L’altération chimique et l’érosion physique de la croûte continentale mobilisent de grandes quantités de matière sous formes solide et dissoute. Première productrice de sédiments sur le globe, la chaîne Himalayenne délivre ~1 Gt/a de sédiments aux océans. L'importance des différents facteurs qui contrôlent les flux érodés et celle des processus d’érosion (glaciers, glissements de terrain, sols) sont pourtant encore mal définies. Il en va ainsi des facteurs climatiques, en particulier de leur impact au cours des transitions climatiques. Afin de répondre à ces questions, ce travail s’attache à comparer la composition géochimique des produits de l’érosion à celles des sédiments actuels de rivière et des archives sédimentaires de la plaine du Gange. Un premier bilan des processus d’érosion a été établi petite échelle dans le bassin Haut-Himalayan de la Khudi. L’érosion actuelle conséquente de ce bassin de ~3mm/a se produit lors de la mousson, correspond pour l'essentiel à l’érosion des sols et surtout à l'intense activité d'une zone de glissement de terrain. Grâce au développement d'une nouvelle méthode de destruction de la matière organique, la mesure de l’hydratation des silicates a pu être utilisée comme traceur inédit des sols. Sur cette base, l’inversion des compositions des sédiments de la rivière démontre que l’érosion physique est dominée à ~80% par le glissement de terrain, l’érosion de sols étant mineure et comparable aux taux d’érosion des autres bassins alentours. L’érosion chimique qui conduit à un flux d'éléments dissous de 7.9 kt/a (soit une érosion équivalente de 0.02 mm/a) semble dériver de l’altération profonde du substrat rocheux. Néanmoins les flux d'éléments dissous dessinent également une relation marquée avec les flux particulaires durant la mousson, suggérant une altération additionnelle des sédiments au cours du transport fluvial. Une approche similaire a ensuite été menée à l’échelle plus vaste du bassin de la Narayani drainant l’ensemble du Népal central. Grâce à des mesures de courant par ADCP combinées à l’échantillonnage de sédiments en profondeur, un modèle de transport sédimentaire a été utilisé pour intégrer les flux sédimentaires en profondeur et ainsi réviser le taux d’érosion moyen sur le bassin versant à une valeur de ~1.7 mm/a, proche des taux d'érosion long-terme. Un système géochimique associant la mesure du δD des silicates associée aux concentrations en carbonate s’est révélé un traceur diagnostique de l’érosion glaciaire dans le Nord du bassin, tandis que la teneur en matière organique du sédiment a pu être utilisée comme traceur des sols. L’analyse temporelle des flux de sédiments, de leur composition et du signal granulométrique, a ainsi permis d’établir que seule une faible fraction des sédiments (<20%) provenait de l’érosion par les glaciers et les sols. À l'échelle du Népal central, l’érosion physique semble donc également dominée par les glissements déclenchés lors de la période de mousson. Le grand cône alluvial de la Narayani-Gandak, situé au débouché de cette rivière dans la plaine du Ganges, a enregistré l’histoire récente de l’érosion du Népal central. Trois forages réalisés dans ce méga-cône permettent ainsi d'étudier l'évolution de l'altération et de l'érosion en Himalaya au cours du tardi-Pléistocène. Ces dépôts sédimentaires révèlent une étonnante stabilité depuis ~45 ka de la géochimie, des provenances et du degré d’altération des sédiments. Seule l’intensité de l’érosion mesurée par isotopes cosmogéniques semble augmenter au cours de l’Holocène. Par contraste, l’évolution très récente de la distribution de l’érosion dans la chaîne est marquée par un accroissement (x3) de la proportion de matériel des régions basses et plus peuplées de l'Himalaya, montrant que les activités anthropiques, via notamment une forte croissance du réseau routier durant la dernière décennie, [...] / Chemical weathering and physical erosion of the continental crust mobilise huge amounts of both solid and dissolved material. As the first sediment generator on the Earth, the Himalayan range releases around 1 Gt/y of sediment into the ocean. The relative influence of the different factors that control the eroded fluxes and the importance of the erosion processes (such as landslides, glaciers, soils) are as yet poorly understood. The same is true of the climatic factors, especially regarding their impact during climatic transition periods. In order to address those questions, this work focuses on comparing the geochemical composition of erosion products to the composition of present river sediment and of sedimentary records in the Ganga Plain. A first budget of the erosion processes was done on a small scale in the Khudi catchment of Higher Himalaya. The total present-day erosion is considerable, at around 3 mm/y and takes place during the monsoon. It is mainly linked to the soils erosion and more importantly to the intense activity of a landsliding area. The development of a new method for the destruction of organic matter enabled the use of silicates hydration as a tracer for soils. Based on this method, a mathematical inversion of the sediment compositions was performed. It highlights that the landslide is responsible for ~80% of the overall physical erosion. The soil erosion is minor and is comparable to the erosion rates measured in the neighbouring catchments. The chemical erosion leads to a dissolved flux of 7.9 kt/y (corresponding to an erosion rate of 0.02mm/y) and seems to come from the bedrock deep weathering. Nevertheless, the dissolved fluxes also appear to be linked with the particles fluxes during the monsoon. This suggests an additional weathering of the sediment during the fluvial transport. A similar approach was used on a larger scale in the Narayani catchment that drains the whole of Central Nepal. Through ADCP-based current measurements combined with deep sediment sampling, a model for sedimentary transport was used to integrate the deep sediment fluxes. The average catchment-scale erosion rate was then corrected to a value of ~1.7 mm/y, close to the long-term erosion rates. A geochemical system that combines the measurement of the δD of silicates and the concentrations of carbonates was found to be a diagnosis tracer for glacial erosion in the northern part of the catchment. The organic matter ratio was used as a tracer for soils. The temporal analysis of sediment fluxes, as well as the sediment composition and granulometry showed that only a small fraction (< 20%) of the sediment comes from glacial and soils erosion. Over the whole Central Nepal, the physical erosion seems also to be dominated by the landslides that are triggered during the monsoon. The large Narayani-Gandak alluvial fan is located at the river mouth and can be used as a record of the recent history of Central Nepal erosion. Three drillings were done in this fan to enable the study of the evolution of Himalayan weathering and erosion during the Late Pleistocene. The sedimentary deposits display a surprising stability in their geochemistry, their sources and their weathering stage for the last ~45 ky. The erosion intensity derived from cosmogenic nuclides is the only feature that seems to have risen during Holocene. However, the very recent evolution of the erosion distribution in the range is characterised by an increase (x3) of the proportion of products coming from the lower, more densely populated areas. This shows that the anthropogenic activities have had a larger impact on the erosion than the last Pleistocene-Holocene transition, especially through the rapid growth of the road network during the last decade.

La valorisation, comme granulats, des matériaux issus du recyclage du béton de démolition contribueà diminuer les surfaces dédiées au stockage des déchets et à limiter le recours systématique auxressources naturelles. L’emploi de fines recyclées à partir de béton de déconstruction s’inscrit danscette démarche et permet par ailleurs, quand la fine est utilisée en substitution partielle du cimentlors de la fabrication de nouveaux matériaux cimentaires, de réduire l’impact sur l’environnement deces matériaux.Cet usage conduit à mettre en présence dans la pâte à l’état frais du ciment anhydre et du cimenthydraté, ce qui pose la question de l’impact de cette situation sur le matériau. Pour y répondre enpartie, les travaux de recherche présentés dans cette thèse ont pour objectifs principaux d’étudier leprocessus d’hydratation d’une phase anhydre en présence d’autres phases hydratées, et d’analyserl’influence des conditions thermo-hydriques de conservation (HR et T°) sur les cinétiquesd’hydratation des matériaux cimentaires.Pour ce faire, une campagne expérimentale a été menée sur des mortiers et leurs pâtes de cimentéquivalentes fabriqués en remplaçant une partie de leur ciment Portland par une fine issue durecyclage d’une pâte de ciment durcie et bien hydratée. Un suivi au cours du temps des teneurs enPortlandite, de la porosité totale, de la résistance à la compression ainsi que de la résistance à lacarbonatation accélérée des matériaux a été réalisé. Les résultats obtenus montrent qu’il est possiblede fabriquer des mortiers en substituant le ciment par une fine obtenue uniquement par concassageet broyage d’une pâte de ciment durcie. Cependant, l’augmentation du taux de substitution massiquedu ciment par la fine recyclée s’accompagne d’une altération des propriétés et performances desmortiers. Les résultats du suivi d’hydratation couplés aux résultats d’analyse de la microstructure ontmontré que l’effet des conditions thermo-hydriques de conservation sur les cinétiques d’hydratationdes différentes pâtes de ciment dépend de leurs propriétés intrinsèques (microstructure). Celapourrait expliquer l’absence de consensus dans la littérature sur la valeur de l’humidité relativeambiante conduisant à l’arrêt de l’hydratation.En parallèle à l’étude expérimentale, une étude numérique de l’influence des conditions thermohydriquesde conservation sur l’hydratation des pâtes de ciment a été menée. Pour les besoins del’étude, une réadaptation du code de calcul utilisé, CEMHYD3D, a été nécessaire. Les résultatsobtenus montrent que, lors de l’hydratation, la Portlandite initialement présente dans le matériau(apportée par la fine recyclée) se dissout au contact de l’eau alors que la phase encore anhydre enproduit. Cette étude a également permis de conforter les résultats expérimentaux quant à l’influencede l’humidité relative ambiante sur l’hydratation. / The use, as aggregates, of recycled materials from demolished concrete contributes to limit landfill and the systematic use of natural resources. Using recycled fines from the deconstruction concrete is an extension of this approach. When used as a partial substitution for cement in cementitious materials, it may also be a solution to reduce the environmental impact of these materials.This specific use induces the presence of anhydrous cement particles and hydrated cement phases in the fresh material. This raises the question whether and how it can impact the hydration process. With the aim to answer, at least partially, to this question, the thesis presents a study of the hydration process of an anhydrous phase in the presence of other hydrated phases, and analyzes the influence of the conservation conditions (RH and T°) on the hydration kinetics of cementitious materials.An experimental campaign was conducted on mortars and their equivalent cement pastes designed by replacing a part of their Portland cement by a recycled cement paste fine. The monitoring of the Portlandite content, the total porosity, the compressive strength and the accelerated carbonation of the materials was achieved. The obtained results show that it is possible to design mortars by substituting their cement by a fine obtained only from crushing and grinding of a hardened cement paste. However, increasing the substitution ratio of the cement by the recycled fine was find to be accompanied by a deterioration of the mortars properties and performances. The results of the hydration monitoring coupled to investigations of the microstructure showed that the effect of conservation conditions on the hydration kinetics of the different cement pastes depends on their intrinsic properties (microstructure). This could explain the lack of consensus in the literature on the drying conditions under which hydration kinetics are strongly affected.In parallel to the experimental study, a numerical study of the influence of the conservation conditions on the hydration of cement pastes was conducted. Readjustments of the parameters of the used code (CEMHYD3D) were necessary. The obtained results show that, during hydration, the Portlandite originally present in the material (provided by the recycled fine) dissolves in contact with water, while the anhydrous phase produces new Portlandite. This study consolidated moreover the experimental results on the influence of the ambient relative humidity on hydration.

La littérature des dernières décennies regorge de références concernant les bienfaits des acides gras oméga 3, tels que l’EPA (C20:5 n-3) et le DHA (C22:6 n-3) qui jouent un rôle essentiel dans la prévention de nombreuses pathologies comme les maladies neurodégénératives (type Alzheimer). Les sources majeures d’EPA et DHA sont celles d’origine marine. C’est dans ce contexte que cette étude a choisi de s’intéresser aux phospholipides provenant de têtes de saumon. L’objectif était de les extraire, de purifier la phosphatidylcholine (PC) issue du mélange de lipides et d’en déterminer ses propriétés d’auto-assemblage en bicouches. Une approche expérimentale par la caractérisation physico-chimique de ce PC a été complétée par une étude théorique du même composé en utilisant les techniques de simulation par dynamique moléculaire qui a permis une caractérisation à l’échelle moléculaire des bicouches lipidiques. La caractérisation a permis d’aboutir au profil détaillé de la composition du mélange PC saumon, d’élaborer le diagramme de phase PC –eau, de déterminer les propriétés d’empaquetage d’hydratation de ce lipide. Les paramètres choisis pour l’étude en dynamique moléculaire ont permis de reproduire de manière fidèle les résultats expérimentaux, validant ainsi le modèle et les conditions de simulations déterminés au préalable. La caractérisation des propriétés structurales de la PC de saumon sous forme de multicouches a permis d’approfondir la compréhension des mécanismes d’interactions à l’échelle moléculaire existant entre les lipides insaturés eux-mêmes. / The literature of recent decades is replete with references regarding the benefits of omega 3 fatty acids such as EPA (C20:5 n-3) and DHA (C22:6 n-3) which play an essential role in preventing many diseases such as neurodegenerative diseases (Alzheimer's type). The major sources of EPA and DHA are those of marine origin. It is within this context that this study chose to deal with phospholipids from salmon heads. The objective was to extract, purify phosphatidylcholine (PC) derived from the mixture of lipids and determine its properties of self-assembly into bilayers. An experimental approach by the physicochemical characterization of this PC was supplemented by a theoretical study of the same compound using the techniques of molecular dynamics simulation that allowed a molecular-scale characterization of lipid bilayers. The characterization resulted in detailed profile of the mixture composition of salmon PC, to draw up the phase diagram of PC-water, to determine the packing and hydration properties of this lipid. The parameters chosen for the study of molecular dynamics have faithfully reproduced the experimental results, thus validating the model and simulation conditions determined in advance. The characterization of structural properties of the PC as a multilayer salmon has deepened the understanding of interaction mechanisms at the molecular level between unsaturated lipids themselves.

Lors du forage des puits d'hydrocarbure, une pâte de ciment est coulée dans l'espace annulaire entre le cuvelage en acier et les formations géologiques traversées. Pompée à l'état liquide, cette pâte de ciment fait sa prise le long du puits sous différentes conditions de température et de pression. La gaine de ciment ainsi mise en place a pour principales fonctions de promouvoir l'étanchéité pour protéger le casing contre la corrosion, de fournir le support mécanique pour assurer la stabilité du puits et d'isoler les différents fluides dans les couches traversées. Au cours de sa vie dans le puits, depuis le forage à la complétion et de la production à l'abandon, la gaine de ciment est soumise à différentes sollicitations mécaniques et thermiques qui peuvent l'endommager et altérer ses principales fonctions. La réponse de la pâte de ciment soumis à ces sollicitations dépend non seulement des conditions d'hydratation mais aussi de l'histoire des chargements précédemment appliqués. La prédiction du comportement de la gaine de ciment doit donc se faire à l'aide d'une modélisation numérique qui nécessite une loi de comportement pour la pâte de ciment. Le but de cette thèse est d'établir une loi de comportement de la pâte de ciment en cours d'hydratation pendant le jeune-âge (les 144 premières heures). Pour ce faire, des essais calorimétriques, de mesures de vitesse des ondes et des essais œdométriques ont été réalisés sur une pâte de ciment pétrolier classe G (w/c = 0,44) en cours de prise. Les conditions d'hydratation explorées vont de 7 à 30°C pour les températures et de 0,3 à 45MPa pour les pressions. Les résultats expérimentaux ont montré que les déformations volumiques de la pâte de ciment dues à son hydratation (retrait macroscopique) sont considérablement influencées par la contrainte sous laquelle la pâte de ciment s'hydrate. Plus la contrainte d'hydratation est élevée, plus élevé est le retrait macroscopique à 144 heures. Inversement, les déformations irréversibles dues à un cycle de chargement mécanique à cet âge sont moins importantes pour les contraintes plus élevées. Les résultats ont également montrés qu'au cours de la prise du ciment, il existe un temps critique à partir duquel l'application des cycles de chargement mécanique crée des déformations résiduelles dans la pâte de ciment. Ce temps critique arrive à un degré d'hydratation relativement constant, compris entre 0,18 et 0,20. Le modèle « Boundary Nucleation and Growth » a été utilisé pour étudier la dépendance de ce temps critique à la pression et à la température. Pour la modélisation du retrait macroscopique et de la réponse contrainte – déformation de la pâte de ciment, un modèle élasto-plastique chemo-poro-mécanique couplé, prenant en compte la désaturation du milieu, a été développé. Ce modèle utilise une surface de charge fermée de type Cam-Clay et une loi plastique associée. La loi d'écrouissage dépend des déformations volumiques plastiques et du degré d'hydratation. Les paramètres du modèle ont été évalués pour simuler le retrait macroscopique de la pâte de ciment hydratée sous différentes contraintes et températures. A un degré d'hydratation donnée, le modèle permet également de simuler la réponse contrainte-déformation due à un chargement mécanique / When drilling oil & gas well, cement slurry is pumped between the casing and the rock formation. This cement slurry sets at different conditions of temperature and pressure. The role of this cement sheath is to provide zonal isolation of different fluid along the well, to protect the casing against corrosion and to provide mechanical support. During the life of the well, from drilling to completion, production and P&A (plug and abandonment), the cement sheath is submitted to various mechanical and thermal loading that can potentially damage its properties and alter its performance. The behavior of cement paste submitted to theses solicitations depends both on the hydration condition and the loadings previously applied on the cement paste. The prediction of cement sheath behavior should be done by numerical modeling, which needs a constitutive law for cement paste. The purpose of the present work is to establish a constitutive law of cement paste during its hydration at early age (first 144 hours). The approach is based on combined calorimetric, wave velocities and oedometric tests on an oil-well class G cement paste with water-to-cement ratio equals 0.44. The hydration conditions explored are 7 to 30°C for temperature and 0.3 to 45MPa for pressure. The experimental results showed that the volumetric strain due to cement hydration (macroscopic shrinkage) depends considerably on the hydration pressure. At 144 hours of hydration, the macroscopic shrinkage increases with the hydration pressure increase. But, the residual strain due to application of mechanical cycle at this age is less for cement hydrated under higher pressure. The experimental results revealed that during the hydration there is a critical time after which, the application of mechanical loading can potentially induce residual strain in cement paste. This time is reached at constant hydration degree between 0.18 and 0.20. The Boundary Nucleation and Growth model was used to model the pressure and temperature dependence of this critical time. A coupled elasto-plastic chemo-poro-mechanical model is developed to simulate the macroscopic shrinkage of cement paste hydrated at different conditions of temperature and pressure. A modified Cam-Clay type yield surface with associate flow rule is used. The hardening law depends both on the degree of hydration and on the plastic volumetric strain. At constant degree of hydration, the developed model permits to simulate the stress – strain behavior of cement paste due to the mechanical loading

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study concentrates on the use of micro particles of limestone (CMV) and nano scale calcium carbonate (Np-CaCO3) in Portland cement (OPC) substitution in order to evaluate the influence in hydration reactions, microstructural morphology, mechanical properties and the durability of cement pastes and mortar. Specimens where characterized by X-ray diffraction, scanning electron microscopy, uniaxial compression, micro hardness and thermo gravimetric analysis. Atypical morphologies of calcium silicate hydrate (C-S-H) were observed in the pastes in the presence of high amount of Np-CaCO3. The results indicate that the Np-CaCO3 is reactive; accelerating early age C-S-H formation. Based on the morphological and mechanical properties, a synergetic effect was observed by the combined addition of CMV with low amounts of Np-CaCO3. Compressive strength results of the mortars are compatible with the standard requisite of the American Society of Testing Materials (ASTM). The durability of the mortars was evaluated by expositional aging methods in natural and laboratory environment for 6 months. The mechanical properties and durability of the composite cement mortars are competitive with results obtained by the reference mortars. By overall analysis of the results, it was concluded that OPC substitution of 10-30 wt.% CMV, when combined with controlled amount of Np-CaCO3 prove viable. / A presente pesquisa se concentra no uso de calcário mineral micrométrico (CMV) e nanopartículas de carbonato de cálcio (Np-CaCO3) na substituição de cimento Portland (OPC), visando avaliar a influência nas reações de hidratação, morfologia, microestrutura, propriedades mecânicas e durabilidade de pastas e argamassas de cimento. Os corpos de prova foram caracterizados por difração de raios X, microscopia eletrônica de varredura, ensaios de compressão, microdureza e análise termogravimétrica. Nas pastas foram observadas morfologias atípicas de silicato de cálcio hidratado (C-S-H) na presença de altos teores de Np-CaCO3. Os resultados indicam que as Np-CaCO3 atuam como reativos acelerando a formação do C-S-H nas primeiras idades. Em base das propriedades morfológicas e mecânicas, foi observado um efeito sinérgico quando combinados baixos teores Np-CaCO3 com CMV. Os valores de resistência a compressão das argamassas são compatíveis com os valores padrão das normas da Sociedade Americana de Testes e Materiais (ASTM). As argamassas envelhecidas em ambiente natural e laboratório por até 6 meses de exposição mostraram propriedades mecânicas e durabilidade comparáveis com resultados obtidos para argamassas feitas com cimentos de referência. Foi viável a substituição de OPC, mesmo para altos teores de carbonatos (10-35%), em especial quando combinados com teores controlados de Np-CaCO3.

The present work had as objective to study the hydration process of grains and its possible enhancement using the ultrasound technology. For that, it was studied the hydration kinetics of different grains (Andean lupin, Adzuki beans, sorghum grains and corn kernels) correlating the morphology with mathematical models and the mass transfer mechanisms. Moreover, the effect of the soaking water temperature and the grain initial moisture content were studied to complement the description of this process. The ultrasound application was studied for improving the hydration process, describing the possible mechanisms (direct and indirect effects) that improve the mass transfer process. Therefore, it was established the way by how water enters in the studied grains, demonstrating that the water transfer into the grains is a complex phenomenon and takes place not only due to diffusional mechanisms, but also by capillarity. In addition, suitable mathematical models were proposed and used to explain the processes, describing their parameters according to the grains morphology and the mass transfer mechanisms. Further, it was determined how ultrasound enhances the mass transfer and in which conditions the direct (inertial flow and sponge effect) and the indirect effects (micro channels formation by acoustic cavitation) take place in the process, maximizing the effect of this technology. Finally, it was demonstrated that the ultrasound technology enhanced the hydration process for corn kernels, reducing significantly the process time in approximately 35 %, without modifying the thermal, structural and rheological properties of their starch. In conclusion, the present work improved the description of the grain hydration phenomenon and proved that the ultrasound technology can be used to enhance this process without changing its main industrial component. It is highlighted that the obtained results are thus high desirable for both the industrial and academic point of view. / O presente trabalho teve como objetivo estudar o processo de hidratação de grãos e sua possível melhora usando a tecnologia do ultrassom. Estudou-se a cinética de hidratação de diferentes grãos (tremoço andino, feijão Adzuki, grãos de sorgo e grãos de milho) correlacionando a morfologia com modelos matemáticos e os mecanismos de transferência de massa. Também foi estudado o efeito da temperatura e o conteúdo de umidade inicial do grão para complementar a descrição deste processo. Estudou-se a aplicação do ultrassom no processo de hidratação descrevendo-se os possíveis mecanismos (efeito diretos e indiretos) que melhoram a transferência de massa. Como resultado, foi estabelecida a forma como a água entra nos grãos estudados, demostrando que a transferência de água dentro dos grãos é um fenômeno complexo e que acontece por difusão e capilaridade. Foram propostos e utilizados modelos matemáticos apropriados para explicar os processos, descrevendo os parâmetros de acordo com a morfologia dos grãos e os mecanismos de transferência de massa. Ainda, determinou-se como o ultrassom melhora a transferência de massa e em que condições do processo acontecem os efeitos diretos (fluxo inercial e efeito esponja) e efeitos indiretos (formação de micro canais pela cavitação acústica), maximizando o efeito dessa tecnologia. Finalmente, demonstrou-se que a tecnologia do ultrassom melhora o processo de hidratação de grãos de milho, diminuindo significativamente o tempo do processo em cerca de 35 % sem alterar as propriedades térmicas, reológicas e estruturais do seu amido. Como conclusão, o presente trabalho melhorou a descrição de como os grãos são hidratados, demonstrando que o ultrassom pode ser usado para melhorar o processo de hidratação de grãos sem alterar os seus principais produtos industriais. Ressalta-se que os resultados obtidos são desejáveis tanto do ponto de vista acadêmico quanto industrial.

A soja é uma leguminosa com alto valor nutricional, devido principalmente a seu alto conteúdo protéico. Dentre a cultura de grãos, a soja caracteriza-se como a mais importante do país, o que representa um incentivo ainda maior para o consumo desse alimento. Porém, este alimento ainda sofre restrições por parte dos consumidores ocidentais, devido, principalmente a seu odor e sabor característicos, conhecidos como beany flavor, que é proporcionado pela ação da enzima lipoxigenase. A ação catalítica exercida por esse tipo de isoenzima sobre ácidos graxos poliinsaturados, ácido linolênico e linoléico, dos grãos de soja é um dos principais fatores responsáveis pelo aparecimento dos compostos carbonílicos, os quais causam o sabor desagradável em grãos. Para melhorar as características organolépticas da soja, pesquisadores desenvolveram novas cultivares, sem a presença da lipoxigenase. O objetivo deste trabalho foi avaliar diferenças físicas, químicas e sensoriais entre as cultivares de soja com lipoxigenase e sem lipoxigenase (cultivar BRS 232 e BRS 257, da Embrapa, respectivamente) e analisar as possíveis alterações promovidas por diferentes doses de radiação (0, 4 e 8 kGy) nos grãos de soja crus e cozidos. As análises físicas realizadas foram o tempo de cocção e o tempo de hidratação dos grãos. As análises químicas realizadas foram a composição centesimal, digestibilidade da proteína, fatores antinutricionais, teor de isoflavonas e capacidade antioxidante (DPPH e ABTS). Os aspectos sensoriais foram determinados por análise sensorial realizada aplicando-se métodos analíticos de diferenciação para seleção de provadores, e método descritivo para determinar a qualidade da soja. Ao final, foi realizada análise estatística fatorial 3x2x2 (doses de irradiação x cultivares x tratamentos) para análise, comparação e discussão dos resultados obtidos. Os resultados mostraram diferenças nas medidas das análises físicas com a irradiação e com as diferentes cultivares. Além disso, as diferentes cultivares apresentaram diferenças na composição centesimal, digestibilidade, teor de fenólicos, isoflavonas e inibidor de tripsina. A cocção promoveu diferença em todos os componentes estudados, com exceção da digestibilidade protéica dos grãos. Por outro lado, a irradiação afetou os compostos antinutricionais, a digestibilidade protéica e o teor de isoflavonas agliconas. Os dados da análise sensorial mostraram que o sabor e a textura das amostras não diferiram entre os cultivares e não foram afetadas pela irradiação. / The soybean is a vegetable with high nutricional value, mainly due to its high protein content. Among the culture of grains, the soybeam is the most important in Brazil, what represents a greater incentive for the consumption of this food. However, a great claim of occidental consumer is its characteristic odor and flavor, known as beany flavor, which is provided by the action of lipoxigenase enzyme. The catalytic action exerted by this type of isoenzime on pollyunsaturated fatty acids, linolenic and linoleic acid of the soy grains, is one of the main factors responsible for the appearance of the carbonyl compounds, which cause the unpleasant flavor in grains. To enhance the organoleptic characteristics of soybeans, researchers have developed new cultivars, without the presence of lipoxigenase. The objective of this study was tof evaluate physical, chemical and sensorial differences between the two soy cultivar, with and without lipoxygenases (cultivars BRS 232 and BRS 257, of Embrapa, respectively) and to analyze the possible changes promoted by different radiation doses (0, 4 and 8 kGy) in raw and cooked soybean grains. The physical analyses were: time of cooking and hydration of the grains. The chemical analyses were: centesimal composition, protein digestibility, antinutritional factors, isoflavone content and antioxidant capacity (DPPH and ABTS). The sensory aspects were determined by sensorial analysis performed by appling analytical methods of differentiation for selection of panelists, and descriptive method to determine the quality of the soybean. At the end, factorial statistical analysis was performed 3x2x2 (irradiation doses X cultivars x treatment) for analysis, comparison and discussion of the obtained results. The results showed differences in physical analyses with the irradiation and between the two cultivars. Besides, the cultivars presented differences in the centesimal composition, digestibility fenolic content, isoflavone content and tripsin inhibitor. Cooking promoted difference in all the studied components, except for the proteic digestibility of the grains. On the other hand, the irradiation affected the antinutritional contents, the proteic digestibility and the content of aglicone isoflavones. Data from sensory analysis showed that the taste and the texture of the samples didn\'t differ between the cultivars and were not affected by the irradiation.

The aim of the doctoral thesis was to study advanced fluorescence techniques and its use in colloids or hyaluronan-surfactant systems and hydrogels based on hyaluronan, respectively. Steady-state and time-resolved fluorescence were used to study excited state proton transfer fluroescen probes in hyaluronan-surfactant systems to asses the influence of hyaluronan hydration to its interactions with oppositely charged surfactants. Firstly, different excited state proton transfer fluorescence probes were discussed to choose the most suitable candidate for next research. The influence of hyaluronan on inner environment of micells was determined based on the sensitivity of excited state proton transfer of chosen fluorescence probe 1-naphtol and, based on above mentioned experiments, the structure of hyaluronan hydration shell was discussed. The next part of doctoral thesis was focused on fluorescence lifetime correlation spectroscopy and on the development of method of nanorheology. Measured correlation functions were transformed to mean square displacement with developed MATLAB script. Firstly, the fluorescence method was compared with well described methods such as videomicrorheology and dynamic light scattering to asses the reliability of fluorescence correlation spectroscopy in microrheology. Secondly, nanorheology method was developed and its use in passive nanorheology of hyaluronan hydrogels was discussed. Based on mentioned experiments, the fluorescence correlation spectroscopy microrheology and nanorheology methods were optimized to use the methods in hydrogel research.

This work focuses on the hydration of four calcium aluminate phases – C3A, C12A7, CA and CA2. Above all, the influence of particle size and method of preparation on hydration behaviour were studied. Influence of these factors on hydration products were also investigated. Calcium aluminates were prepared by solid state synthesis and amorphous citrate method. Both methods were described in detail. The particle size was determined by laser diffraction. Isothermic calorimetry was used to investigate the process of hydration. Hydration products were identified by X-ray diffraction analysis and simultaneous thermogravimetric and differential thermal analysis.

DIPLOMA THESIS IS FOCUSED ON THE PREPARATION AND PROPERTIE OF BELITE CLINKER. IT IS BASED ON THE STUDY OF SCIENTIFIC ARTICLES DEALING WITH THE ABOVE MENTIONED TOPIC AS WELL AS THE ANALYSIS OF THE BRNO THD INSTITUTE´S RESEARCH RESULTS. AS PART OF MY EXPERIMENTAL WORK, A PROPOSAL OF THE COMPOSITION OF RAW MEAL TO EXTRACT BELITE CLINKER IN THE PRESENCE OF POTASSIUMS CARBONATE AND SULPHATE WAS MADE TO MODIFY RAW MEAL. THE PURPOSE OF MODIFYING RAW MEAL IS A POTENTIAL INCREASE IN BELITE CLINKER REACTIVITY. FURTHER THE EXTRACTION OF BYPASS DUST FROM A LOCAL CEMENT PLANT WAS CONDUCTED. THE EVALUATION OF THIS RESEARCH WAS MADE BY THE X-RAY DIFFRACTION (XRD) ANALYSIS METHOD.