Two years ago, Chinese scientists coated one side of a flag with a thin sheet of nanotubes, then played a song using the flapping sheet-coated flag as a speaker.
It was a demonstration of flexible speaker technology, in which nanotubes can be made to generate sound waves via a thermoacoustic effect – every time an electrical pulse is sent through the microscopic layer of nanotubes, it causes the air around them to heat up, which in turn creates a sound wave. Now, an American scientist has taken that technology underwater, where he claims it could allow submariners to detect other submarines, and to remain hidden themselves.
Research scientist Ali Aliev, of the University of Texas at Dallas, has determined that the low-frequency sound waves created by carbon nanotube sheets can be used by sonar systems to determine the location, depth, and speed of underwater objects. Aliev and his team also determined that the sheets could be tuned to transmit specific frequencies that would cancel out certain noises… noises such as those that a submarine makes while passing through the water, for instance.
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- Submarines could use new nanotube technology for sonar and stealth (nanotechweb.org)