Submitted by Marcos Wanderley (marcos.wanderley@ufcg.edu.br) on 2018-07-25T22:10:41Z No. of bitstreams: 1 LEYLLANNE RENALLE BATISTA DE ALMEIDA - DISSERTAÇÃO(PPGEPM) 2017.pdf: 12325381 bytes, checksum: fce49fc6ad696f06078e766798c43c30 (MD5) / Made available in DSpace on 2018-07-25T22:10:41Z (GMT). No. of bitstreams: 1 LEYLLANNE RENALLE BATISTA DE ALMEIDA - DISSERTAÇÃO(PPGEPM) 2017.pdf: 12325381 bytes, checksum: fce49fc6ad696f06078e766798c43c30 (MD5) / A ampla utilização do método sísmico de prospecção na indústria de petróleo para gerar imagens das estruturas geológicas que encontram-se em subsuperfície e para o monitoramento dos reservatórios de petróleo torna essencial o conhecimento das propriedades petrofísicas e dos fatores que as afetam. Neste contexto, esta pesquisa tem como objetivo realizar o estudo petrofísico e petrográfico de trinta amostras de rochas sedimentares (arenitos e calcários), provenientes de formações estadunidenses, consideradas padrões na indústria. Foram realizados ensaios de caracterização petrofísica convencional, por métodos laboratoriais, empíricos - através dos modelos de substituição de fluidos - e simulações por modelos computacionais, utilizando os softwares Avizo Fire 8.1 e COMSOL Multiphysics 5.1, bem como a análise composicional a partir da difratometria de raios X e da descrição de lâminas delgadas em microscópio ótico. Os ensaios petrofísicos foram realizados em diferentes condições de pressão e saturação. As propriedades petrofísicas foram influenciadas por diversos parâmetros, que se diferenciam de acordo com o tipo litológico da rocha. A saturação das rochas não atingiu 90%, sendo para as rochas de matriz dolomítica muito inferior quando saturadas com óleo, possivelmente devido às mesmas serem molháveis a água. A saturação fluida influencia definitivamente nas propriedades elásticas das rochas em ambos os métodos estudados. Quando saturados com óleo, a maioria dos plugues apresentaram velocidades compressionais maiores em comparação às outras condições de saturação (seca ou saturada com água). Os modelos de Gassmann e Brown & Korringa mostraram-se mais representativos para as ondas compressionais, sendo em alguns casos eficientes também para as cisalhantes. O modelo de Biot mostrou-se mais eficiente para as ondas cisalhantes, principalmente nos arenitos. O método computacional mostrou-se eficaz visto que a velocidade compressional, pelo menos para um dos pontos receptores escohidos, se aproxima ou coincide com o valor medido laboratorialmente. Os resultados obtidos mostram que o conjunto de amostras estudado apresenta um bom potencial para reservatório. A composição mineralógica por DRX apresentou um bom ajuste com a densidade de grãos medidas convencionalmente. / The wide use of seismic prospecting method in the oil industry to generate images of geological structures that are found in subsurface and to the monitoring of petroleum reservoirs makes it essential to the knowledge of the petrophysical properties and the factors that affect them. In this context, this research aims to carry out the petrophysical and petrographical study of 30 samples of sedimentary rocks (sandstones and limestones) from American formations, considered standards in the industry. Petrophysical characterization tests were carried out by conventional laboratory methods, empirical-through fluid-replacement models and simulations by computer models, using the software Avizo Fire 8.1 and COMSOL Multiphysics 5.1, as well as the compositional analysis from the x-ray diffractometry and thin sections description in optical microscope. The petrophysical tests were performed under different conditions of pressure and fluid saturation. The petrophysical properties were influenced by several parameters, which differ according to the lithological rock type. The saturation of rocks not reached 90%, being much lower for dolomitic matrix rocks when saturated with oil, possibly due to their water wettability. Fluid saturation influences definitely in elastic properties of rocks in both methods studied. When saturated with oil most of the samples show higher compressional velocities as compared to other conditions of saturation (dry or saturated with water). The models of Gassmann and Brown & Korringa were more representative for the compressionais waves, being efficient in some cases also for the shear ones. Biot model proved to be more efficient for shear waves, especially in sandstones. The computational method proved effective as the compressional velocity, at least for one of the receivers, approaches or matches the value measured in the laboratory. The results obtained show that the set of samples studied presents good potential for reservoir. The mineralogical composition by DRX presented a good fit with the grain density measured conventionally.

Os testes utilizados rotineiramente na avaliação de danos mecânicos, danos causados por insetos e danos por deterioração de tecidos em sementes de soja e de milho são destrutivos, impossibilitando a associação dos resultados obtidos com os testes fisiológicos (germinação e vigor). Dessa forma, a avaliação da qualidade de sementes por meio de análise de imagens tem despertado interesse da pesquisa, devido ao fato de serem técnicas rápidas e não destrutivas, permitindo tal associação. Dentre as técnicas de análise de imagens existentes, as técnicas de microtomografia computadorizada de raios X (micro-TC) e imagem por ressonância magnética (IRM) tem se mostrado promissoras na pesquisa com sementes, por gerarem imagens tridimensionais, que permitem verificar, com precisão, a localização dos danos internos nas sementes. Assim, o objetivo deste trabalho foi utilizar as técnicas de micro-TC e IRM para avaliar danos internos em sementes de milho e de soja, verificar suas relações com a germinação e compará-las a técnica de raios X, que vem sendo utilizada na pesquisa com sementes. Para tanto foram selecionadas previamente, 32 sementes de soja e 30 sementes de milho, que foram submetidas aos testes de raios X, micro-TC e IRM, para obtenção das imagens e, posteriormente, ao teste de germinação, para associar os resultados obtidos com o desempenho das sementes. Pode-se concluir para as sementes de soja que as três técnicas se mostraram eficientes na detecção de danos nas sementes. Por outro lado, para as sementes de milho, pode-se haver necessidade de utilização das técnicas de micro-TC e IRM para avaliar, com maior precisão, a morfologia interna das sementes. / The current tests used in the evaluation of mechanical, insect, and tissue damage in soybean and corn seeds are destructive, making it impossible to associate those with the results obtained with physiological tests (germination and vigor).Therefore, evaluation of the seed quality by imaging analysis techniques aroused interest in seed research for being fast and non-destructive techniques, allowing association with physiological tests. X-ray computerized microtomography (micro-CT) and magnetic resonance imaging (MRI) seem promising techniques due to the fact they generate three-dimensional imagens allowing more accurately evaluation of the seed\'s internal morphology. The objective of this study was to use the micro-CT and MRI techniques to evaluate internal morphology of soybean and corn seeds, correlate their relationship with the physiological test (germination test) and to compare them with the X-ray technique, which has been used in seed research. For that 32 soybena seeds and 30 corn seeds were selected. Seeds were tested with X-ray, micro-CT, MRI, to obtain the images. Then germination test was conducted to associate the results obtained with the performance of the seeds. Overall, the three techniques were efficient in detecting damage in soybean seeds. On the other hand for corn, it may be necessary to use the micro-CT and MRI techniques to evaluate more accurately the internal morphology of the seeds.

Different tracing techniques of the subperiosteal and endosteal contours (manual, automatic, semi-automatic) or their combinations taken along femoral length in adult individuals can produce different values of cross-sectional geometric (CSG) parameters. Various tracing techniques are widely used in CSG studies of non-adult individuals as well, however, the accuracy of CSG parameters estimated along femoral diaphysis is not yet known for non-adult individuals. In this study, we investigate whether the manual tracing of the subperiosteal and endosteal contours taken at 80% of the femoral diaphyseal length in non-adult individuals can be replaced by another type of tracing in relation to CSG parameters estimation. We examine the effect of anatomical localization on accuracy of the CSG parameters estimated in non-adult individuals femora. We digitized the subperiosteal and endosteal contours in the micro-CT scans from femoral diaphyseal cross-sections in Early Medieval sample of non-adult individuals (N = 46). The digitization and computation of CSG parameters were made in Fiji software with EPJMacro implementation. The assessment of estimates' accuracy was expressed by percentage prediction error (%PE) and limits of agreement. Five percent of CSG parameter obtained from manually traced contours was...

<p></p><p>Additive Manufacturing (AM) allows for the creation of elements with novel forms and functions. Utilizing AM in development of components of civil infrastructure allows for achieving more advanced, innovative, and unique performance characteristics. The research presented in this dissertation is focused on development of a better understanding of the fabrication challenges and opportunities in AM of cement-based materials. Specifically, challenges related to printability and opportunities offered by 3D-printing technology, including ability to fabricate intricate structures and generate unique and enhanced mechanical responses have been explored. Three aspects related to 3D-printing of cement-based materials were investigated. These aspects include: fresh stability of 3D-printed elements in relation to materials rheological properties, microstructural characteristics of the interfaces induced during the 3D-printing process, and the mechanical response of 3D-printed elements with bio-inspired design of the materials’ architecture. This research aims to contribute to development of new pathways to obtain stability in freshly 3D-printed elements by determining the rheological properties of material that control the ability to fabricate elements in a layer-by-layer manner, followed by the understanding of the microstructural features of the 3D-printed hardened cement paste elements including the interfaces and the pore network. This research also introduces a new approach to enhance the mechanical response of the 3D-printed elements by controlling the spatial arrangement of individual filaments (i.e., materials’ architecture) and by harnessing the weak interfaces that are induced by the 3D-printing process. </p><br><p></p>

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The viscoelastic behavior of concrete, nearly completely attributable to changes in properties in the cement paste, is an ongoing area of research with the objective of avoiding unpredictable response and potentially failure of concrete structures. This research explores the elastic and viscoelastic response in cement paste beams using relaxation testing, with and without strain reversals in the load history. It was seen that strain reversal imparts significant changes in mechanical response, retarding load relaxation. Companion beams were tested for chemical composition at varying depths in the beam section and the results were compared to those of control specimens not subject to stress. Results indicate significant variations in composition implying that stress accelerates the hydration process. The reasons behind the acceleration are discussed and incorporated into a preliminary solidification-dissolution model for beam relaxation. The model, though in need of improvement through further research, shows promise in potentially predicting relaxation in cement paste and by extension, in concrete structures. / Ph. D.

The objective of this thesis is to provide an improved characterization of porous scaffolds. A more focused objective is to provide a computational model simulating the cell mediated resorption process of resorbable bone substitutes. The thesis is structured in three scientific manuscripts. The first manuscript used fuzzy-based image treatment methods to analyse images generated by micro-computed tomography. From the literature, it is known that the fuzzy-based method helps to improve the accuracy of the characterization, in particular for scaffolds featuring a relatively small pore size. In addition, a new algorithm was introduced to determine both pore and interconnection sizes. The surface area of bone substitutes was quantified by using marching cube algorithm. Besides, the so-called Lattice Boltzmann method was used to characterize the permeability of the investigated scaffolds. Scaffolds made of [béta]-tricalcium phosphate ([béta]-Ca[subscript 3](PO[subscript 4])[subscript 2]) and presenting a constant porosity and four variable pore sizes were examined. The average pore size (diameter) of the four bone substitute groups (denominated with a letter from group A to D) was measured to be 170.3«1.7, 217.3«5.2, 415.8«18.8 and 972.3«10.9 [micro]m. Despite this significant change in pore size, the pore interconnection size only increased slightly, in the range of 61.7 to 85.2 [micro]m. The average porosity of the four groups was 52.3«1.5 %. The surface density of scaffolds decreased from 11.5 to 3.3 mm[superscript -1], when the pore size increased. The results revealed that the permeability of scaffolds is in the same order of magnitude and increased from 1.1?10[superscript -10] to 4.1?10[superscript -10] m[superscript 2] with increasing the pore size. The second manuscript was devoted to the use of subvoxelization algorithm and high-resolution scanner, in an attempt to further improve the accuracy of the results, in particular, of the small pore scaffolds. As expected, an increase of the image resolution from 15 to 7.5 [micro]m significantly eased the segmentation process and hence improved scaffold characterization. Subvoxelization also improved the results specifically in terms of interconnection sizes. Specifically, much smaller interconnection sizes were yielded after applying the subvoxelization process. For example, the mean interconnection size of small pore size groups, group A and B, dropped from 63 to 20 and 30 [micro]m, respectively. Furthermore, due to more details obtained from subvoxelization and high-resolution scanning, additional effects so called"boundary effects" were observed. The boundary effects can yield misleading results in terms of interconnection sizes. The means to reduce these effects were proposed. The third manuscript focused on the simulation and understanding of cell mediated resorption of bone graft substitutes. A computer model was developed to simulate the resorption process of four bone substitute groups. [mu]CT data and new"image processing" tools such as labelling and skeletonization were combined in an algorithm to perform the steps of resorption simulation algorithm. The proposed algorithm was verified by comparing simulation results with the analytical results of a simple geometry and biological in vivo data of bone substitutes. A correlation coefficient between the simulation results and both analytical and experimental data, was found to be larger than 0.9. Local resorption process revealed faster resorption in external region specifically at earlier resorption time. This finding is in agreement with the in vivo results. Two definitions were introduced to estimate the resorption rate; volume resorption rate and linear resorption rate. The volume resorption rate was proportional to accessible surface and decreased when the pore size increased, while the linear resorption rate was proportional to thickness of material and increased with increasing the pore size. In addition, the simulation results revealed no effect of resorption direction on resorption behaviour of substitutes. However, the resorption rate of small pore size samples was decreased with increasing the minimum interconnection size required for cell ingrowth, to 100 [micro]m. This thesis combined novel"image processing" tools and subvoxelization method to improve the characterization of porous bone substitutes used in the bone repair process. The improved characterization allowed a more accurate simulation process. The simulation data were consistent with previously obtained biological data of the same group and allows understanding the local resorption process. The available tools and results are expected to help with the design of optimal substitute for bone repair."--Résumé abrégé par UMI.

Thesis written in co-mentorship with director: Nelly Huynh; co-directors: Frank Rauch and Jean-Marc Retrouvey; collaborators: Clarice Nishio, Duy-Dat Vu and Nathalie Alos / Introduction - L'ostéogenèse imparfaite (OI) est une maladie osseuse héréditaire qui affecte la production du collagène de type I et le remodelage osseux. Les biphosphonates sont administrés aux enfants atteints d'OI dans le but d’augmenter la masse osseuse et de réduire les fractures osseuses. Les patients atteints d’OI ont des malocclusions sévères qui affectent leur qualité de vie. Plusieurs processus biologiques de remodelage osseux qui sont nécessaires pour un mouvement dentaire orthodontique sont affectés chez les gens atteints d’OI. L'objectif de cette étude est d'évaluer le mouvement dentaire orthodontique dans un modèle de souris avec OI et traitées aux biphosphonates. Matériels et méthodes - Vingt-quatre souris femelles âgées de 10 semaines ont été divisés en 4 groupes : 1 - OI traitées par zolédronate (n=6); 2 - OI non traitées (n=6); 3 - Type sauvage traitées par zolédronate (n=6); 4 – Type sauvage non traitées (n=6) Un ressort de nickel-titane activé à 10 g de force a été cimenté entre les incisives et la 1ère molaire maxillaire droite. Le côté contralatéral a été utilisé comme témoin. Une dose de 0,05 mg de zolédronate a été administrée par voie sous-cutanée un jour avant la chirurgie. Sept jours après l'intervention, les souris ont été euthanasiées et la distance entre la 1ère et la 2e molaire a été mesurée par analyse microtomographique. Résultats - Le mouvement dentaire orthodontique était significativement plus important chez les souris OI que celles de types sauvages dans les groupes non traités (p < 0,05). Le traitement par zolédronate n'a eu aucun effet significatif sur le mouvement dentaire orthodontique au sein des groupes OI et type sauvages. Conclusions - Ces résultats suggèrent une augmentation du mouvement dentaire orthodontique chez les souris avec l’ostéogenèse imparfaite. / INTRODUCTION - Osteogenesis imperfecta (OI) is a heritable bone disorder that affects collagen type I production and bone remodeling. Orthodontic tooth movement (OTM) involves the underlying process of alveolar bone remodeling. The objective of this study is to evaluate OTM in a mouse model of OI. METHODS - Twenty four, 10 week-old female mice were divided into 4 groups: 1- OI treated with zoledronate, 2- OI untreated, 3- Wild-type (WT) treated with zoledronate and 4- WT untreated. A nickel-titanium closed coil spring (10 g) was attached between the incisors and the right maxillary 1st molar. The contralateral side was used as control. Zoledronate (0.05mg/kg) was administered sub-cutaneously 1 day prior to surgery. Seven days after the procedure, the distance between 1st – 2nd molars was measured by micro-CT. RESULTS - OI mice presented significantly more OTM than WT mice when comparing within untreated groups (p<0.05). Zoledronate treatment had no significant effect on OTM within OI and WT groups. CONCLUSIONS - These results suggest increased OTM in mice with OI. The dose of zoledronate administrated 1 day prior to surgery had no significant effect on OTM.

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