Melhoria da qualidade na indústria de recauchutagem de pneus

Mestrado em Engenharia e Gestão IndustrialThe general objective of this project is to describe the application of quality tools in an uncommon industrial environment - tire retreading. The specific goals are to better understand the root causes of the main quality problems that result from the production process, to rank those causes taking into account the importance of thei r occurrence, to ident ify the critical step of the production process in view of the main problem identi fied, and to explore the potential causes of problems in that step. The methodology used combined basic and new quality tools in order to identi fy, classify and analyse the main problems according to their priority (weight of importance). The tools used were Pareto Chart, Brainstorming, Fishbone Diagram and Matrix diagram. The company where the study was carried out was the Ken Ti re Industrial Complex, which is one of the biggest Ti re Retreading Companies in Middle East. The data was collected during all the year of 2009 from quality and production records. The main problems were classified according the cost of defects that happen during the production process and the use of appropriate improvement quality tools is proposed in order to minimize the impact of defect causes in final products and semi -products.O objectivo geral deste projecto é de descrever a aplicação de ferramentas da qualidade num ambiente industrial pouco comum – a recauchutagem de pneus. Os objectivos específicos são: (i) compreender melhor as causas dos principais problemas que resultam do processo de produção; (ii ) classificar essas causas levando em consideração a importância da sua ocorrência; (iii) identi ficar as etapas críticas do processo de produção na perspectiva do principal problema identi ficado (iv) e explorar as potenciais causas dos problemas que ocorrem nessas etapas. A metodologia usada combinou novas ferramentas da qualidade com ferramentas básicas de forma a identificar, classificar e analisar os principais problemas de acordo com as suas prioridades. As ferramentas usadas foram o diagrama de Pareto, Brainstorming, Diagrama de espinha de peixe e o diagrama de mat riz. A empresa onde o estudo foi realizado foi a Ken Ti re Industrial Complex, que é uma das maiores empresas de Recauchutagem de pneus do Médio Oriente. A informação foi recolhida durante o ano 2009 com base em registos da área da qualidade e da produção. Os principais problemas foram classificados de acordo com o custo dos defeitos que aconteceram durante o processo de produção. Foi proposta a utilização de ferramentas de melhoria da qualidade apropriadas para minimizar o impacto das causas dos defeitos nos produtos finais e nos semi-produtos

Impacte da interação entre veículos motorizados e bicicletas na escolha de rota, desempenho de tráfego, emissões e segurança

Mobility in urban areas is highly complex because of the variety of possible facilities and routes, the multitude of origins and destinations, the increase of population and traffic. Increased use of active modes, such as cycling, presents economic and environmental benefits, and contributes to health improvement. However, it can lead to safety concerns such as bicycles sudden or unexpected movements mainly when circulating together with motor vehicles (MVs) or when there is an overtaking situation between MVs and bicycles. The main goal of this doctoral thesis is to quantify and assess the impact of the interaction motor vehicle-bicycle on traffic performance, road safety and emissions to define a multi-objective analysis model of the impacts regarding the use of motor vehicle and/or bicycle. The thesis was focused on three main topics developed based on the evaluation of traffic performance, safety and emissions at urban areas : (i) to perform a multi-objective analysis in an integrated manner of the traffic performance, pollutant emissions and road conflicts between bicycles and MVs at a signalized intersection; (ii) to assess the driving volatility in MV-bicycle interactions at two-lane roundabouts and its impacts on safety, pollutant emissions and traffic performance; and (iii) to analyze the impacts of the overtaking lateral distance between a bicycle and a MV on road safety and energy consumption at two-lane urban roads. Second-by-second bicycle and vehicle dynamic data were collected using GPS travel recorders. The methodology developed in this thesis was applied based on real world case studies at different urban road types in the city of Aveiro, Portugal. The present work uses a microscopic simulation platform of traffic (VISSIM), road safety (Surrogate Safety Assessment Methodology – SSAM) and emissions (Vehicle Specific Power – VSP) to analyze traffic operations, road safety concerns and to estimate carbon dioxide (CO2), nitrogen oxide (NOX), carbon monoxide (CO), and hydrocarbons (HC) pollutant emissions. Furthermore, the Fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was used in order to address the multi-objective analysis of traffic performance, road conflicts between MVs and bicycles, and emissions. Bicycle Specific Power (BSP) and VSP concepts were used in order to analyze the impacts on cyclist and vehicle energy consumption as well. The findings showed that roundabouts present, in general, better traffic performance (number of stops and travel time reduced in 78% and 14%, respectively) and less emissions (CO2, NOX, and HC decreased 9%, 7%, and 12%, respectively) than other intersections, even with high demand of cyclists (270 bicycles per hour). Regarding safety, roundabout layout lead to more severe conflicts and potential crashes while the number of total conflicts can be reduced significantly (-49%). It was also found that the impact of MVs and bicycles speeds, as well as roundabout design, were more important factors than bicycle volumes at roundabouts. Considering the MV-bicycle interaction at two-lane roundabout, the results of emissions dictated good relationships (R2 > 70%) between acceleration and VSP modes distributions. Finally, the findings showed 50% of overtaking lateral distance (between bicycle and MV) lower than 0.5m in both morning and afternoon peak hours. Moreover, it was found that there was a good fit between overtaking lateral distance and traffic volumes in morning (R2 = 72%) and afternoon (R2 = 67%) peak hours. The findings of this research can be useful for policy makers of the mobility and road safety fields, municipalities, road designers, and traffic engineers.A complexidade inerente à mobilidade em áreas urbanas está associada ao excesso de tráfego e à multiplicidade de origem-destinos, rotas e motivos de viagem. O incremento do uso dos modos suaves, nomeadamente da bicicleta, apresenta benefícios económicos e ambientais, contribuindo para a melhoria da saúde. No entanto, a presença de bicicletas acarreta preocupações ao nível da segurança dos ciclistas. As questões de segurança podem estar relacionadas com movimentos súbitos ou inesperados dos ciclistas, principalmente quando circulam em conjunto com veículos motorizados (VMs), ou quando há uma situação de ultrapassagem entre VMs e bicicletas. O principal objetivo da Tese de Doutoramento consistiu em quantificar e avaliar o impacto da interação entre veículos motorizados e bicicletas ao nível do desempenho de tráfego, segurança rodoviária e emissões para definir um modelo de análise multiobjetivo. A tese foi focada em três tópicos principais, desenvolvidos com base na avaliação do desempenho do tráfego, segurança e emissões em áreas urbanas: (i) análise multiobjetivo de forma integrada do desempenho do tráfego, emissões poluentes e conflitos rodoviários entre bicicletas e VMs em intersecções sinalizadas; (ii) avaliação da volatilidade de condução em interações VM-bicicleta em rotundas de duas vias e seus impactos na segurança, emissões de poluentes e desempenho de tráfego; e (iii) análise dos impactos ao nível de segurança rodoviária e consumo de energia em vias urbanas, com a avaliaçao da distância lateral de ultrapassagem entre uma bicicleta e um VM. Os dados da dinâmica do velocípede e do VM foram recolhidos e gravados segundo a segundo com um GPS. A metodologia desenvolvida nesta tese foi aplicada tendo por base os estudos de caso associados a diferentes tipos de vias urbanas na cidade de Aveiro, Portugal. O presente trabalho utiliza uma plataforma de simulação microscópica de tráfego (VISSIM), segurança rodoviária (SSAM) e emissões (Potência Específica do Veículo - VSP) para analisar as operações relacionadas com tráfego, questões com segurança rodoviária e estimar o dióxido de carbono (CO2), emissões de poluentes como o óxido de azoto (NOX), monóxido de carbono (CO) e hidrocarbonetos (HC). Além disso, para a análise multiobjetivo do desempenho do tráfego, conflitos rodoviários entre VMs e bicicletas, e emissões, o algoritmo genético NSGA-II (Nondominated sorted genetic algorithm II) foi utilizado. As metodologias de Potência Específica de Bicicleta (BSP) e VSP foram usados para analisar os impactos no consumo de energia do ciclista e do veículo, respetivamente. Os resultados mostraram que, em geral, as rotundas apresentam melhor desempenho de tráfego (número de paragens e tempo de viagem reduzidos em 78% e 14%, respetivamente) e menores emissões (CO2, NOX e HC diminuíram 9%, 7% e 12%, respetivamente) quando comparadas a outras interseções, mesmo com elevados níveis de ciclistas (270 bicicletas por hora). Em relação à segurança, o design da rotunda tende a favorecer a ocorrência de conflitos mais graves e potenciais acidentes, apesar do número total de conflitos poder diminuir significativamente (menos 49%). Descobriu-se também que o impacto das velocidades de circulação dos VMs e das bicicletas, bem como o design da rotunda constituem fatores mais importantes do que o volume de ciclistas nas rotundas. Considerando a interação VM-bicicleta numa rotunda de duas vias, os resultados das emissões sugerem boas relações (R2> 70%) entre as distribuições dos modos de aceleração e VSP. Por fim, os resultados mostraram que em 50% das ultrapassagens a distância lateral entre o velocípede e o VM foi menor que 0,5m, tanto na hora de ponta da manhã como da tarde. Além disso, verificou-se um bom ajuste entre a distância lateral de ultrapassagem e os volumes de tráfego nas horas de ponta da manhã (R2 = 72%) e da tarde (R2 = 67%). A metodologia e resultados desta investigação poderão ser utilizados por decisores políticos na área da mobilidade e da segurança rodoviária, câmaras, gestores e engenheiros de tráfego.Programa Doutoral em Engenharia Mecânic

Micro driving behaviour in different roundabout layouts: pollutant emissions, vehicular jerk, and traffic conflicts analysis

Driving behaviour affects both road safety and the environment, either positively or negatively. An unsafe driving behaviour characterized by hard acceleration/braking (also called driving volatility) can lead to an increase in emissions. Driving volatility can occur due to driving style, traffic, or road conditions. Although roundabouts present better safety performance than other traffic-control treatments, different layouts may lead to different levels of traffic-related impacts. This paper aims to evaluate vehicle movements through three types of roundabouts (Single-lane (SL), Compact two-lane (CTL), and Multi-lane (ML)) focusing on assessing the impact of driving volatility on traffic conflicts and pollutant emissions. A micro driving behaviour analysis of emissions, driving volatility, and conflicts were conducted for the links of the entry, circulating, and exit areas of the studied roundabouts. Speed was used as a variable parameter directly related to the driver while vehicular jerk and traffic conflicts, as well as global (carbon dioxide – CO2) and local (nitrogen oxides – NOx) pollutants were used to evaluate the traffic safety and emissions performance, respectively. Field measurements obtained from a light-duty probe vehicle equipped with an on-board diagnostic reader on three different layout roundabouts located in suburban environments were used to develop a microscopic traffic simulation for the baseline. Simulations were conducted using VISSIM, emissions were estimated using the Vehicle Specific Power (VSP) methodology, and the Surrogate Safety Assessment Model (SSAM) was applied for estimating the traffic conflicts between motor vehicles. Four speed-distribution scenarios were considered, and associated impacts were evaluated for each roundabout. In general, speed variation and subsequently vehicular jerk had more impact on traffic conflicts than pollutant emissions. The number of conflicts in the exit area was less than entry and circulating in all roundabout designs but ML presented more traffic conflicts.publishe

Impacte da presença de ciclovias no desempenho do tráfego rodoviário, segurança rodoviária e emissões de poluentes em áreas urbanas

A segurança é apontada como o principal fator para a falta de adesão à bicicleta enquanto meio de transporte. O principal objetivo deste trabalho é analisar as diferenças relativamente ao desempenho do tráfego, emissões e segurança do ciclista a circular em faixas de rodagem com e sem vias dedicadas para a prática do ciclismo. A metodologia deste trabalho tem como base um caso de estudo real que utiliza uma plataforma de simulação microscópica de tráfego (VISSIM), segurança rodoviária (SSAM) e emissões (Vehicle Specific Power – VSP) para analisar tempo de viagem, conflitos e estimar emissões de dióxido de carbono (CO2) e de óxidos de azoto (NOx). O software PC-CRASH foi usado para analisar efeito de velocidade de circulação de veículos motorizados em acidentes envolvendo ciclistas

Impact of motor vehicle-bicycles interaction on route selection, traffic performance, emissions and safety: a look to driving volatility

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Driving Information in a Transition to a Connected and Autonomous Vehicle Environment: Impacts on Pollutants, Noise and Safety

The main objective of this vision paper is to present the project “DICA-VE: Driving Information in a Connected and Autonomous Vehicle Environment: Impacts on Safety and Emissions”, which aims to develop an integrated methodology to assess driving behavior volatility and develop warnings to reduce road conflicts and pollutants/noise emissions in a vehicle environment. A particular attention will be given to the interaction of motor vehicles with vulnerable road users (pedestrians and cyclists). The essence of assessing driving volatility aims the capture of the existence of strong accelerations and aggressive maneuvers. A fundamental understanding of instantaneous driving decisions (through a deep characterization of individual driver decision mechanisms, distinguishing normal from anomalous) is needed to develop a framework for optimizing these impacts. Thus, the research questions are: 1) Which strategies are adopted by each driver when he/she performs short-term driving decisions and how can these intentions be mapped, in a certain road network?; 2) How is driver’s volatility affected by the proximity of other road users, namely pedestrians or cyclists?; 3) How can driving volatility information be integrated into a platform to alert road users about potential dangers in the road infrastructure and prevent the occurrence of crash situations?; 4) How can anomalous driving variability be reduced in autonomous cars, in order to prevent road crashes and have a performance with a minimum degree of emissions? This paper brings a literature review on this topic and an evaluation of methods that can be used to assess driving behavior patterns and their influence on road safety, pollutant and noise emissions.publishe

Cycling at Intersections: a multi-objective assessement for traffic, emissions and safety

This paper evaluated in an integrated manner the traffic performance, pollutant emissions and road conflicts between bicycles and motor vehicles at a signalized intersection. Two alternative scenarios were examined: (i) Bicycles increment and motor vehicles replacement within the cycle-fixed traffic signal; (ii) Replacing the existing traffic control by a conventional two-lane roundabout and evaluating the impacts of bicycles increment. For each scenario, bicycle demand was varied from 9 to 270 bicycles per hour. Traffic flow and vehicle dynamic data were collected from a three-leg signalized intersection in Aveiro, Portugal. The microscopic traffic model (VISSIM) paired with an emission (Vehicle Specific Power – VSP) methodology and safety (Surrogate Safety Assessment Methodology – SSAM) model were used to assess intersection-specific operations. The Fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was used to find the optimal bicycle demands. The results showed that two-lane roundabout outperformed the existing traffic control, namely in highest bicycle demand scenario (number of stops and travel time reduced in 78% and 14%, respectively; CO2, NOX, and HC decreased 9%, 7%, and 12%, respectively). It was also found that the number of conflicts was significantly reduced (-49%) with this latter layout even in maximum bicycle demand scenario (270 bicycles per hour). However, roundabout layout lead to more severe conflicts and potential crashes. The analysis showed that bicycle demands of 75, 95 and 110 bicycles per hour delivered good environmental and safety outcomes for the intersection. published Document type: Articl

Impact of the interaction between motor vehicles and bicycles on route selection, traffic performance, emissions and safety

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Impact of motor vehicles-bicycles interaction on route selection, traffic performance, emissions and safety

Motor vehicles routing problems (VRP) and drivers’ behavior studies already have been conducted widely in transportation engineering studies. Considering cyclist safety, multi-objective optimal routing strategy for motor vehicle (MV)-bicycle need to more research. Urban areas are complex because of variety of possible routes between origin and destination and different design of roundabouts, intersections and lanes for road users. MV-bicycle interaction can be one of the key challenges regarding the safety concerns besides emissions and traffic performance as well. Drivers’ instantaneous decisions regarding speed and acceleration represent the driving behavior. MVs acceleration/deceleration and the time rate of change of acceleration (jerk) can result in the volatility driving behavior with significant impact on cyclist safety. This PhD thesis is focused on two main sections which is developed based on the previous presented work at GET2017; (i) the main characteristics/impacts of MV-bicycle interaction for a proper route selection (ii) the main characteristics/impacts of MV-bicycle volatility on safety, emissions and traffic performance at two different two-lane roundabouts. Traffic flow, and bicycle GPS and flow data were collected from urban area in the city of Aveiro, Portugal. The present work uses a microscopic simulation platform of traffic (VISSIM). Vehicle Specific Power (VSP) methodology was used to estimate pollutant emissions produced by vehicles and Surrogate Safety Assessment Methodology (SSAM) was used to assess the safety concerns. Three dimensional Pareto Fronts of signal operation, which were expressed through traffic performance, emissions and safety, were analyzed using the fast Non-Dominated Genetic Algorithm (NSGA-II) for optimum route selection. Moreover, each point of optimum solutions from Pareto front based on its travel time, safety and emissions value can be defined in one or more selected routes. Regarding the impact of MV-bicycle at roundabouts, the findings showed that the trend of jerk variation was identical for both bicycles and MVs regardless of roundabout design with a higher severity for MVs. It was also found that the impact of speed and roundabout design was more important than bicycle volume at roundabouts. Finally, the results of emissions dictated good relationships (R2 > 0.70) between acceleration and VSP modes distributions in both case studies