Metasurfaces formed by monopole and dipole resonators are studied theoretically. The Helmholtz or membranes vibrating on the first eigenfrequency; ones spheres springs second eigenfrequency. It is shown that acoustic properties of metasurface built-in can be described an equivalent impedance, which characterizes a normal forcing to surface, whereas this impedance not suitable for resonators, be...

Resonant temporary overvoltages during transformer energization may result in damage to the itself or surrounding equipment. These are caused by interplay between currents and grid impedance. Current practice assess risk of is classifying scenarios into potentially problematic non-problematic based on magnitude impedance at frequencies coinciding with harmonic frequencies. At moment, this appro...

The harmonic response and modal shapes of axially-symmetrical piezoceramic cylinders (tubes) polarised through the wall thickness have been predicted by finite element methods and determined experimentally. Analysis of ceramic cylinders has concentrated on the effects of the variation of diameter to thickness (d/t) ratios, and change in cylinder length (l). Investigation has taken into account ...

Previous work has attempted to find satisfactory methods for the allocation of harmonic current emission MV subsystems containing long feeders. It has been proposed that best use of the network's harmonic absorption capacity is made if the allocated current varies with the inverse square root of the harmonic impedance at the point of connection. It has been shown that an exact solution followin...

An innovatory on–line method of power system frequency estimation and voltage/current signals resampling is presented. The method is designed to increase the accuracy of power system equivalent harmonic impedance estimation using simple DAQ systems. Estimation of instantaneous frequency uses 5–th degree polynomial interpolation of filtered signal zero crossings time positions. Final resampling ...

Magnetic resonance electrical impedance tomography (MREIT) is a new medical imaging modality visualizing static conductivity images of electrically conducting subjects. Recently, MREIT has rapidly progressed in its theory, algorithm, and experiment technique and now reached to the stage of in vivo animal experiments. In this paper, we present a software, named CoReHA 2.0 standing for the second...

In an oscillatory flow, the resistance to flow, more appropriately defined as the impedance to flow, is a function of oscillating frequency, which refers to the harmonic composition of the driving pressure wave. Flow in an elastic tube may be resisted in numerous ways such as the fluid viscosity, fluid inertia and tube elasticity. The concept of impedance arises in the dynamics of the Resistanc...

Increasing use of variable speed drives in industry causes harmonic proliferation in industrial power distribution supply system. Harmonic currents generated by the variable speed drives interact with power system impedance to give rise to harmonic voltage distortion. Thus it is essential to analyze, evaluate and introduce appropriate mitigation techniques for harmonic reduction in the power sy...

This paper represents the simulation of Shunt Active Power Filter(SAPF) based on p-q theory and using hysteresis current control to obtain the gating signals for three phase ac-dc converter. The proposed active power filter is employed to reduce the current Total Harmonic Distortion (THD) drawn by the non-linear load and compensate the reactive power. The PI controller is employed to reduce the...