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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.
101

Energy storage solutions for electric bus fast charging stations : Cost optimization of grid connection and grid reinforcements

Andersson, Malin January 2017 (has links)
This study investigates the economic benefits of installing a lithium-ion battery storage (lithium iron phosphate, LFP and lithium titanate, LTO) at an electric bus fast charging station.  It is conducted on a potential electric bus system in the Swedish city Västerås, and based on the existing bus schedules and routes as well as the local distribution system. The size of the energy storage as well as the maximum power outtake from the grid is optimized in order to minimize the total annual cost of the connection. The assessment of the distribution system shows that implementing an electric bus system based on opportunity charging in Västerås does not cause over-capacity in the 10 kV grid during normal feeding mode. However, grid reinforcements might become necessary to guarantee potential backup feeding modes. Batteries are not a cost effective option to decrease grid owner investments in new transformers. However, battery energy storage have the possibility to decrease the annual cost of connecting a fast charging station to the low-voltage grid. The main advantage of the storage system is to decrease the fees to the grid owner. Of the studied batteries, LTO is the most cost effective solution because of its larger possible depth-of-discharge for a given cycle life. The most important characteristics, that determine if a fast charging station could benefit economically from an energy storage, is the bus frequency. The longer the time in between buses and the higher the power demand, the more advantageous is the energy storage.
102

Buses, But Not Spaces For All: Histories of Mass Resistance & Student Power on Public Transportation in Mexico & The United States

Thomas, Julia 01 January 2017 (has links)
Public spaces—particularly buses, which often carry a larger proportion of low-income to middle class individuals and people of color—serve as shared places for recreation, travel, and labor, and are theoretically created with the intention of being an “omnibus,” or a public resource for all. While buses have been the sites of intense state control and segregation across the world, they have also been places in which groups have organized bus boycotts, commandeered control of transportation, ridden across state lines, and taken over spaces that allow them to express power by occupying a significant area. Buses have become spaces of exchange and power for the people who have, in some cases, been marginalized by ruling private interests and institutionalized racism to ride in masses on particular routes. From the turn of twentieth century to 1968 in Mexico, the Civil Rights movement in the mid twentieth century United States, to the contemporary era in the U.S. and Mexico, public spaces have been historically reclaimed as key instruments in social movements. By analyzing these moments, this thesis explores the complex relations over power on buses for riders—university students in in Mexico, and African Americans in the U.S.—and show how they have been both key vehicles in mobilization and resistance against state oppression and the sites of targeted violence and racism.
103

Mercado multimodal de Rengo: renovación del rodoviario y mercado municipal

González Mora, Valesca January 2013 (has links)
Arquitecto / El Mercado Multimodal de Rengo, proyecto desarrollado para optar al título de Arquitecto de la Universidad de Chile, aborda la temática de los Sistemas de Asentamientos Humanos principalmente desde dos perspectivas: primero desde el Sistema de Transportes, ya que es fundamental para mantener la cohesión de la red mayor y es el que permite el desplazamiento de los diversos elementos componentes del sistema; y el segundo desde el sistema urbano-social, es decir, de los impactos que genera la arquitectura en el medio en que se inserta y de cómo en torno a ella se pueden desarrollar complejas redes de interacción social.
104

Jämförelse mellan olika biodrivmedel för den kollektiva busstrafiken i Gävleborgs län : Miljö- och potentialbedömning av biodiesel, biogas och eldrift

Nordin, Elin, Thiede, Emma January 2016 (has links)
Fossila drivmedel ger en negativ påverkan på miljö och klimat. Men frågan är om biodrivmedel är bättre. Det kan skilja stort mellan olika drivmedel beroende på vilken råvara och framställningsprocess som används. Syftet med studien är att göra en sammanställning av fördelar och nackdelar med olika fossilfria drivmedel som används och kan komma att användas i kollektivtrafiken i Gävleborgs län. I samråd med X-trafik, den regionala kollektivtrafikmyndigheten, har det framkommit att det främst är biodiesel (HVO - hydrogenerade vegetabiliska oljor), biogas och el som är intressanta att analysera. Rapporten kommer att redogöra hur användningen ser ut i andra delar av landet och i världen för att kunna anpassa kunskaperna till Gävleborgs län. I studien ingår även en granskning av produktionspotentialen för dessa drivmedel i länet. Det slutgiltiga resultatet av studien kommer att bidra till utvecklingen av en fossilfri fordonsflotta i regionen. Genom intervjuer med närproducenter av biogas (Gästrike Ekogas AB) och biodiesel (Colabitoil AB) samt med X-trafik inhämtades kunskap om hur produktionen ser ut i länet och vilka behov som finns. Detta tillsammans med en litteraturstudie gav resultatet. X-trafik har huvudansvaret för kollektivtrafiken och utför den genom entreprenörer som fått uppdragen genom upphandling. HVO har många fördelar mot andra dieselbränslen och kan tankas direkt i fordonen utan att dessa behöver modifieras. Dessutom görs den HVO som Colabitoil distribuerar och kommer börja producera på restavfall. En av X-trafiks entreprenörer har slutit ett avtal med Colabitoil vilket betyder att all fossil diesel som bussarna kör på idag kommer att bytas ut mot biodiesel. I Gävle stad kör bussarna på biogas och gasen produceras på avloppsreningsverket Duvbacken. Denna produktion täcker upp 60 % av behovet och resten är fossil gas. Med den nya anläggningen som Gästrike Ekogas håller på att bygga kommer behovet mer än väl täckas upp. Biogasen är även den gjord på restavfall. I den nya biogasanläggningen kommer de också få en utmärkt biogödsel fri från föroreningar, som kan KRAV-märkas och användas till odling för att ersätta konstgödsel. Elbussar är något som diskuteras av X-trafik och kan vara bra alternativ på vissa linjer dock är tekniken under utveckling fortfarande och investeringskostnaden är hög. Det finns potential att kollektivtrafiken i Gävleborgs län kan köra på 100 % miljövänligt, hållbara och närproducerade drivmedel inom en snar framtid. / The purpose of this study is to make a summary of the advantages and disadvantages of various non-fossil fuels that are used and can be used in public transport in the county. In consultation with X-trafik, it has emerged that it is mainly biodiesel (in the form of  HVO - hydrogenated vegetable oils), biogas and electricity that are interesting to analyse. The report will describe the use in other parts of the country and the world to adapt the knowledge to the county. The study also includes an investigation of the production potential of these fuels within the county. The final results of the study will contribute to the development of a fossil free fleet in the region. Through interviews with local producers of biogas (Gästrike Ekogas AB) and biodiesel (Colabitoil AB) and X-trafik information was collected about how the production is performed in the county and what the needs are. This, together with a literature review yielded the results. X-trafik has the main responsibility for the public transport and carries it out through contractors with assignments through procurement. HVO has many advantages compared to other diesel fuels and can be refueled directly in vehicles without modifications of these. Additionally, the HVO that Colabitoil distributes and will begin producing is made of residual waste. One of X-Trafik's contractors has signed a contract with Colabitoil which means that all fossil diesel the buses run on today will be replaced with biodiesel. In Gävle city the buses run on biogas and the gas is produced at the sewage treatment plant. This production covers 60% of the need and the rest is fossil gas. The new facility, which Gästrike Ekogas is building, will produce more than the public transport needs. Biogas is also made from residual waste. The new facility will also yield a by-product in the form of an excellent bio-fertilizer free of contaminants that can be KRAV labelled and used for cultivation to replace chemical fertilizers. Electric buses are something that is discussed, and may be a good option on certain routes, however, the technology is still under development and the investment cost is high. There is great potential that the public transport in the county can run on 100% eco-friendly, sustainable and locally produced fuels in the near future.
105

Investigação das falhas do sistema de acionamento de embreagem do tipo cilindro escravo concêntrico em veículos comerciais pesados sob as condições operacionais do mercado brasileiro. / Investigation of failures clutch drive system of concentric slave cylinder type in heavy commercial vehicles under operational conditions in Brazil.

Souza, Jairo de Lima 28 July 2006 (has links)
A evolução dos sistemas de transporte no modal rodoviário tem criado novas demandas operacionais devido à crescente concorrência e aumento da pressão para a redução de custos. Em face dessas novas demandas, muitas delas advindas da globalização, geraram uma mudança no perfil da frota de veículos comerciais pesados no mercado brasileiro. Frotas que anteriormente eram compostas por veículos comerciais pesados 4x2 (4 pontos de apoio no solo com tração em 2 pontos) operando com carretas de três eixos com capacidade de transporte de 45 toneladas, passaram a ser gradativamente substituídas por aquelas compostas por veículos comerciais pesados 6x2 (6 pontos de apoio no solo com tração em 2 pontos) com carretas do tipo bi-trem e rodo-trem com capacidade de transporte de 57 e 74 toneladas respectivamente. Esta mudança foi acompanhada pelo aumento da pressão do custo de aquisição dos veículos comerciais pesados, com isso, verificou-se que os principais frotistas brasileiros passaram a adaptar eixos de apoio nos veículos 4x2, aumentando assim as solicitações mecânicas impostas ao sistema de embreagem. Neste trabalho desenvolve-se, portanto, um estudo sobre as falhas ocorridas no sistema de acionamento de embreagem por cilindro escravo concêntrico no mercado brasileiro, avaliando-se a seleção de materiais empregados na construção do sistema através de ensaios químico-laboratoriais e testes de funcionalidade através de ensaios em condições reais de operação com veículos comerciais pesados devidamente instrumentados, mantendo o foco nos novos parâmetros operacionais impostos pelo novo perfil da composição tratora. Como resultado, apontam-se duas alternativas para a solução das falhas encontradas no mercado brasileiro: 1. Proposição de nova solução técnica construtiva para o sistema de acionamento da embreagem a fim de aumentar a robustez do componente de maior suscetibilidade às falhas. 2. Proposição de um modelo matemático para a predição do intervalo mínimo de manutenção para o sistema de acionamento da embreagem por cilindro escravo concêntrico. / The evolution of highway transportation of goods in the brazilian market has created new operation requirements due to the increased competition allied to the cost reduction demands. This new demands, most of them coming from globalization, have generated a significant change on the profile of heavy commercial vehicles. Fleets that were mainly composed of 4x2 tractors coupled to three wheeled semi-trailers with towing capacity of 45 tons, were in small steps exchanged by new compositions of tractors 6x2 coupled to bi-trains and road-trains with total towing capacity of 57 and 74 tons, respectively. This change have been followed by the new purchasing demands from fleet owners by lowering acquisition costs of new heavy commercial vehicles, as a consequence, most of 4x2 trucks have been adapted with tag-axles in order to increase towing capacity, which means increasing the stresses over the clutch system. On this research, a case study is developed about failures on clutch systems actuators by the concentric slave cylinder concept in the brazilian market. The research is developed by the evaluation of types of materials selected to the system components through chemical test and functionality tests carried on actual operation conditions on instrumented vehicles, keeping always the focus on the new operational demands imposed by the new profile of vehicle compositions (bi-trains and road-trains). As a final result, two alternatives are appointed to solve the failures in the brazilian market: 1. By the determination of the most failure susceptible component, it is possible to propose a mathematical and theoretical model to determine the minimum maintenance interval to the clutch actuation system by concentric slave cylinder concept. 2. Proposition of a new technical construction to the system in order to increase the robustness of the component most susceptible to the failures.
106

Development of computerised management information system for bus maintenance in Kowloon Motor Bus Co., (1933) Ltd.

January 1992 (has links)
by Sit Wing-Hang, Leung Chiu-Ping. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaf 80). / ACKNOWLEDGMENT --- p.1 / EXECUTIVE SUMMARY --- p.2 / Chapter 1. --- INTRODUCTION --- p.5 / Chapter 1.1 --- Company Background --- p.5 / Chapter 1.2 --- Project Objective --- p.8 / Chapter 1.3 --- Scope Of Work --- p.9 / Chapter 2. --- RESEARCH METHODOLOGY --- p.12 / Chapter 2.1 --- Interview --- p.12 / Chapter 2.2 --- Refer To Organisation In Similar Nature --- p.12 / Chapter 2.3 --- Field Observation --- p.13 / Chapter 3. --- PRESENT SITUATION AND PROBLEM AREAS -FINDINGS AND ANALYSIS --- p.14 / Chapter 3.1 --- Costing Accounting System --- p.14 / Chapter 3.2 --- Management Planning System --- p.18 / Chapter 3.3 --- Manpower Control System --- p.21 / Chapter 3.4 --- Stock Control System --- p.26 / Chapter 3.5 --- Vehicle And Major Component History Recording System --- p.29 / Chapter 4. --- SYSTEM DEVELOPMENT STRATEGY --- p.32 / Chapter 5. --- SYSTEM DESIGN --- p.37 / Chapter 5.1 --- Accounting System --- p.38 / Chapter 5.2 --- Management Planning System --- p.42 / Chapter 5.3 --- Manpower Planning System --- p.47 / Chapter 5.4 --- Stock Control System --- p.55 / Chapter 5.5 --- Vehicle And Major Component System --- p.57 / Chapter 6. --- HARDWARE DESIGN --- p.60 / Chapter 6.1 --- Hardware Configuration --- p.60 / Chapter 6.2 --- Interface With Existing Computer Facilities --- p.62 / Chapter 7. --- IMPLEMENTATION PLAN --- p.64 / Chapter 8. --- COST-EFFECTIVENESS ANALYSIS --- p.69 / Chapter 8.1 --- Cost Analysis --- p.69 / Chapter 8.2 --- Benefit Analysis --- p.70 / Chapter 9. --- CONCLUSION --- p.78 / BIBLIOGRAPHY --- p.80 / APPENDICES
107

Marketing public transit : bus transportation in a small city

Cosgrove, Barry Clement January 1981 (has links)
Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Includes bibliographical references. / by Barry Clement Cosgrove. / M.C.P.
108

The role of federal government in fostering technological change in public transportation : a case study of transbus

Azad, Bizhan January 1980 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 157-162. / by Bizhan Azad. / M.S.
109

Fortaleza de Ãnibus: Quebra-quebra, lock-out e liberaÃÃo na construÃÃo do serviÃo de transporte coletivo de passageiros entre 1945 e 1960 / Fortaleza Bus: Break-break, lock-out and release the construction of the transportation service of passengers between 1945 and 1960

Patricia Menezes 01 September 2009 (has links)
nÃo hà / Este trabalho pretende reconstruir o processo de formaÃÃo do sistema de transporte coletivo de passageiros realizado por Ãnibus em Fortaleza entre 1945 a 1960. O estudo compreende os anos posteriores à retirada de circulaÃÃo dos bondes elÃtricos da Cearà Light, no final do ano de 1947, assinalando as transformaÃÃes da cidade e as condiÃÃes da mobilidade pÃblica no decorrer dos anos de 1950. Num universo de ampliaÃÃo de territÃrios e de diversificaÃÃo das experiÃncias urbanas, a narrativa percorre a constituiÃÃo recÃproca dos grupos sociais ligados ao transporte, percorrendo seus discursos e suas prÃticas polÃticas nos conflitos que envolveram as tentativas de normalizaÃÃo do serviÃo. / This paper aims to rebuild the process of consolidation of public transportation system with buses in Fortaleza, from 1945 to 1960. It focus on the years after trolley cars stopped to circulate in Fortaleza, in the late days of 1947, highlighting the transformations in the city and the conditions of public mobility in the 1950âs. On a time of city growth and diversification of urban experiences, it shows the first days of social groups related to public transportation, with their methods in the struggle that happened with the attempts to normalize the service offered to the population of the city.
110

Investigação das falhas do sistema de acionamento de embreagem do tipo cilindro escravo concêntrico em veículos comerciais pesados sob as condições operacionais do mercado brasileiro. / Investigation of failures clutch drive system of concentric slave cylinder type in heavy commercial vehicles under operational conditions in Brazil.

Jairo de Lima Souza 28 July 2006 (has links)
A evolução dos sistemas de transporte no modal rodoviário tem criado novas demandas operacionais devido à crescente concorrência e aumento da pressão para a redução de custos. Em face dessas novas demandas, muitas delas advindas da globalização, geraram uma mudança no perfil da frota de veículos comerciais pesados no mercado brasileiro. Frotas que anteriormente eram compostas por veículos comerciais pesados 4x2 (4 pontos de apoio no solo com tração em 2 pontos) operando com carretas de três eixos com capacidade de transporte de 45 toneladas, passaram a ser gradativamente substituídas por aquelas compostas por veículos comerciais pesados 6x2 (6 pontos de apoio no solo com tração em 2 pontos) com carretas do tipo bi-trem e rodo-trem com capacidade de transporte de 57 e 74 toneladas respectivamente. Esta mudança foi acompanhada pelo aumento da pressão do custo de aquisição dos veículos comerciais pesados, com isso, verificou-se que os principais frotistas brasileiros passaram a adaptar eixos de apoio nos veículos 4x2, aumentando assim as solicitações mecânicas impostas ao sistema de embreagem. Neste trabalho desenvolve-se, portanto, um estudo sobre as falhas ocorridas no sistema de acionamento de embreagem por cilindro escravo concêntrico no mercado brasileiro, avaliando-se a seleção de materiais empregados na construção do sistema através de ensaios químico-laboratoriais e testes de funcionalidade através de ensaios em condições reais de operação com veículos comerciais pesados devidamente instrumentados, mantendo o foco nos novos parâmetros operacionais impostos pelo novo perfil da composição tratora. Como resultado, apontam-se duas alternativas para a solução das falhas encontradas no mercado brasileiro: 1. Proposição de nova solução técnica construtiva para o sistema de acionamento da embreagem a fim de aumentar a robustez do componente de maior suscetibilidade às falhas. 2. Proposição de um modelo matemático para a predição do intervalo mínimo de manutenção para o sistema de acionamento da embreagem por cilindro escravo concêntrico. / The evolution of highway transportation of goods in the brazilian market has created new operation requirements due to the increased competition allied to the cost reduction demands. This new demands, most of them coming from globalization, have generated a significant change on the profile of heavy commercial vehicles. Fleets that were mainly composed of 4x2 tractors coupled to three wheeled semi-trailers with towing capacity of 45 tons, were in small steps exchanged by new compositions of tractors 6x2 coupled to bi-trains and road-trains with total towing capacity of 57 and 74 tons, respectively. This change have been followed by the new purchasing demands from fleet owners by lowering acquisition costs of new heavy commercial vehicles, as a consequence, most of 4x2 trucks have been adapted with tag-axles in order to increase towing capacity, which means increasing the stresses over the clutch system. On this research, a case study is developed about failures on clutch systems actuators by the concentric slave cylinder concept in the brazilian market. The research is developed by the evaluation of types of materials selected to the system components through chemical test and functionality tests carried on actual operation conditions on instrumented vehicles, keeping always the focus on the new operational demands imposed by the new profile of vehicle compositions (bi-trains and road-trains). As a final result, two alternatives are appointed to solve the failures in the brazilian market: 1. By the determination of the most failure susceptible component, it is possible to propose a mathematical and theoretical model to determine the minimum maintenance interval to the clutch actuation system by concentric slave cylinder concept. 2. Proposition of a new technical construction to the system in order to increase the robustness of the component most susceptible to the failures.

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