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Microfabricated Segmented-Involute-Foil Regenerator for Stirling Engines

Tests show significantly improved performance.An involute-foil regenerator was designed, microfabricated, and tested in an oscillating-flow test rig. The concept consists of stacked involute-foil nickel disks (see figure) microfabricated via a lithographic process. Test results yielded a performance of about twice that of the 90-percent random-fiber currently used in small Stirling converters.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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Reducing Seal Adhesion in Low Impact Docking Systems

Atomic oxygen is used to treat mating silica surfaces to reduce unwanted adhesion during docking/undocking operations.Silicone elastomers, used in seals for airlocks or other sealing surfaces in space, are sticky in their as-received condition. Because of the sticking, a greater force may be needed to separate the mating surfaces. If the adhesion is sufficiently high, a sudden unpredicted movement of the spacecraft during undocking, vibration, or uneven release could pull off the seal, resulting in a damage that would have to be repaired before another docking. The damaged seal can result in significant gas leakage and possibly in a catastrophic mishap impacting the safety of the crew. It is also possible that a compromised seal could result in a delayed but sudden gas leak that could put the crew at unexpected risk. This is especially of concern for androgynous seals, which have identical mating surfaces on both sides for interchangeability and redundancy. Such seals typically have elastomer-on-elastomer sealing surfaces. To reduce sticking, one could use release agents such as powders and lubricants, but these can be easily removed and transferred to other surfaces, causing uneven sealing and contamination. Modification of the elastomer surface to make a more slippery and less sticky surface that is integral with the bulk elastomer would be more desirable.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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Corrosion-Resistant Container for Molten-Material Processing

A combination of materials functions and survives in hot, corrosive environments.In a carbothermal process, gaseous methane is passed over molten regolith, which is heated past its melting point to a temperature in excess of 1,625 °C. At this temperature, materials in contact with the molten regolith (or regolith simulant) corrode and lose their structural properties. As a result, fabricating a crucible to hold the molten material and providing a method of contact heating have been problematic.

Posted in: Manufacturing & Prototyping, Briefs

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Process To Produce Iron Nanoparticle Lunar Dust Simulant Composite

A document discusses a method for producing nanophase iron lunar dust composite simulant by heating a mixture of carbon black and current lunar simulant types (mixed oxide including iron oxide) at a high temperature to reduce ionic iron into elemental iron. The product is a chemically modified lunar simulant that can be attracted by a magnet, and has a surface layer with an iron concentration that is increased during the reaction. The iron was found to be α-iron and Fe3O4 nanoparticles. The simulant produced with this method contains iron nanoparticles not available previously, and they are stable in ambient air. These nanoparticles can be mass-produced simply.

Posted in: Manufacturing & Prototyping, Briefs, TSP

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Repeatable, Low-Cost UV Assembly of Biosensors

UV spot curing system ensures greater accuracy for automated and manual manufacturing of biosensors.A biosensor is an analytical device that converts a biological response into an electrical signal. It is increasingly being used as a cost-effective diagnostic tool that offers the capability to render efficient, easy-to-use, and accurate diagnosis. While technological advances in biosensors are allowing this technology to cater to an extensive range of applications in a number of fields, such as industrial and environmental testing, the largest applications have been in the healthcare sector, including glucose detection, pregnancy testing, blood testing, breath analyzers, and cancer diagnosis.

Posted in: Bio-Medical, Briefs, Briefs, Coatings & Adhesives, Patient Monitoring, Sensors

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Electrochemical Hydrogen Peroxide Generator

Stable electrocatalysts can produce hydrogen peroxide under acidic conditions.Two-electron reduction of oxygen to produce hydrogen peroxide is a much researched topic. Most of the work has been done in the production of hydrogen peroxide in basic media, in order to address the needs of the pulp and paper industry. However, peroxides under alkaline conditions show poor stabilities and are not useful in disinfection applications. There is a need to design electrocatalysts that are stable and provide good current and energy efficiencies to produce hydrogen peroxide under acidic conditions.

Posted in: Manufacturing & Prototyping, Briefs

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Fabrication of Single, Vertically Aligned Carbon Nanotubes in 3D Nanoscale Architectures

Potential applications of this process are integrated circuits, nano switches, and biological sensors.Plasma-enhanced chemical vapor deposition (PECVD) and high-throughput manufacturing techniques for integrating single, aligned carbon nanotubes (CNTs) into novel 3D nanoscale architectures have been developed. First, the PECVD growth technique ensures excellent alignment of the tubes, since the tubes align in the direction of the electric field in the plasma as they are growing. Second, the tubes generated with this technique are all metallic, so their chirality is predetermined, which is important for electronic applications. Third, a wafer-scale manufacturing process was developed that is high-throughput and low-cost, and yet enables the integration of just single, aligned tubes with nanoscale 3D architectures with unprecedented placement accuracy and does not rely on e-beam lithography. Such techniques should lend themselves to the integration of PECVD-grown tubes for applications ranging from interconnects, nanoelectromechanical systems (NEMS), sensors, bioprobes, or other 3D electronic devices.

Posted in: Manufacturing & Prototyping, Briefs

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