Le traitement de la corrosion constitue un enjeu économique, environnemental et de sécurité sanitaire. Plus largement utilisée à l’échelle industrielle, la protection par revêtements consiste à isoler le métal du milieu agressif par une couche adhérente, continue et imperméable. Ils doivent répondre à trois propriétés majeures : 1) être fortement adhérent au substrat métallique, 2) posséder de bonnes propriétés barrière pour limiter la pénétration de l’eau et des espèces agressives et 3) apporter un rôle d’inhibition de la corrosion. Cependant, la protection des surfaces métalliques par les techniques actuelles génère une pollution notable liée à l’usage de chromates. L’utilisation de polymères biosourcés et solubles en milieu aqueux serait un challenge et contribuerait à préserver l’environnement. Les polysaccharides comme le chitosane sont des macromolécules biodégradables et respectueuses de l'environnement possédant des propriétés d’anticorrosion et sont donc des alternatives envisageables. Ces travaux de thèse portent sur le développement de revêtements anticorrosion à base de chitosane. Le chitosane possède deux points faibles pour être utilisé comme revêtement contre la corrosion : 1) une adhésion insuffisante sur la surface des matériaux et 2) un caractère hydrophile. En conséquence, le chitosane a été modifié chimiquement afin d’augmenter son adhésion et ses propriétés barrières. Afin d’améliorer son adhésion sur des substrats métalliques, des groupements de type acide phosphonique ont été ajoutés via la réaction de Kabachnik-Fields sur le chitosane. L’élaboration d’un chitosane possédant des fonctions catéchol a été également discutée. Dans un premier temps, le chitosane modifié a été testé et caractérisé par spectroscopie d’impédance électrochimique (SIE) en tant qu’inhibiteur de corrosion puis des revêtements à partir de ce même chitosane ont été réalisés et leurs protections contre la corrosion ont été évaluées. Deux approches de mise en forme des revêtements ont été testées : par dip-coating et par la technique Layer-by-Layer (LbL). Différentes voies de fonctionnalisation du chitosane ont également été présenté afin d’augmenter les propriétés barrière du revêtement. La chimie de phthaloylation du chitosane a été décrite puis le greffage de chaînes hydrophobes a été étudié. / Corrosion treatment is an economic, environmental and health safety issue. More widely used on an industrial scale, coating protection consists in isolating the metal from the aggressive medium by an adherent, continuous and impermeable layer. They must have three major properties: 1) be strongly adherent to the metallic substrate, 2) have good barrier properties to limit the penetration of water and aggressive species and 3) provide a role in inhibiting corrosion. However, the protection of metal surfaces by current techniques generates significant pollution due to the use of chromates. The use of bio-based and soluble polymers in aqueous media would be a challenge and would contribute to preserving the environment. Polysaccharides such as chitosan are biodegradable and environmentally friendly macromolecules with anticorrosive properties and are therefore possible alternatives. These theses focus on the development of anticorrosion coatings based on chitosan. Chitosan has two weak points for use as a coating against corrosion: 1) insufficient adhesion on the surface of the materials and 2) hydrophilicity. As a result, chitosan has been chemically modified to increase its adhesion and barrier properties. In order to improve its adhesion on metal substrates, phosphonic acid groups have been added via the Kabachnik-Fields reaction on chitosan. The development of a chitosan with catechol functions was also discussed. Initially, the modified chitosan was tested and characterized by electrochemical impedance spectroscopy (EIS) as a corrosion inhibitor and coatings based on the same chitosan were made and their corrosion protection evaluated. Two approaches of coating elaborations were tested: dip-coating and Layer-by-Layer (LbL). Different ways of functionalizing chitosan have also been presented to increase the barrier properties of the coating. Phthaloylation chemistry of chitosan was described and hydrophobic chain grafting was studied.

Orientador: Ângela Cristina Cilense Zuanon / Resumo: O tratamento da dentina afetada e das lesões de mancha branca com agentes antibacterianos e remineralizadores tem sido uma alternativa eficaz na longevidade das restaurações, porém não há estudos em que um gel de uso odontológico seja composto por nanopartículas de dióxido de titânio (NPTiO2), hidroxiapatita (NPHA), óxido de zinco (NPZnO), vidro bioativo F 18 (VBF18) e fluoreto de sódio (NaF). O objetivo deste estudo foi avaliar a capacidade antibacteriana e remineralizadora de géis experimentais que compuseram os grupos G0- Glicerina (controle negativo), G1- NPHA 3%, G2- NPTiO2 3%, G3- NPZnO 3%, G4- VB F18 3%, G5- NaF 5%, G6- NPTiO2 + NaF 5%, G7- NPZnO 3% + NaF 5%, G8- CLX 0.2%, G9- NPHA 3% + NaF 5% e G10- VB F18 3% + NaF 5%, utilizados no tratamento prévio da dentina afetada antes do selamento da cavidade com cimento de ionômero de vidro (CIV) e na remineralização de lesões de mancha branca. Blocos de dentina e esmalte bovinos passaram por desafio cariogênio monoespécie (S. mutans) induzindo mancha branca em esmalte e cárie em dentina. Os espécimes (esmalte e dentina após remoção da dentina infectada) foram tratados com os géis experimentais e, os de dentina, restaurados com o CIV. Foi avaliada a atividade antibacteriana por meio do teste de halo de inibição e atividade antibiofilme, por meio contagem de unidades formadoras de colônias (UFC/ml), sendo o último também analisado em microscopia eletrônica de varredura (MEV). Todos espécimes foram submetidos aos testes de rugos... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Cette thèse porte sur l’élaboration et l’étude des performances de membranes d’ultrafiltration PVDF-TiO2 possédant des propriétés anti-colmatantes et photo-induites. La membrane est obtenue par application de la méthode de séparation de phases induite par un non-solvant sur un collodion de polyfuorure de vinylidène au sein duquel ont été incorporées des nanoparticules de TiO2. Il est montré : i) que la presence des nanoparticules de TiO2 les propriétés membranaires, et notamment le flux de perméat, par rapport à la membrane PVDF ; ii) que l’augmentation de la température de préparation de la membrane permettait de modifier la structure membranaire, en passant d’une morphologie constituée principalement de macrovides (dite en “doigts de gants”) à des températures basses à une morphologie spongieuse, contenant des pores de plus petite taille, à température élevée. Au-delà de la structure membranaire, des propriétés telles que la perméabilité, la porosité, la résistance mécanique, la cristallinité et les propriétés thermiques sont également influences par les changements de température de formation. Lorsque les membranes PVDF-TiO2 sont mises en oeuvre en mode photo-filtration (c.-à-d. filtration avec irradiation ultraviolette (UV) continue sur la membrane), le flux à l’eau pure de la membrane PVDF-TiO2 est encore augmenté, du fait du phénomène d’hydrophilicité photo-induite des nanoparticules de TiO2. Des premières estimations suggèrent que la photo-filtration par les membranes PVDF-TiO2 serait une économiquement rentable, car le gain en termes de filtration et qualité d’eau l’emporterait sur le cout énergétique induit par l’irradiation UV. En outre, l’efficacité de la photo-filtration a été évaluée avec des solutions d’alimentation synthétiques contenant des composés inorganiques et organiques représentatifs des eaux de surface. Il a été montré que si la plupart des ions inorganiques communément rencontrés dans l’eau potable n’ont aucun effet sur l’efficacité de la photo-filtration, la coexistence de Cu2+ et HCO3- dans l’eau d’alimentation entraîne un colmatage inorganique sévère qui inhibe le phénomène hydrophilicité photoinduite. En outre, la membrane PVDF-TiO2 présente également des flux plus élevés et une activité photocatalytique lors de la photo-filtration de solutions contenant des matières colmatantes organiques comme les acides humiques ou l’alginate de sodium. En conclusion, la membrane composite PVDF-TiO2 a démontré des propriétés et des performances significativement améliorées par rapport à la membrane PVDF, a fortioti lorsqu’elle est mise en oeuvre dans un système de photo-filtration sous irradiation UV. Ainsi, ce sont des matériaux prometteurs pour des applications membranaires en traitement de l’eau. / This thesis deals with the elaboration and performance of a specific type of ultrafiltration membrane with anti-fouling and photo-induced properties, the PVDF-TiO2 composite membrane. The membrane was fabricated via the nonsolvent-induced phase separation method by incorporating titanium dioxide (TiO2) nanoparticles into the polyvinylidene fluoride (PVDF) polymer matrix. The TiO2 nanoparticles played a significant role in facilitating the membrane formation process and improving the composite membrane properties compared to the neat PVDF membrane. It was demonstrated that, by changing the membrane preparation temperature, the membrane structure could be affected dramatically, notably the morphological dominance of finger-like macrovoids at lower temperatures and their diminution in both size and number when temperature increased. Other membrane properties also saw systematic transitions with changes in formation temperature, as characterized by permeability, porosity, mechanical strength, crystallinity, and thermal properties. In terms of performance, the PVDF-TiO2 membrane exhibited superior permeate flux compared to the neat PVDF membrane. More importantly, when being operated in photo-filtration mode (i.e. filtration with continuous ultraviolet (UV) irradiation on the membrane), the pure water flux of PVDF-TiO2 membrane could be further increased, thanks to the enhanced hydrophilicity of the membrane, which comes from the photo-induced hydrophilicity phenomenon of TiO2. Preliminary estimations suggest that photo-filtration is a cost-effective method, as the benefit from enhanced water output outweighs the extra energy demand for UV irradiation. Furthermore, the efficiency of photo-filtration was evaluated with synthetic feed solutions containing inorganic and organic contents representative in surface water. It was identified that, while most of the common inorganic ions in drinking water had no effects on photo-filtration efficiency, the coexistence of Cu2+ and HCO3- in the feed led to severe inorganic fouling and inhibited the photo-induced hydrophilicity phenomenon. Besides, the PVDF-TiO2 membrane also showed its stronger flux performance and photocatalytic activity during photo-filtration of solutions containing organic foulants like humic acids or sodium alginate. In conclusion, the PVDF-TiO2 composite membrane exhibited much improved properties and performance compared to the neat PVDF membrane, and even stronger performance when operated in photo-filtration mode. Thus, it is a promising candidate to be used in membrane-based applications for water treatment.

This work deals with the evolution of the topics of Anti-Semitism and Anti-Zionism in Czechoslovakia between the years 1945-1953. It is divided into three parts. The first part deals with the definition of the concepts of Zionism, Anti-Zionism and Anti-Semitism, thus comprising the theoretical framework of the thesis. The second part analyzes the political historical developments in the era of 1945-1953, during which the Communist Party seizes power. Described here is also the importance of the establishment of the State of Israel in the context of the development of Soviet-Israeli relations and Czechoslovak-Israeli relations. These relations later developed the attitudes towards the Jewish communities. In the third part, the work deals with the stance of the Communist Party of Czechoslovakia towards Jews. It views the stance as an overlapping combination of Anti-Semite and Anti-Zionist positions, which culminates in the political trials of the 1950s. It also shows an interesting contrast whereas during that same time, the Communists allowed the grand re-opening of the Pinkas Synagogue Memorial, honoring the victims of the Holocaust. The interplay between the Communists and Jews was neither wholly positive, nor entirely negative; both sides of the stance can be demonstrated. They are influenced by...

Magister Legum - LLM / Annually, money laundering costs global financial markets $2.5 trillion. Money laundering is especially problematic in that it results in a plethora of socioeconomic problems including poor economic performance and an upsurge in crime. In fact, predicate crimes such as corruption, drug trafficking, tax evasion, smuggling, fraud, and terrorism are so embedded within money laundering so much so that combatting either is a complicated task. Although it is a daunting endeavour, best practice teaches that multilateral and international cooperation are most effective at fighting money laundering. For that reason, establishing locally sensitive and yet internationally focussed anti-money laundering regimes is a priority for numerous countries.

We report on 2 cases of chronic relapsing thrombotic thrombocytopenic purpura, in which anti-phospholipid antibodies were also found. The first patient was felt to have the antiphospholipid antibody syndrome, while the second patient had anti-phospholipid antibodies without clinical manifestations of the anti-phospholipid antibody syndrome. We discuss chronic relapsing thrombotic thrombocytopenic purpura and the anti-phospholipid antibody syndrome. Furthermore, we introduce the possibility of an association between chronic relapsing thrombotic thrombocytopenic purpura and the presence of anti-phospholipid antibodies.

No description available.

This study sets out to explore Swedish anti-trafficking policy, both how it is defined in official policy-documents as well as on the local level. A brief overview of the history of anti-trafficking policy and contemporary international measures relating to Swedish legislation on trafficking provides a glimpse into the contested meanings of these measures. This aspect finds foothold in the theoretical framework and is further developed throughout the study. By combining qualitative content analysis and interpretative policy analysis with interviews conducted among practitioners working in this field in a local context, Swedish anti-trafficking policy is explored on different levels. The analysis of the legal Swedish framework and one national anti-trafficking action plan suggests that the Swedish fight against trafficking is strictly interlinked with another fight, one against prostitution. However, there seems to be a discrepancy between the theory and practice of this national policy. In the interviews with the local practitioners it is revealed that what is framed as anti-trafficking policy in official policy-documents is both contested and reconstructed on the local level. Thus, this study argues that Swedish anti-trafficking policy is far from a straightforward matter.

The most ubiquitous mode of frost formation on substrates is condensation frosting, where dew drops condense on a supercooled surface and subsequently freeze, and has been known since the time of Aristotle. The physics of frost incipience at a microscopic scale has, nevertheless, eluded researchers because of an unjustified ansatz regarding the primary mechanism of condensation frosting. It was widely assumed that during condensation frosting each supercooled droplet in the condensate population freezes in isolation by heterogeneous nucleation at the solid-liquid interface, quite analogous to the mechanism of icing. This assumption has very recently been invalidated with strong experimental evidence which shows that only a single droplet has to freeze by heterogeneous nucleation (typically by edge effects) in order to initiate condensation frosting in a supercooled condensate population. Once a droplet has frozen, it subsequently grows an ice bridge towards its nearest neighboring liquid droplet, freezing it in the process. Thus ensues a chain reaction of ice bridging where the newly frozen droplets grow ice bridges toward their nearest neighbor liquid droplets forming a percolating network of interconnected frozen droplets. Not always are these ice bridges successful in connecting to their adjacent liquid droplets. Sometimes the liquid droplet can completely evaporate before the ice bridges can connect, thus forming a local dry region in the vicinity of the ice bridge. In this work, we first formulate a thermodynamic framework in order to understand the localized vapor pressure gradients that emerge in mixed-mode phase-change systems and govern condensation and frost phenomena. Following this, we study droplet pair interactions between a frozen droplet and a liquid droplet to understand the physics behind the local ice bridge connections. We discuss the emergent scaling laws in ice bridging dynamics, their relative size dependencies, and growth rates. Thereafter, we show how with spatial control of interdroplet distances in a supercooled condensate and temporal control of the first freezing event, we can tune global frost propagation on a substrate and even cause a global failure of all ice bridges to create a dry zone. Subsequently, we perform a systematic study of dry zones and derive a scaling law for dry zones that collapses all of our experimental data spanning a wide parameter space. We then show that almost always the underlying mechanism behind the formation of dry zones around any hygroscopic droplet is inhibition of growth and not inhibition of nucleation. We end with a discussion and preliminary results of our proposed anti-frosting surface that uses ice itself to prevent frost. / Master of Science

Matter on earth exists mostly in three different phases of solid, liquid, and gas. With extreme amounts of energy, temperature, or pressure, a matter can be changed between the phases. Six different types of phase-change phenomena are possible: freezing (the substance changes from a liquid to a solid), melting (solid to liquid), condensation (gas to liquid), vaporization (liquid to gas), sublimation (solid to gas), and desublimation (gas to solid). Another form of phase change which will be discussed here is the wetting or dewetting transitions of a superhydrophobic surface, in which the phase residing within the surface structure switches between vapor and liquid. Phase transition phenomena frequently occur in our daily life; examples include: a ``liquid'' to ``solid'' transition when cars decrease their distance at a traffic light, solidification of liquids droplets during winter months, and the dancing of droplets on a non-sticking pan. In this dissertation we will address seven different phase-change problems occurring in nature. We unveil completely new forms of phase-change phenomena that exhibit rich physical behavior. For example, during traffic flow, drivers keep a large distance from the vehicle in front of them to ensure safe driving. When vehicles come to a stop, for example at a red light, drivers voluntarily induce a ``phase transition'' from this ``liquid phase'' to a close-packed ``solid phase''. This phase transition is motivated by the intuition that traveling as far as possible before stopping will minimize the overall travel time. However, we are going to investigate this phase-change process and show that this long standing intuition is wrong. Phase-change of solidification will be discussed for different problems. Moreover, the complex physics of oil as it wicks up sheets of frost and freezing of bubble unveil completely new forms of multiphase flows that exhibit rich physical behavior. Finally, the ``Cassie'' to ``Wenzel'' transition will be investigated for layered nano-textured surfaces. These phenomena will be modeled using thermodynamics and fluid mechanics equations. / Doctor of Philosophy / The main focus of this dissertation is on the dynamical phase change phenomena occurring in nature. First, we study the solid to liquid phase change of group of people moving from rest. We show that increasing the packing density of vehicles at a stop-and-go motion (e.g., vehicles at a traffic light) would not increase the efficiency of the flow once it is resumed. Second, we present a passive anti-frosting surfaces just by using the chemistry of ice. We show how the in-plane frost growth can be passively suppressed by patterning arrays of microscopic ice stripes across a surface. Third, we elucidate how bubbles deposited on a chilled and icy substrate freeze in different ambient conditions. We reveal the various phenomena that govern how soap bubbles freeze and produce a variety of beautiful effects. Fourth, we will study oil-ice interactions which are important for the emerging science of using oil-impregnated surfaces for anti-icing and anti-frosting applications, where oil drainage from the surface due to wicking onto ice is a pressing issue. We observe oil as it wicks up sheets of frost grown on aluminum surfaces of varying wettability: superhydrophilic, hydrophilic, hydrophobic, and superhydrophobic. Fifth, we study the effect of topography of the nanopillars on dynamics of jumping droplets. The critical diameter for jumping to occur was observed to be highly dependent on the height and diameter of the nanopillars, with droplets as small as 2 µm jumping on the surface with the tallest and most slender pillars. Sixth, we show that micrometric condensate spontaneously launches several millimeters from a wheat leaf’s surface, taking adhered pathogenic spores with it. We quantify spore liberation rates of order 10 cm⁻² hr⁻¹ during a dew cycle. Finally, inspired by duck feathers, two-tier porous superhydrophobic surfaces were fabricated to serve as synthetic mimics with a controlled surface structure. We show the effect of layers of feathers on energy barrier for the wetting transition.