New Sonar Technology Reveals City-size Schools of Fish

Low-frequency sound waves improve ocean sensing

11 min read
New Sonar Technology Reveals City-size Schools of Fish
Photo: Fred Bavendam/Getty Images

Early on a May morning back in 2003, I was on the research vessel Oceanus some 200 kilometers south of Long Island, N.Y., searching for something I had been chasing for years. It wasn't a white whale, but it was just as alive—and a whole lot bigger.

My scientific colleagues and I had jokingly referred to the enigmatic thing we were seeking as a UFO—for "unidentified floating object." To find our elusive prey, we had engineered a newfangled sonar system that operates at relatively low frequencies and installed it on Oceanus, which is operated by the Woods Hole Oceanographic Institute. After days at sea, we finally got our big break—strong echoes emanating from about 20 km south of our ship, where the water was roughly 100 meters deep. On our sonar displays, it looked as though something the size of Manhattan was perched near the edge of the continental shelf.

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Before Ships Used GPS, There was the Fresnel Lens

This bright idea revolutionized lighthouses and saved lives

3 min read
 A Fresnel lens at the Seguin Island Light Station in Maine.

The Fresnel lens used in the Seguin Island Light Station in Georgetown, Maine.

Edwin Remsberg/AP

Ships today use satellite-based radio navigation, GPS, and other tools to prevent accidents. But back at the beginning of the 19th century, lighthouses guided ships away from rocky shores using an oil lamp placed between a concave mirror and a glass lens to produce a beam of light.

The mirrors were not very effective, though, and the lenses were murky. The light was difficult to see from a distance on a clear night, let alone in heavy fog or a storm.

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A novel device covers a wider range of frequencies and could boost 5G, radar, and quantum computers

3 min read
Illustration shows a gold surface marked to show non-overlapping clock generator 12.5% duty cycle clocks and to the left 2GHz cock input. Rising from 4 sections each containing 4 triangles are 12 cylinders .

Conceptual diagram of the Floquet TI implemented in a 45 nm silicon-on-insulator CMOS process.

CUNY/Nature Electronics

Novel devices known as photonic topological electromagnetic circuits may one day support 5G wireless broadband networks and advanced radar systems, a new study finds.

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Download this free whitepaper to learn how battery energy storage up to 1500 VDC can deliver power efficiencies and cost reductions

1 min read

The explosive growth of the battery energy storage industry has created a need for higher DC voltages in utility-scale applications.

Download this free whitepaper and learn how you can achieve a smooth transfer of power, efficiencies and cost reductions with battery energy storage system components up to1500 VDC.