arXiv subjects

Moochul Shin

Publications and source records attributed to Moochul Shin.

3 recordsLinked to original sources

arXiv2023

A New Paradigm Integrating the Concepts of Particle Abrasion and Breakage

This paper introduces a new paradigm that integrates the concepts of particle abrasion and breakage. Both processes can co-occur under loading as soil particles are subjected to friction as well as collisions between particles. Therefore, the significance of this integrating paradigm lies in its ability to address both abrasion and breakage in a single framework. The new paradigm is mapped out in a framework called the 'particle geometry space.' The x-axis corresponds to the surface-area-to-volume ratio ($A/V$), while the y-axis represents volume ($V$). This space facilitates a holistic characterization of the four-particle geometry features, i.e., shape (${\beta}$) and size ($D$) as well as surface area ($A$) and volume ($V$). Three distinct paths (abrasion, breakage, and equally-occurring abrasion and breakage processes), three limit lines (breakage line, sphere line, and average shape-conserving line), and five different zones are defined in the particle geometry space. Consequently, this approach enables us to systematically relate the extent of co-occurring abrasion and breakage to the particle geometry evolution.

cond-mat.soft↗

arXiv2021

Phenotypic Trait of Particle Geometries

People of a race appear different but share a 'phenotypic trait' due to a common genetic origin. Mineral particles are like humans: they appear different despite having a same geological origin. Then, do the particles have some sort of 'phenotypic trait' in the geometries as we do? How can we characterize the phenotypic trait of particle geometries? This paper discusses a new perspective on how the phenotypic trait can be discovered in the particle geometries and how the 'variation' and 'average' of the geometry can be quantified. The key idea is using the power-law between particle surface-area-to-volume ratio ($A/V$) and the particle volume ($V$) that uncovers the phenotypic trait in terms of ${\alpha}$ and ${\beta}^*$: From the log-transformed relation of $V = (A/V)^{\alpha} {\times} {\beta}^*$, the power value ${\alpha}$ represents the relation between shape and size, while the term ${\beta}^*$ (evaluated by fixing ${\alpha}$ = -3) informs the angularity of the average shape in the granular material. In other words, ${\alpha}$ represents the 'variation' of the geometry while ${\beta}^*$ is concerned with the 'average' geometry of a granular material. Furthermore, this study finds that $A/V$ and $V$ can be also used to characterize individual particle shape in terms of Wadell's true Sphericity ($S$). This paper also revisits the $M = A/V {\times} L/6$ concept originally introduced by Su et al. (2020) and finds the shape index $M$ is an extended form of $S$ providing additional information about the particle elongation. Therefore, the proposed method using $A/V$ and $V$ provides a unified approach that can characterize the particle geometry at multiple scales from granular material to a single particle. Ref.: Su, Y.F., Bhattacharya, S., Lee, S.J., Lee, C.H., Shin, M.: A new interpretation of three-dimensional particle geometry: M-A-V-L. Transp. Geotech. 23, 100328 (2020).

cond-mat.soft↗

arXiv2020

A New Interpretation of Three-Dimensional Particle Geometry: M-A-V-L

This study provides a new interpretation of 3D particle geometry that unravels the 'interrelation' of the four geometry parameters, i.e., morphology M, surface area A, volume V, and size L, for which a new formula, M = A/V$\times$L/6, is introduced to translate the 3D particle morphology as a function of surface area, volume, and size. The A/V$\times$L of a sphere is invariably 6, which is placed in the denominator of the formula, and therefore M indicates a relative morphological irregularity compared to the sphere. The minimum possible value of M is clearly one, and M may range approximately to three for coarse-grained mineral particles. Furthermore, the proposed formula, M = A/V$\times$L/6, enables to graphically preserve the four parameters' relations when plotting the geometry parameter distributions. This study demonstrates the approach with two plot spaces that represent (i) L vs. M and (ii) A/V vs. V, where A/V works as the messenger between these two spaces as A/V = M/L$\times$6. Therefore, this approach helps comprehensively address the four-dimensional aspects of the 3D particle geometry and better understand the parameters' combined influence on the mechanical behavior of granular materials. Keywords: 3D particle geometry; Morphology; Surface area; Volume; Size;

cond-mat.soft↗