At Stevens Institute of Technology, Dr. Alexander Sutin is developing a non-lethal weapon for protecting ports from underwater divers with malicious intentions -- an acoustic device that overwhelms them with the amplified sound of their own breath.
The technique may offer Homeland Security and the Navy a kinder, gentler method of non-lethal diver deterrent, an alternative to deadly underwater explosive charges or loud underwater sirens, which may impact marine life. His latest research will be presented by co-author Dr. Yegor Sinelnikov in a paper at the Acoustical Society of America's 2nd Pan-American/Iberian Meeting on Acoustics in Cancun, Mexico, held on November 15-19.
The idea is to detect the diver's breathing passively instead of using an active acoustic technology like a sonar ping. Dr. Sutin, a Research Professor at Stevens Center for Maritime Systems, has recently returned from Holland, where he and a team of Stevens and Dutch scientists investigated passive acoustic methods of diver detection.
"Many fish can produce similar signals to divers on active sonar, but fish do not breathe like humans," says Sutin. "Passive methods based on the breathing of a diver are such simpler and offer a much better detection rate."
The next step will be to develop a method to isolate a narrow band of the breathing sound and radiate it back to the diver. Using a technique called Time Reversal Acoustics (TRA), the scientists hope to produce an amplified beam of sound loud enough to overwhelm an intruder but focused enough to spare the surrounding wildlife. TRA has been successfully used to amplify acoustic signals to the level enough to destroy kidney stones.
The talk, "Time reversal acoustic approach for nonlethal swimmer deterrent" by Dr. Sinelnikov will be at 2:35 p.m. on Tuesday, November 16.
An abstract is available online: http://asa.aip.org/web2/asa/abstracts/search.nov10/asa291.html
Dr. Sutin and Dr. Sinelnikov have also written a lay-language paper that describes this research in greater detail. It is available upon request and will be posted to ASA's virtual press room shortly before the meeting: http://www.acoustics.org/press/