Collective phenomena in granular and atmospheric electrification

Abstract

This repository contains data from the Granular Electrification Experiment in the University of Maryland Nonlinear Dynamics Lab. The experiment consists of a cylindrical cell with aluminum plates on the top and bottom. The cell is filled with granular particles and shaken vertically for several cycles. The vertical position of the cell and the electric potential between the top and bottom endplates of the cell are acquired. The data in this repository is from experiments in which the cylindrical cell is filled with only one type of particle. One exception uses two types of particles, pointed out below. A particle type is comprised of its material, form (spheres or powder), and size range. The acceleration timeseries of the shaking is approximately a square wave with amplitude a, meaning that the vertical position is approximately a sequence of parabolas of alternating concavity. The stroke-length of the oscillation is 10.0 cm. The shaking strength is quantified as a/g where g is the free fall acceleration due to gravity on Earth. The amount of particles is quantified by the dimensionless parameter lambda = 2 N_p d^2 / (3 D^2) where N_p is the number of particles, d is the particle diameter (or effective diameter), and D is the diameter of the cell.