opposite. He tested his theory using a sheet of ice, a globule of mercury--which stays liquid until temperatures dip below -40F--and a small battery with two wires attached. He touched one wire to the ice, the other to the mercury. The mercury drew itself up and away from the ice. Petrenko repeated the experiment using steel and other solid metals. In each case, the electricity caused the ice to lose adhesion. The effect could also be reversed, causing a surface to stick more firmly to the ice. "It may be possible to prevent or significantly reduce icing on the wings of an airplane using a battery no bigger than the one in your car," Petrenko theorizes. Surface-to-surface interactions are also important in manufacturing and machinery. Call: (603) 646-2117.
It won't be too much longer and hardware design, as we used to know it, will be remembered alongside the slide rule and the Karnaugh map. You will need to move beyond those familiar bits and bytes into the new world of software centric design.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.