George M. Wood

Publications (5)0 Total impact

• Article: Instrumentation for measurement of gas permeability of polymeric membranes

  Billy T. Upchurch, George M. Wood, Kenneth G. Brown, Karen S. Burns
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  ABSTRACT: A mass spectrometric 'Dynamic Delta' method for the measurement of gas permeability of polymeric membranes has been developed. The method is universally applicable for measurement of the permeability of any gas through polymeric membrane materials. The usual large sample size of more than 100 square centimeters required for other methods is not necessary for this new method which requires a size less than one square centimeter. The new method should fulfill requirements and find applicability for industrial materials such as food packaging, contact lenses and other commercial materials where gas permeability or permselectivity properties are important.
  03/1993;
• Article: Pt/SnO2-based CO-oxidation catalysts for long-life closed-cycle CO2 lasers

  David R. Schryer, Billy T. Upchurch, Robert V. Hess, George M. Wood, Barry D. Sidney, Irvin M. Miller, Kenneth G. Brown, John D. Vannorman, Jacqueline Schryer, David R. Brown
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  ABSTRACT: Noble-metal/tin-oxide based catalysts such as Pt/SnO2 have been shown to be good catalysts for the efficient oxidation of CO at or near room temperature. These catalysts require a reductive pretreatment and traces of hydrogen or water to exhibit their full activity. Addition of Palladium enhances the activity of these catalysts with about 15 to 20 percent Pt, 4 percent Pd, and the balance SnO2 being an optimum composition. Unfortunately, these catalysts presently exhibit significant decay due in part to CO2 retention, probably as a bicarbonate. Research on minimizing the decay in activity of these catalysts is currently in progress. A proposed mechanism of CO oxidation on Pt/SnO2-based catalysts has been developed and is discussed.
  Low-Temperature CO-Oxidation Catalysts for Long-Life CO2 Lasers. 05/1990; -1:41-53.
• Article: Isotope exchange in oxide-containing catalyst

  Kenneth G. Brown, Billy T. Upchurch, Robert V. Hess, Irvin M. Miller, David R. Schryer, Barry D. Sidney, George M. Wood, Ronald F. Hoyt
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  ABSTRACT: A method of exchanging rare-isotope oxygen for common-isotope oxygen in the top several layers of an oxide-containing catalyst is disclosed. A sample of an oxide-containing catalyst is exposed to a flowing stream of reducing gas in an inert carrier gas at a temperature suitable for the removal of the reactive common-isotope oxygen atoms from the surface layer or layers of the catalyst without damaging the catalyst structure. The reduction temperature must be higher than any at which the catalyst will subsequently operate. Sufficient reducing gas is used to allow removal of all the reactive common-isotope oxygen atoms in the top several layers of the catalyst. The catalyst is then reoxidized with the desired rare-isotope oxygen in sufficient quantity to replace all of the common-isotope oxygen that was removed.
  07/1989;
• Article: Development of CO oxidation catalysts for the Laser Atmospheric Wind Sounder (LAWS)

  Billy T. Upchurch, David R. Schryer, George M. Wood, Robert V. Hess
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  ABSTRACT: Available commercial catalysts have been studied both in a laser and under simulated closed-cycle laser conditions. The results demonstrate that long-term decay of catalytic efficiency persists in currently available catalysts. In one recently developed catalyst, however, the decay in efficiency is significantly lower than in previously available catalysts while the catalyst operates quite well under ambient temperature conditions. Synthesis and mechanistic details in the development of the new catalyst composition are discussed.
  02/1989;
• Article: Research on catalysts for long-life closed-cycle CO2 laser oaperation

  Barry D. Sidney, David R. Schryer, Billy T. Upchurch, Robert V. Hess, George M. Wood
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  ABSTRACT: Long-life, closed-cycle operation of pulsed CO2 lasers requires catalytic CO-O2 recombination both to remove O2, which is formed by discharge-induced CO2 decomposition, and to regenerate CO2. Platinum metal on a tin-oxide substrate (Pt/SnO2) has been found to be an effective catalyst for such recombination in the desired temperature range of 25 to 100 C. This paper presents a description of ongoing research at NASA-Langley on Pt/SnO2 catalyzed CO-O2 recombination. Included are studies with rare-isotope gases since rare-isotope CO2 is desirable as a laser gas for enhanced atmospheric transmission. Results presented include: (1) the effects of various catalyst pretreatment techniques on catalyst efficiency; (2) development of a technique, verified in a 30-hour test, to prevent isotopic scrambling when C(O-18) and (O-18)2 are reacted in the presence of a common-isotope Pt/Sn(O-16)2 catalyst; and (3) development of a mathematical model of a laser discharge prior to catalyst introduction.
  02/1987;