171 |
Syntheses, Characterization, Physical and Biological Properties of Long-chain, Water-soluble, Dendritic AmphiphilesWilliams, André Arvin 08 April 2008 (has links)
In this project, we have designed and synthesized a new series of long-chain, water-soluble, dendritic, anionic amphiphiles [3CAmn, RCONHC(CH₂CH₂COOH)₃, R= CnH2n+1] to alleviate the low aqueous solubility of fatty acids. The dendritictricarboxlyato headgroup improves aqueous solubility and allows us to measure the intrinsic biological activity of our amphiphiles without the potential hindrance of low aqueous solubility. The aqueous solubilities of the anionic amphiphiles have been measured and were vastly higher than that of fatty acids. For example, 3CAm17 (1700 μM at pH 7.2) has much better aqueous solubility than the C₁₈ fatty acid analog (<<1 micromol at pH 7.4).
Following the determination of aqueous solubility, both anionic and nonionic amphiphiles were tested against a wide variety of microorganisms. The anionic amphiphiles were mostly active against Candida albicans (4.4 microgram/mL), Saccharomyces cerevisiae (4.4 μg/mL), and Mycobacterium smegmatis (18 microgram/mL) and exhibited modest activity against both Gram-negative (71–280 microgram/mL) and Gram-positive bacteria (36– >6300 microgram/mL). With the exception of Neisseria gonorrhoeae (9.8 microgram/mL), the nonionic amphiphiles were mostly minimally active or inactive against Gram-negative bacteria (630–5000 microgram/mL). The nonionic amphiphiles were similarly inactive against fungi (625–5000 microgram/mL). However, the nonionic amphiphiles exhibited good activity against M. smegmatis (20 microgram/mL) and exhibited the best activity against Grampositive bacteria, such as MRSA (22 microgram/mL), Staphylococcus aureus (20 microgram/mL), and Micrococcus luteus (20 microgram/mL).
The anionic and nonionic amphiphiles were also tested for possible spermicidal and anti-human immunodefiency virus (HIV) activity. The anionic amphiphiles exhibited anti-HIV activity (EC₅₀, 73–340 microgram/mL), but lacked spermicidal activity. The series had comparable anti-HIV activity to the commercial product N-9 (80 microgram/mL). Except 3CAm13, all anionic amphiphiles (1.4–4) had better selectivity indices than that of N-9 (0.9). The nonionic amphiphiles exhibited both anti-HIV (44–67 microgram/mL) and spermicidal activity (226–2000 microgram/mL). The nonionic amphiphile were more spermicidal and antiviral than Nonoxynol-9.
In addition to biological activity, we determined whether the anionic amphiphiles could be utilized as corrosion inhibitors or ore flotation enhancers. The anionic amphiphiles formed stable thin films on silver oxide that were resistant to ethanol washings. We also measured the water contact angles of the anionic amphiphiles on mineral surfaces [apatite (95°), calcite (92°)]. / Ph. D.
|
172 |
Synthesis, Characterization, and Antimicrobial Activity of Water-soluble, Tri-carboxylato AmphiphilesSugandhi, Eko Winny 05 March 2007 (has links)
Many previous studies of biological activity in a homologous series of amphiphiles have shown a cut-off effect, where the biological activity increases with an increase in chain length, after which the activity plateaus or weakens. One factor suspected to cause this problem is solubility issues. We have designed several series of very hydrophobic, water-soluble amphiphiles to overcome this problem. Three homologous series containing mobile hydrophobic moieties and two series of epimers containing rigid cholestane moieties have been synthesized; the hydrophobic moiety is connected to the first-generation, Newkome-type dendron via a ureido linker. We have demonstrated that as tris(triethanolammonium) salts, these amphiphiles show excellent solubility in water. The solubilities in aqueous triethanolamine solution of the three series containing mobile hydrophobic moieties are 19,500 to 25,700 μM depending on the formula weight of the homolog, while those containing rigid cholestane moieties are 18,900 and 17,400 μM.
Having eliminated the solubility issue, the antimicrobial activity against a broad spectrum of microorganisms has been screened. We have demonstrated that the antimicrobial activity depends on the amphiphile-series, species, chain-length, or epimer specificities, as well as hydrophobicity. The one-tailed, tri-carboxylato amphiphiles are generally better than the other series, with two exceptions. First, the two-tailed tri-carboxylato amphiphiles, <b>3CUr1(11)₂</b> and <b>3CUr1(12)₂</b>, are more active against <i>Cryptococcus neoformans</i>; in fact, both amphiphiles (MICs are 6.9 and 7.2 μM, respectively) are considered to display good antifungal activity. Second, amphiphile <b>3CUr-β-cholestane</b>, whose MIC is 27 μM, is more active against <i>Staphylococcus aureus</i>. Overall, these new tri-carboxylato amphiphiles only exhibit moderate activity with two promising leads.
Furthermore, we have demonstrated the intrinsic activity (MIC₀) of the one-tailed, tri-carboxylato amphiphile series (<b>3CUrn</b>) against <i>Mycobacterium smegmatis</i>. All the MIC₀s observed are at least 8-fold lower than the corresponding CMCs. Amphiphile <b>3CUr16</b> is the most active; the MIC₀ is 100-fold smaller than the CMC. With this consideration, we have suggested that the mechanism of action of the antimycobacterial activity in amphiphile <b>3CUr16</b> is not related to detergency. / Ph. D.
|
173 |
Electron microscopic localization of tagged proteins in the yeast S. cerevisiae spliceosomal U4/U6.U5 trisnRNP / Elektronenmikroskopische Lokalisierung markierter Proteine im spleißosomalen U4/U6.U5 tri-snRNP aus der Hefe S. cerevisaeHäcker, Irina 02 July 2008 (has links)
No description available.
|
174 |
Proposta de modelo de decisão para avaliação de fornecedores baseado no ELECTRE TRI para categorização e na teoria dos conjuntos fuzzy para a modelagem da incerteza e hesitação de múltiplos tomadores de decisão / Proposal of decision model for supplier evaluation based on ELECTRE TRI for categorization and fuzzy sets theory for the modeling of uncertainty and hesitation of multiple decision makersGalo, Nadya Regina 19 April 2018 (has links)
A gestão eficaz dos processos que envolvem os fornecedores tem grande influência na melhoria do desempenho organizacional, sendo, portanto, fundamental para desenvolver capacidades das operações de produção que podem gerar vantagem competitiva, tais como qualidade, preço e tempo de entrega. A gestão de fornecedores inclui as atividades de qualificação, seleção, avaliação e desenvolvimento de fornecedores, além da alocação de pedido quando múltiplas fontes de fornecimento são selecionadas. A qualificação é um processo importante para assegurar que os fornecedores atendam requisitos mínimos de desempenho e, idealmente, deve ser realizada com métodos não compensatórios de categorização das alternativas. Entretanto, na literatura há poucos estudos que abordam a qualificação de fornecedores. Dentre aqueles que abordam, a maioria utiliza técnicas multicritério que são compensatórias e de ordenação. Outros aspectos importantes da gestão de fornecedores é a possível presença vários tomadores de decisão, caracterizando um processo de tomada de decisão em grupo, além da subjetividade de alguns critérios que gera incerteza nos julgamentos e hesitação. Ao se considerar essas questões na gestão de fornecedores, nenhuma pesquisa na literatura apresenta uma abordagem que contemple todos as características simultaneamente. Além disso, poucas pesquisas abordam os processos da gestão de fornecedores sob uma perspectiva integrada. Com vista a estas lacunas, esta pesquisa tem por objetivo a proposição de dois modelos de decisão que consideram os processos de qualificação, seleção e avaliação de fornecedores, em um cenário de tomada de decisão em grupo, considerando a incerteza e hesitação. Os modelos propostos têm por finalidade elicitar as preferências, agregar os julgamentos e categorizar os fornecedores. O primeiro modelo utiliza a representação linguística Triangular Hesitant Fuzzy Sets, para lidar com a hesitação nos julgamentos dos tomadores de decisão, além da técnica ELECTRE TRI para a categorização dos fornecedores. O segundo modelo se baseia na aplicação representação linguística Intuitionistic Fuzzy Sets para modelar a hesitação na parametrização das variáveis linguísticas e no ELECTRE TRI para a categorização. A elicitação é realizada com o uso do Fuzzy Delphi combinado com operadores de agregação do Triangular Hesitant Fuzzy Sets e Intuitionistic Fuzzy Sets. Os modelos de decisão foram detalhados e implementados no Matlab©. Após a proposição dos métodos, dois casos ilustrativos, obtidos a partir da coleta em campo, foram apresentados para analisar o desempenho dos modelos. Os casos ilustrativos mostraram resultados de categorização consistentes, especialmente para o procedimento pessimista do ELECTRE TRI. Testes com a hesitação nos julgamentos dos tomadores de decisão evidenciaram a importância da modelagem da hesitação, pois ela tem o potencial de alterar a categorização das alternativas. Testes com os parâmetros do ELECTRE TRI, confirmaram o efeito não compensatório da técnica e que a variação do nível de corte tem o potencial de tornar a categorização mais flexível. Assim, esta tese apresenta uma revisão de literatura sobre os processos de gestão de fornecedores e sobre tomada de decisão multicritério e em grupo, a proposição de métodos de apoio à tomada de decisão, casos ilustrativos para ilustrar o modelo, análises de sensibilidade dos métodos, além das conclusões e propostas para trabalhos futuros. / Effective management of the processes that involving suppliers has a major influence on improving organizational performance and is therefore fundamental to develop production operations capabilities that can generate competitive advantage, such as quality, price and delivery time. Supplier management includes qualification, selection, evaluation and development of suppliers, as well as allocation of orders when multiple sources of supply are selected. Qualification is an important process to ensure that suppliers meet minimum performance requirements and ideally must be performed with non-compensatory methods of categorization. However, in the literature there are few studies that consider the process of supplier qualification. Among the studies that consider the qualification, most use multicriteria techniques that are compensatory and for ranking. Other important aspects of supplier management are the possible presence of several decision makers, characterizing a process of group decision making, as well as the subjectivity of some criteria that generates uncertainty in judgments and hesitation. When considering these issues in supplier management, none of the studies found in the literature presents an approach that contemplates all features simultaneously. In addition, few researches deal with supplier management processes from an integrated perspective. In view of these gaps, this research aims to propose two decision models that consider the processes of qualification, selection and evaluation of suppliers, in a scenario of group decision making, considering the uncertainty and hesitation. The proposed models have the purpose the elicitation of the preferences, the aggregation of the judgments and the categorization of the suppliers. The first model uses the linguistic representation Triangular Hesitant Fuzzy Sets, to deal with the hesitation in the judgments of the decision makers, in addition to the ELECTRE TRI technique for the categorization of the suppliers. The second model is based on the application of the linguistic representation Intuitionistic Fuzzy Sets to model the hesitation in the parameterization of the linguistic variables and in the ELECTRE TRI for categorization. Elicitation is performed with the use of Fuzzy Delphi combined with aggregation operators of the Triangular Hesitant Fuzzy Sets and Intuitionistic Fuzzy Sets. The decision models were detailed and implemented in Matlab©. Two illustrative cases, obtained from the field collection, were presented to analyze the performance of the models. The illustrative cases showed consistent categorization results, especially for the pessimistic procedure of ELECTRE TRI. Tests with hesitation in the judgments of decision makers highlighted the importance of modeling hesitation, since it has the potential to change the categorization of alternatives. Tests with the ELECTRE TRI parameters confirmed the non-compensatory effect of the technique and that the variation of the cut level has the potential to make categorization more flexible. Thus, this thesis presents a review of the literature on supplier management processes and on multicriteria and group decision making, the proposition of methods to support decision making, illustrative cases to illustrate the model, method sensitivity analyzes, besides the conclusions and proposals for future works.
|
175 |
Proposta de modelo de decisão para avaliação de fornecedores baseado no ELECTRE TRI para categorização e na teoria dos conjuntos fuzzy para a modelagem da incerteza e hesitação de múltiplos tomadores de decisão / Proposal of decision model for supplier evaluation based on ELECTRE TRI for categorization and fuzzy sets theory for the modeling of uncertainty and hesitation of multiple decision makersNadya Regina Galo 19 April 2018 (has links)
A gestão eficaz dos processos que envolvem os fornecedores tem grande influência na melhoria do desempenho organizacional, sendo, portanto, fundamental para desenvolver capacidades das operações de produção que podem gerar vantagem competitiva, tais como qualidade, preço e tempo de entrega. A gestão de fornecedores inclui as atividades de qualificação, seleção, avaliação e desenvolvimento de fornecedores, além da alocação de pedido quando múltiplas fontes de fornecimento são selecionadas. A qualificação é um processo importante para assegurar que os fornecedores atendam requisitos mínimos de desempenho e, idealmente, deve ser realizada com métodos não compensatórios de categorização das alternativas. Entretanto, na literatura há poucos estudos que abordam a qualificação de fornecedores. Dentre aqueles que abordam, a maioria utiliza técnicas multicritério que são compensatórias e de ordenação. Outros aspectos importantes da gestão de fornecedores é a possível presença vários tomadores de decisão, caracterizando um processo de tomada de decisão em grupo, além da subjetividade de alguns critérios que gera incerteza nos julgamentos e hesitação. Ao se considerar essas questões na gestão de fornecedores, nenhuma pesquisa na literatura apresenta uma abordagem que contemple todos as características simultaneamente. Além disso, poucas pesquisas abordam os processos da gestão de fornecedores sob uma perspectiva integrada. Com vista a estas lacunas, esta pesquisa tem por objetivo a proposição de dois modelos de decisão que consideram os processos de qualificação, seleção e avaliação de fornecedores, em um cenário de tomada de decisão em grupo, considerando a incerteza e hesitação. Os modelos propostos têm por finalidade elicitar as preferências, agregar os julgamentos e categorizar os fornecedores. O primeiro modelo utiliza a representação linguística Triangular Hesitant Fuzzy Sets, para lidar com a hesitação nos julgamentos dos tomadores de decisão, além da técnica ELECTRE TRI para a categorização dos fornecedores. O segundo modelo se baseia na aplicação representação linguística Intuitionistic Fuzzy Sets para modelar a hesitação na parametrização das variáveis linguísticas e no ELECTRE TRI para a categorização. A elicitação é realizada com o uso do Fuzzy Delphi combinado com operadores de agregação do Triangular Hesitant Fuzzy Sets e Intuitionistic Fuzzy Sets. Os modelos de decisão foram detalhados e implementados no Matlab©. Após a proposição dos métodos, dois casos ilustrativos, obtidos a partir da coleta em campo, foram apresentados para analisar o desempenho dos modelos. Os casos ilustrativos mostraram resultados de categorização consistentes, especialmente para o procedimento pessimista do ELECTRE TRI. Testes com a hesitação nos julgamentos dos tomadores de decisão evidenciaram a importância da modelagem da hesitação, pois ela tem o potencial de alterar a categorização das alternativas. Testes com os parâmetros do ELECTRE TRI, confirmaram o efeito não compensatório da técnica e que a variação do nível de corte tem o potencial de tornar a categorização mais flexível. Assim, esta tese apresenta uma revisão de literatura sobre os processos de gestão de fornecedores e sobre tomada de decisão multicritério e em grupo, a proposição de métodos de apoio à tomada de decisão, casos ilustrativos para ilustrar o modelo, análises de sensibilidade dos métodos, além das conclusões e propostas para trabalhos futuros. / Effective management of the processes that involving suppliers has a major influence on improving organizational performance and is therefore fundamental to develop production operations capabilities that can generate competitive advantage, such as quality, price and delivery time. Supplier management includes qualification, selection, evaluation and development of suppliers, as well as allocation of orders when multiple sources of supply are selected. Qualification is an important process to ensure that suppliers meet minimum performance requirements and ideally must be performed with non-compensatory methods of categorization. However, in the literature there are few studies that consider the process of supplier qualification. Among the studies that consider the qualification, most use multicriteria techniques that are compensatory and for ranking. Other important aspects of supplier management are the possible presence of several decision makers, characterizing a process of group decision making, as well as the subjectivity of some criteria that generates uncertainty in judgments and hesitation. When considering these issues in supplier management, none of the studies found in the literature presents an approach that contemplates all features simultaneously. In addition, few researches deal with supplier management processes from an integrated perspective. In view of these gaps, this research aims to propose two decision models that consider the processes of qualification, selection and evaluation of suppliers, in a scenario of group decision making, considering the uncertainty and hesitation. The proposed models have the purpose the elicitation of the preferences, the aggregation of the judgments and the categorization of the suppliers. The first model uses the linguistic representation Triangular Hesitant Fuzzy Sets, to deal with the hesitation in the judgments of the decision makers, in addition to the ELECTRE TRI technique for the categorization of the suppliers. The second model is based on the application of the linguistic representation Intuitionistic Fuzzy Sets to model the hesitation in the parameterization of the linguistic variables and in the ELECTRE TRI for categorization. Elicitation is performed with the use of Fuzzy Delphi combined with aggregation operators of the Triangular Hesitant Fuzzy Sets and Intuitionistic Fuzzy Sets. The decision models were detailed and implemented in Matlab©. Two illustrative cases, obtained from the field collection, were presented to analyze the performance of the models. The illustrative cases showed consistent categorization results, especially for the pessimistic procedure of ELECTRE TRI. Tests with hesitation in the judgments of decision makers highlighted the importance of modeling hesitation, since it has the potential to change the categorization of alternatives. Tests with the ELECTRE TRI parameters confirmed the non-compensatory effect of the technique and that the variation of the cut level has the potential to make categorization more flexible. Thus, this thesis presents a review of the literature on supplier management processes and on multicriteria and group decision making, the proposition of methods to support decision making, illustrative cases to illustrate the model, method sensitivity analyzes, besides the conclusions and proposals for future works.
|
176 |
Etude de la projection plasma sous très faible pression - torches et procédé de dépôt / Study of thermal spray for plasma torch under cery low pressureZhu, Lin 06 December 2011 (has links)
Au cours de la dernière décennie, la technologie de projection à la torche à plasmasous très faible pression (VLPPS) (inférieure à 10 mbar) a attiré l’attention denombreux chercheurs car ce procédé permet d’envisager la possibilité de réaliser desdépôts de structure voisine de celle des dépôts en phase vapeur avec une cinétiqueproche de celle de la projection thermique classique. Cette technologie vise donc àévaporer totalement ou partiellement des poudres afin de déposer des revêtementsdenses avec une structure colonnaire ou mixte.Le travail effectué dans cette étude à consisté à étudier et à développer des moyenspour assurer la fusion et l’évaporation de matériaux céramiques en vue d’élaborer desrevêtements de haute qualité et à caractériser les propriétés de ces revêtements.Dans une première approche des dépôts denses et homogènes de zircone stabilisée àl’yttrine (YSZ) ont été obtenus sur un substrat « inox » en utilisant des torches àplasma « classiques » de type F100 et F4 sous très faible pression (1 mbar) en utilisantde façon originale un principe d’injection axiale via l’alimentation en gazplasmagènes. Un spectromètre d’émission optique a été utilisé pour analyser lespropriétés du jet de plasma et notamment apprécier le taux d’évaporation du matériau.La composition et la microstructure des dépôts ont été caractérisées par diffraction desrayons X et microscopie électronique à balayage. Les résultats ont montré que lapoudre YSZ a été partiellement évaporée et que les dépôts obtenus disposent d’unemicrostructure hybride composée de « splats » formés par des particules fondues etune « matrice » (en faible quantité) résultant de la condensation de vapeurs provenantde l’évaporation des particules surchauffées.Afin de tenter d’augmenter le taux de vaporisation, l’anode de la torche F100 a étéallongée et un dispositif d’arc transféré complémentaire a été réalisé afin d’éleverl’énergie du jet de plasma et de favoriser l’échange thermique. Les effets de cedispositif sur les propriétés du jet de plasma ont été évalués par spectrométried’émission optique et calcul de la température électronique. Des dépôts de YSZ etd’alumine (Al2O3) ont été élaborés à la pression de 1 mbar. Les dépôts de YSZ ontaffiché une microstructure hybride similaire à celle obtenue précédemment alors quepour les dépôts d’alumine, seul un dépôt lamellaire « classique » a été observé. Lacapacité d’évaporation est donc restée limitée. La microstructure, les propriétésmécaniques et les propriétés de résistance aux chocs thermiques des dépôts de YSZont été étudiées plus en détail et comparées avec celle de dépôts réalisés dans desconditions plus classiques. Une tenue améliorée en termes de résistance aux cyclagesthermiques a notamment été observée.Afin de répondre aux attentes en matière de niveau de densité de puissance du jet lelaboratoire s’est équipé d’une une nouvelle torche à plasma tri-cathode expérimentaleélaborée par la société AMT. Cette torche a été modélisée et testée dans un premiertemps en conditions atmosphériques, révélant une limitation importante du rendementde projection. A partir de ces premiers résultats expérimentaux une nouvellegéométrie de buse a été proposée afin d’améliorer le rendement de projection. Il aalors été constaté que le rendement de la projection avait été considérablementaugmenté par cette modification et que la microstructure du dépôt était également plusfavorable. Ce travail devra maintenant se poursuivre par l’intégration de cette torche dans l’enceinte sous pression réduite. / During the last decade, very low pressure plasma spraying (VLPPS) technology(below 10 mbar) attracted attention because it could allow to produce coatings with astructure similar to that of vapor deposited materials (PVD) with kinetics close to thatof thermal spray. This technology aims to fully or partially evaporate the feedstockmaterials in order to build rapidly dense, thin, and columnar coatings.The work during this thesis preparation was thus devoted to the study anddevelopment of tools and techniques allowing fusion and evaporation of ceramicmaterials in order to obtain high quality deposits with new performance and then tocharacterize the properties of those deposits. In a first approach dense and homogeneous yttria-stabilized zirconia (YSZ) coatingswere deposited successfully on a stainless steel substrate using “classical” plasmaspray torches such as F100 and F4 under very low pressure (1 mbar) by means ofusing an original way of introducing the feedstock material in the core of the plasmajet via the plasma gas port. Optical emission spectroscopy was used to analyze theproperties of the plasma jet and especially to observe the feedstock materialevaporation rate. The phase composition and the microstructure of the coatings werecharacterized by X-ray diffraction and scanning electron microscopy. Results showedthat the YSZ powder was partially evaporated and that the coatings possessed aduplex microstructure which was composed of splats formed by the impingement ofmelted particles and a little amount of a matrix formed by the condensation of thevapor emitted by overheated particles.In order to try and increase the evaporation rate, a home-made transferred arc nozzlewas made and mounted on a F100 plasma torch in order to enhance the energy levelof the plasma jet and then to increase thermal exchanges. The effects of thetransferred arc nozzle on the plasma jet properties were evaluated by optical emissionspectroscopy and electron temperature calculation. YSZ and alumina (Al2O3) coatingsWere elaborated using such a nozzle below 1 mbar. It was found that the YSZ coatingsdisplayed a duplex microstructure similar to that obtained in the previous experiments.However, no vapor condensation could be observed in the case of the Al2O3 coatingsindicating that the evaporation capacity of the system remained limited.The microstructure, the mechanical properties and the thermal shock resistance of theYSZ coatings were studied in more details and compared to that of deposits madeusing classical thermal spray routes. An enhanced resistance to thermal shock couldthus be observed for the coatings with a duplex structure.In order to find a solution for a substantial increase in the energy density of theplasma jet, the laboratory commissioned a novel experimental tri-cathode plasmatorch made to the AMT Company. This new torch was modeled and first testedunder atmospheric conditions, which revealed a poor spray yield. Following thosefirst experimental results, a modified nozzle was designed. As a result, the sprayefficiency was considerably increased and the coating fabricated by the tri-cathodetorch displayed a better microstructure. Now this work has to be pursued with theintegration of this torch in the low pressure spray tank.
|
177 |
Prot?tipo de uma unidade com tri-gera??o de energia para utiliza??es remotas: aplica??o de m?dulo secondutivo gerador termoel?tricoSantos, Ildefonso Martins dos 27 June 2007 (has links)
Made available in DSpace on 2014-12-17T14:57:39Z (GMT). No. of bitstreams: 1
IldefonsoMS.pdf: 1793001 bytes, checksum: 8b7c737ca595a5f30c4e9de306d3fe97 (MD5)
Previous issue date: 2007-06-27 / The generation for termoeletricity is characterized as a solid process of conversion of thermal energy (heat) in electric without the necessity of mobile parts. Although the conversion process is of low efficiency the system presents high degree of trustworthiness and low requisite of
maintenance and durability. Its principle is based on the studies of termogeneration carried through by Thomas Seebeck in 1800. The frank development of the technologies of solid state for termoeletricity generation, the necessity of the best exploitation of the energy, also with incentive
the cogeneration processes, the reduction of the ambient impact allies to the development of modules semiconductors of high efficiency, converge to the use of the thermoeletric generation through components of solid state in remote applications. The work presents the development,
construction and performance evaluation of an prototype, in pilot scale, for energy tri-generation aiming at application in remote areas. The unit is composed of a gas lamp as primary source of energy, a module commercial semiconductor for thermoelectric generation and a shirt for production of the luminosity. The project of the device made compatible a headstock for adaptation in the gas lamp, a hot source for adaptation of the module, an exchanger of to be used
heat as cold source and to compose first stage of cogeneration, an exchanger of tubular heat to compose second stage of cogeneration, the elaboration of a converter dc-dc type push pull, adequacy of a system of acquisition of temperature. It was become fullfilled assembly of the
prototype in group of benches for tests and assay in the full load condition in order to evaluate its efficiency, had been carried through energy balance of the unit. The prototype presented an electric efficiency of 0,73%, thermal of 56,55%, illumination of 1,35% and global of 58,62%. The developed prototype, as the adopted methodology of assay had also taken care of to the considered objectives, making possible the attainment of conclusive results concerning to the
experiment. Optimization in the system of setting of the semicondutor module, improvement in the thermal insulation and design of the prototype and system of protection to the user are suggestions to become it a commercial product / A gera??o por termoeletricidade caracteriza-se como um processo s?lido de convers?o de energia t?rmica (calor) em el?trica sem a necessidade de partes m?veis. Embora o processo de convers?o seja de baixa efici?ncia o sistema apresenta alto grau de confiabilidade e baix?ssimos requisitos de manuten??o e durabilidade. Seu princ?pio ? baseado nos estudos de termogera??o realizados por Thomas Seebeck em 1821. O franco desenvolvimento das tecnologias de estado s?lido para gera??o de termoeletricidade, a necessidade do melhor aproveitamento da energia, inclusive com incentivo a processos de cogera??o, a redu??o do impacto ambiental aliados ao desenvolvimento de m?dulos semicondutores de alta efici?ncia, convergem para o uso da gera??o termoel?trica atrav?s de componentes de estado s?lido em
aplica??es remotas. O trabalho apresenta o desenvolvimento, constru??o e avalia??o de performance de um prot?tipo, em escala piloto, para tri-gera??o de energia visando aplica??o em ?reas remotas. A unidade ? composta de um lampi?o a g?s combust?vel como fonte prim?ria de energia, um m?dulo semicondutor comercial para gera??o termoel?trica e uma camisa para produ??o da luminosidade. O projeto do dispositivo compatibilizou um cabe?ote para adapta??o
no lampi?o, uma fonte quente para adapta??o do m?dulo, um trocador de calor para ser utilizado como fonte fria e compor o 1? est?gio de cogera??o, um trocador de calor tubular para compor o 2? est?gio de cogera??o, a elabora??o de um conversor cc-cc tipo push pull, adequa??o de um
sistema de aquisi??o de temperatura. Realizou-se a montagem do prot?tipo em bancada para testes e ensaio na condi??o de carga plena a fim de avaliar a sua efici?ncia, sendo realizado
balan?o de energia da unidade. O prot?tipo apresentou uma efici?ncia el?trica de 0,73%, t?rmica de 56,55%, de ilumina??o de 1,35% e global de 58,62%. O prot?tipo desenvolvido, como tamb?m a metodologia de ensaio adotada atenderam aos objetivos propostos, possibilitando a obten??o de resultados conclusivos acerca do experimento. Otimiza??o no sistema de fixa??o do m?dulo semicondutor, melhoramento na isola??o t?rmica e design do prot?tipo e sistema de prote??o ao usu?rio s?o sugest?es para torn?-lo um produto comercial
|
178 |
Création et exploitation d'un corpus trilingue du tourisme (italien/français/anglais) en vue de la réalisation d'une base de données lexicale informatisée / Creation and exploitation of a trilingual tourism corpus (Italian, French, English) for the realisation of a lexical electronic stored databasePiccato, Mariangela 23 July 2012 (has links)
Au cours des dernières années, le secteur touristique a été caractérisé par toute une série de changements fondamentaux. L’un de ces changements, certainement le plus important, a été le fait d’être considéré aujourd’hui comme l’activité productive capable de faire tourner l’économie d’un pays entier.Notre mémoire de recherche se situe à l’intersection de la terminologie thématique, de la linguistique de corpus et du traitement automatique des langues.Dans le premier chapitre du travail que nous allons présenter, nous chercherons à introduire aux domaines d’études théoriques sur lesquels notre recherche s’appuie.Premièrement, on traitera de la linguistique de corpus et on examinera les différentes catégories de corpus existantes. On mettra l’accent sur deux notions fondamentales dans la conception de l’outil corpus en général et dans la création de notre corpus en particulier : représentativité et contexte. Au sein du discours touristique, la représentativité, d’un côté, se relie au caractère spécial de notre micro-langue ; le contexte, de l’autre, révèle la pluralité des sous-domaines qui composent ce technolecte à mi-chemin entre la langue générale et la langue spécialisée.Dans le deuxième chapitre, nous présenterons le corpus thématique trilingue (CTT) que nous avons créé préalablement à la rédaction de la thèse proprement dite.Avant tout, on fournira les indications théoriques et pragmatiques nécessaires pour réaliser un corpus trilingue en langue de spécialité : la collecte des textes, l’homogénéisation des échantillons textuels repérés et l’annotation. Au cours de ce chapitre, nous présenterons Alinea, l’instrument qu’on a utilisé pour l’alignement de textes recueillis et pour la consultation simultanée des traductions trilingues. Dans le troisième et dernier chapitre, on passera à l’interrogation du corpus créé. Sur la base d’un terme pris comme exemple, le terme ville, on lancera la recherche dans le CTT. Ensuite, on analysera les collocations les plus usitées contenant le mot ville.En guise de conclusion de notre mémoire, nous présenterons une annexe consacrée à notre glossaire trilingue comme résultat de notre exploration de la chaîne terminologique qu’on aura analysée précédemment. Pour conclure, l’objectif général de notre étude sera d’explorer la chaîne de gestion terminologique à travers la création d’un glossaire trilingue dans le domaine du tourisme. Notre orientation méthodologique de caractère sémasiologique impliquera ainsi au moins quatre objectifs spécifiques :• créer un corpus trilingue du tourisme (CTT), capable d’attester des usages en contexte des termes.• extraire des termes en utilisant des techniques diverses, telle que l’étude fréquentielle des éléments du corpus.• vérifier les données obtenues et les compléter à l’aide de ressources externes.• répertorier et décrire l’ensemble des termes sous forme d’un glossaire trilingue à sujet touristique (GTT). / Our study concerns the language of tourism from a lexicographical perspective.Exploiting the web we realized a corpus ad hoc. This corpus is composed by about 10.000 texts in three languages (French, Italian and English), aligned using “Alinea”.Starting from terminological extraction, we analysed some collocations at the aim to create a trilingual and tri-directional glossary.We chose this subject according to the increasing importance taken from tourism economy in the world.Our study fields are thematic terminology, corpus linguistics and automatic language treatment.The first chapter presents the study field of our research. First of all, we introduced to corpus linguistics presenting the different categories of corpus and pointing out our attention on two main notions: representativeness and context.Therefore, we explained the link between Language for Special Purposes and tourism discourse as a Specialized Discourse.In the second chapter, we showed the trilingual thematic corpus we created during our researches. We described the main steps to create a corpus: collection of texts, cleaning and annotation.In this chapter, we gave a particular attention to the presentation of “Alinea”.Finally, the third chapter is a study of frequent collocations with the term “town” (ville).The annexes present the glossary as well as the methodological principals we followed in the redaction.
|
179 |
Integration von Multi-Gate-Transistoren auf Basis einer 22 nm-TechnologieBaldauf, Tim 10 January 2014 (has links)
Die kontinuierliche Skalierung der planaren MOSFETs war in den vergangenen 40 Jahren der Schlüssel, um die Bauelemente immer kleiner und leistungsfähiger zu gestalten. Hinzu kamen Techniken zur mechanischen Verspannung, Verfahren zur Kurzzeitausheilung, die in-situ-dotierte Epitaxie und neue Materialien, wie das High-k-Gateoxid in Verbindung mit Titannitrid als Gatemetall. Jedoch erschwerten Kurzkanaleffekte und eine zunehmende Streuung der elektrischen Eigenschaften die Verkleinerung der planaren Transistoren erheblich. Somit gelangten die planaren MOSFETs mit der aktuellen 28 nm-Technologie teilweise an die Grenzen ihrer Funktionalität. Diese Arbeit beschäftigt sich daher mit der Integration von Multi-Gate-Transistoren auf Basis einer 22 nm-Technologie, welche eine bessere Steuerfähigkeit des Gatekontaktes aufweisen und somit die Fortführung der Skalierung ermöglichen. Zudem standen die Anforderungen eines stabilen und kostengünstigen Herstellungsprozesses als Grundvoraussetzung zur Übernahme in die Volumenproduktion stets mit im Vordergrund. Die Simulationen der Tri-Gate-Transistoren stellten dabei den ersten Schritt hin zu einer Multi-Gate-Technologie dar. Ihre Prozessabfolge unterscheidet sich von den planaren Transistoren nur durch die Formierung der Finnen und bietet damit die Möglichkeit eines hybriden 22 nm-Prozesses. Am Beispiel der Tri-Gate-Transistoren wurden zudem die Auswirkungen der Kristallorientierung, der mechanischen Verspannung und der Überlagerungseffekte es elektrischen Feldes auf die Leistungsfähigkeit von Multi-Gate-Strukturen analysiert. Im nächsten Schritt wurden Transistoren mit vollständig verarmten Kanalgebieten untersucht. Sie weisen aufgrund einer niedrigen Kanaldotierung eine Volumeninversion, eine höhere Ladungsträgerbeweglichkeit und eine geringere Anfälligkeit gegenüber der zufälligen Dotierungsfluktuation auf, welche für leistungsfähige Multi-Gate-Transistoren entscheidende Kriterien sind. Zu den betrachteten Varianten zählen die planaren ultradünnen SOI-MOSFETs, die klassischen FinFETs mit schmalen hohen Finnen und die vertikalen Nanowire-Transistoren. Anschließend wurden die Vor- und Nachteile der verschiedenen Transistorstrukturen für eine mittel- bis langfristige industrielle Nutzung betrachtet. Dazu erfolgte eine Analyse der statistischen Schwankungen und eine Skalierung hin zur 14 nm-Technologie. Eine Zusammenfassung aller Ergebnisse und ein Ausblick auf die mögliche Übernahme der Konzepte in die Volumenproduktion schließen die Arbeit ab.:Symbol- und Abkürzungsverzeichnis
1 Einleitung
2 Grundlagen und Entwicklung der CMOS-Technologie
2.1 Planare Transistoren
2.1.1 Theoretische Grundlagen von MOSFETs
2.1.2 Skalierung und Kurzkanalverhalten planarer Transistoren
2.1.3 Mechanische Verspannung von Silizium
2.1.4 Techniken zur mechanischen Verspannung
2.2 Multi-Gate-Transistoren
2.2.1 Multi-Gate-Strukturen
2.2.2 Überlagerungseffekte
2.2.3 Quanteneffekte
2.3 Stand der Technik
3 Grundlagen der Simulation
3.1 Prozesssimulation
3.1.1 Abscheiden und Abtragen von Schichten
3.1.2 Implantation
3.1.3 Thermische Ausheilung mit Diffusion
3.2 Bauelementesimulation
3.2.1 Grundgleichungen und Ladungsträgertransport
3.2.2 Bandlückenverengung
3.2.3 Generation und Rekombination
3.2.4 Ladungsträgerbeweglichkeit
3.2.5 Effekte der mechanischen Verspannung
3.2.6 Ladungsträgerquantisierung
3.3 Kalibrierung der Modellparameter
3.3.1 Prozessparameter
3.3.2 Modellparameter
4 Planare Transistoren auf Basis einer 22 nm-Technologie
4.1 Transistoraufbau
4.1.1 Replacement-Gate-Prozess
4.1.2 In-situ-dotierte Source-Drain-Gebiete
4.1.3 Haloimplantation
4.1.4 Elemente der mechanischen Verspannung
4.2 Charakterisierung des elektrischen Verhaltens
4.2.1 Stationäres Verhalten
4.2.2 Gatesteuerung und Kurzkanaleffekte
4.2.3 Dynamisches Verhalten
5 Tri-Gate-Transistoren
5.1 Prozessintegration und Transistoraufbau
5.1.1 Anforderungen an hochintegrierte Schaltkreise
5.1.2 Hybride CMOS-Technologie
5.1.3 Strukturierung der Finne
5.1.4 Geometrieabhängiges Dotierungsprofil
5.2 Charakterisierung des elektrischen Verhaltens
5.2.1 Stationäres Verhalten
5.2.2 Kurzkanaleffekte und Gatesteuerung
5.2.3 Eckeneffekt
5.2.4 Eckenimplantation
5.2.5 Finnengeometrie
5.2.6 Dynamisches Verhalten
5.3 Optimierung der Tri-Gate-Struktur
5.3.1 Gestaltung der epitaktischen Source-Drain-Gebiete
5.3.2 Mechanisch verspanntes Isolationsoxid
5.3.3 Substratorientierung
6 Transistoren mit vollständig verarmtem Kanal
6.1 Ultra-Dünne-SOI-MOSFETs
6.1.1 Prozessintegration
6.1.2 Charakterisierung des elektrischen Verhaltens
6.2 FinFETs
6.2.1 Prozessintegration
6.2.2 Charakterisierung des elektrischen Verhaltens
6.3 Vertikale Nanowire-MOSFETs
6.3.1 Prozessintegration
6.3.2 Strukturierung des Aktivgebiets
6.3.3 Charakterisierung des elektrischen Verhaltens
6.3.4 Asymmetrisches Dotierungsprofil
6.3.5 Mechanische Verspannung
7 Skalierung und statistische Schwankungen der Strukturen
7.1 Skalierung zur 14 nm-Technologie
7.1.1 Leistungsfähigkeit
7.1.2 Kurzkanalverhalten und Steuerfähigkeit
7.2 Statistische Schwankungen
7.2.1 Impedanz-Feld-Methode
7.2.2 Zufällige Dotierungsfluktuation
7.2.3 Fixe Ladungen im Oxid
7.2.4 Metall-Gate-Granularität
7.2.5 Geometrische Variationen
7.2.6 Kombination der Störquellen
8 Zusammenfassung und Ausblick
Anhang
Literaturverzeichnis
Danksagung
Acknowledgement / Within the past 40 years the continuous scaling of planar MOSFETs was key to shrink the devices and to improve their performance. Techniques like mechanical stressing, rapid thermal annealing and in-situ doped epitaxial growing as well as novel materials, such as high-k-gate-oxide in combination with titanium nitride as metal-gate, has been introduced. However, short-channel-effects and increased scattering of electrical proper-ties significantly complicate the scaling of planar transistors. Thus, the planar MOSFETs gradually reached their limits of functionality with the current 28 nm technology node. For that reason, this work focuses on integration of multi-gate transistors based on a 22 nm technology, which show an improved gate control and allow a continuous scaling. Furthermore, the requirements of a stable and cost-efficient process as decisive condition for mass fabrication were always taken into account. The simulations of the tri-gate transistors present the first step toward a multi-gate technology. The process sequence differs from the planar one solely by a fin formation and offers the possibility of a hybrid 22 nm process. Also, the impact of crystal orientation, mechanical stress and superposition of electrical fields on the efficiency of multi-gate structures were analyzed for the tri-gate transistors. In a second step transistors with fully depleted channel regions were studied. Due to low channel doping they are showing a volume inversion, a higher carrier mobility and a lower sensitivity to random doping fluctuations, which are essential criteria for powerful multi-gate transistors. Reviewed structure variants include planar ultra-thin-body-SOI-MOSFETs, classic FinFETs with a tall, narrow fins and vertical nanowire transistors. Then advantages and disadvantages of the considered transistor structures have been observed for a medium to long term industrial use. For this purpose, an analysis of statistical fluctuations and the scaling-down to 14 nm technology was carried out. A summary of all results and an outlook to the transfer of concepts into mass fabrication complete this work.:Symbol- und Abkürzungsverzeichnis
1 Einleitung
2 Grundlagen und Entwicklung der CMOS-Technologie
2.1 Planare Transistoren
2.1.1 Theoretische Grundlagen von MOSFETs
2.1.2 Skalierung und Kurzkanalverhalten planarer Transistoren
2.1.3 Mechanische Verspannung von Silizium
2.1.4 Techniken zur mechanischen Verspannung
2.2 Multi-Gate-Transistoren
2.2.1 Multi-Gate-Strukturen
2.2.2 Überlagerungseffekte
2.2.3 Quanteneffekte
2.3 Stand der Technik
3 Grundlagen der Simulation
3.1 Prozesssimulation
3.1.1 Abscheiden und Abtragen von Schichten
3.1.2 Implantation
3.1.3 Thermische Ausheilung mit Diffusion
3.2 Bauelementesimulation
3.2.1 Grundgleichungen und Ladungsträgertransport
3.2.2 Bandlückenverengung
3.2.3 Generation und Rekombination
3.2.4 Ladungsträgerbeweglichkeit
3.2.5 Effekte der mechanischen Verspannung
3.2.6 Ladungsträgerquantisierung
3.3 Kalibrierung der Modellparameter
3.3.1 Prozessparameter
3.3.2 Modellparameter
4 Planare Transistoren auf Basis einer 22 nm-Technologie
4.1 Transistoraufbau
4.1.1 Replacement-Gate-Prozess
4.1.2 In-situ-dotierte Source-Drain-Gebiete
4.1.3 Haloimplantation
4.1.4 Elemente der mechanischen Verspannung
4.2 Charakterisierung des elektrischen Verhaltens
4.2.1 Stationäres Verhalten
4.2.2 Gatesteuerung und Kurzkanaleffekte
4.2.3 Dynamisches Verhalten
5 Tri-Gate-Transistoren
5.1 Prozessintegration und Transistoraufbau
5.1.1 Anforderungen an hochintegrierte Schaltkreise
5.1.2 Hybride CMOS-Technologie
5.1.3 Strukturierung der Finne
5.1.4 Geometrieabhängiges Dotierungsprofil
5.2 Charakterisierung des elektrischen Verhaltens
5.2.1 Stationäres Verhalten
5.2.2 Kurzkanaleffekte und Gatesteuerung
5.2.3 Eckeneffekt
5.2.4 Eckenimplantation
5.2.5 Finnengeometrie
5.2.6 Dynamisches Verhalten
5.3 Optimierung der Tri-Gate-Struktur
5.3.1 Gestaltung der epitaktischen Source-Drain-Gebiete
5.3.2 Mechanisch verspanntes Isolationsoxid
5.3.3 Substratorientierung
6 Transistoren mit vollständig verarmtem Kanal
6.1 Ultra-Dünne-SOI-MOSFETs
6.1.1 Prozessintegration
6.1.2 Charakterisierung des elektrischen Verhaltens
6.2 FinFETs
6.2.1 Prozessintegration
6.2.2 Charakterisierung des elektrischen Verhaltens
6.3 Vertikale Nanowire-MOSFETs
6.3.1 Prozessintegration
6.3.2 Strukturierung des Aktivgebiets
6.3.3 Charakterisierung des elektrischen Verhaltens
6.3.4 Asymmetrisches Dotierungsprofil
6.3.5 Mechanische Verspannung
7 Skalierung und statistische Schwankungen der Strukturen
7.1 Skalierung zur 14 nm-Technologie
7.1.1 Leistungsfähigkeit
7.1.2 Kurzkanalverhalten und Steuerfähigkeit
7.2 Statistische Schwankungen
7.2.1 Impedanz-Feld-Methode
7.2.2 Zufällige Dotierungsfluktuation
7.2.3 Fixe Ladungen im Oxid
7.2.4 Metall-Gate-Granularität
7.2.5 Geometrische Variationen
7.2.6 Kombination der Störquellen
8 Zusammenfassung und Ausblick
Anhang
Literaturverzeichnis
Danksagung
Acknowledgement
|
180 |
Phase space methods in finite quantum systemsHadhrami, Hilal Al January 2009 (has links)
Quantum systems with finite Hilbert space where position x and momentum p take values in Z(d) (integers modulo d) are considered. Symplectic tranformations S(2ξ,Z(p)) in ξ-partite finite quantum systems are studied and constructed explicitly. Examples of applying such simple method is given for the case of bi-partite and tri-partite systems. The quantum correlations between the sub-systems after applying these transformations are discussed and quantified using various methods. An extended phase-space x-p-X-P where X, P ε Z(d) are position increment and momentum increment, is introduced. In this phase space the extended Wigner and Weyl functions are defined and their marginal properties are studied. The fourth order interference in the extended phase space is studied and verified using the extended Wigner function. It is seen that for both pure and mixed states the fourth order interference can be obtained.
|
Page generated in 0.0378 seconds