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Design And Validation Of An Electro-Hydraulic Pressure-Control Valve And Closed-Loop Controller, Jerry Boza
Design And Validation Of An Electro-Hydraulic Pressure-Control Valve And Closed-Loop Controller, Jerry Boza
Dissertations
Electro-hydraulic pressure-control valves are used in many applications, such as manufacturing equipment, agricultural machinery, and aircrafts to name a few. They are often used to actuate hydraulic clutches, such as those found in power shift transmissions. A traditional pressure-control valve with open-loop control algorithm is typically used in clutch applications. This scheme often results in inconsistent or undesirable system behavior due to the nature of open-loop control as well as the nonlinear system dynamics and uncertainties.
In this research two new electro-hydraulic pressure-control valves were designed in order to decouple the valve and control port (hydraulic) dynamics. This was achieved …
Migration Of An Intruder Particle In A Boundary Driven Shear Flow, Jian Liu
Migration Of An Intruder Particle In A Boundary Driven Shear Flow, Jian Liu
Dissertations
This study reports on three-dimensional, discrete element simulations of a single large spherical intruder in a Couette shear flow composed of uniform sized particles. The simulation results are useful in providing a numerical reproduction of the experiments for size segregation and mixing. This in turn has a major importance in many industries which are concerned with handling of particles and powders, such as pharmaceutical manufacturing, agriculture, chemical and mineral processing.
Discrete element simulations are carried out using the "soft sphere" model of Walton, et. al., which provides a method for obtaining the information at a macroscopic level from multi-body collisions …