La localisation de sources (en champ lointain ou en champ proche) et l'estimation des temps de retard ont de nombreuses applications pratiques. Pour localiser une source en champ lointain à partir d'un réseau de capteur, seule la direction d'arrivée (DDA) de la source est nécessaire. Quand les sources se situent dans une situation de champ proche, le front d'onde du signal est sphérique et deux paramètres sont nécessaires pour localiser les sources : la direction d'arrivée et la distance entre la source et le réseau de capteurs. Dans cette thèse, on se focalise sur la localisation de sources (en champ lointain et en champ proche) ainsi sur l'estimation des temps de retard dans le contexte où les signaux sont cohérents, mélangés et avec un faible nombre de réalisation. Tout d'abord, nous proposons de combiner la théorie de la méthode SVR (Support vector regression qui est une méthode de régression à base d'apprentissage supervisée) avec la théorie de la prédiction linéaire avant-arrière. La méthode proposée, appelée FBLP-SVR, est développée pour deux applications : la localisation de sources en champ lointain et l'estimation des temps de retard des échos radar en champ lointain. La méthode développée est évaluée par des simulations et des expérimentations. Nous proposons également une méthode de localisation de sources en champ proche dans le contexte où les signaux sont cohérents et mélangés. La méthode proposée est basée sur une technique de focalisation, de moyennage en sous-bande et sur une méthode à sous-espaces pour l'estimation des DDAs. Ensuite, les distances entre les sources et le réseau de capteur sont estimées avec la méthode du maximum de vraisemblance. / Source localization (in far-field or in nearfield) and time-delay estimation have many practical applications. To locate a far-field source from a sensor array, only the direction of arrival (DOA) of the source is necessary. When the sources are in a nearfield situation, the wavefront of the signal is spherical and two parameters are needed to locate the sources: the direction of arrival and the distance between the source and the sensors. In this thesis, we focus on the localization of sources (both in far-field and nearfield) as well as the estimation of time-delay in the context where the signals are coherent, overlapped and with a small number of snapshots. First, we propose to combine the theory of the SVR method (support vector regression, which is a supervised learning-based regression method) with the theory of forward-backward linear prediction (FBLP). The proposed method, called FBLP-SVR, is developed for two applications: far-field source localization and time-delay estimation by using ground penetrating radar. The proposed method is evaluated by simulations and experiments. We also propose a near-field source localization method in the context where the signals are coherent and overlapped. The proposed method is based on a focusing technique, a spatial smoothing preprocessing, and a subspace method in the estimation of DOA. Then, the distances between the sources and sensors are estimated with the maximum likelihood method.

abstract: Water-soluble, adenosine triphosphate (ATP)-stabilized palladium nanoparticles have been synthesized by reduction of palladium salt in the presence of excess ATP. They have been characterized by electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and X-ray diffraction in order to determine particle size, shape, composition and crystal structure. The particles were then subsequently attached to a glassy carbon electrode (GCE) in order to explore their electrochemical properties with regard to hydrogen insertion in 1 M sodium hydroxide. The particles were found to be in the size range 2.5 to 4 nm with good size dispersion. The ATP capping ligand allowed the particles to be air-stable and re-dissolved without agglomeration. It was found that the NPs could be firmly attached to the working electrode via cycling the voltage repeatedly in a NP/phosphate solution. Further electrochemical experiments were conducted to investigate the adsorption and absorption of hydrogen in the NPs in 1 M sodium hydroxide. Results for cyclic voltammetry experiments were consistent with those for nanostructured and thin-film palladium in basic solution. Absorbed hydrogen content was analyzed as a function of potential. The maximum hydrogen:Pd ratio was found to be ~0.7, close the theoretical maximum value for β phase palladium hydride. / Dissertation/Thesis / M.S. Chemistry 2013

Empresas de base tecnológica (EBT) requerem a existência ou desenvolvimento de capacidades empresariais que determinarão a sustentabilidade do negócio. As incubadoras de empresas têm sido consideradas como um dos meios possíveis para que as EBTs atinjam um nível de desenvolvimento dessas capacidades que podem assegurar, após a incubação, sua permanência e progresso no mercado. Entretanto, é importante determinar se os objetivos para os quais as incubadoras foram criadas estão sendo atingidos e em que grau. O estudo apresenta pesquisa que buscou avaliar impacto do processo de incubação de empresas, medindo o desenvolvimento de capacidades em três dimensões: inovação, solidez financeira e capacidade gerencial. Estas dimensões, foram mensuradas em dezesseis EBTs do setor de informática do Estado do Rio Grande do Sul em dois grupos de empresas com características similares: o grupo de empresas pós-incubadas e o grupo de empresas não-incubadas. O método utilizado é o estudo de múltiplos casos em um desenho quase-experimental. Para a coleta de dados, o principal sócio de cada empresa respondeu a uma entrevista semi-estruturada e a um questionário fechado. A análise dos dados revelou que as empresas pós-incubadas demonstraram ser mais inovadoras e têm gestores melhor capacitados na área gerencial mas, no entanto, possuem menor solidez financeira. Por outro lado, as empresas não-incubadas são menos inovadoras e seus gestores têm menor capacitação gerencial, mas apresentam maior solidez financeira, indicada pela relação favorável entre receita e despesa e uma receita mensal regular. Os resultados deste estudo, com suas limitações de tamanho da amostra, evidenciam que o processo de incubação tem o impacto esperado no desenvolvimento de EBTs.

Made available in DSpace on 2014-06-12T17:42:23Z (GMT). No. of bitstreams: 2 arquivo9572_1.pdf: 2264538 bytes, checksum: fb8807fe5a1100d6a87cdef1becea760 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2005 / Na ultima decada, o uso e desenvolvimento de tecnicas de otimizacao tem se dado com aplicacoes cada vez mais realisticas, associados com problemas praticos de engenhari- a. Isto em geral, envolve calculos extensos e podem alcancar um custo computacional invi- avel para obtencao de um projeto 6timo. Como uma conseqilencia, otimizacoes baseadas em aproximacoes (HAFTA et all, 2004) tem recebido muita atencao, uma vez que em geral produzem calculos velozes para o desenvolvimento de funcoes/derivadas requeridas repeti- damente pelos otimizadores, alem de eliminar os ruidos numericos comumente observados em funcoes/gradientes obtidos por procedimentos numericos. Neste trabalho foi desenvolvida uma metodologia para otimizacao atraves de apro- ximacao. Para este fim sera considerado o Metodo da Base Reduzida ou (Reduced Based Method - RBM). 0 RBM e uma projecao do tipo Galerkin em um espaco de aproximacao de baixa ordem que contem solucoes para o problema de interesse em pontos selecionados do espaco de projeto. 0 procedimento combina dois aspectos, a saber: uma aproximacao com precisao e uma melhoria na eficiencia computacional. Enquanto o uso de uma trans- formacao de decomposicao da matriz de rigidez e vetor de carregamento do problema con- vencional (computacionalmente caro) e requerido para a melhoria da eficiencia computa- cional, a verificacao da precisao para o metodo pode ser abordada com a consideracao de um estimador de erro a posteriori. Essa medicao de precisao e geralmente ausente nas me- todologias de aproximacao empregadas na literatura. Neste metodo, o estimador de erro e calculado diretamente na grandeza de interesse. Um procedimento que emprega uma rela- xacao na equacao original do erro mostrou-se uma estrategia eficiente para o calculo de tais estimadores. No RBM utiliza-se uma estrategia de separabilidade do par1metro. Todos os calcu- los sao conduzidos em um dominio fixo denominado de referencia ou computacional. Transformacoes geometricas entre o dominio real e computacional sao conduzidas e inseri- das nas equacoes governantes de cada problema especifico. Isto, junto com a decomposicao dos termos da rigidez e de forca permite o desenvolvimento de um algoritmo para imple- mentacao computacional do metodo dividido em dois estagios denominados off-line e on- line. 0s calculos off-line sao conduzidos somente uma vez e usados subseqilentemente no estagio on-line para cada novo par1metro desejado. Com isso, para cada novo projeto, fun- coes, estimadores de erro e gradientes sao obtidos rapidamente. 0 desenvolvimento de uma ferramenta eficiente e agil conduzida atraves do procedimento do RBM o torna bem atrati- vo para prop6sitos de otimizacao. Esta dissertacao mostra aplicacoes do metodo acima descrito em problemas elasti- cos lineares , termicos e acoplados (termo-elastico), bidimensionais. Essas aplicacoes nos trazem um desafio inerente ao Metodo da Base Reduzida que e uma dependencia complexa do par1metro relacionado as transformacoes de um dominio real e computacional que ficam embutidos na matriz de rigidez e vetor de carregamento. Foi desenvolvido um algoritmo de otimizacao de forma , Structural Shape Optimi- zation (SS0) integrando definicoes geometricas, analise estrutural (e/ou termica), estimado- res de erro, analise de sensibilidade e otimizacao. Neste contexto, o RBM abrange os m6- dulos de analise estrutural (e/ou termica) e de sensibilidade. Um algoritmo de programacao seqilencial quadratica, Sequential Quadratic Programming (SQP (Powell,1978) e usado como otimizador. Uma versao do algoritmo SS0 utilizando o procedimento convencional, isto e a analise estrutural (e/ou termica) via o Metodo dos Elementos Finitos (MEF) foi tambem desenvolvido com o objetivo de comparar os resultados obtidos via RBM. Varios exemplos utilizando ambas estrategias serao investigados com o objetivo de se verificar a efetividade e robustez dos procedimentos desenvolvidos.

Magister Scientiae Dentium - MSc(Dent) / Objectives:Substances leaching from denture- base polymers have been associated with cytotoxicity and allergic reactions. This study examined the effect of polishing,mixing ratios, water immersion temperatures and different thicknesses on the sorption and solubility of a heat-polymerized, denture-base polymer. The effect of different water immersion temperatures on the flexural strength of the denture base, was tested as well. The next component of this study, is the testing of the most significant sorption and solubility findings on in vitro cell viability. Materials and Methods:Disc shaped specimens from a heat-polymerized, denture-base polymer (Vertex®) were prepared, based on ISO 1567 specifications for sorption and solubility testing, following the manufacturers’ instructions. The following tests were performed: 1) Sorption and solubility of two groups (n = 12 each) of polished and unpolished discs were established and compared by means of the Mixed procedure; 2) Sorption and solubility of three groups (n = 12 each) with different mixing ratios were compared by means of the Mixed procedure; 3) Four groups (n = 14 each) were immersed in water at different temperatures, sorption and solubility were compared by means of pairwise comparison and the Median test; 4) Specimens with different thicknesses (n = 36) were compared, again, by means of pairwise comparison and the Median test; 5) To test the influence of different water-soaking temperatures on the flexural strength of the disc, strips were prepared from the disc used in test no. 3. The flexural strength was compared, by means of the Median test; 6) To test the influence of no postpolymerization treatment, polishing and water immersion on the cytotoxicity of mouse fibroblast cells, (n = 9) for each test group, were prepared. A preliminary test was performed beforehand, over a period of 24 hours, up to a maximum period of four weeks. The Balb/c 3T3 mouse fibroblast cells were cultured and incubated for 24 hours in Eagles medium. Eluates prepared from the disc and medium without any disc (control) replaced the medium. Cytotoxicity was assessed by MTT-assay. Optical density values were obtained at 24 and 48 hour intervals. The data was analyzed by means of the Means procedure.Results:In the entire thesis, the data was analyzed using SAS on a 0.01 probability level.Between polished and unpolished groups, no significant difference in water sorption (p> 0.01) was found, but there was a difference in solubility (p<0.01).Different mixing ratios did not alter sorption (p = 0.34) or solubility (p = 0.68).However, a difference (p<0.01) in sorption and solubility was found among the different temperature and thickness groups. Soaking the denture base in water at different temperatures did not alter its flexural strength (p = 0.48). Cell viability levels were noted in all the experimental groups in the MTT assay test. The analysis was a two-factor study, with one factor being the group, and the other, being time. The interaction between these factors was found to be significant, indicating that the effect of the groups varied by time (and vice versa).Conclusion:The processes of the soaking in warm water and the polishing of a denture-base polymer, reduce its solubility. Therefore, it is recommended that dentures are soaked in warm water before polishing. Within the limits of this study, the mixing ratios may be changed without affecting sorption or solubility. As solubility increases within the increasing denture-base thickness, it is recommended that unnecessarily thick dentures be avoided.Short- and long-term exposure to eluates of a PMMA, has a negative effect on cell viability. For water-stored and polished discs, this effect is time-dependent, with a higher viability for 48 hours’, than for 24 hours eluates. Polishing is associated with lower solubility. At 24 hours, the polished discs, indeed, had a lower cytotoxic effect than the untreated discs: it may be recommended that dentures be polished on the fitting surface as well.The cytotoxic potential of PMMA-eluates appears to fluctuate over time.

<p>In organic synthesis, controlling stereochemistry can be a challenge whether you are working with small molecules or larger natural products. Current chiral bases, such as Sparteine, are difficult to make or expensive to purchase. Their other drawback is that many chiral bases only can access one stereochemical configuration, not both. In the work presented here, progress has been made towards developing a chiral base from an amino acid derivative, L-valine. The chiral base has been fully synthesized. The use of the amino acid starting material, allows for us to make both the R and S selective amino acid. Efforts are being made to determine the efficacy of the base to control stereochemistry. </p>

Es wurden Übergangsmetallkomplexe der Metalle Rhodium, Palladium und Platin synthetisiert und unter anderem in Bezug auf ihre Reaktivität als Lewis-Basen untersucht. Hierfür wurden Lewis-Addukte mit Aluminiumtrichlorid mit experimentellen und quantenchemischen Methoden umfassend untersucht. Des Weiteren wurde die Reaktivität von verschiedenen Fluorboranen gegnüber Lewis-basischen Übergangsmetallkomplexen untersucht. Auch konnte die Reaktivität von Münzgruppenmetall-Halogen-Bindungen gegenüber Lewis-Basen analysiert werden. So konnten nicht nur Insertionsprodukte, sondern auch kationische Metal-Only Lewis Pairs, unter anderem anhand von Einkristallröntgenstrukturanalysen und Dichte-Funktional-Theorie Rechnungen, untersucht werden. / Several transition metal complexes of the metals rhodium, palladium and platinum were synthesized and investigated in means of their reactivity as Lewis bases. For this purpose, Lewis adducts with aluminum trichloride were examined by experimental and quantum-chemical methods. Furthermore, the reactivity of fluoroboranes towards Lewis-basic transition metal complexes was investigated. Additionally, the reactivity of coinage group metal-halogen bonds towards platinum centred Lewis bases was analysed. Hereby, insertion products as well as cationic Metal-Only Lewis Pairs were fully characterized, for example by single crystal X-ray structure analysis and by density functional theory calculations.

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Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Base isolated buildings are well known to provide enhanced performance due to minimized accelerations and decreased interstory drifts. However, the reduced demands are obtained at the expense of large displacements at the isolation layer. This study investigates an innovative system, termed ‘dual isolation’, which applies two layers of isolation, one at the base and one mid-story to resolve this issue. An analytical solution for the equation of motion of the proposed system is developed based on linear isolation theory. This creates a foundation to assess the behavior of various types of seismic protection systems and to select the damping, mass and frequency ratio that leads to an optimal dual isolation design. Time history responses of the dual isolation system with viscous damping are compared to those of a conventional isolation counterpart to examine the effectiveness of the system. The system reduces first floor displacements by 40% on average, while the roof displacement is increased by roughly 15%. This results in reduced design forces for the structure. In addition, accelerations, especially above the second isolation layer, are significantly decreased. By reducing story shears and accelerations, the dual isolation system limits damage to both structural and nonstructural systems and components, thereby increasing global system performance. / Thesis / Master of Applied Science (MASc)