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The effect of different road load implementation strategies on fuel economy of USPS step vansZia, Seiar Ahmad. January 2009 (has links)
Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xii, 92 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 79-81).
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The Use of Telemetry in Heavy Equipment Testing at Caterpillar Inc.Chapman, James E. 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Caterpillar has for many years used telemetry as a key component in the data acquisition
and analysis systems used to test and develop heavy equipment. The testing of
construction and mining equipment at Caterpillar presents several unique challenges, such
as the operating environment of the test machine, the large number of models in the
product line, the need to change test machines on a daily basis, and the need to test
machines at job sites throughout North America. These challenges have resulted in the
development of telemetry, data acquisition and data analysis systems that have been highly
customized to meet all of our requirements for construction equipment testing. This paper
describes the past history of telemetry use at Caterpillar, from early FM/FM systems to our
current PC/Unix based PCM/FM system, the criteria used to develop these systems, and
how our current telemetry system is being used today to help develop and test product.
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Modeling and simulation of flows over and through fibrous porous mediaLuminari, Nicola 19 March 2018 (has links) (PDF)
Any natural surface is in essence non-smooth, consisting of more or less regular roughness and/or mobile structures of different scales. From a fluid mechanics point of view, these natural surfaces offer better aerodynamic performances when they cover moving bodies, in terms of drag reduction, lift enhancement or control of boundary layer separation; this has been shown for boundary layer or wake flows around thick bodies. The numerical simulation of microscopic flows around "natural" surfaces is still out of reach today. Therefore, the goal of this thesis is to study the modeling of the apparent flow slip occurring on this kind of surfaces, modeled as a porous medium, applying Whitaker's volume averaging theory. This mathematical model makes it possible to capture details of the microstructure while preserving a satisfactory description of the physical phenomena which occur. The first chapter of this manuscript provides an overview of previous efforts to model these surfaces, detailing the most important results from the literature. The second chapter presents the mathematical derivation of the volume-averaged Navier-Stokes equations (VANS) in a porous medium. In the third chapter the flow stability at the interface between a free fluid and a porous medium, formed by a series of rigid cylinders, is studied. The presence of this porous layer is treated by including a drag term in the fluid equations. It is shown that the presence of this term reduces the rates of amplification of the Kelvin-Helmholtz instability over the whole range of wavenumbers, thus leading to an increase of the wavelength of the most amplified mode. In this same context, the difference between the isotropic model and a tensorial approach for the drag term has been evaluated, to determine the most consistent approach to study these flow instabilities. This has led to the conclusion that the model that uses the apparent permeability tensor is the most relevant one. In the following chapter, based on this last result, the apparent permeability tensor, based on over one hundred direct numerical simulations carried out over microscopic unit cells, has been identified for a three-dimensional porous medium consisting of rigid cylinders. In these configurations the tensor varies according to four parameters: the Reynolds number, the porosity and the direction of the average pressure gradient, defined by two Euler angles. This parameterization makes it possible to capture local three-dimensional effects. This database has been set up to create, based on a kriging-type approach, a behavioral metamodel for estimating all the components of the apparent permeability tensor. In the fifth chapter, simulations of the VANS equations are carried out on a macroscopic scale after the implementation of the metamodel, to get reasonable computing times. The validation of the macroscopic approach is performed on a closed cavity flow covered with a porous layer and a comparison with the results of a very accurate DNS, homogenized a posteriori, has shown a very good agreement and has demonstrated the relevance of the approach. The next step has been the study of the passive control of the separation of the flow past a hump which is placed on a porous wall, by the same macroscopic VANS approach. Finally, general conclusions and possible directions of research in the field are presented in the last chapter.
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Modeling and simulation of flows over and through fibrous porous media / Modélisation et simulation d'un écoulement autour d'une paroi poreuse et fibreuseLuminari, Nicola 19 March 2018 (has links)
Toute surface naturelle est par essence non lisse, elle est constituée de rugosités plus ou moins régulières et / ou de structures mobiles d’échelles variées. D’un point de vue mécanique des fluides, ces surfaces naturelles proposent des meilleures performances aérodynamiques en terme de réduction de traînée, d’augmentation de la portance ou de contrôle du décollement lorsqu’elles couvrent des corps en mouvement. Cela a été notament prouvé pour des écoulements de couches limites ou de sillage, autour de corps épais. La simulation numérique d’écoulements aux échelles microscopiques autour des surfaces « naturelles » demeure de nos jours encore hors de portée. En conséquence, la thèse a pour objet d’étudier la modélisation du glissement apparent de l’écoulement sur ce genre de surface, modélisée comme un milieu poreux, appliquant la théorie de la moyenne-volumique de Whitaker. Ce modèle mathématique permet globalement de représenter en moyenne les détails de la micro-structure de ses surfaces, tout en conservant une description satisfaisante des phénomènes physiques induits par l’écoulement. Le premier chapitre de ce manuscrit dresse un panorama des efforts antérieurs portant sur la modélisation de ces surfaces en précisant les résultats les plus importants issus de la littérature. Le deuxième chapitre présente la dérivation mathématique des équations de Navier- Stokes en moyenne volumique (VANS en anglais) dans un milieu poreux. Dans le troisième chapitre est étudiée la stabilité de l’écoulement à l’interface entre un fluide libre et un milieu poreux, constitué d'une série de cylindres rigides. La présence de cette couche poreuse est traitée par un terme de traînée dans les équations du fluide. On montre que l'ajout de ce terme réduit les taux d’amplification de l’instabilité de Kelvin-Helmholtz sur toute la gamme des nombre d’onde et ainsi augmente la longueur d’onde du mode le plus amplifié. Dans ce même contexte a été calculée la différence entre un modèle isotrope et une approche tensorielle pour le terme de traînée, afin de déterminer l’approche la plus consistante pour une étude de stabilité de ce type d’écoulement. Cela a mené à la conclusion que le modèle le plus pertinent est celui utilisant le tenseur de perméabilité apparent. Dans le chapitre suivant le tenseur de perméabilité apparent est identifié sur la base d’une centaine de simulations numériques directes, pour un milieu poreux tridimensionnel constitué de cylindres rigides, où le problème de fermeture est abordé par la méthode VANS. Dans ces configurations ce tenseur varie en fonction de quatre paramètres : le nombre de Reynolds, la porosité et l’orientation du gradient moyen de pression définie par deux angles d’Euler. Cette paramétrisation permet de capturer les effets tridimensionnels locaux. Cette base de données ainsi constituée a permis de créer, une approche de type kriging, un métamodèle comportemental pour estimer toutes les composantes du tenseur de perméabilité apparente. Dans le cinquième chapitre sont menées des simulations des équations VANS à l’échelle macroscopique après implémentation du méta-modèle qui autorise des temps de calcul raisonnables. La validation de l’approche à l’échelle macroscopique est effectuée sur un écoulement dans une cavité fermé couverte d’une couche poreuse et une comparaison avec les résultats d’un DNS très précise, homogénéisés a posteriori montre un très bon accord et démontre la pertinence de la démarche. L’étape suivante a consisté en l’étude du contrôle du décollement pour un écoulement autour d’une bosse poreuse par cette même approche VANS macroscopique. Enfin des conclusions générales et des directions de recherche possibles sont présentées dans le dernier chapitre. / Any natural surface is in essence non-smooth, consisting of more or less regular roughness and/or mobile structures of different scales. From a fluid mechanics point of view, these natural surfaces offer better aerodynamic performances when they cover moving bodies, in terms of drag reduction, lift enhancement or control of boundary layer separation; this has been shown for boundary layer or wake flows around thick bodies. The numerical simulation of microscopic flows around "natural" surfaces is still out of reach today. Therefore, the goal of this thesis is to study the modeling of the apparent flow slip occurring on this kind of surfaces, modeled as a porous medium, applying Whitaker's volume averaging theory. This mathematical model makes it possible to capture details of the microstructure while preserving a satisfactory description of the physical phenomena which occur. The first chapter of this manuscript provides an overview of previous efforts to model these surfaces, detailing the most important results from the literature. The second chapter presents the mathematical derivation of the volume-averaged Navier-Stokes equations (VANS) in a porous medium. In the third chapter the flow stability at the interface between a free fluid and a porous medium, formed by a series of rigid cylinders, is studied. The presence of this porous layer is treated by including a drag term in the fluid equations. It is shown that the presence of this term reduces the rates of amplification of the Kelvin-Helmholtz instability over the whole range of wavenumbers, thus leading to an increase of the wavelength of the most amplified mode. In this same context, the difference between the isotropic model and a tensorial approach for the drag term has been evaluated, to determine the most consistent approach to study these flow instabilities. This has led to the conclusion that the model that uses the apparent permeability tensor is the most relevant one. In the following chapter, based on this last result, the apparent permeability tensor, based on over one hundred direct numerical simulations carried out over microscopic unit cells, has been identified for a three-dimensional porous medium consisting of rigid cylinders. In these configurations the tensor varies according to four parameters: the Reynolds number, the porosity and the direction of the average pressure gradient, defined by two Euler angles. This parameterization makes it possible to capture local three-dimensional effects. This database has been set up to create, based on a kriging-type approach, a behavioral metamodel for estimating all the components of the apparent permeability tensor. In the fifth chapter, simulations of the VANS equations are carried out on a macroscopic scale after the implementation of the metamodel, to get reasonable computing times. The validation of the macroscopic approach is performed on a closed cavity flow covered with a porous layer and a comparison with the results of a very accurate DNS, homogenized a posteriori, has shown a very good agreement and has demonstrated the relevance of the approach. The next step has been the study of the passive control of the separation of the flow past a hump which is placed on a porous wall, by the same macroscopic VANS approach. Finally, general conclusions and possible directions of research in the field are presented in the last chapter.
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The Role of Informal Transit in New York City: A Case Study of Commuter Vans in Eastern QueensJanuary 2017 (has links)
abstract: Informal public transport is commonplace in the developing world, but the service exists in the United States as well, and is understudied. Often called "dollar vans", New York's commuter vans serve approximately 120,000 people every day (King and Goldwyn, 2014). While this is a tiny fraction of the New York transit rider population, it is comparable to the total number of commuters who ride transit in smaller cities such as Minneapolis/St Paul and Phoenix. The first part of this study reports on the use of commuter vans in Eastern Queens based on a combination of surveys and a ridership tally, all conducted in summer 2016. It answers four research questions: How many people ride the vans? Who rides the commuter vans? Why do they ride commuter vans? Do commuter vans complement or compete against formal transit? Commuter van ridership in Eastern Queens was approximately 55,000 with a high percentage of female ridership. Time and cost savings were the main factors influencing commuter van ridership. Possession of a MetroCard was shown to negatively affect the frequency of commuter van ridership. The results show evidence of commuter vans playing both a competing and complementary role to MTA bus and subway transit. The second part of this study presents a SWOT analysis results of commuter vans, and the policy implications. It answers 2 research questions: What are the main strengths, weaknesses, opportunities and threats of commuter vans in Eastern Queens? and How do the current policies, rules and regulations affect commuter van operation? The SWOT analysis results show that the commuter van industry is resilient, performs a necessary service, and, with small adjustments that will help reduce operating costs and loss of profits have a chance of thriving in Eastern Queens and the rest of New York City. The study also discusses the mismatch between policy and practice offering recommendations for improvement to ensure that commuter vans continue to serve residents of New York City. / Dissertation/Thesis / Masters Thesis Urban and Environmental Planning 2017
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Contribuição à comparação de meios para transporte urbano / Contribution to the comparison of transport modes.Costa, João Marcello Souza Pereira da 18 December 2001 (has links)
Esta dissertação relata resultados de ações de uma tentativa para mostrar que entrevistas a passageiros, escalas para comparação, e estudos sobre variáveis que caracterizam a qualidade de meios para transporte podem fornecer informações e dados que facilite a comparação entre as viagens urbanas de ônibus ou peruas. O processo usado foi identificar e quantificar variáveis que expressem medidas sobre características de qualidade em transporte de passageiros nas cidades. O manuseio e análise de dados adotou distribuições estatísticas e escalas para comparação. Os argumentos foram obtidos em um estudo de caso, o transporte de passageiros em Jaboatão dos Guararapes, estado de Pernambuco. Foram expostos os principais conceitos usados, em particular escalas" obtidas a partir de entrevistas a usuários; caracterização de estudo de caso e o manuseio dos dados. Os resultados podem contribuir para orientar decisões sobre ações que alterem o processo de competição entre os dois meios de transporte. / This dissertation reports the results obtained from actions of an attempt to show that opinions of passengers, scales for comparison, and studies on variables that characterize the quality of transportation modes can supply information and data to facilitate the comparison between the urban trips using buses or vans. The used process was to identify and to quantify variables to express measures on quality characteristics in passengers'' transport in the cities. The handling and analysis of data adopted statistical distributions and scales for comparison. The arguments were obtained in a case study, the passengers'' transport in Jaboatão dos Guararapes, state of Pernambuco, Brazil. There were exposed the main used concepts on scales" obtained starting from interviews to users; characterization of case study and the handling of the data. The conclusions can contribute to guide decisions about actions that alter the competition process among buses and vans.
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Contribuição à comparação de meios para transporte urbano / Contribution to the comparison of transport modes.João Marcello Souza Pereira da Costa 18 December 2001 (has links)
Esta dissertação relata resultados de ações de uma tentativa para mostrar que entrevistas a passageiros, escalas para comparação, e estudos sobre variáveis que caracterizam a qualidade de meios para transporte podem fornecer informações e dados que facilite a comparação entre as viagens urbanas de ônibus ou peruas. O processo usado foi identificar e quantificar variáveis que expressem medidas sobre características de qualidade em transporte de passageiros nas cidades. O manuseio e análise de dados adotou distribuições estatísticas e escalas para comparação. Os argumentos foram obtidos em um estudo de caso, o transporte de passageiros em Jaboatão dos Guararapes, estado de Pernambuco. Foram expostos os principais conceitos usados, em particular escalas obtidas a partir de entrevistas a usuários; caracterização de estudo de caso e o manuseio dos dados. Os resultados podem contribuir para orientar decisões sobre ações que alterem o processo de competição entre os dois meios de transporte. / This dissertation reports the results obtained from actions of an attempt to show that opinions of passengers, scales for comparison, and studies on variables that characterize the quality of transportation modes can supply information and data to facilitate the comparison between the urban trips using buses or vans. The used process was to identify and to quantify variables to express measures on quality characteristics in passengers'' transport in the cities. The handling and analysis of data adopted statistical distributions and scales for comparison. The arguments were obtained in a case study, the passengers'' transport in Jaboatão dos Guararapes, state of Pernambuco, Brazil. There were exposed the main used concepts on scales obtained starting from interviews to users; characterization of case study and the handling of the data. The conclusions can contribute to guide decisions about actions that alter the competition process among buses and vans.
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Vans Warped Tour’s boys club: An analysis of representations of women in alternative musicWolwacz Heinz, Natasha 07 December 2018 (has links)
No description available.
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EDI för små till medelstora företagSenad, Alicic January 2002 (has links)
<p>Handel mellan företag sker traditionellt via manuella rutiner. Exempelvis görs beställningar ofta med hjälp av telefon eller post vilket gör att tiden för att genomföra en affär väldigt lång. Electronic Data Interchange (EDI) är en teknik som låter företag göra affärer på ett elektroniskt och mer eller mindre automatiserat sätt vilket gör att tiden för att genomföra en affär minskar. EDI har använts i många år men då mest av stora företag som har tillräckliga resurser för att införa EDI-system och för att upprätta erforderliga kommunikationslänkar. Mindre företag har oftast inte de resurser som krävs för detta och blir således utan effektivare handelsrutiner. XML har fått uppmärksamhet som ett dokumentformat för strukturerade dokument vilket de dokument som överförs via EDI är ett exempel på. Value Added Networks (VAN) är ett företag som fungerar som en mellanlänk mellan parter och erbjuder olika tjänster som exempelvis konverteringar mellan olika företags standarder som bygger upp EDI-dokumenten. Detta gör att kommunikationen mellan parter blir dyr och oftast en orsak till att mindre företag inte inför EDI. Internet är idag ett utbrett och billigt kommunikationssätt vilket öppnar vägar för mindre företag att kunna kommunicera elektroniskt med andra företag. Vidare är XMLs naturliga koppling till webben en fördel eftersom dokument skapade i XML kan läsas i en vanlig webläsare. Denna rapport kommer därför försöka besvara frågan om XML/EDI är den bättre lösningen för små till medelstora företag jämfört med traditionell EDI. För att besvara frågan gjordes en undersökning som resulterade i faktorer som påverkar valet av EDI-införande</p>
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EDI för små till medelstora företagSenad, Alicic January 2002 (has links)
Handel mellan företag sker traditionellt via manuella rutiner. Exempelvis görs beställningar ofta med hjälp av telefon eller post vilket gör att tiden för att genomföra en affär väldigt lång. Electronic Data Interchange (EDI) är en teknik som låter företag göra affärer på ett elektroniskt och mer eller mindre automatiserat sätt vilket gör att tiden för att genomföra en affär minskar. EDI har använts i många år men då mest av stora företag som har tillräckliga resurser för att införa EDI-system och för att upprätta erforderliga kommunikationslänkar. Mindre företag har oftast inte de resurser som krävs för detta och blir således utan effektivare handelsrutiner. XML har fått uppmärksamhet som ett dokumentformat för strukturerade dokument vilket de dokument som överförs via EDI är ett exempel på. Value Added Networks (VAN) är ett företag som fungerar som en mellanlänk mellan parter och erbjuder olika tjänster som exempelvis konverteringar mellan olika företags standarder som bygger upp EDI-dokumenten. Detta gör att kommunikationen mellan parter blir dyr och oftast en orsak till att mindre företag inte inför EDI. Internet är idag ett utbrett och billigt kommunikationssätt vilket öppnar vägar för mindre företag att kunna kommunicera elektroniskt med andra företag. Vidare är XMLs naturliga koppling till webben en fördel eftersom dokument skapade i XML kan läsas i en vanlig webläsare. Denna rapport kommer därför försöka besvara frågan om XML/EDI är den bättre lösningen för små till medelstora företag jämfört med traditionell EDI. För att besvara frågan gjordes en undersökning som resulterade i faktorer som påverkar valet av EDI-införande
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