ORCID Profile
0000-0002-9621-0277
Current Organisation
The University of Sydney Nano Institute
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Geomechanics and Resources Geotechnical Engineering | Resources Engineering and Extractive Metallurgy | Civil Geotechnical Engineering | Civil Engineering | Fluid mechanics and thermal engineering | Computational methods in fluid flow heat and mass transfer (incl. computational fluid dynamics) | Building Science and Techniques | Interdisciplinary Engineering not elsewhere classified | Construction Materials | Numerical modelling and mechanical characterisation | Numerical Modelling and Mechanical Characterisation | Petroleum and Reservoir Engineering | Environmental Rehabilitation (excl. Bioremediation) | Condensed Matter Characterisation Technique Development
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in Engineering | Climate Change Mitigation Strategies | Climate Change Adaptation Measures | Urban and Industrial Air Quality | Soils not elsewhere classified | Stone, Ceramics and Clay Materials | Cement and Concrete Materials | Natural Hazards in Urban and Industrial Environments | Urban and Industrial Water Management | Expanding Knowledge in the Earth Sciences | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Morphological characterisation of 2D packing with bi-disperse particles
Publisher: Springer Science and Business Media LLC
Date: 03-2021
A particle–water based model for water retention hysteresis
Publisher: Thomas Telford Ltd.
Date: 17-10-2013
Abstract: A particle–water discrete element based approach to describe water movement in partially saturated granular media is presented and tested. Water potential is governed by both capillary bridges, dominant at low saturations, and the pressure of entrapped air, dominant at high saturations. The approach captures the hysteresis of water retention during wetting and drainage by introducing the local evolution of liquid–solid contact angles at the level of pores and grains. Extensive comparisons against experimental data are presented. While these are made without the involvement of any fitting parameters, the method demonstrates relative high success by achieving a correlation coefficient of at least 82%, and mostly above 90%. For the tested materials with relatively mono-disperse grain size, the hysteresis of water retention during cycles of wetting and drainage has been shown to arise from the dynamics of solid–liquid contact angles as a function of local liquid volume changes.
Spherical ceramic pebbles subjected to multiple non-concentrated surface loads
Publisher: Elsevier BV
Date: 02-2012
Surface reconstruction with spherical harmonics and its application for single particle crushing simulations
Publisher: Elsevier BV
Date: 02-2022
Selective adsorption and transport of CO2–CH4 mixture under nano-confinement
Publisher: Elsevier BV
Date: 06-2023
Permeability of Uniformly Graded 3D Printed Granular Media
Publisher: American Geophysical Union (AGU)
Date: 03-2021
DOI: 10.1029/2020GL090728
Abstract: The present work explores water permeability of uniformly graded irregular grains using 3D printing with controlled shapes and fractal morphological features at low Reynold's number for viscous flow. From large amount of real 3D granular morphological data, a scaling law, in terms of fractal dimension, is found to be followed. With this universal law, sand grains with controlled fractal morphological features are generated using Spherical Harmonics, and then created using 3D printing technique for water permeability tests. A modified Kozeny‐Carman equation is proposed through more accurate determination of specific area, as a function of relative roughness and fractal dimension, than approximation using the volume‐equivalent sphere. By isolating the contributions from specific area, the shape coefficient is found to be insensitive to particle morphology. Through benchmarking the model prediction against experiments from both this work and past literature, we demonstrate the validity and wide applicability of the modified Kozeny‐Carman equation.
Atomistic Study of Dynamic Contact Angles in CO2–Water–Silica System
Publisher: American Chemical Society (ACS)
Date: 14-03-2019
DOI: 10.1021/ACS.LANGMUIR.9B00076
Abstract: The dynamic wetting for the CO
Tuning capillary flow in porous media with hierarchical structures
Publisher: AIP Publishing
Date: 03-2021
DOI: 10.1063/5.0038634
Abstract: Immiscible fluid–fluid displacement in porous media is of great importance in many engineering applications, such as enhanced oil recovery, agricultural irrigation, and geologic CO2 storage. Fingering phenomena, induced by the interface instability, are commonly encountered during displacement processes and somehow detrimental since such hydrodynamic instabilities can significantly reduce displacement efficiency. In this study, we report a possible adjustment in pore geometry, which aims to suppress the capillary fingering in porous media with hierarchical structures. Through pore-scale simulations and theoretical analysis, we demonstrate and quantify the combined effects of wettability and hierarchical geometry on displacement patterns, showing a transition from fingering to compact mode. Our results suggest that with a higher porosity of the second-order porous structure, the displacement can stay compact across a wider range of wettability conditions. Combined with our previous work on viscous fingering in such media, we can provide a complete insight into the fluid-fluid displacement control in hierarchical porous media, across a wide range of flow conditions from capillary- to viscous-dominated modes. The conclusions of this work can benefit the design of microfluidic devices and tailoring porous media for better fluid displacement efficiency at the field scale.
Status of ceramic breeder pebble bed thermo-mechanics R&D and impact on breeder material mechanical strength
Publisher: Elsevier BV
Date: 08-2012
Discrete element simulation of dynamic behaviour of partially saturated sand
Publisher: Springer Science and Business Media LLC
Date: 13-08-2016
Numerical and experimental characterization of ceramic pebble beds under cycling mechanical loading
Publisher: Elsevier BV
Date: 11-2016
Pore-scale modelling of gravity-driven drainage in disordered porous media
Publisher: Elsevier BV
Date: 05-2019
Evaporation Limited Radial Capillary Penetration in Porous Media
Publisher: American Chemical Society (ACS)
Date: 13-09-2016
DOI: 10.1021/ACS.LANGMUIR.6B02404
Abstract: The capillary penetration of fluids in thin porous layers is of fundamental interest in nature and various industrial applications. When capillary flows occur in porous media, the extent of penetration is known to increase with the square root of time following the Lucas-Washburn law. In practice, volatile liquid evaporates at the surface of porous media, which restricts penetration to a limited region. In this work, on the basis of Darcy's law and mass conservation, a general theoretical model is developed for the evaporation-limited radial capillary penetration in porous media. The presented model predicts that evaporation decreases the rate of fluid penetration and limits it to a critical radius. Furthermore, we construct a unified phase diagram that describes the limited penetration in an annular porous medium, in which the boundaries of outward and inward liquid are predicted quantitatively. It is expected that the proposed theoretical model will advance the understanding of penetration dynamics in porous media and facilitate the design of engineered porous architectures.
Two-dimensional modeling of the self-limiting oxidation in silicon and tungsten nanowires
Publisher: Elsevier BV
Date: 09-2016
Wettability impacts residual trapping of immiscible fluids during cyclic injection
Publisher: Cambridge University Press (CUP)
Date: 25-04-2023
DOI: 10.1017/JFM.2023.222
Abstract: Understanding the hysteretic behaviour in fluid–fluid displacement processes in porous media is critical in many engineering applications. In this work, we study the quasi-static immiscible displacement process in two-dimensional porous media during cyclic injections in the context of carbon geosequestration. The role of wettability on the residual trapping of CO $_2$ is investigated numerically using an extended interface tracking algorithm. Despite that higher CO $_2$ saturation can be achieved in CO $_2$ -wet porous media after the first CO $_2$ injection, the majority of CO $_2$ is found to be unstable and can be mobilised during subsequent water injection processes. An improvement in the residual trapping of CO $_2$ is observed as the number of injection cycles increases, which is associated with the dispersion of continuous CO $_2$ ganglia into numerous smaller blobs. Compared with either water-wet or CO $_2$ -wet porous media, it is found that less CO $_2$ is trapped within the neutral-wet ones at equilibrium state after a sufficient number of injection cycles. The hysteretic behaviour of saturation between water/CO $_2$ injection cycles is found to follow an exponential decay, which eventually reaches a finite value. This process corresponds to the shift of the mobile region during displacement from typical capillary fingering to a less ramified regime, which ultimately converges towards main flow channels. This work highlights the hysteretic behaviour during cyclic injections, providing insights on the wettability impacts on multiphase flow in porous media, which is of great importance in applications such as carbon geosequestration and geological hydrogen storage.
Modelling Imbibition Processes in Heterogeneous Porous Media
Publisher: Springer Science and Business Media LLC
Date: 10-09-2018
The Role of Surface Structure in Normal Contact Stiffness
Publisher: Springer Science and Business Media LLC
Date: 23-10-2015
Towards the end of drying of granular materials: enhanced evaporation and drying-induced collapse
Publisher: Wiley
Date: 19-04-2021
Effective thermal conductivity of a compacted pebble bed in a stagnant gaseous environment: An analytical approach together with DEM
Publisher: Elsevier BV
Date: 05-2018
Particle-shape-, temperature-, and concentration-dependent thermal conductivity and viscosity of nanofluids
Publisher: American Physical Society (APS)
Date: 26-04-2019
Precipitation of (Ti, Zr, Nb, Ta, Hf)C high entropy carbides in a steel matrix
Publisher: Elsevier BV
Date: 03-2020
Maximum likelihood estimation for nanoindentation on sodium aluminosilicate hydrate gel of geopolymer under different silica modulus and curing conditions
Publisher: Elsevier BV
Date: 10-2020
Effects of variable injection rate on reservoir responses and implications for CO2 storage in saline aquifers
Publisher: Wiley
Date: 13-05-2019
DOI: 10.1002/GHG.1888
X-ray tomography investigations of mono-sized sphere packing structures in cylindrical containers
Publisher: Elsevier BV
Date: 08-2017
Scalable Surface Area Characterization by Electrokinetic Analysis of Complex Anion Adsorption
Publisher: American Chemical Society (ACS)
Date: 11-12-2014
DOI: 10.1021/LA503581E
Abstract: By means of the in situ electrokinetic assessment of aqueous particles in conjunction with the addition of anionic adsorbates, we develop and examine a new approach to the scalable characterization of the specific accessible surface area of particles in water. For alumina powders of differing morphology in mildly acidic aqueous suspensions, the effective surface charge was modified by carboxylate anion adsorption through the incremental addition of oxalic and citric acids. The observed zeta potential variation as a function of the proportional reagent additive was found to exhibit inverse hyperbolic sine-type behavior predicted to arise from monolayer adsorption following the Grahame-Langmuir model. Through parameter optimization by inverse problem solving, the zeta potential shift with relative adsorbate addition revealed a nearly linear correlation of a defined surface-area-dependent parameter with the conventionally measured surface area values of the powders, demonstrating that the proposed analytical framework is applicable for the in situ surface area characterization of aqueous particulate matter. The investigated methods have advantages over some conventional surface analysis techniques owing to their direct applicability in aqueous environments at ambient temperature and the ability to modify analysis scales by variation of the adsorption cross section.
Numerical study on mechanical and hydraulic behaviour of blast-induced fractured rock
Publisher: Springer Science and Business Media LLC
Date: 27-03-2019
Mechanical properties in crumple-formed paper derived materials subjected to compression
Publisher: Elsevier BV
Date: 06-2017
Phase change material thermal energy storage design of packed bed units
Publisher: Elsevier BV
Date: 07-2022
Failure initiation and propagation of Li4SiO4 pebbles in fusion blankets
Publisher: Elsevier BV
Date: 2013
Dynamics of Viscous Entrapped Saturated Zones in Partially Wetted Porous Media
Publisher: Springer Science and Business Media LLC
Date: 06-07-2018
Influence of multiscale surface roughness on permeability in fractures
Publisher: American Physical Society (APS)
Date: 03-02-2022
An FDEM study of particle breakage under rotational point loading
Publisher: Elsevier BV
Date: 05-2019
Mechanics of binary crushable granular assembly through discrete element method
Publisher: Elsevier BV
Date: 12-2016
Tuning capillary penetration in porous media: Combining geometrical and evaporation effects
Publisher: Elsevier BV
Date: 08-2018
Contact behaviour of simulated rough spheres generated with spherical harmonics
Publisher: Elsevier BV
Date: 06-2020
A reliable approach for calculating thermophysical properties of liquid using molecular dynamics simulations
Publisher: Elsevier BV
Date: 11-2018
Performance optimization for shell-and-tube PCM thermal energy storage
Publisher: Elsevier BV
Date: 08-2020
Physical properties of Australian hurd used as aggregate for hemp concrete
Publisher: Elsevier BV
Date: 09-2020
Explosively driven hierarchical particle jetting
Publisher: Elsevier BV
Date: 07-2019
Computer simulation of packing structure in pebble beds
Publisher: Elsevier BV
Date: 12-2010
3d tomography analysis of the packing structure of spherical particles in slender prismatic containers
Publisher: Walter de Gruyter GmbH
Date: 25-12-2019
DOI: 10.3139/146.111814
Abstract: In granular media, topological features are known to determine the effective material properties and boundary behavior when interacting with other structural components. X-ray computed tomography results are reported on sphere packing structures in slender prismatic containers ( X = 20, Y = Z = 80 mm), filled and vibrated with both monosized spheres (diameter d = 2.4 mm), Exp. (M), and polydisperse spheres (1 mm d 1.25 mm), Exp. (P). Packing structures were characterized by void fraction distributions, coordination numbers, contact angle distributions and Voronoi packing fractions. In (M), an almost perfect hexagonal dense packing exists in the total volume, associated with a packing fraction γ t ≈0.68. In additional packing experiments, large γ t values were achieved as well. Although the d spread in (P) is relatively small, significantly different results are obtained: γ t ≈0.62, regular structures are restricted to narrow wall zones and distributions in the container volume are nonhomogeneous. It is argued that the small degree of ordered structure is a characteristic feature of polydispersity for efficiently vibrated sphere packings.
Pore-scale lattice Boltzmann simulation of CO2-CH4 displacement in shale matrix
Publisher: Elsevier BV
Date: 09-2023
Stress-dependent frequency response of conductive granular materials
Publisher: IEEE
Date: 10-2016
Dynamic contact angle hysteresis in liquid bridges
Publisher: Elsevier BV
Date: 10-2018
Thermo-mechanical analysis of pebble beds in HELICA mock-up experiments
Publisher: Elsevier BV
Date: 12-2008
Evolution of fabric in spherical granular assemblies under the influence of various loading conditions through DEM
Publisher: Springer Science and Business Media LLC
Date: 26-02-2020
Packing of wet monodisperse spheres
Publisher: Elsevier BV
Date: 2021
Electrical Percolation in Conductive Granular Media
Publisher: American Scientific Publishers
Date: 12-2018
Modified smoothed particle hydrodynamics approach for modelling dynamic contact angle hysteresis
Publisher: Springer Science and Business Media LLC
Date: 22-02-2019
Analytical solutions for elastic response of coated mesoporous materials to pore pressure
Publisher: Elsevier BV
Date: 10-2016
Cyclic behavior of ceramic pebble beds under mechanical loading
Publisher: Elsevier BV
Date: 09-2018
Contact mechanics of fractal surfaces by spline assisted discretisation
Publisher: Elsevier BV
Date: 05-2015
The onset of shock-induced particle jetting
Publisher: Elsevier BV
Date: 08-2018
Morphodynamics of a dense particulate medium under radial explosion
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9SM02150G
Abstract: In this paper, we investigate the initiation and growth of instability patterns arising from the shock loaded internal surfaces of granular rings confined in a Hele-Shaw cell using both experimental and numerical approaches.
Experimental and numerical determination of mechanical properties of polygonal wood particles and their flow analysis in silos
Publisher: Springer Science and Business Media LLC
Date: 17-09-2013
The pore-load modulus of ordered nanoporous materials with surface effects
Publisher: AIP Publishing
Date: 03-2016
DOI: 10.1063/1.4945441
Abstract: Gas and liquid adsorption-induced deformation of ordered porous materials is an important physical phenomenon with a wide range of applications. In general, the deformation can be characterized by the pore-load modulus and, when the pore size reduces to nanoscale, it is affected by surface effects and shows prominent size-dependent features. In this Letter, the influence of surface effects on the elastic properties of ordered nanoporous materials with internal pressure is accounted for in a single pore model. A porosity and surface elastic constants dependent closed form solution for the size dependent pore-load modulus is obtained and verified by finite element simulations and available experimental results. In addition, it is found to depend on the geometrical arrangement of pores. This study provides an efficient tool to analyze the surface effects on the elastic response of ordered nanoporous materials.
Effect of grain shape on quasi-static fluid-fluid displacement in porous media
Publisher: Wiley
Date: 18-12-2020
A pore-resolved interface tracking algorithm for simulating multiphase flow in arbitrarily structured porous media
Publisher: Elsevier BV
Date: 04-2022
Stress-dependent electrical impedance behaviours at fractal rough interfaces
Publisher: IOP Publishing
Date: 28-04-2021
Abstract: This work investigates interfacial electro-mechanical properties, including electrical contact resistance, interfacial capacitance and characteristic frequency of contacts formed with various surface structures. Fractal rough surfaces were generated and characterised by fractal dimension and root-mean-square (RMS) roughness. The rough surface with a thin oxide layer was compressed by the rigid flat to form a capacitor. Electrical impedances of this contact capacitor were simulated using the finite element method across a wide range of frequencies. A power-law relationship was found between the electrical contact resistance and applied compression load. An analytical model is proposed to capture the interfacial capacitance behaviour with increasing contact loads, revealing a transition of predominated modes for the capacitance. Higher fractal dimension yields smaller overall capacitance in the gap dominant and transition zones. The dependence of the characteristic frequency on compression was found to follow a power-law function at the low load range. It is found that the exponent and magnitude of obtained power-law relations show strong correlations to the fractal dimension and RMS roughness, respectively. Results of this work provide insights into developing a potential impedance measurement protocol to determine the thickness of the oxide layer on conductive fractal rough surfaces.
Stress-dependent electrical transport and its universal scaling in granular materials
Publisher: Elsevier BV
Date: 07-2018
Thermo-mechanical modelling of pebble bed–wall interfaces
Publisher: Elsevier BV
Date: 2010
Cracking to curling transition in drying colloidal films
Publisher: Springer Science and Business Media LLC
Date: 10-2020
Rupture of Liquid Bridges on Porous Tips: Competing Mechanisms of Spontaneous Imbibition and Stretching
Publisher: American Chemical Society (ACS)
Date: 04-11-2020
Radical-functionalized plasma polymers: Stable biomimetic interfaces for bone implant applications
Publisher: Elsevier BV
Date: 09-2019
Emergence of unstable invasion during imbibition in regular porous media
Publisher: Cambridge University Press (CUP)
Date: 04-05-2022
DOI: 10.1017/JFM.2022.336
Abstract: The unstable fluid–fluid displacement patterns in porous media with rough invasion fronts and trapping of the defending phase are often observed in drainage, i.e. when the solid is non-wetting to the invading phase. On the other hand, during imbibition, compact and faceted growth is expected in regular porous media with geometrically homogeneous pore structure. Here, we report the irregular growth of invading fluid during the imbibition process in two-dimensional regular porous media. The ramified invasion morphology associated with thin fingers is reminiscent of capillary fingering. Through examining the capillary pressure signals and the type of pore-scale invasion mechanisms, the fundamental differences between faceted growth and irregular invasion are revealed. By analysing the pore-scale invasion mechanisms, a phase diagram describing the dominance of different invasion events is proposed. Through conducting systematic quasi-static radial injection simulations across a wide range of porosity and wettability, excellent agreement is observed on the transition boundary from faceted and compact displacement patterns to irregular and dendritic invasion morphologies. This is reflected by the overlap of the transition boundaries from analytical prediction, type of pore-scale invasion events, and macroscopic morphology quantified by the fractal dimension. This work provides new insights on the role of geometrical features of solid structures during multiphase flow with emphasis on the porosity and wettability. The findings could assist in guiding the design of microfluidic devices to control deterministically the multiphase flow, transport and reaction processes.
Improved Mathematical Model for Analysis of the Payne Effect of Magnetorheological Elastomers
Publisher: American Society of Civil Engineers (ASCE)
Date: 09-2018
Static friction between rigid fractal surfaces
Publisher: American Physical Society (APS)
Date: 17-09-2015
A micromechanical model for effective conductivity in granular electrode structures
Publisher: Springer Science and Business Media LLC
Date: 10-2013
3D printable geomaterials
Publisher: Thomas Telford Ltd.
Date: 04-2016
Abstract: One of the many attributes of three-dimensional (3D) printing is the ability to produce particles with independent control of morphology and material properties, parameters that are inexorably entwined in naturally occurring geomaterials. In this paper the 3D printing of surrogate granular materials is described, with ex les of the particles produced, and results are presented showing their ability to capture real soil behaviour. Three approaches are demonstrated for the 3D generation of model grains. The first method involves the superimposition of a fractal surface with higher level stochastic features on the face of a closed volume, such as a geodesic spheroid. The second method involves the use of Fourier descriptors or fractal geometry generated from two-dimensional (2D) cross-sections and their interpolation to produce simulated geomaterial particles in three dimensions. The third method involves the generation of complex particles by the aggregation of polyhedral elements such as cubes or octahedra which is suitable for the simulation and fabrication of porous or branching particles. Triaxial tests have been performed on particles produced by the second method, which most readily allows input parameters to be obtained from natural geomaterials. Results of these tests show the ability of the printed particles to reproduce soil behaviour, and demonstrate the effect of particle shape on the material response. Finally, applications of the fabrication of surrogate materials by 3D printing are discussed, for use as standardised, printable geomaterials in future up-scaled geotechnical experiments and other geomechanical research.
Dual hierarchical particle jetting of a particle ring undergoing radial explosion
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8SM00209F
Abstract: We study experimentally the formation of a dual hierarchical jetting pattern in dry dense particle media subjected to the radially ergent shock loadings in a radial Hele-Shaw cell.
Discrete element simulation of surface mechanical attrition treatment with rough-surface sonotrode
Publisher: Elsevier BV
Date: 10-2019
Effect of Wetting Transition during Multiphase Displacement in Porous Media
Publisher: American Chemical Society (ACS)
Date: 18-02-2020
Identification of material parameters of a thermo-mechanical model for pebble beds in fusion blankets
Publisher: Elsevier BV
Date: 02-2007
The effects of packing structure on the effective thermal conductivity of granular media: A grain scale investigation
Publisher: Elsevier BV
Date: 08-2019
Desiccation crack formation and prevention in thin bentonite layers
Publisher: Thomas Telford Ltd.
Date: 12-2022
Abstract: Desiccation cracks in clay play an important role in many geoenvironmental applications such as clay liners in engineered landfills, preferential flows and contaminant transport. In this study, a comprehensive series of experiments was conducted to investigate the desiccation cracks due to the combined effects of initial water content and layer thickness on bentonite clay. Slurries of bentonite were prepared with initial water contents ranging from 1200 to 2200%. The slurry was placed in a glass Petri dish and dried at a temperature of 30 ± 2°C. Results from the experiments were illustrated in a phase diagram, and it was found that the interplay between the initial water content and layer thickness has a significant effect on the formation and prevention of desiccation cracks. More specifically, a phase boundary distinguishing between cracked and non-cracked s les was obtained in the constructed phase diagram. A theoretical model based on the critical cracking thickness was developed and then was used to predict this observed phase boundary. Furthermore, a detailed morphology of crack patterns was investigated by employing image analysis techniques followed by statistical analyses. Findings from this study have potential use in clay liner design, where bentonite is used as the main material, as well as in other problems associated with drying soils.
CO2-TBAB semi-clathrate hydrate dissociation behaviour in individual capsules: A new two-stage numerical model and parametric study
Publisher: Elsevier BV
Date: 08-2023
Applying grid nanoindentation and maximum likelihood estimation for N-A-S-H gel in geopolymer paste: Investigation and discussion
Publisher: Elsevier BV
Date: 09-2020
Mechanics of a crushable pebble assembly using discrete element method
Publisher: Elsevier BV
Date: 11-2012
Influence of plate material on the contact strength of Li4SiO4 pebbles in crush tests and evaluation of the contact strength in pebble–pebble contact
Publisher: Elsevier BV
Date: 03-2013
Numerical investigation of microscale dynamic contact angles of the CO2–water–silica system using coarse-grained molecular approach
Publisher: Springer Science and Business Media LLC
Date: 03-07-2020
Experimental Observations of Stress-Driven Grain Boundary Migration
Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-12-2009
Abstract: Classical models of fine-grained metals view grain boundaries as static objects, but this view has been challenged by recent experimental observations. Drawing on techniques used by the fracture mechanics community, Rupert et al. (p. 1686 ) present experiments on freestanding aluminum films that show specific geometries cause either stress or strain concentrations on deformation. Confirming recent simulations, shear stresses were found to be a key driver of grain boundary motion.
Coarse-grained modeling of multiphase interactions at microscale
Publisher: AIP Publishing
Date: 26-09-2018
DOI: 10.1063/1.5038903
Abstract: The objective of this study is to develop and test a coarse-grained molecular dynamics framework to model microscale multiphase systems with different inter-particle interactions and recover emerging thermodynamic and mechanical properties at the microscale. A water-vapor model and a fused silica model are developed to demonstrate the capability of our framework. The former can reproduce the water density and surface tension over a wide range of temperatures the latter can reproduce experimental density, tensile strength, and Young’s modulus of fused silica. Therefore, the deformable solid model is implemented in the proposed framework. Validations of spatial scaling methods for solid, liquid, and multiphase systems suggest that the proposed framework can be calibrated at an arbitrary microscale and used at a different length scale without recalibration. Different values of wettability for a solid-liquid-vapor system that is characterized by the contact angle can be achieved by changing the solid-liquid inter-particle potential. Thanks to these features, the proposed coarse-grained molecular dynamics framework can potentially find applications in modeling systems in which multiple phases coexist and have substantial interactions.
Thermal Discrete Element Analysis of EU Solid Breeder Blanket Subjected to Neutron Irradiation
Publisher: Informa UK Limited
Date: 08-2014
DOI: 10.13182/FST13-727
Effects of surface structure deformation on static friction at fractal interfaces
Publisher: Thomas Telford Ltd.
Date: 13-05-2013
Abstract: The evolution of fractal surface structures with flattening of asperities was investigated using isotropically roughened aluminium surfaces loaded in compression. It was found that asperity litude, mean roughness and fractal dimension decrease through increased compressive stress and number of loading events. Of the s les tested, surfaces subjected to an increased number of loading events exhibited the most significant surface deformation and were observed to exhibit higher levels of static friction at an interface with a single-crystal flat quartz substrate. This suggests that the frequency of grain reorganisation events in geomaterials plays an important role in the development of intergranular friction. Fractal surfaces were numerically modelled using Weierstrass–Mandelbrot-based functions. From the study of frictional interactions with rigid flat opposing surfaces it was apparent that the effect of surface fractal dimension is more significant with increasing dominance of adhesive mechanisms.
A Modified Weber Number Capturing the Bouncing–Wetting Transition of Droplet Impact on Rough Surfaces
Publisher: Wiley
Date: 02-03-2023
Abstract: In this work, the effects of surface properties on bouncing–wetting transition of water droplet impacting rough surfaces in the Weber number ( We ) range from 18 to 221 are experimentally investigated. The correlation between impact outcomes and We is examined with an empirical function, and an impact outcome transition from bouncing to no bouncing is identified with the increase of We . The results suggest that a higher surface area ratio promotes the bouncing to no bouncing transition on s le surfaces used in this study. To quantify the effects of surface wetting area on the transitions of droplet impact regimes, a modified Weber number, We *, is proposed by taking the actual surface area into account. Results show that the regime transitions of droplet impact on s les of different surface area ratios can be unified by the We *. This study reveals the significance of actual surface area and the resultant adhesion force on the droplet impact dynamics on random rough surfaces.
Solution based synthesis of mixed-phase materials in the Li2TiO3–Li4SiO4 system
Publisher: Elsevier BV
Date: 2015
Discrete element modelling of pebble beds: With application to uniaxial compression tests of ceramic breeder pebble beds
Publisher: Elsevier BV
Date: 02-2010
Discrete element method for effective thermal conductivity of packed pebbles accounting for the Smoluchowski effect
Publisher: Elsevier BV
Date: 02-2018
Modeling the effective conductivity of the solid and the pore phase in granular materials using resistor networks
Publisher: Elsevier BV
Date: 06-2019
Modes of wall induced granular crystallisation in vibrational packing
Publisher: Springer Science and Business Media LLC
Date: 13-03-2019
Towards the End of Drying of Granular Materials: Enhanced Evaporation and Drying‐Induced Collapse
Publisher: American Geophysical Union (AGU)
Date: 07-2021
DOI: 10.1029/2021WR030125
Abstract: We experimentally study the drying of loosely packed wet glass beads at low initial water content. The drying rate is found to decrease at the start, corresponding to the decreasing rate period controlled by vapor diffusion, followed by a deviation in drying rate from the diffusion limited evaporation. The propagation of drying front associated with a sharp saturation gradient is identified through both image analysis and magnetic resonance imaging technique. The drying‐induced collapse of granular medium is observed and quantified. The concentrated collapse at the end of drying suggests the existence of liquid in the form of liquid bridges in the apparent dry region until the end of drying process. Collapse event is found to be local, that is, a clear boundary can be identified for each collapse event, below which the loosely packed medium remains intact. This indicates the existence of a saturation gradient in the apparent dry region. The drying dynamics and collapse statistics suggest that the observed transition of drying regimes is due to Kelvin effect. This work demonstrates for the first time the drying enhancement phenomenon due to Kelvin effect even for grains with size of hundreds of micrometers, and provides insights on the drying process of partially saturated granular materials, especially near the final period of evaporation.
Disorder characterization of porous media and its effect on fluid displacement
Publisher: American Physical Society (APS)
Date: 29-03-2019
Modelling wrinkling interactions produced by patterned defects in metal thin films
Publisher: Elsevier BV
Date: 09-2015
Enhancing Spontaneous Droplet Motion on Structured Surfaces with Tailored Wedge Design
Publisher: Wiley
Date: 27-05-2020
Numerical Investigation of Compressive Stress and Wettability Effects on Fluid Transport in Polymer Electrolyte Membrane Fuel Cell Porous Layers
Publisher: Wiley
Date: 06-10-2022
Abstract: The performance of polymer electrolyte membrane fuel cells (PEMFCs) is greatly influenced by the residual water content generated during the cell operation. A comprehensive understanding of water management at the interfacial regions of PEMFC components is critical for elevating the efficiency of PEMFCs. Herein, the liquid transport and accumulation at the interfacial region of 2D microporous layer (MPL) and catalyst layer (CL) are investigated numerically, considering the effects of compression stress, porosity, and wettability. The numerical scheme is assembled by finite element method (for interfacial contact mechanics) and lattice Boltzmann method (for multiphase flow and permeability calculation). Different levels of compression stress derived from fuel cell assembly pressure are applied on the MPL/CL components, which consequently lead to variations in the pore size distribution and porosity change of the MPL/CL. The results highlight the importance of considering porosity change in the compression process, where increasing compression stress significantly decreases the liquid saturation in the MPL and interfacial gap region. Additionally, strong hydrophobicity can alleviate the heterogeneity of liquid accumulation at the MPL/CL interfacial region. The liquid and gas relative permeability are also investigated to assess the liquid drainage and fuel supply efficiency with different compression stress.
Size-Dependent Crush Analysis of Lithium Orthosilicate Pebbles
Publisher: Informa UK Limited
Date: 08-2014
DOI: 10.13182/FST13-737
Influence of gas pressure on the effective thermal conductivity of ceramic breeder pebble beds
Publisher: Elsevier BV
Date: 05-2017
Thermo-mechanical analyses of HELICA and HEXCALIBER mock-ups
Publisher: Elsevier BV
Date: 04-2009
Effect of Grain Shape on Quasi‐Static Fluid‐Fluid Displacement in Porous Media
Publisher: American Geophysical Union (AGU)
Date: 04-2021
DOI: 10.1029/2020WR029415
Abstract: We study how grain shapes impact multiphase flow in porous media in the quasi‐static regime using an extended pore‐network model. The algorithm allows the explicit determination of different types of pore‐scale instabilities and tracks the interface motion during the fluid‐fluid displacement process. It also includes the volume capacitance model, such that both the evolution of capillary pressure signal and sizes of Haines jumps can be captured. Further, it considers the pinning of menisci at sharp edges of grains, through which the distribution of effective contact angles can be obtained. Simulations are carried out across a wide range of wetting conditions for different particle shapes. Our results show that the effective contact angle distribution during displacement widens as the grain becomes more angular, which consequently modifies the macroscopic fluid invasion morphology. By analyzing various characteristic metrics during displacement, including capillary pressure signal, Haines jump size distribution, and fractal dimension, our results highlight the profound influence of particle shape on the multiphase flow.
Microwave Regenerable Nickel, Zinc Co-doped Nitrogen-Coordinated Porous Carbon Catalyst for Nitrogen Fixation
Publisher: American Chemical Society (ACS)
Date: 12-09-2023
Discrete Element Analysis of Heat Transfer in the Breeder Beds of the European Solid Breeder Blanket Concept
Publisher: Informa UK Limited
Date: 22-03-2019
Multiscale modeling of the effective elastic properties of fluid-filled porous materials
Publisher: Elsevier BV
Date: 05-2019
Crush probability analysis of ceramic breeder pebble beds under mechanical stresses
Publisher: Elsevier BV
Date: 10-2011
Three-dimensional modeling of the mechanical property of linearly elastic open cell foams
Publisher: Elsevier BV
Date: 12-2005
The role of particle morphology on concrete fracture behaviour: A meso-scale modelling approach
Publisher: Elsevier BV
Date: 08-2020
Modeling acoustic emission in the Brazilian test using moment tensor inversion
Publisher: Elsevier BV
Date: 07-2020
Analytical estimation of the effective thermal conductivity of a granular bed in a stagnant gas including the Smoluchowski effect
Publisher: Springer Science and Business Media LLC
Date: 31-08-2019
Mechanics of binary and polydisperse spherical pebble assembly
Publisher: Elsevier BV
Date: 08-2012
Fingering patterns in hierarchical porous media
Publisher: American Physical Society (APS)
Date: 09-03-2020
Roughness effects of gas diffusion layers on droplet dynamics in PEMFC flow channels
Publisher: Elsevier BV
Date: 07-2020
Predicting mechanical properties of 316L stainless steel subjected to SMAT: A sequential DEM-FEM investigation
Publisher: Elsevier BV
Date: 03-2021
An improved semi-analytical solution for stress at round-tip notches
Publisher: Elsevier BV
Date: 11-2015
An LBM-PNM framework for immiscible flow: With applications to droplet spreading on porous surfaces
Publisher: Elsevier BV
Date: 06-2020
Phase transitions and cyclic pseudotachylyte formation in simulated faults
Publisher: Informa UK Limited
Date: 02-04-2012
Microstructure and mechanical properties of hard Acrocomia mexicana fruit shell
Publisher: Springer Science and Business Media LLC
Date: 25-06-2018
DOI: 10.1038/S41598-018-27282-8
Abstract: Fruit and nut shells can exhibit high hardness and toughness. In the peninsula of Yucatan, Mexico, the fruit of the Cocoyol palm tree ( Acrocomia mexicana ) is well known to be very difficult to break. Its hardness has been documented since the 1500 s, and is even mentioned in the popular Maya legend The Dwarf of Uxmal. However, until now, no scientific studies quantifying the mechanical performance of the Cocoyol endocarp has been found in the literature to prove or disprove that this fruit shell is indeed “very hard”. Here we report the mechanical properties, microstructure and hardness of this material. The mechanical measurements showed compressive strength values of up to ~150 and ~250 MPa under quasi-static and high strain rate loading conditions, respectively, and microhardness of up to ~0.36 GPa. Our findings reveal a complex hierarchical structure showing that the Cocoyol shell is a functionally graded material with distinctive layers along the radial directions. These findings demonstrate that structure-property relationships make this material hard and tough. The mechanical results and the microstructure presented herein encourage designing new types of bioinspired superior synthetic materials.
Pore-scale modeling of multiphase flow in porous media using a conditional generative adversarial network (cGAN)
Publisher: AIP Publishing
Date: 12-2022
DOI: 10.1063/5.0133054
Abstract: Multiphase flow in porous media is involved in various natural and industrial applications, including water infiltration into soils, carbon geosequestration, and underground hydrogen storage. Understanding the invasion morphology at the pore scale is critical for better prediction of flow properties at the continuum scale in partially saturated permeable media. The deep learning method, as a promising technique to estimate the flow transport processes in porous media, has gained significant attention. However, existing works have mainly focused on single-phase flow, whereas the capability of data-driven techniques has yet to be applied to the pore-scale modeling of fluid–fluid displacement in porous media. Here, the conditional generative adversarial network is applied for pore-scale modeling of multiphase flow in two-dimensional porous media. The network is trained based on a data set of porous media generated using a particle-deposition method, with the corresponding invasion morphologies after the displacement processes calculated using a recently developed interface tracking algorithm. The results demonstrate the capability of data-driven techniques in predicting both fluid saturation and spatial distribution. It is also shown that the method can be generalized to estimate fluid distribution under different wetting conditions and particle shapes. This work represents the first effort at the application of the deep learning method for pore-scale modeling of immiscible fluid displacement and highlights the strength of data-driven techniques for surrogate modeling of multiphase flow in porous media.
Experimental and numerical investigation on hydrothermal performance of nanofluids in micro-tubes
Publisher: Elsevier BV
Date: 02-2020
Contact stiffness of multiscale surfaces by truncation analysis
Publisher: Elsevier BV
Date: 10-2017
Universality of the emergent scaling in finite random binary percolation networks
Publisher: Public Library of Science (PLoS)
Date: 16-02-2017
An experimental investigation on cemented sand particles using different loading paths: Failure modes and fabric quantifications
Publisher: Elsevier BV
Date: 10-2020
A Discrete Element Method to simulate the mechanical behavior of ellipsoidal particles for a fusion breeding blanket
Publisher: Elsevier BV
Date: 10-2017
Interfacial electro-mechanical behaviour at rough surfaces
Publisher: Elsevier BV
Date: 12-2016
Static friction at fractal interfaces
Publisher: Elsevier BV
Date: 2016
Tailoring porous media for controllable capillary flow
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.JCIS.2018.12.068
Abstract: Control of capillary flow through porous media has broad practical implications. However, achieving accurate and reliable control of such processes by tuning the pore size or by modification of interface wettability remains challenging. Here we propose that the liquid flow by capillary penetration can be accurately adjusted by tuning the geometry of porous media. On the basis of Darcy's law, a general framework is proposed to facilitate the control of capillary flow in porous systems by tailoring the geometric shape of porous structures. A numerical simulation approach based on finite element method is also employed to validate the theoretical prediction. A basic capillary component with a tunable velocity gradient is designed according to the proposed framework. By using the basic component, two functional capillary elements, namely, (i) flow accelerator and (ii) flow resistor, are demonstrated. Then, multi-functional fluidic devices with controllable capillary flow are realized by assembling the designed capillary elements. All the theoretical designs are validated by numerical simulations. Finally, it is shown that the proposed concept can be extended to three-dimensional design of porous media.
Measurement of Young’s modulus of anisotropic materials using microcompression testing
Publisher: Springer Science and Business Media LLC
Date: 21-02-2012
DOI: 10.1557/JMR.2012.18
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