scispace - formally typeset
Search or ask a question

Showing papers by "General Electric published in 1980"


Book
30 Apr 1980
TL;DR: In this paper, the authors present a mathematical model of the Synchronous Machine and the effect of speed and acceleration on the stability of a three-phase power system with constant impedance load.
Abstract: Preface.Part I: Introduction.Chapter 1: Power System Stability.Chapter 2: The Elementary Mathematical Model.Chapter 3: System Response to Small Disturbances.Part II: The Electromagnetic Torque.Chapter 4: The Synchronous Machine.Chapter 5: The Simulation of Synchronous Machines.Chapter 6: Linear Models of the Synchronous Machine.Chapter 7: Excitation Systems.Chapter 8: Effect of Excitation on Stability.Chapter 9: Multimachine Systems with Constant Impedance Loads.Part III: The Mechanical Torque Power System Control and Stability.Chapter 10: Speed Governing.Chapter 11: Steam Turbine Prime Movers.Chapter 12: Hydraulic Turbine Prime Movers.Chapter 13: Combustion Turbine and Combined-Cycle Power Plants.Appendix A: Trigonometric Identities for Three-Phase Systems.Appendix B: Some Computer Methods for Solving Differential Equations.Appendix C: Normalization.Appendix D: Typical System Data.Appendix E: Excitation Control System Definitions.Appendix F: Control System Components.Appendix G: Pressure Control Systems.Appendix H: The Governor Equations.Appendix I: Wave Equations for a Hydraulic Conduit.Appendix J: Hydraulic Servomotors.Index.

3,249 citations


Journal ArticleDOI
TL;DR: This paper provides a unified discussion of the Delaunay triangulation and two algorithms are presented for constructing the triangulations over a planar set ofN points.
Abstract: This paper provides a unified discussion of the Delaunay triangulation. Its geometric properties are reviewed and several applications are discussed. Two algorithms are presented for constructing the triangulation over a planar set ofN points. The first algorithm uses a divide-and-conquer approach. It runs inO(N logN) time, which is asymptotically optimal. The second algorithm is iterative and requiresO(N 2) time in the worst case. However, its average case performance is comparable to that of the first algorithm.

1,460 citations


Journal ArticleDOI
Jens Feder1
TL;DR: From electron microscopic examination of uranyl acetate stained ferritin, it is concluded that this iron storage protein adsorbs on carbon in a way consistent with results for random sequential adsorption.

554 citations


Journal ArticleDOI
TL;DR: An analysis of this technique is extended to the case when a linear filter appears in the auxiliary signal path and a general solution to this problem is obtained.
Abstract: A technique known as a "multiple correlation cancellation loop" and also as the "LMS algorithm" is widely used in adaptive arrays for radar, sonar, and communications, as well as in many other signal processing applications. In this paper an analysis of this technique is extended to the case when a linear filter appears in the auxiliary signal path. A general solution to this problem is obtained and several examples for narrow-band and broad-band signals are presented.

395 citations


Journal ArticleDOI
23 May 1980-Science
TL;DR: The sintered masses are produced on a commercial scale and are increasingly used as cutting tools on hard or abrasive materials, as wire-drawing dies, in rock drills, and in special high-pressure apparatus.
Abstract: Diamond or cubic boron nitride particles can be sintered into strong masses at high temperatures and very high pressures at which these crystalline forms are stable. Most of the desirable physical properties of the sintered masses, such as hardness and thermal conductivity, approach those of large single crystals; their resistance to wear and catastrophic splitting is superior. The sintered masses are produced on a commercial scale and are increasingly used as cutting tools on hard or abrasive materials, as wire-drawing dies, in rock drills, and in special high-pressure apparatus.

320 citations


Journal ArticleDOI
TL;DR: In this article, the adsorption of ferritin molecules onto both Lexan polycarbonate and carbon surfaces has been studied with the help of an electron microscope, and the amount of adsorbed is a sensitive function of both the pH and the salinity of the ferrin solution.

249 citations


Proceedings ArticleDOI
09 Apr 1980
TL;DR: An analysis of this technique is extended to the case when a linear filter appears in the auxiliary signal path and a general solution to this problem is obtained.
Abstract: A technique known as a "multiple correlation cancellation loop" and also as the "LMS algorithm" is widely used in adaptive arrays for radar, sonar, and communications, as well as in many other signal processing applications. In this paper, an analysis of this technique is extended to the case when a linear filter appears in the auxiliary signal path. A general solution to this problem is obtained and several examples for narrowband and broad-band signals are presented.

219 citations


Journal ArticleDOI
29 Feb 1980-Science
TL;DR: Direct evidence has been obtained for two mechanisms, first, recoil ejection from grains, and now release by natural etching ofalpha-recoil tracks, which have implications for radon emanation and for the storage of alpha-emitting radioactive waste.
Abstract: Preferential loss of uranium-234 relative to uranium-238 from rocks into solutions has long been attributed to recoiling alpha-emitting nuclei. Direct evidence has been obtained for two mechanisms, first, recoil ejection from grains, and now release by natural etching of alpha-recoil tracks. The observations have implications for radon emanation and for the storage of alpha-emitting radioactive waste.

210 citations


Journal ArticleDOI
TL;DR: Ions were used as mobile, membrane-bound carriers for selected gas species, these being introduced as the counter ions in ion-exchange membranes as mentioned in this paper, which could be useful in practical gas separations, giving longer operating life under certain adverse conditions.

188 citations


Journal ArticleDOI
TL;DR: This tutorial paper presents an iterative method for the separation of slow and fast modes, which removes the inconsistencies of the classical quasi-steady-state approach and systematically improves the accuracy of the lower order models.

182 citations


Journal ArticleDOI
TL;DR: In this article, a field test and analytical analysis of the HVDC-torsional interaction was carried out at the Square Butte HVDC terminal and the results showed that the changes resulted in stable operation.
Abstract: Tests on the the modern HVDC system at Square Butte conducted in October 1977 indicated that the HVDC terminal was interacting in an adverse way with an 11.5-Hz torsional mode of an adjacent turbine- generator unit. Subsequent analytical work duplicated the field test observations and was used to develop an understanding of the HVDC-torsional interaction phenomena. As a result of the analytical work, the control system of the HVDC terminal was modified and subsequent tests showed that the changes resulted in stable operation. The paper includes significant field test and analytical results.

Journal ArticleDOI
Ramon Nitzberg1
TL;DR: It is shown that the number of independent vector measurements required for the matrix estimator can be decreased by up to a factor of two.
Abstract: The optimum weights for an adaptive processor are determined by solving a particular matrix equation. When, as is usually true in practice, the covariance matrix is unknown, a matrix estimator is required. Estimating the matrix can be computationally burden some. Methods of decreasing the computational burden by exploiting persymmetric symmetries are discussed. It is shown that the number of independent vector measurements required for the estimator can be decreased by up to a factor of two.

Journal ArticleDOI
TL;DR: In this paper, the ionic conductivity of β-alumina has been measured in single crystals of single crystals grown from a melt of Na2O, MgO and Al2O3 at 1660 to 1730°C.

Patent
David M. Erdman1
25 Sep 1980
TL;DR: In this paper, a regulating circuit is provided for maintaining the evaporator at a reference temperature by controlling the output signal of an alternator which supplies energization power to winding stages of a brushless DC motor.
Abstract: Electronically commutated motor and control arrangements particularly adapted for use with refrigeration systems and methods of operating refrigeration systems are disclosed. In one form, a fan control means is provided for responding to temperature of a compartment being cooled by a refrigeration system; comparing the compartment temperature with a desired temperature; and varying the speed of an evaporator fan, thereby varying the movement of refrigerated air across an evaporator and into the compartment. A regulating circuit is provided for maintaining the evaporator at a reference temperature by controlling the output signal of an alternator which supplies energization power to winding stages of a brushless DC motor. By varying the energization level of the winding stages, a compressor, which is coupled to the motor, is caused to vary the flow rate of refrigerant through the evaporator so as to maintain the evaporator at the reference temperature. The regulating circuit includes means for responding to a signal from the fan control means, which is indicative of the fan speed and relative compartment cooling demand, for changing the reference temperature for the evaporator thereby to cause variance in the temperature of air moved about the evaporator by the fan for controlling temperature within the compartment. The regulating circuit also includes: means for limiting and controlling motor winding current to a maximum value; means for limiting motor speed to a predetermined low value; means for limiting and controlling motor speed to a maximum high value; means for assuring a minimum energization level for the motor winding stages; means for limiting the energization level of the winding stages to a maximum voltage value; and means for inhibiting motor operation if the evaporator temperature is less than a predetermined low temperature value.

Patent
17 Jul 1980
TL;DR: In this paper, a battery monitor circuit for rechargeable multicell batteries that provides a reliable indication of battery failure independent of temperature, load and age, by continuously comparing the impedance of the cells of the battery against each other.
Abstract: A battery monitor circuit for rechargeable multicell batteries that provides a reliable indication of battery failure independent of temperature, load and age, by continuously comparing the impedance of the cells of the battery against each other. Comparison means are provided responsive to a first voltage at a tapped terminal of the battery that divides the battery cells into two groups, and to a second voltage that represents a fraction of the battery voltage corresponding to the ratio of the number of cells in each group, said comparison means generating an error signal when said first and second voltages change so as to experience a reversal in relative magnitude, which is indicative of cell deterioration.

Journal ArticleDOI
TL;DR: In this paper, a flyback converter used as a battery charger is analyzed and applied to optimize the design of the snubber and clamp arrangement in a power transistor switching circuit.
Abstract: In power transistor switching circuits, shunt snubbers (dv/dt limiting capacitors) are often used to reduce the turn-off switching loss or prevent reverse-biased second breakdown. Similarly, series snubbers (di/dt limiting inductors) are used to reduce the turn-on switching loss or prevent forward-biased second breakdown. In both cases energy is stored in the reactive element of the snubber and is dissipated during its discharge. If the circuit includes a transformer, a voltage clamp across the transistor may be needed to absorb the energy trapped in the leakage inductance. The action of these typical snubber and clamp arrangements is analyzed and applied to optimize the design of a flyback converter used as a battery charger.

Patent
22 Dec 1980
TL;DR: In this article, an improved process for preparing a composite compact consisting of a mass of abrasive crystals, metal carbide, and a bonding medium is presented. And the resulting improved composite compact also is disclosed.
Abstract: Disclosed is an improved process for preparing a composite compact wherein a mass of abrasive crystals, a mass of metal carbide, and a bonding medium are subjected to a high-temperature/high pressure process for providing a composite compact. The sintered carbide mass supports the mass of abrasive crystals and bonding or catalyst metal, and the abrasive crystal grains are directly bonded to adjacent crystal grains in the mass thereof. Such improved process comprises disposing the mass of abrasive crystals in layers wherein the coarsest layer is closest to the carbide mass and is composed of crystals having a largest dimension of between about 75 and 500 microns and the finest layer is disposed farthest away in the carbide mass and is composed of crystals having a largest dimension of less than 10 microns. The abrasive crystals are selected from the group consisting of diamond and cubic boron nitride and preferably are diamond; the metal carbide preferably is tungsten carbide; and the bonding metal preferably is cobalt. The resulting improved composite compact also is disclosed.

Journal ArticleDOI
TL;DR: Very fine particles of magnetite, nickel ferrite, and cobalt ferrite were produced by grinding coarser powders in a ball mill with a carrier fluid and a surfactant.
Abstract: Very fine particles of magnetite, nickel ferrite, and cobalt ferrite were produced by grinding coarser powders in a ball mill with a carrier fluid and a surfactant. The particles were examined by means of chemical analysis, electron microscopy, x-ray diffraction, magnetic measurements, and Mossbauer spectroscopy. Properties were determined before and after removing the surfactant coating. The most significant observation was that in some systems a large fraction of the spins was pinned in extremely high anisotropy fields as a result of bonding to the surfactant molecules. Anomalous magnetic hysteresis behavior was also noted when the surfactant coating was present.

Journal ArticleDOI
TL;DR: It is shown that axial partial volume effects can account for the presence of artifacts in cranial transverse section CT reconstructions and that thin-slice scanning for sections where these artifacts are common is perhaps a more preferable solution.
Abstract: Dark streaks connecting the petrous bones are often observed in cranial transverse section CT reconstructions. These artifacts are usually only slightly diminished by two-pass beam hardening corrections. However, it is found that by narrowing the slice thickness the artifacts are substantially reduced. In this paper, it is shown that axial partial volume effects can account for the presence of the artifacts. These axial partial volume effects occur when, at any point in the slice, the object has axial variations in attenuation. In such cases the logarithm of the integrated intensity measured by the detector is not a linear function of the integrated attenuation (even for monochromatic beams). This nonlinearity causes inconsistencies in the data set which in turn can cause streaks in the image. We have studied the partial volume effect using computer simulation. Algorithms are presented whose purpose is to correct for these effects by estimating the axial variation using neighboring slices. These correction algorithms are successful in computer simulation cases but failed with clinical data. It is concluded that no practical correction method is viable unless overlap scanning is employed. However, thin-slice scanning for sections where these artifacts are common is perhaps a more preferable solution.

Patent
Rack H. Chung1
11 Jul 1980
TL;DR: A radiation curable coating composition comprising colloidal silica (B) acryloxy or glycidoxy functional silanes (C) non-silyl acrylsates and (D) catalylic amounts of UV light sensitive cationic and radical type photoinitiators is provided in this paper.
Abstract: A radiation curable coating composition comprising (A) colloidal silica (B) acryloxy or glycidoxy functional silanes (C) non-silyl acrylates and (D) catalylic amounts of UV light sensitive cationic and radical type photoinitiators is provided, which cures to a transparent hard coating exhibiting improved abrasion resistance.


Journal ArticleDOI
David R. Musser1
TL;DR: The main emphasis is on methods of ensuring convergence (finite and unique termination) of sets of rewrite rules and on the relation of this property to the equational and inductive proof theories of data types.
Abstract: This paper describes the data type definition facilities of the AFFIRM system for program specification and verification. Following an overview of the system, we review the rewrite rule concepts that form the theoretical basis for its data type facilities. The main emphasis is on methods of ensuring convergence (finite and unique termination) of sets of rewrite rules and on the relation of this property to the equational and inductive proof theories of data types.

Journal ArticleDOI
TL;DR: In this paper, the authors described the experiment objectives, system design, performance, and modes of operation of the Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission spacecraft.
Abstract: The Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission spacecraft is described, including the experiment objectives, system design, performance, and modes of operation. The instrument operates in the wavelength range 1150–3600 A with better than 2 arc sec spatial resolution, raster range 256 × 256 arc sec2, and 20 mA spectral resolution in second order. Observations can be made with specific sets of 4 lines simultaneously, or with both sides of 2 lines simultaneously for velocity and polarization. A rotatable retarder can be inserted into the spectrometer beam for measurement of Zeeman splitting and linear polarization in the transition region and chromosphere.

Patent
31 Mar 1980
TL;DR: In this paper, a remote automatic utility reading system includes a reading control center for transmitting commands to and receiving measurement data from remote terminal units via a command responsive control unit, characterized by a computer having a stored program of subroutines, one of which is an interrupt subroutine.
Abstract: A remote automatic utility reading system includes a reading control center for transmitting commands to and receiving measurement data from remote terminal units via a command responsive control unit. The control unit is characterized by a computer having a stored program of subroutines, one of which is an interrupt subroutine. The interrupt subroutine is periodically entered as commands are received by the control unit from the reading control center and directs entry into other ones of the subroutines for execution thereof to effect the simultaneous interlacing of the commands and measurement data being transferred between the reading control center and the remote terminal units.

Journal ArticleDOI
TL;DR: In this paper, the authors employ detailed electronic structure calculations to investigate a model of grain boundary embrittlement, and show that adding sulphur to a cluster of nickel atoms causes strong bonds to be formed between the sulphur atom and the nickel atoms nearest to it, while simultaneously weakening bonds between these nickel atoms and their neighbouring nickel atoms in the cluster.
Abstract: This paper reports the first study employing detailed electronic structure calculations to investigate a model of grain boundary embrittlement. The results show that adding sulphur to a cluster of nickel atoms causes strong bonds to be formed between the sulphur atom and the nickel atoms nearest to it, while simultaneously weakening bonds between these nickel atoms and their neighbouring nickel atoms in the cluster. As a consequence one can suggest that sulphur forms very strong bonds within the plane of the boundary but weakens metal–metal bonds perpendicular to this plane. Although, for the present, the results can be considered only as suggesting one possible embrittling mechanism, they do demonstrate the insight which such calculations can provide into this very central question of grain boundary embrittlement.

Book
Gerald J. Hahn1
01 Jun 1980
TL;DR: In this paper, the tables for normal tolerance limits, sampling plans and screening are presented, as well as a sampling plan for each of the normal tolerance levels and the sampling plans.
Abstract: (1981). Tables for Normal Tolerance Limits, Sampling Plans and Screening. Technometrics: Vol. 23, No. 1, pp. 114-115.

Journal ArticleDOI
V. B. Honsinger1
TL;DR: Two methods are presented by which the performance of ac permanent magnet machines can be predicted using the concept of machine admittance, which defines the shape of the current locus as a function of voltage induced by the magnets.
Abstract: Two methods are presented by which the performance of ac permanent magnet machines can be predicted. The first method utilizes phasor diagrams to include core-loss. The second method uses the concept of machine admittance; this admittance is also adjusted for the effects of core-loss. The admittance also defines the shape of the current locus as a function of voltage induced by the magnets.

Patent
01 May 1980
TL;DR: In this article, a tip cap for a rotor blade which includes at least one radially extending rib having an abrasive coating thereon for providing a close clearance seal between the rotor blade and the surrounding shroud and also for cleaning the shroud of deposits of material thereon.
Abstract: A tip cap for a rotor blade which includes at least one radially extending rib having an abrasive coating thereon for providing a close clearance seal between the rotor blade and the surrounding shroud and also for cleaning the shroud of deposits of material thereon. The tip cap can include a cooling arrangement therein comprising a plurality of cooling passages and a thermal barrier. A method is provided for replacing one tip cap with another and includes the steps of removing a tip cap, machining the end of the rotor blade flat, aligning the replacement tip cap and securing it with the rotor blade.

Journal ArticleDOI
V. B. Honsinger1
TL;DR: In this article, the role of magnet excitation plays in the performance of a permanent magnet motor operating at subsynchronous speeds, as during run-up, is discussed.
Abstract: The permanent magnet motor operating at subsynchronous speeds, as during run-up, is treated with particular emphasis placed on the role that magnet excitation plays. The torque, during run-up, is separated into components called the "cage torque", the "magnet torque" and pulsating components of double-slip-frequency and single-slip-frequency. Equations for calculation of these torques are derived and a comparision of the relative magnitude is given.

Patent
31 Oct 1980
TL;DR: A radially movable carriage with an x-ray source mounted on it is mounted at one end of the U-arm as mentioned in this paper, and means are provided for counterbalancing the source, changer and the intensifier independently.
Abstract: X-ray apparatus for angiography has a support member which is rotatable about a vertical axis and a U-shaped arm mounted on the support for rotating about a horizontal axis. A radially movable carriage with an x-ray source mounted on it is mounted at one end of the U-arm. Carriages which are movable linearly and radially relative to the horizontal axis support an image intensifier and a film changer respectively. The horizontal axis and vertical axis of rotation which is coincident with the x-ray beam axis intersect at a point which is isocentric. Images can be obtained with either the intensifier receptor or film changer receptor in varying degrees of magnification and without magnification while the patient being examined remains coincident with the isocenter. Means are provided for counterbalancing the source, changer and the intensifier independently. Force limited actuators such as motors equipped with slip-clutches are operatively coupled to counterweight cables for driving the carriages and for allowing the carriage to be moved manually. Any carriage has a tendency to remain where it is positioned because of independent counterbalancing and the entire U-arm remains balanced in all of its angular positions and for any position of the receptors or source.