Synthesis of KNbO3 nanostructures by a microwave assisted hydrothermal method

One-dimensional nanostructures of KNbO3 have attracted a great interest in the scientific community, mainly because of their promising application as nanoelectromechanical systems (NEMS). However, the synthesis of KNbO3 structures becomes complex due to the natural tendency to form non-stoichiometric potassium niobates. In this context, we report on the crystallization of one-dimensional KNbO3 nanostructures through the reaction between Nb2O5 and KOH under microwave-assisted hydrothermal synthesis (M-H). The use of this synthesis method made possible a very fast synthesis of singlecrystalline powders. Based on SEM, TEM and XRD characterizations, the influence of the synthesis time and the reactants concentration in the structure and morphology of the resultant KNbO3 was established. The conditions that favor the crystallization of nanofingers were determined to be small amounts of Nb2O5 and short reaction times. (C) 2008 Elsevier B.V. All rights reserved.

Time-based competitiveness in Brazil: whys and hows

The objective of the paper is to report research carried out over two years aiming at developing a framework to support the management of manufacturing organizations for whom reducing throughput time is strategically important, either because they compete based on short lead times or because they choose to pursue other objectives such as cost reduction by means of reducing their manufacturing cycle times. A step-by-step method is proposed based on the analyses of a number of Brazilian best practice cases (all manufacturing companies and all part of large multi-national corporations) and on the relevant literature.

Photoluminescence of nanostructured PbTiO3 processed by high-energy mechanical milling

This letter reports on a process to prepare nanostructured PbTiO3 (PT) at room temperature with photoluminescence (PL) emission in the visible range. This process is based on the high-energy mechanical milling of ultrafine PbTiO3 powder. The results suggest that high-energy mechanical milling modifies the particle's structure, resulting in localized states in an interfacial region between the crystalline PT and the amorphous PT. These localized states are believed to be responsible for the PL obtained with short milling times. When long milling times are employed, the amorphous phase that is formed causes PL behavior. An alternative method to process nanostructured wide-band-gap semiconductors with active optical properties such as PL is described in this letter. (C) 2001 American Institute of Physics.

Formation of beta-nickel hydroxide plate-like structures under mild conditions and their optical properties

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sol-gel synthesis of mesoporous CaCu3Ti4O12 thin films and their gas sensing response

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

High-pressure assisted sintering of Ti-20Si-10B and Ti-10Si-5B powders

This work presents the structural characterization of Ti-10Si-5B and Ti-20Si-10B (at-%) alloys produced by high-pressure assisted sintering. Sintering was performed in air at 1100 and 1200°C for 60 s using pressure levels of 5 GPa. Structural evaluation of sintered samples was conducted by means of scanning electron microscopy and energy dispersive spectrometry. Samples were successfully consolidated after sintering, which presented theoretical density values higher than 99%. The microstructures of the sintered Ti-10Si-5B and Ti-20Si-10B alloys revealed the presence of the TiSS, TiB, TiB2, Ti5Si3, Ti5Si4, TiSi, and TiSi2.phases. A small amount of Ti6Si2B was formed after high-pressure assisted sintering of the Ti-20Si-10B alloy (5GPa, 1100°C for 60 s) indicating that equilibrium structures were not achieved during short sintering times. No oxygen and carbon contamination was detected in structures of Ti-Si-B alloys after high-pressure sintering at 1100 and 1200°C without controlled atmosphere. © (2012) Trans Tech Publications, Switzerland.

Avaliação do potencial de compostos naturais (argila, turfa e carvão) na remoção do Chumbo (Pb) e da toxicidade de um efluente industrial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação físico-química e da atividade antibacteriana de soluções irrigadoras endodônticas e associações

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Eficácia do óleo de Melaleuca alternifolia sobre bactérias cariogênicas e sua citoxicidade sobre cultura de queratinócitos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Citotoxicidade trans-amelodentinária e alterações estruturais no esmalte após clareamento com géis caseiros a base de peróxido da carbamida

Pós-graduação em Reabilitação Oral - FOAR

Síntese, caracterização e aplicação de celulose funcionalizada com o ligante P-aminobenzóico em pré- concentração de íons metálicos

Pós-graduação em Química - IQ

Efeito do óleo de nim (Azadirachta indica A. Juss) no intestino médio de Ceraeochrysa claveri (Navás, 1911) (Neuroptera: Chrysopidae): estudo citoquímico, imunocitoquímico e ultraestrutural

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Europium-doped calcium titanate: Optical and structural evaluations

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Study of constructed wetlands effluent disinfected with ozone

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

Desidratação de polpa de manga em leito de espuma com e sem intermitência térmica

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