818 resultados para Battery chargers


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General note: Title and date provided by Bettye Lane.

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General note: Title and date provided by Bettye Lane.

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General note: Title and date provided by Bettye Lane.

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General note: Title and date provided by Bettye Lane.

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General note: Title and date provided by Bettye Lane.

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General note: Title and date provided by Bettye Lane.

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Inscriptions: Verso: [stamped] Photograph by Freda Leinwand. [463 West Street, Studio 229G, New York, NY 10014].

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Unique bimodal distributions of single crystal epitaxially grown In2O3 nanodots on silicon are shown to have excellent IR transparency greater than 87% at IR wavelengths up to 4 μm without sacrificing transparency in the visible region. These broadband antireflective nanodot dispersions are grown using a two-step metal deposition and oxidation by molecular beam epitaxy, and backscattered diffraction confirms a dominant (111) surface orientation. We detail the growth of a bimodal size distribution that facilitates good surface coverage (80%) while allowing a significant reduction in In2O3 refractive index. This unique dispersion offers excellent surface coverage and three-dimensional volumetric expansion compared to a thin film, and a step reduction in refractive index compared to bulk active materials or randomly porous composites, to more closely match the refractive index of an electrolyte, improving transparency. The (111) surface orientation of the nanodots, when fully ripened, allows minimum lattice mismatch strain between the In2O3 and the Si surface. This helps to circumvent potential interfacial weakening caused by volume contraction due to electrochemical reduction to lithium, or expansion during lithiation. Cycling under potentiodynamic conditions shows that the transparent anode of nanodots reversibly alloys lithium with good Coulombic efficiency, buffered by co-insertion into the silicon substrate. These properties could potentially lead to further development of similarly controlled dispersions of a range of other active materials to give transparent battery electrodes or materials capable of non-destructive in situ spectroscopic characterization during charging and discharging.

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Smartphones have undergone a remarkable evolution over the last few years, from simple calling devices to full fledged computing devices where multiple services and applications run concurrently. Unfortunately, battery capacity increases at much slower pace, resulting as a main bottleneck for Internet connected smartphones. Several software-based techniques have been proposed in the literature for improving the battery life. Most common techniques include data compression, packet aggregation or batch scheduling, offloading partial computations to cloud, switching OFF interfaces (e.g., WiFi or 3G/4G) periodically for short intervals etc. However, there has been no focus on eliminating the energy waste of background applications that extensively utilize smartphone resources such as CPU, memory, GPS, WiFi, 3G/4G data connection etc. In this paper, we propose an Application State Proxy (ASP) that suppresses/stops the applications on smartphones and maintains their presence on any other network device. The applications are resumed/restarted on smartphones only in case of any event, such as a new message arrival. In this paper, we present the key requirements for the ASP service and different possible architectural designs. In short, the ASP concept can significantly improve the battery life of smartphones, by reducing to maximum extent the usage of its resources due to background applications.

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Li-ion batteries have been widely used in electric vehicles, and battery internal state estimation plays an important role in the battery management system. However, it is technically challenging, in particular, for the estimation of the battery internal temperature and state-ofcharge (SOC), which are two key state variables affecting the battery performance. In this paper, a novel method is proposed for realtime simultaneous estimation of these two internal states, thus leading to a significantly improved battery model for realtime SOC estimation. To achieve this, a simplified battery thermoelectric model is firstly built, which couples a thermal submodel and an electrical submodel. The interactions between the battery thermal and electrical behaviours are captured, thus offering a comprehensive description of the battery thermal and electrical behaviour. To achieve more accurate internal state estimations, the model is trained by the simulation error minimization method, and model parameters are optimized by a hybrid optimization method combining a meta-heuristic algorithm and the least square approach. Further, timevarying model parameters under different heat dissipation conditions are considered, and a joint extended Kalman filter is used to simultaneously estimate both the battery internal states and time-varying model parameters in realtime. Experimental results based on the testing data of LiFePO4 batteries confirm the efficacy of the proposed method.

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Introdução: As funções executivas (FE) têm sido sistematicamente associadas ao funcionamento dos lobos frontais e sabemos que o declínio cognitivo se associa a piores resultados em provas que avaliam estas funções. Para além de pretendermos analisar se um teste que avalia as FE (Frontal Assessment Battery/FAB) discrimina idosos com/sem declínio cognitivo, avaliado através do Montreal Cognitive Assessment (MoCA) e se existem associações entre os resultados obtidos com a Figura Complexa de Rey-Osterreith/FCR-O (qualidade da cópia, memória de 3 e de 20 minutos) e a presença/ausência de declínio cognitivo, queremos sobretudo analisar se a qualidade e exactidão da cópia (capacidade visuo construtiva) e a memória de 3 minutos na FCR-O se associam ao resultado obtido com a FAB, dado que as duas provas estão supostamente associadas às FE e ao funcionamento dos lobos frontais avaliados com o FAB, por oposição à memória de 20 minutos (supostamente associada à área temporal, não avaliada pela FAB). Não deixámos de considerar, ainda, a associação entre as variáveis sociodemográficas e os resultados na FAB, na FCR-O e no MoCA. Metodologia: A amostra total incluiu 556 idosos (média de idades, M = 80,2; Desvio-padrão, DP = 5,23; variação = 60-100) sob resposta social em diferentes instituições do Concelho de Coimbra que aceitou responder voluntariamente (ou cujos familiares/cuidadores concederam consentimento) a uma bateria de testes (incluindo questões sociodemográficas, a FCR-O, o MoCA e a FAB). Estas variáveis foram estratificadas de acordo com a idade e escolaridade dos idosos e dicotomizadas. Para testar os nossos objetivos recorremos a diferentes sub amostras compostas pelos sujeitos que tinham resultados nas provas cujas associações queríamos testar. Resultados: De acordo com o MoCA, 59,7% dos idosos apresentavam declínio cognitivo, com 73,9% a apresentar défice executivo ligeiro, de acordo com a FAB. Quanto à FCR-O, 24,0% dos idosos apresentavam défice práxico ligeiro a moderado, 73,9% défice mnésico visual a curto prazo leve (3 minutos) e 60.9% défice mnésico visual a longo prazo leve a moderado (20 minutos). Não se verificaram associações estatisticamente significativas entre o género, estado civil e tipo de resposta social e as três variáveis centrais do estudo (MoCA, FAB e FCR-O). Quer a FAB, quer a FCR-O (as três provas: qualidade e exatidão da cópia, memória de 3 e 20 minutos) revelaram associações com a ausência/presença de declínio cognitivo. Considerando as variáveis estratificadas pela idade e escolaridade dos idosos e dicotomizadas, um teste do qui quadrado para a independência mostrou que a prova qualidade da FCR-O não estava associada ao resultado na FAB (com/sem défice executivo), ao contrário da prova memória de 3 minutos da FCR-O, que se mostrou associada a este resultado. A prova memória de 20 minutos da FCR-O voltou a não estar associada à ausência/presença de défice executivo (usando o mesmo teste). Analisando as diferentes provas da FCR-O e a FAB, sem estratificação, correlações de Spearman confirmaram as associações encontradas, mas também entre a prova qualidade da cópia da FCR-O e a FAB. Conclusão/Discussão: Os resultados seguem a literatura quanto à associação entre a prova da FCR-O memória a curto prazo/3 minutos e as funções executivas (associadas aos lobos frontais e testadas através da FAB), por oposição com a memória a longo prazo que aparece, na literatura, como mais associada/ou envolvendo à/a área temporal e que, de facto, não se mostrou associada ao resultado na FAB. Os resultados não são tão claros/consensuais no que toca à prova qualidade da cópia da FCR-O.

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Le Système Stockage de l’Énergie par Batterie ou Batterie de Stockage d’Énergie (BSE) offre de formidables atouts dans les domaines de la production, du transport, de la distribution et de la consommation d’énergie électrique. Cette technologie est notamment considérée par plusieurs opérateurs à travers le monde entier, comme un nouveau dispositif permettant d’injecter d’importantes quantités d’énergie renouvelable d’une part et d’autre part, en tant que composante essentielle aux grands réseaux électriques. De plus, d’énormes avantages peuvent être associés au déploiement de la technologie du BSE aussi bien dans les réseaux intelligents que pour la réduction de l’émission des gaz à effet de serre, la réduction des pertes marginales, l’alimentation de certains consommateurs en source d’énergie d’urgence, l’amélioration de la gestion de l’énergie, et l’accroissement de l’efficacité énergétique dans les réseaux. Cette présente thèse comprend trois étapes à savoir : l’Étape 1 - est relative à l’utilisation de la BSE en guise de réduction des pertes électriques ; l’Étape 2 - utilise la BSE comme élément de réserve tournante en vue de l’atténuation de la vulnérabilité du réseau ; et l’Étape 3 - introduit une nouvelle méthode d’amélioration des oscillations de fréquence par modulation de la puissance réactive, et l’utilisation de la BSE pour satisfaire la réserve primaire de fréquence. La première Étape, relative à l’utilisation de la BSE en vue de la réduction des pertes, est elle-même subdivisée en deux sous-étapes dont la première est consacrée à l’allocation optimale et le seconde, à l’utilisation optimale. Dans la première sous-étape, l’Algorithme génétique NSGA-II (Non-dominated Sorting Genetic Algorithm II) a été programmé dans CASIR, le Super-Ordinateur de l’IREQ, en tant qu’algorithme évolutionniste multiobjectifs, permettant d’extraire un ensemble de solutions pour un dimensionnement optimal et un emplacement adéquat des multiple unités de BSE, tout en minimisant les pertes de puissance, et en considérant en même temps la capacité totale des puissances des unités de BSE installées comme des fonctions objectives. La première sous-étape donne une réponse satisfaisante à l’allocation et résout aussi la question de la programmation/scheduling dans l’interconnexion du Québec. Dans le but de réaliser l’objectif de la seconde sous-étape, un certain nombre de solutions ont été retenues et développées/implantées durant un intervalle de temps d’une année, tout en tenant compte des paramètres (heure, capacité, rendement/efficacité, facteur de puissance) associés aux cycles de charge et de décharge de la BSE, alors que la réduction des pertes marginales et l’efficacité énergétique constituent les principaux objectifs. Quant à la seconde Étape, un nouvel indice de vulnérabilité a été introduit, formalisé et étudié ; indice qui est bien adapté aux réseaux modernes équipés de BES. L’algorithme génétique NSGA-II est de nouveau exécuté (ré-exécuté) alors que la minimisation de l’indice de vulnérabilité proposé et l’efficacité énergétique représentent les principaux objectifs. Les résultats obtenus prouvent que l’utilisation de la BSE peut, dans certains cas, éviter des pannes majeures du réseau. La troisième Étape expose un nouveau concept d’ajout d’une inertie virtuelle aux réseaux électriques, par le procédé de modulation de la puissance réactive. Il a ensuite été présenté l’utilisation de la BSE en guise de réserve primaire de fréquence. Un modèle générique de BSE, associé à l’interconnexion du Québec, a enfin été proposé dans un environnement MATLAB. Les résultats de simulations confirment la possibilité de l’utilisation des puissances active et réactive du système de la BSE en vue de la régulation de fréquence.

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Thesis (Ph.D.)--University of Washington, 2016-08