Westinghouse Electric

About: Westinghouse Electric is a company organization based out in Cranberry Township, Pennsylvania, United States. It is known for research contribution in the topics: Brake & Signal. The organization has 27959 authors who have published 38036 publications receiving 523387 citations.

Elastic and Inelastic Collision Cross Sections in Hydrogen and Deuterium from Transport Coefficients

Abstract: By means of a numerical solution of the Boltzmann equation, elastic and inelastic collision cross sections have been derived for electrons in ${\mathrm{H}}_{2}$ and ${\mathrm{D}}_{2}$ subjected to a dc electric field. The cross sections for momentum transfer, rotational excitation, vibrational excitation, electronic excitation, and ionization are investigated by comparing experimental and theoretical values of transport coefficient. The same momentum transfer cross section previously obtained for ${\mathrm{H}}_{2}$ by Frost and Phelps has been found to be valid for ${\mathrm{D}}_{2}$. Good agreement is secured between experiment and theory by multiplying the theoretical rotational cross sections of Gerjuoy and Stein by approximately 1.5, provided the polarization factor of Dalgarno and Moffett is used. The final cross section for vibrational excitation of ${\mathrm{H}}_{2}$ has a threshold at 0.52 eV and a peak of 7.7\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ ${\mathrm{cm}}^{2}$ at 4.5 eV, whereas that of ${\mathrm{D}}_{2}$ has a threshold at 0.36 eV and a peak of 6.6\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ ${\mathrm{cm}}^{2}$ at 4.7 eV. The derived electronic excitation cross sections are the same for both ${\mathrm{H}}_{2}$ and ${\mathrm{D}}_{2}$. The ionization cross section was taken from the experimental results of Tate and Smith. Calculated transport coefficients for electrons subjected to crossed electric and magnetic fields, and high-frequency ac electric fields are in agreement with recent experimental and theoretical results.

The high-temperature oxidation, reduction, and volatilization reactions of silicon and silicon carbide

Abstract: A thermochemical analysis was made of the oxidation, reduction, and volatilization reactions which occur in the Si-O-C system. One characteristic feature is the high SiO(g) and SiO(g) + CO(g) pressures at the Si(s)-SiO2 and SiC(s)-SiO2(s) interfaces. Active oxidation with weight losses and passive oxidation with weight gains were found on oxidizing Si(s) and SiC(s) in low oxygen pressures above 1000°C. Rapid oxidation was related to the SiO(g) and SiO(g) + C0(g) pressures at the Si(s) or SiC(s)-SiO2(s) interfaces.

Optical Properties of Cubic SiC: Luminescence of Nitrogen-Exciton Complexes, and Interband Absorption

Abstract: Absorption measurements of cubic SiC at 4.2\ifmmode^\circ\else\textdegree\fi{}K show that the absorption edge is due to indirect, exciton-creating transitions, with an exciton energy gap of 2.390 eV. The energies of the phonons participating in these transitions are 46, 79, 94, and 103 meV, and suggest that the conduction-band minima are at $X$, as predicted by recent calculations. The phonon energies are accurately determined from the 6\ifmmode^\circ\else\textdegree\fi{}K luminescence spectrum of four-particle nitrogen-exciton complexes. Additional lines in the luminescence spectrum at higher temperatures are attributed to thermally excited states of of the complex. Comparisons of cubic SiC with other polytypes are given. There is close agreement in some phonon energies, but energy gaps are very different. An empirical correlation of the energy gaps with percent "hexagonal" is given for seven polytypes.

Transient modeling and simulation of a tubular solid oxide fuel cell

Abstract: This paper describes the development of a computer model for simulating the transient operation of a tubular solid oxide fuel cell (SOFC). The model includes the electrochemical, thermal, and mass flow elements that affect SOFC electrical output. The electrochemical and thermal parts of the model were developed and verified separately before they were combined to form the transient model. The results of model verification tests are presented. Transient simulations were conducted with constant reactant flows and constant inlet temperatures. The transient electrical response of the cell to a load change is described.