Thesis (M. Sc.)--Carleton University, 2005. / Includes bibliographical references. Also available in electronic format on the Internet.

Thèses (Ph.D.)--Université de Sherbrooke (Canada), 1998. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

Orientador: Caio Cezar Randi Ferraz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T21:47:13Z (GMT). No. of bitstreams: 1 Santos_IvanaLins_M.pdf: 4446919 bytes, checksum: 906c2bb88c7bbc1591d2d43d0c214552 (MD5) Previous issue date: 2005 / Resumo: O presente trabalho avaliou, in vitra, a capacidade de remoção da smear layer das paredes dos canais radiculares após o preparo químico-mecânico realizado com diferentes substâncias químicas auxiliares. Selecionou-se 54 dentes humanos unirradiculares, com canais retos e ápices formados, divididos em grupos seguindo o protocolo de irrigação: G1: NaOCI 5,25% + EDTA 17%; G2: solução fisiológica 0,9%; G3: clorexidina (CLX) gel 2% pH neutro + solução fisiológica 0,9%; G4: CLX gel 2% pH neutro + solução fisiológica 0,9% + EDTA 17%; G5: CLX gel a 2% pH ácido + solução fisiológica 0,9% e G6: CLX gel a 2% pH ácido + solução fisiológica 0,9% + EDTA 17%. Os grupos foram instrumentados utilizando técnica manual híbrida, sendo analisadas quatro áreas distintas em cada terço do canal radicular: apical, médio e cervical, através do microscópio eletrônico de varredura (MEV) atribuindo escores de 0 a 3 de acordo com Gaberogllio & Becce (1994), considerando a capacidade de limpeza de cada substância. A análise estatística utilizou o software SPSS (Statistical Package for Social Sciences) e o teste não paramétrico de Mann-Whitney. Concluímos que a combinação das soluções de NaOCI a 5,25% e irrigação final com EDTA a 17% foi mais efetiva na remoção da smear layer das paredes dos canais radiculares quando comparado com as demais soluções testadas (p<0,05). O uso do gluconato de clorexidina gel a 2% com pH ácido + EDTA a 17% foi mais efetivo apenas quando comparado com a solução fisiológica e o gel de gluconato de clorexidina a 2% com pH neutro + solução fisiológica (p<0,05). A clorexidina gel neutra + solução fisiológica foi a que apresentou pior condição de limpeza das paredes dos canais radiculares. O terço apical apresentou condições de limpeza estatisticamente inferiores, independente das soluções testadas / Abstract: This in vitro study evaluted the effects of 2% chlorhexidine gel with acid pH on smear layer removal after chemomechanical debridement as endodontic irrigating solution. Fifty-four single-root extracted of human teeth were separated into six groups: G1: 5.25% NaOCI + 17% EDTA; G2: saline solution; G3: 2% chlorhexidine gel (CHX) neutral pH + saline solution; G4: 2% CHX gel neutral pH + saline solution + EDTA 17%; G5: 2% CHX gel acid pH + saline solution and G6: 2% CHX gel acid pH + Saline solution + EDTA 17%. After instrumentation using the respective irrigants, the root canais were examined by scanning electron microscopy in four differents areas in each third of the canal: apical, middle and carona!. The areas photographed were evaluated according to the rating system developed by Gaberoglio & Becce (1994). The data were analyzed using the Mann-Whitney test to determine whether there was any significant difference in the ability of the irrigating regimens to remove the smear layer. In the coronal and middle thirds, 5.25% NaOCI + 17% EDTA effectively removes the smear layer when compared with the others substances (p<0.05).In the coronal third, the 2% CHX gel acid pH + EDTA 17% were statistically more effective in removing the smear layer than with saline solution; 2% CHX gel neutral; 2% CHX gel acid pH (p<0.05). In the midlle third, this irrigant had the same result, except when compared with the 2% CHX gel acid pH alone. In the apical third, the difference was significant and better to the group flushed with 5.25% NaOCI + 17% EDTA compared with saline solution and 2% CHX gel neutral pH + saline solution / Mestrado / Endodontia / Mestre em Clínica Odontológica

The inorganic chemistries of coal and petroleum differ because of their disparate geologic environments of formation, the physical state of the fuels, and the type and quantity of minerals and organic compounds in the fuels. Commercial coals typically contain 2 to 25% ash (average ~ 10%) while petroleums contain 0.003 to 0.07% ash (average ~ 0.01 %). Globally averaged, coal ash is dominated by Si, Fe, Ca, AI, and S, whereas petroleum ash contains significant quantities of V, Ni, S, Fe, Ca, Na, K, Mg, Si and AI. This larger number of important elements causes petroleum combustion slags to have more complex phase assemblages. The high vanadium contents of petroleum-based combustion feedstocks yield numerous crystalline V -oxides with stoichiometric amounts of Ca, Fe, Mg, AI, Ni andlor Na in the resulting slags. Slightly lower nickel contents yield abundant NiFe and Ni sulfides. The dominance of metals over silicon results in the formation of crystalline silicates following metal saturation of immiscible Si-rich glasses. High gasification temperatures (1200 - 1500°C) promote the development of equilibrial assemblages. Chemical variations between individual feedstock cokes coupled with nonuniform operational conditions result in three principal categories of petroleum coke slag; 1) sulfide dominant, 2) silica dominant, and 3) oxide dominant. Sulfide dominant slags are not necessarily derived from feedstocks with high sulfur contents, instead they appear to derive from feedstocks rich in chalcophile elements, predominantly Fe and Ni, by attracting sulfur otherwise lost by volatilization. Slagging additives can change the chemical categorization of resulting slags through phase modifications and the formation of new phases; this in tum can strongly alter the physical behavior of the slags. Compositionally diverse spinel oxides are the most common crystalline slag phase because of their wide thermal and compositional stability ranges, refractory nature, and rapid growth kinetics. Spinel compositions are strongly influenced by the inorganic chemistry of the feedstock, the composition of host phases, and the composition of additives. Coke slag spinels are generally enriched in AI, Fe, V, Mg, and Ni, and often contain Cr that is derived from reaction with refractory material. / Ph. D.

The objective of this study was to determine the possible application of ultrasonic inspection for non-destructive, online evaluation of the integrity of heat sealed, flexible package structure commonly used in packaging of aseptic and shelf-stable food products. A scanning acoustic microscope (SAM), Olympus UH-3, and image analysis system were used to establish the operational parameters to ultrasonically inspect the heat seal closure of various flexible packages. The frequency range, attenuation, and focal length (Z-value) were determined respectively for paper laminate containers, plastic and plastic/aluminum pouches and plastic trays with plastic or plastic/aluminum lidding materials. The SAM images of channel leakers, blisters and wrinkles were sufficiently characteristic to allow their identification. The same should be possible in an on-line, ultrasonic testing device through proper design of the transducers and scanning mechanism of the inspection system and by monitoring of the ultrasonic signal. Channel leakers of 20 μm diameter were successfully detected in all package structures with the exception of the paper laminate which scattered the ultrasonic waves. The frequency used for inspection ranged from 30 to 100 MHz and best results were obtained when focussing at the seal bottom surface. As a general rule, lower frequencies were used for inspection of relatively thick seals or laminates containing an aluminum layer. Geometry, thickness, surface characteristics, and laminate composition of the seal to be inspected were found to affect SAM's performance. The SAM was able to detect defects as small as 20 μm when working in the pulse mode, using focussed transducers of frequency ranging between 30 and 100 MHz. However, because smaller defects could not technically be manufactured at the seal interface, this value is not definite and it is believed that smaller defects could be successfully detected, especially in the higher frequency range. For optimum results, seals to be inspected should be free of embossment, flat, and should remain parallel to the surface of the transducer during inspection. Finally, biotests showed that a 20 μm channel leaker in a seal of 5 mm width was of sufficient size to cause post-process contamination in Meal Ready to Eat (MRE, plastics/AI structure) pouches. / Master of Science

The major experimental problems involved in this investigation were two in number. The first problem was that of obtaining an accurate calibration of the electron microscope to be used for making electron micrographs. This was done by comparison with a secondary standard. A Bausch and Lomb Type ILS metalloscope, which was calibrated by use of a steel grating furnished by the manufacturer, was used as the secondary standard. The second problem was the examination of yellow iron oxide pigments manufactured by three major manufacturers for the purpose of comparing individual pigment particles and also determining particle shape and dimensions. Both problems were successfully solved and the following observations were made: 1. The magnification of the RCA Type ENC electron microscope used in the investigation is 4274. 2. The particle size and structure of yellow iron oxide paint pigments made by different manufacturers are the same, i.e., 0.5 micron by 0.1 micron and rod-like in structure. / Master of Science

Si les biologistes connaissent bien les réactions biochimiques des cellules, il n'en est pas de même d'un point de vue mécanique. En effet, un facteur de survie des cellules est leur faculté d'adaptation à leur environnement ainsi que leur réaction face à un stress physique. Les biologistes cherchent donc à connaître les forces en jeu dans ces réactions pour définir un modèle mécanique de la cellule, d'où la nécessité de développer un système de mesure adapté. Ce mémoire propose une description détaillée de mon travail sur la construction d'un microscope à force photonique (PFM). L'idée est de développer un outil non destructif permettant de contrôler et mesurer la force appliquée sur les cellules. Le PFM est une évolution de la pince optique où la particule piégée par le faisceau laser joue le rôle de sonde. Par la détection des variations de son mouvement brownien, nous pouvons mesurer des forces de l'ordre de quelques dizaines de piconewtons. Une telle précision a été possible en portant une attention particulière sur la robustesse du système, la quahté des optiques et de la détection ainsi que sur la précision des réglages.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 1977 / Includes bibliographical references. / Ph. D. / Ph. D. Massachusetts Institute of Technology, Department of Physics

Call number: LD2668 .T4 1979 C66 / Master of Science

No description available.