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Various experimental and numerical studies have been carried out to study the velocity profiles of the particles inside horizontal rotating drums, but little emphasis has been laid on inclined rotating drums, though these drums are extensively used in granular process industries. In this study, velocity profiles of the particles in a rotating drum with 0o, 5o, 10o, and 15o inclinations have been studied by using the discrete element method. It was found that at the locations of the drum with the volumetric fill in the range of 0.2 0.8, the inclined rotating drum has a similar variation of velocity with the radial height to the horizontal rotating drum. However, the variation of the average particle velocity along the length of the drum differs for horizontal and inclined drums. Furthermore, for the inclined rotating drum, the average velocity increases with the increase in the volumetric fill.

Fluid flowing through packed beds of multi-sized spheres is studied by a parallel lattice-Boltzmann (LB) model. The packed beds are generated by means of the discrete element method. First, the LB model is used to study the effects of size ratio and volume fraction on the fluid flow and quantify the drag forces on binary mixtures of particles. Typical flow behaviours are identified in relation to pore geometries. The results suggest that the polydispersity in particle size enhances local structure heterogeneity and flow non-uniformity, resulting in distributed fluid-particle interaction forces. Then, based on the simulated data, a new equation is formulated to calculate the mean individual drag force. The equation is extended to multicomponent mixtures of particles. The results show that the new equation is more accurate and reliable than those in the literature, and can be generally used in the modelling of particle-fluid flows. [ABSTRACT FROM AUTHOR]

Thispaper presents a numerical study of particle flow and sieving behavioron a vibrating screen. The particle flow is modeled by means of discreteelement method (DEM) at a particle scale. The DEM model is first verifiedby the good agreement between the numerical and experimental resultsin terms of the distribution of percentage passing of different sizedparticles along the screen deck. The effects of variables such asincline angle, vibrating frequency, and amplitude are then studiedwith special reference to the overall screen efficiency and distributionof the passing rates for different sized particles. The performanceof such a screening process is shown to be related to particle flowon the screen such as the structure of particle bed, particle velocities,and particle–particle and particle–deck interactions.In particular, it is demonstrated that the sieving performance atthe process equipment scale can be linked with the particle–deckcollisions obtained from the DEM simulations, facilitated by the well-establishedprobability theory. Finally, based on the simulation data, a mathematicalmodel is proposed to link the particle–deck collisions withthe three variables considered. The mathematical model can satisfactorilyestimate the process performance in terms of weight percentage passings,particularly when the effect of particle–particle interactionsis not significant. [ABSTRACT FROM AUTHOR]

This article presents a numerical study on the settling of uniform spheres in liquids by means of the discrete element method. The effects of particle and liquid properties, such as particle size, Hamaker constant, liquid density, and viscosity, on the formation of packed beds or cakes were studied in terms of packing fraction, radial distribution function (RDF), and coordination number (CN). The results showed that the packing fraction of a cake increases with increasing particle size but decreases with increasing the Hamaker constant, liquid density, and viscosity. RDF and CN also change correspondingly: packings with lower packing fraction generally have RDFs with fewer peaks and smaller mean CNs. A good correlation between packing fraction and other structural properties was identified. The analysis of the particle-particle and liquid-particle interactions showed that the packing properties are mainly affected by the ratio of the interparticle cohesion to the effective gravity of particles. The previously proposed equation linking packing fraction with the interparticle forces has been extended to incorporate the impact-induced pressure force in a settling process. Based on the modified equation, the effects of key variables on the relationship between packing fraction and particle size were re-examined for general application. © 2011 American Institute of Chemical Engineers AIChE J, 2012. [ABSTRACT FROM AUTHOR]

The a decay rate of 210Po was measured in a film sample (210Po @Bi2O3) and a slice sample (210Po @Bi metal), respectively. The former was used as a reference sample. The half-lives of 210Po @Bi2O3 and 210Po @Bi metal environments were observed to be (138.40 ± 0.21 d) and (138.87 ± 0.87 d) at room temperature, respectively. It was found that the half-life of 210Po is consistent with international recommendations within the uncertainty 0Po between film sample (210Po ©Bi2O3) and limits, and we did not find any deviation of the a decay rate of slice sample (210Po @Bi metal). [ABSTRACT FROM AUTHOR]

The 13C(9Be,8Li)14N angular distribution was measured with a 9Be beam of 40 MeV. The proton spectroscopic factor of the 9Be ground state was extracted to be 0.73 ± 0.15 by the normalization of the calculated differential cross sections with the distorted-wave Born approximation (DWBA) to the experimental data. The spectroscopic factor was compared to existing theoretical and experimental values. [ABSTRACT FROM AUTHOR]

We present a physical and numerical study of the settling of uniform spheres in liquids and show that interparticle forces play a critical role in forming the so-called random loose packing (RLP). Different packing conditions give different interparticle forces and, hence, different RLP. Two types of interparticle forces are identified: process dependent and process independent. The van der Waals force, as the major cohesive force in the present study, plays a critical role in effecting the process-dependent forces such as drag and lift forces. An equation is formulated to describe the relationship between the macroscopic packing fraction and microscopic interparticle forces in a packing. We argue there is no lowest packing fraction for a mechanically stable RLP; hence, the packing fractions of RLP can range from 0 to 0.64 depending on the cohesive and frictional conditions between particles.