488 research outputs found

    Simulação numérica do comportamento de elementos estruturais em concreto e argamasa armada pelo emprego de um modelo de dano

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    Este trabalho apresenta um estudo preliminar sobre a resposta de um modelo constitutivo a dano, do tipo isótropo, na análise do comportamento nao linear de elementos estruturais (vigas e placas) em concreto e argamassa armada. Os resultados obtidos coniprovam a boa performance do modelo empregado e asseguram urna continuidade para os estudos aqui iniciados.Peer Reviewe

    Simulação numérica do comportamento de elementos estruturais em concreto e argamasa armada pelo emprego de um modelo de dano

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    Este trabalho apresenta um estudo preliminar sobre a resposta de um modelo constitutivo a dano, do tipo isótropo, na análise do comportamento nao linear de elementos estruturais (vigas e placas) em concreto e argamassa armada. Os resultados obtidos coniprovam a boa performance do modelo empregado e asseguram urna continuidade para os estudos aqui iniciados.Peer Reviewe

    The Framework “Iberian Massif Landscape and Fluvial Network” in the scope of the Portuguese Geological Heritage Inventory

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    A diversidade de aspectos do relevo e da drenagem fluvial no Maciço Ibérico justificaram a definição de 5 temas dominantes, agrupados numa categoria temática, com vista ao processo de inventariação de geossítios de valor científico e relevância internacional ou nacional, no âmbito da inventariação do património geológico português em curso. Os temas sucintamente caracterizados são: Macro-geoformas residuais, Geoformas graníticas, Geoformas tectónicas, Sedimentos cenozóicos e Geoformas fluviais. Para cada tema foram definidos alguns subtemas e áreas-chave para a selecção dos geossítios.Five themes were defined taking into account the diversity of geomorphological elements in the Portuguese Iberian Massif. These themes are grouped under a geological framework established to help the selection of geosites with scientific value of national or international significance, under the scope of the ongoing inventory of the Portuguese geological heritage. These themes are: Residual macro-landforms, Granite landforms, Tectonic landforms, Cenozoic sediments, and Fluvial landforms. For each theme, some sub-themes were defined as well as key-areas for the selection of geosites.Este trabalho é apoiado pela Fundação para a Ciência e a Tecnologia, através do financiamento plurianual do CGUP e do projecto de investigação “Identificação, caracterização e conservação do património geológico: uma estratégia de geoconservação para Portugal” (PTDC/CTE-GEX/64966/2006).info:eu-repo/semantics/publishedVersio

    A platform to support civil protection applications on the GRID

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    The CROSS-Fire is a Portuguese NGI funded project focus-ing on the development of a grid-based risk management decision support system for the Civil Protection (CP), using forest fires as the main case study. The project defines a general approach for the development of a CP application by defining an architecture that integrates three main layers: the CROSS-Fire Platform and two external infrastructures: a Spatial Data Infrastructure (SDI) and the GRID. The CROSS-Fire Platform is defined and implemented as a set of WPS algorithms dealing with most of the functionalities of its three components: Business Logic, Grid Services and Geospatial services. The present work stresses the relevance of standards adoption: OGC-WS WCS/WFS/WMS/WPS, to exploit/enable geospatial services for data access processing, and OGC-SWE SOS to address other CP data sources, such as meteorological station networks (MSN) or satellites. The adoption of a Web Services (WS) approach allows integrating easily with existing systems typically based on WS technologies. We also present CFS, a grid user interface SDI based client, compliant with OGC and EU INSPIRE directives which allows decision makers to access the spatial data infrastructure, to launch simulations on the grid and visualize the fire propagation simulations.Fundação para a Ciência e a Tecnologia (FCT

    CROSS-Fire : a risk management decision support system on the Grid

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    The CROSS-Fire project aims to develop a grid-based risk management decision support system for the Civil Protection (CP) authorities, using forest fires as the main case study and FireStation as a standalone CAD application to simulate the fire spread over complex topography. CROSS-Fire approach is based in an architecture that includes: information models, encodings, and metadata that represent the scientific knowledge associated to FireStation execution models and standards to enable the discovery and access of Web services, data repository, sensor networks and data processing facilities. To achieve the desired integration of information and services we use: i) EGEE to provide raw technological capability provision, including data management and storage, access to meta-data data bases and high-performance computing and ii) a Geospatial Information Infrastructure based on OCG-WS and SWE Web services to provide the access and management of remote geospatial data and virtualized sensor networks. This article, stresses the relevance of standards adoption of OGC-WS by describing the work that is been done to provide G-FireStation with: i) a standard-based SDI layer, based on Geoserver to exploit/enable geospatial services for data access/processing and ii) a 52N’s implementation of a OGC-SWE compatible layer, to address sensors CP data sources, such as meteorological stations data and satellite images and iii) the development of G-FireStation graphical user interface to access the platform facilities. The core of the CROSS-Fire Platform is a WPS 52North OGC standard layer divided into three interoperable components, respectively, the CROSS-Fire Business Logic, the Grid Services and Geospatial Services. WPS serves as an interface to a wide range of distributed computing resources provides the mechanism to access the grid facilities for processing and data management and including all the algorithms, calculation, or model that operates on spatially referenced data, also mediating all the communication with the portal and other GUI clients. The G-FireStation user interface that is currently under development is an open-source desktop with GIS and CAD capabilities that exploits an SDI client complying with OGC-WS and EU INSPIRE directives. It provides facilities to locate and access the spatial data infrastructure and to visualize the fire propagation, based on the native facilities of gvSig, it was also extended to support a OGC WPS client that mediate all the interactions with the core WPS service layer.Fundação para a Ciência e a Tecnologia (FCT

    Water quantity and quality under future climate and societal scenarios: a basin-wide approach applied to the Sorraia river, Portugal

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    Water resources are impacted by several stressors like over-population and over consumption that compromises their availability. These stressors are expected to progressively intensify due to climate change in most regions of the world, with direct impact on watersheds and river systems. This study investigates the effect of different watershed pressure scenarios due to climate change in the hydrological regime of the Sorraia River basin, Portugal. This catchment includes one of the largest irrigated areas in the country, thus being strongly influenced by anthropogenic activities, associated to hydrological (irrigation, flow regulation, damming) and nutrient stressors. The SoilWater Assessment Tool has been used to simulate water flow and nutrient dynamics in the watershed while considering inputs from two climate models and three societal scenarios. Results have shown that the predicted rainfall reductions will have a significant impact on river flow and nutrient concentrations when compared to baseline conditions. River flow will expectably decrease by 75%, while nitrogen and phosphorus concentrations in river water will expectably increase by 500% and 200%, respectively. These differences are more evident for storylines that consider increasing pressures such as population growth and agricultural expansion marked with unsustainable practices and increased reliance on technology. The results of this study indicate a possible future outcome and provide effective guidelines for the formulation of water management policies to counter the impacts of climate change and corresponding environmental pressures in the Sorraia River basininfo:eu-repo/semantics/publishedVersio

    Evaluation of the trophic status in a Mediterranean reservoir under climate change: an integrated modelling approach

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    This study describes an integrated modelling approach to better understand the trophic status of the Montargil reservoir (southern Portugal) under climate change scenarios. The SWAT and CE-QUAL-W2 models were applied to the basin and reservoir, respectively, for simulating water and nutrient dynamics while considering one climatic scenario and two decadal timelines (2025–2034 and 2055–2064). Model simulations showed that the dissolved oxygen concentration in the reservoir’s hypolimnion is expected to decrease by 60% in both decadal timelines, while the chlorophyll-a concentration in the reservoir’s epiliminion is expected to increase by 25%. The total phosphorus concentration (TP) is predicted to increase in the water column surface by 63% and in the hypolimion by 90% during the 2030 timeline. These results are even more severe during the 2060 timeline. Under this climate change scenario, the reservoir showed a eutrophic state during 70–80% of both timelines. Even considering measures that involve decreases in 30 to 35% of water use, the eutrophic state is not expected to improveinfo:eu-repo/semantics/publishedVersio

    Retina and Choroid of Diabetic Patients Without Observed Retinal Vascular Changes: A Longitudinal Study

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    PURPOSE: To identify changes in choroidal thickness (CT) and all retinal layers of diabetic patients without diabetic retinopathy (DR) after 1 year of follow-up. DESIGN: Prospective observational cohort study. METHODS: Overall, 125 diabetic patients without DR were included. Two visits were scheduled: the first visit (V1) and a second visit after 12 months (V2). At both visits, patients received a complete ophthalmologic evaluation that included OCT. Each retinal layer thickness was calculated for 9 ETDRS sectors, and CT was measured at 13 locations. Generalized linear mixed-effects models were used. RESULTS: Of the 125 patients, 103 completed the study, and 9 of the 103 developed DR (8.7%). CT was significantly higher at V2 than at V1, with an average value of 10-17 μm at almost half the locations (500, 1000, and 1500 μm temporal; 500 and 1000 μm nasal; and 1000 μm superior to the fovea) (P < .001-.003). The thicknesses of the ganglion cell layer (I3 and N6 sectors), inner plexiform layer (S6 and N6 sectors), inner nuclear layer (T6 and N6 sectors), and outer plexiform layer (S6 sector), as well as the overall retinal thickness (RT) (S3, N3, I3, S6, and T6 sectors), were decreased at V2 (P < .001). Visible retinopathy was negatively associated with overall RT (central, S3, T3, I3, and N3 sectors, P = .004-.024) and the thickness of the ONL (T6 and I6 sectors, P = .007 and P = .009) and photoreceptor layer (N6 sector, P = .038). The presence of DR decreased the overall RT by 13.04-16.63 μm. CONCLUSIONS: Diabetic patients without DR showed a thicker choroid and a thinner retina, particularly in inner layers, after 1 year of follow-up. These structural changes may correspond to the early neurodegenerative phase of DR.info:eu-repo/semantics/publishedVersio
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