EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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3 resultados
Resultados da Pesquisa
Item SEM, EDX, Infrared and Raman spectroscopic characterization of the silicate mineral yuksporite.(2015) Frost, Ray Leslie; López, Andrés; Cipriano, Ricardo Augusto Scholz; Theiss, Frederick L.; Romano, Antônio WilsonThe mineral yuksporite (K,Ba)NaCa2(Si,Ti)4O11(F,OH) H2O has been studied using the combination of SEM with EDX and vibrational spectroscopic techniques of Raman and infrared spectroscopy. Scanning electron microscopy shows a single pure phase with cleavage fragment up to 1.0 mm. Chemical analysis gave Si, Al, K, Na and Ti as the as major elements with small amounts of Mn, Ca, Fe and REE. Raman bands are observed at 808, 871, 930, 954, 980 and 1087 cm 1 and are typical bands for a natural zeolite. Intense Raman bands are observed at 514, 643 and 668 cm 1. A very sharp band is observed at 3668 cm 1 and is attributed to the OH stretching vibration of OH units associated with Si and Ti. Raman bands resolved at 3298, 3460, 3562 and 3628 cm 1 are assigned to water stretching vibrations.Item An SEM, EDS and vibrational spectroscopic study of the silicate mineral meliphanite (Ca,Na)2Be[(Si,Al)2O6(F,OH)].(2015) Frost, Ray Leslie; López, Andrés; Theiss, Frederick L.; Romano, Antônio Wilson; Cipriano, Ricardo Augusto ScholzThe mineral meliphanite (Ca,Na)2Be[(Si,Al)2O6(F,OH)] is a crystalline sodium calcium beryllium silicate which has the potential to be used as piezoelectric material and for other ferroelectric applications. The mineral has been characterized by a combination of scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and vibrational spectroscopy. EDS analysis shows a material with high concentrations of Si and Ca and low amounts of Na, Al and F. Beryllium was not detected. Raman bands at 1016 and 1050 cm 1 are assigned to the SiO and AlOH stretching vibrations of three dimensional siloxane units. The infrared spectrum of meliphanite is very broad in comparison with the Raman spectrum. Raman bands at 472 and 510 cm 1 are assigned to OSiO bending modes. Raman spectroscopy identifies bands in the OH stretching region. Raman spectroscopy with complimentary infrared spectroscopy enables the characterization of the silicate mineral meliphanite.Item A vibrational spectroscopic study of the silicate mineral pectolite – NaCa2Si3O8(OH).(2015) Frost, Ray Leslie; López, Andrés; Theiss, Frederick L.; Romano, Antônio Wilson; Cipriano, Ricardo Augusto ScholzThe mineral pectolite NaCa2Si3O8(OH) is a crystalline sodium calcium silicate which has the potential to be used in plaster boards and in other industrial applications. Raman bands at 974 and 1026 cm 1 are assigned to the SiO stretching vibrations of linked units of Si3O8 units. Raman bands at 974 and 998 cm 1 serve to identify Si3O8 units. The broad Raman band at around 936 cm 1 is attributed to hydroxyl deformation modes. Intense Raman band at 653 cm 1 is assigned to OSiO bending vibration. Intense Raman bands in the 2700–3000 cm 1 spectral range are assigned to OH stretching vibrations of the OH units in pectolite. Infrared spectra are in harmony with the Raman spectra. Raman spectroscopy with complimentary infrared spectroscopy enables the characterisation of the silicate mineral pectolite.