Showing papers by "Westinghouse Electric published in 1978"

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.

Review and extension of compliance information for common crack growth specimens

Abstract: Elastic compliance expressions for compact type (CT) and WOL specimens have been formulated for a wide range of crack lengths (0.2 ⩽a/W ⩽ 0.975) using results from Newman's modified boundary collection techniques and Wilson's deep crack analysis. The location of the axis of rotation of the specimen arms at various crack lengths has been calculated and subsequently used in a proposed extrapolation technique to predict compliance at any location of the specimen convenient for measuring deflection during a crack growth test. The predicted compliances were found to be in excellent agreement with expreimental values for the two specimen types considered. Compliance expressions are also included for the center crack tension specimen.

Principles and Applications of Static, Thyristor-Controlled Shunt Compensators

Abstract: In recent years, there has been a rapid increase in the number of thyristor-controlled shunt compensators used in industrial and utility systems for dynamic power factor correction and terminal voltage stabilization. These thyristor-controlled shunt compensators function as variable reactances operated in both the inductive and capacitive domains.

Distribution network communication system having branch connected repeaters

Abstract: Bidirectional addressable repeaters of a power line carrier communication system each include an address recognition and a receive and transmit control logic circuit having programmable zone and address identifying states for connection in plural repeating levels defining branch paths linking a central control terminal with multiple remote terminals via a distribution line network. Each repeater retransmits an interrogation message, provides its own repeater address modification, and remains in a response-wait status. The alerted repeaters define the predetermined route of branch paths for being sequentially activated by a response message. Simplified repeater response address formats are used and each repeater modified its address data upon response message retransmission. The desired sequentially occurring repeating transmissions are assured upon retransmission of both the interrogation and response messages.

Free carrier absorption in silicon

Abstract: Free carrier absorption in heavily doped layers reduces the useful photon flux in the photoconductive region of extrinsic Si infrared detectors. A simple theory is developed which predicts the transmissivity of such layers as a function of their sheet resistance and the wavelength of the radiation. Experimental data over the 2.5-20 µm wavelength and 5-500 Ω/square sheet resistance range are given for both diffused and ion-implanted layers and also for polysilicon gases. The temperature dependence of both transmissivity and sheet resistance is investigated from 20 to 300 K.

Free Carrier Absorption in Silicon

Abstract: Free carrier absorption in heavily doped layers reduces the useful photon flux in the photoconductive region of extrinsic Si infrared detectors. A simple theory is developed which predicts the transmissivity of such layers as a function of their sheet resistance and the wavelength of the radiation. Experimental data over the 2.5-20 /spl mu/m wavelength and 5-500 Omega/square sheet resistance range are given for both diffused and ion-implanted layers and also for polysilicon gates. The temperature dependence of both transmissivity and sheet resistance is investigated from 20 to 300 K.

Sand transport model of barchan dune equilibrium

Abstract: Erosion and deposition over a barchan dune near the Salton Sea, California, is modelled by book-keeping the quantity of sand in saltation following streamlines of transport. Field observations of near-surface wind velocity and direction plus supplemental measurements of the velocity distribution over a scale model of the dune are combined as input to Bagnold-type sand-transport formulae corrected for slope effects. A unidirectional wind is assumed. The resulting patterns of erosion and deposition compare closely with those observed in the field and those predicted by the assumption of equilibrium (downwind translation of the dune without change in size or geometry). Discrepancies between the simulated results and the observed or predicted erosional patterns appear to be largely due to natural fluctuation in the wind direction. Although the model includes a provision for a lag in response of the transport rate to downwind changes in applied shear stress, the best results are obtained when no delay is assumed. The shape of barchan dunes is a function of grain size, velocity, degree of saturation of the oncoming flow, and the variability in the direction of the oncoming wind. Smaller grain size or higher wind speed produce a steeper and more blunt stoss-side. Low saturation of the inter-dune sandflow produces open crescent-moon-shaped dunes, whereas high saturation produces a whaleback form with a small slip face. Dunes subject to winds of variable direction are blunter than those under unidirectional winds. The size of barchans could be proportional to natural atmospheric scales, to the age of the dune, or to the upwind roughness. The upwind roughness can be controlled by fixed elements or by the sand is saltation. In the latter case, dune scale may be proportional to wind velocity and inversely proportional to grain size. However, because the effective velocity for transport increases with grain size, dune scale may increase with grain size as observed by Wilson (1972).

Mechanism of CVD Thin Film SnO2 Formation

Abstract: The kinetic mechanism of CVD deposition has been studied for (i) reaction at 675°–940°C for and , (ii) reaction at 400°–807°C for and , and (iii) reaction at 425°–578°C for and . In combination with the available literature data, the results of the present investigation have been interpreted to show atomic oxygen as the adsorbed species and tin‐containing gas as the gaseous reactant in both the direct oxidation reactions (Rideal‐Eley mechanism). The hydrolysis reaction is the only thermally unactivated one in the group and proceeds by the collision of molecules on four adsorbed (symmetrically) water molecules on the surface. The open tube cold wall horizontal reactor has been established as an ideal equipment for the kinetic mechanism delineation of all CVD reactions.

Instability of Cylindrical Voids in Alumina

Abstract: It is shown from experimental observation that cylindrical voids in polycrystalline alumina are unstable. When isothermally annealed, they undergo various configurational changes, in accordance with the theoretical prediction, prior to an ultimate breakup into rows of spherical voids. The breakup occurs by ovulation, if the aspect ratio is appropriate. If the required aspect ratio is not met, cylindrical voids are directly transformed into spherical voids by spheroidization. The predominant mechanism for void breakup on thermal anneal confirms a model for surface-diffusion-control material transport. The estimated surface-diffusion coefficients at the experimental annealing temperatures agree, within an order of magnitude, with the values reported in the literature.

Precipitation of carbides in low-carbon Fe-AI-C alloys

Abstract: High-purity Fe-C alloys containing up to 5.8 pct Al were quenched from 730°C, then aged at temperatures up to 400°C. Precipitation of a carbide transition phase (presumably e) and of cementite were followed by transmission electron microscopy, coercive force measurements, and changes in yield strength. The presence of aluminum increases the temperature at which cementite begins to precipitate during aging. This effect is similar to that produced by silicon in ferrite, and opposite to that produced by manganese. It is suggested that the effects of Si, Mn, and Al on cementite precipitation from ferrite arise from the effects of these elements on the stability of cementite, as reflected in the equilibrium partition of carbon between cementite and ferrite.

Current limiting circuit breaker

Abstract: A molded case current limiting circuit interrupter includes a pair of pivoting contact arms each supporting a contact and being connected to wiring terminals such that current flows through the contact arms in opposite directions. One of the contact arms has a movable pivot point. A magnetic drive slot motor device is provided to generate electrodynamic contact opening force upon the contact arms during short circuit conditions. A high-speed magnetic trip device releases the operating mechanism under short circuit conditions to move the arm pivot point before the contact arms reclose. A spring latch may be provided to latch the upper contact arm in a contact-separated position during short circuit conditions until such time as the overcurrent flow through the breaker operates a thermal and magnetic trip mechanism to move an operating mechanism to the tripped position. Alternatively, a cam may be provided which is connected by a link to the upper contact arm and positioned such that upon short circuit conditions the contact opening motion of the upper contact arm caused by electrodynamic repulsion forces will cause the connecting link to rotate the cam and move the armature of the magnetic trip device to actuate the trip mechanism and release the operating mechanism to the tripped position, thereby preventing reclosing of the contact arms before the operating mechanism is able to trip. The operating mechanism includes a bracket to allow normal contact reset yet provide a positive closed contact indication if the contacts are welded together. An anti-rebound contact arm shock absorber is provided which is made of material having a high mechanical hysteresis loop to provide maximum energy dissipation.

Current limiting circuit interrupter with improved operating mechanism

Abstract: A current limiting circuit interrupter includes two parallel pivoting contact arms carrying contacts at the ends thereof. The upper contact arm is pivoted upon a carriage which is in turn pivotally mounted upon a mechanism frame. A latch rod is movably secured in arcuate slots in the sides of the mechanism frame. When the circuit interrupter is in the closed circuit position, a pair of springs connected between the latch rod and the carriage urges the latch rod against a reaction surface of the upper contact arm to provide contact closing pressure. Upon occurrence of severe overload current conditions, the upper contact arm pivots upon the carriage, moving the latch rod within the arcuate slots to release the contact closing pressure, allowing the springs to move the latch rod against a latching surface of the upper contact arm to latch the upper contact arm in the open circuit position.

EBT: A Comprehensive Test Generation Technique for Highly Sequential Circuits

Abstract: A new test generation technique for highly sequential circuits, utilizing functional models, with ability to produce tests for specific faults while avoiding races, is presented.

Current limiting circuit breaker with integral magnetic drive device housing and contact arm stop

Abstract: A current limiting circuit interrupter comprises a molded case, separable contacts disposed in the case, the contact arms supporting one of the contacts, an operating mechanism connected to the contact arm to move the arm between open and closed positions, and a slotted magnetic drive device generating electrodynamic force on the contact arm during extreme overcurrent conditions to rapidly separate the contacts The magnetic drive device includes a molded housing forming a slot having insulated walls disposed about the contact arm, and a stack of U-shaped laminations of magnetic material fitted into the housing The space between opposing walls of the housing is slightly less than the thickness of the lamination stack so that the laminations may be snugly press-fitted into the housing The housing is then secured to the case in such a manner that the laminations are captured and securely positioned without the need for rivets or other fastening means extending through the lamination stack The housing also includes molded recesses for receiving a compression spring to produce contact force when the contacts are in the closed position, and a molded stop member to limit the movement of the contact arm when the breaker is in the open position

Multiprocessor for providing fault isolation test upon itself

Abstract: An improved multiprocessor system for providing fault isolation test upon itself is described incorporating at least a first and second digital processor, a first, second and third memory and means for switching in one memory in place of another. In addition, methods are provided for fault isolation test in a multiprocessor system and for protecting the contents of one or more selected memories.

Mandrel for hydraulically expanding a tube into engagement with a tubesheet

Abstract: A mandrel for hydraulically expanding tubes into engagement with a tubesheet, the body of the mandrel being coated with an electrically isolating impermeable membrane and having an eddy current coil adjacent the leading end thereof, the tube into which the mandrel is placed and the body of the mandrel serving as leads for operating the eddy current coil in order to determine when the leading end of the mandrel is adjacent the inner edge of the tubesheet and a mandrel having a portion formed from wire rope so that the mandrel is flexible and can fit into a tube adjacent a hemispherical head.

Programmable AC electric energy meter having radiation responsive external data interface

Abstract: An electric energy meter has a programmable time based measuring system carried in a sealed enclosure for mounting the meter at a metering location. A radiation sensitive external data interface receives and transmits data encoded radiations through a transparent communications window of the enclosure. Pulse data is processed by the external data interface in serial data bit transmissions in and out of the measuring system for programming, readout and testing of the system.

Integrated solar cell array

Abstract: An integrated array of solar cells, each cell having a positive and a negative electrode, is disclosed. A first grid comprising a plurality of non-intersecting electrically conductive members is affixed to an insulating substrate. Each single individual member of this grid forms the negative electrode of an individual cell of the array. Overlying and affixed to the negative electrodes and the surface of the substrate between these electrodes is a semiconductor layer of a first conductivity type. Isolated (i.e., non-touching or non-abutting) semiconductor regions of a second conductivity type form a plurality of PN junctions with the semiconductor layer. These P-N junctions are the active areas of the individual cells of the array. Each of the isolated semiconductor regions of the second conductivity type is solely coupled to an individual member of another grid whose members form the positive electrodes of the individual cells. Electrical interconnection is made through a non-active region of the semiconductor layer to couple the cells comprising the array in series circuit relationship.

Tracking solar energy concentrator

Abstract: A solar energy concentrator including individually curved mirror slats arranged on a truss-type support structure to collectively form a substantially arcuate surface for concentration of incident radiation upon an elongated absorber. The reflector and absorber are fixed relative to one another by truss members, and the combined assembly is reciprocatingly rotatable by a linear actuator for tracking the position of the sun. The absorber includes fluid transfer tubes enclosed in a vacuum sealed multiple glass tube assembly.

Method for efficiently generating white light with good color rendition of illuminated objects

Abstract: Method and device for efficiently generating white light with good color rendition of illuminated objects. This is achieved by blending three different colors of light, namely, a green to yellow-green color of light, an orange to red color of light, and a purplish-blue to greenish-blue color of light. The relative intensities of the blended colors of light are selected to produce white light of predetermined ICI coordinates. The resulting blended light has at most only a limited amount of radiations of a wavelength shorter than 430 nm and at most only a limited amount of radiations of a wavelength longer than 630 nm. Also, the blended light has at most only a limited amount of radiations of a wavelength of about 575 nm and at most only a limited amount of radiations of a wavelength of about 500 nm.

Direct contact heat exchanger with phase change of working fluid

Abstract: A direct contact thermal storage heat exchanger which utilizes the liquid-vapor phase change of a working fluid within the heat exchanger, and energy generation systems incorporating the heat exchanger. The heat exchanger is particularly useful in combination with a solar energy receiver. The heat exchanger includes an insulated pressure vessel packed with pebbles or spheres. Working fluid in the vapor phase from a solar heat source enters the unit and condenses, transferring thermal energy to the pebbles. The liquid level of working fluid about the pebbles is decreased during this mode of operation. When it is desirable to release this stored energy the liquid level is increased, and the energy is transferred to the working fluid which forms a vapor, and can be used to drive a turbine or other prime movers.

Kinetics of Tungsten Deposition by the Reaction of WF 6 and Hydrogen

Abstract: Experimental rate data from a number of investigations on the chemical vapor deposition of tungsten by the hydrogen reduction of were analyzed to determine the reaction mechanisms which controlled the process under experimental conditions in which mass transport limitiation was absent. Rate‐controlling mechanisms were identified by comparing reaction orders obtained from the experimental data with those obtained from rate equations derived for each possible rate‐controlling step. Where the reactant stream was expected to remain streamlined and only slightly heated through contact with the tungsten substrate, the rate‐controlling mechanism was determined to be the dissociation of molecules adsorbed on the substrate. The activation energy for this process step was 67,000 J/mole. The reaction orders with respect to and were zero and one‐half, respectively. With experimental conditions more conducive to gas stream turbulence and stream heating, deposition rate was controlled by homogeneous gas phase reactions also having an activation energy of about 67,000 J/mole. The reaction order for this mechanism was 2 with respect to both reactants.

Resin impregnated aromatic polyamide covered glass based slot wedge for large dynamoelectric machines

Abstract: An iron engaging slot wedge, for use in coil slots of dynamoelectric machines is made of a glass fiber core impregnated with a cured thermoset resin, and covered on at least two sides with a facing layer of a porous aromatic polyamide mat, impregnated with a cured thermoset resin.

Current sensing transducer for power line current measurements

Abstract: A current sensing transducer includes a conductive current divider including a branch path for conducting a fractional current proportional to a current to be sensed and being applied through the divider. A compensated transformer includes a primary circuit responsive to the fractional current and two secondary windings. An amplifier circuit controls the current input to one secondary winding in response to the output of the other secondary winding so that the flux of the primary circuit is virtually compensated in the core and the secondary winding current is a measure of the current to be sensed.

Versatile, electrified space dividing wall panel system

Abstract: A versatile, electrified space dividing wall panels system including wall panels having baseboard raceways adjacent their bottom edges and electrically connected terminal blocks at each end of the baseboard raceway which include longitudinally and outwardly directed male electrical terminals adapted to receive female connectors from a source of electrical power or transfer electrical power to an adjacent wall panel. Each of said terminal blocks are adapted to receive plug-in convenience outlets in each side thereof through the raceway side walls.

Phase Relations in the System Si3N4‐SiO2‐MgO and Their Interrelation with Strength and Oxidation

Abstract: Phase relation studies of Si3N1, SiO2, and MgO have established three important subsolidus tie lines, viz. Si3N4-MgO, Si3N4-Mg2SiO4, and Si2N2O-Mg2SiO4 for nonoxidizing fabrication conditions. Strength measurements at 1400°C show that optimum strengths are obtained for compositions approaching the Si3N4-MgO and Si3N4-Si2N2O tie lines and that inferior strengths are obtained for compositions approaching the Si3N4-Mg2SiO4 tie line. Oxidation measurements at 1375°C show that the oxidation kinetics depend on the content of MgO and Mg2SiO4 phases. Optimum oxidation resistance is observed for compositions approaching the Si3N4-Si2N2O tie line. Strength and oxidation results are discussed with regard to phase equilibrium considerations.

Multilayered high voltage grading system for electrical conductors

Abstract: An insulated electrical member is made, having in combination, an electrical member covered with insulation and a conducting varnish, where an abrasion resistant stress grading system covers at least part of the conducting varnish, the stress grading comprising: (1) a first base layer of resinous paint containing non-linear SiC having a resistivity value of between 2,000 to 4,000 Meg. Ohm/Square, in contact with the conducting varnish, (2) a second overlapping layer of resinous paint containing non-linear SiC having a resistivity value of between 4,000 to 6,000 Meg. Ohm/Square and containing at least one fibrous support, covering the first base layer and (3) an overcoat of an arc and track resistant resinous insulating varnish; where, at the point of overlap of the SiC layers, the thickness ratio of the base SiC layer:overlapping SiC layer is from 1:1 to 1:15.

Automatic transfer control device

Abstract: An automatic control transfer device for selectively energizing an electrical distribution system from a pair of electrical power sources. The device includes means for sensing electrical conditions on both of the sources and programmable electronic digital logic to selectively energize associated circuit interrupters for switching a distribution system between the two sources. A plurality of time delay functions are provided utilizing a separate oscillator for each function, each oscillator providing input to a common digital counter. The device senses the status of associated circuit interrupters to provide interlocking and lockout functions as well as proper switching commands for either two- or three-circuit interrupter systems. Means are also provided for testing the entire device without initiating an actual source transfer.