Preparação e caracterização de vidros contendo nanopartículas de Ag

This work consists of preparation and characterization of glasses containing transition noble metals and the study of optical properties of such materials. The glasses were prepared by quenching of the glass melt followed by heat treatment and polishing of the monoliths. The structural characterization of glasses was made using differential thermal analysis, X-ray, Raman and infrared spectroscopies, while the optical properties were studied by UV-Vis and M-Lines spectroscopies. Preliminary results have shown that the color of the glasses is dependent on both concentration of silver and the melting temperature of the melt. Controlled heat treatments have been used to induce the crystallization of Ag nanoparticles within the glass. The study of crystallization was accompanied by electron microscopy and UV-Vis spectroscopy. Data from electron diffraction, as well as chemical analysis, EDX, were obtained using a transmission electron microscope. EDX data have shown that the atomic percentage of Ag is higher on the nanoparticle. X-ray diffraction was used in order to characterize the composition of the crystals and cubic AgCl was identified as the main crystallized nanophase obtained after annealing

Aplicação de adesivos estruturais em painéis de carros

The automobile industry is increasingly interested in reducing vehicle weight for greater speed, lower fuel consumption and emissions, through innovation of materials and processes. One way to do this is to seek the replacement of conventional processes by the use of structural adhesives. Structural adhesives are highly resistant materials, which can replace rivets, bolts and welds allowing the substrate / adhesive assemble is stronger than the substrate itself. One of the major advantages of gluing with respect to welding is its esthetic appearance, since it does not leave marks. For this reason, parts to be soldered require a minimum thickness so that the marks do not appear, since the pieces from gluing have no restriction as to the thickness. By replacing the vibration welding process for gluing process of the instrument panel parts of an automobile, one obtains a reduction of the thickness of the parts and therefore it decreases the weight of the car. This work aims to study the various structural adhesives that already exist on the market to be applied on the instrument panel. The mechanical test performed to measure the maximum adhesive strength was the Lap Shear Test at 23°C (room temperature), -35°C and 85°C. The types of adhesives used were the hot-melt and the bi-component. By the results obtained, it is in favor using the bi-component for application to the union of instrument panel parts

Obtenção e caracterização de compósitos nanoestruturados de poli(sulfeto de fenileno) reforçados com nanotubos de carbono

Pós-graduação em Engenharia Mecânica - FEG

Implantes nanotopograficamente modificados pela ação do laser Yb-YAG

Titanium has proven its suitability as an implant material in surgery over many years. Excellent biocompatibility and corrosion resistance are outstanding features. Implant surfaces always causes concern and interest in scientific communities, due to its close relationship with the time required for osseointegration. Surface modification can be performed by several methods, being laser irradiation one of them. Titanium implants with two different surfaces were inserted in rabbits: Group I (G-I: machined surface, control group), and group II (G-II: laser irradiated, test group) being processed 30 and 60 days after surgery for histological analysis. Surface characterization was performed with SEM-EDS, contact angle measurement, and mean roughness (Ra) parameters. Surface analysis in the GII group showed a nanomorphology affected by melt and quick solidification zones following laser irradiation (SEM), as well as total wettability and Ra mean values significantly higher than in the G-I group. The laser treatment resulted in a homogenized, porous surface, with increased surface area and volume. Histological analysis of bone-implant contact linear extension (BIC) showed better results in G-II at 30 days (39.26 ± 18.23 and 68.41 ± 13.68 for G-I and G-II groups, respectively). Titanium implants modified by laser irradiation showed important features that may accelerate early osseointegration.

Quantum Aspects of Solitons and Deformations on Ad'S IND. 4'x C'P POT.3' ('S POT. 7')

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

EStudo fundamental da interação de nanopartículas metálicas com íons terras raras em vidros e vitrocerâmicas para aplicações na região do infravermelho

Pós-graduação em Química - IQ

Fabricação de membranas fibrosas de compósito PVDF/TIO2 pelo método de fiação por sopro em solução

Pós-graduação em Ciência dos Materiais - FEIS

Electrical and Thermal study of carbon nanotubes reinforced poly (phenylene sulfide) nanostructured composites

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

Third-order nonlinearities and other properties of molybdenum lead-pyrophosphate glass

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efficiency comparison of hyperbranched polymers as toughening agents for a one-part epoxy resin

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

Estudo da cinética de decomposição de compósitos nanoestruturados de poli (sulfeto de fenileno) reforçados com nanotubos de carbono

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

Characteristics of PbO-BiO1.5-GaO1.5 glasses melted in SnO2 crucibles

PbO-BiO 1.5-GaO 1.5-based glasses are good candidates for optical applications, because of some of their interesting characteristics, such as high refraction indices and high transmission in the ultraviolet (UV), visible (VIS), and infrared (IR) regions. A limited stage in the processing of these glasses is the corrosion that is caused by the melt in all currently used conventional crucibles, such as noble metals (platinum or gold) and Al 2O 3. The absorption of crucible material by the glass composition may reduce the transmission level, the cutoff in the UV-VIS, and IR regions, and the thermal stability. In this study, a SnO 2 crucible has been tested for PbO-BiO 1.5-GaO 1.5 molten glass. Optical and thermal analyses show, in some cases, advantages over the use of platinum and Al 2O 3 crucibles. A visible cutoff value of 474 nm has been measured, and a longer melting time (850°C for 4 h) results in a significant reduction of the O-H absorption band at 3.2 μm.

Caracterização fisiológica, bioquímica e anatômica em genótipos de algodoeiro herbáceo (gossypium hirsutum l.var. latifolium hutch) em função da aplicação de cloreto de mepiquat

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação energética do uso de lenha e cavaco de madeira para a produção de energia em agroindústria seropédica

The aim of this paper was to perform an energy assessment of firewood and woodshaving use for energy generation in sericulture agroindustry boilers. In this research, we used a boiler from a silk spinning factory located in the city of Duartina, São Paulo, Brazil, that currently uses eucalyptus firewood as fuel to generate water vapour used in silk fiber production. In the studied fuels utilization system energy consumption structure development, we considered energy input in Megajoule (MJ) by type, source and form involved in several firewood use technical itinerary operations, as well as in woodshaving use technical itinerary operations. From these fuels utilization built structure, we performed a firewood- and woodshaving-generated energy input comparative analysis, in Megajoule/hour (MJ.h-1), to produce 2.968,80 kg.h-1 of vapour, which is the boiler average production, during the following years: 2004, 2005, and 2006. The energy analysis results revealed that to replace eucalyptus firewood with woodshaving is something possible in the boiler, reducing total energy consumption approximately by 21%.

Síntese e caracterização espectroscópica de novos vanadosilicatos utilizando templates orgânicos derivados de piperidinas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)