Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2016-08-04T17:39:56Z No. of bitstreams: 1 joaopaulodasilvasudre.pdf: 2148062 bytes, checksum: c73715b2cb00a515bba21c95536911d3 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-08-05T11:49:24Z (GMT) No. of bitstreams: 1 joaopaulodasilvasudre.pdf: 2148062 bytes, checksum: c73715b2cb00a515bba21c95536911d3 (MD5) / Made available in DSpace on 2016-08-05T11:49:24Z (GMT). No. of bitstreams: 1 joaopaulodasilvasudre.pdf: 2148062 bytes, checksum: c73715b2cb00a515bba21c95536911d3 (MD5) Previous issue date: 2015-05-06 / O objetivo deste estudo foi avaliar o efeito de diferentes tratamentos ácidos, variação da concentração e do tempo de exposição aos ácidos, hidrofluorídrico (HF) e fosfórico (H3PO4), sobre a rugosidade superficial e resistência de união de uma cerâmica vítrea reforçada por dissilicato de lítio cimentada com um cimento resinoso autoadesivo. Cem pastilhas da cerâmica IPS e.max Press® medindo 2 x 7 mm foram divididas em dez grupos de acordo com o tratamento de superfície (n=10): G1, controle, ou seja, sem tratamento; G2, G3 e G4 condicionamento com HF 5% por 20, 40 e 60 segundos, respectivamente; G5, G6 e G7, condicionamento com HF 10% por 20, 40 e 60 segundos, respectivamente; G8, G9 e G10 condicionamento com HF a 10% por 20,40 e 60 segundos respectivamente e, posteriormente, condicionamento com ácido fosfórico 37% por 5 segundos. A análise da rugosidade superficial foi feita em microscópio ótico confocal. As pastilhas representativas de cada grupo foram selecionadas e metalizadas para análise da morfologia superficial em microscopia eletrônica de varredura e em microscópio de força atômica. Para a análise de resistência de união ao microcisalhamento, sobre as superfícies devidamente tratadas, foi aplicado o silano RelyX Ceramic Primer® e aguardou-se 1 minuto para que se realizasse a cimentação. Foram cimentados três cilindros em cada pastilha com o cimento resinoso RelyXTM U200, e fotopolimerizados por 60 segundos cada. Os corpos de prova foram armazenados em água deionizada a 37°C por 24 horas (n=30). Terminado esse tempo, os corpos de prova foram submetidos ao teste de microcisalhamento em uma máquina de ensaios universal Emic DL 2000® com velocidade de 1 mm/minuto até que ocorresse a fratura. Os valores médios de ambos os testes foram submetidos à análise estatística ANOVA dois fatores e as médias comparadas pelo teste de Tukey com 5% de significância. Todas as superfícies fraturadas foram levadas ao estereomicroscópio com aumento de 50 vezes para verificar o padrão de falha ocorrido e alguns corpos de prova após a fratura, foram aleatoriamente escolhidos para representar cada tipo de falha, foram metalizados e levados ao microscópio eletrônico de varredura para caracterização da superfície. A maior rugosidade superficial foi obtida pelo grupo G6 (2,05±0,107) sendo superior estatisticamente aos demais. Já a menor rugosidade foi obtida pelo grupo controle G1 (0,567±0,057) e inferior estatisticamente aos demais. Os grupos G7 (1,785±0,037); G3 (1,608±0,03); G10 (1,551±0,046); G9 (1,449±0,047); G5 (1,443±0,06); G4 (1,422±0,103); G8 (1,339±0,036) e G2 (1,283±0,059) apresentaram valores intermediários de rugosidade. Dentre estes grupos, o G3 (22.75±1.97MPa) foi o que apresentou a maior média de resistência da união com falhas do tipo mista. Por outro lado, o G1 (5.25±1.29MPa) apresentou o menor valor médio de resistência da união com predominância de falhas adesivas. Assim, conclui-se que a concentração do ácido e o tempo influenciaram na rugosidade superficial, sendo maior para o condicionamento com ácido HF a 10%. Para a resistência da união, o tempo de condicionamento e a interação deste com a concentração dos ácidos influenciou de forma significativa; sendo que o ácido HF de menor concentração, 5% por 40 segundos, foi o que apresentou maiores valores. / The objective of this study was to evaluate the effect of different acid treatments, the concentration variation and the time of exposure to hydrofluoric (HF) and phosphoric acids (H3PO4) on the surface roughness and bond strength of a glass-ceramic reinforced by cement lithium disilicate with a self-adhesive resin cement. One hundred tablets of the IPS e.max Press® ceramic measuring 2 x 7 mm were divided into ten groups according to the surface treatment (n = 10): G1, control, or untreated; G2, G3 and G4 etching with 5% hydrofluoric acid for 20, 40 and 60 seconds, respectively; G5, G6 and G7 etching with 10% hydrofluoric acid for 20, 40 and 60 seconds, respectively; G8, G9 and G10 etching with 10% hydrofluoric acid for 20, 40 and 60 seconds respectively, and subsequently etched with phosphoric acid at 37% for 5 seconds. Analysis of surface roughness was performed confocal optical microscope. Representative tablets of each group were selected and metallized for analysis of surface morphology in scanning electron microscopy and atomic force microscope. For the analysis of bond strength to microshear, on properly treated surfaces, the silane RelyX Ceramic Primer® was applied and waited up to 1 minute to the holding of the cementing. Three-cylinder in each tablet were cemented with resin cement RelyXTM U200, and light cured for 60 seconds. The specimens were stored in deionized water at 37C for 24 hours (n = 30). After this time, the specimens were submitted to microshear test in a universal testing machine Emic DL 2000® with speed of 1 mm/min until the fracture. The average values of both tests were submitted to ANOVA two factors and the means compared by Tukey test at 5% significance level. All fractured surfaces were taken to the stereomicroscope with 50X enlargement to verify the pattern of failure occurred and some specimens with significant fractures of each type of failure were metallized and taken to the scanning electron microscope for surface characterization. The increased surface roughness was obtained by the G6 group (2.05 ± 0.107 N) and statistically superior. Already the slightest roughness was obtained by G1 control group (0.567 ± 0.057) and statistically lower to others. The G7 (1.785 ± 0.037); G3 (1.608 ± 0.03); G10 (1.551 ± 0.046); G9 (1.449 ± 0.047); G5 (1.443 ± 0.06); G4 (1.422 ± 0.103); G8 (1.339 ± 0.036) and G2 (1.283 ± 0.059) showed intermediate roughness values. Among these groups, the G3 (22.75 ± 1.97 N) was presented the highest mean bond strength with failures of mixed type. Moreover, G1 (5.25 ± 1.29 N) had the lowest average value of the bond strength with a predominance of adhesive failures. Thus, it is concluded that the acid concentration and time influence the surface roughness, being greater for etching with 10% hydrofluoric acid. For the bond strength, the conditioning time and the interaction of this with the concentration of the acid had a significant influence; being that the hydrofluoric acid of lower concentration, 5% for 40 seconds, showed the highest values.

Les façades des nouveaux bâtiments et des bâtiments existants sont altérées par la pénétration de l'eau. Afin de protéger les bâtiments et surfaces exposées aux intempéries, des traitements contenant des agents hydrophobes doivent être appliqués.<p>Les traitements utilisés à l’heure actuelle sont des traitements de surface qui se dégradent au cours du temps. L'agent hydrophobe, présent en surface, est soumis à des conditions très rudes telles que des rayonnements ultraviolets, de grandes variations de température, de l'abrasion .qui réduisent l’efficacité et la durabilité des traitements. La plupart des traitements aujourd'hui disponibles, fournisse une barrière efficace au passage de l’eau à court terme, mais doivent donc être réappliqués régulièrement. <p>Le projet de recherche, présenté ici, traite de la mise en place d'un traitement de masse de matériaux cimentaires utilisés dans la protection de structures (joints, crépi .). Ce traitement devrait offrir une protection à long terme, mais ne devrait pas modifier de manière significative les propriétés mécaniques des matériaux. <p>Les avantages d'un traitement de masse sont évidents. Seule une petite partie de l'agent hydrophobe est exposée et dégradée par les conditions climatiques et l'abrasion de surface ne porte pas atteinte à l'intégrité du traitement.<p>Une étude fondamentale a été menée afin d'étudier l'influence de l'incorporation d´agents à base de silicium sur les processus d'hydratation des ciments Portland et de comprendre leur mode d'action. Deux agents (alpha,omega dihydroxypolydimethylsiloxane et n-octyltriethoxysilane) et deux ciments Portland (ordinaire et blanc CEM I 42,5N) ont été choisis et étudiés. Trois modes d´introduction (liquides purs, émulsions et granules) ont été mis en œuvre et comparés. <p>Le but est de déterminer les meilleures conditions pour obtenir un traitement efficace et durable tout en préservant les propriétés mécaniques. Les résultats d'absorption d'eau par capillarité et de perméabilité à la vapeur d’eau sont prometteurs et les essais mécaniques sur mortiers n’ont pas montré de diminutions significatives des résistances mécaniques. <p><p>La microstructure et la progression de l'hydratation des matrices cimentaires adjuvantées et de référence, ont été caractérisées par calorimétrie à conduction, par calorimétrie différentielle à balayage couplée à la thermogravimétrie, par spectroscopie infra-rouge, par diffraction des rayons X, par porosimétrie au mercure, et par microscopie électronique à balayage.<p><p>La durabilité des matériaux adjuvantés a été étudiée afin de montrer la pertinence des traitements ainsi que l'évaluation de la progression de l'hydratation. Les performances hydrofuges ainsi que l’évolution de la microstructure, à l’issue des différents vieillissements artificiels et naturels, ont été déterminées.<p>Les mortiers mis en œuvre ont été soumis à des vieillissements artificiels simulant des conditions proches de celles rencontrées en pratique (tels que des cycles rayonnements UV, pluie, sel, gel/dégel…). Une amélioration de la durabilité des mortiers adjuvantés a été observée. Les résultats sont très encourageants et confirment l'intérêt d’un tel traitement dans la masse.<p><p>/Protection of cement-based materials means above all, moisture protection because water is primarily responsible for inducing damaging physical and chemical processes in building materials. In most cases, water repellents are applied either directly during the construction or insulation process; or as a post-treatment of the exposed surfaces in order to protect the buildings from further decay. A new way is to develop a bulk treatment for cement-based materials which should provide a long term protection without modifying the mechanical properties of the cementitious materials. <p>The advantages of a bulk treatment are obvious i.e. only a small part of the hydrophobic agent is exposed and degraded by the UV. In addition, surface abrasion does not affect the integrity of the treatment. <p><p>A fundamental study was initiated to investigate the influence of the incorporation of two active silicon-based agents (already used as post-building treatments) on the hydration processes of Portland cements and to understand the involved mechanisms of interaction. <p>Two agents (alpha,omega dihydroxypolydimethylsiloxane and n-octyltriethoxysilane) and two Portland cements (Ordinary and White Portland Cement CEM I 42,5N) were chosen and studied. Three incorporation modes (pure liquids, water emulsions and granules) were investigated. The effects of the three modes were compared.<p>The aim was to determine the best conditions for an efficient and sustainable treatment preserving the mechanical properties of the materials. <p>The results of capillary water penetration and water vapor permeability are promising and are not accompanied by a significant decrease of the mechanical performances<p><p>The microstructure and progression of hydration of admixtured cement pastes were characterized by conduction calorimetry, differential scanning calorimetry, thermo-gravimetry, infra-red spectroscopy, X-ray diffraction, mercury intrusion porosimetry, and scanning electron microscopy. <p>In addition, the durability of water-repellent additives and of the admixtured cement was studied in order to show the relevance of the treatments as well as the assessment of the progression of hydration and the type of products that were developed. <p>Mortar specimens were submitted to artificial ageing cycles such as freeze-thaw cycles, ultraviolet cycles and rain-sun cycles. <p>The general trend is an improvement of the durability of admixtured mortars. <p>The results are very encouraging and confirm the interest of the bulk mortar treatment. <p><p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

The main goal of this thesis is to deposit metal particles on the surface of 2D nanoplatelets using a controlled cementation process. As a proof of concept, copper (Cu) and Graphene Nanoplatelets (GNP) were chosen as the representative metal and 2D nanoplatelets, respectively. Specific goals of this study include depositing nanometer scale Cu particles on the surface of GNP at a low concentration (approximately 5 vol.%) while maintaining clustering and impurities at a minimum. Parametric studies were done to attain these goals by investigating various metallic reducer types and morphologies, GNP surface activation process, acid volume % and copper (II) sulfate concentrations. Optimal conditions were obtained with Mg ribbon as a reducer, 3 minutes of activation, 1 vol.% of acetic acid and 0.01 M CuSO4. The GNP-Cu powder synthesized in this work is a precursor material to be consolidated via spark plasma sintering (SPS) to make a nacre-like, layered structure for future studies.

Orientador: Luis Roberto Marcondes Martins / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-07T21:42:27Z (GMT). No. of bitstreams: 1 PedrosaFilho_CelsodeFreitas_D.pdf: 1514708 bytes, checksum: 68479f75bac6f0d3bdbb5ec943719f31 (MD5) Previous issue date: 2006 / Resumo: Neste estudo avaliou-se a resistência ao cisalhamento por extrusão de pinos de fibra de vidro, reembasados ou não com compósito, cimentados com cimento resinoso em dentina intra-radicular, avaliando os segmentos cervical, médio e apical. Selecionaram-se 20 incisivos bovinos com dimensões semelhantes, removendo a porção coronária, padronizando o comprimento das raízes em 16 mm. Após, incluiu-se as raízes em resina acrílica, realizando tratamento endodôntico e, então o preparo dos espaços para os pinos, dividindoas, em seguida, aleatoriamente em dois grupos com dez amostras cada. Os elementos do grupo 1 receberam pinos de fibra de vidro somente cimentados, e do grupo 2 pinos de fibra de vidro reembasados com compósito e posteriormente cimentados. Ao término dos procedimentos de cimentação, realizou-se a secção dos segmentos radiculares, submetendo, então, os corpos-de-prova ao teste push-out em máquina de ensaios universal, através de ponta ativa cilíndrica com 1 mm de diâmetro, à velocidade de 0,5 mm/min, até extrusão do retentor. Obteve-se os seguintes valores médios de resistência de união, em MPa: grupo 1, terços cervical = 6,24 ± 2,68(b), médio = 4,27 ± 2,00(b) e apical = 4,46 ± 2,82(b); grupo 2, terços cervical = 11,83 ± 1,69(a), médio = 11,81 ± 3,86(a) e apical = 10,39 ± 2,44(a). Submeteram-se os valores à análise de variância e ao teste de Tukey com nível de significância de 5%, indicadas acima através de letras diferentes. Os pinos de fibra de vidro reembasados com compósito apresentaram valores estatisticamente superiores de união em todos os segmentos radiculares quando comparados com pinos somente cimentados. Observou-se também a ausência de diferença significativa entre os terços radiculares avaliados para cada grupo distintamente. Os resultados demonstraram que a técnica de reembasamento mostrou-se efetiva em melhorar a retenção do pino de fibra de vidro estudado / Abstract: This study evaluated the bond strength of fiber posts, relined or not with composite resin, luted with resinous cement to radicular dentin, evaluating cervical, median and apical root segments. Twenty bovine incisors, with similar dimensions, were selected and cut 16 mm from the apical limit. The roots were embedded in acrylic resin and the radicular canals were root treated and post space prepared with a depth of 9 mm. Samples were randomly assigned to two groups of ten roots each. Group 1 received glass fiber posts (Fibrekor) luted with dual-cure resin cement (RelyX ARC) in association with a bonding system (Adper Single Bond). In Group 2 the same type of posts were relined with composite (P-60) for further cementation with the same materials used in Group 1. After cementation procedures roots were sectioned transversally and three sections, from cervical, medium and apical thirds were obtained. Push-out test was performed in a universal testing machine with a 1 mm diameter steel rod at cross-head speed of 0,5 mm/min until post extrusion. Collected data was statistically analyzed by twoway ANOVA and Tukey HSD test (p<0,05). The measured retention strengths for cervical, medium and apical thirds were: Group 1, 6.24 ± 2.68(b), 4.27 ± 2.00(b) and 4.46 ± 2.82(b) ; Group 2, 11.83 ± 1.69(a), 11.81 ± 3.86(a) and 10.39 ± 2.44(a). Glass fiber composite relined posts presented statistically higher retention values in cervical, medium and apical thirds when compared to non-relined posts. Within each group, no differences were found among radicular thirds. The results indicate that the tested technique showed effective improvement of glass fiber post retention strength / Doutorado / Dentística / Doutor em Clínica Odontológica

No description available.

Sur les bordures du Bassin parisien et leurs périphéries, plus particulièrement sur lessubstrats jurassiques et crétacés, on trouve des paléokarsts fossilisés par des dépôtsferrugineux.Plus de 60 sites aériens ou souterrains ont été étudiés au Sud de l'Ardenne, de laThiérache ardennaise au Pays-Haut ; sur le contact Jurassique-Crétacé aux confins de laLorraine et de la Champagne (Vallage, Barrois et Haut-Pays) ; au Nord du Massif Central,de la Champagne berrichonne au Montmorillonnais ; sur les plateaux crayeux deNormandie, du Pays d'Ouche et de la Plaine de Saint-André ; à la charnière entre Riftsbressan et rhénan (fossé de la petite Saône, plateaux de Vesoul, Collines préjurassiennes).Les analyses de près de 250 échantillons (macroscopie et microscopie, granulométrie etmorphoscopie, analyses chimiques et minéralogiques), ont montré que ces ferricrètesprésentent des faciès extrêmement variés tant sur le plan de la structure que sur ceux dela forme ou de la taille. Ces faciès peuvent résulter, soit d'un remaniement mécaniquedominant, soit d'un remaniement chimique dominant voire exclusif, ou encore alliant desremaniements à la fois mécaniques et chimiques.Les dépôts ferrugineux issus à l'origine de ferricrètes générées lors de grandes périodesd'altération ferralitiques qui ont affecté l'Europe occidentale entre le Crétacé inférieur et ledébut du Tertiaire ont évolué au gré de l'encaissement des vallées au Plio-Quaternaire.Par conséquent le karst est générateur de faciès spécifiques et contribue à amplifier lesprocessus de remaniement chimique ou mécanique. / That's on the board of the Parisian Basin and its surrounding, and more particularly on theJurassic as well as the cretaceous subterrane, we can find some paleokarsts fossilized.More of 60 underground or aerial sites have been studied in the South of the Ardenne,from the Thiérache ardennaise to the Pays-Haut ; on the contact of the Jurassic-Cretaceous to the limits of the Lorraine and the Champagne (Vallage, Barrois and Haut-Pays) ; to the North of the Massif Central, from the Champagne berrichonne to theMontmorillonnais ; on the chalky trays of Normandy (Pays d?Ouche, Plaine de Saint-André) ; at the hinge between bressan and rhenan Graben (fossé de la petite Saône,Plateaux de Vesoul, Collines pré-jurassiennes).Analyses made on 250 samples (macroscopic and microscopic analysis, granulometryand morphoscopy, mineralogical and chemical analyses), have shown that these ironcementation present facies extremely varied on both structure and size. These facies canresult, either in a dominant mechanical revision, or in a chemical revision dominatingperhaps exclusive, or in allying both chemical or mechanical reworking.The stemming ferruginous deposits coming from the ferricrusts generated during theperiods of ferralitic alteration having affected the Western Europe between the inferiorCretaceous and the beginning of the Tertiary, have evolved according to the collection ofvalleys during the Plio-Quaternary. Consequently the karst is generator of specific faciesand contributes to amplify chemical or mechanical revision processes.

Several factors must be considered in the selection of angled abutments. In these situations, the clinician should find a practical way to overcome the lack of retention. The purpose of this study was to evaluate the bond strength of metallic crowns cemented to straight and angled customizable abutments with different definitive luting agents. Ninety one regular external hex analogs and abutments were divided in Control group (C): customizable straight abutment cemented with zinc phosphate (n = 10); three groups (n = 10) with 17° angled abutment cemented with zinc phosphate (A17ZP), Panavia F (A17RM) and RelyX U100 (A17R) cements and more three groups (n = 10) with 30° angled abutment also cemented with zinc phosphate (A30ZP), Panavia F (A30RM) and RelyX U100 (A30R) cements. The metal copings were cemented onto their corresponding metal dies and crowns cemented with Panavia F were pre-treated with an alloy primer containing an acid-phosphated monomer (MDP). Data from the all groups were compared to control group with a 1-way ANOVA (&#945;=.05) and Dunnet s test, and comparison between tested groups were done with 2-way ANOVA (&#945;=.05) and Tukey s test. SEM and CLSM evaluation were performed (n = 3) aiming to investigate microscopic features of the abutment-cement-crown interfaces. The mean force (SD) required to dislodge the crowns in the C, A17ZP, A17RM, A17R, A30ZP, A30RM and A30R groups was 357,26 (62,21) N; 251,50 (20,13) N; 397,05 (88,48) N; 328,71 (79,87) N; 276,70 (17,96) N; 377,81 (90,61) N and 335,42 (88,34) N respectively. Panavia F presented the higher tensile bond strength results and zinc phosphate the lower between the tested groups. Only A17ZP group was different from control group (p=.007) and the abutment taper has no influence in retentive values. Zinc phosphate showed an inhomogeneous cement line in SEM and CLSM analysis. The presence of MDP primer could be perceived in CLSM images of Panavia F group. Within the limitations of this in vitro study, the Panavia F presented the higher bonding strength between tested groups, however, all 3 cements tested were similar to control group except A17ZP group, showing that in the conditions of the study they all can be successfully used. / Vários fatores devem ser considerados na seleção dos pilares angulados, assim, muitas vezes, o clínico deve encontrar uma forma prática de superar a falta de retenção resultante das características desse tipo de pilar. O objetivo deste estudo foi avaliar a resistência de união de coroas metálicas cimentadas sobre pilares personalizáveis retos e angulados, cimentados com diferentes agentes de cimentação definitivos. Noventa e um análogos de implantes regulares do tipo hexágono externo foram divididos em Grupo controle (C): pilar reto personalizável cimentado com fosfato de zinco (n = 10); três grupos (n = 10) com pilares angulados de 17° cimentados com fosfato de zinco (A17F), Panavia F (A17RM) e RelyX U100(A17R) e ainda mais três grupos (n = 10) com pilares angulados de 30° também cimentados com cimento de fosfato de zinco (A30F), Panavia F (A30RM) e RelyX U100 (A30R). Coroas de Níquel-Cromo foram confeccionadas e cimentadas em seus pilares correspondentes sendo que as coroas cimentadas com Panavia F foram pré-tratadas com um primer para metal contendo monômero ácido fosfatado (MDP). Dados de todos os grupos foram comparados ao grupo controle por meio da análise de variância ANOVA - One way (&#945; =0,05) e teste de Dunnet, e a comparação entre os grupos testados foi realizada por meio de análise de variância ANOVA Two way (&#945; =0,05) e teste de Tukey. Ainda as avaliações em MEV e MVCL foram realizadas com 3 amostras representativas de cada grupo com o objetivo de investigar as características microscópicas das interfaces pilar-coroa-cimento. A média de força (DP) necessária para deslocar as coroas nos grupos C, A17F, A17RM, A17R, A30F, A30RM e grupos A30R foram, respectivamente, 357,26 (62,21) N; 251,50 (20,13) N; 397, 05 (88,48) N; 328,71 (79,87) N; 276,70 (17,96) N; 377,81 (90,61) N e 335,42 (88,34) N. O cimento Panavia F apresentou os resultados mais elevados de resistência a tração (RT) e o fosfato de zinco apresentou os menores valores de RT entre os grupos testados. Apenas o grupo A17F foi estatisticamente diferente do grupo controle (p = 0,007) e a inclinação das paredes axiais do pilar não influenciou os valores de retenção obtidos. O fosfato de zinco apresentou uma linha de cimentação não homogênea na análise em MEV e MVCL. A presença de primer contendo MDP pode ser percebida nas imagens de MVCL do grupo Panavia F. Dentro das limitações deste estudo in vitro, o Panavia F apresentou a maior resistência de união entre os grupos testados, no entanto, todos os três cimentos testados foram semelhantes ao grupo controle, exceto o grupo A17F grupo, mostrando que nas condições do estudo todos eles podem ser usados com sucesso. / Mestre em Odontologia

Les zones de failles concentrent la migration de fluides et la déformation dans la croûte supérieure. Les propriétés hydrauliques des formations argileuses en font des excellents sites de stockage et des roches mères performants. Les zones de failles peuvent jouer deux rôles contraires dans la circulation de fluides, soit elles s’expriment sous forme de drains, soit elles constituent une barrière, et souvent les deux rôles sont combinés au sein d’une même zone de failles. Les processus de migration des fluides dans les zones de failles affectant les argiles sont peu connus. Cette étude s’est focalisée sur la structure, les paléo-circulations, les circulations actuelles lors de tests d’injection et les propriétés pétro-physiques de la zone de failles présente dans le laboratoire de recherche souterrain de Tournemire dans les argilites Toarciennes. La structure de la zone de failles a été caractérisée par des forages et reconstituée en 3D par modélisation numérique, permettant de définir des faciès de déformation. L’architecture de la zone de failles se caractérise par une imbrication de facies de déformations plus ou moins intenses sans claire organisation en cœur et zone endommagée comme observée dans les roches plus dures. Les zones intactes, fracturées et les brèches sont respectivement caractérisées par des porosités matricielles comprises entre 9.5-13.5, 10-15 et 13-21%. La circulation de fluide se concentrant aux limites de la brèche et au niveau des zones de failles «immatures» ou secondaires comprises dans les zones fracturées. Lors de son activité, la zone de failles a déjà été affectée par au moins deux phases de circulations de fluides. / Fault zones concentrate fluids migration and deformations in the upper crust. The shale hydraulic properties make them excellent storage sites and hydrocarbon reservoirs/source rocks. Fault zones can play two roles in the fluid circulation; drains or barriers, in general, both roles are combined within the same fault zone. What are the conditions that promote the fluid circulation along the fault zones in shales and what are the fault zone impacts on the formation properties are relatively poorly explored key questions. This study focused on characterizing the relationships between fault architecture, paleo-fluid as well as current fluid circulations through the analysis of fault calcite mineralization, injection tests and petrophysical properties conducted on a fault zone outcropping underground in the Tournemire research laboratory nested in the Toarcian shale. The fault zone structure was characterized using boreholes data and reconstructed in 3D through modeling to define different deformation facies. No clear facies organization is observed, a fault core and a fault damage zone being difficult to define as it is in hard rocks. The intact, fractured and breccia facies are characterized by a porosity of 9.5-13.5, 10-15 and 13-21%. Large fluid flowrate concentrated along a few “channels” located at the breccia boundaries and in the secondary fault zones that displayed fractured facies and limited breccia fillings. Detailed microstructural and geochemical analysis at the breccia/fractured zones interface revealed that fluids circulated out of the main shear zones, in micro-more or less inherited fractures highlighting a decoupling between fault slip and fluid migrations.

Made available in DSpace on 2014-08-20T14:30:09Z (GMT). No. of bitstreams: 1 Dissertacao_rafael_sarkis_onofre.pdf: 1491340 bytes, checksum: 00453dc2916d638be0bec47f9d29aa11 (MD5) Previous issue date: 2012-12-13 / The best way to restore endodontically treated teeth has been discussed in the literature because some factors can influence the post selection and the final restoration. Two of the most used intra-radicular posts are cast metal posts and glass fiber posts. Moreover, there is a large variability of in vitro studies that evaluate the use of different resin cement and the alterations of technique and the influence in the bond strength of glass fiber posts. The aims of the study were to compare the survival of two types of dental posts used to restore endodontically treated teeth with great damage of coronal walls and verify through a systematic review if there is difference on bond strength of glass fiber posts to dentin between self-adhesive and regular resin cements. Systematic review: In vitro studies that investigated the bond strength of glass fiber post luted with self-adhesive (RC) and regular (RC) were selected. Global comparison between self-adhesive (RC) and regular resin cement was performed. Two subgroup analyses were performed: self-adhesive resin cement x regular resin cement (etch-and-rinse adhesive), self-adhesive resin cement x regular resin cement (self-etch adhesive). The three analyses performed showed favorable results to self-adhesive resin cement. Clinical trial: The teeth were randomly allocated into two groups depending on the post used: glass fiber or cast metal post. Fifty-four (45 women) patients and 72 teeth were evaluated up to 3 years and the survival probabilities were 97.1% and 91.9% to cast metal posts and glass fiber posts. Four failures were observed, 2 glass fiber posts debonding (premolar and anterior tooth), 1 glass fiber post debonding associate with root fracture and 1 root fracture with a cast metal post. We can conclude that in vitro literature seems to suggest that the use of self-adhesive cement could help to achieve higher bond strength of GFPs to the root canal and after 3 years of follow up, both posts presented the same clinical performance and / A melhor maneira de se restaurar dentes tratados endodonticamente vem sendo muito discutida na literatura principalmente porque alguns fatores como a escolha do pino a ser utilizado pode influenciar o resultado final da restauração. Dois dos retentores intra-radiculares mais utilizados atualmente são os núcleos metálicos fundidos e os pinos de fibra de vidro. Além disso, existe uma grande variabilidade de estudos in vitro que avaliam tanto a utilização de diferentes cimentos resinosos como alterações das técnicas e a influência na resistência de união de pinos de fibra de vidro. O objetivo deste trabalho foi avaliar as taxas de sucesso clínico de dentes tratados endodonticamente sem remanescente coronário e restaurados com de pino de fibra de vidro ou núcleo metálico fundido através de um ensaio clínico randomizado. Além disso, realizar uma revisão sistemática da literatura de ensaios in vitro que comparassem a resistência de união de pinos de fibra de vidro cimentados com cimento resinoso regular e cimento resinoso autoadesivo. Para a revisão sistemática, estudos in vitro que avaliaram a resistência de união de pinos de fibra de vidro cimentados com cimento autoadesivo e cimento regular foram selecionados. As seguintes metánalises foram realizadas: comparação global entre cimento autoadesivo x cimento regular e análises de subgrupo cimento autoadesivo x cimento regular (adesivo etch-and-rinse) e cimento autoadesivo x cimento regular (adesivo self-etch). As três análises mostraram resultados estatisticamente significantes e favorecendo o uso de cimento autoadesivo. No ensaio clínico, os dentes selecionados foram randomizados e alocados em 2 grupos dependendo do pino utilizado. Após 3 anos, 54 pacientes (72 dentes: 35 núcleos metálicos fundidos e 37 pinos de fibra de vidro) foram avaliados. As taxas de sobrevivência foram 97,1% e 91,9% para núcleos metálicos fundidos e pinos de fibra de vidro respectivamente. Quatro falhas foram observadas: duas descimentações de pinos de fibra de vidro (pré-molar e dente anterior), uma descimentação de pino de fibra de vidro associada a fratura radicular (pré-molar) e uma fratura radicular associada ao uso de núcleo metálico fundido (molar). Conclui-se que a literatura sugere que o uso de cimento resinoso autoadesivo poderia ajudar a conseguir maior resistência de pinos de fibra vidro ao canal radicular e que após 3 anos, ambos os pinos apresentaram performance semelhante

Marine clay deposits are characterized by very soft to soft consistencies (undrained strength 1-50 kPa), presence of saline pore solution and low-swelling clays. Besides, loss of metastable structure on disturbance, poor undrained strengths of soft clays is contributed by high water contents. Presence of saline pore solution and low-swelling clays (illite, chlorite, kaolinite) play an important role in developing metastable structure of soil sediments deposited in marine environment. The pore solution salinity regulates the “physico-chemical (A - R) stress” that in turn has significant bearing on development of the metastable structure. Metastable structure refers to edge-face, edge-edge associations in card-house arrangement of platy/elongate particles that develop during deposition. Loss of metastable structure of soft marine clays upon disturbance leads to excessive settlements and slope failures. Besides A - R forces, metastable structure of marine clays is contributed by cementation bonds, thixotropic hardening, ion leaching, formation or addition of dispersing agents and chemical weathering. Secondary compression also causes bonding of micro-structural units that increase stiffness and strength of the metastable structure. Review of literature brings out that majority of studies examining the role of physico-chemical factors on the engineering behavior of marine clays have focused on illite rich sediments. However, non-swelling clay, namely, kaolinite is also encountered in marine deposits (example, Pusan clay, Singapore clay, Sarapui soft clays). Kaolinites differ from illites in being 1:1 mineral (unit layer comprises of 1 silica sheet bonded to 1 gibbsite sheet) and having strong hydrogen bonding between unit layers. Consequently, kaolinite particles are thick (0.3 to 3 ìm thickness) with low surface area (10 to 20 m2/g). Also the hydrogen bonding between unit layers do not allow them to separate on hydration. Combination of very low isomorphous substitution (Al for Si 1 in 400), low cation exchange capacity (3 meq/100g), and low surface area, lead to negligible development of diffuse double layer repulsion forces between kaolinite particles. Strong positive edge (developed on broken bonds at particle edges from adsorption of hydrogen ions) negative face attraction between kaolinite particles, encourages flocculation of particles at range of water contents. It was therefore considered of interest to examine the engineering response of kaolinites to changes in pore solution salinity from leaching effects. The focus of the thesis is hence to gain better understanding of physico-chemical (pore solution salinity, A - R forces) and mechanical (secondary compression, loss of overburden) factors towards development of metastable structure of kaolinite clays deposited in synthetic seawater environments in the context of their compressibility and undrained strength characteristics. Laboratory experiments are performed with kaolinites that are slurry consolidated in conventional consolidometers in saline and synthetic seawater solutions. The metastable structure developed by consolidated specimens is relevant to alluvial marine sediments that contain kaolinite (example, Pusan clay, Singapore clay, Sarapui soft clays). The structure of the thesis is as follows: Chapter 1 gives an introduction to the thesis. Chapter 2 provides a detailed review of literature on the role of chemical factors (pore solution composition, A - R forces, osmotic suction) and mechanical processes (secondary compression and overconsolidation) in developing metastable structure of kaolinite specimens subjected to slurry consolidation and the consequent influence of metastable structure on compression, undrained strength and sensitivity characteristics of clay specimens. The Chapter also defines the scope and objectives of the study. Chapter 3 details the experimental program undertaken to bring out the role of chemical factors and mechanical processes in influencing the 1-dimensional compression and undrained strength characteristics of slurry consolidated kaolinites prepared in saline medium. Chapter 4 delineates the role of chloride salt solutions (sodium, magnesium and calcium) and synthetic seawater solution in contributing to the metastable structure developed by slurry consolidated kaolinites at various vertical effective stress (óv’) and the consequent influence of metastable structure on 1-dimensional compression, undrained strength and sensitivity characteristics of the clay. Chapter 5 examines influence of secondary compression on metastable structure developed by kaolinites that were slurry consolidated in 24.53 g/L sodium chloride and synthetic seawater solutions and the consequence of the developed metastable structure on undrained strength and sensitivity. The chapter also examines the consequences of secondary compression experienced by soft overconsolidated kaolinites on their undrained strength and sensitivity characteristics. Chapter 6 examines the relative influence of differential osmotic stress and electrochemical stress on the consolidation behaviour of kaolinite specimens that are slurry consolidated in sodium chloride solutions. The osmotic efficiencies (á) of kaolinite were obtained using the Fritz-Marine Membrane Model. Chapter 7 summarizes the major conclusions of the thesis.