4 resultados para indice
Resumo:
Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Ciência e Sistemas de Informação Geográfica
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Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente
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Estuaries and other transitional waters are complex ecosystems critically important as nursery and shelter areas for organisms. Also, humans depend on estuaries for multiple socio-economical activities such as urbanism, tourism, heavy industry, (taking advantage of shipping), fisheries and aquaculture, the development of which led to strong historical pressures, with emphasis on pollution. The degradation of estuarine environmental quality implies ecologic, economic and social prejudice, hence the importance of evaluating environmental quality through the identification of stressors and impacts. The Sado Estuary (SW Portugal) holds the characteristics of industrialized estuaries, which results in multiple adverse impacts. Still, it has recently been considered moderately contaminated. In fact, many studies were conducted in the past few years, albeit scattered due to the absence of true biomonitoring programmes. As such, there is a need to integrate the information, in order to obtain a holistic perspective of the area able to assist management and decision-making. As such, a geographical information system (GIS) was created based on sediment contamination and biomarker data collected from a decade-long time-series of publications. Four impacted and a reference areas were identified, characterized by distinct sediment contamination patterns related to different hot spots and diffuse sources of toxicants. The potential risk of sediment-bound toxicants was determined by contrasting the levels of pollutants with available sediment quality guidelines, followed by their integration through the Sediment Quality guideline Quotient (SQG-Q). The SQG-Q estimates per toxicant or class was then subjected to georreferencing and statistical analyses between the five distinct areas and seasons. Biomarker responses were integrated through the Biomarkers Consistency Indice and georreferenced as well through GIS. Overall, in spite of the multiple biological traits surveyed, the biomarker data (from several organisms) are accordant with sediment contamination. The most impacted areas were the shipyard area and adjacent industrial belt, followed by urban and agricultural grounds. It is evident that the estuary, although globally moderately impacted, is very heterogeneous and affected by a cocktail of contaminants, especially metals and polycyclic aromatic hydrocarbon. Although elements (like copper, zinc and even arsenic) may originate from the geology of the hydrographic basin of the Sado River, the majority of the remaining contaminants results from human activities. The present work revealed that the estuary should be divided into distinct biogeographic units, in order to implement effective measures to safeguard environmental quality.
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Os modelos de previsão da degradação dos pavimentos são um elemento-chave para os sistemas de gestão dos pavimentos sendo utilizados para prever a evolução das suas condições de circulação. O presente trabalho tem como objetivo estabelecer um modelo de previsão da evolução do indice de irregularidade longitudinal (IRI), principal indicador da qualidade funcional de um pavimento. Para tal, foram utilizados dados da base de dados da empresa Infraestrutruras de Portugal (IP). Esta mantém um programa de monitorização da rede com o objetivo de controlar a qualidade de serviço e gerir de forma consciente os recursos disponÃveis. O modelo HDM-4 foi implementado em código do programa Matlab com o objetivo de apoiar este estudo. Primeiro, procedeu-se à avaliação da forma com que os parâmetros do modelo HDM-4 atuam sobre o valor do IRI no modelo HDM-4. Posteriormente, procurou-se ajustar os resultados obtidos efetuando calibrações, com o intuito de minimizar o erro entre os valores calculados e os valores medidos pela IP. Concluiu-se que é possÃvel estabelecer modelos com base no modelo HDM-4, em pavimentos flexÃveis, ajustados à rede rodoviária nacional. No entanto, para serem incluidos fatores que deveriam ser contabilizados no modelo, deverão ser realizadas algumas alterações na base de dados a utilizar.