High-voltage Discharge Research Articles

Confined sulfur electrode to achieve quasi-solid state sulfur conversion reaction in Li[sbnd]S battery

An ordered mesoporous carbon (OMC) inlaid with micropores was derived via a hard template method. OMC micropores loaded with sulfur (S-OMC) were used as a cathode for the LiS battery. A comparison of UV–Visible analysis of S, S-OMC and S-loaded carbon nanotube (S-CNT) indicated lower solubility of S into the electrolyte from S-OMC. Controlling the solubility of S into the electrolyte is important to reduce the polysulfide concentration in the electrolyte. Cyclic voltammetry and galvanostatic charge-discharge measurements of S-OMC indicated the merging of solid-S → polysulfide and liquid-polysulfide → lower-order lithium sulfide transitions. Instead of the two-plateau discharge curve normally observed in S‑carbon composite electrodes, a single sloppy discharge curve was observed with S-OMC. Which possibly due to lower S concentration in the electrolyte, which results in reduced polysulfide concentration and lowers dynamic viscosity of the electrolyte. At 0.2C, nearly 1254 mAh g−1 of capacity was realized with capacity loss <5 mAh g−1 even after 50 cycles in lean electrolyte condition (3 μL/mgS). Distributed relaxation time analysis performed using a series of Nyquist plots recorded at various stages of charging and discharging indicate sudden decrease in the solution+contact resistance as a result of improved electrolyte access into the pores due to sudden volume contraction associated with Li2S → S at potentials >2.2 V in the confined zone. Due to the confinement effect, the growth of Li2S occurs slowly both at the anode and cathode, thereby enabling high voltage and capacity discharge with S-OMC compared to the S-CNT.

Evaluation of spatial distribution of the oxidation of glass beads simulating soil using high-voltage pulsed discharge

The spatial distribution of soil oxidation using a high-voltage pulse generator was evaluated using indigo carmine. The results showed that the amount of indigo carmine decolorization increased with increasing charging voltage and energy input. It was also found that the decolorization of indigo carmine occurred on the surface of the needle electrode, in the discharge path, and near the ground electrode. The probability of discharge penetrating soil increased with decreasing the gap length between the electrode tip and soil surface, which promoted the decolorization reactions. The amount of indigo carmine decolorization per volume decreased with increasing soil depth. When the soil depth was large, discharges reaching the ground electrode could not be confirmed. This suggests that the oxidation reaction of indigo carmine depends on a discharge that penetrates the soil.

Encapsulation of Rosemary Extracts using High Voltage Electrical Discharge in Calcium Alginate/Zein/Hydroxypropyl Methylcellulose Microparticles.

The increased demand for functional food with added health benefits is directing industrial procedures toward more sustainable production of naturally added bioactive compounds. The objective of this research was to investigate the potential of bioactive compounds from rosemary extract obtained using high-voltage electrical discharge as a green extraction method, for microencapsulation as a protective method for future application in functional food. Four types of microparticles were made via the ionic gelation method using alginate (Alg), zein (Z), and hydroxypropyl methylcellulose (HPMC) biopolymers and were analyzed considering the physicochemical properties. The diameter of dry microparticles ranged from 651.29 to 1087.37 μm. The shape and morphology analysis of microparticles showed that the obtained microparticles were quite spherical with a granular surface. The high encapsulation efficiency was obtained with a loading capacity of polyphenols up to 11.31 ± 1.47 mg GAE/g (Alg/Z microparticles). The microencapsulation method showed protective effects for rosemary polyphenols against pH changes during digestion. Specifically, the addition of both zein and HPMC to calcium-alginate resulted in microparticles with a prolonged release for better availability of polyphenols in the intestine. This research background indicates that the release of rosemary extract is highly dependent on the initial biopolymer composition with high potential for further functional food applications.

Numerical simulation of the breakdown process of dielectric in high voltage pulse discharge

In order to study the breakdown process of the insulating medium of the needle-needle electrode under the action of high-voltage pulse discharge, the HV-LAB simulation software was used to study the discharge channel formed in the three kinds of insulating media, namely water, transformer oil, and air, and the three-dimensional model of the discharge breakdown insulating medium was designed. The process of discharge channel expansion, voltage, current, power, and energy loss in the discharge channel is analyzed. The results show that in the process of high-voltage pulse discharge breakdown of the insulating medium, the formation time of the discharge channel of transformer oil is long, the energy is accumulated, the number of discharge channels is less, the horizontal isopotential lines are dense, and the energy is concentrated. Under the same discharge conditions, the energy consumption of transformer oil in the process of high-voltage pulse discharge is the least. The results of this study can provide a reference for the selection of high-voltage crushing insulation medium.

Synthesis of Combined Energy Sources Based on High-Voltage Electrochemical Explosion

An algorithm of the stage-by-stage synthesis of combined energy sources based on a high-voltage electrochemical explosion (HVECHE) was developed. The algorithm provides the necessary space-time force and energy impact on processing objects to perform specified technological operations. At the first stage, the synthesis of an energy source based on a high-voltage electric discharge in condensed media was done by means of solving inverse synthesis problems and, as a result, determining the required total energy with its subsequent optimal separation into electrical and chemical components. Experimental studies of the dependence functions of the force impact on the processing object on the energy characteristics of the HVECHE were carried out. Based on those studies, the criteria for the optimal proportion between the electrical and chemical components of the required total energy were determined. An example of a specific use of the developed algorithm for the synthesis of a combined energy source based on the HVECHE was given, which confirms the possibility to use this algorithm for engineering calculations.

Erosion of an Electrode during a High-Voltage Electric Discharge in a Liquid

Erosion of an Electrode during a High-Voltage Electric Discharge in a Liquid

Uniform Action of Plasma of a Nanosecond Pulsed High-Voltage Discharge on the Surface of a Flat Anode

The results of an experimental study of the effect of a plasma of a nanosecond pulsed high-voltage discharge in air at atmospheric pressure, excited in a sharply nonuniform electric field, on the surface of a flat-grounded electrode are presented. It is shown that at relatively large interelectrode distances between the pointed cathode and the flat anode, a diffuse discharge is implemented, which ensures a uniform action of the discharge plasma on the anode surface.

Extraction of Mycosporine-like Amino Acids and Proteins from the Agarophyte Gelidium corneum Using Pulsed Power Techniques

Gelidium corneum (syn. sesquipedale) is an industrially and ecologically important species of red alga used for the production of high-quality agar. However, the species is also of growing interest for the production of other valuable compounds, such as mycosporine-like amino acids (MAAs), with potential cosmeceutical and biomedical applications. Novel methods using two pulsed power techniques, high-voltage electrical discharges (HVED) and pulsed electrical fields (PEF), were evaluated for efficacy of MAA extraction. Algal suspensions were prepared at two ratios (1:20 and 1:40 w:v). Four different extraction protocols were compared: (i) high-voltage electrical discharges, (ii) pulsed electric fields, (iii) maceration at room temperature, and (iv) maceration at 50 °C. The algae were treated in three states: freshly harvested, dried, and powdered. HVED and PEF treatments were effective when performed on fresh algae, and in particular the HVED treatment resulted in yields of MAAs twenty times higher than the control: 0.81 ± 0.05 mg/gDry Weight (DW) vs. 0.037 ± 0.002 mg/gDW. This effect was not observed to the same extent when the algae were dried or powdered, although HVED remained the most selective method overall.

Investigation of high-voltage discharge in oil on a simulator with a different set of defects

Background: The article describes a device for simulating various insulation defects for use with acoustic control devices for power transformers included in the power supply system of railway transport. The parameters of the recorded signals of the simulator are given, which will make it possible to recognize various insulation defects when diagnosing power transformers under operating conditions which will help to avoid emergency modes and interruptions in the operation of the electric rolling stock of railways.&#x0D; Aim: experimental studies of a simulator with a different set of defects, obtaining the values of the parameters of acoustic control signals for various defects in the insulation of power transformers.&#x0D; Methods: experimental studies of automated means of acoustic control, development of technical means for simulating various defects in the insulation of power transformers, processing of acoustic control signals.&#x0D; Results: the block diagram of the simulator with a different set of defects is given, the values of the parameters of acoustic monitoring signals for various defects in the insulation of power transformers are given.&#x0D; Conclusion: the above device allows you to reproduce various defects in the insulation of power transformers, to recognize such defects according to the proposed parameters of acoustic control signals.

MODELING THE DYNAMICS OF HEAT AND MASS TRANSFER PROCESSES IN A TUBULAR HEAT EXCHANGER UNDER PULSED INFLUENCES

The paper discusses the results of experimental studies of the influence of the degree of inhomogeneity of a liquid flow on the dynamics of heat and mass transfer processes under pulsed impacts. High-voltage electric discharges in a liquid medium were used as impulse actions, through which an electro-hydraulic effect is realized, accompanied by the appearance of shock waves. The dynamics ofthe occurring nonlinear, rapidly changing heat and mass transfer processes at high hydraulic pressures cannot be described using differential equations. The simulation was carried out on the basis of the method of group consideration of arguments, the advantage of which is the construction of polynomial dependencies using a small amount of experimental data. The results of constructing polynomial dependences made it possible to reveal the synergistic effect of the influence of flow parameters on the dynamics of the impulse pressure amplitude and the intensity of heat transfer.

Elemental Analysis of Heated Soil Samples Using Laser-Induced Breakdown Spectroscopy Assisted with High-Voltage Discharges

In this study, a high-voltage (HV) oscillatory square pulse was used to re-excite the laser-induced breakdown spectroscopy (LIBS) signal produced by a nanosecond laser on different loamy soil samples at two different temperatures: ambient and 400 °C. The optimal delay was found for each experimental scheme to maximize the emission signal-to-noise ratio. The detection limits of various contaminants in the soil were studied for different experimental configurations. It was found that the lowest detection limits were achieved by combining HV discharges with LIBS on heated samples, resulting in improvements of up to a factor of 7 compared to LIBS on room temperature samples. Plasma characterization shows that the increased detection sensitivity is due to the rise in plasma temperature and electron density with HV re-excitation, while an increase in removed matter contributes to the emission intensification observed when samples are heated.

Stress wave analysis of high-voltage pulse discharge rock fragmentation based on plasma channel impedance model

High-voltage pulse discharge (HVPD) rock fragmentation controls a plasma channel forming inside the rock by adjusting the electrical parameters, electrode type, etc. In this work, an HVPD rock fragmentation test platform was built and the test waveforms were measured. Considering the effects of temperature, channel expansion and electromagnetic radiation, the impedance model of the plasma channel in the rock was established. The parameters and initial values of the model were determined by an iterative computational process. The model calculation results can reasonably characterize the development of the plasma channel in the rock and estimate the shock wave characteristics. Based on the plasma channel impedance model, the temporal and spatial distribution characteristics of the radial stress and tangential stress in the rock were calculated, and the rock fragmentation effect of the HVPD was analyzed.

The use of machine learning methods to predict the processes and results of high-voltage electric discharge processing of titanium powder in kerosene with the implementation of volume-distributed multi-spark discharge

The possibility of using machine learning methods to predict the results of high-voltage electric discharge treatment of titanium powder in a hydrocarbon liquid is studied. Distribution surfaces for the average particle diameter of Titanium powder. The amount of Titanium carbide formed during processing, and the number of spherical particles of titanium powder depending on the interelectrode gap and the number of pulses, when using volume-distributed multi-spark discharge and with Titanium powder concentration in kerosene of 0.07 kg / dm3, pulse repetition frequency 0.3 Hz and the energy of single discharge of 1 kJ, were obtained.

Effects of Static Pressure on Failure Modes and Degree of Fracturing of Sandstone Subjected to Inter-Hole Pulsed High-Voltage Discharge

This research aims to explore the fracturing behaviors of sandstone subjected to pulsed high-voltage discharge (PHVD) under different static pressures. An experimental method of rock fracturing induced by inter-hole PHVD was proposed. The static pressure was applied to the specimens, then the proposed method was applied to induce electrical breakdown testing under static loading. The microscopic fracture morphology of the sandstone was observed. The influences of the direction and level of static pressure on the crack length and fractal dimension of sandstone under the effect of PHVD were discussed. The results indicated that in the absence of static pressure, there are a discharge channel and multiple radial cracks in the sandstone after electric breakdown. The microscopic analysis implies that rock failure in the zone around the discharge channel is mainly influenced by the high temperature; while radial cracks are induced by shock waves. When static pressure is vertical to the discharge channel, tensile and compressive stresses concentrate in different parts around the discharge channel, which can remarkably alter the distribution zone and propagation path of cracks. In addition, the fractal dimension and total length of cracks first decrease, then increase with increasing static pressure. When static pressure is parallel to the discharge channel, the distribution characteristics and propagation direction of cracks are unchanged; however, under this loading mode, circularly distributed hoop tensile strains are generated at the zone around the discharge channel, which enables the fractal dimension and crack length increase with increasing static pressure.

Studies on the Control of Dermanyssus gallinae via High-Voltage Impulse

Dermanyssus gallinae, a parasitic mite that subsists on the avian blood of chickens, poses a considerable threat to the poultry industry. D. gallinae infestation can result in a plethora of detrimental effects for the host birds, including decreased egg production and anemia. Pyrethroid pesticides have been the primary means of combating this issue and have demonstrated high levels of efficacy. However, in recent years, D. gallinae has exhibited resistance to these chemicals, resulting in a marked decrease in their mortality; thus, an integrated control strategy in addition to the chemical use should be required for the sustainable control of this mite. This study confirms that D. gallinae can be effectively controlled through the utilization of high-voltage impulse discharges and that various electrical parameters possess optimal values that are required for mite control. The alterations in the body surface of the mite caused by high-voltage impulses were akin to those caused by heat, but no alteration in the elemental composition of the body surface was observed, suggesting a change in organization caused by currents flowing inside the exoskeleton. Comparatively, the mite control efficacy of high-voltage impulse was found to be substantially superior to that of ultraviolet light or ozone, with up to 95% more mites being killed in as little as 30 seconds.

Prospective life cycle assessment of recycling systems for spent photovoltaic panels by combined application of physical separation technologies

The design of an optimal system for recycling photovoltaic panels is a pressing issue. This study performed a prospective life cycle assessment using experimental and pilot data to reveal the effectiveness of the proposed technologies. The proposed technologies include aluminum frame separation; precise mechanical separation consisting of primary and secondary grinding; the hot-knife method for glass/ethylene-vinyl acetate separation; and high-voltage pulsed discharge that targets copper and silver in cell sheets. Implementing resource recovery technology decreases landfill waste because the hot-knife procedure facilitates the reuse or recycle of glass. The largest concentration of copper busbar is produced by high-voltage pulsed discharge, which can be easily incorporated into smelting processes. The blending of low-concentration metal waste with other trash and ore changes the concentration criteria accepted in the smelting operations. Applying the detailed inventory data for the metal concentrations in this investigation could enhance the outcomes.

Evaluation of Conducted Electromagnetic Interference Behavior of Copper Vapor Laser

High power and high repetition rate electrically excited copper vapor laser (CVL) is a strong source of radiated and conducted electromagnetic interference (EMI). The thermal energy required to raise the temperature (∼1600°C) to generate copper vapor and the required voltage pulse for population inversion is provided by the pulse generating unit (PGU). The PGU generates a voltage pulse of the order of ∼13 kV with a rise time of less than 100 ns and a current pulse in the range of ∼500 A with a similar rise time. The high voltage and current generated by PGU along with the high voltage pulse discharge in the laser tube serves as a prominent source of EMI and affects the performance of nearby electronic devices. This article presents a comprehensive study of conducted EMI from a high-power and high voltage discharge inside the CVL system and its impact on laser performance. The conducted noise from the laser is a function of laser impedance and is proportional to the magnitude of load mismatch. A simple and robust technique is presented to reduce the conducted noise from CVL. The correlation between the laser electrode pin configurations and the conducted noise is also presented.

High-voltage discharge characteristics of a hybrid-wall Hall thruster with an aft-loaded magnetic field

High-voltage discharge characteristics of a hybrid-wall Hall thruster with an aft-loaded magnetic field

Improvement of Sinapine Extraction from Mustard Seed Meal by Application of Emerging Technologies.

Sinapine is a phenolic compound found in mustard (Brassica juncea) seed meal. It has numerous beneficial properties such as antitumor, neuroprotective, antioxidant, and hepatoprotective effects, making its extraction relevant. In this study, the extraction of sinapine was investigated using three methods: (i) from a mustard seed meal defatted by a supercritical CO2 (SC-CO2) pretreatment, (ii) by the implementation of high-voltage electrical discharges (HVEDs), (iii) and by the use of ultrasound. The use of SC-CO2 pretreatment resulted in a dual effect on the valorization of mustard seed meal, acting as a green solvent for oil recovery and increasing the yield of extracted sinapine by 24.4% compared to the control. The combination of ultrasound and SC-CO2 pretreatment further increased the yield of sinapine by 32%. The optimal conditions for ultrasound-assisted extraction, determined through a response surface methodology, are a temperature of 75 °C, 70% ethanol, and 100% ultrasound amplitude, resulting in a sinapine yield of 6.90 ± 0.03 mg/g dry matter. In contrast, the application of HVEDs in the extraction process was not optimized, as it led to the degradation of sinapine even at low-energy inputs.

Effects of scandium doping on the electrochemical performance of cathode materials Na3MnTi(PO4)3 for sodium-ion batteries

A lately proposed NASICON-structured Na3MnTi(PO4)3 (NMTP) provides a promising solution that enables a large theoretical specific capacity and a high voltage discharge platform. However, it encounters a difficulty in electronic conductivity which obstructs its further implements. Herein, in this work we propose the Sodium-ion battery cathode materials Na3Mn1−xScxTi(PO4)3/C with different Sc contents (x = 0, 0.01, 0.03, 0.05, 0.07, 0.1), a potential cathode material for sodium-ion batteries with typical three-dimensional NASICON structure were synthesized by sol-gel method aiming to address the problem. Doping of Sc3+ in the NMTP structure was proved by powder X-ray diffraction and energy dispersive X-ray spectroscopy techniques. Impedance spectroscopy and galvanostatic intermittent titration technique results suggest that appropriate-proportion doping has dramatically enhanced the electrical conductivity and Na ion migration of the NMTP matrix. Na3Mn0.95Sc0.05Ti(PO4)3 exhibited a higher initial discharge specific capacity (123 mA h /g at 0.2 C, 111 mA h /g at 1 C) and the highest cycling stability (capacity retention of 93% after 250cycles at 0.2 C, capacity retention of 88% after 500 cycles at 1 C). In addition, Electrochemical Impedance Spectroscopy and X-ray diffraction tests revealed the reasons for the improved cycling stability of the materials due to doping. Furthermore, Na3Mn0.95Sc0.05Ti(PO4)3//hard carbon full cells also demonstrates ideal electrochemical properties.