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NEW YORK CITY - Whether it's the "soul of a new machine" or food for the soul, engineers probably played an important role in its creation. From microchips to potato chips, engineers have had a hand in nearly every part of our everyday work-and play. National Engineers Week, February 22-28, celebrates these achievements. What do microchips and potato chips have in common? Well, there's similar terminology - chips and wafers, to name two. But, more importantly, noted Cheryl Oliver, a chemical engineer working for Texas Instruments: "Both require a chemical engineering tool kit of knowledge-including thermodynamics, heat transfer, chemistry, and process control." There's a lot more than meets the eye in developing the perfect potato chip. According to chemical engineer William E. Lee III, the ear is also key. "Auditory information is important when assessing food," he told a reporter for Discover magazine. To prove just how important, Lee ran experiments in which subjects wore white-noise headphones to shut off any auditory feedback as they ate. What he found was that "the eating experience becomes boring more quickly - or remains exciting less long." Lee's work has ranged from measuring the crispness of chips by analyzing the airborne sounds of the crunch (fresher samples were louder and emitted higher- frequency sounds that stale samples) to identifying "perceived mouth location" of snack foods. "If the food shows up in the middle of the mouth and the person is using his or her tongue for compression, that means the product is doughy-not the consistency you want," he explained. "With a salty snack, we want to maximize teeth time and minimize tongue time." Lee is currently researching the effects of aging on the sense of taste. "Older people perceive things as less sweet than younger people. Everything to them tastes bland, which discourages them from eating" at a time of life when nutrition is particularly important. By charting differences in perception, new food products could be developed that would appeal to the taste buds of seniors and encourage them to eat Engineers are also responsible for the development and manufacture of microchips -the heart of all electronic devices from a simple greeting card to high-powered Cray computers. Microchips begin as molten silicon which is formed into a solid crystal, sliced into wafers, polished, and then cut into the familiar squares. Although a plethora of engineering skills are needed to accomplish all these steps, it is at the point where the chips become integrated circuits that the truly remarkable engineering is done. To etch increasingly complex commands - some chips now carry 64 megabits of memory - each circuit on the chip must undergo a complex photoetching process. This process provides the circuit with an electrical "roadmap" for commands. And, a few dozen to several thousand of these circuits can be placed on each wafer. Individual devices (such as resisters and transistors) placed on the wafer during doping are connected by a series of metal layers. Because of the incredible advancements in chip technology, chip heat removal requirements have greatly increased. As smaller sized components carry more commands, the heat generated by chips has soared. Heat fluxes-the variations in temperatures within the chip-can often reach several thousand degrees- comparable to the thermal loading experienced by reentry vehicles such as that of the Space Shuttle. As a result, proper packaging, using basics of heat transfer and thermodynamics are important. But engineers do much more than just these chips. You can bet that engineers are also involved in producing all kinds of other chips-including the plastic ones used in casinos. Remember that when you cash your winnings in!
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National Engineers Week Foundation
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