983 resultados para micro-mesh gaseous structure


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A series of activated carbons were prepared by carbonization of polyaniline at different temperatures, using KOH or K2CO3 as activating agent. Pure microporous or micro/mesoporous activated carbons were obtained depending on the preparation conditions. Carbonization temperature has been proven to be a key parameter to define the textural properties of the carbon when using KOH. Low carbonization temperatures (400–650 °C) yield materials with a highly developed micro- and mesoporous structure, whereas high temperatures (800 °C) yield microporous carbons. Some of the materials prepared using KOH exhibit a BET surface area superior to 4000 m2/g, with total pore volume exceeding 2.5 cm3/g, which are among the largest found for activated carbons. On the other hand, microporous materials are obtained when using K2CO3, independently of carbonization temperature. Some of the materials were tested for CO2 capture due to their high microporosity and N content. The adsorption capacity for CO2 at atmospheric pressure and 0 °C achieves a value of ∼7.6 mmol CO2/g, which is among the largest reported in the literature. This study provides guidelines for the design of activated carbons with a proper N/C ratio for CO2 capture at atmospheric pressure.

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In the process of engineering design of structural shapes, the flat plate analysis results can be generalized to predict behaviors of complete structural shapes. In this case, the purpose of this project is to analyze a thin flat plate under conductive heat transfer and to simulate the temperature distribution, thermal stresses, total displacements, and buckling deformations. The current approach in these cases has been using the Finite Element Method (FEM), whose basis is the construction of a conforming mesh. In contrast, this project uses the mesh-free Scan Solve Method. This method eliminates the meshing limitation using a non-conforming mesh. I implemented this modeling process developing numerical algorithms and software tools to model thermally induced buckling. In addition, convergence analysis was achieved, and the results were compared with FEM. In conclusion, the results demonstrate that the method gives similar solutions to FEM in quality, but it is computationally less time consuming.

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Fats and oils are very important raw materials and functional ingredients for several food products such as confectionery, bakery, ice creams, emulsions, and sauces, shortenings, margarines, and other specially tailored products. Formulated products are made with just about every part of chemistry, but they are not simple chemicals. In general, they consist of several, and often many, components. Each of these components has a purpose. Most formulated products have a micro- or nano-structure that is important for their function, but obtaining this structure is often the big challenge. Due to a rise in overweight or obesity, health concerns have increased. This fact has led to the need to the develop products with low fat content, which have become a market trend. In addition, the development of new products using fat substitutes can be a good option for companies that are always trying to reduce costs or substitute trans fat or saturated fat. However, the successful development of these products is still a challenge because fat plays multiple roles in determining the desirable physicochemical and sensory attributes, and because the consumers who want or need to replace these ingredients, seek products with similar characteristics to those of the original product. Important attributes such as smooth, creamy and rich texture; milky and creamy appearance; desirable flavor; and satiating effects are influenced by the droplets of fat, and these characteristics are paramount to the consumer and consequently crucial to the success of the product in the market. Therefore, it is important to identify commercially viable strategies that are capable of removing or reducing fat content of food products without altering their sensory and nutritional characteristics. This paper intended to provide an overview about the role of fat in different food systems such as chocolate, ice cream, bakery products like biscuits, breads, and cakes considering the major trends of the food industry to meet the demands of modern society.

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A prestação jurisdicional eficiente e eficaz é uma exigência social e constitucional. Um círculo virtuoso pode ser instaurado pela cobrança social de melhoria dos serviços prestados pelo Poder Judiciário. A resposta a essa exigência é necessária, com a reformulação e revisão de conceitos, estruturas e cultura organizacional. A atuação nessa seara impacta a legitimação do Poder Judiciário, podendo elevá-la tanto mais satisfeitas as expectativas sociais. Os conceitos de gestão e sua implementação devem ser parte das atividades judiciais, desde a alta administração até a gestão da unidade judicial. Há necessidade, portanto, de um sistema de gestão que permeie todas as atividades desenvolvidas. O Tribunal de Justiça do Rio Grande do Sul desde 1995 adotou o Programa Gaúcho de Qualidade e Produtividade (PGQP), através do Plano de Gestão pela Qualidade no Poder Judiciário do Rio Grande do Sul (PGQJ). A recente formulação do Planejamento Estratégico trouxe novas perspectivas, objetivos e desafios. A concreção dos objetivos estratégicos traçados depende do alinhamento das unidades judiciais. Surge aí a importância de um sistema de gestão das unidades judiciais, com elementos e indicadores definidos, permitindo a visualização pela alta administração do andamento da instituição em busca dos objetivos estabelecidos. Alinhada à importância do tema, propõe-se a apresentação dos principais elementos formadores de um sistema de gestão de unidade judicial: direcionamento e alinhamento estratégico; planejamento da microgestão; estrutura organizacional; processos de trabalho; procedimentos operacionais padrão; rotinas cartorárias; gestão de pessoas; treinamento e liderança. O Sistema de Gerenciamento Matricial dos Serviços Judiciários (GMS- JUD), desenvolvido pelo Tribunal de Justiça do Rio Grande do Sul com a consultoria do Instituto Nacional de Desenvolvimento Gerencial (INDG), é apresentado como direcionador de acompanhamento do planejamento traçado pelas unidades judiciais, compondo o sistema de gestão proposto.

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Crianças e adolescentes necessitam de proteção integral e prioridade na implementação de seus direitos fundamentais individuais. A demora na tramitação dos processos judiciais constitui um grave problema da Justiça. A eficiência do Poder Judiciário em distribuir justiça está condicionada à prestação jurisdicional rápida, à efetividade do processo. As transformações sociais, econômicas, tecnológicas têm operado muitas mudanças na rotina dos Tribunais. Uma delas é a implantação do sistema de gestão da qualidade nas serventias judiciais. A qualidade da prestação jurisdicional dependerá da gestão imprimida pelo juiz na sua unidade. Diante disso, o presente trabalho destina-se a apresentar uma proposta de sistema de gestão no âmbito da Vara da Infância e Juventude de Porto Velho, Estado de Rondônia, dividido em catorze etapas: foco da organização, direcionadores estratégicos, planejamento da gestão, estrutura organizacional, comunicação, gestão de pessoas, infraestrutura, processos de trabalho, documentos e normas, registros, medição, tratamento de falhas, análise crítica e avaliação dos resultados.

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In this work a computational method is presented to simulate the movements of vocal folds in three dimensions. The proposed model consists of a mesh free structure where each vertex is connected its neighbor through a group spring-damper. Forced oscillations were studied by time varying surface forces. The preliminary results using this model are similar with the literature and with the experimental stroboscopic observations of larynx. © 2006 IEEE.

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The interest in automatic volume meshing for finite element analysis (FEA) has grown more since the appearance of microfocus CT (μCT), due to its high resolution, which allows for the assessment of mechanical behaviour at a high precision. Nevertheless, the basic meshing approach of generating one hexahedron per voxel produces jagged edges. To prevent this effect, smoothing algorithms have been introduced to enhance the topology of the mesh. However, whether smoothing also improves the accuracy of voxel-based meshes in clinical applications is still under question. There is a trade-off between smoothing and quality of elements in the mesh. Distorted elements may be produced by excessive smoothing and reduce accuracy of the mesh. In the present work, influence of smoothing on the accuracy of voxel-based meshes in micro-FE was assessed. An accurate 3D model of a trabecular structure with known apparent mechanical properties was used as a reference model. Virtual CT scans of this reference model (with resolutions of 16, 32 and 64 μm) were then created and used to build voxel-based meshes of the microarchitecture. Effects of smoothing on the apparent mechanical properties of the voxel-based meshes as compared to the reference model were evaluated. Apparent Young’s moduli of the smooth voxel-based mesh were significantly closer to those of the reference model for the 16 and 32 μm resolutions. Improvements were not significant for the 64 μm, due to loss of trabecular connectivity in the model. This study shows that smoothing offers a real benefit to voxel-based meshes used in micro-FE. It might also broaden voxel-based meshing to other biomechanical domains where it was not used previously due to lack of accuracy. As an example, this work will be used in the framework of the European project ContraCancrum, which aims at providing a patient-specific simulation of tumour development in brain and lungs for oncologists. For this type of clinical application, such a fast, automatic, and accurate generation of the mesh is of great benefit.

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This paper presents the assessment of the out-of-plane response due to seismic loading of a masonry structure without rigid diaphragm. This structure corresponds to real scale brick masonry specimen with a main façade connected to two return walls. Two modelling approaches were defined for this evaluation. The first one consisted on macro modelling, whereas the second one on simplified micro modelling. As a first step of this study, static nonlinear analyses were conducted to the macro model aiming at evaluating the out-of-plane response and failure mechanism of the masonry structure. A sensibility analyses was performed in order to assess the mesh size and material model dependency. In addition, the macro models were subjected to dynamic nonlinear analyses with time integration in order to assess the collapse mechanism. Finally, these analyses were also applied to a simplified micro model of the masonry structure. Furthermore, these results were compared to experimental response from shaking table tests. It was observed that these numerical techniques simulate correctly the in-plane behaviour of masonry structures. However, the

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Aims: In a head-to-head study, we compared the effects of strontium ranelate (SrRan) and alendronate (ALN), anti-osteoporotic agents with antifracture efficacy, on bone microstructure, a component of bone quality, hence of bone strength. Methods: In a randomised, double-dummy, double-blind controlled trial, 88 postmenopausal osteoporotic women were randomised to SrRan 2g/day or ALN 70mg/week for 2 years. Microstructure of the distal radius and distal tibia were assessed by HR-pQCT after 3,6,12,18 and 24 months of treatment. Primary endpoint was HR-pQCT variables relative changes from baseline. An ITT analysis was applied. Results: Baseline characteristics were similar in both groups (mean ±SD): age: 63.6±7.5 vs. 63.7±7.6 yrs; L1-L4T Score: -2.7±0.8 vs. -2.8±0.8g/cm², Cortical Thickness (CTh), trabecular bone fraction (BV/TV) and cortical density=721±242 vs. 753±263μm, 9.5±2.5 vs. 9.3±2.7%, and 750±87 vs. 745±78mg/cm3 respectively. Over 2 yrs, distal radius values changes were within 1 to 2% without significant differences except cortical density. In contrast distal tibia CTh, BV/TV, trabecular and cortical densities increased significantly more in the SrRan group than in the ALN group (Table). No significant between-group differences were observed for the remaining measured parameter (trabecular number, trabecular spacing, and trabecular thickness). After 2 years, L1- L4 and hip aBMD increases were similar to results from pivotal trials (L1-L4:+6.5% and +5.6%;total hip:+4.1% and +2.9%, in Sr- Ran and ALN groups, respectively). In the SrRan group, bALP increased by a median of 18% (p<0.001) and sCTX decreased by a median of -16% (p=0.005) while in the ALN group, bALP and CTX decreased by median of -31% (p<0.001) and -59% (p<0.001) respectively. Relative changes from baseline to last observation (%) SrRan ALN Estimated between group difference p value CTh (μm) 6.29±9.53 0.93±6.23 5.411±1.836 0.004 BV/TV (%) 2.48±5.13 0.84±3.81 1.783±0.852 0.040 Trabecular density (mgHA/cm3) 2.47±5.07 0.88±4.00 1.729±0.859 0.048 Cortical density (mgHA/cm3) 1.43±2.77 0.36±2.14 1.137±0.530 0.045 The two treatments were well tolerated. Conclusions: Within the constraints related to HRpQCT technology, it appears that strontium ranelate has greater effects than alendronate on distal tibia cortical thickness, trabecular and cortical bone densities in women with postmenopausal osteoporosis after two years of treatment. A concomitant significant increase in bone formation marker is observed in the SrRan group.

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The saphenous vein is the conduit of choice in bypass graft procedures. Haemodynamic factors play a major role in the development of intimal hyperplasia (IH), and subsequent bypass failure. To evaluate the potential protective effect of external reinforcement on such a failure, we developed an ex vivo model for the perfusion of segments of human saphenous veins under arterial shear stress. In veins submitted to pulsatile high pressure (mean pressure at 100 mmHg) for 3 or 7 days, the use of an external macroporous polyester mesh 1) prevented the dilatation of the vessel, 2) decreased the development of IH, 3) reduced the apoptosis of smooth muscle cells, and the subsequent fibrosis of the media layer, 4) prevented the remodelling of extracellular matrix through the up-regulation of matrix metalloproteinases (MMP-2, MMP-9) and plasminogen activator type I. The data show that, in an experimental ex vivo setting, an external scaffold decreases IH and maintains the integrity of veins exposed to arterial pressure, via increase in shear stress and decrease wall tension, that likely contribute to trigger selective molecular and cellular changes.

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Gallaborane (GaBH6, 1), synthesized by the metathesis of LiBH4 with [H2GaCl]n at ca. 250 K, has been characterized by chemical analysis and by its IR and 1H and 11B NMR spectra. The IR spectrum of the vapor at low pressure implies the presence of only one species, viz. H2Ga(μ-H)2BH2, with a diborane-like structure conforming to C2v symmetry. The structure of this molecule has been determined by gas-phase electron diffraction (GED) measurements afforced by the results of ab initio molecular orbital calculations. Hence the principal distances (rα in Å) and angles ( α in deg) are as follows: r(Ga•••B), 2.197(3); r(Ga−Ht), 1.555(6); r(Ga−Hb), 1.800(6); r(B−Ht), 1.189(7); r(B−Hb), 1.286(7); Hb−Ga−Hb, 71.6(4); and Hb−B−Hb, 110.0(5) (t = terminal, b = bridging). Aggregation of the molecules occurs in the condensed phases. X-ray crystallographic studies of a single crystal at 110 K reveal a polymeric network with helical chains made up of alternating pseudotetrahedral GaH4 and BH4 units linked through single hydrogen bridges; the average Ga•••B distance is now 2.473(7) Å. The compound decomposes in the condensed phases at temperatures exceeding ca. 240 K with the formation of elemental Ga and H2 and B2H6. The reactions with NH3, Me3N, and Me3P are also described.

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The objective of this study is to describe the design and the implementation of an experimental set-up used to study the dynamics, the experimental identification, and the active vibration control of a flexible structure mounted manipulator system. The system consists of a three-degree-of-freedom cylindrical manipulator system with a flexible link on its tip. A two-degree-of-freedom polar rigid manipulator is mounted on the flexible macromanipulator. The dynamic modelling and experimental modal analysis identification in the frequency domain are being applied to design active digital control strategies for the micro-manipulator system to damp the mechanical vibrations of the flexible structure on the tip of the macro-manipulator system.

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A scheme is presented in which an organic solvent environment in combination with surfactants is used to confine a natively unfolded protein inside an inverse microemulsion droplet. This type of confinement allows a study that provides unique insight into the dynamic structure of an unfolded, flexible protein which is still solvated and thus under near-physiological conditions. In a model system, the protein osteopontin (OPN) is used. It is a highly phosphorylated glycoprotein that is expressed in a wide range of cells and tissues for which limited structural analysis exists due to the high degree of flexibility and large number of post-translational modifications. OPN is implicated in tissue functions, such as inflammation and mineralisation. It also has a key function in tumour metastasis and progression. Circular dichroism measurements show that confinement enhances the secondary structural features of the protein. Small-angle X-ray scattering and dynamic light scattering show that OPN changes from being a flexible protein in aqueous solution to adopting a less flexible and more compact structure inside the microemulsion droplets. This novel approach for confining proteins while they are still hydrated may aid in studying the structure of a wide range of natively unfolded proteins.

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This technical report discusses the application of Lattice Boltzmann Method (LBM) in the fluid flow simulation through porous filter-wall of disordered media. The diesel particulate filter (DPF) is an example of disordered media. DPF is developed as a cutting edge technology to reduce harmful particulate matter in the engine exhaust. Porous filter-wall of DPF traps these soot particles in the after-treatment of the exhaust gas. To examine the phenomena inside the DPF, researchers are looking forward to use the Lattice Boltzmann Method as a promising alternative simulation tool. The lattice Boltzmann method is comparatively a newer numerical scheme and can be used to simulate fluid flow for single-component single-phase, single-component multi-phase. It is also an excellent method for modelling flow through disordered media. The current work focuses on a single-phase fluid flow simulation inside the porous micro-structure using LBM. Firstly, the theory concerning the development of LBM is discussed. LBM evolution is always related to Lattice gas Cellular Automata (LGCA), but it is also shown that this method is a special discretized form of the continuous Boltzmann equation. Since all the simulations are conducted in two-dimensions, the equations developed are in reference with D2Q9 (two-dimensional 9-velocity) model. The artificially created porous micro-structure is used in this study. The flow simulations are conducted by considering air and CO2 gas as fluids. The numerical model used in this study is explained with a flowchart and the coding steps. The numerical code is constructed in MATLAB. Different types of boundary conditions and their importance is discussed separately. Also the equations specific to boundary conditions are derived. The pressure and velocity contours over the porous domain are studied and recorded. The results are compared with the published work. The permeability values obtained in this study can be fitted to the relation proposed by Nabovati [8], and the results are in excellent agreement within porosity range of 0.4 to 0.8.