Comparison of Cable Insulation Control in Weak and Strong Electric Fields

2015 ◽  
Vol 756 ◽  
pp. 486-490 ◽  
Author(s):  
Nadezda S. Starikova ◽  
Vitaly V. Redko ◽  
G.V. Vavilova
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Strong Electric Field ◽  
Weak Electric Field ◽  
Cable Insulation ◽  
Modern Methods ◽  
Insulation Thickness ◽  
Defect Dimension ◽  
Cylindrical Capacitor ◽  
Strong Electric Fields

In this paper the modern methods of cable products insulation control are referred. A comparison of efficiency of the cable insulation defects control by changing in cable area capacitance is carried out in the strong and weak electric fields. The electric cable can be represented as a cylindrical capacitor, but to simplify the issue the insulation area is represented as a plate capacitor with anisotropic dielectric. The cable insulation model is created in the software Comsol Multyphysic. The effect of the defect dimension on the cable area electric capacitance in a strong and weak electric field is described. Also, the control sensitivity of both methods was assessed and compared with each other. The control sensitivity in a weak electric field is slightly higher for the defects with small size (less than 70% from insulation thickness). The control sensitivity in a strong electric field is considerably higher for the defects with big size (more than 70% from insulation thickness).

scholarly journals Generation of sequences of strong electric monopulses in nitride films

2021 ◽  
Vol 34 (2) ◽  
pp. 187-201
Author(s):  
Volodymyr Grimalsky ◽  
Svetlana Koshevaya ◽  
Jesus Escobedo-Alatorre ◽  
Anatoliy Kotsarenko
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Strong Electric Field ◽  
Numerical Algorithms ◽  
Negative Differential Conductivity ◽  
Differential Conductivity ◽  
Threshold Values ◽  
Bias Electric Field ◽  
Bulk Semiconductors ◽  
Strong Electric Fields

This paper presents theoretical investigation of the excitation of the sequences of strong nonlinear monopulses of space charge waves from input small envelope pulses with microwave carrier frequencies due to the negative differential conductivity in n-GaN and n-InN films. The stable numerical algorithms have been used for nonlinear 3D simulations. The sequences of the monopulses of the strong electric field of 3 - 10 ps durations each can be excited. The bias electric field should be chosen slightly higher than the threshold values for observing the negative differential conductivity. The doping levels should be moderate 1016 -1017 cm-3in the films of ? 2 mm thicknesses. The input microwave carrier frequencies of the exciting pulses of small amplitudes are up to 30 GHz in n-GaN films, whereas in n-InN films they are lower, up to 20 GHz. The sequences of the electric monopulses of high peak values are excited both in the uniform nitride films and in films with non-uniform conductivity. These nonlinear monopulses in the films differ from the domains of strong electric fields in the bulk semiconductors. In the films with non-uniform doping the nonlinear pulses are excited due to the inhomogeneity of the electric field near the input end of the film and the output nonlinear pulses are rather domains.

scholarly journals Spontaneous generation of spin current from the vacuum by strong electric fields

2019 ◽  
Vol 2019 (11) ◽  
Author(s):  
Xu-Guang Huang ◽  
Mamoru Matsuo ◽  
Hidetoshi Taya
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Strong Electric Field ◽  
Spin Current ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Longitudinal Direction ◽  
Spontaneous Generation ◽  
Strong Electric Fields ◽  
Schwinger Mechanism

Abstract We discuss spontaneous spin current generation from the vacuum by strong electric fields as a result of interplay between the Schwinger mechanism and a spin–orbit coupling. By considering a homogeneous slow strong electric field superimposed by a fast weak transverse electric field, we explicitly evaluate the vacuum expectation value of a spin current (the Bargmann–Wigner spin current) by numerically solving the Dirac equation. We show that a non-vanishing spin current polarized in the direction perpendicular to the electric fields flows mostly in the longitudinal direction. We also find that a relativistic effect due to helicity conservation affects the direction/polarization of a spin current.

scholarly journals Origin of the enhanced structural and reorientational relaxation rates in the presence of relatively weak dc electric fields

2004 ◽  
Vol 76 (1) ◽  
pp. 215-221 ◽  
Author(s):  
A. Vegiri
Keyword(s):  
Molecular Dynamics ◽  
Electric Field ◽  
Electric Fields ◽  
Structural Relaxation ◽  
Structural Changes ◽  
Common Mechanism ◽  
Weak Electric Field ◽  
Water Molecules ◽  
Relaxation Rates ◽  
Dynamics Simulations

The origin of the dramatic increase of the reorientational and structural relaxation rates of single water molecules in clusters of size N = 16, 32, and 64 at T = 200 K, under the influence of an external, relatively weak electric field (~0.5 107 V/cm) is examined through molecular dynamics simulations. The observed effect is attributed not to any profound structural changes, but to the increase of the size of the molecular cage. The response of water to an electric field in this range shows many similarities with the dynamics of water under low pressure. By referring to simulations and experiments from the literature, we show that in both cases the observed effects are dictated by a common mechanism.

The elongated shape of a dielectric drop deformed by a strong electric field

2010 ◽  
Vol 664 ◽  
pp. 286-296 ◽  
Author(s):  
DOV RHODES ◽  
EHUD YARIV
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Strong Electric Field ◽  
Outer Region ◽  
Spherical Shape ◽  
Problem Formulation ◽  
Boundary Integral ◽  
Uniform Electric Field ◽  
Cross Sectional ◽  
Drop Shape

A dielectric drop is suspended within a dielectric liquid and is exposed to a uniform electric field. Due to polarization forces, the drop deforms from its initial spherical shape, becoming prolate in the field direction. At strong electric fields, the drop elongates significantly, becoming long and slender. For moderate ratios of the permittivities of the drop and surrounding liquid, the drop ends remain rounded. The slender limit was originally analysed by Sherwood (J. Phys. A, vol. 24, 1991, p. 4047) using a singularity representation of the electric field. Here, we revisit it using matched asymptotic expansions. The electric field within the drop is continued into a comparable solution in the ‘inner’ region, at the drop cross-sectional scale, which is itself matched into the singularity representation in the ‘outer’ region, at the drop longitudinal scale. The expansion parameter of the problem is the elongated drop slenderness. In contrast to familiar slender-body analysis, this parameter is not provided by the problem formulation, and must be found throughout the course of the solution. The drop aspect-ratio scaling, with the 6/7-power of the electric field, is identical to that found by Sherwood (J. Phys. A, vol. 24, 1991, p. 4047). The predicted drop shape is compared with the boundary-integral solutions of Sherwood (J. Fluid Mech., vol. 188, 1988, p. 133). While the agreement is better than that found by Sherwood (J. Phys. A, vol. 24, 1991, p. 4047), the weak logarithmic decay of the error terms still hinders an accurate calculation. We obtain the leading-order correction to the drop shape, improving the asymptotic approximation.

Electrorheology

MRS Bulletin ◽  
1991 ◽  
Vol 16 (8) ◽  
pp. 38-43 ◽  
Author(s):  
Therese C. Jordan ◽  
Montgomery T. Shaw
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
High Speed ◽  
Flow Properties ◽  
Electric Field Effects ◽  
Properties Of Materials ◽  
Strong Electric Fields ◽  
Silica Suspensions ◽  
Type Of Behavior ◽  
Damping Systems

The influence of electric fields on the deformation and flow properties of materials has been a subject of interest for many years. Recently, there has been renewed interest in a particular branch of these electric field effects—the electrorheological (ER) effect. The ER effect is also known as the Winslow effect after its founder Willis Winslow. Winslow observed that applying strong electric fields to nonaqueous silica suspensions activated with a small amount of water caused rapid solidification of the originally fluid material. This type of behavior was seen as instrumental in the development of high-speed valves, reactive damping systems, and a host of other applications.

Numerical modeling of cathode-directed streamers branching in strong electric fields

2016 ◽  
Author(s):  
Белогловский ◽  
Andrey Beloglovskiy ◽  
Федорова ◽  
A. Fedorova
Keyword(s):  
Numerical Modeling ◽  
Numerical Model ◽  
Electric Fields ◽  
Strong Field ◽  
Strong Electric Field ◽  
Three Dimensional ◽  
Strong Electric Fields ◽  
Electron Avalanches ◽  
Discharge Gap ◽  
Positive Streamer

A research of conditions of the branching of positive streamer in air in a strong electric field by the use a three-dimensional numerical model is presented. This model is based on the assumption that the development of large electron avalanches in the strong field in front of the streamer head leads to branching. Tendency for branching has been observed, if the ratio of the diameters of the streamer heads to the distance between them is not greater than 0.55. If this ratio is more than 0,55, merger of originally formed streamer heads has been observed, and then only one streamer develops in the discharge gap.

scholarly journals IS QFT WITH EXTERNAL BACKGROUNDS A CONSISTENT MODEL?

2011 ◽  
Vol 03 ◽  
pp. 58-64
Author(s):  
S. P. GAVRILOV ◽  
D. M. GITMAN
Keyword(s):  
Dirac Equation ◽  
Electric Field ◽  
Electric Fields ◽  
Strong Electric Field ◽  
Coulomb Field ◽  
Back Reaction ◽  
Consistent Model

We discuss consistency of the concept of external background in QFT. Different restrictions on magnitude of magnetic and electric fields are analyzed. The back reaction due to strong electric field is calculated and restrictions on the magnitude and duration of such a field are obtained. The problem of consistency of Dirac equation with a superstrong Coulomb field is discussed.

Line Patterning with Microparticles at Different Positions in a Single Device Based on Negative Dielectrophoresis

2013 ◽  
Vol 25 (4) ◽  
pp. 650-656 ◽  
Author(s):  
Tomoyuki Yasukawa ◽  
◽  
Yusuke Yoshida ◽  
Hironobu Hatanaka ◽  
Fumio Mizutani
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Indium Tin Oxide ◽  
Strong Electric Field ◽  
Electric Signal ◽  
Electric Field Line ◽  
Peak Voltage ◽  
Ac Electric Field ◽  
Fluidic Device ◽  
Line Patterns

We report on control of line pattern positioning with particles fabricated by negative dielectrophoresis (n-DEP) using the applied intensity and phase of an AC electric field. Line patterns were fabricated in a microfluidic device consisting of upper conductive indium-tin-oxide (ITO) substrates and lower ITOinterdigitated microband array (IDA) electrodes used as the template. A 6-µm-diameter polystyrene particles suspension was introduced into the device between upper ITO and the bottom ITO-IDA substrate. An AC electric signal of a typically 20 peak-to-peak voltage and 1.0 MHz was then applied to upper ITO and bands on lower IDA, resulting in the formation of line patterns with low electric-field gradient regions. AC voltage was applied to bands A and B on lower IDA with the opposite phase and the same frequency and intensity. When the signal identical to band A was applied to upper ITO, particles were aligned above band A because relatively lower electric fields were produced in these regions. In contrast, the application of a signal identical to band B formed line patterns with particles aligned above band B due to the generation of a strong electric field between band A and upper ITO and the disappearance of the strong electric field between band B and upper ITO. The decrease in applied intensity to upper ITO shifted the accumulated position of particles to the center between bands A and B because of the balance of electric fields generated between band A or B and upper ITO. We thus fabricated line patterns with particles at desired positions in the fluidic device.

Pool-Frenkel effect and high frequency dielectric constant determination of semiconducting P2O5-Li2MoO4-Li2O and P2O5-Na2MoO4-Na2O bulk glasses

Open Physics ◽  
2008 ◽  
Vol 6 (2) ◽  
Author(s):  
Dariush Souri ◽  
Mohammad Elahi ◽  
Mohammad Yazdanpanah
Keyword(s):  
Dielectric Constant ◽  
Electric Field ◽  
Electric Fields ◽  
Threshold Voltage ◽  
High Frequency ◽  
Strong Electric Field ◽  
Nonlinear Effects ◽  
High Frequency Dielectric Constant ◽  
Conduction State ◽  
Current Voltage

AbstractThe ternary 70P2O5-10Li2MoO4-20Li2O and 70P2O5-10Na2MoO4-20Na2O glasses, prepared by the press-melt quenching technique, were studied at temperatures between 298 and 418 K for their high dc electric field properties. For the above purpose, the effect of a strong electric field on the dc conduction of these amorphous bulk samples was investigated using the gap-type electrode configuration. At low electric fields, the current-voltage (I — V) characteristics have a linear shape, while at high electric fields (> 103 V/cm), bulk samples show nonlinear effects (nonohmic conduction). Current-voltage curves show increasing departure from Ohm’s law with increasing current density, leading to critical phenomena at a maximum voltage (threshold voltage), known as switching (switch from a low-conduction state to a higher-conduction state at threshold voltage). The Pool-Frenkel high-field effect was observed at electrical fields of about 103–104 V/cm; then the lowering factor of the potential barrier, the high frequency dielectric constant, and the refractive index of these glasses were determined.

Calculation of the transverse conductivity for electrons interacting with waves in strong electric fields

1968 ◽  
Vol 46 (23) ◽  
pp. 2659-2661 ◽  
Author(s):  
Harold N. Spector
Keyword(s):  
Distribution Function ◽  
Electric Field ◽  
Electric Fields ◽  
Optical Lattice ◽  
Transverse Electric ◽  
Lattice Vibrations ◽  
Transverse Electric Fields ◽  
Transverse Conductivity ◽  
Strong Electric Fields ◽  
The Waves

We have obtained the transverse a.c. conductivity for electrons interacting with waves in the presence of strong d.c. electric fields. The presence of the d.c. electric field leads to the introduction of a drifted distribution function for the electrons and a complex, field-dependent temperature. The expression for the transverse a.c. conductivity can be used to find the effects of the electric field on the propagation and absorption of waves in solids which induce transverse electric fields. We have applied our results to the interaction of electrons with transverse optical lattice vibrations and find that for all values of ql, it is the drifted distribution function which leads to the amplification of the waves.

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