Interpretation of Pliocene littoral blocks in eastern Leiria area (central Portugal)

Comunicação apresentada ao VIII Congresso Nacional de Geologia, em Braga (9-16 de Julho 2010)Foram estudados blocos que atingem 2 metros de diâmetro, constituídos por arenito silicioso ou doleritos, que se encontram na área do sinclinal de Pousos (a leste de Leiria), estratigraficamente atribuíveis à transição Zancliano-Placenciano. Interpretamos a génese dos blocos siliciosos a partir da erosão litoral de arenitos siliciosos da Formação de Bom Sucesso e os de rocha básica a partir de doleritos, durante o máximo transgressivo pliocénico.This paper analyses the large blocks, consisting of siliceous sandstone and basic rock that are in the eastern area of Leiria (Pousos sinclyne), with Zanclean to Placenzian age. We assumed the origin of the siliceous sandstone from the destruction by marine erosion of siliceous materials from the Senhora do Bom Sucesso formation and the basic blocks from the dolerites during the Pliocene maximum transgressive

Propriedades hidráulicas dos solos e modelação para a optimização da rega considerando a dinâmica do azoto e dos sais

Doutoramento em Engenharia dos Biossistemas - Instituto Superior de AgronomiaModeling has become an essential tool for implementing better irrigation and fertilization practices. The HYDRUS software package is currently one of the few models capable of considering multicomponent geochemistry and evaluating multiple environmental problems in an integrated way. The model was used to simulate water movement and solute transport in two complex experiments carried out under field conditions, between 2004 and 2010. The field experiments were helpful to identify the main physical and chemical processes influencing soil water flow and multicomponent solute transport in soils irrigated with saline waters. They were further useful for evaluating different irrigation water quality and fertilization scenarios while considering soil salinization/sodification risks, root nutrient uptake, nutrient leaching, and crop yield. HYDRUS proved to be a powerful tool for establishing sound irrigation policies. However, the considerable demand on input data, namely, soil hydraulic properties, has been limiting its use (and other reactive transport models). Different pedotransfer functions (PTFs) were thus established to indirectly estimate soil hydraulic properties from the soil information available in the PROPSOLO database. A set of class-PTFs were developed to estimate water retention properties after grouping data by soil texture, soil horizon, and bulk density. A different procedure was also presented to estimate water retention properties from particle size distribution using the soil texture triangle and ordinary kriging. Finally, a set of PTFs were established for Cape Verde soils. All these PTFs may have multiple applications in irrigation management and watershed modelling. However, it is still necessary to further extend those PTFs to other regions of Portugal and Cape Verde, and to gain more knowledge on the hydraulic conductivity functions of those soils so that they can be used in reactive transport modelin

Influence of bed elevation discordance on flow patterns and head losses in an open-channel confluence

Confluences play a major role in the dynamics of networks of natural and man-made open channels, and field measurements on river confluences reveal that discordance in bed elevation is common. Studies of schematized confluences with a step at the interface between the tributary and the main channel bed reveal that bed elevation discordance is an important additional control for the confluence hydrodynamics. This study aimed to improve understanding of the influence of bed elevation discordance on the flow patterns and head losses in a right-angled confluence of an open channel with rectangular cross-sections. A large eddy simulation (LES)-based numerical model was set up and validated with experiments by others. Four configurations with different bed discordance ratios were investigated. The results confirm that, with increasing bed elevation discordance, the tributary streamlines at the confluence interface deviate less from the geometrical confluence angle, the extent of the recirculation zone (RZ) gets smaller, the ratio of the water depth upstream to that downstream of the confluence decreases, and the water level depression reduces. The bed elevation discordance also leads to the development of a large-scale structure in the lee of the step. Despite the appearance of the large-scale structure, the reduced extent of the RZ and associated changes in flow deflection/contraction reduce total head losses experienced by the main channel with an increase of the bed discordance ratio. It turns out that bed elevation discordance converts the lateral momentum from the tributary to streamwise momentum in the main channel more efficiently. (C) 2019 Hohai University. Production and hosting by Elsevier B.V

Depósitos periglaciares da depressão de Tapeus (vertente NW da Serra do Rabaçal – Maciço de Sicó; Portugal central) – análise sedimentar e morfo‐estrutural

This study aims to present calcareous conglomerate deposits, which have been taken as perigacial deposits related with slope evolution during Pleistocene cold periods. The studied deposits are located in a small tectonic depression near Tapeus. The outcrops show two main units: i) one at the bottom showing calcareous conglomerate with clast imbrication and planar structures that could indicate a northwestward palaeoflow; ii) at the top we can observe a red poligenic sandy silt deposit interbeded with small conglomeratic lenses composed by poorly sorted angular gravel elements of limestone. These are sedimentary and stratigraphic characteristics of typical deposits associated with the evolution of a slope under periglacial conditions. The preservation of the deposit is due to its location in a small depression (graben), which results from activity related with the tectonic evolution of the Sicó Massif. This also justifies the restrict geographic distribution of this deposits since they are confined to the small depression

A cyber-physical system for dynamic building evacuation

Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores. Universidade do Porto. Faculdade de Engenharia. 201

Risk aversion in financial crises

This study is designed to understand how investors risk preferences change, when faced by financial crisis. Option prices implied densities provide information about market movements and risk preferences. The data used are European call options prices on the DJIA with a time to maturity of four weeks. This paper obtains the risk aversion estimates by the extraction of options implied risk neutral densities and their translation to real world densities, applied to three crisis : Dotcom bubble in 2001; Subprime mortgage in 2008 and European sovereign debt in 2011. RND is achieved by the use of two parametric methods: mixture of lognormal densities (MLN); and generalised beta distribution of the second kind (GB2). The risk transformation procedure from RND to RWD (real world densities) is achieved by applying the power utility function. The RND empirical results imply that the GB2 method is disregarded due to inferior quality whilst the MLN produces results of higher uncertainty and expected future results of index levels corrected downward. The risk aversion estimates obtained from the RWD generation process do not present any evident pattern of evolution from a stable financial period to one of financial shock. It is also important to mention that for some periods the risk aversion reached negative values. This is a surprising result due to existent theoretical assumption of positive risk aversion. Overall, this study documents inconclusive results. Nevertheless, several important topics are left for future research. Interesting developments would consist: either replicating this study considering more expiration dates, bearing in mind that too many periods would imply an extremely generalised risk aversion estimate that would be counterproductive for achieving the objective of this paper; apply another method from the available literature; or testing the negative estimates with more sophisticated models that are beyond the focus of this paper