Artigos de Revista

Neste artigo é analisado o risco de incêndio numa instalação de tratamento de resíduos sólidos urbanos, nomeadamente ao nível da sua fossa de deposição desses resíduos. Foram realizadas simulações do desenvolvimento do incêndio usando um modelo de duas zonas, o Consolidated Model of Fire and Smoke Transport (CFAST) e um modelo de campo,o Fire Dynamics Simulator and Smokeview (FDS-SMV), ambos do National Institute of Standards and Technology (NIST), sendo os resultados analisados e discutidos.

New experiments under sheet flow conditions were conducted in an oscillating water tunnel to study the effects of flow acceleration on sand transport.The simulated hydrodynamic conditions considered flow patterns that drive cross-shore sediment transport in the nearshore zone: the wave nonlinearitiesassociated with velocity and acceleration skewness and a negative mean current, the undertow. Net transport rates were evaluated from the sedimentbalance equation and show that (1) the acceleration skewness in an oscillatory flow produces a net sediment transport in the direction of the highestacceleration; (2) the net transport in the presence of an opposing current is negative, against the direction of the highest acceleration, and reduces with anincrease in flow acceleration; and (3) velocity skewness increases the values of the net onshore transport rates.

This article defines short-term (tidal cycle) sediment-transport patterns at a backbarrier beach based on detailed fieldstudies. Fieldwork was planned to record nonstorm, spring tide conditions that enable the definition of backgroundsediment dynamics at the study area. The experiment was set at two beach morphologies: beach face and sandbank.Current meters were deployed at both sites. Fluorescent tracer techniques were applied to determine rates and directionof transport. Topographic surveys and sediment sampling were undertaken. During the experiment, limited tracerdisplacement and small morphological changes occurred. The low magnitude changes are representative of predominant,low-energy hydrodynamic conditions. Sediment transport was primarily longshore orientated and dependent on thevelocity of tidal currents. Tidal currents had the potential for sediment transport only during a short period of the tidalcycle and had higher velocities during ebb, which results in a net sediment transport orientated towards the nearby inlet.It is suggested that there is dependence on sediment transport rate at the study site and on the variability of tidalcurrents, which are greatly influenced by the distance to, and conditions of, the nearby Anca

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SOPRO1.0, constituiu a primeira versão do pacote de informática desenvolvido no Laboratório Nacional de Engenharia Civil, para a caracterização da agitação marítima em zonas costeiras e de simulação da navegação no acesso ou no interior de zonas portuárias. É composto por um conjunto de bases de dados, uma interface com o utilizador e um conjunto de módulos de cálculo. A interface com o utilizador permite o armazenamento e manipulação de dados, a execução dos modelos de propagação da agitação marítima e de simulação da trajectória de navios, assim como a obtenção dos resultados e a criação das correspondentes visualizações gráficas. O pacote foi criado no sistema gestor de base de dados Microsoft Access

In this work, we present the results of an analytical method developed for detailed pigment identification, stratigraphy, and degradation of the paint layers of mural paintings applied in the study of the 17th century frescoes from the Misericordia Church of Odemira (Southwest Portugal). In situ X-ray fluorescence spectrometry analyses were performed on three panels of the mural paintings and complemented by colorimetric measurements. The different color areas were also sampled as microfragments (approx. 1 mm2)that were studied as taken or mounted in epoxy resin to expose the different paint layers. The microfragments of paint layers and their cross sections were characterized by optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray spectrometry. Furthermore, elemental analysis was obtained with spatially resolved confocal synchrotron radiation micro-X-ray fluorescence spectrometry performed at ANKA synchrotron FLUO beamline. Occasionally, phase analysis by micro-X-ray diffraction was also performed. Results from the different techniques allowed pigment identification and, in some cases, the evaluation of color changes due to degradation processes and, considering the Southern Portugal geology, the identification of their possible provenance. The pigments used were essentially yellow, brown and red ochres, smalt blue, copper green, and black earths, probably from local sources.

The hydrodynamics of the surf zone in front of collapsing coastal dunes are examined. The data was gatheredduring the HYDRALAB-III funded Transnational Access experiment performed at the CIEM large-scale waveflume. Here, it is presented results of the cross-shore evolution of several flow parameters at four positions. Despikedand band-pass filtered ADV velocity data were used to enable a focus on only the short-wave component.As the waves approach the shore they reduce their (velocity) skewness, but increase their vertical asymmetry.Despite the non-negligible wave reflection, the theoretical wave model of Abreu et al. (2010) was applied tosuccessfully reproduce the measured velocities. Lastly, an estimate of the bed shear stress exerted by the shortwavecomponents is presented.