837 resultados para capacitors battery


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Os propósitos deste estudo foram os seguintes: (1) caracterizar a altura, o peso, a altura sentado e o índice de massa corporal (IMC); (2) construir tabelas e cartas centílicas das variáveis anteriormente referidas; (3) estimar as prevalências de sobrepeso e de obesidade; (4) apresentar dados descritivos da performance motora em ambos os sexos; (5) testar a hipótese da diferença de desempenho motor entre meninos e meninas e em função da idade; (6) identificar os testes, numa análise multivariada, que mais distinguem a performance de raparigas e rapazes; (7) estudar o efeito da adiposidade e actividade física numa medida compósita do desempenho motor; (8) comparar os valores médios das meninas e meninos da RAM com os das crianças dos Estados Unidos da América (EUA) e (9) apresentar cartas centílicas para idade e sexo. A amostra estratificada proporcional proveniente de 37 instituições escolares envolveu 836 alunos (417 raparigas e 419 rapazes) dos 3 aos 10 anos de idade que são parte integrante do projecto “Crescer com Saúde na RAM” (CRES). As medidas somáticas consideradas foram avaliadas de acordo com o protocolo do estudo de Crescimento de Lovaina (Bélgica) que segue as directrizes do Programa Biológico Internacional. O desempenho motor foi avaliado com a bateria de testes “Preschool Test Battery” (PTB). As diferentes análises estatísticas foram realizadas no SPSS 15 e Excel, sendo que α=5%.Verificaram-se incrementos significativos nas médias da estatura, peso, altura sentado e IMC, sem que haja diferenças sexuais acentuadas. A prevalência de sobrepeso foi, respectivamente, de 16.1% e 14.6% nas raparigas e rapazes; na obesidade os valores foram 7.7% e 8.8%. Relativamente ao desempenho motor, em ambos os sexos e ao longo da idade, é claro um aumento significativo nos valores médios da performance, sendo evidente a presença de dimorfismo sexual favorecendo os rapazes. Níveis mais elevados de adiposidade reflectem-se negativamente no desempenho motor, sendo que tal tendência não é tão evidente com os níveis de actividade física. As principais conclusões são as seguintes: (1) o crescimento é o esperado em condições socio-económicas favoráveis que a RAM vive; (2) há uma forte variabilidade inter-individual que reclama uma atenção cuidada por parte dos educadores; (3) não se verificam diferenças substanciais entre sexos que exijam uma atenção particular; (4) as prevalências de sobrepeso e obesidade impelem a um serviço de maior vigilância epidemiológica, maiores cuidados nos hábitos nutricionais, bem como a incrementos bem relevantes nos hábitos de actividade física e desportiva das crianças. Para finalizar, o desempenho permite as seguintes ilações: (5) é claro o incremento da performance em função da idade favorecendo os meninos; (6) a adiposidade tem um efeito negativo na performance que reclama uma atenção mais adequada dos educadores e progenitores; (7) o facto de não haver um efeito significativo da actividade física no desempenho motor pode dever-se a problemas com o instrumento utilizado; neste sentido sugerem-se outras abordagens, não esquecendo nunca os efeitos inequívocos e salutares dos níveis moderados e elevados no bem-estar e performance; (8) o facto das crianças da RAM terem desempenhos inferiores às dos EUA exige uma atenção adequada dos professores de Educação Física.

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It seeks to find an alternative to the current tantalum electrolytic capacitors in the market due to its high cost. Niobium is a potential substitute, since both belong to the same group of the periodic table and because of this have many similar physical and chemical properties. Niobium has several technologically important applications, and Brazil has the largest reserves, around 96%. There are including niobium in reserves of tantalite and columbite in Rio Grande do Norte. These electrolytic capacitors have high capacitance specifies, ie they can store high energy in small volumes compared to other types of capacitors. This is the main attraction of this type of capacitor because is growing demand in the production of capacitors with capacitance specifies increasingly high, this because of the miniaturization of various devices such as GPS devices, televisions, computers, phones and many others. The production route of the capacitor was made by powder metallurgy. The initial niobium powder supplied by EEL-USP was first characterized by XRD, SEM, XRF and laser particle size, to then be sieved into three particle size, 200, 400 e 635mesh. The powders were then compacted and sintered at 1350, 1450 and 1550°C using two sintering time 30 and 60min. Sintering is one of the most important parts of the process as it affects properties as porosity and surface cleaning of the samples, which greatly affected the quality of the capacitor. The sintered samples then underwent a process of anodic oxidation, which created a thin film of niobium pentóxido over the whole porous surface of the sample, this film is the dielectric capacitor. The oxidation process variables influence the performance of the film and therefore the capacitor. The samples were characterized by electrical measurements of capacitance, loss factor, ESR, relative density, porosity and surface area. After the characterizations was made an annealing in air ate 260ºC for 60min. After this treatment were made again the electrical measurements. The particle size of powders and sintering affected the porosity and in turn the specific area of the samples. The larger de area of the capacitor, greater is the capacitance. The powder showed the highest capacitance was with the smallest particle size. Higher temperatures and times of sintering caused samples with smaller surface area, but on the other hand the cleaning surface impurities was higher for this cases. So a balance must be made between the gain that is achieved with the cleaning of impurities and the loss with the decreased in specific area. The best results were obtained for the temperature of 1450ºC/60min. The influence of annealing on the loss factor and ESR did not follow a well-defined pattern, because their values increased in some cases and decreased in others. The most interesting results due to heat treatment were with respect to capacitance, which showed an increase for all samples after treatment

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The dielectric porcelain is usually obtained by mixing various raw materials proportions and is used in the production of electronic equipment for various applications, from capacitors of high and low Power to insulators for low, medium, high and extra high voltage, which are used in distribution lines and transmission of electricity.This work was directed to the s tudy of technological properties of technic porcelain, made from raw materials extracted from pegmatites found in the regions of Seridó and the Alto Oeste of Rio Grande do Norte, which are made of kaolin, quartz and feldspar, abundant and high quality in these regions. The technic ceramics were obtained by mixing in appropriate levels, kaolin, feldspar, quartz and clay, the last item from a pottery in the city of Sao Gonçalo do Amarante, Rio Grande do Norte. During the development the following characterizations correlated to raw materials were made: laser particle sizing, x-ray diffraction, DTA and TG. The compositions studied were formed by uniaxial pressing at a pressure of 50 MPa and sintered at temperatures ranging from 1150 to 1350ºC and levels (times) of sintering between 30, 60, 90 and 120 minutes. The characterization of the samples were taken from the analysis of weight loss, linear shrinkage, porosity, stoneware curve, bulk density, flexural strength of three points, SEM and X-ray diffraction, TMA, Dielectric and cross Resistivity. The studied materials can be employed in producing the objects used in electrical engineering such as: insulators for low, medium and high-voltage electrical systems, command devices, bushing insulation for transformers, power capacitors, spark plugs, receptacles for fluorescent and incandescent light bulbs and others

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Metallic tantalum has a high commercial value due to intrinsic properties like excellent ductility, corrosion resistance, high melt and boiling points and good electrical and thermal conductivities. Nowadays, it is mostly used in the manufacture of capacitors, due to excellent dielectric properties of its oxides. In the nature, tantalum occurs in the form of oxide and it is extracted mainly from tantalite-columbite ores. The tantalum is usually produced by the reduction of its oxide, using reductants like carbon, silicon, calcium, magnesium and aluminum. Among these techniques, the aluminothermic reduction has been used as the industrial method to produce niobium, tantalum and their alloys, due to the easy removal of the Al and Al2O3 of the system, easing further refining. In conventional aluminothermic reduction an electrical resistance is used to trigger the reaction. This reaction self-propagates for all the volume of material. In this work, we have developed a novel technique of aluminothermic reduction that uses the hydrogen plasma to trigger the reaction. The results obtained by XRD, SEM and EDS show that is possible to obtain a compound rich in tantalum through this technique of aluminothermic reduction in the plasma reactor

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The identification of the factors that interfere in the decline of functional conditions is useful in the planning of actions addressing the improvement in the conditions of the lives of elderly people. The purpose of this investigation was to analyze the relationship between social demographics and health aspects of the functional condition in elderly women of low income of the Brazilian northeast. This crosssectional study involved a representative sample of 222 women with an average age of 70 years (± 7.1), belonging to coexisting groups and that were resident in the urban area of the municipal district of Jequié /Bahia. In order to achieve this objective, a battery of physical tests of functional aptitude was carried out previously tested in pilot study, anthropometric measurements collected with a comparison of the measures referred to the reported weight and height as well as the application of an interview with questions containing subjects related to social demographic variables, clinical conditions and health, physical conditions and behaviors. Descriptive statistics Proceedings (frequency, average, standard deviation and percent distribution) were used for statistic analysis, and the calculation of the respective odds ratio by binary logistics regression, for the analysis of factors hierarchically grouped; p<0.05. The prevalence of 56% (n=122) of women considered with moderated or serious type of functional limitations was found, In which from multi-varied hierarchical analysis, significant association was verified with the age group over 80 years (p=0.02), conditions of widowhood (p=0.04), presence of arterial hypertension (p=0.001), and physical inactivity during leisure time (p=0.03). On the other hand for functional incapacities the prevalence was of 46.8% (n=104) being associated to the increase of the age (p=0.01), hospitalization (p=0.02), absence of physical activities along their lives (p=0.001) and the occurrence of alterations in the cognitive function (p=0.001). The normative table for the parameters of physical fitness generated conducive to health professionals in the diagnosis of health conditions and the prescription of physical exercises. The identified characteristics that are associated with the functional limitations / functional incapacities suggest a complex causal net in the determination of the functional condition in elderly women. However, actions addressed to the incentive of the practice of physical activities in the leisure time and the preservation of the cognitive function can contribute to a life with more quality for these people. This research was multidisciplinary approach to involve elements of psychology, nutrition and Physical Education in the elucidation of the object of study related to the functional condition of elderly women

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Osgood-Schlatter (O-S) syndrome, a pathology of the musculoskeletal system, exhibits high incidence in adolescence, a phase of accelerated bone growth. Detection of physiopathological mechanisms that may cause disorders and dysfunctions in bone growth must be taken into account when planning physical activities, in order to promote normal physiological growth patterns. The aim of this epidemiological investigation was to identify and analyze the relationships between sociodemographic, anthropometric and clinical aspects and O-S. A cross-sectional design was used, with a representative sample of 956 subjects: 474 (49.6%) males and 482 (50.4%) females. Age range varied between 12 and 15 years (mean = 13.7±1.04). We used a battery of tests, previously applied in a pilot study, which met the aims of the investigation. Descriptive statistics (frequency, mean and standard deviation) were used and the odds ratio was calculated from bivariate and multivariate logistic regression (p<0.05). A prevalence of 9.8% was found (n = 94 cases): 11% males and 8.3% females. Hierarchized multivariate analysis showed a significant association between regular physical activities (OR= 1.94; CI 95%, 1.22-3.10) and shortening of the rectus femoris muscle (OR= 7.15; CI 95%, 2.86-17.86). The results may serve as a basis for therapeutic and prophylactic measures, in addition to increasing our knowledge of this syndrome in Brazilian adolescents. This investigation used a multidisciplinary approach, involving elements of anatomy, nutrition, physical education and physical therapy to elucidate the object under study related to Osgood-Schlatter syndrome

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico

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O processo de envelhecimento da humanidade é um fenômeno mundial e nas últimas décadas a população brasileira tem acompanhado essa tendência. No entanto, este fenômeno somente pode ser considerado como uma real conquista em termos sócios demográficos na medida em que se agregue qualidade aos anos adicionais de vida para a população. Em populações idosas, a incapacidade funcional e os sintomas depressivos tornaram-se importantes conceitos tanto por suas consequências para a saúde pública, quanto pelo impacto na qualidade de vida dessas populações. Este estudo tem como objetivo verificar se há associação entre os sintomas depressivos e o desempenho funcional de idosos comunitários. Foram avaliados 313 idosos de um centro urbano do nordeste brasileiro através das baterias de testes; Center for Epidemiologic Studies Depression CES-D e Short Physical Performance Battery - SPPB; além de variáveis relacionadas ao estado físico, condições crônicas, função cognitiva e características sócio demográficas. Foram utilizadas medidas de correlação e aplicado método de análise multivariada para construir um modelo explicativo da influência da sintomatologia depressiva no desempenho funcional. Os resultados revelaram que as mulheres apresentaram mais sintomas depressivos (p< 0.01) e pior desempenho funcional (p< 0.01) que os homens. Os indivíduos com sintomatologia depressiva apresentaram pior desempenho funcional, especialmente as mulheres. A idade, o sexo feminino, o estado de saúde percebido, o nível de função cognitiva e o Índice de massa corporal foram identificados como fatores associados ao desempenho funcional na amostra estudada. Os resultados deste estudo permitem inferir a relação de associação entre sintomas depressivos e desempenho funcional em uma população de idosos de um centro urbano no nordeste do Brasil. Estes resultados fornecem informações úteis para intervenções terapêuticas adequadas voltadas para a prevenção do declínio na mobilidade em idosos

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We describe the isolation and characterization of ten microsatellite loci from the red-winged tinamou (Rhynchotus rufescens) and also evaluated the cross-amplification of these loci and other ten loci previously developed for the great tinamou (Tinamus major) in other tinamous. Genetic variability was assessed using 24 individuals. Six loci were polymorphic with moderate to high number of alleles per locus (2-12 alleles) and showed expected heterozygosity (HE) ranging from 0.267 to 0.860. All loci conformed to the Hardy-Weinberg expectation and linkage disequilibrium was not significant for any pair of loci. This battery of polymorphic loci showed high paternity exclusion probability (0.986) and low genetic identity probability (4.95 x 10(-5)), proving to be helpful for parentage tests and population analyses in the red-winged tinamou. The cross-amplification was moderate where of the 160 locus/taxon combinations, 46 (28.75%) successfully amplified.

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This dissertation describes the implementation of a WirelessHART networks simulation module for the Network Simulator 3, aiming for the acceptance of both on the present context of networks research and industry. For validating the module were imeplemented tests for attenuation, packet error rate, information transfer success rate and battery duration per station

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Low voltage solar panels increase the reliability of solar panels due to reduction of in series associations the configurations of photovoltaic cells. The low voltage generation requires DCDC converters devices with high efficiency, enabling raise and regulate the output voltage. This study analyzes the performance of a photovoltaic panel of Solarex, MSX model 77, configured to generate an open circuit voltage of 10.5 V, with load voltage of 8.5 V, with short circuit current of 9 A and a power of 77 W. The solar panel was assembled in the isolated photovoltaic system configuration, with and without energy storage as an interface with a DCDC converter, Booster topology. The converter was designed and fabricated using SMD (Surface Mounted Devices) technology IC (integrated circuit) that regulates its output voltage at 14.2 V, with an efficiency of 87% and providing the load a maximum power of 20.88 W. The system was installed and instrumented for measurement and acquisition of the following data: luminosities, average global radiation (data of INPE Instituto Nacional de Pesquisas Espaciais), solar panel and environment temperatures, solar panel and DC-DC converter output voltages, panel, inverter, and battery charge output currents. The photovoltaic system was initially tested in the laboratory (simulating its functioning in ideal conditions of operation) and then subjected to testing in real field conditions. The panel inclination angle was set at 5.5°, consistent with the latitude of Natal city. Factors such as climatic conditions (simultaneous variations of temperature, solar luminosities and ra diation on the panel), values of load resistance, lower limit of the maximum power required by the load (20.88 W) were predominant factors that panel does not operate with energy efficiency levels greater than 5 to 6%. The average converter efficiency designed in the field test reached 95%

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Numerical cognition is based on two components - number processing and calculation. Its development is influenced by biological, cognitive, educational, and cultural factors. The objectives of the present study were to: i) assess number processing and calculation in Brazilian children aged 7-12 years from public schools using the Zareki-R (Battery of neuropsychological tests for number processing and calculation in children, Revised; von Aster & Dellatolas, 2006) in order to obtain normative data for Portuguese speakers; ii) identify how environment, age, and gender influences the development of these mathematical skills; iii) investigate the construct validity of the Zareki-R by the contrast with the Arithmetic subtest of WISC-III. The sample included 172 children, both genders, divided in two groups: urban (N= 119) and rural (N= 53) assessed by the Zareki-R. Rural children presented lower scores in one aspect of number processing; children aged 7-8 years demonstrated an inferior global score than older; boys presented a superior performance in both number processing and calculation. Construct validity of Zareki-R was demonstrated by high to moderate correlations with Arithmetic subtest of WISC-III. The Zareki-R therefore is a suitable instrument to assess the development of mathematical skills, which is influenced by factors such as environment, age, and gender.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)