Materials & Coatings

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

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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

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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

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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

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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

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Filtering Water by Use of Ultrasonically Vibrated Nanotubes

Water molecules could flow through; larger molecules and other particles could not. Devices that could be characterized as acoustically driven molecular sieves have been proposed for filtering water to remove all biological contaminants and all molecules larger than water molecules. Originally intended for purifying wastewater for reuse aboard spacecraft, these devices could also be attractive for use on Earth in numerous settings in which there are requirements to obtain potable, medical-grade, or otherwise pure water from contaminated water supplies. These devices could also serve as efficient means of removing some or all water from chemical products — for example, they might be useful as adjuncts or substitutes for stills in the removal of water from alcohols and alcoholic beverages. These devices may be constructed using various materials, such as ceramics, metallics, or polymers, depending on end-use requirements.

Posted in: Briefs, Materials

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Improvements in Production of Single-Walled Carbon Nanotubes

Continuous mass production in fluidized-bed reactors now appears feasible. A continuing program of research and development has been directed toward improvement of a prior batch process in which single-walled carbon nanotubes are formed by catalytic disproportionation of carbon monoxide in a fluidized-bed reactor. The overall effect of the improvements has been to make progress toward converting the process from a batch mode to a continuous mode and to scaling of production to larger quantities. Efforts have also been made to optimize associated purification and dispersion post processes to make them effective at large scales and to investigate means of incorporating the purified products into composite materials. The ultimate purpose of the program is to enable the production of high-quality single-walled carbon nanotubes in quantities large enough and at costs low enough to foster the further development of practical applications.

Posted in: Briefs, Materials

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