Materials Literature
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The NOVICE code is used by a number of government and aerospace organizations for radiation analysis of space systems. Generality of three dimensional modeling, with graphics output, is a major code capability. Major analysis methods are ray-trace/sectoring for rapid engineering design and Monte Carlo for design verif…
The history of electrical insulation from its origins to the present is briefly reviewed. In the 1800s the development of electrical apparatus made necessary the use of a variety of insulating materials to meet increasingly demanding needs. Up to about 1925 only naturally occurring products such as asphalt, rubber, mi…
It is pointed out that reliable HVDC insulation design has to take into account the fact that electric field distributions are different from AC distributions due to resistivities of the materials. Additionally, polarity reversals and transients result in field distributions different from steady state AC and DC field…
Abstract Liquid–liquid thermally induced phase separation of the polymer‐diluent system of poly(ethylene‐ co ‐vinyl alcohol) (EVOH)‐glycerol was examined under light scattering. For EVOH with an ethylene content of 38 mol % (EVOH38), maxima of the scattered light intensity were observed that indicated that phase separ…
In order to synthesize a peripherally rigid dendritic donor-acceptor dyad for energy transfer studies, a tritolan dendron based on a tetraphenylmethane scaffold was prepared from New Fuchsin. The dendron showed a small degree of homoconjugation but a large hypochromic effect. Coupling of two such dendrons with an anth…
A mechanism of degradation in polymeric insulation at fields lower than required for hot-electron transport is shown. Cable grade low-density polyethylene was aged under divergent and uniform fields, using needle-plane and dimple-plane geometries, respectively. It is shown that, at points of electric stress enhancemen…
To overcome the viewing-angle dependence of TN (twisted nematic) cells, the author has investigated two-domain TN (TDTN) and two-domain tilted homeotropic (TDTH) cells with optical compensation for active matrix applications. The simulated and experimental results for TDTN show a large viewing zone of +or-40 degrees i…
Compressed SF/sub 6/ gas is the main high-voltage insulation medium in gas insulated equipment. Recent progress in studies of high-voltage breakdown in uniform, quasi-uniform, and nonuniform field systems is described. This includes time lags to breakdown, the effect of particle contamination, and the flashover of ins…
Colossal Magnetoresistive p-n Junctions of Te-Doped LaMnO3/Nb-doped SrTiO3, LÜ Hui-Bin, Dai Shou-Yu, Chen Zheng-Hao, Liu Li-feng, Guo Hai-Zhong, Xiang Wen-Feng, Fei Yi-Yan, He Meng, Zhou Yue-Liang, Yang Guo-Zhen
Deals with the response of the actuator using shape memory alloy (SMA). The SMA actuator was developed for a robot. This study aims at the development of the position control system; control parameters are set automatically for the SMA actuator drives any kind of load. The SMA actuator in this study is box type actuat…
The authors present a variety of surface-drive film actuators and discuss their characteristics. An actuator consisting of a stator with three-phase 420 mu m-pitched electrodes and a slightly conductive slider was developed previously. A finer 100 mu m-pitched stator was fabricated and operated. A two-phase stator, wh…
Describes an experimental study on pattern recognition of a partial discharge (PD) in a cross-linked polyethylene (XLPE) cable by using a neural network (NN) system. The NN adopted was a three-layer artificial neural system with feedforward connections, and its learning method was a back-propagation algorithm incorpor…
Abstract Quantitative analysis of the formation energy of Cr vacancy in MgCr 2 O 4 was made by first principles calculation. A 56‐atom supercell was employed and relaxation of atoms within the second‐nearest‐neighbor shell of the vacancy was taken into account. The formation energy was calculated as a function of the…
A micropolarizer of nickel nanowire arrays within an anodic alumina membrane (AAM) was fabricated by anodization of pure Al and electrodeposition of Ni, respectively. X-ray diffraction, scanning electron microscopy and transmission-electron microscopy reveal that the nanowires are polycrystal and have an average diame…
The influence of accumulated charges on a polymer insulated surface on the 50% lightning impulse (1.2-50 mu s) has been investigated. The 50% flashover voltage was measured for three different conditions: under dry environment, immediately after immersing the upper shed and body of the insulator in saline water, and i…
A novel method for producing electrets is proposed in which an electric discharge is induced by a negative impulse voltage in a small air gap. The dielectric foil to be charged is placed between two planar electrodes, being in contact with one of them and separated from the other by the air gap. The electric discharge…
An investigation is described of the applicability of Fourier series/integral methods as printed circuit board thermal analyzers. The limitations of a totally uniform heat transfer coefficient for the board surfaces are shown to be somewhat compensated for by using lumped-parameter thermal resistances as board heat re…
High-vacuum beam transport tubes are being designed for use in an accelerator under development at Los Alamos. In areas such as weld-heat-affected zones, the tubes will require localized magnetic permeability of less than 1.02. Seven austenitic stainless steel candidates, 304L, 310, 316L, 317LN, 20Cb-3, Nitronic 33, a…
The main objective of this paper is to derive a simple, engineering model for a NiTi-based shape memory alloy (SMA) that can be used as a first-step, inexpensive computational tool in designing components including SMAs. The model is based on a Reuss approximation in which the stress in every grain is considered the s…
Techniques for calculating overheating effects of GIC (geomagnetically induced currents) on large shell-form transformers are described. The techniques include the method of calculating the exciting current and its harmonic content under DC injection in the transformer neutral; three dimensional magnetic flux calculat…