936 resultados para W280 Interactive and Electronic Design
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Global society and technology have changed the relationships of the market. Quality and cost are not the main aspects of any industrial product. On the other hand, design, innovation and sustainability became significant requirements to company’s competitiveness. In this context, the design approach has shown evolutions, integrating social and environmental aspects beside traditional aspects such as technical and economic. Still, design has been becoming a strategic opportunity for companies, improving their competitiveness and increasing their market share. Thus, this research has analyzed the integration of both the Sustainable Design and Strategic Design Coaching (SDC) method in the making decision activities of companies. A cement company (BQMIL) was assigned as case study, in which the previous results have pointed out the significant hole of those concepts to generate Eco-innovation and Eco-Brand to increase its market share, corroborating the expectative of the design team
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Purpose:The purpose of this study was to evaluate stress transfer patterns between implant-tooth-connected prostheses comparing rigid and semirigid connectors and internal and external hexagon implants.Materials and Methods:Two models were made of photoelastic resin PL-2, with an internal hexagon implant of 4.00 x 13 mm and another with an external hexagon implant of 4.00 x 13 mm. Three denture designs were fabricated for each implant model, incorporating one type of connection in each one to connect implants and teeth: 1) welded rigid connection; 2) semirigid connection; and 3) rigid connection with occlusal screw. The models were placed in the polariscope, and 100-N axial forces were applied on fixed points on the occlusal surface of the dentures.Results:There was a trend toward less intensity in the stresses on the semirigid connection and solid rigid connection in the model with the external hexagon; among the three types of connections in the model with the internal hexagon implant, the semirigid connection was the most unfavorable one; in the tooth-implant association, it is preferable to use the external hexagon implant.Conclusions:The internal hexagon implant establishes a greater depth of hexagon retention and an increase in the level of denture stability in comparison with the implant with the external hexagon. However, this greater stability of the internal hexagon generated greater stresses in the abutment structures. Therefore, when this association is necessary, it is preferable to use the external hexagon implant.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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We describe a new physicochemical descriptor of the antioxidant activity of phenols, the energy difference between the two highest occupied molecular orbitals, which we believe will improve quantitative structure-activity relationship studies about these compounds. (C) 2003 Wiley Periodicals, Inc.
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The relation between the composition and electronic structure of the perfectly inverse spinel compound Zn7-xMxSb2O12 (M = Ni and Co) has been studied by powder X-ray diffraction and X-ray photoelectron spectroscopy. Changes in the site occupancy are associated with shifts in the core levels as observed in the core level spectral analyses. The configuration of the density of states in the valence band due to the Co and Ni states can be observed in the valence band spectra. (C) 2004 Elsevier B.V. All rights reserved.
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Structural and electronic properties of the bulk and relaxed surfaces (TiO2 and PbO terminated) of cubic PbTiO3 are investigated by means of periodic quantum-mechanical calculations based on density functional theory. It is observed that the difference in surface energies is small and relaxations effects are most prominent for Ti and Ph surface atoms. The electronic structure shows a splitting of the lowest conduction bands for the TiO2 terminated surface and of the highest valence bands for the PbO terminated slab. The calculated indirect band gap is: 3.18, 2.99 and 3.03 eV for bulk, TiO2 and PbO terminations, respectively. The electron density maps show that the Ti-O bond has a partial covalent character, whereas the Pb-O bonds present a very low covalency. (C) 2004 Elsevier B.V. All rights reserved.
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The present study is concerned with the structural and electronic properties of the TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 composite systems. Periodic quantum mechanical method with density functional theory at the B3LYP level has been carried out. Relaxed surface energies, structural characteristics and electronic properties of the (I 10), (0 10), (10 1) and (00) low-index rutile surfaces for TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 models are studied. For, comparison purposes, the bare rutile TiO2 and SnO2 structures are also analyzed and compared with previous theoretical and experimental data. The calculated surface energy for both rutile TiO2 and SnO2 surfaces follows the sequence (110) < (010) < (101) < (001) and the energy increases as (010) < (101) < (110) < (001) and (010) approximate to (110) < (101) < (001) for SnO2/TiO2/SnO2 and TiO2/SnO2/TiO2 composite systems, respectively. SnO2/TiO2/SnO2 presents larger values of surface energy than the individual SnO2 and TiO2 metal oxides and the TiO2/SnO2/TiO2 system renders surface energy values of the same order that the TiO2 and lower than the SnO2. An analysis of the electronic structure of the TiO2/SnO2/TiO2 and SnO2/TiO2/SnO2 systems shows that the main characteristics of the upper part of the valence bands for all the studied surfaces are dominated by the external layers, i.e., by the TiO2 and the SnO2, respectively, and the topology of the lower part of the conduction bands looks like the core layers. There is an energy stabilization of both valence band top and conduction band bottom for (110) and (010) surfaces of the SnO2/TiO2/SnO2 composite system in relation to their core TiO2, whereas an opposite trend is found for the same surfaces of the TiO2/SnO2/TiO2 composite system in relation to the bare SnO2. The present theoretical results may explain the growth of TiO2@SnO2 bimorph composite nanotape.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The preparation and characterization of (Ph3AsOH)2[CuBr4] and [Cu(Ph3AsO)4][CuBr4] are reported (Ph3AsO = triphenylarsine oxide). Crystallographic analysis of the monoclinic crystals of (Ph3AsOH)2[CuBr4] (space group C2/c, a = 17.569 (3) Å, b = 13.090 (2) Å, c = 16.933 (2) Å, and β = 105.64 (2)°, R = 0.055 and Rw = 0.057) revealed the presence of compressed [CuBr4]2- tetrahedra of C2 symmetry with Cu-Br distances of 2.340 (1) and 2.437 (1) Å and trans-Br-Cu-Br angles of 139.2 (1) and 122.4 (1)°. The oxonium cations hydrogen bond to the bromine atoms involved in the longer Cu-Br bonds and the smaller trans-Br-Cu-Br angle. Single-crystal electronic and EPR spectra are interpreted in terms of the observed [CuBr4]2- geometry. Analysis of the electronic and EPR spectra of [Cu(Ph3AsO)4][CuBr4] led to the postulation of the presence of planar [Cu(Ph3AsO)4]2+ cations and distorted tetrahedral [CuBr4]2- anions. © 1992 American Chemical Society.
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The crystal and molecular structures of the following molecules have been determined: 1-acetyl-indoline, 1-acetyl-5-nitro-indoline, 1-acetyl-5-nitro-7-bromo-indoline, 1-acetyl-5-bromo-7-nitro-indoline, and 1-acetyl-5-bromo-7-nitro-indol. Molecular orbital calculations are performed for these compounds and two related species.
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We investigate the effect that the temperature dependence of the crystal structure of a two-dimensional organic charge-transfer salt has on the low-energy Hamiltonian representation of the electronic structure. For that, we determine the crystal structure of κ-(BEDT-TTF) 2Cu 2(CN) 3 for a series of temperatures between T=5 and 300 K by single crystal X-ray diffraction and analyze the evolution of the electronic structure with temperature by using density functional theory and tight binding methods. We find a considerable temperature dependence of the corresponding triangular lattice Hubbard Hamiltonian parameters. We conclude that even in the absence of a change of symmetry, the temperature dependence of quantities like frustration and interaction strength can be significant and should be taken into account. © 2012 American Physical Society.
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Includes bibliography