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The Cutting Edge: Computing / Technology / Innovation : IN DEVELOPMENT : Harnessing Energy on Solar Film

Converting sunlight into electricity may someday be as simple as buying a roll of what looks like plastic wrap at the local hardware store, stretching it over a frame and plugging in a couple of wires.

A joint research effort to develop such a “solar cell on a roll” has been announced by Advanced Research Development Inc. of Athol, Mass. and the Department of Energy’s Argonne National Laboratory. The three-year, $1.8-million project aims to develop solar energy technology that uses a film instead of layers of semiconductors to convert light into electric power.

The project would incorporate light-activated molecules developed by Argonne into an electrically conductive film developed by ARDI. Argonne’s molecules are based on perylene dyes, which are used in photocopying and liquid crystal displays. While these molecules convert solar energy into electrical energy with greater than 99% efficiency, it is not clear yet how much efficiency will be lost when the molecules are coupled to the film.

Mama-San, Phone Home: In the United States, cellular telephones and pagers are generally wielded by the young and the restless--business people who need to stay in constant touch with home and office. In Japan, however, portable telephone technology may soon be deployed to help the old and the lost.

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Faced with a rapidly aging population--forecasts are that by 2024, one in every four Japanese will be 65 or older--the Ministry of Posts and Telecommunications is concerned about the problem of how to locate elderly people who may wander off and become lost. One proposal is to equip elderly relatives with a personal handy phone.

PHP technology would allow cordless telephones to be used outside like portable cellular phones. In the search system envisioned, a worried relative would call the handy phone carried by a lost elderly person. Even if the person did not respond, the phone would send an automatic signal to a nearby land station equipped for PHP services and searchers would be sent out. Land stations are expected to be situated at intervals covering a radius of 100 meters.

The ministry is also testing a pager system that would flash a light when it received calls and send a message four times, asking passers-by to telephone the caller’s number. In tests in Tokyo, however, passers-by had trouble hearing the pager..

Haste Makes Better Aluminum: Aluminum car parts have been something of a Holy Grail for the auto industry because they are very light and thus can cut the weight of a car and improve gasoline usage. But the components have traditionally been very difficult and costly to fashion, limiting their use to only the most expensive cars.

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Researchers at the Center for Materials Research at Ohio State University in Columbus have now resurrected technology from the 1950s and ‘60s that holds the promise of forming aluminum parts much more easily and cheaply.

Called “high-rate forming,” the technique slams metal into a die at velocities of about 200 m.p.h., which makes it possible to take advantage of the effects of inertia. At high speeds, inertia--the tendency for matter in motion to move at a constant velocity--coaxes the metal to stretch gradually rather than tear.

Also, the momentum makes the metal act like a piece of clay thrown against a wall, causing it to spread easily without fracturing. Thus metals can be stretched two to five times farther than sheet metal formed using standard techniques.

Light-Emitting Plastic: Materials that turn light into electrical signals and vice versa show up almost everywhere in daily life. Fax machines, copiers, computer monitors, fluorescent lighting, solar cells--even the human eye--are based on these so-called opto-electronic materials, such as gallium arsenide.

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Opto-electronic polymers, inexpensive and versatile plastics, have long existed as low-cost and convenient alternatives to conventional materials, but they have always had serious drawbacks. For one, engineers have not been very successful at controlling the amount and color of light they emit. And the polymers are inefficient, wasting a lot of energy by converting only a small fraction of one form of energy into the other.

But now engineers at the University of Rochester have discovered that by blending a second type of polymer with the original, they can prevent the formation of pairs of molecules, or eximers, that do not emit light efficiently, and instead create a material that emits light very efficiently.


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