7,241 research outputs found

    Improved voltage control of the electric vehicle operating as UPS in smart homes

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    As a contribution for sustainability, electric vehicles (EVs) are seen as one of the most effective influences in the transport sector. As complement to the challenges that entails the EVs integration into the grid considering the bidirectional operation (grid-to-vehicle and vehicle-to-grid), there are new concepts associated with the EV operation integrating various benefits for smart homes. In this sense, this paper proposes an improved voltage control of the EV operating as uninterruptible power supply (UPS) in smart homes. With the EV plugged-in into the smart home, it can act as an off-line UPS protecting the electrical appliances from power grid outages. Throughout the paper, the foremost advantages of the proposed voltage control strategy are comprehensively emphasized, establishing a comparison with the classical approach. Aiming to offer a sinusoidal voltage for linear and nonlinear electrical appliances, a pulse-width modulation with a multi-loop control scheme is used. A Kalman filter is used for decreasing significantly the time of detecting power outages and, consequently, the transition for the UPS mode. The experimental validation was executed with a bidirectional charger containing a double stage power conversion (an ac-dc interfacing the grid-side and a dc-dc interfacing the batteries- side) and a digital stage. The computer simulations and the acquired experimental results validate the proposed strategy in different conditions of operation.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation – COMPETE 2020 Programme, and by National Funds through the Portuguese funding agency, FCT – Fundação para a Ciência e a Tecnologia, within project SAICTPAC/0004/2015 – POCI – 01–0145–FEDER–016434. This work is part of the FCT project 0302836 NORTE-01-0145-FEDER-030283.info:eu-repo/semantics/publishedVersio

    Synthesis and properties of Co-doped titanate nanotubes and their optical sensitization with methylene blue

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    Here we report on a novel chemical route to synthesize homogenous cobalt doped titanate nanotubes (CoTNT), using an amorphous Co-doped precursor. The influence of the synthesis temperature, autoclave dwell time and metal doping on the structural and microstructural as well as on the optical properties of the synthesized titanate nanotubes is studied and discussed. The optical band gaps of the CoTNT samples are red shifted in comparison with the values determined for the undoped samples, such red shifts bringing the absorption edge of the CoTNT samples into the visible region. CoTNT materials also demonstrate particular high adsorption ability for methylene blue, the amount of the adsorbed dye being higher than the one predictable for a monolayer formation. This suggests the possibility of intercalation of the dye molecule between the TiO6 layers of the TNT structure. It is also shown that the methylene blue sensitized Co-doped nanostructures are highly stable under UV radiation and present a strong and broad absorption in the visible region.Comment: 31 pages, 3 tables, 7 figure

    Free monadic Tarski and MMI3-algebras

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    MMI3-algebras are a generalization of the monadic Tarski algebras as defined by A. Monteiro and L. Iturrioz, and a particular case of the MMIn+1-algebras defined by A. Figallo. They can also be seen as monadic three-valued £ukasiewicz algebras without a first element. By using this point of view, and the free monadic extensions, we construct the free MMI3-algebras on a finite number of generators, and indicate the coordinates of the generators. As a byproduct, we also obtain a construction of the free monadic Tarski algebras.Fil: Entizne, Rosana V.. Universidad Nacional del Sur. Departamento de Matemática; ArgentinaFil: Monteiro, Luiz F.. Universidad Nacional del Sur. Departamento de Matemática; ArgentinaFil: Savini, Sonia M.. Universidad Nacional del Sur. Departamento de Matemática; ArgentinaFil: Viglizzo, Ignacio Dario. Universidad Nacional del Sur. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentin

    Como Organizar um Rastreio Universal da Audição Neonatal

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    Com o aparecimento de técnicas de rastreio da audição sensíveis, especificas e de fácil execução, é possível implementar rastreios de audição que abranjam todos os recém-nascidos. O objectivo destes programas e a detecção precoce de todas as crianças com hipoacusia significativa até aos três meses de idade, com vista a iniciar a reabilitação antes dos seis meses. Neste artigo de revisão apontam-se os passos mais importantes da organização e implementação de um Rastreio Universal da Audição Neonatal (RUAN), em três fases, descrevendo-se as opções possíveis de técnicas, equipamento e pessoal a utilizar

    Rastreio Universal da Audição Neonatal um Pequeno Teste para o Audiologista , um Grande Passo para a Humanidade?

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    O Rastreio Universal da Audição Neonatal tem sido um objectivo que várias gerações de audiologistas, otorrinolaringologistas e pediatras tem tentado ao longo dos anos. Os autores fazem uma revisão dos principais métodos utilizados para a avaliação da audição dos recém-nascidos, bem como das dificuldades encontradas e limitações da sua utilização. Desde o inicio da década de noventa vêm a ser implementados verdadeiros métodos de detecção precoce e universal da surdez infantil, utilizando métodos fisiológicos tais como os potenciais evocados auditivos e as otoemissões acústicas (c1ássicos e automáticos). São descritos os artigos mais importantes que fundamentam a necessidade de diagnóstico e intervenção precoces na surdez sensorioneural, com vista a melhorar a aquisição e desenvolvimento da fala e da competência linguística, o que permite uma melhor integração da criança, independentemente do seu grau de surdez. São também enunciadas as directivas do "European Consensus Development on Neonatal Hearing Screening" e do "Joint Comitee on Infant Hearing"

    The electric vehicle in smart homes: a review and future perspectives

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    The electric mobility dissemination is forcing the adoption of new technologies and operation paradigms, not only focusing on smart grids, but also on smart homes. In fact, the emerging technologies for smart homes are also altering the conventional grids toward smart grids. By combining the key pillars of electric mobility and smart homes, this paper characterizes the paradigms of the electric vehicle (EV) in smart homes, presenting a review about the state of the art and establishing a relation with future perspectives. Since the smart home must be prepared to deal with the necessities of the EV, the analysis of both on board and off board battery charging systems are considered in the paper. Moreover, the in-clusion of renewable energy sources, energy storage systems, and dc electrical appliances in smart homes towards sustainability is also considered in this paper, but framed in the perspective of an EV off board battery charging system. As a pertinent contribution, this paper offers future perspectives for the EV in smart homes, including the possibility of ac, dc, and hybrid smart homes. Covering all of these aspects, exemplificative and key results are presented based on numerical simulations and experimental results obtained with a proof of concept prototype.FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by the FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017, and by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by FC

    Some boundary effects in quantum field theory

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    We have constructed a quantum field theory in a finite box, with periodic boundary conditions, using the hypothesis that particles living in a finite box are created and/or annihilated by the creation and/or annihilation operators, respectively, of a quantum harmonic oscillator on a circle. An expression for the effective coupling constant is obtained showing explicitly its dependence on the dimension of the box.Comment: 12 pages, Late

    Ages of White Dwarf-Red Subdwarf Systems

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    We provide the first age estimates for two recently discovered white dwarf-red subdwarf systems, LHS 193AB and LHS 300AB. These unusual systems provide a new opportunity for linking the reliable age estimates for the white dwarfs to the (measurable) metallicities of the red subdwarfs. We have obtained precise photometry in the VJRKCIKCJHV_{J}R_{KC}I_{KC}JH bands and spectroscopy covering from 6000\AA to 9000\AA for the two new systems, as well as for a comparison white dwarf-main sequence red dwarf system, GJ 283 AB. Using model grids available in the literature, we estimate the cooling age as well as temperature, surface gravity, mass, progenitor mass and {\it total} lifetimes of the white dwarfs. The results indicate that the two new systems are probably ancient thick disk objects with ages of at least 6-9 Gyr. We also conduct searches of red dwarf and white dwarf compendia from SDSS data and the L{\'e}pine Shara Proper Motion (LSPM) catalog for additional common proper motion white dwarf-red subdwarf systems. Only seven new candidate systems are found, which indicates the rarity of these systems.Comment: accepted for publication in Ap

    Ileocolic intussusception-a rare cause of acute intestinal obstruction in adults

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    The primary report of intussusception was made in 1674 by Barbette of Amsterdam. It increases the patient's risk of intestinal obstruction, parietal ischemia, perforation, and peritonitis. Small intestinal submucosal lipomas are an uncommon kind of gastrointestinal tumour. It is a silent disease that occasionally causes gastrointestinal haemorrhage, intussusception, and bowel obstruction. Surgery is frequently required to confirm the diagnosis and rule out an underlying malignancy. We present a case of submucosal lipoma causing enteric obstruction in a young female
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