The Experts below are selected from a list of 3138 Experts worldwide ranked by ideXlab platform
Martin J Rhodes - One of the best experts on this subject based on the ideXlab platform.
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effect of Interparticle Force on mixing and segregation of dry granular materials
Physical Review E, 2004Co-Authors: S Hutton, Martin J Rhodes, Adam J Forsyth, Charles F OsborneAbstract:In this paper, the effects of Interparticle Force on mixing, segregation, and stratification in dry granular materials are investigated. Avalanche segregation, stratification and also segregation in rotating drums are examined. A series of binary mixtures of granular materials is prepared which consists of spherical iron particles and a nonmagnetic material. By placing each mixture in a magnetic field, the induced magnetic Interparticle Force could be altered and the effects on particle segregation observed. Using this technique, the effects of altering Interparticle Force on both avalanche and radial segregation are examined. It is found that altering Interparticle Force could induce mixed materials to segregate and also induce segregating granular materials to mix. We also report a complete reversal of segregation and stratification as Interparticle Force was increased. These results have important implications for the mixing of cohesive powders.
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further study of the role of Interparticle Force in determining fluidization characteristics
Chemeca: Australasian Conference on Chemical Engineering 2004, 2004Co-Authors: Jai Kant Pandit, Xiao Shan Shan Wang, Martin J RhodesAbstract:Here we report on a study based on the discrete element method simulation of fluidized beds of spherical particles, which, according to their size and density, belong to Group B and Group A of Geldart's classification. Simulations have been performed both in the absence of any Interparticle cohesive Force and with an imposed cohesive Force equivalent in magnitude to several times the single particle buoyant weight. Homogeneous fluidization is observed for a significant range of gas velocity and minimum bubbling velocity is found to be greater than minimum fluidization velocity, even when there is no Interparticle Force. This is evidence of true Group A behaviour in the absence of Interparticle cohesive Force. Smaller particles, further from the boundary between Groups A and B, showed more expansion before the start of bubbling and a higher ratio of minimum bubbling velocity to minimum fluidization velocity. Unlike in the bed of Group B powders, imposing artificial Interparticle Force of moderate magnitude does not change the bed characteristics significantly for the bed of Group A powders.
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study of fluidization behaviour in presence of externally imposed Interparticle Force
Chemeca 2003: Products and Processes for the 21st Century : Proceedings of the 31st Australasian Chemical Engineering Conference, 2003Co-Authors: Jai Kant Pandit, Xiao Shan Wang, Martin J RhodesAbstract:Fluidization behaviour of iron particles, in the presence of an externally imposed Interparticle cohesive Force, was studied in a cylindrical bed. To create the Interparticle Force between the bed particles, an external magnetic field was imposed on the bed. The influence of the magnitude of Interparticle cohesive Force on the minimum fluidization velocity, minimum bubbling velocity and bed expansion behaviour was studied. It was observed that the minimum fluidization velocity was insensitive to changes of Interparticle Force, whilst the minimum bubbling velocity increased with increasing Interparticle Force. The minimum fluidization velocity was found to be a function of the initial bed voidage, whilst the minimum bubbling velocity was observed to be independent of the initial bed voidage. The degree of bed expansion before bubbling was found to vary with Interparticle Force. The exponent of the Richardson-Zaki form of equation was found to be insensitive to Interparticle Force for a given fluid-particle system.
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effect of cohesive Interparticle Force on the flow characteristics of granular material
Powder Technology, 2002Co-Authors: Adam J Forsyth, S Hutton, Martin J RhodesAbstract:Abstract The transition from free-flowing to “stick–slip” or cohesive flow in particulate solids was studied using two systems: glass spheres in humidity-controlled air and iron spheres within a magnetic field. The flow characteristics of glass spheres in the range 25–3000 μm were studied as a function of relative humidity (RH) using a rotating inclined cup apparatus. It was found that there is a critical relative humidity at which the spheres undergo the transition from free-flowing to stick–slip behaviour, and this critical humidity increases with increasing particle size. Atomic Force Microscope (AFM) measurements suggest that this transition is due to the system achieving a certain critical level of cohesive Interparticle Force and not due to an abrupt rise in this Force. Similar experiments were performed using iron spheres in a magnetic field, thus allowing the Interparticle (magnetic) cohesive Force to be controlled. The results confirmed the above finding and suggested that the transition from free-flowing to stick–slip behaviour occurs at a critical ratio of Interparticle Force to particle weight.
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effects of Interparticle Force on the packing of spherical granular material
Physical Review Letters, 2001Co-Authors: Adam J Forsyth, S Hutton, Charles F Osborne, Martin J RhodesAbstract:We present a study of the influence of Interparticle cohesive Forces on the packing of spheres. This is achieved by changing the external magnetic field on iron spheres in the millimeter size range. The Force of cohesion between two spheres is measured by opposing magnetic and gravitational Force. The void fraction of the bed resulting from many spheres being poured into a container at a given magnetic field is measured. The void fraction of the packed spheres as a function of Interparticle Force is thus established. We find that the void fraction is determined only by the ratio of Interparticle Force to particle weight, regardless of particle size. This is shown to be a universal effect, not limited to magnetic systems.
Yasuyuki Kimura - One of the best experts on this subject based on the ideXlab platform.
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measurement of Interparticle Force between nematic colloids
Proceedings of SPIE, 2014Co-Authors: Yasuyuki Kimura, Kuniyoshi IzakiAbstract:Micro-sized colloidal particles dispersed in nematic liquid crystal become topological defects in uniform orientation of liquid crystal. Since they increase the elastic energy of the liquid crystal, a long-ranged anisotropic interaction is induced between them. In this study, we reported the Interparticle Force measured by various methods utilizing optical tweezers. The Interparticle Force depends on the type of particle-defect pair and its dependence on the Interparticle distance is in agreement with the theoretical prediction using electrostatic analogy. This anisotropic Force enables us to construct characteristic clusters, which cannot be realized in conventional water-based colloidal dispersions. We made some novel colloidal assemblies in two dimensions by utilizing optical tweezers to demonstrate the availability of the anisotropic Force in nematic colloids
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Interparticle Force between different types of nematic colloids
Physical Review E, 2013Co-Authors: Kuniyoshi Izaki, Yasuyuki KimuraAbstract:We have studied the Interparticle Force between colloidal particles with three different types of defects in nematic liquid crystal by dual-beam optical tweezers. The Force between a dipole (D)- and a Saturn-ring (S)-type particle at large Interparticle distance R is proportional to R(-4.95±0.05). The Force between a D- and a planar (P)-type particle and that between an S- and a P-type particle are, respectively, proportional to R(-5.04±0.08) and R(-5.78±0.13). The observed dependence of the Interparticle Force on R at large R is in agreement with that predicted by electrostatic analogy. The topological quadrupole moments for S and P particles are evaluated from experimental data. We have also studied the Force curves in oblique arrangement against the far-field director for respective pairs. The experimental Force curves at large R quantitatively agree with those predicted by electrostatic analogy, but they always become attractive at small R due to the reorientation and deformation of defects. The Force profiles for the S-P pair are also compared with those obtained by the recent numerical simulation.
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Interparticle Force in nematic colloids comparison between experiment and theory
Physical Review E, 2011Co-Authors: Takahiro Kishita, Noboru Kondo, Kenji Takahashi, Masatoshi Ichikawa, Jun Ichi Fukuda, Yasuyuki KimuraAbstract:We have studied the Interparticle Force between two colloidal particles in a nematic liquid crystal experimentally and theoretically. The Force $F$ was directly measured using dual-beam optical tweezers and was numerically calculated from the equilibrium tensor field around the particles. The dependence of $F$ on the center-to-center distance $R$ between the particles was studied not only for equal-sized particles but also for different-sized ones in various kinds of configurations and arrangements. The magnitude of $F$ between different-sized particles in the dipole configuration depends on their relative arrangement. Both experimental and theoretical Force curves are found to be in good agreement with each other. At large $R$, they also make agreement with those predicted by an electrostatic analogy of nematic field.
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temperature and confinement effect on Interparticle Force in nematic colloids
Molecular Crystals and Liquid Crystals, 2011Co-Authors: Noboru Kondo, Yasutaka Iwashita, Yasuyuki KimuraAbstract:We experimentally studied the Interparticle Force between two colloidal particles with point defects in a nematic liquid crystal. The Force F at various temperatures was measured using optical tweezers and with a free release method. The effective elastic constant was evaluated from F using electrostatic analogy of nematic field. At respective temperatures, that is in good agreement with the splay constant obtained by dielectric measurement. The dependence of F on cell thicknesses was also studied in a wedge-type cell. In a thinner cell, the magnitude of F becomes smaller, and F becomes short-ranged.
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dependence of Interparticle Force on temperature and cell thickness in nematic colloids
Physical Review E, 2010Co-Authors: Noboru Kondo, Yasutaka Iwashita, Yasuyuki KimuraAbstract:We have experimentally studied the Interparticle Force between two particles accompanied by hyperbolic hedgehog defects in a nematic liquid crystal. The Force $F$ was measured with dual-beam optical tweezers at various temperatures and in cells with various thicknesses. In a thick cell, the dependence of $F$ on the Interparticle distance $R$ obtained at different temperatures can be scaled to a universal curve of $F\ensuremath{\propto}{R}^{\ensuremath{-}4}$ for $Rg3a$, where $a$ is the radius of a particle. The effective elastic constant evaluated from $F$ is found to be in good agreement with splay constant of the nematic liquid crystal. In a thin cell, the magnitude of $F$ decreases and the dependence of $F$ on $R$ becomes short-ranged as the thickness of a cell, $L$, decreases. The reduced Force curves, $F{L}^{4}$ against $R/L$, at different $L$ are found to be scaled to a single theoretical curve which has been proposed recently.
Jones T K Wan - One of the best experts on this subject based on the ideXlab platform.
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Interparticle Force in polydisperse electrorheological fluids beyond the dipole approximation
Computer Physics Communications, 2001Co-Authors: Y L Siu, Jones T K WanAbstract:We have developed a multiple image method to compute the Interparticle Force for a polydisperse electrorheological (ER) fluid. We apply the formalism to a pair of dielectric spheres of different dielectric constants and calculate the Force as a function of the separation. The results show that the point-dipole (PD) approximation errs considerably because many-body and multipolar interactions are ignored. The PD approximation becomes even worse when the dielectric contrast between the particles and the host medium is large. From the results, we show that the dipole-induced-dipole (DID) model yields very good agreements with the multiple image results for a wide range of dielectric contrasts and polydispersity. The DID model accounts for multipolar interaction partially and is simple to use in computer simulation of polydisperse ER fluids.
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dynamic electrorheological effects and Interparticle Force between a pair of rotating spheres
Physical Review E, 2000Co-Authors: Jones T K WanAbstract:We consider a two-particle system in which a particle is held fixed, and the other one rotates around the axis perpendicular to the line joining the particles' centers. The rotating particle leads to a displacement of its polarization charge on the surface. Our results show that the rotational motion of the particles generally reduces the Force between the particles. The dependence of Interparticle Force on the angular velocity of rotation will be discussed.
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Interparticle Force in polydisperse electrorheological fluids
Computer Physics Communications, 2000Co-Authors: Jones T K WanAbstract:We have developed a multiple image method and an integral equation approach to compute the Interparticle Force for a polydisperse electrorheological (ER) fluid in which the suspending particles can have various sizes. As an illustration, we apply the formalism to a pair of dielectric spheres of different radii and calculate the Force as a function of the separation. The results show that the point-dipole approximation errs considerably because many-body and multipolar interactions are ignored. The approximation becomes even worse when the particle sizes differ too much in polydisperse ER fluids. From the results, a dipole-induced-dipole (DID) model is proposed for computer simulation. The DID model accounts for many-body and multipolar interactions partially, but is simpler than the coupled-dipole model because a self-consistent solution is not needed.
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Interparticle Force in nonlinear electrorheological fluids
International Journal of Modern Physics B, 2000Co-Authors: Jones T K WanAbstract:The applied electric field used in most electrorheological (ER) experiments is usually quite high, and nonlinear ER effects have been measured recently. In this work, a self-consistent formalism has been employed to compute the Interparticle Force for a nonlinear ER fluid in an attempt to investigate the effect of a nonlinear characteristics on the particle interactions.
Kian Meng Lim - One of the best experts on this subject based on the ideXlab platform.
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Interparticle Force and torque on rigid spheroidal particles in acoustophoresis
Wave Motion, 2018Co-Authors: Felix Bob Wijaya, Shahrokh Sepehrirahnama, Kian Meng LimAbstract:Abstract The movement of the particles in acoustophoresis is driven by the acoustic radiation Force acting on the particles. Particles with positive contrast factor tend to agglomerate once they are pushed by the primary Force to the vicinity of the pressure node. The main driving Force of this agglomeration is the Interparticle Force. In this study, the boundary element method is used to calculate the Interparticle Force and torque acting on a pair of spheroidal particles. The numerical results show that the Interparticle Force is dominant over the primary Force when the spheroids are near the pressure nodal plane, similar to the case of two spheres. On contrary, the Interparticle torque is insignificant compared to the primary torque, even when the spheroids are close to each other. The results also provide a preliminary study about how biological cells, which are mostly not spherical in shape, agglomerate and orient themselves in the vicinity of the pressure node.
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experimental measurement of Interparticle acoustic radiation Force in the rayleigh limit
Physical Review E, 2018Co-Authors: Abhishek Ray Mohapatra, Shahrokh Sepehrirahnama, Kian Meng LimAbstract:Acoustophoresis is a form of contact-free particle manipulation in microfluidic devices. The precision of manipulation can be enhanced with better understanding of the acoustic radiation Force. In this paper we present the measurements of Interparticle radiation Force between a pair of polystyrene beads in the Rayleigh limit. The study is conducted for three different sizes of beads and the experimental results are of the same order of magnitude when compared with theoretical predictions. However, the experimental values are larger than the theoretical values. The trend of a decrease in the magnitude of the Interparticle radiation Force with decreasing particle size and increasing center-to-center distance between the particles is also observed experimentally. The experiments are conducted in the specific scenario where the pair of beads are in close proximity, but not in contact with each other, and the beads are approaching the pressure nodal plane with the center-to-center line aligned perpendicular to the incident wave. This scenario minimizes the presence of the primary radiation Force, allowing accurate measurement of the Interparticle Force. The attractive nature of the Interparticle Force is observed, consistent with theoretical predictions.
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effects of viscosity and acoustic streaming on the Interparticle radiation Force between rigid spheres in a standing wave
Physical Review E, 2016Co-Authors: Shahrokh Sepehrirahnama, Fook Siong Chau, Kian Meng LimAbstract:The total acoustic radiation Force acting on interacting spheres in a viscous fluid consists of the primary and secondary Forces. The primary Force pushes rigid spheres to the pressure node due to the incident standing wave. The secondary Force is the Interparticle Force caused by the interaction between spheres in the standing wave. In this study, an algorithm based on the multipole series expansion and Stokeslet method is proposed for calculating the primary and secondary radiation Forces acting on a pair of spheres in a viscous fluid. It is concluded that the acoustical interaction between a pair of spheres is considerably stronger in a viscous fluid compared to the inviscid case due to the streaming effects in the viscous fluid. For spheres located far from each other, the interaction becomes considerably weak; thus, the spheres move mainly due to the primary radiation Force.
Adam J Forsyth - One of the best experts on this subject based on the ideXlab platform.
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effect of Interparticle Force on mixing and segregation of dry granular materials
Physical Review E, 2004Co-Authors: S Hutton, Martin J Rhodes, Adam J Forsyth, Charles F OsborneAbstract:In this paper, the effects of Interparticle Force on mixing, segregation, and stratification in dry granular materials are investigated. Avalanche segregation, stratification and also segregation in rotating drums are examined. A series of binary mixtures of granular materials is prepared which consists of spherical iron particles and a nonmagnetic material. By placing each mixture in a magnetic field, the induced magnetic Interparticle Force could be altered and the effects on particle segregation observed. Using this technique, the effects of altering Interparticle Force on both avalanche and radial segregation are examined. It is found that altering Interparticle Force could induce mixed materials to segregate and also induce segregating granular materials to mix. We also report a complete reversal of segregation and stratification as Interparticle Force was increased. These results have important implications for the mixing of cohesive powders.
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effect of cohesive Interparticle Force on the flow characteristics of granular material
Powder Technology, 2002Co-Authors: Adam J Forsyth, S Hutton, Martin J RhodesAbstract:Abstract The transition from free-flowing to “stick–slip” or cohesive flow in particulate solids was studied using two systems: glass spheres in humidity-controlled air and iron spheres within a magnetic field. The flow characteristics of glass spheres in the range 25–3000 μm were studied as a function of relative humidity (RH) using a rotating inclined cup apparatus. It was found that there is a critical relative humidity at which the spheres undergo the transition from free-flowing to stick–slip behaviour, and this critical humidity increases with increasing particle size. Atomic Force Microscope (AFM) measurements suggest that this transition is due to the system achieving a certain critical level of cohesive Interparticle Force and not due to an abrupt rise in this Force. Similar experiments were performed using iron spheres in a magnetic field, thus allowing the Interparticle (magnetic) cohesive Force to be controlled. The results confirmed the above finding and suggested that the transition from free-flowing to stick–slip behaviour occurs at a critical ratio of Interparticle Force to particle weight.
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effects of Interparticle Force on the packing of spherical granular material
Physical Review Letters, 2001Co-Authors: Adam J Forsyth, S Hutton, Charles F Osborne, Martin J RhodesAbstract:We present a study of the influence of Interparticle cohesive Forces on the packing of spheres. This is achieved by changing the external magnetic field on iron spheres in the millimeter size range. The Force of cohesion between two spheres is measured by opposing magnetic and gravitational Force. The void fraction of the bed resulting from many spheres being poured into a container at a given magnetic field is measured. The void fraction of the packed spheres as a function of Interparticle Force is thus established. We find that the void fraction is determined only by the ratio of Interparticle Force to particle weight, regardless of particle size. This is shown to be a universal effect, not limited to magnetic systems.
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Effect of Applied Interparticle Force on Packing Density and the Angles of Repose in Mono-sized Spherical Granular Material: Australian Standard Research Classification (290699)
2000Co-Authors: Adam J Forsyth, Martin J Rhodes, Hutton, Charles F OsborneAbstract:The effect of Interparticle Force on packing density and both static and dynamic angles of repose are investigated. The novel feature of this work is the use of a homogenous magnetic field to induce an attractive Interparticle Force, allowing a wide range of packing densities and angles of repose to be investigated, and characterised as a function of Interparticle interaction. The voidage and the angles of repose were found to increase approximately linearly with increasing Interparticle Force.
