High Voltage Electrical Discharges Research Articles

Electro Discharge Compaction of WC-Co Composite Material Containing Particles of Diamond

In the present paper, the formation of high hardness and large strength structure of WCCo composite material containing particles of diamond were investigated and optimal operating parameters were defined. Tungsten carbide - cobalt - diamond composite was produced by the method of high voltage electrical discharge together with applying mechanical pressure to powder compact. It was found that the density and hardness of composite material reach its maximum values at certain magnitudes of applied pressure and high voltage electrical discharge parameters. We found that there is [a maximum level -Comment: Don’t you mean a maximum level?] for the discharge voltage and applied pressure beyond which the powder WC-Co-diamond composite material disintegrates like an exploding wire. Near this level, the cobalt particles are in a fused condition and are redistributed in the compact volume due to magnetic pressure of discharge current pulse. [The distribution of magnetic pressure is defined by the distribution of a current density in the powder compact. The magnetic pressure is more homogeneous in powder compact volume when the skin effect is strong.-Comment: Are these two statements of fact or conclusions made based on experimental observations? - Answer: The first statement is fact and the second statement is conclusion made based on experimental observations.]

Visible and ultra-violet absorption spectra of aqueous solutions of transition metal salts affected by a high-voltage pulse electric discharge

The effect of a high-voltage pulse electric discharge (HVPED) on the electron spectra of CuSO4, Ni(NO3)2, NiCl2, CoSO4, and Co(NO3)2 aqueous solutions is investigated. It is found that the salt system activation by HVPED can change the configurations of electron shells of molecular ions. It is stated that the processes of post-activation structural relaxation of CuSO4/H2O solution are rather long-term. It is shown that the character of the HVPED effect on the electron spectra of solutions significantly depends on the solution composition and the intensity of interparticle interactions therein.

Transformations in Hydrocarbon-Mineral Mixture Contacting with Tamol Solution at High-Voltage Electric Discharge

Transformations in Hydrocarbon-Mineral Mixture Contacting with Tamol Solution at High-Voltage Electric Discharge

Electrical Solution to Fight Harmful Insects Influence of lamp-light color

A device for catching insects, using a high voltageelectrical discharge, called KAHRATRAP, is designed andbuild up by the first author of this paper. The aim of this paperis to des ...

Maladie de Bowen palmaire et arsenic

A large amount of wastes and by-products are generated during olive oil production process. Traditionally, these products have been considered as a problem. However, they constitute a great source of high-added value compounds, which have the potential to be used as food additives and/or nutraceuticals. Therefore, valorization of wastes and by-products from food industry kills two birds with one stone and addresses both the use of waste and by-products and societal health, thus greatly contributing for a sustainable food chain from an environmental and economical point of view.In the present review, current and new insights in the recovery of high-added value compounds from wastes and by-products generated during olive oil production process will be discussed. Several conventional (solvent, heat, grinding) and non-conventional methodologies (ultrasounds, microwaves, sub- and supercritical fluid extractions, pressurized liquid extraction, pulsed electric fields and high voltage electrical discharges) have been investigated for the recovery of high-added value compounds (polyphenols, fatty acids, coloring pigments (chlorophylls and carotenoids), tocopherols, phytosterols, squalene, volatile and aromatic compounds) from wastes and by-products generated during olive oil production process.Non-conventional technologies can constitute a promising tool to recover high-added value compounds from olive oil wastes and by-products. However, the content of these valuable compounds can vary greatly depending on the matrix and the efficiency in the recovery of these compounds is highly dependent of the technology used for extraction.

Quantification of Reductive Species Produced by High Voltage Electrical Discharges in Water

AbstractSummary: The formation of reductive species has already been documented in various advanced oxidation–reduction processes (AORP) such as ultrasound and radiation processes. Reductive species are important in degrading mixed aqueous wastes and nitro‐ and chloro‐contaminants to achieve higher degradation efficiencies than can be attained by the reaction of contaminants with hydroxyl radicals (the primary reactive species produced by all AORP). The present study quantifies the total amount of reductive species produced by aqueous phase high voltage pulsed electrical discharge, using chemical probes tetranitromethane and nitroblue tetrazolium chloride. The effects of various electrical, physical, and chemical parameters on the generation of reductive species are investigated. magnified image

Enhanced degradation of organic pollutant 4-chlorophenol in water by non-thermal plasma process with TiO2

The combined application of TiO2 photocatalyst and pulsed high-voltage electrical discharge process for the degradation of organic pollutant parachlorophenol (4-CP) in aqueous solution was tentatively investigated. The optimum conditions for 4-CP removal were applied voltage at 14 kV, electrode distance at 2 cm, pH at 6.5 (close to neutral solution), TiO2 concentration at 50 mg/L, gas source O2 at 100 L/h, and hybrid corona-streamer discharge mode. Introduced TiO2 into pulsed discharge plasma process under such optimum condition, the rate constant of 4-CP degradation (k cp) was greatly promoted, from 1.56×10−3 to 2.81×10−3 s−1, and energy efficiency for 4-CP removal was greatly enhanced by approximately one time, and it was attributed to more amounts of chemically active species (e.g., ozone and hydrogen peroxide, especially hydroxyl radicals) produced in pulsed discharge plasma process in combination with TiO2 photocatalyst.

The Roles of Ozone and Zeolite on Reactive Dye Degradation in Electrical Discharge Reactors

In this study high voltage pulsed corona electrical discharge advanced oxidation processes (AOPs) were applied to bleach and degrade C.I. Reactive Green 8 and C.I. Reactive Red 45 organic dyes in water solutions. Two types of hybrid gas/liquid high voltage electrical discharge (corona) reactors, known as hybrid series and hybrid parallel were studied. The difference between these reactors relates to electrode configuration, which affects the amounts of ozone, hydrogen peroxide and hydroxyl radicals produced. Experiments were conducted using dye concentrations of 20 mgl−1 and 75 mgl−1, with and without NH4ZSM5 zeolite addition in order to determine possible effects of added solid particles to total process efficiency. The role of ozone in combination with zeolites was assessed through comparative direct ozonation experiments with ozone supplied by an ozone generator. UV/VIS spectrophotometric measurements and measurements of total organic carbon (TOC) were used for the determination of decolorization and mineralization rates.

Features of a Wavetrain Emitted at High-Voltage Electric Discharge in Water

Features of a Wavetrain Emitted at High-Voltage Electric Discharge in Water

Electrohydraulic Discharge and Nonthermal Plasma for Water Treatment

The application of strong electric fields in water and organic liquids has been studied for several years, because of its importance in electrical transmission processes and its practical applications in biology, chemistry, and electrochemistry. More recently, liquid-phase electrical discharge reactors have been investigated, and are being developed, for many environmental applications, including drinking water and wastewater treatment, as well as, potentially, for environmentally benign chemical processes. This paper reviews the current status of research on the application of high-voltage electrical discharges for promoting chemical reactions in the aqueous phase, with particular emphasis on applications to water cleaning.

Decomposition of phenol by hybrid gas/liquid electrical discharge reactors with zeolite catalysts

Application of hybrid gas/liquid electrical discharge reactors and a liquid phase direct electrical discharge reactor for degradation of phenol in the presence and absence of zeolites have been investigated. Hybrid gas/liquid electrical discharges involve simultaneous high voltage electrical discharges in water and in the gas phase above the water surface leading to the additional OH radicals in the liquid phase and ozone formation in the gas phase with subsequent dissolution into the liquid. The role of applied zeolites, namely NH 4ZSM5, FeZSM5 and HY, were also studied. Phenol degradation and production of primary phenol by-products, catechol and hydroquinone, during the treatment were monitored by HPLC measurements. The highest phenol removal results, 89.4–93.6%, were achieved by electrical discharge in combination with FeZSM5 in all three configurations of corona reactors. These results indicate that the Fenton reaction has significant influence on overall phenol removal efficiency in the electrical discharge/FeZSM5 system due to the additional OH radical formation from hydrogen peroxide generated by the water phase discharge.

Hydrogen, Oxygen, and Hydrogen Peroxide Formation in Aqueous Phase Pulsed Corona Electrical Discharge

High voltage electrical discharges in water are of increasing interest for the degradation of organic compounds and destruction of biological species. The present study reports measurements of the rates of molecular hydrogen, molecular oxygen, and hydrogen peroxide formation in a pulsed positive needle-plane corona-like electrical discharge in water. In experiments for various solution conductivities, applied voltages, and discharge powers, the ratio of the molar rate of production of hydrogen:hydrogen peroxide:oxygen was approximately 4:2:1. The highest observed rate of hydrogen production was 1.3 μmol/s at discharge power of 37 W (or 0.25 g of H2/kW·h) at solution conductivity 50 μS/cm. The G-value for hydrogen production was 0.17 molecule of H2/100 eV, falling in the range of that found in the radiation chemistry literature (∼0−0.5 molecule of H2/100 eV, depending on scavenger concentration). A global reaction is proposed to add to existing kinetic models for the simulation of reactive species producti...

Influence of iron on degradation of organic dyes in corona

In this work application of AOPs such as Fenton process, aqueous phase high voltage electrical discharge (corona) and their combination have been studied for colored wastewater treatment. Experiments were conducted on water solutions of four different organic dyes, two azo dyes C.I. Mordant Yellow 10 (MY10) and C.I. Direct Orange 39 (DO39), and two reactive of azo type C.I. Reactive Red 45 (RR45) and C.I. Reactive Blue 137 (RB137). The efficiency of studied AOPs has been estimated on the bases of UV–vis spectrophotometric and TOC measurements. The rate constants in the kinetic model have been determined. Experimental data have been compared with the developed mathematical model.

Inactivation of Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes by underwater shock waves

Underwater shock waves are pressure discontinuities generated by means of high voltage electric discharges in water. Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes were exposed to shock waves. The influence of the pulse of light produced by the electric discharge, acoustic cavitation produced by the shock waves, the phase of growth and shock wave dosage on bacteria inactivation was evaluated. Inactivation of bacteria by shock waves ranged from 0 to 3.18 log 10 CFU/ml. L. monocytogenes was the most susceptible microorganism, 3.17 log 10 CFU/ml inactivation was achieved with 350 shock waves. At the same shock wave dosage, 1.68 log 10 CFU/ml and 0.56 log 10 CFU/ml inactivation was achieved for S. Typhimurium and E. coli O157:H7, respectively. Even if the achieved inactivation still is of little practical value, higher shock wave energy may enhance bactericidal activity. The analysis of variance revealed that synergy between light and the other factors contributed to bacterial inactivation. Differences in the response of bacteria, along with data analysis, suggest different mechanisms of inactivation by shock waves. Industrial relevance: Underwater shock waves generated via high voltage electric discharge or the use of explosives have been reported for microbial inactivation and for softening of animal tissue. The current paper deals with the interaction of underwater shock waves, the associated cavitation and pulse of light generated in the UV and visible spectra. Although the data generated don't show spectacular microbial inactivation, systematic studies like this can lead to the development of new combination processes with specific applications (e.g., microbial inactivation within containers).

The Application of High-Power Sound Waves for Wellbore Cleaning

SummaryThis paper presents the results of a wide-ranging investigation into the application of high-power sound waves to remove plugging material from the wellbore and near-wellbore regions. This paper describes the process of generating high-power sound waves with a high-voltage electrical discharge and summarizes the results of the laboratory and test-well trials conducted on both simulated plugging materials and mudcake. The paper also references the development progress of a prototype wireline-conveyed, wellbore-cleaning system. The results of the investigation concluded that high-power sound waves represent a viable wellbore-cleaning technology with the potential to be applied effectively in removing various forms of wellbore-plugging material. Because this process can be applied selectively and in a controlled manner in the wellbore, without environmental impact and with standard wireline-deployment techniques, it offers considerable benefits vs. some existing solutions.

Towards an Alternative Extraction Process for Linseed Oil

Industrial linseed oil is obtained after crushing, cooking, expression and solvent extraction. Our objective was to develop an extraction process in which solvent use was excluded or minimized. In addition to that, in order to preserve the functionalities of cake proteins, a maximum temperature of 50°C was imposed throughout the process. As these two restrictive conditions decrease dramatically the oil yield, enzymatic and electric treatments were considered. Oil yields similar to those obtained by expression at 100°C were achieved by optimizing the crushing conditions. Alternatively, with expression, a high-efficiency enzymatic treatment was tested on crushed and humidified seeds. By this enzymatic liquefaction, an extremely stable emulsion was produced due to the mucilage present in the seeds, which is a good natural emulsifier. In order to separate oil from water, it is necessary to eliminate the mucilage before the enzymatic treatment. Two methods of aqueous extraction were tested: one at 34°C under agitation and the other enhanced by high voltage electrical discharges. The second process proved to be of greater efficiency. To sum up, the new process comprises the following stages: crushing, expression, demucilagination by electric discharges, centrifugal separation of mucilage and solid residue, enzymatic or electric treatment of this residue and final separation of oil, water and solid fractions.

Raman study of aqueous sodium nitrate, activated by the high-voltage pulsed electric discharge

Raman spectra of a saturated aqueous solution of sodium nitrate (NaNO 3/H 2O) in the region of the totally symmetric vibration ν 1( A) of the NO 3 − anion has been studied. The high-voltage pulsed electric discharge effect (HPED activation) on the molecular relaxation in NaNO 3/H 2O has been investigated. The temperature dependences of the width and frequency of the corresponding spectral line are examined. The transition of NaNO 3/H 2O from the normal state to the activated state under HPED effect is observed. The activated state of NaNO 3/H 2O is nonequilibrium and metastable.

610 高電圧放電を用いた燃料噴霧に放電エネルギが与える影響

610 高電圧放電を用いた燃料噴霧に放電エネルギが与える影響

Pulsed high voltage electric discharge disinfection of microbially contaminated liquids

To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

A Device for Ozone Production and Deactivation of Smoke Gases Based on an Electric Discharge Developing in the Runaway-Electrons Mode

A device for ozone production and deactivation of smoke gases has been designed. It is based on a high-voltage nanosecond electric discharge developing in the mode of runaway electrons at atmospheric pressure. The first experiments have shown high efficiency in the device operation. The specific energy consumption in the ozone production was 3.3 × 107 J/kg. Purification from smoke requires an energy consumption of 1.3 × 10–18 J per molecule of sulphur dioxide at a 50% degree of purification. Improvement of the device is planned.