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Ocean Gliders Measure Melting Polar Ice

The rapidly melting ice sheets on the coast of West Antarctica are a potentially major contributor to rising ocean levels worldwide. Although warm water near the coast is thought to be the main factor causing the ice to melt, the process by which this water ends up near the cold continent is not well understood. Using robotic ocean gliders, Caltech researchers have now found that swirling ocean eddies, similar to atmospheric storms, play an important role in transporting these warm waters to the Antarctic coast—a discovery that will help the scientific community determine how rapidly the ice is melting and, as a result, how quickly ocean levels will rise. "When you have a melting slab of ice, it can either melt from above because the atmosphere is getting warmer or it can melt from below because the ocean is warm," explains lead author Andrew Thompson, assistant professor of environmental science and engineering. "All of our evidence points to ocean warming as the most important factor affecting these ice shelves, so we wanted to understand the physics of how the heat gets there." Because the gliders are small—only about six feet long—and are very energy efficient, they can sample the ocean for much longer periods than large ships can. When the glider surfaces every few hours, it "calls" the researchers via a mobile phone–like device located on the tail. The communication allows the researchers to almost immediately access the information the glider has collected. Like airborne gliders, the bullet-shaped ocean gliders have no propeller; instead they use batteries to power a pump that changes the glider's buoyancy. When the pump pushes fluid into a compartment inside the glider, the glider becomes denser than seawater and less buoyant, thus causing it to sink. If the fluid is pumped instead into a bladder on the outside of the glider, the glider becomes less dense than seawater—and therefore more buoyant—ultimately rising to the surface. Like airborne gliders, wings convert this vertical lift into horizontal motion. Source Also: Learn about Remote Sensing of Ice Sheets and Snow.

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Microbot Muscles Self-Assemble and Flex

In a step toward robots smaller than a grain of sand, University of Michigan researchers have shown how chains of self-assembling particles could serve as electrically activated muscles in the tiny machines."We are inspired by ideas of microscopic robots," said Michael Solomon, a professor of chemical engineering. "They could work together and go places that have never been possible before."Solomon and his group demonstrated that some gold plating and an alternating electric field can help oblong particles form chains that extend by roughly 36 percent when the electric field is on.The team started with particles similar to those found in paint, with diameters of about a hundredth the width of a strand of hair. They stretched these particles into football shapes and coated one side of each football with gold. The gilded halves attracted one another in slightly salty water—ideally about half the salt concentration in the sports drink Powerade. The more salt in the water, the stronger the attraction.Left to their own devices, the particles formed short chains of overlapping pairs, averaging around 50 or 60 particles to a chain. When exposed to an alternating electric field, the chains seemed to add new particles indefinitely. But the real excitement was in the way that the chains stretched."We want them to work like little muscles," said Sharon Glotzer, the Stuart W. Churchill Professor of Chemical Engineering. "You could imagine many of these fibers lining up with the field and producing locomotion by expanding and contracting."SourceAlso: Learn about Microelectronic Repair Techniques for Wafer-Level Integration.

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NASA Technologists Advance Next-Generation 3D Imaging

Building, fixing, and refueling space-based assets or rendezvousing with a comet or asteroid will require a robotic vehicle and a super-precise, high-resolution 3D imaging lidar that generates the real-time images needed to guide the vehicle to a target traveling at thousands of miles per hour.A team of technologists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is developing a next-generation 3D scanning lidar — dubbed the Goddard Reconfigurable Solid-state Scanning Lidar (GRSSLi) — that could provide the imagery required to execute these orbital dances.Equipped with a low-power, eye-safe laser, a micro-electro-mechanical scanner, and a single photodetector, GRSSLi will "paint" a scene with the scanning laser. Its detector will sense the reflected light to create a high-resolution 3-D image at kilometer distances — a significant increase in capability over current imaging lidars that are effective only at meter distances.Just as important, the instrument is equipped with onboard "vision" algorithms that interpret the three-dimensional image returned by the lidar. The softwar estimates location and attitude of a target relative to the lidar.SourceAlso: Learn about NASA's Asteroid Redirect Mission.

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Cockroach Biobots Detect Sound

North Carolina State University researchers have developed technology that allows cyborg cockroaches, or biobots, to pick up sounds with small microphones and seek out the source of the sound. The technology is designed to help emergency personnel find and rescue survivors in the aftermath of a disaster.The researchers have also developed technology that can be used as an “invisible fence” to keep the biobots in the disaster area.“In a collapsed building, sound is the best way to find survivors,” says Dr. Alper Bozkurt, an assistant professor of electrical and computer engineering at NC State and senior author of two papers on the work.The biobots are equipped with electronic backpacks that control the cockroach’s movements. Bozkurt’s research team has created two types of customized backpacks using microphones. One type of biobot has a single microphone that can capture relatively high-resolution sound from any direction to be wirelessly transmitted to first responders.The second type of biobot is equipped with an array of three directional microphones to detect the direction of the sound. The research team has also developed algorithms that analyze the sound from the microphone array to localize the source of the sound and steer the biobot in that direction. SourceAlso: Learn about FINDER (Finding Individuals for Disaster and Emergency Response).

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Light Bending Material Facilitates Search for New Particles

Particle physicists have a hard time identifying all the elementary particles created in their particle accelerators. But now researchers at Chalmers University of Technology have designed a material that makes it much easier to distinguish the particles.

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Scientists Find Novel Way to Improve Laser Performance

Energy loss in optical systems, such as lasers, is a chief hindrance to their performance and efficiency and it occurs on an ongoing, frustrating basis. To help laser systems overcome loss, operators often pump the system with an overabundance of photons, or light packets, to achieve optical gain. But now, scientists from the School of Engineering & Applied Science at Washington University in St. Louis have shown a new way to reverse or eliminate such loss by, ironically, adding loss to a laser system to actually reap energy gains. In other words, they've invented a way to win by losing.

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1550 nm Pulsed Laser Diode

OSI Laser Diode, Inc. (LDI) (Edison, NJ) has introduced a 1550 nm pulsed laser diode with an integrated micro lens that delivers a far‑field beam pattern. The beam pattern's divergence is equivalent in both the Fast (perpendicular) and the Slow (parallel) axes of emission. The CVLL 350‑CL90 pulsed laser diode beam divergence (FWHM) is 8 x 8 degrees. The adjusted Far Field pattern offers high coupling efficiency when used with standard spherical lens systems. LDI's new device is RoHS compliant and operates in wavelengths ranging from 1530 nm to 1580 nm, with 1550 nm typical. The operating temperature is 25 degrees C, the pulse width is typically 150 nanoseconds, frequency is 5kHz, the drive current is at 75 W, and peak power is at 22 W.

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