Elaboration of boehmite nano-powders by spray-pyrolysis

Boehmite (gamma-AlOOH) synthesis have been investigated using a spray pyrolysis (SP) device starting from a stable sol of Al-tri-sec-butoxide peptized by nitric acid. Free spherical particles from 100 to 500 nm have been elaborated. Particles sub-structure is made of nano-crystalline boehmite with very small average crystallite size (one crystal cell along the b axis). The nano-crystalline boehmite synthesized by SP at low temperature (200 degrees C) is spontaneously dispersible in water without any surface treatment. Boehmite powder may be transformed to transition gamma-alumina by heat post-treatment. Powders of sub-micrometric and spherical gamma-alumina particles may also be synthesized by SP at 700 degrees C. (C) 2008 Elsevier B.V. All rights reserved.

Preparation and characterizations of Ba0.8Ca0.2TiO3 by complex polymerization method (CPM)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desempenho de frangos de corte de 1 a 21 dias de idade alimentados com rações contendo extrato de leveduras e prebiótico e criados em diferentes temperaturas

The performance of broilers reared at different temperatures and fed diet with or without yeast extract and/or prebiotic in the starter phase was evaluated. One thousand, four hundred and forty 1-d male Cobb-500 (R) were reared at different climatic chambers. The diets with or without yeast extract or prebiotic were fed only in the starter phase (1 to 7 days), and from the 8(th) day on all broiler were fed the same commercial diet. It was used a complete randomized experimental design, as a 3 x 2 x 2 factorial arrangement, with 3 rearing temperatures (high 34 +/- 1 degrees C, control 32 +/- 2 degrees C and low 27 +/- 2 degrees C), 2 yeast extract level (with or without) and 2 prebiotic level (with or without). High and low temperatures decreased the performance of brids at 7 and 21 days old. The inclusion of prebiotic in the pre-starter phase increased weight gain of birds under low temperature at 21 days old and the viability until 21 days old. The inclusion of yeast extract increase feed conversion at 21 days old.