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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.
331

Passenger Rail and Development in Small Cities, Towns, and Rural Areas: 21st Century Transit in Holyoke, Massachusetts

Laidlaw, W. Scott 01 January 2012 (has links) (PDF)
The intent of this thesis is to explore the design challenges and opportunities presented by the reintroduction of passenger rail to a small economically challenged New England city. Central to my thesis is that the advent of more efficient transportation options is not, in itself, enough: the infrastructure built to support those options must provide users with a comfortable, safe, and welcoming experience. The architecture of the rail station is critical in influencing that behavior and moving our society toward greater energy efficiency. Holyoke is a small mill city in western Massachusetts whose fortunes peaked in the early twentieth century and today struggles with decaying buildings and infrastructure, high unemployment, and significant poverty. The city also has many strengths, including relatively inexpensive hydro-electric power, sturdy adaptable mill buildings, an excellent location, strong neighborhood and civic pride, and a rich history on which to build. The city’s boosters feel that it is ripe for a renaissance already being driven by industry, the creative economy, telecommuters escaping the region’s major cities, and tourism. This research component of this thesis will explore: Current and historical demographic, industrial, and commercial context of the city and its passenger rail service, including usage projections, connections with various parts of the city, and Transit Oriented Design implications The needs of the adjacent Flats neighborhood for basic services and community space; strategies for attracting more consistent use of the station throughout its hours of operation by meeting the neighborhood residents’ needs Potential requirements for a station’s future capacity and adaptability – it will consider strategies for creating a flexible and adaptable building so as to meet the needs of the station and city as it changes over time Precedents that include rail stations and public buildings – it will investigate strategies used by effective public buildings The design component of this thesis incorporates the above research in developing site and program plans with a specific focus on design strategies that address accessibility, wayfinding, relevant services, and creating a welcoming gateway into the residential, industrial, and commercial heart of the city.
332

Wheel Wear Simulation of the Light Rail Vehicle A32

Robla Sánchez, Ignacio January 2010 (has links)
During the last decade, a novel methodology for wheel wear simulation has been developed in Sweden. The practical objective of this simulation procedure is to provide an integratedengineering tool to support rail vehicle design with respect to wheel wear performance and detailed understanding of wheel-rail interaction. The tool is integrated in a vehicle dynamicssimulation environment.The wear calculation is based on a set of dynamic simulations, representing the vehicle, the network, and the operating conditions. The wheel profile evolution is simulated in an iterativeprocess by adding the contribution from each simulation case and updating the profile geometry.The method is being validated against measurements by selected pilot applications. To strengthen the confidence in simulation results the scope of application should be as wide aspossible in terms of vehicle classes. The purpose of this thesis work has been to try to extend the scope of validation of this method into the light rail area, simulating the light rail vehicleA32 operating in Stockholm commuter service on the line Tvärbanan.An exhaustive study of the wear theory and previous work on wear prediction has been necessary to understand the wear prediction method proposed by KTH. The dynamicbehaviour of rail vehicles has also been deeply studied in order to understand the factors affecting wear in the wheel-rail contact.The vehicle model has been validated against previous studies of this vehicle. Furthermore new elements have been included in the model in order to better simulate the real conditionsof the vehicle.Numerous tests have been carried out in order to calibrate the wear tool and find the settings which better match the real conditions of the vehicle.Wheel and rail wear as well as profile evolution measurements were available before this work and they are compared with those results obtained from the simulations carried out.The simulated wear at the tread and flange parts of the wheel match quite well the measurements. However, the results are not so good for the middle part, since themeasurements show quite evenly distributed wear along the profile while the results from simulations show higher difference between extremes and middle part. More tests would benecessary to obtain an optimal solution.
333

Response of beams resting on viscoelastically damped foundation to moving oscillators

Muscolino, G., Palmeri, Alessandro January 2006 (has links)
The response of beams resting on viscoelastically damped foundation under moving SDoF oscillators is scrutinized through a novel state-space formulation, in which a number of internal variables is introduced with the aim of representing the frequency-dependent behaviour of the viscoelastic foundation. A suitable single-step scheme is provided for the numerical integration of the equations of motion, and the Dimensional Analysis is applied in order to define the dimensionless combinations of the design parameters that rule the responses of beam and moving oscillator. The effects of boundary conditions, span length and number of modes of the beam, along with those of the mechanical properties of oscillator and foundation, are investigated in a new dimensionless form, and some interesting trends are highlighted. The inaccuracy associated with the use of effective values of stiffness and damping for the viscoelastic foundation, as usual in the present state-of-practice, is also quantified.
334

Train–Bridge Interaction : Literature Review and Parameter Screening

Arvidsson, Therese January 2014 (has links)
New railway lines are continuously being constructed and existing lines are upgraded. Hence, there is a need for research directed towards efficient design of the supporting structures. Increasingly advanced calculation methods can be motivated, especially in projects where huge savings can be obtained from verifying that existing structures can safely support increased axle loads and higher speeds. This thesis treats the dynamic response of bridges under freight and passenger train loads. The main focus is the idealisation of the train load and its implications for the evaluation of the vertical bridge deck acceleration. To ensure the running safety of train traffic at high speeds the European design codes set a limit on the vertical bridge deck acceleration. By considering the train–bridge interaction, that is, to model the train as rigid bodies on suspension units instead of constant moving forces, a reduction in bridge response can be obtained. The amount of reduction in bridge deck acceleration is typically between 5 and 20% for bridges with a span up to 30 m. The reduction can be higher for certain train–bridge systems and can be important also for bridge spans over 30 m. This thesis aims at clarifying for which system parameter combinations the effect of train–bridge interaction is important. To this end, a thorough literature survey has been performed on studies in train–track–bridge dynamics. The governing parameters in 2D train–bridge systems have been further studied through a parameter screening procedure. The two-level factorial methodology was applied to study the effect of parameter variations as well as the joint effect from simultaneous changes in several parameters. The effect of the choice of load model was thus set in relation to the effect of other parameter variations. The results show that resonance can arise from freight train traffic within realistic speed ranges (&lt; 150 km/h). At these resonance peaks, the reduction in bridge response from a train–bridge interaction model can be considerable. From the screening of key parameters it can furthermore be concluded that the amount of reduction obtained with a train–bridge interaction model depends on several system parameters, both for freight and passenger train loads. In line with the European design code’s guidelines for dynamic assessment of bridges under passenger trains an additional amount of damping can be introduced as a simplified way of taking into account the reduction from train–bridge interaction. The amount of additional damping is today given as function of solely the bridge span length, which is a rough simplification. The work presented in this thesis supports the need for a refined definition of the additional damping. / Nya järnvägslinjer byggs kontinuerligt och befintliga linjer uppgraderas. Det finns därför ett behov av forskning inriktad på effektiv design av de bärande konstruktionerna. Alltmer avancerade beräkningsmetoder kan vara motiverade, särskilt i projekt där stora besparingar kan erhållas från att verifiera att befintliga konstruktioner kan bära ökade axellaster och högre hastigheter. Föreliggande avhandling behandlar broars dynamiska respons under belastning av gods- och passagerartåg. Huvudfokus är att studera modelleringsalternativ för tåglasten och vilka konsekvenser de har för utvärderingen av brobanans vertikala acceleration. För att garantera trafiksäkerhet vid höga tåghastigheter definierar de europeiska normerna en maximalt tillåten vertikal acceleration i brobanan. Genom att beakta tåg-bro-interaktion, där tågkomponenterna modelleras som avfjädrade stela kroppar istället för konstanta punktlaster, kan en minskning av brons respons erhållas. Reduktionen av brobanans acceleration är typiskt mellan 5 och 20% för broar med en spännvidd på upp till 30 m. Minskningen kan vara högre för vissa tåg-brosystem och kan vara viktigt också för spännvidder över 30 m. Denna avhandling syftar till att klargöra för vilka kombinationer av tåg-broparametrar effekten av tåg-bro-interaktion är viktig. I detta syfte har en omfattande litteraturstudie genomförts inom området tåg-spår-brodynamik. De styrande parametrarna i 2D tåg-brosystem har studerats vidare i en parameterstudie. Två-nivå faktorförsök har tillämpats för att studera effekten av parametervariationer samt den ytterligare effekten av samtidiga förändringar i flera parametrar. Effekten av valet av lastmodell sattes därmed i relation till effekten av andra parametervariationer. Resultaten visar att resonans kan uppstå från godstrafik inom ett realistiskt hastighetsintervall (&lt; 150 km/h). Vid dessa resonanstoppar kan en betydande minskning av broresponsen erhållas med en tåg-bro-interaktionsmodell. Från studien av nyckelparametrar kan man vidare dra slutsatsen att reduktionen som erhålls med en tåg-bro-interaktionsmodell beror på flera systemparametrar, både för gods- och passargerartåg. Enligt de europeiska normernas rekommendationer för dynamisk kontroll av broar för passagerartrafik kan en ökad brodämpning introduceras som ett förenklat sätt att ta hänsyn till minskningen från tåg-bro-interaktion. Mängden tilläggsdämpning anges idag som en funktion av enbart brons spännvidd, vilket är en grov förenkling. Det arbete som presenteras i denna avhandling visar på behovet av en förbättrad definition av tilläggsdämpningen. / <p>QC 20140429</p>
335

Cost-efficient method forlifetime extension ofinterconnectedcomputer-based systems / Kostnadseffektiv metod för livstidsförlängning avsammanlänkade datorbaserade system

Holmberg, Wilhelm January 2021 (has links)
Lifetime and obsolescence of components for computer-based systems poses issues for continued usage and maintenance of the systems. This thesis investigates possible alternatives for lifetime extension of a train identification system used in Stockholm Metro. Research of other train identification systems available on the market were made to enable a cost comparison between lifetime extension and system replacement. Methods for extending lifetime of computer-based system, where components are obsolete, were investigated. Since most system documentation was inaccessible a reverse- engineering approach was chosen. Through usage of electrical schematics acquired and open-source hardware descriptions a hardware emulator was developed, which is directly compatible with the existing hardware. The total amount of resources used indicates it is possible to extend the systems lifetime at a low cost, as compared to the cost of system replacement. / Livslängd och åldrande av komponenter för datorbaserade system utgör problem för fortsatt användande och underhåll av systemen. Den här avhandlingen undersöker möjliga alternativ för livstidsförlängning av ett tågidentifieringssystem som används i Stockholms tunnelbana. Efterforskningar av andra tågidentifieringssystem tillgängliga på marknaden genomfördes för att möjliggöra en kostnadsjämförelse mellan livstidsförlängning och systemutbyte. Metoder för förlängning av livslängd av datorbaserade system, där komponenter är föråldrade, undersöktes. Då stora delar av systemdokumentationen inte var tillgänglig valdes baklängesutveckling som strategi. Genom användande av förvärvade elscheman och öppen-källkod hårdvarubeskrivningar kunde en hårdvaruemulator utvecklas, vilken är direkt kompatibel med befintlig hårdvara. Den totala resursanvändningen indikerar att det är möjligt att förlänga systemets livslängd till en låg kostnad, jämfört med kostnaden för ett systembyte.
336

Design, Validation, and Optimization of a Rear Sub-frame with Electric Powertrain Integration

Walters, David Michael 18 September 2015 (has links)
No description available.
337

Developing, Demonstrating, and Validating a Vehicle Test Bed to Extend the Capabilities of a Chassis Dynamometer Test System

Murphy, Robert T. 29 December 2008 (has links)
No description available.
338

Portrait du clown en personnage de roman : A partir de Gavroche (Les misérables), Kenwell et Cox (Le train 17) et les frères Zemganno (Les frères Zemganno)

Gagnon, Evelyne. January 2008 (has links)
No description available.
339

Redesign of linear drive unit for wheelchair lifts for trains

Meyer-Dietrich, Simon January 2024 (has links)
The UPL-300 is a fully electric wheelchair lift for trains. Many wheelchair lifts for trains exist on the market but the vast majority are driven by hydraulics. Electric drive prevents potential hydraulic fluid spills and negates the need for special disposal of the fluid. The aim of this project was to improve this lift because it struggled to compete on that market and no longer met industry standards. This project first identified which areas of the UPL-300 needed improving and then worked on two of these areas, the linear drive unit (LDU) which enables the lift to go up and down and the wall brace which connects the linear drive unit to the wall of a train car. The results were a design document for the wall brace and a new design for the LDU. The wall brace design document aimed to simplify and expedite the design process of the customer specific wall brace. The new LDU cut the cost for the lift significantly and fulfilled the requirements of modern standards. The design of the new LDU is easily scalable and has the potential to be used as a linear actuator in other products. The improvement analysis, together with the other work done in this project, laid a strong foundation for future work to improve the UPL-300 fully electric wheelchair lift for trains.
340

Wideband Propagation Measurement Results, Simulation Models, and Processing Techniques for a Sliding Correlator Measurement System

Newhall, William George 12 December 1997 (has links)
Radio wave propagation measurements provide a way to accurately and reliably characterize environments to assist in the development and optimization of wireless communication systems. As digital radio systems occupy wider bandwidths and use multipath signal combining to enhance quality of service, knowledge of time dispersion and the multipath structure of radio channels become increasingly important. The wideband measurement system presented herein provides a practical means to precisely measure the delays and strengths of individual multipath components which arrive at a radio receiver. Presented in this Thesis are fundamental theory, practical implementation, and simulation models for a sliding correlator measurement system. The sliding correlator technique is explained in detail and large-scale measurement survey is presented. Techniques for statistically quantifying the characteristics of propagation using the sliding correlator measurements are presented and compared. The development of simulations of the sliding correlator system is described, and simulation results are used to test conventional and newly developed post-processing algorithms. This Thesis presents a practical view of the sliding correlator measurement system, but its foundations are rooted in the theoretical results which are explained and derived herein. Propagation researchers and students in the wireless communication field may find this work and the cited references useful for continued study of wideband propagation measurements or for application of the sliding correlator system as a wideband measurement solution. / Master of Science

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