Abstract

n economic analysis is made of vehicles powered by compressed natural gas (CNG), alcohol, and electric vehicles (EV's) as possible replacements for gasoline-powered vehicles. Advantages and disadvantages of vehicles powered by the various fuels are discussed and determinations of their suitability are made based on vehicle performance characteristics and fuel availability. CNG and EV's are determined to be viable alternatives based on current state-of-the-art technology. Alcohol is not retained as a viable alternative because of limited fuel availability. Models are presented for determining the total life cycle cost for gasoline, CNG, and EV's. A fleet of seventy-two vehicles at the Naval Postgraduate School is used as an example to compare the cost of each alternative. A linear program is used to determine the mix of gasoline, CNG, and electric vehicles that satisfy mission requirements for the least total fleet life cycle cost and to perform sensitivity analysis on the cost determinants. A generalized formulation is also presented to allow a vehicle fleet manager to use the methodology of this thesis as an aid to evaluating the potential of alternatively-fueled vehicles in different situations. http://archive.org/details/decisionmodelsfo00garr Lieutenant, United States Navy Approved for public release; distribution is unlimited.

Abstract

Orientador: Franco Giuseppe Dedini Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica Made available in DSpace on 2018-08-26T13:12:33Z (GMT). No. of bitstreams: 1 Costa_EduardodosSantos_M.pdf: 3795975 bytes, checksum: 57e8b74b69e23ca6a180dd32323f0a1e (MD5) Previous issue date: 2014 Resumo: Veículos Elétricos Híbridos representam, atualmente, uma alternativa para a redução do consumo de combustível fóssil utilizado pelos motores de combustão interna. Este trabalho analisa, em uma plataforma de simulação computacional e em condição experimental, o consumo de combustível de um veículo automotor, antes e após a hibridização. As simulações computacionais auxiliam, através de modelos matemáticos, um maior entendimento dos fenômenos físicos relacionados com os problemas de engenharia. Um modelo computacional bem elaborado possui um elevado grau de fidelidade em relação aos sistemas reais, tornando-se assim uma poderosa ferramenta de análise. A realização de experimentos, além de permitir uma comprovação de resultados, contribui para um refinamento dos modelos simulados. A tecnologia híbrida em estudo caracteriza-se pelo acoplamento de dois motores elétricos diretamente nas rodas traseiras do veículo. Por fim, busca-se a verificação da similaridade de comportamentos e/ou investigação de possíveis divergências entre o modelo matemático desenvolvido e os experimentos realizados. Um modelo de dinâmica veicular longitudinal descrito pela literatura é implementado no software Matlab/SimulinkTM e os resultados são comparados com os experimentos realizados em um dinamômetro de chassi Abstract: Hybrid Electric Vehicles currently represent an alternative to reducing fossil fuel consumption used by internal combustion engines. This paper analyses, in a platform of computational simulation and also in experimental condition, the vehicle fuel consumption, before and after hybridization. It checks the similarity of behaviors and/or the investigation of possible differences between the developed mathematical model and experiments performed. Computer simulations help, through mathematical models, a better understanding of physical phenomena related to engineering problems. A well elaborated computer model has a high fidelity degree with the real systems, becoming a powerful analysis tool. The experiments besides allowing a proof of results, they contribute to a refinement of the simulated models. The hybrid technology under study is characterized by the coupling of two electric motors directly to the rear vehicle wheels. A model for the vehicle longitudinal dynamics described in the literature is implemented in Matlab/SimulinkTM software and the results are compared with the experiments performed on a chassis dynamometer Mestrado Mecanica dos Sólidos e Projeto Mecanico Mestre em Engenharia Mecânic

Abstract

En aquest projecte s’analitza el comportament estàtic d’un sistema de tracció elèctrica complert per a un cotxe de Formula Student. Mitjançant la eina Simulink del programa Matlab, es realitzen una sèrie de simulacions en les quals s’analitza el comportament de dos motors síncrons d’imants permanents, els dos respectius inversors i la bateria que utilitzen com a alimentació. També s’estudia el sistema de control dels inversors, el Field-oriented Control, integrat en el propi inversor. Es farà una petita introducció al vehicle elèctric i a les seves principals caractrístiques, però posant molt ènfasis a l’explicació dels components que formen part del model estudiat en aquest treball.

Abstract

The study compares accidents at passive and active railway level crossings, and both immediate and background risk factors are considered. Passive railway level crossings have no warning devices, although there might be a static warning sign. Active level crossings are equipped with automatic devices warning road users of approaching trains. The data covers all fatal motor vehicle accidents at level crossings in Finland during the years 1991 to 2011 (n = 142). All these accidents have previously been investigated in detail by Road Accident Investigation Teams. Most of the accidents took place at passive level crossings. Compared to active level crossings, and related to the number of fatal accidents, passive level crossings have become proportionally more risky during the study period. Almost all the immediate risk factors in the accidents were of the human error type. Observation errors on the part of the road user were typical at passive level crossings, and risk taking at active level crossings. The environment did not support safe crossing in most of the accidents at passive level crossings. The speed limits of both the road and rail were high, visibility was insufficient, and the level crossing was often situated uphill. Active warning devices are effective in preventing accidents due to road user errors. Equipping the most dangerous passive level crossings with warning devices – low cost or conventional – would increase safety. Alternatively, some level crossings could be removed altogether. A minimum requirement is that the environmental factors at passive level crossings support safe crossing.

Abstract

Background Road transport workers (RTWs) are at high risk of exposure to several occupational carcinogens. However, there are gaps in knowledge regarding the extent and the circumstances of exposure. As a sub-study of the Australian Work Exposures Study, this study investigated the prevalence of occupational exposure in Australian RTWs. Methods A random sample of Australian working population was invited to a telephone interview regarding their current jobs. An automated expert-assessment procedure was applied to self-reported job-related tasks using a web-based application. 162 RTWs were included in this study. Results RTWs were exposed to diesel exhaust (97%), solar ultraviolet radiation (78%), environmental tobacco smoke (55%), benzene (29%), silica (15%), and asbestos (10%) at work. Besides driving on roads, vehicle maintenance-related tasks were the major source of carcinogen exposures among RTWs. Discussion Most RTWs are exposed to at least one carcinogen at work. We have identified tasks where the use of control measures could potentially reduce exposures. Am. J. Ind. Med. 59:31–41, 2016. © 2015 Wiley Periodicals, Inc.