Showing papers by "General Electric published in 1972"

Electric Energy Systems Theory: An Introduction

Abstract: This text is intended for undergraduate seniors or first-year graduate students in the power systems field. In this second edition the introductory chapters have been strengthened to improve appeal to students, and new problems and material has been added on system protection.

Optical and bonding model for non-crystalline SiOx and SiOxNy materials

Abstract: Optical data for non-crystalline SiOx materials are presented and analyzed for the energy region 1 to 26 eV. The results indicate that amorphous substances of all intermediate compositions between Si and SiO2 can be formed and that these materials are not simple mixtures of particles of Si and SiO2 but rather the two atom species are blended on an atomic scale. The basic units of this structure are Si tetrahedra (perhaps highly distorted) of the type Si(SiyO4−y) in which the distribution of atoms for all y = 0 to 4 is statistical for any given atom ratio. Further it is found that the optical properties of these layers are determined by the presence and grouping of SiSi and SiO bonds and that clusters of like bonds of the dimension of a Si(Si4) or Si(O4) tetrahedra have optical properties comparable to those exhibited by amorphous silicon or quartz respectively “in bulk”.

Surface crosslinking of polyethylene using a hydrogen glow discharge

Abstract: Linear high-density polyethylene is crosslinked by exposing it to a hydrogen glow discharge and alternatively by exposing it to a low-pressure Hg–A ultraviolet lamp in a dry nitrogen atmosphere. For the UV lamp case, the crosslinked gel is measured as a function of the radiation dose. For the plasma case, the crosslinked gel is measured as a function of the exposure time. The two gelation curves are alternatively compared to an exponentially attenuated light theory and a diffusion theory. Excellent agreement exists between the measured gel-versus-dose curve and the theoretical curve based on the light theory for a monochromatic light beam at 1849 A. The gelation curve for the hydrogen glow discharge case can be explained using the identical theory but applied to a spectrum of light covering the range from 1200 A to 1900 A. The different curves can be explained in terms of the different spectra. Energy transfer between the plasma and the polymer due to excited atoms, and/or charged particles, is not required to account for the different gel curves.

Grain Growth in Very Porous Al2O3 Compacts

Abstract: Extensive grain growth was observed by scanning electron microscopy in very porous Al2O3 compacts, even at densities <40% of theoretical After ∼7% shrinkage at 1700°C, the grain size increased from ∼03 to 051 μm in a compact having a relative green density of 031 During grain growth in highly porous compacts, the grains appear initially to be chainlike, then to be oblong, and finally to be equiaxed The proposed mechanism of initial grain growth involves the filling of necks between adjacent grains followed by the movement of the grain boundary through the smaller grain Although grain growth in very porous compacts is quite different from coalescence and ordinary grain growth, the kinetics are similar

Genetic Basis of the Biodegradation of Salicylate in Pseudomonas

Abstract: The genetic basis of the biodegradation of salicylate in Pseudomonas putida R1 has been studied This strain utilizes the meta pathway for oxidizing salicylate through formation of catechol and 2-hydroxymuconic semialdehyde The enzymes of the meta pathway are induced by salicylate but not by catechol, and the genes specifying these enzymes are clustered The gene cluster can be eliminated from some salicylate-positive cells by treatment with mitomycin C and appears to exist inside the cell as an extrachromosomal element This extrachromosomal gene cluster, termed the SAL plasmid, can be transferred by conjugation from P putida R1 to a variety of other Pseudomonas species

Combustion chamber construction

Abstract: A combustion chamber for use in gas turbine engines is provided with a liner formed of a high temperature material. The liner includes a plurality of panels of the material mounted by means of a slideable friction mounting arrangement upon a high strength structural frame. As a result of this mounting arrangement, the liner is substantially isolated from structural forces associated with the combustion chamber, while the frame is substantially isolated from thermal stresses associated with the liner. Means are provided for positioning and securing individual liner panels in the circumferential, axial, and radial directions with respect to the frame as well as circumferentially with respect to other liner panels. The individual liner panels may be easily removed for repair or replacement without disassembling the frame and associated components. For the purpose of cooling, a cooling fluid is passed into a plenum to cool the radially outward side of the panels by convection. Means are also provided for directing the same fluid from the plenum to the liner inner surfaces in a cooling film.

Direct bonding of metals with a metal-gas eutectic

Abstract: A method is described for direct bonding of metallic members to other metallic members with a metal-gas eutectic. The method comprises placing a metal member such as copper, for example, in contact with another metal member, such as nickel, for example, heating the metal members to a temperature slightly below the melting point of the lower melting point metal, e.g., approximately 1,072*C. for copper, the heating being performed in a reactive atmosphere, such as an oxidizing atmosphere, for a sufficient time to create a metal-gas eutectic melt which, upon cooling, bonds the metal members together. Various metals and reactive gases are described for direct bonding.

Thermal Conductivity of II-VI Compounds and Phonon Scattering by Fe 2 + Impurities

Abstract: The thermal conductivities $\ensuremath{\kappa}$ of over twenty different single crystals of synthetic ZnO, ZnS, ZnSe, ZnTe, CdTe, and of natural, cubic ZnS have been measured from temperatures of 3 to 300 K The results for the undoped crystals above 30 K can be scaled using the parameter $\overline{M}\ensuremath{\delta}{\ensuremath{\Theta}}^{3}$, where $\overline{M}$, $\ensuremath{\delta}$, and $\ensuremath{\Theta}$ are the average mass, interatomic spacing, and Debye temperature, respectively A comparison of these results with those in the literature for BeO, CdS, CdSe, HgSe, HgTe, Si, Ge, GaAs, and InSb show that the same scaling parameter applies for most of them The compounds HgSe and HgTe exhibit anomalously low $\ensuremath{\kappa}$ values Crystals doped with ${\mathrm{Fe}}^{2+}$ show a resonant-type one-phonon scattering from the five low-lying energy levels of this $3{d}^{6}$ ion Group theory shows that the strongest scattering occurs for phonons of energy $2\ensuremath{\Delta}$, where $\ensuremath{\Delta}$ is the interlevel spacing of the ${\mathrm{Fe}}^{2+}$ ion

Moiré Gauging of In-Plane Displacement Using Double Aperture Imaging

Abstract: An easily implemented method of measuring in-plane surface displacement by photographing an object through two laterally displaced apertures is described and the experimental results are presented. The displacement is displayed as a pattern of moire fringes over the image. No previously constructed grids or rulings are required as in normal moire devices. The method is noncontacting and requires no special surface preparation. The sensitivity is easily adjusted and is shown to be equivalent to that obtained using double-exposure holography or speckle pattern interferometry techniques. The method has potential application in mechanically unstable environments or where the conditions are such that grids or strain gauges cannot be attached to the object.

Optimum Snubbers for Power Semiconductors

Abstract: It is generally necessary to connect an RC snubber across a power rectifier or thyristor to absorb the energy associated with the recovery current of the device and limit the resulting voltage spike and rate of rise dv/dt. For a given snubber capacitance, it is shown that there is an optimum damping resistance which minimizes the peak voltage, but a lower resistance is required to minimize the average dv/dt to the peak. Design procedures are derived for selecting the capacitance and optimum resistance to limit the peak voltage or dv/dt to specified values. The device recovery current is trapped in circuit inductance, and its energy must be dissipated, while the snubber produces additional losses as the price of performing its limiting function.

Sulfonated polyxylylene oxide as a permselective membrane for water vapor transport

Abstract: Sulfonated polyxylylene oxide membranes are very effective for the separation of water vapor from other gases. Such a gas separation is very selective and may be readily accomplished at atmospheric pressure. Membrane devices for humidifying or drying an air stream are described.

4,4'-Isopropylidene-bis(3- and 4-phenyleneoxyphthalic anhydride)

Abstract: Aryloxy dianhydrides are prepared from the hydrolysis of the reaction product of a nitro-substituted phenyl dinitrile with a metal salt of a dihydroxy aryl compound in the presence of a dipolar aprotic solvent.

Electronic module using flexible printed circuit board with heat sink means

Abstract: An electronic circuit component having particular utility in multi-layer circuit board construction formed essentially of a flexible dielectric sheet of material used as the board base to which is attached circuit runs etched from copper sheets clad to the dielectric sheet prior to etching. Generally, circuitry runs are separated according to alignment with either the X or Y axis with the runs on each side of the dielectric sheet being parallel to only one of those axes. Integration of communication between X and Y runs is by means of plated through holes to which circuit elements may be attached. Flatpack integrated circuits are attached to the board oriented with their covers toward and their heat sink base portions away from the board. By placing all flatpacks on one side of the flexible board structure and looping the structure back on itself, a high circuit component density can be achieved with the heat sink portions of flatpacks exposed exteriorly of the loops of the structure facilitating placing the flatpacks in heat conducting contact with a casing.

The effect of high vacuum on the low cycle fatigue law

Abstract: Push-pull fatigue tests have been conducted on several materials at various frequencies and temperatures in air and high vacuum (10−8 torr) and the fatigue life determined in terms of the cyclic plastic strain. In contrast to a changing exponent of the Coffin-Manson law with increasing temperature in air, in high vacuum this exponent is found to remain nearly constant at a value of about 0.5. Further, the temperature sensitivity of this exponent and of life at a specific plastic strain range in high vacuum is slight. Pronounced plastic instability (specimen shortening and fattening) was observed for the ductile metals investigated and crack nucleation was retarded. In all cases crack propagation was transgranular in vacuum. It is concluded that for the materials, temperature, and frequencies investigated, the degradation of fatigue life at elevated temperature is due to environmental enhancement of intergranular fracture. Materials investigated include A286 at room temperature and 593°C, nickel A at 550°C, 304 stainless steel at 816°C and 7075T6 aluminum alloy.

Rotating electrical machine having rotor and stator cooled by means of heat pipes

Abstract: A polyphase induction motor having a rotor and a stator, each having heat pipes incorporated therein, is disclosed. The stator is comprised of a stack of laminations having radial slots therein which contain heat pipes as well as electrical conductors. The stator heat pipes are located in the stator slots and extend axially to a remote location beyond the stator and the rotor. The stator heat pipes contain wicks and contain a twophase fluid coolant. The rotor is also comprised of a stack of laminations with radial slots located in the outer periphery thereof. Heat pipes are incorporated in the rotor slots and, like the heat pipes in the stator slots, extend axially to a remote location beyond the rotor and the stator. The rotor heat pipes also serve as electrical conductors as well as heat exchangers for cooling the rotor. Thus, all of the rotor heat pipes are electrically interconnected by end rings located at the axial extremities of the rotor. The rotor heat pipes also contain a two-phase fluid coolant. However, because centrifugal force promotes condensate return within the rotor heat pipes wicks need not be used in the rotor heat pipes. Cooling fins are provided on those sections (condenser sections) of the heat pipes which extend axially beyond the rotor and the stator thereby forming air heat exchangers. Moreover, the fins on the moving rotor heat pipes act as moving fan blades and, being located proximate to the cooling fins on the stator heat pipes, effectively form a single-pass, forced-convection, air heat exchanger.

Low level currents in insulated gate field effect transistors

Abstract: A theory for low-level current operation in Insulated Gate Field Effect Transistors is developed. Using the depletion approximation for the semiconductor surface potential, an analytical expression is obtained which is accurate for gate voltages corresponding to surface operation from depletion to the onset of strong inversion. Numerical calculations that avoid the limitations on gate voltage have shown the theory to hold as well for surface potentials corresponding to strong inversion.

Combined thrust reversing and throat varying mechanism for a gas turbine engine

Abstract: A thrust reversing mechanism for reversing the flow through either the exhaust nozzle or fan duct of a jet propulsion powerplant is further modified to include apparatus for varying the throat area of the exhaust nozzle or fan duct as a means of optimizing powerplant efficiency throughout its operating range.

Graphical Analysis of Accelerated Life Test Data with the Inverse Power Law Model

Abstract: In this paper, graphical methods are presented for analyzing accelerated life test data with the inverse power law model, when all test units are run to failure. The inverse power law model is described, and graphical methods for estimating its parameters from such complete data are given. These methods are illustrated with accelerated test data on time to breakdown of an insulating fluid. While the methods are presented with the inverse power law model, they can be used for analyzing many other accelerated life test situations. These methods are presented so that they can be used by individuals with a limited statistical background.

Cardiac pacemaker rate/interval computer system

Abstract: Information signals taken directly from an implanted pacemaker or remotely by way of a telephone circuit are furnished to a computer which processes the information and displays it in digital form in terms of the pacemaker''s stimulus pulse rate or, alternatively, in terms of the interval between pulses. The existing rate or interval is compared with prior measurements and is used to determine the pacemaker''s residual battery life.

Thermo-optical and differential scanning calorimetric observations of mobility transitions in polystyrene-poly(2,6-dimethyl-1,4-phenylene oxide) blends

Abstract: Transition temperatures by thermo-optical analysis (TOA) and by DSC were measured on films of polystyrene (PS), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO resin) and nine homogeneous blends of these polymers. The TOA procedure consists of automatically monitoring light transmission through birefringent scratches in a film during heating at constant rate in a microscope hot stage between crossed (90°) plane polarizers. The TTOA transition temperature, defined as the temperature of birefringence disappearance in the scratches, increased monotonically from 113°C for pure PS to 222°C for pure PPO resin at a 10°/min heating rate. The Tg (DSC) similarly ranged from 99°C to 212°C at a 20°/min heating rate. The TOA technique as described should be a useful addition to thermomechanical studies of transparent polymers and polymer blends.

Flame retardant thermoplastic compositions

Abstract: Normally flammable polyester resins (a) are rendered flameretardant without loss in toughness by combination with (b) a flame retardant amount of (i) an aromatic carbonate copolymer, from 25 to 75 wt. percent of the repeating units comprising chloro- or bromo-substituted dihydric phenol units; (ii) an aromatic carbonate homopolymer having repeating units comprising chloro- or bromo-substituted dihydric phenol units in combination with an aromatic carbonate homopolymer having repeating dihydric phenol units; or (iii) a combination of (i) with an aromatic carbonate homopolymer having repeating dihydric phenol units, (c) an antimony-containing compound and (d) a reinforcing filler.

Raman Scattering Cross Sections

Abstract: RAMAN scattering of light from molecules has long been interesting as a source of information about molecular structure and as a versatile technique for chemical analyses. The advent of the laser, however, has broadened the usefulness of this method for the quantitative measurement of density (ref. 1, for example) and temperature (ref. 2, for example) and there is now considerable activity in both the basic and applied aspects of this field.

Porous abradable turbine shroud

Abstract: A turbine blade tip-sealing shroud between a rotating bladed turbine and the surrounding casing of a turbojet engine is formed of substantially cylindrical inner and outer layers of porous sintered metal or similar material. The porosity of the radially inner layer is greater than the porosity of the outer layer and is adapted to withstand frictional rubbing contact with the turbine. The outer layer of the shroud is impinged by cooling air for transpiration cooling of the shroud, the amount of cooling air passed therethrough being metered by the porosity of the outer layer. The relative porosities of the two layers enable the shroud to meter the flow of cooling air to maintain this flow in spite of abrasion of the inner layer and the constriction of the pores thereof by the rotating bladed turbine.