High Voltage Electrical Discharges Research Articles

An innovative technique for the extraction and stability of polyphenols using high voltage electrical discharge

An innovative technique for the extraction and stability of polyphenols using high voltage electrical discharge

Research of heat conductivity of quartz material

In the article the results of a study of heat conductivity and thermal resistance of quartz-containing materials were presented. The object of the study was a quartz mineral from the Aktas deposit, located in the Ulytau district of the Karaganda region. The initial size was a piece of quartz mineral measuring 5–10 mm, which was disassembled mechanically. To prepare the samples under study, quartz powder 0.2 mm thick, crushed by the electric pulse method, was used. Electropulse technology is one of the methods based on the influence of Yutkin, accompanied by the formation of a specially formed high-voltage pulsed electrical discharge inside a volume of liquid. The pulse discharge frequency of the electrohydropulse installation for grinding the mineral to the required fraction was f = 3 Hz, the pulse capacitor capacitance C = 0.4 μF, the pulse discharge voltage U = 18–37 kV. The samples under study were made in the following dimensions: width 100 mm, length 100 mm, height 25 mm. To evaluate the thermophysical properties of manufactured samples in a stationary mode, the ITP-МG4 “100” installation was used, which determines the heat conductivity and thermal resistance of materials for thermal insulation of industrial equipment and pipelines in accordance with GOST 7076, based on the thermoelectric method, and GOST 30256, based on the thermal probe method. As a result of the study, a graph of the temperature dependence of heat conductivity and thermal resistance of quartz-containing materials was obtained. Based on the results obtained, it was established that the thermophysical parameters of the sample containing quartz are lower compared to the sample consisting of cement.

Ignition Features of a High-Voltage Electric Discharge in Water Under Conditions of Deep Oil Wells

Ignition Features of a High-Voltage Electric Discharge in Water Under Conditions of Deep Oil Wells

(Invited) Numerical Simulation of an Atmospheric Pressure Streamer Discharge and Induced Chemical Reactions

Streamer discharges are a type of non-thermal plasma produced by high-voltage electrical discharges, and have great potential as highly reactive chemical reaction fields. This is mainly due to the generation of high energy electrons that produce chemically active species. The applications of non-thermal plasma have attracted considerable interest in a wide range of industries. However, each radical has a different role in the plasma application and their reaction mechanism is also different. It's therefore important to understand exactly when, where and how much of these reactive species are produced in order to improve the treatment efficiency of atmospheric pressure plasma applications. Against this background, the aim of this study is to develop a simulation model capable of accurately predicting the chemical reactions of radicals. With a sufficiently validated simulation model, it would be possible to use such a model to design chemical reaction fields.The model consists of the first-order electrohydrodynamic model for electrons and positive and negative ions within the drift-diffusion approximation. Axis-symmetric coordinates were used to simulate the streamer discharge in air at atmospheric pressure. The electron transport and source parameters were calculated using two-term bltzmann equation and published electron impact cross-sections. The chemical reaction model used in this study includes electron impact collisions (excitation, ionisation, dissociation, recombination, attachment and detachment), ion recombination and the reactions of neutrals. In order to demonstrate the validity of the simulation, the light emission of the discharge is first compared between experiment and simulation. Then the spatial and temporal variations of each radical are simulated and compared with the simulation. In this talk, I will present the process of validation and verification (V&V) of the streamer discharge simulation and then the mechanism of radical production revealed by the simulation.

Enhancement Petrophysical Properties of Carbonate Reservoirs Using Plasma Channel Technology, Case Study: Yamama Formation, South of Iraq

Carbonate reservoirs are significant hydrocarbon productions, but their complex and heterogeneous nature often poses challenges in maximizing oil and gas recovery. Traditional methods for enhancing petrophysical properties have shown limited success in carbonate formations. However, new advancements in Plasma Channel Technology have shown promising results in improving the reservoir's petrophysical properties. The application of Plasma Channel Technology is considered as a novel approach to enhance the petrophysical properties of carbonate reservoirs. Plasma channel technology involves the controlled application of high-voltage electrical discharges to create conductive channels (new porosity) within the reservoir units. These channels serve as preferential pathways for fluid flow (permeability) and facilitate enhanced oil and gas recovery. The main objective of this study is to show the key aspects of the enhancement of the Yamama reservoir properties using Plasma Channel Technology minimizes the need for chemical additives to reduce operational costs and environmental impact. Therefore, Yamama Formation is studied in two oil wells Snd-1 and Snd-2, six core samples from reservoir units within the Yamama succession were studied to determine porosity using a Scanning Electron Microscope which provides valuable insights into their internal structure and porosity characteristics in these samples. A comparison had been done between porosities within rock samples before and after application of Plasma channel technology, where the porosity was ranging from micropores (10 nm) to mesopores (10-50 nm) in some samples before voltage electrical discharges, while it reached mesopores (20-50 nm) to macropores (more than 500 nm) after voltage electrical discharges.These pores have been increased in size if there was higher voltage which means enhancement in the petrophysical properties in the reservoir.

Advanced and Potential Methods for Extraction of Bioactive Compounds from Avocado Peel—A Review

Extraction techniques are continuously developed by the scientific community. Meanwhile, avocado peel is a by-product of avocado processing and a source of bioactive compounds. The purpose of this review was to summarize the use of advanced techniques for extracting bioactive compounds from avocado peel to help understand which techniques have and have not been applied to avocado peel. Three primary databases were used to collect the information, including Google Scholar, Scopus, and Web of Science, by using the keywords “avocado”, “peel”, and “extraction”. Additional keywords related to the extraction technique were also used, including “Microwave-Assisted Extraction”, “Ultrasound-Assisted Extraction”, “Enzyme-Assisted Extraction”, “Pressurized Liquid Extraction”, “Supercritical Fluid Extraction”, “Natural Deep Eutectic Solvents”, “Three-phase partitioning (TPP)”, “Pulsed-Electric Field”, “High Voltage Electric Discharge Plasma”, “Centrifugal Partition Extraction”, and “Surfactant-Mediated Extraction”. The results show that microwave-assisted extraction, ultrasound-assisted extraction, enzyme-assisted extraction, pressurized liquid extraction, supercritical fluid extraction, TPP, and natural deep eutectic solvent extraction have been used to retrieve bioactive compounds from avocado peel. Other techniques have not yet been applied for the extraction of bioactive compounds from avocado peel. This article is the first review discussing the advanced extraction technique for retrieving bioactive compounds from avocado peel. This article creates a paradigm for future studies.

The effect of high voltage electrical discharge (HVED) treatment on small seed plants

The effect of high voltage electrical discharge (HVED) treatment on small seed plants

Epilepsy secondary to brain injury by electrocution: A case report

Introduction: According to the Yearbook of Accidents of Electrical Origin for the year 2022, 853 accidents due to electric shock were reported in Brazil, of which 592 died, a reduction of 12.2% in mortality compared to the previous year. Three conditions elucidate trauma switches caused by the passage of electric current, the regulatory alterations by the passage of electric current, the conversion of electrical energy into thermal, known as the Joule effect, and muscle damage by the electrical stimulus of exacerbated contractions. Case Report: A 51-year-old male patient was followed up on an outpatient basis due to a nervous breakdown caused by accident with a high-voltage electrical discharge 15 years ago. After the event, he evolved with conduction aphasia, homonymous hemianopia on the right, hypoesthesia on the right side of the body, dysmetria on the right upper limb, and epileptic seizures of focal onset, evolving into tonic-clonic seizures. For seizure control, carbamazepine 200 mg 3 times a day was administered, with complete seizure control since then. Conclusion: Therefore, it is important to emphasize that the damage caused by electrocution to the central nervous system (CNS) is varied. Still, due to the patient’s clinical presentation, his neuroimaging findings, and his history, this is epilepsy secondary to electrocution. Encephalomalacia demonstrates a large scar in the brain tissue, and its control of seizure episodes with the adopted pharmacotherapy also corroborates.

A generalized physical principle of development of plasma channel of a high-voltage pulse spark discharge in a dielectric

Goal. Development of the generalized physical principle of development of plasma channel of a high-voltage electrical pulse spark discharge in the homogeneous dielectric of the different aggregate state. Methodology. Basis of physical optics, theoretical electrical engineering, electrophysics bases of technique of high-voltage and large pulse currents, bases of high-voltage pulse technique and measuring technique. Results. Development of physical principle of development of plasma channel of an electric pulse spark discharge is executed in a homogeneous gas dielectric on the applied example of the use in calculations and experiments of the double-electrode discharge system (DEDS) with a long air interval, testing action of standard interconnect аperiodic pulse of high-voltage of temporal shape of Tm/Тd≈200 μs/1990 μs of positive polarity. The generalized formula is got for the calculation of total length of lc of the real way of development of an pulse spark discharge in an air dielectric, which allowed to formulate the offered physical principle in the following kind: «The plasma channel of an pulse spark discharge in a gas dielectric spreads from one of its points to other after a way length of lc, providing the least falling on it of electric voltage of Uc». It is shown that this principle in the first approaching can be applied and to the homogeneous liquid and hard dielectrics. Comparison of the developed physical principle of distribution of plasma channel of an electrical spark discharge is executed in a dielectrical environment with fundamental Fermat physical principle (a law) for distribution of light in an optically transparent environment, which specifies on mathematical likeness and closeness on destiny of these physical principles. Calculation estimations of falling of electric voltage of Uc on total length of lc of the real zigzag way of development in the air dielectric of DEDS a «edge-plane» with the least length of its discharge interval of lmin=1,5 m is presented, that a value Uc does not exceed 9 % from the experimental level of aggressive voltage of Umd≈611,6 кV in this DEDS for the аperiodic pulse of voltage of Tm/Тd≈200 μs/1990 μs. It is set that the estimated time of td advancement of leader channel of electric pulse discharge in air DEDS (lmin=1,5 m) on its real way total length of lc≈1,53 m makes td≈15,3 μs, and experimental duration of cut of Tdc of the indicated аperiodic impulse of voltage utilized in experiments, characterizing time of short circuit by the plasma channel of discharge of air interval in DEDS, appears equal Тdc≈td≈17 μs. Originality. The generalized physical principle of development of plasma channel of a high-voltage electrical pulse spark discharge is first developed in the homogeneous dielectric of the different aggregate state. Practical value. Application in electrical engineering practice and high-voltage pulse technique of the offered principle of distribution in the dielectrics of plasma channel of an pulse spark discharge will allow to develop both new and to perfect the existent methods of computer design of electro-discharge processes in the gas, liquid and hard insulation of different high-voltage electrical power engineering and electrophysics devices, directed on the increase of reliability of their operation.

Microstructure and Phase Composition of Ti-Al-C Materials Obtained by High Voltage Electrical Discharge/Spark Plasma Sintering.

Titanium-based composite materials arouse interest in fields like aerospace, transportation, medicine, and other applications. This research project presents the analysis of phase composition of sintered Ti-Al-C composite materials under high voltage electrical discharge. The new technology, described in the previous work of the authors, allows to synthesise the composites containing various intermetallics, carbides, and nanostructures. The samples of Ti-Al-C powder composites were tested by SEM, Raman spectroscopy, and XRD. It was determined that the treatment of the powder by high voltage electrical discharge (HVED) and further sintering at high temperatures using the spark plasma sintering (SPS) method encouraged the formation of the intermetallic reinforcing phases, carbides, and different nanocarbon structures like graphene and fullerenes, as well as pure graphite. Intermetallic phases and nanocarbon structures improved the mechanical and physical properties of the composites. By using the experimental methods mentioned above, the phase composition of Ti-Al-C powder composites obtained at different sintering temperatures was determined. It was revealed that new composite materials produced by HVED and further SPS were rich with carbides, intermetallics, and MAX phases. Therefore, the carbon nanostructures (graphene and graphite) were detected existing in the structure of the produced new Ti-Al-C composite material. All these reinforcing particles improved the microstructure and the mechanical properties of the composites, as was proved in the previous research by the authors and by the different scientific resources. This project is a pilot experimental work, therefore not all peaks of Raman and XRD were detected; they will be analysed in future works.

Recent advances incombined Avant-garde technologies (thermal-thermal, non-thermal-non-thermal, and thermal-non-thermal matrix) to extract polyphenols from agro byproducts.

Because food byproducts (waste) are rich in phytoconstituents, valorizing them is crucial for global food security. However, conventional extraction (CE), including decoction, maceration, Soxhlet, etc., for agro byproducts' polyphenol extraction are time-consuming and rely significantly on vast volumes of potentially aggressive solvents. Hence, Avantgarde extraction technologies, including non-thermal (high hydrostatic pressure (HHPE), pulsed-electric field (PEF), high voltage electrical discharges (HVED), etc.) and thermal extraction (supercritical fluid (SCF), subcritical water extraction (SWE), microwave-assisted extraction (MAE), etc.), as well as their thermal combinations (SCF-PLE, SCCO2-SWE, SCCO2-MAE, etc.), non-thermal combinations (HHPE + UAE, PEF + UAE, HVED + UAE, etc.) and combined thermalnon-thermal (MAE-UAE, etc.) are increasingly replacing CE. However, a review of combined Avant-garde extraction escalation technologies (non-thermal/thermal extraction matrix) for extracting polyphenols from agro-byproducts is limited. Hence, this manuscript reviewed Avant-garde extraction technologies (non-thermal/thermal extraction matrix) for extracting phenolics from agro-byproducts in the last 5 years. The key factors affecting polyphenols' extraction from the byproduct, the recent applications of Avant-garde technologies, and their principle were reviewed using databases from Web of Science and Lens.org. The results demonstrated that combined Avant-garde extraction escalation technologies increase extractability, resulting in polyphenols with higher extraction rates, fewer contaminants, and preservation of thermosensitive components. Therefore, combined Avant-garde extraction technologies should be explored over the next five years. Implementing an integrated process and the strategic sequencing of diverse Avant-garde extraction technologies are important. Thus, further investigation is required to explore the sequencing process and its potential impact on the extraction of phenolics from agro-byproducts.

Experimental study on the dynamics of a spark bubble near the top of a cylinder and associated annular secondary cavitation bubbles

This paper presents an experimental study focused on the annular secondary cavitation caused by the interaction between a high-voltage spark bubble and a cylinder. A 2000 V high-voltage underwater electric discharge was used to create the bubble, which reached a maximum diameter of approximately 31 mm. High-speed photography was employed to capture the behavior of the spark bubble and the induced secondary cavitation bubbles. The formation and evolution of the annular secondary cavitation bubbles near the cylinder's edge were captured and analyzed. The study classified the morphology of the annular secondary cavitation bubbles into three different types based on various bubble distances and cylinder diameters. Notably, unique bubble morphologies, such as the terraced bubble shape, were identified, resulting from the coupling between the spark bubble, the annular secondary cavitation bubble, and the cylinder. The interaction between the annular secondary cavitation bubble and the spark bubble, including coalescence, and the resulting effects on bubble shape and period were investigated. The changes of secondary cavitation bubbles are compared when the cylinder has different chamfer angles. Moreover, the study examined the dynamic characteristics of the bubbles, including their shape evolution, jetting behavior, period length, and pressure pulses upon collapse, at various distances from the top-surface of cylinders with different diameters. The experiment also introduced flow visualization with dye into spark bubble experiments for the first time to trace the vortex around the annular secondary bubble. Additionally, the transparency of bubbles in the images was improved through multi-source lighting techniques.

Effect of high-voltage electrical discharge (HVED) at high frequency on vacuum freeze-drying time and physicochemical properties of blueberries

Vacuum freeze-drying provides high-quality food products. However, it requires long operating times and high energy consumption. High voltage electrical discharge (HVED) is an emerging technology that could enhance freeze-drying rates and final product quality. This study aimed to evaluate the effect of HVED at high frequency (200 kHz) on freeze-drying kinetics of blueberries (effective moisture diffusivity, drying times) and the physicochemical properties of the resulting freeze-dried fruits. Blueberries were pretreated at different electric field strengths (10, 20, and 30 kV/cm) and operational times (10, 20, and 30 s) and freeze-dried until constant weight. The HVED treatment at 30 kV/cm and 30 s exhibited the best moisture diffusivity values and reduced drying time by at least 30% compared with untreated samples. Samples treated with HVED and freeze-dried preserved their shape and prevented shrinkage. Applying HVED as a pretreatment electrotechnology can help improve the efficiency of freeze-drying and the quality of dried food products.

Experimental Studies of Hydrodynamic and Energy Characteristics of a High-Voltage Electrochemical Explosion in Limited Liquid Volumes

In this paper, the dependence of the charging voltage, stored electrical energy, and the mass of the combusted exothermic mixture on electrical, energy and hydrodynamic characteristics of a high-voltage electrochemical explosion (HVEE) in limited volumes of liquid on is experimentally studied. A comparison with other methods of initiating an electric discharge under similar conditions was made. The results established that the HVEE makes it possible to carry out a high-voltage electric discharge with low energy losses (less than 9%) and to realize an electrical breakdown mode close to aperiodic. It has been found that HVEE can generate pressure waves with an amplitude up to 37% and a pulse up to 45% larger (at a charging voltage of 25 kV or higher) than that of an electric explosion of an initiating metallic conductor of optimum length under the same initial conditions. It was found that an increase in the charging voltage leads to an increase in the amplitude and pulse of the generated pressure wave along a linear dependence. A compre-hensive analysis of the dependences of the energy and hydrodynamic characteristics showed that the main influence on the formation of the pressure wave pulse during the HVEE is provided by both the stored electrical energy and the interconnection between the electrical parameters of the discharge circuit and the mass of the burning exothermic mixture, which determines the shape of the discharge characteristics.

Electric performance of hybrid busbar joints under service and high voltage conditions

This paper is focused on hybrid busbar joints with a twofold objective of understanding the differences in electrical resistance under service conditions and evaluating their performance when subjected to hazardous high voltages. Three different types of joints fabricated by conventional bolting, friction stir spot welding and injection lap riveting are selected and two different experimental setups are used to allow the hybrid busbars to be tested up to high voltage electrical discharges of 30 kV. The work is an enhancement of previous experimental and numerical investigations of the authors in the field with results showing no signs of damage or catastrophic failure when the different types of busbars are subjected to high voltage electrical discharges. Results also confirm the good overall performance and advantages of injection lap riveted hybrid busbar joints against bolted and friction stir spot welded.

Investigation of the Microstructure of Sintered Ti-Al-C Composite Powder Materials under High-Voltage Electrical Discharge.

Dispersion-hardened materials based on TiC-AlnCn are alloys with high heat resistance, strength, and durability that can be used in aircraft and rocket technology as a hard lubricant. The titanium-rich composites of the Ti-Al-C system were synthesized via the spark plasma sintering process. Composite powder with 85% of Ti, 15% of Al, and MAX-phases was processed using high-voltage electrical discharge in kerosene at a specific energy of 25 MJ kg-1 to obtain nanosized particles. This method allows us to analyze the most efficient, energy saving, and less waste-generating technological processes producing materials with improved mechanical and physical properties. An Innova test indentation machine was used to determine the hardness of the synthesized composites. The microhardness of Ti-Al-C system samples was determined as approximately 500-600 HV. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were performed to identify the hard titanium matrix reinforced by intermetallic phases and the clusters of carbides. Three types of reinforcing phases were detected existing in the composites-TiC, Al4C3, and Al3Ti, as well as a matrix consisting of α- and β-titanium. The lattice parameters of all phases detected in the composites were calculated using Rietveld analysis. It was determined that by increasing the temperature of sintering, the amount of aluminum and carbon increases in the carbides and intermetallic phases, while the amount of titanium decreases.

Application of radiation technologies, increase of catalysts surface activity

The catalyst surface was processed in the high-voltage electrical discharge device in oxygen environment. Continuous active oxide centers formed on the surface and complete filling of the surface with oxygen occur, and its thermo-physical properties, thermo-luminescence curves, scanning electron microscope and ESR spectrometers were studied. It was determined that the activity of the catalyst at values of the absorbed dose [Formula: see text][Formula: see text]kGy is many times higher than that of conventional catalysts. Thus, due to the sorption volume of the surface, the volume of the product formed in the liquid phase increases by 1.6 times.

Alternative methods for RuBisCO extraction from sugar beet waste: A comparative approach of ultrasound and high voltage electrical discharge

Ultrasound (US) and high voltage electric discharge (HVED) with water as a green solvent represent promising novel non-thermal techniques for protein extraction from sugar beet (Beta vulgaris subsp. vulgaris var. altissima) leaves. Compared to HVED, US proved to be a better alternative method for total soluble protein extraction with the aim of obtaining high yield of ribulose-1,5-bisphosphate carboxylase-oxygenase enzyme (RuBisCO). Regardless of the solvent temperature, the highest protein yields were observed at 100% amplitude and 9 min treatment time (84.60 ± 3.98 mg/gd.m. with cold and 96.75 ± 4.30 mg/gd.m. with room temperature deionized water). US treatments at 75% amplitude and 9 min treatment time showed the highest abundance of RuBisCO obtained by immunoblotting assay. The highest protein yields recorded among HVED-treated samples were observed at a voltage of 20 kV and a treatment time of 3 min, disregarding the used gas (33.33 ± 1.06 mg/gd.m. with argon and 34.89 ± 1.59 mg/gd.m. with nitrogen as injected gas), while the highest abundance of the RuBisCO among HVED-treated samples was noticed at 25 kV voltage and 3 min treatment time. By optimizing the US and HVED parameters, it is possible to affect the solubility and improve the isolation of RuBisCO, which could then be purified and implemented into new or already existing functional products.

Synergy Effect during Water Treatment by Electric Discharge and Chlorination

Water treatment, such as disinfection, is an integral stage of its use for human life. The use of plasma technology with high-voltage electric discharge in a liquid for obtaining a bactericidal effect is discussed. It has been experimentally shown that among the factors accompanying a high-voltage electric discharge in a liquid and affecting the viability of bacteria, cavitation is the main one. Simultaneous use of electric discharge in the special cavitation mode and oxidizing agents makes it possible to achieve stable disinfection of water. At the same time, bactericidal doses of the oxidizing agent are reduced by a factor of 10 relative to existing standards, and the energy costs for electric discharge exposure, enhanced by small doses of an oxidizing agent, are reduced by 6 times compared to the costs of disinfection by only an electric discharge.

Development of Determination Methodology of Electrical Conductivity of Titanium-based Composites

The Ti-based metal matrix composite samples are novel, fabricated by using high voltage electric discharge and spark plasma sintering processes. They have potential usage in the aviation industry. A research that allowed measuring an electrical conductivity of Ti-based composites was performed. A collinear four-point probe method was chosen for measurement of electrical conductivity. Needle-like probes were used to contact the tested sample. Other aspects of the measurement setup are discussed and selected according to relevant literature. A simulation was performed using COMSOL software to validate the measurement method. Furthermore, a simulation performed for contact force of the probes was performed. A 3D model of the measurement tool was created and designed. The measurement setup was tested and validated by using a copper sample. electrical resistance of Ti-based composite samples was measured, and electrical conductivity was calculated. Furthermore, samples were measured at different temperatures and resistivity dependence to temperature was presented. Experimental results are compared to similar research results.