4 resultados para Planets and satellites: gaseous planets

em Instituto Politécnico do Porto, Portugal


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No mundo contemporâneo globalizado, definido pela sua qualidade essencialmente fluida e instável, o carácter distintivo da viagem parece dissolver-se face à contracção do planeta, à economia das ―trocas simbólicas‖ e a um alegado processo de diluição das diferenças e de homogeneização cultural. Com efeito, a mediatização da sociedade e a proliferação icónica contemporâneas produzem um aparente estado de saturação da geografia real e de multiplicação de lugares enquanto representações e imagens, permitindo pôr em causa a própria necessidade e urgência de deslocação, bem como admitir a abolição do ―estatuto de privilégio‖ de certos lugares e a derradeira quebra no conceito aurático das férias e das viagens, tradicionalmente assente em antinomias cruciais entre o quotidiano/familiar e o diferente/extraordinário. O presente artigo propõe-se abordar o paradigma da mobilidade contemporânea, nomeadamente no que diz respeito à traumática aniquilação do espaço e do tempo e ao seu impacto fortemente disruptivo sobre a dimensão ontológica de uma prática cultural cujo poder aurático se encontra tradicionalmente relacionado com a conquista de distâncias, a percepção de diferenças e a experiência de alteridade. O artigo pretende, por outro lado, refutar a declaração pós-moderna de que a familiarização com o outro conduz a uma diminuição do potencial de choque cultural no turismo contemporâneo, discutindo a relevância e a prevalência da busca de contraste e formas de vivência de alteridade no complexo novelo de motivações da viagem turística contemporânea.

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Over the past few decades there has been some discussion concerning the increase of the natural background radiation originated by coal-fired power plants, due to the uranium and thorium content present in combustion ashes. The radioactive decay products of uranium and thorium, such as radium, radon, polonium, bismuth and lead, are also released in addition to a significant amount of 40K. Since the measurement of radioactive elements released by the gaseous emissions of coal power plants is not compulsory, there is a gap of information concerning this situation. Consequently, the prediction of dispersion and mobility of these elements in the environment, after their release, is based on limited data and the radiological impact from the exposure to these radioactive elements is unknown. This paper describes the methodology that is being developed to assess the radiological impact due to the raise in the natural background radiation level originated by the release and dispersion of the emitted radionuclides. The current investigation is part of a research project that is undergoing in the vicinity of Sines coal-fired power plant (south of Portugal) until 2013. Data from preliminary stages are already available and possible of interpretation.

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STRIPPING is a software application developed for the automatic design of a randomly packing column where the transfer of volatile organic compounds (VOCs) from water to air can be performed and to simulate it’s behaviour in a steady-state. This software completely purges any need of experimental work for the selection of diameter of the column, and allows a choice, a priori, of the most convenient hydraulic regime for this type of operation. It also allows the operator to choose the model used for the calculation of some parameters, namely between the Eckert/Robbins model and the Billet model for estimating the pressure drop of the gaseous phase, and between the Billet and Onda/Djebbar’s models for the mass transfer. Illustrations of the graphical interface offered are presented.

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This work aims to characterize levels and phase distribution of polycyclic aromatic hydrocarbons (PAHs) in indoor air of preschool environment and to assess the impact of outdoor PAH emissions to indoor environment. Gaseous and particulate (PM1 and PM2.5) PAHs (16 USEPA priority pollutants, plus dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were concurrently sampled indoors and outdoors in one urban preschool located in north of Portugal for 35 days. The total concentration of 18 PAHs (ΣPAHs) in indoor air ranged from 19.5 to 82.0 ng/m3; gaseous compounds (range of 14.1–66.1 ng/m3) accounted for 85% ΣPAHs. Particulate PAHs (range 0.7–15.9 ng/m3) were predominantly associated with PM1 (76% particulate ΣPAHs) with 5-ring PAHs being the most abundant. Mean indoor/outdoor ratios (I/O) of individual PAHs indicated that outdoor emissions significantly contributed to PAH indoors; emissions from motor vehicles and fuel burning were the major sources.