Thesis (D.P.H.)--University of Michigan, 1996.

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (p. [158]-162).

Thesis (M.S.)--Michigan State University. Packaging, 2008. / Title from PDF t.p. (viewed on Sept. 8, 2009) Includes bibliographical references (p. 132-144). Also issued in print.

Thesis (MSc)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.

Thesis (MSc)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 132-137). Also available on the Internet.

Master of Science / Department of Chemical Engineering / John R. Schlup / The cross-linking reaction of the polyimide Matrimid 5218 with ethylenediamine (EDA) in methanol was investigated using Fourier transform infrared (FTIR) spectroscopy. Peaks associated with breaking imide bonds and the formation of amide bonds were identified. Using an internal standard peak of 1014 cm⁻¹ allowed for quantitative analysis to be applied. The peak areas, calculated by slice area, were used for absorbance ratio analysis to follow the cross-linking reaction as a function of time. Lastly, the absorbance values for the decreasing peak 1718 cm⁻¹ were used to calculate the order of reaction for the reaction rate of the mechanism.

Orientador: Giselle Maria Marchi Baron / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-15T22:38:37Z (GMT). No. of bitstreams: 1 Voltarelli_FernandaRegina_D.pdf: 2059748 bytes, checksum: 5c76919f1c67fc154dd391b4ba4d28b4 (MD5) Previous issue date: 2010 / Resumo: O objetivo do presente estudo foi avaliar o efeito do tipo de fonte de luz (Lâmpada Halógena/HAL; Diodos emissores de luz/ LED), da distância de fotoativação (2, 4 e 6 mm) e do tempo de exposição (10, 20, 40 e 60s) sobre o grau de conversão (%) de cinco sistemas adesivos comerciais (Excite/EX; Adesivo de cobertura do sistema Clearfil Protect Bond /PB; Clearfil S3 Bond/S3; Single Bond Plus/SB; Adesivo de cobertura do sistema Scotchbond Multipurpose/SBMP). Cento e cinquenta amostras dos sistemas adesivos foram distribuídas em 30 grupos (n= 5) de acordo com o sistema adesivo, fonte de luz e distância da ponteira. Amostras de 3 µl foram gotejadas sobre um cristal de seleneto de zinco e, o grau de conversão/GC mensurado através de espectrofotômetro infravermelho por transformada de Fourier equipado com dispositivo de reflectância total atenuada (faixa espectral entre 1500-1800 cm-1; resolução de 8.0 cm-1; velocidade de deslocamento de 2,8 mm/s). Para EX, S3 e SB, jatos de ar foram aplicados durante 20s para auxiliar a evaporação do solvente. Imagens dos espectros obtidos antes da polimerização e imediatamente após completados os determinados tempos de exposição foram utilizadas para o cálculo do GC. Os valores de GC para distância e tempo de exposição foram analisados através de análise de variância para medidas repetidas no tempo com a metodologia PROC MIXED (?= 5%). Para EX e S3, HAL resultou em melhor grau de conversão em todos os tempos e distância de fotoativação. Quando fotoativados com HAL, SBMP, SB e PB demonstraram melhor grau de conversão a partir de 40s de fotoativação. Para S3, melhor grau de conversão foi observado após 20s de fotoativação. Quando fotoativados com LED, SBMP, SB e PB demonstraram melhor grau de conversão a partir de 20s de fotoativação. Para S3 melhor grau de conversão foi observado com o tempo máximo de fotoativação (60s). Para EX o efeito do tempo de fotoativação variou de acordo com a distância da ponta polimerizadora. Todas as variáveis (fonte de luz, distância e tempo de exposição) foram capazes de influenciar os valores de GC. Entretanto, tempos de exposição prolongados resultaram em significante melhoria do GC obtido para todos os sistemas adesivos testados. / Abstract: The aim of the present study was to evaluate the effect of the type of light curing unit (Halogen Lamp/HAL; Light Emitting Diodes/LED), of the light curing distance (2, 4 and 6 mm) and of the light curing exposure time (10, 20, 40 e 60s) on the degree of conversion (%) of five commercial adhesive systems (Excite/EX; Bond component from Clearfil Protect Bond /PB; Clearfil S3 Bond/S3; Single Bond Plus/SB; Bond component from Scotchbond Multipurpose/SBMP). Hundred and fifty samples were allocated into 30 groups (n = 5) according to the type of adhesive system, light curing unit and the distance from the light unit end point. Adhesive system samples of 3 ?l were dropped on the top of a zinc selenide crystal and the degree of conversion/DC was measured using Fourier Transform Infrared Spectroscopy equipped with Attenuated Total Reflectance attachment (spectral range between 1500-1800 cm-1; resolution of 8.0 cm-1; crosshead speed of 2.8 mm/s). For EX, S3 and SB, air drying streams for 20s were used to help solvent evaporation. Spectral images obtained before polymerization and immediately after each light curing exposure time were used for DC determination. DC values for the light curing distance and exposure time were analyzed using repeated measure ANOVA with PROC MIXED methodology (?= 5%). For EX and S3, HAL has shown improved degree of conversion for all light exposure times and for all light curing distances. When light cured with HAL, SBMP, SB and PB have shown improved degree of conversion following 40s of light curing exposure time. For S3, improved degree of conversion was observed after 20s of light curing exposure time. When light cured with LED, SBMP, SB and PB have shown improved degree of conversion following 20s of light curing exposure time. For S3, improved degree of conversion was observed with the ultimate light curing exposure time (60s). For EX, the effect of light curing exposure time varied according to the distance of the light curing end point. All variables (light curing unit, light curing distance and exposure time) were able to influence the DC values. However, longer exposure times resulted in significant improvement of the DC of all adhesive systems tested in this study. / Doutorado / Dentística / Doutor em Clínica Odontológica

Doctorat en Sciences / info:eu-repo/semantics/nonPublished

>Magister Scientiae - MSc / The growth of hydrogenated amorphous silicon carbide (a-SiC:H) thin films deposited by Hot- Wire Chemical Vapour Deposition (HWCVD) for solar cell applications has been studied. The films were characterized for structural properties using Fourier Transform Infrared Spectroscopy FTIR, Elastic Recoil Detection Analysis (ERDA), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Raman Spectroscopy (RS). A low temperature of the substrate heater maintained at 280 °C was used in this thesis due to the demand of low-cost solar cells based on cheap substrate that require deposition at such low temperatures. In this thesis, we showed that the structural properties of a-SiC:H films are dependent on the filament temperature and also on the CH4 gas flow rate. It was shown that in non-stoichiometric a-SiC:H, hydrogen content throughout the deposited films varies with depth. An attempt is done in this study to determine, for the first time the absorption strength of the C-Hn bonds in the 950 -1050 cm-1 band of the FTIR spectrum. Real-time ERDA was used to determine the hydrogen kinetics parameters in a single temperature ramp; a model based on the solution of the diffusion equation is used for this effect.