Amorphous Oxides
Mostrando 1-12 de 22 artigos, teses e dissertações.
-
1. THEORETICAL UNDERSTANDING OF MORPHOLOGICAL DISTRIBUTION OF HYDROGEN IN AMORPHOUS CALCIUM SILICATE HYDRATE
Determining the morphological distribution of hydrogen atoms in calcium silicate hydrate phase (C-S-H) is of great concern but challenging. In this work, based on the stoichiometric composition of (CaO)1.7(SiO2)(H2O)1.8, a series of amorphous Ca1.7•Si•(O)3.7-x•(OH)2x•(H2O)1.8-x models are constructed using Monte Carlo method, where x represents the m
Quím. Nova. Publicado em: 20/07/2020
-
2. De-NOx Performance and Mechanism of Mn-Based Low-Temperature SCR Catalysts Supported on Foamed Metal Nickel
A series of manganese-based catalysts supported on foamed metal nickel (FMN) with various Mn/Ni ratios was prepared for low-temperature selective catalytic reduction (SCR) of NO with NH3 (NH3-SCR). The effects of calcination temperature, amount of added Mn, optimal operating conditions, and H2O on the elimination of nitrogen oxides (de-NOx) performance of ca
J. Braz. Chem. Soc.. Publicado em: 2018-08
-
3. Synthesis and characterization of novel ZrO2-SiO2 mixed oxides
In this study the mixed oxides ZrO2-SiO2, were synthesized by the sol-gel method with a molar ratio of 95:5 (Si/metal) and characterized by X-ray diffraction, absorption-desorption of N2, Fourier transform infrared spectroscopy, thermal gravimetric analysis, temperature-programmed desorption of ammonia, and acidity test by titration. The synthesized material
Mat. Res.. Publicado em: 15/04/2014
-
4. Caracterização térmica e estrutural de pós e filmes finos de BaTiO3 sintetizados via método Pechini / Thermal and structural characterization of powders and thin films of BaTiO3 synthesized by Pechini method
Amorphous oxides are chemical compositions whose atomic or molecular configuration does not follow a periodicity like it happens with crystals, which are essentially constituted by oxygen atoms, which has to be the most electronegative element, and other elements. The barium titanate (BaTiO3), amorphous oxide obtained through this work has tetragonal structu
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/02/2012
-
5. Platinum and nioubium based catalysts for the anode of polymer electrolyte membrane fuel cells fed with low molecular weight alcohols / Catalisadores a base de platina e nióbio para o ânodo da célula a combustível de membrana trocadora de prótons alimentada com alcoóis de baixa massa molecular
In this work, the methanol and ethanol electrochemical oxidation reactions are studied on platinum (Pt) and niobium (Nb) catalysts supported on high surface area carbon. The selected materials were PtNb/C, Pt-Nb2O5(amorphous) /C e Pt-Nb2O5(crystalline) /C, using as reference for comparison purposes the commercial catalyst 20% Pt-C E-TEK. The catalysts were p
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/01/2012
-
6. Obtenção e caracterização de materiais catalisadores da oxidação de contaminantes em solução aquosa
"Sn" and "Al" materials, with different reasons in Sn/Al2O3 mass were obtained, characterized and tested as catalysts for the oxidation of indigo carmine dye. The characterization of the materials confirmed the presence of Sn (IV) in all samples. It was observed only one phase, the SnO2. The particle size obtained was 22 to 36 nm. The photocatalytic tests sh
Publicado em: 2010
-
7. Nanocomposites materials generated from a spray
The Spray Pyrolysis (SP) process has been employed at moderate temperature (470-970 K) for the synthesis of micro- and nano-particles of hydrated metal oxides and of related nanocomposites. It has been applied to iron nitrate solutions, without or with the addition of sodium chloride as a flux. After removal of the flux, nanocomposites of ferrihydrite (5Fe2O
Brazilian Journal of Physics. Publicado em: 2009-04
-
8. Desenvolvimento de filmes finos de óxidos condutores e transparentes de ZnO para aplicação em células solares
In this work, transparent and conducting undoped zinc oxide (ZnO) thin films were developed with transmittance and electrical resistivity appropriate for application as frontal contact in solar cells. Because of their chemical stability, good electro-optical properties, large band gap, abundance in nature and low toxicity, the ZnO films have emerged as one o
Publicado em: 2007
-
9. Análise da Conformidade e Caracterização da Matéria- Prima Empregada na Fabricação de Blocos Cerâmicos na Região Metropolitana de Salvador
The potential market of the metropolitan area of Salvador accounts for the estimated consumption of roughly 800 million horizontally perforated extruded clay bricks a year. The growing demand of consumers along with the competitiveness of the structural ceramic sector has driven forward a number of recent efforts and investments towards improving the quality
Publicado em: 2007
-
10. Avaliação de impactos ambientais nos tributários do lago Paranoá, Brasília - DF
The high level of urbanization in Distrito Federal in Brazil is contributing to modify the environment particularly the quality of surface water resources. The historical of environment aggression to the Paranoá Lake through urban expansion, land use and land occupation, is studied as environmental changes. In this work, physical-chemistry conditions and ge
Publicado em: 2007
-
11. Reduction of iron oxides by reaction with sodium borohydride / Redução de óxidos de ferro por reação com borohidreto de sódio
xviii The chemical reduction of transition metal ions in solution by action of the borohydride group ion has been applied by several researchers attempting to synthesize amorphous Fe-B alloys. In this project iron-oxide particles suspended in water, rather than ions in solution, were used for that purpose. The reducing chemical was chosen to be sodium borohy
Publicado em: 2005
-
12. Filmes finos de MoOx e NixMoOy : aplicação em microbaterias
The rapid growth of portable electronic devices with applications in distinct areas (telecommunications, medicine, engineering) as well as ambiental factors created a huge demand on compact, light, low cost power sources This demand stimulated the development of thin film technologies for the production of the main parts of batteries, generating the concept
Publicado em: 2003