Browsing by Issue Date, starting with "2017-06"
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- A new real time Lyapunov based controller for power quality improvement in unified power flow controllers using direct matrix convertersPublication . Monteiro, Joaquim; Pinto, Sonia; Martins, Aranzazu Delegado; Silva, José FernandoThis paper proposes a Direct Matrix Converter operating as a Unified Power Flow Controller (DMC-UPFC) with an advanced control method for UPFC, based on the Lyapunov direct method, presenting good results in power quality assessment. This control method is used for real-time calculation of the appropriate matrix switching state, determining which switching state should be applied in the following sampling period. The control strategy takes into account active and reactive power flow references to choose the vector converter closest to the optimum. Theoretical principles for this new real-time vector modulation and control applied to the DMC-UPFC with input filter are established. The method needs DMC-UPFC dynamic equations to be solved just once in each control cycle, to find the required optimum vector, in contrast to similar control methods that need 27 vector estimations per control cycle. The designed controller's performance was evaluated using Matlab/Simulink software. Controllers were also implemented using a digital signal processing (DSP) system and matrix hardware. Simulation and experimental results show decoupled transmission line active (P) and reactive (Q) power control with zero theoretical error tracking and fast response. Output currents and voltages show small ripple and low harmonic content.
- Visão e perspectivas do projecto GermInArte: A qualificação de recursos humanos e profissionais nos cuidados prestados na infância como alicerce para o desenvolvimento social e humanoPublication . Rodrigues, Helena; Rodrigues, Paulo Maria; Rodrigues, Paulo FerreiraO projecto GermInArte — TransFormação Artística para o Desenvolvimento Social e Humano a partir da Infância1 é um projecto artístico e educativo que tem como finalidades a concepção de boas práticas de formação e a qualificação de recursos humanos interventivos no âmbito do desenvolvimento social e humano a partir da primeira infância.
- Carbon nanodots from olive mill wastewater: a sustainable routePublication . Sousa, D. A.; Costa, Alexandra; Alexandre, M. R.; Prata, José VirgílioOlive oils are obtained from the fruit of the olive tree (Olea europaea L.) by combined mechanical and physical operations. Portugal has a significant production of olive oil (76 k tonnes/year over the last 5 years, 2010-2015) [1]. Olive oil is typically obtained by two main processes: batch press and continuous centrifugation. Depending on the particular process used, 200-1600 L of olive mill wastewater (OMWW) is produced per tonne of processed olives. Taken the lowest of these values, an estimate points to around 15 million L of OMWW may be produced each year in Portugal. The OMWW exhibits very low biodegradability parameters which pose serious issues for its treatment. Sustainable production of high-valued carbon materials from industrial lowvalued and problematic wastes is particularly appealing and highly desirable.
- Vantagens e desvantagens do ensino das técnicas de quatro baquetas para instrumentos de lâminas nas escolas de música portuguesasPublication . Quintas, Rui Miguel Janes; Buckley, Charles Richard; Quintas, Élia JanesResumo I - Prática Pedagógica - O estágio pedagógico, objectivo inerente a esta importante secção, realizou-se no Conservatório de Música da Metropolitana da AMEC | Metropolitana, em Lisboa. Inicialmente caracteriza-se esta estrutura quanto à história, estrutura e objetivos pedagógicos. O estudo da população escolar e a sua distribuição abordou-se de forma aprofundada, dissecando matematicamente a distribuição da mesma pelos diferentes cursos disponibilizados pela escola, pela faixa etária dos alunos e pelo plano curricular onde os mesmos se inserem. Seguidamente optou-se por uma caracterização descritiva dos alunos integrantes da amostra, sob a qual o trabalho se realizou, expondo tanto os seus níveis musicais como a suas situações curricular e sociológica. Analisaram-se as suas perspetivas e motivações, contrastando-as com a abordagem do pensamento epistemológico. Na parte orientada para a pedagogia desenvolvida incide-se substancialmente nos níveis metacognitivos e motivacionais intrínsecos de cada aluno, tal como nos objetivos, metas e estratégias previamente delineados de forma ao melhor desempenho destes. O capítulo seguinte relaciona-se com a análise crítica da atividade docente. Apresenta-se primeiro, uma exposição metodológica do trabalho desenvolvido pelos alunos ao longo dos três períodos letivos, utilizando-se uma forma pormenorizada para a fácil compreensão da situação curricular dos alunos. Posteriormente optou-se por apresentar uma crítica analítica, abordando de sobremaneira a ótica tanto do aluno como do mestrando na apresentação e resultados da pedagogia aplicada, demonstrando-se a eficácia dos métodos pedagógicos escolhidos, assim como a recetividade e assimilação dos mesmos por partes dos alunos. Conclui-se, depois de uma sustentada introspeção, que a realização deste relatório e das ações que lhe estão subjacentes permitiu a revisão e a consistência de conceitos didáticos anteriormente assimilados, assim como a melhoria da postura na futura atividade docente. A autoavaliação inerente ao trabalho desenvolvido constituiu-se como alavanca na melhoria continuada do papel de professor e na capacidade de análise de cada aluno, permitindo uma reflexão individual e centrada nas suas características intelectuais e psicomotoras do desenvolvimento.
- Communication with citizens in the first EU citizen observatories experiencesPublication . Montargil, Filipe; Santos, VitorThis paper presents the emerging concept and reality of Citizen Observatories (COs). We offer a brief overview of its opportunities and its areas of application and discuss some central elements of the first generation of Citizen Observatories pilot projects’ funded by the European Union, between 2012 and 2016, in what regards communication with citizens. The concept of CO implies, according to the existing definitions, an open and shared information system dedicated to the collection of data on the environment and natural resources, using ICT, and the volunteer participation of individuals in data collection. The EU has adopted a more specific concept of CO in the projects funded, so that the resulting information complements existing earth observation systems (including the European Copernicus satellite program). In the 2012 In the 2012—2016 period five CO projects have been funded by the EU, covering different areas: natural waters monitoring, odour monitoring, air quality monitoring, flood risk management and a platform for citizen science surveys. These COs allowed to develop and test the concept’s implementation. According to our analysis, we can identify different communication strategies with citizens, in these projects, ranging from all-inclusive strategies (using websites, Android and IOS apps, both to collect and disseminate information) to more focused communication strategies. Besides this, awareness is also a critical issue for COs, since they need to attract a relevant number of citizens in order to justify their existence and to thrive. Most projects make extensive use of social networking sites (SNS), including Facebook, Twitter, YouTube, LinkedIn, Google+ and Slideshare. Despite this use, however, it cannot yet be considered that COs reach a vast number of citizens. Rather, the number of citizens involved was very limited, in the first generation of pilot projects. But societal challenges may assume a more relevant role in the following stages, with the projects that will be developed between 2016 and 2020.
- Occupational exposure to fungi and mycotoxins in cork industry: an exploratory studyPublication . Viegas, Susana; Osteresch, Bernd; Hövelmann, Yannick; Faria, Tiago; Gomes, Anita Quintal; Cramer, Benedikt; Viegas, Carla; Humpf, Hans-UlrichCork oak is the second most dominant forest species in Portugal and makes this country the work leader in cork export. This type of industry has already been associated with occupational exposure to several fungal species, most commonly with Penicillium globrum (belonging to Penicillium section Aspergilloides) and Chrysonilia sitophila. However, occupational exposure to mycotoxins has never been studied. Here we describe an exploratory work developed in a cork industry located in Portugal aiming at assessing exposure to fungi and mycotoxins.
- The solid solutions (Per)(2)[PtxAu(1-x)(mnt)(2)]; alloying para-and diamagnetic anions in two-chain compoundsPublication . Matos, Manuel; Bonfait, Gregoire; Santos, Isabel C.; Afonso, Monica L.; Henriques, Rui T.; Almeida, ManuelThe alpha-(Per)(2)[M(mnt)(2)] compounds with M = Pt and Au are isostructural two-chain solids that in addition to partially oxidized conducting perylene chains also contain anionic chains that can be either paramagnetic in the case of M = Pt or diamagnetic for M = Au. The electrical transport and magnetic properties of the solid solutions (Per)(2)[Pt-x-Au(1-x)(mnt)(2)] were investigated. The incorporation of paramagnetic [Pt(mnt)(2)] impurities in the diamagnetic chains, and the effect of breaking the paramagnetic chains with diamagnetic centers for the low and high Pt range of concentrations were respectively probed. In the low Pt concentration range, there is a fast decrease of the metal-to-insulator transition from 12.4 K in the pure Au compound to 9.7 K for x = 0.1 comparable to the 8.1 K in the pure Pt compound. In the range x = 0.5-0.95, only beta-phase crystals could be obtained. The spin-Peierls transition of the pure Pt compound, simultaneous with metal-to-insulator (Peierls) transition is still present for 2% of diamagnetic impurities (x = 0.98) with transition temperature barely affected. Single crystal X-ray diffraction data obtained a high-quality structural refinement of the alpha- phase of the Au and Pt compounds. The beta-phase structure was found to be composed of ordered layers with segregated donors and anion stacks, which alternate with disordered layers. The semiconducting properties of the beta-phase are due to the disorder localization effects.
- A low fermentable oligo-di-mono-saccharides and polyols (FODMAP) diet is a balanced therapy for fibromyalgia with nutritional and symptomatic benefitsPublication . Marum, Ana Paula; Moreira, Cátia; Tomas-Carus, Pablo; Saraiva, Fernando; Guerreiro, Catarina SousaIntroduction: Fibromyalgia is a chronic rheumatic disease producing widespread pain, associated to a major comorbidity -irritable bowel syndrome. Low FODMAPS diet (low fermentable oligo-di-mono-saccharides and polyols diet) has been effective in controlling irritable bowel syndrome symptoms. Overweight is an aggravating factor for fibromyalgia. We studied effects of low fermentable oligo-di-mono-saccharides and polyols diets on fibromyalgia symptoms and weight status. Methods: A longitudinal study was performed on 38 fibromyalgia patients using a four-week, repeated assessment as follow: M1 = first assessments/presentation of individual low fermentable oligo-di-mono-saccharides and polyols diet; M2 = second assessments/reintroduction of FODMAPs; M3 = final assessments/nutritional counseling. The assessment instruments applied were: Fibromyalgia Survey Questionnaire (FSQ); Severity Score System (IBS-SSS); visual analogic scale (VAS). Body mass-index/composition and waist circumference (WC) were also measured. Daily macro-micronutrients and FODMAP intake were quantified at each moment of the study. Results: The studied cohort was 37% overweight, 34% obese (average body-mass-index 27.4 ± 4.6; excess fat mass 39.4 ± 7%). Weight, body-mass-index and waist circumference decreased significantly (p < 0.01) with low fermentable oligo-di-mono-saccharides and polyols diet, but no significant effect on body composition was observed. All fibromyalgia symptoms, including somatic pain, declined significantly post-LFD (p < 0.01); as well for severity of fibromyalgia [Fibromyalgia survey questionnaire: M1 = 21.8; M2 = 16.9; M3 = 17.0 (p < 0.01)]. The intake of essential nutrients (fiber, calcium, magnesium and vitamin D) showed no significant difference. The significant reduction in FODMAP intake (M1 = 24.4 g; M2 = 2.6g; p < 0.01) reflected the "Diet adherence" (85%). "Satisfaction with improvement of symptoms" (76%), showed correlating with "diet adherence" (r = 0.65; p < 0.01). Conclusions: Results are highly encouraging, showing low fermentable oligo-di-mono-saccharides and polyols diets as a nutritionally balanced approach, contributing to weight loss and reducing the severity of FM fibromyalgia symptoms.
- Volatility spillovers in the Iberian electricity marketPublication . Vicente, João; Martins, Ana Alexandra; Lagarto, João; Sousa, Jorge A. M.With the globalization of the world economy, the relationships between commodities, financial and other markets are relevant. Although the electricity market is a more recent kind of market, it is still related with other markets, such as, commodities markets (natural gas, coal, oil), and carbon emissions markets. In this work, we propose to study the interconnections between the day-ahead Iberian electricity market (MIBEL) and the commodities markets, as well as, the carbon emissions markets between 2010 and 2016. To achieve this purpose, we use the Diebold-Yilmaz framework, which proposes measures of the interdependence of returns and volatilities through variance decomposition of forecasted error variances in a generalized vector autoregressive model. Results show that the markets that had a higher influence in MIBEL in the analyzed period were the TTF and Zeebrugge natural gas markets and the markets that MIBEL most influenced were the Coal (API2) and CER market.
- Estrutura financeira das concessões: análise comparativa entre concessões públicas e concessões privadas entre 2010 e 2014Publication . Vieira, Manuel; Breia, Arménio FernandesO objetivo deste estudo é analisar um setor primordial para o nosso País e para a população em geral – o setor das Águas. A estrutura de gastos, o endividamento, a diferenciação entre a gestão privada e a gestão pública das concessões e a influência nos seus resultados são temas de extrema importância para o futuro, não apenas para a sustentabilidade do próprio setor, como também para todos os consumidores. Esta investigação tem como base uma revisão bibliográfica, fundamentalmente sobre a origem das concessões no nosso País, a sua comparação com outro método de gestão em voga – as parcerias público-privadas. A revisão bibliográfica incide igualmente na análise utilizada para a comparação das empresas em estudo face às suas diferenças. Foi realizado um estudo de caso a três concessões sob a gestão publica e três sob a gestão privada, tentando-se identificar as principais diferenças. A resposta a perguntas tais como “O setor das Águas em Portugal é sustentável?” ou “Qual dos modelos analisados (Concessão privada ou concessão pública) obtem melhores resultados?” foram o principal foco. No final deste trabalho verificámos que o setor das Águas pode ser auto sustentável. Não se podendo afirmar inequivocamente qual das concessões é o melhor tipo de gestão, mas podendo-se verificar que a complementariedade das duas seria o melhor dos dois mundos.