En el presente trabajo se toma el problema de la contaminación ambiental, en concreto la / contaminación aérea a través de la quema de combustibles fósiles, y se diseña una / alternativa ecológica para una de las muchas aplicaciones en las que son utilizados. A / manera de introducción se brinda un breve contexto de la situación actual. Se enuncian los / objetivos generales y específicos del proyecto y a continuación se plantea una hipótesis. La / meta del proyecto es crear un colector solar en V útil para comunidades rurales y personas / de escasos recursos, para esto, se establece un marco teórico donde se parte de lo general / mencionando como primer tema la contaminación ambiental. Aquí se discute su origen y se / da paso a una de sus principales consecuencias, el calentamiento global. Se analiza la / utilización de las energías no renovables, como lo son el petróleo, el carbón, la energía / nuclear, el gas natural y el gas LP. Este ultimo de gran importancia para el proyecto, ya que / es el más utilizado para calentar agua en México. / (cont.) En contraparte de las energías no / renovables, se estudian las energías renovables, como lo son la eólica, hidráulica, / mareomotriz, geotérmica, undimotriz y solar, donde se hace especial hincapié en la solar, / pues es la fuente de energía del diseño del colector solar. Como última aportación en el / marco teórico se hace un análisis de los calentadores en el mercado, en el cual se fija la / atención en el aspecto económico y las principales ventajas y desventajas de estos. / En cuanto al diseño del proyecto se establecen los lineamientos a seguir en la / construcción del colector solar, los materiales a utilizar y las pruebas experimentales con / las que se prueba su efectividad. Como parte primordial del objetivo, se comparan / diferentes materiales reflejantes, para que se pueda decidir el material a utilizar en el / proyecto. Se prueba el prototipo de calentador con diferentes capacidades y situaciones, / esto para establecer puntos de referencia objetivos y precisos de los cuales se inferirán los / resultados a escalas mayores. Además, se realiza una prueba para determinar la cantidad de / energía solar disponible en un día soleado promedio. / (cont.) A continuación se discuten los / resultados de las pruebas realizadas, donde se establecen datos precisos y claros acerca del / funcionamiento del colector solar en V. También, se lleva a cabo un análisis de costos de / los materiales utilizados en la fabricación del prototipo de colector solar en V, donde se dan / diferentes opciones de construcción y se analiza cual es la mejor forma de hacerlo. / Por último, se ofrece un capítulo de conclusiones y recomendaciones, donde se / plantean las conclusiones a las cuales se llegaron por medio de este trabajo, y se hacen / recomendaciones de construcción en caso de llevar a cabo la fabricación de un colector / solar en V, o de continuar con la investigación para un mejoramiento de los datos y una / mayor eficiencia del aparato.

Texte remanié de: Thèse de doctorat--Droit privé--Paris 1, 2005. / En appendice, projet de code civil chinois. Bibliogr. p. 387-426. Index.

Inaug.-Diss.--Bern. / Vita. Bibliography p. 102-103.

Thesis (M.A.)--University of Hong Kong, 1993.

Thesis (M.A.)--University of Hong Kong, 1993. / Also available in print.

Inaug.-Diss.--Freiburg i. B. / Cover title. Lebenslauf. "Schrifttumsverzeichnis": pp. 6-9.

<p>Increased interest in rational approaches to flexible pavement design, rather than the usual empirical methods, has brought about an urgent need for a better understanding of the material properties involved. In this study, laboratory equipment capable of providing reliable measurements of the material properties for asphaltic concrete mixes, under variable stress and temperature conditions has been developed. The basic material properties obtained from these measurements are the resilient modulus (MR) and dynamic Poisson's ratio (v), which are the required inputs for the elastic analysis of flexible pavement structures.</p> <p>Tests have indicated that temperature is the main parameter affecting the resilient modulus of asphaltic concrete mixes, with deviator stress and confining pressure secondary in effect. Based on tests performed on a few samples, the dynamic Poisson's ratio was found to increase with temperature from about 0.24 at 10ºC (50ºF) to approximately 0.46 at 42ºC (108ºF). Confining pressure was found to have little or no effect on the dynamic v.</p> <p>Analysis using a linear elastic flexible pavement computer programme has indicated a significant reduction in...a mix with a higher MR value. This demonstrates the advantage of utilizing the structural analysis approach to flexible pavement design for more efficient use of materials.</p> / Master of Engineering (ME)

<p>In recent years, the use of tuned liquid dampers (TLD) as dynamic vibration absorbers has increased in popularity due to their low cost and ease of installation. A TLD is a partially fluid filled tank (commonly water) that has a fundamental sloshing frequency close to the natural frequency of the structure in the vibration mode to be suppressed. Typically, water alone is insufficient to achieve the required level of optimal damping. One approach that is used to increase the damping of the TLD is to install flow damping devices (screens) into the tank. In this study horizontal slat screens are selected for investigation. For a given target response acceleration an optimal level of damping can be achieved. However, as the structural response deviates from this target value the efficiency of the structure-TLD system is significantly reduced. To increase the efficiency, an investigation into the applicability of slat screens with a varying loss coefficient is undertaken in this study.</p> <p>A TLD equipped with slat screens bf different slat heights, edge geometries, and solidities is experimentally investigated. The TLD is subjected to shake-table tests under sinusoidal excitation for a range of amplitudes that correspond to a practical range of peak hourly horizontal structural accelerations. The variation in screen losses (C_L) is correlated with the Keulegan-Carpenter (<em>KC</em>) number.</p> <p>An equivalent mechanical model is utilized by analyzing the TLD as an equivalent tuned mass damper (TMD). In addition, a nonlinear numerical model based on shallow water theory is investigated. The influence of slat height on the free surface response, base shear forces, and energy dissipation is assessed.</p> <p>A TLD equipped with various screen geometries is mathematically modelled in a hypothetical structure-TLD system. This system demonstrates the ability of slat screens with a varying loss coefficient to maintain a near optimum level of damping over a wide range of structural accelerations.</p> / Master of Applied Science (MASc)

<p>Tuned-liquid dampers (TLDs) can be used as vibration absorbers for tall buildings. The ability of TLDs to decrease a building's motions is highly dependent on them being tuned to the building's natural frequency. In the present study natural frequency and damping estimates are determined for a 187 m tall building equipped with TLDs. A properly tuned structure-TLD system acts as a coupled two-degree-of-freedom (2DOF) system. In this study several MATLAB (2009) programs were developed in order to determine the dynamic properties of both single-degree-of-freedom (SDOF) and 2DOF systems. These programs Were based on the statistical maximum likelihood (ML) and least squares (LS) methods. The ML programs are based on earlier work by Montpellier (1997) and the LS programs were developed independently. All of the programs were verified using spectral and time-history data with known dynamic properties. The results of the programs were also compared to results generated by the well-known half-power bandwidth and random decrement methods: The ML and LS programs were found to produce results that were superior to the half-power bandwidth method and comparable to the random decrement program for SDOF systems. The ML and LS programs are superior to the half-power bandwidth and random decrement programs for analyzing coupled 2DOF systems as they are able to determine distinct property estimates for each mass. The natural frequency of the building studied for this project was found to be significantly higher than predicted at the time of its design. Thus the TLDs were not optimally tuned to the building's actual natural frequency and as a result the studied building was behaving as a SDOF system. Therefore the dynamic properties estimated in this study are those of a SDOF system. However, the methods developed herein could be applied to a 2DOF system in the future.</p> / Master of Applied Science (MASc)

<p>p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times}</p> <p>The objective of this thesis is to investigate the potential of ensemble</p> <p>meteorological forecasts (15 members for each day) in improving ensemble flow</p> <p>prediction up to 14 days ahead. Large scale ensemble meteorological forecasts generated</p> <p>by the National Centers for Environmental Prediction's (NCEP) Global Forecast System</p> <p>(GFS) are used. The hydrologic model used in watershed analysis of the study area is</p> <p>Hydrologiska Byrâns Vattenbalan-avdelning (HBV). The study area is located in the</p> <p>Saguenay-Lac-Saint Jean watershed in northeastern Canada and comprises the Serpent</p> <p>River and Chute-du-Diable basins and a reservoir in Chute-du-Diable.</p> <p>The NCEP ensemble meteorological forecast data is initially used as input in the p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times} span.s1 {font: 7.5px Helvetica}</p> <p>hydrological model HBV to simulate ensemble reservoir inflows and the Serpent River</p> <p>flows for 5 to 14 days ahead. The ensemble inflow and flow forecasts are compared with</p> <p>the case where only observed historical data are used. The study results show that there is</p> <p>a significant improvement in the model forecast performance when NCEP forecast data</p> <p>are used. The improvement for 5 to 14 day forecasts is revealed by an approximately 20%</p> <p>decrease in root mean square error (RMSE) for both reservoir inflow and river flow. A</p> <p>decrease in the Brier score (BS) and rank probability score (RPS) indicates considerable</p> <p>improvement and an increase in the correlation coefficient (r) and the Nash and Sutcliffe</p> <p>coefficient (R²) is shown for reservoir inflow and the Serpent River flow respectively,</p> <p>indicating the advantage of using NCEP data. This improvement is also revealed by the p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.5px Times}</p> <p>visual inspection of scatter plots, hydrographs of ensemble mean and ensemble members.</p> <p>The hydrologic forecasts are also assessed on a seasonal basis indicating an improvement</p> <p>in forecasting indicated by a 30% decrease in RMSE during the spring season, and a</p> <p>decrease in BS and RPS values. For other seasons, specifically autumn and summer, the</p> <p>use of the ensemble meteorological forecasts do not provide significant improvement</p> <p>because of the poor skill of predicted precipitation. More accurate predictions of reservoir</p> <p>inflow and river flow with adequate lead time will assist in improving relevant issues in</p> <p>water resources management and planning.</p> / Master of Applied Science (MASc)