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Warning: Red Means `Refrozen'

Developments to Watch


SUPERMARKETS DON'T HAVE SPECIAL SECTIONS marked "refrozen," but they probably should. Accidents happen. Manufacturers don't always keep fridges cold enough. Goods being delivered sometimes sit on a curb too long. Either way, consumers may not know about it until they eat the product.

A temperature sensor from Sandia National Laboratories may have a solution. Invented by researchers David Martinez and Mo Shahinpoor, it consists of a shape-memory alloy of nickel and titanium on a piece of paper the size of a postage stamp. One end of the wire is anchored to the paper. The other is tethered to a green, lentil-size shutter that covers a red dot. When the temperature rises above 32F, the wire shrinks, pulling the green shutter into a tiny pocket and exposing the red dot underneath (picture). Refreezing will not bring the green shutter back out.

Food processors are leery about the new sensors. Jenny Scott, a senior director of food safety programs at the National Food Processors Assn. in Washington, says refreezing poses few health hazards because most cases occur in too short a time frame to allow bacteria to proliferate. But Scott admits there are "quality issues." And that's exactly what the sensor will address. Sandia's Shahinpoor says that the sensors, produced in volume, will cost just a few cents each. So for pennies, manufacturers who want to reassure finicky customers will be able to put proof right on the label.Nellie AndreevaReturn to top


FOR NEARLY A DECADE, researchers have been able to build transistors tiny enough to switch on and off with the movement of a single electron. These switches promise "quantum" computers the size of a thumbtack with supercomputer powers. But progress has been disappointingly slow--mainly because of a lack of tools for analyzing the workings of such teensy transistors.

Scientists at Yale University say they have solved that problem--and, in the process, created an ultrafast single-electron transistor. The breakthrough involves inducing a tiny region in the transistor to "resonate" as each electron arrives. This creates a radiolike signal that allows the movements of individual electrons to be tracked. The resonance also gives an extra push to electrons moving through the switch. That makes the transistor blindingly fast--1,000 times speedier than any previous device. "Our invention is an enabling technology for developing tomorrow's quantum computers," says Daniel E. Prober, professor of applied physics at Yale.

But the first applications are likely to be in astronomy and microscopy. The transistors can be used to amplify light coming from distant stars or microscopic samples. Their speed and sensitivity enable them to relay both the light's intensity and its wavelength. Thus, scientists could collect data about the chemical composition of stars or specimens while they record visual images--without the need for spectrographic instruments.EDITED BY OTIS PORTReturn to top


DESIGN ENGINEERS WASTE precious time searching catalogs for some existing part to include in a design. Bruno Valdes, a staff engineer with IBM's Storage Products Div. in San Jose, Calif., dubs such catalog searches "the most time-consuming and distracting part of the job."

That's why Valdes jumped at a new alternative: a searchable online catalog from InPart Design Inc., a startup in Saratoga, Calif. Unveiled this year, the DesignSuite catalog already contains more than 150,000 digital models of standard parts--from gears and bushings to pumps and electric motors--produced by two dozen suppliers.

The software for accessing DesignSuite can be downloaded from the Internet ( and licensed for as little as $1,000. Retrieving a digital model to plug into a design costs $20, a mere fraction of what it costs to redraw parts from a paper catalog. IBM's Valdes figures the software can pay for itself after an engineer buys fewer than 10 models.EDITED BY OTIS PORTReturn to top

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