Bibliografie tematiche / High voltage electrical discharge (HVED)

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Letteratura scientifica selezionata sul tema "High voltage electrical discharge (HVED)"

Autore: Grafiati

Pubblicato: 10 agosto 2024

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Articoli di riviste sul tema "High voltage electrical discharge (HVED)"

Gryszkin, Artur, Marijana Grec, Đurđica Ačkar, Tomasz Zięba, Antun Jozinović, Drago Šubarić, Borislav Miličević, Marijana Blažić e Jurislav Babić. "Phosphorylation of Maize Starch Enhanced with High-Voltage Electrical Discharge (HVED) Instead of Thermal Treatment". Polymers 13, n. 19 (23 settembre 2021): 3231. http://dx.doi.org/10.3390/polym13193231.

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The aim of this research was to explore the use of a high-voltage electrical treatment (HVED) as a substitute for heating during the phosphorylation of maize starch. Starch was treated with HVED, phosphorylated with Na2HPO4 or Na5P3O10 with and without thermal treatment and phosphorylated in combination with HVED prior to and after the chemical modification. When starch was phosphorylated with Na2HPO4, HVED was more efficient in catalyzing reaction (3.89 mg P/kg for 30 min HVED in relation to 0.43 mg P/kg for thermal treatment), whereas with Na5P3O10 similar P content was achieved as with thermal treatment (0.76 P/kg for 30 min HVED in relation to 0.86 mg P/kg). The order of HVED and chemical reactions did not have a marked effect on phosphorous content. In combination with Na2HPO4, HVED pre-treatment had a more pronounced effect on the solubility and water absorption, whereas post-treatment was favoured with Na5P3O10. Mean diameter was increased by all treatments, where HVED had a marked effect. Enthalpy of gelatinization ranged from 11.76 J/g for starch treated with Na5P3O10 and 10 min-HVED to 13.58 J/g for Na5P3O10 treated sample. G′ and G″ increased after both thermally and HVED enhanced phosphorylations, with a slightly more pronounced effect of the HVED.

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Lojková, Lea, Sanja Zec Zrinušić, Helena Pluháčková, Radim Cerkal e Tihana Marček. "The effect of high voltage electrical discharge (HVED) treatment on small seed plants". Croatian journal of food science and technology 16, n. 1 (19 giugno 2024): 45–55. http://dx.doi.org/10.17508/cjfst.2024.16.1.04.

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The High Voltage Electrical Discharge (HVED) is a physical hydropriming method which alters the physicochemical properties of water, creating the plasma activated water (PAW). The mixture of highly reactive ions and molecules can break down the seed dormancy and speed up the growing process. Previous studies presented the promotional role of HVED technology on the germination, growth and polyphenol content. The aim of this study was to explore the effect of HVED technology on germination ability and vitality of three types of seeds with low germination rate. Selected species included carrot (Daucus carota L.), melilot (Melilotus albus Medik.), and mallow (Malva verticillata L.). In carrot and mallow, HVED (20Hz/30s) significantly promoted germination percentage, whilst in melilot seeds, germination was unchanged. HVED treatment enhanced the growth of shoots and roots in both carrot and mallow. In melilot, shorter treatment time of exposure to high voltage (30Hz/10s) resulted in longer shoots and roots. Perspectives of HVED as a method for improvement of germination exist, especially in mellow and carrot, but it is necessary to optimize the process parameters for each type of seed separately.

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Ačkar, Đurđica, Marijana Grec, Ivanka Grgić, Artur Gryszkin, Marzena Styczyńska, Antun Jozinović, Borislav Miličević, Drago Šubarić e Jurislav Babić. "Physical Properties of Starches Modified by Phosphorylation and High-Voltage Electrical Discharge (HVED)". Polymers 14, n. 16 (17 agosto 2022): 3359. http://dx.doi.org/10.3390/polym14163359.

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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.

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Marček, Tihana, Kamirán Áron Hamow, Tibor Janda e Eva Darko. "Effects of High Voltage Electrical Discharge (HVED) on Endogenous Hormone and Polyphenol Profile in Wheat". Plants 12, n. 6 (8 marzo 2023): 1235. http://dx.doi.org/10.3390/plants12061235.

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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.

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Marček, Tihana, Tihomir Kovač, Katarina Jukić, Ante Lončarić e Maja Ižaković. "Application of High Voltage Electrical Discharge Treatment to Improve Wheat Germination and Early Growth under Drought and Salinity Conditions". Plants 10, n. 10 (9 ottobre 2021): 2137. http://dx.doi.org/10.3390/plants10102137.

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The environmentally friendly, physical method of high voltage electrical discharge (HVED) was developed to improve the drought and salinity tolerance of two wheat genotypes. Unlike other plasma technologies, HVED treatment involves the discharge of electricity in water. In this study, the effect of HVED pretreatment on wheat germination and early vegetative growth under drought (0%, 15%, 20% and 30% PEG) and salinity (0, 90, 160 and 230 mM NaCl) stress conditions was investigated. HVED-exposed seeds showed altered seed surfaces and became more permeable to water uptake, resulting in higher germination percentages, germination index values, and shoot and root growth under the control and all drought and salinity concentrations. Moreover, the electrical conductivity of the water medium increased significantly, indicating HVED-induced reactions of ionization and dissociations of water molecules occurred. In addition, HVED pretreatment in the salt experiment improved the tolerance index values of the shoots and roots. The most pronounced genotypic variations occurred under the highest stress levels (30% PEG or 230 mM NaCl) and varied with the stress intensity and growth stage. The study results indicate that HVED pretreatment has the potential to improve drought and salt tolerance in wheat.

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Tomašević, Marina, Karin Kovačević Ganić, Katarina Lukić, Natka Ćurko, Tomislava Vukušić e Stela Križanović. "Potential application of high voltage electrical discharge plasma control of Brettanomyces bruxellensis in wine". Glasnik zaštite bilja 42, n. 5 (31 ottobre 2019): 54–60. http://dx.doi.org/10.31727/gzb.42.5.6.

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The aim of this work was to investigate the effect of high voltage electrical discharge (HVED) plasma on inactivation of Brettanomyces bruxellensis yeast in red wine. Research was conducted in two phases. Firstly, the efficacy of two main plasma parameters was examined - frequency (60, 90 and 120 Hz) and treatment duration (3, 5, 10, 20 and 30 min). Second phase included monitoring long-term effect of HVED plasma using optimal frequency during selected treatment durations, where culturability of B. bruxellensis was determined after 30, 60 and 90 days of storage. Results show that frequency of 120 Hz caused slightly higher inactivation than the lower ones. Furthermore, longer treatment durations resulted in significantly higher inactivation, wherein the treatment of 30 min showed the best results. Finally, during storage period, the inactivation effect of HVED plasma was reversed and B. bruxellensis yeast recovered almost completely in treated wine.

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Barišić, Veronika, Ivana Flanjak, Mirela Kopjar, Mirta Benšić, Antun Jozinović, Jurislav Babić, Drago Šubarić et al. "Does High Voltage Electrical Discharge Treatment Induce Changes in Tannin and Fiber Properties of Cocoa Shell?" Foods 9, n. 6 (19 giugno 2020): 810. http://dx.doi.org/10.3390/foods9060810.

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Cocoa shell is a by-product of the chocolate industry that is rich in dietary fiber and bioactive components. In this research, the influence of high voltage electric discharge (HVED) treatment on chemical and physical characteristics of the cocoa shell, i.e., the effects of applied time and frequencies on grinding ability, water binding capacity (WBC), dietary fibers and tannin content was investigated. HVED had a significant influence on the chemical and physical properties of cocoa shell, all of which could be linked to changes in fiber properties. Along with the fiber content, grinding ability and water binding capacity were increased. These properties have already been linked to fiber content and soluble/insoluble fiber ratio. However, this research implies that change in fiber properties could be linked to tannin formation via complexation of other polyphenolic components. Additional research is needed to verify this effect and to establish mechanisms of tannin formation induced by HVED and its influence on fiber quantification.

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Tiban, Nela Nedić, Mirela Šimović, Martina Polović, Antonija Šarić, Ivana Tomac, Petra Matić e Lidija Jakobek. "The Effect of High Voltage Electrical Discharge on the Physicochemical Properties and the Microbiological Safety of Rose Hip Nectars". Foods 11, n. 5 (23 febbraio 2022): 651. http://dx.doi.org/10.3390/foods11050651.

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Although neglected as an industrial raw material, rose hip has been important for both nutritional and medical purposes for centuries. The main goal of this study was to propose a rapid and inexpensive non-thermal technique such as high voltage electrical discharge (HVED) to preserve valuable rose hip bioactive compounds, towards the development of high-quality products, including low-calorie products. The objective of this work was to evaluate the effects of HVED on the physicochemical properties and the microbiological safety of rose hip nectar formulations and, for comparison, on a pasteurised sample. Physicochemical analysis proved that rose hip pulp and the prepared nectars were valuable sources of polyphenols and ascorbic acid with high antioxidant activity. The HVED technique had minimal effects on the quality characteristics of the nectars under the different process conditions (50, 100 Hz; 10, 15, 20 min). In addition, the pasteurised nectar showed the greatest loss of ascorbic acid (54%) and phenolic compounds (40%). The microbiological quality of nectars was examined immediately after preparation/treatment and after 6 and 12 days of storage at 4 °C. In addition to the pasteurised sample, HVED-treated rose hip nectar prepared from microwave-blanched puree with extended shelf life had satisfactory microbiological safety after storage.

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Nutrizio, Marinela, Jasenka Gajdoš Kljusurić, Zvonimir Marijanović, Igor Dubrović, Marko Viskić, Elena Mikolaj, Farid Chemat e Anet Režek Jambrak. "The Potential of High Voltage Discharges for Green Solvent Extraction of Bioactive Compounds and Aromas from Rosemary (Rosmarinus officinalis L.)—Computational Simulation and Experimental Methods". Molecules 25, n. 16 (14 agosto 2020): 3711. http://dx.doi.org/10.3390/molecules25163711.

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Rosemary (Rosmarinus officinalis L.) is a Mediterranean medicinal and aromatic plant widely used due to valuable bioactive compounds (BACs) and aromas. The aim of the study was to evaluate the extraction of intracellular compounds from rosemary combining experimental procedure by means of high voltage electrical discharge (HVED), with a theoretical approach using two computational simulation methods: conductor-like screening model for real solvents and Hansen solubility parameters. The optimal HVED parameters were as follows: frequency 100 Hz, pulse width 400 ns, gap between electrodes 15 mm, liquid to solid ratio 50 mL/g, voltage 15 and 20 kV for argon, and 20 and 25 kV for nitrogen gas. Green solvents were used, water and ethanol (25% and 50%). The comparison was done with modified conventional extraction (CE) extracted by magnetic stirring and physicochemical analyses of obtained extracts were done. Results showed that HVED extracts in average 2.13-times higher total phenol content compared to CE. Furthermore, nitrogen, longer treatment time and higher voltage enhanced higher yields in HVED extraction. HVED was confirmed to have a high potential for extraction of BACs from rosemary. The computational stimulation methods were confirmed by experimental study, ethanol had higher potential of solubility of BACs and aromas from rosemary compared to water.

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Žuntar, Irena, Predrag Putnik, Danijela Bursać Kovačević, Marinela Nutrizio, Filip Šupljika, Andreja Poljanec, Igor Dubrović, Francisco Barba e Anet Režek Jambrak. "Phenolic and Antioxidant Analysis of Olive Leaves Extracts (Olea europaea L.) Obtained by High Voltage Electrical Discharges (HVED)". Foods 8, n. 7 (8 luglio 2019): 248. http://dx.doi.org/10.3390/foods8070248.

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Background: The aim of this study was to evaluate high voltage electrical discharges (HVED) as a green technology, in order to establish the effectiveness of phenolic extraction from olive leaves against conventional extraction (CE). HVED parameters included different green solvents (water, ethanol), treatment times (3 and 9 min), gases (nitrogen, argon), and voltages (15, 20, 25 kV). Methods: Phenolic compounds were characterized by ultra-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS), while antioxidant potency (total phenolic content and antioxidant capacity) were monitored spectrophotometrically. Data for Near infrared spectroscopy (NIR) spectroscopy, colorimetry, zeta potential, particle size, and conductivity were also reported. Results: The highest yield of phenolic compounds was obtained for the sample treated with argon/9 min/20 kV/50% (3.2 times higher as compared to CE). Obtained results suggested the usage of HVED technology in simultaneous extraction and nanoformulation, and production of stable emulsion systems. Antioxidant capacity (AOC) of obtained extracts showed no significant difference upon the HVED treatment. Conclusions: Ethanol with HVED destroys the linkage between phenolic compounds and components of the plant material to which they are bound. All extracts were compliant with legal requirements regarding content of contaminants, pesticide residues and toxic metals. In conclusion, HVED presents an excellent potential for phenolic compounds extraction for further use in functional food manufacturing.

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Più fonti

Tesi sul tema "High voltage electrical discharge (HVED)"

Hong, Junting. "Evaluation of atrazine degradation processes in water by electrical discharges and high-frequency ultrasound : parametric optimization and study of reaction mechanisms". Electronic Thesis or Diss., Compiègne, 2024. http://www.theses.fr/2024COMP2804.

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L'objectif principal de la thèse est de développer une technologie efficace pour la dégradation des pesticides. L'herbicide atrazine a été étudié comme molécule modèle. L'atrazine a été dégradée dans l'eau par décharge électrique de haute tension (DEHT), et ses performances de dégradation ont été comparées aux technologies traditionnelles d'oxydation de Fenton et d'ultrasons (US). La détection et la quantification de l'atrazine et de ses métabolites ont été réalisées par chromatographie liquide haute performance et spectrométrie de masse à haute résolution (HPLC-HRMS). Une méthode d'analyse en ligne par HPLC-HRMS combinée à un échantillonnage automatique a été développée pour un suivi en temps réel du processus de dégradation. La technologie DEHT a dégradé efficacement l'atrazine et a réduit les métabolites toxiques générés au cours des processus d’oxydation de Fenton et d’US. Le procédé de DEHT est moins consommateur d'énergie que le procédé d’US tout en atteignant la même efficacité de dégradation de l'atrazine de 89%. Les mécanismes de dégradation de l'atrazine pour les différentes technologies ont été proposés. L'effet d'une matrice réelle (eau du robinet) par rapport à une matrice modèle (eau déminéralisée) sur la dégradation de l'atrazine a été étudié. Les résultats ont montré que dans le cas d’un traitement par DEHT, l'efficacité de dégradation de l'atrazine dans l'eau du robinet était inférieure à celle de l'eau déminéralisée, ce qui peut être lié à la conductivité de l'eau et au mécanisme de génération des arcs électriques dans un milieu conducteur. La toxicité aiguë (CL50) chez la daphnie Daphnia magna a été utilisée pour évaluer la toxicité des différentes solutions de traitement contenant initialement de l'atrazine. La toxicité de la solution d'atrazine traitée par oxydation de Fenton est supérieure à celle traitée par DEHT et US
The main goal of this thesis is to develop an efficient technology for the degradation of pesticides. For this purpose, the widely used herbicide atrazine was studied as a model molecule. Atrazine was degraded in water by high voltage electrical discharge (HVED), and its degradation performance was compared with traditional water treatment technologies Fenton oxidation and ultrasound (US). The detection and quantification of atrazine and its metabolites were achieved by high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS). An online analysis method by HPLC-HRMS combined with automatic sampling was developed for real-time monitoring of the degradation process. The HVED technology efficiently degraded atrazine and reduced toxic metabolites generated during Fenton oxidation and US processes. HVED process has less energy consumption than US process while achieving the same 89% atrazine degradation efficiency. The mechanism pathways of atrazine degradation for different technologies were proposed. The effect of real matrix (tap water) versus model matrix (deionized water) on atrazine degradation was studied. Results showed that in HVED treatment, the degradation efficiency of atrazine in tap water was lower than that in deionized water, which may be related to the conductivity of the water and to the mechanism of electric arcs generation in a conductive medium. The acute toxicity (LC50) in Daphnia magna was used to evaluate the toxicity of different treatment solutions initially containing atrazine. The toxicity of atrazine solution treated by Fenton oxidation is higher than that treated by HVED and US

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Zhang, Rui. "Impact of emerging technologies on the cell disruption and fractionation of microalgal biomass". Thesis, Compiègne, 2020. http://www.theses.fr/2020COMP2548.

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Ce travail de recherche se concentre sur l'extraction et le fractionnement des biomolécules à partir de microalgues par des traitements physiques: les champs électriques pulsés (CEP), les décharges électriques de hautes tensions (DEHT) et les ultrasons (US). Dans cette étude, trois espèces de microalgues Nannochloropsis sp., Phaeodactylum tricornutum (P. tricornutum) et Parachlorella kessleri (P. kessleri) ont été étudiées. Les espèces ont différentes formes cellulaires, structure et contenu intracellulaire. L'effet des techniques testées sur l'extraction des biomolécules a été mis en évidence à travers une analyse quantitative et qualitative: suivi du rendement des composés ioniques, des glucides, des protéines, des pigments et des lipides. Une étude comparative des traitements physiques (CEP, DEHT et US), à la même énergie, pour la libération des biomolécules intracellulaires à partir des trois espèces de microalgues, a permis de mieux comprendre les différents mécanismes de désintégration. Pour chaque microalgue, à la même énergie consommée, le traitement par DEHT s'est révélé le plus efficace en terme d'extraction des glucides, tandis que les US sont plus efficaces pour l'extraction des protéines et des pigments. Le traitement par CEP a été moins efficace en terme du rendement d’extraction. Cependant, la meilleure sélectivité (extraction des glucides) a été obtenue en utilisant les CEP ou les DEHT. Les prétraitements physiques (CEP, DEHT ou US) des suspensions plus concentrées suivis d'une homogénéisation haute pression (HHP) de suspensions diluées ont permis d'améliorer l'efficacité de l'extraction et de diminuer la consommation énergétique totale et le nombre de passages. Le prétraitement physique permet de réduire la pression mécanique de l’HHP, pour atteindre le même rendement d’extraction. Pour la valorisation maximale de la biomasse de microalgues, une procédure d'extraction assistée par DEHT (40 kV/cm, 1-8 ms) suivie de plusieurs étapes d'extraction aqueuses et non aqueuses semble être utile pour l'extraction sélective et le fractionnement de différentes biomolécules à partir de microalgues. Des effets significatifs du prétraitement HVED sur l'extraction par solvant organique des pigments (chlorophylles, caroténoïdes) et des lipides ont été observés
This research work focuses on extraction and fractionation of bio-molecules from microalgae using physical treatments: pulsed electric fields (PEF), high voltage electrical discharges (HVED) and ultrasonication (US) techniques. In this study, three microalgae species Nannochloropsis sp., Phaeodactylum tricornutum (P. tricornutum) and Parachlorella kessleri (P. kessleri) were investigated. These species have different cell shapes, structure and intracellular contents. The effects of tested techniques on extraction of bio-molecules have been highlighted in a quantitative and qualitative analysis by evaluating the ionic components, carbohydrates, proteins, pigments and lipids. A comparative study of physical treatments (PEF, HVED and US) at the equivalent energy input for release of intracellular bio-molecules from three microalgal species allowed us to better understand the different disintegration mechanisms. For each microalga at the same energy consumption, the HVED treatment proved to be the most efficient for extraction of carbohydrates, while the US treatment for extraction of proteins and pigments. In general, the smallest efficiency was observed for the PEF treatment. However, the highest selectivity towards carbohydrates can be obtained using the mild PEF or HVED technique. The preliminary physical treatments (PEF, HVED or US) of more concentrated suspensions followed by high pressure homogenization (HPH) of diluted suspensions allowed improving the extraction efficiency and decreasing the total energy consumption. The physical pretreatments permit to reduce the mechanical pressure of the HPH and number of passes, to reach the same extraction yield. For the maximum valorisation of microalgal biomass, extraction procedure assisted by HVED treatment (40 kV/cm, 1-8 ms) followed by aqueous and non-aqueous extraction steps seems to be useful for selective extraction and fractionation of different bio-molecules from microalgae. The significant effects of HVED pre-treatment on organic solvent extraction of pigments (chlorophylls, carotenoids) and lipids were also observed

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Christou, Ilias. "Optimisation of high voltage electrical systems for aerospace applications". Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/optimisation-of-high-voltage-electrical-systems-for-aerospace-applications(9b8c70c0-7c82-4191-9199-bb05360f1b40).html.

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Increased electrical power demands are being experienced on the new generation of aircraft due to an increased reliance on electrical technology of systems such as air conditioning, de-icing systems and electrical flight control actuation. Distribution of power at higher AC and DC voltages is therefore now being seen in modern aircraft to avoid the penalties incurred due to high cable weights. Voltages have increased past the minimum of Paschen's law resulting in a risk that life limiting partial discharge (PD) damage can occur in the insulation systems. This thesis uses a theoretical analysis backed by PD experimental results to investigate the optimal operating voltage of a cabling system. In addition, it proposes a methodology for optimizing the operating voltage level based on an analysis of the power carrying capability of cabling within a fixed and a non-fixed volume system and the derivation of the cable weight as a function of voltage. Furthermore the power carrying capability of a certain round cable system is compared with an insulated flat conductor system as in a printed circuit board (PCB). An initial assessment has been carried out to determine whether more power can be delivered via insulated flat solid conductors as in a PCB, instead of using round cables. The reason why there is a need to investigate this aspect, is because using new PCB technology can offer several advantages over traditional cabling harnesses. The work done has shown that the optimal operating point (e.g. maximum power to weight ratio) for an aircraft power system, does not improve after certain voltage levels. A tradeoff between cable weight and power transfer is required and furthermore the use of DC systems can result in higher power transfers than conventional three phase/400Hz AC systems. The PCB maximum power transfer assessment has also shown that insulated flat conductor systems can offer higher power transfer efficiencies. In addition, experimental AC and DC PD tests on certain unscreened aerospace cables (laid out in different configurations), have shown that the theoretical analysis employed to determine cable safe operating voltages gives conservative results.

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Gul, Ibrahim Oguz. "A New High Voltage Partial Discharge Indicator System". Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607263/index.pdf.

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In this thesis work, a new partial discharge magnitude indicator with LCD display was designed. This system was implemented in high voltage partial discharge detection and measurement systems. AVRISP In-System programmer is used to program the microprocessors used inside the display unit. The time resolution of the system (one pixel of the display unit) is 4 microseconds. The unit is capable of counting the number of impulses of the input voltage that is coming from the high voltage system within user selectable time intervals. The changeable values of the time intervals are 2, 4, 6, 8 and 10 seconds. It is also capable of showing the maximum value of the impulses in a given time interval. This maximum value is a number changing between 0 and 256. By calibration of the system, it was possible to indicate the discharge magnitudes in picocoulombs.

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Can, Muhiddin. "Thermo-mechanical behaviour of metal powders under high voltage electrical discharge". Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279581.

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Abd, Rahman M. S. "Identification of partial discharge sources and their location within high voltage transformer windings". Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/369418/.

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This thesis is concerned with developing a new approach to high voltage transformers condition monitoring, which involve partial discharge (PD) measurement and localisation within high-voltage transformer windings. This is an important source of information for both diagnosis and prognosis of the health of power transformers. Generally, Partial discharges (PDs) existence in transformer windings are normally due to ageing processes, operational over stressing or defects introduced during manufacture. Although, the presence of PDs does not necessarily indicate imminent failure of a transformer, it is however, a serious insulation degradation or ageing mechanism which can be considered as a precursor of transformer failure. The initial approach taken in this thesis is based on a lumped parameter network model. The model was created and its parameters were approximated using analytical solutions based on the geometrical dimensions of transformer windings. Based on the lumped parameter network model, theoretically the rational function should be a positive-real (PR) function and it is shown later on in this thesis that the model does hold the theoretical assumptions. Nevertheless, impulse response of actual transformer windings constructed for laboratory assessment was shown differently although different methods were used to find rational functions with positive-real (PR). Due to the fact that real transformer windings do not hold the characteristic of positive real transfer function, thus, this thesis finds an alternative and proposes a different approach for PD localisation which is based on energy distribution and features extraction methods for localisation, particularly Wavelet Transform (WT) and Principal Component Analysis (PCA). The idea of the developed approach is based on the fact that any discharge occurring at any point along windings produce an electrical signal that will propagate as a travelling wave towards both ends of the windings. During the propagation of the PD signals along transformer windings, the response with respect to the propagation path taken and termination characteristics will cause attenuation and distortion to the waveforms, ultimately produced changes in the energy characteristics of the PD pulses when they reach measurement sensors.

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Mohamed, Ramizi. "Partial discharge signal propagation, modelling and estimation in high voltage transformer windings". Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/165433/.

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The thesis concerns partial discharge (PD) propagation within a high voltage transformer winding. Location of PDs and magnitude estimation are important tools for both diagnosis and prognosis of the health of large transformers. In reality there is limited access and knowledge of a winding and consequently any practical method requires the use of estimation techniques. The approach taken in this thesis is by considering lumped circuit parameter models. Firstly, a lumped capacitive parameter model was considered and secondly a transmission line lumped parameter approach developed. A technique of split winding analysis is introduced for both types of model. The derivation of the capacitive network considers the source location of a PD by defining the PD signal propagation in two directions. At the source, the currents are equal in magnitude and are attenuated as they flow in each direction. This provides information for a fixed distribution model equation. Under transmission line lumped parameter models, split winding analysis explains the development of accumulated harmonic waveforms of the PD propagation signal towards the neutral and bushing tap-point. At the source, a D’Alembert solution is employed to estimate the oscillation level and found to be in very good agreement with measured data using rectangular wave signal injection. PD signal behaviour is then considered using a time varying boundary conditions model with a principle of superposition equation of source signal. Duhamel’s principle is employed to find a solution for any waveform applied to some point on the transformer winding. Under the influence of losses and distortion, an accumulated harmonic amplitude analysis from the Duhamel’s principle estimates the PD propagation level. For different injection points along the transformer winding, the measured PD level at the neutral and bushing tap point caused by the accumulated harmonic amplitude reveals different patterns. As the PD injection point is altered from the bushing tap point to the neutral, the measured signals significantly change. This in turn contains information of the level of discharge signal at the source. From this analysis a technique based on minimum mean error (MME) calculation using the measurements at the bushing tap and neutral points can be used to identify the source location of PDs based on the analysis of accumulated harmonic amplitudes. With a known location, the information can then be used to estimate PD levels. As the actual charge transferred at the location of a partial discharge cannot be measured directly, by using the D’Alembert solution, the PD source level is found to have approximately twice the apparent magnitude. By using the predominantly capacitive model derived based on split current propagation, PD estimation at higher frequencies is also possible. As a result, an estimation of PD level can be estimated for measurement signals having bandwidth of up to 150MHz.

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Jamieson, John W. "Signal processing techniques for on-line partial discharge monitoring of high voltage electrical machines". Thesis, Robert Gordon University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260064.

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Javadi, Mohammadjavad. "Developing Verification Models for Corona Discharge Suppression in High Voltage Capacitor Banks". Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-96017.

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Due to the universal considerable population and economic growth rate, demands for energy have risen significantly over the past decade. This means that the integration of renewable energies in the power grid has escalated as well as requests for reactive power compensation, voltage stability, and mitigation of harmonic filters. Capacitor banks are widely used in the modern electrical transmission system in order to improve power quality and efficiency. In other words, this device aims to be involved in harmonic disturbance elimination, improve the power factor (PF), provide voltage control and stability which leads into more sustainable energy systems. Utilizing high voltage components, such as shunt capacitors in the power grid can introduce new challenges. One of these challenges is known as corona discharge. The aim of the presented master thesis is to study and develop corona discharge suppression models on high voltage capacitor banks which is implemented in collaboration with ABB power grids, Sweden. The main concerns are, effective factors on corona emergence, corona inception voltage levels, and corona suppression methods. Also, this study evaluates the verification of existing suppression. Two various approaches were applied and compared. The aim of the first approach is to evaluate corona discharge by electric field calculations on three various capacitor banks with different voltage levels. The simulation was implemented based on Maxwell’s equations and finite element method (FEM) by utilizing COMSOL Multiphysics software. The second approach is based on streamer inception and propagation. The calculation on this method is fulfilled with the help of MATLAB software. The results of both approaches were found reasonably compatible. It is discovered that corona discharge can appear in different voltage levels on capacitor banks based on various factors, such as the geometry of the bank. Consequently, the suppression method may vary case by case and different proposals were suggested in order to optimize the corona suppression rings.
På grund av den allmänna betydande befolknings- och ekonomiska tillväxttakten har kraven på energi ökat markant under det senaste decenniet. Detta innebär att integrationen av förnybara energier i elnätet har eskalerat samt begäran om reaktiv effektkompensering, spänningsstabilitet och mildring av harmoniska filter. kondensatorbatterier används ofta i det moderna elektriska transmissionssystemet för att förbättra strömkvaliteten och effektiviteten. Med andra ord syftar denna enhet till att vara involverad i eliminering av harmonisk störning, förbättra effektfaktorn (PF), tillhandahålla spänningskontroll och stabilitet som leder till mer hållbara energisystem. Att använda högspänningskomponenter, som shuntkondensatorer i elnätet, kan skapa nya utmaningar. En av dessa utmaningar kallas korona-urladdning. Syftet med den presenterade masteruppsatsen är att studera och utveckla korona-urladdningsmodeller på högspännings-kondensatorbatterier som implementeras i samarbete med ABB Power Grids, Sverige. De viktigaste problemen är effektiva faktorer för korona uppkomst, spänningsnivåer korona och metoder för att underlätta korona. Dessutom utvärderar denna studie verifieringen av befintliga undertryckningsmetoder. Två olika tillvägagångssätt tillämpades och jämfördes. Syftet med det första tillvägagångssättet är att utvärdera korona-urladdning genom elektriska fältberäkningar på tre olika kondensatorbatterier med olika spänningsnivåer. Simuleringen implementerades baserat på Maxwells ekvationer och finita elementmetoden (FEM) genom att använda COMSOL Multiphysics programvara. Det andra tillvägagångssättet är baserat på strömningslinjernas början och utbredning. Beräkningen av denna metod genomförs med hjälp av MATLAB-programvaran. Resultaten från båda metoderna tycktes vara rimligt kompatibla. Det upptäcks att korona-urladdning kan förekomma i olika spänningsnivåer på kondensatorbatterier baserat på olika faktorer, till exempel batteriets geometri. Följaktligen kan undertryckningsmetoden variera från fall till fall och olika förslag föreslogs för att optimera koronaundertryckningsringarna.

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Blackmore, Paul David. "Degradation of polymeric outdoor high voltage insulation : surface discharge phenomena and condition assessment techniques". Thesis, Queensland University of Technology, 1997.

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Zhao, Zhe, Zuopeng Liu, Jiaheng Shan, Liang Ding, Tianlun Li, Tao Jiang, Tao Li e Junyu Wang. "Expansion and Identification of High Voltage Cable Joint Defect Partial Discharge Data". In Lecture Notes in Electrical Engineering, 353–60. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-1351-6_38.

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Xu, Yuanzhe, e Hongzhen Chen. "Study on UV Detection of High-Voltage Discharge Based on the Optical Fiber Sensor". In Lecture Notes in Electrical Engineering, 15–22. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-21747-0_3.

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Wu, Tianbao, Huan Bai, Jiayi Wang, Jianyang Huang, Yue Yu e Weiwang Wang. "Partial Discharge Pattern Recognition of High Voltage GIS Defects by Using GWO-SVM Method". In Lecture Notes in Electrical Engineering, 657–64. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-1072-0_67.

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Adda, P., N. Boussetta, O. Lesaint e E. Vorobiev. "High-Voltage Electrical Discharge Assisted Extraction of Phenolic Compounds from Grape Seeds". In Handbook of Electroporation, 1–26. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-26779-1_154-1.

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Adda, Pierre, Nadia Boussetta, O. Lesaint e Eugène Vorobiev. "High-Voltage Electrical Discharge-Assisted Extraction of Phenolic Compounds from Grape Seeds". In Handbook of Electroporation, 2799–824. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-32886-7_154.

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Xu, Yongsheng, Bing Luo, Jiaju Lv, Qihang Jiang e Weiwang Wang. "Study on Partial Discharge Characteristics of Epoxy Resin Under Bipolar High-Frequency Square Wave Voltage". In Lecture Notes in Electrical Engineering, 649–56. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-1072-0_66.

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Atti di convegni sul tema "High voltage electrical discharge (HVED)"

Maloney, T. J., K. Parat, N. K. Clark e A. Darwish. "Protection Of High Voltage Power And Programming Pins". In Proceedings Electrical Overstress/Electrostatic Discharge Symposium. IEEE, 1997. http://dx.doi.org/10.1109/eosesd.1997.634249.

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Mohamed, R., e P. L. Lewin. "Partial discharge location in high voltage transformers". In 2009 IEEE Electrical Insulation Conference (EIC) (Formerly EIC/EME). IEEE, 2009. http://dx.doi.org/10.1109/eic.2009.5166345.

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Kassirov, G. M., F. G. Sekisov e V. N. Chekrygin. "Discharge in commercial vacuum at high voltage". In XVI International Symposium on Discharges and Electrical Insulation in Vacuum, a cura di Gennady A. Mesyats. SPIE, 1994. http://dx.doi.org/10.1117/12.174647.

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Khelil, D., S. Bouazabia, MM Munzunzi e Z. Omari. "Electrical discharge modeling with vertical rod protection: Randomness discharge effect". In 2014 International Conference on High Voltage Engineering and Application (ICHVE). IEEE, 2014. http://dx.doi.org/10.1109/ichve.2014.7035391.

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Murray, A. C. "Slot discharge signal patterns in high voltage machines". In Seventh International Conference on Electrical Machines and Drives. IEE, 1995. http://dx.doi.org/10.1049/cp:19950855.

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Keppens, Bart, Markus P. J. Mergens, Cong Son Trinh, Christian C. Russ, Benjamin Van Camp e Koen G. Verhaege. "ESD protection solutions for high voltage technologies". In 2004 Electrical Overstress/Electrostatic Discharge Symposium (EOS/ESD). IEEE, 2004. http://dx.doi.org/10.1109/eosesd.2004.5272593.

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Wootton, R. E. "An expert system for high voltage discharge tests". In Conference on Electrical Insulation & Dielectric Phenomena — Annual Report 1987. IEEE, 1987. http://dx.doi.org/10.1109/ceidp.1987.7736535.

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Lee, Jian-Hsing, Natarajan Mahadeva Iyer, Ruchil Jain e Manjunatha Prabhu. "Predictive high voltage ESD device design methodology". In 2016 38th Electrical Overstress/Electrostatic Discharge Symposium (EOS/ESD). IEEE, 2016. http://dx.doi.org/10.1109/eosesd.2016.7592525.

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Lewin, P. L., I. O. Golosnoy e R. Mohamed. "Locating partial discharge sources in high voltage transformer windings". In 2011 Electrical Insulation Conference (EIC) (Formerly EIC/EME). IEEE, 2011. http://dx.doi.org/10.1109/eic.2011.5996145.

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Nishigaki, Yasutaka, Takakazu Matsuzoe, Sho Takenouchi, Masahiro Kozako, Masayuki Hikita, Takahiro Nakamura, Jintong Sun et al. "High Temperature Partial Discharge Inception Voltage under Repetitive Impulse Voltage Applied to Motorette Samples". In 2020 IEEE Electrical Insulation Conference (EIC). IEEE, 2020. http://dx.doi.org/10.1109/eic47619.2020.9158767.

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Rapporti di organizzazioni sul tema "High voltage electrical discharge (HVED)"

Yoshida, Koji, e Hideo Shoji. The Fuel Injection System Using the High-Voltage Electrical Discharge. Warrendale, PA: SAE International, ottobre 2005. http://dx.doi.org/10.4271/2005-32-0075.

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