A Multi-Scale Analysis of Mechanical Strength of Solid Catalysts

2014 ◽  
Vol 997 ◽  
pp. 375-378
Author(s):  
Zhong Dong Tao ◽  
Kai Huang ◽  
Dong Fang Wu
Keyword(s):  
Mechanical Properties ◽  
Mechanical Strength ◽  
Fixed Bed ◽  
Future Research ◽  
Scale Analysis ◽  
Factor Analyses ◽  
Solid Catalysts ◽  
Multi Scale ◽  
Recent Developments ◽  
Multi Scale Analysis

Mechanical strength of solid catalysts involves a complex multi-scale system consisting of micro, pellet, pellet-packing and reactor scales. The damage evolution from micro to reactor scale leads to eventual rupture at the reactor level. A multi-scale framework for the mechanics of the fixed bed catalysts is proposed in this article. Some recent developments on the description of the mechanical properties on various scales, factor analyses of the mechanical properties on various scales, correlations between the damaging effects/mechanical properties on neighboring scales, etc. are reviewed, and the proposals for future research are also put forward.

scholarly journals Multi-scale analysis and modelling of collective migration in biological systems

2020 ◽  
Vol 375 (1807) ◽  
pp. 20190377
Author(s):  
Andreas Deutsch ◽  
Peter Friedl ◽  
Luigi Preziosi ◽  
Guy Theraulaz
Keyword(s):  
Biological Systems ◽  
Collective Behaviour ◽  
Coherent Motion ◽  
Collective Cell Migration ◽  
Scale Analysis ◽  
Collective Migration ◽  
Theme Issue ◽  
Multi Scale ◽  
Recent Developments ◽  
Multi Scale Analysis

Collective migration has become a paradigm for emergent behaviour in systems of moving and interacting individual units resulting in coherent motion. In biology, these units are cells or organisms. Collective cell migration is important in embryonic development, where it underlies tissue and organ formation, as well as pathological processes, such as cancer invasion and metastasis. In animal groups, collective movements may enhance individuals' decisions and facilitate navigation through complex environments and access to food resources. Mathematical models can extract unifying principles behind the diverse manifestations of collective migration. In biology, with a few exceptions, collective migration typically occurs at a ‘mesoscopic scale’ where the number of units ranges from only a few dozen to a few thousands, in contrast to the large systems treated by statistical mechanics. Recent developments in multi-scale analysis have allowed linkage of mesoscopic to micro- and macroscopic scales, and for different biological systems. The articles in this theme issue on ‘Multi-scale analysis and modelling of collective migration’ compile a range of mathematical modelling ideas and multi-scale methods for the analysis of collective migration. These approaches (i) uncover new unifying organization principles of collective behaviour, (ii) shed light on the transition from single to collective migration, and (iii) allow us to define similarities and differences of collective behaviour in groups of cells and organisms. As a common theme, self-organized collective migration is the result of ecological and evolutionary constraints both at the cell and organismic levels. Thereby, the rules governing physiological collective behaviours also underlie pathological processes, albeit with different upstream inputs and consequences for the group. This article is part of the theme issue ‘Multi-scale analysis and modelling of collective migration in biological systems’.

A Multi-Scale Analysis for an Evaluation of the Mechanical Properties of Composite Materials

2007 ◽  
Vol 334-335 ◽  
pp. 585-588
Author(s):  
Makoto Imura ◽  
Tetsusei Kurashiki ◽  
Hiroaki Nakai ◽  
Masaru Zako
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Composite Materials ◽  
Material Properties ◽  
Woven Fabric ◽  
Scale Analysis ◽  
Multi Scale ◽  
Woven Fabric Composites ◽  
Fabric Composites ◽  
Multi Scale Analysis

Fiber reinforced composite materials have been applied widely to many structures, because they have some advantages like easy handling, high specific strength, etc. The numerical method like finite element method has been applied to design and to evaluate the material properties and behavior as the development of Computer Aided Engineering. It is very difficult to calculate with accuracy not only in structural scale but also in detail material scale (for example, the order of fiber diameter) by the traditional FEM, becausecompositematerials like woven fabric composites have the geometrical complexityand the large difference between above mentioned scales. The development of multi-scale analysis method is one of the major topics in computational mechanics. Mesh superpositionis one of multi-scale analysis methods and is an effective method to solve the problems which have the large difference between the structure scale and the reinforcement scale. We have expanded the finite element mesh superposition method with 3 scales and have defined as M3 (Macro-Meso-Micro) method. In this paper, we have proposed a new approach method combined with M3 method and homogenized method to obtain the mechanical properties and to simulate the behavior of woven fabric composites. In addition, the elastic-plastic mechanics and the damage mechanics have been introduced into M3 method to investigate the effects of matrix-crack on the structural and material properties. From the numerical results, it is revealed that it is very useful for the evaluation of mechanical properties of composite materials.

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