Frictionless conveying of frictional materials
Following a brief review of the technology and previous analyses of vibratory conveying of granular materials, a general solution is derived for a well-known rigid-slab model of slide-conveying in open and closed conduits, with Coulomb friction at the walls. The solution is applied to periodic rectangular-wave and sinusoidal forcing, and it is shown that the rectangular-wave forcing admits ideal cycles in which the kinematically optimal transport is also thermodynamically optimal, in the sense that no energy is dissipated by sliding friction.
Theoretical and experimental study of the transport of granular materials by inclined vibratory conveyors
A theoretical and experimental study was made of the conveying speed with which granular materials are transported by vibratory conveyors. The basic assumption made is that the layer of granular material can be considered as a point mass. The theory incorporates rest, slide, and flight phases of the material. Although the emphasis of this study is on the effect of the inclination (and declination) of the conveyor on the conveying speed, the effects of throw number, friction coefficient and vibration angle on the conveying speed are also shown. A useful method is presented for measuring the coefficient of friction between granular material and vibratory conveyor. Experiments were performed in order to verify the point mass theory. The agreement between theory and experiment is fairly good for slide conveyors but for throw conveyors larger deviations are observed. Some possibilities for improvement to the theory are briefly investigated.
Ground Fault Protection for Electric Utility Generating Station Medium Voltage Auxiliary Power Systems
Most generating station designs have medium voltage auxiliary power systems with low resistance grounded neutrals.1 In order to provide even higher reliability, the auxiliary power distribution system configurations supply increasingly redundant process equipment.