998 resultados para Correntes eletricas - Aterramento


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Ribeira Valley, a region covered by the last continues area of the Atlantic Rain Forest in São Paulo State, in Brazil, is thus a preservation law and environmental control target, is now configurated as locus where emerge conflicts concerning economic and agricultural activities, particularly in places where befall public policies recognizing territorial rights – quilombo remnants, indigenous lands and sustainable development settlings. The research’s aim is to understand, considering each of these contexts, if and how a conservationist focus is assumed as a value and a strategy, connected to etnicity and traditionality, in order to actualize these social spaces.

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The theme of indigenism in Mariátegui’s thinking can only be understood as indigenous socialism. His original interpretation of Peruvian reality reveals a double heterodoxy, both from the standpoint of current indigenism and the socialist theory of his time. The first one defends exclusively the autochthon elements to face the imperialist power. The second one didn’t recognize the Latin American particularities to define the revolutionary duties. When Mariátegui states that the Peruvian socialism should be based on the remaining forms of indigenous agrarian communitarianism, he overcomes both (current indigenism and socialist theory) and offers a dialectical synthesis, condensed in a single proposition: Indigenous-American Socialism.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Current paper discusses manifestations of the sublime in Pedro Kilkerry´s poetry as one of the distinguishing characteristics within the Parnassian orientations predominant in his cultural context. The particular way that Kilkerry employs the sublime´s expedients demonstrates the dialogue of his poetry with Romantic ideals, whose traits in his lyrical stance are directly linked to Symbolist influence, far from traditional Parnassian models. The sublime in Kilkerry develops through an elliptical and suggestive language that demonstrates the impossibility of the ideal being directly expressed and shows the affinity of his poetic work with the idealist crisis that marks post-Romantic poetry and provides the basis on which the poetics of Modernity is structured. The poetry of Pedro Kilkerry develops within a complex zone of convergence between the models provided by the Parnassian aesthetic, Romantic idealism with an atavic presence to Symbolism, and the search for new answers to old idealistic concerns. The meeting of these three conflictive currents, perceptible in the manifestations of the sublime in Pedro Kilkerry´s poetry, demonstrates his lyrical sensitivity to the trends of Modernity.

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The question of the relationship between subject and object has been discussed and explored in several theoretical and methodological systems, showing resonances and disagreements about the possibilities of developing a science or a philosophical system to allow the construction of the knowledge about the world. Among these, the systems of two authors in particular are different, respectively, regarding the complexity and ontological taxonomic: Michel Foucault and Karl Marx. This work aims to discuss the objectivity and subjectivity in the work of these two thinkers, indicating some possible correlations. The discussions were about the concept of knowledge in Michel Foucault, difficulties experienced by its researchers to classify their work within a classical theoretical system and the difference of Marxist theory in relation to other research programs for not presenting the individual as the fundamental ontological entity. Foucault´s work influenced the process of restoration and redemption of Marxism by Marxists groups.

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The Frankfurt critical theory and the French post-structuralism are important lines of thought in the philosophy of education, which inspired several academic productions in recent decades. In the 1950s and 1960s, both opposed philosophical resistance against many types of totalitarianism. One big difference between the two lines of thought has been the critical of the dialectic considered an insufficient method to think about the difference (Deleuze) and the reaffirmation of a negative dialectic (Adorno). This article intends to analyze the thematic affinities and the differences of method between the thought of these two authors.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Superconductivity was discovered by the dutch physicist Heike Kamerlingh Onnes (1853

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Fabrication of optoelectronic devices requires the employment of at least one transparent electrode. Usually, commercially transparent electrodes have been made by deposition of indium tin oxide (ITO) films by RF-Sputtering technique. These commercial electrodes have sheet resistance of about 100 Ω/sq and optical transmittance of 77% at the wavelength of 550 nm. The poly(3,4-ethylenedioxythiophene):polystyrene-sulfonate (PEDOT:PSS) is an alternative material to fabricate transparent electrodes due to its high conductivity (about 600 S/cm) and solubility in water. Soluble conductive materials exhibits advantages for processing of electrode layers, however there is a disadvantage during devices fabrication once materials with the same solvent of the electrode material cannot be coated one over the other. Alternatively, organic/Silica hybrid materials prepared by sol-gel process allow producing bulks and films with high chemical durability. In order to obtain transparent electrodes with high chemical durability, we introduced a blended material comprising the high UV-VIS transparency of organic/Silica sol-gel material and a high conductivity polymer PEDOT:PSS. The organic/Silica sol was obtained using two different molar concentrations (1:1 and 4:1), of tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTS). Amounts of PEDOT:PSS solutions were added to the sol material, resulting in different weight fractions of sol and polymer. G:T/P:P were deposit onto glass substrates by spray-coating. In order to perform electrical characterization of the blended material, gold electrodes were thermally evaporated onto the films. The electrical characterization was performed using a Keithley 2410 source/meter unity and the optical characterization, using a Cary50 UV-Vis spectrophotometer. The absorption coefficient and electric conductivity of the different compositions blends, as function of the PEDOT:PSS concentration, were...

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Pós-graduação em Engenharia Mecânica - FEG

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Pós-graduação em Biologia Geral e Aplicada - IBB

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The development of electrocatalysts for the oxidation of methanol and ethanol is very important, because these alcohols may be used in the anode fuel cells which convert chemical energy directly into electrical energy with high efficiency, cleanly and with low noise. Thus, this study reports to the synthesis of nanocatalysts of PtAu supported on carbon by microemulsion method. The physical characterization of these catalysts is performed through the techniques of X-ray diffraction and transmission electron microscopy. The catalytic activity of the prepared materials was studied using conventional electrochemical techniques and also the technique of spectro-electrochemical in situ FTIR, which allows identification of intermediates and products of the reactions. From the x-ray diffraction, it was observed that the thermal treatment applied to catalysts favored incorporation of Au into the crystal lattice of Pt,that is, increased the formation of PtAu alloy. Micrographs indicated particle size about 3 nm to materials not heat treated and 9 nm to materials subjected to thermal treatment (heating at 150 ° C for 1h and 30 min in argon atmosphere). Current density oxidation of methanol on PtAu / C were superior to pure platinum. Spectroscopic results indicated the presence of formate in solution in 50:50 and the composition showed bands for CO2, indicating complete oxidation, in lower potential. During ethanol oxidation on the catalyst PtAu, the main product formed was acetate, product of incomplete oxidation. The good performance for methanol oxidation can be attributed to large amounts of oxygen species adsorbed on the catalyst surface, or an electronic effect.