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Hydrazine Absorbent/Detoxification Pad

This hydrazine-degrading pad has applications in hazardous-material emergency response situations. Lyndon B. Johnson Space Center, Houston, Texas A new chemistry was developed for existing hydrazine absorbent/detoxification pads. Enhancements include faster reaction rates, weight reduction, a color change that indicates spill occurrence, and another color change that indicates successful hydrazine degradation. The previous spill control pad, using copper oxide on the silica gel substrate as the reactant, affected only 50 percent degradation of hydrazine after 9 hours. The new prototypes have been found to degrade hydrazine from 95 to 99.9 percent in only 5 minutes, and to below detection limits within 90 minutes.

Posted in: Materials, Briefs, TSP

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Nanotechnology Approach to Lightweight, Multifunctional Polyethylene Composite Materials

Potential uses include personal armor, implantable prosthetics, and cut-resistant fabrics such as gloves worn by chefs and scuba divers. Langley Research Center, Hampton, Virginia Of several ideas being pursued by NASA for the reduction of radiation dosage to astronauts, the use of ultra-high-molecular-weight polyethylene (UHMWPE)-based composite materials for both radiation shielding and micrometeorite shielding appears to be particularly appealing. UHMWPE has long been understood to provide superior radiation shielding following encounters with energetic nucleons due to its high hydrogen content. Meanwhile, impacts of micrometeorites with UHMWPE tend to vaporize it, rather than causing spallation of the shield material, which then creates additional potentially damaging micrometeorites. Less widely appreciated is the high specific strength of UHMWPE and UHMWPE fibers, which provide structural integrity to the composite. Amongst thermoplastics, UHMWPE has the highest impact strength and is also highly resistant to abrasion. Despite this highly appealing combination of properties, UHMWPE’s key mechanical properties can be improved by forming composites with other nanostructured materials, leading to further performance increases and weight reductions. Such composites will increase the ability of UHMWPE structures to withstand micrometeorite impacts and maintain the structural integrity of a pressurized environment.

Posted in: Materials, Briefs, TSP

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Electrostrictive Polymers

These lightweight and durable materials enable sensing and actuation devices. Langley Research Center, Hampton, Virginia A new class of electroactive polymeric blend materials has been created that offers both sensing and actuation dual functionality. The blend is comprised of two components where one has sensing capability, and the other has actuating capability. These innovative materials provide significant field-induced strain, high mechanical output force, and exceptional strain energy density. These electrostrictive polymers are conformable, lightweight, and durable. The processing system to fabricate these polymers is simple and can be manipulated to control and optimize the materials’ mechanical and electrical properties.

Posted in: Materials, Briefs, TSP

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Elevated-Temperature, Highly Emissive Coating for Energy Dissipation of Large Surfaces

This coating can be used in high-temperature rocket nozzles, control surfaces, industrial furnaces, and transfer lines. Marshall Space Flight Center, Alabama This coating demonstrates high emittance above 80% or better at broad wavelengths within the infrared spectrum. It has shown to have an extremely stable emittance at lower wavelengths within the infrared (IR) spectrum, where energy dissipation is critical at elevated temperatures. The coating has demonstrated increases in surface texturing, and ultimately an increase in emissivity when exposed to temperatures up to 2,050 °F (≈1,120 °C). It is also stable at continuous run, elevated temperatures, and shows no signs of spalling or erosion.

Posted in: Materials, Coatings & Adhesives, Briefs

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Catalyst for Treatment and Control of Post-Combustion Emissions

This oxidation/reduction catalyst can be used in diesel and natural gas applications, and in nonautomotive pollution sources. Langley Research Center, Hampton, Virginia Emissions from fossil-fuel combustion contribute significantly to smog, acid rain, and global warming problems, and are subject to stringent environmental regulations. These regulations are expected to become more stringent as state and regional authorities become more involved in addressing these environmental problems. Better systems are needed for catalytic control.

Posted in: Materials, Coatings & Adhesives, Briefs, TSP

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Thermally Activated Crack Healing Mechanism for Metallic Materials

A thin metallic film of a low-melting-temperature healing agent is used. Langley Research Center, Hampton, Virginia A thermally activated healing mechanism is proposed and experimentally validated to mitigate crack propagation damage in metallic materials. The protected structure is coated with a thin metallic film of a low-melting-temperature healing agent. To heal or mitigate crack damage, the structure is heated to the melting temperature of the healing agent, allowing it to flow into the crack opening. Once in the crack mouth, the healing agent has two benefits: (1) by adhering to the crack surfaces, the healing agent bridges the crack, reducing the amount of load at the crack tip; and (2) any voluminous substance in the crack mouth causes crack closure (premature crack-face contact during cyclic loading) that also reduces the crack-tip loading.

Posted in: Materials, Coatings & Adhesives, Briefs, TSP

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Subsurface Imaging of Nanocomposites

Applications include sensors and actuators, aerospace structures, and tissue infusion in medical areas. Langley Research Center, Hampton, Virginia A nondestructive method that is based on modified atomic force ultrasonic microscopy (AFUM) methods has been developed for characterizing nanomaterials. The technology allows imaging and quantifying of material properties at the surface and subsurface levels. The technology reveals the orientation of nanotubes within a composite structure and offers the ability to determine subsurface characteristics without destroying the nanomaterial structure. The method is widely applicable for basic nanomaterials characterization, including distribution and orientation of particles in a nanocomposite, localized elastic constants and changes in elastic constants, adhesive surface properties, sound velocity, and material damping coefficient.

Posted in: Materials, Coatings & Adhesives, Briefs

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