High Voltage Electrical Discharges Research Articles

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.

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

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.

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.

Effects of High Voltage Electrical Discharge (HVED) on Endogenous Hormone and Polyphenol Profile in Wheat.

High voltage electrical discharge (HVED) is an eco-friendly low-cost method based on the creation of plasma-activated water (PAW) through the release of electrical discharge in water which results in the formation of reactive particles. Recent studies have reported that such novel plasma technologies promote germination and growth but their hormonal and metabolic background is still not known. In the present work, the HVED-induced hormonal and metabolic changes were studied during the germination of wheat seedlings. Hormonal changes including abscisic acid (ABA), gibberellic acids (GAs), indol acetic acid (IAA) and jasmonic acid (JA) and the polyphenol responses were detected in the early (2nd day) and late (5th day) germination phases of wheat as well as their redistribution in shoot and root. HVED treatment significantly stimulated germination and growth both in the shoot and root. The root early response to HVED involved the upregulation of ABA and increased phaseic and ferulic acid content, while the active form of gibberellic acid (GA1) was downregulated. In the later phase (5th day of germination), HVED had a stimulatory effect on the production of benzoic and salicylic acid. The shoot showed a different response: HVED induced the synthesis of JA_Le_Ile, an active form of JA, and provoked the biosynthesis of cinnamic, p-coumaric and caffeic acid in both phases of germination. Surprisingly, in 2-day-old shoots, HVED decreased the GA20 levels, being intermediate in the synthesis of bioactive gibberellins. These HVED-provoked metabolic changes indicated a stress-related response that could contribute to germination in wheat.

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.

Reactive phosphorus via simulated lightning discharge: A role for fulgurites in pre-biotic chemistry

Apatite is the most common phosphorus-bearing mineral in primary igneous rocks. Despite its early and ubiquitous presence in such rocks at the Earth's surface, its phosphorus exhibits a low reactivity in prebiotic chemosynthesis. This situation may change radically upon the transformation of phosphorus from orthophosphates to pyrophosphates or phosphides which are, in contrast, highly reactive in such scenarios. Pyrophosphates and phosphides are today however, scarce on Earth, generally not being stabilized in rock-forming processes. Noticeable exceptions are lightning-struck rocks (i.e., fulgurites). Here, we present the first evidence of reactive phosphorus (P) in a fulgurite which has been experimentally generated under controlled conditions from natural apatite. Crushed apatite was transformed into a fulgurite through the application of controlled high voltage electrical discharges. We document both the apatite (pre-experiment) and the fulgurite (post-experiment) texture, state, and chemistry. 31P and 19F nuclear magnetic resonance spectroscopy reveals the presence of a reactive P phase (pyrophosphate) in the fulgurite. Our results support the speculation that frequent lightning activity under early Earth conditions may have provided more than 100–10.000 kg/yr of reactive P on early Earth through the generation of reactive P-bearing fulgurites. Their presence may have enabled the chemosynthesis of vital prebiotic components such as RNA and lipids for the emergence of life on Earth.

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.

High Voltage Electric Pulse Drilling: A Study of Variables through Simulation and Experimental Tests

With the deepening of drilling depth, the difficulty of drilling engineering increases gradually due to the complex geological conditions. The traditional mechanical drilling method shows the problems of high energy consumption, low efficiency, long cycle and high cost. Because of the characteristics of rock, the high abrasiveness of rock causes great wear to the bit, which becomes an important factor affecting the drilling rate. High voltage electric pulse (Abbreviated as HVEP later in this paper) drilling technology is a new technology developed in the past several decades. The technology uses plasma channel, water jet or shock wave generated by high voltage electric pulse discharge to break rock. It has the characteristics of environmental protection, directional breaking, easy control of rock breaking process and fast speed in the face of complex hard rock. In this paper, the mechanism and technology of rock breaking by high voltage electric pulse method in deep drilling are studied, and the functional test is carried out.

Degradation of herbicide atrazine in water by high voltage electrical discharge in comparison with Fenton oxidation and ultrasound treatments

Compared to ultrasounds and Fenton oxidation, the degradation of atrazine by high-voltage electrical discharge has more advantages as: low toxicity of generated products, destruction of triazine ring, high degradation rate, energy and time saving.

Evaluation of the antimicrobial effects of Capsicum, Nigella sativa, Musa paradisiaca L., and Citrus limetta: A review

The extensive use of antibiotics and vaccines against microbial infections can result in long-term negative effects on humans and the environment. However, there are a number of plants that have antimicrobial effects against various disease-causing microbes such as bacteria, viruses, and fungi without negative side effects or harm to the environment. In this regard, four particular plants- Capsicum, Nigella sativa, Musa paradisiaca L., and Citrus limetta have been widely considered due to their excellent antimicrobial effect and ample availability. In this review, we discuss their antimicrobial effects due to the presence of thymoquinone, p-cymene, pinene, alkaloids, limonene, camphene, and melanin. These antimicrobial compounds disrupt the cell membrane of microbes, inhibit cellular division, and form biofilm in bacterial species, eventually reducing the number of microbes. Extraction of these compounds from the respective plants is carried out by different methods such as soxhlet, hydro-distillation, liquid-liquid extraction (LLE), pressurized liquid extraction (PLE), solid-phase extraction (SPE), supercritical fluid extraction (SFE), pulsed electric field (PEF), microwave-assisted extraction (MAE), enzyme-assisted extraction (EAE), ultrasound-assisted extraction (UAE), and high-voltage electrical discharge. Suitable selection of the extraction technique highly depends upon the associated advantages and disadvantages. In order to aid future study in this field, this review paper summarizes the advantages and disadvantages of each of these approaches. Additionally, the discussion covers how antimicrobial agents destroy harmful bacteria. Thus, this review offers in-depth knowledge to researchers on the antibacterial properties of Capsicum, Nigella sativa, Musa paradisiaca L. peels, and Citrus limetta.

Preliminary Study on the Impact of Non-Thermal Plasma Activated Water on the Quality of Triticum aestivum L. cv. Glosa Sprouts

The present study aimed to investigate the effects of non-thermal plasma-activated water (PAW) on Triticum aestivum L. cv. Glosa sprouts. Two types of PAW were generated by exposing distilled water to a high-voltage electric discharge. Wheat caryopses were treated either with PAW1 (25 mg/L NO3−, 4 mg/L NO2−, and 6 mg/L H2O2) or PAW2 (35 mg/L NO3−, 5 mg/L NO2−, and 7.5 mg/L H2O2) for 8 days, with samples being collected at days 1, 2, 3, and 8. The germination rate, growth parameters, protein, photosynthetic pigments, total phenolic contents, antioxidant activity of free and bound phenolic fractions, and activity of antioxidant enzymes were evaluated. Both PAW1 and PAW2 had positive effects on Triticum aestivum L. cv. Glosa sprouts. PAW2 had a better impact on sprouts with respect to growth parameters, free phenolic content, and antioxidant activity of the free phenolic fraction (day 3), the accumulation of proteins, and photosynthetic pigments (day 8). In conclusion, exposure to PAW increases the quality of Triticum aestivum L. cv. Glosa sprouts. Further optimization of PAW treatment is required for the most favorable impact on the accumulation of biomass and health-promoting compounds in sprouts.

Exploiting Virgin Olive Oil By-products Using Hydrodistillation

Virgin olive oil processing results in a large amount of biomass (leaves, pomace, stones and wastewater) during harvesting, pruning and production. In recent years, these by-products have been studied as possible sources of bioactive compounds, and several techniques have been developed, including microwave, ultrasound, subcritical extraction, high hydrostatic pressure, a pulsed electric field, and high-voltage electrical discharge. However, these techniques can be expensive, and may require specialized staff to implement them. Therefore, this study proposes a novel method. Hydrodistillation is a simple and fast technique that can recover valuable compounds from olive oil biomasses. As it uses water as a solvent, it is sustainable, does not harm the environment, and is compatible with industrial practice. This paper presents the results of a hydrodistillation experiment on olive leaves, olive pomace and olive stones. Two fractions were obtained: a “phytocomplex” fraction from inside the boiler, and a “hydrolate” fraction from inside the condenser column. HPLC–DAD–MS and GC–MS analyses characterized and differentiated these two fractions. In general, more bioactive compounds, notably phenolic, were recovered from the phytocomplex fraction than the hydrolate fraction. Total phenolic compounds (mgtyr/kgoil) in the phytocomplex fraction were 11903.51, 4007.33, and 2469.42 mgtyr/kgoil for olive leaves, olive pomace and olive stone, while in the hydrolate fraction they were 67.67, 1.98, and 29.05 mgtyr/kgoil, respectively. Furthermore, interesting phenolic compounds typical of Olea europaea L. were found for both matrices. The main families were phenolic alcohols, secoiridoids and flavonoids. In particular, oleuropein, hydroxytyrosol, and tyrosol were recovered from the phytocomplex fraction of leaves and pomace. Finally, the analysis revealed higher amounts of volatile compounds in the hydrolate fraction than the phytocomplex fraction for leaves, stone and pomace. The main class of compounds were esters, ketones, aldehydes, alcohols, terpenes, phenols and their derivatives.Graphical

Study on High-Strain-Rate Deformation of Magnesium Alloy Using Underwater Shock Waves Generated by High-Voltage Electric Discharge of Thin Wire

Magnesium is an abundant material with high specific strength, and its use as a structural metal is increasing. However, its properties cause difficulty in its formation at room temperature. Therefore, the objective of this study was to form a magnesium alloy at room temperature using an underwater shock wave generated by the discharge of an aluminum wire. Forming was conducted using an auxiliary plate composed of aluminum instead of magnesium alloy alone. In addition, hyperbolic and parabolic pressure vessels were employed. Numerical simulations were performed to measure the pressure values, propagation of underwater shock waves, and deformation of the magnesium alloy. Large deformation was observed when an auxiliary aluminum plate was placed on the upper surface of an AZ31 magnesium alloy plate inside the hyperbolic pressure vessel.

Testing of a new high voltage electrical discharge generator prototype at high frequencies to assist anthocyanin extraction from blueberries

Traditional extraction methods are based on high-temperature maceration with organic solvents, which are dangerous for human health. A viable alternative to overcome the issues associated with conventional extraction is to increase cell tissue permeability by applying high voltage electrical discharge (HVED) treatments. The objective of this work was to validate the electroporation of blueberry plant cells using a new HVED generator prototype at a high frequency, investigate the effect, intensity, and duration of the applied voltage, and recover anthocyanins from its electroporated cells. The electroporation level of the HVED-treated blueberries was measured qualitatively by transmission electron microscopy (TEM) analysis. Meanwhile, it was quantitatively measured by the cell permeabilization index (Zp) and anthocyanin extraction level. Results of the micrographs (TEM) showed electroporation in all treatments in which Zp was 0.24 when applying a 2 kV treatment for 2 s, whereas a 3-fold increase in tissue damage was revealed with the most powerful treatment (10 kV voltage, 30 s). In addition, anthocyanin values ranged from 83.09 ± 1.20 (control) to 136.82 ± 0.84 (HVED), which was 64.66% higher. The HVED treatment can increase mass transfer rates during conventional extraction processes. It should be noted that the validated prototype required a low specific energy requirement (31–204 kJ/kg) for proper tissue electropermeabilization. In conclusion, we demonstrated the capability of the developed HVED prototype to boost mass transfer phenomena and thus potentially increase its adaptability to assist dissimilar industrial processes or waste (e.g., peels and seeds) such as freeze-drying operations.

ИСПОЛЬЗОВАНИЕ ЛАЗЕРНОГО ИМПУЛЬСНОГО ИЗЛУЧЕНИЯ И РАСТВОРОВ ЭКОПЕРОКСИДА ДЛЯ АКТИВАЦИИ СЕМЯН САХАРНОЙ СВЕКЛЫ

Sugar beet, a biennial industrial agricultural crop, is used for the production of ethanol, biofuels, sugar and contains up to 70% sucrose. It is difficult to obtain seeds, the collection of which takes place in the second year of cultivation of root crops. The possibility of accelerating seed activation, increasing germination by methods of pre-sowing treatment of dry seeds: laser pulsed radiation and ecoperoxide solutions was studied. The first test indicating the beginning of seed awakening (one hour after treatment) was a test for determining the release of metabolites into the aqueous culture medium. The metabolites determined by spectrophotometry. They have a characteristic absorption spectrum in the UV region with a clear maximum at λmax – 207 nm and absorption up to the boundary with the visible region of 
 λmax – 330 nm. A copper vapor laser was used. Parameters: simultaneous generation of two wavelengths – green 510.5 nm and yellow 578.2 nm. The duration of the radiation pulse is 15 ns, the repetition rate is 10 kHz. The irradiation time is 10, 20, 90 s. The greatest effect of seed germination stimulation at 10 s of irradiation exceeded the control by 30%. Increasing the interval to 24 hours or more between irradiation and placing seeds for germination reduced the number of germinated seeds. Ecoperoxide was obtained by high-energy non-contact exposure to distilled water with high-voltage electric discharge streamers. An increase in seed germination by 30-40% was noted when they came into contact with a peroxide solution for 30 minutes.

High-voltage electric discharge as pretreatment for efficient extraction of bioactive compounds from red onion peel

The outer skins of onions are rich in various functional compounds, and the extraction of phytonutrients is one of the most critical steps during their processing. The effects of the energy (12.5–50 J/mL) and the liquid/solid ratio (30–60) were investigated using a central composite design (CCD). It was observed that an increment in energy input caused a steep rise in total phenol content. On the other hand, as the L/S ratio increased, the anthocyanin content decreased dramatically. At lower L/S ratios, the DPPH scavenging activity peaked after increasing the energy input. Optimum conditions were determined as the energy input of 49.37 J/mL and the L/S ratio of 40. Scanning electron microscopy images demonstrated a severely ruptured cell wall structure during HVED extraction. The treated ROP extract completely prevented the growth of Pseudomonas aeruginosa colonies. The high extraction rate of total phenols and potent antibacterial activity highlight the excellent potential of HVED in extracting phytochemicals.

Термическое разложение дистиллята каменноугольной смолы в присутствии нанопорошка железа

Impact of the nanosized iron powder on the process of thermal degradation of coal tar distillate was determined by the thermogravimetric analysis. Coal tar distillate was obtained by simple distillation up to 350°C of primary coal tar from the Shubarkol deposit. Iron powder was obtained by electrochemical reduction of iron from sulfate electrolytes at simultaneous impact of high-voltage electric discharge on cathodic zone. Scanning electron microscopy showed that iron powder consists of nanosized particles (30-124 nm) forming aggregates. X-ray diffraction analysis revealed the presence of α-Fe and FeO(OH) phases. The average crystallite size determination was made using Scherrer equation and amounted to 31.7 nm. Obtained iron powder was added to the coal tar distillate in amount of 1% of distillate weight and this mixture was subjected to thermal degradation at heating rate 5°C/min in an inert atmosphere. Processing of the data obtained was carried out using the model-fitting Coats-Redfern method. The values of activation energy were calculated from the linear approximation constructed as a result of processing thermoanalytical data. It was found that the addition of iron powder in amount of 1% to the coal tar distillate reduces the activation energy from 153.98 kJ/mol to 84.48 kJ/mol.

Physical Properties of Starches Modified by Phosphorylation and High-Voltage Electrical Discharge (HVED).

High-voltage electrical discharge (HVED) is considered as a novel, non-thermal process and is currently being researched regarding its effect on microorganisms (decontamination of food), waste water treatment, and modification of different compounds and food components. In this paper, four native starches (maize, wheat, potato, and tapioca) were treated with HVED, phosphorylated with Na2HPO4 and Na5P3O10, and modified by a combination of HVED with each phosphorylation reaction both prior and after chemical modification. Pasting properties, swelling power, solubility, gel texture, and particle size were analyzed. Although HVED induced lower contents of P in modified starches, it had an effect on analyzed properties. The results revealed that HVED treatment alone had a limited effect on pasting properties of starches, but it had an effect on properties of phosphorylated starches, both when it was conducted prior and after the chemical modification, reducing the influence of Na5P3O10 and Na2HPO4 on the decrease of pasting temperature. With minor exceptions, the gel strength of starches increased, and the rupture strength decreased by all modifications. HVED treatment resulted in a decrease of the particle size after the modification of maize and wheat starches, while potato and tapioca starches were not significantly influenced by the treatment.