As a result of ground water pumping in the Střeleč quarry there has been developed a depression in ground water surface during recent 30 years impacting an area of approx. 10 km2 . Due to the existence of steep hydraulic gradient in the quarry surroundings subsurface erosion occurs resulting in a development of underground channels. The biggest one developed in the years 2000 - 2002. Its length was 300 m reaching in some place the height of 17 m. During field works in the quarry in the years 2009 - 2010 the only accessible channel was mapped. In the channel two main types of cracks were discovered. On the crossing of these cracks slumping of the sandstone occurs which causes difficulties for the mining company. A hydraulic gradient higher than 5% was determined to be critical for sand transport in the channels and widening the initial conduits into channels. The channel development and releasing of static ground water reserves also influenced chemical composition of ground water emerging in the quarry. In the period of the most intensive channel development in 2001 the ratio of ground water from static reserves on the total amount pumped was 56%. Also in this period the concentration of sulphates in the ground water of the streams in the quarry decreased significantly. In the year 2010 there were...

Dans cette thèse, des méthodes de caractérisation acoustique passive et active de systèmes acoustiques à deux ports sont présentées, basées sur une décomposition d’ondes planes en entrée et sortie. Cette décomposition est réalisée par la méthode du beamforming. Ces méthodes mises en place et validées sur des géométries simples, sont ensuite employées pour caractériser l’étage compresseur d’un turbocompresseur de suralimentation automobile. La caractérisation acoustique active se fait par la mesure de la puissance et de l’intensité acoustique dans les conduits du compresseur, ceci pour des points de fonctionnement spécifiques, des cartographies compresseur complètes sont également élaborées. Les essais ont été menés sur banc turbo, banc moteur et sur véhicule complet. La caractérisation acoustique passive est abordée par le calcul de matrices du compresseur (matrice de transfert, matrice d’impédance et matrice de diffusion). Le calcul de la perte par transmission acoustique est déduit de ces matrices. Des essais ont été réalisés et comparés à des simulations éléments finis 3D sur un turbocompresseur statique comme sur un turbocompresseur opérationnel. / In this thesis, methodologies to perform the acoustic passive and active characterization of two port systems are presented. These methods are based on plane wave decomposition made at the inlet and at the outlet of the system. This decomposition is made according beamforming technique. Once these methods were validated on simple geometries, they were then applied to the compressor stage of an automotive turbocharger. The active acoustic characterization is made by the measurement of the acoustic power and acoustic intensity in the compressor ducts on given working points, but also on complete compressor maps. This was performed on turbocharger benches, engine benches and a complete vehicle. The passive acoustic characterization is made by the calculation of characteristic matrices (transfer matrix, impedance matrix and scattering matrix). These matrices are then used to compute the acoustic transmission loss. Experiments were performed on a static turbocharger and compared to 3D finite elements simulations, as well as experiments on an operating turbocharger.

Atualmente a otimização e redução de custos verificados na fabricação de tubulações está caminhando para um limite. Toda e qualquer modificação no processo produtivo exige grandes investimentos com retorno a prazos cada vez maiores. Assim, a possibilidade de poder contar com técnicas que permitam a redução de esforços sobre tubulações enterradas traz sem dúvida uma importante contribuição. Este trabalho estuda o uso da trincheira como forma de reduzir os esforços que atuam sobre condutos enterrados, utilizando duas séries de ensaios denominados \"A\" e \"B\". Cada série é composta basicamente de quatro combinações diferentes, com variações geométricas da relação de altura relativa (h/B) e largura relativa (b/B). A série B teve a posição relativa (H/B) da camada flexível modificada em relação à série A. Os ensaios realizados no Departamento de Geotecnia da Escola de Engenharia de São Carlos apresentam como resultado uma redução dos esforços da ordem de 44% a 86% em relação ao ensaio de referência montado sem o uso da camada indutora. / Nowadays the optimization and the reduction of costs verified in the pipes production are walking for a limit. All and whatever modification on the productive process demands great investments with larger time return. Thus, the possibility of taking account with techniques that allows reduction efforts on buried pipes bring without any doubt, an important contribution. This work studies the induced trench to reduce the efforts that act over buried conduits, using two series, \"A\" and \"B\", with four treatments each one. The A series is composed with four different combinations. These combinations have geometric variation between relative height (h/B) and relative width (b/B) of flexible layers, were built directly over the trap door. The \"B\" series is composed with the same geometric flexible layer used in series \"A\", and they have their relative position (H/B) modified. The treatments were conducted at the \"Departamento de Geotecnia\" da \"Escola de Engenharia de São Carlos\". The results obtained were a reduction of the 44 to 86% on the efforts in relation to the reference treatment built without the use of an induced layer.

Il est communément admis que les écoulements dans les aquifères karstiques sont particulièrement concentrés dans les conduits et les fractures principaux. Dans ce travail, on cherche à décrire le comportement du flux à différentes échelles. A l'échelle locale, on considère une modélisation des écoulements en milieu continu. A cela s'ajoute à l'échelle régionale l'inclusion de drains comme éléments discrets (approche hybride). Nous avons recours pour ceci à l'utilisation d'un modèle d'écoulement défini par des équations aux dérivées partielles qui décrivent l'écoulement dans un milieu à double-porosité. La solution analytique de ce modèle nous permet d'étudier les phases de transition des flux selon une condition à la limite de type charge imposée. Cela correspond à une perturbation hydraulique tel qu'un puits maintenu à charge constante. Afin d'inclure des conditions aux limites spécifiques (par exemple une limite imperméable) et une géométrie de domaine irrégulière, nous développons et employons un modèle numérique basée sur la méthode des éléments intégrales de frontière. Ceci permet de mettre en oeuvre l'approche hybride (milieu continu et discret) dans laquelle nous considérons les intersections entre conduits verticaux et horizontaux. Ce type de modélisation permet ainsi de considérer une échelle plus importante qu'un modèle continu seul.Par ailleurs, un modèle expérimental de laboratoire est conçu et réalisé afin d'étudier expérimentalement les phases de transition du flux issu de milieux hétérogènes. Cette approche est complémentaire de celle développée à l'aide de la solution analytique et du modèle numérique.Enfin, nous proposons le développement et les essais préliminaires d'un nouvel instrument de mesure. Il s'agit d'une sonde autonome qui a pour objectif de cartographier les conduits noyés dans les aquifères karstiques. Ainsi la géométrie des drains discrets pourra être représentée de façon plus réaliste dans le modèle numérique hybride.Les conclusions principales de ce travail sont les suivantes : à l'échelle locale et régionale, les phases de transition du flux dépendent des propriétés hydrauliques du milieu. La solution numérique permet d'étudier l'influence des géométries de domaine et de conditions aux limites complexes. Le modèle expérimental permet de reproduire qualitativement les phases de transition du flux analysées théoriquement. Enfin, la sonde permet de cartographier son parcours dans des conditions expérimentales contrôlées. Ces nouvelles méthodes contribuent à la caractérisation de l'hydrodynamique dans les aquifères karstiques. / Groundwater flow in karst aquifers is mainly concentrated into the principals hydraulic features such as conduits and fractures. This work is devoted to the description of the flow behavior at different scales. At the local scale, we model the groundwater flow with a continuum approach. At the regional scale however, we describe the groundwater flow by mean of a hybrid modeling approach that considers discret conduits and a multi continuum approach.We use in this work a groundwater flow model based on the double porosity approach. The analytical solution of this model allows to investigate the different flow transitions phases that are present when a constant head boundary condition is applied, for instance at a well.In order to include different boundary conditions as well as specific domain geometries, we apply in this work a boundary element method to solve the partial differential equations that describe our problem. This allows to further investigate the hybrid model (discret element and multi continuum) in which we consider discret intersections of vertical conduits with horizontal conduits. This modeling approach allows to consider a broader scale that the local scale to describe groundwater flow in karst aquifers.Asides, a physical experiment is developped in order to study experimentally the transition phases of the flow which comes from a heterogeneous reservoir. This approach is complementary to those developped with the analytical and the numerical studies. Finally, a new measuring instrument is developped and early field trials were carried out in this work. This new sensor is an autonomous underwater probe which aims to map unaccessible drowned karst conduits. With this tool, the geometry of the karst conduits will be more realisticly represented in the hybrid numerical model.The main conclusions of this work are the following : at the local and regional scales, the transition periods in the flux depend of the hydraulic properties of the reservoir. The numerical solution allow to study the influence of various complex domain geometries and boundary conditions. The physical experiment allows to reproduce qualitatively the transition periods in laboratory conditions. Finally, the autonomous sensor allows to map its path in controlled field conditions.These new approaches and methods contributes to the caracterisation of the hydrodynamical behavior of karst aquifers.

Vascularization of thick engineered tissue and organ constructs like the heart, liver, pancreas or kidney remains a major challenge in tissue engineering. Vascularization is needed to supply oxygen and nutrients and remove waste in living tissues and organs through a network that should possess high perfusion ability and significant mechanical strength and elasticity. In this thesis, we introduce a fabrication process to print vascular conduits directly, where conduits were reinforced with carbon nanotubes (CNTs) to enhance their mechanical properties and bioprintability. The generation of vascular conduit with a natural polymer hydrogel such as alginate needs to have improved mechanical properties in order to biomimic the natural vascular system. Carbon nanotube (CNT) is one of the best candidates for this goal because it is known as the strongest material and possesses a simple structure. In this thesis, multi-wall carbon nanotube (MWCNT) is dispersed homogenously in the hydrogel and fabricated through an extrusion-based system.In vitro evaluation of printed conduits encapsulated in human coronary artery smooth muscle cells was performed to characterize the effects of CNT reinforcement on the mechanical, perfusion and biological performance of the conduits. Perfusion and permeability, cell viability, extracellular matrix formation and tissue histology were assessed and discussed, and it was concluded that CNT-reinforced vascular conduits provided a foundation for mechanically appealing constructs where CNTs could be replaced with natural protein nanofibers for further integration of these conduits in large-scale tissue fabrication. It was concluded that MWCNT has a significant effect on mechanical properties, vascular conduit swelling ratio and biological characterization in short-term and long-term cellular viability.

Atualmente a otimização e redução de custos verificados na fabricação de tubulações está caminhando para um limite. Toda e qualquer modificação no processo produtivo exige grandes investimentos com retorno a prazos cada vez maiores. Assim, a possibilidade de poder contar com técnicas que permitam a redução de esforços sobre tubulações enterradas traz sem dúvida uma importante contribuição. Este trabalho estuda o uso da trincheira como forma de reduzir os esforços que atuam sobre condutos enterrados, utilizando duas séries de ensaios denominados \"A\" e \"B\". Cada série é composta basicamente de quatro combinações diferentes, com variações geométricas da relação de altura relativa (h/B) e largura relativa (b/B). A série B teve a posição relativa (H/B) da camada flexível modificada em relação à série A. Os ensaios realizados no Departamento de Geotecnia da Escola de Engenharia de São Carlos apresentam como resultado uma redução dos esforços da ordem de 44% a 86% em relação ao ensaio de referência montado sem o uso da camada indutora. / Nowadays the optimization and the reduction of costs verified in the pipes production are walking for a limit. All and whatever modification on the productive process demands great investments with larger time return. Thus, the possibility of taking account with techniques that allows reduction efforts on buried pipes bring without any doubt, an important contribution. This work studies the induced trench to reduce the efforts that act over buried conduits, using two series, \"A\" and \"B\", with four treatments each one. The A series is composed with four different combinations. These combinations have geometric variation between relative height (h/B) and relative width (b/B) of flexible layers, were built directly over the trap door. The \"B\" series is composed with the same geometric flexible layer used in series \"A\", and they have their relative position (H/B) modified. The treatments were conducted at the \"Departamento de Geotecnia\" da \"Escola de Engenharia de São Carlos\". The results obtained were a reduction of the 44 to 86% on the efforts in relation to the reference treatment built without the use of an induced layer.

Traumatic injuries resulting in peripheral nerve lesions often require a graft to bridge the gap. Although autologous nerve graft is still the first choice strategy in reconstructions, it has the severe disadvantage of the sacrifice of a functional nerve. Cell transplantation in a bioartificial conduit is an alternative strategy to create a favourable environment for nerve regeneration. Among adult stem cells, adipose-derived stem cells (ASC) are a useful tool in regenerative medicine as they can be induced towards multiple mesodermal and nonmesodermal lineages, being recently differentiated into cells showing Schwann cell-like morphology, glial cell markers and increased neurotrophic potential. The first two chapters of this work describe in vivo applications of Schwann cell-like differentiated ASC (dASC), seeded into biodegradable nerve guides made of fibrin, investigating both brief (2 weeks) and long (4 months) term effects on the regenerating nerves. Comparison was carried out with similarly differentiated bone marrow mesenchymal stem cells (dMSC), Schwann cells (SC)and empty fibrin conduits, as well as with autologous nerve grafts. Regeneration was evaluated in a 1cm gap total axotomy sciatic nerve injury model on rats. Results showed that dASC could improve regeneration distance in a similar manner to other regenerative cells inthe brief term. This effect was maintained and strengthened in the long term, where nerve morphology, spinal motoneurons regeneration, protection from muscle atrophy and electrophysiological performances of regenerated nerves were analysed. dASC positive effects lasted in the long term with functional results comparable to the autologous nerve grafts, which served as controls. The third chapter focuses on the possibility to further improve dASC regenerative performances using fibronectin and laminin, two key extracellular matrix (ECM) molecules involved in nerve regeneration, with the future aim to optimize cell host, directional cues and neurotrophism of tissue engineered conduits. Fibronectin and laminin protected dASC from stress-induced cell death in vitro, significantly increasing cell adhesion and viability. Laminin significantly improved neurotrophic properties of dASC enhancing neurite outgrowth of both primary sensory neurons and NG108-15 neurons co-cultured with dASC, suggesting a further activation of the neurotrophic effect of dASC by ECM molecules. These improved effects were increased when a direct contact was established between the laminin substrate, dASC and neurons, suggesting a primary role of laminin in contact signalling, finally boosting the neurotrophic potential of dASC. Further studies will be needed to clarify the interactions between dASC and the complexniche of peripheral nerve regeneration, including the ECM molecules. However, the neurotrophic potential of dASC expressed in both in vitro and in vivo experiments opens wide perspectives in tissue engineering applications among new methods to enhance peripheral nerve repair.

Large depression cone in water table was formed due to mining in surroundings of Střeleč quarry. The concentrated inflow from conduits to quarry is up to 70 l/s. Large conduit systems are created by flowing water into the quarry. The biggest conduit system was at least 300 m long and 17 m high with maximum calculated volume of 22 thousands m3 . Evolution of these conduits usually takes several months to few years. Fast conduit evolution allows to study erosion processes in detail in situ. In the thesis I am describing conduits, character of flow and erosion processes. Measured flow velocities in conduits are up to 0,4 m/s with hydraulic gradient 1 to 5%. Flow velocities and hydraulic gradients are typical for piping erosion. Piping initially forms small protoconduits. The bigger conduits are formed as water is progressively drained from larger area. Conduits are following fracture surfaces, which are also limiting the conduit propagation to the sides. Above water table the conduits are enlarged mainly by mass wasting of undercut sandstone slabs. For distinguishing less and more erodible parts of sandstone, we adapted and partially developed a method for measuring erodability (REI) and drilling resistance (DR). Both are used to compare different types of sandstone surfaces. In lowermost part of the...

Ce manuscrit porte sur le développement d’une méthode de calcul du bruit d’écoulement à faible nombre de Mach en conduite en présence d’obstacles. Elle consiste en une simulation numérique de l’écoulement dont les données sauvegardées servent dans un deuxième temps à l’estimation du rayonnement acoustique. Le calcul de mécanique des fluides est réalisé avec un modèle de turbulence LES incompressible. Un code a été développé pour le calcul acoustique qui comprend la transformée de Fourier des données de l’écoulement, le calcul par méthode intégrale et les post-traitements. L’originalité de la méthode réside dans le fait qu’elle nécessite comme informations sur l’écoulement uniquement des données surfaciques. Aucune donnée volumique n’a besoin d’être sauvegardée durant le calcul de mécanique des fluides. Dans une conduite obstruée par un obstacle, les principales sources de bruit se situent à proximité de l’obstacle et le rayonnement diffracté sur l’obstacle domine sur le rayonnement direct des sources. C’est la diffraction du rayonnement incident qui rend négligeable les données volumiques dans le calcul acoustique. Elle est étudiée et illustrée à travers le cas simplifié du rayonnement d’une source placée à proximité d’un obstacle en conduite. Des comparaisons calculs/essais favorables valident la méthode et le code de calcul développé. Plusieurs configurations sont étudiées : l’insertion dans un conduit rectangulaire droit d’un diaphragme, d’un agencement de deux diaphragmes et d’un volet. En présence d’un diaphragme, une théorie de la similitude est introduite ; en présence d’un double diaphragme, des phénomènes d’interaction entre les deux obstacles apparaissent et sont analysés ; et en présence d’un volet, des résonances particulières sont examinées. / This manuscript deals with the development of a calculation method of low Mach number flow noise in ducts in the presence of fixed obstacles. lt consists of a numerical simulation of the flow during which data are saved and used in a second time to estimate the acoustic radiation. The fluid calculation is performed with an incompressible LES turbulence model. A code has been developed for the acoustic computation which includes the Fourier transform of the flow data, the integral computation and the post-processing. The originality of the method lies in the fact that it requires as information on the flow only surface data. No volume term needs to be saved during the fluid calculation. ln a duct obstructed by an obstacle, the main sources of noise are located near the obstacle and the scattered field on the obstacle dominates on the direct radiation of the sources. lt is the diffraction of the incident radiation which makes the volume data negligible in the acoustic calculation. This is studied and illustrated through the simplified case of the radiation from a source located near a ducted obstacle. Favorable comparisons with measurements validate the method and the developed code. Several configurations are studied: the insertion into a straight rectangular duct of a diaphragm, an arrangement of two diaphragms and a flap. ln the presence of a diaphragm, a theory of similarity is introduced; in the presence of a double diaphragm, interaction phenomena between the two obstacles appear and are analyzed; and in the presence of a flap, particular resonances are examined.

La prédiction de la réduction passive du bruit nécessite l’utilisation de modèles d’impédance acoustique fiables. La proposition de tels modèles en présence d’écoulement est un problème qui reste ouvert. Les travaux réalisés dans cette thèse sont consacrés à la mise en place d’une méthode expérimentale et numérique permettant de tester la validité de modèles d’impédance acoustique de traitements SDOF en présence d’écoulement. Cette approche repose sur la comparaison de résultats expérimentaux issus d’un banc aéroacoustique, et de résultats numériques issus d’un modèle FEM-PML axisymétrique basé sur l’équation de Galbrun. Ainsi, dans la première partie de cette thèse, le modèle FEM-PML utilisé est présenté. Dans la seconde partie, des modèles d’impédance acoustique de SDOF tenant compte de l’écoulement sont exposés, ainsi que la méthode de validation de ces modèles et les résultats de ces validations. / Prediction of noise reduction requires reliable acoustic impedance models. The proposal of such models in the presence of a mean flow is a problem which remains open. This thesis is devoted to the development of an experimental and a numerical method to test the validity of SDOF treatments acoustic impedance models in the presence of mean flow. This approach is based on the comparison of experimental results from an aeroacoustical duct, and numerical results from a FEM-PML axisymmetric model based on Galbrun’s equation. Thus, in the first part of this thesis, the FEM-PML model is presented. In the second part, some acoustic impedance models are exposed, and the validation method and the results of these validations are presented.