Researching the moving speed of particles in a drum is helpful to optimal design rotating device. In this paper, average mixing velocity flake with different shapes an elliptical studied. detail, systems rectangular, triangular, and circular are studied; rollers eccentricities periodic variation characteristics particle system at 15 rpm 45 compared analyzed; curves velocity, peak fitting curve ...

Laser wakefield accelerators can produce electric fields of order 10–100 GV/m, suitable for acceleration of electrons to relativistic energies. The wakefields are excited by a relativistically intense laser pulse propagating through a plasma and have a phase velocity determined by the group velocity of the light pulse. Two important effects that can limit the acceleration distance and hence the...

A field experiment was conducted to quantify settling velocities, aggregate states, and flocculation within a hopper dredge plume. Particular interest was in determining the abundance of dense, bed aggregates suspended from the consolidated bed during dredging. A suspended sediment plume from the hopper dredge Essayons was sampled for a period of 90 min after dredging. Settling velocities and s...

The effective equation describing the transport of passive tracers in nonsolenoidal velocity fields is determined, assuming that the velocity field U(r,t) is a function of both position r and time t, albeit remaining locally random. Assuming a strong separation of scales and applying the method of homogenization, we find a Fickian constitutive relation for the coarse-grained particle flux, as t...

A total of 50 healthy volunteers aged between 18 and 54 years underwent phase-contrast cine MRI to assess cerebrospinal fluid flow characteristics in different regions of the vertebral canal. The results revealed that the cerebrospinal fluid peak flow velocity and peak flow rate in the systolic phase were significantly greater than those in the diastolic phase at the same level in the subarachn...

Received 10.01.2010 Accepted 6.04.2010 Med Ultrason 2010, Vol. 12, No 2, 110-113 Address for correspondence: Syed Amir Gilani Faculty of Radiological Sciences and Medical Imaging. Alzaiem Alazhari University, Khartoum, Sudan. Phone; 00249-912174236 Email; [email protected] Abstract Objective: To evaluate the ductus venosus hemodynamic parameters in 31 – 40 weeks gestation normal fetus in the...

This paper addresses the dam-break problem for particle suspensions, that is, the flow of a finite volume of suspension released suddenly down an inclined flume. We were concerned with concentrated suspensions made up of neutrally buoyant non-colloidal particles within a Newtonian fluid. Experiments were conducted over wide ranges of slope, concentration and mass. The major contributions of our...

To solve the problem that the parameters in grey neural network (GNN) are difficult to determine, the improved Particle Swarm Optimization (IPSO) algorithm is employed to search the optimums by the introduction of a threshold of velocity. When the particle velocity is less than the threshold, an accelerated momentum is applied on the particle to reinitialize the particle velocity and position. ...

Particle image velocimetry and a 3D hard sphere discrete particle model were applied to determine particle velocity profiles in the plane around a spout in a spoutfluid bed for various initial bed heights, spout and background fluidization velocities. Comparison between experimental and numerical results revealed that the particle velocities are underestimated by particle image velocimetry, whi...

Based on a detailed experimental investigation in an aspect-ratio-4 rectangular cell in the range 3.7 x 10(7)<or=Ra<or=3.7 x 10(9), we present evidence of possible scenarios of the long-term dynamics of large-scale circulations (LSC) in bounded large-aspect-ratio turbulent Rayleigh-Bénard convection. Karhunen-Loève analysis of instantaneous velocity fields from long-time particle image velocime...