If a contact of two purely elastic bodies with no sliding (infinite coefficient of friction) is subjected to superimposed oscillations in the normal and tangential directions, then a specific damping appears, that is not dependent on friction or dissipation in the material. We call this effect "relaxation damping". The rate of energy dissipation due to relaxation damping is calculated in a clos...

This letter proposes an analytical approach to formulate the power system oscillation frequency under a large disturbance. A fact is revealed that the oscillation frequency is only the function of the oscillation amplitude when the system’s model and operating condition are fixed. Case studies also show that this function is damping-insensitive and could be applied to an inter-area model of a m...

The linearly damped oscillator equation is considered with the damping term generalized to a Caputo fractional derivative. The order of the derivative being considered is 0 ≤ v ≤ 1. At the lower end v 0 the equation represents an undamped oscillator and at the upper end v 1 the ordinary linearly damped oscillator equation is recovered. A solution is found analytically, and a comparison with the...

We have studied the linear dispersion relation for Langmuir waves in plasmas of very high density, based on Dirac–Heisenberg–Wigner formalism. The vacuum contribution to physical observables leads ultraviolet divergences, which are removed by a charge renormalization. remaining is small and agreement with previously derived expressions time-dependent polarization. main new feature theory dampin...

Stellar oscillation under the combined influences of incident gravitational wave and radiation loss is studied in a simple toy model. The star is approximated as a uniform density ellipsoid in the Newtonian gravity including radiation damping through quadrupole formula. The time evolution of the oscillation is significantly controlled by the incident wave amplitude h, frequency ν and damping ti...

A novel digital oscillator topology for microelectromechanical systems (MEMS) based on bandpass sigma–delta modulation is presented. Short pulses of force of the same amplitude maintain the oscillation and the associated bit-stream output serves to know the oscillation frequency which, for low mechanical losses, is very close to the natural frequency of the MEMS resonator. Position-sensing requ...

Plasmon resonance in nanostructured metals is in essence collective oscillation of free electrons, which is driven by optical electric fields and oscillates at nearly the same frequency as the excitation photons. This is the basic physics for the currently extensively interested topics in optical metamaterials, optical switching, and logic optical "circuits" with potential applications in optic...

To enhance the inertial response and damping capability during transient events this paper investigates an improved active power control for variable speed wind turbines. The optimized power point tracking (OPPT) controller, which swings the turbine operating point from the maximum power point tracking (MPPT) curve to the virtual inertia control (VIC) curves by the frequency deviation, is propo...

Pulse Width modulated based Series Compensator (PWMSC), a newly FACTS device, can modulate the impedance of a transmission line through the variation of the duty cycle of a train of pulses with fixed frequency, resulting in improvement of system performance. In this study, a current injection model of PWMSC is proposed and incorporated in the transmission system model. The purpose of the work r...