Renewable Power Sources: Towards a Solar Solution

Of all of the sources of renewable energies available one can argue that the most abundant and accessible are solar power, radiation, and the energy of the tides (70 % of the earth surface is covered by water). The tidal wave energy hasn’t seen a widespread distribution yet, mainly due to the lack of interest of the governments, most of the coastal areas of the world are exclusive responsibility of the governments, thus not easily open for private venture. Considering solar power, there exist two main fields of application, land based systems and space based systems. The former systems are still in a very embryonic phase, with Japan being the lead researcher in the field, with an experimental satellite-power station to be launched before 2010. Land based systems, on the other hand, are well studied, with major research and application programs in all known forms of solar power production. Given a minimum value of incident radiation, and applying the appropriate system, (i.e. power plant type), for any given area the solar power becomes an income-producing industry.Solar energy; Renewables

Towards a Solar Solution

Of all of the sources of renewable energies available one can argue that the most abundant and accessible are solar power, radiation, and the energy of the tides (70 % of the earth surface is covered by water). The tidal wave energy hasn’t seen a widespread distribution yet, mainly due to the lack of interest of the governments, most of the coastal areas of the world are exclusive responsibility of the governments, thus not easily open for private venture. Considering solar power, there exist two main fields of application, land based systems and space based systems. The former systems are still in a very embryonic phase, with Japan being the lead researcher in the field, with an experimental satellite-power station to be launched before 2010. Land based systems, on the other hand, are well studied, with major research and application programs in all known forms of solar power production. Given a minimum value of incident radiation, and applying the appropriate system, (i.e. power plant type), for any given area the solar power becomes an income-producing industry

Étude de l'état actuel et des variations temporelles de la composition de la macrofaune benthique des substrats meubles du golfe du Lion, Méditerranée occidentale

My main aims consisted in: (1) assessing the present state and recent (1998-2010)changes in benthic macrofauna composition of the Gulf of Lions soft-bottom communities through the long term comparison of 91 stations; (2) testing the current paradigm regarding the control of those communities by climatic parameters through a 10-year monitoring of 4 stations located in the Bay of Banyuls-sur-Mer; (3) assessing the influence of Rhône River inputs on the composition of benthic macrofauna through the sampling, of 5 stations , under 4 hydrological regimes; and (4) updating the ecological quality status of Gulf of Lions benthic habitats. My results have shown the persistence ofthe same 3 communities between 1998 and 2010, the strong influence of both the NAO and the Rhône River on benthic macrofauna composition in the whole Gulf. They also showed a control of benthic macrofauna by climatic oscillations with the WeMO contributing most especially during wintert ime. Moreover, the stations most impacted by Rhône River inputs were located close to its mouth. They are negatively affected during floods and positively affected during dry periods. Lastly, Ihave updated the sensitivity/tolerance levels of Mediterranean species and confirmed the existence of major discrepancies in the results derived from different biotic indices used, although all tested indices indicated an overall stability in the ecological quality status of benthic habitats between 1998 and 2010.Mes objectifs consistaient à : (1) fournir une description de l'état actuel des communautés de la macrofaune benthique du golfe du Lion et à étudier leur variations temporelles entre 1998 et 2010 à partir de 91 stations, (2) tester le contrôle de la macrofaune par les variables climatiques à partir du suivi de 4 stations pendant 10 ans en baie de Banyuls-sur-Mer, (3) évaluer l’impact des apports du Rhône sur la macrofaune à partir de 5 stations échantillonnées dans le panache de dilution à 4 périodes hydrologiques différentes, et (4) actualiser le statut de qualité écologique des habitats benthiques du golfe. Mes résultats ont montré la conservation des communautés entre 1998 et 2010,confirmé l’influence de la NAO et du Rhône sur la composition des communautés benthiques de l’ensemble du golfe. Ils ont aussi confirmé le contrôle des descripteurs de la macrofaune par les oscillations climatiques, en particulier par la WeMO qui semble influencer le plus la macrofaune surtout en hiver. Les stations les plus impactées par les variations de débit du Rhône se situent à proximité immédiate de son embouchure. Les communautés benthiques y sont négativement affectées en périodes de crues et positivement affectées en période d’étiage estival. J'ai enfin mis à jour les niveaux de sensibilité/tolérances des espèces méditerranéennes, confirmer l’existence de disparités importantes entre les résultats dérivés de l’utilisation d’indices biotiques différents et montrer que les indices testés indiquent tous une tendance générale à la stabilité

Assessing micro-generation’s and non-linear loads’ impact in the power quality of low voltage distribution networks

Distribution networks face an increasing penetration of solar PV (photovoltaic) and small WTG (wind turbine generator) as well as other forms of micro-generation. To this scenario, one must add the dissemination of non-linear loads such as EV (electric vehicles). There is something in common between those loads and sources: the extensive use of power electronic converters with commutated switches. These devices may be a source of medium-to-high frequency harmonic distortion and their impact on the local distribution grid must be carefully assessed in order to evaluate their negative impacts on the network, on the existing conventional loads and also on other active devices. In this paper, methodologies to characterize effects such as: harmonics, network unbalances, damaging power line resonance conditions, and over/under voltages are described and applied to a real local grid configuration

Seguidor fotovoltaico : uma variação do P&O - simulação e prototipagem

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e ComputadoresEsta dissertação tenta percorrer o caminho da produção energética de fonte solar fotovoltaica (PV). Inicialmente é dada uma visão do mercado mundial da produção PV. É apresentada a teoria da célula PV e da sua associação em módulos PV. São apresentados os tipos de conversores DC-DC que se encontram normalmente associados a painéis PV assim como são mostrados os principais algoritmos de seguimento de ponto de potência máxima (MPPT). Com base nos modelos teóricos apresentados e nos módulos solares, Bangkok Solar BS-40, disponíveis no Departamento de Engenharia Electrotécnica (DEE), foi realizado o dimensionamento de um sistema PV. O sistema dimensionado foi utilizado como referência para a construção de um simulador em MatLab/Simulink. Este simulador é constituído por todos os componentes necessários para testar os diferentes algoritmos MPPT. Os componentes do simulador são: Módulo solar PV, que pode ser associado de modo a formar painéis; conversor DC-DC, tipo Flyback; seguidor MPPT com o algoritmo P&O clássico. Para confirmar se os valores de simulação obtidos para os módulos solares estavam correctos foi construído um medidor de irradiação solar que apresenta os valores em W/m2. Medindo as características do módulo solar, corrente – tensão e sabendo o valor da irradiação no mesmo instante pode verificar-se se estes se encontram de acordo com o simulado. Finalmente, com os dados obtidos na simulação foi apresentado um novo algoritmo de seguimento MPPT. Este é baseado no P&O clássico, mas com componentes que tentam ultrapassar o problema dos máximos locais e minimizar as oscilações do conversor/inversor de modo a minimizar as perdas e maximizar a produção energética

Análise do fluxo de energia vibratória entre placas retangulares simplesmente apoiadas pelo método da mobilidade /

Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico

Continuous measurements of central blood pressure during mental stress monitoring

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Detecting Semantic Conflicts using Static Analysis

Version control system tools empower developers to independently work on their development tasks. These tools also facilitate the integration of changes through merging operations, and report textual conflicts. However, when developers integrate their changes, they might encounter other types of conflicts that are not detected by current merge tools. In this paper, we focus on dynamic semantic conflicts, which occur when merging reports no textual conflicts but results in undesired interference - causing unexpected program behavior at runtime. To address this issue, we propose a technique that explores the use of static analysis to detect interference when merging contributions from two developers. We evaluate our technique using a dataset of 99 experimental units extracted from merge scenarios. The results provide evidence that our technique presents significant interference detection capability. It outperforms, in terms of F1 score and recall, previous methods that rely on dynamic analysis for detecting semantic conflicts, but these show better precision. Our technique precision is comparable to the ones observed in other studies that also leverage static analysis or use theorem proving techniques to detect semantic conflicts, albeit with significantly improved overall performance

<i>Malmgrenia louiseae</i> sp. nov., a new scale worm species (Polychaeta: Polynoidae) from southern Europe with a key to European <i>Malmgrenia</i> species

International audienceMalmgrenia louiseae sp. nov. is described from both the Western Mediterranean in the Gulf of Lions, and the Northeast Atlantic from off Portugal and the Bay of Biscay. The species was found in muddy sediments in shallow water and is possibly associated with echiurids or synaptid holothurians. Malmgrenia louiseae sp. nov. can be clearly distinguished from all other known Malmgrenia species by the presence of an infra-acicular process in addition to the supra-acicular process on the acicular lobe of the neuropodia, the lack of microtubercules on the elytra, two kinds of notochaetae (stout with blunt tip and slender with fine pointed tip), and exclusively unidentate neurochaetae. An identification key to the Northeast Atlantic and Mediterranean Malmgrenia species is provided

Assessment of PV and wind microgeneration's impact in the power quality of low and medium voltage distribution networks

Electric power systems face an ever-growing penetration (PV) and other microgeneration as well as non-linear loads such as electric vehicles. This is a common link between these : the extensive use of power electronics converters. These devices are a source of medium-to-high frequency harmonic distortion and their impact on the local distribution grid must be carefully assessed in order to evaluation possible network unbalances, demaging power line resonance conditions, transformer core saturation and overhearing