(Press-News.org) Rolf Mueller, an associate professor of mechanical engineering in the College of Engineering at Virginia Tech, has developed a prototype of a dynamic sonar system inspired by horseshoe bats.
The prototype was presented Wednesday (May 20) at the Acoustical Society of America meeting in Pittsburgh, Pennsylvania. The principles used in its design could eventually lead to sonar systems much more effective than the best arrays available today.
Because bats use a form of biological sonar called echolocation to navigate and hunt in the dark, they are natural models for man-made sonar systems.
Horseshoe bats' sonar is especially sophisticated.
"They among the most maneuverable fliers, and they hunt in the most confined, complicated spaces," Mueller said.
To pick out a moth's fluttering wings from the canopy of leaves in a dense thicket, for example, horseshoe bats have the ability to adjust their sonar pulses to pick out small frequency shifts caused by the wing motion of their prey.
The bats emit ultrasonic pulses through their noses, which are outfitted with intricate folds of soft tissue called noseleaves.
The noseleaves act like megaphones to amplify the sound, but they also modify their shape to fine-tune the characteristics of the emitted pulses.
The bats' ears, which receive the incoming echoes, are also dynamic, adjusting their shape and angle to filter the sound more efficiently. These precise adjustments happen within one tenth of a second -- about three times faster than a human can blink his eye.
These adjustments are part of what allow the bats to get more detailed data from just two receivers than modern naval sonar systems can collect with several hundreds.
Mueller's prototype is the first sonar system that -- like the horseshoe bat -- has both a dynamic emitter and dynamic receivers.
To develop their model, Mueller and his team studied a colony of about 30 bats. They tracked the movements of their ears and noseleaves with a combination of high-speed video, ultrasonic microphone arrays, and laser Doppler vibrometry.
The vibrometer directs a laser beam at a moving object, and uses the Doppler shift of the reflected beam to measure the amplitude and frequency of the object's vibration -- much the same way that the bats use the Doppler shift of its reflected ultrasound pulses to track their prey.
This data allowed Mueller to build three-dimensional computer models of the bats' ears and noseleaves, and study both their structure and their key movements.
"Our goal is to reproduce all the features that we are sure have a function, or that we think might have a function. Then we'll trim it down," Mueller said.
The current prototype is two and a half times the size of a common horseshoe bat species. Four motors control the ears and noseleaves, which are made of flexible rubber. The motors can carry out these adjustments about as fast as the real bat.
In nature, the bats' flight adds an extra layer of complexity: to compensate for their own motion, bats adjust the frequency their outgoing sonar pulses so that the reflected ultrasound will fall in the optimum range for detection. To study how to replicate this capability, Mueller plans to mount his prototype system on a small drone.
INFORMATION:
Mueller is the director of the Center for Bioinspired Science and Technology at Virginia Tech, which is partially supported by the Institute for Critical Technology and Applied Science.
The center's research, which blends engineering and biology, covers topics including swarming behavior, the flight of gliding snakes, and owls' soundless wingbeats.
Paris, France - May 20, 2015 - Data from the ILUMIEN II trial found that guidance from optimal coherence tomography (OCT) was associated with comparable stent expansion as guidance from intravascular ultrasound (IVUS) in patients undergoing percutaneous coronary intervention (PCI). Results from the study were presented today at EuroPCR 2015, the official annual meeting of the European Association for Percutaneous Cardiovascular Interventions.
Coronary stents must be optimally deployed with full lesion coverage and complete stent expansion to optimize outcomes. Less than ...
When it comes to keeping online information safe from hackers and other criminals, it's up to the individual user to keep his or her data secure.
Unfortunately, many Internet users don't take that responsibility seriously, thinking that's the job of the Internet provider or even the company that manufactured their computer.
The end-user is often the "weakest link" in the Internet safety chain, said Saleem Alhabash, a Michigan State University faculty member who is part of a team that researches ways of making the Web safer for its users.
The team's conclusion: Internet ...
A common mutation in a gene that regulates cholesterol levels may raise the risk of heart disease in carriers, according to a new UConn Health study.
Researchers examined a mutation called the missense rs4238001 variant, which alters the type of protein made by the gene SCARB1, and thereby the body's cholesterol regulation.
The study, led by Annabelle Rodriguez-Oquendo, an endocrinologist at UConn Health, was based on information about more than 5,000 people who participated in the Multi-Ethnic Study of Artherosclerosis in major American cities from 2000 to 2002. ...
The fossils of the first dinosaur fossil from Washington State were collected along the shores of Sucia Island State Park in the San Juan Islands, and described in a study published May 20, 2015 in the open-access journal PLOS ONE by Brandon Peecook and Christian Sidor from the Burke Museum of Natural History and Culture at the University of Washington.
The fossils were discovered while collecting ammonite fossils (a nautilus-like creature) from a marine rock unit known as the Cedar District Formation. The authors of the study describe the fossil as the partial left ...
Burke Museum paleontologists have published a description of the first dinosaur fossil from Washington state. The fossil was collected by a Burke Museum research team along the shores of Sucia Island State Park in the San Juan Islands.
Burke Museum researchers discovered the fossil while collecting ammonite fossils (a creature with a spiral shell) from a marine rock unit known as the Cedar District Formation. The researchers first noticed a small section of exposed bone on the surface of the rocks, then returned with a team of paleontologists to help excavate the fossil ...
Prolonged paracetamol use by pregnant women may reduce testosterone production in unborn baby boys, research has found.
Researchers say their findings could help to explain reported links between paracetamol use in pregnancy and reproductive health problems in young boys.
Paracetamol is the primary medicine used for managing pain and fever during pregnancy.
The authors recommend that expectant mothers should follow existing guidelines that the painkiller be taken at the lowest effective dose for the shortest possible time.
Testosterone, produced in the testicles, ...
A national survey reveals that only one in ten Australians report being told about the risk of overdiagnosis by their doctors, according to research published today in the scientific journal PLOS ONE.
The increasingly recognised problem of overdiagnosis happens when someone is diagnosed with a disease that will never cause them any harm, often as a result of healthy people being screened for diseases such as breast or prostate cancer. Overdiagnosis can be harmful due to unnecessary labelling and treatment.
The telephone survey (mobile and landline) of 500 Australians ...
WASHINGTON (May 20, 2015) - Despite challenges, it is feasible to collect and study the quality of outpatient cardiovascular care in a resource-limited environment like India, according to a pilot study published today in the Journal of the American Heart Association. Researchers used the American College of Cardiology's PINNACLE India Quality Improvement Program registry to examine performance measures and outline areas for further improvement in cardiovascular care delivery.
There is a growing burden of cardiovascular disease in India, but only limited data is available ...
(MEMPHIS, Tenn. - May 20, 2015) Researchers led by St. Jude Children's Research Hospital scientists have developed a second-generation antibiotic that shows early effectiveness against common bacterial infections that pose a serious health threat to children and adults. The findings appear today in the scientific journal Science Translational Medicine.
The study marks the second time in recent years that St. Jude researchers have created promising antibiotics by changing the chemical structure of an old antibiotic named spectinomycin. Spectinomycin is a safe, but weak ...
TORONTO, May 20, 2015 - The use of personalized music playlists with tempo-pace synchronization increases adherence to cardiac rehab by almost 70 per cent--according to a study published in Sports Medicine -Open.
"Cardiac rehab has been proven to improve long-term survival for someone who's had a heart event by 20 per cent," said Dr. David Alter, Senior Scientist, Toronto Rehab, University Health Network, and Institute for Clinical Evaluative Sciences. "Our challenge is there is a high drop-out rate for these programs and suboptimal adherence to the self-management of ...
