10 resultados para grupos de pesquisa

em Repositório Institucional da Universidade Estadual de São Paulo - UNESP


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

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Natural fibers have been highlighted as a renewable material that can replace materials from oil and its derivatives. In this context, Brazil becomes the perfect setting because of the diversity of fibers found in its territory, such as sugarcane, sisal, rice, cotton, coconut, pineapple, among others. The paineiras (Chorisia speciosa St. Hil) are typically Brazilian trees, which produce paina as fruit. These fruits are still little studied as a source of lignocellulose by research groups. This project aimed obtaining and characterization of cellulose nanofibers from the fibers from the paina fibers. Obtaining nanocellulose is practically made through simplified chemical processes. First, was performed out pre-treatments to removal of waxes, lignin and hemicellulose. The first stage of pre-treatment was carried out by alkaline aqueous solution of sodium hydroxide (NaOH) at 5wt%, where the fibers were under constant agitation for 1h at 70°C. Through alkali treatment it was possible to remove most of the lignin, hemicellulose, waxes and extractives. After the alkaline treatment was done bleaching with an aqueous solution of sodium hydroxide (NaOH) to 4wt% and hydrogen peroxide (H2O2) to 24wt% 1:1 during 2h with constant stirring to 50 °C. Through bleaching was possibe to remove residual lignin, and got cellulose with 72% of crystallinity. Nanocellulose of paina fibers was extracted using different conditions of acid hydrolysis with sulfuric acid (H2SO4) to 50wt%. After acid hydrolysis, the suspensions were centrifuged during 30 min and dialyzed in water to remove excess acid until neutral pH (6-7). Then the suspensions were passed by ultrasonification in an ultrasound 20 kHz during 1h in an ice bath. Untreated, alkalinized and bleached fibers as well as cellulose nanoparticles were characterized by the techniques of thermogravimetry ... (Complete abastract click electronic access below)

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The theme of the reading in the first year of the literacy cycle has become recurrent in academic papers, research groups, discussion forums, conferences etc. and raised different positions depending on the theoretical framework with which it is studied. While it is granted that reading instruction this school year is to ensure the ability to encode and decode and learn and understand the meanings and the meanings of what we read. In this work, it formed a general objective to investigate how reading skills are being developed in the classroom and the strategies used to develop decoding and understanding of meanings. The question that formed the north to the survey was as follows: The strategies and procedures being used in the teaching of reading in the early literacy process develop the coding and decoding skills beyond the grasp and understanding of the meanings of ideas? The specific objectives were established: a) investigate how is the teaching of reading in the first grade of elementary school; b) identify the teaching strategies and the design of reading and reader that the teacher of the class has observed and relate it to the way he teaches; c) verify that the teaching of reading in the first year of the literacy process, develop the early reading skills, decoding, and favors the development of the apprehension and understanding of the meanings of what we read. The methodology included field research, from a qualitative interpretation approach and had as direct data source the natural environment in which the teaching of reading has been developed. The work then displays data results analyzed in the light of literacy concepts distinguished by Soares (2011), and reading by Silva (1983), Foucambert (1994), Solé (1998), among others. The results were extracted inferences and interpretations. It is hoped that this work raises in literacy teachers, reflections on the teaching of reading in the literacy cicle, in order to establish the...

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)