3,605 research outputs found

    Pre-heating boiler feedwater for expanded cork agglomerate production using a parabolic trough system

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    ABSTRACT: The production of expanded cork agglomerate involves significant heat demand, requiring superheated steam at temperatures ranging from 300°C to 370°C. The energy required to this process can be suitably provided by concentrating solar thermal collectors. This work considers the thermal energy needs of a real plant, presenting the technical and economical analysis performed for a solar heat for industrial process system using parabolic trough collectors to preheat the feedwater used by the boiler providing steam to the expanded cork agglomerate production process.info:eu-repo/semantics/publishedVersio

    A low-cost ZigBee-based wireless industrial automation system

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    This paper describes the development of an industrial automation system based on a ZigBee wireless sensor network, designed for the monitoring and control of multiple refrigeration equipments in an industrial area, replacing the existing cabled network, which is based on the LonWorks platform. For this purpose, ZigBee routers were used to replace the local controllers at the refrigeration equipments, while the central management controller was re-placed by a ZigBee coordinator and a PC. The proposed system was devel-oped using a hardware platform based in the CC2530 integrated circuit and the Z-Stack software. Results from experimental field tests performed in an industrial environment are provided in order to assess the performance of the developed ZigBee network.This work is supported by FCT (Fundação para a Ciência e Tecnologia) with the reference project UID/EEA/04436/2013, and by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941

    Generalized inverses of a sum in rings

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    Documento submetido para revisão pelos pares. A publicar em "Bulletin of the Australian Mathematical Society". ISSN 0004-9727. 82:1 (2010) 156-164.We study properties of the Drazin index of regular elements in a ring with a unity 1. We give expressions for generalized inverses of 1 − ba in terms of generalized inverses of 1 − ab. In our development we prove that the Drazin index of 1 − ba is equal to the Drazin index of 1 − ab.Fundação para a Ciência e a Tecnologia (FCT) através do programa POCTIMinisterio de Educación y Ciencia of Spain - Project MTM2007-6723

    VIABILIDADE ECONÔMICA DE REDES DE DISTRIBUIÇÃO PROTEGIDAS

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    O objetivo deste estudo é demonstrar que a utilização generalizada das Redes Protegidas é viável em todas situações encontradas nos meios urbanos

    Immobilization of a Commercial Lipase from Penicillium camembertii (Lipase G) by Different Strategies

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    The objective of this work was to select the most suitable procedure to immobilize lipase from Penicillium camembertii (Lipase G). Different techniques and supports were evaluated, including physical adsorption on hydrophobic supports octyl-agarose, poly(hydroxybutyrate) and Amberlite resin XAD-4; ionic adsorption on the anionic exchange resin MANAE-agarose and covalent attachment on glyoxyl-agarose, MANAE-agarose cross-linked with glutaraldehyde, MANAE-agarose-glutaraldehyde, and epoxy-silica-polyvinyl alcohol composite. Among the tested protocols, the highest hydrolytic activity (128.2 ± 8.10 IU·g−1 of support) was achieved when the lipase was immobilized on epoxy-SiO2-PVA using hexane as coupling medium. Lipase immobilized by ionic adsorption on MANAE-agarose also gave satisfactory result, attaining 55.6 ± 2.60 IU·g−1 of support. In this procedure, the maximum loading of immobilized enzyme was 9.3 mg·g−1 of gel, and the highest activity (68.8 ± 2.70 IU·g−1 of support) was obtained when 20 mg of protein·g−1 was offered. Immobilization carried out in aqueous medium by physical adsorption on hydrophobic supports and covalent attachment on MANAE-agarose-glutaraldehyde and glyoxyl-agarose was shown to be unfeasible for Lipase G. Thermal stability tests revealed that the immobilized derivative on epoxy-SiO2-PVA composite using hexane as coupling medium had a slight higher thermal stability than the free lipase

    ASPECTOS QUE INFLUENCIAM A TOMADA DE DECISÃO DA MULHER SOBRE O TIPO DE PARTO

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    Objetivo: conhecer os aspectos que influenciam na tomada de decisão sobre o tipo de parto, por gestantes no terceiro trimestre de gestação. Método: estudo descritivo, qualitativo, realizado em 2015, com 15 grávidas. Realizaram-se entrevistas semiestruturadas e os dados foram posteriormente submetidos à análise de conteúdo. Resultados: o parto vaginal foi apontado como a via de preferência entre as gestantes. As experiências vivenciadas por familiares, por pessoas próximas e pela própria gestante, bem como sentimentos e sensações experimentadas, e a assistência pré-natal recebida foram os aspectos influenciadores na decisão da mulher. Conclusão: compreendeu-se que a escolha do tipo de parto não foi influenciada por um aspecto apenas, mas por uma série de fatores indissociáveis que, quando analisados separadamente, talvez não fossem capazes de influenciar a decisão.Descritores: Gestantes. Parto. Tomada de decisã

    Evaluation of APD and SiPM Matrices as Sensors for Monolithic PET Detector Block

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    Gamma detectors based on monolithic scintillator blocks coupled to APDs matrices have proved to be a good alternative to pixelated ones for PET scanners. They provide comparable spatial resolution, improve the sensitivity and make easier the mechanical design of the system. In this study we evaluate by means of Geant4-based simulations the possibility of replacing the APDs by SiPMs. Several commercial matrices of light sensors coupled to LYSO:Ce monolithic blocks have been simulated and compared. Regarding the spatial resolution and linearity of the detector, SiPMs with high photo detection efficiency could become an advantageous replacement for the APD
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