Orientadores: Cristiano Monteiro de Barros Codeiro, Marcos Antonio Ruggieri Franco / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-20T13:14:05Z (GMT). No. of bitstreams: 1 ValenzuelaEspinel_YovannyAlexander_M.pdf: 51370027 bytes, checksum: 2f925ea5d4b6a8642e1244ad21e8e82b (MD5) Previous issue date: 2011 / Resumo: Foram realizados estudos sobre o controle de propriedades ópticas, por meio de pressão, e sensibilidade à pressão com fibras de cristal fotônico (PCF). No primeiro caso foi demonstrado por meio de simulações, uma nova forma para obter e sintonizar com pressão hidrostática externa o estado monomodo e única polarização em fibras PCF de polimetilmetacritalo (PMMA). Em relação à sensibilidade à pressão hidrostática, o comportamento espectral do coeficiente de sensibilidade de varias fibras PCF em sílica, Cs = (?? / ?P) (onde ?? é a variação num mínimo do espectro de transmissão de uma fibra PCF que acontece quando a pressão hidrostática externa muda em LlP), é calculado teoricamente e corroborado experimentalmente. Com a finalidade de estudar teoricamente o coeficiente Cs, a birrefringência de grupo e a sensibilidade da birrefringência modal de fase à pressão são simuladas para as fibras. Expressões analíticas do coeficiente Cs na aproximação de primeira e segunda ordem são calculadas. Nas duas aproximações é confirmado um aumento do Cs para comprimentos de onda no visível devido à birrefringência de grupo. Para baixas pressões, tal comportamento é corroborado experimentalmente. Segundo a literatura apresentada até agora a possibilidade de otimizar o coeficiente Cs, fazendo uso da birrefringência de grupo no visível e ao mesmo tempo incorporando geometrias com uma alta anisotropia geométrica para aumentar a sensibilidade da birrefringência modal de fase à pressão, não tem sido explorada. Na aproximação de segunda ordem do coeficiente Cs são incorporadas as mudanças do comprimento de onda e da pressão e são comparadas com a aproximação de primeira ordem. Cálculos analíticos foram feitos e apresentados nos Apêndices B e C. As equações do efeito fotoelástico, determinantes para realizar as simulações com o software (COMSOL 3.5a), são apresentadas no Apêndice B, relações que descrevem o coeficiente Cs de fibras PCF são apresentadas no (Apêndice C) / Abstract: Abstract Studies about both the active control of optical properties by means of external hydrostatic pressure and pressure sensitivity in photonic crystal fibers (PCFs) were made. In the first case, a new form to obtain and tune, by using pressure, the single-mode single-polarization state in microstructured polymer optical fibers (mPOFs) is demonstrated by simulations. In relation to pressure sensitivity, the spectral behavior of the sensitivity coefficient of some PCFs in silica, Cs = (?? / ?P) (where ?? é is the change in a minimum of the transmission spectrum for a PCF as a consequence of the change in the external hydrostatic pressure 11P that is applied on the fiber), is calculated and corroborated experimentally. In order to investigate the coefficient Cs, the group birefringence and the sensitivity of phase modal birefringence to pressure are calculated in the fibers. Analytical expressions for the coefficient Cs in the first and second order approximation are calculated. In these two approximations an increase of the coefficient Cs is confirmed to wavelengths in the visible. To low pressures this behavior is corroborated experimentally. At the best of our knowledge, the possibility to optimize the coefficient (Cs) by using the group birefringence and geometries with high geometric anisotropy to enhancing the sensitivity of phase modal birefringence to pressure has not been investigated. In the coefficient Cs with the second order approximation are incorporated the changes of the wavelength and pressure and are compared with the first approximation. On the other hand, analytic calculates are realized in the Appendixes B and C. The equations related to the photoelastic effect were calculates (Appendix B). Finally, the relations that describing the behavior of pressure sensitivity also were calculates (Appendix C) / Mestrado / Física / Mestra em Física

Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished

Extracellular vesicles (exosomes) are the subject of current nephrology proteomics research as they are considered as a promising source of potential biomarkers of kidney disease. This work is focused on discovery of the most appropriate procedure for the urinary exosomes isolation. We have compared already described methods, based on different physicochemical principles of isolation: hydrostatic filtration dialysis (HFD), differential ultracentrifugation, ultrafiltration through a 100 kDa filter, or sample precipitation with Total Exosome Isolation (from urine) kit. Characterization of individual isolated exosomal fractions was performed using SDS-PAGE method (presence of contaminating proteins), western blot analysis (detection of exosomal markers TSG101, alix), nanoparticle tracking analysis (NTA, vesicle size and concentration) or transmission electron microscopy (TEM, vesicles morphology). Due to the presence of contaminating proteins in urine samples, which could distort the results of subsequent proteomic assays, the conditions for the cleavage of undesirable proteins by proteinase K prior to their own isolation were optimized. It has been found that the best yield and purity of the isolated exosomal fractions were provided by a process combining HFD with differential ultracentrifugation...

Suite à la découverte récente des sources hydrothermales les plus profondes de la planète au niveau de laFosse des Caïmans, des échantillons hydrothermaux y ont été prélevés en vue de cultiver des microorganismes de ce site encore peu documenté. Des cultures d’enrichissement ont été réalisées à partir de ces échantillons en vue d’isoler de nouveaux taxons microbiens ayant des métabolismes clés des cycles biogéochimiques du soufre et du carbone ou une physiologie particulière (piézophilie). Parmi les isolats obtenus, il y avait notamment une nouvelle archée hyperthermophile anaérobie sulfo-réductrice, désignée comme CDGST, qui provenait du champ hydrothermal Beebe, à 4964 m de profondeur. Cette souche, affiliée au genre Thermococcus, présentait une certaine plasticité physiologique et se démarquait de ses plus proches parents du point de vue de sa physiologie.Elle a été caractérisée en détails aux niveaux métabolique, physiologique et génomique. Cette souche estpiézophile et possède la plus large gamme de pression de croissance jamais décrite pour un organisme. Elle se développe de manière optimale à 75°C, pH 6,0 et sous une pression hydrostatique de 50 MPa, la pression in situ de son habitat naturel. Elle appartient à une nouvelle espèce qui a été appelée Thermococcus piezophilus sp.nov. Son génome a été séquencé et annoté.La croissance de ce nouvel isolat est efficace de pression atmosphérique jusqu’à au moins 120 MPa, et la souche croît avec plus de difficultés jusqu'à 130 MPa. Aucun autre microorganisme, qu’il soit psychrophile, mésophile ou hyperthermophile ne possède une telle gamme de pression de croissance. Pour cette raison, les mécanismes d’adaptation de cette souche à la pression ont été étudiés par une approche de transcriptomique.Cette souche s’adapte aux variations de pression notamment en modulant sa production et sa conversion d’énergie (transporteurs, hydrogénases, etc.) en fonction de la pression. / Following the recent discovery of the world’s deepest hydrothermal vents at the Cayman Trough, hydrothermal samples were taken for culturing microorganisms of this site still poorly documented. Enrichment cultures were performed using these samples to isolate new microbial taxa having key metabolisms of biogeochemical cycles of carbon and sulfur or a particular physiology (piezophily). Among the isolates, there was a new hyperthermophilic and anaerobic sulfur-reducing archaea, designated as CDGST, originating from the hydrothermal field Beebe, at 4964 m depth. This strain belonged to the Thermococcus genus. It exhibited some physiological plasticity and was distinguishable from its closest relatives from the point of view of its physiology. It has been characterized in great details at metabolic, physiological and genomics levels. This strain is piezophilic and has the broadest range pressure for growth ever described for an organism. It grows optimally at 75°C, pH 6.0 and under a hydrostatic pressure of 50 MPa, the in situ pressure of its natural habitat. It belongs to a new species that was called Thermococcus piezophilus sp. nov. Its genome has been sequenced and annotated.The growth of this new isolate is effective from atmospheric pressure to at least 120 MPa, and the strain grows with more difficulties up to 130 MPa. No other organism, whether psychrophilic, mesophilic or hyperthermophilic has such a range of growth pressure. For this reason, the adaptation mechanisms to pressure of the strain were studied by a transcriptomic approach. This strain adapts to pressure variations, by modulating notably its energy production and energy conversion (carriers, hydrogenases, etc.) depending on the pressure.

La mise en œuvre des hautes pressions permet d'inactiver des micro-organismes contaminants (levures, bactéries, spores, virus…) au sein de divers milieux. Cette technologie a tout d'abord été utilisée puis développée à l'échelle industrielle pour décontaminer des produits alimentaires. Du fait de la faible énergie générée par les hautes pressions, seules les liaisons faibles et correspondant à une valeur de ?V négative sont altérées, ce qui, en outre, ouvrait la voie à de nombreuses applications biologiques. L'objectif de cette thèse était d'inactiver l'ensemble des micro-organismes pathogènes au sein d'un produit sanguin : le plasma. L’enjeu principal était d'une part de sauvegarder la fonctionnalité des principales protéines contenues dans le plasma (facteurs de coagulation notamment) et d'autre part d'inactiver les micro-organismes contaminants. Afin d’atteindre cet équilibre, plusieurs paramètres ont été utilisés : - la valeur de la pression (de 100 à 300 MPa), - la durée du traitement, - les températures négatives… Plusieurs résultats originaux seront présentés, notamment en ce qui concerne la différence de sensibilité aux hautes pressions des protéines d'une part et l'inactivation de micro-organismes d'autre part. / High hydrostatic pressure (HHP) has shown its capacity to inactivate contaminating micro-organisms (yeasts, bacteria, spores, viruses…) present in various media. This technology has been first used and developed to an industrial scale for the food industry. Because of the low energy raised using high pressure, only weak interactions characterized by a negative ?V will be altered. This statement opens the way to numerous applications in the biology field. The objective of this PhD work was to inactivate all the pathogens that may contaminate blood products, and blood plasma in particular. The main challenge was to inactivate the contaminating micro-organisms while maintaining the activity of the plasma proteins (such as blood coagulation factors). To achieve this balance, several parameters were used: - the pressure value (from 100 to 300 MPa), - the treatment duration, - negative temperatures… Some original results will be presented, concerning differences in the high pressure sensitivity of proteins and the inactivation of pathogens.

Les matériaux aujourd'hui utilisés pour l'isolation thermique en milieu aquatique sous pression hydrostatique sont soit des mousses souples à base de caoutchoucs, soit des mousses rigides, notamment syntactiques, selon la profondeur. Ces matériaux souples ont été analysés par des tests mécaniques et thermiques classiques. Cependant, les protocoles et valeurs relevées ont été adaptés à l'usage final du produit, et plus particulièrement à l'environnement aquatique en surface et en profondeur. Les relations entre les différentes caractéristiques (structures et propriétés) de ces matériaux ont été étudiées afin de définir les propriétés adéquates selon des critères pertinents. Pour mettre en évidence les propriétés thermiques sous pression hydrostatique, un outil de test a de plus été développé : une enceinte de test hyperbare innovante, pour l'évaluation de la résistance thermique et de l'épaisseur sous pression d'eau entre 0 et 50 m de profondeur. Les points forts et faibles des matières classiquement utilisées ont été clairement établis. L'analyse de ces résultats a permis d'identifier un concept de matériau composite propre à l'usage défini. Une matière innovante a été conçue en fonction : une mousse syntactique. En variant le type de particules additionnées à une matrice thermoplastique élastomère, la structure cellulaire a été affinée pour obtenir un comportement identique en milieu aquatique, en surface comme en profondeur. En parallèle de sa production industrielle, cette matière a été testée afin d'identifier les relations entre structures et propriétés. / Materials nowadays used for thermal insulation in aquatic environment under hydrostatic pressure are either rubber flexible foams or rigid foams, especially syntactic foams, depending on depth. These flexible materials were analyzed through classical mechanical and thermal tests. However, methods and results were adapted to the final usage of the product, particularly to the aquatic environment at the surface and under depth. Relationships between structures and properties characteristics were studied to define appropriate properties within relevant criteria. Moreover, to underline thermal properties under hydrostatic pressure, a testing instrument has been developed: an innovating hyperbaric test chamber, dedicated to under water pressure thermal resistance and thickness measurements, from 0 to 50 m depth. Strengths and weak points of these classical materials have been clearly established. Results analysis lead to a new concept of composite material for the defined usage. This innovating material, a syntactic foam, has been developed. By varying the particle type added to a thermoplastic elastomer matrix, the cellular structure has been refined in order to obtain a similar behaviour in aquatic environment, at the surface like in depth. This material has been tested, parallel to its industrial production, to identify relationships between structures and properties.

This master thesis deals with design of hydrostatic drive for harvester. It contains calculations of parameters from current drive like speed, hydraulic losses and tractive effort. Because now these parameters are insufficient in next part of work is proposed few options how to achieve required parameters. In selected cases are made calculations and based on the results are recommended two options for realization.

Diplomová práce se zabývá modifikací stávající pozemní verze letounu EV-55 pro možnost přistání na vodní hladině. Snahou je najít takovou variantu, která nepovede k výrazným konstrukčním zásahům do draku letounu a bude vyhovovat stavebnímu předpisu CS 23, zejména požadavkům týkající se plovatelnosti a stability na vodě. Je proveden hmotový rozbor modifikované verze a s tím související omezení hmotové obálky a rozsahu centráží. Zatížení od vody je spočítáno v souladu s CS 23. Pro toto zatížení je následně navrhnuto konstrukční řešení uchycení plováků k trupu a provedena pevnostní kontrola jednotlivých prvků a spojovacích uzlů. Tyto hodnoty jsou dále porovnány s pozemními případy zatížení a stanoveny součinitele rezerv. V závěru jsou spočítány letové výkony: maximální horizontální rychlost, stoupavost, dolet a vytrvalost.

La plupart des matériaux étudiés en physique de la matière condensée sont à base de fermions massifs vérifiant les relations de dispersion paraboliques usuelles. Récemment, sont apparus un certain nombre de matériaux dotés de relations de dispersion linéaires : le graphène, système purement bidimensionnel et les isolants topologiques, composés tridimensionnels à base de Bismuth où les fermions de Dirac surfaciques coexistent avec les fermions massifs volumiques. À côté de ces deux grandes familles de matériaux de Dirac, on trouve le composé organique α-(BEDT-TTF)2I3, un système quasi-bidimensionnel du point de vue du transport électronique en raison de sa structure cristalline lamellaire et qui présente une phase de Dirac sous forte pression hydrostatique (P>1,5 GPa). Cette phase de Dirac est singulière puisque ses cônes de Dirac sont inclinés, et donc fortement anisotropes, et qu'ils émergent aux côtés d'une bande de porteurs de charge massifs. Ce travail de thèse porte ainsi sur l'étude, à la fois expérimentale et théorique, des effets des spécificités de la phase de Dirac du α-(BEDT-TTF)2I3 sur son transport électronique en régime quantique. Il examine notamment plusieurs modèles théoriques pour tenter d'interpréter les oscillations quantiques apériodiques mesurées dans le composé organique, ainsi que l'impact de l'inclinaison des cônes de Dirac. Les effets de dopage, surfacique et volumique, sur le α-(BEDT-TTF)2I3 sont également discutés. / The physics of most of the materials studied within condensed matter are based on massive fermions which verify the usual parabolic dispersion relations. Recently, a certain number of materials with linear dispersion relation have appeared: graphene, purely bidimensional and topological insulators, tridimensional compounds based on Bismuth where the surfacic Dirac fermions coexist with bulk massive fermions. Alongside these two families of Dirac materials, there is the organic α-(BEDT-TTF)2I3 compound, a quasi-bidimensional system from an electronic transport point of view because of its lamellar crystalline structure and which exhibits a Dirac phase under high hydrostatic pressure (P>1,5 GPa). This Dirac phase is singular: the Dirac cones are tilted, and highly anisotropic, and they emerge with a massive band. This work is then focus on the study, experimentally and theoretically, of the effects of the α-(BEDT-TTF)2I3 Dirac phase specificities on its electronical transport in quantum regime. It examines particularly several theoretical models to understand the aperiodic quantum oscillations measured in the organic compound, and the impact of Dirac cones tilting. Doping effects, surfacic and in the bulk, on the α-(BEDT-TTF)2I3 are also discussed.

The diploma thesis is focused on the study of pressure-induced changes in a behavior of RECo2-type compounds. HoCo2 and its substitution of Si instead of Co in Ho(Co1-xSix)2, x = 0,025 were chosen as a representative compounds from this family of materials. Measurements of electric resistivity, heat capacity, magnetization and AC magnetic susceptibility under ambient pressure showed presence of three magnetic transitions for both samples: the change of the easy magnetization direction at TR ~ 16 K, the Curie temperature TC ~ 80 K and the flipping of magnetization of Co magnetic moments into the parallel direction with Ho magnetic moments at Tf ~ 125 K for HoCo2. Under hydrostatic pressures up to 3 GPa, the TR shifts to higher temperatures whereas TC and Tf, both decrease. This probably occurs due to the weakening of the Co magnetism and the strength of exchange interaction between Ho-Co sublattices. The experiment of muon spin rotation demonstrates a pressure influence to the decay of Co magnetic clusters, which occurs at lower temperatures with increasing pressure. It is evident that the hydrostatic pressure directly influences the exchange interaction between Co-Co.