Journal of Electrostatics最新文献

Pipeline leakage accidents of dielectric liquid often occurs in chemical industry, while the investigations on flow electrification of leakage pipe are few. In this study, experiments were conducted to measure and analyze the streaming current inside the pipe and the leakage current of the pipe wall in both intact and leak pipes. Two kinds of diesel oil, namely the light heavy diesel oil and heavy diesel oil, were selected as the flowing media. Furthermore, an empirical expression of the space charge density and the streaming current based on the modified velocity equation was proposed. The space charge density distribution obtained from the experimental streaming current was compared with the theoretical values. The results show that the space charge density obtained from experiments by the proposed expression is in good agreement with the theoretical value.

Bromide in treated natural waters is oxidized to toxic bromate with ozone. For the novelty of pulsed corona discharge (PCD) in water treatment, it's potential in bromide transformation needs clarification. Experimental research into bromide-bromate conversion dependent on control parameters, including pulse repetition frequency, pH, Br⁻ concentration, and presence of organics, was undertaken. Bromide transformed to bromate in acidic and circum-neutral media; transformation of bromate to bromide was also observed. Bromide was poorly oxidized in alkaline media. Oxidation of bromide was obstructed with oxalate. Formation of nitrate was noticeably decelerated by bromate.

In the applied electric field, the behavioral characteristic which occurs in particle-particle systems always are used in dielectric insulation, and nanomaterials regulation, among which is the key to correctly compute the electric field. Because the dipole model without fully considering the particle interactions so that has defects in computing in some cases. This study introduced the mutual-coupling dipole offset distance τ used to describe the degree of inter-particle interaction, the analytical expression of the mutual-coupling dipole moment under the two types of the electric field is obtained, respectively. An original model is established, and by comparison with the finite element method, it is found that even when D = 0.1R and ε_pp/ε_f = 25, the proposed model can describe the inter-particle interaction effectively, and its computational precision better than that of the classical model, which can realize the accurate computation of the electric field distribution around the particle-particle rotating system.

Measure for intensity of electrostatic interaction between two disjoint sets of charged conductors is introduced, and it is called relative intensity of interaction (RII). Firstly, we examine properties and we found various forms and upper bounds for RII between charged conductors and neutral conductors. The most important derived expression for RII is in terms of Schur complement of original capacitance matrix and capacitance matrix of system without neutral conductors. RII between two disjoint sets $S_1$ and $S_2$ of arbitrarily charged conductors is bounded above by sum of RII’s between charged set $S_1$ and neutral set $S_2$, and vice versa.

Electric charges in liquids are at the basis of numerous applications and may drive industrial hazards. The Thermal Step Method is applied to liquid/solid interfaces to validate the use of thermal stimuli techniques for space charge measurements in dielectric liquids. Experimental results obtained for different electrical double layers are presented and discussed. They show that thermal convection has no significant contribution to the signal compared to the response of the charges from the solid/liquid interface. The measured signals are in accordance with the classical theory of thermal methods in solids and are consistent with the behavior expected from numerical simulations.

An air-assisted electrostatic spraying unit along with a set-up to measure the spray current was developed. Response surface methodology was used to optimize the performance of the developed electrostatic spraying unit. The optimum parameters such as electrode diameter, electrode voltage, electrode position and target distance for maximizing charge-to-mass ratio (CMR) were determined to be 30 mm, 2000 V, 0 mm and 400 mm, respectively Predicted CMR under optimal conditions was experimentally validated. Furthermore, charged spray demonstrated 1.5 to 4.6 times higher droplet deposition with lower uniformity coefficient (2.13–2.14) and relative span factor (0.84–0.9) compared to uncharged spray.

This study presents a new electrostatic separation device for recovering high-purity metals and plastics from waste electrical and electronic equipment. The device is constituted by a rotating plate conveyor, an air suction system, and a vibrating hopper. It utilizes electro-adhesion force to selectively attract metal particles onto the conveyor surface, while precisely calibrated suction air effectively collects plastic particles into a dedicated box. A key feature is the employment of a low-level AC high voltage, significantly enhancing operational efficiency and safety compared to conventional electrostatic methods. Experimental results demonstrate high performance, achieving recovery and purity rates of up to 100 % depending on applied voltage and airflow settings.

An established formula for capacitance C of a thin metal disc printed on a dielectric substrate with height h and relative permittivity ${\epsilon }_r\ge 2.2$, backed by a conducting ground plane, is inverted into a closed formula. The latter yields disc's radius r for a given C and a given substrate, with an accuracy of 5 % of C or better if $r\ge h/2$. It will save the design engineer time, whose alternative is to resort to a numerical field solver and go by trial and error.

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Carbon dioxide captured from the atmosphere can be reduced to carbon monoxide, which can then be used as a fuel or material for conversion to organic compounds and for gas synthesis. However, currently, this energy source has low efficiency and its use is impractical because of the relatively low atmospheric CO₂ concentration, which disperses input energy. Therefore, it is important to concentrate atmospheric CO₂ during pretreatment. In this study, a plasma reactor is partially filled with an adsorbent and atmospheric air is allowed to flow into the reactor after the removal of water vapor using a condenser and silica gel to adsorb atmospheric CO₂ (i.e., the adsorption process). During desorption and reduction, nonthermal plasma flow is generated via dielectric barrier discharge, while nitrogen is flowed into the reactor to reduce atmospheric CO₂ (i.e., the desorption–reduction process). As a result, the CO₂ concentration reaches 545 ppm in 230 min during the adsorption process and 5519 ppm in 12 min during the desorption–reduction process. The CO concentration increases to 60 ppm in 12 min during the desorption–reduction process. The conversion and energy efficiencies are 1.1 % and 1.9 × 10⁻² %, respectively. The introduction of the adsorption process not only increases the concentrates CO₂ but also decreases the concentration of water vapor in the reactor and generates more CO, thereby increasing the energy efficiency. Therefore, the introduction of an adsorption process is extremely important for improving the concentration and reduction of CO₂.

This paper presents the design of a novel atomized corona discharge coupled screen electrode dust collector, which integrates electrostatic capture and wet electrostatic dust removal technologies. The upper part of the dust collector features an atomized corona discharge electrode utilizing a threaded-wire hole design with uniform water distribution. This design effectively addresses the issue of electrode fatness that may arise from uneven distribution of the discharge electrode. In contrast, the lower part of the collector is equipped with four side-by-side silk screen electrodes, which serve to expand the dust collection area, facilitate secondary particle capture, and consequently enhance dust removal efficiency. The study delves into a detailed analysis of the impact of various parameters on discharge characteristics and dust removal efficiency, culminating in the identification of optimal parameters.