Dissertations / Theses on the topic 'Gtl2'

A descoberta de uma nova província petrolífera, conhecida como pré-sal, localizada no litoral brasileiro, representa um novo marco na produção de petróleo mundial. Dentre os vários desafios encontrados para exploração e produção dessa região, a presença de CO2 em grandes concentrações nos fluidos de alguns desses reservatórios tem sido um dos desafios de maior relevância para as empresas que exploram e produzem nessa área (FORMIGLI, 2007). Uma forma alternativa de sequestro do CO2 retirado do gás natural é a sua utilização como matéria prima ou co-alimentação para a síntese de produtos químicos, em especial aqueles com grande demanda de mercado. Um dos produtos que podem ser obtidos indiretamente a partir do CO2 é o petróleo sintético, produzido pelo processo conhecido como Gas-to-Liquids, ou GTL. Neste trabalho foi analisada a viabilidade técnica, econômica e potencial de captura de CO2, da produção de petróleo sintético, pelo processo GTL, offshore, a partir de dióxido de carbono (CO2) e metano (CH4), presentes na corrente de rejeito do tratamento do gás processado em uma plataforma de produção de petróleo e gás, através das reformas seca e a vapor, seguida da síntese Fischer-Tropsch. A partir de dados de literatura e com uso de simulador comercial de processos, a simulação do processo foi desenvolvida e diferentes alternativas para reaproveitamento das correntes residuais do processo foram analisadas, incluindo o reciclo e a queima dos efluentes combustíveis, assim como foram aplicadas técnicas de integração energética, otimização e análise econômica de processos. Os resultados indicaram que o processo, mássica e energeticamente integrado, na condição de menor emissão de CO2 e maior retorno financeiro, produziu petróleo sintético de forma técnica e economicamente viável. Os resultados indicaram ainda que o processo GTL, com as tecnologias utilizadas, não é indicado como método de captura de CO2 devido o fato de a geração desse componente para a produção de petróleo sintético ser duas vezes maior que a quantidade alimentada.
The discovery of a new oil province known as pre-salt, located in the Brazilian coast, represents a new frontier in the world\'s oil production. Among other challenges involved in the exploration and production in that region, the CO2 concentration at high levels in the fluids of some of those reservoirs has been the most relevant challenge for the companies that explore and produce in that area (FORMIGLI, 2007). An alternative to sequestering the CO2 extracted from natural gas is using it as a supply of raw material or as an input to the synthesis of chemical products, especially those with great market demand. One of the products that can be obtained indirectly from CO2 is synthetic fuel, produced by the process known as Gas-to- Liquids, or GTL. In this work the technical, economical and potential feasibility of CO2 capture is analyzed, as well as the production of synthetic fuel using the GTL process, offshore, from carbon dioxide (CO2) and methane (CH4), found in the waste chain of the gas treatment in an oil and gas production platform, through dry and steam reforming, followed by Fischer-Tropsch synthesis. Thus, based on literature data and on the use of a commercial process simulator, the simulation of the suggested process was developed and different alternatives to the reutilization of the waste chains were analyzed, including the recycling and burning of some effluent streams. Techniques of energetic integration, optimization and economic analysis of process have also been applied. The results indicated that the process, mass and energy integrated in the condition of lower CO2 emissions and greater financial return, produced synthetic oil in a technically and economically feasible way. The results also indicated that the GTL process, with the technologies used, is not suitable as a method for CO2 capture due to the fact that the generation of this component for the production of synthetic oil is two times greater than the amount fed.

This dissertation intends to provide new tuning techniques for several simple cubic equations of state (EOS) to improve their accuracy in calculating fluid phase equilibrium. It also provides graphical tools to predict some phase equilibrium phenomena from activity coefficient models. Finally, it presents simulation results for a new gas-to-liquids process. Saturation Properties for Fluids: By deriving a new identity linking the heat of vaporization for pure components to the EOS, we are able to find new expressions for the two constants a & b in the EOS. These new expressions then allow tuning of both constants a and b to experimental saturation properties at subcritical temperatures. These new tuning procedures prove effective to the point where the simpler Redlich-Kwong EOS provides better results with our procedure than does the usually superior Peng-Robinson EOS with conventional procedures. Activity Coefficient Models: This dissertation shows the flexibility of four activity coefficient models in the prediction of three fluid phase equilibrium phenomena. From these models we successfully developed new graphs that allow one to identify the presence of any of the three phenomena by visual inspection without performing a complex calculation as seen in current texts. Remote Natural Gas: This dissertation presents simulation results of a new gas-to-liquids process which converts natural gas to liquid transportation fuels. Based on the assumption of adiabatic reactions, our simulation results show that methane conversion increases with higher reaction temperature and longer residence times. Hydrogen can both inhibit methane decomposition and reduce coke formation. The rich components in the natural gas are found to decompose very fast and they have a vast quenching effect on the whole reactions. Recycling of unreacted methane also increases overall methane conversion. Finally, our simulator provides very close prediction of the experimental results from a pilot plant. Thus, we conclude that the simulation work is basically successful in fulfilling the goal of this research.

Phanerochaete chrysosporium est un champignon forestier faisant partie des organismes saprophytes capables de recycler la matière organique morte. Grâce à l'excrétion de nombreuses enzymes de dégradation, en particulier des lignine peroxydases, il est capable de décomposer la matière végétale dont la lignine, un polymère complexe de composés phénoliques très résistant. L'élimination de la lignine permet la libération des autres composants du bois tels que la cellulose et l'hémicellulose qui peuvent être utilisés dans l'industrie papetière ou pour la production de bioéthanol de deuxième génération. La structure des intermédiaires et produits de dégradation de la lignine est souvent proche de celle denombreux polluants, d'où l'intérêt biotechnologique de P. chrysosporium dans les processus de bioremédiation. Cependant, les systèmes de dégradation engendrent des composés plus ou moins toxiques pour le champignon et contre lesquels il doit faire face. C'est pourquoi il possède un système de détoxication impliquant des enzymes telles que les cytochrome P450 monooxygénases ou encore les glutathion transférases (GST). Les Ure2p forment une classe de GST étendue chez Phanerochaete et d'autres basidiomycètes saprophytes. Leur étude par des approches phylogénétiques, biochimiques, structurales et transcriptomiques a permis de mieux comprendre les mécanismes d'évolution que peut subir une classe d'enzymes potentiellement soumises à une forte pression de sélection
Phanerochaete chrysosporium is a forest fungus being part of saprophytic organisms able to recycle dead organic matter. Thanks to the excretion of numerous wood decaying enzymes, and especially lignin peroxidases, this fungus is able to break down plant material including lignin, a complex polymer of phenolic compounds. Lignin removal allows the release of other wood components such as cellulose and hemicellulose, which can be further used in paper industry or to produce second generation bioethanol. The structure of intermediates and products from lignin decomposition is close to that of numerous pollutants making P. chrysosporium biotechnologically interesting for bioremediation purposes. Moreover, the fungus has to deal with more or less toxic compounds created by degradation mechanisms. It thus presents a detoxification pathway involving enzymes including cytochrome P450 monooxygenases and glutathione transferases (GST). Ure2p enzymes belong to an extended GST class in Phanerochaete genus as well as in other saprophytic basidiomycetes. Their study based on phylogenetic, biochemical, structural and transcriptomic approaches provides a better understanding of evolution mechanisms of a class of enzymes potentially subject to strong selection selection pressure

Les cils sont des organites très conservés au cours de l'évolution des eucaryotes et présents à la surface de presque tous les types cellulaires. Ils sont constitués d'une structure microtubulaire, l'axonème, entourée d'une membrane en continuité avec la membrane plasmique. Ils sont nucléés par un corps basal, centriole ancré à la surface cellulaire. Grâce aux nombreux récepteurs qu'ils concentrent à leur membrane, tous les cils sont des senseurs de leur environnement. Ils peuvent aussi être motiles et assurer, par leur battement coordonné, le déplacement relatif de la cellule et du fluide environnant. Tandis que cil et structure centriolaire, hérités du premier eucaryote, ont été perdus par certains champignons et par les plantes supérieures, certains gènes codant des protéines ciliaires et centriolaires sont pourtant retrouvés dans le génome de ces espèces. Cette conservation de protéines sans l'organite suggère soit que ces protéines interviennent dans un même processus moléculaire utilisé dans plusieurs organites, soit qu'elles jouent des rôles dans des processus moléculaires distincts via leur interaction avec différents types de partenaires.J'ai choisi d'étudier l'une de ces protéines ciliaires et centriolaires, Bug22p, hautement conservée en séquence protéique entre l'homme et la paramécie, mais également présente chez les plantes supérieures. J'ai mené cette étude principalement sur la paramécie, système modèle pour la biogénèse des corps basaux et des cils, mais aussi sur des cellules de mammifère et de végétaux supérieurs. Si Bug22p est impliquée dans la détermination du battement ciliaire chez la paramécie, elle se localise également dans des cils immotiles de cellules de mammifère suggérant que son activité ciliaire n'est pas réduite à cette seule fonction. Des expériences d'inactivation génique suggèrent par ailleurs un lien entre l'activité de Bug22p et la polyglycylation. Sa surexpression dans les cellules de mammifère en culture entraîne l'apparition d'extensions cellulaires et une augmentation des réseaux de tubulines acétylées probablement associées à une stabilisation des microtubules. L'ensemble de mes résultats suggère donc un rôle de Bug22p dans la régulation de modifications post-traductionnelles. En plus d'être présente dans les structures ciliaires, Bug22p se localise aussi bien dans les noyaux de la paramécie que dans ceux des cellules humaines et des plantes supérieures Arabidopsis et Nicotiana. Ces observations ouvrent un nouveau champ d'études. En effet, si l'on sait que les tubulines ciliaires sont soumises à différentes modifications post-traductionnelles telles que polyglycylation ou acétylation, ce type de modifications touchent également des protéines nucléaires régulant ainsi le trafic de protéines nucléaires ou l'expression génique. Nous pouvons donc avancer l'hypothèse selon laquelle Bug22p agirait sur la régulation de ces modifications dans le cil et dans le noyau. Il serait donc intéressant de caractériser les modifications post-traductionnelles chez les plantes supérieures afin de vérifier une possible implication de Bug22p dans leur régulation et donc comprendre les raisons de sa conservation chez les végétaux.

COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
O Presente trabalho tem como objetivo analisar a viabilidade econômica de uma planta XTL usando a teoria das Opções Reais. Esta metodologia é a mais adequada para avaliar a capacidade que este tipo de projeto dispões de trocar de input e/ou output, ou seja, eleger a cesta que maximiza o resultado final, de acordo com cada cenário. Essa política ótica permite avaliar a construção de uma planta com flexibilidades, com o investimento ocorrendo em um ambiente de incerteza, onde os preços (fatores de incerteza) serão considerados estocáticos e seguirão um Movimento de Reversão à Média. Os cálculos numéricos serão feitos através da simulação de Monte Carlo. A tecnologia, designada XTL, está dividida em duas etapas: um processo de gaseificação seguido de um processo GTL (gás-to- liquid). A gaseificação permite transformar sólidos, líquidos e gases em gás de síntese, que será usado como input do GTL. Já o GTL possibilita transformar o gás de síntese em líquidos de alta qualidade, tais como nafta, diesel, parafinas e lubrificantes. Por associação, esta dissertação faz parte de um projeto que visa aplicar a teoria de Opções Reais na avaliação de investimentos em Pesquisa e Desenvolvimento (P&D), com a finalidade de valorar e considerar as flexibilidades inerentes a este tipo de projeto.
The present work has objective to analyze the investiment of a XTL plant using the Real Options Theory. This methodology is adjusted to evaluate the capacity that this project has to changes its input and/or output, in other words, to elect the option that maximizes payoff, in accordance with each scenario, allowing to evaluate the construction of a plant with flexibilities with the investiments happening in an environment of economical and/or technical uncertainties, where the prices (uncertainty factors) are stochastic and will follow the Mean Reversion Model, calculated by the Monte Carlo Simulation. The XTL technology is divided in two stages: a gasification process followed by a GTL (gas-to-liquid) process. The gasification process allows you to transform solids, liquids and gases into synthesis gas, that will be used as input of the GTL. The GTL makes possible to transform the syntesis gas into high quality liquids, such as naphtha, diesel, paraffins and lubrificants. This work is part of a project, with the objective to apply the Real Options Theory in the evaluation of investiments in Research and Development (R&D), aiming to price and consider the flexibilities that are inherent to this project.

In the Thesis, the problem of associated petroleum gas flaring both in Russia and in the world is revealed. The analysis of associated petroleum gas utilization methods in respect to the small remote oil fields is carried out. The Thesis shows the perspective of creating low and medium power autonomous installations for energy supply to the oil facilities in the remote areas with poorly developed energy infrastructure by processing associated petroleum gas in small-scale GTL technology unit. Taking into account specifics of small remote oil fields, GTL technology scheme was chosen among existing types and its material balance wascalculated. The schemes of both associated petroleum gas utilization and power production on site in the small remote fields were suggested and compared to each other from economical and environmental perspectives. Furthermore, the economic effect from themini-GTL technology introduction into the schemes was defined.
I avhandlingen uppenbaras problemet med tillhörande petroleumsgaser både i Ryssland och i världen. Analysen av tillhörande oljeutnyttjande metoder för de små avlägsna oljefälten utförs. Avhandlingen visar perspektivet på att skapa låga och medelkraftiga autonoma installationer för energiförsörjning till oljeanläggningarna i de avlägsna områdena med dåligt utvecklad energiinfrastruktur genom att bearbeta tillhörande oljegas i småskaliga GTL-teknologienheten. Med tanke på särdrag hos små avlägsna oljefält valdes GTLteknikprogrammet bland befintliga typer och dess materialbalans beräknades. Systemen för både tillhörande oljeutnyttjande och kraftproduktion på plats i de små avlägsna fälten föreslogs och jämfördes med varandra från ekonomiska och miljömässiga perspektiv. Vidare definierades den ekonomiska effekten från mini-GTLteknikintroduktionen i systemen.

COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
O objetivo da presente dissertação é capturar o valor da opção de parada temporária que uma planta GTL oferece em cenários econômicos desfavoráveis para mantê-la operando. Desta forma, o autor considera que a metodologia das opções reais é a mais indicada para avaliar tal flexibilidade, sendo assim, o objetivo principal deste estudo é a análise da opção de parar temporariamente através da utilização do processo estocástico (Movimento geométrico Browniano)e a correlação de Cholesky entre cada input e os outputs da planta. O autor acredita que os resultados desta dissertação podem auxiliar os gestores que enxergam flexibilidades em seus projetos a antecipar prejuízos prolongados em cenários desfavoráveis para manter uma planta funcionando.
The objective of this dissertation is to capture the value of the option to temporarily stop that a GTL plant offers in unfavorable economic scenarios to keep it operating. Thus the author believes that the methodology of real options is the best placed to assess such flexibility, and thus the main objective of this study is the analysis of the option to temporarily stop using the stochastic process (geometric Brownian Motion) and the correlation Cholesky between each input and outputs of the plant. The author believes that the results of this dissertion can assist the managers who see flexibilities in its projects to anticipate damages drawn out in favorable scenes to keep a plant functioning.

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Tendo em vista o desenvolvimento de uma abordagem diferente da convencional adotada para a síntese do metanol, justificado pelo crescimento do mercado de consumo e produção dessa matéria prima, foi desenvolvido um processo de síntese via gás de síntese em reator de mistura. Nesse processo, o leito catalítico foi posicionado em um cesto no interior do reator, que girava em rotações pré-determinadas, entre 200 – 800 RPM, onde foram conduzidas avaliações cinéticas. Operando-se com um catalisador comercial (KATALCOJM 51-8), nas condições definidas por meio de avaliações termodinâmicas, de equilíbrio líquido-vapor e fluidodinâmica, foi determinada a região de operação do sistema, estabelecida em pressões na faixa de 20,0 – 30,0 atm e temperaturas de 473 – 573 K, com base em um planejamento fatorial 3². Foram conduzidas, nessas condições, avaliações dos efeitos de resistência externa, por influência da velocidade de rotação do cesto catalítico, via quantificação do número de Biot. Avaliações do regime de operação nessas condições também indicaram o estabelecimento do regime químico de operação, com domínio da reação catalítica, via determinação do módulo de Thiele modificado. Em operação descontínua com uso do catalisador comercial, produziu-se metanol com conversão média de CO e H2, rendimento e seletividade médios a metanol iguais a 86%, 96%, 39% e 70%, respectivamente a 30,0 atm e 523 K. Foram formulados catalisadores baseados em Cu e Zn sobre γ-alumina, preparados pelo método de impregnação úmida e caracterizados via análises de difração de raios-x, espectrofotometria de absorção atômica e propriedades texturais (área superficial, volume de poros, volume de microporos e raio médio de poros). Em operação descontínua, esses catalisadores tiveram suas atividades catalíticas avaliadas, alcançando conversão de CO, rendimento e seletividade médios a metanol iguais a 32,5%, 25% e 85%, respectivamente. Foram desenvolvidos modelos cinéticos para predição do comportamento dos reagentes e produtos no processo, em termos do modelo de Langmuir-Hinshelwood-Hougen-Watson, a partir dos quais foi possível a quantificação dos parâmetros cinéticos e de equilíbrio. Esses modelos foram estendidos à predição do comportamento das operações em regime contínuo, conduzidas para o catalisador comercial e aqueles formulados.

La tolérance au froid est un caractère complexe lié à des modifications au niveau écophysiologique et métabolique. L'objectif de ce travail est d'identifier les zones chromosomiques clés impliquées dans la tolérance aux basses températures à partir d'une étude sur une population de backcross avancé obtenue à partir d'un parent tropical d'altitude dans le fond génétique d'un parent corné. Une approche sans a priori repose sur la mise en évidence des zones chromosomiques impliquées dans les variations de biomasse en réponse au froid ainsi que sur les origines de ces variations: mise en place des feuilles, photosynthèse et métabolismes carboné et azoté. Une approche avec a priori est basée sur l'hypothèse que le glutathion, molécule antioxydante, serait une molécule clé dans la tolérance aux basses températures. Grâce à ces deux approches, nous concluons que la photosynthèse semble jouer un rôle primordial mais que le rôle du glutathion reste limité dans notre contexte génétique et pour les scénarios climatiques testés
Cold tolerance is a complex mechanism linked to ecophysiological and physiological changes. The aim of this work was to identify key chromosomal regions involved in low temperature tolerance. This work was based on a population resulting from the advanced back-cross with a highland tropical inbred within a flint background. A first approach was based on the detection of chromosomal regions involved in biomass changes in response to cold and their origin: canopy development, photosynthesis, carbon and nitrogen metabolisms. A second approach was based on the hypothesis that an antioxidant, the glutathione, bas a key role in low temperature tolerance. Combining these two approaches, we conclude that photosynthesis seems to play a key rote when the glutathione one is limited in our genetic background and for the climatic conditions tested

The nuclear industry has undergone a revival in recent years, which has been more commonly termed the nuclear “renaissance”. This renaissance period has brought renewed interest to the commercial nuclear industry as well as to peripheral or related industries, particularly in the areas of research and development. Some of the most common research topics include the integration of nuclear and process technologies, or more specifically the use of nuclear heat energy in process plants. Gas–to–liquids (GTL) technology, although often referred to as an unconventional fossil fuel technology, is a mature technology and successful commercial applications in the state of Qatar are evidence of that. Likewise, thermal desalination processes such as multi stage flash (MSF) and multiple effect distillation (MED) are also very mature technologies that have been in commercial operation for many decades. Both GTL and desalination processes may be regarded as energy intensive processes that demand large amounts of thermal energy, which is typically provided by the combustion of fossil fuels. The use of fossil fuels as a primary energy source, however, has a number of drawbacks: unstable and/or rapidly increasing prices, negative environmental impact as well as concerns over long term sustainability. Nuclear energy is far more attractive from a sustainability perspective and also produces negligible carbon dioxide (CO2) emissions. By utilising nuclear heat energy either directly or through waste heat in a secondary circuit, process plants become more energy efficient whilst also emitting less green house gases. The proposed process design is an integrated nuclear GTL facility: the primary focus is the integration of heat energy in a typical GTL complex. The secondary focus is the use of nuclear energy to drive electricity and potable water production. A typical GTL facility herein refers to the type investigated and proposed in a recent feasibility study conducted by Sasol Technology and Sasol Chevron Holdings Limited in 2006, which is property of Sasol Chevron Holdings Limited and Sasol Chevron Holdings Qatar Limited, as part of the Sasol Chevron Integrated GTL project comprising gas and GTL plants. The proposed integrated facility is a large industrial complex and Qatar was chosen as a suitable geographic location for the study for a number of reasons: * Established GTL industry, which is supported by the government as a means of monetizing their natural gas resources. * Extensive natural gas reserves fed from the world’s largest non–associated gas field * An industrial city, such as Raf Laffan, that contains well established logistical and engineering infrastructure to support a large industrial complex. * Socio–economic considerations that warrant the development of additional utilities generation capacity in Qatar. * Favourable political climate for the introduction of nuclear energy in the region. In the proposed design only a handful of units in the typical GTL complex were identified for heat integration: synthesis gas generation (reforming), hydrogen production unit (reforming) and the process superheaters. The focus area of the GTL complex was then upstream of the Low Temperature Fischer Tropsch (LTFT) reaction units and there were no opportunities for heat integration identified in the downstream product work up (PWU) or refinery units. The process was modelled as a nuclear steam methane reforming (SMR) process, with nuclear heat providing the required endothermic reaction energy for the reforming process. The helium exit temperature from the reforming process was 781.50oC, which meant that the helium could also be used to superheat the complex high pressure (HP) steam. The superheated HP steam was then used as feed to the reformers themselves and to drive a back end Rankine power cycle. A final stage, backpressure turbine then provided low pressure (LP) steam to drive MSF desalination units. Approximately 40 percent of the total available nuclear thermal energy was used in the reforming and superheater units. In the helium Brayton power cycle a significant amount of electricity was generated whilst also providing low temperature waste heat that was utilized for MED desalination units. The proposed integrated design thus combined three technologies that together produced large quantities of their respective products. The integrated nuclear GTL design also required the introduction of a CO2 shift reactor downstream of the reforming units to correct the synthesis gas (Syngas) ratio fed to the LTFT reactors. The CO2 makeup stream was assumed to be imported from offsite. This shift reactor unit was certainly a departure from the conventional GTL process layout and represented a significant CO2 credit opportunity, particularly in the context of a large industrial facility such as that at Ras Laffan. The conventional GTL design also utilizes autothermal reforming technology that requires oxygen feed to the units, while the nuclear SMR process does not require oxygen. Thus another benefit associated with nuclear GTL integration would be the omission of the air seperation units (ASU), which ordinarily require large amounts of energy to drive the unit air compressors. A pressure swing adsorption (PSA) unit and CO2 wash unit were also included upstream of the FT reactors, providing both clean Syngas at the required Syngas ratio as well as a clean, high purity stream of hydrogen to be used in the PWU units. An economic analysis was performed to gauge the realistic viability of the technical proposal. In this analysis simple return on investment (ROI) calculations were performed to provide net present value (NPV) and internal rate of return (IRR) indications. A constant discount rate of 21.25% was used for all economic calculations. The various technologies were also analysed as stand–alone facilities and then together as an integrated facility. The major drivers or levers in each of the respective industries were used as bases for low, high and reference economic analysis. The base case typical GTL complex returned very favourable values with an IRR of 68%. The integrated facility also retuned favourable ROI indictors with an IRR of 42%. In the context of an integrated nuclear GTL facility, the nuclear portion alone was not economically viable as most of the energy was used for process heat rather than power generation. The inclusion of C02 credit revenues only marginally improved the economics of the nuclear portion of the facility, but obviously contributed positively to the overall facility ROI indicators. At a CO2 credit value of 90.62 $/ton the nuclear portion of the integrated facility would become economically justifiable in its own right. However, it may be argued that such a high CO2 credit value is highly unlikely in the short to medium term future. The major technical benefits of a nuclear integrated facility include improved carbon efficiency and measurable CO2 emissions reduction. The typical (base case) GTL facility, however, has an attractive business case without the integration of the nuclear and desalination technologies. A decision to invest in such a large, integrated facility would thus depend heavily on local socio–economic and political factors. The key driver in GTL economics, and hence the proposed integrated design as well, is the product pricing and natural gas/crude oil price differential. This is the main reason for presenting low, high and reference growth cases in the economic analysis. Despite lower NPV and IRR indicators than the GTL base case, the integrated design still represents an attractive investment. The comprehensive facility is also an excellent means to monetize gas resources and provide utilities to a fast growing nation.
Thesis (M.Sc. Engineering Sciences (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2012.

COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PETRÓLEO BRASILEIRO S. A.
O objetivos desta dissertação é fazer uma análise de investimentos usando a teoria das Opções Reais de uma planta GTL. Está análise é a mais indicada, pois se verificam várias flexibilidades nesta planta em relação aos inputs (pode ser usado mais de um produto como matéria- prima) e em relação aos outputs (existem várias combinações possíveis de produção). Torna-se de grande importância neste caso saber calcular o valor destas opções e verificar se vale a pena ou não a construção de uma planta que possa usar como matéria prima mais de um produto e/ou que possa produzir mais de uma possível combinação de produção. A construção de uma planta que possua a possibilidade de trocar de insumo e/ou trocar a combinação de produção só será viável caso o valor criado pela flexibilidade seja maior do que o custo necessário para implementá-la (investimento adicional e custos operacionais extras). Sendo assim, o objetivo desta dissertação é calcular até quanto a Petrobras estaria disposta a pagar para ter uma planta que possua a opção de swicth use dos inputs e/ou outputs, o valor que ela teria que investir para usufruir desta flexibilidade, e através da diferença entre estes valores verificar se vale a pena ou não a construção da planta com flexibilidade de input e/ou output.
The objective of this dissertation is to do a analysis of investiment using the real option theory for the plant GTL. This analysis is the best because there are many flexibilities in this plant in relation the inputs (the plant can operate with several inputs) and in relation the outputs (there are many possible combination of production). In this case is very important to know how to calculate the value of these options and to verify if it is worthwhile or not the construction of a plant that could use two inputs and/or is able to procuce several possible combinations of production. The construction of the plant that change the input abd /or can changer the production combination is viable if the value created by flexibility is large than the necessary cost to implement its (additional investiment and extra operational costs). So, the objective of this dissertation is to calculate until hen Petrobras would be avaible to pay in order to have a plant that has the option of swicth use of inputs and/or outputs, the value it would have to invest to use this flexibility, and through the difference between these values verify if is worthwhile or not the construction of the plant with the flexibility of input and/or output.

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The current natural gas production of 52 Mm3d-1 and the large projects for its expansion has been setting new boundaries for the Brazilian industry of oil and gas. So far, one of the biggest challenges regards to the logistics for gas transportation from offshore fields. Therefore, the transformation of natural gas into gasoline, diesel and/or olefins via Fischer-Tropsch synthesis would be an alternative to this matter. In this work, the production of hydrocarbons by Fischer-Tropsch synthesis in a slurry reactor was investigated and a perovskite-type catalyst (LayCu0,4Fe0,6O3 ? d) was used with y varying from 0 to 1 on a molar basis. In addition, Nb2O5 support was also applied in order to observe the selectivity of the produced hydrocarbons by the Fischer-Tropsch process. It is shown that the hydrogen conversion was influenced by the support as well as the different phases of the samples. The kinetic results for the CO2 production suffered great influence with the introduction of the Nb2O5 support throughout the series of samples studied. The catalysts allowed obtaining welldefined cuts of hydrocarbons in the range of C1-C6 and C17-C28, and these results were clearly influenced by the support and the lanthanum content. The higher olefin/paraffin ratio obtained was 1.8 when using a non-supported perovskite with y equal to 0.8. This would indicate the suitability of using this material for the production of olefins
A produ??o atual de 52 milh?es m?dia-1 de g?s natural e os grandes projetos para esta expans?o vem estabelecendo novas fronteiras para a ind?stria nacional de petr?leo e g?s, sendo um dos maiores desafios a log?stica para o transporte do g?s oriundo de campos offshore. Uma alternativa seria usar o g?s natural para a produ??o de gasolina, diesel e/ou olefinas atrav?s da s?ntese de Fischer-Tropsch. No desenvolvimento deste trabalho foi investigado a produ??o de hidrocarbonetos via s?ntese de Fischer-Tropsch em um reator slurry mediante uso de catalisadores do tipo perovskita, LayCu0,4Fe0,6O3?d, onde y sofreu varia??o de 0 at? 1 em base molar. A s?ntese dos catalisadores levou em considera??o o estudo da influ?ncia do teor de lant?nio e do suporte (Nb2O5) na atividade e seletividade da rea??o de Fischer-Tropsch, objetivando a produ??o de hidrocarbonetos. As convers?es de H2 foram sensivelmente influ?nciadas pela presen?a de fases existentes em cada amostra, assim como pelo suporte. Os resultados da cin?tica de produ??o de CO2 sofreram grandes influ?ncias com a introdu??o do suporte em toda a s?rie das amostras produzidas. Os catalisadores empregados permitiram a obten??o de cortes bem definidos de hidrocarbonetos na faixa de C1-C6 e C17-C28, sendo estes resultados claramente influenciados pelo suporte e pela varia??o do teor de lant?nio. A maior rela??o olefina/parafina obtida foi de 1,8 para a perovskita com y igual a 0,8 na amostra n?o suportada, viabilizando o uso deste material na produ??o de olefinas

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A temática da presente pesquisa é a realização de mapeamento de domínios de conhecimento. A atividade de acompanhamento das construções discursivas dos diversos domínios do saber tem se mostrado útil para diferentes objetivos e tem despertado o interesse da Organização e Representação do Conhecimento para o mapeamento temático. Esta pesquisa se propõe a mapear um domínio do conhecimento e contribuir, através do caminho metodológico percorrido, com diretrizes para o mapeamento de domínios do conhecimento. Por meio das palavras-chave das comunicações orais do GT2 “Organização e Representação do Conhecimento” do ENANCIB, foi possível mapear e analisar as temáticas apresentadas neste evento, mais precisamente em suas dez últimas edições, período compreendido entre 2003 e 2013. A pesquisa teve como abordagem teórica os princípios da Organização e Representação do Conhecimento com ênfase nas formas de recortar conceitualmente um domínio e na análise do referencial teórico envolvido na construção de modelos classificatórios. Também utilizou a teoria de Análise de Domínio, que apresenta orientações de como identificar um domínio e uma comunidade discursiva. O método hipotético-dedutivo guiou a forma de pensar as questões levantadas pelo campo empírico, quanto aos objetivos, esta pesquisa caracteriza-se como exploratório descritiva, os resultados foram obtidos pela abordagem quantitativa e, também se enquadra em uma pesquisa documental. Os termos representativos do domínio ligados à sua comunidade discursiva foram organizados de forma a transparecer as temáticas mais recorrentes, visando demonstrar o estado da arte do domínio. Os dados organizados possibilitaram, em um primeiro momento, uma visão geral do domínio e, em um segundo momento, uma análise dos termos classificados no “Sistema de Classificação da Literatura de Organização do Conhecimento”. A análise permitiu obter como principais resultados: elevado índice de dispersão temática no domínio; alta concentração de pesquisas na região Sudeste do país; preferência pela pesquisa aplicada; carência de pesquisas nas temáticas que envolvem os aspectos metodológicos utilizados no domínio e nos assuntos referentes a Representação Descritiva da Informação. O caminho percorrido para obtenção destes resultados é apresentado em forma de diretrizes, organizadas em ações práticas, visando à realização de mapeamento temático de domínios do conhecimento.
The subject of this research is mapping out knowledge domains. Accompanying discursive constructions of diverse knowledge domains has proven useful for different objectives and has called the attention of Organization and Representation of Knowledge for Thematic Mapping. This research proposes mapping a knowledge domain and contributing, by way of the chosen methodology, with directives for mapping knowledge domains. Using the keywords of the papers presented for the GT2 “Organization and Representation of Knowledge” at the ENANCIB seminar made it possible to map and analyze the subject matter presented during this event, more precisely during its last 10 editions, from 2003 through 2013. The theoretical approach to this research made use of the principles of Organization and Representation of Knowledge with emphasis given to forms of conceptually delineating a domain and in analyzing the theoretical referential involved in constructing classificatory models. This approach also used the theory of Domain Analysis, presenting guides to identifying a domain and a discursive community. The hypothetical-deductive method guided the way problems were dealt with as they came up during the empirical research phase. Regarding objectives, this research may be characterized as exploratory and descriptive and results were obtained by using a quantitative approach, also pertaining to a documental research approach. The representative terms of domain tied to its discursive community were organized so that more recurrent subject matter would appear, with the aim of demonstrating the state of the art of domain. The data organized initially made a general view of the domain possible and then afterwards an analysis of the terms classified in the “Classification System for Knowledge Organization Literature”. The analysis allowed obtaining the following results: an elevated index of thematic dispersion in the domain; a high concentration of research in the Southeast region of the country; preference for applied research and a lack of research on the methodological aspects used in the domain and the Descriptive Representation of Information. The route taken in order to obtain these results was described as directives, organized into practical acts, with the aim of carrying out thematic mapping of knowledge domains.

In this thesis, the systematic plantwide procedure of Skogestad (2004) is applied to two processes; 1- Post-combustion CO2 capturing processes, 2- Natural gas to liquid hydrocarbons (GTL) plants, in order to design economically efficient control structures, which keep the processes nearoptimum when disturbances occur. Because of the large magnitude of energy consumption in both these processes, optimal operation is of great importance. The self-optimizing concept, which is the heart of the plantwide procedure is used to select the right controlled variables in different operational regions, which when they are kept constant, indirectly give the operation close to optimum. The optimal is to reconfigure the self-optimizing control loops when the process is entered into a new active constraint region, but we try to arrive at a simple/single control structure, which does not need switching, where a reasonable loss in operating economic objective function is accepted. The CO2 capturing process studied here is an amine absorption/stripping system. The chosen objective function for this process is first to minimize the energy requirement while fixed CO2 recovery of 90% is met. This leads to one unconstrained degree of freedom. Maximum gain rule is applied and a temperature close to the top of the stripper is found as the best controlled variable. Further, we introduce penalty on CO2 amount released to the atmosphere, and this results in two unconstrained degrees of freedom. CO2 recovery and a temperature close to the top of the stripper are found as the best individual controlled variables in low feedrate. In higher flue gas flowrates, stripper heat input saturates and the self-optimizing method is repeated to select the right controlled variable for the remaining degree of freedom. We validate the propose control structures using dynamic simulations, where 5 different alternatives including decentralized control loops and multivariable controller are studied. We finally achieve a simple control structure, which handles a wide range of change in throughput and keeps the process close to optimum without the need for switching the control loops or updating the controlled variables setpoints by a costly real time optimizer. The GTL process modeled in this thesis includes an auto-thermal reformer (ATR) for synthesis gas production and a slurry bubble column reactor (SBCR) for the Fischer-Tropsch (FT) reactions. The FT products distribution is determined using a well-known Anderson- Schultz- Flory (ASF) model, where carbon component in CO (consumption rate is found based on the proposed rate by Iglesia et al.) is distributed to a range of hydrocarbons. ASF is a function of chain growth probability and the chain growth is a function of H2/CO ratio. We study different scenarios for chain growth and we arrive at a suitable model for optimal operation studies. The optimal operation is considered in two modes of operation. In mode I, natural gas feedrate is assumed given and in mode II, natural gas feedrate is also a degree of freedom. After optimization, in both modes, there are three unconstrained degrees of freedom. The best individual self-optimizing controlled variables are found and since the worst-case loss value is rather notable, combination of measurements is done, which reduces the loss significantly. Mode II happens when oxygen flowrate capacity reaches the maximum and we show that operation in mode II in this case is in snowballing region where operation should be avoided. Operation at maximum oxygen flowrate capacity is where maximum practical profit can be achieved.

L’objectif de cette thèse était la mise en place de deux approches complémentaires. En premier lieu, une méta-analyse de QTL a été réalisée à partir des études publiées dans la littérature et d’études deQTL internes à Syngenta, afin de définir de façon plus précise les régions chromosomiques impliquées dans les caractères liés à la digestibilité. La cartographie physique et génétique du maïs ont été utilisés pour identifier et positionner les gènes candidates impliqués dans la qualité de l’ensilage et de tester leurs colocalisations avec les métaQTL. Au total, 37 et 57 métaQTL ont été identifiés pour les caractères de digestibilité et parois respectivement et les gènes candidats colocalisaient significativement avec les intervalles de confiance des métaQTL. Dans un second temps, une étude de génétique d’association a été réalisée dans les régions mise en évidence par la méta-analyse. Le panel utilisé est composé de 314 lignées représentant le germplasm denté et inclut des lignées publiques mais aussi des lignées du matériel élite de Syngenta. Plus de 100 amplicons ont été séquencés et analysés dans les régions d’intérêt puis testés pour leur association avec les caractères de digestibilité. Les associations entre la floraison et les séquences étudiées par Ducrocq et al. (2008) dans la région Vgt1 ont également été étudiés pour évaluer les propriétés de ce panel par rapport aux panels précédemment étudiés dans la littérature et comparer les différents logiciels utilisés en génétique d’association. Nos résultats ont confirmé l’effet de la région Vgt1 sur la précocité de floraison. Neuf associations significatives ont été mises en évidence pour la digestibilité des parois
Quality of silage corn is a trait of major interest for corn breeding in Europe. In order to increase breeding efficiency, it is important to locate precisely the loci (QTL) involved in the variation of this trait and to identify those that carry favorable alleles at these QTL. The goal of this PhD was to carry out two complementary approaches. First, a meta-analysis was performed on the QTL detected in previous studies issued from publications and Syngenta, in order to refine the chromosomal regions involved in traits related to digestibility. Maize physical map and sequence data were used to identify and position candidate genes for silage quality, and to test their colocalization with metaQTL. A total of 37 and 54 metaQTL were found for digestibility and cell wall respectively and the candidate genes colocalized significantly with the metaQTL confidence intervals. Secondly, association mapping was performed on the regions identified through meta-analysis. The panel used for the association tests was composed of 314 inbred lines representing dent European and American germplasm, including public inbred lines and elite material of Syngenta. More than 100 amplicons were analysed in the regions of interest over the whole panel and tested for their association with digestibility traits. Association between flowering time and sequences studied by Ducrocq et al. (2008) at the Vgt1 QTL region were also investigated to evaluate the properties of this panel relative to the ones previously published and to compare different association mapping software. Our results confirm the effect of the Vgt1 region. Nine significant associations were found for digestibility related traits

Gas to liquids (GTL) technology, although an attractive method for meeting liquid fuel requirements into the future, has an inherent concern regarding the environmental impact of dealing with the large amount of carbon dioxide that is generated. In this investigation, the potential to reduce this carbon dioxide footprint by utilising process heat from high temperature helium at 950oC downstream of a High Temperature Gas (cooled) Reactor (HTGR) is examined. The study compares a base case steam methane reformer (SMR) heated by the combustion of natural gas to a nuclear heated steam methane reformer heated by hot helium from one HTGR. It has been shown that it is possible to reduce the carbon dioxide footprint almost entirely for the synthesis block of a GTL facility. Process heat integration from one HTGR has the potential to reduce the carbon dioxide footprint of an SMR by approximately 42 tons per hour. The full potential of one HTGR in terms of carbon dioxide reduction for a GTL facility was also investigated. This was achieved by estimating the cogeneration potential impact on carbon dioxide emissions where the residual heat in the helium stream downstream of the reformer was used for power generation. The overall amount of carbon dioxide reduction from both the reformer and power generation facility was then quantified and an economic study was completed. The study shows that with one HTGR it would be possible to reduce the carbon dioxide emissions of a GTL facility by almost 200 t/h if nuclear process heat was used in the reformer and nuclear power generation was used instead of conventional coal based power generation. Results from the economic study show that industry would have to incur an operating cost increase of approximately R200, at current natural gas prices, to reduce their carbon dioxide emissions by one ton if nuclear energy was used as a process heat source and for power generation.
Thesis (M.Sc. Engineering Sciences (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2010.

Devido à sua natureza, o gás natural (GN) tem na distância aos pontos de consumo um obstáculo para sua utilização, a qual vai além simples queima para geração de energia ou obtenção de calor. Portanto, é importante que sejam discutidos novos métodos para distribuí-lo e transformá-lo em fontes de energia de maior valor agregado ou em matéria-prima para fabricação de produtos a serem utilizados na indústria química. Uma opção é a conversão do GN em combustíveis líquidos de pronto uso como óleo diesel, gasolina e querosene de aviação através da rota Gas-To-Liquids (GTL). O presente trabalho avalia o potencial da tecnologia GTL no contexto do crescimento da oferta de gás natural no Brasil pelos gasodutos Rota 2 e Rota 3, contextualizando o cenário brasileiro desse energético, as perspectivas futuras e o estado da tecnologia GTL com o processo Fisher-Tropsch. Para tanto, é simulado e analisado o desempenho econômico de uma planta de diesel GTL operante por 30 anos em cenários de preços de insumo e produto obtidos por projeções de reconhecimento internacional.
The usage of natural gás (NG) is related to the distance to the final customers, that is a real obstacle to its full utilization which is beyond the usage as fuel for electricity or heat generation. It is important to prospect, analyze and propose new methods for distribution and transformation of this important energy suppy to more value added products or special raw material for the chemical industry. The transformation in ready for use liquid fuels like diesel, gasoline and kerosene through the gas-to-liquid route (GTL) is one of the options. This dissertation evaluates the GTL technology in a context of the NG additional volume available through 2 new pipelines coming from offshore, Rota 2 and Rota 3 in the Brazilian context of NG current usage and its future perspectives taking advantage of this additional availability via the traditional and long term tested GTL Fischer-Tropsch (FT) technology. A GTL FT Diesel plant operating for 30 years was taken as an example considering different scenarios for NG and Oil prices retrieved from the IEA data base that is internationally considered as a consistent source of information.

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A tecnologia de produção de combustíveis sintéticos iniciou seu desenvolvimento a partir de 1919, na Alemanha, tendo o carvão mineral como insumo para a gaseificação. Com o passar dos anos novos insumos foram utilizados, como a biomassa e o gás natural, cada um com rotas tecnológicas próprias. Com o uso do gás natural esta rota tecnológica é conhecida como Gas-To- Liquids (GTL) sendo uma transformação química que gera faixas de hidrocarbonetos líquidos e estáveis à temperatura e pressão ambientes. Este processo tem como etapa principal etapa à reação de Fischer Tropsch (FT), pois transforma gás síntese resultante da reforma do gás natural em hidrocarbonetos líquidos que ao serem refinados tornamse importantes produtos para indústria petroquímica, de transporte e áreas afins. Essa transformação pode ser realizada no próprio local de produção do gás, evitando investimentos e problemas ambientais na construção de gasodutos. No Brasil, o gás natural apresenta crescente incremento da sua produção, e forte aumento das suas reservas, como por exemplo, a descoberta do pré-sal e o gás natural presente pode estar tanto associado quanto não-associado ao petróleo. Devido às estruturas de plataformas normalmente se localizarem em áreas remotas, torna-se custoso o aproveitamento desse gás que é liberado pela produção do óleo, sendo o mesmo queimado ou ventado. Devido às restrições estabelecidas pela legislação ambiental, a queima do gás natural nas plataformas de produção passa a ser problemática e crítica. Este trabalho teve como objetivo desenvolver e avaliar por meio de simulação computacional uma planta de GTL na produção de hidrocarbonetos líquidos via a reação de FT e utilizá-lo na otimização do processo, na busca por um processo com maior capacidade produtiva e com menores gastos energéticos, gerando um melhor aproveitamento do gás natural, produzindo materiais com maior valor agregado. Foram utilizados os softwares de simulação MATLAB® e HYSYS®, que permitiram a analise de resultados satisfatórios para a conversão e distribuição de hidrocarbonetos gerados em comparação com o descrito pela literatura. A qualidade dos hidrocarbonetos gerados foi analisada pela avaliação do diesel obtido.

Aquesta tesi se centra en l’estudi de les possibles glicosiltransferases de Micoplasma genitalium involucrades en la síntesi de glicolípids. Aquests compostos formen part de la membrana plasmàtica del microorganisme, únic envolcall que el protegeix del seu entorn ja que no disposa de paret cel•lular. La hipòtesi sobre la qual s’ha desenvolupat el treball és la possibilitat que aquests glicolípids i els enzims encarregats de la seva producció, les glicosiltransferases, siguin essencials per a la viabilitat del micoplasma i per tant, la seva inhibició sigui una forma d’eradicar les infeccions causades pel patògen. De les tres seqüències classificades com a glicosiltrasferases en el genoma de Mycoplasma genitalium, mg025, mg060 i mg517, s’ha determinat que mg025 és l’únic dels tres gens que no és essencial per al bacteri, tot i que s’ha observat que els tres s’expressen tant a la fase exponencial com a la fase estacionària del seu creixement. La funció de mg025 i mg060 és encara desconeguda, mentre que mg517 és la glicosiltransferasa encarregada de la síntesi dels dos principals glicolípids del micoplasma, el monoglicosildiacilglicerol (MGlcDG) i el diglicosildiacilglicerol (DGlcDG). En aquesta tesi s’ha desenvolupat un protocol d’expressió per a la glicosiltransferasa codificada per mg517, anomenada GT-MG517, el qual fa ús d’una coexpressió amb xaperones i solubilitza la proteïna amb detergents, glicerol i una elevada força iònica. Aquesta metodologia ha estat necessària ja que GT-MG517 és una proteïna associada a membrana i la seva expressió recombinant en E.coli presenta dificultats. La proteïna s’ha purificat mitjançant cromatografia d’afinitat per Ni, tot i que el grau de puresa assolit no ha estat suficient per a intentar la seva cristal•lització. Les diverses proves realitzades usant cromatografia d’exclusió molecular han permès determinar que GT-MG517 forma oligòmers d’alt pes molecular. A partir de la proteïna purificada s’ha realitzat un estudi cinètic de la seva doble activitat glicosildiacilglicerolsintasa. D’aquest estudi s’extreu que GT-MG517 pot transferir un sucre, Glc o Gal, a una molècula principalment hidrofòbica, com és el DOG, i a una molècula molt més hidrofílica, com el MGlcDG. Ambdós compostos però posseeixen un alcohol primari sobre el qual té lloc la transferència creant l’enllaç (16). Amb qualsevol dels substrats acceptors provats, l’enzim presenta activitats específiques superiors si el substrat donador és UDP-Gal. L’acceptor preferit de GT-MG517 és el lípid DOG, però la glicosiltransferasa és capaç d’elongar, ja sigui amb una Glc o amb una Gal, glicolípids com el MGlcDG i el MGDEG, preferint en aquest cas el compost amb una Gal a l’extrem no reductor. Tot i això, l’afinitat de l’enzim és superior per a donadors amb Glc (KM inferiors a les dels donadors amb Gal). D’altra banda, s’ha demostrat que el lípid aniònic DOPG es comporta com a activador de l’activitat enzimática. GT-MG517 posseeix un teòric domini d’unió d’UDP-Glc a l’extrem N-terminal. Aquesta zona presenta similitud de seqüència amb altres glicosiltransferases i permet la classificació de GT-MG517 dins de la família GT-2. En canvi, el seu extrem C-terminal presenta una seqüència particular que no s’alinea amb altres proteïnes. En aquesta tesi es formula la hipòtesi que aquesta zona podria ser d’interacció amb la membrana i, a més, que aquesta interacció podria regular l’activitat enzimàtica. Per això es preparen diverses formes truncades de GT-MG517, en les quals s’eliminen alguns aminoàcids de l’extrem C-terminal, i una forma en la qual només es conserva l’hipotètic domini d’unió d’UDP-Glc. Aquestes noves proteïnes s’expressen, solubilitzen i purifiquen aplicant el protocol establert per a la forma completa. Amb l’anàlisi dels glicolípids sintetitzats s’estableix que els deu últims aminoàcids de GT-MG517 són prescindibles per a la seva activitat, ja que les formes truncades corresponents continuen tenint la capacitat de sintetitzar glicolípids. No obstant, l’eliminació d’un nombre superior de residus, inactiva la proteïna. La purificació de l’hipotètic domini d’unió d’UDP-Glc posa de manifest que forma oligòmers, de la mateixa forma que ho fa la proteïna completa.
Esta tesis se centra en el estudio de las posibles glicosiltransferasas de Mycoplasma genitalium involucradas en la síntesis de glicolípidos. Estas moléculas constituyen parte de la membrana plasmática del miroorganismo, única estructura de protección frente al entorno ya que los micoplasmas carecen de pared celular. La hipótesis sobre la cual se ha desarrollado el trabajo es la posibilidad que los mencionados glicolípidos y las enzimas encargadas de su producción, las glicosiltransferasas, sean esenciales para la viabilidad del micoplasma y, por tanto, su inhibición sea una forma de erradicar las infecciones causadas por el patógeno. De las tres secuencias clasificadas como glicosiltransferasas en el genoma de Mycoplasma genitalium, mg025, mg060 y mg517, se determinó que mg025 es el único de los tres genes que no es esencial para la bacteria, aunque se observó que los tres se expresan tanto en la fase exponencial como en la fase estacionaria de su crecimiento. Se desconoce todavía la función de mg025 y mg060. En cambio, se conoce que mg517 es la glicosiltransferasa responsable de la síntesis de los dos principales glicolípidos del micoplasma, el monoglicosildiacilglicerol (MGlcDG) y el diglicosildiacilglicerol (DGlcDG). En esta tesis se desarrolló un protocolo de expresión para la glicosiltransferasa codificada por mg517, llamada GT-MG517, el cual emplea una coexpresión con chaperonas y solubiliza la proteína con detergentes, glicerol y una fuerza iónica elevada. Dicha metodología fue necesaria ya que GT-MG517 es una proteína asociada a membrana y su expresión recombinante en E.coli presenta dificultades. La proteína se purificó mediante cromatografía de afinidad por Ni pero el grado de pureza obtenido no fue suficiente para intentar su cristalización. Distintas pruebas realizadas usando cromatografía d’exclusión molecular permitieron determinar que GT-MG517 forma oligómeros de alto peso molecular. Con la proteína purificada se realizó un estudio cinético de su doble actividad glicosildiacilglicerolsintasa. De este estudio se extrae que GT-MG517 puede transferir un azúcar, Glc o Gal, a una molécula principalmente hidrofóbica, como es el DOG, y a una molécula mucho más hidrofílica, como el MGlcDG. Pese a su diferencia, los dos compuestos poseen un alcohol primario sobre el que tiene lugar la transferencia creándose el enlace (16). Con cualquiera de los sustratos aceptores probados, la enzima presenta actividades específicas superiores si el sustrato dador es UDP-Gal. El aceptor preferido de GT-MG517 es el lípido DOG, aunque la glicosiltransferasa es capaz de elongar, ya sea con una Glc o con una Gal, glicolípidos como el MGlcDG y el MGDEG, prefiriendo en este caso el compuesto con una Gal en el extremo no reductor. Aún así, la afinidad de la enzima es superior para dadores con Glc (KM inferiores a las de los dadores con Gal). Por otro lado, se demostró que el lípido aniónico DOPG se comporta como activador de la actividad enzimática. GT-MG517 posee un dominio teórico de unión de UDP-Glc en su extremo N-terminal. Esta zona presenta similitud de secuencia con otras glicosiltransferasas y permite la clasificación de GT-MG517 dentro de la familia GT-2. En cambio, su extremo C-terminal presenta una secuencia particular que no se alinea con otras proteínas. En esta tesis se formula la hipótesis que dicha zona podría ser de interacción con la membrana y, además, que dicha interacción podría regular la actividad enzimática. Por eso se prepararon distintas formas trucadas de GT-MG517, en las cuales se eliminaron algunos aminoácidos del extremo C-terminal, y una forma en la cual sólo se conservó el hipotético dominio de unión de UDP-Glc. Las nuevas proteínas se expresaron, solubilizaron y purificaron aplicando el protocolo establecido para la forma completa. Con el análisis de los glicolípidos sintetizados se determinó que los diez últimos aminoácidos de GT-MG517 eran prescindibles para su actividad, ya que las correspondientes formas truncadas conservaban su capacidad de sintetizar glicolípidos. No obstante, la eliminación de un número superior de residuos inactiva la proteína. La purificación del hipotético dominio de unión de UDP puso de manifiesto que forma oligómeros, de la misma forma en que lo hace la proteína completa.
This thesis is focused on the glycolipid producing glycosyltransferases from Mycoplasma genitalium. Glycolipids are part of the microorganism plasma membrane, which is the external covering of mycoplasmas since they lack a cell wall. Our working hypothesis is that glycolipids and the enzymes responsible for their production are essential to mycoplasma. Thus, glycosyltransferase inhibition could be a way to eradicate this pathogen caused infections. There are three genes described as putative glycosyltransferases in Mycoplasma genitalium genome, mg025, mg060 and mg517. We determined that mg025 is the only one essential to the bacteria, although the three of them are expressed both during the exponential and stationary growth phases. The function of mg025 and mg060 still remains unknown, whereas mg517 codifies for the glycosyltransferase responsible for monoglycosyldiacylglycerol (MGlcDG) and diglycosyldiacylglycerol (DGlcDG) synthesis, main mycoplasma glycolipids. In this work an expression protocol for mg517 codified glycosyltransferase was designed. The protocol included chaperone coexpression and protein solubilization with detergents, glycerol and high ionic strength. This methodology was necessary since GT-MG517 is a membrane associated protein and its recombinant expression in E.coli presents some difficulties. GT-MG517 was purified by Ni affinity chromatography. However, a suitable purity degree to attempt protein crystallization was not achieved. Some experiments using size exclusion chromatography revealed that GT-MG517 forms high molecular weight oligomers. A kinetic study of the protein double glycosyldiacylglycerol synthase activity was performed. From this study we learned that GT-MG517 is able to transfer a sugar moiety, Glc or Gal, both to a hydrophobic molecule such as DOG or to a more hydrophilic compound such as MGlcDG. These acceptor substrates share a primary alcohol where the sugar transfer takes place forming a (16) bond. The enzyme presents higher specific activities when UDP-Gal acts as reaction donor, regardless of the acceptor tested. DOG is the preferred acceptor although the enzyme is able to transfer Glc or Gal moieties to glycolipids such as MGlcDG and MGDEG. In this case, the reaction is faster with acceptors with Gal in the non-reducing end. As for donor substrate, enzyme’s affinity is higher for Glc containing molecules, with lower KM values than for Gal donors. In addition, our study proved the anionic lipid DOPG to act as an enzymatic activity enhancer. GT-MG517 has a putative binding domain for UDP-Glc in the N-terminal end. This sequence is similar to other glycosyltransferases and allows its classification in Cazy’s GT-2 family. On the contrary, the C-terminal end has a particular sequence which does not match up with any other protein. Our hypothesis was that this C-terminal end of GT-MG517 could contain a membrane interaction sequence, which could at the same time modulate enzymatic activity. To test this hypothesis some truncated forms of GT-MG517, where C-terminal aminoacids had been removed, were prepared. Moreover, a form where only the putative UDP-Glc binding domain was conserved was also expressed. All these proteins were expressed, solubilized and purified with the same protocol used for the full-length form of GT-MG517. Glycolipids produced by truncated forms were analysed and results implied that the last ten aminoacids were not involved in the enzyme’s activity. Elimination of a higher number of aminoacids caused protein inactivation. When the putative UDP-binding domain was purified, it showed high molecular weight oligomers such as those developed by the complete form of the protein.

En jämförelsestudie mellan svenska och kinesiska mejeriförpackningar som delvis genomfördes i Shanghai, Kina. Omfattar även en färgstudie samt en undersökning om personers uppfattning av färger kontra fetthalt.

Despite emerging water shortages, most water is only used once, and often with low efficiency. However, with appropriate treatment, water can be re–used to reduce the demand on freshwater sources. The Department of Water Affairs, South Africa, promotes industries to reduce discharges into water resources in order to sustain an overall good water quality of all water systems. All of this ultimately leads to industries striving towards zero effluent discharge. Primary Column Bottoms (PCBs) is a wastewater stream derived from the Fischer–Tropsch Gas to Liquid process and consists mainly of organic acids, but no nitrogen or phosphorous, which by implication excludes possible biodegradation. In the operation of cooling towers in industrial processes, cooling water quality has a direct impact on the cooling performance of the system, where nutrient levels may affect fouling, scaling and corrosion observed in the cooling towers. Fouling, scaling and corrosion affect the operating efficiency of cooling water systems and may necessitate the addition of chemical agents to control these phenomena. This has a financial and labour time impact on the operation of these systems. In this study a mini cooling tower test rig was operated with a synthetic PCB effluent as cooling water and various cycles of concentration, pH and linear flow velocities (LFVs). A constant delta temperature of 10 °C was maintained. Cycles of concentration (COC) evaluated included 2, 4 and 6 cycles of concentration and linear flow velocities evaluated was 0.6 m/s, 0.9 m/s and 1.2 m/s. Fouling, scaling and corrosion rates were determined using corrosion coupons and heat exchanger tubes for mild steel and stainless steel. Besides the evaluation of the various operational parameters for fouling, scaling and corrosion, the possibility for chemical oxygen demand (COD) removal by operating the cooling tower as a bioreactor was also evaluated. To this end nutrient correction was applied to the reactor to allow for a CNP ratio of 100:10:1. With regard to fouling, scaling and corrosion, mild steel was more affected by fouling, scaling and corrosion compared to stainless steel where almost no fouling, scaling and corrosion was observed. Overall increased linear flow velocities resulted in higher fouling and scaling rates, whereas lower linear flow velocities resulted in decreased corrosion rates. In terms of cycles of concentration, increased COC resulted in higher fouling, scaling and corrosion rates. Despite the high nutrient removal levels, the accompanying fouling, scaling and corrosion was still below the particular industry’s guidelines. Besides physical–chemical evaluation of the towers under the various operational conditions, culture–dependent and culture–independent methods were also employed. Concerning culture–dependent approaches the study demonstrated that aerobic and anaerobic organisms are present in both the planktonic and sessile phase of the cooling tower reactors. Heterotrophic aerobes were found to be the most abundant under all the operating conditions. Sulphate reducing bacteria were more abundant in the sessile phase of the cooling towers, and the presence of high sulphate levels in the experiments could be indicative of the sulphate reducing bacteria actively participating in the microbial community. Lower than expected corrosion levels, however, suggest that a combination of the organisms in the biofilm rather than sulphate reducing bacteria alone, contributed to the corrosion rates observed. Culture–independent methods, specifically phospholipid fatty acid analysis supported the results from the culture–dependent methods. Furthermore results demonstrated that linear flow velocity had a greater effect on the community structure than cycles of concentration. Finally molecular methods, specifically denaturing gradient gel electrophoresis, found that increasing cycles of concentration resulted in increased microbial community diversity, while increasing linear flow velocity resulted in decreased microbial community diversity. Regarding COD removal, nutrient correction of the synthetic PCB effluent achieved 89.35 % COD removal at 2 COC and 1.2 m/s LFV, while 80.85 % COD removal was achieved at 4 COC at 1.2 m/s LFV. From these results it was recommended that the operation of the cooling tower should be at 4 COC and 1.2 m/s, which despite slightly lower % COD removal, were characterised by fouling, scaling and corrosion rates well within guidelines.
Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2012.

CALLARI. R. Produção de óleo diesel limpo a partir do gás natural: estudo de viabilidade técnico-econômica para a instalação de uma planta gtl (gas-to-liquids) no Brasil. 2007. 84 p. Tese de Mestrado ? Programa Interunidades de Pós-Graduação em Energia. Universidade de São Paulo. A tecnologia de produção de combustíveis sintéticos iniciou seu desenvolvimento a partir de 1919, na Alemanha, tendo o carvão mineral como insumo para a gaseificação. Este processo conhecido como Gas-To-Liquids (GTL) é uma transformação química que gera produtos líquidos e estáveis à temperatura e pressão ambientes. Essa transformação pode ser realizada no próprio local de produção do gás, evitando investimentos e problemas ambientais na construção de gasodutos. No Brasil, o gás natural apresenta crescente incremento da sua produção, e forte aumento das suas reservas, tanto associado quanto não-associado ao petróleo. Dessa forma, como as estruturas de plataformas normalmente se localizam em áreas remotas, torna-se custoso o aproveitamento desse gás que é liberado pela produção do óleo, sendo o mesmo queimado ou ventado. Devido às restrições estabelecidas pela legislação ambiental, a queima do gás natural nas plataformas de produção passa a ser problemática e crítica. Este trabalho visa avaliar a economicidade da implantação de uma planta para a produção de GTL no Brasil, de modo a permitir a manutenção da produção de petróleo dentro das limitações das leis ambientais, e também gerar um melhor aproveitamento do gás natural, produzindo materiais com maior valor agregado. Assim, para desonerar a produção dos líquidos, a instalação de plantas de transformação de gás natural em GTL, centralizada em áreas de grande produção de gás associado, poderia ser a solução para a queima do gás liberado na produção do óleo. Da mesma forma, as plantas de transformação em GTL poderiam permitir a monetização do gás remoto, através da facilidade de transporte do GTL produzido. Palavras-Chave: gás natural, gas-to-liquids, avaliação econômica, diesel limpo, Fischer-Tropsch
CALLARI. R. Production of liquid hydrocarbons employing Natural Gas: a study of the technical and economical feasibility of a GTL plant in Brazil, 2007. 84 f. Work. Program of Post-Graduation in Energy, Universidade de São Paulo, São Paulo, 2007. The development of the technology for the production of synthetic fuels from the gasification of coal started in 1919 in Germany. For a period of time the liquid hydrocarbons production increased and within the years, it was almost discontinued. The technology known as Gas-To-Liquids (GTL) refers to a chemical transformation that generates liquid products that are stable at room temperature and pressure. The transformation can be accomplished close to the natural gas production sites. In Brazil, the production and use natural gas has been growing because of the increase of the reserves of both, associated and non-associated gas. Natural gas is produced from oil explotation. The production of the liquid fractions requires processing steps. Since the offshore installations are located in distant areas, the use of the gas produced is expensive and in many cases, the gas is burned or exhausted. Due to environmental restraints the gas burning turns to be a critical issue. In order to cheapen the production of liquid products, the installation of plants to transform natural gas through the GTL technology, in associated oil and gas production installations could be the solution for the gas burning or exhaustion. The GTL plants could allow the monetization of the remote gas through the transportation of the GTL fuels produced. This work presents an evaluation of the economic costs for the implantation of a GTL plant in Brazil, in a way that allows the oil production to be kept within the environmental requirements and to generate a better use of natural gas.

O objetivo do trabalho é fazer a avaliação global de alguns dos modos energéticos de transporte do gás natural (gasodutos, GNL e GNC), inclusive como energia secundária (eletricidade e GTL). Para a escolha do melhor modo de transporte, além dos custos de cada projeto, serão considerados outros três fatores, que são: impactos ambientais, impactos sociais e riscos políticos. Para isto foi escolhida uma ferramenta de análise conhecida como Avaliação de Custos Completos (ACC), sendo que esta considera os quatro fatores citados anteriormente como de mesma importância na avaliação para um planejamento que vise a sustentabilidade. Para melhor visualização e entendimento do trabalho, foi feito um estudo de caso para o transporte de energia (gás natural e/ou eletricidade) para atender mercados consumidores na região de fronteira entre o Brasil e a Bolívia. Fundamentalmente o estudo do transporte foi feito em solo boliviano, correspondente entre os campos produtores de gás, localizados em Margarita, até a região de fronteira próxima a Corumbá no Mato Grosso do Sul (MS), e também próxima a uma região com grandes jazidas de minério de ferro conhecida como El Mutún. Metodologicamente dentro das quatro dimensões consideradas, foram usados alguns subcritérios mais relevantes para esta análise. Para todos os sub-critérios foram atribuídas notas específicas, de acordo com a região e com o tipo de transporte de energia, e após isto os dados foram passados para um software de tomada de decisão chamado Decision Lens, obtendo assim um rank das melhores opções transporte para a região. Como resultado, o mais coerente para atender a região, são gasodutos de transporte para as demandas elétricas e de gás natural (consumo do MS mais Mutún) e trens carregados com derivados líquidos do gás natural (GTL) para atender a demanda de diesel do MS.
The objective of this work is to make a global evaluation of some energy ways of transport of natural gas (gas-pipelines, LNG and CNG), as well as secondary energy (electricity and GTL). For the selection of a better way of transport, beyond the costs of each project, others three factors were considered: environmental impacts, social impacts and political risks. To perform this, a tool of analysis known as Evaluation of Complete Costs (ACC in portuguese) was chosen. This tool considers the four factors above mentioned as having the same importance in the evaluation process for planning that aims towards sustainability. For better visualization and understanding of the work, a case study for energy transport was made (natural gas and/or electricity) to supply the consumer markets in the region bordering Brazil and Bolivia. Basically the study of the transport was made in Bolivian territory; at the producing gas fields located in Margarita as far as the region bordering Corumbá in the Mato Grosso do Sul area, and also next to a region with great known iron ore deposits known as El Mutún. Methodologically, within the four dimensions above, some more relevant sub-criteria for the analysis were used. For all the sub-criteria considered specific ranks were taken, in accordance with the region and type of transported energy, and after this the data was fed to a software called Decision Lens, thus getting a rank of the best options to carry gas to the region. The results, most coherent way to supply gas to the region, happens to be gas-pipelines of transport for the electric and natural gas demands (consumption in MS plus Mutún) and trains with liquid derivatives of natural gas (GTL) to supply care of the demand of diesel of MS.

Water in South Africa is becoming limiting due to economic growth, social development and the country's water demand that exceed its water availability. Water conservation in the industry can be accomplished by the reuse of process water instead of direct treatment and discharge. By reusing a process effluent as cooling water in cooling towers, the water requirements of an industry, such as Sasol, will be lower and a zero effluent discharge scenario could be achieved. At Sasol, during the gas-to-liquid (GTL) conversion process, natural gas is converted to diesel and other products. During this process an aqueous effluent stream is produced in the Fischer-Tropsch (F-T) reactors known as Primary Column Bottoms. Primary Column Bottoms can be re-used as cooling water within cooling towers. Although this approach is technically feasible, the re-use of process water in cooling systems is characterised by major problems (fouling, scaling and corrosion) due to the complicated chemistry of the process water and the increased nutrient loads within the system. The aim of this study was to evaluate the suitability of Fischer-Tropsch gas-to-liquid Primary Column Bottoms as process cooling water by analysing the microbial community dynamics, fouling, scaling and corrosion. Due to the corrosive nature of this process effluent, stabilisation of the water was essential. To determine whether efficient stabilisation was attained, an accelerated corrosion test was performed. Influence of the external operating parameters within the cooling tower on the rate of fouling, scaling and corrosion were also determined. Structural and functional diversity of planktonic and sessile communities were studied by making use of conventional microbiological techniques (plate counts, MPN technique) and molecular methods (PLFA, DGGE). The accelerated corrosion test of 28 days conducted on mild steel and stainless steel (316L) corrosion coupons accelerated corrosion by immediately establishing the mature natural environment that causes corrosion. The test solution was stabilised as well as non-stabilised synthetic Primary Column Bottoms, in order to compare the effect of stabilisation. Scaling and corrosion indices were also calculated on stabilised and non-stabilised water to determine the scaling and corrosive tendencies of the water and how this correlates with the actual corrosion results obtained. According to the Langelier Saturation Index (LSI), Rymar Stability Index (RSI) and the Puckorius Scaling Index (PSI) the stabilised water was slightly scale forming with little corrosion and the non-stabilised water being more corrosive than scale forming. Average corrosion rate of the stabilised water was 0.032 m d y and 0.049 m d y for non-stabilised water. Average scaling rate was calculated as 7.269 mg/dm2/d for stabilised water and 5.853 mg/dm2/d for non-stabilised water. It can therefore be concluded that effective stabilisation was achieved since stabilised water was less corrosive than non-stabilised water which was also confirmed through experimental data (corrosion rates from accelerated corrosion test) and corresponded with the corrosive tendencies obtained from the scaling and corrosion indices. A lab-scale cooling tower was operated with stabilised synthetic Primary Column Bottoms as cooling water. Five experiments were conducted under varying flow rates and cycles of concentration. Influence of the external operating parameters (linear flow velocity and cycles of concentration) on fouling, scaling and corrosion rates of mild steel and stainless steel (316L) corrosion coupons and heat exchanger tubes were determined through weight loss measurements. Routine physico-chemical analyses, EDS (energy dispersive spectrometry) microanalysis as well as scaling and corrosion indices of each experiment were also compared, in order to evaluate the influence of cycles of concentration and linear flow velocity. Based on the results obtained, it was evident that the variation in cycles of concentration and linear flow velocity had a significant effect (p0.05) on the fouling, scaling and corrosion rates on the mild steel corrosion coupons and heat exchanger tubes. Experimental runs operated at low flow rates of 0.6mIs and 0.9 d s resulted in relative high fouling, scaling and corrosion rates. Operation at 3 and 4 cycles of concentration had the highest scaling and corrosion rates. The COD within the cooling tower was not removed by the microorganisms within the planktonic and sessile communities and resulted in a build-up of COD in the sump. Thus, the cooling tower cannot be used as a bioreactor to biologically degrade volatile organic acids and hydrocarbons. To evaluate the structural and functional diversity of the bacterial and fungal communities. plate counts, most probable number technique, phospholipid fatty acid (PLFA) analysis as well as denaturing gradient gel electrophoresis (DGGE) was used. According to PLFA profiles the community structure within the planktonic and biofilm samples of the experiments operated at low linear flow velocities were similar. The same percentages of Gram-positive, Gram-negative bacteria and fungi occurred, The community structure composition of the planktonic and sessile phases in the experiments operated at higher linear flow velocities was also similar. PLFA analysis concluded that the highest estimated viable biomass was in experiment 1 which had a low linear flow velocity of 0.6 d s . Shannon-Weaver index analysis of DGGE profiles (general structural diversity) indicated that the planktonic bacterial diversity of experiment I and 2 were the highest. Experiment I and 2 were operated at a linear flow velocity of 0.6 and 0.9 m/s respectively. The biofilm samples that had the highest Shannon-Weaver diversity index were experiment 1 and 5. Both experiment 1 and 5 were operated at a linear flow velocity of 0.6 m/s. Morphological changes between planktonic and sessile communities were monitored through scanning electron microscopy (SEM). SEM results illustrated that the planktonic and sessile microbial populations throughout the five experiments were similar, based on morphology. According to the results obtained from the MPN technique, the experiment operated at the lowest linear flow velocity had the highest numbers of sulphate reducing bacteria and also resulted in the highest corrosion rate. Both experiments that were operated at a low linear flow velocity of 0.6 d s had the highest bacterial numbers and also resulted in high fouling rates. However, no relationship exists between the percentage increase in the numbers of aerobic bacteria and the cycles of concentration at which the cooling tower was operated. These observations are supported by results from PLFA profiles that showed that the community structure within the planktonic and sessile samples of the experiments operated at low linear flow velocities were similar. The planktonic and sessile phases of these two experiments had similar levels of Gram-positive-, Gram-negative- bacteria and fungi. The community structure composition of the planktonic and sessile phases in the experiments operated at high linear flow velocities was also similar. PLFA analysis further demonstrated that the highest estimated viable biomass was in the experiment operated at a low linear flow velocity of 0.6 m/s. Shannon- Weaver index analysis of DGGE profiles (general structural diversity) also indicated that the planktonic bacterial diversity during operation at low linear flow velocities were the highest. Although scanning electron microscopy results illustrated that the planktonic and sessile microbial populations throughout the five experiments were generally similar. these results supported the observations of the other techniques. These techniques all supported the notion that corrosion rates may not be directly related to the total microbial biomass or the number of species on mild steel or stainless steel. Corrosion rates seem to be more profoundly affected by biofilm composition within the sessile phase. Based on the results obtained when using Primary Column Bottoms as cooling water, it were evident that variation in cycles of concentration and linear flow velocity had a significant effect (p>0.05) on the fouling, scaling and corrosion rates on mild steel corrosion coupons and heat exchanger tubes. Low linear flow velocities resulted in high fouling rates, increased bacterial numbers as well as high bacterial and fungal diversities. High cycles of concentration resulted in high scaling and corrosion rates and also had the result of similar community structure profiles. This research study could facilitate the selection of optimised operational parameters for the re-use of industrial process water (such as Primary Column Bottoms) as cooling water to minimise fouling, scaling and corrosion.
Thesis (M. Environmental Science (Water Science))--North-West University, Potchefstroom Campus, 2007

Esta pesquisa abordou a questão do desenvolvimento social e econômico do Parque Estadual Turístico do Alto Ribeira (PETAR), localizado no sul do estado de São Paulo, a partir de um estudo geográfico realizado sob a luz da tríade analítica GTP: Geossistema, Território e Paisagem. Partindo dessa análise geográfica, foi possível identificar como as potencialidades e fragilidades do meio físico influenciaram na territorialização da região onde hoje se encontra o parque, e como a paisagem cultural é construída sobre esta realidade. Com isso foi possível contrapor a interpretação dos dados levantados ao Plano de Manejo proposto para o PETAR em 2010, que se encontra, desde aquele ano, sob análise no Conselho Estadual do Meio Ambiente do estado de São Paulo. O documento apresenta contradições internas no que tange à exploração dos recursos minerais. Com a aprovação da Lei Estadual 16.260/2016, que concede 25 unidades de conservação para a exploração da iniciativa privada, é necessário que não restem pontos obscuros no Plano de Manejo, para que fique claro quais são os recursos que poderão ou não serem explorados. Há indícios de que neste processo os interesses econômicos se sobrepuseram tanto ao objetivo de preservação da área como ao do desenvolvimento socioeconômico. Com essa problemática em foco, discutimos como a Geografia e as ciências, de maneira geral, podem ser úteis ao processo civilizatório ao estabelecer critérios éticos de forma objetiva, apontando assim, as causas dos problemas regionais relacionados à territorialização, as contradições políticas deste processo e de que forma seria possível promover o desenvolvimento socioambiental na região. Um dos principais problemas que levantamos foi a questão das restrições às atividades econômicas impostas pela legislação ambiental. Tendo o turismo como única fonte de sustento possível, a região se tornou altamente dependente dos programas de transferência de renda que, nos últimos anos, provaram ser cruciais para a redução da pobreza extrema e evolução dos índices de desenvolvimento humano. Uma vez que uma flexibilização muito grande das restrições ambientais seria desaconselhável e, levando em consideração que a área do parque é ocupada, historicamente, por populações tradicionais, como comunidades quilombolas, concluímos que seria razoável demandar do estado alguma compensação financeira. Esta medida evitaria que recaíssem, exclusivamente sobre a população local, os custos de uma conservação ambiental que é de interesse do conjunto da sociedade.
This research addressed the issue of the social and economic development of the Upper Ribeira State Tourist Park (PETAR), in the state of São Paulo, Brazil, from a geographic study conducted under the light of the analytical triad GTL: Geosystem, Territory and Landscape. Based on this geographical analysis, it was possible to identify how the potentialities and fragilities of the physical environment influenced the territorialization of the region where the park is today, and how the cultural landscape is built on this reality. Thus, it was possible to counter the interpretation of the data collected with the proposed Management Plan for PETAR in 2010, which has been under analysis by the State Environmental Council of the state of São Paulo since that year. The document presents internal contradictions regarding the exploitation of mineral resources. With the approval of State Law 16.260 / 2016, which grants 25 conservation units for the exploitation of the private initiative, it is necessary that there are no obscure points in the Management Plan so it is clear which resources may or may not be exploited. There are indications that, in this process, economic interests overshadowed both the objective of preserving the area and that of socioeconomic development. With this problematic in focus, we discuss how Geography and the sciences, in general, can be useful to the civilizational process by establishing objective ethical criteria, thus pointing to the causes of regional problems related to territorialization, the political contradictions of this process and how it would be possible to promote socio-environmental development in the region. One of the main problems raised is the issue of the restrictions on economic activities imposed by the environmental legislation. With tourism as the only possible source of income, the region has become highly dependent on income transfer programs which, in recent years, have proved to be crucial for the reduction of extreme poverty and the improvement of the human development indexes in the area. Since a significant relaxation of environmental restrictions would be inadvisable, and considering that the area of the park has historically been occupied by traditional populations such as quilombola communities, we have concluded that it would be reasonable to demand financial compensation from the state. This would prevent the local population from paying, alone, for the costs of an environmental conservation, that is in the best interest of society, as a whole.

Within this body of work several series of experiments will investigate the nature of complex combustion in an experimental single-cylinder engine emulating a modern passenger car size compression-ignition (CI) engine. Regimes of single, piloted single and piloted split-main injections will be tested and compared in terms of combustion characteristics, specific emission output and cyclic behaviour to determine how increased injection complexity affects the emissions and output of the modern CI engine. Through these tests, the effect of fuel-line stationary waves will be demonstrated and investigated, showing conclusively that optimised engine calibration is essential to account for injector-generated waves in any multiple injection scenario. This data will then be confirmed with a dedicated analysis using an injector rate measuring tube. The tests will then be expanded to include examination into the behaviour of injector needle-lift standard deviation over its operating cycle, in-cylinder pressure standard deviation behaviour and trends over the combustion cycle as well as IMEP variability. Through these tests a novel method to detect start of combustion will be proposed and compared to conventional methods. Low temperature combustion (LTC) will be tested under incremental injection complexity. Tests will be optimised for combustion phasing and injection pressure, with a view to analysis of emissions, output and cyclic behaviour to establish whether the knowledge gained about conventional combustion holds true under LTC. Optimization of engine parameters will be shown to result in easier to implement LTC regimes with superior emissions characteristics. Finally, LTC tests will be expanded to include 30% and 50% by volume gas-to-liquid fuel (GTL) blends in order to determine whether fuel characteristics further influence emissions, output and cyclic behaviour in LTC through complex injection regimes. How GTL-blend ratio affects trends in emissions and cyclic behaviour will also be examined and compared to conventional diesel fuel.

La réaction catalytique appelée Synthèse de Fischer Tropsch (SFT) permet de transformer du gaz de synthèse, i. E. Mélange de H2 et de CO, en une distribution d’hydrocarbures (CnH2n+2 avec 1 < n < 60-100), plus ou moins saturés et plus ou moins oxygénés. La voie GTL (Gas-To-Liquids) incluant la SFT, est donc une opportunité permettant de transformer les gaz de torchage des puits de pétrole et/ou les stranded gas en produits utilisables dans les moteurs automobiles ou d’avion. Les catalyseurs utilisés jusqu’alors dans les procédés Fischer-Tropsch sont composés de cobalt ou de fer déposés sur alumine ou silice, et, bien que présentant de bonnes performances, ceux-ci sont fortement limités par la forte exothermicité de la réaction, qui induit une élévation importante de la température à la surface du catalyseur et donc une sélectivité vers les produits désirés relativement faible. Dans ce contexte, le carbure de silicium (β-SiC) a été proposé comme support de remplacement aux supports oxydes classiques de manière à mieux évacuer la chaleur dégagée par la réaction et conserver ainsi une meilleure sélectivité de la réaction même à haute conversion. De plus, il a été proposé d’étudier l’impact de la morphologie du support catalytique (extrudés, mousses alvéolaires) sur la réaction de Fisher Tropsh. Il s’est avéré que les propriétés intrinsèques des supports alvéolaires à base de β-SiC (bonne conductivité thermique effective, faible perte de charge, etc…) laissent entrevoir de nouvelles perspectives pour la réaction de Fischer Tropsch en lit fixe. Lors de nos travaux, le carbure de silicium en tant que support a montré de meilleures activités que l’alumine, que ce soit sous forme d’extrudés ou sous forme de mousse. En effet, des emballements thermiques ont été observés sur alumine alors que l’utilisation du β-SiC a permis un meilleur contrôle des gradients de température dans le lit catalytique et ainsi une meilleure sélectivité de la réaction catalytique. Une étude approfondie a permis d’estimer l’influence de la charge en phase active sur les performances catalytiques du catalyseur supportés sur mousses de β-SiC. Un modèle géométrique simple a été développé afin d’estimer la perte de charge induite par les supports de type alvéolaire. Une corrélation avec les packed bed a été développée et s’est montrée capable, grâce à la relation d’Ergun, d’estimer les pertes de charge qu’engendre le passage d’un fluide dans la structure des mousses. Enfin, une étude sur les écoulements biphasique au sein des structure type mousse a permis de mettre en évidence les fortes retentions liquides induites par ce type de support en comparaison avec les lits classiques
The catalytic Fischer Tropsch Synthesis (FTS) enables the transformation of synthetic gas, i. E. Mixture of H2 and CO, into a distribution of hydrocarbons (CnH2n+2 with 1 < n < 60-100), more or less saturated and more or less oxygenated. The Gas to Liquids way, including FTS, is consequently an opportunity allowing the transformation of the flared and/or stranded gas into liquid hydrocarbons for car or plane fuelling. This could first reduce the CO2 release in the atmosphere and secondly increase the oil resources by the transformation of natural gas. The classical catalysts used in Fischer-Tropsch processes are composed of cobalt or iron supported on alumina or silica, and, although they present good performances, they are highly constricted by the high exothermicity of the reaction inducing high temperature on the catalyst surface, leading to low selectivity towards desired products (i. E. Long chained parafins). In this context, silicon carbide (β-SiC) has been proposed as replacement support to alumina and silica in order to better evacuate the heat released by the reaction and thus keeping higher selectivity even at high conversion levels. Moreover, always in order to optimize the process, the impact of the catalytic support morphology (extrudates, cellular foams) on the Fischer-Tropsch reaction has been studied. It appeared that the intrinsic properties of the cellular supports (high effective thermal conductivity, low pressure drops) could let foresee new perspectives in the fixed bed FT reaction. In this work, silicon carbide as catalyst support revealed to be far more attractive than alumina both in the form of extrudates or cellular foams. Indeed, thermal runaway have been observed on alumina whereas the use of β-SiC allowed better control of the temperature and thus better selectivity towards C5+ products. A study on the influence of the active phase charge on the catalytic performances of the catalyst supported on β-SiC foams has been performed. A simple geometric model of the foam as been developed in order to estimate the pressure drop induced by the cellular supports. A correlation with classical packed beds was showed to be able to model the pressure loss induced by a gaseous flow in the cellular material. Finally, a study on the biphasic behaviour of β-SiC foams has evidenced higher liquid hold-ups compared to classical packed beds. The influence of this property on the FT reaction has here not been made and will be the subject of a next study

Dans le procédé GTL, la SFT est l’étape qui permet de transformer le syngas en hydrocarbures liquides. L’intérêt d’utiliser le Co/SiC a été démontré. Notre travail consiste à étudier l’influence des paramètres réactionnels : Tréduction, promoteurs ou nature du support sur l’activité. La taille de cobalt, sa réductibilité ainsi que sa cristallinité sont suivies par diverses techniques de caractérisation: DRX, TPR et MEB. Le dopage du Co/SiC avec des traces de Ru a permis d’améliorer sensiblement la dispersion des particules métalliques. Une étude comparative sur des supports (β−SiC) : mousse, extrudés et grains a été réalisée. Afin de mettre en évidence l’inertie chimique et la conductivité thermique du SiC, nous l’avons comparé avec des mousses d’alumine et alumine/SiC. En termes de respect de l’environnement, l’idée directrice de notre travail était de régénérer et recycler le catalyseur. Ceci représente un avantage non négligeable du β−SiC par rapport aux supports conventionnels
In the GTL process, the FTS is the step which transforms the syngas into liquid HC. In catalysis, the interest of using Co/SiC was demonstrated. This work consists in studying the influence of parameters: Treduction, promoters or the nature of the support on the activity. Modifications of the active phase particles size, its reducibility as well as its crystallinity are followed by diverse characterization techniques: XRD, TPR and SEM. The Ru effect on the Co/SiC system enhanced the Co dispersion and consequently the activity. In order to illustrate the best macroscopic shape of β−SiC (foam, pellets and powder), a comparative study on supports was also realized. A second study deals with the chemical nature of supports eg. SiC, Al2O3/SiC and Al2O3. In term of environmental protection, the base idea of this work was to enhance the catalyst life time by its regeneration and its recycling

La régulation de l’Internet constitue depuis toujours un défi pour le droit :le « réseau des réseaux » a été conçu dans un esprit de connectivité universelle, avec la volonté que chaque utilisateur intéressé puisse y relier son ordinateur et accéder aux informations disponibles en ligne, sans que celles-ci soient altérées en fonction du lieu de connexion et donc sans tenir compte d’éventuelles règles nationales, régionales ou internationales. S’il s’inscrit ainsi en porte-à-faux avec les principes fondamentaux du droit national et international, fondés sur la souveraineté des États et sur des frontières géographiques bien établies, l’Internet n’est pas pour autant un espace anarchique. Il constitue plutôt un terrain propice à l’émergence de nouveaux régulateurs et à l’expérimentation de nouvelles formes de normativité. L’espace virtuel global repose en effet sur une architecture physique et informatique qui peut être modelée et sollicitée à des fins de régulation des flux d’informations en ligne. Dans cette optique, notre thèse se penche sur le Domain Name System (DNS), le système de nommage et d’adressage de l’Internet qui assure les correspondances entre les noms de domaine intelligibles pour les humains et les adresses IP numériques utilisées par les ordinateurs pour communiquer entre eux. La structure hiérarchique de cet annuaire global en fait une cible de choix pour ceux qui aspirent à un contrôle centralisé du réseau et des informations qu’il véhicule. Le DNS est administré depuis 1998 par une organisation globale atypique, l’Internet Corporation for Assigned Names and Numbers (ICANN), constituée sous la forme d’une société privée de droit californien, investie de ses compétences en vertu de contrats avec le gouvernement des États-Unis et caractérisée par un modèle de gouvernance multipartite mobilisant des représentants du secteur privé, de la société civile et des gouvernements. Par une étude pragmatique des actes juridiques produits par l’ICANN en vue d’attribuer de nouvelles extensions de noms de domaine génériques – à côté du fameux .com et en parallèle des extensions nationales telles le .be – nous démontrons que l’organisation ne se cantonne pas à une mission essentiellement technique mais se profile, à son corps défendant, comme un régulateur global des contenus en ligne. Nous mettons en évidence, d’une part, que les normes globales édictées par l’ICANN pour justifier le rejet des candidatures indésirables ne visaient pas seulement les termes proposés comme nouvelles extensions mais aussi les conditions d’exploitation envisagées par les candidats, afin d’assurer ex ante la licéité et la qualité des informations présentées dans les futurs domaines. Nous montrons, d’autre part, que l’ICANN a été amenée, sous la pression des gouvernements, à investir ses sous-contractants, les registres et registraires de noms de domaine, d’obligations d’intérêt public relatives au contenu des sites web auxquels leurs noms de domaine donnent accès, en vue de lutter contre les activités abusives et de protéger les consommateurs. Nous démontrons que l’ICANN a ainsi renforcé, sous sa supervision, le rôle des intermédiaires du DNS en tant que points de contrôle du contenu posté en ligne et pointons les dérives potentielles de cette évolution, qui n’est accompagnée d’aucun garde-fou pour préserver la liberté d’expression en ligne.
Doctorat en Sciences juridiques
info:eu-repo/semantics/nonPublished

The MEF2 transcription factor is a central regulator of skeletal and cardiac muscle development. Recently, we showed that MEF2A regulates skeletal muscle regeneration through direct regulation of the Gtl2-Dio3 microRNA mega-cluster. In addition to their expression in skeletal muscle, temporal expression analysis of selected Gtl2-Dio3 microRNAs revealed high enrichment in cardiac muscle. Therefore, I investigated the role of selected microRNAs from the Gtl2-Dio3 noncoding RNA locus in the heart. First, I found that Gtl2-Dio3 microRNAs are expressed at higher levels in perinatal hearts compared to adult, suggesting they function in cardiac maturation shortly after birth. I also demonstrated that these microRNAs are dependent on MEF2A in the perinatal heart and in neonatal cardiomyocytes. To determine the specific role in cardiac muscle, I overexpressed selected microRNA mimics in neonatal rat ventricular myocytes (NRVMs). My results showed that miR-410 and miR-495 stimulate cell cycle re-entry and proliferation of terminally differentiated NRVMs. Subsequent target prediction analyses revealed a number of candidate target genes known to function in the cell cycle and/or in cardiac muscle. One of these was Cited2, a cofactor required for proper cardiac development. Subsequently, I showed that Cited2 is a direct target of these miRNAs and that siRNA knockdown of Cited2 in NRVMs resulted in robust cardiomyocyte proliferation. This phenotype was associated with reduced expression of Cdkn1c/p57/Kip2, a cell cycle inhibitor, and increased expression of Vegfa, a growth factor with proliferation-promoting effects. Given the exciting possibility of manipulating the expression of these microRNAs to repair the damaged heart by stimulating cardiomyocyte proliferation, I then investigated whether they were regulated in cardiac disease and function in pathological signaling. Toward this end, I examined expression of miR-410, miR-495, miR-433, as well as the Gtl2 lncRNA in various cardiomyopathies. Interestingly, the microRNAs and lncRNA were dynamically regulated in mouse models of cardiac disease including myocardial infarction and chronic angiotensin II stimulation. Furthermore, I showed for the first time that the Gtl2 lncRNA and miRNAs are differentially regulated in myocardial infarction, indicating that the complex regulation of the Gtl2-Dio3 noncoding RNA locus may be important for response to cardiac injury. Lastly, I showed that inhibiting select Gtl2-Dio3 microRNAs in pathological signaling attenuated cardiomyocyte hypertrophy in vitro. Therefore, differential targeting of the Gtl2-Dio3 noncoding RNAs could provide new therapeutic strategies to control the response of the heart to cardiac diseases with diverse etiologies.

Recently, the discovery of noncoding RNAs (ncRNAs), such as long noncoding RNAs (lncRNAs) has altered the traditional view of gene regulation. Sequencing of genomes has brought to light the vast stretches of non-protein coding DNA regions that transcribe non-protein coding RNA. LncRNAs are multifunctional and extremely diverse. They can act as signals, decoys, scaffolds, guides, or enhancers. Several lncRNAs, such as Fendrr and Bvht, have been found to have important regulatory functions in cardiac disease and development. The Glt2-Dio3 locus, which is enriched in cardiac muscle, harbors two long intragenic RNAs, MEG3 and MEG8, and harbors one of the largest mammalian miRNA clusters. MEG3, which is termed Gtl2 in rat and mouse, contain 10 exons that are alternatively spliced and give rise to several variants. Gtl2 is conserved across human, rat, and mouse, which makes it an ideal candidate for research and a possible target for therapies. Based on the growing evidence for lncRNAs playing a role in cardiac muscle and our research on the Gtl2-Dio3 microRNAs (miRNAs), I focused on investigating the Gtl2 lncRNA in the heart. Antisense oligonucleotides (GapmeRs) were used to knockdown Gtl2 lncRNA expression levels in cultured, primary neonatal cardiomyocytes in basal and hypertrophic conditions. Although Gtl2 was effectively knocked down in basal conditions I was unable to achieve efficient knockdown in hypertrophic cardiomyocytes induced by phenylephrine treatment. Consequently, I did not observe any modulation of hypertrophy as determined by changes in the expression of Nppa and Nppb, established markers of cardiomyocyte hypertrophy.. Next, I utilized short hairpin RNA (shRNA) to knockdown Gtl2 lncRNA expression levels and obtained robust knockdown. Lastly, I designed a cardiac tropic adeno-associated virus 9 (AAV9) encoding MEG3 DNA for in vivo overexpression experiments as well as an adenovirus encoding MEG3 for in vitro overexpression experiments. These reagents will provide valuable resources for dissecting the functions of the Gtl2 lncRNA. Studies investigating the roles of Gtl2 in the diseased heart my lead to the development of other potential therapies to treat cardiac disease.

碩士
國立成功大學
熱帶植物科學研究所
106
Microorganisms, including fungi and bacteria, effect plant health and play important roles in crop production. In ecosystems, Volatiles emissions by microorganisms have been found to influence plant growth. Volatiles produced by plant growth-promoting microorganisms have a positive impact on plant growth through direct stimulation or increase plant stress resistance. This study isolated the fungi, Tolypocladium sp. GT22, with the ability to improve plant growth. According to the results, GT22 nearly doubles the fresh weight of Nicotiana benthamiana increases and the fresh weight of Arabidopsis thaliana by 70%. Furthermore, the interaction between GT22 and Brassica rapa chinensis was investigated to determine whether GT22 can be used for agricultural purposes. The data indicates that it can significantly increase the fresh weight, chlorophyll, and carotenoids of Brassica rapa chinensis. Gas chromatography-mass spectrometry (GC-MS) was used to separate and identify 40 kinds of Volatiles produced by GT22. Through investigation, it was found that GTC is the critical compound which could improve plant growth. Additionally, Arabidopsis thaliana co-culture with GT22 conferred tolerance to arsenic stress and salt stress. This research indicates that Volatiles of GT22 can promote plant growth and enhance plant abiotic stress tolerance.

Fisher-Tropsch Synthesis is a primary pathway for gas-to-liquid technology. In order to overcome commercial problems associated with reaction and transport phenomena, the use of supercritical solvents has been proposed to increase chemical conversion and improve temperature control. One of the major challenges in designing the supercritical FTS systems is the solvent selection. Numerous alternatives exist and should be screened based on relevant criteria. The main aim of the thesis was to develop a safety metric that can be incorporated in the selection of an optimal supercritical solvent or a mixture of solvents. The objective was to minimize the cost while satisfying safety constraints or to establish tradeoffs between cost and safety. Hydrocarbons from C3 to C9 were identified as feasible solvents for FTS purposes. The choice of these solvents is dependent on their mixture critical temperature and pressure requirements that need to be satisfied upon entry into the FTS reactor. A safety metric system was developed in order to compare the risk issues associated with using the aforementioned solvents. In addition, an economic analysis of using the different solvents was performed. Finally, a case study was solved to illustrate the use of the proposed metrics and the selection of solvents based on safety and techno-economic criteria.

Globally, there are significant quantities of natural gas reserves that lie economically or physically stranded from markets. Options to monetize such reserves include Gas to Liquids (GTL) and Liquefied Natural Gas (LNG) technologies. GTL is a unique monetization option that brings natural gas products to crude oil markets. This technology is commercially immature, appears to have attractive market potential, requires substantial capital investments, and has uncertain operating costs and revenue generation. LNG is a more established monetization option. Project economics for the two technologies are reviewed, as well as literature evaluating such for either or both. Discounted cash flow models are studied for two project scenarios, and results are discussed and compared. The modeling effort seeks to inform the decision to invest in GTL or LNG for the monetization of a stranded gas reserve.
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碩士
國立臺灣大學
植物科學研究所
106
Nitrogen is an essential element of living organisms. Most of the land plants use nitrate (NO3-) as the major nitrogen source. Nitrate transporter 1/peptide transporter family (NPF) is one of the transporter families, which is able to transport nitrate in plants. We analyzed the online public micro-array database of the 53 members of NPF and found out the candidate members that may participate in the responses upon abiotic stresses. The real-time quantitative RT-PCR results showed that NPF2.11/GTR2 is upregulated by salt stress within 12 hours, and showed a less sensitivity of salt-induced inhibition on primary root growth in the gtr2-1 mutant. In addition, gtr2 mutants had lower water loss rate of leaves and lower stomatal conductance than Col-0. The stomatal aperture results showed that gtr2 mutants had functional deficient in stomata under KCl treatment, and this functional deficient can be recovered by supplement nitrate. However, there was more nitrate allocated to shoot in gtr2-1 mutant under normal condition and higher shoot-to-root nitrate content ratio in gtr2 mutants under salt stress. Furthermore, the expression level of NPF7.3/NRT1.5 and NPF7.2/NRT1.8 had similar salt-induced pattern between gtr2 mutants and Col-0. Taken together, this study suggests that GTR2 involved in salt and drought stresses and might not correlate to stress-initiated nitrate allocation to roots (SINAR) in Arabidopsis.

碩士
國立交通大學
科技法律研究所
105
The New gTLD Program initiated by The Internet Corporation for Assigned Names and Numbers (ICANN) allows applicants to become the Registry Operator of a certain Top-Level Domain Name of the applied string.The number of applications reached 1930 during the first round of this program and expected to cause severe impact on the domain name industry which once only existed 22 gTLDs and over 300 ccTLDs. On the premise of domain names, no matter Top Level or Second Level, are valuable resources and should be distributed efficiently to reach efficiency of economics, this article wish to address the issue of whether the distribution mechanisms of Top Level and Second Level domain names have reached “allocative efficiency”, or have reached it indirectly by minimized the” transaction cost” after the New gTLD Program launched in 2011.Based on the aforementioned analysis, this thesis will provide recommendations on related domain names policies to ICANN and the government. This thesis concludes that though there is no classic monopoly effect of under-producing, whether the high application fee is reasonable or falls into a monopoly price still needs further analysis.Moreover, the rights protection mechanisms such as TMCH under this program had effectively eliminated the negative externalities arisen from the floods of cybersquatting as expected and made the distribution of Top Level and Second Level domain names close to allocative efficiency.Nevertheless, this article recommends applicants of generic strings in Top Level should make registration available to the public, and auction generic names in Second Level. ICANN should research on methods to reduce the operation cost of rights protection mechanisms in order to reduce transaction cost of this market, and exclude the market failure factors to promote allocative efficiency.

Please read the abstract (Synopsis) in the section 00front of this document
Dissertation (M Eng (Chemical Engineering))--University of Pretoria, 2007.
Chemical Engineering
MEng
unrestricted

The aim of this research study was to identify and highlight the challenges experienced during the different phases of the shutdown or turnaround management processes in the petrochemical refineries. The data for the research, mainly through qualitative interview sessions and some quantitative comparison data, was obtained from PetroSA GTL Refinery as a case study. The research was subdivided into three areas: the planning, budgeting and shut execution processes. The qualitative interview sessions were conducted with managers and engineers who are directly involved with the shutdown management processes at PetroSA. The research identified the critical departments involved in the process, i.e. the shutdown team, operations, mechanical maintenance, inspection, projects, services etc., and selected respondents from these departments. Two senior managers from one of the large shutdown and turnaround contractors in South Africa were also included in the sample. The findings from the research highlighted interesting responses from the interview respondents. The challenges experienced in the various phases were discussed, with emphasis being placed on the planning, budgeting and shut execution phases of the process. The findings indicated that in order to be competitive in the petrochemical industry, a refinery must strive to achieve higher productivity from the field execution teams, as well as to incorporate proper cost control structures in the process. The research findings and recommendations are shown in chapters 4 and 5 of this report.
Thesis (MBA)-University of KwaZulu-Natal, Westville, 2007.

The purpose of this study was to investigate the impact of the maintenance management system (MMS) on production output and profitability (PO&P) at the Petroleum Oil and Gas Corporation of South Africa (PetroSA) GTL Refinery as a source of competitive advantage. State-Owned Companies and, or more specifically the PetroSA GTL Refinery must maintain its strategic importance for government fuel security but, at the same time, it must compete against private refineries in terms of achieving high production volumes, maximising profitability and to maintain its stake of 6.5% of the available production capacity. The literature review for this study suggested that the maintenance management system (MMS) impacts positively on production output and profitability (PO&P). The MMS has a tremendous influence on PO&P at the PetroSA GTL Refinery. Using a quantitative research design, cross-sectional research survey and the Maintenance Scorecards (MS) assessment tool, this study was conducted on six areas of the PetroSA GTL Refinery. Two population groups, namely production and maintenance groups participated in the survey. Fifty-six respondents belonged to the maintenance group and thirty-eight respondents belonged to the Production Group. All the Maintenance and Production Group respondents completed the MS questions designed to fit the characteristics of these population groups. Correlation analysis in terms of the means, standard deviations, gap analysis, Pearson product moment correlation coefficient (r) as well as the coefficient of determination (R²) was used to analyse the data. The findings of the study indicated a moderate positive linear correlation between the MMS and PO&P. Recommendations based on the findings were tabled in chapter 7 to improve and enhance production perspective (asset health gap), safety perspective (asset prioritisation gap) and the learning and growth perspective (skills and working condition gap).
Business Management
M. Com. ((Business Management)

Guimarães, classificada pela UNESCO em 2011 cidade do Património Cultural da Humanidade, é o berço da nação portuguesa. A presente dissertação consiste num processo de investigação e estudo sobre a identidade cultural do centro histórico de Guimarães e os seus planos de reabilitação e conservação, especialmente no contexto habitacional. Sendo uma cidade com grande valor histórico, começou por se desenvolver dentro das muralhas que também se foram alongando por questões essencialmente defensivas. Esta zona intramuralhas é considerada o centro histórico, zona de especial proteção, e é também o enfoque desta dissertação. Na década de 80 a Câmara de Guimarães fundou o Gabinete Técnico Local, liderado pela Arquiteta Alexandra Gestas, responsável pela restruturação e reabilitação da cidade. Seguindo assim novas políticas urbanas, que já se espalhavam pela Europa, inicia-se uma fase de reabilitação urbanística e arquitetónica da cidade com a premissa de manter o valor patrimonial e identitário, respondendo às novas exigências sociais. Por último apresenta um estudo das habitações caraterísticas do centro histórico dado que nas suas intervenções sempre foi fomentado o uso de técnicas e materiais tradicionais. Este estudo será a base de um trabalho prático com duas propostas de reabilitação para duas casas do centro histórico de Guimarães - uma casa comum e um palacete burguês.
Guimarães, a city classified by UNESCO as World Heritage in 2011, is the cradle/ crib of the Portuguese nation. The present dissertation consists in a process of investigation and study on the cultural identity of Guimarães’ historical centre and its plans of rehabilitation and conservation, especially in the housing context. Being a city with great historical value, Guimarães had its initial development inside the walls that stretched along with time essentially because of defensive matters. The area inside the walls, as knowns as historical centre, has special protection and it is the principal subject in this dissertation. In the 80’s Guimarães’ city hall founded the Local Technical Office (GTL) whose leadership belonged to the Architect Alexandra Gestas. She was responsible for the restructuring and rehabilitation of the city. New urban politics, spread all over Europe, were used to initiate a phase of urbanistic and architectonic rehabilitation in town with the goal of keeping patrimonial and identity value but still answering to the new society needs. At last, this work presents the study of usual historical centre houses’ technical features given that in them were used the most traditional materials and technics. This study is the root for a practical work with two proposals for the rehabilitation of two houses in the historical centre – a common one and a bourgeois mansion.

An experimental study was performed to study soot formation and evolution in atmospheric, laminar, coflow, diffusion flames of Jet-A1, Synthetic Paraffinic Kerosene and their surrogates. Light extinction, rapid thermocouple insertion and thermophoretic sampling followed by transmission electron microscopy and atomic forced microscopy were used to obtain soot volume fraction profiles, temperature profiles and soot morphologies, respectively. Different soot evolution processes were observed on the flame centerline and on a streamline with a significantly different temperature history. Formation and agglomeration of the first soot particles are different on the two streamlines. Transparent liquid-like particles are produced in large volumes in the early regions of the flame centerline where T < 1500 K; these particles are undetectable by the extinction method with the wavelength of 632.8 nm. Most of the currently used computational soot models do not predict the liquid-like nature of nascent soot particles which has major effects on the modeling.