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<p>A supply shortage of solar-grade silicon in recent years resulted from a rapid expansion of the solar cell industry. Therefore, many efforts have been done to obtain reliable metallurgical methods for production of SoG silicon from metallurgical grade silicon.</p> <p>In this research, refining of metallurgical grade silicon by chlorination treatment with the emphasis on Al removal was investigated. Thermodynamic calculations through Factsage confirmed the feasibility of Al removal in repeated steps of chlorination. Therefore, an Ar+SiCl₄ gas mixture with different flow rates was applied to the silicon melt by blowing and injection methods at different temperatures and the ICP-OES was used for analysis of the impurities in silicon.</p> <p>Results revealed that Al removal from silicon by chlorination treatment under the conditions employed in this study is first order reaction with respect to Al. By increasing the temperature in the chlorination process, the rate constant increases which is related to an increase in the liquid mass transfer rate. Also the observed higher rates of Al removal under injection conditions appear to be the result of improved stirring in the melt rather than an increase in the interfacial area.</p> / Master of Applied Science (MASc)

Management of the air quality surrounding Petroleum Refineries deserves attention because the industry contributes almost five percent of the total emissions from all anthropogenic sources. A document containing a complete set of guidelines for use in the refining industry which satisfies the current and anticipated air quality legislations and regulations in the U.S. is necessary. In the past, several documents have been prepared, but have not included a complete coverage of the air quality management as currently needed. Furthermore, due to the continuing revisions of the Clean Air Act, a document with current, updated regulations and air quality management principles is necessary. This study dealt with a broad range of topics including characteristics of emissions, control technology applied, regulations and legislative issues, monitoring and modeling practices, and issues of the 1980s together with future projections and implications. Air quality regulations and standards are periodically revised and are becoming more stringent with time. Issues like acid rain may lead to even more stringent emission standards if investigations carried out currently reveal that the refineries are significant contributors. Great measures are taken to control emissions from the refineries either by using good control equipment or using other alternative control strategies. Small operating refineries are closing down due to changing conditions. An agglomeration and or expansion of the existing refining capacity is occuring. The air quality trends associated with this transition in the industry are discussed. / Master of Science

L'objectif de ce travail de thèse était la caractérisation puis l'étude des applications potentielles dans le domaine des extraits naturels végétaux ou d'origine fermentaire d'un nouvel Extracteur de Partage Centrifuge (EPC) prototype. Ce but originel a été sensiblement infléchit et a conduit, au fil de l'avancement des études menées, à des développements différents et/ou complémentaires à ceux initialement imaginés. ce travail portait au départ sur l'extraction et la purification des métabolites issus principalement des biotechnologies blanches (acides succinique, itaconique,…), mais très rapidement, nous avons été amené à recentrer nos recherches sur d'autres métabolites naturels issus d'extraits de plantes (Glycyrrhiza glabra, Sinapis alba, et Anogeissus leiocarpus) et une seule cible fermentaire (l'acide itaconique). / The aim of this thesis was the characterization and study of potential applications of a new Centrifugal Partition Extractor (CPE) prototype, in the field of natural plant extracts and withe biotechnology. This work initially focused on the extraction and purification of metabolites mainly from white biotechnology (succinic acid, itaconic acid, ...), but very quickly, we have been led to focus our research on other metabolites from natural extracts plant (Glycyrrhiza glabra, Sinapis alba, and Anogeissus leiocarpus) and one target fermentation (itaconic acid).

Master of Science / Department of Mechanical and Nuclear Engineering / Douglas S. McGregor / Purification of cadmium, zinc and tellurium was attempted to improve the quality of cadmium-zinc-telluride (CdZnTe) crystal growth. Specifically, vacuum distillation, zone refining and H[subscript]2 gas flow assisted zone refining were all investigated as methods to purify the constituent elements of CdZnTe. A unique multi-chamber ampoule was used to enable a purification sequence starting with double vacuum distillation followed by zone refining all without sample handling after the initial step. Modifications due to unique material properties of Cd and Zn were developed. Glow discharge mass spectroscopy (GDMS) analysis was used to measure impurity concentrations of 74 elements. Cd purification using vacuum distillation proved to be an effective method to reduce the impurity level of 5N starting material to a purity between the range of 6N5 and 7N5, as measured using GDMS and laser ablation mass spectroscopy. Combined Zn double vacuum distillation and zone refining in an enclosed Ar atmosphere using 5N starting material yielded material with a purity between the range of 5N8 to 6N8. Tellurium purification using combined double vacuum distillation followed by zone refining under continuous H[subscript]2 flow of 4N specified raw material resulted in high purity tellurium between the range of 6N3 and 7N4.

Les diodes électroluminescentes organiques (OLED) ont une durée de vie limitée. Cette limitation est notamment due à la présence d'impuretés dans le matériau électroluminescent. Ces impuretés proviennent principalement des électrodes. Nous pensons que l'ajout de couches de matériaux entre les électrodes et le matériau électroluminescent peut retarder l'arrivée des impuretés. Cette couche ajoutée doit avoir plusieurs caractéristiques dont principalement : être conductrice, ne pas absorber la lumière, être facilement mise en oeuvre et être d'une grande pureté. Nous pensons que des matériaux de type discotique possédant une mésophase aux températures d'utilisation de la OLED peuvent remplir ce cahier des charges. Nous avons choisi d'étudier les composés discotiques à base de triphénylène, car celui-ci n'absorbe pas dans le visible. Nous avons tout d'abord étudié les 2,3,6,7,10,11-Hexa-(alkylthio)triphénylènes (HATT). Les HATT possèdent déjà les propriétés physiques que nous recherchons à l'exception des propriétés thermotropes. Nous avons donc étudié la possibilité de modifier celles-ci. La synthèse de plusieurs HATT possédant six chaînes alkylsulfanyles identiques n'a pas donné les résultats attendus du point de vue des propriétés thermotropes. Nous avons alors synthétisé des molécules possédant plusieurs chaînes alkylsulfanyles différentes. Après différents essais, nous avons trouvé un mélange de molécules possédant plusieurs chaînes latérales différentes ayant les propriétés physiques recherchées. Mais ce matériau est composé d'un grand nombre de molécules et sa purification est difficile. Les techniques classiques de purification des composés organiques ne donnant pas une pureté suffisante, ou étant inapplicables sur une mésophase cristal liquide à température ambiante, nous avons donc recherché d'autres techniques de purification ou d'obtention des propriétés thermotropes désirées. Nous avons étudié la purification par raffinage de zone des matériaux à l'aide d'une impureté que nous avons ajoutée et suivie au cours des manipulations. Le raffinage de zone montre une bonne purification lors de l'utilisation d'une transition de phase entre une phase cristalline et une phase liquide. Par contre, lors de l'utilisation d'une transition impliquant une mésophase (cristal liquide ou cristal plastique), une faible (ou une absence de) purification est observée. Ces deux dernières études ont été faites sur des 2,3,6,7,10,11-Hexa(alkyloxy)triphénylènes (HAOT) que nous avons synthétisés et purifiés au préalable. Les gels de silice fonctionnalisés que nous avons utilisés montrent une purification des cations métalliques durs et, dans une moindre mesure, des cations métalliques intermédiaires dans le concept dur-mou. Le phosphore, seul élément non-métallique que nous ayons étudié, est l'élément dont la baisse de concentration est la moins efficace. La seconde approche pour obtenir des mélanges possédant une mésophase cristal liquide à température ambiante est la formation de mélanges de molécules synthétisées et purifiées isolément. Parmi les mélanges de molécules que nous avons effectués, nous avons pu observer une plage de concentration de mélanges ternaires qui possède les propriétés thermotropes recherchées. Nous avons donc obtenu un matériau cristal liquide à température ambiante grâce à un mélange de molécules. Le matériau ainsi formé absorbe peu dans le visible, possède potentiellement une bonne mobilité des porteurs de charges électriques, est facilement obtenu à une pureté suffisante. Ce mélange de molécules possède donc les propriétés que nous recherchons pour être utilisé comme couche de matériau ajoutée aux OLED.

[pt] Diferentes métodos espectrométricos de análise, incluindo ICP OES, ICP-DRCMS e Q-ICPMS com técnicas hifenadas (geração de hidreto, vaporização eletrotérmica ou cromatografia de íons), foram aplicados na caracterização química de 16 óleos e 41 amostras de efluentes aquosos de uma refinaria de petróleo. O objetivo específico deste estudo foi o de entender o comportamento do selênio (Se) e de suas espécies químicas ao longo do processo de geração e tratamento dos efluentes desta unidade industrial. A caracterização química multielementar das amostras por ICP-MS revelou uma composição muito complexa da maioria deles, com altas salinidades e potenciais interferentes espectrais e não espectrais presentes. Por isso, foi necessária uma reavaliação crítica das técnicas analíticas para a determinação de Se e de suas espécies. As técnicas de ICP-DRC-MS, utilizando CH4 como gás de reação, e de ETVICPMS mostraram o seus potencial para a determinação de Se com melhores limites de detecção (cerca de 0,05 ug L-1 para ambas), mas também as suas limitações na análise de efluentes com altas salinidades. Nas 16 amostras de petróleo analisadas, verificou-se uma grande variabilidade nas concentrações de Se total, cobrindo uma faixa de < 10 ug kg-1 até 960 ug kg- 1, a qual poderia explicar também a carga muito variável deste elemento nos efluentes das diferentes unidades de tratamento. As maiores concentrações de Se total foram encontradas nas águas ácidas, com concentrações de até 1714 ug L-1. Confirmou-se a predominância de SeCN - na maioria das amostras analisadas, mas observaram-se também outras espécies com tempos de retenção diferentes das espécies Se(IV), Se(VI) e SeCN-, especialmente nos efluentes da estação de tratamento de despejos industrais (E.T.D.I.). Em amostras ácidas, identificou-se Se coloidal (Seº) formado pela decomposição de SeCN-, ou de outras espécies pouco estáveis nestas condições. Experiências de bancada com soluções de SeCN- apoiaram esta hipótese. Foi constatada, que o perfil de especiação de amostras coletadas num mesmo local de processamento, mas em épocas diferentes, pode variar significativamente, o que torna difícil a comparação de dados obtidos neste trabalho com os de outros autores. / [en] Different spectrometric methods of analysis, including ICP OES, ICP-DRC-MS and Q-ICP-MS, the latter hyphenated to hydride generation, eletrothermal vaporization or ion chromatography have been appliesd to the chemical characterization of 16 crude oils and 41 effluents samples from a petroleum refinery. The specific objective of this study was to get information on the behavior of selenium (Se) and its species along the different processes of generation and treatment of the effluents.Multielemental characterization of effluents by ICP-MS revealed a complex composition of most of them, with high salinity and potential spectral and non spectral interferents present. For this reason, a critical reassessment of the analytical techniques for the determination of total Se and its species was necessary. DRC-ICP-MS and ETV-ICPMS, using CH4 as cell reaction gas, showed their potential for the determination of Se with better detection limits (about 0,05 ug L-1), but also their limitations for the analysis of effluents with high salinity. A large variability in the concentration of Se was observed in the 16 analysed crude oil samples (< 10 ug kg-1 Se until up to 960 ug kg-1), which may explain also the varying concentrations measured in the effluents. Highest concentrations of selenium were measured in samples from the treatment unit for acid waters (up to 1.714 ug L-1). The predominance of selenocyanate (SeCN-1) was confirmed in most of the effluent samples analysed, but also several other species with retention times different from Se(IV), Se(VI) e SeCN - were observed, especially in samples from the treatment plant. Colloidal Se (Seº) was identified in acid waters, probable formed by decomposition of SeCN - or other unstable species under these conditions. Laboratory experiments with selenocyanate solutions confirmed this hypothesis. The speciation profile of samples collected at the same point, but at different time intervals, showed significant variations, not allowing easy comparison of the results obtained in this work with those of other authors.

Foram tomadas amostras de aço líquido referentes a três grupos de aço, a saber: (I) aços baixo-carbono (0,02 %C 0,08), acalmados ao alumínio; (II) aços peritéticos (0,09 %C 0,15), acalmados ao alumínio e silício; (III) aços ultrabaixo carbono ( C<35 ppm), acalmados ao alumínio.Os aços foram produzidos em aciaria do tipo LD e foram, a seguir, tratados em equipamentos de refino secundário, adequados a cada um dos casos.As amostras forma colhidas no distribuidor de uma máquina de lingotamento contínuo de placas, segundo critério que minimiza a possibilidade da ocorrência de interferências que pudessem mascarar o resultado do tratamento de refino secundário tais como re-oxidação do aço e coleta simultânea de escória. As amostras foram submetidas à análise de inclusões utilizando-se técnicas de microscopia óptica, microscopia eletrônica e micro-análise. Foi possível caracterizar as inclusões presentes em cada tipo de aço segundo a morfologia, o tamanho, a quantidade e a composição química. / Non-metallic inclusions in liquid samples of (I) low-carbon aluminium killed steel (0,02wpct C 0,08wpct), (II) peritetic aluminium and silicon killed steel (0,09wpct C 0,15wpct); (III) extra-low-carbon, aluminium killed steel (C<35 ppm) were taken from the tundish distributor of a continuous casting caster for steel plates according to a procedure that minimizes re-oxidation of steel and/or pick up of liquid slag. The samples were inspected through the following microstructural techniques: optical microscopy, electronic microscopy, and electron microprobe. Were possible to feature present inclusion in each kind of steel according to morphology, size, amout and chemical composition.

Ao longo deste trabalho foi proposta uma nova rota de tratamento térmico para o aço AISI 52100, principal material utilizado na fabricação de rolamentos. Esta nova rota visa refinar a microestrutura de carbonetos presentes no material, com o objetivo de otimizar as propriedades mecânicas. Os tratamentos térmicos realizados conduziram a uma diminuição no tamanho dos carbonetos quando comparados com a amostra tradicional. Para medir a tenacidade à fratura evitando a dificuldade experimental de se nuclear pré-trincas em materiais frágeis, foi utilizada a metodologia Chevron, como formalizada na ASTM E-1304(97). Algumas das amostras submetidas a nova rota apresentaram maior tenacidade à fratura quando comparadas a amostra tratada na rota convencional. O material tratado na nova rota de tratamento térmico foi avaliado também em ensaio de impacto, usando-se corpos de prova Charpy de secção reduzida, sem entalhe. Os resultados obtidos mostraram que o material com carbonetos mais finos apresentavam menor energia absorvida no impacto quando comparados com a amostra tratada na rota convencional. Este comportamento a princípio contraditório foi explicado pela maior presença de sítios de nucleação na amostra com carbonetos mais finos. A maior densidade de sítios nas condições do ensaio de impacto conduziu a uma intensificação da nucleação de trincas, levando a uma menor energia absorvida durante o ensaio de impacto; este efeito ocorre mesmo quando o mecanismo de nucleação de trincas envolve a nucleação e coalescimento de microcavidades. Procurou-se fazer uma correlação entre a morfologia das superfícies de fratura obtidas no ensaio Chevron, o tamanho do carboneto das amostras e o micromecanismo atuante. Para amostras com superfície de fratura com aspecto fibroso foi associado o micromecanismo de fratura controlado por deformação. Para amostras com superfície de fratura com aspecto intergranular foi associado o micromecanismo de fratura controlado por tensão. / This work proposes a new heat treatment route for AISI 52100 steel, the most used material for bearings. The new route is designed so as to refine the carbides distribution in material, with the aim of increasing the fracture toughness. In order to measure the fracture toughness a Chevron notch methodology was used, as described in ASTM E-1304(97). Obtaining a static pre-crack on brittle materials is difficult and expensive; the Chevron notch methodology allows avoiding this difficulty. The heat treatments reduced the carbide sizes as compared with conventionally heat-treated steels. Some samples treated by this new route presented an increase in Chevron notch fracture toughness. The materials treated by the new heat treatment route were also tested in impact using a subsize Charpy specimen, without notch. Materials with fine carbides presented less dissipated energy in impact test then the material conventionally treated. This behavior is associated with the increase in number of carbide particles, as second phase particles are known to behave as sites for microvoid initiation and growth. The higher density of such sites presented in the material with fine carbides enhance this mechanism, lowering the dissipated energy measured in impact test. A correlation between fracture morphology, carbide size and fracture mechanisms was attempted. Samples with fine carbides presents fibrous transgranular fracture morphologies with strain controlled fracture micromechanism while samples with coarse carbides presented intergranular type morphologies with stress controlled micro-mechanism.

Nesse trabalho foi estudada uma técnica para a detecção de OHTC na água salina. Descobriu-se que certos complexos de rutênio em determinados valores de pH reagem com a molécula de OHTC e isto é detectável por espectrofotometria UV-Vis. Foram estudados os complexos fac-[RuCl2(S-DMSO)3(O-DMSO)] (complexo 1), {[(DMSO)2H][trans-RuCl4(DMSO)2]} (complexo 2) e cis-[RuCl2(bpy)2].2H2O (complexo 3). O complexo 1 possui um dos ligante (O-DMSO) que pode ser substituído pelo OHTC. Já o complexo 2 possui um dos ligantes (S-DMSO) na posição trans um ao outro, e o complexo 3 possui os 2 íons Cl- para tal finalidade. Determinou-se que o complexo 1 é viável, mesmo em presença de sais presentes na água do mar. Assim a reação foi realizada em função do tempo, variação do pH, temperatura e concentração de OHTC. Nos outros dois complexos os estudos foram realizados sem a variação da temperatura e concentração de OHTC. / p>In this work we studied a technique for detection of OHTC in water. It was discovered that complexes involving ruthenium, on determined pH values, react with the OHTC molecule and this is detectable by UV-VIS spectroscopy. The complexes fac-[RuCl2(S-dmso)3(O-dmso)] (complex 1), {[(DMSO)2H][trans-Ru(DMSO)2Cl4]} (complex 2), and cis-[RuCl2(bpy)2].2H2O (complex 3) were studied. The complex 1 present one position ( O - DMSO) which can be substituted by the OHTC. Additionally, the complex 2 present two ligands ( S- DMSO) trans between each other, and the complex 3 present two chloride ions for the same porpose of complex 1 respectively. It was determined that the complex 1 was able to react with OHTC even in presence of the salts present in sea water. Thereby, the reaction involving complex 1 and OHTC was monitored in function of the time, pH, temperature, and finally concentration of OHTC. On the other two complexes, the reaction was studied without variation of temperature and concentration of OHTC.