M.Sc. / The understanding of the classification and origin of geological systems is facilitated by the acquisition of accurate and precise analytical data. New instrumentation is rapidly developed for the preparation and quantitative analysis of geological materials using smaller amounts of sample, with lower limits of detection and faster analysis times. The development of new methodologies is crucial for the effective utilisation of new instrumentation. This study was conceptualised because of the relationship between the Department of Geology and the Central Analytical Facility of the Faculty of Science, University of Johannesburg. There is a high demand for accurate and precise chemical data for various lithologies and the availability of high-end analytical equipment, but little practical expertise to utilise this equipment to its full potential. The study is centred round the analysis of four common sedimentary lithological groups that are routinely studied by the Department of Geology namely carbonate rocks, shales, iron ore and manganese ore. A large literature base exists for the decomposition and analysis of geological materials. The bulk of this literature is centred round more established and conventional methods of sample preparation and analysis. The use of microwave digestion instrumentation and methodologies in recent times has revolutionised sample decomposition with shorter decomposition times, smaller sample masses required for decomposition, lower loss of analytes to volatilisation and creating a safer laboratory environment for analysts to work in. Inductively coupled plasma optical emission spectroscopy (ICP-OES) is a more mature method of sample analysis, being commercialised in the mid 1970’s, while inductively coupled plasma mass spectroscopy (ICP-MS) is a newer technique, v being commercialised as of the mid 1980’s. These two techniques are multi-element techniques, with low limits of detection and fast analysis times for a plethora of analytes, over seventy elements for ICP-OES and over eighty elements for ICP-MS. Samples from all four lithological groups were successfully digested in a microwave digestion unit with varying combinations of nitric acid (HNO3), hydrochloric acid (HCl), perchloric acid (HClO4) and hydrofluoric acid (HF) and various digestion programs. Accurate and repeatable methods of analysis were developed for iron, manganese, calcium and potassium for all four lithologies with ICP-OES; aluminium was successfully determined for shale, iron and manganese ore with ICP-OES. Titanium, sodium, arsenic, barium, bismuth, chromium, copper, molybdenum, scandium, strontium and vanadium were determined for all four lithotypes with acceptable accuracy and repeatability using ICP-MS.

Le contrôle actif d’écoulement est une voie envisagée actuellement pour améliorer les caractéristiques aérodynamiques des véhicules aériens ou terrestres. La diminution de la traînée (force opposée au mouvement) est notamment visée, ce qui permettrait de baisser la consommation en énergie entraînant ainsi une réduction des émissions polluantes. Depuis une dizaine d’années, les actionneurs plasmas sont utilisés comme dispositifs de contrôle. À Orléans, ils sont basés sur l’utilisation d’une décharge à barrière diélectrique créant à sa surface un plasma qui induit un écoulement de quelques km h-1 : le vent ionique. L’actionneur plasma est caractérisé avec l’étude des différents régimes de décharge. Celui où des arcs énergétiques apparaissent est analysé. La température de surface de l’actionneur est également étudiée en fonction de plusieurs paramètres. Elle reste inférieure à 100 °C, ce qui confirme que les effets des actionneurs plasmas sur un écoulement ne sont dus qu’au vent ionique. Une caractérisation du vent ionique permet aussi de confirmer le lien entre le vent ionique et l’extension du plasma : deux phases distinctes existent, pendant lesquelles il est créé. Le contrôle de la transition d’une couche limite de Blasius est effectué sur une géométrie de type plaque plane. En fonction de la position de l’actionneur ou de la puissance consommée, le recul, le déclenchement précoce ou le cas sans effet est obtenu. Le mécanisme d’action est identifié et est lié à une excitation de l’écoulement qui devient plus ou moins sensible aux ondes de Tollmien-Schlichting. La fréquence de fonctionnement de l’actionneur apparaît comme le paramètre principal pour ce type de contrôle. Une nouvelle géométrie d’actionneur est proposée et caractérisée. La décharge conserve des propriétés identiques au cas classique et le sondage du vent ionique par un moyen de mesure 3D permet de montrer le gain en vitesse et l’existence de structures 3D susceptibles de contrôler plus efficacement un écoulement. / Active flow control is a route currently being considered to improve aerodynamic performances of vehicles (airplanes or cars). Drag reduction (force opposite to motion) is particularly concerned and provides reduction of energy consumption of vehicles what induces low exhaust gases emissions. Plasma actuators are used as control devices since a decade. In Orléans, they are based on the use of surface dielectric barrier discharge which creates plasma on its surface and induces a flow of few km h-1 : the ionic wind. The plasma actuator is characterized with the study of different discharge regimes. One in which sparks occur is analyzed. The actuator surface temperature is also studied in function of several parameters. Surface temperature remains below 100 °C what confirms effects of plasma actuators on the flow are only due to the ionic wind. Characterization of ionic wind has also confirmed the link between induced flow and plasma spread over actuator surface : two distinct phases exist where a flow is every time induced. Transition control of a Blasius boundary layer is performed on flat plate geometry. Depending on plasma actuator position or power consumption, promotion, delay or neutral case are obtained on transition location. The mechanism of action is identified and linked to an excitation of the flow that becomes more or less sensitive to Tollmien-Schlichting waves. The operating frequency also appears as the main parameter for this type of control. New actuator geometry is proposed and characterized. The discharge keeps identical properties to a classical configuration of plasma actuator. Ionic wind measurements by means of a 3D device allow us to show the gain in speed and presence of 3D structures in the induced flow topology what is more effectively to control external flows.

During sustained exercise, working muscles must be supplied with adequate kinds and amounts of exogenous fuels, and the delivery rates of oxygen and oxidizable substrates should be matched. The study of metabolite fluxes and their regulation is therefore critical to the understanding of exercise metabolism. Lactate has received renewed attention from physiologists and biochemists with the realization that it is not only an end product of glycolysis, but also an important fuel for aerobic work. As an oxidizable fuel, this substrate may provide some performance advantage over other fuels such as glucose and free fatty acids. The goals of this thesis were: 1) to determine whether endurance-adapted animals can support higher plasma lactate turnover rates than sedentary animals; and 2) to investigate the major factors involved in the regulation of plasma metabolite turnover at the whole-organism level - using lactate as a model. Lactate turnover rates were measured by bolus injection of [U-¹⁴C]lactate in skipjack tuna, Katsuwonus pelamis, and in thoroughbred racehorses, Equus caballus. In tuna, turnover rates ranged from 112 to 431 umol min⁻¹ kg⁻¹ and they were positively correlated with lactate concentration (slope = 15.1, r = 0.92). This teleost is able to support higher plasma lactate turnover rates than expected for a mammalian lower temperature, and lactate is probably an important oxidizable fuel in this species. For comparative purposes, resting turnover rates of lactate and glucose were plotted versus body mass on a log-log scale for a wide range of mammalian species. These plots were linear, and they showed the same slope as the classic body mass vs metabolic rate relationship. Thoroughbred horses are likely to have an aerobic scope of 40-fold or more. One of their main physiological adaptations to exercise is the ability to increase hematocrit by more than one and a half-fold in response to exercise. In the present study, this adjustment allowed them to reach an A-V difference in 0₂ content of more than 23 vol% during maximal exercise, a much higher value than other mammals. Their lactate turnover rate and cardiac output were measured at rest and two levels of submaximal exercise (45 and 55 V0₂ max) to investigate the relationship between cardiovascular adjustments on plasma lactate turnover rate. Cardiac output ranged from 106 to 571 ml min⁻¹ kg⁻¹, and mean lactate turnover rate from 9.3 at rest, to 75.9 umol min⁻¹ kg⁻¹ at 55% V0₂ max. In contrast with the situation found in tuna, the lactate turnover rates of thoroughbreds were not elevated compared with other mammals, showing that the metabolic adaptations of these outstanding athletes do not include the ability to sustain higher lactate fluxes than sedentary animals. In horses, the contribution of plasma lactate oxidation to V0₂ is minimal, and this substrate is not an important oxidative fuel; lipid oxidation may represent their major pathway for aerobic energy production during exercise. The ability to oxidize plasma lactate at high rates is therefore not necessarily required for the "elite" performance of endurance exercise. This study also shows that both, plasma lactate concentration and cardiac output are positively correlated with turnover rate. The correlation between cardiac output and lactate turnover rate is independent of the relationship between plasma lactate concentration and turnover rate. Plasma metabolite concentration and cardiac output can be regulators of plasma metabolite turnover rate. It is proposed that these two variables are, respectively, the fine and coarse controls for flux rate adjustments during exercise. / Science, Faculty of / Zoology, Department of / Graduate

Cette thèse, réalisée dans le cadre du projet PCP (Piles à Combustible par Procédés Plasma) est le fruit d’une collaboration de plusieurs années : Dreux Agglomération, les laboratoires GREMI et IEM, et l’industriel MHS Equipment. L’objectif de ce travail étant la fabrication par procédé plasma, d’un coeur de pile à combustible, dans un réacteur prototype préindustriel. Pour ce faire, deux études de faisabilités ont été menées en parallèle. La première étude, à l’IEM, porte sur la synthèse, par polymérisation plasma dans un réacteur pilote, de membranes polymères conductrices de protons. Deux précurseurs ont été utilisés : le styrène et l’acide trifluorométhanesulfonique. Les membranes polymères plasma se présentent sous la forme de dépôts denses, homogènes, et très adhérents à leur support en tissu carboné. Les membranes plasma sont intrinsèquement bien moins conductrices que la membrane commerciale Nafion®, néanmoins, leur niveau de conduction reste satisfaisant du fait de leur faible épaisseur. Les membranes plasmas profitent de leur densité et de leur fort taux de réticulation pour disposer une imperméabilité au méthanol beaucoup plus importante que celle du Nafion®. La stabilité thermique des membranes plasma, également évaluée, leur permet de supporter les températures de fonctionnement des piles. La seconde étude concerne l’élaboration des électrodes par pulvérisation magnétron dans le réacteur pilote au GREMI. L’utilisation d’une configuration de dépôt à une cible de platine ou de la combinaison d’une cible de platine et d’une cible de carbone, a permis de réduire la quantité de platine déposé sur le support carboné et conduit à l’optimisation de la dispersion du platine pour une meilleure efficacité catalytique. En outre, dans un contexte industriel, l’intégration de l’assemblage membrane électrode a été transférée sur un prototype linéaire combinant en une seule fois la polymérisation plasma et la pulvérisation magnétron. Des coeurs de pile ont été fabriqués et testés en banc de pile. / This work is part of PCP (Piles à Combustible par Procédés Plasma) project with the involvement of many partners: Dreux Agglomeration Community, GREMI and IEM laboratories, and the private industrial MHS Equipment. The aim of this work is the development of pre-industrial reactor prototype in order to manufacture by plasma processes all active layers of fuel cells cores i.e. the electrodes and the membrane. Two studies were conducted at the same time. The first from IEM have focused on the preparation by plasma polymerization, in a pilot reactor, of proton conducting polymer membranes. Two precursors were used: styrene and trifluoromethanesulfonic acid. The plasma membranes obtained are dense, uniform, and very adherent on carbon cloth support. The intrinsic ionic conductivity of plasma polymerized membranes is lower than the one of Nafion® membranes but their conduction ability is observed to be competitive due to their low thickness. Due to their highly cross-linked structure and density, plasma-polymerized membranes show methanol permeability much lower than Nafion® membranes ones. The thermal stability measurements have shown that plasma membranes easily support the operating temperature of fuel cells. The second study from GREMI concerns the development of catalyst or integral catalytic electrodes by magnetron sputtering in the pilot reactor. The use of a single platinum target or the combination of both platinum and carbon targets allowed to reduce the platinum content and to control the platinum concentration profile in the electrode support leading to the optimization of the platinum dispersion for a high increase of catalyst efficiency. Furthermore, in an industrial context, MEA’s integration was transferred using a linear industrial prototype which combines plasma polymerization for the membrane deposition and plasma sputtering for Pt deposition in a single device. Compact plasma MEA are produced and characterized in mono-cells.

Les jets de plasma sont largement utilisés dans l’industrie, dans les laboratoires pour des applications allant du traitement des déchets, à la découpe de pièces métalliques jusqu’aux dépôts de couches de protection. Dans la majorité de ces applications, les jets de plasma sont utilisés en régime turbulent. Ce régime est caractérisé par de fortes fluctuations panache, peu attractives dans le domaine du traitement des matériaux, car elles réduisent la répétabilité et le contrôle des processus. Des jets de plasma aux caractéristiques beaucoup plus stables peuvent être produits en réduisant le débit de gaz plasmagène. Ces jets de plasma sont appelés jets de plasma laminaire. Peu d’études ont été menées sur ce type de jet limitant le développement de ces torches. L’objectif du travail présenté dans ce mémoire est de réaliser l’étude d’un jet de plasma d’argon en régime laminaire à pression atmosphérique. Le diagnostic du jet a été réalisé par spectroscopie optique d’émission à partir de l’enregistrement des spectres atomique et moléculaire d’éléments présents dans le jet. Par ailleurs, ces résultats ont permis de montrer que le jet de plasma pompait l’air extérieur dans lequel fonctionnait la torche. En outre, les champs de vitesses du jet de plasma ont été mesurés par un tube de Pitot. Les distributions de températures et de vitesses déterminées expérimentalement ont été comparés aux résultats d’un modèle numérique. Pour finir, nous avons développé une méthode de mesure de la température du jet de plasma à partir des spectres d’émission des molécules de MgO et de CN produits respectivement à partir de la combustion de magnésium injecté dans le plasma et de la combustion de l’air. Ces molécules sont d’un grand intérêt dans les processus industriels mais aussi dans le domaine de l’aérospatial. / Plasma jets are widely employed both in industry and in laboratories for various applications such as wastetreatment, cutting or spraying protection coating. Usually, the plasma jets are employed in turbulent flowregime. This flow regime is characterised by large plasma jet fluctuations, undesirable in material processing, because they will reduce the process repeatability and controllability. A more stable plasma jet can be generated by reducing the flow rate of the plasma forming gas, and this is called a laminar plasma jet. Few studies have been published on the laminar plasma jet, which has limited the development of these torches. The aim of this thesis is to study a laminar argon plasma jet at atmospheric pressure. The plasma jet diagnostic was performed with an optical emission spectroscopy experiment. The atom and molecule spectra from the jet have been recorded. These results have shown that ambient air is entrained into the plasma jet. In addition, the plasma jet velocity fields were measured by a Pitot tube. The temperature and velocity distributions determined in the experiments were compared to the numeric model results. Finally, we have developed a method to measure the plasma jet temperature from the emission spectra of molecules of MgO and CN which are produced from the magnesium combustion injected into the plasma and the air combustion respectively. These molecules are of great interest in industrial processes but also in the field of aerospace.

Orientador: Marcelo Giannini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-27T08:07:39Z (GMT). No. of bitstreams: 1 Ruivo_MelissaAraujo_M.pdf: 7058282 bytes, checksum: ccb6c2382e6c36e7f4a50d09e21434b8 (MD5) Previous issue date: 2015 / Resumo: O plasma tem sido utilizado em diversas áreas da Odontologia como no clareamento dental, pois produz espécies reativas que contribuem para o clareamento através da clivagem das cadeias orgânicas dos agentes cromógenos e através da sua capacidade em aumentar a energia de superfície. Os objetivos desse estudo foram avaliar a ação do plasma associado ao peróxido de hidrogênio na alteração de cor, concentração de cálcio e fósforo e rugosidade de superfície do esmalte, utilizando as análises de espectrofotometria de reflectância, espectroscopia dispersiva por raio-X (EDX) e microscopia confocal. Foram utilizadas as porções coronárias vestibulares de dentes bovinos, os quais foram manchados com solução de chá preto e posteriormente divididos em cinco grupos: grupo PH3 (3 aplicações de peróxido de hidrogênio 38% por 15 minutos), grupo PL1+PH1 (1 aplicação de plasma por 1 minuto + 1 aplicação de peróxido de hidrogênio 38%), grupo PL1+PH3 (3 aplicações de plasma por 1 minuto + 3 aplicações de peróxido de hidrogênio 38%), grupo PL2+PH1 (1 aplicação de plasma por 2 minutos + 1 aplicação de peróxido de hidrogênio 38%), grupo PL2+PH3 (3 aplicações de plasma por 2 minutos + 3 aplicações de peróxido de hidrogênio 38%). Os dentes foram submetidos a duas sessões de clareamento, e na parte do estudo sobre a alteração de cor, as análises foram feitas após cada sessão de clareamento. Nas análises de EDX e rugosidade, a leitura foi feita apenas após a segunda sessão de clareamento. Além disso, para as análises de EDX e rugosidade foi introduzido um grupo controle que não recebeu o tratamento clareador, nem o plasma. Foram realizadas quatro tomadas de cores (análise dos parâmetros "L*", "a*", "b*" e "?E"): inicial (sem tratamento), após o manchamento e após a primeira e segunda sessões de clareamento. Os dados dos parâmetros "L*" e "b*" foram analisados por meio de análise de variância (ANOVA 2 fatores) e teste de Tukey¿Kramer (?=0,05) e para o parâmetro "a*", foram realizados testes não-paramétricos (Kruskal Wallis, Dunn e Friedman). Para a análise da concentração de cálcio e fósforo e rugosidade de superfície, os dados foram submetidos à análise de variância (1 fator) e teste de Tukey (5%). Os grupos PH3, PL1+PH3 e PL2+PH3 não diferiram entre si na análise de "b*" e "?E". Nas avaliação de "L*", "a*" e "b*" houve diferença significativa após a segunda sessão de clareamento em todos os grupos. Apenas o grupo PH3 apresentou redução da concentração de cálcio e fósforo comparado ao grupo controle (sem clareamento) e todos os grupos tratados com clareamento apresentaram aumento da rugosidade em relação ao grupo controle na análise da rugosidade (remover). Os grupos que receberam os maiores tempos de aplicação de plasma e peróxido de hidrogênio (PL1+PH3 e PL2+PH3) tenderam produzir melhores efeitos clareadores, comparados aos grupos que receberam apenas uma aplicação, como pode ser observado nas análises do parâmetro "b*" e do ?E. O uso do plasma manteve a concentração de cálcio e fósforo. Todos os grupos que envolveram clareamento, com ou sem aplicação do plasma, promoveram aumento da rugosidade de superfície do esmalte / Abstract: Plasma has been used in several areas of Dentistry even for tooth whitening, because produces reactive species that contribute to tooth whitening by cleavage of the organic chains of chromogens and the increasing of energy surface. The aims of this study were to evaluate the effect of hydrogen peroxide combined with argon plasma on color change, calcium and phosphorus concentration, surface roughness and enamel surface morphology, using reflectance spectrophotometry analysis, dispersive X-ray spectroscopy (EDX) and confocal microscopy. Vestibular coronal portions of bovine teeth were used, which were stained with black tea solution and then divided into five groups: Group PH3 (3 applications of 38% hydrogen peroxide for 15 minutes), PL1+PH1 group (1 plasma application of 1 minute + one application of 38% hydrogen peroxide), PL1+PH3 group (3 plasma applications of 1 minute + three application of 38% hydrogen peroxide), PL2+PH1 group (1 plasma application of 2 minutes + one application of 38% hydrogen peroxide), PL2+PH3 group (3 plasma applications of 2 minutes + three application of 38% hydrogen peroxide). For color measurements were performed (parameter "L*", "a*", "b*" and "?E"): initial (untreated), after staining and after bleaching (first and second sessions). For chemical composition and roughness analysis, samples were only analyzed before treatment (control group) and after two bleaching sessions. Data of "L*" and "b*" color parameters were analyzed by analysis of variance (two-way ANOVA) and Tukey-Kramer test (?= 0.05), while nonparametric tests (Kruskal Wallis, Dunn e Friedman) for the parameter "a*". The concentrations of calcium and phosphorus data was analyzed by one-way ANOVA (5%). PH3, PL1+PH3 and PL2+PH3 groups did not differ for "b" and "?E" analysis. For "L*", "a*" and "b*" parameters, there was a significant difference after second bleaching session for all groups regarding the stained teeth. Only PH3 group decreased the concentration of calcium and phosphorus compared to untreated control group and all bleached groups differed significantly from control group, regarding the surface roughness. Groups that received more amount of argon plasma and hydrogen peroxide (PL1+PH3 and PL2+PH3) tended to enhance the whitening compared to the groups with only one application of hydrogen peroxide, as observed in the analysis of the parameters "b*" and ?E. The use of plasma preserves the concentration of calcium and phosphorus elements. All bleached groups, with plasma application or not promoted increasing of enamel surface roughness / Mestrado / Materiais Dentarios / Mestra em Materiais Dentários

Os aços de ultra resistência com médio carbono e baixa liga apresentam excelentes propriedades de resistência mecânica e à fadiga além de uma elevada temperabilidade. No entanto, tais aços apresentam o fenômeno da têmpera ou de tratamentos superficiais. O aço 300M foi desenvolvido visando a ampliação desta faixa, permitindo tratamentos em temperaturas em torno de 350ºC viabilizando o emprego da técnica de nitretação do mesmo por plasma sem a consequente fragilização. Neste trabalho comparou-se as características e propriedades do aço 300M nitretado por plasma à 350ºC e 550ºC com os aços de alta-resistência AISI 4340, 4140 e 5140 nitretados à 550ºC. Variou-se as condições de tratamento de forma a verificar a influência do tempo de nitretação e de frequência de pulso nas camadas nitretadas. Verificou-se que a nitretação por plasma demostrou ser bastante efetiva para conferir resistência ao desgaste abrasivo para todos os aços nitretados. O aço 300M nitretado em 350ºC apresentou no ensaio de desgaste abrasivo comportamento similar aos demais aços nitretados em 550ºC, enquanto que o melhor resultado geral foi alcançado pelo 300M nitretado à 550ºC em CC durante 6 horas, devido à formação de uma camada dupla de levada dureza e espessura. / The ultrahigh-strength steels with medium carbon and low alloy, like AISI 4340, show excellent tensile strength and fatigue properties further higher hardenability. However, these steels have the phenomenon of tempering embrittlement, that restrict the temperature of treatments after quench or surfaces treatments. The 300M steel was developed aiming the enlargement this area of application, this steel permits treatments in temperatures about 350°C what allowed to use the plasma nitriding without problems with the embrittlement. In this production were compared the properties of the nitrited layers of the 300M nitriding by plasma in 350°C and 550°C with the steels AISI 4340, AISI 4140, AISI 5140 nitriding in 550°C. Plasma nitriding conditions like time and pulse frequency were varied. It was checked that the plasma nitriding showed good performance to improve the resistance to the abrasive wear in ali the steels tested. The 300M steel nitrited in 350°C showed results similar to the others in the pin-on-disk test and the better result occurred to the 300M steel nitrited in 550°C in dC plasma during 6 hours, because of a duble compound lawyer that arouse with a high thickness and high hardness.

Orientador: Maria Filomena Rocha Lima Huhtala / Banca: César Rogério Pucci / Banca: Sérgio Eduardo de Paiva Gonçalves / Banca: Marcelo Giannini / Banca: Priscila Christiane Suzy Liporoni / Resumo: Objetivo: avaliar a influência do tratamento de superfície com plasma não térmico de argônio (PLA) na resistência de união de cimentos resinosos ao esmalte, à dentina e à cerâmica de dissilicato de lítio. Observar, no esmalte e na dentina, através de espectroscopia de infravermelho por transformada de Fourier (FTIR) os compostos inorgânicos e da cromatografia gasosa a alteração dos compostos orgânicos voláteis nas condições experimentais propostas. Material e Método: Foram avaliados 3 cimentos resinosos: Variolink Esthetic LC e N (Ivoclar Vivadent), e Panavia V5 (Kuraray). Foram utilizados 240 dentes bovinos, dos quais 150 tiveram a superfície do esmalte exposta e 90 a de dentina. Foram obtidas 150 lâminas de cerâmica de dissilicato de lítio (12 x 14 x 0,5 mm). Os grupos foram divididos de acordo com o tratamento de superfície e o substrato. Os tratamentos para as superfícies de esmalte e dentina foram: EA (esmalte/ácido fosfórico); DA (dentina/ácido fosfórico); EPS (esmalte/PLA 30 s); EPM (esmalte/PLA 1 min); DPS (dentina/PLA 30 s); EAPS (esmalte/ácido fosfórico/PLA 30 s) e EAPM (esmalte/ácido fosfórico/PLA 1 min); e, DAPS (dentina/ácido fosfórico/PLA 30 s). Os tratamentos para as superfícies da cerâmica foram: CA (cerâmica/ácido fluorídrico), CPS (cerâmica/PLA 30 s); CPM (cerâmica/PLA 1 min); CAPS (cerâmica/ácido fluorídrico/PLA 30 s) e CAPM (cerâmica/ácido fluorídrico/PLA 1 min). Posterior aos tratamentos, cilindros dos cimentos resinosos (0,8 mm/1,5 mm) foram confeccionad... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Objective: to evaluate the influence of surface treatment with non - thermal argon plasma (PLA) on bond strength of resin cements to enamel, dentin and lithium disilicate glass ceramic; and, to observe, through Fourier Transform Modified Infrared Spectroscopy (FTIR), the inorganic compounds and through gas chromatography, the alteration of the volatile organic compounds, on the enamel and dentin, under the experimental conditions. Material and Method: Three resin cements: Variolink Esthetic LC and N (Ivoclar Vivadent) and Panavia V5 (Kuraray) were evaluated. Twenty hundred and forty bovine teeth were used, among which 150 specimens with enamel surface exposure and 90 with dentine exposure. One hundred and fifty lithium disilicate glass ceramic slices (12 x 14 x 0.5 mm) were obtained. The groups were divided according to the substrate and surface treatment. The treatments for enamel and dentin surfaces were: EA (enamel / phosphoric acid); DA (dentin / phosphoric acid); EPS (enamel / PLA 30 s); EPM (enamel / PLA 1 min); DPS (dentin / PLA 30 s); EAPS (enamel / phosphoric acid / PLA 30 s) and EAPM (enamel / phosphoric acid / PLA 1 min); and, DAPS (dentin / phosphoric acid / PLA 30 s). The treatments for the ceramic surfaces were: CA (ceramic / hydrofluoric acid), CPS (ceramic / PLA 30 s); CPM (ceramic / PLA 1 min); CAPS (ceramic / hydrofluoric acid / PLA 30s) and CAPM (ceramic / hydrofluoric acid / PLA 1 min). After the treatments, resin cement cylinders (0.8 mm / 1.5 mm) were bu... (Complete abstract click electronic access below) / Doutor

Le remplacement valvulaire aortique percutané (TAVI) est une thérapie qui s’impose de plus en plus chez les patients porteurs d’une sténose aortique sévère. Toutefois, un nombre croissant d’études démontre que l’utilisation, crimping (sertissage) et déploiement, de ces bioprothèses est induit une altération de la structure de leurs feuillets péricardiques. Ce qui soulève la question de la durabilité à long-terme de ces dispositifs.Dans les travaux de cette thèse, nous avons développé des outils permettant d’analyser le traumatisme subi par les feuillets de péricardes.La première stratégie visait à déterminer les différences de comportements des péricardes bovins et porcins en matière de diffusion vis à vis de différents solutés. Nous avons pu mettre en évidence que la perméabilité du péricarde porcin était plus élevée (en moyenne 5-fois) et plus hétérogène comparativement à celle du péricarde bovin. La seconde stratégie consistait à caractériser, à l’aide des outils développés, les lésions traumatiques induites lors du déploiement des prothèses auto-expansible ou déployable par inflation d’un ballon. Quelque soit le type de prothèses utilisées, une altération de la perméabilité membranaire des péricardes a été observée après leurs déploiements.La dernière stratégie était de déterminer si le crimping de bioprothèses auto-expansibles pouvait entrainer une calcification plus importante des feuillets péricardiques. Un modèle d’évaluation de la calcification in-vivo chez le lapin a été utilisé. Cette étude à permis d’observer que le taux de calcium ainsi que la minéralisation du péricarde n’étaient pas affectées par le crimping. / Transcatheter aortic valve replacement (TAVR) is a growing therapy indicated to treat severe aortic valve stenosis. However, an increasing number of studies demonstrated that crimping and deployment of these bioprostheses induce structural alterations of the pericardial leaflets. These observations raise interrogations concerning the long-term durability of these devices.In this thesis works, we developed tools to analyze pericardial leaflets injuries.The first strategy consisted to determine the differences between bovine and porcine pericardium toward the filtration of various solute.It was possible to observe that porcine pericardium hydraulic conductance was higher (5-folds) and more heterogeneous than bovine pericardium.The second strategy consisted to characterize the lesions induced by deployment of self and balloon expandable valved-stents.After deployment, both types of valved-stents showed an alteration of their pericardial hydraulic conductance.The last strategy was to determine if self-expandable valved-stents crimping could increase their pericardial leaflets calcification. The rabbit model was used as an in-vivo evaluation model.This study showed that the calcium concentration and the mineralization of their pericardial leaflets were unaffected by valved-stents crimping.

Statistical physics has been the foundation for much of our understanding about plasma physics. Often, plasma physics phenomena are explained using statistical physics principles and theories. Here, I reverse this paradigm to instead use plasma experiments to test statistical physics principles. In this thesis, I test statistical physics principles with an experimental dusty plasma, which is a four-component mixture of micron-sized ``dust'' particles, electrons, ions, and neutral gas molecules. When immersed in the plasma, the dust particles acquire large negative charges, since they accumulate more electrons than ions. Due to their large electric charges, the dust particles have interparticle potential energies that greatly exceed their kinetic energies, so that the collection of dust particles is considered to be a strongly coupled plasma. Like other strongly coupled plasma, the collection of dust particles can exhibit solid-like or liquid-like behavior. A key advantage offered by dusty plasma experiments is the ability to track the motion of individual dust particles. Dust particles are sufficiently large to allow for direct imaging using a video camera, so that time series data can be obtained for particle positions and velocities. These particle-level data provide a richer description of the dynamics and structure than can be obtained for most other strongly coupled plasmas, simple liquids, or solid materials. In particular, the particle-level data of positions and velocities are often required inputs for testing statistical physics theories or principles. The dusty plasma data I analyze are from the experiment of Haralson~\textit{et al.} [1,2], where dust particles were electrically levitated in a single horizontal layer within a vacuum chamber. The collection of dust particles initially settled into a crystalline lattice with solid-like behavior. To reach a liquid-like state, or to drive a shear flow, dust particles were manipulated using the radiation pressure force of lasers. In this thesis, I test three different statistical physics principles using an experimental dusty plasma. First, I test the fluctuation theorem, which was first was presented in 1993 by Evans, Cohen, and Morriss [3]. The fluctuation theorem, which is one of the most important recent developments in statistical physics, quantifies the probability that the entropy production rate will temporarily fluctuate to negative values in ``violations'' of the second law of thermodynamics. The original formulation of the fluctuation theorem described the entropy production due to viscous heating in a shear flow; this version of the fluctuation theorem had never been experimentally demonstrated in a liquid of any kind. In Chapter 2, I provide the first such demonstration by showing that the entropy production rate in a liquid-like dusty plasma shear flow satisfies the fluctuation theorem. This result also serves as the first demonstration that a strongly coupled plasma obeys the fluctuation theorem. Second, I measure the Einstein frequency $\Omega_E$, which describes the stochastic process of collisions in a strongly coupled plasma, and I compare my measurement to predictions made in the literature that used simulation data. Often, for weakly coupled plasma, a collision frequency is obtained to provide a measure of the strength of particle-particle interactions. However, for strongly coupled plasma (and likewise for liquids and solids), a collision frequency is not well defined since collisions are multibody and occur continuously. Another quantity is needed to describe the strength of particle-particle interactions. I propose that the Einstein frequency $\Omega_E$, a concept more commonly used in solid physics, is better suited for describing particle-particle interactions in a strongly coupled plasma. In Chapter 3, I present and use a new method to obtain the Einstein frequency of a 2D dusty plasma in both a liquid-like state and a crystalline state. My measurement of the Einstein frequency, which serves as a proxy for a collision frequency, is consistent with simulation predictions in the literature. Third, I present particle-coordination survival functions, which provide a richer description of microscopic dynamics in a liquid than the commonly used relaxation time. Relaxation times have been used, for example the Maxwell relaxation time, to describe the characteristic time scale for the crossover between elastic and viscous behavior in viscoelastic liquids. However, relaxation times are single-value measures that cannot fully describe the complexity of a liquid. In Chapter 4, using a survival function that retains temporal information about the local structural in a liquid, I discover that the microscopic arrangements in a liquid-like 2D dusty plasma have multiple time scales. Unexpectedly, non-defects have two time scales, while defects have one. My survival functions are time-series graphs of the probability that a particle's number of nearest neighbors, i.e., its coordination, remains the same. The two time scales for non-defects are revealed by an elbow in their survival-function curve. As a spinoff with a considerable amount of importance, I performed the simplest fluctuation theorem experiment to date, using an aerosol. An aerosol is simply a particle that is immersed in air. In Chapter 5, I show that the fluctuation theorem is applicable for an aerosol particle undergoing free-fall in air due to gravity. While the particle typically fell downwards, it is observed to occasionally fall upwards, against the force of gravity. For such upward displacements, the work done on the particle is negative, which is a temporary violation of the second law. I find that the probability of these temporarily violations obeys the work fluctuation theorem. This result also allowed an application: a novel diagnostic method to measure the mass of aerosol particles.