885 resultados para INTERNAL OLEFINS


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Li-ion batteries have been widely used in the EVs, and the battery thermal management is a key but challenging part of the battery management system. For EV batteries, only the battery surface temperature can be measured in real-time. However, it is the battery internal temperature that directly affects the battery performance, and large temperature difference may exist between surface and internal temperatures, especially in high power demand applications. In this paper, an online battery internal temperature estimation method is proposed based on a novel simplified thermoelectric model. The battery thermal behaviour is first described by a simplified thermal model, and battery electrical behaviour by an electric model. Then, these two models are interrelated to capture the interactions between battery thermal and electrical behaviours, thus offer a comprehensive description of the battery behaviour that is useful for battery management. Finally, based on the developed model, the battery internal temperature is estimated using an extended Kalman filter. The experimental results confirm the efficacy of the proposed method, and it can be used for online internal temperature estimation which is a key indicator for better real-time battery thermal management.

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From March 1999 to August 2000, the authors were involved in simultaneous internal and external evaluations of the social civic and political education (SCaPE) project in Northern Ireland. This project was a major initiative established by the Citizenship Foundation, the Northern Ireland Council for the Curriculum, Examination and Assessment (CCEA), and the School of Education at the University of Ulster at Coleraine. It was a 2-year project in 25 secondary schools established to design, develop, pilot and evaluate a new programme of social, civic and political education for Northern Ireland. It also aimed to serve as a model for future Citizenship curriculum developments throughout Northern Ireland and elsewhere. This paper describes the background to the project, the design and conduct of the two evaluations, and the links between them. It outlines the main conclusions of each evaluation and describes the way SCaPE has since evolved into a mainstream curriculum development project. The final part of the paper analyses the key opportunities, tensions and challenges involved in running such evaluations at a critical time in the history of Northern Ireland – a time when innovation is both necessary and controversial. It argues that, especially in such circumstances, evaluation cannot be conducted from a neutral, objective standpoint, and that it is incumbent on evaluators to recognise the emotional, personal and political commitment they make to the projects in which they are engaged.

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The need for companies to consider the environmental impact of their operations and supply chains has been highlighted in the literature. However, few studies appear to consider how companies’ progress from proactive environmental strategies implemented at the internal, operations level to proactive environmental strategies implemented at the supply chain level. This study assesses the implementation process through the lens of the natural resource-based view and dynamic capabilities perspective. First, the link between the internal strategy ‘pollution prevention’ and the supply chain strategy ‘process stewardship’ is assessed. Second, the mediating influence of the internal support processes ‘integration’ and ‘learning’ on the implementation process is considered. Data collected from a sample of 1200 UK-based food manufacturing companies is analysed using multiple regression analysis. The findings suggest that the progression to environmental efforts at the supply chain level begins with internally-based environmental efforts and that the integration of these efforts and experience gained from them are important supporting factors in this progression.

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O desenvolvimento de betões de elevado desempenho, durante o início da década de 80, revelou que este tipo particular de materiais com base em cimento é susceptível a problemas de cura. São bem conhecidos os efeitos dos fenómenos autogéneos em sistemas de elevado desempenho com base em cimento, nomeadamente a fissuração em idade jovem. Esta é, aliás vista como a maior limitação no desenvolvimento de novos materiais com durabilidade superior. Desenvolvimentos recentes de métodos de cura interna provaram ser uma boa estratégia de mitigação dos efeitos da auto-dissecação destes sistemas, onde a presente tese ganha o seu espaço no tempo. Este estudo centra-se essencialmente em sistemas de elevado desempenho com base em cimento com cura interna através de partículas superabsorventes, dando particular importância à alteração de volume em idade jovem. Da análise mais aprofundada deste método, resultam algumas limitações na sua aplicabilidade, especialmente em sistemas modificados com sílica de fumo. Conclui-se que a natureza física e química dos polímeros superabsorventes pode afectar significativamente a eficiência da cura interna. Em adição, os mecanismos de cura interna são discutidos mais profundamente, sendo que para além dos mecanismos baseados em fenómenos físicos e químicos, parecem existir efeitos mecânicos significativos. Várias técnicas foram utilizadas durante o decorrer desta investigação, com o objectivo, para além da caracterização de certas propriedades dos materiais, de perseguir as questões deixadas em aberto pela comunidade internacional, relativamente aos mecanismos que fundamentam a explicação dos fenómenos autogéneos. Como exemplo, são apresentados os estudos sobre hidratação dos sistemas para avaliação do problema numa escala microscópica, em vez de macroscópica. Uma nova técnica de cura interna emerge da investigação, baseada na utilização de agregados finos como veiculo para mitigar parcialmente a retracção autogénea. Até aqui, esta técnica não encontra par em investigação anterior, mas a extensão da cura interna ou a eficácia na mitigação baseada neste conceito encontra algumas limitações. A significância desta técnica em prevenir a micro fissuração é um aspecto que está ainda em aberto, mas pode concluir-se que os agregados finos podem ser benéficos na redução dos efeitos da restrição localizada no sistema, reduzindo o risco de micro fissuração. A utilização combinada de partículas finas de agregado e polímeros super absorventes pode ter como consequência betão sem microfissuração, ou pelo menos com nanofissuração.

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Dissertação mest., Gestão da água e da costa, Universidade do Algarve, 2007

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Some yeasts have the peculiar ability to grow in the presence of weak acids at rather low pH. These conditions are predominant in preserved foods and beverages such as fruit concentrates, juices, wine, where these yeasts are responsible for spoilage. The main preservatives currently utilized by food industries are sorbic, propionic, benzoic acids and SO2. It is usually assumed that weak acids diffuse through the plasma membrane in the undissociated form. In the cytoplasm, where the pH is higher, dissociation occurs resulting in accumulation of the lipid-insoluble anion and internal acidification. This is probably a very general mechanism of preventing microbial growth in foods.

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Tese de mestrado. Biologia (Biologia Humana e Ambiente). Universidade de Lisboa, Faculdade de Ciências, 2014

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senior thesis written for Oceanography 445

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Electricity Markets are not only a new reality but an evolving one as the involved players and rules change at a relatively high rate. Multi-agent simulation combined with Artificial Intelligence techniques may result in very helpful sophisticated tools. This paper presents a new methodology for the management of coalitions in electricity markets. This approach is tested using the multi-agent market simulator MASCEM (Multi-Agent Simulator of Competitive Electricity Markets), taking advantage of its ability to provide the means to model and simulate Virtual Power Players (VPP). VPPs are represented as coalitions of agents, with the capability of negotiating both in the market and internally, with their members in order to combine and manage their individual specific characteristics and goals, with the strategy and objectives of the VPP itself. A case study using real data from the Iberian Electricity Market is performed to validate and illustrate the proposed approach.

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L'objectif de cette étude est d'examiner la structure factorielle et la consistance interne de la TAS-20 sur un échantillon d'adolescents (n = 264), ainsi que de décrire la distribution des caractéristiques alexithymiques dans cet échantillon. La structure à trois facteurs de la TAS-20 a été confirmée par notre analyse factorielle confirmatoire. La consistance interne, mesurée à l'aide d'alpha de Cronbach, est acceptable pour le premier facteur (difficulté à identifier les sentiments (DIF)), bonne pour le second (difficulté à verbaliser les sentiments (DDF)), mais en revanche, faible pour le troisième facteur (pensées orientées vers l'extérieur (EOT)). Les résultats d'une Anova mettent en évidence une tendance linéaire indiquant que plus l'âge augmente plus le niveau d'alexithymie (score total TAS-20), la difficulté à identifier les sentiments et les pensées orientées vers l'extérieur diminuent. En ce qui concerne la prévalence de l'alexithymie, on remarque en effet que 38,5 % des adolescents de moins de 16 ans sont considérés comme alexithymiques, contre 30,1 % des 16-17 ans et 22 % des plus de 17 ans. Notre étude indique donc que la TAS-20 est un instrument adéquat pour évaluer l'alexithymie à l'adolescence, tout en suggérant quelques précautions étant donné l'aspect développemental de cette période.