[pt] O entendimento do fenômeno de deposição de parafina em linhas submarinas de produção e transporte de petróleo é importante para a construção de modelos de previsão que auxiliem no projeto e operação destas linhas. No presente trabalho, foram realizados experimentos controlados em escala de laboratório com o objetivo de obter informações sobre alguns aspectos relevantes da deposição de parafina. Para isso, foi utilizada uma seção de testes anular, com condições de contorno bem controladas, operando com um fluido de testes com propriedades bem conhecidas, e apresentando uma distinção marcada entre a composição do solvente e aquela das parafinas. A seção de testes era equipada com uma sonda de temperatura de pequenas dimensões acoplada a um micrômetro, o que permitiu a medição de perfis de temperatura dentro do depósito para condições de escoamento. A sonda também possibilitou a obtenção da temperatura da interface depósito-líquido ao longo da formação do depósito. Os testes incluíram a variação do número de Reynolds do escoamento anular, da temperatura da parede fria, e da taxa de resfriamento da parede. Uma câmera de vídeo de alta taxa de aquisição de imagens acoplada a lentes de aproximação foi utilizada para determinar a posição da sonda de temperatura em relação à interface do depósito. Os resultados mostraram que a temperatura da interface se mantém estável em um valor intermediário entre a TIAC (Temperatura Inicial de Aparecimento de Cristais) e a TDC (Temperatura de Desaparecimento de Cristais), desde quando a deposição de inicia até quando depósito atinge sua espessura de regime permanente. A câmera de vídeo forneceu imagens originais sobre a formação dos depósitos, notadamente sobre uma região acima do depósito em formação onde cristais de parafina são carregados pelo escoamento, sem que um número significativo destes cristais depositasse ou fosse aprisionado no depósito. As imagens revelaram também que estes cristais não são oriundos de cristais arrancados do depósito em posições a montante no início do duto, mas têm origem no seio do fluido adjacente à interface do depósito. A sonda de temperatura foi também utilizada na medição da temperatura nesta região de líquido acima da interface do depósito onde, por um período de tempo, cristais de parafina escoavam. / [en] The proper understanding of the wax deposition phenomena in subsea oil pipelines is relevant to the development of more accurate models to aid in the design and operation of these lines. In the present work, laboratory-scale experiments under well-controlled conditions were conducted to study some relevant aspects of wax deposition. To this end, an annular deposition test section was employed, using a test fluid with known properties, and displaying a marked distinction between the solvent and the wax chemical components. The test section was equipped with a temperature probe of small dimensions, driven by a micrometer head. This probe allowed the measurement of temperature profiles within the wax deposit, under flowing conditions, and also the temperature of the deposit-liquid interface as the deposit was formed. The tests encompassed the variation of the annular flow Reynolds number, the cold wall temperature and the wall cooling rate. A high-frame-rate video camera coupled to magnifying lenses was used to provide images of the temperature probe and of the deposit interface. The results showed that that temperature of the interface remains stable in an intermediate value between the WAT (Wax Appearance Temperature) and the WDT (Wax Disappearance Temperature), since the first moments of the deposition until the deposit reaches its steady state configuration. The video camera captured original images on the deposit formation, especially on a region above the deposit where wax crystals are carried by the flow for a period of time. Only an insignificant number of carried crystals were observed to deposit over the immobile interface, or to be captured at the interface. The images also revealed that the carried crystals do not originate from crystals sloughed from upstream positions in the annular duct. The temperature probe was also employed to measure the temperature of the liquid region above the deposit interface where the crystals existed for a period of time.

Restoration of stream channels have become a common way of trying to restore both the channels and the ecosystems that earlier have been channelized mainly to facilitate the movement of timber. According to previous studies a lot of the restoration has been performed without a sufficiently detailed plan and with too little focus on how the landscape interplay with the restoration, which makes the potential to learn from possible mistakes minimal. In this study, a hydrological analysis of Hjuken river was done to examine if remote data through an analysis using GIS could be used for identifying three different process domains (lake, slow-flowing reaches and rapids), and if it is possible to determine which process domain it is by examining three different variables: channel slope, surficial geology and the geomorphologic characteristics in the landscape. Based on the statistical treatment and the analysis of the data, the result shows a significant difference between every process domain and variable except for the channel slope when it comes to slow-flowing reaches and rapids. This tells us that all the variables that has been analysed could be a crucial factor in most of the cases. However, the result does not seem reliable compared to previous studies. The conclusion of the study is that the error from the identification of the process domains is from the orthophotos. Remote data is too weak to use as the only source for this kind of analysis. However, the definition of process domains is probably more diffuse than today’s description. There needs to be more studies on each process domain, it is probably not enough with three different types, either there should be subclasses for each process domain or even more process domains.

Cette thèse traite de la modélisation des réacteurs chimiques par la « modélisation compartimentale », qui consiste à diviser le système en un réseau d’une dizaine à quelques centaines de volumes interconnectés, appelés compartiments. La structure du réseau est déduite à partir d’informations provenant d’expériences de traçage, d’informations techniques sur le réacteur chimique, de simulations de mécanique des fluides numérique et des objectifs de la modélisation. Cette méthode procure un bon compromis entre temps de calcul et finesse des résultats. Quand ils sont correctement menés, les modèles à compartiments donnent des prédictions similaires, en termes de réactions chimiques, à ceux issus des simulations de mécanique des fluides numérique réactive avec un temps de calcul plus court et une représentation physique plus concrète du comportement du réacteur. Chaque étude issue de la littérature est consacrée à un réacteur spécifique avec une approche particulière qui ne peut pas être directement transposée sur un autre réacteur. L’objectif de cette thèse est d’apporter une contribution au développement d’une méthodologie la plus générale possible et de développer un outil de génération automatique et de résolution du système d’équations différentielles qui doit être résolu. Dans le premier chapitre, un état de l’art est réalisé, définissant le champ d’application de notre méthode, dans le but d’identifier les méthodes de découpage les plus pertinentes et les différentes méthodes pour calculer les échanges entre les compartiments. Dans un second chapitre, une méthode générale pour de la modélisation compartimentale est développée. Une approche polyvalente est proposée, consistant à découper le réacteur en tranches identiques. Le calcul des échanges entre compartiments, dus à la convection et la turbulence, est présenté en détail, avec la description des trois méthodes de calcul des échanges turbulents. Une interface a été développée permettant de construire n’importe quel réseau de compartiments. À partir de cette interface, les équations sont écrites et automatiquement résolues. La méthode est appliquée dans un troisième chapitre sur un cas défavorable au découpage en tranches. Cela a permis de tester les limites de cette approche. En particulier, deux points ont été étudiés : (1) l’applicabilité du découpage en tranches identiques et (2) la comparaison entre les méthodes de calcul des échanges turbulents. Le premier test a prouvé la robustesse de l’approche par division mais le second test n’a pas permis d’établir si une méthode de calcul est meilleure qu’une autre. Finalement, la méthode a été valorisée et transférée en implémentant les algorithmes développés dans un logiciel commercial. Ce logiciel permet de simuler la dispersion d’espèces réactives et non réactives (traceurs), dans un modèle contenant plusieurs centaines de compartiments organisés en tranches identiques / This PhD deals with modelling of chemical reactors with the “compartmental modelling” approach, which consists in dividing the system into a network from a dozen to several hundreds of interconnected volumes, called compartments. The structure of the network is deduced from tracer experiments, technical information about the chemical reactor and computational fluid dynamics flow simulations. This method provides a good compromise between computation time and results accuracy. When they are properly set-up, compartmental models give similar predictions, in terms of chemical reactions, as those of CFD simulations with a shorter calculation time and a more concrete representation of the reactor behavior. Every study from the literature is devoted to a specific reactor with a particular approach that cannot be straightforwardly transposed to other reactors. The aim of this PhD is to provide a contribution to the development of the most general possible methodology and to develop an automatic tool of generation and resolution of the differential equations system which must be solved. In the first chapter, a state of the art is proposed, defining the field of application of our method, in order to identify the most relevant division methods and the different methods to calculate the exchange between compartments. In the second chapter, a general methodology for compartmental modelling is developed. A versatile approach is proposed, consisting in dividing the reactor in identical slices. The calculation of exchange between compartments, both due to convection and turbulence, is presented in detail, with the description of three calculation methods for turbulent exchange. An interface has been developed, allowing to build any network of compartments. From this interface, the equations are written and solved automatically. The methodology is applied in the third chapter to an unfavorable case for slice cutting. This has allowed to test the limit of this approach. In particular, two points have been studied: (1) the applicability of division into identical slices and (2) the comparison between the turbulent exchange calculation methods. The first test has proved the robustness of the division approach but the second test has not allowed to establish whether one calculation method is better than another. Finally, the methodology has been promoted and transferred by implementing the developed algorithms within a commercial software. This software allows to simulate the dispersion of reactive and non-reactive (tracers) species, in model containing hundreds of compartments organized in identical slices

This diploma thesis deals with the description of the chemistry of stagnant and flowing surface waters in selected part of the Velká podkrušnohorská dump and subsequent statistical processing of data. Sulfates are dominating element of the stagnant and flowing water, which form sulfato complexes with elements Ca2 + and Mg2+. The values CHSKCr in stagnat water are half compared to flowing water (upper and lower reaches). Higher values CHSKCr are result of biochemical, chemical and biological processes in the aquatic environment in stagnant water.

The goal of submitted thesis is to perform a computer simulation of bubble creation in T-channel. In the first section of the paper, the theoretical applications of microfluidic bubble, micromachines and droplet formation are described. In the second part of the text, author uses cross flowing method for simulation od bubble creation. Furthermore, several settings in computer simulation software Fluent are mentioned. In addition, the influence of velocity at the T-channel inlet on surface tension and on bubble length is presented.

In this master’s thesis, a preliminary thermodynamic calculation of the turbine is made. Then, the design and location of the vacuum breaker is devised for this turbine. The aim of the master’s thesis is to calculate a time needed to break the vacuum, ie to determine how long it takes to reach the atmospheric pressure inside the turbine and add-on devices. To verify and improve the accuracy of the calculation there are data measured on real projects used.

Flodpärlmusslan (Margaritana margaritifera) är en starkt hotad mussla som är beroende av öring (Salmo trutta) för sin larvutveckling. Musslan är negativt påverkad av dagens användning av vattendrag och omgivande mark då de har höga krav på sin omgivning. Denna undersökning tittar på hur bottensubstrat, tillgång till värdfiskars habitat och kantzonernas sammansättning påverkar musslornas rekrytering. För detta användes biotopkarteringar, vilka relaterades till musslans rekrytering. Resultatet visade att hög förekomst av ståndplatser för värdfisken, strömmande vatten och buskskiktet på land var positivt för rekryteringen av flodpärlmusslan. Det visade sig däremot att det inte var någon skillnad i bottensubstratets sammansättning eller i antalet diken mellan vattendrag med och utan rekrytering. Slutsatsen för denna undersökning är att det behövs fördjupade studier på mindre skala och i akvarieexperiment med fokus på hur värdfiskens habitat, hydrologin och kantzonens utseende påverkar musslans rekrytering. / The freshwater pearl mussel (Margaritana margaritifera) is a highly endangered mussel that depends on trout (Salmo trutta) for its larval development. The mussels are negatively affected by the current use of watercourses and surrounding land as they have high demands on their surroundings. This study looks at how bottom substrates, access to host fish habitats and the composition of ecotone affect mussel recruitment. For this biotope mapping was used, which was related to the mussel's recruitment. The results showed that the high prevalence of sites for host fish, flowing water and the shrub layer on land was positive for the recruitment of freshwater pearl mussels. It turned out, however, that there was no difference in the composition of the bottom substrate or in the number of ditches between watercourses with and without recruitment. The conclusion of this study is that in-depth studies on a smaller scale and in aquarium experiments are needed with a focus on how the host fish's habitat, hydrology and the appearance of the edge zone affect the mussel's recruitment.

This Master’s thesis is focused on design and optimalization of intake and exhaust system of the C20XE engine. It is four-cylinder gasoline engine with stroke volume of two litres, which was produced by car company Opel. This engine is determined for Opel Astra F automobile, that is build for racing. For optimalization of dimension parameters there is used a Lotus Engine simulation software, which simulates one-dimension gas flowing in manifold. 3D CAD models are made in Pro ENGINNER software.

The Pitted Ware culture on Gotland presents a multitude of material that allow archeologists to re-construct and visit the socio-economic structure of a middle-neolithic settlement in the Baltic sea. I will be analyzing the archaeological material in accordance to the ocean, and to what we can interpret as ritual and cosmological variables at the site through ritual theory, and with a method of comparative analogy and research. How maritime aspects of divinity manifested itself to the PWC, ontology and belief system could perhaps reveal how the cognitive, collective mind of one culture evolved and made connections to otherworldly entities. Often in the form of ancestral worship, which will be one of the main issues that will be analyzed and discussed throughout, in addition to mortuary ritual. / Den Gropkeramiska kulturen på Gotland demonstrerar ett extensivt material som tillåter arkeologer att rekonstruera och besöka den socioekonomiska strukturen hos en mellanneolitisk kultur i Östersjön. Jag kommer att analysera materialet i relation till havet, och försöka utgöra havets rituella och kosmologiska kopplingar till lokalen genom ritualteori och en analogisk, komparativ metod. Sättet som maritima aspekter av gudomlighet manifesterade sig inom den Gropkeramiska kulturen på Gotland, dess ontologi och trossystem kan möjligtvis avslöja hur det kollektiva, kognitiva sinnet hos en kultur utvecklades och skapade kontakter till utomvärldsliga ting. Ofta i form av förfädersdyrkan, som tillsammans med begravningsritualer kommer vara ett centralt ämne genom hela uppsatsen.

[pt] Deposição de parafina em linhas de produção e transporte de petróleo é um problema relevante para a indústria. Perdas significativas de produção e com operações de limpeza, desobstrução ou substituição de linhas ocorrem devido à formação de depósitos das frações mais pesadas do petróleo sobre a superfície interna dos dutos operando nas águas frias típicas da produção em águas profundas. A formação de depósitos de parafina nas superfícies dos dutos pode ocorrer quando o petróleo quente proveniente dos poços é resfriado abaixo de uma temperatura crítica onde há o início da formação de cristais de parafina. Esta temperatura é denominada TIAC – temperatura inicial de aparecimento de cristais. A previsão da deposição de parafina através de modelos de simulação é uma ferramenta fundamental para o projeto e operação das linhas de forma economia e segura. Diversos modelos de deposição de parafina vêm sendo desenvolvidos ao longo dos anos, incorporando diferente propostas para o fenômeno de deposição de parafina. No presente trabalho o fenômeno da deposição de parafina foi estudado utilizando um fluido modelo escoado em uma seção de testes anular construída de modo a oferecer condições de contorno e iniciais bem definidas. Acesso óptico ao interior da seção de testes permitiu a obtenção de imagens de qualidade da formação de cristais de parafina. Uma sonda de temperatura de pequenas dimensões foi utilizada para obter informações originais sobre perfis de temperatura no depósito durante sua formação. Também foram obtidas informações sobre a evolução temporal da temperatura da interface do depósito para diferentes vazões e taxas de resfriamento. A formação transitória de nuvens de cristais sobre a interface do depósito e carregados pelo escoamento foi registrada em imagens de alta frequência. A temperatura no interior dessas nuvens foi registrada pela sonda de temperatura. Os resultados mostraram que a interface do depósito evolui a partir da TIAC da solução medida por microscopia, atingindo rapidamente uma temperatura constante de valor intermediário entre a TIAC e a temperatura termodinâmica de mudança de fase da solução. Esta informação contraria umas das hipóteses fundamentais do mecanismo de difusão molecular, base dos modelos acadêmicos e industriais mais utilizados. A presença de cristais de parafina em solução em temperaturas acima da TIAC indica que, localmente, o valor da TIAC difere daquele obtida por microscopia, e que as taxas locais de resfriamento são inferiores às impostas junto à parede fria, permitindo a formação dos cristais acima dos depósitos. Os dados experimentais de qualidade obtidos no presente trabalho são uma importante referência para o teste de modelos de simulação do processo de deposição. / [en] Wax deposition in petroleum production and transportation lines is one of the most relevant problems faced by the industry in order to assure the flow of oil and gas at the designed economical rates. Significant losses occur due to decreased production, line replacements and maintenance costs associated with cleaning operations. Wax deposit formation on the inner wall of the pipes might occur when the warm oil from the well loses heat to the cold environment, typical of deep water production operations, and its temperature reaches a critical value at which wax crystal formation occurs. This critical temperature is the WAT, wax appearance temperature. The prediction of wax deposit formation by simulation models is of fundamental importance for the proper design and operation of petroleum lines. Several wax deposition models have been developed and employed over the years, incorporating different wax deposition mechanisms. In the present work, the wax deposition phenomenon was studied employing a model fluid flowing through an annular test section, built to offer simple and well-defined boundary and initial conditions for the deposition process. Optical access to the interior of the test section allowed for the registration of images of the wax deposit formation. A miniature temperature probe was designed and employed to obtain original information on the temperature profiles within the deposit as it was formed. Also, the probe registered the transient evolution of the deposit interface temperature for different flow rates and cooling rates. The transient formation of a cloud of wax crystals over the deposit interface and carried by the flow was registered by a high frame rate camera. The temperature within this cloud was measured by the temperature probe. The results have shown that the deposit interface temperature evolves from a value equal to the WAT of the fluid measured by microscopy, rapidly reaching a constant value which is intermediate between the WAT and the solution thermodynamic phase change temperature. This information contradicts one of the key assumptions included in the molecular diffusion deposition mechanism, and widely employed in academic and industrial simulation models. Wax deposition in petroleum production and transportation lines is one of the most relevant problems faced by the industry in order to assure the flow of oil and gas at the designed economical rates. Significant losses occur due to decreased production, line replacements and maintenance costs associated with cleaning operations. Wax deposit formation on the inner wall of the pipes might occur when the warm oil from the well loses heat to the cold environment, typical of deep water production operations, and its temperature reaches a critical value at which wax crystal formation occurs. This critical temperature is the WAT, wax appearance temperature. The prediction of wax deposit formation by simulation models is of fundamental importance for the proper design and operation of petroleum lines. Several wax deposition models have been developed and employed over the years, incorporating different wax deposition mechanisms. In the present work, the wax deposition phenomenon was studied employing a model fluid flowing through an annular test section, built to offer simple and well-defined boundary and initial conditions for the deposition process. Optical access to the interior of the test section allowed for the registration of images of the wax deposit formation. A miniature temperature probe was designed and employed to obtain original information on the temperature profiles within the deposit as it was formed. Also, the probe registered the transient evolution of the deposit interface temperature for different flow rates and cooling rates. The transient formation of a cloud of wax crystals over the deposit interface and carried by the flow was registered by a high frame rate camera. The temperature within this cloud was measured by the temperature probe. The results have shown that the deposit interface temperature evolves from a value equal to the WAT of the fluid measured by microscopy, rapidly reaching a constant value which is intermediate between the WAT and the solution thermodynamic phase change temperature. This information contradicts one of the key assumptions included in the molecular diffusion deposition mechanism, and widely employed in academic and industrial simulation models.