Made available in DSpace on 2014-06-11T19:31:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-11-06Bitstream added on 2014-06-13T19:41:14Z : No. of bitstreams: 1 ueda_jk_dr_arafo.pdf: 3962196 bytes, checksum: a5332fed2f0a6d42be6d3100aaa4ce11 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A preservação e a restauração de dentes despolpados severamente debilitados é um procedimento complexo e relativamente imprevisível. Este estudo avaliou a resistência à fratura de raízes bovinas experimentalmente debilitadas, reconstruídas internamente com diferentes materiais restauradores em combinação com pinos pré-fabricados de fibra de vidro comparados com raízes íntegras restauradas com núcleo metálico fundido ou pino de fibra de vidro. Foram selecionadas raízes de 120 (n=15) incisivos bovinos inferiores de dimensões semelhantes, dos quais, 90 foram internamente preparados para simular uma raiz debilitada. Todas as raízes foram preenchidas com diferentes materiais restauradores e os espécimes foram submetidos ao teste de resistência ao fracasso/ fratura com a aplicação de uma carga compressiva tangencial a um ângulo de 135º em relação ao longo eixo axial das raízes. Resultados indicaram diferenças estatisticamente significante entre os grupos. As raízes debilitadas restauradas com núcleo metálico fundido (grupo NMF-RD) demonstraram os mais baixos valores de resistência à fratura (107.7436 N), sendo estatisticamente diferentes dos demais grupos. As raízes íntegras restauradas com núcleo metálico fundido (NMF-RI) mostraram os maiores valores de resistência (362.3308 N), mas com diferenças estatisticamente significantes somente quando comparadas às raízes debilitadas restauradas com cimento resinoso dual (Variolink II, Ivoclar Vivadent - grupo Vario-RD), cimento resinoso autopolimerizável (Multilink, Ivoclar Vivadent - grupo Multi-RD) e cimento de ionômero de vidro modificado por resina (Vitremer, 3M ESPE - grupo Vitre-RD) associado com pino de fibra de vidro... / The preservation and restoration of severely weakened pulpless teeth is a difficult and relatively unpredictable procedure. This study evaluated the resistance to fracture of experimentally weakened bovine roots internally reconstructed with different filling materials in combination with prefabricated fiberglass posts compared with restored roots that were relatively intact. The roots of 120 mandibular bovine incisors with similar bulks were selected. Of these, 90 were internally prepared to standardized dimensions, thereby simulating weakness. All roots were filled with different restorative materials. The specimens were submitted to the fracture resistance testing with the application of a tangential compressive loading at an angle of 135º in relation to the long axes of the roots. Results indicated statistically significant differences among the groups. The weakened roots restored with the cast post-core (group NMF-RD) demonstrated the lowest fracture resistance values (107.7436 N), which were significantly different from the averages of the remaining groups. The healthy roots restored with the cast post-core (group NMF-RI) showed the highest values (362.3308 N), but statistically significant differences were observed only when compared with weakened roots restored by the dual-cured resin cements (Variolink II, Ivoclar Vivadent - group Vario-RD), chemically cured resin cements (Multilink, Ivoclar Vivadent - group Multi-RD) and resin-modified glass-ionomer cement (Vitremer, 3M ESPE - group Vitre-RD) associated with fiberglass posts. There was not statistically significant differences among the groups of the weakened roots restored with self-adhesive universal resin cement (RelyX Unicem, 3M ESPE - group Unicem-RD), composite resin (Tetric 15 Ceram, Ivoclar Vivadent - group Tetric-RD), group Vitre-RD and group Vario-RD... (Complete abstract click electronic access below)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In addition to chemical mechanical preparation, pulp therapy for primary teeth requires a root canal filling that is able to maintain the antimicrobial activity to sanitize the root canal. Since the materials are in close contact with the dental tissues, it is essential to perform biocompatibility testing to certify the safety of these products for clinical application. The aim of this study was to evaluate the cytotoxicity, oxidative stress, and genotoxicity in vitro of four iodoform pastes, three calcium hydroxide pastes, and their main components. Peripheral blood mononuclear cells and DNA from calf thymus were exposed to extracts of these products. Cytotoxicity was assessed with an MTT assay. The generation of reactive oxygen species (ROS) was evaluated by a DCFH-DA assay, and lipid peroxidation was evaluated by a TBARS assay. The genotoxicity was evaluated using alkaline comet assay and GEMO assay. All tests were performed at 24 and 72 h, except for GEMO. After Kolmogorov Smirnov test, the results were analyzed by Kruskal Wallis and Dunn s test, ANOVA, and Dunnett s test (p<0.05). In the MTT assay, the chlorhexidine, Maxitrol®, neomycin sulfate + bacitracin pastes, and their components (chlorhexidine, propylene glycol, and camphorated parachlorophenol) decreased cell viability after 24 h. After 72 h, no change was observed in cell viability and lipid peroxidation for any of the groups. Lipid peroxidation was observed with exposure to calcium hydroxide pastes, calcium hydroxide, and iodoform after 24 h. Exposure to chlorhexidine, Guedes-Pinto, calcium hydroxide pastes, chlorhexidine, neomycin sulfate + bacitracin, camphorated parachlorophenol, iodoform, and calcium hydroxide resulted in an increase in ROS after 24 h, whereas propylene glycol, iodoform pastes, and their components (except for iodoform alone), increased the ROS after 72 h. In the comet assay, damaged DNA was not present with exposure to iodoform pastes for both times. However, in the GEMO assay, the chlorhexidine paste showed genotoxic effects. Calcium hydroxide paste and calcium hydroxide caused DNA damage in both tests. Thus, the pastes and components varied in their ability to induce cytotoxicity, genotoxicity, and oxidative stress. In general, the Guedes-Pinto, Maxitrol®, and neomycin sulfate + bacitracin pastes exhibited better biocompatibility in vitro. / A terapia pulpar em dentes decíduos requer como complemento ao preparo químico-mecânico, pastas obturadoras capazes de manter o poder antimicrobiano, ajudando na sanificação do canal radicular. Por estabelecerem íntimo contato com os tecidos dentários, é imprescindível a realização de testes de biocompatibilidade que atestem a segurança desses produtos para aplicação clínica. O objetivo desse estudo foi avaliar a capacidade de quatro pastas iodoformadas, três pastas de hidróxido de cálcio, e seus principais componentes, em causar citotoxicidade, estresse oxidativo e genotoxicidade in vitro. Células mononucleares de sangue periférico e DNA purificado de timo de bezerro (teste GEMO) foram expostos a extratos desses produtos. O ensaio MTT avaliou a citotoxicidade. A geração de espécies reativas de oxigênio foi avaliada pelo teste DCFH-DA, e a peroxidação lipídica pelo ensaio TBARS. A genotoxicidade foi avaliada pelo Ensaio Cometa Alcalino e GEMO. Todos os testes foram realizados em 24 e 72 horas, exceto o GEMO. Após teste de normalidade Kolmogorov-Smirnov, os resultados foram analisados por Kruskal-Wallis e Dunn, ANOVA e Dunnet, com p<0,05. No MTT, as pastas Clorexidina, Maxitrol®, Sulfato de Neomicina+Bacitracina, os componentes clorexidina, PMCC e o propilenoglicol diminuiram a viabilidade celular em 24h. Em 72h, nenhum produto provocou diminuição da viabilidade celular e lipoperoxidação. A lipoperoxidação foi causada por pastas de hidróxido de cálcio, o hidróxido de cálcio e o iodofórmio em 24h. O aumento das ERO foi provocado pelas pastas Clorexidina, Guedes-Pinto, e pastas de hidróxido de cálcio,além dos produtos clorexidina, Sulfato de Neomicina+Bacitracina, PMCC, iodofórmio e hidróxido de cálcio em 24h, e pelo propilenoglicol, pastas iodoformadas e seus componentes, com exceção do iodofórmio, em 72h. No ensaio cometa, nenhuma pasta iodoformada danificou o DNA em ambos os tempos experimentais. Enquanto no GEMO, a pasta clorexidina mostrou efeito genotóxico. As pastas à base de hidróxido de cálcio e o hidróxido de cálcio causaram danos ao DNA nos dois ensaios. Concluiu-se que as pastas e componentes avaliados variaram quanto à capacidade de indução de citotoxicidade, extresse oxidativo e genotoxicidade. As pastas Guedes-Pinto, Maxitrol® e Sulfato de Neomicina+Bacitracina apresentaram melhor desempenho quanto à biocompatibilidade in vitro.

Orientador: José Roberto Cury Saad / Banca: Marcelo Ferrarezi de Andrade / Banca: Osmir Batista de Oliveira Junior / Banca: Paulo Afonso Silveira Francisconi / Banca: Luiz Alberto Formighieri / Resumo: A preservação e a restauração de dentes despolpados severamente debilitados é um procedimento complexo e relativamente imprevisível. Este estudo avaliou a resistência à fratura de raízes bovinas experimentalmente debilitadas, reconstruídas internamente com diferentes materiais restauradores em combinação com pinos pré-fabricados de fibra de vidro comparados com raízes íntegras restauradas com núcleo metálico fundido ou pino de fibra de vidro. Foram selecionadas raízes de 120 (n=15) incisivos bovinos inferiores de dimensões semelhantes, dos quais, 90 foram internamente preparados para simular uma raiz debilitada. Todas as raízes foram preenchidas com diferentes materiais restauradores e os espécimes foram submetidos ao teste de resistência ao fracasso/ fratura com a aplicação de uma carga compressiva tangencial a um ângulo de 135º em relação ao longo eixo axial das raízes. Resultados indicaram diferenças estatisticamente significante entre os grupos. As raízes debilitadas restauradas com núcleo metálico fundido (grupo NMF-RD) demonstraram os mais baixos valores de resistência à fratura (107.7436 N), sendo estatisticamente diferentes dos demais grupos. As raízes íntegras restauradas com núcleo metálico fundido (NMF-RI) mostraram os maiores valores de resistência (362.3308 N), mas com diferenças estatisticamente significantes somente quando comparadas às raízes debilitadas restauradas com cimento resinoso dual (Variolink II, Ivoclar Vivadent - grupo Vario-RD), cimento resinoso autopolimerizável (Multilink, Ivoclar Vivadent - grupo Multi-RD) e cimento de ionômero de vidro modificado por resina (Vitremer, 3M ESPE - grupo Vitre-RD) associado com pino de fibra de vidro... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The preservation and restoration of severely weakened pulpless teeth is a difficult and relatively unpredictable procedure. This study evaluated the resistance to fracture of experimentally weakened bovine roots internally reconstructed with different filling materials in combination with prefabricated fiberglass posts compared with restored roots that were relatively intact. The roots of 120 mandibular bovine incisors with similar bulks were selected. Of these, 90 were internally prepared to standardized dimensions, thereby simulating weakness. All roots were filled with different restorative materials. The specimens were submitted to the fracture resistance testing with the application of a tangential compressive loading at an angle of 135º in relation to the long axes of the roots. Results indicated statistically significant differences among the groups. The weakened roots restored with the cast post-core (group NMF-RD) demonstrated the lowest fracture resistance values (107.7436 N), which were significantly different from the averages of the remaining groups. The healthy roots restored with the cast post-core (group NMF-RI) showed the highest values (362.3308 N), but statistically significant differences were observed only when compared with weakened roots restored by the dual-cured resin cements (Variolink II, Ivoclar Vivadent - group Vario-RD), chemically cured resin cements (Multilink, Ivoclar Vivadent - group Multi-RD) and resin-modified glass-ionomer cement (Vitremer, 3M ESPE - group Vitre-RD) associated with fiberglass posts. There was not statistically significant differences among the groups of the weakened roots restored with self-adhesive universal resin cement (RelyX Unicem, 3M ESPE - group Unicem-RD), composite resin (Tetric 15 Ceram, Ivoclar Vivadent - group Tetric-RD), group Vitre-RD and group Vario-RD... (Complete abstract click electronic access below) / Doutor

Eurocoating, Italy, is a company that works in the biomedical sector. They have for a long time created prostheses from CAD files achieved from customers, and now they want to build their own expertise about the design. The thesis work was a part of a three year long collaborative research project between Eurocoating and University of Trento that was aiming to investigate the prostheses with open-porous surface and trabecular structure, created by Selective Laser Melting. The purpose of the thesis was to investigate and characterize 30 different trabecular structures of Ti-6Al-4V, fabricated by Selective Laser Melting. That includes investigation the effect on the morphology and porosity fraction caused by the manufacturing and the effect on mechanical and physical properties due to the different characterizations of the structures. The thesis work had its foundation in literature studies to receive deep knowledge about the subject. Practical tests were performed to investigate mechanical behaviour under compressive and tensile loading, static friction and wear resistance. The findings from these tests were compared to the porosity fraction and the morphological characterizations. The result stated that the porosity fraction was lower than the designed porosity, and that is was strongly influenced by size of the voids and struts. The strut thickness was higher than the design values, especially on the lateral surface, while the voids size were approximately as designed. Result from the compression test showed a trend of decreasing stiffness and strength with increasing porosity fraction. Also structures with same porosity fraction could have a wide range in mechanical properties which indicates high dependence on the morphological geometry i.e. pore size and shape, strut size and pore distribution. Comparisons between tensile and compression behaviour stated that the structures had a lower strength but a significant higher stiffness in tensile load. All structures from the wear test showed a good resistance while the results from the friction test needs further investigation to be fully understood. The physical and mechanical properties of the trabecular structures was found to be close to those of cortical and trabecular bone in porosity, stiffness and strength. There is a range of variations leading to possibilities to adopt the application depending on customer. Thus, these can be considered as promising structures used biomedical application to optimize osseointegration and secondary long term fixation.

Photogrammetrische Methoden gewinnen zunehmend an Bedeutung im bau­tech­nischen Versuchswesen. Die Auswertung von Bildsequenzen ermöglicht eine kontakt­lose, flächenhafte, hochaufgelöste und hochgenaue Veränderungs­detek­tion von Ober­flächen in der Materialprüfung und Bauwerksüberwachung. Diese Arbeit behan­delt einige Aspekte der Deformationsanalyse auf Basis von Bild­sequenzen mit Hilfe triangulierter Verschiebungsfelder. Zunächst wird auf Unter­suchungen zu Defor­ma­tionen ebener Objektoberflächen, die mit mono­kularen Bild­sequenzen beo­bachtet wurden, eingegangen. Im weiteren Verlauf wird auf Stereobildsequenzen über­ge­gangen, die Deformations­mes­sungen für beliebige Ober­flächen erlauben. Im ersten Teil der Arbeit wird gezeigt, wie Verschiebungsfelder in monokularen Bild­sequenzen bestimmt werden können. Die Bildpunkte, an welche die Verschie­bungen geknüpft sind, werden zu einem Dreiecksnetz trianguliert. Jedes einzelne Dreieck wird auf Änderungen zu der Referenzepoche, die als die erste Epoche ohne jegliche Defor­mation definiert ist, untersucht. Ein gängiges Verfahren zur Analyse solcher Verän­derungen ist die Berechnung von Haupt­dehnungen für jedes Dreieck. Schwell­werte können zur Erkennung deformierter Bereiche und die farbkodierte Darstellung der Hauptdehnungen für eine visuelle Betrachtung genutzt werden. In den räumlich verteilten Hauptdehnungen sowie im zeitlichen Ablauf treten Rausch­effekte auf. Deshalb werden verschiedene Filtermethoden zur Rausch­unter­drückung untersucht. Dabei kommt ein Filter zum Einsatz, der gleichzeitig in der räumlichen sowie der zeitlichen Dimension filtert. Es werden aber auch Filter unter­sucht, die in beiden Dimensionen getrennt filtern. Aus den Hauptdehnungen können nicht direkt Rissbreiten abgeleitet werden. Diese spielen für die Materialprüfung im Bauwesen allerdings eine wichtige Rolle, wes­wegen sich diese Arbeit auch mit der Berechnung von Riss­breiten in Dreiecks­netzen befasst. Als deformierte Dreiecke werden diejenigen detektiert, deren Hauptdehnung einen Schwellwert überschreiten. Für diese Kandidaten werden im Folgenden Rissbreiten bestimmt. Drei verschiedene Verfahren für die Ermittlung von Rissbreiten werden vorgestellt und verglichen. Die Dehnbarkeit faserbewehrter Komposite, die unter anderem zur Verstärkung von Mauern und anderen Bauwerken verwendet werden, wird bei Belastung durch die Bildung multipler Rissstrukturen gewährleistet. Auf Grund dessen widmet sich ein weiterer Teil der Dissertation der Auswertung multipler Riss­strukturen. Hierzu werden dichte Verschiebungsfelder berechnet. Dann wird zunächst eine Auswahl der verfolgten Punkte genutzt, um ein grobes Dreiecks­netz zu generieren. Deformierte Dreiecke der ausgedünnten triangu­lierten Punktmenge werden mit dem Betrag des relativen Trans­lations­vektors, der als Deformations­maß eingeführt wird, detektiert. Eine iterative Verdichtung des Dreiecknetzes in defor­mierten Bereichen ermöglicht die Auswertung enger Riss­muster. Zudem erlaubt eine Ausgleichung, dass nicht-triangulierte Punkte des dichten Verschie­bungs­feldes in die Rissbreiten­berechnung einbe­zogen werden können. Ein weiterer Bestandteil der Arbeit ist die Betrachtung unebener Oberflächen, die mit Stereokamerasystemen beobachtet werden. Dazu werden die Algorithmen für die zweidimensionale Auswertung entsprechend übertragen und erweitert. Auf Basis von Verschiebungsfeldern dreidimensionaler Punkte wird auch hier ein Dreiecksnetz zur Änderungsdetektion genutzt. So wird am Beispiel von dynamischen Dehnungstests an zylindrischen Probe­körpern ein Algorithmus zur Rissbreitenmessung auf nicht ebenen Ober­flächen vorge­stellt. Dabei wird angenommen, dass die Defor­mationen ausschließlich tangential zur Oberfläche auftreten. Dies erlaubt die Transformation (Kongruenz­abbildung) der Dreiecke in einen zwei­dimen­sionalen Raum und auch eine zwei­dimensionale Auswertung. Außerdem wird eine Methode zur Berechnung des dreidimensionalen Riss­öffnungs­vektors präsentiert. Dieses Verfahren ist eine Erweiterung zum vorher­gehenden Algorithmus und erlaubt zudem die Vermessung vertikaler Defor­ma­tionen. Defor­mierte Dreiecke im trian­gulierten dreidimensionalen Verschie­bungs­feld werden mit Hilfe des zwei­dimen­sionalen Relativ­translations­vektor­betrags der in den zwei­dimen­sionalen Raum transformierten Dreiecke detek­tiert. Anschließend folgt für alle defor­mierten Dreiecke durch Hinzunahme min­des­tens eines undeformierten Nachbar­dreiecks die Berechnung eines drei­dimen­sionalen relativen Trans­lations­vektors, mit Hilfe dessen die Komponenten des Riss­öffnungsvektors ermittelt werden.:Kurzfassung iii Abstract v 1. Einführung 1 1.1. Struktur der Arbeit 1 1.2. Motivation 2 1.3. Verwandte Arbeiten 4 1.4. Ziele der Arbeit 7 2. Photogrammetrische Deformationsmessung in monokularen Bildsequenzen 8 2.1. Filtermethoden in Dreiecksnetzen 9 2.2. Rissbreitenberechnung mit Hilfe von Dreiecksnetzen 19 2.3. Strategie zur Rissbreitenmessung für multiple Rissstrukturen 29 3. Photogrammetrische Deformationsmessung in Stereobildsequenzen 50 3.1. Rissbreitenberechnung für tangentiale Deformationen auf nicht ebenen Oberflächen mit gegebenem 3D-Verschiebungsfeld 51 3.2. Berechnung des dreidimensionalen Rissöffnungsvektors bei gegebenem 3D-Verschiebungsfeld 59 4. Diskussion 70 5. Ausblick 77 5.1. Bestimmung der Anzahl der Risse 77 5.2. Rissspitzenbestimmung und -verfolgung 78 5.3. Anwendung der entwickelten Algorithmen auf Voxeldaten 78 5.4. Modellerweiterung durch Relativrotation 82 5.5. Genauigkeitssteigerungen für die Rissposition 82 5.6 Verbesserung der Rissnormalenschätzung 82 Literaturverzeichnis 83 Abkürzungsverzeichnis 89 Tabellenverzeichnis 90 Abbildungsverzeichnis 90 / Photogrammetric methods are gaining importance in civil engineering material testing and structural health monitoring. The analysis of image sequences ensures an extensive change detection of surfaces with a high spatial resolution and a high accuracy. This thesis deals with some aspects of deformation analysis based on image sequences and triangulated displacement fields. At the beginning, the examination of planar surfaces of specimens observed with monocular image sequences is considered. Later, a transition to stereo image sequences is given because they allow a deformation measurement of arbitrary surfaces. The first part of the thesis shows how to derive displacement fields from monocular image sequences. The matching points corresponding to the displace­ments are triangulated into a mesh. Each triangle is compared to the reference epoch which is defined as the first time epoch under zero load without any deformation. As a current method, principal strains are used to detect deformations. Thresholds can be used to find deformed areas. In addition, color-coded maps of the principal strains are helpful for a visual detection. In the field of the principal strains, noise effects appear in the spatial as well as in the temporal domain. Therefore, different filter methods are applied to reduce noise. In addition to filter techniques that are applied independently in the time and the spatial domain, a combined spatio-temporal filter is tested. Crack widths cannot be derived directly from principal strains but crack widths are an important issue in civil engineering material testing. For this reason, this thesis also gives attention to the computation of crack widths in triangle meshes. The principal strains of the triangles are tested for exceeding a threshold to detect deformed triangles. For the deformed triangles, crack widths are computed. Three different methods for the crack width determination are presented and compared. Multiple cracking ensures the ductility of loaded fiber-reinforced composites used to strengthen walls among other things. Therefore, another part of the dissertation deals with the photogrammetric analysis of multiple crack patterns. Herein, dense displacement fields are computed. Then, a thinned-out set of points is triangulated into a mesh. For each triangle, the norm of the relative translations vector defined as a new quantity to detect deformations is deter­mined and used to find cracked triangles. The mesh is densified iteratively in deformed areas to ensure an analysis of narrow crack structures. In addition, a least squares algorithm is presented which allows that points of the displace­ment field, that are not part of the mesh, can be included in the crack width computation. A further part of the dissertation deals with non-planar surfaces observed with stereo camera systems. The algorithms of the two dimensional analysis are adapted and extended to use them for these applications. These methods are based on three dimensional displacement fields and also use triangle meshes to detect deformed areas. One algorithm concentrates on the crack width measurement of non-planar surfaces with deformations that are only tangential to the surface. The method is applied on a cylindrical specimen in a dynamic tension test. The assumption that deformations are tangential to the surface allows the transformation of the triangles in the two dimensional space and also a two dimensional analysis. In addition, an algorithm for the computation of the three dimensional crack opening vectors is presented. This method is an extension to the foregoing algorithm and is capable of measuring vertical deformations. To find deformed triangles in the triangulated three dimensional displacement field, the triangles are transformed in the two dimensional space in a first step. In a second step, the norm of the two dimensional relative translation vector is determined and tested if it exceeds a threshold. In the following, for each deformed triangle, the three dimensional relative translation vector is computed using a undeformed neighbor triangle. At the end, the three dimensional relative translation vectors can be transformed to the crack opening vectors.:Kurzfassung iii Abstract v 1. Einführung 1 1.1. Struktur der Arbeit 1 1.2. Motivation 2 1.3. Verwandte Arbeiten 4 1.4. Ziele der Arbeit 7 2. Photogrammetrische Deformationsmessung in monokularen Bildsequenzen 8 2.1. Filtermethoden in Dreiecksnetzen 9 2.2. Rissbreitenberechnung mit Hilfe von Dreiecksnetzen 19 2.3. Strategie zur Rissbreitenmessung für multiple Rissstrukturen 29 3. Photogrammetrische Deformationsmessung in Stereobildsequenzen 50 3.1. Rissbreitenberechnung für tangentiale Deformationen auf nicht ebenen Oberflächen mit gegebenem 3D-Verschiebungsfeld 51 3.2. Berechnung des dreidimensionalen Rissöffnungsvektors bei gegebenem 3D-Verschiebungsfeld 59 4. Diskussion 70 5. Ausblick 77 5.1. Bestimmung der Anzahl der Risse 77 5.2. Rissspitzenbestimmung und -verfolgung 78 5.3. Anwendung der entwickelten Algorithmen auf Voxeldaten 78 5.4. Modellerweiterung durch Relativrotation 82 5.5. Genauigkeitssteigerungen für die Rissposition 82 5.6 Verbesserung der Rissnormalenschätzung 82 Literaturverzeichnis 83 Abkürzungsverzeichnis 89 Tabellenverzeichnis 90 Abbildungsverzeichnis 90

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Le futur Réacteur d'irradiation Jules Horowitz (RJH) constituera à partir de 2016 sur le site du CEA Cadarache (France) un outil unique dédié aux besoins de l'industrie et de la recherche dans le domaine de l'énergie nucléaire. La qualité des programmes de recherche qui seront conduits dans le RJH dépendra pour une grande part de la bonne connaissance et de la maîtrise des conditions expérimentales dans les canaux d'essais. Dans ce contexte, le CEA et Aix-Marseille Université conduisent conjointement un projet scientifique et technique baptisé IN-CORE. Ce projet a pour but d'améliorer la connaissance des flux neutroniques et photoniques du cœur du réacteur RJH. Un des enjeux est donc d'identifier les détecteurs capables de mesurer de tels flux et de déterminer les méthodes d'interprétation des signaux les plus appropriées. Les travaux de thèse s'inscrivent dans ce programme ambitieux et ont pour objectif d'étudier les potentialités et l'intérêt de la combinaison des mesures des rayonnements dans la perspective d'une meilleure évaluation des niveaux de flux neutroniques, rayonnement gamma et d'échauffement nucléaire dans les emplacements expérimentaux du RJH. Une première étape du projet a consisté à réaliser et exploiter un dispositif de mesure appelé CARMEN-1, adapté à la cartographie des conditions d'irradiation du réacteur OSIRIS (France). Cette expérience a été l'occasion de tester l'ensemble des détecteurs des flux de rayonnement susceptibles de répondre aux besoins du RJH, notamment ceux récemment développés. / A new Material Testing Reactor (MTR), the Jules Horowitz Reactor (JHR), is under construction at the CEA Cadarache (French Alternatives Energies and Atomic Energy Commission). From 2016 this new MTR will be a new facility for the nuclear research on materials and fuels. The quality of the experiments to be conducted in this reactor is largely linked to the good knowledge of the irradiation conditions. Since 2009, a new research program called IN-CORE “Instrumentation for Nuclear radiations and Calorimetry Online in Reactor” is under progress between CEA and Aix-Marseille University. This program aims to improve knowledge of the neutron and photon fluxes in the RJH core. One of the challenges is to identify sensors able to measure such fluxes in JHR experimental conditions and to determine how to analyse the signals delivered by these sensors with the most appropriate methods. The thesis is part of this ambitious program and aims to study the potential and the interest of the combination of radiation measurements in the prospect of a better assessment of the levels of neutron flux, gamma radiation and nuclear heating in the JHR experimental locations. The first step of IN-CORE program was to develop and operate an instrumented device called CARMEN-1 adapted to the mapping of the OSIRIS reactor (France). This experiment was the opportunity to test all the radiation sensors which could meet the needs of JHR, including recently developed sensors.

Pesquisas sobre a tenacidade à fratura dos aços ferríticos mostram uma grande dispersão dos resultados quando avaliados na região de transição dúctil-fragil. Esta dispersão é fortemente influenciada pela temperatura de ensaio, dimensões e geometria dos corpos-de-prova e também pelo nível de restrições plástica na ponta da trinca. Tais fatores dificultam a previsão, a partir de valores experimentais, de valores de tenacidade à fratura de aços ferríticos para aplicações em casos práticos. Uma forma de contornar essa dificuldade é através do uso das curvas de referencia, descritas no Código ASME. Estas curvas representam envoltórias inferiores de tenacidade à fratura obtida a partir de ensaios envolvendo diversos tipos de aços. Portanto os valores de tenacidade estabelecidos por essas curvas são, em geral, muito conservadores. Então foi proposta pela ASTM uma nova metodologia, chamada curva Mestra, que trata estatisticamente o comportamento à fratura dos aços ferríticos na região de transição e caracteriza um material em particular, através de um parâmetro denominado Temperatura de Referencia (T0). Nesta pesquisa, avaliou-se a influencia da sensibilidade dos parâmetros: Kmin, m e M envolvidos no procedimento do calculo de um parâmetro denominado temperatura de referencia. (T0). A metodologia da curva mestra foi aplicada através dos dados (experimentos) do euro-teste , para as temperaturas: -91 ºC, -60°C, -40°C e 20°C . Em análises de sensibilidade aos parâmetros com os seguintes valores kmin = 0, 10, 30; m= (3), (3,5), (4,5), (5,0) e M = 40, 50, 60. Os resultados apresentados são compatíveis comprovando a eficiência da metodologia para avaliação da tenacidade à fratura dos aços ferríticos na região de transição. Portanto, nestas condições, podemos afirmar que o conceito da curva mestra foi, realmente validado. / The caracterization of the fracture behavior in the ductile-to-brittle transition for ferritic steels is a hard task because fracture toughness is a strong function of temperature in the transition, with the toughness values increasing rapidly over a relatively narrow temperature baud/range and therefore cannot be easily used to evaluate integrity in structural components because of the uncertainty in how to handle these teste results. To overcome this problem in practice, the ASME code has provided reference curves that give estimates of toughness versus temperature. These curves represent lower envelopes to a large set of fracture toughness experimental data for several heats of steel . Therefore, the fracture toughness values obtained from these curves are in general too conservative. In the last decade, a new methodology, formalized in the ASTM standard method E1921-97, has revolutionized the approach used to caracterize transition fracture behavior and has given a rationale for treating the several factors that influence the scatter in the results. Statistical models are used to define a transition curve, called Master Curve, and the transition temperature of a given material is stated by a parameter called reference temperature (T0). In this research, it was evaluated the sensitivity influence of the parameter: Kmin, m and M, involved in the to measurement procedure. The master curve methodology was applied over the data (experiments) of EuroTest for the following temperatures: - 91°C, -60°C, -40°C and -20°C. A parameters sensitivity analysis was made with following values: Kmin=0, 10, 30; m=(3), (3,5), (4,5), (5,0) and M=40, 50, 60. The results are compatible, which confirm the efficiency of the methodology for evaluating the toughness to ferritic steel fracture in the transition region. Therefore, in these conditions, we can state the master curve concept has indeed been validated.

Virgin aggregate is being used faster than it is being made available creating a foreseeable shortage in the future. Despite this trend, the availability of demolished concrete for use as recycled concrete aggregate (RCA) is increasing. Using this waste concrete as RCA conserves virgin aggregate, reduces the impact on landfills, decreases energy consumption and can provide cost savings. However, there are still many unanswered questions on the beneficial use of RCA in concrete pavements. This research addresses the many technical and cost-effective concerns regarding the use of RCA in concrete pavements by identifying concrete mixture and proportioning designs suitable for jointed plain concrete pavements; constructing test sections using varying amounts of RCA; monitoring performance through testing, condition surveys and sensor data; modeling RCA pavement performance; and predicting life cycle costs. The research was carried out as a partnership between the Centre for Pavement and Transportation Technology (CPATT) at the University of Waterloo, the Cement Association of Canada, Dufferin Construction, and the Natural Sciences and Engineering Research Council of Canada. The literature review provides an overview of sustainability and key performance indicators, the material properties of RCA both as an aggregate and in concrete, concrete mixture and proportioning designs with RCA, performance of existing RCA pavements, and the implementation of RCA highlighting some examples where RCA has been used successfully. Twelve preliminary mixes were developed using three total cementitious contents amounts of 315 kg/m3, 330 kg/m3, and 345 kg/m3 to determine four suitable mixes with varying coarse RCA contents (0%, 15%, 30% and 50%) to place at the CPATT test track. At 28-days, all of the twelve mixes exceed the 30 MPa design strength. Four test sections containing 0%, 15%, 30% and 50% coarse RCA were constructed in June 2007. The test sections had identical cross sections consisting of 250 mm portland cement concrete (PCC), 100 mm asphalt-stabilized OGDL and a 450 mm granular base. For each coarse RCA content, one slab was instrumented with six vibrating wire concrete embedment strain gages to measure long-term longitudinal and transverse strain due to environmental changes, two vibrating wire vertical extensometers to monitor slab curling and warping, two vibrating wire inter-panel extensometers to monitor joint movement, and two maturity meters to measure maturity and temperature. Quality assurance and quality control (QA/QC) testing showed that the mixes containing RCA exhibited similar or improved performance when compared to the conventional concrete for compressive and flexural strength, freeze-thaw durability and coefficient of thermal expansion. Pavement performance of the four test sections was evaluated using visual surveys following the Ontario Ministry of Transportation’s Manual for Condition rating of Rigid Pavements. Nine pavement evaluations have been performed every two to four months since construction. All test sections are in excellent condition with pavement condition index (PCI) values greater than 85 after two years in-service and approximately three hundred thousand Equivalent Single Axle Loads. Sensor data from the strain gauges, and vertical and inter-panel extensometers are providing consistent results between the test sections. Long-term performance modeling using the Mechanistic-Empirical Pavement Design Guide (ME-PDG) showed improved performance with respect to cracked slabs, joint faulting, and pavement roughness as the RCA content increased. Multivariable sensitivity analysis showed that the performance results were sensitive to CTE, unit weight, joint spacing, edge support, surface absorption, and dowel bar diameter. Life cycle cost analysis (LCCA) illustrated the savings that can be expected using RCA as a replacement aggregate source as the cost of virgin aggregate increase as the sources becomes depleted. Multivariable sensitivity analysis showed that the LCCA results were sensitive to construction costs, discount rate, and maintenance and rehabilitation quantities.

Virgin aggregate is being used faster than it is being made available creating a foreseeable shortage in the future. Despite this trend, the availability of demolished concrete for use as recycled concrete aggregate (RCA) is increasing. Using this waste concrete as RCA conserves virgin aggregate, reduces the impact on landfills, decreases energy consumption and can provide cost savings. However, there are still many unanswered questions on the beneficial use of RCA in concrete pavements. This research addresses the many technical and cost-effective concerns regarding the use of RCA in concrete pavements by identifying concrete mixture and proportioning designs suitable for jointed plain concrete pavements; constructing test sections using varying amounts of RCA; monitoring performance through testing, condition surveys and sensor data; modeling RCA pavement performance; and predicting life cycle costs. The research was carried out as a partnership between the Centre for Pavement and Transportation Technology (CPATT) at the University of Waterloo, the Cement Association of Canada, Dufferin Construction, and the Natural Sciences and Engineering Research Council of Canada. The literature review provides an overview of sustainability and key performance indicators, the material properties of RCA both as an aggregate and in concrete, concrete mixture and proportioning designs with RCA, performance of existing RCA pavements, and the implementation of RCA highlighting some examples where RCA has been used successfully. Twelve preliminary mixes were developed using three total cementitious contents amounts of 315 kg/m3, 330 kg/m3, and 345 kg/m3 to determine four suitable mixes with varying coarse RCA contents (0%, 15%, 30% and 50%) to place at the CPATT test track. At 28-days, all of the twelve mixes exceed the 30 MPa design strength. Four test sections containing 0%, 15%, 30% and 50% coarse RCA were constructed in June 2007. The test sections had identical cross sections consisting of 250 mm portland cement concrete (PCC), 100 mm asphalt-stabilized OGDL and a 450 mm granular base. For each coarse RCA content, one slab was instrumented with six vibrating wire concrete embedment strain gages to measure long-term longitudinal and transverse strain due to environmental changes, two vibrating wire vertical extensometers to monitor slab curling and warping, two vibrating wire inter-panel extensometers to monitor joint movement, and two maturity meters to measure maturity and temperature. Quality assurance and quality control (QA/QC) testing showed that the mixes containing RCA exhibited similar or improved performance when compared to the conventional concrete for compressive and flexural strength, freeze-thaw durability and coefficient of thermal expansion. Pavement performance of the four test sections was evaluated using visual surveys following the Ontario Ministry of Transportation’s Manual for Condition rating of Rigid Pavements. Nine pavement evaluations have been performed every two to four months since construction. All test sections are in excellent condition with pavement condition index (PCI) values greater than 85 after two years in-service and approximately three hundred thousand Equivalent Single Axle Loads. Sensor data from the strain gauges, and vertical and inter-panel extensometers are providing consistent results between the test sections. Long-term performance modeling using the Mechanistic-Empirical Pavement Design Guide (ME-PDG) showed improved performance with respect to cracked slabs, joint faulting, and pavement roughness as the RCA content increased. Multivariable sensitivity analysis showed that the performance results were sensitive to CTE, unit weight, joint spacing, edge support, surface absorption, and dowel bar diameter. Life cycle cost analysis (LCCA) illustrated the savings that can be expected using RCA as a replacement aggregate source as the cost of virgin aggregate increase as the sources becomes depleted. Multivariable sensitivity analysis showed that the LCCA results were sensitive to construction costs, discount rate, and maintenance and rehabilitation quantities.