The applications of supported metal catalysts vary widely, from selective hydrogenation in the fine chemicals industry to the control of vehicle emissions. Yet many basic questions about the structure, activity, and durability of these catalysts remain unanswered. For example, there is still much uncertainty about the mechanism of metal particle growth, or sintering, which is a major cause of c...

We are currently studying microstructural responses to diffusion-limited coarsening in twophase materials. A mathematical solution to late-stage multiparticle diffusion in finite systems is formulated with account taken of particle-particle interactions and their microstructural correlations, or “locales”. The transition from finite system behavior to that for an infinite microstructure is esta...

Numerous investigations have been devoted towards understanding the hydrodynamics of gas jets in fluidized beds. However, most of them address the problem from  macroscopic point of view, which does not reveal the true behavior in the jet region at the single particle level. The present work aims to understand the jet behavior from a more fundamental level, i.e. the individual particle leve...

Using computer simulations, we study a two-dimensional system of sterically interacting self-mobile run-and-tumble disk-shaped particles with an underlying periodic quasi-one-dimensional asymmetric substrate, and show that a rich variety of collective active ratchet behaviors arise as a function of particle density, activity, substrate period, and the maximum force exerted by the substrate. The...

We study the dynamics of a classical particle moving in a punctured plane under the influence of a strong homogeneous magnetic field, an electrical background, and driven by a time-dependent singular flux tube through the hole. We exhibit a striking classical (de)localization effect: in the far past the trajectories are spirals around a bound center; the particle moves inward towards the flux t...

The results leading to the identification of coherent structures emerging from the background turbulence in the edge region of the reversed field pinch experiments EXTRAP-T2R and RFX are reviewed. These structures have traits of vortices in velocity field and blobs in density, and the reconstruction of their spatial structure and of their time evolution is discussed focusing on the analysis too...

-The distribution and size of large marine aggregates (>0.5 mm) photographed in situ were compared with the small-particle distribution determined from beam attenuation (660 nm) in a section across the shelf and slope of the northern Gulf of Mexico. On the shelf changes in beam attenuation matched the trends in large particle concentration. Over the slope, beam attenuation profiles resembled th...

Dust-particles charging in a low-pressure glow discharge was investigated theoretically. The dust-particle charge was found on the basis of a developed self-consistent model taking into account the nonequilibrium character of electron distribution function and the formation of an ionic coat composed of bound or trapped ions around the dust particle. The dust-particle charge, the radial distribu...

in this study, a mixed matrix polyethersulfone/iron-nickel oxide nanoparticle nanofiltration membrane was prepared by the solution casting technique. polyvinylpyrrolidone was also used as a membrane pore former in membrane fabrication. the effect of iron-nickel oxide nanoparticles concentration in the casting solution on the membrane structure and performance was investigated. scanning optical ...

The iron Kα line is perhaps the most important spectral diagnostic available in the study of accreting black holes. The line is thought to result from the reprocessing of external X-rays by the surface of the accretion disk. However, as is observed in the solar corona, illumination by energetic particles may also produce line emission. In principle, such a process may be uncorrelated with the o...