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Articles 91 - 95 of 95

Full-Text Articles in Chemistry

A Diamond Thin Film Flow Sensor, Sacharia Albin, John C. Hagwood, John B. Cooper, David L. Gray, Scott D. Martinson, Michael A. Scott Jan 1995

A Diamond Thin Film Flow Sensor, Sacharia Albin, John C. Hagwood, John B. Cooper, David L. Gray, Scott D. Martinson, Michael A. Scott

Electrical & Computer Engineering Faculty Publications

We present the results of theoretical modeling and experimental testing of a diamond thin film sensor for flow studies. It is shown that the high thermal conductivity of a diamond film can enhance the frequency response of the flow sensor. One-dimensional heat diffusion equation was solved using the finite difference method for determining the frequency response. Two different sensor structures were analyzed: a Ni film on a quartz substrate (Ni/Q) and an intermediate layer of diamond film between the Ni film and quartz substrate (Ni/D/Q). The theoretical model predicts a frequency response for the Ni/D/Q sensor higher than that of …


Thermal Characterization Of Carbon Monoxide Oxidation Catalysts Using Thermogravimetric Analysts And Differential Scanning Calorimetry, Rene A. Bartgis Oct 1991

Thermal Characterization Of Carbon Monoxide Oxidation Catalysts Using Thermogravimetric Analysts And Differential Scanning Calorimetry, Rene A. Bartgis

Chemistry & Biochemistry Theses & Dissertations

Catalysts composed of platinum and/or palladium on tin (IV) oxide supports, with and without silica gel, as well as catalysts composed of gold on manganese oxide, have been developed for the recombination of carbon monoxide and oxygen to form carbon dioxide for use in carbon dioxide lasers. A thermogravimetric method and a differential scanning calorimetric method have been developed for the thermal characterization of these catalysts. The mass loss data and the enthalpy changes determined as the catalysts lost water were then related to existing activity data for these catalysts. No relationship was found between the thermal data and the …


Second Coefficient Of Viscosity In Air, Robert L. Ash, Allan J. Zuckerwar, Zhonquan Zheng Jan 1991

Second Coefficient Of Viscosity In Air, Robert L. Ash, Allan J. Zuckerwar, Zhonquan Zheng

Mechanical & Aerospace Engineering Faculty Publications

Acoustic attenuation measurements in air were analyzed in order to estimate the second coefficient of viscosity. Data over a temperature range of 11 C to 50 C and at relative humidities between 6 percent and 91 percent were used. This analysis showed that the second coefficient of viscosity varied between 1900 and 20,000 times larger than the dynamic or first coefficient of viscosity over the temperature and humidity range of the data. In addition, the data showed that the molecular relaxation effects, which are responsible for the magnitude of the second coefficient of viscosity, place severe limits on the use …


Luminescence In Slipped And Dislocation-Free Laser-Annealed Silicon, R.H. Uebbing, P. Wagner, H. Baumgart, H. J. Queisser Jan 1980

Luminescence In Slipped And Dislocation-Free Laser-Annealed Silicon, R.H. Uebbing, P. Wagner, H. Baumgart, H. J. Queisser

Electrical & Computer Engineering Faculty Publications

Photoluminescence of cw laser-annealed silicon shows a dramatic difference in electronic behavior of the reconstructed material depending upon either creation or suppression of dislocations. Beyond a critical exposure time slip appears, and the luminescence of these samples is dominated by dislocation-related defect levels.


The Synthesis Of New Maleimide Addition Polymer Precursors, Richard B. Brown Jul 1975

The Synthesis Of New Maleimide Addition Polymer Precursors, Richard B. Brown

Chemistry & Biochemistry Theses & Dissertations

1H-2,3-dimethylpyrrolo(1,2-a) benzimidazol-l-one (27) and 1H,9H- 2,3,7,8-tetramethyl-bispyrrolo(1,2-a:6,7-a')benzodiimidazo1-1,9-dione (32) have been synthesized from dimethylmaleic anhydride and o-phenylenediamine and 1,2,4,5-tetraaminobenzene, respectively. The presence of reactive olefinic double bonds in the synthesized compounds was of interest as a site for possible addition polymerization.

The synthetic route involved, in both cases, a simple nucleophilic substitution reaction between the diamine(or tetraamine) and the anhydride to form an intermediate amide-acid-amine which rapidly cyclized to the imide amine. The final ring closure required more rigorous conditions and occurred at melt reaction temperatures.