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Browsing by Issue Date, starting with "2014-12"

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  • Mechanical properties of chemically modified portuguese pinewood
    Publication . Lopes, Duarte Barroso; Mai, Carsten; Militz, Holger
    To turn wood into a construction material with enhanced properties, many methods of chemical modification have been developed in the last few decades. In this work, mechanical properties of pine wood were chemically modified, compared and evaluated. Maritime pine wood (Pinus pinaster) was modified with four chemical processes: 1,3-dimethylol-4,5- dihydroxyethyleneurea, N-methylol melamine formaldehyde, tetra-alkoxysilane and wax. The following mechanical properties were assessed experimentally: Modulus of elasticity measured statically, stiffness stabilization efficiency in different climates (30 and 87% of relative humidity), modulus of rupture, work maximum load, impact bending strength, compression, tensile and shear strength at indoor conditions (65% of relative humidity). In both types of active principle of modification, cell wall or lumen fill, no significant changes on the bending stiffness (modulus of elasticity) were found. In the remaining properties analysed significant changes in the modified wood-material took place compared to unmodified wood control: - Cell wall modification was the most effective method to achieve high stiffness stabilization efficiency (up to 60%) and also increased compression strength (up to 230%). However, modulus of rupture, tensile, shear and the impact bending strength were reduced by both resins, but in a varying extent, where the N-methylol melamine formaldehyde endured less reduction than 1,3-dimethylol-4,5-dihydroxyethyleneurea resin. In the latter, reduction up to 60% can take place. - In the lumen fill modification: tetra-alkoxysilane has no effect in the mechanical properties. Although, a slight increase in shear strength parallel to the grain was found. Wax specimens have shown a slight increase in bending strength, compression, tensile and shear strength as well as in the absorption energy capacity.
    2014-12Journal article Open access Show more
  • weCOPE: Programa cognitivo-comportamental de Intervenção em grupo na psicose
    Publication . Almeida, Raquel; Marques, António da Silva; Queirós, Cristina
    Nos últimos anos, a Terapia Cognitivo Comportamental (TCC) foi introduzida no tratamento de Psicoses, quer através de intervenções que são especificamente cognitivo-comportamentais ou como parte integrante de outras intervenções mais ecléticas.
    2014-12Book Restricted access Show more
  • Nanotechnology and antioxidant therapy: An emerging approach for neurodegenerative diseases
    Publication . Fernandes, Carlos; Oliveira, Catarina; Benfeito, Sofia; Soares, Pedro; Garrido, Jorge; Borges, Fernanda
    The efficacy, cellular uptake and specific transport of dietary antioxidants to target organs, tissues and cells remains the most important setback for their application in the treatment of oxidative-stress related disorders and in particular in neurodegenerative diseases, as brain targeting remains a still unsolved challenge. Nanotechnology based delivery systems can be a solution for the above mentioned problems, specifically in the case of targeting dietary antioxidants with neuroprotective activity. Nanotechnology-based delivery systems can protect antioxidants from degradation, improve their physicochemical drug-like properties and in turn their bioavailability. The impact of nanomedicine in the improvement of the performance of dietary antioxidants, as protective agents in oxidative- stress events, specifically through the use of drug delivery systems, is highlighted in this review as well as the type of nanomaterials regularly used for drug delivery purposes. From the data one can conclude that the research combining (dietary) antioxidants and nanotechnology, namely as a therapeutic solution for neurodegenerative diseases, is still in a very early stage. So, a huge research area remains to be explored that hopefully will yield new and effective neuroprotective therapeutic agents in a foreseeable future.
    2014-12Journal article Restricted access Show more
  • Empreendedorismo social numa IPSS: Modelo de organização e funcionamento de um lar residencial
    Publication . Santos, Carlos José de Bessa; Marques, António José Pereira da Silva
    Este projeto tem como objetivo implementar um modelo de funcionamento para um Lar Residencial de pessoas portadoras de multideficiências ou outros handicaps. Numa lógica de empreendedorismo social, como campo de ação e investigação que tem vindo a ganhar maior relevância nas diversas áreas de intervenção, em particular para as ciências sociais e humanas, pretendemos dar resposta a uma necessidade, sinalizada pela IPSS – Obra de Assistência Social da Freguesia de Sobrosa: a falta de resposta para pessoas em idade adulta, portadoras de uma deficiência/handicap, sem suporte familiar (missão social) e que necessitam de uma estrutura que lhes faculte o acesso a determinados serviços de reabilitação que gerem qualidade de vida (impacto social). Espera-se com esta estrutura potenciar e alargar as ofertas (cuidados) para os diversos públicos que apresentam necessidades específicas e que não são compatíveis com as unidades que prestam serviços a idosos (inovação social). Partimos de uma análise das necessidades e dos requisitos legais para a implementação da resposta social, definindo a estrutura, os equipamentos e os recursos humanos, fulcrais para o desenvolvimento da atividade da organização com vista à integração de 16 residentes que usufruirão de serviços especializados que lhes proporcionam qualidade de vida. O estudo de viabilidade económica e a sua sustentabilidade é fator determinante para o sucesso desta resposta empreendedora. Com a verificação da funcionalidade desta iniciativa, após uma medição dos indicadores de resultados alcançados, da análise da eficiência dos processos, da viabilidade económica, demonstramos o potencial de crescimento ou de replicação deste projeto noutras instituições ou contextos.
    2014-12Master thesis Open access Show more
  • Data Mining Approach to support the Generation of Realistic Scenarios for Multi-Agent simulation of Electricity Markets
    Publication . Teixeira, Brígida; Silva, Francisco; Pinto, Tiago; Praça, Isabel; Santos, Gabriel; Vale, Zita
    This paper presents the Realistic Scenarios Generator (RealScen), a tool that processes data from real electricity markets to generate realistic scenarios that enable the modeling of electricity market players’ characteristics and strategic behavior. The proposed tool provides significant advantages to the decision making process in an electricity market environment, especially when coupled with a multi-agent electricity markets simulator. The generation of realistic scenarios is performed using mechanisms for intelligent data analysis, which are based on artificial intelligence and data mining algorithms. These techniques allow the study of realistic scenarios, adapted to the existing markets, and improve the representation of market entities as software agents, enabling a detailed modeling of their profiles and strategies. This work contributes significantly to the understanding of the interactions between the entities acting in electricity markets by increasing the capability and realism of market simulations.
    2014-12Conference object Restricted access Show more
  • Sistema de Gestão Técnica Aplicado aos Sistemas de Rega
    Publication . Silva, Ricardo Miguel Borges Sá e; Santos, Adriano Almeida
    A cidade do Porto é uma das regiões do país onde é importante uma gestão sustentável e integrada dos recursos hídricos. A (re) utilização de água surge neste contexto como uma possível resposta na sua utilização como um recurso hídrico passível de ser usado beneficamente, permitindo a poupança de fontes de água convencionais e aumentando a disponibilidade dos recursos hídricos existentes para finalidades que requerem padrões de qualidade mais exigentes. O potencial desta prática no nosso país é enorme, considerando que o volume de água tratada descarregada no ano 2000 era suficiente para suprir 10% das necessidades em água para rega num ano seco, sem necessidade de armazenamento sazonal. Por outro lado, um sistema de rega, quando devidamente projetado e funcionando adequadamente, permite que a água seja aplicada com um caudal, duração e frequência que maximizam o consumo da água e nutrientes pela planta. Este projeto consiste no desenvolvimento de um Sistema de Gestão Técnica para o controlo do sistema de rega dos jardins do ISEP – Instituto Politécnico de Engenharia do Porto com recurso a um autómato programável (PLC). Pretende-se otimizar os consumos energéticos do sistema de rega tendo em conta os parâmetros de humidade, temperatura e velocidade do vento característicos do local a regar. Outros dos objetivos é controlar o processo de enchimento e de rega. Esta operação consiste no controlo das bombas e respetivos débitos e conhecimento dos caudais necessários. Pretende-se, igualmente, definir e colocar em marcha todo o equipamento necessário para a realização do projeto. Os dados coletados devem ser tratados de tal modo que possam ser realizadas análises diárias, mensais e/ou anuais. Neste trabalho foram efetuados os cálculos de dimensionamentos relativamente às necessidades hídricas da planta e necessidades de rega, entre outros.
    2014-12Master thesis Open access Show more
  • Short-term Wind Speed Forecasting using Support Vector Machines
    Publication . Pinto, Tiago; Ramos, Sérgio; Sousa, Tiago; Vale, Zita
    Wind speed forecasting has been becoming an important field of research to support the electricity industry mainly due to the increasing use of distributed energy sources, largely based on renewable sources. This type of electricity generation is highly dependent on the weather conditions variability, particularly the variability of the wind speed. Therefore, accurate wind power forecasting models are required to the operation and planning of wind plants and power systems. A Support Vector Machines (SVM) model for short-term wind speed is proposed and its performance is evaluated and compared with several artificial neural network (ANN) based approaches. A case study based on a real database regarding 3 years for predicting wind speed at 5 minutes intervals is presented.
    2014-12Conference object Restricted access Show more
  • Diffusion-weighted breast imaging at 3 T: Preliminary experience
    Publication . Nogueira, Luisa; Brandão, S.; Matos, E.; Nunes, R. G.; Ferreira, H. A.; Loureiro, J.; Ramos, I.
    To evaluate the performance of diffusion-weighted imaging (DWI) at 3 T for the detection and characterization of breast lesions.
    2014-12Journal article Restricted access Show more
  • A New Heuristic Providing an Effective Initial Solution for a Simulated Annealing approach to Energy Resource Scheduling in Smart Grids
    Publication . Sousa, Tiago; Morais, Hugo; Castro, Rui; Vale, Zita
    An intensive use of dispersed energy resources is expected for future power systems, including distributed generation, especially based on renewable sources, and electric vehicles. The system operation methods and tool must be adapted to the increased complexity, especially the optimal resource scheduling problem. Therefore, the use of metaheuristics is required to obtain good solutions in a reasonable amount of time. This paper proposes two new heuristics, called naive electric vehicles charge and discharge allocation and generation tournament based on cost, developed to obtain an initial solution to be used in the energy resource scheduling methodology based on simulated annealing previously developed by the authors. The case study considers two scenarios with 1000 and 2000 electric vehicles connected in a distribution network. The proposed heuristics are compared with a deterministic approach and presenting a very small error concerning the objective function with a low execution time for the scenario with 2000 vehicles.
    2014-12Conference object Restricted access Show more
  • A Learning Algorithm and System Approach to Address Exceptional Events in Domestic Consumption Management
    Publication . Gomes, Luis; Fernandes, Filipe; Vale, Zita; Faria, Pedro; Ramos, Carlos
    The integration of the Smart Grid concept into the electric grid brings to the need for an active participation of small and medium players. This active participation can be achieved using decentralized decisions, in which the end consumer can manage loads regarding the Smart Grid needs. The management of loads must handle the users’ preferences, wills and needs. However, the users’ preferences, wills and needs can suffer changes when faced with exceptional events. This paper proposes the integration of exceptional events into the SCADA House Intelligent Management (SHIM) system developed by the authors, to handle machine learning issues in the domestic consumption context. An illustrative application and learning case study is provided in this paper.
    2014-12Conference object Restricted access Show more