- News Home
5 December 2013 11:26 am ,
Vol. 342 ,
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
- 5 December 2013 11:26 am , Vol. 342 , #6163
- About Us
Voilà! A Gas Becomes Electric
19 August 2004 (All day)
Scientists have converted a gentle flow of gas directly into an electric current by flowing common gases like oxygen, nitrogen, or argon over a special kind of semiconductor. Although physicists say the technique has a way to go before it can be applied, they envision its being used for developing tiny measuring devices or to make tiny generators.
Last year in Science, Ajay K. Sood and Shankar Ghosh of the Indian Institute of Science in Bangalore and colleagues reported inducing an electrical signal by flowing water over single-walled nanotubes (Science, 14 February 2003). They were curious whether similar currents could be generated when a gas was used.
In this latest experiment, the physicists released pure compressed gas over a 3-millimeter-long semiconductor set on an incline and onto carbon nanotubes. The semiconductors the scientists used were "doped," meaning they'd been impregnated with certain impurities, such as boron or phosphorus, which would enhance their conductive properties. Sometimes the team released gas traveling a leisurely average walking speed of a few kilometers per hour; other times, they let the gas flow 100 times faster. Each time, they got a measurable electrical signal; when metals such as platinum replaced the semiconductor strip, the effect disappeared, they report in the 17 August online Physical Review Letters.
Creating an electrical current with a gas is possible in part because when gas strikes an inclined surface, it produces a pressure gradient, similar to the effect that keeps airplanes in the air. This pressure gradient in turn produces a temperature differential on the surface, which prompts production of a tiny electrical current.
"The device is potentially very useful," says Narayanan Menon, an experimental physicist at the University of Massachusetts, Amherst, who says he's surprised that no one has done this experiment before. He could envision the approach's being used to create new flow sensors or electric generators without moving parts.