The energy produced by the flow of water is known as hydropower. It is an easily accessible and available source of energy in large quantity in the form of, rivers, lakes, streams and runoffs around the world. Hydropower is dependent upon hydrological cycle hence; this beneficial characteristic of hydropower makes it a renewable source of energy. Hydropower is free from poisonous emission; therefore, it is considered as a safer and pollution free source of energy. It is usually used to develop electricity from generators. These generators are connected to the hydro turbines by means of shaft. The electricity produced from hydropower is stable and steady because of its higher capacity, thus it can be a suitable source to work as base-load and used to balance the power fluctuations caused by varying loads. The hydropower can also be accommodated with different sources such as solar and wind system. This way of power sharing needs quick regulation as the deviation in the power grid changes rapidly. To fulfil this power demand with higher stability prompted to the development of modern turbines with more efficient, reliable and robust design.   To achieve the above target, it is of prime importance to improve efficiency of hydro turbine. Nevertheless, many methods are in practice for improvement for efficiency of the turbine; though one of the prime elements which influence the turbine efficiency is surface roughness. The effect of surface roughness differs for different turbine components like stay vanes, guide vanes, runner, draft tube and spiral casing.   The main purpose of this thesis is to examine the effect of surface roughness for hydro turbine step-up efficiency. It is based on reduced scale model to prototype conversion method. For this purpose, IEC_62097 has provided an excel sheet as an attachment for calculation. There has been always a need to perform model test, since performing test on the prototype itself is very accurate, and calculations too, do not yield reliable results. Therefore, the model to prototype conversion method is considered a better solution.   A sensitivity analysis is conducted on a Kaplan turbine situated at the Granfors power station located along the Skellefteå river about 30 km from the city of Skellefteå. The results obtained after applying the latest step-up expressions are described and presented. These outcomes have shown significant positive impact on the hydro turbine efficiency improvement, which are presented in graphs.   The most significant variations of step-up efficiency against surface roughness were observed in the runner part of the turbine. This specific characteristic makes it evident that more focus and test should be conducted on this part to improve efficiency.

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Expanding the standard, single-well recording geometry used to monitor seismicity during hydro-fracture treatments could provide more accurate hypocenter locations and seismic velocities, improving general reservoir characterization. However, for the real, two-well data set obtained for this project, only S-wave picks were available, and testing resulted in anomalous hypocenter location behavior. This study uses a hypocenter location algorithm and both real and synthetic data sets to investigate how the accuracy of the velocity model, starting hypocenter location, recording geometry, and arrival-time picking error affect final hypocenter locations. Hypocenter locations improved using a velocity model that closely matched the observed sonic log rather than a smoothed version of this model. The starting hypocenter location did not affect the final location solution if both starting and final locations were between the wells. Two solutions were possible when the true solution was not directly between the wells. Adding realistic random picking errors to synthetic data closely modeled the dispersed hypocenter error pattern observed in the real data results. Adding data from a third well to synthetic tests dramatically reduced location error and removed horizontal geometric bias observed in the two-well case. Seismic event data recorded during hydro-fracture treatments could potentially be used for three-dimensional joint hypocenter-velocity tomography. This would require observation wells close enough to earthquakes to record P- and S-wave arrivals or wells at orientations sufficient to properly triangulate hypocenter locations. Simulating results with synthetic tests before drilling could optimize survey design to collect data more effectively and make analysis more useful. / Master of Science

Smart sensors have become and will continue to constitute an enabling technology to wirelessly connect platforms and systems and enable improved and autonomous performance. Automobiles have about two hundred sensors. Airplanes have about eight thousand sensors. With technology advancements in autonomous vehicles or fly-by-wireless, the numbers of these sensors is expected to increase significantly. The need to conserve water and energy has led to the development of advanced metering infrastructure (AMI) as a concept to support smart energy and water grid systems that would respond to emergency shut-offs or electric blackouts. Through the Internet of things (IoT) smart sensors and other network devices will be connected to enable exchange and control procedure toward reducing the operational cost and improving the efficiency of residential and commercial buildings in terms of their function or energy and water use. Powering these smart sensors with batteries or wires poses great challenges in terms of replacing the batteries and connecting the wires especially in remote and difficult-to-reach locations. Harvesting free ambient energy provides a solution to develop self-powered smart sensors that can support different platforms and systems and integrate their functionality. In this dissertation, we develop and experimentally assess the performance of harvesters that draw their energy from air or water flows. These harvesters include centimeter-scale micro wind turbines, piezo aeroelastic harvesters, and micro hydro generators. The performance of these different harvesters is determined by their capability to support wireless sensing and transmission, the level of generated power, and power density. We also develop and demonstrate the capability of multifunctional systems that can harvest energy to replenish a battery and use the harvested energy to sense speed, flow rate or temperature, and to transmit the data wirelessly to a remote location. / PHD

This thesis demonstrates that geological setting, depositional facies, open system flux of hot basinal brines and descending of shallow waters have a strong impact on the distribution of the diagenetic alterations within continental and paralic/shallow marine sandstones which in turn control the quality and heterogeneities of the reservoirs. Geological setting controls the mineralogical and textural maturity of sandstone, whereas depositional facies control the pore water chemistry (marine, brackish or meteoric), sedimentary texture and sand body geometry. Eogenetic alterations in the fluvial deposits are dominated by precipitation of infiltrated clays, kaolinitization of detrital silicates, whereas the shallow marine deposits are dominated by precipitation of early calcite and kaolinite. Conversely mesogenetic alterations are dominated by clay minerals transformation, quartz overgrowths and Ferroan- carbonates, barite and anhydrite. Flux of hot basinal brines is evidenced by precipitation of mesogenetic minerals that lack of internal sources (e.g. barite, anhydrite and ferroan carbonate cements), which is evidenced by: (1) restricted occurrence of these minerals in downthrown blocks. (2) The high fluid inclusion homogenization temperatures (Th) of quartz overgrowths (Th &gt; 110-139°C), and carbonate cements (T &gt; 80-140°C), which also have light δ18OV-PDB(-17.6‰ to -6.7‰). Flux of hot basinal brines is further evidenced by occurrence of saddle Fe-dolomite along stylolites. Fluid inclusion microthermometry further revealed a dramatic shift in pore- water chemistry from NaCl dominated brines during precipitation of quartz overgrowths to NaCl-CaCl2 dominated brines during cementation by Fe-dolomite. Presence of mixed brine (NaCl+CaCl2) systems in the fluid inclusions suggests flux of descending waters, which have circulated in the overlying carbonate-evaporite successions. The restricted occurrence of oil- filled inclusion to quartz overgrowths and methane to Fe-carbonate cements suggest migration of oil during precipitation by quartz and migration of methane during precipitation by Fe- carbonate cements. The extensive mesogenetic cements in the down thrown blocks is attributed to flux of basinal brines along deep seated faults, i.e. open system diagenesis. Integration of fluid inclusion microthermometry, isotopes, Raman spectrometry and thermal tectonic evolution of basins are essential techniques for unraveling the evolution of basinal fluids, cementation conditions and relative timing of hydrocarbons migration. / <p>Errata: Felaktigt disputationsdatum på spikbladet.</p>

La présente étude vise à comprendre le comportement chimico-hydro-mécanique des argiles raides à travers deux formations géologiques, l'argile de Boom et les argiles yprésiennes, qui sont censées être des formations hôtes potentielles pour le stockage de déchets radioactifs en Belgique. Le comportement volumique a été étudié tant à l'état intact qu'à l'état reconstitué, et sous différentes conditions : K0 et isotrope, sous des boucles de chargement - déchargement. Les résultats obtenus montrent que le comportement volumique de ces argiles est gouverné par la compétition entre l'effet physico-chimique et l'effet mécanique, caractérisée par une contrainte seuil qui correspond à la contrainte de gonflement en termes de changements de structure. Une loi de comportement volumique a été ainsi développée afin de décrire cet aspect. La perméabilité a été déterminée, comparée avec les résultats dans la littérature et corrélée avec les paramètres comme l'indice des vides. La variation de la perméabilité avec la profondeur ont mis en évidence le rôle déterminant des macro-pores dans le transfert des fluides. Le comportement volumique et la perméabilité des argiles de Boom et yprésiennes intactes sont aussi influencés par la variation de la composition chimique de l'eau de pore, qui modifie la double couche diffuse et favorise l'agrégation des particules argileuses. Les caractéristiques élastiques, la surface de charge et l'enveloppe de rupture ont été identifiées pour le comportement déviatorique des argiles de Boom et yprésiennes. Un modèle élasto-plastique conceptuel a été développé permettant de tenir compte des effets du gonflement et de la compétition entre l'effet mécanique et l'effet physico-chimique

The wave energy converter developed at Uppsala University consists of a linear generator at the seabed driven by the motion of a buoy on the water surface. The energy absorbed by the generator is negatively affected by variations of the mean sea level caused by tides, changes in barometric pressure, strong winds, and storm surges. The work presented in this doctoral thesis aims to investigate the losses in energy absorption for the present generation wave energy converter due to the effect of sea level variations, mainly caused by tides. This goal is achieved through the modeling of the interaction between the waves and the point absorber. An estimation of the economic cost that these losses imply is also made. Moreover, solutions on how to reduce the negative effect of sea level variations are discussed. To this end, two compensation systems which adjust the length of the connection line between the floater and the generator are designed, and the first prototype is built and tested near the Lysekil research site. The theoretical study assesses the energy loss at about 400 coastal points all over the world and for one generator design. The results highlight critical locations where the need for a compensation system appears compelling. The same hydro-mechanic model is applied to a specific site, the Wave Hub on the west coast of Cornwall, United Kingdom, where the energy loss is calculated to be about 53 %. The experimental work led to the construction of a buoy equipped with a screw jack together with its control, measurement and communication systems. The prototype, suitable for sea level variations of small range, is tested and its performance evaluated. A second prototype, suitable for high range variations, is also designed and is currently under construction. One main conclusion is that including the compensation systems in the design of the wave energy converter will increase the competitiveness of the technology from an economic point of view by decreasing its cost per kWh. The need for a cost-effective wave energy converter with increased survivability emphasizes the importance of the presented research and its future development.

La présente étude concerne le comportement hydromécanique des matériaux compactés à base de bentonite pour le stockage des déchets radioactifs en grande profondeur. Trois matériaux candidats ont été étudiés : la bentonite (MX80) pure, le mélange bentonite/argilite broyée et le mélange bentonite/sable. Une étude expérimentale sur la pression de gonflement du mélange bentonite/argilite a été premièrement réalisée. Cette étude a mis en évidence l'effet de la salinité de l'eau, de la procédure et la durée d'hydratation, du pré-existant vide technologique et des méthodes expérimentales. Une importante relation entre la pression de gonflement et la densité sèche finale de la bentonite a été élaborée. Ensuite, des essais de rétention d'eau, des essais d'hydratation et des essais oedométriques à succion contrôlée ont été réalisés sur des échantillons à différentes porosités tout en considérant la présence du vide technologique. En introduisant les paramètres comme indice des vides de la bentonite et le ratio volume d'eau, une analyse globale des effets des vides sur la réponse hydromécanique de la barrière ouvragée a été effectuée. Pour obtenir un meilleur aperçu de l'évolution de l'étanchéité dans le cas de vide technologique, l'effet de densité sèche finale (densité après fermeture de vide technologique) et du temps d'hydratation sur la microstructure a été, de même, étudié. La perméabilité de ce matériau à l'état non saturé a été ensuite étudiée en réalisant des essais de rétention d'eau et d'infiltration ainsi que par des observations de la microstructure. Les résultats obtenus ont permis de relier la variation de la conductivité hydraulique non saturée aux changements de la microstructure. Une expérimentation en modèle réduit reproduisant à une échelle 1/10ème les essais in-situ (SEALEX) a été effectuée, et cela pour étudier la reprise des vides à long terme d'un mélange compacté bentonite/sable, tout en considérant la présence d'un vide technologique. Les résultats ont été utilisés pour interpréter les observations de l'essai in situ. A une échelle de temps réduite, cette étude fournit des informations utiles pour estimer la durée et l'efficacité de la conception en place. Finalement, les données expérimentales obtenues dans le laboratoire sur le mélange bentonite/sable ont été interprétées dans le cadre du modèle de Barcelone (BExM). Après comparaison des résultats expérimentaux avec le modèle, les performances et les limitations du modèle ont été analysées / This study deals with the hydro-mechanical behaviour of compacted bentonite-based materials used as sealing materials in high-level radioactive waste repositories. The pure MX80 bentontie, mixtures of MX80/crushed claystone and MX80/sand were used in the investigation. An experimental study on the swelling pressure of the bentonite-based materials was first performed. The results evidenced the effects of water chemistry, hydration procedure and duration, pre-existing technological void and experimental methods. Emphasis was put on the relationship between the swelling pressure and the final dry density of bentonite. Afterwards, the water retention test, hydration test and suction controlled oedometer test were conducted on samples with different voids including the technological void and the void inside the soil. By introducing the parameters as bentonite void ratio and water volume ratio, an overall analysis of the effects of voids on the hydro-mechanical response of the compacted material was performed. To get better insight into the seal evolution in case of technological void, the effects of final dry density and hydration time on the microstructure features were also characterized. Then, the hydraulic properties under unsaturated state were investigated by carrying out water retention test and infiltration test as well as the microstructure observation. The results obtained allowed relating the variation of hydraulic conductivity to the microstructure changes. A small scale (1/10) mock up test of the SEALEX in situ experiment was also performed to study the recovery capacity of bentonite-based material with consideration of a technological void. The results were used for interpreting the in-situ observations. With a reduced time scale, it provides useful information for estimating the saturation duration and sealing effectiveness of the field design. Finally, the experimental data obtained in the laboratory on bentonite/sand mixture were interpreted in the framework of the Barcelona Expansive Model (BExM). By comparing the model with the experimental results, the performance and limitation of the model were analyzed

La pierre monumentale subit au fil du temps des mécanismes de dégradation physiques, chimiques et biologiques qui détruisent l’épiderme des monuments et affectent la structure porteuse et sa stabilité. La compréhension des mécanismes de dégradation est nécessaire pour les gestionnaires d’ouvrages surtout que les études menées jusqu’à présent sont souvent incomplètes. Dans cette problématique, une étude de la dégradation de la pierre calcaire de Blaye est réalisée en collaboration avec le projet européen Medachs et la mairie de Blaye. Cette étude est composée de deux parties principales réalisées sur le site et en laboratoire. L’étude in-situ consiste à appareiller une pierre de façon à avoir la température de l’air et à la surface, à l’extérieur et à l’intérieur du bâtiment, et à 3 profondeurs dans la pierre. Un modèle numérique alimentée par les résultats des mesures expérimentales est élaboré pour estimer la valeur de la conductivité thermique du matériau. La pierre est alors découpée en 3 épaisseurs et la conductivité thermique est calculée pour chaque épaisseur en appliquant une méthode d’optimisation (Powell). La variation de la conductivité est directement liée à celle de la porosité et donc de l’état d’altération du matériau. L’étude au laboratoire est réalisée en deux étapes. En premier temps, des éprouvettes du matériau vierge en provenance de la carrière locale sont utilisées pour caractériser l’état initial du matériau. Pour cela, des paramètres physiques (masse volumique, porosités) et des paramètres mécaniques (vitesse ultrasonore et résistance mécanique) sont mesurés et identifiés. En deuxième temps ,nous réalisons des essais de vieillissement accéléré par action des sels et par action des cycles hygrothermiques. Les essais montrent la fragilité du matériau et mettent en évidence une résistance très faible face à la cristallisation de sels. Le travail réalisé, à la fois en laboratoire et in-situ, met en évidence la nécessité de mieux comprendre les mécanismes de dégradation et de mieux connaitre le matériau en particulier au niveau de l’action des sels. On propose de réaliser des essais qui prennent plus en compte les conditions d’exposition de la pierre (température, nature des sels, etc.). / Monumental stone is exposed to alteration caused by physical, chemical and biological mechanisms of degradation. With time, these mechanisms can destruct the monument epidermis and endanger the structure stability. The complex mechanisms of stone degradation are not fully understood. Our scientific knowledge is incomplete. Within the framework of the maintenance of historical monuments, a study of Blaye limestone alteration is realized with the collaboration of the European project Medachs and the town hall of Blaye. Our study can be divided into two major parts : an in-situ study and a laboratory study. The on site study consists on measuring the temperature evolution at the internal and external surface of a chosen stone in the building as well as the temperature evolution at the air in the inside and the outside of the building and at three depths in the stone. A numerical model is built in order to estimate the thermal conductivity of the stone based on the measurements results. The model consists on considering that the stone is composed of three layers characterized with three different values of the thermal conductivity. These values are estimated by using an optimization algorithm (Powell). The thermal conductivity varies with the porosity and thus can be considered as an indicator of the stone damage On the other hand, the laboratory study is realized in two stages. At first, the physical and the mechanical parameters of the original material are estimated by carrying out different measurements (relative density, porosiy, ultrasonic velocity, and compressive resistance). The samples that were used for the measurements were extracted from the local quarry. Then two types of accelerated ageing tests were realized : salt crystallization and hydro-thermal cycles. The results of the tests showed a low resistance of the material especially to salt crystallization. At the end, the results of the in-situ and the laboratory study show the fragility of the material and highlight the need and the importance of a better understanding of the degradation mechanisms. The effect of the environmental conditions should be included in the studies in order to have a clear image about the variation of the material resistance to salt crystallization with the exposure conditions (temperature, type of salts, etc.).