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Grav, Torstein. "Mechanisms Governing the occurrence of Partial Discharges in Insulation Liquids". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22385.
Pełny tekst źródłaSadeghzadeh-Araghi, Mohsen. "The initiation and development of negative discharges in dielectric liquids : a computer aided investigation". Thesis, University of Salford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258230.
Pełny tekst źródłaNominé, Anna V. "Synthesis of Bi₂O₂CO₃ nanosheets by electrical discharges in liquids for photocatalytic and nanoelectronic applications". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0357.
Pełny tekst źródłaThis work provides information on the synthesis of ultrathin nanosheets composed of Bi₂O₂CO₃, hereafter referred to as BOC. The synthesis is achieved through the rapid and straightforward technique known as Electrical Discharges in Dielectric Liquids (EDDL). To ensure the reproducibility of the synthesis, a pre-treatment method involving the etching of bismuth electrodes with Nital was employed. The chosen process entails initiating electrical discharges between these electrodes while submerged in either liquid nitrogen or water. Remarkably, both liquids produced identical nanostructures, a similarity validated by optical emission spectroscopy, which confirmed the metallic nature of the discharge in both environments. Following this stage, the nanosheets undergo rapid oxidation and carbonation upon exposure to air. The proposed growth mechanism is closely linked to the ledge mechanism, considering the presence of clearly visible kinks and jogs along the edges of the nanosheets. These two-dimensional nanostructures first emerge on the cathode's surface and then grow vertically. This anisotropic growth is made possible by ion assistance in regions that exhibit comb-like patterns formed during the chemical etching step, which is a necessary precondition for high reproducibility of the discharge process. Detailed crystallographic characterization of BOC nanosheets was achieved through a range of techniques, including Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), High-Resolution TEM Transmission Electron Microscopy (HRTEM), Energy-Dispersive X-ray Spectroscopy (EDX), Selected Area Electron Diffraction (SAED), Convergent Beam Electron Diffraction (CBED), Energy Filtered Transmission Electron Microscopy (EFTEM), and Electron Energy-Loss Spectroscopy (EELS). The investigation reveals that the crystallographic structure of BOC conforms to the space group I4/mmm, with lattice parameters a=3.91 Å and c=13.77 Å, a determination that was confirmed by X-ray Diffraction (XRD). The study also clarifies the potential origin of satellite spots that are consistently observed in SAED patterns along the [001] zone axis. In this research, these spots were primarily attributed to two phenomena: multiple diffraction and local disorder-to-order transformations occurring within the BOC crystal structure. This transformation entails a transition from a body-centered tetragonal structure to a primitive Bravais lattice. To gauge their practical usefulness, we assessed the photocatalytic performance of BOC nanosheets synthesized using the EDDL method and found it to be consistent with BOC obtained through alternative methods. Furthermore, we explored the electronic performance of BOC with the goal of uncovering their potential in nanodevice applications
Okubo, H., H. Kojima, F. Endo, K. Sahara, R. Yamaguchi i N. Hayakawa. "Partial Discharge Activity in Electrical Insulation for High Temperature Superconducting (HTS) Cables". IEEE, 2008. http://hdl.handle.net/2237/12061.
Pełny tekst źródłaHernandez, Avila José Luis. "Etude des decharges couronne dans l'argon et l'azote, du gaz au liquide". Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10173.
Pełny tekst źródłaPajurková, Jana. "Diafragmový výboj v roztocích organických barviv". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216665.
Pełny tekst źródłaZhou, Rusen. "Low-temperature discharge plasmas in liquids assisted biomass conversion". Thesis, Queensland University of Technology, 2021.
Znajdź pełny tekst źródłaQureshi, Mohammad Iqbal. "Relationship between current pulses and discharges in liquid dielectrics". Thesis, University of Salford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315303.
Pełny tekst źródłaPrior, Alison D. "Towards achieving Zero Liquid Discharge in process industry". Thesis, Prior, Alison D. (2008) Towards achieving Zero Liquid Discharge in process industry. Honours thesis, Murdoch University, 2008. https://researchrepository.murdoch.edu.au/id/eprint/38933/.
Pełny tekst źródłaDavidová, Jaroslava. "Diafragmový výboj v roztocích organických barviv z hlediska elektrolytického rozkladu". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216664.
Pełny tekst źródłaFaderani, Shokrollah dabbaghi Varnos. "Discharge and transport of nearly-buoyant coarse granular solids in liquids". Thesis, University of Surrey, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336751.
Pełny tekst źródłaLiu, Zhao. "Partial discharge and streamer characteristics of transformer liquids under AC stress". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/partial-discharge-and-streamer-characteristics-of-transformer-liquids-under-ac-stress(82628a33-9bc3-467f-899a-7240307d7601).html.
Pełny tekst źródłaSmith, Gordon V. "A study of electrode erosion by discharges in a dielectric liquid". Thesis, University of Surrey, 1991. http://epubs.surrey.ac.uk/843078/.
Pełny tekst źródłaLamptey, Benjamin Odarkwei Mills. "The discharge of solid-liquid mixtures from storage vessels". Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335132.
Pełny tekst źródłaHarper, Grant. "Biomass-powered zero liquid discharge desalination of brackish water". Thesis, Harper, Grant (2018) Biomass-powered zero liquid discharge desalination of brackish water. Honours thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/44867/.
Pełny tekst źródłaWang, Xin. "Partial discharge behaviours and breakdown mechanisms of ester transformer liquids under AC stress". Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/partial-discharge-behaviours-and-breakdown-mechanisms-of-ester-transformer-liquids-under-ac-stress(43a16189-379b-4645-870c-ccc5cb03bf06).html.
Pełny tekst źródłaYi, Xiao. "Characteristics of creepage discharges along ester-pressboard interfaces under AC stress". Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/characteristics-of-creepage-discharges-along-esterpressboard-interfaces-under-ac-stress(73749539-3231-467e-b5ee-1c7aa6eaabe8).html.
Pełny tekst źródłaInvernizzi, Laurent. "Développement, caractérisation et optimisation d'une source plasma pour le traitement de liquides". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30231.
Pełny tekst źródłaIn recent decades, a growing interest in the characterization and optimization of atmospheric pressure plasma jets has emerged due to the variety of possible applications. One of them concerns the decontamination of liquids containing pollutants. Indeed, plasma jets are capable of creating oxidizing agents such as reactive oxygen and nitrogen species (RONS), electric fields, UV/VUV radiation and charged species. In particular, the variety and number of RONS that are created and deposited in the liquid phase are two key parameters. Understanding and optimizing them is fundamental to the development of an effective plasma source for liquid decontamination. The creation of RONS is possible by a cascade of energy transfers between the species in the plasma, the surrounding air and the liquid target placed in contact with the plasma jet. Therefore, it is necessary to study the species providing these RONS, namely the metastable helium atoms He(23S). These species have the particularity of storing a relatively high energy (19.8 eV), and can release it several tens of nanoseconds after, in the case of plasma in He + 0.2% O2 mixture. The collision between these metastables and air species causes the creation of reactive species in the gas and liquid phase. These reactive species can then reduce or destroy the pollutant present in the water. In this work, the study is separated in three parts: the plasma, the liquid, and the biocidal efficiency of the plasma jet. The study of the source geometry influence, the flow rate or the gas mixture on the quantity of metastable helium atoms in the plasma jet is performed by laser absorption spectroscopy. The use of Abel inversion allows the density and lifetime of these species to be determined locally in the plasma jet during its interaction with a liquid target. Optical emission spectroscopy is used to map all excited species between 200 and 1000 nm present in the plasma jet. These excited species in the plasma are also studied using an intensified camera to monitor the spatial and temporal evolution of the plasma jet during its propagation in the air. The asymmetric source, whose mass electrode has a larger surface than a conventional source (symmetric source), produces more metastable helium atoms and excited species. The quantities of the main RONS (hydrogen peroxides, nitrites and nitrates) were measured in the liquid. The complex molecule targeted in this study to model water pollutant is methylene blue.[...]
Lokajová, Aneta. "Analýza produktů elektrického výboje ve směsích vody a etanolu". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401875.
Pełny tekst źródłaHayakawa, N., M. Nagino, H. Kojima, M. Goto, T. Takahashi, K. Yasuda i H. Okubo. "Dielectric characteristics of HTS cables based on partial discharge measurement". IEEE, 2005. http://hdl.handle.net/2237/6772.
Pełny tekst źródłaKoch, Benedikt. "Greening or greenwashing dirty laundry? Tracing sustainability in the Tirupur textile cluster". Thesis, Linköpings universitet, Tema Miljöförändring, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129924.
Pełny tekst źródłaSully, Vicky Ann. "Characterisation of the discharge flowrate and dispersion of non-flashing liquid releases through failed pipe flanges". Thesis, London South Bank University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369883.
Pełny tekst źródłaMarinov, Ilya. "Plasmas in liquids and at the interfaces". Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00998381.
Pełny tekst źródłaDahlgren, Maja. "Breaking the silos: Bridging the resource nexus in the textile industry when adapting to Zero Liquid Discharge". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-295909.
Pełny tekst źródłaLewis, Christopher James. "Development of a Methodology for Numerical Simulation of a D C ARC Discharge in a Liquid Dielectric". BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/2394.
Pełny tekst źródłaChvátalová, Barbora. "Kapalné výpusti 14C v českých jaderných elektrárnách a odhad jejich radiologických dopadů". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-295644.
Pełny tekst źródłaBagiante, Salvatore. "Carbon Nanotubes: Synthesis, Characterization and Integration". Thesis, Universita' degli Studi di Catania, 2011. http://hdl.handle.net/10761/107.
Pełny tekst źródłaNěmcová, Lucie. "Interakce plazmatu s kapalnou fází". Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2013. http://www.nusl.cz/ntk/nusl-233370.
Pełny tekst źródłaOkubo, H., M. Hazeyama, N. Hayakawa, S. Honjo i T. Masuda. "V-t characteristics of partial discharge inception in liquid nitrogen/ PPLP/sup /spl reg// composite insulation system for HTS cable". IEEE, 2002. http://hdl.handle.net/2237/6762.
Pełny tekst źródłaMuslim, Joko. "Study of dielectric liquids as alternative encapsulant for high temperature electronics power modules applications". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT109.
Pełny tekst źródłaTodays, power electronics cover wide range of applications in our daily life, starting from household appliances, communications, transportation systems up to harsh and extreme environment as in oil and gas exploration and the deep space missions. The main deliveries of power electronics are energy efficiency, compact size, reliability, long durability. Improving power electronics will surely mean to deal with materials, the packaging system, switching technologies, heat dissipation, dielectric properties, thermal stability etc. It was since the first arc-mercury rectifying in traction system, and then reshaped by the discovery of classical semiconductor (Si based) and ultimately the wide bandgap semiconductor materials, such as SiC, GaN and carbon based (diamond). They have superior thermal and dielectric properties compared to previous classical semiconductor technologies (Ge, Si and GaAs), and allow devices to operate at higher voltage, temperature and switching frequency in power modules. Unfortunately, these developments are not equally followed by other parts within, such as encapsulant.Despite their key roles to provide mechanical and electrical protection inside a power module, silicone gel as major encapsulant is limited to 200°C, which is far below devices (e.g. SiC at 500°C). Encapsulant came from polymerization and curing process of silicone liquids mixture and transforms into gel. They worked very well when assembly with classical SC devices, but not with WBG SC. Thus, it is necessary to solve this thermal related issue by improving silicone gel or start looking for other type of encapsulant with better thermal performance such as dielectric liquid or gas.Dielectric liquids have been used as insulating medium for high voltage (HV) applications for decades. Their excellent self-healing and arc quenching properties were used in the HV circuit breaker applications even though nowadays replaced by gas. Their low viscosity allow the fluid flow to exchange heat from internal source yielding effective cooling system as in power transformers. Other industries use dielectric liquids as heat transfer liquid at much higher temperature range compare to those in HV applications. Of course as heat transfer liquids, their dielectric properties are out of considerations. Nevertheless, having this wide range of applications spectrum, dielectric liquids seem rather promising and potential as alternative encapsulant. Some questions then aroused such as how are their electrical properties at high temperature (HT) approx. 400°C, are their dielectric properties stable at HT and can they contribute to cooling of devices inside power module.This work presents the initial study of dielectric liquids for HT power electronics module applications. We demonstrated the electrical characterization of several dielectric liquids under influence of temperature such as dielectric spectroscopy and ion mobility measurement, partial discharge, streamers and breakdown. Interesting physical phenomena such as liquid motions due to EHD and natural thermal convection were observed during experiments. Comparison among liquids are showed to indicate the most convenient. In term of application, conditions were adapted and simplified to replicate as those in power module when we performed characterizations to actual ceramic substrates under quasi-uniform to highly divergent electric field with AC, DC and impulse voltage. Many fundamental behaviours of liquids have been confirmed and evidenced at HT range. Governing parameters for electrical properties such as breakdown, charge injection etc. were affirmed.While not all aspects of encapsulant requirement in term of HT are covered, this work has established essential basis for electrical properties of dielectric liquids. Further works are required to fully assess their compatibility as alternative encapsulant, such as thermal ageing process, cooling contribution, complete modelling, etc
Kabbara, Hiba. "Élaboration de nanoparticules par décharges spark nanosecondes dans des liquides diélectriques : compréhension des mécanismes élémentaires et synthèse de composites". Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0038/document.
Pełny tekst źródłaDischarges in liquids offer a simple way to synthesize nanoparticles at high rate and low cost. When spark discharges are ignited in a dielectric liquid, a strong heating of the electrode material occurs, producing a metallic vapor from which nanoparticles grow by condensation. Even if most of the energy is dissipated in the formation of the discharge, the erosion of the metal electrodes allows the efficient production of NPs. The nature of the NPs formed is largely dependent on the dielectric liquid in which the discharge is performed. It is thus possible to control the nanoparticles produced by choosing the electrodes and the liquid in an appropriate manner. We seek in this work to understand the mechanisms that take place during the discharge by studying different cases of elaboration of NPs either alloys or composites. The synthesized NPs will have applications in various fields depending on the material(s) chosen. Using a nanosecond pulse generator, the discharges were created by applying a high voltage pulse (10 kV-200ns-10 Hz) between two electrodes immersed in liquid nitrogen. Three main systems have been studied: Si-Sn, Cu-Zn and Cu-Ag. The tests were performed with pure electrodes or alloys containing the 2 elements in varying proportions to improve our understanding of how nanoparticles are formed. High resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), electron energy loss spectroscopy (EELS) and micro-diffraction analyzes were carried out to characterize the synthesized NPs (morphology, crystallinity, chemical composition, etc.). Finally, time-resolved optical emission spectroscopy measurements were performed to obtain information on the temporal evolution of the lines emitted during the discharge and thus on the conditions that prevail in the plasma
Klímová, Edita. "Elektrické výboje ve vodných a organických roztocích". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2013. http://www.nusl.cz/ntk/nusl-216930.
Pełny tekst źródłaAdámková, Barbora. "Diagnostika plazmatu generovaného ve směsích vody a alkoholů". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-414082.
Pełny tekst źródłaKogelheide, Friederike [Verfasser], Peter [Gutachter] Awakowicz i Katharina [Gutachter] Stapelmann. "Characterisation of a dielectric barrier discharge and its impact on liquids and biological systems / Friederike Kogelheide ; Gutachter: Peter Awakowicz, Katharina Stapelmann ; Fakultät für Elektrotechnik und Informationstechnik". Bochum : Ruhr-Universität Bochum, 2021. http://d-nb.info/1226428630/34.
Pełny tekst źródłaProcházková, Michaela. "Studium působení plazmatu na roztoky chininu". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-414084.
Pełny tekst źródłaIost, Caroline. "Produção de sedimentos e qualidade da água de uma microbacia hidrográfica rural". Universidade Estadual do Oeste do Parana, 2008. http://tede.unioeste.br:8080/tede/handle/tede/285.
Pełny tekst źródłaCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
The objective of this work was to evaluate the influence of land use in the production of sediment and water quality of the micro basin of river Mandarina micro basin, located in the city of Cascavel-PR. The liquid discharge, the suspended sediment and the physic-chemical parameters dissolved oxygen (DO), electrical conductivity, pH, temperature of the water, turbidity, color, nitrate, nitrite, total nitrogen, total phosphorus was monitoring between the months January and August 2007 at the river's main. It was determined the curve-key of the liquid discharge and discharge of suspended solid, which showed good correlation (R2 equal to 0.98 and 0.93, respectively). The results indicated a low production of sediment, average of 0,27 t dia-1 and good water quality, because the parameters have not gone beyond the limits praised by Resolution 345/05 of CONAMA for rivers, Class 2, with the exception of dissolved oxygen in some collections was below 5 mg L-1, color and total phosphorus which also exceeded the limits stipulated. Agriculture is the predominant activity in the micro basin (88%) and water courses have about 79% of the area of riparian forest required by law. It is believed that the soil management in the area of agriculture with practices such as tillage and system of terraces, as well as the presence of riparian forest in rivers, influenced for the good quality water and low production sediment on the water.
O objetivo deste trabalho foi verificar a influência do uso do solo na produção de sedimento e na qualidade da água da microbacia hidrográfica da sanga Mandarina, localizada no município de Cascavel-PR. A vazão, o sedimento em suspensão e os parâmetros físico-químicos da água, oxigênio dissolvido (OD), condutividade elétrica, pH, temperatura da água, turbidez, cor, nitrato, nitrito, nitrogênio total e fósforo total foram monitorados entre os meses de janeiro e agosto de 2007, no principal rio da microbacia. Determinou-se a curva-chave da vazão e da descarga sólida em suspensão, as quais apresentaram boa correlação (R2 igual a 0,98 e 0,93, respectivamente). Os resultados indicaram uma baixa produção, média de 0,27 t dia-1 de sedimento e uma boa qualidade da água, pois os parâmetros não ultrapassaram os limites regidos pela Resolução 345/05 do CONAMA para rios de Classe 2, com exceção do oxigênio dissolvido que em algumas coletas esteve abaixo de 5 mg L-1, cor e fósforo total que também ultrapassaram os limites estipulados. A agricultura é a atividade predominante na microbacia (88%) e os cursos d água apresentam cerca de 79% da área de mata ciliar exigida por lei. Acredita-se que o manejo do solo na área agricultável com práticas como o plantio direto e sistema de terraços, assim como a presença de mata ciliar nos rios influenciaram para o boa qualidade da água e baixa produção de sedimento no curso d água.
Nguyen, Thi Hai Van. "Spectroscopie d'émission d'un plasma crée par des décharge couronne dans l'hélium". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT002/document.
Pełny tekst źródłaFluorescence spectroscopy is a powerful tool to obtain information on microscopicprocesses in non-equilibrium discharge plasma (corona) in dense media such as high pressuresupercritical gas and even liquids. Spectroscopic observations of the light emitted from anionization zone near a tip electrode can be used to determine structural information of thelocal environment of the emitting atoms or molecules. The spectral features observable aresensitive to the immediate surroundings of the emitting species, which makes emissionspectroscopy very useful for study of the cold nonequilibrium plasma varying the pressureand the temperature.In this work, we have studied the current-voltage characteristics and spectralcomposition of helium cryoplasma initiated with a corona discharge in gaseous and liquidhelium. A cryoplasma has been realized in laboratory conditions using corona discharge ingaseous and liquid Helium at cryogenic temperatures of the matter. Experiments were carriedout at a number of fixed temperatures from 300 K down to 4.2 K within the pressure range0.1÷10 MPa. The conditions covered a wide region of thermodynamic states of the mattersuch as from a gas with density of ~1019 cm-3 up to liquid Helium with density of 2*1022cm-3
Maier, Marcus R. "Onsets of liquid and gas entrainment during discharge from a stratified air-water region through two horizontal side branches with centerlines falling in an inclined plane". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0003/MQ32176.pdf.
Pełny tekst źródłaHaidara, Modibo. "Impulsions de Trichel dans le cyclohexane liquide et les gaz comprimés". Grenoble 1, 1988. http://www.theses.fr/1988GRE10160.
Pełny tekst źródłaSumonsiri, Nutsuda. "Effect of Powder and Target Properties on Food Powder Coating and Comparison of Solid-liquid Separation (SLS) and Vacuum Concentration of Tomato Juice". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1336625577.
Pełny tekst źródłaScheiber, Julia [Verfasser], i H. G. [Akademischer Betreuer] Stosch. "Formation of Precipitates in a Desalination Plant with Zero Liquid Discharge : Identification of the main Processes by Mineralogical-Geochemical Methods and Modelling / Julia Scheiber. Betreuer: H.-G. Stosch". Karlsruhe : KIT-Bibliothek, 2012. http://d-nb.info/1020663537/34.
Pełny tekst źródłaTmenova, Tetiana. "Étude expérimentale de la décharge électrique pulsée dans l'eau". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30248.
Pełny tekst źródłaAlthough electric spark dispersion processes have been known for a while, the plasma created during this process is not well-studied and understood. The complexity of the phenomena occurring during the underwater electric discharges brings additional obstacles to experimental characterization of such plasmas imposed by as small sizes of plasma and their often-short duration, difficult environment of the discharge, its stochastic nature and poor reproducibility. The main objective of this thesis was set on the investigation of the plasma occurring during the synthesis of metal colloids by an electrospark dispersion generator. The first success of this work was simply to show the applicability of optical emission spectroscopy diagnostics to such discharges. The efforts made for the development of the effective experimental approach in order to meet this research objective have been well rewarded. The results obtained in this work allow to draw interesting conclusions about the physical properties of the underwater pulsed electric discharge plasma of the considered configuration. Discharge ignites from the short circuit and molten bridge mechanism. Ignition of the arc is characterized by formation of bubble resulting from a pressure shockwave. High-speed imaging allowed to distinguish two phases in the discharge lifetime: plasma in water, and plasma in bubble formed afterwards. From the vapor condensation point of view, these two phases presumably lead to different quenching conditions, and, consequently, to the different synthesis conditions. In the case of discharge generated between molybdenum electrodes, there is a slowly-decaying light emission after the end of the discharge which can be attributed to the ejection of eroded metallic particles. The energy dissipation on the electrodes was found to be different for copper and molybdenum: due to the lower thermal conductivity of molybdenum, smaller portion of energy transferred to the electrodes results in higher energy input into the arc column. Spectroscopic measurements allowed to establish that plasma density (~ 10 17 cm-3) and moderate temperature (0.6 - 0.95 eV) correspond to a pressure greater than 1 bar. Moreover, plasma presents several non-ideal effects, such as broadening and the asymmetrical shape of the Ha line and absence of Hß line. In general, plasma properties were found to be relatively insensitive to most of the discharge parameters, such as the discharge current or the type of liquid with the main differences being associated to the used electrodes material
Holíková, Lenka. "Diagnostika plazmatu výboje ve vodných roztocích a jeho aplikace". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-216715.
Pełny tekst źródłaMassala, Gaston. "Propagation et propriétés électriques des streamers positifs à grande distance dans l'huile minérale sous très haute tension impulsionnelle". Grenoble INPG, 1997. http://www.theses.fr/1997INPG0112.
Pełny tekst źródłaThe aim of this work is to study the propagation of the "streamers" and their electrical properties in mineral oil at long distances under pulsed voltage (up to 480 kV) under various voltage conditions (from the minimum propagation voltage to the high overvoltages), inter-electrode distance (2. 5 to 35 cm), electrode geometry (plane-to-plane, semi-uniform, planar sphere) of solid insulators. This work makes a contribution on the characterization of the breakdown phenomena and the mechanisms involved in the positive streamers. For voltages below the breakdown voltage, stopping, transition to breakdown and conductivity of the streamers are described. In particular, it has been shown that the streamer is conductive only during a total re-ignition of its main branch. In the presence of overvoltages, the existence of an acceleration voltage correlated with the appearance of the fast streamers is highlighted. Three different propagation modes are identified and characterized: 2nd mode (2 to 4 km / s), 3rd mode (10 to 20 km / s) and 4th mode (> 100 km / s). A correlation between the shape, speed and load of the streamers was highlighted and the voltage drop in the streamer was determined. Calculations of the charge and field on the plane electrode carried out by the Load Simulation Method (CSM), considering different macroscopic models in the presence of a voltage drop, have led to the conclusion that the streamers are comparable to objects conductors of simple shape (cylinder or sphere). A qualitative correlation between the macroscopic field at the end of the streamers calculated by CSM, and the speed was obtained. E there exists a critical field = 400 kV / cm, beyond which the streamers are always fast (> 10 km / s). This work proposes two complementary mechanisms allowing to explain the constancy of the speed of the positive streamers in the mineral oil: the effect of the voltage drop and / or the electrostatic effect due to the branching of the streamers. It has been shown that the overall shape of the streamers determines the field at their end and hence the propagation modes. This has been verified by studying the influence of electrode geometry (shielding effect), insulating solids (positional effect) and the nature of the liquid (additive effect)
Clermont, Paul Daniel Stanley. "Characterization and prediction of flow electrification phenomena in fuel tanks of aeronautical structures". Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2258/document.
Pełny tekst źródłaWith the new generation of composite aircrafts an attention is carried out on fuel systems with respect to prevention of electrostatic discharges (ESD) during the filling phases of the tanks. Most of the work realized in aeronautics (during the 60's) was conducted on metallic fuel tanks. However, the introduction of composite materials has raised new questions, since those materials can have a different behavior than metallic ones with respect to flow electrification, which fully justify new analyses. In order to properly define the tank structures and their protection against ESD hazards, it is crucial to understand how a complex stack of materials (conductive or not, multilayered or homogeneous, painted or not) constituting a fuel tank behaves with respect to the mechanisms of charge creation by flow electrification when these materials are in contact with aviation fuel. The structure of these materials and their electrical properties control the electric potential reached in the tank through a balance between the production, accumulation and leakage of the electrical charge. This potential may exceed the flash point of the fuel vapors/air mixture and induce ignition. Various protective measures can be adopted to control this phenomenon such as using antistatic additives in the fuels, lowering the rates ofthe fuel injection inside the tank, using only bonded metallic tanks or tanks made of non-metallic materials which do not favor charge accumulation or local charge trapping. It is majorly in response to the latter solution that this work is oriented in order to guide optimum choices of materials and a better definition of the tank structures
Bouras, Meriem. "Etude comparative et optimisation de prétraitements des écorces de bois pour l'extraction des composés phénoliques". Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2245.
Pełny tekst źródłaThis research work focuses on the intensification of polyphenols extraction from Quercus robur and Norway spruce barks using innovative technologies : pulsed electric field (PEF), ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE). These pre-treatments enhance the release of intracellular compounds by damaging the membrane and/or cell wall. The effect of each of these technologies (PEF, UAE and MAE) on polyphenols extraction has been highlighted in a quantitative and qualitative optimization analysis by evaluating the polyphenols concentration, antioxidant activity and by the chemical characterization of the extracted compounds.A comparative study of pre-treatments (PEF, UAE and MAE) coupled with an extraction step in an alkaline hydro-alcoholic medium allowed us to better understand the involved phenomena. The induced process efficiency is independent of the tree family to which the bark belongs (coniferous and hardwood). For bark valorization, the application of PEF treatment (20 kV/cm, 200 pulses, 3.2 kJ/g bark) followed by a diffusion step seems to be an alternative to ultrasound and microwave assisted extractions and to the extraction from grinded barks. In fact, the electrical and mechanical effect of PEF treatment allow to obtain an extract rich in polyphenols (10.5 g GAE/100g DM and an efficiency of 83 % for Norway spruce and 5 g GAE /100g DM and an efficiency of 82 % for Quercus robur bark)
Vu, Thi Anh Tho. "Etude de l'origine des décharges partielles sur des substrats céramiques enrobés". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00612433.
Pełny tekst źródłaNejezchleb, Martin. "Analýza degradačních produktů organického barviva po rozkladu v diafragmovém výboji". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-216463.
Pełny tekst źródłaGirard, Fanny. "Analyse physico-chimique de milieux liquides d’intérêt biologique exposés à des plasmas froids produits à pression atmosphérique et température ambiante". Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3025/document.
Pełny tekst źródłaCold plasmas are partially ionized gases, very rich in a physico-chemical point of view. This property characterizes cold plasmas today generated at atmospheric pressure and ambient temperature and was used since about fifteen years approximately for biomedical applications (haematology, dermatology, cancer research, odontology etc.). The efficiency of these cold plasmas in the field of the medicine was proved by numerous studies. However, the involved biological phenomena are not still well included, and it is essential to know what could be the possible unwanted side effects of these reactive ionized gases. The first level of interaction of plasmas with living matter is the one with the liquid phase, which is present on the tissue surface, in vivo cells or in culture. For a decade, a particular attention was thus worn in the interactions of plasmas with liquids, to bring a level of additional understanding. The understanding of these interactions constituted the axis of this work. Various cold plasmas reactors (generated at atmospheric pressure and ambient temperature) were developed, in order to control the interactions of these plasmas with the ambient air which can be problematic for the aimed applications. The nature of the gas used to initiate the plasma was modified, to know its influence on the chemical reactivity of the gas phase. For that purpose, measurements of optical emissive spectroscopy (OES) were necessary. Besides, new electrochemical sensors and methodological approaches were developed in order to identify and quantify the reactive nitrogen and oxygen (RONS) produced in physiological liquid media, exposed to these ionized gases. The electrochemical analyses were combined UV-visible absorption spectroscopy as well as other methods of chemistry (pH-metry/conductimetry). One of the aimed objectives is to establish a correlation between the reactive species generated in the gas phase and in the liquid phase. Finally, experiments allowed us to analyze the production of RONS in liquids in situ and in real time. OES measurements showed that there are numerous chemical species generated in various plasmas (NO°, HO°, O, N2+ (FNS) etc.). The analyses of the liquid phase revealed the presence of stable oxygen and nitrogen species (H2O2, NO2-, NO3-), directly correlated with the species detected in plasmas. Furthermore, the diverse methodologies of chemical analysis allowed the detection and quantification of RONS such as the peroxynitrite anion ONOO-. The obtained results should allow to arrest in a finer way the effects led by various cold plasmas in physiological liquid media to establish links with the studies led on cultured cells and on skin within the framework of a research program financed by the ANR, National Agency of the Research
Wengler, Julien. "Synthèse organique en micro-réacteur plasma". Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS274.
Pełny tekst źródłaThe present thesis relates the integration of nonthermal plasma inside a biphasic gas-liquid microfluidic chip. It evaluates the ability of plasma activation to become a synthetic tool for a greener organic chemistry operating in mild conditions and without catalyst. Few preceding works on plasma chemistry involved a liquid phase and none of them was able to handle the high reactivity of plasma to achieve both high conversion rate and selective reactions. We developed and fabricated a glass-polymer microfluidic chip comprising a one-metre-long serpentine channel, in which a parallel gas-liquid flow was stabilized thanks to a specific step-like cross-sectional shape. An AC high voltage linked to transparent ITO electrodes produced a homogeneous atmospheric pressure Townsend discharge all along the channel. We assessed the behaviour of the flow through optical observations and characterized the discharge through electrical measurements and real time intensified-CCD monitoring. Liquid cyclohexane was successful treated with pure oxygen plasma inside our chip. The GC analysis of the outflowing liquid revealed a partial oxidation of cyclohexane into a mixture of cyclohexanol, cyclohexanone (both industrially known as "KA oil"), and cyclohexyl hydroperoxide, with a routine performance of 10-20% conversion for 70-80% selectivity. A numerical simulation was performed to identify the main reactive route and a mechanistic study was conducted. Through this controlled activation and functionalization of an alkane by means of plasma discharges, we claim to have successfully overcome some of the principle barriers towards an industrially relevant plasma chemistry