249 research outputs found

    Strain and dynamic measurements using fiber optic sensors embedded into graphite/epoxy tubes

    Get PDF
    Graphite/epoxy tubes were fabricated with embedded optical fibers to evaluate the feasibility of monitoring strains with a fiber optic technique. Resistance strain gauges were attached to the tubes to measure strain at four locations along the tube for comparison with the fiber optic sensors. Both static and dynamic strain measurements were made with excellent agreement between the embedded fiber optic strain sensor and the strain gauges. Strain measurements of 10(exp -7) can be detected with the optical phase locked loop (OPLL) system using optical fiber. Because of their light weight, compatibility with composites, immunity to electromagnetic interference, and based on the static and dynamic results obtained, fiber optic sensors embedded in composites may be useful as the sensing component of smart structures

    DESIGN, FABRICATION AND EXPERIMENTAL STUDY OF A FLAT PLATE COLLECTOR SIMULATOR

    Get PDF
    In this article, a flat plate collector simulator was designed and developed based on the use of electric heaters and a power control system. A computational algorithm aimed at determining the relationship between the incident solar energy on the collector absorber plate and the corresponding amount of power that must be supplied by the electrical resistance was developed. The variation in power is obtained by regulating the voltage fed through the assembly. With such regulation, simulating typical profiles of insolation over a day was possible. In the assessment of the average solar radiation data obtained by satellite imagery analysis (SWERA Project), the results showed that the thermal behavior of the simulator collector was close with a real behavior. Therefore, it can be used to determine the operating characteristics of auxiliary power systems as heat pumps, electrical systems or water heating systems. Different thermodynamic processes to determine the main losses of a collector evaluated the simulation parameters

    SOCIO-ECONOMIC PERFORMANCE OF A SOLAR FLAT PLATE COLLECTOR BASED IN A HEAT PUMP WATER HEATING SYSTEM IN THE BRAZILIAN SOUTHEAST

    Get PDF
    By increasing renewable energy demand, the use of solar energy has been widely investigated over the recent years. Brazil is a privileged country in terms of the levels of receivable solar radiation in almost all over its territory. However, as there are days when there is a deficit in solar energy, because the day be cloudy or rainy days, and for this reason, solar collectors need a support to contribute to the water heating to the desired temperature. In this work, an experimental study of a heat pump operated with R-134a, as an ancillary equipment for a solar water heating system in Belo Horizonte city has been accomplished. For this project, is used a set of electrical resistances for by a power control step, simulate historical annual values of solar radiation. In the results, it was observed that is achieved through the collection of solar energy the temperature of 45°C in the reservoir only in January, and the other eleven months is necessary to use the heat pump to achieve reach that temperature. With the heat pump operating in conditions similar to real conditions gave an average annual consumption of 137.65 kWh and a cost of R$ 60.61

    SOCIO-ECONOMIC PERFORMANCE OF A SOLAR FLAT PLATE COLLECTOR BASED IN A HEAT PUMP WATER HEATING SYSTEM IN THE BRAZILIAN SOUTHEAST

    Get PDF
    By increasing renewable energy demand, the use of solar energy has been widely investigated over the recent years. Brazil is a privileged country in terms of the levels of receivable solar radiation in almost all over its territory. However, as there are days when there is a deficit in solar energy, because the day be cloudy or rainy days, and for this reason, solar collectors need a support to contribute to the water heating to the desired temperature. In this work, an experimental study of a heat pump operated with R-134a, as an ancillary equipment for a solar water heating system in Belo Horizonte city has been accomplished. For this project, is used a set of electrical resistances for by a power control step, simulate historical annual values of solar radiation. In the results, it was observed that is achieved through the collection of solar energy the temperature of 45°C in the reservoir only in January, and the other eleven months is necessary to use the heat pump to achieve reach that temperature. With the heat pump operating in conditions similar to real conditions gave an average annual consumption of 137.65 kWh and a cost of R$ 60.61

    Operação Bororos: vivências de saúde, educação e cultura na Chapada dos Guimarães

    Get PDF
    Trabalho apresentado no II Congresso Nacional do PROJETO RONDON, realizado em Florianópolis, SC, no período de 23 a 25 de setembro de 2015 - Universidade Federal de Santa Catarina.Introdução: O Projeto Rondon é um programa interministerial, coordenado pelo Ministério da Defesa, que visa integrar e desenvolver ações comunitárias em regiões com maiores índices de pobreza e exclusão social, bem como áreas isoladas do território nacional necessitadas de maior aporte de bens e serviços. Em parceira com as universidades, o projeto pretende contribuir com a formação do universitário como cidadão, integrá-lo ao processo de desenvolvimento nacional por meio de ações participativas sobre a realidade do país. Além disso, visa consolidar no universitário o sentido de responsabilidade social coletiva, em prol da cidadania estimulando a produção de projetos coletivos locais, em parceria com as comunidades, com foco na capacitação de agentes multiplicadores, estimulando ações que valorizem o cidadão, a cultura local e promovam o intercâmbio de informações. Com esse espírito, a Instituição de Ensino Superior (IES) desenvolveu um plano de trabalho, aprovado para execução no município de Chapada dos Guimarães, estado do Mato Grosso, durante a Operação Bororos, no período de 10 a 26 de julho de 2015. Objetivo: Descrever as atividades realizadas no município, direcionadas aos profissionais de saúde, educação, assistência social e à comunidade em geral. Metodologia: A descrição se dará a partir do registro documental e fotográfico das atividades desenvolvidas e das avaliações feitas pelos participantes. Resultados: Foram realizadas 22 atividades de cultura, comunicação, saúde e educação, por meio de oficinas teórico-práticas, simpósios, mutirão de saúde e rodas de conversa, com participação de 293 pessoas. A maior parte das atividades foi concentrada na área urbana do município, em escolas, creches, centros culturais, praças e feiras ao ar livre. Observaram-se benefícios à comunidade com a troca de saberes e informações ofertadas pelos universitários, uma vez que agregaram novos subsídios para o trabalho cotidiano, seja dos multiplicadores ou dos cidadãos em geral que tiveram acesso às atividades desenvolvidas. Conclusão: O Projeto Rondon consolida-se como oportunidade única para os universitários colocarem em prática os conhecimentos adquiridos ao longo de suas vivências acadêmicas em prol da sociedade. Observou-se a necessidade de adequação das atividades priorizando-se as populações rurais caracterizadas como mais vulneráveis

    Reference Percentiles for Bioelectrical Phase Angle in Athletes

    Get PDF
    The present study aimed to develop reference values for bioelectrical phase angle in male and female athletes from different sports. Overall, 2224 subjects participated in this study [1658 males (age 26.2±8.9 y) and 566 females (age 26.9±6.6 y)]. Participants were categorized by their sport discipline and sorted into three different sport modalities: Endurance, velocity/power, and team sports. Phase angle was directly measured using a foot-to-hand bioimpedance technology at a 50 kHz frequency during the in-season period. Reference percentiles (5th, 15th, 50th, 85th, and 95th) were calculated and stratified by sex, sport discipline and modality using an empirical Bayesian analysis. This method allows for the sharing of information between different groups, creating reference percentiles, even for sports disciplines with few observations. Phase angle differed (men: P<0.001; women: P=0.003) among the three sport modalities, where endurance athletes showed a lower value than the other groups (men: Vs. velocity/power: P=0.010, 95% CI=−0.43 to −0.04; vs. team sports: P < 0.001, 95% CI=−0.48 to −0.02; women: Vs. velocity/power: P=0.002, 95% CI=−0.59 to −0.10; vs. team sports: P=0.015, 95% CI=−0.52 to−0.04). Male athletes showed a higher phase angle than female athletes within each sport modality (endurance: p<0.01, 95% CI=0.63 to 1.14; velocity/power: P<0.01, 95% CI=0.68 to 1.07; team sports: P<0.01, 95% CI=0.98 to 1.23). We derived phase angle reference percentiles for endurance, velocity/power, and team sports athletes. Additionally, we calculated sex-specific references for a total of 22 and 19 sport disciplines for male and female athletes, respectively. This study provides sex and sport-specific percentiles for phase angle that can track body composition and performance-related parameters in athletes

    Negative Autoregulation by Fas Stabilizes Adult Erythropoiesis and Accelerates Its Stress Response

    Get PDF
    Erythropoiesis maintains a stable hematocrit and tissue oxygenation in the basal state, while mounting a stress response that accelerates red cell production in anemia, blood loss or high altitude. Thus, tissue hypoxia increases secretion of the hormone erythropoietin (Epo), stimulating an increase in erythroid progenitors and erythropoietic rate. Several cell divisions must elapse, however, before Epo-responsive progenitors mature into red cells. This inherent delay is expected to reduce the stability of erythropoiesis and to slow its response to stress. Here we identify a mechanism that helps to offset these effects. We recently showed that splenic early erythroblasts, ‘EryA’, negatively regulate their own survival by co-expressing the death receptor Fas, and its ligand, FasL. Here we studied mice mutant for either Fas or FasL, bred onto an immune-deficient background, in order to avoid an autoimmune syndrome associated with Fas deficiency. Mutant mice had a higher hematocrit, lower serum Epo, and an increased number of splenic erythroid progenitors, suggesting that Fas negatively regulates erythropoiesis at the level of the whole animal. In addition, Fas-mediated autoregulation stabilizes the size of the splenic early erythroblast pool, since mutant mice had a significantly more variable EryA pool than matched control mice. Unexpectedly, in spite of the loss of a negative regulator, the expansion of EryA and ProE progenitors in response to high Epo in vivo, as well as the increase in erythropoietic rate in mice injected with Epo or placed in a hypoxic environment, lagged significantly in the mutant mice. This suggests that Fas-mediated autoregulation accelerates the erythropoietic response to stress. Therefore, Fas-mediated negative autoregulation within splenic erythropoietic tissue optimizes key dynamic features in the operation of the erythropoietic network as a whole, helping to maintain erythroid homeostasis in the basal state, while accelerating the stress response
    corecore