Materials Literature
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Electrical breakdown at the interface of two dielectric surfaces is a major design consideration in underground cable accessories. The reliability of any given system essentially depends on its performance in aging. Several factors could affect the aging performance of a dielectric interface. The interfacial pressure…
The lyotropic behavior of three mixed valence diruthenium(II,III) alkoxybenzoates in dodecane mixtures has been analyzed. The studied compounds, namely, Ru 2 (3,4,5-B3OC14) 4 Cl [1] (3,4,5 - B3OC14 = 3,4,5 - tri( n -tetradecyloxy)benzoate), Ru 2 (3,4 - B2OC14) 4 Cl [2] (3,4 - B2OC14 = 3,4 - di( n -tetradecyloxy)benzoa…
For a growing number of customers, the transient thermal response of packaged semiconductor devices is a critical issue. It is not enough to predict "time averaged" junction temperatures based on average power dissipation, because the actual duty cycle and associated transient response of a device may lead to peak jun…
Synchronous motor drives are well suited for rolling mill applications, where good performance is required both at zero and high speed in field weakening. Direct torque control (DTC) sets high dynamic requirement for the excitation control too. DTC controls only the stator flux linkage and stator current is determined…
This paper presents a method based on both Artificial Neural Networks (ANNs) and on a multidimensional optimisation procedure in order to significantly reduce the time taken and to improve the accuracy in evaluating parameters of the Jiles-Atherton's model of magnetic hysteresis. The main steps of the method can be in…
The partial discharge behaviour of the insulation between power electronic devices, e.g. IGBT's (Insulated Gate Bipolar Transistors), and its heat sink has been investigated. In conventional IGBT packages this insulation consists of a ceramic layer which is metallized on both sides embedded in silicon gel. Voids at th…
Under certain assumptions, similar models can be applied for rectifiers and devices with electric arc characteristic. The analysis considers single and three-phase uncontrolled rectifiers with continuous and discontinuous evolution of the AC current. It leads to four possible situations which fit with the harmonic beh…
Carbon (fiber)-carbon (matrix) composites have the highest thermal conductivity per unit density among materials suitable for thermal management applications. C-C composites also have high toughness and their mechanical strength increases with temperature. We have developed C-C materials and structures for heat manage…
Tin phosphate glasses, of general formula x SnO · (1 − x )P 2 O 5 (0.3 < x < 0.8), have been prepared by conventional melt-quench techniques and their structures studied using 31 P and 119 Sn nuclear magnetic resonance. The distribution of [PO 4 ] Q n species changes with composition in accordance with the simple bina…
The application of interleaving techniques is a very common practice in the construction of transformers for electronic circuits, in order to reduce the AC resistance and leakage inductance. However, the effects of the interleaving techniques on the capacitive effects is not so well known. This work presents a study o…
The study of the biological consequences of oxidative damage to DNA requires the characterization of DNA lesions at a molecular level. The oxidation of guanine in the dinucleoside monophosphate, d(GpT), by a metal-oxo porphyrin produces a dehydro-guanidinohydantoin derivative. The (1)H NMR spectrum of this oxidized gu…
Degradation of XLPE cable by water trees gives rise to harmonics in the loss current. The authors are engaged in development of diagnostic methods for water tree degradation utilizing these harmonic components. As a result of this development, the following was discovered. The harmonic components occurring in the loss…
This paper describes deterioration phenomena and mechanisms on silicone rubber housings of the polymer insulators by corona discharges. The corona discharge was observed on the trunk portion the insulator tested in a fog chamber. Nitric acid and ozone generated by the corona discharge were recognized on that trunk por…
Theoretical electronic structure studies on the anionic and neutral ${\mathrm{Al}}_{13}X$ $(X=\mathrm{Li}--\mathrm{Cs})$ clusters have been carried out using a gradient corrected density-functional approach. The alkali atoms occupy the hollow sites on the ${\mathrm{Al}}_{13}$ icosahedron surface and the calculated ver…
The mutual solubilities and liquid–liquid equilibria of acetonitrile binary systems with different compounds exhaustively and critically are reviewed. The compounds include water, inorganic compounds, and a variety of organic compounds (hydrocarbons, halogenated hydrocarbons, alcohols, carboxylic acids and esters, nit…
During the last twenty years many papers have been presented on the subject of aging of silicone rubber under conditions of high voltage, outdoor environment and contamination. Many opinions on the aging mechanisms of silicone rubber have been published. This paper will review current and previous works which have add…
This paper analyses scale effects for actuator types which are strong candidates for micro-actuation: shape memory alloys (SMAs), electrostatic, electromagnetic and piezoelectric actuators. SMA actuators are studied in detail and compared to the other actuator types on a basis of force, response time, and power densit…
We report the synthesis, electronic properties, and second-order nonlinear optical (NLO) response of asymmetric heteronuclear push−pull bimetallic complexes with pyrazine (pyz) and trans -1,2-bis(4-pyridyl)ethylene (BPE) as polarizable linkers, connecting the “W(CO) 5 ” fragment (acting as donor group) and “ cis -Rh(C…
Molecular dynamics (MD) simulations are undertaken on a series of five copolyimides based on two different dianhydrides: the flexible 4,4‘-oxydiphthalic dianhydride (ODPA) and the rigid bulky bicyclo(2.2.2)-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BCDA). The diamines are respectively 4,4‘-oxydi(phenylamine) (ODA…
beta-[SiW(12)O(40)](4)(-) (C(3)(v) symmetry) is sufficiently higher in energy than its alpha-isomer analogue that effectively complete conversion to alpha-[SiW(12)O(40)](4)(-) (T(d)) is observed. By contrast, beta- and alpha-[AlW(12)O(40)](5)(-) (beta- and alpha-1; C(3)(v) and T(d), respectively) are sufficiently clos…