Materials Science Forum Vol. 958

Abstract: In this paper are presented both the fill factor of 0.75 and an efficiency approaching 14.64 % of solar cell, which were achieved, despite the non-optimized process. A new Cu-based additive of pastes were applied for formation of front contact on silicon solar cells. Front contact were screen-printed using commercial silver paste containing the CuXX additive prepared at laboratory. It is the world's first copper based paste appropriate for high-temperature production processes of front contact of the solar cell.

Abstract: The Pseudoboehmite is an aluminum compound used as an alumina precursor and it is produced by sol-gel process. The sol-gel process is a methodology to produce porous, vitreous or crystalline ceramics started by molecular precursors. Pseudoboehmite with high purity, high specific surface area and porous homogeneity was obtained by sol-gel process. The material was used to produce gamma-alumina with surface area ranging from 211.2-288.1m²/g. It was studied the effect of aging time, temperature of aging and poly (vinyl alcohol) addition in the synthesis.

Abstract: The world's energy production is generated mainly from fossil fuels, so it is important to develop fuels from renewable sources. Growing caution with the environmental impact imposes restrictions on emissions from the combustion of fossil fuels. With increasing human population and expanding economies in both developing and developed countries, there is an increase in energy consumption and production. The need arises to supply this high energy production with a renewable and reliable source fuel [1]. These facts have stimulated research by alternative sources for the development of renewable fuels. One of the most promising fuels is biodiesel, an alternative to petroleum diesel from high-quality renewable sources, which allows the replacement of fossil diesel oil without modifications to the vehicle's engine [2, 3]. In recent years, methyl esters of fatty acids derived from vegetable oil have gained considerable attention as alternative fuel [4, 5].

Abstract: This objective of this study was to produce organoclay, analyze it, and evaluate its use in the process of removing oil emulsion from an oil–water system. The organoclay was prepared by the direct method and was characterized using X-ray diffraction, Cation Exchange Capacity (CEC), and Infrared Spectroscopy (IV). A finite bath system was used to evaluate the effects on the removal capacity, using a stirring speed (A) of between 100 and 300 rpm and an initial concentration of oil-water solution (C₀) evaluated in the range of 100 to 500 mg/L. The XRD and infrared results indicated that CTAC was intercalated between the layers of Bofe clay. The percentage of oil removal from oil-in-water emulsions was between 55.99 and 96.62%. These results indicate that OC can potentially remove up to 97% oil from oil-in-water emulsions. Consequently, the OC could be considered an excellent medium for treating oily water.

Abstract: Several zeolite membrane types, including Mordenite (MOR), Linde Type A (LTA), and Faujasite (FAU), have been developed. Among these membranes, FAU zeolite membranes have a variety of applications, especially in the separation of mixtures that contain large molecules. The goal of this study is to use zeolite membranes (Y/alumina) to separate suspensions of oil-in-water emulsion. Two ceramic supports were prepared from the alumina at different sintering temperatures (700°C and 1200°C) to obtain gamma-alumina and alpha-alumina, respectively. The materials prepared, zeolite Y membranes/alpha-alumina and Y/gamma-alumina, were characterized using X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The powder pressing method was used to compact the alpha-alumina and gamma-alumina ceramic support and the dip-coating method was used to prepare the zeolite Y membranes. The XRD pattern showed that the zeolite Y membrane/alumina obtained by the secondary growth dip-coating method, independent of the ceramic support used, showed no trace of the phases characterized as impurities. It was possible to observe a significant reduction in the concentration of oil in the permeate for the zeolite Y membranes, thus showing their potential for use in this application.

Abstract: The present study describes the preparation of catalyst MoO₃ supported on smectite clay by the solution impregnation method and its evaluation as a heterogeneous catalyst in the production of biodiesel from soybean oil. The individual effects of catalyst (hard green clay and MoO₃/hard green clay) on kinematic viscosity of produced biodiesel and conversion were investigated. The samples were characterized by X-ray diffraction, X-ray fluorescence spectroscopy and N₂ adsorption-desorption. Conditions of soybean oil transesterification were: 5% catalyst by weight, 1:12 oil to methanol molar ratio, at 200 oC for 60 minutes. Patterns of X-ray diffraction showed the characteristic peaks of the structure of smectite. The results of X-ray diffraction suggests that MoO₃ species exist as highly dispersed surface species. Molybdenum metal identified as effective catalysts for the transesterification reaction of soybean oil with methanol. A preliminary design assessment show that this catalysts (MoO₃/HGC) is sufficiently active achieving conversion in excess of 62,07% at temperature below 200 oC.

Abstract: The study aims to evaluate the technical properties of the application of filler element for slab as a hollow ceramic blocks for non-load-bearing masonry. This ceramic product has dimensions of approximately 6.5x25x81.5 cm, and because it presents different geometries of the conventional ceramic block and characteristics different from those required by the norm, this product was submitted to the norms of non-load-bearing masonry and being carried out tests of geometry, water absorption and compressive strength, besides the visual characteristics according to the standard ABNT NBR 15270/2005. Thirteen samples were used for the geometry and compressive strength test, and six for the water absorption test. Some samples presented a great deviation from the square, besides not being within the established limits of the planes and septa. The water absorption is within the established limits and compressive strength is lower than that required by the standard.

Abstract: Several factors can influence the hue variation of tiles through contact elements; the pressure on the surface to be decorated is an important feature. This paper studied this variable applied to decoration by silicone cylinders. A variation of height was made between the cylinder and the tile. The influence of the feature is linked to cylinder wear and distance decrease. The reflectance, as well as the shape and filling of the decorated dots of gray scale values (5, 25 and 85%) were analyzed; the heights studied were 0.8; 1.0; 1.3 and 1.5mm. A similar behavior was observed in the engraving studied; in low shades of gray the reflectance decreases with increasing pressure and then becomes directly proportional; in the middle and high tones range the general trend was an increase in reflectance with increasing pressure on the ceramic tile.

Abstract: This work aims to characterize the post-consumption plaster and compare it with virgin plaster. Burrs from plaster frames manufacturing were collected at the manufacturer. These samples were dried in a drying oven. Then, they were milled in a ball mill, until forming a fine and homogeneous powder. The samples were returned to the drying oven at three different temperatures, 100, 150 and 200°C, to define the best drying temperature, because the water removed in this process changes the structure of the semi-hydrated calcium sulfate gypsum into bihydrated. Then, vibrational Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were performed to characterize the virgin plaster and the reused plaster, making it possible to know the structure and the groups present in the components.