published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

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STATEMENT OF PROBLEM. Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic material has been reported to possess remarkably high flexural strength; however, after sintering zirconium dioxide (ZrO2) frameworks and fixed partial dentures, some may not fit properly when trying them on their master cast. PURPOSE. The objective of this study was to investigate joining fully sintered YTZ-P by various methods including adhesive cements or fusion with intervening materials. MATERIALS AND METHODS. 216 specimens were used in this study; bars were fabricated from Vita In-Ceram YZ blocks and three bars were joined using dental cements; RelyX Unicem 2 Clicker and Multilink Automix, or fusing them with VM9, Infusion Glass, Boron Oxide, Aluminum Oxide, LUDOX, Colloidal Zirconia and Mullite Zirconia. The load to failure in Newtons was determined using a 3-point bending test. RESULTS. Sandblasted bars for RelyX (64.38N, RelyX-A-Sb) and Multilink (48.58N, M-Sb) wasn’t significantly higher compared to as-sintered groups (45.87N, RelyX-A) and (34.69N, M-A). Coating the bars with Monobond-Plus had a significantly higher load to failure 123.22N, RelyX-A-MP and 136.06N, M-MP compared to as-sintered and sandblasted groups. VM9 at an end firing temperature (EFT) of 1200 °C was significantly higher (228.97N, V-5) compared to lower fusing temperatures. Glass at an end firing temperature of 1200 °C was significantly higher (460.32N, G-6) compared to lower fusing temperatures. Frit at an end firing temperature of 1200 °C was significantly higher (214.52N, F-6) compared to lower fusing temperatures. Optical microscopy showed that Glass group G-6 (1200°C, EFT) had a thickness range from .09 to 0.03 mm while for Glass-A (1050°C, EFT) it was 0.5 mm. CONCLUSIONS. Within the limitations of this study, we concluded that sandblasted bars didn’t significantly increase the means load to failure values compared to as-sintered groups. Coating the bars with Monobond-Plus had a significantly higher load to failure compared to as-sintered and sandblasted groups. VM9, Glass and Frit at an end firing temperature of 1200 °C showed significantly higher means load to failure compared to lower fusing temperature groups. / 2018-09-28T00:00:00Z

Cette recherche doctorale a pour objet la prostitution chinoise au Cameroun. L’approche anthropologique employée met en lumière les trajectoires de vie des prostituées chinoises, des clients et des prostituées camerounais, ainsi que l’organisation du marché du sexe dans les villes de Yaoundé et de Douala. À travers le prisme de ces différents acteurs, cette thèse fournit en premier lieu des éléments d’analyse sur la dette symbolique et financière des Chinoises. Ces deux formes de dette auxquelles elles sont contraintes les enferment dans le travail du sexe, présenté comme le seul moyen de remboursement par leurs créanciers. Cette étude révèle également l’influence des prostituées chinoises sur l’imaginaire de la sexualité des Camerounais, qui trouvent avec elles la possibilité de réaliser des pratiques sexuelles rejetées par les travailleuses du sexe et les femmes mariées camerounaises. / This doctoral research deals with Chinese prostitution in Cameroon. The anthropological approach used highlights life trajectories of Chinese sex workers, Cameroonian customers and prostitutes, and sex market organization in the cities of Yaoundé and Douala. Through the prism of these different actors, this thesis provides first of all analysis elements on symbolic and financial debts loads carried by Chinese women. Those both kind of debt they have to bear locks them into sex work, presented by their creditors as the only way to repayment. This study also reveals Chinese prostitutes’ influence on imaginary of sexuality of Cameroonian customers, who have the possibility to perform sexual practices usually rejected by Cameroonian sex workers.