Discrete particle simulation of particulate systems: A review of major applications and findings

Lunar sourcebook. A user's guide to the moon

A review on the angle of repose of granular materials

Review: Calibration of the discrete element method

Gas hydrates have received considerable attention due to their important role in flow assurance for the oil and gas industry, their extensive natural occurrence on Earth and extraterrestrial planets, and their significant applications in sustainable technologies including but not limited to gas and energy storage, gas separation, and water desalination Given not only their inherent structural flexibility depending on the type of guest gas molecules and formation conditions, but also the synthetic effects of a wide range of chemical additives on their properties, these variabilities could be exploited to optimise the role of gas hydrates This includes increasing their industrial applications, understanding and utilising their role in Nature, identifying potential methods for safely extracting natural gases stored in naturally occurring hydrates within the Earth, and for developing green technologies This review summarizes the different properties of gas hydrates as well as their formation and dissociation kinetics and then reviews the fast-growing literature reporting their role and applications in the aforementioned fields, mainly concentrating on advances during the last decade Challenges, limitations, and future perspectives of each field are briefly discussed The overall objective of this review is to provide readers with an extensive overview of gas hydrates that we hope will stimulate further work on this riveting field

Gas hydrates in sustainable chemistry

3D quantitative shape analysis on form, roundness, and compactness with μCT

http://bccw.cityu.edu.hk/jefwang/pdf/23.pdf

A novel three-dimensional contact model for granulates incorporating rolling and twisting resistances

http://bccw.cityu.edu.hk/jefwang/pdf/24.pdf

Micromorphology characterization and reconstruction of sand particles using micro X-ray tomography and spherical harmonics

Particle morphological features at different scale levels hold the key to understanding the geological origin and mechanical behaviour of natural sands In this context, it is necessary to characterise and quantify these morphological features by defining a series of reasonable descriptors In this study, based on X-ray micro-computed tomographic (μCT) images collected from a series of image-processing techniques, the authors first introduced spherical harmonic analysis to reconstruct a three-dimensional (3D) realistic surface of the sand particles Then 3D sphericity, roundness and fractal dimension were introduced to define the global form, local features and surface textures of the particle morphology Based on the spherical harmonic–reconstructed surface, a novel framework was established to measure the descriptors of 3D sphericity, roundness and fractal dimension of sand particles The 3D fractal dimension was an original descriptor used to characterise the fractal nature of the surface textures of r

Three-dimensional sphericity, roundness and fractal dimension of sand particles

SUMMARY

This article presents a fundamental study on the role of particle breakage on the shear behavior of granular soils using the three-dimensional (3-D) discrete element method. The effects of particle breakage on the stress ratio, volumetric strain, plastic deformation, and shear failure behavior of dense crushable specimens undergoing plane strain shearing conditions are thoroughly investigated through a variety of micromechanical analyses and mechanism demonstrations. The simulation of a granular specimen is based on the effective modeling of realistic fracture behavior of single soil particles, which is demonstrated by the qualitative agreement between the results from platen compression simulations and those from physical laboratory tests.



The simulation results show that the major effects of particle breakage include the reduction of volumetric dilation and peak stress ratio and more importantly the plastic deformation mechanisms and the shear failure modes vary as a function of soil crushability. Consistent macro- and micromechanical evidence demonstrates that shear banding and massive volumetric contraction depict the two end failure modes of a dense specimen, which is dominated by particle rearrangement–induced dilation and particle crushing–induced compression, respectively, with a more general case being the combination and competition of the two failure modes in the medium range of soil crushability and confining stress. However, it is further shown that a highly crushable specimen will eventually develop a shear band at a large strain because of the continuous decay of particle breakage. Copyright © 2011 John Wiley & Sons, Ltd.

Jianfeng Wang

Papers

3D quantitative shape analysis on form, roundness, and compactness with μCT

A novel three-dimensional contact model for granulates incorporating rolling and twisting resistances

Micromorphology characterization and reconstruction of sand particles using micro X-ray tomography and spherical harmonics

Three-dimensional sphericity, roundness and fractal dimension of sand particles

On the role of particle breakage in the shear failure behavior of granular soils by DEM