Artigos de Revista

Tidal currents in an estuary carry all types of dissolved, suspended or floating material. Particle tracking models constitute powerful tools in assessing the transport of this material, through the study of the particles trajectoriesand settling positions. Thus, this work aims at using a Lagrangian particle tracking model driven by hydrodynamic fields to study the impact of morphologic anthropogenic and natural changes in sediments transport at Ria de Aveiro. In fact, as many coastal systems, Ria de Aveiro is in progressive degradation associated to the lack of maintenance and to the strong currents occurring in its channels, which erode theirprotective walls. Hence, the model VELApart, which is driven by the hydrodynamic model ELCIRC (previously calibrated for this lagoon), was applied for two configurations of the Ria de Aveiro: one representing the present situation of the lagoon and another representing a scenario with the enlargement of its flooded area. According tomodel results, morphologic changes influence the sediments pathways and final position, as well as the settling time. Generally for the flooded bathymetry the sediments travel a longer distance and the preferential zones of deposition are inside the flooded area, while for the present configuration sediments settle down in the mainadjacent channels. The settling times also increase with the enlargement of the flooded area.

A Iniciativa Nacional de Avaliação de Desempenho de ETA e ETAR urbanas «PASt21» (2009 2011) é um projecto de I&DT que teve como objectivos desenvolver e testar a segunda geração dos sistemas de avaliação de desempenho de ETA e ETAR urbanas. Quando aplicados na sua totalidade, estes sistemas envolvem o tratamento de um elevado volume de dados para o cálculo das variáveis e das medidas de avaliação de desempenho (indicadores e índices). A aplicação manual destes sistemas corresponderia portanto a uma tarefa morosa e complexa, propensa à geração de erros e com fraca reprodutibilidade.Assim, desenvolveu-se a ferramenta de cálculo PAStool®, apostando nas seguintes características: software de fácil utilização

This study discusses site-specific system optimizationefforts related to the capability of a coastal videostation to monitor intertidal topography. The systemconsists of two video cameras connected to a PC, and isoperating at the meso-tidal, reflective Faro Beach (Algarvecoast, S. Portugal). Measurements from the period February4, 2009 to May 30, 2010 are discussed in this study.Shoreline detection was based on the processing of varianceimages, considering pixel intensity thresholds for featureextraction, provided by a specially trained artificial neuralnetwork (ANN). The obtained shoreline data return ratewas 83%, with an average horizontal cross-shore root meansquare error (RMSE) of 1.06 m. Several empiricalparameterizations and ANN models were tested to estimatethe elevations of shoreline contours, using wave and tidaldata. Using a manually validated shoreline set, the lowestRMSE (0.18 m) for the vertical elevation was obtainedusing an ANN while empirical parameterizations based onthe tidal elevation and wave run-up height resulted in anRMSE of 0.26 m. These errors were reduced to 0.22 m afterapplying 3-D data filtering and interpolation of thetopographic information generated for each tidal cycle.Average beach-face slope tan(

Results from the application of Persistent Scatterers Interferometry in Lisbon Metropolitan Area revealed two previously unknown subsiding urban areas: one (Laranjeiras) is located in the center of Lisbon; another (Vialonga) is to be found toward the North, in an industrial region crossed by Lisbon's main highway and railway lines. The two subsiding sectors are bordered by sharp velocity gradients, and the subsidence pattern appears partially delimited by mapped geologic faults. Surface geology and urbanization alone are unable to explain the phenomena. In the Vialonga area, the historical record of water pore pressure shows a clear decline of the levels (up to 65 m in 27 years), providing evidence of over-exploitation of groundwater resources. Limited information from wells drilled inside and outside the subsidence area points to a spatial correlation between the subsidence and the water pressure levels, and suggests that faults could be acting as hydraulic barriers in the aquifer system. The surface subsidence detected is probably caused by compaction of a clay-rich Oligocene-aged aquitard, led by over-exploitation of adjacent aquifers. The same Oligocene aquitard layer is present in the Laranjeiras area, immediately bellow a multi-layered sand–clay–limestone Miocene aquifer, but further work is needed to diagnose the possibility of over-exploitation of groundwater here. In this work we were able to independently confirm the PSI results, by comparing autonomous PSI results processed for the same geographical areas, and by comparing PSI with leveling and continuous GPS derived subsidence velocities, whose close match provided further ground validation of the space-borne PSI technique.

Results from the application of Persistent Scatterers Interferometry in Lisbon Metropolitan Area revealed twopreviously unknown subsiding urban areas: one (Laranjeiras) is located in the center of Lisbon; another(Vialonga) is to be found toward the North, in an industrial region crossed by Lisbon's main highway andrailway lines. The two subsiding sectors are bordered by sharp velocity gradients, and the subsidence patternappears partially delimited by mapped geologic faults. Surface geology and urbanization alone are unable toexplain the phenomena. In the Vialonga area, the historical record of water pore pressure shows a cleardecline of the levels (up to 65 m in 27 years), providing evidence of over-exploitation of groundwaterresources. Limited information from wells drilled inside and outside the subsidence area points to a spatialcorrelation between the subsidence and the water pressure levels, and suggests that faults could be acting ashydraulic barriers in the aquifer system. The surface subsidence detected is probably caused by compaction ofa clay-rich Oligocene-aged aquitard, led by over-exploitation of adjacent aquifers. The same Oligoceneaquitard layer is present in the Laranjeiras area, immediately bellow a multi-layered sand

Notre propos est une invitation à réfléchir aux activités formelles/informelles dans les espaces urbains. A Lisbonne, la Place Martim Moniz - et à Rio de Janeiro, la plage de Copacabana - seront explorées, à partir de nos travaux de recherches empiriques. Nous avons revisité nos terrains pour montrer que la vie quotidienne dans ces deux villes mêlent étroitement l'informel et le formel et cela dans des proportions parfois, difficiles à évaluer mais en tous les cas, significatives selon le moment, le lieu et le type d'activités que de nombreux citadins pratiquent. Nous souhaitons commencer à construire une démarche comparative pour analyser le processus d'informalité dans deux contextes différents. Mots-clés: espace public, formalité, informalité, micro géographies quotidiennes.

Application of cork oak wood as solid wood elements for flooring was experimentally assessed by measuring dimensional stability to air humidity and liquid water, response to loads applied while in serviceand abrasion due to people traffic using boards cut from the stem of five mature cork oak trees (Quercus suber L.). The results obtained from dimensional stability tests showed a performance of a medium movementin-service and small swelling in liquid water (2

Sapwood samples of Pinus pinaster wood weretreated with a 70% furfuryl alcohol mixture.Weight percent gain (WPG), equilibrium moisture content, dimensional stability, MOE, bending strength, hardness, density and durability were determined.WPG was on average 38%. Equilibrium moisture content decreased more than 40%. Dimensional stability increased reaching an ASE of 45%.MOE was little affected by the treatment but bending strength increased by about 6%.Hardness increased by about 50%, and density by 37%.Mass loss due to Postia placenta and Coniophora puteana decreased by 96% and 86%, respectively. Furfurylation of Pinus pinaster wood shows an interesting potential to improve the wood quality for solid timber products.

In designing tunnels for fires, the design fire needs to be quantified. Design fires form the base input for emergency ventilation, evacuation, and structural design analyses. A design fire is the idealization of a real fire that may occur in a tunnel. It describes, quantitatively, the characteristics of a particular fire with respect to time and space, e.g. fuel state (solid, liquid, or gas), fuel type and quantity, fuel configuration and location, heat release rate, rate of growth, production rate of combustion products (smoke, CO, CO2, etc.). A design fire is in general defined in terms of heat release rate, and species output as functions of time. This paper summarizes the efforts to develop a set of idealized design fire curves as a useful tool for road tunnel fire risk assessment. The developed idealized design fire curves include the following phases: (1) incubation phase, (2) growth phase, (3) fully-developed phase, and (4) decay phase.

N/A