News

Shape-Changing Wing Flap Reduces Drag and Noise

A milestone for the Adaptive Compliant Trailing Edge (ACTE) project at NASA's Armstrong Flight Research Center occurred with the delivery of two revolutionary experimental flaps designed and built by FlexSys of Ann Arbor, MI, for installation on the Gulfstream G-III Aerodynamics Research Test Bed aircraft. Researchers are replacing the airplane’s 19-foot-long aluminum flaps with advanced, shape-changing assemblies that form continuous bendable surfaces.

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Engineers Build 3D Acoustic Cloaking Device

Using little more than a few perforated sheets of plastic and a staggering amount of number crunching, Duke engineers have demonstrated a three-dimensional acoustic cloak. The new device reroutes sound waves to create the impression that both the cloak and anything beneath it are not there.The acoustic cloaking device works in all three dimensions, no matter which direction the sound is coming from or where the observer is located, and holds potential for future applications such as sonar avoidance and architectural acoustics.The materials manipulating the behavior of sound waves are simply plastic and air. Once constructed, the device looks like several plastic plates with a repeating pattern of holes poked through them. The plates are stacked on top of one another to form a sort of pyramid.The cloak must alter the waves’ trajectory to match what they would look like had they had reflected off a flat surface. Because the sound is not reaching the surface beneath, it is traveling a shorter distance and its speed must be slowed to compensate.To test the cloaking device, researchers covered a small sphere with the cloak and “pinged” it with short bursts of sound from various angles. Using a microphone, they mapped how the waves responded and produced videos of them traveling through the air.SourceLearn about an Acoustic Liner for Turbomachinery Applications.

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Programmable Metamaterial Damps Vibrations

Researchers from Empa and ETH Zurich have produced a material prototype that damps vibrations completely and specifically conducts certain frequencies.  The working model consists of a one-meter by one-centimeter aluminum plate that is one millimeter thick. The sheet-metal strip vibrates at different frequencies. In order to control the wave propagation, ten small aluminum cylinders (7 mm thick, 1 cm high) are attached to the metal. Between the sheet and the cylinders sit piezo discs, which can be stimulated electronically and change their thickness quickly. The model enables the researchers to control how waves are allowed to propagate in the sheet-metal strip. Such a “metamaterial” could fundamentally revolutionize mechanical engineering and plant construction. In the future, the material could react to current vibration readings and adapt its vibration properties at lightning speed. SourceAlso: See other Materials tech briefs.

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Handheld Camera Detects Nuclear Radiation

A handheld radiation camera developed by University of Michigan engineering researchers offers nuclear plant operators a faster way to find potentially dangerous hot spots and leaky fuel rods.The new 'Polaris-H' detector lays a gamma-ray map over an image of a room, pinpointing radiation sources with unprecedented precision. At least four U.S. nuclear power plants are using versions of the camera, which is now available commercially through the U-M spinoff company H3D."This technology enables people to 'see' radiation," said Zhong He, a professor of nuclear engineering and radiological sciences at U-M and CEO of H3D. "This should enable the early detection of leaks by locating abnormal radiation, a much better understanding of radiation sources to protect workers, and it could be a tool for the cleanup effort of nuclear waste and fallout, such as in Fukushima in Japan."SourceAlso: Learn about a Wide-Range Neutron Detector for Space Nuclear Applications.

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NASA Data Helps Growers During California's Drought

Following two consecutive years of drought conditions, 2014 is shaping up to be one of the driest years on record in California. Since 1982, the California Department of Water Resources (CDWR) has operated more than 140 monitoring stations that provide daily measurements of agricultural weather conditions and the amount of water lost to the atmosphere by a well-water grass surface. Data from this network is distributed through the California Irrigation Management Information System (CIMIS), operated by CDWR. To date, this information has been shown to have great value as a tool for irrigation managers to determine the water requirements for their crops.

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Researchers Mass-Manufacture Using Compostable Material

Researchers at Harvard's Wyss Institute have developed a method to carry out large-scale manufacturing of everyday objects — from cell phones to food containers and toys — using a fully degradable bioplastic isolated from shrimp shells. The objects exhibit many of the same properties as those created with synthetic plastics, but without the environmental threat. The process also trumps most bioplastics on the market today in posing absolutely no threat to trees or competition with the food supply.The Wyss Institute team developed its bioplastic from chitosan, a form of chitin, which is a powerful player in the world of natural polymers and the second most abundant organic material on Earth. Using traditional casting or injection molding manufacturing techniques, the researchers process the material so that it can be used to fabricate large, 3D objects with complex shapes. This advance validates the potential of using bioinspired plastics for applications that require large-scale manufacturing. The next challenge is for the team to continue to refine their chitosan fabrication methods so that they can take them out of the laboratory, and move them into a commercial manufacturing facility with an industrial partner.SourceAlso: Read other Manufacturing & Prototyping articles.

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Proposed Device Harvests Energy from Earth's Infrared Emissions

Physicists at the Harvard School of Engineering and Applied Sciences (SEAS) envision a device that would harvest energy from Earth’s infrared emissions into outer space.The research team is proposing something akin to a photovoltaic solar panel. Instead of capturing incoming visible light, however, the device would generate electric power by releasing infrared light.To show the range of possibilities, the group suggests two different kinds of emissive energy harvesters: one that is analogous to a solar thermal power generator, and one that is analogous to a photovoltaic cell. Both would run in reverse.The first type of device would consist of a “hot” plate at the temperature of the Earth and air, with a “cold” plate on top of it. The cold plate, facing upward, would be made of a highly emissive material that cools by very efficiently radiating heat to the sky. Based on measurements of infrared emissions in Lamont, Oklahoma (as a case study), the researchers calculate that the heat difference between the plates could generate a few watts per square meter, day and night.SourceAlso: Learn about the TIRS thermal infrared sensor.

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