300 resultados para Eletrodos modificados
Resumo:
O presente trabalho procura descrever o histórico e a trajetória percorrida pela soja em sua expansão pelo território nacional, considerando a utilização da soja transgênica. Explica quais diferenças e melhorias a soja transgênica apresenta em comparação a soja convencional, discutindo-se a liberalização ou não do uso e consumo de produtos derivados de transgênicos. Expõem ainda, quais foram os fatores preponderantes para a escolha do uso dessa técnica: a rede de persuasão e controle criada e coordenada pela Monsanto e a redução do custo de produção, através da diminuição do uso de herbicidas
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The use of multimodal neuroimaging techniques has been helpful in the investigation of epileptogenic zone in patients with refractory epilepsies. This work aims to describe an ictal event during EEG-fMRI performed simultaneously in a 39-year-old man with refractory epilepsy. The EEG data were recorded at a sampling rate of 5 kHz, using a BrainAmp (BrainProducts, München, Germany) amplifier, with 64 MR (magnetic resonance) compatible Ag/AgCl electrodes. MR images were acquired using a 3T scanner in 3 sequences of 6 minutes of echo-planar images (EPIs), with TR = 2s, being the last sequence stopped after the ictal event. The EEG was corrected for gradient and pulse artifacts using the Brain Vision Analyzer2 software (BrainProducts), and the functional images were realigned, slice-timing corrected, normalized and smoothed. The start of the ictal changes was used for the evaluation of the BOLD response in MR images, using a t-test with a minimum cluster of 5 voxels, p <0.005 (T>2.5). The patient had a partial complex seizure, as noted by neurologist. The fMRI data showed positive BOLD responses (activation) in dysplastic areas, but showed the most significant activation outside the lesion, in areas compatible with secondary spread of the epileptic focus, probably caused by motor reaction also observed during the seizure. As a conclusion, we note that the technique of EEG-fMRI can detect the epileptogenic zone in patients with refractory epilepsy, but areas of dissemination of primary epileptogenic focus may show significant activation, introducing additional difficulties to the interpretation of the results
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During the twentieth century the inorganic electronics was largely developed being present in various industrial equipment or household use. However, at the end of that century were verified electronic properties in organic compounds, giving rise to the field of organic electronics. Since then, the physical properties of elementary devices such as diodes and organic transistors have been studied. In this work was studied the properties of diode devices fabricated with a semiconductor polymer, the poly-o-methoxyaniline (POMA). Devices containing electrodes of Au and Al were fabricated with semiconductor polymer of different doping levels. We found that the rectifying behavior for the heterojunctions metal/polimer are reached only for high doping level (with conductivity greater than 1,77. 10-9 S / cm), which gives the devices characteristic of a Schottky diode. The rectifying behavior was observed for electric fields of low magnitude, below the operating field (~ 600 V/cm), while for electric field greater than 600 V/cm the a linear behavior I vs.V was obtained. We determined that this Ohmic behavior arises from the charge transport over the volume of the semiconductor material after the lowering of the metal/semiconductor barrier. In devices with weakly doped semiconductor, the electrical resistance of the volume becomes high and the process of charge transportation is dominated by the volume, for any intensity of the applied electric field
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A busca por alimentos chamados popularmente de orgânicos, produzidos sem o uso de agrotóxicos, fertilizantes, insumos químicos ou organismos geneticamente modificados, vem se consolidando mundialmente. O crescimento do mercado mundial de produtos orgânicos criou uma demanda pela normatização, regulamentação e certificação da produção orgânica em diversos países. Por pressão de países importadores, houve a necessidade de que produtos orgânicos brasileiros fossem certificados através de normas e padrões de qualidade reconhecidos internacionalmente. Este trabalho tem como objetivo descrever a legislação brasileira referente à certificação de produtos orgânicos. Foram descritos os conteúdos das leis e normas que compõem o arcabouço legal referente ao tema. A regulamentação da agricultura orgânica no Brasil teve início com publicação da Lei 10.831/2003 e sua regulamentação pelo Decreto 6.323/2007, que estabeleceu a obrigatoriedade da certificação de produtos orgânicos por organismo de certificação reconhecido oficialmente. Todos aqueles que produzem, transportam, comercializam ou armazenam produtos orgânicos (exceto aqueles pertencentes à agricultura familiar) ficaram obrigados a regularizar suas atividades e estarem inseridos no Cadastro Nacional de Produtores Orgânicos
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Propomos nesta monografia o projeto de um escritório de arquitetura anexo a um canteiro escola, tendo como objetivo capacitar pessoas das comunidades periféricas em Presidente Prudente. Ao levar o arquiteto para dentro desta problemática das cidades, ajudaremos a sanar os problemas arquitetônicos de moradias sem qualidade nas comunidades carentes. O canteiro escola é um local onde a população irá aprender a teoria e prática da construção civil e, a partir deste momento, efetuar a autoconstrução de maneira correta eatingir a profissionalização. O Canteiro Escola acontecerá em contêineres de carga modificados, esta estrutura já possui adequação para transporte e, se necessário, poderá haver movimentação entre os bairros da cidade
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The easy access to information has been accelerating even more business competitiveness nowadays. To turn a foreign trade company into a more competitive company by improving its services, this work aims the analysis of the Supply Chain processes to enable greater productivity. Using powerful tools of great historical success in the business world – such as Flowcharts, VSM Lean and PDCA –, a structure was created that adapted its main concepts and produced a method which enabled not only improvements on modified processes but also on the subsequent ones. Productivity data were collected, where evidence of quantitative improvements were found in the expedition macro process. Due to a process analysis theme, this paper gives also the thought about process approach, vital step to create a future Quality Management System
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Fuel cells are a very promising solution to the problems of power generation and emission of pollutant to the environment, excellent to be used in stationary application and mobile application too. The high cost of production of these devices, mainly due to the use of noble metals as anode, is a major obstacle to massive production and deployment of this technology, however the use of intermetallic phases of platinum combined with other metals less noble has been evaluated as electrodes in order to minimize production costs and still being able to significantly improve the catalytic performance of the anode. The study of intermetallic phases, exclusively done by experimental techniques is not complete and demand that other methods need to be applied to a deeper understanding of the behavior geometric properties and the electronic structure of the material, to this end the use of computer simulation methods, which have proved appropriate for a broader understanding of the geometric and electronic properties of the materials involved, so far not so well understood.. The use of computational methods provides answers to explain the behavior of the materials and allows assessing whether the intermetallic may be a good electrode. In this research project was used the Quantum-ESPRESSO package, based on the DFT theory, which provides the self-consistent field calculations with great precision, calculations of the periodic systems interatomic force, and other post-processing calculations that points to a knowledge of the geometric and electronic properties of materials, which may be related to other properties of them, even the electrocatalytic. The electronic structure is determined from the optimized geometric structure of materials by analyzing the density of states (DOS) projected onto atomic orbital, which determines the influence of the electrocatalytic properties of the material... (Complete abstract click electronic access below)
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This paper presents the study on the application of the electrolytic plasma for surface treatment of aluminum. A bibliographical study on the material of interest was preliminarily performed and later designed and built an electrolytic cell, including the excitation source. Unlike conventional electrolysis process, the plasma assisted carry on in the non-linear region of characteristic current/voltage curve. Therefore it requires for the on set of the process that the power supply operates on harder conditions than those on high current process. The plasma produced during the present investigation has temperatures in the range o 6,0.10 3 -7,0 .10 3 K, well above those found in conventional chemical process. It also shows a particular dynamic to promote changes on surface and to produce new materials. The plasma is generated by microdischarge in vapor or gas bubbles involved in physic-chemical processes in electrode regions of the electrolytic cell. The electrode material was the aluminum (7075). The Process Electrolytic Plasma Processing (EPP) is sensitive to various parameters such as operating voltage, current density, electrolyte, concentration of electrolyte, geometry of reactor, temperature of electrolytic solution and dynamic of the fluid in the cell. The experiments were carried on in order to find parameters for a stable abd steady operation. The choice for the electrolytic was silicate/alkali solution in various concentrations to operate in various voltage as well. Plasma was produced on negative (cathode) and positive (anode) electrode, in specific conditions. A stable operation on the cathode process was obtained with low concentration of the electrolytic in aqueous solution, current density around 250V effective voltage. For the evolution of plasma in anodic process it was required higher concentrations and higher... (Complete abstract click electronic access below)
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A função normal dos músculos escapulotorácicos é um dos componentes vitais para a estabilidade dinâmica do complexo do ombro. A maioria dos estudos aborda o controle dinâmico da escápula, porém o comportamento muscular no controle estático da mesma tem sido menos frequente. O objetivo do estudo foi analisar a ação simultânea dos músculos serrátil anterior e as três porções do trapézio durante o movimento de rotação interna e externa do ombro, entre voluntários assintomáticos. 10 indivíduos com idade entre 20 e 40 anos foram avaliados com testes de movimentos de rotação do ombro direito e esquerdo, contra uma resistência elástica (40% da CIVM), para captação de EMG por meio de eletrodos de superfície nos músculos: trapézio ascendente (TA), trapézio transverso (TT), trapézio descendente (TD) e serrátil anterior (SA). Foram obtidos valores de Contração Isométrica Voluntária Máxima (CIVM) para os músculos rotadores do ombro e TA, TT, TD e SA. Os sinais foram normalizados pela CIVM e processados no software Matlab, gerando curvas médias de ativação simultânea para cada par muscular (TA/TT; TA/TD; TA/SA; TT/TD; TT/SA; e TD/SA). A quantidade de cocontração dos pares musculares foi baixa (variação média de 2,3% a 11% da CIVM), e os pares em combinação com o SA tiveram tendência de maiores valores; a variabilidade encontrada foi baixa e a confiabilidade foi adequada (ICC > 0,70). Os baixos valores de co-contração encontrados neste estudo eram esperados, concordando com a biomecânica do movimento utilizado e com os estudos que avaliaram os mesmos músculos em outras condições; o movimento de RE apresentou co-contração levemente maior que a RI e isto sugere que a RE é um movimento mais instável, além de ser considerado o movimento mais fraco do ombro. Diante dos resultados encontrados, conclui-se que a metodologia utilizada foi... (Resumo completo, clicar acesso eletrônico abaixo)
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O joelho, por suas características anatômicas e freqüente instabilidade e exposição as lesões tem o quadríceps como importante músculo a ser desenvolvido quanto ao seu trofismo e força. Composto de quatro porções distintas estas podem gerar diferentes vetores de força que podem ter relações diretas com o recrutamento de unidades motoras. O posicionamento articular, a conseqüente modificação do comprimento muscular e a intensidade da contração podem influenciar o desenvolvimento da força do quadríceps. Dentre as contrações relacionadas ao maior recrutamento de unidades motoras com o intuito do desenvolvimento de força está a contração isométrica. Dentre as contrações musculares, as isométricas têm sido frequentemente indicadas para aumentar a força e estabilidade articular em sessões de treinamento e reabilitação. Pelo exposto, o objetivo do estudo foi analisar os músculos vasto medial (VM) e vasto lateral (VL) por meio da eletromiografia de superfície durante 15s de contração isométrica a 20%, 30%, 40% e 50% da contração isométrica voluntária máxima – CIVM com o joelho a 90 graus. Foram utilizados eletrodos de superfície bipolar de Ag/AgCl, posicionados nos músculos VM e VL, um módulo de aquisição de sinais biológicos (Lynx) calibrado com ganho de 1000vezes, filtro de passa alta de 20Hz e de passa baixa de 500Hz. Uma célula de carga foi acoplada perpendicularmente à cadeira de teste especialmente desenvolvida para o estudo e utilizado uma indicador digital para retorno visual. Na análise estatística utilizou-se teste de Friedman e teste de Wilcoxon, e adotou-se nível de significância de p<0,05. Verificou-se que os músculos VM e VL foram semelhantes entre si, e entre as cargas, houve diferença significante entre as cargas de 20% e 40%, 20% e 50%, e 30% e 50% para ambos os músculos, com maior atividade nas cargas de 40% e 50% CVM... (Resumo completo, clicar acesso eletrônico abaixo)
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The objective of this study was to analyze the influence of previous exercise on the determination of critical power (CP). Seven apparently healthy nontrained males, of 18 to 25 years, participated of this study. The subjects were submitted, in different days to the following protocols in a cyclergometer: 1) one progressive test until voluntary exhaustion for the determination of lactate threshold (LL), maximal oxygen uptake (VO2max) and its corresponding intensity (IVO2max); 2) six constant workload tests at 95,100 and 110% IVO2max until exhaustion with and without a previous exercise at 70% , in random order. The exhaustion times (tlim) at 95, 100 and 110% IVO2max were adjusted forme thress models of two parameters to estimate CP and anaerobic work capacity (AWC) [P=CTAn/tlim)+CP; tlim = CTAn/(P-PC); P=PC.tlim+ CTAn]. The model with the lowest standard error was considered for the estimation of CP. The tlim at 95% IVO2max was similar without (501 ± 140 s) and with previous exercise (473 ± 99 s). However, the tlim at 100% (381 ± 103 s and 334 ± 101 s) and 110% IVO2max (267 ± 163 s and 227 ± 68 s) was significantly longer with previous exercise. There was no significant difference in CP and AWCat conditions without (200 ± 27 W and 23 ± 11 kJ, respectively) and with previous exercise (212 ± 30 W and 18 ± 8 kJ, respectively). It can be concluded that the parameters of the relationship between power and time were not modified by the previous severe exercise
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The study of mechanical properties of high-alloy special steels is of great interest of the steel industry due to the great demand by companies that manufacture automotive components of high criticality, and also because of its high commercial value. However, the development of this type of alloy metals demand highly technical knowledge. Among these extremely important kinds of steel, the subject which is the interest of this study is the special steel modified by niobium. The manganese and niobium are the main alloying elements in the composition of these steels, both of them increase the stability of the austenite region, however, manganese increases the hardenability and tensile yield strength, and niobium increases the mechanical strength and promotes refining the grain. The mechanical characterization of steel SAE 1312 modified the niobium was made in order to gain a better understanding of the influence on the mechanical properties caused by aging at different temperatures and for different reductions in the drawing of gauge material. This characterization was made by means of tensile test and hardness. This material showed an increase in yield strength and hardness when gauge with large reductions during the wiredrawing, but when subjected to aging temperatures higher than 300 ° C had a slight loss of these properties
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Individuals of the species Turdus leucomelas are adapted to live in environments already modified by humans, thus obtaining reproductive success in their nesting in vegetation, as well as built their nests in human buildings. Nests found in buildings are often less camouflaged, making them more exposed to predators compared to nests built in vegetation; however the nests built buildings are common, indicating a possible advantage associated with these nests. By means of this idea if was assumed that a possible advantage to this construction in buildings is linked to a change in variation in the internal temperature of the nest during incubation and development of pups until they leave their nests. Accordingly, with the aid of iButtons and TidBits (temperature data loggers), the present study aimed to analyze the influence of the nesting site on how the temperature is kept, and how it changes in the microenvironment in which the nest is inserted, indicating potential benefits associated with that choice. In the samples found with the vegetation, temperature data showed a pattern of temperature of the microenvironment of the nests is not very stable, varying with ambient temperature, whereas in the samples found with the human constructions, the temperature data showed a pattern of temperature microenvironment nests more stable for a long time. When comparing the two environments which they settled nests, as well as the different times of day (daytime and nighttime), how the temperature was kept and pattern of change within the nest was significantly different (F=43.85, p<0.001), with higher and more constant internal temperatures in nests installed in construction, compared to vegetation. When observing periods of the day, it was found that in both environments the temperature inside the nest reached higher values and higher than the environment at night, coinciding with the rest of the female at night. Data may suggest changes in the...
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A inatividade física é uma das principais causas de morte no mundo, e um dos principais fatores de risco para doenças não transmissíveis. Os fatores de risco destas doenças podem ser prevenidos com modificações no estilo de vida, que reduz eventos cardiovasculares e aumenta a sobrevida de pacientes portadores ou em risco de coronariopatias. Entendendo de como estes agentes casuais se predispõem ao surgimento de cardiopatias, o acompanhamento de fatores de risco ajudam na identificação de sinais antecessores à doença, que podem ser modificados, atenuados e até mesmo revertidos. O objetivo do presente estudo foi de verificar a influência de um ano de prática regular de Atividade Física nas variáveis bioquímicas (bioquímicas (glicose, triglicérides, HDL, LDL, e colesterol total), circunferência de quadril e abdominal e Indice de Massa Corporal (IMC) de seus praticantes. Participaram do presente estudo 25 mulheres com idade superior a 40 anos participantes iniciantes do Programa de Exercício Físico na Atenção Básica da cidade de Rio Claro-SP. As atividades foram realizadas com frequência de três vezes por semana, em sessões de 60 minutos. Foram realizadas três análises laboratoriais (início, após 4 meses e um ano de intervenção) das variáveis bioquímicas (glicose, triglicérides, HDL, LDL, e colesterol total). Os principais resultados do presente estudo demonstraram que após quatros meses de intervenção a circunferência abdominal e o LDL apresentaram menores valores do que no início do programa. Entretanto, após um ano de intervenção a circunferência do quadril, abdominal, LDL, glicose e colesterol total apresentaram maiores valores do que quando comparado com os valores após os 4 meses. Com base nos resultados antropométricos percebe-se que houve melhores resultados aos quatro meses de intervenção do que com um ano de intervenção. Provavelmente o que ocorreu no caso do presente estudo se deve pela...
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Pós-graduação em Agronomia (Produção Vegetal) - FCAV