209 resultados para Raw materials ceramic


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The Bi-Sr-Ca-Cu-O system has been one of the most studied superconducting ceramic materials for industry applications. The most of the studies with this aim are on silver/ceramic composites, due to the benefits and great compatibility of this metal with the oxide. Tapes made by the powder in tube (PIT) method have been successfully tested in pilot power plants in many countries but in Brazil. In this paper, 5, 10, and 20-wt% silver powders are introduced to compose the core of the tape along with the Bi:2212 ceramic powder. The results of electrical experiments are compared with those made with no silver addition Ag tapes. The best current density, at 60 K and no applied magnetic field, was found for the 10-wt% silver proportion, doubling the value obtained for the tape with no silver in the core.

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Pós-graduação em Ciência Florestal - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The objective of this work was the analysis of the energetic ethanol production systems using as source of carbohydrates, manioc, sugar cane and maize crops. The searches were carried from the field in the Paranapanema River Valley, state of Sao Paulo in the operations of cultivation and industrial processing of raw materials for analysis. The expenditure of energy concerning the agricultural part was made by the energy consumption of stage production of one hectare of sugar cane, cassava and corn, tillage and planting procedure, inputs, driving the crop, harvest, transport industry and energy draining. The expenditure of energy referring to the part was made by the industry energy consumption of stage processing of one tonne of sugar cane, cassava and corn, in the operations of disintegration / milling, hydrolysis / treatment of the broth, fermentation, distillation and maintenance of equipment. Under the system of agronomic production of raw materials, manioc presented an energy expenditure below that of sugar cane and maize (9,528.33 MJ ha-1; 14,370.90 MJ ha-1 and 15,633.83 MJ ha-1, respectively). For the ethanol produced, the operations of cultivation has consumed 1.54 MJ l-1 with manioc; MJ 1.99 l-1 with sugar cane, and 7.9 MJ l-1 with the corn. In the industrial processing of a ton of raw material, sugar cane presented an energy cost less than the cassava and maize (1,641.56 MJ t-1; 2,208.28 MJ t-1 and MJ 3,882.39 t-1, Respectively), however, showed a higher cost than when they related to ethanol produced (19.38 MJ l-1; 11.76 MJ l-1 and 11.76 MJ l-1, respectively). In the final energy balance for each megajoules of energy invested in sugar cane were required 1.09 MJ (9%), for each megajoules of energy invested in manioc were required 1.76 MJ (76%) and for each megajoules energy invested in maize were required 1.19 MJ (19%). Overall, it appears that the manioc consumes less energy than sugar cane and corn crops in the process of agribusiness obtaining ethanol.

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Aiming to get the best economic advantage in ethanol production from cassava roots, this study presented a physiochemical characterization from two different types of solid waste in two types of processing of the raw materials in manufacturing ethanol. The processing of cassava roots begins with the disintegration and washing the roots with the addition of 20% more water to obtain a pulp which was treated and stirred in the reactor while adding enzyme α-amylase at a temperature of 90°C for 2 hours. Then we performed a pH adjustment while lowering the temperature to 60 ° C with the addition of the enzyme amiloglucosidase and then stirring for 14 hours. The hydrolyzate obtained was the source of two types of waste which are: i) Solid residue obtained after filtration of the hydrolyatze and ii) Solid waste obtained from filtering wine after alcoholic fermentation of the hydrolyzate with the addition of a dried yeast strain Y-940 manufactured by MAURI OF BRAZIL SA (2%) at a temperature of 25º C. The results of the laboratory analysis showed that the byproducts derived from the hydrolysis and fermentation showed very similar chemical compositions. With levels between 39 and 41% fiber, 0.5% lipids, 20 and 30% carbohydrates, protein 0.5 and 1.50, 6 and 8% acidity, and 20 and 30% soluble solids.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The bamboo waste can be an alternative material to sustain the crescent demand for particleboards, also bringing ecological benefits as reduction of the pressure for raw materials and landfill space demands. In this context, this research aimed to manufacture and determine some physical and mechanical properties of particleboards with bamboo waste particles (Dendrocalamus giganteus), obtained from different sources, bonded with four different percentages of urea–formaldehyde (UF) based resin (6%, 8%, 10% and 12% related to dry material of particles). Response variables investigated were: density; moisture content; thickness swelling in 2 and 24 hours; water absorption in 2 and 24 hours; internal adhesion (STpe); strength in tension parallel to faces (STpa); modulus of elasticity (MOE) and modulus of rupture (MOR). Results permitted to conclude that particleboards as mentioned showed good performance only in the physical properties requirements imposed by Brazilian Standard NBR 14810, but this was not observed to mechanical properties considered. New researches are needed in order to optimize the producing process parameters.

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The problem of proper disposal of solid waste generated in different industrial processes is one of worldwide environmental concerns nowadays. Thus, this study aimed to establish a new alternative for the disposal of two agro-industrial residues employing them to produce particleboard for different purposes in building construction. The focus was given to the reuse of the sugarcane bagasse (SB) originated during the processing of Saccharum officinarum for sugar and ethanol production, and bamboo stem leaves of Dendrocalamus giganteus(BB). For this, six particleboards were produced in the following compositions: with 100% SB, 75% SB + 25% BB, 50% SB+50% BB, 40% SB +60 BB, 25% SB+ 75% BB and 100% BB in the total mass of the composites. The particleboards physical characterization followed Brazilian Standard ABNT NBR 14810-3 to density, moisture content and water absorption. Results showed these raw materials are compatible to particleboard production.

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In this research the aim was produce a particleboard with alternative materials and evaluated its physical and mechanical characteristics. The raw materials used are residues from sucarcane bagasse (SC) (Saccharum officinarum) and stem leaves of bamboo (B) (Dendrocalamus giganteus), bonded with a bi component adhesive based on castor oil. It was produced particleboards with five different traces: 100% SC, 75% SC+25% B, 50% SC+50% B, 25% SC +75%B and 100 % B. Their physical and mechanical characteristics were evaluated accordingly to Brazilian standard NBR 14810-3. Regarding the results obtained, it can be detached that for physical and mechanical evaluation it is evident a negative relation among the amount the sugarcane bagasse and their physical and mechanical characteristics, that is particleboards with low concentrations of sugarcane bagasse had better results. However all particleboards could be recommended for use as sealing particleboards in the segment of civil construction.

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In recent years the production of products derived from wood and bamboo are increasing, due to the search for a more rational exploitation of these raw materials. Amongst these products, the particleboards production combine sustainability and rationality in the use of these materials. In this context, this work has the objective to study the application of alternative raw materials in the manufacture of Medium Density Particleboards (MDP), using residues from industrial processimg of coffee and bamboo. MDP had been produced with particles of giganteus bamboo of the Dendrocalamus species and particle of coffee rind in the intermediate layer of the particleboard, bonded with polyurethane resin based on castor oil. The physical and mechanical characterization was carried out accordingly to NBR 14810-3 (2006). The physical properties evaluated were: of water absorption for 2h and 24h; thickness swallowing for 2h and 24h; density, humidity content. The mechanical properties evaluated were: Tensile strength, static bending (MOR and MOE). The results were compared with NBR 14810-2 (2006) and also with the ANSI A208-1 (1993). The physical performance of these particleboards was below the values recommend by the Brazilian norm. Also the mechanical characteristics are not improve, demonstrating that the inclusion of coffee rind did not benefit the physical characteristics and nor the mechanical ones. However it can be used as construction materials for partitions and ceiling panels.