"APLICAÇÃO DE JOGOS COMO UMA POSSÍVEL FERRAMENTA PARA A FORMAÇÃO DO PROFESSOR REFLEXIVO"

Este trabalho analisa a aplicação de jogos como possível estratégia para a formação inicial do professor reflexivo. Neste intuito, alunos do sétimo semestre do curso de Licenciatura em Química da UNIFEV (Centro Universitário de Votuporanga, São Paulo) foram orientados na aplicação de jogos na terceira série do Ensino Médio de uma Escola Pública de Votuporanga. Para tal, 43 licenciandos, divididos em 12 grupos de três ou quatro alunos, foram orientados a adaptarem jogos infanto-juvenis tradicionais aos conteúdos de Química. Como parte das atividades dos discentes, cada licenciando registrou diariamente as atividades em portfólios. As concepções/percepções/sensações manifestadas pelos estudantes após a primeira aplicação e as possíveis contribuições desta atividade para a formação de um professor reflexivo são apresentadas e discutidas

Synthesis of indium tin oxide nanoparticles by a nonhydrolytic sol-gel method

Indium tin oxide nanoparticles were synthesized in two different sizes by a nonhydrolytic sol-gel method. These powders were then transformed into ITO via an intermediate metastable state at between 300 and 600 ºC. The presence of characteristic O-In-O and O-Sn-O bands at 480 and 670 cm-1 confirmed the formation of ITO. The X-ray diffraction patterns indicated the preferential formation of metastable hexagonal phase ITO (corundum type) as opposed to cubic phase ITO when the reflux time was less than 3 h and the heat treatment temperature was below 600 ºC. Particle morphology and crystal size were examined by scanning electron microscopy

Fenilsilicato dopado com Eu III obtido pelo método sol-gel

In this work, we report the synthesis and the photoluminescence features of a Eu(III)-doped modified silica matrix obtained by the sol-gel method. The matrix was prepared by reaction between tetraethylorthosilicate and phenyltriethoxysilane alkoxide. The hydrolysis occurred using basic catalysis. The solids were treated at 100, 200 and 300 ºC during 4 h and the structure was determined by thermogravimetric analysis (TG/DTG), nuclear magnetic resonance (NMR 29Si and 13C), infrared spectroscopy (IR) and photoluminescence (PL). The PL spectra display the Eu(III) lines characteristic of the ion, 5D0 -> 7F J (J=0, 1, 2, 3, 4), the blue emission as ascribed in the silica matrix. The NMR and TG showed the stability of hybrid silica

b-diketonates of Eu3+, red phosphors, supported on sol-gel functionalised silica

Silica gel was functionalised with chloropropyl groups through the sol-gel process and then a beta-diketone was incorporated into the support. Afterwards, Eu3+ ion and its chelates of 1,10-phenantroline (phen) and 2,2'-bipyridine (bpy), red phosphors, were supported on such silica. Luminescence studies of Eu3+ bound to this new material have shown that there is an increase in the intensity of the emission when the ion is isolated by ligands in the silica matrix. The energy transfer from the ligands phen and bpy to Eu3+ ion was observed in the excitation spectra, which present new bands ascribed to the ligands and/or complex. The Eu3+-functionalised silica was characterised by TGA and FTIR. TGA analysis showed that there is a large loss of mass around 300 °C, which is ascribed to the organic part of the material. The FTIR spectra presented the vibration modes for Si-C and -CH2-. The luminescent properties of the ions surrounding the Eu3+ ion were studied. The decay curve displayed a bi-exponential behaviour, indicating that there is more than one site of Eu3+ on the surface of the silica

Synthesis and some properties of hybrid gels of titanium oxide containing europium (III)

In this work, we report the synthesis and properties of TiO2 and of an organic-inorganic hybrid of TiO2 where the inorganic network was obtained by hydrolysis (sol-gel process) of the titanium tetraisopropoxide precursor. Both materials were prepared and dried in air. The organic oligomer was synthesized by esterification between ethylene glycol and dipicolinic acid, using Eu3+ as probe. These materials were studied by luminescence and infrared spectroscopies, thermogravimetric analysis and X-ray diffraction. The results obtained for the hybrid material show the formation of two crystalline polymers. Eu3+ has been used as structural probe due to its photophysical properties and also as emission center for luminescent materials and the luminescence data indicate that Eu3+ occupies one kind of site that is isolated from water molecules and OH groups. (C) 1999 Elsevier B.V. B.V. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Estudo das condições de estocagem do bagaço de cana-de-açúcar por análise térmica

An evaluation was made of the properties of sugarcane bagasse during the storage process for subsequent burning in a boiler. Samples of bagasse were collected over a period of 150 days from the Caeté sugar mill (MG) at various points of the stockpile soon after the sugarcane was pressed to extract its juice, as well as from natural bagasse, dry and damp. Thermal analyses of the samples were carried out and the results indicated that, during the storage of bagasse, dry or damp, the biomass loses up to 32% of its calorific power, due to decomposition of the hemicellulose