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'Sensing Skin' Detects Damage in Concrete Structures

Researchers from North Carolina State University and the University of Eastern Finland have developed new “sensing skin” technology designed to serve as an early warning system for concrete structures, allowing authorities to respond quickly to damage in everything from nuclear facilities to bridges.“The sensing skin could be used for a wide range of structures, but the impetus for the work was to help ensure the integrity of critical infrastructure such as nuclear waste storage facilities,” says Dr. Mohammad Pour-Ghaz, an assistant professor of civil, construction and environmental engineering at NC State and co-author of a paper describing the work.The skin is an electrically conductive coat of paint that can be applied to new or existing structures. The paint can incorporate any number of conductive materials, such as copper, making it relatively inexpensive.Electrodes are applied around the perimeter of a structure. The sensing skin is then painted onto the structure, over the electrodes. A computer program then runs a small current between two of the electrodes at a time, cycling through a number of possible electrode combinations.Every time the current runs between two electrodes, a computer monitors and records the electrical potential at all of the electrodes on the structure. This data is then used to calculate the sensing skin’s spatially distributed electrical conductivity. If the skin’s conductivity decreases, that means the structure has cracked or been otherwise damaged.The researchers have developed a suite of algorithms that allow them to both register damage and to determine where the damage has taken place.SourceAlso: Learn about Designing Composite Repairs and Retrofits for Infrastructure.

Posted in: Electronics & Computers, Electronic Components, Electronics, Materials, Sensors, Detectors, Test & Measurement, Communications, Semiconductors & ICs, News

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New Strain Gauge Enables 'Soft Machines'

Purdue University researchers have developed a technique to embed a liquid-alloy pattern inside a rubber-like polymer to form a network of sensors. The approach may be used to produce "soft machines" made of elastic materials and liquid metals.Such an elastic technology could be used to create robots with sensory skin, as well as develop stretchable garments that interact with computers."What's exciting about the soft strain gauge is that it can detect very high strains and can deform with almost any material," said Rebecca Kramer, an assistant professor of mechanical engineering at Purdue University. "The skin around your joints undergoes about 50 percent strain when you bend a limb, so if you wanted to have sensory skin and wearable technology that tracks your movement you need to employ soft, stretchable materials that won't restrict your natural range of motion."SourceAlso: Learn about Thermal Properties of Microstrain Gauges.

Posted in: Materials, Metals, Plastics, Motion Control, Sensors, Machinery & Automation, Robotics, News

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Engineers Develop Ultrastiff, Ultralight Material

Engineers at MIT and Lawrence Livermore National Laboratory (LLNL) have developed a new ultrastiff, ultralight material. The material is based on the use of microlattices with nanoscale features, combining great stiffness and strength with ultralow density. The actual production of such materials is made possible by a high-precision 3-D printing process called projection microstereolithography.By using the right mathematically determined structures to distribute and direct the loads — the way the arrangement of vertical, horizontal, and diagonal beams do in a structure like the Eiffel Tower — the lighter structure can maintain its strength."We found that for a material as light and sparse as aerogel [a kind of glass foam], we see a mechanical stiffness that’s comparable to that of solid rubber, and 400 times stronger than a counterpart of similar density. Such samples can easily withstand a load of more than 160,000 times their own weight,” said Associate Professor Nick Fang. SourceAlso: See other Materials and Coatings tech briefs.

Posted in: Manufacturing & Prototyping, Rapid Prototyping & Tooling, Materials, Nanotechnology, News

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Thin Films Self-Assemble in One Minute

Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have devised a technique whereby self-assembling nanoparticle arrays can form a highly ordered thin film over macroscopic distances in one minute.

Posted in: Electronics & Computers, Electronic Components, Photonics, Optics, Manufacturing & Prototyping, Materials, Coatings & Adhesives, Composites, Nanotechnology, News

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New Way To Make Sheets Of Graphene Discovered

Graphene's promise as a material for new kinds of electronic devices, among other uses, has led researchers around the world to study the material in search of new applications. But one of the biggest limitations to wider use of the strong, lightweight, highly conductive material has been the hurdle of fabrication on an industrial scale.

Posted in: Electronics & Computers, Electronic Components, Materials, Coatings & Adhesives, Solar Power, Energy, Semiconductors & ICs, News

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Roof Tiles Clean the Air

A team of University of California, Riverside’s Bourns College of Engineering students has developed a titanium dioxide roof tile coating that removes up to 97 percent of smog-causing nitrogen oxides.The students' calculations show that 21 tons of nitrogen oxides would be eliminated daily if tiles on one million roofs were coated with their titanium dioxide mixture. The researchers coated two identical, off-the-shelf clay tiles with different amounts of titanium dioxide, a common compound found in everything from paint to food to cosmetics. The tiles were then placed inside a miniature atmospheric chamber that the students built out of wood, Teflon, and PVC piping.The chamber was connected to a source of nitrogen oxides and a device that reads concentrations of nitrogen oxides. The students used ultraviolet light to simulate sunlight, which activates the titanium dioxide and allows it to break down the nitrogen oxides. They found the titanium dioxide coated tiles removed between 88 percent and 97 percent of the nitrogen oxides.SourceAlso: Learn about Spectroscopic Determination of Trace Contaminants in High-Purity Oxygen.

Posted in: Remediation Technologies, Green Design & Manufacturing, Materials, Coatings & Adhesives, Test & Measurement, News

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Aircraft Wings Change Shape in Flight

The EU project SARISTU (Smart Intelligent Aircraft Structures) aims to reduce kerosene consumption by six percent, and integrating flexible landing devices into aircraft wings is one step towards that target. A new mechanism alters the landing flap’s shape to dynamically accommodate the airflow. Algorithms to control the required shape modifications in flight were programmed by the Fraunhofer Institute for Electronic Nano Systems ENAS in Chemnitz, in collaboration with colleagues from the Italian Aerospace Research Center (CIRA) and the University of Naples."We’ve come up with a silicon skin with alternate rigid and soft zones,” Said Andreas Lühring from Fraunhofer IFAM. “There are five hard and three soft zones, enclosed within a silicon skin cover extending over the top.”The mechanism sits underneath the soft zones, the areas that are most distended. While the novel design is noteworthy, it is the material itself that stands out, since the flexible parts are made of elastomeric foam that retains their elasticity even at temperatures ranging from -55 to 80° Celsius.Four 90-centimeter-long prototypes — two of which feature skin segments — are already undergoing testing.SourceAlso: Learn about Active Wing Shaping Control.

Posted in: Materials, Mechanical Components, Aerospace, Aviation, News

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