Showing papers by "General Electric published in 1979"

The Thermal Conductivity of Nonmetallic Crystals

Abstract: Publisher Summary This chapter reviews the thermal conductivity of nonmetallic crystals at temperatures comparable to or higher than the Debye temperature. It deals with the intrinsic behavior of such pure crystals at high temperatures. In such crystals, the dominant carriers of thermal energy are phonons and the dominant scattering mechanism to be considered is the intrinsic phonon–phonon scattering. This is a small section of the much larger problem of the thermal conductivity of nonmetallic solids and clearly it neglects possible heat transport by photons, charge carriers, polarons, and magnons. It also neglects other possible phonon scattering mechanisms such as isotopes, impurities, vacancies, charge carriers, dislocations, grain boundaries, and crystal boundaries. It presents the absolute value of the thermal conductivity, K, as determined by phonon–phonon scattering, the temperature dependence of K, the volume dependence of K, the change in K upon melting, and the minimum value of K. The chapter discusses a composite curve for the thermal conductivity versus temperature of pure KCl measured at a constant pressure of, say, one atmosphere.

Matrix Structural Analysis

Abstract: Examines computerized structural analysis methods for buildings, bridges, and other structures, with special emphasis on current practices. Covers the stiffness analysis of frames, the flexibility method, virtual work principles, special analysis procedures, and more. Defines the terminology, coordinate systems, and fundamental concepts of structural behavior, laying the foundation for the study of more advanced treatments such as the finite element method.

Measuring the Psychological Complexity of Software Maintenance Tasks with the Halstead and McCabe Metrics

Abstract: Three software complexity measures (Halstead's E, McCabe's u(G), and the length as measured by number of statements) were compared to programmer performance on two software maintenance tasks. In an experiment on understanding, length and u(G) correlated with the percent of statements correctly recalled. In an experiment on modification, most significant correlations were obtained with metrics computed on modified rather than unmodified code. All three metrics correlated with both the accuracy of the modification and the time to completion. Relationships in both experiments occurred primarily in unstructured rather than structured code, and in code with no comments. The metrics were also most predictive of performance for less experienced programmers. Thus, these metrics appear to assess psychological complexity primarily where programming practices do not provide assistance in understanding the code.

Photoinitiated cationic polymerization with triarylsulfonium salts

Abstract: Triarylsulfonium salts Ar3S+MXn− with complex metal halide anions such as BF4−, AsF6−, PF6−, and SbF6− are a new class of highly efficient photoinitiators for cationic polymerization. In this article we describe several synthetic routes to the preparation of these compounds along with their physical and spectroscopic properties. Mechanistic studies have shown that when these compounds are irradiated at wavelengths of 190–365 nm carbon-sulfur bond cleavage occurs to form radical fragments. At the same time the strong Brϕnsted acid HMXn, which is the active initiator of cationic polymerization that takes place in subsequent “dark” steps, is also produced. A study of the parameters that affect the photolysis of triarylsulfonium salts is reported with a measurement of the absolute quantum yields. The cationic polymerizations of four typical monomers—styrene oxide, cyclohexene oxide, tetrahydrofuran, and 2-chloroethyl vinyl ether—with triarylsulfonium salt photoinitiators are described.

Compact of boron-doped diamond and method for making same

Abstract: In one embodiment, a compact for tools, such as cutting, drilling, wire drawing and shaping tools, consists essentially of a porous mass of self-bonded, boron-doped diamond particles and a catalyst-solvent material. The method for making such a compact comprises the steps of bonding a mass of boron-doped diamond particles, aided by a catalyst-solvent material, under high temperatures and high pressures (HP/HT). In another embodiment, a composite compact, which is made in a similar manner to the first embodiment, consists essentially of (i) a layer of a porous mass of self-bonded, boron-doped diamond particles and catalyst-solvent material; and (ii) a substrate layer of cemented carbide bonded to the diamond layer.

A calorimetric study of acrylate photopolymerization

Abstract: The kinetics of the photoinitiated polymerization of lauryl acrylate (LA), 1,6-hexanedioldiacrylate (HDDA) and pentaerythritol tetraacrylate (PET4A) have been investigated using differential scanning calorimetry (DSC). An autoacceleration phenomenon is observed with the multifunctional acrylates, but not with lauryl acrylate. The empirical dependences of reaction rate on such parameters as incident light intensity, initiator concentration, and temperature have been established and are in general found to vary with monomer conversion. Apparent activation energies for the photopolymerizations have been determined from rate versus temperature data. The multifunctional acrylates show an increasing activation energy with monomer conversion, whereas the apparent activation energy for lauryl acrylate not only decreases with conversion, but becomes negative at conversions greater than about 30%. The ratio kp/k is calculated from rate versus conversion data under constant illumination and the (independently determined) initiation rate. Analysis of rate versus time data under nonsteady-state conditions (light turned off) yields the ratio kt/kp. With these two ratios the rate constants for propagation (kp) and termination (kt) may be separated and their respective values calculated. Both kp and kt are found to decrease substantially with monomer conversion, indicating a significant change in the rates of both the propagation and termination steps as the polymerization advances. These observations are explained in terms of a radical isolation phenomenon and diffusion control of the propagation step.

Capacitive touch entry apparatus having high degree of personal safety

Abstract: A capacitive touch entry structure utilizes an array of at least one capacitive touch sensor fabricated upon a double-sided printed circuit board adhesively mounted upon a surface of a transparent insulative substrate. The substrate has sufficient thickness to safely insulate user personnel, contacting the substrate surface furthest from an electrode of the capacitive touch sensor, from electrical potentials present adjacent to the panel surface upon which the capacitive touch sensor is fastened. Touch sensor circuitry and interconnections may be advantageously fabricated directly upon the pair of conductive planes, sandwiching an insulative layer therebetween, to form the printed circuit portion of the structure. A conductive guard may also be disposed adjacent to the substrate to shield at least the lead portions of the touch sensors from capacitive effects.

Studies on Crack Initiation and Stable Crack Growth

Abstract: Experimental results are presented which suggest that parameters based on the J-integral and the crack opening tip displacement δ are viable characterizations of crack initiation and stable crack growth. Observations based on some theoretical studies and finite-element investigations of the extending crack revealed that J and δ when appropriately employed do indeed characterize the near-field deformation. In particular, the analytical and experimental studies show that crack initiation is characterizable by the critical value of J or 6, and stable crack growth is characterizable in terms of the J or δ resistance curves. The crack opening angle, d6/da, appears to be relatively constant over a significant range of crack growth. Thus, appropriate measures of the material toughness associated with initiation are J I c and δ I c , and measures of material toughness associated with stable crack growth are given by the dimensionless parameters T J [= (E/σ o 2 )(dJ/da)] and T δ [= (E/σ o )(dδ/da)]. The two-parameter characterization of fracture behavior by J I c and T J or δ I c and T δ is analogous to the characterization of deformation behavior by the yield stress and strain hardening exponent.

Magnetic properties of amorphous Fe x B 1 0 0 − x ( 72 x 8 6 ) and crystalline Fe 3 B

Abstract: Amorphous samples of ${\mathrm{Fe}}_{x}{\mathrm{B}}_{100\ensuremath{-}x}(72l~xl~86)$ have been studied by $^{57}\mathrm{Fe}$ M\"ossbauer spectroscopy and in some cases by magnetization measurements. The magnetic ordering temperature (${T}_{C}$) decreases sharply with increasing Fe concentration; from 760 K (${\mathrm{Fe}}_{72}$${\mathrm{B}}_{28}$) to 552 K (${\mathrm{Fe}}_{86}$${\mathrm{B}}_{14}$). The value of ${T}_{C}$ of amorphous pure Fe has been extrapolated to about 220 K. Well-defined hyperfine field distributions ${P(H)}$ have been found. The mean hyperfine field is found to be proportional to the average Fe moment with a ratio of about 130 kOe/${\mathrm{\ensuremath{\mu}}}_{\mathrm{B}}$. The shape of $P(H)$ for each alloy is practically independent of temperature. At low temperatures, the effective hyperfine field (${H}_{\mathrm{eff}}$) shows a temperature dependence of ${H}_{\mathrm{eff}}(T)={H}_{\mathrm{eff}}(0)(1\ensuremath{-}B{T}^{\frac{3}{2}}\ensuremath{\cdots})$ due to spin-wave excitations. The value of ${B}_{\frac{3}{2}}=B{({T}_{C})}^{\frac{3}{2}}$ increases with Fe concentration. As the Fe concentration is increased in these alloys, the reduced hyperfine field decreases faster with reduced temperature due to a systematic change in the distribution of exchange interactions. A correlation of ${H}_{\mathrm{eff}}(0)$ and the isomer shift exists for crystalline and amorphous Fe-B systems. Crystalline ${\mathrm{Fe}}_{3}$B(${T}_{C}\ensuremath{\sim}800$ K) has been found after crystallizing amorphous samples with $xg75$ under high heating rates. At $Tl{T}_{C}$, ${\mathrm{Fe}}_{3}$B shows at least three magnetically inequivalent sites, whereas at $Tg{T}_{C}$, electric quadrupole interactions are observed. The crystal structure of ${\mathrm{Fe}}_{3}$B is likely to be tetragonal rather than orthorhombic.

A Simple Method for Regression Analysis With Censored Data

Abstract: Problems requiring regression analysis of censored data arise frequently in practice. For example, in accelerated testing one wishes to relate stress and average time to failure from data including unfailed units, i.e., censored observations. Maximum likelihood is one method for obtaining the desired estimates; in this paper, we propose an alternative approach. An initial least squares fit is obtained treating the censored values as failures. Then, based upon this initial fit, the expected failure time for each censored observation is estimated. These estimates are then used, instead of the censoring times, to obtain a revised least squares fit and new expected failure times are estimated for the censored values. These are then used in a further least squares fit. The procedure is iterated until convergence is achieved. This method is simpler to implement and explain to non-statisticians than maximum likelihood and appears to have good statistical and convergence properties. The method is illustrated by a...

Ultraviolet curable epoxy silicone coating compositions

Abstract: Epoxy functional diorganosiloxane fluids are combined with bis-aryl iodonium salts, particularly linear alkylate bis-dodecylphenyl iodonium salts to form a silicone coating composition effective for rendering surfaces non-adherent to other surfaces which would normally adhere thereto, and which will cure to a final non-adherent state upon brief exposure to ultraviolet radiation. Adhesion of the silicone coating to a substrate can be improved with the addition of β-(3,4-epoxycyclohexyl)ethyltrimethoxy silane.

Differential geared engine

Abstract: A gas turbine engine comprising a fan, a compressor and a turbine, wherein the torque requirements of the fan or compressor can be modulated, is provided with differential gearing to transmit all of the fan and compressor power requirements from the turbine. The differential gearing maintains an adjustable speed relationship between the fan and compressor with respect to the turbine depending upon the torque requirements thereof and the gear ratios within the differential gearing.

Capacitive touch control and display

Abstract: A control for use upon a solid panel, devoid of control shaft apertures, allows data entry by rotational positioning of a human member, such as one's finger, about a pattern of a plurality of interdigitated electrodes formed upon an interior surface of the panel. The position of the member varies the capacitance between adjacent ones of the electrodes, with position-decoding electronics energizing successive ones of the plurality of electrodes with successive phases of a master signal and recovering information relating the phase of the signal returned from the control to the position of the member. A light-emitting display may be positioned behind the panel to indicate the index of the control knob by a variable-length circular bar of light, a digitized display and the like.

Low cost bipolar current collector-separator for electrochemical cells

Abstract: A bipolar current collector-separator for electrochemical cells consists of a molded aggregate of electro-conductive graphite and a thermoplastic fluoropolymer combined in a weight ratio of 2.5:1 to 16:1. The bulk resistivity of such a molded bipolar current collector-separator is less than 4×10 -3 ohm inches (Ω in.). It has excellent corrosion resistance to a variety of feedstocks such as brine, aqueous HCl, etc. and to various electrolysis products such as caustic, chlorine, hydrogen, etc. In one alternative form the anodic side of a current collector-separator for a water electrolyzer is covered by a thin layer of a passivated metallic foil thus protecting the graphite current collector against attack by oxygen.

Solid state relay

Abstract: A solid state relay having a light-emitting diode, an array of series connected photodiodes and a field effect transistor is described

Fast Ionic Transport in Solids

Abstract: The discovery of inorganic solids with ionic conductivities comparable to those of aqueous electrolytes has revolutionized solid-state electrochemistry. Sodium beta alumina, a Na+ conductor, and LixTiS2, an intercalation compound with simultaneous Li+ and electronic conductivity, are two of the best and most versatile fast ionic conductors. A wide variety of cations can replace Na+ in beta alumina and Li+ in LixTiS2 and change the properties of the materials. Sodium beta alumina and LixTiS2 are currently used in the development of high-energy density batteries for electric vehicles and electrical utility load leveling. Current research in solid ionic conductors is exploring new intercalation compounds, solid polymer electrolytes, and alkali ion and proton transport in crystalline solids.

Multiple Layer Series Connected Winding Design for Minimum Losses

Abstract: The classical one dimensional magnetic field and eddy current distribution ("proximity effect") within a series connected multiple layer coil is reexamined with regard to power losses withinthe windings. When the lengthand number of layers ina coilare fixed, the power dissipation within each layer can be minimized by choosing a specific radial thickness for each layer. Above or below this thickness, the losses within the winding increase. The conductor thickness which results in minimum dissipation depends on the relative position of the layer. When compared to a design having a constant thickness for each layer (chosen for minimum total dissipation), it is found that substantial savings in power consumption can be realized by employing a variable thickness of conductor. The one dimensional solution in cylindrical coordinates for the eddy current and skin effect in amultiple layer series connected coil is alsopresented. By solving the problem n cylindrical coordinates, the effect of curvature on the power consumption within each layer is apparent. This analysis should have application to the design of power transformers, armature windings, and inductors for power transmission lines.

Testing Thirteen Attitude Scales for Agreement and Brand Discrimination

Abstract: This article describes a study in which 630 women rated brands of package goods on each of 13 popular scales and compares the ratings to find which scales were related and which discriminated best ...

Dual frequency horn antenna system

Abstract: A feature of this invention is the provision of an antenna system providing two, coaxial, copolarized, independently focused beams: a relatively wide, low frequency, searching beam, and a relatively narrow, high frequency, tracking beam; and comprising a dual frequency, dual polarization feedhorn; a polarization dependent subreflector; a concave polarization reversing reflector; a concave polarization twisting reflector; and a planar frequency dependent dielectric lens.

Fluid flow control system

Abstract: A fluid flow control system for controlling the flow of fluid through a valve is disclosed. The control system controls the flow of fluid through the valve by varying the position of the valve. The control system performs this function in such a manner that the change in position of the valve at all times remains sufficiently bounded so as to ensure that the actual flow of fluid through the valve is substantially equal to the flow predicted by the static flow equation for the valve.

Modified polyester compositions.

Abstract: Modified thermoplastic polyester compositions which comprise (a) a poly-(1,4-butylene terephthalate) resin or polyester copolymer and, optionally, a poly (ethylene terephthalate) resin and (b) a modifier therefor comprising a combination of a polyacrylate resin and an aromatic polycarbonate, and, optionally (c) filler and/or reinforcing agent and/or (d) a name retardant. Modifier (b) provides enhanced resistance to impact fracture, increased strength and improved resistance to heat distortion in articles molded from the compositions.

Modern Coding Practices and Programmer Performance

Abstract: The late 70' s find structured programming increasingly popular—this and other techniques are programming's future. But what does experimental evaluation say about their actual effects on programmer performance?

Formation and magnetic properties of Fe-B-Si amorphous alloys

Abstract: The magnetic properties and crystallization temperatures of alloys in the ternary Fe-B-Si system are reported. The Curie temperature increases slightly on replacement of boron by silicon. This results in a sharp ridge of relatively constant room-temperature saturation magnetization extending from Fe 80 B 20 to Fe 82 B 12 Si 6 . The coercivity exhibits a broad minimum, both before and after stress relief annealing, in the region around Fe 81 B 15 Si 4 and extending at least to Fe 77 B 13 Si 10 . The crystallization temperature increases with increasing silicon and with decreasing iron and boron. The alloys with silicon are generally easier to prepare in the amorphous state than the binary Fe-B alloys. Thus for the highest saturation magnetization alloy combined with ease of preparation, stability, and lowest losses, the alloys between Fe 81 B 17 Si 2 and Fe 82 B 12 Si 6 are preferred.

Electronic voting system

Abstract: An electronic voting system includes a plurality of wireless response units, each response unit capable of transmitting several different digitally coded signals. Each of these digitally coded signals corresponds to the response of a person responding to a given stimulus. Each response unit transmits a selected digitally coded response via a radio frequency signal during one of a series of time intervals, a different time interval corresponding to each of the response units. An interrogating and response processing unit signals the response units to commence response transmission and receives, processes and displays the transmitted responses for observation by selected persons.

Measurement of true blood velocity by an ultrasound system

Abstract: Two components of the velocity of blood or similar liquids and the true flow vector are derived by a linear transducer array cross-beam configuration. Ultrasound pulses are transmitted from the center elements and backscattered echoes are received by left and right receiver sub-arrays whose locations depend on the observation point. A duplex imaging system with a sector scanner incorporates a Doppler modality with little added complexity and provides components of flow velocity parallel to and transverse to the acoustic beam direction from which the true velocity vector is computed.

Hydrogen assisted cracking of type 304 stainless steel

Abstract: This paper reports a study of hydrogen assisted cracking in type 304 stainless steel. It shows that the most detrimental effect in increasing the susceptibility of the material to hydrogen cracking is the formation of martensite upon deformation. This is particularly damaging if the martensite is localized at the grain boundaries. With martensite present intergranular impurities such as phosphorus play a secondary role. As martensite becomes more difficult to form, the importance of impurities increases.

Circuit breaker accessories packaged in a standardized molded case

Abstract: Various circuit breaker accessories, such as a shunt trip, an undervoltage release, an auxiliary switch, and a bell alarm, are individually packaged in a standardized molded insulative accessory case for ultimate factory or even field installation in a molded case, automatic power circuit breaker.