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Amplificador de Instrumentação em Modo Corrente com entrada e saída Rail-to-Rail / Current Mode Instrumentation Amplifier with Rail-to-Rail Input and OutputVieira, Filipe Costa Beber 05 January 2009 (has links)
This dissertation is aimed at the development of a current mode instrumentation amplifier (CMIA) with a high common mode input range. This characteristic is obtained due
to the rail-to-rail operational amplifiers (opamps). These opamps are built with rail-to-rail differential amplifiers as input stages, and with cascode-based output stages, which are able to copy its current by adding identical branches and connecting their gates without the voltage
degradation as the known CMIA topologies. The main contribution of this work is the development of a rail-to-rail current mode instrumentation amplifier, analyzing the pros and cons of this topology. The functionality of the proposed topology is shown through measured results of a manufactured integrated circuit. This first prototype, although it was operated in a large input common mode range, presented insufficient values of CMRR (Common Mode
Rejection Ratio) and VOS (Offset voltage). These two characteristics were studied and modeled, the instrumentation amplifier was re-designed, and simulated results demonstrate important improvements. / Esta dissertação tem como objetivo o desenvolvimento de um amplificador de instrumentação em modo corrente com uma ampla faixa de entrada em modo comum. Esta característica é obtida graças ao emprego de estágios de amplificação rail-to-rail na entrada e a geração do sinal de saída através do espelhamento da corrente diretamente dos gates dos
transistores do estágio ao invés da alternativa clássica, onde espelhos são ligados em série e degradam a excursão do sinal de saída. Com esta proposta, é possível a implementação de
ampops com entrada e saída rail-to-rail. A principal contribuição deste trabalho é analisar as vantagens e desvantagens da utilização destas soluções na implementação de um amplificador de instrumentação com entrada rail-to-rail. A funcionalidade da topologia proposta é demonstrada através dos resultados medidos de um circuito integrado fabricado. Este primeiro protótipo, apesar do bom funcionamento em toda a faixa de entrada em modo comum, apresentou valores insatisfatórios de CMRR (Common Mode Rejection Ratio) e de VOS (Tensão de offset), o que levou a um aprofundamento no estudo e modelagem destas características. A partir disto, o circuito foi re-projetado e os resultados de simulação
demonstram melhorias bastante significativas em suas características.
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Impacts of Transportation Investment on Real Property Values: An Analysis with Spatial Hedonic Price ModelsJanuary 2016 (has links)
abstract: Transportation infrastructure in urban areas has significant impacts on socio-economic activities, land use, and real property values. This dissertation proposes a more comprehensive theory of the positive and negative relationships between property values and transportation investments that distinguishes different effects by mode (rail vs. road), by network component (nodes vs. links), and by distance from them. It hypothesizes that transportation investment generates improvement in accessibility that accrue only to the nodes such as highway exits and light rail stations. Simultaneously, it tests the hypothesis that both transport nodes and links emanate short-distance negative nuisance effects due to disamenities such as traffic and noise. It also tests the hypothesis that nodes of both modes generate a net effect combining accessibility and disamenities. For highways, the configuration at grade or above/below ground is also tested. In addition, this dissertation hypothesizes that the condition of road pavement may have an impact on residential property values adjacent to the road segments. As pavement condition improves, value of properties adjacent to a road are hypothesized to increase as well. A multiple-distance-bands approach is used to capture distance decay of amenities and disamenities from nodes and links; and pavement condition index (PCI) is used to test the relationship between road condition and residential property values. The hypotheses are tested using spatial hedonic models that are specific to each of residential and commercial property market. Results confirm that proximity to transport nodes are associated positively with both residential and commercial property values. As a function of distance from highway exits and light rail transit (LRT) stations, the distance-band coefficients form a conventional distance decay curve. However, contrary to our hypotheses, no net effect is evident. The accessibility effect for highway exits extends farther than for LRT stations in residential model as expected. The highway configuration effect on residential home values confirms that below-grade highways have relatively positive impacts on nearby houses compared to those at ground level or above. Lastly, results for the relationship between pavement condition and residential home values show that there is no significant effect between them.
Some differences in the effect of infrastructure on property values emerge between residential and commercial markets. In the commercial models, the accessibility effect for highway exits extends less than for LRT stations. Though coefficients for short distances (within 300m) from highways and LRT links were expected to be negative in both residential and commercial models, only commercial models show a significant negative relationship. Different effects by mode, network component, and distance on commercial submarkets (i.e., industrial, office, retail and service properties) are tested as well and the results vary based on types of submarket.
Consequently, findings of three individual paper confirm that transportation investments mostly have significant impacts on real-estate properties either in a positive or negative direction in accordance with the transport mode, network component, and distance, though effects for some conditions (e.g., proximity to links of highway and light rail, and pavement quality) do not significantly change home values. Results can be used for city authorities and planners for funding mechanisms of transport infrastructure or validity of investments as well as private developers for maximizing development profits or for locating developments. / Dissertation/Thesis / Doctoral Dissertation Geography 2016
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A Study on Investment and Financing Model of Urban Rail ——With Case Study on Metro Rail Transit in city A, ChinaJanuary 2018 (has links)
abstract: As an alternative to the traditional public transportation system, (urban) rail transit has many advantages such as large capacity, fast speed, tight schedule, safety and comfort, and punctuality, , and has gradually become a top choice of many cities in countering environmental pollution and optimizing traffic quality. At the same time, we must also see that huge amounts of capital are required for the construction of rail transit. The traditional reliance on government investment clearly has its own limitations. The investment not only has a long cost-recovery cycle and a low rate of return, but also hardly attracts investments from the private sector. Therefore, when the government vigorously promotes the construction of a rail transit system, it is generally faced with problems such as a large funding gap and an overall financial loss. Therefore, how to establish a reasonable and efficient mode of investment and financing and further broaden the financing channels for rail transit projects is of great practical significance for improving the profitability of rail transit enterprises and realizing the sustainable development of rail transit. This thesis attempts to study the issue, in general, and further exmines a detailed case study of metro rail transit in a Chinsese city (city A), in particular.
The thesis first studies the concept and attributes of urban rail transit, and analyzes four modes and corresponding cases of urban rail transit investment and financing., It then discusses the characteristics of investment and financing of urban rail transit projects and the concept of investment and financing. Moreover, this thesis focuses on the current situation, characteristics and challenges of city A’s rail transit construction,. More specifically, it takes an in-depth look at the financial planning, investment and financing planning and the investment and financing channels products. The study innovatively puts forward three models, namely, PPP, TOD, ABS of rail transit investment and financing products. Based on the AHP decision-making method, the study shows PPP as the optimal integrated choice for city A. Finally, based on the core issues of the domestic urban rail transit project investment and financing, this thesis analyzes the rationality of the PPP model thoroughly and comes up with some managerial and policy suggestions on how to further optimize the investment and financing of the urban rail transit construction from the perspectives of the government management and the rail transit enterprises / Dissertation/Thesis / Doctoral Dissertation Business Administration 2018
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Alignment between business and IT strategies : a case study at a transport organisationConstance, Leroy David William January 2011 (has links)
Thesis (MTech (Information Technology))--Cape Peninsula University of Technology, 2011. / For almost three decades practitioners, academics, consultants, and research organisations
have identified 'attaining alignment between IT and business' (Luttman & Kempaiah, 2007),
as a pervasive problem. Despite the wide acceptance of the term "strategic alignment", there
was no consensus on how to achieve alignment. The research philosophy was of an
interpretive study and an inductive research approach was used. The research strategy was
by means of a case study, namely PRASA Western Cape, a business unit of Passenger Rail
Agency of South Africa (PRASA). The time horizon for this research was cross sectional. For
the data collection a semi-structured interview, supported by secondary data from the
business plan and annual report, was used. The research problem was "PRASA has
dysfunctional and fragmented institutional arrangements, resulting in misalignment between
business and IT". The primary research question to address this problem was "How can
PRASA manage strategic alignment between business and IT?" The aim of this research was to understand why the misalignment between business and IT
strategies exists at PRASA. A further aim was to propose a guideline to manage alignment
between business and IT strategies with the intention of overcoming the fragmented and
dysfunctional institutional arrangements. To address resolving the research problem three
theoretical models were used. The strategic alignment model was used to ascertain the
strategic perspective of PRASA as well as to identify the external strategic fit and internal
functional integration of an organisation. The second model used was the strategic alignment
maturity model. This model was used to identify the alignment maturity of the business/IT
strategies. The final model used was the balanced scorecard. Alignment is one of the best
practices recommended by the balanced scorecard, and it recommends aligning all to the
strategy of the company. The reason for using the balanced scorecard was that the company
currently uses this tool to manage performance. The research finding concluded that PRASA had the strategic execution alignment
perspective - business strategy dictates the IT strategy. The overall strategic alignment
maturity of the organisation was found to be in initial process. The balanced scorecard
methodology was known by all, yet few knew what the performance measures for the
organisation was for the year. The triangulated conclusion was that strategic alignment
between business and IT was a problem at PRASA. The recommendation was that the
organisation conducts three surveys firstly to identify its strategic choice, secondly to identify
the strategic alignment maturity and lastly to do a balanced scorecard best practice survey.
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Efeito do biodiesel no bico injetor e na emiss?o de material particulado em motor do ciclo dieselOliveira Filho, Manoel Fernandes de 13 May 2016 (has links)
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Previous issue date: 2016-05-13 / Bico injetor ? um importante componente do sistema de inje??o de um motor diesel respons?vel pela atomiza??o do combust?vel, por uma combust?o eficaz e uma baixa emiss?o de poluentes, a qual afeta diretamente o meio ambiente e o sistema cardiovascular humano. Os padr?es lim?trofes de emiss?es veiculares definidos pela legisla??o ambiental s?o crescentemente rigorosos, como o PROCONVE P7, no Brasil e a Euro 6, na Uni?o Europ?ia e restringem o tamanho do material particulado e NOx. O objetivo desta Tese foi investigar e compreender os mecanismos de desgaste de materiais fr?geis e d?cteis que se submetem ? a??o de um atomizador do tipo Common Rail, eros?o, cavita??o, ader?ncia, ades?o e corros?o. Desenvolveu-se um m?todo sistem?tico para avaliar biocombust?veis diesel, com aditivos ou obtido em postos, o seu processo de atomiza??o e sua intera??o com dois materiais estruturais, um quimicamente ativo, cobre eletrol?tico e um quimicamente inerte, vidro de ?xido de sil?cio. Um dispositivo equipado com uma c?mara de atomiza??o de alta press?o (HPSC), um dispositivo de ensaio de bico injetor e uma c?mera CCD foram usados na avalia??o do processo de atomiza??o. Nesta, foram ensaiados quatro fluidos: Ultrasene (fluido padr?o da m?quina TM 507); B6 aditivado com tensoativos; B6 com tensoativos e ?gua e B6 com tensoativos, ?gua e glicerina. Uma bancada dinamom?trica foi utilizada nos ensaios dos motores estacion?rio diesel monocil?ndrico, marca Branco BD 5.0, quatro tempos, de 5 cv funcionando com os combust?veis supracitados. Ao final de 150 horas de ensaio de cada combust?vel, o motor foi desmontado, inspecionado visualmente e feito um recondicionamento completo (incluindo bico injetor). O material particulado resultante da combust?o foi coletado por uma c?psula de coleta de gases da combust?o, desenvolvido pelo Grupo de Estudos de Tribologia e Integridade Estrutural (GET/UFRN). T?cnicas de an?lises por microscopia eletr?nica de varredura (MEV) e espectroscopia por energia dispersiva (EDS) foram usadas para avaliar os danos resultantes nos materiais submetidos ? atomiza??o e aos materiais particulados resultantes da combust?o do motor diesel BD 5.0 ap?s 20 e 150 horas. Para cada fluido ensaiado foi utilizado um bico injetor novo e os jatos atomizados por cada bico (novo e ap?s ensaios) foram filmados com c?mera CCD (resolu??o de 10 kfps). Posteriormente esses bicos foram analisados por MEV e EDS. Observaram-se part?culas met?licas com ?reas entre 0,5 e 50,0 ?m2. Evid?ncias de desgaste por ader?ncia, ades?o, corros?o, eros?o e cavita??o foram observadas no bico injetor, devido ao processo de atomiza??o dos fluidos. / A nozzle is a very important component of a diesel engine injection system. It is responsible for the atomization of the fuel for efficient combustion and low pollutant emissions levels, which directly affects the environment and the human cardiovascular system. The standards of vehicle emissions set by the environmental legislation are increasingly stringent, as PROCONVE P7 in Brazil and Euro 6, in the European Union. They restrict the size of the particulate material and NOx emissions levels. The main objective of this thesis is to investigate and understand the wear mechanisms of brittle and ductile materials which undergo the action of an atomizer type common rail, erosion, cavitation, adherence, adhesion, and corrosion. A systematic method was developed for evaluating diesel biofuels with additives or obtained in gas stations, its process of atomization and its interaction with two structural materials: a chemically active, electrolytic copper, and a chemically inert, silicon oxide glass. A test rig equipped with a high-pressure atomizing chamber (HPSC), a carrier device for ductile and brittle materials and a CCD camera were used to evaluate the atomization process. In this test rig there were tested three fluids: Ultrasene (standard fluid of the fluid nozzle testing machine TM 507), B6, B6 additivated with surfactants plus water and additivated B6 with surfactants, water and glycerin. A dynamometer test rig was used for testing a stationary diesel single cylinder engine, brand Branco, model BD5.0, four-stroke, 5 cv diesel, with the aforementioned fuels. In the end of 150 hours of each test fuel, the engine was disassembled, visually inspected and its main parts were replaced - piston, piston rings, pin, connecting rod, bearings, valves, seals, gaskets and the nozzle repair were replaced. The particulate matter coming from the combustion process, was collected by a device developed in the Tribology Study Group and Structural Integrity (GET-UFRN). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques were used to assess the damage resulting from the materials submitted to atomization and the particulate matter from the exhaust of combustion after 20 and 150 hours. Each fluid was atomized by a new nozzle and the spray atomized by each nozzle (the new one and after testing) was recorded using a CCD camera in a 10 kfps resolution. Posteriorly, those nozzles were analyzed by SEM and EDS. It was observed metal particles ranging in size from 0.5 to 50.0 ?m2. Evidences of wear by adherence, adhesion, corrosion, erosion and cavitation were observed on inject nozzle because the fuel atomization processes.
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Estudio numérico de la propagación de ondas guiadas en rieles ferroviariosIdzi, Javier Luis January 2017 (has links)
In recent decades techniques related to the measurement of elastic waves have advanced significantly. It is now possible with relatively inexpensive equipment to record amplitudes and frequency bands that were unthinkable two decades ago. This has led to the development of theoretical topics which application was questionable until not long ago, to profit from new technological potential in obtaining more and better experimental information. In this context the study of the propagation of guided waves in solids is presented as a knowledge that allows to detect damage with efficiency and economy in a number of structures in which at least one dimension is much larger than the other two. This is the case for rails, tubulations and pressure vessels among others. In this work, guided waves propagation characteristics are studied, first in a prismatic bar and then within the geometry of a rail. In both cases, dispersion curves were computed according two different work methodologies, first using an axisymmetric model and then corroborated with a model of periodic conditions. Finally propagation of a Tone-Burst waves were simulated on the analyzed geometries, leading to the discussion of how the waves scatter along its propagation. The results obtained were the dispersion curves of both sections. / En las últimas décadas técnicas relacionadas con la medición de ondas elásticas han avanzado sensiblemente. Actualmente, con equipamientos relativamente económicos es posible registrar amplitudes y franjas de frecuencia que eran impensables dos décadas atrás. Este hecho ha motivado que tópicos teóricos que hasta hace un tiempo tenían una aplicación cuestionable tengan que ser desarrollados para poder aprovechar las nuevas potencialidades tecnológicas en la obtención de mayor y mejor información experimental. En este contexto, el estudio de la propagación de ondas guiadas en sólidos se presenta como un conocimiento que posibilita detectar daño con eficiencia y economía en una serie de estructuras en las cuales por lo menos una dimensión es mucho mayor que las otras dos. Es el caso de estructuras tubulares, rieles o recipientes sometidos a presión entre otras. En el presente trabajo se estudian las características de propagación de ondas guiadas primeramente una barra rectangular y posteriormente en la geometría de un riel. En ambos casos, fueron calculadas las curvas de dispersión obtenidas con por dos metodologías de trabajo por elementos finitos, la primer metodología fue emplear un cálculo aplicando un modelo axisimétrico, y luego corroborado con un modelo de condiciones periódicas y posteriormente fue simulada la propagación de una onda tipo Toneburst sobre las geometrías analizadas discutiendo cómo dicha onda se dispersa durante su propagación. Los resultados obtenidos fueron las curvas de dispersión de ambas secciones.
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Analýza dopravních sítí a jejich výhodnost pro podnikatele / Analysis of traffic networks and their konvenience for entrepreneursSTRNKA, Jan January 2009 (has links)
The thesis focuses on comparison of road and rail freight in the South Bohemia rogion. The subjects of comparison were the ČSAD Jihotrans and the CD Cargo companies. The thesis consists of three parts: 1. transport of commodity {--} raw wood (round timber) by CD Cargo, 2. regular (daily) transport by ČSAD Jihotrans, 3. transport of cars by both companies and treir comparison. The main criterions are: time, systém of transport ordering, price and additional services provided. The aim was to use the services of both companies and to compare them from the viewpoint of a customer. From the results of the practical part of the thesis and after overall comparison of all the criterions I can conclude that road freight is more advantageous for the customers. However, we should not leave out of consideration the potentials of both types of cargo transport. Rail freight is of key importance in high-volume international cargo transport with a high percentage share in the transport of cars as well as of other commodities. Rail freight also better corresponds to the high requirements of the society on a sensitive approach of the companies to enviroment.
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Návrh projektu rozvoje temné turistiky / The proposal of dark tourism development projectIŠOVÁ, Veronika January 2010 (has links)
Thesis is concerned with the proposal of dark tourism development project. The proposed project locates in Znojmo region. Znojmo region has a considerable potential to develop varied forms of tourism, where falls within also dark tourism. Thesis purpose introduces two ways: First, the feasibility study realizes the potential in Znojmo region. Second, the feasibility study constructs the competent product, which contributes to region development. The product of project presents a nature trail "Tour behind the iron curtain" in National park Podyjí. Market analysis and demand analysis were implemented in the feasibility study. Financial analysis of the project and total costs effectiveness were interpreted in other period. Lastly all aspects of hazard were explored in the project including a total evaluation for investment grant.
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Drinking and Driving and Public Transportation: A Test of the Routine Activity FrameworkJanuary 2014 (has links)
abstract: Driving under the influence (DUI) is a problem in American society that has received considerable attention over recent decades from local police agencies, lobby groups, and the news media. While punitive policies, administrative sanctions and aggressive media campaigns to deter drinking and driving have been used in the past, less conventional methods to restructure or modify the urban environment to discourage drunk driving have been underused. Explanations with regard to DUIs are policy driven more often than they are guided by criminological theory. The current study uses the routine activities perspective as a backdrop for assessing whether a relatively new mode of transportation - an urban light rail system - in a large metropolitan city in the Southwestern U.S. can alter behaviors of individuals who are likely to drive under the influence of alcohol. The study is based on a survey of undergraduate students from a large university that has several stops on the light rail system connecting multiple campuses. This thesis examines whether the light rail system has a greater effect on students whose routines activities (relatively unsupervised college youth with greater access to cars and bars) are more conducive to driving under the influence of alcohol. An additional purpose of the current study is to determine whether proximity to the light rail system is associated with students driving under the influence of alcohol, while controlling for other criminological factors / Dissertation/Thesis / M.S. Criminology and Criminal Justice 2014
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Desgastes em trilhos ferroviarios : um estudo teorico / Wear in railway tracks, a theoretical studySemprebone, Paula da Silva 12 July 2005 (has links)
Orientador: Cassio Eduardo Lima de Paiva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-06T06:46:08Z (GMT). No. of bitstreams: 1
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Previous issue date: 2005 / Resumo: O assunto a ser abordado nesta pesquisa refere-se ao componente da superestrutura ferroviária trilho, especificamente aos defeitos que nele se verificam em conseqüência de sua utilização como guia para o material rodante e transmissor de esforços decorrentes do movimento do veículo, e do desgaste do contato roda-trilho. A importância de se realizar este estudo fundamenta-se na necessidade de se conhecer detalhadamente os defeitos e o limite de desgaste do trilho, que permitem determinar sua vida útil, para que se possa evitar ao máximo sua substituição, devido ao alto custo envolvido, além da questão da segurança da via que, dependendo do defeito, pode ser comprometida. Para a realização do trabalho foi realizada uma pesquisa bibliográfica, objetivando reunir informações sobre o assunto e levantar dissertações existentes que buscam solucionar tais problemas. Busca-se, ainda, encontrar uma justificativa para o valor limite de desgaste adotado atualmente no meio ferroviário, que corresponde a 25% de perda em área do boleto do trilho, através de simulações do desgaste utilizando-se um modelo computacional, além de rotinas de cálculo que permitam verificar se esse parâme1rO é restrição do . ponto de vista do dimensionamento do trilho. Pretende-se, assim, a1ravés desta pesquisa proporcionar uma contribuição ao meio ferroviário, avaliando-se se o limite de desgaste adotado mos1ra-se adequado à realidade ferroviária / Abstract: The matters concerned in this research particularly refer to damages caused by stress while using tracks on permanent railways as guide and strain transmitter of the vehicles. Importance is attached to this study based on the need of understanding deep and in detail the faults and wear limits on the tracks, which allow determining its period of use, so that substitution may be avoided due to its high costs. Furthermore, the railway safety may be weaknessed depending on the sort of wear. This study has basis on a bibliographical research aiming to gather information and possible works on this field in order to solve the problems mentioned above, as well as finding proofs for the current wear rate accepted in the railway field, which is 25% of track area decrease, throughout wear simulations on a computer based model, besides calculations which allow stating whether this standard depends on the track size. This work claims to contribute to the railway field evaluating if the adopted wear rate meets our railway reality / Mestrado / Transportes / Mestre em Engenharia Civil
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