The structure and optical dispersion of the refractive index of tellurite glass

The structure and optical properties of a 80TeO(2)-(20-x)Li(2)O-xTiO(2) glass system where x = 0, 5, 10, and 15 mol% has been investigated using FTIR spectroscopy and Brewster angle measurements. The sample preparation, linear refractive index and density measurements, and infrared spectroscopic analysis are described. The refractive index and density of the studied tellurite glass samples increase when the amount of Ti in the glass is increased. The dispersion of the phase refractive index was analyzed using Wemple's model. The dispersion energy E(d) is significantly affected by the addition of Ti to TeO(2)-based glass. The analysis of FTIR spectra indicate a Te coordination change that is in agreement with the increase of the Te coordination number determined from dispersion data using Wemple's equation. (C) 2011 Elsevier B.V. All rights reserved.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Ciência e tecnologia no Brasil Imperial Guilherme Schüch, Barão de Capanema (1824-1908) Science and technology in Imperial Brazil Guilherme Schüch, Baron of Capanema (1824-1908)

O engenheiro e naturalista Guilherme Schüch de Capanema foi, sem dúvida, um expoente da elite Imperial. Circulou por importantes espaços institucionais científicos e técnicos, tendo atuado de forma bastante significativa para a implementação de uma cultura técnico-científica no Brasil e o conseqüente fortalecimento da engenharia e dos engenheiros. Entretanto, Capanema ainda permanece, assim como quase todos os cientistas do Segundo Império, um "desconhecido mal conhecido". O presente trabalho, contudo, não se propõe fazer sua extensa biografia, mas analisar e ressaltar aspectos de sua obra, relacionandoos a sua formação universitária e a sua prática enquanto engenheiro e naturalista.<br>Guilherme Schüch de Capanema was a prominent member of the Brazilian imperial elite. He belonged to several important institutional loci giving his valuable contribution to the implementation of a technical-scientific culture in Brazil, and therefore to the strengthening of both the field of engineering and the engineers. However, Capanema still remains an .unknown not well known., as do the majority of the scientists of the Second Empire. This paper analyzes and stresses aspects of his professional and academic life, related to his university education, and to his practice as engineer and naturalist