scholarly journals Restraining Surface Charge Accumulation and Enhancing Surface Flashover Voltage through Dielectric Coating

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 750
Author(s):  
Jixing Sun ◽  
Sibo Song ◽  
Xiyu Li ◽  
Yunlong Lv ◽  
Jiayi Ren ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Electric Field ◽  
Electric Fields ◽  
Transition Process ◽  
Metallic Particle ◽  
Particle Charging ◽  
Insulating Surfaces ◽  
Surface Flashover ◽  
Charging Time ◽  
The Impact

A conductive metallic particle in a gas-insulated metal-enclosed system can charge through conduction or induction and move between electrodes or on insulating surfaces, which may lead to breakdown and flashover. The charge on the metallic particle and the charging time vary depending on the spatial electric field intensity, the particle shape, and the electrode surface coating. The charged metallic particle can move between the electrodes under the influence of the spatial electric field, and it can discharge and become electrically conductive when colliding with the electrodes, thus changing its charge. This process and its factors are mainly affected by the coating condition of the colliding electrode. In addition, the interface characteristics affect the particle when it is near the insulator. The charge transition process also changes due to the electric field strength and the particle charging state. This paper explores the impact of the coating material on particle charging characteristics, movement, and discharge. Particle charging, movement, and charge transfer in DC, AC, and superimposed electric fields are summarized. Furthermore, the effects of conductive particles on discharge characteristics are compared between coated and bare electrodes. The reviewed studies demonstrate that the coating can effectively reduce particle charge and thus the probability of discharge. The presented research results can provide theoretical support and data for studying charge transfer theory and design optimization in a gas-insulated system.

The dependence of the rate of electrochemical charge transfer on the electric field at the metal-electrolyte interface

1972 ◽  
Vol 25 (2) ◽  
pp. 231 ◽  
Author(s):  
DB Matthews
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Potential Energy ◽  
Electric Field ◽  
Electric Fields ◽  
Potential Energy Curves ◽  
Energy Curve ◽  
Electrolyte Interface ◽  
Activated State ◽  
Wide Range

Electric fields at the metal-electrolyte interface are very high (of the order of 107 V/cm) and one intuitively expects that these fields should have a profound influence on the movement of charged species such as ions and electrons at the interface. Qualitatively, such field effects manifest themselves as deviations from linearity of Tafel plots or as a dependence of the symmetry factor on electrode potential. It is shown that Gurney's potential energy curve representation of charge transfer reactions yields only small changes in β over a wide range of potential, with the anharmonic (Morse) curves showing smaller changes than the harmonic (parabolic) curves. Superposition of the double layer electric field on these potential energy curves increases the curvature of the Tafel plots, but the effect is still not very large, being within the limits of uncertainty in determining the correct form of the potential energy curves. The effect of electric field on electron transfer is considered both from the viewpoint of change in electron transfer distance arising from a dependence of coordinates of the activated state on potential and from the viewpoint of a direct effect on the electron transfer barrier (analogous to field electron emission). The field emission effects are found to be even less than the effects of the field on the proton transfer potential energy barrier.

Two-phase GaAs cermet-gate charge-coupled devices

1991 ◽  
Vol 69 (3-4) ◽  
pp. 224-228
Author(s):  
M. LeNoble ◽  
J. V. Cresswell ◽  
R. R. Johnson
Keyword(s):  
Charge Transfer ◽  
Electric Field ◽  
Electric Fields ◽  
Two Phase ◽  
Charge Coupled Device ◽  
Charge Coupled Devices ◽  
Band Limited ◽  
Gate Charge

A nonplanar 64-pixel, 2-phase GaAs cermet-gate charge-coupled device (CMCCD) and a planar 128-pixel, 2-phase GaAs CMCCD are described. The former device employs a castellation to provide the "built-in" electric field for controlling the flow of signal charge within the channel, whereas, the latter device uses externally applied electric fields to achieve this control. Both devices have been operated at 46 MHz, demonstrating charge transfer efficiencies of 0.996 and in excess of 0.999, respectively. The application of the planar 2-phase GaAs CMCCD in a 500 or 7.81 MHz transient digitizer module for acquisition and transfer of dc to 250 MHz band-limited signals will also be presented.

Tuning the inter-molecular charge transfer, second-order nonlinear optical and absorption spectra properties of a π-dimer under an external electric field

2017 ◽  
Vol 19 (47) ◽  
pp. 31958-31964 ◽  
Author(s):  
Feng-Wei Gao ◽  
Hong-liang Xu ◽  
Zhong-Min Su
Keyword(s):  
Charge Transfer ◽  
Electric Field ◽  
Electric Fields ◽  
Nonlinear Optical ◽  
Stability Control ◽  
External Electric Fields ◽  
Optical Responses ◽  
Molecular Charge ◽  
Spectra Properties ◽  
The Stability

Different strengths of external electric fields enhance the stability, control the inter-molecular charge transfer and strengthen the nonlinear optical responses of a π-dimer.

scholarly journals Numerical Calculation of Electric Fields in Housing Spaces Due to Electromagnetic Radiation from Antennas for Mobile Communication

10.14311/478 ◽  
2003 ◽  
Vol 43 (5) ◽  
Author(s):  
H.-P. Geromiller ◽  
A. Farschtschi
Keyword(s):  
Electromagnetic Wave ◽  
Electric Field ◽  
Electromagnetic Radiation ◽  
Electric Fields ◽  
Mobile Communication ◽  
Signal Frequency ◽  
High Signal ◽  
Maximum Value ◽  
Mobile Antennas ◽  
The Impact

The influence of electromagnetic radiation from mobile antennas on humans is under discussion in va'rious groups ofscientists, This paper deals with the impact ofelectromagnetic radiation in a housing space. The space is assumedto be bordered by 5 walls of ferroconcrete and a door-window combination on the 6th side, the latter to be electromagnetically transparent. The transparent side of the housing is exposed to an electromagnetic wave. As the source ofradiation is considered to be far away from the housing, the radiation is regarded to be from a plane wave. Due to the high signal frequency and ferroconcrete walls, 5 sides ofthe housing space are considered to be perfect conductors. The electric field inside the housing is calculated numerically by the method of finite differences for different angles of incidence of the radiated electromagnetic wave. The maximum value of the calculated electric field is outlined in a diagram.

scholarly journals Impact of disturbance electric fields in the evening on prereversal vertical drift and spread F developments in the equatorial ionosphere

2018 ◽  
Vol 36 (2) ◽  
pp. 609-620 ◽  
Author(s):  
Mangalathayil A. Abdu ◽  
Paulo A. B. Nogueira ◽  
Angela M. Santos ◽  
Jonas R. de Souza ◽  
Inez S. Batista ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Plasma Bubble ◽  
Large Variability ◽  
Plasma Drift ◽  
F Region ◽  
Vertical Drift ◽  
Spread F ◽  
The Impact ◽  
Magnetic Disturbances

Abstract. Equatorial plasma bubble/spread F irregularity occurrence can present large variability depending upon the intensity of the evening prereversal enhancement in the zonal electric field (PRE), that is, the F region vertical plasma drift, which basically drives the post-sunset irregularity development. Forcing from magnetospheric disturbances is an important source of modification and variability in the PRE vertical drift and of the associated bubble development. Although the roles of magnetospheric disturbance time penetration electric fields in the bubble irregularity development have been studied in the literature, many details regarding the nature of the interaction between the penetration electric fields and the PRE vertical drift still lack our understanding. In this paper we have analyzed data on F layer heights and vertical drifts obtained from digisondes operated in Brazil to investigate the connection between magnetic disturbances occurring during and preceding sunset and the consequent variabilities in the PRE vertical drift and associated equatorial spread F (ESF) development. The impact of the prompt penetration under-shielding eastward electric field and that of the over-shielding, and disturbance dynamo, westward electric field on the evolution of the evening PRE vertical drift and thereby on the ESF development are briefly examined. Keywords. Ionosphere (ionospheric irregularities)

Effectiveness of Pulsed Electric Fields in Controlling Microbial Growth in Milk

2008 ◽  
Vol 4 (7) ◽  
Author(s):  
Adedayo Otunola ◽  
Ayman El-Hag ◽  
Shesha Jayaram ◽  
William A Anderson
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Milk Fat ◽  
Indigenous Population ◽  
Inoculum Size ◽  
Microbial Inactivation ◽  
Log Reduction ◽  
The Impact

A study was conducted to assess the effectiveness of pulsed electric field (PEF) inactivation of a heterogeneous community of microbes. The aim was to assess the impact of process parameters on an indigenous population of microbes present in milk, rather than pure cultures used in other studies. Tests over an electric field strength range of 10 – 40 kV/cm and 10 to 120 pulses per millilitre showed that high electric field strength and pulse number inactivated microbes by up to approximately 2 log. Inoculum size affected PEF effectiveness when only a few pulses were applied. A significant log-reduction was achieved against the indigenous microbes found in milk that were apparently recalcitrant to commercial pasteurization. Microbial inactivation was more extensive when E. coli was not added to the indigenous population, indicating that the added pure culture was more resistant than the indigenous microbes. The milk fat content had a significant negative effect on the extent of log-reduction for indigenous microbes, when 2% and 18% levels were compared.

Optical properties of nematic liquid crystal (C21H27NO2S) under AC/DC electric fields

2009 ◽  
Vol 87 (4) ◽  
pp. 293-298 ◽  
Author(s):  
Mehriban Emek ◽  
Nurettin Besli ◽  
Ahmet Yildirim ◽  
Suleyman Yilmaz
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Electric Field ◽  
Domain Structure ◽  
Nematic Liquid Crystal ◽  
Electric Fields ◽  
Transition Process ◽  
Optical Methods ◽  
Rotational Angle ◽  
Dc Electric Fields

In this study, the effects of the phase transition on the optical transmittance of the nematic liquid crystal C21H27NO2S, 4′-isothiocyanatophenyl-4-pentylbicyclo[2,2,2]octane-1-carboxylate are investigated in terms of temperature variation and rotational angle of the polarizer through electro-optical methods under AC / DC electric fields. It is observed that the domain structure of the material is affected considerably by the applied electric field as the temperature changes. Under applied electric fields, the crystal-nematic (CN) phase-transition point changes and the behaviour of the liquid crystal in the phase-transition region shows some differences. The intensity of the light passing through the system under a DC electric field increases as the electric field rises. Nevertheless, the intensity of the transmitted light under an AC electric field increases at the beginning and then decreases as the electric field rises to a temperature of more than 355 K. These results can be explained through the formation of a domain structure during the phase-transition process and the light scattering caused by these structures.

scholarly journals Comparative Analysis of the Various Generalized Ohm's Law Terms in Magnetosheath Turbulence as Observed by Magnetospheric Multiscale

2021 ◽  
Author(s):  
Julia Stawarz ◽  
Lorenzo Matteini ◽  
Tulasi Parashar ◽  
Luca Franci ◽  
Jonathan Eastwood ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Electron Mass ◽  
Turbulent Fluctuation ◽  
Electron Pressure ◽  
Ohm’S Law ◽  
Magnetospheric Multiscale ◽  
Ohm's Law ◽  
Turbulent Plasmas ◽  
The Impact

<p><span>Electric fields (<strong>E</strong>) play a fundamental role in facilitating the exchange of energy between the electromagnetic fields and the changed particles within a plasma. </span>Decomposing <strong>E</strong> into the contributions from the different terms in generalized Ohm's law, therefore, provides key insight into both the nonlinear and dissipative dynamics across the full range of scales within a plasma. Using the unique, high‐resolution, multi‐spacecraft measurements of three intervals in Earth's magnetosheath from the Magnetospheric Multiscale mission, the influence of the magnetohydrodynamic, Hall, electron pressure, and electron inertia terms from Ohm's law, as well as the impact of a finite electron mass, on the turbulent electric field<strong> </strong>spectrum are examined observationally for the first time. The magnetohydrodynamic, Hall, and electron pressure terms are the dominant contributions to <strong>E</strong> over the accessible length scales, which extend to scales smaller than the electron gyroradius at the greatest extent, with the Hall and electron pressure terms dominating at sub‐ion scales. The strength of the non‐ideal electron pressure contribution is stronger than expected from linear kinetic Alfvén waves and a partial anti‐alignment with the Hall electric field is present, linked to the relative importance of electron diamagnetic currents within the turbulence. The relative contributions of linear and nonlinear electric fields scale with the turbulent fluctuation amplitude, with nonlinear contributions playing the dominant role in shaping <strong>E</strong> for the intervals examined in this study. Overall, the sum of the Ohm's law terms and measured <strong>E</strong> agree to within ∼ 20% across the observable scales. The results both confirm a number of general expectations about the behavior of <strong>E</strong> within turbulent plasmas, as well as highlight additional features that may help to disentangle the complex dynamics of turbulent plasmas and should be explored further theoretically.</p>

Bubble Formation and Detachment Under the Influence of Electric Fields and the Role of Gravity

2005 ◽  
Author(s):  
C. Herman ◽  
Z. Liu ◽  
E. Iacona
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Heated Surface ◽  
Gravity Level ◽  
Reduced Gravity ◽  
Bubble Behavior ◽  
Transfer Coefficients ◽  
High Heat Transfer ◽  
The Impact ◽  
Bubble Removal

Boiling is an attractive solution to cooling problems in aerospace engineering because of the high heat transfer coefficients associated with phase change processes. Bubble detachment from an orifice shows some resemblance to bubble departure in boiling. The buoyancy force is responsible for bubble removal from the surface in terrestrial conditions. In space, with the gravity level being orders of magnitude smaller than on earth, bubbles formed during boiling can remain attached to the surface. As a result, the amount of heat removed from the heated surface can decrease, and it is difficult to predict reliably and accurately. The impact of electric fields is investigated with the aim to control bubble behavior and help bubble removal from the surface on which they form in reduced gravity. The behavior of single gas bubbles injected through an orifice into an electrically insulating liquid is studied in reduced gravity under the influence of static electric fields and the results of the experiments are compared with data obtained using a simplified model. The bubble life cycle was visualized in terrestrial conditions and reduced gravity. Bubble departure, volume and dimensions at detachment were measured and analyzed for different parameters such as gravity level, electric field magnitude and electric field uniformity. Results suggest that these parameters significantly affect bubble behavior, shape, volume and dimensions at detachment.

scholarly journals Role of hydrogen bond alternation and charge transfer states in photoactivation of the Orange Carotenoid Protein

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Igor A. Yaroshevich ◽  
Eugene G. Maksimov ◽  
Nikolai N. Sluchanko ◽  
Dmitry V. Zlenko ◽  
Alexey V. Stepanov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Electric Field ◽  
Quantum Chemical ◽  
Time Resolved ◽  
Bond Alternation ◽  
Orange Carotenoid Protein ◽  
The Impact

AbstractHere, we propose a possible photoactivation mechanism of a 35-kDa blue light-triggered photoreceptor, the Orange Carotenoid Protein (OCP), suggesting that the reaction involves the transient formation of a protonated ketocarotenoid (oxocarbenium cation) state. Taking advantage of engineering an OCP variant carrying the Y201W mutation, which shows superior spectroscopic and structural properties, it is shown that the presence of Trp201 augments the impact of one critical H-bond between the ketocarotenoid and the protein. This confers an unprecedented homogeneity of the dark-adapted OCP state and substantially increases the yield of the excited photoproduct S*, which is important for the productive photocycle to proceed. A 1.37 Å crystal structure of OCP Y201W combined with femtosecond time-resolved absorption spectroscopy, kinetic analysis, and deconvolution of the spectral intermediates, as well as extensive quantum chemical calculations incorporating the effect of the local electric field, highlighted the role of charge-transfer states during OCP photoconversion.

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