On dérive un nouveau modèle d’écoulements cisaillés et turbulents d’eau peu profonde. Les écarts de la vitesse horizontale par rapport à sa valeur moyenne sont pris en compte par une nouvelle variable appelée enstrophie, liée à la vorticité et à l’énergie turbulente. Le modèle comporte trois équations qui sont les bilans de masse, de quantité de mouvement et d’énergie. Le modèle est hyperbolique et peut être écrit sous forme conservative. L’énergie turbulente, dont l’intensité peut être importante, est produite par les ondes de choc qui apparaissent naturellement dans le modèle. Les écoulements rapidement variés étudiés sont caractérisés par l’existence d’une structure turbulente appelée rouleau dans laquelle la dissipation d’énergie turbulente joue un rôle majeur. Cette dissipation, qui détermine notamment le profil de profondeur, est modélisée par l’introduction d’un terme nouveau dans le bilan d’énergie. Le modèle comporte deux paramètres. L’un gouverne la dissipation de l’énergie turbulente du rouleau. L’autre paramètre, l’enstrophie de paroi, liée au cisaillement sur le fond, peut être considéré comme constant dans la partie rapidement variée d’un écoulement, sur laquelle il exerce une influence assez faible. Ce modèle a été appliqué avec succès aux vagues des trains de rouleaux et au ressaut hydraulique classique. Le profil de la surface libre est en très bon accord avec les résultats expérimentaux. L’étude numérique en régime non stationnaire permet notamment de prédire le régime oscillatoire du ressaut hydraulique. La fréquence d’oscillations correspondante est en accord satisfaisant avec les mesures expérimentales de la littérature. / We derive a new model of turbulent shear shallow water flows. The deviation of the horizontal velocity from its average value is taken into account by a new variable called enstrophy, which is related to the vorticity and to the turbulent energy. The model consists of three equations which are the balances of mass, momentum and energy. The model is hyperbolic and can be written in conservative form. The turbulent energy, which can be of high intensity, is produced in shock waves which appear naturally in the model. The rapidly varied flows we studied are characterized by the presence of a turbulent structure called roller in which the turbulent energy dissipation plays a major part. This dissipation, which determines, in particular, the depth profile, is modelled by the introduction of a new term in the energy balance equation. The model contains two parameters. The first one governs the dissipation of the turbulent energy of the roller. The second one, the wall enstrophy, related to the shearing at the bottom, can be considered as constant in the rapidly varied part of the flow on which it does not exert an important influence. This model was successfully applied to roll waves and to the classical hydraulic jump. The free surface profile was found in very good agreement with the experimental results. The numerical study in the non-stationary case can notably predict the oscillations of the hydraulic jump. The corresponding oscillation frequency is in good agreement with the experimental measures found in the literature.

The subject of the thesis is the analysis of the intermodal connection between Czech Republic and the seaports. The importance of this connection for the Czech Republic as for an open economy with a large volume of international trade is undervalued. The connection between Czech Republic and the ports is mainly provided by the container combined transport road -- rail. It is necessary to pay attention to the development of this field as it has a potential to be the most effective way of transport considering both economical and environmental criteria. The aim of the thesis is to survey the issue of intermodal connection with the ports, to evaluate the current status and future development options, including the barriers to this development. The result of the thesis is an analyzed current situation: the ports to which Czech Republic is connected have been determined as well as the modes of transport and the key players on the Czech market that provide the shipping services to the ports. A significant part of attention is paid to METRANS, a.s. which is the leading provider of intermodal transport services between Czech republic and the ports. A major problem associated with the development of combined transport is the harmonization of the conditions between road and rail transport. There is one chapter of the thesis which is devoted to this issue. Thanks to the information obtained from companies operating in the intermodal transport business, it was possible to calculate the costs related to the transport of the consignment by road and rail route, to highlight the problems in the daily operation of combined transport, to identify the weaknesses that may hinder the development of the METRANS or to bring other real outcomes.

Os mapas da cidade de São Paulo, produzidos no período compreendido entre o final do século XIX e meados do século XX, revelam uma cidade em plena transformação e desenvolvimento, com aumento dos seus limites através das obras de infraestrutura, como linha férrea e de bondes, implantação dos sistemas de distribuição de água e principalmente, energia elétrica, além da construção de novas pontes, loteamentos e arruamentos de chácaras, abertura de ruas, avenidas e praças. A influência dos trilhos (trens e bondes) na estruturação territorial da cidade de São Paulo foi avaliada através da análise de mapas históricos e auxiliada pela cartografia digital. Atualmente, com os recursos técnicos disponíveis, os mapas históricos podem ser estudados de forma sistematizada buscando-se obter uma visão de conjunto a respeito das transformações no espaço geográfico ao longo do tempo. A cartografia digital, apoiada nos softwares de Sistemas de Informação Geográfica (SIG), representa essa possibilidade oferecendo recursos para armazenamento, manipulação, e visualização dos dados geográficos. / The maps of the city of São Paulo produced within period from the late nineteenth and mid-twentieth century, reveal a city undergoing transformation and development, increasing the limits of the urban through infrastructure works such as railway and trams, implementation of water distribution systems and especially electricity, in addition to building new bridges, roads and subdivisions of small farms, open streets, avenues and squares. The influence of the rails (trains and trams) in the territorial structure of the city of São Paulo was evaluated through analysis of historical maps and assisted by digital mapping. Currently, with the available technical resources, historical maps can be studied in a systematic way seeking to get an overview about the changes in geographical space over time. The digital cartography supported by Geographic Information Systems (GIS) software provides resources for storage, manipulation, and visualization of geographic data.

Nesta tese estudamos a dinâmica das não linearidades ópticas em compostos orgânicos, mais especificamente em amostras de bis-ftalocianina de itérbio, derivados do álcool furfurílico e compostos azo-aromáticos. Para que a dinâmica dos processos ópticos não lineares pudesse ser investigada nesses materiais, desenvolvemos uma extensão experimental à técnica de varredura-Z convencional, denominada de varredura-Z com trem de pulsos. Nesta técnica, o trem de pulsos de um laser Q-switched/mode-locked é convenientemente empregado para o estudo da dinâmica de processos não lineares no intervalo de 10 a 1000 ns, permitindo a discriminação entre não linearidades rápidas e processos lentos ou acumulativos. Os resultados obtidos através desta técnica nos diversos materiais estudados, complementados com medidas ópticas lineares, tornaram possível a determinação da origem dos processos não lineares refrativos e absorcivos, permitindo também a determinação dos parâmetros espectroscópicos do estado excitado. / This work reports the dynamic nonlinear optical properties of organic compounds, namely, ytterbium bis-phthalocyanine, furfuryl alcohol derivatives and azo-aromatic compounds. In order to carry out this investigation we developed an experimental extension to the standard Z-scan technique, named Z-scan with pulse trains. In this method, pulse trains contained in Q-switched/mode-locked lasers can be advantageously used to study dynamic optical nonlinearities in the 10-1000 ns time interval, allowing the discrimination between fast and slow (cumulative) nonlinear effects. The results obtained in the compounds studied with this technique, complemented with linear optical measurements, permitted the nonlinear refraction and absorption origin to be determined, allowing the characterization of excited state spectroscopic parameters.

Le prochain secteur à être fortement automatisé est sans doute celui du transport routier. D’abord en environnement peu complexe comme c’est déjà le cas sur autoroute, puis à terme dans les scénarios les plus difficiles, comme ceux rencontrés au coeur du trafic urbain. Une étape intermédiaire consiste à introduire des véhicules autonomes en milieu urbain, mais hors du trafic, comme sur des sites fermés. Ces environnements présentent des caractéristiques particulières, comme un encombrement important. Alors, pour être en mesure de naviguer en toute autonomie, les véhicules doivent être à la fois agiles, précis et sûrs, mais aussi efficaces, donc rapides. Ce travail de thèse adresse deux problématiques clés de la navigation autonome en milieu encombré : la planification et le suivi de chemin pour les véhicules à deux trains directeurs (4WS). En effet, la cinématique 4WS est la réponse des constructeurs au besoin d’agilité et nécessite le développement de techniques de commande adaptées. La planification de chemin en temps-réel permet l’évitement d’obstacles, de façon à rendre le service robuste aux aléas de l’environnement. Le contrôle automatique de la direction permet ensuite de suivre ces chemins avec précision. La principale difficulté concernant la planification de chemin est le contraste entre la faible puissance de calcul embarquée sur le véhicule et la forte contrainte temporelle qu’impose le besoin de réactivité. Il s’agit donc de choisir l’approche adéquate et de mettre en place les simplifications algorithmiques les plus efficaces, c’est-à-dire qui réduisent la quantité de calculs nécessaires sans réduire la qualité des chemins générés. De plus, la planification de chemin en milieu encombré pose le problème des impasses dans lesquelles les méthodes les plus réactives restent coincées. De fait, l’approche retenue consiste à construire une fonction de navigation en deux dimensions dont est extrait le chemin. Au sens des critères choisis, il est optimal pour un véhicule circulaire. Des stratégies sont alors mises en place pour adapter cet algorithme aux véhicules 4WS de forme rectangulaire, comme la notion centrale de double-chemin qui permet de représenter la trajectoire d’un mobile à trois degrés de liberté dans un espace en deux dimensions. Enfin, d’autres stratégies et heuristiques sont introduites pour optimiser les performances de l’algorithme de planification et lui permettre de générer des manoeuvres efficaces. Concernant le développement du contrôleur de direction, il s’agit de choisir le modèle d’évolution qui retranscrit au mieux le comportement du véhicule vis-à-vis du double chemin qu’il doit suivre, puis d’en déduire les lois de commande des trains avant et arrière. Ayant été éprouvé par de nombreux travaux, le modèle bicyclette 4WS a été choisi. Ce modèle cinématique permet d’introduire facilement des angles de dérive utiles à la compensation des glissements des pneus sur le sol, qu’ils soient dus à un manque d’adhérence ou à une géométrie imparfaite des trains. Des lois de commande par retour d’état sont ensuite synthétisées et une stratégie de gestion de la saturation des actionneurs est proposée. Enfin, ce premier contrôleur est décliné en une version prédictive qui apporte un suivi de chemin d’une grande stabilité sur les véhicules réels. Les contributions ont toutes été évaluées en simulation et lors d’expérimentations en vraie grandeur sur l’EZ10, une navette électrique 4WS industrielle. Enfin, il se trouve que les performances obtenues dépassent les attentes initiales. / The next sector to be highly automated is probably road transport. First in an uncomplicated environment as is already the case on highway, then eventually in the most difficult scenarios, such as those encountered at the heart of the urban traffic. An intermediate step is to introduce autonomous vehicles in urban areas, but outside traffic, as on closed sites. These environments have particular characteristics, they can be very cluttered. So to be able to navigate autonomously, the vehicles have to be agile, precise and safe, but also efficient, i.e. fast. This thesis addresses two key issues of autonomous navigation in cluttered environments: path planning and tracking for bi-steerable (4WS) vehicles. Indeed, the 4WS kinematics is the response of the manufacturers to the need for agility and requires the development of adapted control techniques. Real-time path planning allows the avoidance of obstacles in order to make the service robust to the vagaries of the environment. The automatic control of the direction then makes it possible to follow these paths with precision. The main difficulty about path planning is the contrast between the low onboard computing power and the high temporal constraints imposed by the need for reactivity. It is thus necessary to choose the appropriate approach and to implement the most efficient algorithmic simplifications, i.e. reducing the amount of calculations without reducing the quality of the generated paths. In addition, path planning in cluttered environment raises the problem of dead-ends in which the most reactive methods remain stuck. Then, the adopted approach consists in constructing a navigation function in two dimensions from which the path is extracted. In the sense of the chosen criteria, it is optimal for a circular vehicle. Strategies are then put in place to adapt this algorithm to 4WS vehicles of rectangular shape, such as the central dual-path concept which allows to represent the trajectory of a mobile with three degrees of freedom in a two-dimensional space. Finally, other strategies and heuristics are introduced to optimize the performance of the planning algorithm and allow it to generate efficient maneuvers. Concerning the development of the controller, it is about choosing the evolution model which best reflects the behavior of the vehicle with respect to the dual-path that it must follow and then deducing the front and rear control laws. The 4WS bicycle model has shown itself to be very effective. This kinematic model makes it possible to easily introduce useful side-slip angles allowing to compensate the slippage of the tires on the ground, whether due to a lack of grip or an imperfect geometry of the axles. State feedback control laws are then synthesized and a strategy for managing the saturation of the actuators is proposed. Finally, this first controller is declined in a predictive version that provides a very stable tracking on real vehicles.The contributions were all evaluated in simulation and in full-scale experiments on the EZ10, an industrial 4WS electric shuttle. Finally, it turns out that the performances exceed initial expectations.

After decades of standstill in intercity passenger rail in the United States, the Obama administration recently started major initiatives to implement high-speed ground transportation projects that are expected to improve the nation's transportation system significantly, addressing most prevailing issues like congestion and energy prices while having positive effects on the economy. This study evaluates and compares two high-speed ground transportation systems that have the potential to improve intercity passenger transportation in the United States significantly: the wheel-on-rail high-speed system and the high-speed maglev system. Both high-speed ground transportation systems were evaluated with respect to 58 characteristics organized into 7 categories associated with technology, environmental impacts, economic considerations, user-friendliness, operations, political factors, and safety. Based on the performance of each system in each of the 58 characteristics, benefit values were assigned. In order to weight the relative importance of the different characteristics, a survey was conducted with transportation departments and transportation professionals. The survey produced weighting factors scoring each of the 58 characteristics and the 7 categories. Applying a multi-criteria decision making (MCDM) approach, the overall utility values for either system were calculated based on the benefit values from the systems comparison and the weighting factors from the survey. It was shown that the high-speed maglev system is generally slightly superior over the wheel-on-rail high-speed system. Because the magnitude of the difference in the overall performance of both transportation systems is not very big, it is recommended that every project in the high-speed intercity passenger transportation market consider both HSGT systems equally.

Changes in climate caused by changes in anthropogenic (i.e. "man-made") greenhouse gas (GHG) emissions have become a major public policy issue in countries all over the world. With an estimated 28.4% of these emissions attributed to the transportation sector, attention is being focused on strategies aimed at reducing transportation GHG emissions. Quantifying the change in GHG emissions due to such strategies is one of the most challenging aspects of integrating GHG emissions and climate change into transportation planning and policy analysis; the inventory techniques and methods for estimating the impact of different strategies and policies are still relatively unsophisticated. This research developed a method for estimating intercity passenger transportation energy and carbon footprints and applied this method to three US DOT-designated high speed rail (HSR) corridors in the U.S.-- San Francisco/Los Angeles/San Diego; Seattle/Portland/Eugene, and Philadelphia/Harrisburg/Pittsburg. The methodology consists of estimating the number of trips by mode, estimating the direct CO₂ emissions, and estimating indirect CO₂ emissions. For each study corridor the impacts of different strategies and policies on carbon dioxide emissions were estimated as an illustration of the policy application of the developed methodology. The largest gain in CO₂ savings can be achieved by strategies aiming at automobile emissions, due to its sizeable share as main mode and access/egress mode to and from airports and bus and train stations: an average fuel economy of 35.5 mpg would result in a 38-42% savings of total CO₂ emissions; replacing 25% of gasoline use with cellulosic ethanol can have a positive impact on CO₂ emissions of about 13.4-14.5%; and a 10% market share for electric vehicles would result in potential CO₂ savings of 3.4-7.8%. The impact of a 20% or 35% improvement in aircraft efficiency on CO₂ savings is much lower (0.88-3.65%) than the potential impacts of the policies targeting automobile emissions. Three HSR options were analyzed using Volpe's long-distance demand model: HSR125, HSR150, and HSR200. Only the HSR150 and HSR200 would result in CO₂ savings, and then just for two of the three corridors: the Pacific Northwest (1.5%) and California (0.8-0.9%). With increased frequency and load factors, a HSR150 system could result in CO₂ savings of 5.2% and 1.8% for the Pacific Northwest and California, respectively. This would require a mode shift from auto of 5-6%. This shift in auto mode share would mainly have to be a result of pricing strategies. From these results, HSR may not be such an obvious choice, however, with increased ridership and diversions from other modes, CO₂ savings increase significantly due to the lower emissions per passenger mile for HSR. The framework developed in this study has the ability to determine the GHG emissions for such HSR options and increased diversions.

The Austin Steam Train Association operates a tourist train on a stretch of track in Texas from Cedar Park to Burnet. The diverse assortment of restored cars, some dating back to the 1920s, is pulled most-recently by a diesel engine, No. 442, as Southern Pacific No. 786, the original steam engine, is in the process of being repaired. The train requires more than $1 million annually to operate and would have folded long ago if not for an all-volunteer crew. ASTA staffs the crew of at least 10-15 people per train 105-110 times per year and has been doing so for more than 20 years. During a ride on the train, passengers see a wide variety of scenery, including some relics with historical significance. Among them are several large chunks of granite which fell of trains shuttling the stone decades ago from Marble Falls to Austin for the construction of the capitol building. Trains also carried granite to Galveston after the infamous hurricane hit. ASTA also provides entertainment inside the train. Themes rides sell out months in advance. Murder mystery trips are always hits but the Wine Flyer is gaining popularity. With a layover in Burnet on the Saturday Hill Country Flyers trips, passengers take time to explore a new city, have lunch and maybe do a little quick shopping. ASTA takes the operation of the train seriously and makes safety a priority. ASTA runs the train with fantastic dedication and perseverance and subsequently, generates a rolling work of history for study by families, first-timers and enthusiasts alike on a weekly basis. / text

M. Tech. Electrical Engineering. / Aims to develop these railways applications for a better use of the electrical power to reduce pollution and consumption. The specification of this project is to improve the conversion of the electrical energy. This also involves improving the connection between the train and the electrical networks using the pantograph. In this research, I will propose a new architecture for the converters and a structure to provide to the grid the electricity generated through braking. Another point regards the command of the converters, which is directly involved in the system behaviour. In order to obtain the best behaviour possible, a different control as usual will be described and modelled to reduce the total harmonics distortion rate and reach a better efficiency.

Ultra deep mining presents many challenges to the mining engineer, one of which is the logistics to support mining operations quickly and efficiently. Typically, Witwatersrand gold mines operate at depths in excess of 2000 m with stoping taking place to 3500 m and investigations underway to mine to a depth of 5000 m. As mining progresses deeper and further from the shaft, the role of logistics becomes increasingly important if production targets are to be achieved. Access to the workings is often via sub vertical and even tertiary subvertical shaft systems with working faces as far as five kilometers from the shaft. It is inevitable therefore, that distance will negatively impact the working time available at the stope face, material transportation and distribution, as well as the removal of broken ore. Possible solutions to these logistical problems may be found in the use of different transportation systems or by applying sound design and operational principles to transportation systems, both in the horizontal and instope areas. This thesis investigates the challenges of logistics for ultra deep level gold mining in the Witwaterstrand basin for mining layouts planning to mine between 3000 m and 5000 m underground with typical horizontal distances of over 3000 m. The transportation needs analysis recognised that vertical transportation is a wellmanaged and organised system and is mainly the same for both shallow and deep level operations. As a result of this, the thesis only focuses on the logistical issues of the horizontal and in-stope processes. The literature review indicates that the majority of work previously conducted on transportation focused around the area of horizontal transportation with limited inputs to in-stope transportation systems. The review concludes that the traditional locomotive transportation system is the most applicable mode of horizontal transportation. Thus, special emphasis is given to trackbound transportation. An integrated approach is taken towards mine transportation advocating that underground logistics be considered as equally important as any other discipline, Le. rock engineering, ventilation, etc. In addition, the transportation process should consider each area equally important. All to often, the transportation of rock is considered of paramount importance over the transportation of personnel and material. Thus, the planning any transportation system should incorporate personnel, material and rock. To enable this, scheduling, communication and control are important with special attention required for transfer points in the transportation system. As each site has its own particular requirement, thus the final transportation systems must be drawn up based on the specific requirements of each mine. A guideline is proposed for the design of ultra deep level underground transport systems for personnel, material and rock transportation. Thus, providing mining engineers with sufficient information and data to select an appropriate transportation system to meet specific mine requirements. The thesis highlights areas requiring consideration by mine engineers when designing a transportation system from shaft to the working face. / Thesis (Ph.D.)-University of Natal, Durban, 2003.