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.

The j integral as a fracture criterion

Abstract: The path independent J integral, as formulated by Rice, can be viewed as a parameter which is an average measure of the crack tip elastic-plastic fied. This together with the fact that J can be evaluated experimentally, makes a critical J value an attractive elastic-plastic fracture criterion. The critical J value fracture criterion refers to crack initiation under plane strain conditions from essentially elastic to fully plastic behavior. Experiments supporting the validity of a critical J value fracture criterion are presented in this paper. Values of the J integral were determined experimentally for two steel alloys, one of low and the other of intermediate strength. A review is given of the analytical support for the critical J value fracture criterion. The range of applicability of the critical J value concept, its limitations, and its advantages are also discussed. /Author/

Electrical Insulation Deterioration Treated as a Chemical Rate Phenomenon

Abstract: The basis is presented for a more accurate interpretation of the results of physical type tests to measure the thermal aging of insulation together with a more accurate method of applying the results of such tests to predicting insulation deterioration in practice. Since the observed physical changes during thermal aging are the result of internal chemical changes in organic material, it is shown that the theory of chemical reaction rates can be applied to analyze experimental data on aging. The approximate 7 to 10 rule for the temperature coefficient of deterioration rate is replaced by a more accurate theoretical expression. Various examples of insulation life tests are analyzed using the graphical methods outlined in the paper. The chemical rate theory interpretation of thermal aging offers a more satisfactory method for extrapolating the results of limited aging tests of insulating materials so they can be applied to predicting amounts of thermal aging in high temperature cycles.

Momentum transfer cross sections for slow electrons in he, ar, kr, and xe from transport coefficients,

Abstract: Momentum-transfer cross sections for electrons in He, Ar, Kr, and Xe are obtained from a comparison of theoretical and experimental values of the drift velocities and of the ratio of the diffusion coefficient to the mobility coefficient for electrons in these gases. The theoretical transport coefficients are obtained by calculating accurate electron-energy distribution functions for energies below excitation using an assumed energy-dependent momentum-transfer cross section. The resulting theoretical values are compared with the available experimental data and adjustments made in the assumed cross sections until good agreement is obtained. The final momentum cross sections for helium is 5.0\ifmmode\pm\else\textpm\fi{}0.1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$ for an electron energy of 5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}3}$ eV and rises to 6.6\ifmmode\pm\else\textpm\fi{}0.3\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$ for energies near 1 eV. The cross sections obtained for Ar, Kr, and Xe decrease from 6\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}16}$, 2.6\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}15}$, and ${10}^{\ensuremath{-}14}$ ${\mathrm{cm}}^{2}$, respectively, at 0.01 eV to minimum values of 1.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ ${\mathrm{cm}}^{2}$ at 0.3 eV for Ar, 5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ ${\mathrm{cm}}^{2}$ at 0.65 eV for Kr, and 1.2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$ at 0.6 eV for Xe. The agreement of the very-low-energy results with the effective-range theory of electron scattering is good.

Image Restoration by the Method of Least Squares

Abstract: The restoration of optical images, as well as the unfolding of spectroscopic and other data that have been convolved with a window function or an instrumental impulse response, can be viewed as the solution of an integral equation. Solution of such an integral equation when the data are corrupted by noise or experimental error is treated as the problem of finding an estimate that is a linear functional of the data and minimizes the mean squared error between the true solution and itself. The estimate depends on assumptions about the spectral densities of the images and the noise, the choice of which is discussed. Coherent optical processing and digital processing are described.

Effect of stress-induced phase transformation on the properties of polycrystalline zirconia containing metastable tetragonal phase

Abstract: Polycrystalline zirconia containing a high content of metastable tetragonal phase shows high strength (∼ 700 MPa), high fracture toughness (Kc = 6 to 9 MN m−3/2) and small grain size (<0.3jμm). The strength and grain size remain nearly constant over a wide range of tetragonal phase content (100 to 30%). At a low concentration of tetragonal phase <30%, there is a rapid decrease in strength accompanied by a rapid increase in grain size. These results are explained by means of a stress-induced phase transformation in the metastable tetragonal phase.