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Droubi, Ashraf El. "Investigation of the efficiency of a novel three electrode configuration for the dielectric barrier discharge." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-03102018-144641/.
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Having gained popularity in the last decade, the dielectric barrier discharge (DBD) has been studied in numerous ways as a device for air acceleration. A major interest of all these works has been concentrated on achieving higher efficiency and producing higher jet velocities. These studies considered alternative geometries, different voltage waveforms etc., yet none of these studies tackle the inherently inefficient process of force creation and actuation in a DBD. Air acceleration has been attributed to the electric force that switches direction on each voltage half cycle (that is due to the nature of the discharge mechanism) yet has a forward resulting force. The present thesis considers the phenomenon of memory charge accumulation on the dielectric surface and reasons that the backward force in the second half cycle can be reversed by further migration of the memory charges to an added exposed anode. Hence a novel 3-electrode configuration is presented. Flow velocity investigations showed a 27% improvement in efficiency in comparison with the traditional 2-electrode actuator. This meant a 0.4m/s gain along the velocity profile. During the investigation process, a new discharge mechanism was encountered. This was characterized by the double discharge lines along the exposed electrode edges while in the presence of a \"floating\" encapsulated electrode.Tendo ganho popularidade na última década, a descarga de barreira dielétrica (DBD) foi estudada de várias maneiras como um dispositivo para aceleração do ar e controle aerodinâmico. Um grande interesse de todos esses trabalhos foi concentrado em alcançar maior eficiência e produzir maiores velocidades de jato. Alguns desses estudos consideraram geometrias alternativas, diferentes formas de onda de tensão, etc., mas nenhum desses estudos aborda o processo inerentemente ineficiente de criação e atuação da força em um DBD. A Aceleração do ar tem sido atribuída à força elétrica que muda de direção em cada meio ciclo (que é devido à natureza do mecanismo de descarga), mas que tem uma força resultante para a frente. A presente tese considera o fenômeno de acumulação de carga de memória na superfície dielétrica e raciocina que a força contraria no segundo meio ciclo da descarga pode ser revertida por migração dessas cargas de memória para um ânodo adicional exposto. Assim, uma nova configuração de 3 eletrodos é apresentada. Investigações de velocidade do fluxo mostraram uma melhoria de 27% na eficiência em comparação com o tradicional atuador de 2 eletrodos. Isso significou um ganho de 0,3 m/s ao longo do perfil de velocidade. Durante o processo de investigação, foi encontrado um novo mecanismo de descarga. Isso foi caracterizado por uma dupla descarga ao longo das bordas do eletrodos expostos, enquanto na presença de um eletrodo encapsulado \"pendurado\".
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Stanfield, Scott Alan II. "A SPECTROSCOPIC INVESTIGATION OF A SURFACE-DISCHARGE-MODE, DIELECTRIC BARRIER DISCHARGE." Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1261582116.
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Elam, Dana. "A direct numerical simulation of dielectric barrier discharge (DBD) plasma actuators for turbulent skin-friction control." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/49964/.
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Turbulent skin-friction control is the subject of much research and the use of transverse (spanwise) oscillating motions offers the means of obtaining a significant reduction in skin-friction. Dielectric barrier discharge (DBD) actuators can be used to generate spanwise oscillating waves but the difficulty in placing a sensor in the area of plasma gives rise to problems in recording near-wall velocities. A modified version of the Shyy et al. (2002) DBD model was integrated into a direct numerical simulation (DNS). This numerical model was used in a series of two-dimensional simulations, in initially quiescent ow, and the results were compared to results reported from experimental investigations. A close affinity was found confirming that the DBD model is satisfactory. Both a temporal and a spatial, spanwise oscillating ow were investigated. Only one plasma profile was investigated. Three actuator spacings were investigated. Only the largest actuator spacing resulted in a gap between each plasma profile that was larger than the plasma profile width itself. A spatially uniform plasma configuration produced larger DR% than spanwise wall oscillation for both spatial and temporal waves, maximum DR = 51% compared to a DR = 47% for a spanwise wall oscillation. Increased skin-friction reductions originated from the displacement of the Stokes layer. The spatial wave produced lower skin-friction values than temporal waves for all the configurations. For both spatial and temporal waves the performance of the discrete configurations in producing an overall skin-friction reduction decreased with increasing actuator spacing. Using both temporal and spatial waves, the configuration with the largest spacing, which is relatively small, did not produce a drag reduction for any case that was tested.
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Lovascio, Sara. "Cold Plasma deposition of organosilicon films with different monomers in a dielectric-barrier discharge." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00815260.
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Cette thèse porte sur une étude fondamentale sur le dépôt des couches minces d'organosiliciés par des Décharges à Barrière Diélectrique (DBD), un procédé très intéressant pour l'application aux textiles. La plupart des dépôts des couches d'oxyde de silicium sont déposées à partir du précurseur hexaméthyle silixone (HMDSO).De plus très peu d'études sont consacrées aux mécanismes de dépôt des couches à la pression atmosphérique. Dans cette étude les propriétés des couches minces déposées par DBD alimentées par Ar/HMDSO/O2, Ar/PMDSO (pentaméthyldisiloxane)/O2 et Ar/TMDSO (tetraméthyldisiloxane)/O2, avec différentes proportions de l'oxygène, ont été confrontées aux analyses, par GC-MS, des gaz sortant du réacteur. Nous avons trouvé que l'ajout d'O2 au gaz d'alimentation n'améliore pas l'activation du précurseur organosilicié, même s'il augmente la puissance injectée. En revanche il influence fortement la composition chimique des dépôts et favorise une forte réduction de la concentration des sous-produits dans le gaz sortant du réacteur. Sans ajout de l'O2, des couches minces obtenues contiennent beaucoup de carbone , avec rétention de la structure du précurseur de départ. En réduisant le nombre de -CH3 dans le précurseur (HMDSO>PMDSO>TMDSO), le nombre et l'abondance des sous-produits détectés dans le gaz sortant du réacteur diminuent fortement. Il semblerait que les unités de répétition diméthylsiloxane et hydrométhylsiloxane jouent un rôle important dans l'oligomérisation des trois précurseurs. Différents mécanismes d'activation, ainsi que différents procédés de formation des groupes Si-OH dans les dépôts, ont été proposés pour les trois précurseurs.
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Santos, Alessandro Luiz Ribeiro dos [UNESP]. "Estudo de polímeros comerciais tratados a plasma em pressão atmosférica." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/91830.
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Materiais poliméricos têm sido amplamente utilizados em várias áreas tecnológicas e biomédicas, devido às suas excelentes propriedades mecânicas, térmicas e elétricas. No entanto, estes materiais têm baixa energia de superfície e, portanto, não aderem facilmente a outros materiais. Por isso, para muitas aplicações é necessário modificar a superfície do polímero, a fim de aumentar a sua energia de superfície. Tratamentos a plasma à pressão atmosférica têm sido muito utilizados para modificar as propriedades superficiais de polímeros comerciais, devido aos baixos custos do processo. Este trabalho apresenta os resultados do tratamento de tereftalato de polietileno (PET), poliuretano (PU) e de politetrafluoretileno (PTFE) em plasma de descargas com barreira dielétrica (DBD) em ar, nitrogênio e argônio, à pressão atmosférica. As superfícies tratadas foram caracterizadas por medidas de ângulo de contato, espectroscopia de fotoelétrons de raios-X (XPS) e microscopia de força atômica (AFM). A superfície polimérica, modificada nas DBD a pressão atmosférica, mostraram uma redução significativa no ângulo de contato da água, embora uma recuperação parcial da molhabilidade ocorresse nos primeiros dias após o tratamento. Todavia, a recuperação foi insuficiente para que as amostras tratadas recuperassem a sua molhabilidade original. Análises de XPS mostraram um aumento na concentração de oxigênio na superfície, devido à formação de grupos polares, tais como C-O e OC= O. Um pequeno aumento na concentração de nitrogênio também foi observada. Imagens de AFM mostraram um aumento da rugosidade de polímeros tratados, decorrentes da interação física entre as espécies geradas na descarga e a superfície do polímero. A superfície ativada e a elevada tensão superficial dos polímeros tratados devem levar a um aumento da aderência do polímero.
Polymeric materials have been widely used in various biomedical and technological applications, due to their excellent mechanical, thermal and electric properties. However, these materials have low surface energy, and thus not easily adhere to other materials. Therefore, for many applications it is necessary to modify the polymer surface in order to increase its surface energy. Plasma treatments at atmospheric pressure have been frequently used to modify the surface properties of commercial polymers, due to their low process costs. This work reports the results of polyethylene terephthalate (PET), polyurethane (PU) and polytetrafluoroethylene (PTFE) treatments in plasma by dielectric barrier discharges (DBDs) in air, nitrogen and argon at atmospheric pressure. The plasma-modified surfaces were characterized by contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The polymer surface, modified by DBD at atmospheric pressure, showed a significant decrease in water contact angle although a partial recovery of the surface wettability occurred during the first few days after the treatment. However, the process of hydrophobic recovery was insufficient for complete recovering of the samples original wettability. XPS analysis showed an increase of the oxygen concentration on the surface, due to the formation of polar groups, such as C-O and OC= O. A small increase in the concentration of nitrogen was also observed. AFM images exhibit an increased roughness of the treated polymers because of the physical interaction between the species generated in the discharge and the polymer surface. The activated surface and high surface tension of treated polymers should promote an enhancement of the polymer adhesion to paints and coatings.
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Rampa, Federico. "Trattamento plasma assistito di acqua con una sorgente Dielectric Barrier Discharge (DBD): analisi delle specie reattive prodotte e potere battericida." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11812/.
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La proliferazione di batteri in liquido è una problematica che riguarda anche le acque di fiumi e mari. In questo progetto di tesi sperimentale si indagherà un trattamento plasma assistito diretto di acqua sintetica riprodotta in laboratorio con l’obiettivo di ottenere un effetto battericida sul liquido contaminato. L’acqua trattata verrà analizzata chimicamente, in particolare si andranno a misurare i TRO (Total Residual Oxidant, composti dell’ossigeno derivanti dalla parziale ozonizzazione dell’acqua) che dovranno essere presenti in quantità minori di 0,1 mg/l.
Il dispositivo utilizzato per i test biologici è una sorgente di tipologia DBD (Dielectric Barrier Discharge) indiretto. Gli elettrodi della sorgente sono separati dal solo strato di materiale dielettrico e uno di questi è composto da una rete metallica in acciaio inossidabile. Il plasma si forma tra le maglie della rete e induce la formazione di specie reattive, radiazioni UV, particelle cariche, campi elettromagnetici e calore. Ciò che raggiunge la soluzione contaminata è l’afterglow del plasma, ovvero tutte le specie reattive a lunga vita prodotte dalla ionizzazione dell’aria e dalle radiazioni UV. La sorgente è stata dapprima caratterizzata elettricamente studiando le forme d’onda di tensione e corrente a determinate condizioni operative. Il liquido da trattare è contaminato con il batterio Escherichia coli.
è emerso che in tutti i casi testati i livelli degli ossidanti sono entro il limite prestabilito di 0,1 mg/l. Il trattamento plasma in soli 10 secondi è responsabile di una decontaminazione parziale del batterio E. coli. Da ulteriori studi si potranno trovare delle condizioni tali da inattivare totalmente la carica batterica presente date le grandi potenzialità di questo trattamento.
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Santos, Alessandro Luiz Ribeiro dos. "Estudo de polímeros comerciais tratados a plasma em pressão atmosférica /." Guaratinguetá : [s.n.], 2010. http://hdl.handle.net/11449/91830.
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Resumo: Materiais poliméricos têm sido amplamente utilizados em várias áreas tecnológicas e biomédicas, devido às suas excelentes propriedades mecânicas, térmicas e elétricas. No entanto, estes materiais têm baixa energia de superfície e, portanto, não aderem facilmente a outros materiais. Por isso, para muitas aplicações é necessário modificar a superfície do polímero, a fim de aumentar a sua energia de superfície. Tratamentos a plasma à pressão atmosférica têm sido muito utilizados para modificar as propriedades superficiais de polímeros comerciais, devido aos baixos custos do processo. Este trabalho apresenta os resultados do tratamento de tereftalato de polietileno (PET), poliuretano (PU) e de politetrafluoretileno (PTFE) em plasma de descargas com barreira dielétrica (DBD) em ar, nitrogênio e argônio, à pressão atmosférica. As superfícies tratadas foram caracterizadas por medidas de ângulo de contato, espectroscopia de fotoelétrons de raios-X (XPS) e microscopia de força atômica (AFM). A superfície polimérica, modificada nas DBD a pressão atmosférica, mostraram uma redução significativa no ângulo de contato da água, embora uma recuperação parcial da molhabilidade ocorresse nos primeiros dias após o tratamento. Todavia, a recuperação foi insuficiente para que as amostras tratadas recuperassem a sua molhabilidade original. Análises de XPS mostraram um aumento na concentração de oxigênio na superfície, devido à formação de grupos polares, tais como C-O e OC= O. Um pequeno aumento na concentração de nitrogênio também foi observada. Imagens de AFM mostraram um aumento da rugosidade de polímeros tratados, decorrentes da interação física entre as espécies geradas na descarga e a superfície do polímero. A superfície ativada e a elevada tensão superficial dos polímeros tratados devem levar a um aumento da aderência do polímero.Abstract: Polymeric materials have been widely used in various biomedical and technological applications, due to their excellent mechanical, thermal and electric properties. However, these materials have low surface energy, and thus not easily adhere to other materials. Therefore, for many applications it is necessary to modify the polymer surface in order to increase its surface energy. Plasma treatments at atmospheric pressure have been frequently used to modify the surface properties of commercial polymers, due to their low process costs. This work reports the results of polyethylene terephthalate (PET), polyurethane (PU) and polytetrafluoroethylene (PTFE) treatments in plasma by dielectric barrier discharges (DBDs) in air, nitrogen and argon at atmospheric pressure. The plasma-modified surfaces were characterized by contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The polymer surface, modified by DBD at atmospheric pressure, showed a significant decrease in water contact angle although a partial recovery of the surface wettability occurred during the first few days after the treatment. However, the process of hydrophobic recovery was insufficient for complete recovering of the samples original wettability. XPS analysis showed an increase of the oxygen concentration on the surface, due to the formation of polar groups, such as C-O and OC= O. A small increase in the concentration of nitrogen was also observed. AFM images exhibit an increased roughness of the treated polymers because of the physical interaction between the species generated in the discharge and the polymer surface. The activated surface and high surface tension of treated polymers should promote an enhancement of the polymer adhesion to paints and coatings.
Orientador: Konstantin Georgiev Kostov
Coorientador: Roberto Yzumi Honda
Banca: Konstantin Georgiev Kostov
Banca: Rogério Pinto Mota
Banca: Gilberto Petraconi Filho
Mestre
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McElligott, Kristine L. "Control of flow separation from the deflected flap of a high-lift airfoil using multiple dielectric barrier discharge (DBD) plasma actuators." Connect to resource, 2010. http://hdl.handle.net/1811/45388.
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Diop, Mame Andallah. "Alimentation sans transformateur pour dispositif de décharge à barrière diélectrique (DBD)." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30092/document.
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Cette thèse porte sur le développement d'une structure d'alimentation sans transformateur pour des décharges à barrière diélectrique (DBD). Une DBD est une charge permettant d'obtenir des plasmas froids à la pression atmosphérique. Ce dispositif est fortement capacitif et son alimentation doit délivrer plusieurs kilovolts pour allumer et entretenir la décharge. Cette haute tension est classiquement obtenue à l'aide d'un transformateur élévateur. Dans une première partie, nous montrons que les éléments parasites du transformateur impactent fortement le transfert d'énergie vers la décharge. C'est pourquoi dans une seconde partie, nous proposons une nouvelle topologie d'alimentation sans transformateur élévateur. Les caractéristiques fondamentales et le dimensionnement de notre alimentation sont obtenus par une analyse théorique. Dans cette topologie, les interrupteurs sont directement connectés à la DBD ; ils doivent donc supporter des tensions de plusieurs kilovolts. Il y a encore quelques années, il n'existait pas de semi-conducteur capable de supporter ce niveau de tension, à moins d'utiliser des interrupteurs fonctionnant à très basse fréquence. De récents progrès sur les matériaux semi-conducteurs ont permis d'élaborer des transistors et des diodes à base de carbure de silicium (SiC) capables de supporter des tensions allant jusqu'à 10 kV. Ce niveau de tension est tout à fait compatible avec la topologie d'alimentation proposée ici.Nous consacrerons la troisième partie du manuscrit à la mise en œuvre de notre convertisseur. Ce dernier, conçu à base de semi-conducteurs SiC, est fonctionnel et permet d'allumer une décharge. Cependant le fonctionnement initialement prévu est fortement affecté par la présence des capacités parasites notamment celles des interrupteurs. Nous détaillerons le rôle de chacune d'entre elles. Nous proposerons enfin des solutions permettant d'améliorer le transfert de puissance : mise en série de semi-conducteurs basses tensions, utilisation sur DBD de forte puissanceThis thesis focuses on the development of a dielectric barrier discharge (DBD) transformerless power supply. A DBD can produce cold plasma at atmospheric pressure. This device is a capacitive load, which must be supplied by a high voltage alternative source. This high voltage is classically obtained by amplifying a low level voltage with a step up transformer. In the first part, we show that the parasitic elements of the transformer limit the power transfer to the DBD load. This is why, in a second part, we propose a new topology without step-up transformer. A theoretical study of the converter allows to size our power supply and to deduce the fundamental characteristics of the latter. In our topology, the power switches are directly connected to the high voltage. A few years ago, it was inconceivable to connect directly a transistor to a high level of voltage (5kV), unless using very low frequency switches. Recent progress on semiconductor devices led to the development of transistors and diodes based on silicon carbide (SiC), which are able to hold up to 10kV. This voltage level is compatible with our topology.In the third part, we focus on the realization of our transformerless power supply and its operation. Our power supply based on 10 kV SiC semiconductors can ignite the discharge; however the parasitic capacitance and particularly those of the switches affect the power transfer. The role of each one of them is analyzed in detail.In the last part we propose solutions to improve the power delivered by this supply: series connection of lower voltage switches, supplying a high power DBD
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Chhatiawala, Nihar H. "Case Study: The Commercial Potential of Dielectric Barrier Discharge Plasma Actuators for Active Flow Control in Wind Turbines." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1536947431190003.
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Bonafè, Giacomo. "Simulation of the chemistry induced in air by a dielectric barrier discharge plasma source and experimental validation using optical absorption spectroscopy." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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The dielectric barrier discharge consists in a plasma discharge developed in the volume between two metal electrodes covered by a dielectric material. DBDs setup are remarkably good and cheap tools to generate non-equilibrium plasmas at atmospheric pressure, characterized by highly energetic electrons in a background gas whose temperature is close to room temperature. The produced non-thermal plasma represents an environment where extremely energetic chemical processes can occur at low/medium temperatures, making them suitable for biomedical applications.
Among the biomedical applications of DBD sources, this thesis concerns bacterial decontamination, focusing on the chemical/physical characterization of plasma. The antimicrobial efficacy of the plasma treatment is connected with the chemical-physical species that plasma is able to generate in air, such as reactive oxygen and nitrogen species (RONS). In order to achieve an optimal bacterial reduction, it is necessary to optimize the production of RONS species.
The study of plasma-induced chemistry is very complex due to the multitude of physical states that characterizes the plasma and due to the extremely fast kinetics of the species involved in the plasma-assisted reactions. Consequently, a computational modelling of the plasma is indispensable to understand all the chemical phenomena induced simultaneously by plasma during the treatment. A fluid method implemented in PLASIMO was chosen to simulate the plasma; which was developed at the Eindhoven University of Technology. During my thesis project, I spent a few months at the Eindhoven University of Technology where I performed several simulations on the chemistry induced by a DBD plasma source in air. The results of the simulations have been experimentally validated in the Raizer Plasma Diagnostic Lab at the University of Bologna via optical absorption spectroscopy, which allows to characterize the gas-phase chemistry of the plasma via Lambert-Beer law.
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Djibrillah, Mahamat Abakar. "Éléments de conception d’un générateur électrique pour l’alimentation d’un dispositif à décharge à barrière diélectrique (DBD)." Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0028/document.
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Ce travail traite de la conception de générateur alimentant une lampe DBD destinée à la production de rayonnement UV. Cette alimentation doit permettre un contrôle efficace du rayonnement, grâce aux degrés de liberté apportés par le contrôle du générateur (fréquence, amplitude du courant injecté dans la lampe). Le modèle électrique de la lampe est utilisé pour prédire l’impact des caractéristiques du générateur sur le rayonnement UV produit. Une synthèse des interrupteurs de puissance du convertisseur statique permettant le contrôle du courant injecté est proposée et des solutions d’implémentation sont étudiées. Une démarche de conception en vue de l’optimisation du transformateur haute tension est proposée, notamment en ce qui concerne la valeur de ses éléments parasites. L’ensemble de ces travaux est étayé par des réalisations expérimentalesThis work presents the concept of a generator supplying a DBD lamp for UV radiation production purpose. This supply permits effective control of radiation based on degree-of-freedom provided by generator control system (lamp current frequency and ampli-tude). Lamp electrical model is used to predict the impact of power source characteristics on the produced UV radiation. A synthesis of the switching devices of power converter for current lamp control is pro-posed and the implemented solutions are studied. A design procedure for high voltage transformer optimization is proposed in particular concerning parasitic elements. The entire work is supported by experimentations
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Droubi, Ashraf El. "Efeito da descarga de barreira dielétrica no escoamento do ar sobre um cilindro." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-12032012-162034/.
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Fluidos em uma descarga brilhante à pressão atmosférica usando uma barreira de dielétrico DBD atraiu o interesse das comunidades de termo-dinâmica, fluido-dinâmica, e comunidades de controle. Este trabalho investiga os efeitos de um atuador de plasma operando numa voltagem e frequência de 8 kV e 4.4 kHz sobre a curva do Cp de um cilindro de PVC em baixa velocidade de escoamento. O experimento foi repetido com o atuador em vários ângulos no cilindro. Os resultados mostram uma aceleração do escoamento junto com um atraso da separação. Esses efeitos são maiores quando o atuador é posicionado num ângulo mais próximo da região da separação.Fluids in a dielectric barrier DBD glow discharge at atmospheric pressure attracted the interest of the communities of thermo and fluid dynamics as well as control. This dissertation investigates the effects of a plasma actuator operating at 8 kV and 4.4 kHz, on the Cp curve of a PVC cylinder in a low velocity airflow. The experiment was repeated with the actuator at various angles. The results show an acceleration of the flow accompanied with a delay of the flow separation. These effects were shown to be larger when the actuator was positioned at an angle closer to the region of separation.
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Souza, Ivan Alves de. "Descarga em barreira diel?trica: constru??o de um reator DBD e caracteriza??o mediante an?lises ?pticas e el?tricas do plasma produzido." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15710.
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Previous issue date: 2013-06-21The plasma produced by Dielectric Barrier Discharge (DBD) is a promising technique for producing plasma in atmospheric pressure and has been highlighted in several areas, especially in biomedical and textile industry, this is due to the fact that the plasma generated by DBD not reaches high temperatures, enabling use it for thermally sensitive materials. But still it is necessary the development of research related to understanding of the chemical, physical and biological interaction between the non-thermal plasma at atmospheric pressure with cells, tissues, organs and organisms. This work proposes to develop equipment DBD and characterize it in order to obtain a better understanding of the process parameters of plasma production and how it behaves under the parameters adopted in the process, such as distance, frequency and voltage applied between electrodes. For this purpose two techniques were used to characterize distinct from each other. The first was the method of Lissajous figures, this technique is quite effective and accurately for complete electrical characterization equipment DBD. The second technique used was Optical Emission Spectroscopy (EEO) very effective tool for the diagnosis of plasma with it being possible to identify the excited species present in the plasma produced. Finally comparing the data obtained by the two techniques was possible to identify a set of parameters that optimize the production when combined DBD plasma atmosphere in the equipment was built precisely in this condition 0.5mm-15kV 600Hz, giving way for further work
O plasma produzido por Descarga em Barreira Diel?trica (DBD) ? uma promissora t?cnica de produ??o de plasma em press?o atmosf?rica e vem se destacando em diversas ?reas, principalmente na biom?dica e ind?stria t?xtil, isso se deve ao fato de que o plasma gerado por DBD n?o atinge grandes temperaturas, possibilitando utiliz?-lo em materiais termicamente sens?veis. Por?m, ainda faz-se necess?rio o desenvolvimento de pesquisas relacionadas ao dom?nio e compreens?o dos mecanismos qu?micos, f?sicos e biol?gicos da intera??o entre o plasma n?o t?rmico ? press?o atmosf?rica com c?lulas, tecidos, ?rg?os e microrganismos. O presente trabalho se prop?s a desenvolver um equipamento DBD e caracteriz?-lo para assim obter um maior conhecimento dos par?metros do processo de produ??o de plasma e de como este se comporta mediante os par?metros adotados no processo, tais como dist?ncia, frequ?ncia e voltagem aplicada entre eletrodos. Para este fim foram utilizadas duas t?cnicas de caracteriza??o bem distintas entre si. A primeira foi o m?todo das figuras de Lissajous, essa t?cnica ? bastante eficaz e precisa para uma completa caracteriza??o el?trica de equipamentos DBD. A segunda t?cnica usada foi Espectroscopia de Emiss?o ?ptica (EEO) uma ferramenta bastante eficaz para o diagn?stico de plasma sendo poss?vel com ela identificar as esp?cies excitadas presentes no plasma produzido. Por fim confrontando os dados obtidos mediante as duas t?cnicas foi poss?vel identificar um conjunto de par?metros que quando associados aperfei?oam a produ??o do plasma DBD atmosf?rico no equipamento constru?do isso ocorreu mais precisamente na condi??o 0,5mm-600Hz-15kV, dando rumo para trabalhos futuros
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Bonnin, Xavier. "Alimentation électrique des dispositifs de décharge à barrière diélectrique." Phd thesis, Toulouse, INPT, 2014. http://oatao.univ-toulouse.fr/13645/1/bonnin.pdf.
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Les dispositifs DBD se répandent dans un grand nombre d’applications industrielles. Utilisés depuis plus de 150 ans pour la production d’ozone afin de décontaminer l’eau à grande échelle, ils ont depuis la fin du XXème siècle investi les domaines du traitement de surface polymère, du dépôt de couche mince sur substrat et de l’émission lumineuse pour la décontamination ainsi que la médecine. Ces dispositifs sont mis en oeuvre avec un générateur électrique dont les caractéristiques impactent fortement la qualité de la décharge. Ce travail s’inscrit en partie dans le cadre du développement d’une application de traitement de surface à pression atmosphérique. Il aborde la problématique de l’augmentation de la vitesse de dépôt de couche mince au travers des paramètres de l’alimentation électrique. Plus précisément, ce travail s’intéresse aux apports d’une alimentation en courant rectangulaire et aborde également les problématiques liées à la conception et à la fabrication de ce convertisseur. En particulier, une grande attention est portée sur l’étude du transformateur élévateur, car au travers de ses éléments parasites capacitifs, ce dernier peut limiter le transfert de puissance entre la source électrique et le dispositif DBD. Un deuxième aspect de cette étude consiste à entrevoir l’intérêt que revêtent deux convertisseurs statiques dédiés à l’alimentation de dispositifs DBD. Le premier consiste en une alimentation résonante en régime de conduction discontinue dont la particularité est de posséder trois degrés de liberté (fréquence, tension d’entrée et largeur d’impulsion), ce qui lui confère un intérêt exploratoire. Le second convertisseur consiste en une alimentation résonante haute tension et haute fréquence permettant l’éviction du transformateur élévateur, et mettant en oeuvre des interrupteurs au nitrure de gallium (GaN) afin d’atteindre une fréquence de fonctionnement supérieure au mega-Hertz avec un faible niveau de pertes.
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Bartusch, Matthias. "Oberflächenmodifizierung von textilem ultrahochmolekularen Polyethylen mittels Dielektrischer Barriereentladung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-209633.
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Textiles ultrahochmolekulares Polyethylen (UHMWPE) besitzt, aufgrund seiner außerordentlich hohen Molmasse und einem kristallinen Anteil von mehr als 80 %, exzellente spezifische Reißfestigkeiten sowie sehr gute Beständigkeiten gegenüber biologischen, chemischen und physikalischen Einflüssen, wodurch es sich für den Einsatz in Schutztextilien, als textiler Träger für funktionelle Partikel, zur Faserverstärkung in Kunststoffen für hochbelastbare Bauteile und auch zur Herstellung hochwertiger, technischer Textilmembranen anbietet. Voraussetzung für diese Applikationen ist ein hohes Wechselwirkungsvermögen der Fasergrenzflächen.
Im Rahmen dieser Dissertationsschrift wurden systematisch die Möglichkeiten zur Oberflächenaktivierung von textilem UHMWPE mittels Atmosphärendruckplasma (ADP) untersucht und Eigenschafts-Wirkungsbeziehungen verschiedener Einflussparameter, u. a. Plasmaleistung, Elektrodenabstand, Behandlungsintensität, aufgeklärt. Dabei lag ein besonderes Augenmerk auf den textilen Eigenheiten des Materials und der dadurch stark beeinflussten Durchdringung des Plasmas. Entsprechend wurden umfangreiche Messreihen zu chemischen und physikalischen Veränderungen der Faseroberfläche erstellt, um schließlich eine industrielle Nutzbarkeit der ADP-Behandlung ableiten zu können. Hierzu wurden auch zwei weitere Verfahren vergleichend begutachtet und in Kooperation mit dem Leibniz-Institut für Polymerforschung Dresden e.V. eine mögliche Anwendung aktivierter UMHWPE-Garne als Träger für magnetisierbare Nanopartikel betrachtet.
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Huang, Guangming. "Dielectric barrier discharges for ozone generation." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27626.
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Non-thermal plasma discharges, particularly dielectric barrier discharges (DBDs), are the most common method of ozone generation. The aim of this research was to optimize the micro-discharges in DBDs, to improve ozone generation efficiency. The electrical characteristics of DBDs were researched, and the effects of the physical and electrical parameters of DBDs on ozone generation were investigated. Four DBD based ozone reactors, including plate configuration and cylindrical configuration, were designed and developed. Three major energization modes, including transient (40 ms) AC power supply, continuous AC power supply and pulsed power supply, were used for the investigation of ozone generation performance. Under transient AC energisation in oxygen, it was found that the ozone generation efficiency at 2 bar absolute was 217 g/kWh, increased by 31% compared with that at 1 bar absolute. The ozone generation efficiency was found to increase with decreasing E/N in the range from 126 Td to 185 Td. Under continuous AC energisation, the ozone concentration was found to increase as the gas flow rate decreased (from 1 L/min to 0.4 L/min) or applied voltage was increased (from 3.5 kV to 6 kV). Under optimized conditions, the highest ozone concentration obtained was 271 g/Nm3, which is promising in comparison with previously-published data. The ozone generation efficiency was found to reduce as the ozone concentration increased above 30 g/Nm3. Furthermore, it was found that the AC energization frequency had no obvious effect on the behaviour of micro-discharges, or on the ozone generation efficiency. Pulsed DBDs for ozone generation was found to be less efficient than continuous AC energisation, for the conditions investigated herein. This research has achieved the desired combination of high ozone generation efficiency at high ozone concentration (>150 g/Nm3), based on DBDs The curve of ozone generation efficiency versus ozone concentration achieved shows more efficient performance than that in the literature: at the typical industrial ozone concentration of 150 g/Nm3 for waste water treatment, the ozone generation efficiency in this work was ~8.2 kWh/kg, ~20% higher than that in the literature.
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Nessim, Christine. "Surface modification of powders using dielectric barrier discharges." Thèse, Université de Sherbrooke, 2008. http://savoirs.usherbrooke.ca/handle/11143/1832.
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Le traitement de surface des poudres par plasma hors-équilibre est un outil rapide et indispensable au développement de nouvelles applications pour les poudres traitées. Dans un domaine tel que la synthèse des poudres pyrophoriques métalliques, ou l'ignition est instantanée en cas de non passivation et de contact avec l'air, un traitement par un plasma hors-équilibre permet de modifier les propriétés de surface des poudres afin d'obtenir des poudres moins réactives à basse température tout en gardant leur caractéristique énergétique à haute température. Autre domaine, comme le changement de la mouillabilité des poudres est très recherché. L'objectif de ce travail est de développer des nouvelles techniques pour le traitement de surface des poudres micro ou nanométriques en utilisant les techniques de plasma hors-équilibre. L'avantage de cette approche est de pouvoir modifier les propriétés de surface de ses dites poudres sans affecter les propriétés globales comme par exemple la structure cristalline, taille des poudres et composition chimiques. En fait, les décharges à barrière diélectrique opérant à pression atmosphérique sont idéales pour traiter la surface des poudres sans changer leur structure car ils produisent des electrons énergétiques pour exciter les espèces moléculaires et atomiques à basse température. Aussi, l'opération à pression atmosphérique permet l'integration de l'unité de traitement de surface avec l'unité de synthèse en évitant l'utilisation des systèmes de vide assez dispendieux et difficile à maintenir. Dans ce travail, des expériences sur la déposition ainsi que sur la fonctionnalisation ont été menés en utilisant deux designs de torche à barrière diélectrique. Pour la déposition, des précurseurs tels que l'éthylène, butadiène, pyrrole et acétylène ont été utilisé pour former des couches organiques sur des poudres micro ou nanométriques. D'autres précurseurs à base de silicium comme le tétraéthyloxysilicates ou l'hexaméthyldisiloxane ont été utilisés pour former des dépôts de nature inorganiques ( SiO[indice]x ) ou organiques ( SiO[indice]x C[incice]y H[indice]z ) sur des poudres métalliques ou d'oxydes. Pour les tests de fonctionnalisation, la surface a été modifiée par des décharges, d'hélium-air, hélium-oxygène et hélium-azote. Dans les experiences de déposition, les effets de temps de résidence, de la densité de puissance, de l'injection en mode pulsé ou dans la région après plasma ont été étudié. Quelques tests ont été réalisés pour établir l'effet de la température des gaz et des poudres sur le dépôt. Quand à la fonctionnalisation, l'effet de la densité de puissance, des types de gaz et de temps de résidence ont été examinés. Pour les dépôts réalisés en utilisant des précurseurs organiques ou à base de silicium, l'utilisation de mode pulsé ainsi que l'injection dans la région après plasma ont formé des dépôts dense. Dans la plupart des autres dépôts effectués dans la décharge, des poudres ont été formées. Le faite de chauffer les poudres avant leur injection a augmenté leur dispersion. Finalement, la fonctionnalisation des poudres de polymères ont permis leur mouillabilité pour un débit assez élevé (20g/min) Le vieillissement des poudres n'ont pas dépassé le 25% pour une période de 60 jours dépendamment de leur méthode d'entreposage. Il ressort donc de ce travail que les décharges à barriere diélectriques sont capables de modifier les surfaces des poudres selon les conditions et le design appliqués.
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Seidelmann, Lukas Josef Wilfried. "Atmospheric pressure dielectric barrier discharges for the surface modification of polypropylene." Thesis, Manchester Metropolitan University, 2015. http://e-space.mmu.ac.uk/608794/.
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Polypropylene films are widely used as packaging materials for foodstuffs, since they offer excellent barrier properties against polar substances, high elasticity, mechanical strength, transparency and chemical stability. However, the relatively low surface energy of polypropylene represents a major issue for the adhesion of printing inks and labels. To improve printability it is necessary to perform a surface activation process. In the presented work, the atmospheric pressure dielectric barrier discharge (DBD) in nitrogen is investigated as a surface treatment method to increase the surface energy of biaxially orientated polypropylene foils. This technology creates a non-thermal plasma by applying strong electrical fields to a gas between two electrodes. The reactive species of the plasma forms new electronegative chemical groups on the surface and also etches the surface of the substrate. Both effects lead to an increase of the surface energy of the plasma treated polymer films. The crosslinking of polymer chains is also a possible effect caused by the plasma treatment. A new plasma rig was designed for this project, including a closed plasma chamber, two different parallel electrode configuration (flat or sawtooth electrodes) and a reel-to-reel system for the transport of the polypropylene foil. The designed system allows to adjust the sizes of the gas gap and the thickness of the dielectric. In addition, the plasma chamber can be filled with every gas or gas mixture wanted. A D-optimal design of experiments approach was utilised to study the influence of the power applied to the electrodes, the size of the gas gap and the thickness of the dielectric on the wettability of the treated polymer films. Furthermore, a flat electrode and a sawtooth electrode configuration are compared to each other. The findings of this work clearly indicate that the sawtooth electrode configuration is superior regarding the consumed electrical power and the wettability of the treated films. The optimal setting for the plasma treatment with the sawtooth electrode configuration are a low gas gap and a high power applied to the electrodes. The thickness of the dielectric has no influence on the wettability of the treated film. However, the increase of the dielectric thickness leads to an increase of the consumed power. These findings were transferred to an industrial process, where the polymer foils were treated in a nitrogen atmosphere with admixtures of CO2, N2O and C2H2 in the ppm range under the founded optimal conditions. A significant difference in the surface energies of these samples could not be identified by contact angles measurement, but all samples showed a significantly reduced hydrophobic recovery rate in comparison to samples treated by the in the industry more conventional plasma treatment in air. The DBD surface treatment in nitrogen is therefore an important improvement for the industrial production, because the treated packaging foils can be stored longer before they are processed further without the need to refresh the surface treatment. The low hydrophobic recovery of the samples treated in the nitrogen plasma is connected to an intensified crosslinking of the polymer chains on the surface of the treated polypropylene films.
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Defoort, Étienne. "Écoulement électro-aérodynamique d'un aérosol de gouttelettes d'eau dans un réacteur de type pointe-plaque en vue de la récupération de composés chimiques." Thesis, Poitiers, 2020. http://www.theses.fr/2020POIT2278.
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Les décharges couronnes DC et les décharges à barrière diélectrique dans l’air à pression atmosphérique sont souvent utilisées en chimie car elles ont la capacité de produire des réactions chimiques hors-équilibre. Dans certaines conditions, elles peuvent générer un écoulement appelé « vent ionique ». Dans cette thèse, l’effet de l’injection d’un brouillard de gouttelettes d’eau micrométrique dans de tels plasmas est étudié, pour être appliqué à la récupération d’espèce chimique volatile in situ. L’objectif est donc d’étudier la mise en mouvement de l’aérosol par la décharge et sa précipitation sur la paroi d’un réacteur de type pointe-plan, à l’aide d’un dispositif de Vélocimétrie par Image de Particules (PIV) à haute fréquence (20 kHz). Dans un premier temps, la mise en mouvement de l’air par le phénomène de vent ionique est décrite, cet écoulement présentant des propriétés qui dépendent fortement du signal électrique alimentant la décharge (amplitude, fréquence, forme d’onde). Dans un second temps, l’effet du brouillard de gouttelettes d’eau sur la décharge ainsi que l’écoulement du brouillard dans l’espace inter-électrodes sont analysés. On a ainsi pu démontrer que le déplacement des particules était majoritairement dû au vent ionique, mais que le phénomène de précipitation électrostatique n’était pas négligeable, surtout à proximité de la plaque et dans les régions éloignées du centre du jet. Enfin, la quantité d’eau récupérée est évaluée pour différentes configurations de décharges électriques. L’application du procédé à la chimie n’a pu aboutir du fait de l’instabilité de la décharge dans un réacteur fermé à cause du film d’eau, non désiré, se formant sur les paroisDC corona discharges and dielectric barrier discharges (DBD) in air at atmospheric pressure are often used in chemistry due to their capacity to produce non-equilibrium chemical reactions. Under certain conditions, they can generate a flow called “ionic wind”. In this thesis, the effect of injecting a mist of water droplets into such plasmas is studied and applied for in situ volatile chemical species gathering. The objective is to study the motion of the aerosol induced by the discharge and its precipitation on the plate wall of a point-to-plate reactor, by means of a Particles Image Velocimetry (PIV) device at high frequency (20 kHz). First, the acceleration of air by the ionic wind phenomenon is described, this flow exhibiting properties that strongly depend on the electrical signal supplying the discharge (amplitude, frequency and waveform). Secondly, the impact of the water droplets mist on the discharge and the mist flow in the gap between electrodes are analyzed. We demonstrated that the particle movement was mainly due to ionic wind, but that the electrostatic precipitation phenomenon was not negligible, especially close to the plate and in the area far away from the jet axis. Lastly, the amount of water gathered in different discharge setups is evaluated. Applying the process to chemistry did not succeed because the discharge was unstable in a closed reactor due to the water film that takes place on the wall of the reactor
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Höft, Hans [Verfasser]. "Characteristics of pulsed operated dielectric barrier discharges in molecular gas mixtures / Hans Höft." Greifswald : Universitätsbibliothek Greifswald, 2015. http://d-nb.info/1072434830/34.
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Rodríguez, Durán Iván. "Dielectric barrier discharges : a promising tool for the fabrication of anti-fogging coatings." Doctoral thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/66960.
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La « vue floue » typique des surfaces embuées peut être extrêmement frustrante. Des exemples tels que les lunettes qui s’embuent pendant l’activité physique, la condensation qui se forme à l’intérieur des fenêtres pendant l’hiver ou les miroirs qui se couvrent de buée pendant la douche le démontrent. En outre, la présence de buée sur les surfaces cause des effets néfastes dans certains secteurs d’activité comme l’industrie automobile (pare-brise et rétroviseurs), l’industrie optique (objectifs, caméras, télescopes et capteurs), l’industrie solaire (modules photovoltaïques), l’industrie alimentaire (emballages d’aliments) et le secteur médical (lunettes et endoscopes). Au cours de la dernière décennie, l’application de revêtements (super)hydrophiles a suscité un intérêt croissant, en raison de leur capacité d’atténuer les effets de la buée. Leur principe de fonctionnement repose sur l’utilisation de matériaux interagissant avec les gouttes d’eau pour en modifier leur morphologie, générant une couche mince d’eau sur la surface. Ainsi, la lumière incidente n’est pas dispersée et les effets de la buée sont amoindris. Jusqu’à présent, la plupart des techniques de dépôt explorées pour produire des revêtements (super) hydrophiles sont inaccessibles à la production de masse en raison de leur nature multiétape. Pour cette raison, l’exploration de techniques adaptées à ce type de production, telles que les décharges à barrière diélectrique à pression atmosphérique (AP-DBD), un type de procédé de dépôt chimique en phase vapeur assisté par plasma (AP-PECVD), est cruciale afin d’élargir l’utilisation des revêtements antibuée au-delà du laboratoire. Dans un procédé AP-PECVD contrôlé par des barrières diélectriques (AP-DBD), certains précurseurs inorganiques ou organométalliques (e.g., TiCl4, TiN, SiH4, Si2O(CH3)2) sont introduits entre deux électrodes parallèles avec un gaz vecteur (e.g., N2, Ar, He) à la pression atmosphérique, où ils se fragmentent à la suite d’interactions avec les espèces du plasma. Les fragments résultants réagissent les uns avec les autres ou avec le substrat afin de produire les espèces réactives requises au dépôt du revêtement. Les caractéristiques structurelles et fonctionnelles des revêtements PECVD (e.g., la rugosité de surface, la biocompatibilité, les propriétés optiques et de mouillage) dépendent des certains paramètres de dépôt, tels que la puissance dissipée dans la décharge, le type de décharge, la concentration de précurseurs et le débit de gaz. La possibilité de se procurer des échantillons de verre dotés de la propriété antibuée via APPECVD a été démontrée dans cette thèse. En contrôlant les paramètres de dépôt, les revêtements antibuée ont été préparés en utilisant du 1,3,5,7-tétraméthylcyclotétrasiloxane (Si4O4H4(CH3)4) et de l’oxyde nitreux (N2O) au moyen d’une DBD fonctionnant en N2 à la pression atmosphérique. Dans le cas des revêtements fabriqués dans des conditions statiques (aucun mouvement entre l’échantillon de verre et les électrodes), l’évaluation quantitative de la résistance à la buée (ASTM F 659-06) a révélé que les revêtements obtenus avec un rapport [N2O]/[TMCTS] ³ 30 ou avec une puissance dissipée ³ 0,25 W cm-2 sont antibuée (transmittance > 80%) en raison de leur nature hydrophile. La quantité de précurseur et d’oxydant injectée dans la décharge, exprimée par la somme « [N2O] + [TMCTS] », n’agissait que peu sur la performance antibuée. En l’absence de changements significatifs dans la rugosité de surface (Rrms et Ra étant compris entre 3 et 6 nm), l’origine de la performance antibuée a été attribuée à la chimie de surface. Couplé aux rapports O/Si (résultats XPS), un paramètre arbitraire, appelé « rapport d’embuage » a été défini en considérant les résultats FTIR pour expliquer les performances antibuée observées. On a pu constater qu’un rapport O/Si ≥ 2,3 couplé à un rapport d’embuage dans l’intervalle de 0-0,10, résultant de la présence de fonctionnalités hydrophiles, telles que les groupes silanol, hydroxyle, carboxyle or ester à la surface étaient nécessaires pour atteindre la propriété antibuée. Par ailleurs, les revêtements préparés dans des conditions dynamiques utilisant trois autres précurseurs aux structures différentes quant à la présence d’un cycle et au nombre de groupes Si-H et Si-CH3 (l’octaméthylcyclotétrasiloxane, le 1,1,3,3-tétraméthyldisiloxane et l’hexaméthyldisiloxane) n’étaient pas antibuée. Ce résultat porte à croire que la structure cyclique du TMCTS et la forte réactivité des liaisons Si-H est à l’origine de la formation de ces fonctionnalités hydrophiles et par conséquent, à la performance antibuée observée dans les verres traités en injectant du TMCTS dans la décharge plasma.Experience shows that the “blurred view” typical of fogged surfaces can be incredibly frustrating. Eyewear fogging up during physical activity, condensation forming on the inside of windows during the winter, or bathroom mirrors steaming up when taking a shower are some obvious examples. In addition to being upsetting, the fogging of surfaces has been reported to cause adverse effects on sectors of activity as diverse as the automotive industry (e.g., windshield glass and rearview mirrors), the optical industry (e.g., lenses, cameras, telescopes, and sensors), the solar industry (e.g., photovoltaic modules), the food industry (e.g., food packaging), and medicine (e.g., goggles and endoscopes). Over the last decade, interest has been growing in the application of hydrophilic and superhydrophilic coatings, as they can efficiently mitigate the effects of fogging by changing the morphology of fog drops. The working principle of a (super)hydrophilic surface is based on the use of materials producing a thin film of water on the solid surface on interaction with fog drops. As a result, incident light transmits without being scattered and the effects of fogging are minimized. Unfortunately, most of the deposition techniques used thus far for the fabrication of (super)hydrophilic coatings involves multiple steps, thus making their integration into mass production a challenging task. For this reason, the exploration of deposition techniques adapted for large-scale production is crucial to broaden the range of application of antifogging coatings beyond the laboratory. In this regard, numerous studies on the use of dielectric barriers in plasma enhanced chemical vapor deposition at atmospheric pressure (AP-PECVD) are strongly emerging to address this issue. In a typical AP-PECVD controlled by dielectric barriers, inorganic or organometallic precursors (e.g., TiCl4, TiN, SiH4, Si2O(CH3)2) are introduced between two parallel electrodes along with a carrier gas (e.g., N2, Ar, He) at atmospheric pressure where, on interaction with plasma species, undergo fragmentation. The resulting fragments can react with the substrate or with each other to produce short-lived species required for coating deposition. The structural and functional features of PECVD coatings (e.g., surface roughness, biocompatibility, wetting and optical properties) depend on several deposition parameters, including the power dissipated in the discharge, type of plasma discharge, precursor concentration, and the flow rate of gases. With this in mind, the feasibility of conferring fogging resistance to commercial glass samples via AP-PECVD has been demonstrated in this doctoral thesis. By appropriately controlling the deposition parameters, anti-fogging coatings were prepared using 1,3,5,7- tetramethylcyclotetrasiloxane (Si4O4H4(CH3)4) and nitrous oxide (N2O) by a dielectric barrier discharge operated in N2 at atmospheric pressure (AP-DBD). When coating deposition was conducted in static conditions, that is, with no relative movement between the glass sample and the electrodes, quantitative assessment of the fogging resistance (ASTM F 659-06 standard) revealed that coatings obtained under [N2O]/[TMCTS] ratios ³ 30 or under a dissipated power ³ 0.25 W cm-2 endowed glass samples with the anti-fogging property (transmittance > 80%), because of their hydrophilic nature. In terms of the [N2O] + [TMCTS] sum, the amount of TMCTS and N2O injected into the discharge did not appear to have a great impact on the anti-fogging performance. Indeed, as no significant changes in surface roughness were observed (Rrms and Ra were between 3 and 6 nm), the origin of the anti-fogging performance was attributed to the surface chemistry. To this end, an arbitrary parameter, called “fogging ratio”, was defined considering FTIR results to account for, along with O/Si ratios (XPS results), the observed anti-fogging performance. Fogging ratios in the 0-0.10 range coupled with O/Si ratios ³ 2.3, resulting from the presence of hydrophilic functionalities, such as silanol (Si-OH), hydroxyl (C-OH) carboxyl (COOH), and ester (COOR) groups at the coating surface were necessary to attain the anti-fogging property. Interestingly, coatings prepared in dynamic conditions using three other precursors with different structures and different number of Si-H and Si-CH3 groups; namely, octamethylcyclotetrasiloxane (OMCTS), 1,1,3,3-tetramethyldisiloxane (TMDSO), and hexamethyldisiloxane (HMDSO) were not fogging-resistant. This result leads us to believe that the cyclic structure of TMCTS in conjunction with the high reactivity of Si-H bonds is behind the formation of the above-mentioned hydrophilic functionalities, and thus the antifogging performance of TMCTS-coated glasses.
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Tschiersch, Robert [Verfasser]. "The role of surface charges and negative ions for dielectric barrier discharges / Robert Tschiersch." Greifswald : Universitätsbibliothek Greifswald, 2017. http://d-nb.info/1148572864/34.
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Quezada, Maxwell Josias. "Hydrogénation catalytique de CO₂ en méthanol en lit fixe sous chauffage conventionnel et sous plasma à DBD ZSM-5 surface modification by plasma for catalytic activity improvement in the gas phase methanol-to-dimethylether reaction." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMIR12.
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L’objectif de cette thèse est de contribuer à l’optimisation de la production de méthanol par hydrogénation de CO₂ en synthétisant des nouveaux catalyseurs sous forme d’extrudés pour un usage industriel. Six catalyseurs à base de Cu et ZnO supportés sur de l’alumine et des ZSM-5 ont été préparés et testés. A 36 bar et sous chauffage conventionnel, le CuZnO/Al₂O₃ a montré le meilleur rendement en méthanol. Un procédé industriel basé sur ce catalyseur a été proposé et optimisé. L’influence de l’extraction de l’eau et du méthanol du milieu réactionnel en utilisant deux réacteurs en série au lieu d’un a été étudié et il a été trouvé que cela augmente le rendement en méthanol considérablement. Sous plasma à DBD et à 1 bar, le Cu/Al₂O₃ donne des meilleures conversions de CO₂, alors que le CuZnO/ZSM-5 montre des meilleurs rendements en méthanol. Cela a été attribuée à la conductivité ionique et à la constante diélectrique des matériauxThe objective of this thesis is to contribute to the optimisation of the production of methanol by hydrogenation of CO₂ by synthesising new catalysts in the form of extrudates for industrial use. In this regard, six Cu-ZnO based catalysts supported on alumina and ZSM-5 were prepared and tested. At 36 bar and under conventional heating, the CuZnO/Al₂O₃ showed the best methanol yield. An industrial process based on this catalyst has been proposed and optimised. The influence of extracting water and methanol from the reaction medium using two reactors in series instead of one was investigated and it was found to increase methanol yield considerably. Tests at atmospheric pressure and under DBD plasma showed that the Cu/Al₂O₃ gives better CO₂ conversions, while the CuZnO/ZSM-5 showed better methanol yields. This was attributed to the ionic conductivity and the dielectric constant of the catalysts
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Zhu, Yifei. "Numerical Study of Nanosecond Capillary and Surface Dielectric Barrier Discharges : Kinetics, Transport and Fluid Responses." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX027/document.
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Les décharges pulsées nanoseconde sont caractérisées par un fort champ réduit (centaine Td) et une forte thermodynamique hors-équilibre. Ils ont de l’énergie électronique de quelques eV à quelques dizaine eV et la déposition d’énergie spécifique de 10^-3 eV/mol à quelques eV/mol.Deux configurations particulières sont étudiées: (i) décharge capillaire nanoseconde (nCD) fonctionnant à la pression modérée et à une haute, et (ii) décharge contrôlée par barrière diélectrique surfacique de nanoseconde, fonctionnant à la pression atmosphérique ou à la pression plus élevée, et à une énergie spécifique de la déposition relativement faible.La décharge capillaire nanoseconde est un outil expérimental pour analyser le nanoseconde plasma dans certaines conditions extrêmes. Des expériences récentes de nCD ont révélé que la cinétique du plasma change considérablement quand l’énergie spécifique de la déposition est plus élevée. L'un des objectifs du travail est d'étudier numériquement les effets de la cinétique modifiée sur la technique classique de la mesure de l’actinométrie, et sur l’évolution spatial-temporelle du plasma dans la décharge et en post-décharge.La décharge contrôlée par barrière diélectrique surfacique de nanoseconde a été largement étudiée dans la communauté de l'aérodynamique. Cependant, au début de démarrer le travail, les paramètres de nSDBD n'étaient pas bien compris, la comparaison des calculs numériques et des résultats expérimentaux n'étaient pas disponibles. Par conséquent, la modélisation de nSDBD et la comparaison avec des résultats expérimentaux sous les mêmes paramètres est un autre objet de la thèse.Le travail dans ce manuscrit est organisé en trois parties. Dans la première partie, la modélisation numérique et les expérimentations de l’actinométrie basée sur l’Ar sont utilisées pour étudier la densité de l’oxygène atomique dans une décharge capillaire nanoseconde. Un schéma cinétique décrivant le comportement cohérent de l'ensemble des données expérimentales est développé. Les processus principaux, qui sont responsables de la population et de la décroissance des trois espèces intéressés sont sélectionnés à base de l’analyse de la sensibilité et du taux. Le rôle des réactions entre les espèces excitées et les électrons a l’entrée de la post-décharge pour une décharge pulsée au grand champ électrique et haute énergie spécifique de la déposition est discuté.La deuxième partie est consacrée à étudier, analyser et prévoir des caractéristiques de la décharge et de la post-décharge de nCD sous différents énergie spécifique de la déposition , basées sur un code auto - cohérent bidimensionnel, nonPDPsim. La propagation de la décharge a été modélisée. Deux modes de propagation ont été identifiés, trois formes d'ondes d'ionisation sont trouvées en variant le rayon de tube. Le taux de décroissance et la distribution radiale des électrons et de N2(C3) dans la post-décharge sont étudiés en respectant l’énergie spécifique de la déposition.Finalement, un modèle parallèle bidimensionnel PASSKEy («PArallel Streamer Solver with KinEtics») a été développé et validé pour modéliser le nSDBD. Une série de calculs numériques pour un seul pulse de nSDBD dans l'air à la pression atmosphérique à une amplitude de tension de 24 kV a été effectuée, les résultats ont été comparés avec des résultats expérimentaux dans les mêmes conditions. Vitesse calculée et mesurée De l’entrée de la décharge, courant électrique, carte plan 2D d'émission de N2(C3)->N2(B3), et perturbations hydrodynamiques provoquées par la décharge sur l'échelle de temps sont analysées de 0, 2 à 5us. L'effet de différents processus cinétiques dans la distribution 2D de la chaleur est étudié. Les données sont présentées et analysées pour la polarité de tension négative et positive. Un ensemble de calculs paramétriques avec différentes permittivité diélectrique, différent épaisseur des diélectriques et différente pression ambiantes sont présentésNanosecond pulsed discharges are characterized by high reduced electric fields (hundreds of Td) and strong nonequilibrium. They have characteristic electron energies of a few to tens of eV and specific energy deposition ranging from 10$^{-3}$ eV/mol to a few eV/mol. The energetic electrons can efficiently generate chemical active species, lead to fast gas heating. These discharges are found in a growing list of successful practical applications: gas pollution control, surface treatment, plasma assisted aerodynamics, plasma assisted biology and medicine and plasma assisted combustion.Two particular configurations are studied in present work: (i) nanosecond capillary discharge (nCD) operated at moderate pressures and high specific deposited energy, and (ii) nanosecond surface dielectric barrier discharge (nSDBD) operated at atmospheric or higher pressures and relatively low specific deposited energy.Nanosecond capillary discharge is an experimental tool to analyse nanosecond plasma in some limit extreme conditions. Recent nCD experiments revealed that, plasma kinetics changes dramatically at high specific energy deposition. One of the aims of the present work, is to study numerically the effects of the changed kinetics to the classical actinometry measurement technique, and the spatial-temporal evolution of plasmas during discharge and afterglow.Nanosecond surface dielectric barrier discharge has been widely studied in the community of aerodynamics. However, at the moment of starting the thesis, the parameters of nSDBD plasma were not yet clearly understood, detailed comparison of numerical calculations and experiments were not available. Therefore, modelling of nSDBD and comparison with experiments performed for the same parameters is another object of the presented thesis.The results in the thesis are presented in three parts. In the first part, numerical modelling and experiment of Ar-based actinometry are used to study the atomic oxygen density in nanosecond capillary discharge. A kinetic scheme describing consistent behavior of the set of the experimental data is developed. The main processes responsible for population and decay of the three species of interest are selected on the basis of sensitivity and rate analysis. The role of the reactions between excited species and electrons in early afterglow for pulsed discharges at high electric fields and high values of specific deposited energy is discussed. Density of O-atoms in the ground state is obtained from the calculations.The second part is devoted to study, analyse and predict the features of the discharge and afterglow of nCD under different specific energy deposition based on a two--dimensional self-consistent code, nonPDPsim. Propagation of the discharge have been modelled. Two modes of propagation were identified, three shapes of ionization waves are found with various tube radius. The decay rate and radial distribution of electrons and $rm N_2(C^3Pi_u)$ in the afterglow are studied with respect to specific energy deposition.Finally, a two--dimensional parallel PASSKEy (``PArallel Streamer Solver with KinEtics'') code coupling plasma and hydrodynamics has been developed and validated to model nSDBD. Series of numerical calculations for a single pulse nSDBD in atmospheric pressure air at 24~kV voltage amplitude has been performed, the results were compared with experiments in the same conditions. Calculated and measured velocity of the discharge front, electrical current, 2D map of emission of N$_2$(C$^3Pi_u$) $rightarrow$ N$_2$(B$^3Pi_g$), and hydrodynamic perturbations caused by the discharge on the time scale $0.2-5$~$mu$s are analysed. The effect of different kinetics processes in 2D distribution of heat release is studied. The data are presented and analyzed for negative and positive polarity of voltages. A set of parametric calculations with different dielectric permittivity, the thickness of dielectric and ambient pressures are presented
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Klute, Felix David [Verfasser], Joachim [Akademischer Betreuer] Franzke, and Manfred [Gutachter] Bayer. "Characterization of dielectric barrier discharges for analytical applications / Felix David Klute ; Gutachter: Manfred Bayer ; Betreuer: Joachim Franzke." Dortmund : Universitätsbibliothek Dortmund, 2019. http://d-nb.info/1205156801/34.
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Vandenabeele, Cédric. "Étude des mécanismes d'adhésion entre une gomme caoutchouc et un fil métallique revêtu d'une couche mince déposée par plasma." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0047/document.
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L'objectif de cette thèse est de développer un procédé plasma qui puisse se substituer au procédé de dépôt électrolytique de laiton, actuellement appliqué sur les fils d'acier utilisés comme matériaux de renforcement dans un pneu, pour les faire adhérer au caoutchouc. La stratégie employée consiste à déposer une couche mince organochlorée en continu sur un fil d'acier zingué, qui traverse une décharge à barrière diélectrique tubulaire, fonctionnant à la pression atmosphérique, dans une configuration fil-cylindre. Dans un premier temps, les travaux se concentrent sur la caractérisation de la décharge et de la couche mince déposée à la fois en mode statique (substrat immobile dans le réacteur) et dynamique (substrat en défilement). Des relations sont établies entre les paramètres plasma (puissance dissipée dans la décharge, fréquence de la source haute tension, flux de précurseur), les propriétés de la décharge et les caractéristiques du revêtement plasma. Des études morphologique, cinétique et chimique de la couche mince sont réalisées. Dans un second temps, la préparation de la surface du substrat et le dépôt plasma sont optimisés pour permettre d'obtenir les meilleurs niveaux d'adhésion entre l'acier zingué et le caoutchouc. À l'issue de ce travail d'optimisation, des analyses sont réalisées pour identifier la nature de la nouvelle interphase d'adhésion. Cette étude se conclut alors par une discussion sur l'origine possible des liens qui s'opèrent dans ce nouveau systèmeThe primary objective of this thesis project is to develop a plasma process able to replace the electrolytic brass plating process, which is currently performed on steel wires used as reinforcing materials in tires to make them bond with rubber. The chosen strategy consists in depositing organo-chlorinated thin films in a continuous way on zinc-plated steel wires going across a tubular atmospheric pressure dielectric barrier discharge in a wire-cylinder configuration. In a first time, works focus on characterization of both the discharge and the plasma layer, deposited in the static (substrate stationary in the reactor) and dynamic (moving substrate) modes. Relationships are established between the plasma parameters (power dissipated in the discharge, high voltage source frequency, precursor flow rate), the discharge properties and the thin film characteristics. Morphological, kinetic and chemical studies of the plasma layer are carried out. In a second time, the substrate surface preparation and the coating are optimized to enhance the adhesion between zinc-plated steel wires and rubber. Analyses are performed to identify the new adhesion interface nature. At the end of this study, hypotheses concerning the adhesion origin in this system are formulated
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Halethimmanahally, Thejaswini C. [Verfasser]. "Atmospheric-Pressure Dielectric Barrier Discharges: Synthesis and Deposition of Organic plasma polymers and their characterizations / Thejaswini C. Halethimmanahally." Greifswald : Universitätsbibliothek Greifswald, 2012. http://d-nb.info/1028455658/34.
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Ito, Yosuke. "Studies on Microplasmas in Coaxial Dielectric Barrier Discharges and Their Application to Thin Film Deposition at Atmospheric Pressure." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120872.
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Alberghi, Ciro. "Trattamento di cellule cancerose mediante plasmi non termici." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11524/.
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Con lo sviluppo di sorgenti capaci di sostenere scariche di non equilibrio a pressione atmosferica è nato un notevole interesse per le applicazioni biomediche del plasma, data la generazione nella scarica di una varietà di agenti efficaci in più ambiti.
I plasmi di questo tipo, caratterizzati principalmente da una temperatura macroscopica vicina a quella ambiente, sono infatti già utilizzati, ad esempio, per la sterilizzazione, per il trattamento di polimeri per migliorarne la biocompatibilità, e per l’accelerazione del processo di coagulazione del sangue.
In questo lavoro verrà presentata un’altra possibilità applicativa, sempre nel settore della plasma medicine, ovvero l’utilizzo dei plasmi per il trattamento di cellule cancerose, che sta avendo un particolare successo a causa dei risultati ottenuti dai vari gruppi di ricerca che sottintendono un suo possibile futuro nel trattamento di neoplasie.
Verrà presentata una breve introduzione alla fisica del plasma, mostrando alcuni parametri che caratterizzano questo stato della materia, concentrandosi in particolare sui plasmi non termici o di non equilibrio, per poi passare al processo di ionizzazione del gas.
Nel secondo capitolo sono approfondite due sorgenti per la generazione di plasmi non termici, la scarica a barriera dielettrica e il plasma jet.
Il terzo capitolo fornisce una preliminare spiegazione degli agenti generati nella scarica e il rapporto che hanno con la materia con cui interagiscono.
L’ultimo capitolo è il fulcro della ricerca, e comprende risultati ottenuti negli ultimi anni da vari gruppi di ricerca di molte nazionalità, e una breve parte riguardante la sperimentazione originale svolta anche in mia presenza dal gruppo di ricerca del Dipartimento di Ingegneria dell’Energia Elettrica e dell’Informazione “Guglielmo Marconi”, rappresentato principalmente dal professor Carlo Angelo Borghi e dal professor Gabriele Neretti.
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Meißer, Michael [Verfasser]. "Resonant Behaviour of Pulse Generators for the Efficient Drive of Optical Radiation Sources Based on Dielectric Barrier Discharges / Michael Meißer." Karlsruhe : KIT Scientific Publishing, 2013. http://www.ksp.kit.edu.
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Balcon, Nicolas, and nicolas balcon@gmail com. "Atmospheric pressure Radio Frequency discharges, diagnostic and numerical modeling." The Australian National University. Research School of Physical Sciences and Engineering, 2008. http://thesis.anu.edu.au./public/adt-ANU20080318.234936.
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The aim of this thesis is to investigate the properties of a Radio Frequency capacitive discharge at atmospheric pressure in argon. In these conditions where the pressure x distance product is around 150 Torr.cm, the discharge usually consists of several locally hot filaments. By pulsing the RF generator with an appropriate width and period, it was found possible to control the filament to glow transition in order to obtain a diffused and stable plasma.¶
The 2 mm gap between the electrodes is open to the ambient air and fed with argon via one hundred submillimetric holes regularly spread on the surface of the top electrode. This configuration allows on-line surface treatment of polymer films without having to turn the discharge off between successive samples. An important and lasting improvement of the polymer wettability is quickly obtained without risk of damage.
The plasma diagnostic methods are emission spectroscopy and electric measurements. The Stark broadening of the Balmer β transition line of atomic hydrogen is measured to determine a plasma density of 10^15/cm3 in the filamentary mode. The glow mode density estimation was based on power balance yielding a density of 5×10^11/cm3. Emission line ratios between neutrals and Ar+ ions are used in the Saha equation to calculate the electron temperature. It results in an approximation of 1.3 eV for the glow mode and 1.7 eV for the filaments.¶
A unidimensional self-consistent fluid model is developed to gain insight into the homogeneous discharge behaviour. Poissons equation for the electric field is coupled to the first moments of the Boltzmann equation (continuity equation, drift-diffusion equation and energy equation). Transport and reaction coefficients are obtained from the mean energy of the electrons.¶
The model is applied to a reduced argon kinetic with the main ionization and excitation processes. Simulation results are in agreement with experimental measurements. The atmospheric pressure RF discharge is similar to a lower pressure RF discharge for which the ionization occurs mainly inside the oscillating sheaths where electrons are the most energetic
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Sheehe, Suzanne Marie Lanier. "Heat Release Studies by pure Rotational Coherent Anti-Stokes Raman Scattering Spectroscopy in Plasma Assisted Combustion Systems excited by nanosecond Discharges." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1401377491.
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Affonso, Nobrega Pedro Henrique. "Conception et mise au point d’un réacteur plasma innovant pour le traitement de composés organiques volatils en milieu industriel." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM042/document.
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Des composés organiques volatils (COV) présents dans l'air peuvent avoir un fort impact odorant et doivent être traités. Des techniques de traitement classiques permettent de récupérer ou détruire ces composés. Cependant, ces techniques ne sont pas adaptées aux forts débits d'air et/ou aux faibles concentrations, caractéristiques de certains procédés industriels émetteurs de COV. Une alternative prometteuse est l'utilisation de plasmas non-thermiques. Ce type de plasma, obtenu par des décharges électriques hors-équilibre thermodynamique, contient des espèces réactives qui provoquent la destruction des composés organiques volatils. Cette thèse vise à concevoir, construire et tester un réacteur basé sur des plasmas non-thermiques pour le traitement de COV à l'échelle pilote, afin de démontrer la faisabilité d'un tel procédé pour le traitement d'odeurs présentes dans un effluent industriel. Les résultats obtenus montrent que, couplé à un catalyseur, le traitement d'odeurs par plasma non-thermique a un vrai potentiel d'application à l'échelle industrielle. En parallèle, cette thèse cherche à mieux comprendre le rôle des transferts de masse au sein d'un réacteur à l'aide d'un modèle analytique et de simulations numériques. Nous montrons que ces transferts peuvent devenir le processus limitant dans le traitement, et demandent donc une attention particulière lors du design d'un réacteur basé sur des plasmas non-thermiquesVolatile organic compounds (VOC) present in the atmosphere may have a strong odour impact and, being so, must be treated. Some long-established treatment techniques may be able to recover or destruct these compounds. However, these techniques are not suitable for high flow rates and/or low concentrations, typical conditions found in certain VOC-emitting industrial processes. A promising alternative is the use of non-thermal plasmas. This kind of plasma, obtained through non-equilibrium electric discharges, produce reactive species that prompt the destruction of volatile organic compounds. This thesis aims to conceive, build and test a reactor based on non-thermal plasmas for the abatement of volatile organic compounds at pilot scale, in order to demonstrate the feasability of using such a process to treat odourous compounds present in an industrial effluent. The obtained results show that, combined with a catalyst, the use of non-thermal plasmas for odour control in industrial scale has a real potential. In parallel, this thesis seeks a better understanding of the role played by mass transfer in a non-thermal plasma reactor through the use of an analytical model and numerical simulations. We show that mass transfer may become the limiting process of the treatment, and therefore requires special care throughout the design of a non-thermal plasma reactor
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Martin, Virginie. "Etude de microdécharges comme source de rayonnement ultraviolet intense." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00656909.
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La décontamination bactériologique des surfaces par lumière pulsée est un enjeu de société qui requiert le développement de nouveaux outils. Une technique ayant prouvée son efficacité est l'utilisation de lumière pulsée dans le domaine de longueur d'onde 200-280 nm (bande d'absorption de l'ADN). Dans ce travail, nous avons étudié deux sources, Décharge à Barrière Diélectrique (DBD) et réseaux de microdécharges permettant de générer un rayonnement à 222 nm correspondant à l'émission de l'exciplexe KrCl*. Nos études ont permis de démontrer qu'il était possible de produire des décharges dans de nombreuses microcavités fonctionnant en parallèle sans aucun ballast résistif à condition d'employer une excitation impulsionnelle nanoseconde. Des études d'imagerie et de spectroscopie résolues temporellement ont démontré que l'ensemble des microdécharges s'initiaient en moins de 5 ns, ce qui permet d'envisager la réalisation de matrice de microdécharges rayonnant des puissances crêtes élevées. Dans le cas des DBD, les études ont couplé modèle et expérience, ce qui nous a permis de déterminer les étapes clés de la cinétique réactionnelle et de prédire les meilleures conditions de production d'un rayonnement intense à 222 nm. Par ailleurs, grâce aux microdécharges, nous avons pu réaliser une source de rayonnement VUV permettant de sonder la densité de chlore atomique dans des réacteurs de gravure plasma par spectroscopie d'absorption résonnante.
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Debien, Antoine. "Étude électromécanique et optimisation d'actionneurs plasmas à décharge à barrièrediélectrique – Application au contrôle de décollement sur un profil d'aile de type NACA0015." Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2253/document.
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Cette thèse est effectuée dans le cadre du projet Européen "PlasmAero" dont le but est de développer et d'étudier des actionneurs plasmas, et de démontrer leur capacité à contrôler des écoulements aérodynamiques. L'actionneur plasma à Décharge à Barrière Diélectrique (DBD) de surface est un moyen innovant pour contrôler un écoulement en utilisant le vent électrique induit par la force électrohydrodynamique (EHD) générée au sein du gaz ionisé. Une première partie est dédiée à l'étude des actionneurs plasmas. L'influence de la géométrie de l'électrode active d'une DBD est précisée par des mesures électriques, optiques et mécaniques. Les régimes de la décharge de surface peuvent être totalement modifiés, tout commel'évolution de la force EHD en fonction du temps, calculée ici par bilan intégral. Une géométrie optimisée permet de supprimer le régime de décharge streamer et d'augmenter l'efficacité de l'actionneur de 0,65 à 0,97 mN/W. De plus, des configurations à multi-électrodes (sliding discharge et multi-DBD) sont étudiées et développées. Une multi-DBD à potentiels alternés a permis d'obtenir un vent électrique record de 10,5 m/s.L'étude du contrôle d'un écoulement décollé à mi-corde ou en bord de fuite sur l'extrados d'un profil NACA 0015 fait l'objet de la seconde partie de la thèse. Une DBD standard à deux électrodes, une multi-DBD à six électrodes et une DBD de type "nanoseconde" sont utilisées pour agir sur une séparation à des nombres de Reynolds atteignant 1,3μ106, avec une transition naturelle ou déclenchée. Les résultats démontrent que le contrôle permet de repousser efficacement la séparation, améliorant ainsi les performances aérodynamiques du profilThis work is conducted in the framework of the European PlasmAero project that aims to demonstrate how plasma actuators can be used to control aircraft aerodynamic. Surface Dielectric Barrier Discharge (DBD) is an innovative solution to control a flow with the electric wind induced by the electrohydrodynamic (EHD) force produced by a surface discharge. A first part is dedicated to plasma actuators study. The exposed electrode shape of a DBD actuator is investigated by electrical, optical and mechanical characterization. Discharges properties and EHD force evolution is fully dependent of exposed electrode shape. With an optimized active electrode shape, streamer discharge is cancelled while actuator effectiveness is increased from 0.65 to 0.97 mN/W. Flow field induced by multiple electrode design is also investigated. An innovative multi-DBD design is proposed. Inhibition of mutual interaction between successive DBD actuators and exposed electrode shape optimization conduct to an electric wind velocity of 10.5 m/s. In a second part, the control of boundary layer separation on a NACA 0015 airfoil is investigated. An ac DBD, a multi-DBD and a nanosecond DBD are used to manipulate separation at a Reynolds number Re = 1.3μ106, with tripped and natural boundary layer. Results show that actuators can effectively remove the separation existing without actuation
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Girard, 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.
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Les plasmas froids sont des gaz partiellement ionisés, très riches d’un point de vue physico-chimique. Cette propriété se retrouve dans des plasmas froids aujourd’hui générés à pression atmosphérique et température ambiante et a été mise à profit depuis une quinzaine d’années environ pour des applications biomédicales (hématologie, dermatologie, cancérologie, odontologie etc…). L’efficacité de ces plasmas froids dans le domaine de la médecine a été prouvée par de nombreuses études. Cependant, les phénomènes biologiques mis en jeu ne sont pas encore bien compris, et il primordial de savoir quels pourraient être les éventuels effets secondaires indésirables de ces milieux ionisés réactifs. Le premier niveau d’interaction des plasmas avec le vivant est celui avec les milieux liquides, qui sont présents en surface des tissus, des cellules in vivo ou en culture. Depuis une décennie, une attention particulière a donc été portée aux interactions des plasmas avec les liquides, pour apporter un niveau de compréhension supplémentaire. La compréhension de ces interactions a constitué l’axe de ce travail. Différents réacteurs à plasmas froids (générés à pression atmosphérique et température ambiante) ont été développés, notamment afin de contrôler les interactions du plasma avec l’air ambiant qui peuvent être problématiques pour les applications visées. La nature du gaz servant à initier le plasma a été modifiée, pour connaître son influence sur la réactivité chimique de la phase gaz. Pour cela, des mesures de spectroscopie d’émission optique (SEO) ont été nécessaires. Par ailleurs, de nouveaux capteurs électrochimiques et des approches méthodologiques ont été développés pour identifier et quantifier les espèces réactives de l’oxygène et de l’azote (RONS) produites dans des milieux liquides physiologiques, exposés à ces gaz ionisés. Les analyses électrochimiques ont été combinées à de la spectroscopie d’absorption UV-visible ainsi qu’à d’autres méthodes de chimie (pH-métrie/conductimétrie). Un des objectifs visés est d’établir une corrélation entre les espèces réactives générées dans la phase gaz et dans la phase liquide. Enfin, des expérimentations nous ont permis d’analyser la production des RONS dans des liquides in situ en temps réel. Les mesures de SEO montrent qu’il existe de nombreuses espèces chimiques excitées au sein des différents plasmas (NO°, HO°, O, N2+ (FNS) etc…). Les analyses de la phase liquide ont révélé la présence d’espèces stables de l’oxygène et de l’azote (H2O2, NO2-, NO3-), directement reliées aux espèces détectées dans les plasmas. De plus, les diverses méthodologies d’analyse chimique mises en place ont permis la détection et la quantification de RONS tels que l’anion peroxynitrite ONOO-. L’ensemble des résultats obtenus devrait permettre d’appréhender de façon plus fine les effets induits par différents plasmas froids dans des milieux liquides physiologiques afin d’établir un lien avec les études menées sur des cellules en culture et sur la peau dans le cadre d’un programme de recherche financé par l’ANR, Agence Nationale de la rechercheCold 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
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(5930600), Aarthi Devarajan. "Development of plasma actuators for high-speed flow control based on nanosecond repetitively pulsed dielectric barrier discharges." Thesis, 2019.
Find full textAbstract:
Over the past few decades, surface dielectric barrier discharge (SDBD)
actuators have been studied extensively as aerodynamic flow control devices. There
has been extensive research on producing SDBD plasmas through excitation by
sinusoidal high voltage in low-speed flows, resulting in local acceleration of
the flow through the electrohydrodynamic (EHD) effect. However, high-speed flow
control using SDBD actuators has not been considered to the same extent.
Control through thermal perturbations appears more promising than using EHD
effects. SDBDs driven by nanosecond repetitively pulsed (NRP) discharges (NRP SDBDs)
can produce rapid localized heating and have been used to produce better flow
reattachment in high-speed flows. While surface actuators based on NRP DBDs
appear promising for high-speed flow control, the physics underlying the
plasma/flow coupling are not well understood and the actuators have yet to be
fully characterized or optimized. In
particular, methods for tailoring the plasma characteristics by varying the
actuator’s electrical or geometrical characteristics have not been thoroughly
explored.In the current work, NRP SDBD
actuators for control of high-speed flows are developed and characterized. As
discussed previously, it is believed that the mechanism for high-speed flow
control by these plasmas is thermal perturbations from rapid localized heating.
Therefore, the goal is to design actuators that produce well-defined
filamentary discharges which provide controlled local heating. The electrical
parameters (pulse duration, PRF, and polarity) and electrode geometries are
varied and the optimal configurations for producing such plasma filaments over
a range of ambient pressures are identified. In particular, single and double
sawtooth shaped electrodes are investigated since the enhanced electric field
at the electrode tips may permit easier production of “strong” (i.e. higher
temperature) filaments with well-defined spacing, even at low pressure.
Time-resolved measurements of the gas temperature in the plasma will be
obtained using optical emission spectroscopy (OES) to assess the thermal
perturbations produced by the actuators. To the author’s knowledge, these will
be the first such measurements of temperature perturbations induced by NRP
SDBDs. The plasma structure and temperature measurements will be correlated
with schlieren visualization of the shock waves and localized flow field
induced by the discharges. Finally, the optimized actuators will be integrated
into a high-speed flat plate boundary layer and preliminary assessment of the
effect of the plasma on the boundary layer will be conducted.
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Chang, Chun-Cheng, and 張君正. "Removal of Volatile Organic Compounds(VOCs) Via Dielectric Barrier Discharge (DBD)." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/12641377168517776212.
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(11214666), Lee E. Organski. "SURFACE MODIFICATION OF INNER WALLS OF POLYETHYLENE TUBING GENERATED BY DIELECTRIC BARRIER DISCHARGE PLASMAS." Thesis, 2021.
Find full textAbstract:
Plasma treatment of polymers has been a rapidly growing area of research due to its broad applications, homogenous and repeatable surface properties, low cost, and environmental friendliness when compared to alternative techniques. Only recently have significant developments been made in the application of atmospheric pressure plasma in polymer surface treatment. The use of atmospheric pressure plasma enables further reductions in cost and mechanical complexity. Of particular interest in this work is the application of atmospheric pressure plasma for the isolated modification of the inner surfaces of small diameter polymer tubing to improve the wetting and adhesion characteristics compared to untreated polymer.
This work focuses on the development, characterization, and implementation of an atmospheric pressure dielectric barrier discharge (DBD) plasma apparatus for the treatment of the inner surface of polymer tubes. The iterative process of the development of this system is detailed, with two finalized designs established and defined. These two designs are then applied to low density polyethylene (LDPE) tubing of 0.38 mm inner diameter (ID), and characteristics for surface morphology and wettability are analyzed.
Investigation of the relationship between plasma power and treatment time with morphology characteristics of protrusion density and size and surface roughness parameter, R_a is presented. Treatment times of 5, 10, 15, 30 and 45 minutes are performed on tubing samples at a power level of 35 mW. From 5 to 15 minutes, protusion density increases rapidly, from n_p=4*10^4- 10^7 protrusions/(mm^2 ), and small variation in protrusion size, with 0.1< A_p<0.2 μm^2. At treatment times of 30 and 45 minutes, coalescence of protrusions was observed, resulting in a decrease in protrusion density, down to n≈4*10^4 protrusions/(mm^2 ), and substantial increases in mean protrusion size, up to A_P=5-9 μm^2. Plasma powers of 9, 12, 16, 25, 35, and 45 mW were also investigated, at a treatment time of 15 minutes. As power level was increased, protrusion density was observed to increase, with an inverse relationship with mean protrusion size. Protrusion density was observed to increase from n_p=2*10^5-10^7 protrusions/(mm^2 ), with diminishing increases in density observed between power levels of 35 and 45 mW. Protrusion mean size was observed to decrease from A_p= .25-0.025 μm^2, with similar diminishing reductions observed at 35 and 45 mW. Surface roughness, R_a, was observed to vary from .01-0.3 μm, or ISO roughness grades N1 to N5, in the treated samples.
Wettability characteristics were measured and characterized relative to plasma power and linear feed rate. Wettability was measured by measurement of contact angles of the meniscus formed from water introduced into the tubing volume by capillary action. On all samples treated, a duality of mechanisms for surface wetting were observed. After initial treatment, samples were observed to have a lower contact angle, indicating higher wettability, but after 12 hours samples were observed to have reduced wetting characteristics, indicating a transient mechanism for surface wetting in addition to permanent effects induced my surface morphology. Samples were treated at plasma powers of 7, 10, 15, 20, and 40 mW. At all power levels, initial contact angle was generally consistent, with 20^o< θ_0<30^o. Permanent wetting features measured on these samples indicated almost complete reversing of wettability at 7 and 10 mW, with θ_SS measured at ~75^o, comparable to the average measurement of an untreated sample of ~80^o. Conversely, at higher powers of 15, 20 and 40 mW, significant retention of wettability was observed, with 45^o<θ_SS<55^o for those samples.
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Panneerselvam, Rajbarath. "Utilization of double dielectric barrier discharge (DBD) plasma reactor in the destruction of Escherichia coli and Bacillus subtilis." 2004. http://digital.library.okstate.edu/etd/umi-okstate-1217.pdf.
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Deng, Tseng Tian, and 曾添丁. "Preliminary Study of Removing Inorganic Odors─ Hyrogn Sulfide 、 Ammonia from Gas Streams with Dielectric Barrier Discharge (DBD) Technology." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/19427421939869298013.
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Tsai, Tsung-Chan 1982. "Plasma Enhanced Chemical Vapor Deposition on Living Substrates: Development, Characterization, and Biological Applications." Thesis, 2012. http://hdl.handle.net/1969.1/148233.
Full textAbstract:
This dissertation proposed the idea of “plasma-enhanced chemical vapor deposition on living substrates (PECVD on living substrates)” to bridge the gap between the thin film deposition technology and the biological and living substrates. This study focuses on the establishment of the knowledge and techniques necessary to perform “PECVD on living substrates” and contains three main aspects: development, characterization, and biological applications.
First, a PECVD tool which can operate in ambient air and at low temperature was developed using a helium dielectric barrier discharge jet (DBD jet). It was demonstrated that various materials, such as polymeric, metallic, and composite films, can be readily synthesized through this technique. Second, the PMMA and copper films deposited using DBD jets were characterized. High-rate (22 nm/s), low-temperature (39 ºC) PMMA deposition was achieved and the film surface morphology can be tailored by altering the discharge power. Conductive copper films with an electrical resistivity lower than 1×10-7 ohm-m were obtained through hydrogen reduction. Both PMMA and copper films can be grown on temperature-sensitive substrates, such as plastics, pork skin, and even fingernail. The electrical, optical, and imaging characterization of the DBD jets was also conducted and several new findings were reported. Multiple short-duration current pulses instead of only one broad pulse per half voltage cycle were observed when a dielectric substrate was employed. Each short-duration current pulse is induced by a leading ionization wave followed by the formation of a plasma channel. Precursor addition further changed the temporal sequence of the pulses. An increase in the power led to a mode change from a diffuse DBD jet to a concentrated one. This mode change showed significant dependence on the precursor type, tube size, and electrode configuration. These findings regarding the discharge characteristics can thus facilitate the development of DBD-jet operation strategies to improve the deposition efficacy. Finally, this technique was used to grow PMMA films onto agar to demonstrate one of its potential biological applications: sterile bandage deposition. The DBD jet with the film depositing ability enabled the surface to be not only efficiently sanitized but also protected by a coating from being reached by bacteria.
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Juhászová, Lucie. "Mechanismus atomizace vybraných hydridotvorných prvků ve vyhřívaném křemenném atomizátoru a plazmovém atomizátoru s dielektrickou bariérou." Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-397505.
Full textAbstract:
Atomization conditions for tin hydride in the planar dielectric barrier discharge (DBD) plasma atomizer were optimized with detection by atomic absorption spectrometry (AAS). The effects of apparatus arrangement such as the shape of a waveform function of the high voltage power supply source, DBD atomizer design as well as presence of a dryer tube filled with NaOH pellets to prevent residual aerosol and moisture transport into the DBD were investigated in detail. The optimal experimental setup consisted of a square wave high voltage power supply source coupled to a DBD with vapor-deposited electrodes in the presence of NaOH dryer upstream the DBD atomizer. Argon was found as the best discharge gas under a flow rate of 120 mL min-1 while the DBD optimum high voltage supply rate was 7 kV. A sensitivity of 0.05 s ng-1 Sn and a limit of detection of 1.1 ng mL-1 Sn were reached under optimized conditions. Optimization of the whole experimental setup resulted in 7-fold improvement of sensitivity compared to the original arrangement consisting of a sinusoidal source coupled to a DBD atomizer with glued electrodes in absence of the dryer. Keywords atomic absorption spectrometry, hydride generation, hydride atomization, quart tube atomizer, dielectric barrier discharge (DBD)
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Hung, Pao-chen, and 洪保鎮. "Degradation of Gaseous Dioxins with Dielectric Barrier Discharges." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/70639098823489630987.
Full textAbstract:
碩士國立中央大學
環境工程研究所
95
The characteristics, formation mechanisms and control technologies of dioxin have been studied for many years. In Taiwan, dioxin content in the ash has been regulated by Taiwan EPA since May 2007. Since activated carbon injection causes the increase of dioxin concentration in the fly ash, it is not regarded as the best available control technology. Dielectric barrier discharge (DBD) has been applied for generating O3 and degrading VOCs and PFCs in flue gas, but has not been investigated for its effectiveness in dioxin removal. This study aims to evaluate the characteristics of PCDD/F removal via DBD at elevated temperature (150oC). DBD reactor is made of the borosilicate glass tube with the inner diameter of 26.8 mm. A stainless steel rod with the diameter of 3.2 mm is used as the inner electrode and the length of discharge region is 105 mm. Experimental tests are conducted at fixed temperature (150oC), space velocity (2000 hr-1), applied voltage (12 kV) and frequency (100 Hz), while the concentrations of oxygen (O2) vary from 0 % to 21% and water vapor [H2O(g)] contents vary from 0 % to 20 %, respectively. The breakdown voltage of the DBD reactor investigated decreases from 12 kV to 8.4 kV as the temperature is increased from 300K to 473K. The maximum applied voltage is greater than 18 kV at 300K and decreases to 8.7 kV as the temperature is increased to 453K. Residual dioxin is less than 2 % of the total injected dioxin at 150oC and system can be operated over 90 minutes with the applied voltage of 12 kV. The mass and TEQ removal efficiencies of dioxin are 61.3 % and 49.9 %, respectively, with pure nitrogen as the carrier gas. As the oxygen content is increased from 5 % to 21 %, the mass removal efficiency is reduced from 44.9 % to 43.1 % and the TEQ removal efficiency decreases from 40.2 % to 36.6 %. The PCDD/Fs removal efficiency does not change significantly with the oxygen content in the gas stream. As the water vapor content is increased from 0 % to 20 %, the highest PCDD/Fs removal efficiency is achieved at 20 % (16.8 % O2) and the mass and TEQ removal efficiencies are 78.1 % and 71.4 %, respectively. On the other hand, the lowest mass removal efficiency (37.3 %) is achieved with the water vapor content of 5 % (20.0 % O2) and the lowest TEQ removal efficiency (32.1 %) is achieved with the water vapor content of 1 % (20.8 % O2). Free radicals including OH can be effectively generated in the DBD reactor if the gas stream contains H2O(g) and O2 as predicted by BOLSIG. On the other hand, free radicals generated from O2 are not effective for PCDD/F removal. Removal of dioxin is mainly achieved by electron collision in the absence of water vapor while OH radical is essential for PCDD/F removal for the gas stream containing H2O(g).
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Wu, Shi-Jia, and 吳錫佳. "Study on Ozone Synthesis via Dielectric Barrier Discharges." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/83702048939306693156.
Full textAbstract:
碩士國立中央大學
環境工程研究所
83
Dielectric barrier discharge (DBD) has been applied to generate ozone for industrial use for quite a long time. This is initiated to evaluate the effectiveness of applying DBD plasmas to generate O3 and the dependencies of O3 generation rate on operating parameters including applied voltage, gas residence time, inlet gas composition, relative humidity and power input. Experimental results indicate that ozone concentration increases with increasing applied voltage. When O2 is fed into the reactor , the ozone concentration increases up to 30 g/m3 and then levels off while the maximum ozone concentration of 20 g/m3 is reached when air is fed into the reactor. The lower O3 concentration obtained with air is possibly due to the effect of NOx poison. Ozone generation rate varies as the gas residence time and reactor type change. Maximum ozone generation rate can be obtained by Controlling the gas residence time for a given applied voltage and inlet gas composition. The reactor with single dielectric barrier results in a higher O3 generation rate compared to the reactor with double dielectric barriers. Given a constant N2/O2 in the feeding gas, NOx concentration tend to increase as applied voltage and gas residence time increases. Experimental results indicates that maximum NOx concentration in reached when the N2/ O2 of feeding gas is 4. Ozone generation rate decreases as the relative humidity and temperature of the inlet gas stream increases. As for the ozone generation efficiency, using single dielectric barrier reactor operated at 9kV with the gas residence time of 5.6 sec results in the maximum generation efficiency- 162 g/kWh.
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Chih, Cheng Huai, and 鄭懷志. "Study of a Ultraviolet Source by Dielectric Barrier Discharges." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/00478975026450058267.
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Orlov, Dmitriy M. "Modelling and simulation of single dielectric barrier discharge plasma actuators." 2006. http://etd.nd.edu/ETD-db/theses/available/etd-10062006-144203/.
Full textAbstract:
Thesis (Ph. D.)--University of Notre Dame, 2006.Thesis directed by Thomas C. Corke for the Department of Aerospace and Mechanical Engineering. "October 2006." Includes bibliographical references (leaves 184-189).
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Ynag, Shyh Chaur, and 楊士朝. "De-NOX Plasma Process with Hydrocarbon Additive via Dielectric Barrier Discharges." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/92084186606907325407.
Full textAbstract:
碩士國立中央大學
環境工程學系
86
AbstractNitrogen oxides (NOX) are not only known as primary precursors to acid deposition and urban smog, but also have adverse effects on human health, vegetation, visibility and materials. As a result, most common post combustion De-NOX processes, like SCR and SNCR, are applied for stationary emission control. However, these technologies leave some unavoidable disadvantages, such as poisoning of catalysts or narrow temperature windows. In order to improving those limitations when applying, inventing less pollution and more effective techniques has become an important issue in the research and industrial field. In this study, effective removal of NOX through generation of hydrocarbon radicals via dielectric barrier discharges (DBD) was demonstrated. A laboratory-scale experimental system was designed and constructed to evaluate the removal efficiency of NO and NOX. In addition, C2H2 and C2H4 were chosen as additive reducing agents in the DBD De-NOX process. The effects of operational parameters including applied voltage, additive concentration, gas composition, gas temperature, gas residence time, and power input on the removal efficiency of NO and NOX were investigated. Generally, experimental results indicated the removal efficiency of NO and NOX increased with applied voltage, additive concentration, gas temperature, H2O(g) content, gas residence time, and power input. As oxygen content increased, hydrocarbon radicals would be oxidized to CO2 easily. Such a phenomenon decreased the removal efficiency of NOX. When C2H2 was added to DBD process, as high as 91.2% of NO and 68.2% of NOX were removed at 140℃ for the gas stream containing [NO]/[C2H2]/[H2 O]/[O2] =500ppm：1,500ppm：3%：5%. The applied voltage was 20kV and the gas residence time was 9.4 seconds. In addition to N2 and H2O, major products found in this process included NO2, N2O, CO2, CO and CH2O2, depending on H2O(g) content of the gas stream.On the other hand, if C2H4 was used at the same conditions of applied voltage, gas temperature and gas residence time, as high as 100% of NO and 56.6% of NOX were removed for the gas stream containing [NO]/[C2H4]/[H2O]/[O2] =500ppm：2,000 ppm：3%：5%. In addition to N2 and H2O, major products found in this process included NO2, N2O, CO2, CO, CH2O2 and CH2O, depending on H2O(g) content of the gas stream.
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Huang, Wen-Chao, and 黃文超. "Deposition of Hydrogenated Amorphous Carbon Film by Atmosphere Dielectric Barrier Discharges." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/81037462897129365232.
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