As cinzas de carvão são subprodutos da combustão de carvão mineral gerados em grandes quantidades a partir de usinas termelétricas no mundo todo. Nos últimos anos, pesquisas sobre a utilização das cinzas estão sendo desenvolvidas visando soluções sustentáveis, garantindo, assim, a preservação do meio ambiente e a saúde humana. As cinzas de carvão podem ser aproveitadas como matéria-prima para síntese de zeólita, material este que possui uma vasta gama de aplicações industriais. Em muitas dessas aplicações é requerido o uso de formas peletizadas de zeólitas. Nesse contexto, o objetivo do presente estudo foi desenvolver um método de obtenção de zeólita de cinzas leves de carvão na forma granular e avaliar seu uso como material adsorvente. A primeira etapa deste estudo consistiu na síntese e caracterização de zeólita convencional (ZCL) e de zeólita do tipo NaA com alto grau de pureza (ZA). As cinzas leves de carvão utilizadas na síntese das zeólitas foram coletadas na Usina Termelétrica Jorge Lacerda, localizada no Estado de Santa Catarina, Brasil, o maior complexo termelétrico a carvão da América Latina. O material de partida e as zeólitas sintetizadas em pó foram caracterizados em termos da composição química, composição mineralógica, morfologia, capacidade de troca catiônica, estabilidade térmica, área superficial específica, distribuição de poros e dos grupos funcionais. As fases zeolíticas formadas por tratamento hidrotérmico foram hidroxisodalita e traços de NaX. A zeólita do tipo NaA foi sintetizada por método de duas etapas apresentando grau de pureza de 84%. O valor de capacidade de troca catiônica da zeólita A com alto grau de pureza foi aproximadamente duas vezes maior do que o valor encontrado para a zeólita convencional (1,84 meq g-1 para ZCL e 3,81 meq g-1 para ZA). Na segunda etapa, os produtos zeolíticos sintetizados neste estudo foram peletizados com a aplicação de diferentes métodos. Os grânulos de zeólitas foram formados manualmente na forma de esferas na faixa de tamanho entre 3 mm e 7 mm a partir da mistura das zeólitas em pó com um ou mais agentes aglutinantes e adição de água deionizada. As diferentes metodologias experimentais de peletização das zeólitas sintetizadas foram comparadas e avaliadas por meio da determinação da capacidade de troca catiônica dos produtos obtidos, trabalhabilidade, resistência mecânica e estabilidade em água. O método de peletização no qual as argilas caulinita e bentonita foram usadas como agentes aglutinantes, na proporção de 5% em massa cada, foi considerado o melhor para a zeólita convencional. Para a zeólita A, foi selecionado o método com 10% de bentonita. Os valores de capacidade de troca catiônica dos produtos zeolíticos foram mantidos após o processo de peletização. Posteriormente foi realizado um estudo direcionado à aplicação da zeólita granular no tratamento de água. A amostra de zeólita A com alto grau de pureza peletizada, obtida pelo método otimizado, foi selecionada para ser usada como material adsorvente no processo de adsorção de íons cádmio em solução aquosa em coluna de leito fixo. Os resultados evidenciaram a potencialidade do uso da zeólita A peletizada no tratamento de efluentes. / Coal ashes are by-products of coal combustion generated in large quantities from thermoelectric plants worldwide. In recent years, research on the use of ash has been developed aiming at sustainable solutions, thus guaranteeing the preservation of the environment and human health. Coal ashes can be used as raw material for zeolite synthesis, which has a wide range of industrial applications. In many such applications the use of zeolite pelletized forms is required. In this context, the objective of the present study was to develop a method to obtain zeolite of light ash from coal in the granular form and to evaluate its use as an adsorbent material. The first step of this study was the synthesis and characterization of zeolite conventional (ZFA) and of the zeolite NaA type with a high degree of purity (ZA). The coal fly ashes used in the synthesis of the zeolites were collected in the Thermoelectric Complex Jorge Lacerda, located in the Santa Catarina State, Brazil, the largest coal burning thermoelectric complex of Latin America. The starting material and the zeolites synthesized in powder were characterized in terms of chemical composition, mineralogical composition, morphology, cation exchange capacity, thermal stability, specific surface area, pore distribution and functional groups. The zeolitic phases formed by conventional hydrothermal treatment were hydroxysodalite and traces of NaX. The zeolite of the NaA type was synthesized by a two-step method with a fusion step having a degree of purity of 84%. The value of cation exchange capacity of zeolite A with high purity was approximately two times higher than the value found for the zeolite conventional (1.84 meq g-1 for ZFA and 3.81 meq g-1 for ZA). In the second step, the zeolitic products synthesized in this study were pelletized with the application of different methods. The zeolite granules were formed manually in the form of spheres in the size range between 3 mm and 7 mm from the powder mixture of zeolite with one or more binders and addition of deionized water. The different experimental methodologies of pelletization the synthesized zeolites were compared and evaluated through of the determination of the cation exchange capacity, workability, mechanical strength and water stability. The pelletization method in which clays kaolinite and bentonite were used as binders in the proportion of 5% by weight each was considered the best for the conventional zeolite. For zeolite-A, was selected the method with 10% bentonite. The cation exchange capacity values of the zeolitic products were maintained after the pelletization process. Subsequently, a study was carried out on the application of granular zeolite in water treatment. The zeolite-A sample with high degree of pelletized purity, obtained by the optimized method, was selected to be used as adsorbent material in the adsorption process of cadmium ions in aqueous solution in a fixed bed column. The results evidenced the potential of the use of pelletized zeolite-A in the treatment of effluents.

Dans cette thèse, nous présentons une méthode de segmentation d’images radiographiques des membres inférieurs en régions d’intérêt (ROIs), une méthode de recalage rigide tridimensionnel (3D) / bidimensionnel (2D) des prothèses du genou sur les deux images biplanaires radiographiques calibrées et une méthode de reconstruction 3D des membres inférieurs à partir de deux images biplanaires radiographiques calibrées. Le premier article présente une méthode de segmentation de rotule, astragale et bassin des images radiographiques en régions d’intérêt basée sur la fusion de multi-atlas et superpixels. Cette méthode utilise l’apprentissage d’une base de données d’images radiographiques de ces os segmentées manuellement et recalées entre elles pour estimer un ensemble de superpixels permettant de tenir compte de toute la variabilité locale et non linéaire existante dans la base, puis la propagation d’étiquettes basée sur le concept d’entropie pour raffiner la carte de segmentations en régions internes afin d’obtenir le résultat final. Le deuxième article présente une méthode de recalage rigide 3D / 2D des composants tibiaux et fémoraux de prothèse du genou sur deux images biplanaires radiographiques calibrées. Cette méthode utilise une mesure de similarité hybride basée sur les notions de contours et régions puis un algorithme d’optimisation stochastique pour estimer la position des composants. La similarité basée sur les régions est stable et robuste contre les bruits. Cependant, cette mesure n’est pas précise car le nombre de pixels aux contours est inférieur au celui à l’intérieur de la région. Au contraire, la similarité basée sur les contours est précise mais plus sensible au bruit ou à d’autres artefacts existant dans les images. C’est pourquoi la combinaison de ces deux similarités fournit une méthode de recalage robuste et précise. Le troisième article représente une méthode statistique biplanaire de reconstruction 3D de rotule, astragale et bassin. Cette méthode utilise un algorithme de réduction de dimensionnalité pour définir un modèle déformable paramétrique qui contient toutes les déformations statistiques admissibles apprises à partir d’une base de données des structures osseuses. Puis un algorithme d’optimisation stochastique est utilisé pour minimiser la différence entre la projection des contours / régions des modèles surfaciques osseux avec ceux segmentés sur les deux images radiographiques. / In this thesis, we present a segmentation method of lower limbs of X-ray images into regions of interest (ROIs), a three-dimensional (3D) / two-dimensional (2D) rigid registration method of knee implant components to biplanar X-ray images, and a 3D reconstruction method of the lower limbs using biplanar X-ray images. The first paper presents a superpixel and multi-atlas-based segmentation method of the patella, talus, and pelvis into regions of interest. This method uses a training dataset of pre-segmented and co-registered X-ray images of these bones to estimate a collection of superpixels allowing to take into account all the nonlinear and local variability existing in the dataset, then a propagation of label based on the entropy concept for refining the segmentation map into internal regions to the final result. The second paper presents a 3D / 2D rigid registration method of tibial and femoral components of knee implants to calibrated biplanar X-ray images. This method uses a hybrid edge- and region-based similarity measure then a stochastic optimization algorithm to estimate the component position. The region-based similarity is stable and robust to noise. However, this measure is not precise because the number of pixels in the border is fewer than the number of pixels inside the region. On the contrary, the edge-based similarity is accurate but more sensitive to noise or other artifacts existing in the images. That’s why the combination of these two similarity types provides a robust and accurate registration method. The third paper presents a statistical biplanar 3D reconstruction method of the patella, talus, and pelvis. This method uses a dimensionality reduction algorithm to define a deformable parametric model which contains all admissible statistical deformations learned from the bone structure dataset. Then a stochastic optimization algorithm is used to minimize the difference between the contour / region projection of bone models and the contours / regions in two segmented X-ray images.