963 resultados para Automobiles, Racing -- Aerodynamics


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Phénomène à haute prévalence dans le monde entier, les infections acquises au cours de la prestation de soins de santé constituent une menace importante pour la santé publique. Il sâagit dâune réalité inéluctable du système de santé qui touche de nombreuses victimes en les affectant de dommages variés. Fruit dâune interaction complexe entre divers facteurs, ces infections représentent un lourd fardeau pour les victimes comme pour la société, tant au plan physique, mental et financier. Bien que les infections nosocomiales semblent être au cÅur des préoccupations des autorités sanitaires québécoises, lâindemnisation des victimes demeure problématique. Actuellement, lâindemnisation se fait via le régime traditionnel de responsabilité civile mais nombreux sont les obstacles auxquels font face les patients désirant obtenir compensation. Les règles classiques sâavèrent difficiles dâapplication dans un contexte où la source de lâinfection est souvent inconnue et les facteurs ayant pu contribuer à son développement sont multiples. Face à cette problématique et à lâinsatisfaction ressentie, certaines juridictions étrangères ont reconnu le caractère inadapté du régime traditionnel et ont implanté un régime dâindemnisation sans égard à la faute dans lâespoir dâaméliorer le sort des victimes. Le Québec a opté pour la même solution dans divers domaines, tels que les accidents automobiles et la vaccination. Ce mémoire propose une étude approfondie de lâopportunité dâadopter, en droit québécois, un régime dâindemnisation sans égard à la faute bénéficiant aux victimes dâinfections nosocomiales. Lâobjectif de ce projet est de faire une esquisse des caractéristiques assurant lâefficacité et la viabilité dâun tel régime.

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Cette thèse fait la lumière sur les différentes manières dont, historiquement, a été perçu, conçu et vécu le territoire, à travers lâexpérience et lâessor de la mobilité. Cette étude montre le rôle crucial de lâautomobilité dans le développement touristique du Québec et de lâOntario et les manières dont elle a façonné certains de leurs territoires. La thèse reconstitue ces processus en examinant les différentes mesures adoptées pour mettre en tourisme ces territoires et les transformer sur le plan matériel comme symbolique, entre 1920 et 1967. Elle répond à la question suivante : en quoi et comment la mobilité associée à lâautomobile transforme et crée les territoires touristiques? La période étudiée sâouvre au moment où débute lâintervention gouvernementale en matière de tourisme et sâamorce lâaménagement dâinfrastructures favorisant une plus grande automobilité. Elle se clôt sur les célébrations entourant le Centenaire du Canada et la tenue de lâExpo 1967 à Montréal, qui donnent lieu à un aménagement intense du territoire afin dâaccommoder un nombre sans précédent de touristes motorisés en provenance des autres provinces canadiennes et des Ãtats-Unis. La thèse reconstitue dâabord le processus de mise en tourisme des territoires par la conception, la construction et la promotion du système routier, lâélaboration dâitinéraires et de circuits touristiques et le développement dâoutils accompagnant le touriste dans sa mobilité. Lâembellissement en tant quâélément structurant de la transformation des territoires est ensuite examiné. Enfin, la publicité, les récits et les pratiques touristiques sont étudiés de manière détaillée afin dâidentifier les mécanismes par lesquels se construisent les représentations des territoires par lâapport de différents acteurs. Cette thèse révèle ainsi les liens étroits et complexes qui se développent à partir des années 1920 entre lâautomobilité, le tourisme et la modification des territoires. Elle contribue à mettre au jour lâhistoricité de certains réflexes et orientations qui ont encore cours dans lâindustrie touristique canadienne soit ceux dâaborder son développement en fonction de lâaccessibilité du territoire à lâautomobile et du regard à travers le pare-brise. En montrant le rôle du système automobile dans lâexpérience touristique, lâétude ajoute un élément nouveau à la compréhension de la démocratisation des loisirs. Souvent expliquée par la hausse du niveau de vie, du temps libre et de la généralisation des congés payés, cette démocratisation se trouve aussi favorisée par lâaccessibilité à lâautomobile qui, à son tour, rend accessible des territoires de plus en plus éloignés à des fins de loisirs. La dimension récréative de lâautomobile permet dâexpliquer son adoption rapide par les Nord-Américains et les Canadiens ainsi que la dépendance quâils ont progressivement développée à son égard.

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Le campus de lâUniversité de Montréal est composé de bâtiments et dâaménagements paysagers hautement significatifs, dont la présence contribue à faire comprendre son évolution spatiale. Parmi eux, les espaces libres des années 1960 méritent une attention particulière pour plusieurs raisons historiques : ils font lâobjet dâune réflexion pour la toute première fois dans lâhistoire du campus ; lâUniversité de Montréal vit une phase dâexpansion sans précédent ; les disciplines de lâaménagement et la pratique de planification émergent au Québec. Cet article présente de manière contextuelle les principes de planification qui ont mené à leur réalisation par La Haye et associés, firme dâurbanisme de premier plan au Québec. Il expose les qualités et les défauts des espaces libres de cette période moderne, soit lâinnovation sur le plan de la vision planificatrice et du design, dâun côté, et la trop grande importance accordée aux automobiles au détriment de la sécurité et de la convivialité, de lâautre côté.

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The objectives of the present study are to provide a systematic descriptive documentation of the nature of air pollution of the Cochin industrial agglomeration, estimate the willingness to pay for morbidity reduction due to air pollution in observed and hypothetical markets and to estimate the value of welfare loss in the purchase of property due to reduced air quality. This study is an attempt to examine economic impacts of air pollution on the human health and property values in the industrial capital of Kerala. The process of industrialization in Kerala and the increase in air pollution created damages to human, natural and economic resources in the state. The study documents the extent of air pollution and applied econometric approaches to estimate economic impacts of air pollution on human health and property values. The Important sources of air pollution identified in Cochin are emissions from industries and automobiles.

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The present study deals with the short isora fibre reinforced natural rubber composites. In recent years there has been a tremendous advancement in the field of science and technology of short fibre reinforced polymer composites. The low density, high strength, high stiffness to weight ratio, excellent durability and design flexibility are the primary reasons for their use in many diversified fields such as air crafts, automobiles, marine industry etc. Compared to the various natural and synthetic fibres used as reinforcement for elastomer composites isora fibre is superior in many aspects. `Isora' is a natural lignocellulosic fibre which is easily available in South India especially in Kerala. The fibre is separated from the bark of the Helicteres isora plant by retting process. This fibre has excellent mechanical properties and is easily amenable to physical and chemical modifications. The study shows that composites with poor interfacial bonding tend to dissipate more energy than that with to interfacial bonding. The mechanical loss also can be related to interfacial bonding. The effect of chemical treatment of isora fibre on damping was also studied. Both in the low and high temperature region which indicates that this composite posseses low damping and hence good interfacial bonding characteristics. Hence these composites are better candidates for high damping applications. Composites with longitudinally oriented fibres showed high storage modulus than transversely oriented ones due to the effective stress transfer between fibre and matrix.

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Wind energy has emerged as a major sustainable source of energy.The efficiency of wind power generation by wind mills has improved a lot during the last three decades.There is still further scope for maximising the conversion of wind energy into mechanical energy.In this context,the wind turbine rotor dynamics has great significance.The present work aims at a comprehensive study of the Horizontal Axis Wind Turbine (HAWT) aerodynamics by numerically solving the fluid dynamic equations with the help of a finite-volume Navier-Stokes CFD solver.As a more general goal,the study aims at providing the capabilities of modern numerical techniques for the complex fluid dynamic problems of HAWT.The main purpose is hence to maximize the physics of power extraction by wind turbines.This research demonstrates the potential of an incompressible Navier-Stokes CFD method for the aerodynamic power performance analysis of horizontal axis wind turbine.The National Renewable Energy Laboratory USA-NREL (Technical Report NREL/Cp-500-28589) had carried out an experimental work aimed at the real time performance prediction of horizontal axis wind turbine.In addition to a comparison between the results reported by NREL made and CFD simulations,comparisons are made for the local flow angle at several stations ahead of the wind turbine blades.The comparison has shown that fairly good predictions can be made for pressure distribution and torque.Subsequently, the wind-field effects on the blade aerodynamics,as well as the blade/tower interaction,were investigated.The selected case corresponded to a 12.5 m/s up-wind HAWT at zero degree of yaw angle and a rotational speed of 25 rpm.The results obtained suggest that the present can cope well with the flows encountered around wind turbines.The areodynamic performance of the turbine and the flow details near and off the turbine blades and tower can be analysed using theses results.The aerodynamic performance of airfoils differs from one another.The performance mainly depends on co-efficient of performnace,co-efficient of lift,co-efficient of drag, velocity of fluid and angle of attack.This study shows that the velocity is not constant for all angles of attack of different airfoils.The performance parameters are calculated analytically and are compared with the standardized performance tests.For different angles of ,the velocity stall is determined for the better performance of a system with respect to velocity.The research addresses the effect of surface roughness factor on the blade surface at various sections.The numerical results were found to be in agreement with the experimental data.A relative advantage of the theoretical aerofoil design method is that it allows many different concepts to be explored economically.Such efforts are generally impractical in wind tunnels because of time and money constraints.Thus, the need for a theoretical aerofoil design method is threefold:first for the design of aerofoil that fall outside the range of applicability of existing calalogs:second,for the design of aerofoil that more exactly match the requirements of the intended application:and third,for the economic exploration of many aerofoil concepts.From the results obtained for the different aerofoils,the velocity is not constant for all angles of attack.The results obtained for the aerofoil mainly depend on angle of attack and velocity.The vortex generator technique was meticulously studies with the formulation of the specification for the right angle shaped vortex generators-VG.The results were validated in accordance with the primary analysis phase.The results were found to be in good agreement with the power curve.The introduction of correct size VGs at appropriate locations over the blades of the selected HAWT was found to increase the power generation by about 4%

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From the early stages of the twentieth century, polyaniline (PANI), a well-known and extensively studied conducting polymer has captured the attention of scientific community owing to its interesting electrical and optical properties. Starting from its structural properties, to the currently pursued optical, electrical and electrochemical properties, extensive investigations on pure PANI and its composites are still much relevant to explore its potentialities to the maximum extent. The synthesis of highly crystalline PANI films with ordered structure and high electrical conductivity has not been pursued in depth yet. Recently, nanostructured PANI and the nanocomposites of PANI have attracted a great deal of research attention owing to the possibilities of applications in optical switching devices, optoelectronics and energy storage devices. The work presented in the thesis is centered around the realization of highly conducting and structurally ordered PANI and its composites for applications mainly in the areas of nonlinear optics and electrochemical energy storage. Out of the vast variety of application fields of PANI, these two areas are specifically selected for the present studies, because of the following observations. The non-linear optical properties and the energy storing properties of PANI depend quite sensitively on the extent of conjugation of the polymer structure, the type and concentration of the dopants added and the type and size of the nano particles selected for making the nanocomposites. The first phase of the work is devoted to the synthesis of highly ordered and conducting films of PANI doped with various dopants and the structural, morphological and electrical characterization followed by the synthesis of metal nanoparticles incorporated PANI samples and the detailed optical characterization in the linear and nonlinear regimes. The second phase of the work comprises the investigations on the prospects of PANI in realizing polymer based rechargeable lithium ion cells with the inherent structural flexibility of polymer systems and environmental safety and stability. Secondary battery systems have become an inevitable part of daily life. They can be found in most of the portable electronic gadgets and recently they have started powering automobiles, although the power generated is low. The efficient storage of electrical energy generated from solar cells is achieved by using suitable secondary battery systems. The development of rechargeable battery systems having excellent charge storage capacity, cyclability, environmental friendliness and flexibility has yet to be realized in practice. Rechargeable Li-ion cells employing cathode active materials like LiCoO2, LiMn2O4, LiFePO4 have got remarkable charge storage capacity with least charge leakage when not in use. However, material toxicity, chance of cell explosion and lack of effective cell recycling mechanism pose significant risk factors which are to be addressed seriously. These cells also lack flexibility in their design due to the structural characteristics of the electrode materials. Global research is directed towards identifying new class of electrode materials with less risk factors and better structural stability and flexibility. Polymer based electrode materials with inherent flexibility, stability and eco-friendliness can be a suitable choice. One of the prime drawbacks of polymer based cathode materials is the low electronic conductivity. Hence the real task with this class of materials is to get better electronic conductivity with good electrical storage capability. Electronic conductivity can be enhanced by using proper dopants. In the designing of rechargeable Li-ion cells with polymer based cathode active materials, the key issue is to identify the optimum lithiation of the polymer cathode which can ensure the highest electronic conductivity and specific charge capacity possible The development of conducting polymer based rechargeable Li-ion cells with high specific capacity and excellent cycling characteristics is a highly competitive area among research and development groups, worldwide. Polymer based rechargeable batteries are specifically attractive due to the environmentally benign nature and the possible constructional flexibility they offer. Among polymers having electrical transport properties suitable for rechargeable battery applications, polyaniline is the most favoured one due to its tunable electrical conducting properties and the availability of cost effective precursor materials for its synthesis. The performance of a battery depends significantly on the characteristics of its integral parts, the cathode, anode and the electrolyte, which in turn depend on the materials used. Many research groups are involved in developing new electrode and electrolyte materials to enhance the overall performance efficiency of the battery. Currently explored electrolytes for Li ion battery applications are in liquid or gel form, which makes well-defined sealing essential. The use of solid electrolytes eliminates the need for containment of liquid electrolytes, which will certainly simplify the cell design and improve the safety and durability. The other advantages of polymer electrolytes include dimensional stability, safety and the ability to prevent lithium dendrite formation. One of the ultimate aims of the present work is to realize all solid state, flexible and environment friendly Li-ion cells with high specific capacity and excellent cycling stability. Part of the present work is hence focused on identifying good polymer based solid electrolytes essential for realizing all solid state polymer based Li ion cells.The present work is an attempt to study the versatile roles of polyaniline in two different fields of technological applications like nonlinear optics and energy storage. Conducting form of doped PANI films with good extent of crystallinity have been realized using a level surface assisted casting method in addition to the generally employed technique of spin coating. Metal nanoparticles embedded PANI offers a rich source for nonlinear optical studies and hence gold and silver nanoparticles have been used for making the nanocomposites in bulk and thin film forms. These PANI nanocomposites are found to exhibit quite dominant third order optical non-linearity. The highlight of these studies is the observation of the interesting phenomenon of the switching between saturable absorption (SA) and reverse saturable absorption (RSA) in the films of Ag/PANI and Au/PANI nanocomposites, which offers prospects of applications in optical switching. The investigations on the energy storage prospects of PANI were carried out on Li enriched PANI which was used as the cathode active material for assembling rechargeable Li-ion cells. For Li enrichment or Li doping of PANI, n-Butyllithium (n-BuLi) in hexanes was used. The Li doping as well as the Li-ion cell assembling were carried out in an argon filled glove box. Coin cells were assembled with Li doped PANI with different doping concentrations, as the cathode, LiPF6 as the electrolyte and Li metal as the anode. These coin cells are found to show reasonably good specific capacity around 22mAh/g and excellent cycling stability and coulombic efficiency around 99%. To improve the specific capacity, composites of Li doped PANI with inorganic cathode active materials like LiFePO4 and LiMn2O4 were synthesized and coin cells were assembled as mentioned earlier to assess the electrochemical capability. The cells assembled using the composite cathodes are found to show significant enhancement in specific capacity to around 40mAh/g. One of the other interesting observations is the complete blocking of the adverse effects of Jahn-Teller distortion, when the composite cathode, PANI-LiMn2O4 is used for assembling the Li-ion cells. This distortion is generally observed, near room temperature, when LiMn2O4 is used as the cathode, which significantly reduces the cycling stability of the cells.

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In this paper a precorrected FFT-Fast Multipole Tree (pFFT-FMT) method for solving the potential flow around arbitrary three dimensional bodies is presented. The method takes advantage of the efficiency of the pFFT and FMT algorithms to facilitate more demanding computations such as automatic wake generation and hands-off steady and unsteady aerodynamic simulations. The velocity potential on the body surfaces and in the domain is determined using a pFFT Boundary Element Method (BEM) approach based on the Greenâs Theorem Boundary Integral Equation. The vorticity trailing all lifting surfaces in the domain is represented using a Fast Multipole Tree, time advected, vortex participle method. Some simple steady state flow solutions are performed to demonstrate the basic capabilities of the solver. Although this paper focuses primarily on steady state solutions, it should be noted that this approach is designed to be a robust and efficient unsteady potential flow simulation tool, useful for rapid computational prototyping.

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Estudi de lâeficiència aerodinàmica de les carrosseries de vehicles pesants de cara a reduir el consum de combustible en autocars de llarg trajecte. Lâestudi es basa en tres aspectes: validació del programa de simulació, estudi aerodinàmic de diferents carrosseries dâautocar de mercat i estudi aerodinàmic de diferents complements

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L' objectiu d' aquest estudi és intentar millorar l' aerodinàmica de la nova carrosseria del vehicle de baix consum de la UdG,l' Ãliga, a través de programes informàtics de CFD. Des de fa uns anys l' Escola Politècnica Superior de la Universitat de Girona participa a l' Eco Shell Marathon, mirant d' assolir els millors resultats possibles.El nom del vehicle utilitzat per aquesta carrera és l' Ãliga. Aquest projecte parteix dels resultats obtinguts al Projece fi de carrera d' en Daniel Vilavedra Vilà (2006):"Redisseny aerodinàmic de la carrosseria del vehicle de baix consum Ãliga"

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Investigacions recents revelen com lâacció del vent lateral és un efecte molt important en bona part dels accidents ocorreguts en vehicles pesants de transport per carretera. Ãs per això que el perfil aerodinàmic del vehicle esdevé determinant en lâavaluació de les forces laterals que hi actuen. El present projecte té per objecte determinar les forces laterals que sâexerceixen en vehicles pesants de transport de passatgers degut a lâacció del vent i investigar-ne la seva perillositat. Per fer-ho sâutilitzen models numèrics de dinàmica de fluids i, per diferents velocitats del vehicle, es simulen vents amb diferent intensitat i direcció. Dâaquí es determinen unes condicions de perillositat en funció, entre dâaltres variables, de lâangle dâincidència del vent i de la seva velocitat

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El objetivo primordial de este proyecto es establecer y documentar las condiciones de confort climático y desarrollar un modelo dummy capaz de interpretar la sensación térmica teniendo en cuenta factores internos como; temperatura, velocidad, y dirección del aire.La simulación numérica se realizará con el código Star CCM + de CD- ADAPCO

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A la física o a lâenginyeria es defineix com fregament o fricció a la resistència que s'oposa a la rotació o al lliscament d'un cos sobre un altre, o també a la força que apareix en la superfície de contacte de dos cossos quan s'intenta lliscar un sobre un altre. El fregament ha estat fins avui dia un gran problema físic, això és degut a que genera imperfeccions, especialment microscòpiques, entre les superfícies en contacte. Aleshores és quan apareix la tribologia. La tribologia és la ciència que estudia la fricció, el desgast i la lubricació de superfícies en contacte. El lliscament entre superfícies sòlides es caracteritza generalment per un alt coeficient de fricció i un gran desgast a causa de les propietats específiques de les superfícies. La lubricació consisteix en la introducció d'una capa intermèdia d'un material aliè entre les superfícies en moviment. En aquest projecte hem intentat aplicar tècniques i mètodes de control els quals puguin arribar a millorar i perfeccionar els sistemes de mesura i control a nivell industrial i/o particular. En el nostre cas ha estat lâestudi dels olis lubricants usats en motors de combustió interna de variats vehicles com motocicletes, automòbils, camions o vaixells. Hem introduït una millora dâautomatització mitjançant un circuit pneumàtic al captador de partícules, hi hem introduït una tècnica per captar partícules a partir de filtres de membrana, hem estudiat les mostres i llurs ferrogrames i membranes amb la finalitat de detectar les anomalies dels motors. Lâobjectiu del treball és lâestudi del desgast originat en motors de combustió interna, majoritàriament, Dièsel de camions, automòbils i vaixells. Això, comprèn la captació de partícules en ferrografies, la seva observació i anàlisi en microscopi, la seva classificació, comparació i la detecció dâanomalies en els motors. Per altra banda, també sâaprofundirà en les tècniques dâanàlisi, la lubricació i manteniment dels motors i el nou disseny i validació dâun captador de partícules automatitzat

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Una marca de vehicles anuncia que, amb la venda dels seus models, es compromet a plantar prou arbres per fixar el CO2 que els cotxes trauran pel tub dâescapament. Malgrat el que digui la publicitat, el càlcul de lâabsorció del gas que fan els arbres resulta una qüestió no gens fàcil dâesbrinar

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Disseny dâun remolc de categoria O2,homologable per circular pe les vies públiques, i adaptat a les especificitats de les activitats de venda ambulant. El present projecte neix de la necessitat dels firaires i marxants disposar dâun espai de treball mòbil, el més similar possible als establiments fixes. El fet diferencial dâaquest vehicle consisteix en la seva capacitat per deixar la seva carrosseria al nivell del terra, facilitant el contacte entre client i venedor. El remolc està definit per un xassís format a partir de perfilaria dâacer i que consistirà la base del vehicle. Sobre el xassís es muntaran uns eixos abatibles accionats amb uns sistema hidràulic, i que permeten deixar la carrosseria al nivell del terra. Es fa la selecció també dels dispositius necessaris per a la seva homologació, com són els sistemes dâacoblament al vehicle tractor, de frenat i de direcció. La carrosseria muntada damunt del xassís consistirà en una caixa tancada construïda a partir de panells, perfils i tancaments comercials. El present projecte abasta el disseny i la selecció de components comercials, exceptuant els sistemes hidràulic i elèctric, dels que seân defineixen només les necessitats