Papers by Keyword: Electric Field

Abstract: This paper presents the behavior of 33kV polymer insulator under nominal voltage and impulse by means of lightning activities. The electrical performance of the insulator is translated to electric field under uniform weather conditions which comprises of air humidity and contamination. ANSYS Maxwell modeling software is used to simulate the structure of the polymer insulator based on the real existing insulator’s dimension. The trend of electric field increase is discussed in detail.

Abstract: In this paper, the characterization of measured electric fields on first return stroke due to lightning channel was studied done. Likewise, previous studies on this case were discussed and reviewed accordingly. Furthermore, the first return stroke was analyzed done in detailed and was indicated on the real measured electric fields. Later the results were discussed appropriately. The behaviorsof first return stroke signal has beencharacterized from previous researchers. This study shows themeasured data in detailed, which include there are slow front time, first return stroke peak, time to peak, zero crossing time and 10% to 90% rise time. The characteristic of first return stroke signal data in Malaysia was compared with data gathered in Sweden. Moreover In addition, the statistical correlation between electric field zero times and corresponding rise times was also been studied.

Abstract: This paper presents the unique characteristics of positive lightning generated vertical electric field waveforms recorded in Malaysia. The focus of the study was the waveforms due to positive lightning and their number of return strokes in a flash. A total of 172 lightning ground flash records were analysed, out of which 57 flashes contained positive lightning with a number of them having high numbers of subsequent return strokes which is somewhat unusual with observations elsewhere. The field measurements were done by using a parallel plate antenna coupled with a recording system. In contrary to the majority of positive lightning return strokes that has been recorded previously, where the average multiplicity is one, this study showed an average multiplicity of 3.86 which is almost four times higher than that is usually observed.

Abstract: This paper presents a characteristic of lightning electric fields. The lightning electric fields were captured by two parallel plats sensor and the characterization for preliminary breakdown pulse (PBP) was studied. A total of 207 data were recorded and 10 data are selected and been utilized in this paper accordingly. In PBP signal data, time before return stroke, ending time and maximum peak of PBP were analyzed. The time duration between the PBP and the occurrence of return stroke was obtained as 0.64 ms and 4.05 ms and then compared with results from other researchers.

Abstract: A molecular dynamics simulation is conducted to describe the behaviour of sodium and chloride ions as they enter a synthetic ion channel (mounted in a bilayer membrane) from aqueous NaCl solutions on either side of the membrane. The channel consists of an α-helical peptide chain scaffold with six aligned crown ether (CE) rings (18-CE-6) as side groups, forming a molecular chamber between each neighbouring pair. Responding to the channel’s axial −2 to −1 V electric potential, the Na⁺ ions, but not Cl⁻, enter the channel spontaneously but they do not proceed beyond the first chamber formed between CE rings 1 and 2. The application of an axial electric field promotes the entry of a Na⁺ ion and its migration over the internal length of the channel. The forces that drive the migration phenomena are predominantly coulombic. Although the same electric field simultaneously allows a Cl⁻ ion initially to access the channel the ion is subsequently expelled from the first chamber into the bilayer. Although a Na⁺ ion may make a facile or even spontaneous entry to the channel it requires an energy estimated from Coulomb forces as ~5 eV to pass subsequent CE rings, and considerably more to exit the channel. An important role is found for the vibrational activity of the ether rings’ C-O-C units in their facilitating contribution to the migration of Na⁺ in the channel.

Abstract: Among particle detectors, particle detectors based on the wide gap semiconductor materials are many used in the nuclear area. For the reliable uses in hard and severe environment, the 4H-SiC is mainly used to the realization of nuclear detector components. This is a part of the topic of the I_SMART European project which proposes to study the nuclear detection of the thermal and fast neutron and gamma rays. In this paper, we deal with the Monte Carlo simulation results of interactions between particles and 4H-SiC detector. In particular, simulation works present the results between fast neutron and 4H-SiC sensor with a comparison between the simulation and experimental results. This article tries to point out the effect of the space charge region depletion, in particular the electric field on the signal response strength.

Abstract: Solid-phase chemical reaction speed control is one of the most essential problems of physics and chemistry of solid bodies. Special attention is paid to the studies of sensitivity and stability of explosive substances (ES). Fundamental issues of studies of azides of heavy metals (AHM) are connected with developing ways of controlling new chemical reactions – solid-phase chain reactions in which electron excitations of a crystal lattice serve as active particles. Applied value is determined by safety issues of ES that include such wide range of problems as storage, transfer, destruction, etc.The result of this work is the use of the experimental results for purposeful change of energetic material

Abstract: Organic CHNO-containing high energy density materials have been widely used for storing large amounts of the chemical energies which can be rapidly transformed into heat upon various external perturbations during detonation. The sensitivity of the energetic materials is subjected to considerable concern for safety and maintenance. Periodic density functional theory with the all-electron basis sets were employed in this work to unravel the impact, friction, and electric-fields induced decomposition of HMX. The minimum energy paths for the N−NO₂ homolysis reactions of HMX in the bulk and gas phases were obtained. The surface-enhanced effect on the decomposition of HMX were calculated for both (010) and (100) surfaces. A general theoretical scheme has been proposed to assess the intrinsic mechanic and electrostatic sensitivities of the pure energetic materials.

Abstract: A method to optimize the structure parameters of sheds has been put forward for transmission line composite insulator. Fist of all, the unbounded domain is simulated by far field element to handle the open boundary problem of the insulator electric field model. Then, the finite element method (FEM) is employed to calculate the electrical field. The influence of sheds radius on composite insulator electric filed distribution is analyzed. The sheds radius is selected as optimization variable, and the optimization objective is to make the electric field more uniform. Moreover, the parameter analysis method is employed, and the optimal solution of the sheds radius is obtained. The optimized sheds radius make the electric field range and gradient along the insulator surface both tend to the minimum.

Abstract: The aim of the study is to demonstrate that separation of solvated ions in solution of mixed salts under the action of external periodic electric field is caused by the formation of clusters consisting of solvent molecules and surrounding the ions. Such clusters have the dimensions of about 0.1 µm. The study includes the theoretical estimation of cluster dimensions and experimental determination of the external electric field frequency that gives rise to the separation of solvated ions. The results testify that placing the volume distributed electric charge of ion into dielectric liquid is accompanied by the formation of supramolecular particles. We called such particles “clusters”. The linear dimensions of clusters significantly exceed the first and the second radii of solvation (approximately 1 Angstrom) and amount to nearly 0.1 µm. At such sizes, inertial properties of clusters and their natural frequencies may allow controlling their movement by applying an external electric field to solution.