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Monday, January 12, 1998
SCIENCE WATCH
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 n fields ranging from cell biology to the exploration of space,
scientists these days increasingly think in smaller dimensions.
The growing emphasis on "nanotechnology" (from the Greek term for "billionth") has been punctuated over the last few weeks by news in a number of areas. There are proposals for satellites smaller than a baseball, and tiny devices already exist that are the size of a grain of sand and can move objects weighing a pound. The mother of this inventive effort is, as usual, scientific necessity. Mapping DNA sequences in plants and animals, building ever faster computers, and engineering ways to attack disease on a genetic level require new tools and techniques that can manipulate nature on the tiniest scale. And in some cases, scientists are learning simply that smaller is better. At Los Alamos National Laboratory, atop the Jemez Mountains of New Mexico, scientists are designing satellites that weigh no more than half an ounce and measure about 3 inches in diameter. They believe hundreds of these micro-satellites deployed between the Earth and the sun could measure the solar wind so precisely they could foretell electromagnetic disturbances that might disrupt communications around the globe. These include sunspot eruptions that create high static levels in radio transmissions. Mark Tilden, an engineer who pioneered the development of tiny robots that use small electrical forces instead of motors to move themselves, believes the tiny satellites would be less vulnerable to the vicissitudes of space than larger, more complex units. Such phenomena as the solar wind and the Earth's magnetic field can play havoc with the control systems and instruments aboard most satellites--which is partly why nearly half of them fail--but the small birds Tilden wants to build would actually use those forces instead of trying to avoid them. The satellites would use solar light to determine their position in relation to the sun, and the Earth's magnetic field for the torque needed to orient themselves. "Instead of designing systems that withstand their environment, we are engineering systems that rely on their environment," says Kurt Moore, a colleague of Tilden at Los Alamos. The satellites could also be used to make detailed images of the Earth, the scientists say. Each satellite could be assigned a small target area, and ground crews could combine those individual pieces into a precise picture of the planet. Meanwhile, at the Weizmann Institute of Science in Rehovot, Israel, researchers believe they have come up with a valuable new tool to help geneticists trying to unravel the genetic code of plants: tiny tomatoes. Weizmann's Avraham Levy didn't have the time, or the room, to grow the 100,000 tomato plants he needed for his project to identify every gene in the tomato genome. He figured he could grow only about five plants per square meter, which would require a greenhouse of gargantuan proportions. So he borrowed a plant initially developed to help city dwellers with limited gardening space. "Micro-Tom," as Levy calls it, is so small he can grow 1,000 in a square meter, and better yet, it produces fruit twice as fast as larger varieties. That means he can harvest four generations per year instead of two. The goal of the research, according to Levy, is to identify genes and their functions so that plant breeders eventually can select genetic material to customize fruits and vegetables. Although he is working with tomatoes, he says the technique could be applied to a range of plants, proving that small can be very efficient. Scientists at Sandia National Laboratory have taken that concept to the extreme. They have been working for years with "microengines," machines about the size of a grain of sand. These tiny motors are capable of doing work, but they have been limited in their application because they are so small and weak that they can't do as much work as desired. So researchers at Sandia have come up with "microtransmissions," which are also about the size of a grain of sand. Like an automotive transmission that provides the right gear ratio needed for the motor to move the car, these microtransmissions increase the power of a microengine by a factor of about 3 million, theoretically making it possible for the tiny device to move a one-pound object. Researchers Steve Rodgers and Jeff Sniegowski developed the machines for use as nearly invisible locks on nuclear weapons, but they see many other possible applications as well. They could be useful aboard satellites, or aircraft, or even in surgical applications where a large force is needed in a very small area. Similar research in nanotechnology is going on at many labs and universities as scientists grapple with a world that, for them, just seems to get smaller and smaller.
Copyright Los Angeles Times
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