Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Made available in DSpace on 2016-03-15T19:37:43Z (GMT). No. of bitstreams: 1 Priscila Romagnoli.pdf: 2103605 bytes, checksum: 61f6314f8d7400988a432b7a4793d4be (MD5) Previous issue date: 2013-01-24 / Photonic crystal fibers have been proposed as single-polarization (or polarizing) fibers with important applications being demonstrated, for example, in telecommunications, sensing and georeferencing. Although the vast majority of reported studies have focused on the numerical analysis of the performance of PCFs with specific and unconventional designs, post-processing PCFs also allows for great flexibility in altering the characteristics of guidance. In this work, the structure of a commercial, highly birefringent, PCF, with different holes diameters, has been locally changed using a tapering technique, which reduces the transverse dimensions of the fiber, with the application of pressure in the holes. This process was implemented to create 1-cm-long sections with a 66% reduction in their cross-sectional dimensions, through the application of pressure using two different schemes. It is numerically and experimentally shown that the two resulting structures are polarizing. In the first scheme, the same pressure is applied to all holes, resulting in a polarizing PCF at a wavelength of 633 nm, with an experimentally obtained polarization extinction ratio (PER) of 6.44 dB. In the second scheme, the applied pressure was different for the large and small holes, resulting in a polarizing PCF for the 1510-1590 nm wavelength range, with an experimentally obtained PER of more than 30 dB. Both the simplicity of the method and the resulting PER compares favorably with alternative methods to create polarizing conventional and photonic crystal fibers. / Fibras de cristal fotônico (PCFs, do inglês photonic crystal fibers) vêm sendo propostas como fibras polarizadoras, com importantes aplicações sendo demonstradas, por exemplo, em telecomunicações, sensoriamento e georreferenciamento. Apesar da vasta maioria dos trabalhos reportados analisarem numericamente o desempenho de PCFs com designs específicos e não convencionais, o pós-processamento em PCFs comerciais permite grande flexibilidade na alteração das características de guiamento. Neste trabalho, a estrutura de uma PCF altamente birrefringente comercial, com capilares de diferentes diâmetros, foi alterada localmente utilizando uma técnica de afilamento (tapering), que reduz as dimensões transversais da fibra, com aplicação de pressão nos capilares. Este processo foi implementado para criar seções de 1 ���� de extensão com uma redução nas dimensões transversais de 66%, aplicando-se pressão de duas formas diferentes. Demonstra-se numérica e experimentalmente que as duas estruturas resultantes são polarizadoras. Na primeira forma, aplicou-se uma única pressão em todos os capilares, resultando em uma PCF polarizadora no comprimento de onda de 633 ����, com uma razão de extinção de polarização (PER) experimentalmente obtida de 6,44 ����. Já na segunda forma aplicaram-se pressões diferentes nos capilares grandes e pequenos, o que resultou em uma PCF polarizadora para a faixa de comprimentos de onda que se estende de 1510 ���� a 1590 ����, com uma PER experimentalmente obtida superior a 30 ����. Tanto a simplicidade do método quanto a PER resultante possuem resultados positivos em comparação a métodos alternativos para a produção de fibras convencionais e fibras de cristal fotônico polarizadoras.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

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Social tillit är en central faktor i ett välfungerande samhälle och skapar förutsättningar för ekonomisktillväxt och sänkta transaktionskostnader. Att förstå vilka komponenter som kan bidra till nedbrytning avsocial tillit har därför stor betydelse för att kunna påverka samhällsutvecklingen. Syftet med denna uppsats är att identifiera och analysera drivkrafter och mekanismer som kan bryta ned social tillit i Sverige. En del forskare, däribland Robert Putnam, pekar på att etnisk mångfald på kort sikt kan bryta ned tillit. För att besvara uppsatsens syfte består studien av tre steg. Först identifieras tre komplikationer samt teser som utgör grunden för vår analysmodell. Dessa är modern informationsteknologi kan sprida misstro, identitet och polariserande drivkrafter kan styra individer att inte lita på andra samt begränsad rationalitet kan främja nedbrytningen av social tillit. Därefter genomfördes en omfattande litteraturstudie. Arbetet avslutades med en kvalitativ studie med sju semistrukturerade intervjuer där forskare och professorer fick granska den analysmodell som identifierats i studiens första steg. Komplikationerna analyseras med utgångspunkt i spelteorins förtroendespel. Även ett köns- ochgenusperspektiv inkluderas i analysen för att ta hänsyn till jämställdhetens centrala roll för ett fungerande högtillitssamhälle. Uppsatsen är explorativ och undersöker komplikationer som inte tidigare forskats kring. Därför önskade vi få kunskapsbidrag från professorer och forskare från olika discipliner för att skapa en helhetsbild av komplikationernas relevans för nedbrytningen av social tillit. Studien pekar på ett fortsatt högt och stabilt tillitsläge i Sverige och utöver komplikationerna visar studien att ekonomisk ojämlikhet och brist på gemenskap kan bidra till nerbrytning av social tillit. Denna hypotesgenererande uppsats ger upphov till tre hypoteser för fortsatt forskning. Att identitet och polariserande drivkrafter direkt kan förklara nedbrytning av social tillit genom att styra individer att inte lita på andra. Att modern informationsteknologi och begränsad rationalitet indirekt kan förklara nedbrytning av social tillit genom att sprida misstro respektive främja nedbrytningen. Att Putnams tes endast ger en förenklad bild av verkligheten och att etnisk mångfald inte ärdet största hotet för nedbrytning av social tillit. / Social trust is a key factor in a prosperous society and creates prerequisites for economic growth and reduced transaction costs. It is of significant value to understand which components contribute to the decomposition of social trust in order to impact social development. The purpose of this essay is toidentify and analyze forces and mechanisms that could decompose social trust in Sweden. Some researchers, including Robert Putnam, indicate that ethnic diversity could decompose trust in the short run. To answer the purpose of this study, the study consists of three stages. Three complications as well as theses were first chosen to create our analytical model. These are, that modern information technology could disseminate mistrust, that identity and polarizing forces could steer individuals not to trust others and that bounded rationality could promote the decomposition of social trust. After this stage, an extensive literature study was conducted. Lastly, a qualitative study with seven semi-structured interviews took place where professors and researchers were asked to review the analytical model that was conducted in the first stage of the study. The complications are analyzed from a game theoretic- and gender perspective. The study is explorative and examines complications that have not previously been examined or researched. As of this, we wish to gather knowledge from professors and researchers from different disciplines to create a holistic view of the complication's relevance on the decomposition of social trust. The study indicates a continuously high and stable state of trust in Sweden and, beyond the complications, the study shows that economic inequality and lack of community can contribute to the decomposition of social trust. This hypothesis generating essay originates three hypotheses for further research. That identity and polarizing forces could directly explain the decomposition of social trust by disseminating individuals not to trust others. That modern information technology and bounded rationality could indirectly explain the decomposition of social trust by steering mistrust respectively promoting the decomposition. That Putnam ́s thesis gives a simplified view of reality, and that ethnic diversity is not themost significant threat for the decomposition of social trust.

Gegenstand der vorliegenden Arbeit ist die Herstellung und Charakterisierung neuer sternförmiger Mesogene. Bei den aufgeführten Sternverbindungen, handelt es sich um Oligobenzoate, bestehend aus aromatischen Hydroxy- oder Aminocarbonsäuren, die durch Kupplungsreaktionen mit Dicylohexycarbodiimid, in einer konvergenten Synthesestrategie verknüpft wurden. Das besondere Augenmerk der Arbeit richtete sich auf die Charakterisierung der von den neuen Substanzen gebildeten Mesophasen, die mit Hilfe von Polarisationsmikrokopie, dynamischer Differenzialkalorimetrie und Röntgenstreuung erfolgte. Zur Aufklärung spezieller dreidimensionaler Strukturen wurden als zusätzliche Methoden die Rasterkraftmikroskopie angewandt und der Zirkulardichroismus untersucht.

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Στην εργασία αυτή αξιολογούνται οι πετρογραφικές και φυσικομηχανικές ιδιότητες που καθορίζουν την καταλληλότητα των ανθρακικών σχηματισμών του Νομού Αιτωλοακαρνανίας Δυτικής Ελλάδας,που ανήκουν στη ζώνη Ωλονού-Πίνδου ηλικίας Άνω Κρητιδικού.Σκοπός είναι να συσχετισθούν οι ιδιότητες αυτές,να προσδιοριστεί η συμπεριφορά των αργιλικών προσμίξεων και να καθορισθεί η καταλληλότητας τους,για χρήση τους ως αδρανή σε έργα οδοποιϊας.Δυο από τις δοκιμές που προσδιορίζουν την καθαρότητα των αδρανών είναι η δοκιμή ισοδύναμου άμμου και η δοκιμή μπλε του μεθυλενίου,τα αποτελέσματα των οποίων συσχετίστηκαν με τις πετρογραφικές και φυσικομηχανικές παραμέτρους των πετρωμάτων. / In this paper we evaluate the petrographic and physicomechanical properties which determine the suitability of carbonate formations of Aitoloakarnania Western Greece , in Olonos - Pindos unit Cretaceous age.The objective is to relate these properties to determine the behavior of clay impurities and determine the suitability for use as aggregates in road construction.Two of the tests that used to determine the purity of the aggregates is the sand equivalent and methylene blue, the results of which were associated with the petrographic and physico-mechanical parameters of rocks .

Gegenstand der vorliegenden Arbeit ist die Herstellung und Charakterisierung neuer sternförmiger Mesogene. Bei den aufgeführten Sternverbindungen, handelt es sich um Oligobenzoate, bestehend aus aromatischen Hydroxy- oder Aminocarbonsäuren, die durch Kupplungsreaktionen mit Dicylohexycarbodiimid, in einer konvergenten Synthesestrategie verknüpft wurden. Das besondere Augenmerk der Arbeit richtete sich auf die Charakterisierung der von den neuen Substanzen gebildeten Mesophasen, die mit Hilfe von Polarisationsmikrokopie, dynamischer Differenzialkalorimetrie und Röntgenstreuung erfolgte. Zur Aufklärung spezieller dreidimensionaler Strukturen wurden als zusätzliche Methoden die Rasterkraftmikroskopie angewandt und der Zirkulardichroismus untersucht.