The only mammals that can fly are also the only mammals with a larynx that flexes at ludicrous speed, a new study shows. As bats flip and whirl toward their prey, they chirp at an accelerating rate, increasing their echolocating calls to 160-190 chirps per second. This is possible because their laryngeal muscles can contract up to 200 times per second, researchers say.
Guide dogs are great, but vision-impaired people sometimes need to find their own way through complex environments. Instead of checking for obstacles with a trademark white stick, inventor Steve Hoefer has another idea: Use wrist-mounted sonar.
A new acoustic invisibility cloak made of a plastic metamaterial makes objects invisible to sound waves, researchers say. It could be used to shield ships from sonar, or build better soundproof walls for concert halls and other spaces. We’ve seen this idea before, but now Duke University researchers have actually built it.
Dolphins can understand more than 100 words, decipher human instructions and even use iPads to learn basic communication skills. But that’s kind of unfair on the part of us humans, don’t you think? Shouldn’t dolphins be able to ask for more smelt without learning our sign language or using our gadgets?
Bats — you know we love ‘em — have a remarkable ability to turn, swirl and dive on a dime while in mid-flight, dodging obstacles and grabbing food from the air. Engineers would like to give robots and autonomous vehicles this ability, and they’re turning to bat ears for inspiration.
Carbon nanotubes could provide better stealth technology for submarines, helping them to "see" other undersea objects while remaining invisible to enemy subs. A report in ACS Nano Letters details a new application of a previously-known property of sheets of carbon nanotubes just a fraction of the width of a human hair that nonetheless can generate sound and cancel out noise far better than current sound-generating tech.
A standard home audio speaker converts electrical signals into sound pulses in the air (via a somewhat cumbersome cone). Those sound waves in turn cause tiny variations in air temperature, as waves disrupt surrounding air. So, scientists reasoned, why not create sound waves through those temperature fluctuations themselves?
In 2008 researchers built a loudspeaker from carbon nanotubes that creates sound from this thermoacoustic effect. Now Finnish researchers have created a far more simple thermoacoustic device using tiny aluminum wires suspended over a substrate, opening thermoacoustics to a far broader range of applications.
Imaging an unborn fetus and and spotting a lurking submarine could both become much easier with the world's first acoustic hyperlens. The device manipulates imaging sound waves to provide an eightfold increase in the magnification power of technologies such as ultrasound and sonar.