Showing papers by "Westinghouse Electric published in 1985"

Impurities in silicon solar cells

Abstract: Metallic impurities, both singly and in combinations, affect the performance of silicon solar cells. Czochralski silicon web crystals were grown with controlled additions of secondary impurities. The primary electrical dopants were boron and phosphorus. The silicon test ingots were grown under controlled and carefully monitored conditions from high-purity charge and dopant material to minimize unintentional contamination. Following growth, each crystal was characterized by chemical, microstructural, electrical, and solar cell tests to provide a detailed and internally consistent description of the relationships between silicon impurity concentration and solar cell performance. Deep-level spectroscopy measurements were used to measure impurity concentrations at levels below the detectability of other techniques and to study thermally-induced changes in impurity activity. For the majority of contaminants, impurity-induced performance loss is due to a reduction of the base diffusion length. From these observations, a semi-empirical model which predicts cell performance as a function of metal impurity concentration was formulated. The model was then used successfully to predict the behavior of solar cells bearing as many as 11 different impurities.

A Grain-boundary Defect Model for Instability/stability of a ZnO Varistor

Abstract: A defect model for the grain-boundary barrier has been proposed to explain the phenomena of voltage instability/stability of the ZnO varistor. The key element of the proposed model is the zinc interstitials which are present in the depletion layer as excess zinc, arising from the non-stoichiometric nature of ZnO. Both instability and stability have been described in terms of diffusion of these interstitials in the depletion layer, followed by chemical interactions with defects at the grain-boundary interface. Finally, a large body of experimental data is presented to indirectly validate the proposed defect model.

Systems with human monitors: a signal detection analysis

Abstract: Automated factories, the flightdecks of commercial aircraft, and the control rooms of power plants are examples of decision-making environments in which a human operator performs an alerted-monitor role. These human-machine systems include automated monitor or alerting subsystems operating in support of a human monitor. The automated monitor subsystem makes preprogrammed decisions about the state of the underlying process based on current inputs and expectations about normal/abnormal operating conditions. When alerted by the automated monitor subsystem, the human monitor may analyze input data, confirm or disconfirm the decision made by the automated monitor, and take appropriate further action. In this paper, the combined automated monitor-human monitor system is modeled as a signal detection system in which the human operator and the automated component monitor partially correlated noisy channels. The signal detection analysis shows that overall system performance is highly sensitive to the interaction between the human's monitoring strategy and the decision parameter, Ca, of the automated monitor subsystem. Usual design practice is to set Ca to a value that optimizes the automated monitor's detection and false alarm rates. Our analysis shows that this setting will not yield optimal performance for the overall human-machine system. Furthermore, overall system performance may be limited to a narrow range of realizable detection and error rates. As a result, large gains in system performance can be achieved by manipulating the parameters of the automated monitor subsystem in light of the workload characteristics of the human operator.

Diagnostic system and method

Abstract: A diagnostic system wherein a central diagnostic center receives sensor data relative to the operating condition of a plurality of remote plants. Each plant records certain sensor signals and transmits them at respective prescheduled transmission times. If certain activation limits are exceeded, a data link with the diagnostic center is immediately established so that the data may be transmitted ahead of its normally scheduled transmission time in order that an immediate diagnostic analysis be on the plant. A communication link between the plant and diagnostic center is kept open for a predetermined period of time in which more data may be sent from the plant to the diagnostic center, and results and instructions, sent from the diagnostic center back to the plant

Rule based diagnostic system with dynamic alteration capability

Abstract: Sensor based diagnostic apparatus for performing on-line realtime monitoring of an industrial or other operating system. The diagnostic apparatus has a rule network for propagation of belief leading to one or more possible malfunctions of equipment in the operating system. The propagation of belief is dynamically altered as a function of the operating conditions of the sensors themselves.

Gas-Insulated Cables

Abstract: Compressed-gas insulated transmission lines or cables have been in service since 1968, with over 13 km (circuit length) in operation worldwide at voltages from 145 to 550 kV. The design philosophy and development are reviewed for the "rigid", flexible, and semi-flexible isolated phase lines, the three-conductor lines and the prototype dc gas-insulated cable system. The various designs of insulators, conductors, enclosures, particle traps, and terminations are described, together with the techniques for grounding and corrosion protection, factory and site testing, fault diagnostics, and calculation of current ratings.

Getting Lost: A Case Study in Interface Design:

Abstract: This paper describes an application of principles of spatial data management to correct for an information handling problem, the “getting lost” phenomena in a large multiple display network. The application is the computerization (e.g., electronic book) of a book of procedures for use by nuclear power plant operators during accident conditions.

Predictive model reference adaptive controller

Abstract: Apparatus and method for controlling the output of a dynamic system which is susceptible to changing dynamic characteristics. The desired present and future outputs of the system are applied to a predictor which determines the inputs to a model reference adaptive control subsystem from which the actual outputs are produced. The predictor uses an impulse model of the subsystem to simulate and predict future outputs. The adaptive control subsystem includes adjustable gain feedback or controlloops which are adjusted to make the dynamic system appear to have constant characteristics even when its dynamic characteristics are changing. A reference model of the dynamic system is used as the basis for the gain adjustments. The equation weights for the mathematical impulse model used by the input predictor are derived from the reference model of the adaptive control subsystem, and remain constant throughout the operation of the controller.

Methods of servicing an elevator system

Abstract: A method of integrating an expert system having a knowledge base of elevator trouble-shooting information into the working environment of elevator service personnel, without special training of such personnel, and without compromising the security of the knowledge base. The method includes an interactive initialization procedure which includes successive, successful user and knowledge base initiated communication links between the user and knowledge base, before actual access to the knowledge base is permitted.

Method and apparatus for clearing short-circuited, high-voltage cathodes in a sputtering chamber

Abstract: A method and apparatus for vaporizing any flakes of sputtering target material which short circuit high voltage cathodes during the sputtering of a coating on a substrate such as nuclear fuel pellet positioned in the vacuum chamber of a sputtering device. A separate low voltage, high current auxiliary power source is used to evaporate the shorting flakes. The present method and apparatus reduces the process recovery time in the event of a shorting flake from as long as 6 hours down to as little as 5 minutes without compromising the purity of the sputtered coating. The auxiliary power source may be an ac source which is preferably connected in series with the shorting flake so that current from the ac source will cease as soon as the shorting flake is evaporated. A ballast and/or short circuit indicating device may also be provided in series with the ac source in order to limit the ac current and in order to indicate the presence of shorting flakes. The system may be automated to automatically determine conditions indicative of the existence of a shorting flake and to thereupon automatically initiate a shorting flake evaporation cycle.

Impedance of the Residential Power-Distribution Circuit

Abstract: This paper presents measurements and analysis of the impedance of residential power-distribution circuits at frequencies from 5 to 20 kHz. These frequencies are used by systems such as distribution-line carriers which use the power distribution circuit as a communications medium. Residential impedances are determined by the distribution transformer secondary windings, entrance cables, house wiring, and electrical loads. Impedance measurements of these components and measurements at four residences are presented.

Microanalytical study of the heterogeneous phases in commercial Al-Zn-Mg-Cu alloys

Abstract: X-ray microanalysis and Convergent Beam Diffraction (CBD) studies were conducted on the second phase constituent and dispersoid particles in 7075 and 7475 aluminum alloys. Partial substitution of alloying elements was found to occur in all the second phase particles causing small deviations from the stoichiometric compositions reported for the binary and ternary compounds. The coarse constituent phases were identified to be Al7Cu2Fe, (Al,Cu)6(Fe,Cu), Mg2Si, α-Al12Fe3Si, amorphous silicon oxide, and a modified Al6Fe compound in decreasing order of abundance. The dispersoid particles were Al18Mg3Cr2 compound, and they formed in both triangular and spherical morphologies. Their compositions were found to vary slightly with the aging treatment. The crystal structure of the dispersoid phase consisted of a disordered form of a cubic structure (Fd3m) reported for the Al18Mg3Cr2 compound. The uniqueness of CBD analysis in the crystal structure determination is emphasized.

Integrated circuit having outputs configured for reduced state changes

Abstract: A logic arrangement for low power integrated circuits which reduces the number of state changes at the synchronously clocked parallel outputs of the integrated circuit. Logic is included which determines the number of output lines which would normally change state when the next output word is clocked onto the output lines. Additional logic determines whether this number is greater than or equal to a predetermined number, being one-half the number of output lines for even numbers of output lines. When the number of state changes will exceed this number, the output word is complemented before being clocked onto the output lines. An extra output line is used to signal the circuitry connected to the output lines that the output states have been complemented. When the number of state changes equals the predetermined number, the output word is complemented only if the previous output word was complemented.

Active power conditioner system

Abstract: At least two active conditioners are connected in series with a common DC source, and are mounted as a unit between two pairs of AC terminals to act either as a tie-in link between two AC power sources, as a buck/boost regulator between one AC power source and its load, or as VAR compensator as well as active power conditioner between phases of a multiphase AC option.

Uninterruptible power supply system and load transfer static switch for such a system

Abstract: A UPS system which operates initially in a commutation mode allowing commutation of the static transfer switch provided on the primary supply lines, and wherein the standby source is kept energized so as to operate to commutate such transfer switch through the inverter just before initiating UPS mode of operation.

Automatic touch screen calibration method

Abstract: A method for automatically calibrating a touch screen used in conjunction with a graphic display is executed prior to every interactive session. Three points, defining perpendicular axes, are displayed and an operator is instructed to touch the touch screen at each of the points in succession. Coordinates for the three points output by the touch screen are checked for reasonableness and perpendicularity. If these checks are passed, a coordinate translation matrix is generated for converting touch screen coordinates into display coordinates.

Air electrode material for high temperature electrochemical cells

Abstract: Disclosed is a solid solution with a perovskite-like crystal structure having the general formula La.sub.1-x-w (M.sub.L).sub.x (Ce).sub.w (M.sub.S1).sub.1-y (M.sub.S2).sub.y O 3 where M L is Ca, Sr, Ba, or mixtures thereof, M S1 is Mn, Cr, or mixtures thereof and M S2 is Ni, Fe, Co, Ti, Al, In, Sn, Mg, Y, Nb, Ta, or mixtures thereof, w is about 0.05 to about 0.25, x+w is about 0.1 to about 0.7, and y is 0 to about 0.5. In the formula, M L is preferably Ca, w is preferably 0.1 to 0.2, x+w is preferably 0.4 to 0.7, and y is preferably 0. The solid solution can be used in an electrochemical cell where it more closely matches the thermal expansion characteristics of the support tube and electrolyte of the cell.

Turbine blade vibration detection apparatus

Abstract: Sensors are disposed equally about a blade row in a turbine with each sensor providing an output signal responsive to a passing blade. A blade is selected for monitoring purposes by location relative to a reference position ± some angular distance constituting a small window. As the selected blade passes a sensor, its output signal provides a pulse, and is gated. The sequential pulses of the sensors form a pulse train. An FM detector is provided to derive vibration information.

Optical three-dimensional digital data acquisition system

Abstract: The range of objects from a television camera is obtained by projecting a series of patterns of uniquely coded stripes of light onto the objects at an oblique angle to the optical axis of the camera and capturing in the camera the coded light signals reflected by the objects. Through proper selection and scaling of a coordinate system and related coding of the light stripes, the range of the object is determined for each pixel by simply subtracting one coordinate of the pixel from the binary coded light signal reflected into the pixel.

Switch bypass circuit for power line communication systems

Abstract: A signal bypass apparatus for a power line distribution switch incorporates two portions that are electrically connected together in parallel with a power line switch. Each portion comprises a transformer that is connected electrically in parallel with an inductor. A capacitor is connected between the transformer and the inductor of each portion and the assembly is connected between one side of a power line distribution switch and ground. The other portion of the bypass apparatus is similarly configured and connected between the other side of the power line distribution switch and ground. In one embodiment, the bypass apparatus is electrically connected to a transceiver.

Aneurysm clip motion during magnetic resonance imaging: in vivo experimental study with metallurgical factor analysis.

Abstract: Because of various mechanical, metallurgical, and commercial constraints, aneurysm clips are manufactured from different alloys, including several stainless steel and cobalt alloys. Some of the steels contain volume fractions of the crystal phase known as martensite. Martensitic alloys have body-centered cubic structure, are prone to stress corrosion failure, and are ferromagnetic. Martensitic steel can be displaced like a compass needle when exposed to a magnetic field such as that generated during magnetic resonance imaging (MRI). The force exerted by the magnetic field is proportional to the volume fraction of the magnetic phase. We investigated the martensitic content and magnetic field-induced displacement of 12 common aneurysm clips. Four clips of each of the following types were examined: Sugita, Sundt-Kees Multi-Angle, Heifetz (two types), Vari-Angle McFadden, Yasargil (two types), Scoville, Mayfield, Vari-Angle, Pivot, and Kapp. Phase homogeneity and crystal structure were analyzed by x-ray diffraction using a Phillips x-ray diffractometer. Clip deflection in an Oxford Research Systems MRI spectrometer was measured in our in vivo rat abdominal aortic aneurysm model. Results showed that the volume fraction of the martensitic phase in the various clips correlated with the magnitude of the deflection. Among the clips examined, the Yasargil, Sugita, Heifetz Elgiloy, and Vari-Angle McFadden had a nonmartensitic composition and did not deflect in the magnetic field. The Scoville contained 5% martensite and deflected only marginally. Martensite comprised 35% of the Mayfield clip, which deflected 45 degrees, and 90% of the Heifetz, Vari-Angle, Pivot, and Sundt-Kees Multi-Angle clips, which deflected approximately 70 degrees or slipped off the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Temperature and strain rate dependence of stress-strain behavior in a nickel-base superalloy

Abstract: The temperature and strain rate dependence of yield and work hardening behavior in elevated temperature stress-strain testing was investigated in the nickel-base superalloy UDIMET 115. This alloy was heat treated to produce a bimodal distribution of hyperfine and coarse γ1 precipitates. Yield behavior is shown to be controlled primarily by dislocation pair cutting of the hyperfine precipitates. Stage II work hardening appears to be governed mainly by the dislocation networks generated on the coarse precipitates as these are bypassed under the Orowan mechanism. Analysis of Stage III work hardening using ϕvs σ plots shows that a steady state exists for the stress-strain deformation of this system. Results are also reported on extremely strong serrated flow at moderately elevated temperatures and a high temperature ductility minimum.

Process for fabricating a zirconium-niobium alloy and articles resulting therefrom

Abstract: Articles, such as tubing, which have excellent corrosion resistance to steam at elevated temperatures and to hydriding, are produced from zirconium alloys containing 0.5 to 2.0 percent niobium, up to 1.5 percent tin, and up to 0.25 percent of a third alloying element such as iron, chromium, molybdenum, vanadium, copper, nickel and tungsten. The articles are formed by beta-treating the alloy, initially deforming the same at a temperature below 650° C. and further deforming the same through cold working stages also below 650° C., annealing the material between the cold working stages at a temperature between 500°-650° C., and final annealing the same at a temperature below 650° C. to provide articles having a microstructure of fine precipitates of less than about 800 Å, homogeneously dispersed throughout the zirconium.

Acoustical Technology Applications in Electrical Insulation and Dielectrics

Abstract: Acoustical waves travel by molecular interaction, and as a consequence, wave attenuation and transit time can be extremely sensitive to changes in the media in which they propagate. With careful acoustic measurements, a wide variety of media properties can be monitored. These range from variations in gas mixtures and pressure, to changes in material density, porosity, and crystal size and orientation. Acoustical technology can also be applied in the listening mode to sense the tiny acoustic emissions from partial discharges in dielectrics, and from stress, strain, and other events. Many of these acoustic techniques are ideal for applying to the science of electrical insulation and dielectrics, and in this paper these different methods are described and evaluated. The subject is introduced with an outline of ultrasonic partial discharge (PD) diagnostics and nondestructive evaluation, with emphasis on acoustic factors which affect accuracy. It is then shown how the use of acoustic waveguides can improve diagnostic PD measurements in hostile and inaccessible locations. In a completely different application, a technique is described in which sound velocity measurements in gas mixtures are used for predicting electrical strength. Other valuable acoustical applications which are outlined are the monitoring of sounds from bouncing particles on metal surfaces and from gas bubbles generated in liquid dielectrics. From this latter phenomenon the temperature of a hot metal surface in a liquid can be estimated. A related subject which is also discussed is the attenuation of sound waves by gas bubbles in a liquid dielectric.

System for assembling electronic component kits

Abstract: A system for machine assembly of component kits for electronic printed circuit boards is disclosed. Components for assembling the kits are stored in a plurality of standardized machine recoverable trays, more specifically a multi-level carousel. An elevator transports trays between storage and an automated work station where components are removed to construct the component kits.

Speech enhancement system having dynamic gain control

Abstract: An arrangement for a speech enhancement processor which maintains the processed speech at a constant level regardless of large changes in the associated noise level. The composite speech and noise signal is applied to a first AGC circuit and then to a speech enhancement system which removes tonal, impulse, and wideband noises from the signal. The extracted noise power estimates are subtracted from the constant amplitude signal to provide a gain control signal value to which the gain of a second variable gain amplifier is inversely proportional. The amplifier multiplies the processed speech output from the enhancement system and, because of the variable gain control, provides an output speech signal having short-term amplitude levels which correspond to those of the input speech signal, and having a constant long-term amplitude level.

Optical scanning apparatus for indicia imprinted about a cylindrical axis

Abstract: An optical scanner employed in a radioactive environment for reading indicia imprinted about a cylindrical surface of an article by means of an optical system including metallic reflective and mirror surfaces resistant to degradation and discoloration otherwise imparted to glass surfaces exposed to radiation.

Hand-held wireless computer controller system

Abstract: A hand-held, battery powered, wireless control station transmits alphanumeric characters and control functions to a receiver interfaced with a host computer. The control station includes a microcomputer which converts keyboard signals into a secured character code and transmits the secured character code to a computer interface transceiver using a frequency shift key modulation technique. The keyboard is a multiple function keyboard having plural shift keys allowing several character codes for each key. The computer interface transceiver only recognizes or accepts secured character codes. For the character codes accepted the computer interface transceiver forwards the character to the host computer via an RS 232 interface link. The computer interface transceiver also transmits the secured character code back to the hand-held control station which then displays the characters on a display confirming for the operator receipt of the character by the computer end transceiver. In addition, messages which originate in the computer can be transmitted to the hand-held control station and displayed on the display therein in a secure manner.