Materials

Blocking Filters With Enhanced Throughput for X-Ray Microcalorimetry

Polyimide replaces the standard metal mesh. New and improved blocking filters (see figure) have been developed for microcalorimeters on several mission payloads, made of high-transmission polyimide support mesh, that can replace the nickel mesh used in previous blocking filter flight designs. To realize the resolution and signal sensitivity of today’s x-ray microcalorimeters, significant improvements in the blocking filter stack are needed.

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High-Thermal-Conductivity Fabrics

Applications include cooling garments for firefighters, hazmat personnel, soldiers, and in cooling vests for multiple sclerosis patients. Heat management with common textiles such as nylon and spandex is hindered by the poor thermal conductivity from the skin surface to cooling surfaces. This innovation showed marked improvement in thermal conductivity of the individual fibers and tubing, as well as components assembled from them.

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Electrospun Nanofiber Coating of Fiber Materials: A Composite Toughening Approach

Companies could apply this technology in producing fabric products for use in composite manufacturing. Textile-based composites could significantly benefit from local toughening using nanofiber coatings. Nanofibers, thermoplastic or otherwise, can be applied to the surface of the fiber tow bundle, achieving toughening of the fiber tow contact surfaces, resulting in tougher and more damage-resistant/tolerant composite structures. The same technique could also be applied to other technologies such as tape laying, fiber placement, or filament winding operations. Other modifications to the composite properties such as thermal and electrical conductivity could be made through selection of appropriate nanofiber material.

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Solar Nanowire Template Permits Flexible Energy Absorption

Researchers creating electricity through photovoltaics want to convert as many of the sun’s wavelengths as possible to achieve maximum efficiency. For this reason, they see indium gallium nitride as a valuable future material for photovoltaic systems. Changing the concentration of indium allows researchers to tune the material’s response so it collects solar energy from a variety of wavelengths.

Posted in: Materials, Solar Power, Energy Efficiency, Renewable Energy, Nanotechnology, News

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Nanoengineered Thermal Materials Based on Carbon Nanotube Array Composites

Thermal conductors for integrated circuits and devices can be made from carbon nanotube arrays. State-of-the-art integrated circuits (ICs) for microprocessors routinely dissipate power densities on the order of 50 W/cm2. This large power is due to the localized heating of ICs operating at high frequencies and must be managed for future highfrequency microelectronic applications. As the size of components and devices for ICs and other appliances becomes smaller, it becomes more difficult to provide heat dissipation and transport for such components and devices. A thermal conductor for a macro-sized thermal conductor is generally inadequate for use with a micro-sized component or device, in part due to scaling problems.

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Polyimide Aerogel Thin Films

Polyimide aerogels have been cross-linked through multifunctional amines. This invention builds on “Polyimide Aerogels With Three-Dimensional Cross-Linked Structure,” (LEW-18486-1), NASA Tech Briefs, Vol. 34, No. 8 (August 2010), page 38, and may be considered as a continuation of that invention, which results in a polyimide aerogel with a flexible, formable form.

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Composite Laminate With Coefficient of Thermal Expansion Matching D263 Glass

The laminate is a combination of carbon fiber with fiberglass. The International X-ray Observatory project seeks to make an X-ray telescope assembly with 14,000 flexible glass segments. The glass used is commercially available SCHOTT D263 glass. Thermal expansion causes the mirror to distort out of alignment. A housing material is needed that has a matching coefficient of thermal expansion (CTE) so that when temperatures change in the X-ray mirror assembly, the glass and housing pieces expand equally, thus reducing or eliminating distortion. Desirable characteristics of this material include a high stiffness/ weight ratio, and low density.

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