278 resultados para efeitos de meio


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciências Fisiológicas - FOA

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Pós-graduação em Ciências Odontológicas - FOAR

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Fuel cells powered directly with ethanol (Direct Ethanol Fuel Cell-DEFC) are very attractive for the possibility of using a renewable fuel in the generation of clean energy. However, it is still necessary to deepen the understanding of catalytic processes and their dependence on the catalytic properties. This work proposes to study the catalytic activity of ethanol oxidation in an alkaline medium of Pd nanoparticles supported in carbon oxide hybrids using various transition metal oxides (MoO3, TiO2, WO3 and ZrO2). The materials prepared were characterized by techniques such as X-ray diffraction, transmission electron microscopy (TEM) and X-ray dispersive spectroscopy (EDX) to verify the structure, the distribution of particles in the supports and the presence of Pd on particles oxide. Experiments of X-rays absorption spectroscopy were carried out using soft X-rays (SXS) to evaluate the changes in the electronic properties of the Pd particles caused by interactions with different oxides. Measurements of cyclic voltammetry and potential sweeps of adsorbed CO oxidation allowed evaluating general aspects of the catalysts' electrochemical behavior and determining the electrochemically active area thereof. The catalytic performances of ethanol oxidation in alkaline medium were evaluated by electrochemical techniques (potential scan and chronoamperometry), and showed an improvement in activity with the addition of oxides in material containing only carbon, which was most pronounced for the catalyst containing TiO2. This improvement was predominantly associated with the electronic effects caused by the interaction of Pd on the support, causing a vacancy in the 4d band of Pd which, in turn, produces variations in adsorption energies of the species...

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The aim of this research was to apprehend the effects of text reading in S.'s writing productions, a child in literacy process. S. is a child who can't speak or write by her own due to a dystonic quadriplegic CP. S. communicates with Blissymbols which were introduced in a school-clinic in São Paulo city when she was six years old. At the same time the literacy process took place and she indicated symbols, letters and numbers in a board by scanning. The teacher related S.'s difficulties concerning reading activities, so a weekly activity was proposed by the speech therapist in the classroom. The teacher and her assistant participated in the activity. A cutout of the activity involving a book reading when S. was between eight years and seven months old and nine years and one month old was analysed. The research was based in Borges (2006) grounded in The Brazilian Interactionism according to De Lemos (1992; 1995 and others) and proposes a literacy process among students from the first series in a regular school by the reading of different texts. The activity guided by the speech therapist took place side by side with the literacy program guided by the teacher and resulted in various S's text productions. The data was collected through film transcriptions from the activities in the classroom and from materials produced by S. through the reading of the chosen book. These data integrates NALíngua-CNPq databases coordinated by Dr. Alessandra Del Ré whose aim is to investigate the language acquisition process. S.'s reading and writing acquisition occurred in a singular way, affected by the using of Blissymbols that became S.'s speech modality: a written-speech with symbols and alphabetic writing

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