Pyrolysis and auto-gasification of black liquor in presence of ZnO: An integrated process for Zn/ZnO nanostructure production and bioenergy generation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Piroxicam encapsulated in liposomes: Characterization and in vivo evaluation of topical anti-inflammatory effect

Liposomes of soya phosphatidylcholine, cholesterol, and stearylamine (molar ratio 6/3/1) and 0.1% alpha-tocopherol were prepared by the extrusion of multilamellar vesicles through 0.2-mu m polycarbonate membrane. Liposomes were characterized by electron transmission microscopy, and the mean structure diameter was 278 nm. The encapsulation efficiency obtained was 12.73%. The topical anti-inflammatory effect was evaluated in vivo by the cotton pellet granuloma method. We analyzed free piroxicam at 4 mg/kg, piroxicam encapsulated in liposomes added to 1.5% hydroxyethylcellulose (HEC) gel at 1.6 mg/kg, and piroxicam encapsulated in liposomes added to HEC gel at 4 mg/kg; the inhibition of inflammation obtained was 21.1%, 32.8%, and 47.4%, respectively. These results showed that the encapsulation of piroxicam produced an increase of topical anti-inflammatory effect, suggesting that the inhibition of inflammation can be obtained with lower drug concentrations.

Columnar microstructure of nanocrystalline Ga1-xMnxN films deposited by reactive sputtering

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

A combination of implicit and adaptative upwind tools for the numerical solution of incompressible free surface flows

This paper is concerned with the numerical solutions of time dependent two-dimensional incompressible flows. By using the primitive variables of velocity and pressure, the Navier-Stokes and mass conservation equations are solved by a semi-implicit finite difference projection method. A new bounded higher order upwind convection scheme is employed to deal with the non-linear (advective) terms. The procedure is an adaptation of the GENSMAC (J. Comput. Phys. 1994; 110: 171-186) methodology for calculating confined and free surface fluid flows at both low and high Reynolds numbers. The calculations were performed by using the 2D version of the Freeflow simulation system (J. Comp. Visual. Science 2000; 2:199-210). In order to demonstrate the capabilities of the numerical method, various test cases are presented. These are the fully developed flow in a channel, the flow over a backward facing step, the die-swell problem, the broken dam flow, and an impinging jet onto a flat plate. The numerical results compare favourably with the experimental data and the analytical solutions. Copyright (c) 2006 John Wiley & Sons, Ltd.

Vibrational and Thermal Properties of Crystalline Topiramate

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da degradação ambiental nas propriedades de cisalhamento de compósitos PPS/fibra de carbono

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

Avaliação do comportamento em fadiga de juntas estruturais de ligas de Al2024T3 coladas com adesivo epóxi

Ligas de alumínio são extensamente usadas em partes aeronáuticas devido às boas propriedades mecânicas e baixa densidade. Estas partes devem ser unidas para formar conjuntos maiores. Uma junta estrutural é definida como um segmento de estrutura que provê um meio de transferir carga de um elemento estrutural para outro. A maioria das juntas aeronáuticas é mecanicamente fixada com múltiplos prendedores (parafusos ou rebites). Estas juntas apresentam uma alta concentração de tensões ao redor do prendedor, porque a transferência de carga entre elementos da junta acontece em uma fração da área disponível. Por outro lado, as cargas aplicadas em juntas adesivas são distribuídas sobre toda a área colada e reduz os pontos de concentração de tensão. Juntas são a fonte mais comum de falhas estruturais em aeronaves e quase todos os reparos envolvem juntas. Portanto, é importante entender todos os aspectos de projeto e análise de juntas. O objetivo deste trabalho é comparar estaticamente juntas estruturais de ligas de Al2024-T3 em três condições: juntas mecanicamente rebitadas, juntas coladas e uma configuração híbrida rebitada e colada. Foi usada a norma NASM 1312-4 para confecção dos corpos-de-prova. Além disso, foram conduzidos testes de fadiga, sob amplitude de carregamento constante e razão de tensão igual a 0,1 para avaliar a eficiência dos elementos estruturais durante sua vida em serviço. Os resultados mostraram que a configuração híbrida apresenta maior resistência estática e uma vida em fadiga superior à configuração colada.

Production of a low young modulus titanium alloy by powder metallurgy

Titanium alloys have several advantages over ferrous and non-ferrous metallic materials, such as high strengthto-weight ratio and excellent corrosion resistance. A blended elemental titanium powder metallurgy process has been developed to offer low cost commercial products. The process employs hydride-dehydride (HDH) powders as raw material. In this work, results of the Ti-35Nb alloy sintering are presented. This alloy due to its lower modulus of elasticity and high biocompatibility is a promising candidate for aerospace and medical use. Samples were produced by mixing of initial metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by isochronal sintering between 900 up to 1600 °C, in vacuum. Sintering behavior was studied by means of microscopy and density. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. Samples sintered at high temperatures display a fine plate-like alpha structure and intergranular beta. A few remaining pores are still found and density above 90% for specimens sintered in temperatures over 1500 °C is reached.

Preparation of Ni-Ti-Mo and Ni-Ti-Mo-Zr Alloys by High-Energy Ball Milling and Subsequent Hot Pressing

This work discusses on the preparation of Ni-45Ti-5Mo, Ni-40Ti-10Mo and Ni-46Ti-2Mo-2Zr (at-%) alloys by high-energy ball milling and hot pressing, which are potentially attractive for dental and medical applications. The milling process was performed in stainless steel balls (19mm diameter) and vials (225 mL) using a rotary speed of 300rpm and a ball-to-powder weight ratio of 10:1. Hot pressing under vacuum was performed in a BN-coated graphite crucible at 900 degrees C for 1 h using a load of 20 MPa. The milled and hot-pressed materials were characterized by X-ray diffraction, electron scanning microscopy, and electron dispersive spectrometry. Peaks of B2-NiTi and Ni4Ti3 were identified in XRD patterns of Ni-45Ti-5Mo, Ni-40Ti-10Mo and Ni-46Ti-2Mo-2Zr powders milled for 1h. The NiTi compound dissolved small Mo amounts lower than 4 at%, which were measured by EDS analysis. Moreover, it was identified the existence of an unknown Mo-rich phase in microstructures of the hot-pressed Ni-Ti-Mo alloys.

Mechanical properties of HIPS/sugarcane bagasse fiber composites after accelerated weathering

The effect of accelerated weathering on the visual appearance and on mechanical properties of high impact polystyrene (HIPS) as well as HIPS reinforced with mercerized and bleached sugarcane bagasse fibers composites are investigated. After accelerated weathering period of 900 h, under UV-B radiation and moisture regular cycles, changes in mechanical properties are investigated by tensile tests. Materials fracture surfaces are investigated by scanning electron microscopy (SEM). The study showed that the exposure time was sufficient to change the visual appearance of HIPS as the composites. From this study, it was observed that composites reinforced with bleached fibers are less susceptible to accelerated weathering exposure than composites reinforced with mercerized fibers, which is explained by the higher amount of lignin present in mercerized fibers. (C) 2010 Published by Elsevier Ltd. Selection and peer-review under responsibility of [name organizer]

Electrolytic Balance in Broiler Chicks During the First Week of Age

Foram conduzidos dois experimentos, utilizando-se 712 pintos de corte para avaliar o efeito do balanço eletrolítico (Na+K-Cl) em rações pré-iniciais (1-7 dias) de frangos de corte. As rações à base de milho e farelo de soja, com 21,5 % de proteína e 2.900 kcal EM/kg, foram oferecidas à vontade. No experimento I, o nível de K foi fixado e os níveis de Na e Cl foram manipulados, em 4 tratamentos com 8 repetições de 16 aves cada. No experimento II, níveis mais elevados de Na e K foram usados, com 4 tratamentos e 5 repetições de 10 aves cada. em ambos os experimentos, os balanços eletrolíticos foram de 40; 140; 240 e 340 mEq/kg de ração. O balanço eletrolítico causou um efeito quadrático no ganho de peso e na conversão alimentar e um aumento linear no consumo de alimento quando o balanço eletrolítico foi aumentado pela suplementação de Na, indicando que esse íon estimula o consumo de alimento das aves nesse período. Porém, o consumo de alimento foi máximo em 202 mEq/kg, quando os níveis de K e Na foram simultaneamente aumentados na dieta, indicando que o limite superior de consumo de alimento é deprimido em função do K em excesso. O balanço eletrolítico ideal foi entre 246 e 277 mEq/kg obtidos pela manipulação dos níveis de Na e Cl.

Photopyroelectric spectroscopy of polyaniline films

Photopyroelectric spectroscopy (PPES), in the 400 < lambda < 900 nm wavelength range, was used to study thermal properties of differently doped polyaniline (PAN) films. The photopyroelectric intensity signal V-n(lambda) and its phase F-n(lambda) were independently measured, as well as the intensity V-n(f) and the phase F-n(f) (f being the chopping frequency) for a given A of the saturation part of the PPES spectrum. Equations of both the intensity and the phase of the PPES signal, taking into account the thermal and the optical characteristics of the PAN films and the pyroelectric detector, were used to fit the experimental results. From the fittings we obtained, with great accuracy, the values of thermal conductivity k and thermal diffusivity coefficient a of PAN films of different doping degrees. It was observed that, in contrast with the strong doping-dependence of the electrical conductivity, the thermal parameters of PAN films remained practically unchanged under doping. This apparent discrepancy is explained by the granular metal model of doped PAN. (C) 2000 John Wiley & Sons, Inc.

Estudo da viabilização do uso da mistura híbrida ferrocarbonila / ferrita de NI0,5Zn0,5Fe2o4 como material absorvedor de radiação eletromagnética

Were synthesized ferrites of NiZn on systems Ni0,5Zn0,5Fe2O4, the precursors citrate method. The decomposition of the precursors was studied by thermogravimetric analysis and spectroscopy in the infrared region, the temperature of 350°C/3h. The evolution of the phases formed after calcinations at 350ºC/3h, 600, 1000 and 1100ºC/2h was accompanied by X-ray diffraction using the Rietveld refinement method for better identification os structures formed. Was observed for samples calcined at different temperatures increased crystallinity with increasing calcination temperature, being observed for the samples calcined at 900 and 1100 º C/2h was the precipitation of a secondary phase, the phase hematite. The ferrocarbonila of industrial origin was analyzed by X-ray diffraction and Rietveld for the identification of its structure. The carbonyl iron was added NiZn ferrite calcined at 350ºC/3h, 600, 900, 1000 and 1100ºC/2h to the formation of hybrid mixtures. They were then analyzed by Xray diffraction and Rietveld. The NiZn ferrite and ferrocarbonila as well as the hybrid mixtures were subjected to analysis of scanning electron microscopy, magnetic measurements and reflectivity. The magnetic measurements indicated that the ferrite, the ferrocarbonila, as well as hybrid mixtures showed characteristics of soft magnetic material. The addition of ferrocarbonila in all compositions showed an increase in the results of magnetic measurements and reflectivity. Best result was observed in the increase of the magnetization for the hybrid mixture of Ferrocarbonila / ferrite of NiZn calcined at 600ºC/2h. The mixture Ferrocarbonila / ferrite calcined 1000°C/2h presented better absorption of electromagnetic radiation in the microwave

Influence of thermal annealing treatment in oxygen atmosphere on grain boundary chemistry and non-ohmic properties of SnO2 center dot MnO polycrystalline semiconductors

The present work studied the influence of thermal treatment in oxygen rich atmosphere on heterogenous junctions in Mn-doped SnO2 polycrystalline system presenting varistor behavior. The samples were prepared by conventional oxide mixture methodology, and were submitted to heat treatment in oxygen rich atmosphere at 900 degrees C for 2h. The samples were characterized by X-ray diffraction, scanning electron microscopy, dc and ac electrical measurements. The results showed that there is an evident relationship between the microstructure heterogeneity and non-ohmic electrical properties. It was found that for this SnO2 center dot MnO-based varistor system the heat treatment in oxygen rich atmosphere does not necessarily increase the varistors properties, which was related to the decrease in the grain boundary resistance. The results are compared with Co-doped SnO2 varistors and ZnO based varistors. (C) 2008 WILEY-VCH Verlay GmbH & Co. KGaA, Weinheim.