Browsing by Issue Date, starting with "2012-01"
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- O poder encantatório das crianças performersPublication . Fradique, Teresa
- Seismic design of RC frames retrofitted with concentric steel bracesPublication . Sousa, Romain; Castro, J. MiguelThe implementation in Europe of a new seismic design code (Eurocode 8) will impose strict performance requirements to building structures. This will result in a significant number of existing reinforced concrete structures showing inadequate seismic resistance and hence requiring intervention. One of the available retrofitting techniques consists of inserting steel braces in the original RC structure. In spite of the advantages of using this retrofitting approach, the adoption of this technique is still limited due to the lack of seismic design rules. The interaction between the steel braces and the RC members turns the design in an intricate task. The main goal of the research presented in this paper was to develop a simple yet reliable design procedure that can promote the retrofitting of reinforced concrete frames with steel braces. The proposed method is based on displacements and accounts for the interaction of the steel elements on the deformation capacity of the RC members. To this end, nonlinear static and time-history analysis of reinforced concrete structures strengthened with concentric steel braces have been performed with the objective of deriving a number of key parameters (displacement profiles, yield drifts and target displacements) which are essential for the application of the new design procedure. The paper closes with an application of the proposed method to a RC structure with inadequate seismic resistance. The performance assessment of the retrofitted structure, carried out with nonlinear static analysis, confirms the validity of the design procedure and demonstrates the merits of adopting displacement-based seismic design approaches.
- Radio Frequency Numerical Simulation Techniques Based on Multirate Runge‐Kutta SchemesPublication . Oliveira, Jorge F.; Pedro, José C.; Oluwole D. MakindeElectronic circuit simulation, especially for radio frequency (RF) and microwave telecommunications, is being challenged by increasingly complex applications presenting signals of very different nature and evolving on widely separated time scales. In this paper, we will briefly review some recently developed ways to address these challenges, by describing some advanced numerical simulation techniques based on multirate Runge‐Kutta schemes, which operate in the one‐dimensional time and also within multidimensional frameworks.
- La insolvencia de los consumidores en el derecho positivo español y portugués: retrato de una reforma inacabadaPublication . Conceição, Ana Filipa; Frade, Catarina Ferreira; Ávila de la Torre, Alfredo
- Water quality in Lis river, PortugalPublication . Vieira, Judite; Fonseca, André; Vilar, Vítor J. P.; Boaventura, Rui A. R.; Botelho, Cidália M. S.In the past 30 years, the Lis river basin has been subjected to constant ecological disasters mainly due to piggery untreated wastewater discharges. The aim of this study was to evaluate the effect of existing domestic, agricultural, and industrial activities on the water quality, and to propose a watershed plan to protect and manage surface water resources within the Lis river basin. For this purpose, 16 monitoring stations have been strategically selected along the Lis river stretch and its main tributaries to evaluate the water quality in six different sampling periods (2003- 2006). All samples were characterized in terms of organic material, nutrients, chlorophyll, and pathogenic bacteria. Generally, the Lis river presents poor water quality, according to environmental quality standards for surface water, principally in terms of dissolved oxygen, biochemical oxygen demand, total nitrogen, and fecal coliform, which can be associated mainly with the contamination source from pig-breeding farms. © Springer Science+Business Media B.V. 2012.
- Formação de docentes no Ensino Superior: a experiência do Instituto Politécnico de Leiria, PortugalPublication . Seco, Graça; Pereira, Ana Patrícia; Alves, Sandra; Filipe, Luís; Duarte, Ana Lúcia