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| Registros recuperados: 48 | |
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| Guerin, Thomas; Bertin, Xavier; Dodet, Guillaume. |
| Over the last decade, modelling systems based on unstructured grids have been appearing increasingly attractive to investigate the dynamics of coastal zones. However, the resolution of the sediment continuity equation to simulate bed evolution is a complex problem which often leads to the development of numerical oscillations. To overcome this problem, addition of artificial diffusion or bathymetric filters are commonly employed methods, although these techniques can potentially over-smooth the bathymetry. This study aims to present a numerical scheme based on the Weighted Essentially Non-Oscillatory (WENO) formalism to solve the bed continuity equation on unstructured grids in a finite volume formulation. The new solution is compared against a classical... |
| Tipo: Text |
Palavras-chave: Morphodynamic modelling; Unstructured grid; WENO; Diffusion; Coastal environments; Exner equation. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00606/71851/70480.gif |
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| Mycek, Paul; Pinon, Gregory; Germain, Gregory; Rivoalen, Elie. |
| The modelling of diffusive terms in particle methods is a delicate matter and several models have been proposed in the literature. The Diffusion Velocity Method (DVM) consists in rewriting these terms in an advective way, thus defining a so-called diffusion velocity. In addition to the actual velocity, it is used to compute the particles displacement. On the other hand, the well-known and commonly used Particle Strength Exchange method (PSE) uses an approximation of the Laplacian operator in order to model diffusion. This approximation is based on an exchange of particles strength. Although DVM is particularly well suited to particle methods since it preserves their Lagrangian aspect, its major drawback stems in the fact that it suffers from severe... |
| Tipo: Text |
Palavras-chave: Particle method; Diffusion; DVM; PSE. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00159/27006/25254.pdf |
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| Tual, Nicolas; Carrere, N.; Davies, Peter; Bonnemains, T.; Lolive, E.. |
| In recent years, many tidal turbine projects have been developed using composites blades. Tidal turbine blades are subject to ocean forces and sea water aggressions, and the reliability of these components is crucial to the profitability of ocean energy recovery systems. The majority of tidal turbine developers have preferred carbon/epoxy blades, so there is a need to understand how prolonged immersion in the ocean affects these composites. In this study the long term behaviour of different carbon/epoxy composites has been studied using accelerated ageing tests. A significant reduction of composite strengths has been observed after saturation of water in the material. For longer immersions only small further changes in these properties occur. No... |
| Tipo: Text |
Palavras-chave: Carbon; Seawater ageing; Diffusion; Mechanical testing. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00278/38964/37504.pdf |
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| CHABERT,STEREN; SCIFO,PAOLA. |
| Diffusion Magnetic Resonance Imaging provides images of unquestionable diagnostic value. It is commonly used in the assessment of stroke and in white matter fiber tracking, among other applications. The diffusion coefficient has been shown to depend on cell concentration, membrane permeability, and cell orientation in the case of white matter or muscle fiber tracking; yet a clear relation between diffusion measurements and known physiological parameters is not established. The aim of this paper is to review hypotheses and actual knowledge on diffusion signal origin to provide assistance in the interpretation of diffusion MR images. Focus will be set on brain images, as most common applications of diffusion MRI are found in neuroradiology. Diffusion signal... |
| Tipo: Journal article |
Palavras-chave: Diffusion; Magnetic Resonance Imaging; Interpretation; Non Gaussian. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602007000500003 |
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| Famurewa, John Alaba Victor. |
| This study presents the thin layer drying behavior of unripe plantain slices (Musa paradisiaca) in a developed biomass cabinet dryer. The developed dryer provided an environment with an optimum operating temperature between 50 - 700C meant for drying agricultural materials. The use of thin layer drying mechanisms and equations contribute to better understanding of drying food materials. The thin layer drying behaviour of agricultural products was identified based on the mathematical models which describe the heat and mass transfer phenomena of the products. In order to select a suitable drying model, fourteen different thin layer drying models were fitted to experimental data. Fick’s second law was used to calculate the moisture diffusivity with some... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Food Engineering Thin layer; Mathematical modelling; Diffusion; Drying biomass fuel. |
| Ano: 2015 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3028 |
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| Silva,Cleide M. D. P. da S. e; Silva,Wilton P. da; Farias,Vera S. de O.; Gomes,Josivanda P.. |
| In this article, a methodology is used for the simultaneous determination of the effective diffusivity and the convective mass transfer coefficient in porous solids, which can be considered as an infinite cylinder during drying. Two models are used for optimization and drying simulation: model 1 (constant volume and diffusivity, with equilibrium boundary condition), and model 2 (constant volume and diffusivity with convective boundary condition). Optimization algorithms based on the inverse method were coupled to the analytical solutions, and these solutions can be adjusted to experimental data of the drying kinetics. An application of optimization methodology was made to describe the drying kinetics of whole bananas, using experimental data available in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Drying kinetics; Algorithm optimization; Diffusion; Porous media. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162012000200014 |
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| Lisboa,Cícera G. C. de; Gomes,Josivanda P.; Figueirêdo,Rossana M. F. de; Queiroz,Alexandre J. de M.; Diógenes,Adelino de M. G.; Melo,João C. S. de. |
| ABSTRACT The aim of this study was to obtain the effective diffusivity of yacon potato in fixed-bed dryer at different temperatures (50, 60 and 70 ºC) and drying air velocities (1.0, 1.5 and 2.0 m s-1). Non-linear regression analysis was performed by the Quasi-Newton method using the program Statistica 7.0, where the parameters of the models were estimated as a function of the drying air temperature. Approximation of Diffusion, Two Terms, Henderson & Pabis, and Page models fitted well the experimental data. Drying air temperature and speed influenced the drying time of the samples. The effective diffusivity increased with increasing temperature, ranging from 1.18 x 10-9 to 2.15 x 10-9 m2 s-1. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Smallanthus sonchifolia; Mathematical modelling; Diffusion. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000800564 |
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| Registros recuperados: 48 | |
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