Materials & Coatings

Composite Silica Aerogels Opacified With Titania

Thermal insulation is enhanced by reducing the radiative contribution to heat transfer.A further improvement has been made to reduce the high-temperature thermal conductivities of the aerogel-matrix composite materials described in “Improved Silica Aerogel Composite Materials” (NPO-44287), NASA Tech Briefs, Vol. 32, No. 9 (September 2008), page 50. Because the contribution of infrared radiation to heat transfer increases sharply with temperature, the effective high-temperature thermal conductivity of a thermal-insulation material can be reduced by opacifying the material to reduce the radiative contribution. Therefore, the essence of the present improvement is to add an opacifying constituent material (specifically, TiO2 powder) to the aerogel-matrix composites.

Posted in: Briefs, TSP, Materials

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Multiplexed Colorimetric Solid-Phase Extraction

This analytical platform enables simultaneous determination of trace analytes in water.Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (CSPE) — an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In C-SPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a hand-held diffuse reflectance spectrophotometer. Im por - tant ly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes.

Posted in: Briefs, Materials

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Graphite Non-Wovens as Functional Layers in Diagnostic Test Kits

Blood-handling diagnostic test strips can be used for diabetes testing and monitoring, and testing for other diseases. The separation of serum or plasma from whole blood is of overriding importance in clinical chemistry. In particular, many diagnostic detection reactions of blood components proceed without impairment only after the red blood corpuscles have been separated off. This particularly applies to color reactions that are evaluated either by reflectometry or visually, or also electrochemically.

Posted in: Briefs, MDB, Briefs, Coatings & Adhesives, Materials, Bio-Medical, Medical, Patient Monitoring, Fluids and secretions, Medical equipment and supplies, Graphite, Test equipment and instrumentation

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Using Ozone To Clean and Passivate Oxygen-Handling Hardware

A proposed method of cleaning, passivating, and verifying the cleanliness of oxygen-handling hardware would extend the established art of cleaning by use of ozone. As used here, “cleaning” signifies ridding all exposed surfaces of combustible (in particular, carbon-based) contaminants. The method calls for exposing the surfaces of the hardware to ozone while monitoring the ozone effluent for carbon dioxide. The ozone would passivate the hardware while oxidizing carbon-based residues, converting the carbon in them to carbon dioxide. The exposure to ozone would be continued until no more carbon dioxide was detected, signifying that cleaning and passivation were complete.

Posted in: Briefs, Materials, Carbon dioxide, Oxygen equipment, Hardware

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Two-Piece Screens for Decontaminating Granular Material

These are more effective than are single-piece screens. Two-piece screens have been designed specifically for use in filtering a granular material to remove contaminant particles that are significantly wider or longer than are the desired granules. In the original application for which the two-piece screens were conceived, the granular material is ammonium perchlorate and the contaminant particles tend to be wires and other relatively long, rigid strands. The basic design of the two-piece screens can be adapted to other granular materials and contaminants by modifying critical dimensions to accommodate different grain and contaminant-particle sizes.

Posted in: Briefs, Materials, Product development, Materials properties, Particulate filters

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Metal Standards for Waveguide Characterization of Materials

Metal waveguide inserts can be tailored to have known scattering parameters. Rectangular-waveguide inserts that are made of non-ferromagnetic metals and are sized and shaped to function as notch filters have been conceived as reference standards for use in the rectangular- waveguide method of characterizing materials with respect to such constitutive electromagnetic properties as permittivity and permeability. Such standards are needed for determining the accuracy of measurements used in the method, as described below.

Posted in: Briefs, TSP, Materials, Waveguides, Conductivity, Materials properties, Metals, Test equipment and instrumentation, Test procedures

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Large-Format Carbon Nanotube Sheets Fabricated With Chemical Vapor Deposition

Non-woven, textile-like sheets of carbon nanotubes can be created without post-processing. Carbon nanotube (CNT) sheets, yarns, and their derivative products are beginning to emerge in the marketplace. A productive and scalable manufacturing method utilizes a chemical vapor deposition process for making very-large-format CNT non-woven, textile-like sheets directly from the reactor without post-processing.

Posted in: Briefs, Materials, Fabrication, Chemicals, Nanomaterials

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