Physical Sciences

Gauges for Highly Precise Metrology of a Compound Mirror

High precision is achieved through careful attention to details of complex designs. Three optical gauges have been developed for guiding the assembly and measuring precisely the reflecting surfaces of a compound mirror that comprises a corner-cube retroreflector glued in a hole on a flat mirror. In the specific application for which the gauges were developed, the compound mirror is part of a siderostat in a stellar interferometer. The flat-mirror portion of the compound mirror is the siderostat mirror; the retroreflector portion of the compound mirror is to be used, during operation of the interferometer, to monitor the location of the siderostat mirror surface relative to other optical surfaces of the interferometer. Nominally, the optical corner of the retroreflector should lie precisely on the siderostat mirror surface, but this precision cannot be achieved in fabrication: in practice, there remains some distance between the optical corner and the siderostat mirror surface. For proper operation of the interferometer, it is required to make this distance as small as possible and to know this distance within 1 nm. The three gauges make it possible to satisfy these requirements.

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Improved Electrolytic Hydrogen Peroxide Generator

Energy efficiency exceeds that of a prior electrolytic H2O2 generator. An improved apparatus for the electrolytic generation of hydrogen peroxide dissolved in water has been developed. The apparatus is a prototype of H2O2 generators for the safe and effective sterilization of water, sterilization of equipment in contact with water, and other applications in which there is need for hydrogen peroxide at low concentration as an oxidant. Potential applications for electrolytic H2O2 generators include purification of water for drinking and for use in industrial processes, sanitation for hospitals and biotechnological industries, inhibition and removal of biofouling in heat exchangers, cooling towers, filtration units, and the treatment of wastewater by use of advanced oxidation processes that are promoted by H2O2. The apparatus is an electrochemical cell in which the electrodes are located on opposite sides of a commercially available polymeric membrane, which separates the electrolytes of the two electrolytic half-reactions.

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Modified Penning-Malmberg Trap for Storing Antiprotons

One set of electrodes is used for both transmission and reception.

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Tumbleweed Rovers

Lightweight balls containing scientific instruments are propelled across terrain by wind.

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Simulations of Evaporating Multicomponent Fuel Drops

A paper presents additional information on the subject matter of “Model of Mixing Layer With Multicomponent Evaporating Drops” (NPO-30505), NASA Tech Briefs, Vol. 28, No. 3 (March 2004), page 55.

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Instrumentation for Sensitive Gas Measurements

Measurements are based on cavity-enhanced absorption.

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Apparatus for Testing Flat Specimens of Thermal Insulation

An improved design affords flexibility for testing under diverse conditions.

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