Effect of an electric field on an intermittent granular flow

Granular gravity driven flows of glass beads have been observed in a silo with a flat bottom. A DC high electric field has been applied perpendicularly to the silo to tune the cohesion. The outlet mass flow has been measured. An image subtraction technique has been applied to visualize the flow geometry and a spatiotemporal analysis of the flow dynamics has been performed. The outlet mass flow is independent of voltage, but a transition from funnel flow to rathole flow is observed. This transition is of probabilistic nature and an intermediate situation exists between the funnel and the rathole situations. At a given voltage, two kinds of flow dynamics can occur : a continuous flow or an intermittent flow. The electric field increases the probability to observe an intermittent flow.Comment: Accepted for publication in PRE on Apr 9, 201

Development and Application of Quantitative Methodologies for the Characterization of Passive Hearing Protection Devices

The sense of hearing enables communication and the ability to maintain balance and orientation. Protecting the auditory system against dangerous acoustical conditions permits us preserving a healthy and joyful life. The main goal of this project is to develop and apply analytical, computational, and experimental methods to investigate the effectiveness of current passive hearing protection devices and to understand the correlation between microstructure, macrostructure, and performance. It is expected that the results obtained in this project will enable future engineers to design and realize innovative mechanisms that incorporate advanced microstructures, geometries, and composite materials to more effectively protect the human ear