Because light emitting diodes (LEDs) convert electrical energy into visible light, they are suitable for use in many types of consumer electronic products. Researchers at the University of Illinois believe there is another practical application for LEDs—a new class of sensors that detect the presence of harmful chemicals. Thomas Kuech, a professor of chemical engineering and materials science at the university, foresees making small optical emitters and detectors that are chemically sensitive to ammonia in factories; biochemical agents used in military or terrorists situations; and radon, smoke, and carbon monoxide in our homes. Kuech teamed up with professors Arthur Ellis from the University's chemistry department and Luke Mawst to change the surface of the light-emitting structure, making it chemically sensitive. The altered structure was then integrated onto a chip with a nearby detector stem where the emitter and detector communicate. "The structures are designed for optimizing the amount of surface area relative to the overall volume of the LED," says Ellis. "This enhances our ability to adsorb analytes and convert the adsorbtion to an optical signal," he explains. In addition to detecting the presence of chemicals, they also were sensitive to the amount of a given chemical present in the air. For more information, contact Ellis at (608) 262-0421.
The implementation of a new diesel fuel standard in the US has considerably improved the environmental performance of diesel vehicles. The Environmental Protection Agency (EPA) says that the new ultra-low sulfur diesel (ULSD) fuel has combined with other improved technologies to reduce diesel's particulate matter (PM) emissions by 99%.
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