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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Hydraulic properties of the Table Mountain Group (TMG) aquifers

Lin, Lixiang January 2008 (has links)
Philosophiae Doctor - PhD / Research findings in current study provide a new insight into the fractured rock aquifers in the TMG area. Some of the results will have wide implications on the groundwater management and forms a solid basis the further study of the TMG aquifers.
172

Mise en évidence et simulation de l’endommagement des revêtements de carbone amorphe pour application moteur à combustion interne / DLC damage identification and simulation for internal combustion engine application

Pagnoux, Geoffrey 23 September 2015 (has links)
L'exploitation de revêtements micrométriques à base de carbone amorphe (les DLC) tend à se généraliser au sein des constructeurs automobiles afin d'améliorer le rendement des moteurs à combustion interne en réduisant les pertes mécaniques par frottement. Si ces revêtements exhibent généralement d'excellentes propriétés tribologiques et de très faibles taux d'usure, leur utilisation au sein des moteurs à combustion interne révèle que, soumis à des sollicitations complexes, de nombreux modes de dégradations sont observables. La propagation prématurée de ces dégradations sur l'intégralité des surfaces revêtues constitue un risque à maîtriser pour garantir la fonction des revêtements dans le temps. Cette maîtrise implique d'une part de connaître et de comprendre les mécanismes de dégradations probables des DLC appliqués aux composants du moteur et d'autre part de disposer d'outils de simulation de leur durée de vie, exploitables pour optimiser les systèmes tribologiques au plus tôt de leur conception. Les travaux présentés dans cette thèse ont été guidés par ces objectifs et rassemblent des expertises de composants revêtus, des développements d'analyses numériques, de protocoles d'essais simplifiés et des recherches de couplages entre modes de dégradations. Autant d'éléments qui permettent de répondre en partie aux questions initialement posées et de proposer, au final, un outil de simulation de durée de vie des DLC adapté aux applications moteur à combustion interne / The use of micrometric diamond-like carbon coatings (named DLC) are becoming widely used by automotive manufacturers in order to improve the efficiency of internal combustion engines by reducing the mechanical friction losses. Although DLC coatings generally exhibit excellent tribological properties and very low wear rates, their use in internal combustion engines shows that, subject to complex loadings, many degradation modes are observable. Untimely propagation of these latter upon the entire coated surfaces is a risk to control in order to guarantee the coating function over time. From one hand, this control implies to know and to understand all DLC degradation mechanisms when applied to engine components. On the other hand, it is necessary to possess lifetime simulation tools that can be used to optimize tribological systems in their early design. The work presented in this thesis has been guided by these goals and gathers experimental analyses of DLC-coated components, numerical analyzes, simplified testing protocols and coupling analyses of degradation processes. All these topics finally lead to the definition of a lifetime simulation tool adapted to DLC coated internal combustion engine applications
173

FEM model ultrazvukového senzoru hladiny oleje / Numerical model of ultrasonic oil level sensor

Chutný, Pavel January 2017 (has links)
This master’s thesis verifies physical principle of ultrasound in fluids by numerical model. At first, ultrasound study is ment. In second theoretic part, diferent kind of motor oils are described. Next, equations for numerical simulation are presented. In practical part, numerical model of level sensor is examined in well-knowed fluids (water, air). Results of laboratory measurement on topic of ultrasound velocity in oil dependent on temperature are aplicated on numerical model of sensor and optimalized.
174

Hydrodynamický model soutokové oblasti Svitavy a Svratky / Hydrodynamic model in the area of the confluence of the rivers Svitava and Svratka

Halaška, Ondřej January 2018 (has links)
Master's thesis deals with present state assessment of flood hazard on rivers Svitava and Svratka in the southern part of Brno. Flood discharges Q5, Q20, Q100 and Q100N were solved using coupled 1D/2D numerical model. All results were evaluated as maps of hazard.
175

Numerické modelování proudění v bezpečnostním přelivu / Numerical modeling of flow in spilway

Svoboda, Jiří Unknown Date (has links)
The goal of the diploma thesis is the numerical modelling of flow in planned spillway of the Boskovice dam. In the introduction of this diploma thesis are described and divided basic spillways according to their types and profiles. There are also mentioned emergency spillways. Then the thesis introduces the description of calculation of overflow quantity, the description of mathematic modelling and used turbulent models. The next part is concerned with the technical description of the Boskovice dam, the creation of virtual 3D model of spillway and spillway chute in the AutoCAD 2020 software and concerned with the control and revision of model in the Blender software. In the end of the thesis are mentioned results of numeric modelling of flow gained from the Flow-3D software and the comparison of results with the research of hydraulic model implemented at Water structures institute of Faculty of Civil Engineering of BUT.
176

Optimalizace výfukového potrubí přeplňovaného zážehového motoru / Optimalization of Exhaust Manifold for SI Turbo Engine

Andrys, Michal January 2010 (has links)
Abstract Michal ANDRYS Optimalization of Exhaust Manifold for SI Turbo Engine DP, IAE, 2010, 67 pp., 75 fig. The Diploma thesis is oriented on the design of exhaust manifold for si turbo engine. It specifies suitable manifold connection to the separate branches, folowed by CFD analysis.
177

Studie protipovodňových opatření v lokalitách Husovice a Židenice na Svitavě v km 6,000 – 9,000 / Feasibility study of the flood protection measures in the localities of Husovice and Židenice at the Svitava river at km 6,000 – 9,000

Hanzlíková, Zuzana January 2016 (has links)
Diploma thesis deals with a suggestion of flood protection measures on the Svitava river in km 6,000 – 9,000. Solved locality is found in Brno, particularly in city parts of Husovice and Židenice. Thanks to used joined 1D and 2D model were made hydraulic calculations for peak water stages Q1, Q5, Q20 a Q100. The outputs of hydraulic calculations were used afterwards for creation of maps of flood danger and drawing documentation of flood protection measures.
178

Hodnocení kontaminace podzemních vod v oblasti Letiště Přerov / Assessment of ground water contanination at the Přerov airport

Petrula, Lubomír January 2017 (has links)
The main goal of this work is to assess ground water contamination at the Přerov airport as a consequence to oil products leakage. For this purpose a flow and transport model was created. Another goal is to create and assess several variations of unfavorable scenarios in terms of water quality. The final goal is to create a set of recommendations for the entire area.
179

Studie protipovodňových opatření v lokalitách Pisárky a Staré Brno na Svratce / Feasibility study of the flood protection measures in the localities of Pisárky and Staré Brno at the Svratka rive

Charvát, Jan January 2017 (has links)
This thesis deals with the assessment of the current state of flood protection in Brno, Pisárky and the Staré Brno district on the Svratka river at km 37.053 to 41.116 and the subsequent design and assessment of flood protection measures. Hydraulic calculations were carried out using the coupled 1D / 2D numerical model of water flow to pass peak flows Q1, Q5, Q20, Q100 a Q100 unaffected. The results are processed in the form of inundation maps and drawing documentation.
180

Étude hydrogéologique de l’aquifère transfrontalier Milk River (Canada-USA) : modèles géologique, conceptuel et numérique pour la gestion raisonnée de la ressource / Hydrogeological study of the Milk River Transboundary Aquifer (Canada-USA) : Geological, conceptual and numerical models for the sound management of the groundwater resources

Pétré, Marie-Amélie 20 December 2016 (has links)
Dès le début du 20ème siècle, les eaux souterraines de l’aquifère transfrontalier Milk River (MRA) ont constitué une importante ressource dans le sud de l’Alberta (Canada) et le nord du Montana (USA). L’utilisation intensive de cette ressource sous un climat semi-aride a provoqué une baisse importante des niveaux d’eau localement, si bien que des inquiétudes concernant la pérennité du MRA sont apparues dès les années 60. Les études précédentes du MRA étaient limitées par les frontières nationales, empêchant ainsi une compréhension complète de la dynamique de l’aquifère. L’objectif de cette thèse était de réaliser une étude transfrontalière du MRA afin de caractériser cette ressource régionale d’eau souterraine selon ses limites naturelles. À cette fin, trois modèles transfrontaliers ont été réalisés: un modèle géologique, un modèle conceptuel hydrogéologique et un modèle numérique d’écoulement souterrain. Des travaux de terrain de part et d’autre de la frontière Canada/USA et une revue de littérature exhaustive des études précédentes ont supporté la réalisation de ces modèles. De plus, une première évaluation des niveaux d’exploitation historiques du MRA a été réalisée en Alberta.Le modèle géologique 3D (50 000 km2) représente le MRA (Membre Virgelle de la Formation Milk River/Eagle) et ses unités confinantes continûment à travers la frontière internationale. Le développement de ce modèle a requis une harmonisation des nombreuses nomenclatures stratigraphiques de la région et la délimitation transfrontalière du MRA.Le modèle conceptuel hydrogéologique du MRA a montré deux flux d’écoulement souterrains transfrontaliers, dirigés du Montana vers l’Alberta. La Milk River intercepte la majeure partie du flux souterrain venant du sud, si bien que l’écoulement au nord de la rivière est très faible. Les analyses isotopiques confirment que les eaux du MRA sont principalement fossiles à l’exception de la zone de recharge située le long de la zone d’affleurement du MRA. Les zones du MRA avec une forte conductivité hydraulique et de faibles concentrations en chlorures correspondent à des voies d’écoulement préférentielles. L’émergence des eaux du MRA a lieu via la drainance à travers les unités confinantes notamment le long des vallées enfouies.Le modèle numérique (26 000 km2) d’écoulement souterrain du MRA en régime permanent est une transposition des modèles géologique et conceptuel. Il montre que le modèle conceptuel précédemment développé est hydrauliquement plausible. Le modèle d’écoulement donne une meilleure compréhension du système aquifère en représentant la dynamique de l’écoulement souterrain dans la situation pré-exploitation. Le traçage de particules indique des temps de résidence advectifs de près de 750 000 ans à la limite nord du MRA, ce qui est inférieur aux âges obtenus par les analyses isotopiques (2 Ma).Les bilans en eau des modèles conceptuels et numériques montrent tous les deux que l'extraction de l'eau souterraine dépasse de loin la recharge au nord de la Milk River.Un modèle d'écoulement transitoire serait requis pour définir le volume d'eau provenant de l'emmagasinement dans le MRA et préciser le rôle des aquitards durant le pompage. Par ailleurs, en tant que ressource internationale partagée, une gestion transfrontalière des eaux du MRA serait justifiée dans la région comprise entre la zone de recharge au Montana et le sud de la Milk River en Alberta. Ainsi, ces trois modèles transfrontaliers du MRA forment une base commune internationale de connaissances scientifiques à l'échelle de l'aquifère et pourraient supporter l'évaluation future du meilleur usage possible de cette ressource partagée et limitée. De futurs travaux peuvent inclure l'effet des champs de gaz localisés aux limites du MRA et les conditions paléo-hydrogéologiques liées à l'évolution géochimiqie de l'au souterraine. / Since the beginning of the 20th century, groundwater from the Milk River Aquifer (MRA) has been an important water resource in southern Alberta (Canada) and northern Montana (USA). The intensive use of this resource under a semi-arid climate has locally led to important drops in waters levels, thus raising concerns on the MRA sustainability since the 1960’s. Previous MRA studies were limited by the national boundaries, thus preventing a full understanding of the aquifer dynamics. The objective of this thesis was to carry out a transboundary study of the MRA to define this regional groundwater resource within its natural boundaries. For this purpose, three cross-border models were developed: a geological model, a conceptual hydrogeological model and a numerical groundwater flow model. These developments were supported by focused field work on both sides of the Canada/USA border and a comprehensive review of previous studies. Furthermore, a first assessment of the historical exploitation levels of the MRA was done for southern Alberta.The 3D geological model (50,000 km2) continuously represents the MRA (Virgelle Member of the Milk River/Eagle Formation) and confining units through the international border. Development of this model required harmonization of various stratigraphic nomenclatures in the study area and the transboundary delineation of the MRA extent.The hydrogeological conceptual model of the MRA indicated two transboundary groundwater fluxes from Montana to Alberta. The Milk River intercepts most of the groundwater flux incoming from the south, thus leading to limited groundwater flow north of the Milk River. Isotopic analyses confirm that the MRA contains mostly fossil groundwater, with the exception of the recharge area located along the outcrop area of the aquifer. Areas within the MRA with a high hydraulic conductivity and low chloride concentrations correspond to preferential groundwater flowpaths. Discharge from the aquifer occurs as vertical leakage through the overlying confining units, especially along bedrock valleys.The numerical steady-state groundwater flow model of the aquifer system (26,000 km2) is a transposition of the geological and conceptual models, and it shows that the previously developed conceptual model is hydraulically plausible. The groundwater flow model provides a better understanding of the aquifer system by representing the dynamics of groundwater flow under pre-development conditions. Particle tracking indicates advective residence times of up to 750,000 years in the northern limit of the aquifer, which is lower than ages obtained from isotopic analyses (2 Ma).The area south of the Milk River benefits from all of the transboundary groundwater flux from Montana whereas north of the Milk River, only a portion of the recharge flux coming from the south is transmitted due to the interception of the Milk River.Groundwater budgets from both the conceptual and numerical models show that groundwater extraction far exceeds recharge north of the Milk River. A transient model would be required to determine how much water is derived from storage in the MRA and to assess the role of the confining units during pumping. Furthermore, as an internationally shared resource, a transboundary management of the MRA would be appropriate, especially in the area comprised between the recharge area in Montana and the Canadian reach of the Milk River.Together, these transboundary models of the MRA constitute a common international basis of scientific knowledge at the aquifer scale and could support further assessments of the best possible exploitation of the shared but limited resource.Future works could include the study of the effects of the gas fields located at the limits of the MRA as well as paleo-hydrogeological conditions relative to the geochemical evolution of groundwater.

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