Materials

Transformers: Shape-Changing Space Systems Built With Robotic Textiles

These easy-to-fabricate textiles can be used in robotics and smart habitats/shelters. Prior approaches to transformer-like robots had only very limited success. They suffer from lack of reliability, ability to integrate large surfaces, and very modest change in overall shape. Robots can now be built from two-dimensional (2D) layers of robotic fabric. This expands on ideas of electronic fabrics for electronic textiles, and incorporates sensors, actuators, power, and communications. The 2D solution is easier/cheaper to fabricate, packs more compactly, and ensures a wider range of shape change than 3D modules.

Posted in: Materials, Briefs

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Adjusting Permittivity by Blending Varying Ratios of SWNTs

High, intermediate, and low permittivity values can be tailored for specific applications. A new composite material of singlewalled carbon nanotubes (SWNTs) displays radio frequency (0 to 1 GHz) permittivity properties that can be adjusted based upon the nanotube composition. When varying ratios of raw to functionalized SWNTs are blended into the silicone elastomer matrix at a total loading of 0.5 percent by weight, a target real permittivity value can be obtained between 70 and 3. This has particular use for designing materials for microwave lenses, microstrips, filters, resonators, high-strength/low-weight electromagnetic interference (EMI) shielding, antennas, waveguides, and low-loss magneto-dielectric products for applications like radome construction.

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Polyolefin-Based Aerogels

These aerogels can be used for thermal insulation and radiation shielding in apparel, aircraft, race car insulation, and military and recreation tents. An organic polybutadiene (PB) rubber-based aerogel insulation material was developed that will provide superior thermal insulation and inherent radiation protection, exhibiting the flexibility, resiliency, toughness, and durability typical of the parent polymer, yet with the low density and superior insulation properties associated with the aerogels. The rubbery behaviors of the PB rubber-based aerogels are able to overcome the weak and brittle nature of conventional inorganic and organic aerogel insulation materials. Additionally, with higher content of hydrogen in their structure, the PB rubber aerogels will also provide inherently better radiation protection than those of inorganic and carbon aerogels. Since PB rubber aerogels also exhibit good hydrophobicity due to their hydrocarbon molecular structure, they will provide better performance reliability and durability as well as simpler, more economic, and environmentally friendly production over the conventional silica or other inorganic-based aerogels, which require chemical treatment to make them hydrophobic.

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An Integrated, Layered-Spinel Composite Cathode for Energy Storage Applications

The composite cathode can be used in rechargeable Li-ion batteries in hybrid electric vehicles, laptops, medical devices, and military vehicles. At low operating temperatures, commercially available electrode materials for lithium-ion batteries do not fully meet the energy and power requirements for NASA’s exploration activities. The composite cathode under development is projected to provide the required energy and power densities at low temperatures and its usage will considerably reduce the overall volume and weight of the battery pack.

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Engineered Multifunctional Surfaces for Fluid Handling

These processes create antibacterial and hydrophilic properties on metallic and polymeric surfaces. Designs incorporating variations in capillary geometry and hydrophilic and/or antibacterial surface properties have been developed that are capable of passive gas/liquid separation and passive water flow. These designs can incorporate capillary grooves and/or surfaces arranged to create linear and circumferential capillary geometry at the micro and macro scale, radial fin configurations, micro holes and patterns, and combinations of the above.

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Can Cobalt-Graphene Beat Out Platinum As Catalyst in Hydrogen Fuel Cells?

Platinum works well as a catalyst in hydrogen fuel cells, but it is expensive and degrades over time. Brown University chemist Shouheng Sun and his students have developed a new material — a graphene sheet covered by cobalt and cobalt-oxide nanoparticles — that can catalyze the oxygen reduction reaction nearly as well as platinum does and is substantially more durable.

Posted in: Alternative Fuels, Materials, Energy, News

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'Nanoflowers' for Energy Storage and Solar Cells

North Carolina State University researchers have created flower-like structures out of germanium sulfide (GeS) – a semiconductor material – that have extremely thin petals with an enormous surface area. The GeS flowers hold promise for next-generation energy storage devices and solar cells.

Posted in: Batteries, Materials, Energy Storage, Solar Power, Renewable Energy, Nanotechnology, News

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