Deciphering the weathering processes using environmental mineralogy and geochemistry: Towards an integrated model of laterite and podzol genesis in the Upper Amazon Basin

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

Tracing source and evolution of suspended particles in the Rio Negro Basin (Brazil) using chemical species of iron

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Podzolization as a deferralitization process: dynamics and chemistry of ground and surface waters in an Acrisol-Podzol sequence of the upper Amazon Basin

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

Red Mud from Brazil: Thermal Behavior and Physical Properties

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

Structural and dielectric characterization of praseodymium-modified lead titanate ceramics synthesized by the OPM route

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

Influence of particle size on the properties of Pt-Ru/C catalysts prepared by a microemulsion method

Pt-Ru/C nanocatalysts were prepared by a microemulsion method using different values of water/surfactant molar ratio in order to get different particle sizes. Crystallite sizes and structural properties were determined by X-ray diffraction. Particle size and distribution were characterized by transmission electron microscopy and average composition was determined by energy-dispersive X-ray analysis. Thermogravimetric analysis was used to estimate the amount of supported metals. Differential scanning calorimetry measurements indicated the presence of hydrous ruthenium oxides in the as-prepared catalysts. Results for the oxidation of adsorbed CO as well as for methanol oxidation revealed significant differences in the behavior of the prepared catalysts. All together, the results demonstrate that the variation of particle size produces changes in other properties of the Pt-Ru/C catalysts and that to establish direct correlations between electrocatalytic activity and particle size is not possible because the effects of the different parameters cannot be separated. (c) 2007 the Electrochemical Society.

Estudo do biomaterial Ti-6Al-4V empregando-se técnicas eletroquímicas e XPS

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

Electrochemical behavior of Ti-Mo alloys applied as biomaterial

Electrochemical investigation on the as-cast Ti-Mo alloys (4-20 Mo wt.%) applied as biomaterials in Na2SO4 and Ringer physiological solutions is reported. Analyses of the open-circuit potential indicated that all alloys present spontaneous passivation. SEM and cyclic voltammograms obtained in the Ringer solution showed that the samples studied do not present pitting corrosion at potentials up to 8 V (SCE), indicating high corrosion resistance. Open-circuit potential profiles of the anodic oxides growth in both solutions show that the presence of chloride ions during the anodization does not influence the oxides' chemical stability, and also clearly indicate that adding Mo to pure Ti improves the stability of the anodic oxides. All these results suggest Ti-Mo alloys promissory to be applied as biomaterials. (c) 2008 Elsevier Ltd. All rights reserved.

Electrochemical stability and corrosion resistance of Ti-Mo alloys for biomedical applications

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

Black and green pigments based on chromium-cobalt spinels

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevance of Electronic Effects on the Yield of CO2 from Methanol Oxidation

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

Photo-electrochemical investigation of anodic oxide films on cast Ti-Mo alloys I. Anodic behaviour and effect of alloy composition

The anodic behaviour of cast Ti-Mo alloys, having different Mo contents (6-20 wt.%), was investigated in acidic and neutral aerated aqueous solutions. All sample showed a valve-metal behaviour, owing to formation and thickening of barrier-type anodic oxides displaying interference colours Growth kinetics. of passive films is influenced by both anodizing electrolyte and composition of the starting alloy. This last parameter was found to change also the solid-state properties of the films, explored by photoelectrochemical and impedance spectroscopy experiments. Thicker films (U(f) = 8 V/MSE) grown on alloys richer in Mo showed more resistive character and a photocurrent sign inversion under negative bias, that revealed an insulating character, whereas corresponding films grown on alloys with lower Mo content, as well as thinner films, behaved as n-type semiconductors. Results are discussed in terms of formation of a mixed Ti-Mo oxide phase. (C) 2008 Elsevier Ltd. All rights reserved

CuO urchin-nanostructures synthesized from a domestic hydrothermal microwave method

This letter reports the synthesis of CuO urchin-nanostructures by a simple and novel hydrothermal microwave method. The formation and growth of urchin-nanostructures is mainly affected by the addition of polyethylene glycol (PEG). The hierarchical malachite particles are uniform spheres with a diameter of 0.7-1.9 mu m. CuO urchin-nano structures were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FEG-SEM) and nitrogen adsorption (BET). The specific surface area of the CuO nanostructured microspheres was about 170.5 m(2)/g. A possible mechanism for the formation of such CuO urchin-nanostructures is proposed. (c) 2007 Elsevier Ltd. All rights reserved.

Novel Aspects of the Purpose-Built Materials Strategy: Evidence of Topographic Template Effect and Oriented Attachment Growth Mechanism

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

Corrosion and Wear Studies of Cr3C2NiCr-HVOF Coatings Sprayed on AA7050 T7 Under Cooling

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