792 resultados para Painel
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When a company desires to invest in a project, it must obtain resources needed to make the investment. The alternatives are using firm s internal resources or obtain external resources through contracts of debt and issuance of shares. Decisions involving the composition of internal resources, debt and shares in the total resources used to finance the activities of a company related to the choice of its capital structure. Although there are studies in the area of finance on the debt determinants of firms, the issue of capital structure is still controversial. This work sought to identify the predominant factors that determine the capital structure of Brazilian share capital, non-financial firms. This work was used a quantitative approach, with application of the statistical technique of multiple linear regression on data in panel. Estimates were made by the method of ordinary least squares with model of fixed effects. About 116 companies were selected to participate in this research. The period considered is from 2003 to 2007. The variables and hypotheses tested in this study were built based on theories of capital structure and in empirical researches. Results indicate that the variables, such as risk, size, and composition of assets and firms growth influence their indebtedness. The profitability variable was not relevant to the composition of indebtedness of the companies analyzed. However, analyzing only the long-term debt, comes to the conclusion that the relevant variables are the size of firms and, especially, the composition of its assets (tangibility).This sense, the smaller the size of the undertaking or the greater the representation of fixed assets in total assets, the greater its propensity to long-term debt. Furthermore, this research could not identify a predominant theory to explain the capital structure of Brazilian
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Low voltage solar panels increase the reliability of solar panels due to reduction of in series associations the configurations of photovoltaic cells. The low voltage generation requires DCDC converters devices with high efficiency, enabling raise and regulate the output voltage. This study analyzes the performance of a photovoltaic panel of Solarex, MSX model 77, configured to generate an open circuit voltage of 10.5 V, with load voltage of 8.5 V, with short circuit current of 9 A and a power of 77 W. The solar panel was assembled in the isolated photovoltaic system configuration, with and without energy storage as an interface with a DCDC converter, Booster topology. The converter was designed and fabricated using SMD (Surface Mounted Devices) technology IC (integrated circuit) that regulates its output voltage at 14.2 V, with an efficiency of 87% and providing the load a maximum power of 20.88 W. The system was installed and instrumented for measurement and acquisition of the following data: luminosities, average global radiation (data of INPE Instituto Nacional de Pesquisas Espaciais), solar panel and environment temperatures, solar panel and DC-DC converter output voltages, panel, inverter, and battery charge output currents. The photovoltaic system was initially tested in the laboratory (simulating its functioning in ideal conditions of operation) and then subjected to testing in real field conditions. The panel inclination angle was set at 5.5°, consistent with the latitude of Natal city. Factors such as climatic conditions (simultaneous variations of temperature, solar luminosities and ra diation on the panel), values of load resistance, lower limit of the maximum power required by the load (20.88 W) were predominant factors that panel does not operate with energy efficiency levels greater than 5 to 6%. The average converter efficiency designed in the field test reached 95%
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em História - FCHS
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Products derived from wood or engineered products are becoming interesting alternatives to the replacement of solid wood in various applications, from structural components to the furniture industry and packaging. Among these products, there are panels built by strands, particles and fibers, each one having their particular characteristics and potential of use. Since the different types of panels are produced, waste generation is part of the process, and that more technological it is, it still generates losses of raw materials. Based on the need for rational use of raw materials and using almost full of industrially processed wood, It arises the proposal of this work, which seeks to use waste from the lamination, like pieces of strands, broken strands, strands rough, cracked strands to produce panels with structural characteristics of the OSL panel (Oriented Strand Lumber), LSL (Laminated Strand Lumber) and OSB (Oriented Strand Lumber). Besides the use of waste, this paper seeks an alternative to the use of the adhesive, because the industry uses formaldehyde-based adhesives, which over the press, they emit large amounts of formaldehyde, which is very aggressive to humans and environment. The panels made with polyurethane resin based on castor oil and hot-pressed were characterized by physical and mechanical tests according to specifications of European Standard (EN). High values of tensile strength, elastic modulus and density were found in the results of tests. Adding to stable values of swelling and moisture content, the panel studied adds attractive features to the panel market, especially in the civil construction
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This work was developed to evalute the physical and mechanical properties of a panel of three particle layers from the test specification of NBR 14810-3 (2006), using wood of Eucalyptus sp. and Eucalyptus saligna and Eucalyptus urograndis bark. The mechanical properties were evaluated to obtain the bending modulus of rupture (MOR) and modulus of elasticity (MOE) and Internal bond. The physical properties were obtained thickness sweeling, water absorption, moisture content and board density. Were evaluated four different compositions of panels containing 5, 10, 15 and 20% in the inner layer of bark. The results were compared with the Brazilian standard NBR 14810-2 (2006) and also with studies in the literature. The panels produced were adequate to all the optimal values suggested by the standard only in the composition with 5% skin in the inner layer. The other treatments showed satisfactory results in all tests except for moisture content
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This work is the production of particleboard of particles reconstituted from MDP (Medium Density Particleboard) adding particles in the inner layer of Mimosa Scarelli, popularly known as bracatinga, the ratios of 0%, 25%, 50%, 75% and 100%. The panel produced is composed of three layers, two external particles with smaller particle size and an inner layer composed of particles of larger particle sizes. Assays were performed based on physical and mechanical NBR 14.810/2006 for the determination of the board density, thickness swelling, water absorption, moisture content, bending strength, shear strength and residual moisture, and testing of particle size not existing in the standard cited. The results were analyzed and compared the results of the commercial boards made from 100% eucalyptus, based on the limits specified by the ABNT NBR 14.810/2006. The values of the tests were close to the normative specifications indicating positively the production of MDP with wood decay.
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Studies on new adhesives and resins for bonding wood and wood products are being conducted with the intention of improving their properties, taking into account a lower environmental impact. For this reason new formulations of polyvinyl acetate (PVA) adhesives have been developed, because they have no chemicals in its composition extremely polluting and harmful to health, as is the case of formaldehyde-based resins, which in turn are the most commonly used today for wood panels production. This study tested three different formulations of PVA adhesives, with different times and temperatures of pressing for the production of Eucalyptus sp. Plywood, coming up in satisfactory results with respect to shear strength at the bondline, which was higher for the PVA adhesives compared with urea-formaldehyde and phenol. The results of MOE and MOR were lower than those values of the panels produced with urea and phenol-formaldehyde, and the results of physical tests showed to be close to the panels produced with these same adhesives
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The manufacture of plywood panel already has about eighty years in Brazil. In general, plywood panels differ by their nature, composition and manufacturing; the most common MDF, OSB, particle and the joist. Some of these products can be generated fromindustrial waste, as the panelblockboard, you can use in their training waste destop boards (Battens), from industrial processes or processing of primary wood. This work aims to present the detailed study of the economic viability of utilization of industrial solid waste timber through the acquisition of a machine amarradeira of joists in a wood processing unit in city Itapeva-SP. We studied the application of wastein the composition of kernels blockboard panel tied its commercial acceptance and future prospects market. We noticed great economic advantage in investing in the study, compared with the transformation process of the joists in biomass energy, although the investment decision involves not only financial matters but also the acceptance market the product to be manufactured
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The research aimed to produce sheets of particles with waste processing of Eucalyptus sp bonded with urea-formaldehyde and evaluate the effect of pressure variation in the quality of the boards produced. To do so, the Boards made were divided into two treatments depending on the pressing pressure of 30 to 40 kgf / cm². Once pressings, climatized, the particleboards have been sectioned in test samples, and underwent physical-mechanical tests for determining density, swelling and water absorption, modulus of rupture and elasticity in static bending and internal linking. The particleboards pressed at 40 kgf / cm ² showed the best results