Study on Charge Oscillation-Induced Low-Frequency Electric Field
Electric field induced by charge oscillation has been investigated by simulation of the electric field distribution using the finite-difference frequency-domain method. In addition, the electric field was induced by spatial oscillation of a sample to which a DC voltage was applied. The simulation and evaluation of the electric field verified that the efficiency for inducing the electric field has a proportional relationship with the amplitude displacement of a charged object, and detecting the electric field from the top to the side of the object is possible. Keywords—static electricity; charge oscillation; electric field; low frequency
The desing of simple instruments for measurement of charge on insulating surfaces
Abstract The principal design considerations for two distinct types of charge sensing instrument are outlined. The first instrument reviewed is the electrostatic field mill (generating voltmeter) which measures the resultant field due to the charge on a surface area typically of a few square centimeters. The second instrument discussed is the screened potential probe which can be scanned over a sample surface to provide an indication of charge magnitude and spatial distribution. It is shown that the required operating criteria for these instruments can easily be satisfied using solid-state devices in essentially simple circuits.
A capacitor model to interpret the electric behaviour of fluidized beds. Influence of apparatus geometry
Abstract This work provides a model to know the degree of electrification in fluidized beds on the basis of voltage measurements between an electric probe and a metallic distributor. The model is based on the similarity of behaviour between the probe-bed-distributor system and a capacitor. The influence of three variables related to apparatus geometry—height of probe, column diameter and height of bed—has been studied In an air fluidized bed of glass beads. The results show that the degree of bed electrification is not influenced by the column diameter; the effect of bed height depends on the quality of fluidization: with a bubbling bed the degree of electrification increases with bed height whereas the opposite effect is observed with a slugging bed. Additional fixed bed experiments make clear that the rate of charge dissipation grows for increasing values of bed height and column diameter, and for decreasing values of probe height.