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This paper presents the numerical analysis and experiments on the electromechanical behavior of conducting wired-shape particles. We investigate the effects of particle ending profiles and orientation on the initial motion. The boundary element method is used to analyze the electric field, forces, and torques on the particles. The calculated liftoff electric field is smaller than the estimated value based on a model of infinitely long cylinder, and slightly decreases for a particle with a sharp end when the sharp tip is separated from the electrode. The measured liftoff electric field agrees with the tendency obtained from the numerical analysis. Particles mostly began the motion at either end. When the sharp tip was separated from the electrode, the initial motion almost exclusively took place at the sharp end. On the other hand, the probability was slightly higher for the motion at the rounded end when the sharp tip was close to the electrode. The numerical calculation clarifies that the electrostatic and gravitational torques contribute to such liftoff behavior. [ABSTRACT FROM AUTHOR]

This paper presents a numerical method to simulate the particle trajectory in the head–disk interface (HDI). The simulator solves the reduced Navier–Stokes equation with the second-slip boundary conditions to get the air velocity distribution, then solves the motion equations of particles and obtains the trajectories of the particles in the HDI using the binary Lagrange interpolation and the fourth-order Runge–Kutta method. The calculated trajectories of particles follow well with the air streamlines in the recessed regions. The particle density, diameter, and initial entering velocity have different effects on particle movement. Furthermore, particle velocity behaviors in the recessed regions are investigated for the first time. The particle is accelerated or decelerated by the action of the drag force and becomes close to the velocity of local air flow. Such effects are more obvious for small particles than large particles. The particle velocity becomes very small when it is close to the leading edge of the trailing pad. The numerical results also show that the particle goes up when it crosses the transition regions, and the particle moves upward more sharply with higher initial entrance height due to the larger vertical velocity of the local air flow. [ABSTRACT FROM AUTHOR]

This paper describes the design, the fabrication, and the characterization of an interdigitated 3-D silicon (Si) ring microelectrodes for dielectrophoretic (DEP) manipulation of particles. The 3-D microelectrodes are derived from a high-aspect-ratio comb structure etched in a doped single crystal Si on an insulating dielectric (silicon-on-insulator). Fingers of the comb are evolved into ring microelectrodes once perforated with a linear array of well-defined round lateral constrictions. This is achieved by the segmented finger layout and the Si dry release strategy borrowed from inertial microelectromechanical systems. The fingers and their interspaces are sealed with a cover layer forming a microfluidic flow chamber surrounded by 3-D microelectrodes and accessible via single inlet/outlet. The functionality of the device has been verified on 2- and 10-\mu \m polystyrene microspheres in pressure-driven flow through the ring microelectrodes at 3.3 \mu\L/min effectively focusing them into streams or trapping them around the fingers at moderate voltage levels (20–40 Vpp). \hfill[2012-0209] [ABSTRACT FROM PUBLISHER]

The force acting upon a free metallic particle in an alternating electric field will determine its motion and ultimately allow for the estimation of the risk imposed due to dielectric failure of the high voltage equipment. Existing models approximate the force with Lorentz' law and consider the charge resting upon the surface as being lumped into a point charge at the center of the particle during its motion. The model proposed in this paper demonstrates a time stepped electrostatic Finite Element Method to calculate these forces, therefore taking into account the charge distribution upon the surface of the particle. The use of this model is seen to have a significant effect upon the motion of the particle under certain conditions. [ABSTRACT FROM AUTHOR]