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The Cutting Edge: COMPUTING / TECHNOLOGY / INNOVATION : System May Get Fast Trains Back on Track

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High-speed trains powered and levitated by magnets have turned out to be the Little Engine That Couldn’t. High construction costs and the problem of obtaining rights-of-way for new tracks have stalled attempts in the United States to get “maglev” trains off the ground, as it were.

Enter Seraphim, a concept for a high-speed, magnetically powered train that does not levitate, runs on already-laid track, and is relatively inexpensive to build. Seraphim, developed by scientists at Sandia National Laboratories in Albuquerque, N.M., is a spinoff from technology created in the late 1980s for the Strategic Defense Initiative Organization to shoot satellites into space.

The train Sandia envisions would be the fastest in the United States, traveling at 200 miles per hour, or twice the maximum for commuters on the corridor between Boston and Washington. That’s slower than the maglev trains under construction in Germany and Japan, which are expected to reach 300 m.p.h. but which require special tracks.

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Unlike maglev trains, which travel with no engines aboard, the proposed Sandia train would carry a gas turbine that powers, or sends pulses into, on-board electromagnets. The pulsed magnets induce reversed electric currents in a series of aluminum plates bolted to or near the track. These currents create their own magnetic fields that oppose those of the train. With the aid of optical sensors, the magnetic fields pulse on just as the magnets pass the midpoint of the aluminum plates.

The repulsion propels the train forward. (Slow-moving shuttle trains such as those in the Dallas airport use a similar method but only achieve speeds of 30 m.p.h.) The Sandia train would ride on non-powered wheels made of steel or composite materials. The cost to build the Sandia system would be one-quarter of what a maglev system would be, and it has the additional advantage of permitting old-style and new-style trains to travel on the same tracks. Having built a working model, researchers are now applying for funding to power an actual train.

One Man’s Problem Is Another’s Delicacy: In the U.S. Corn Belt, corn smut, a black mushroom-like growth that covers corn ears, is a nuisance that reduces yields--especially of sweet corn--and can lead processors to refuse to accept tainted corn.

Efforts to develop sweet corn varieties that resist corn smut have led Jerald Pataky, a University of Illinois plant pathologist, into an unusual alliance with Mexican researchers and processors who actually want to improve the growth of this nutrient-packed fungus.

In Mexico the fungus is known as huitlacoche and is considered a delicacy. The Aztecs ate it, as do diners in trendy restaurants in the United States, where it sells under names such as Mexican truffles or caviar azteca. Some recipe books devote sections on using huitlacoche in soups, salads, pies and puddings--even in ice cream.

Huitlacoche, it turns out, is high in carbohydrates and fiber, low in fat, calories and cholesterol, and higher in protein than other maize or cereal grains. In trying to develop inoculation techniques for screening corn for resistance to the fungus, Pataky had to produce the fungus. Now, Mexican researchers, along with canning companies that are sponsoring the project, are using the same techniques that Pataky developed to mass produce huitlacoche as a cash crop.

Pinning Down Information: Medieval scholars supposedly argued long and hard about how many angels could dance on the head of a pin. In our time, a key area of research revolves around how much information can be crammed into the smallest space.

The Los Alamos National Laboratory recently moved to the head of the class when it unveiled a new storage technique that can get four sets of encyclopedias on an inch-long steel pin. That’s 180 times more information than can be put on a CD-ROM. What’s more, researchers at the Los Alamos, N.M., lab say, 5,000 years from now people will be able to read the information etched onto the pins without interpretive devices that convert computer data into language or pictures.

The High-Density Read-Only Memory, or HD-ROM, uses a specially modified, focused-ion beam developed at the Los Alamos’ Materials Science and Technology Division. The writing process, called sputter etching, removes material by atomic collisions. The beam--which can write features as narrow as 150 billionths of a meter (a distance equal to about 560 atoms)--is controlled by a computer.

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Much like a dot-matrix printer, it can thus etch the 1s and 0s of computer code, such as those written on CD-ROM, as well as letters, numbers or graphical images. These varied formats can coexist on the same HD-ROM. A souped-up version of a commercially available atomic force microscope reads the inscribed data. For computer data, the HD-ROM can describe the instructions needed to read the data, in a format humans can read.

And the pins, which can be made of stainless steel, iridium or other lasting materials, should have longer life spans than magnetic storage methods. The researchers have applied for patents and are looking for commercial partners.

Throttle Back: A novel throttle developed by a University of Southern California mechanical engineer could improve automobile gas mileage by more than 10% without sacrificing horsepower. Paul D. Ronney, who developed the new thermal throttle, says engines with such systems also produce exhaust that is far lower in a major contributor to air pollution--oxides of nitrogen or NOx--than those with conventional throttles.

The normal way to control the power output of a gasoline engine is to regulate the amount of air into the engine. The throttle works as a gate that partially closes the airway. Thus when a driver steps on the gas, he or she is really “stepping on the air,” opening this gate to allow more air into the combustion chamber. Misfires occur when the mixture of fuel to air falls below a certain ratio.

But if the fuel-air mixture is preheated before it is drawn into the engine, thus reducing the amount of heat needed to raise the mixture to the combustion point, the engine could run on a much leaner mixture. In Ronney’s throttle, a heat exchanger takes excess heat from the engine exhaust to preheat the mixture. Ronney hopes that with the addition of just two new parts, existing engines can be retrofitted inexpensively. Ronney has tested his thermal throttle on a retrofitted engine in the laboratory, but not yet in a moving car.

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