this paper is concerned with investigation of vertical impedance function of a surface rigid circular foundation resting on a semi-infinite transversely isotropic alluvium. to this end, the equations of motion in cylindrical coordinate system, which because of axissymmetry are two coupled equations, are converted into one partial differential equation using a method of potential function. the g...

background: sound is one of the most important factors threatening workers’ health. the most efficient and practical method for controlling noise pollution is the use of sound-absorbing materials. impedance tube with two microphones is used to determine the sound absorption coefficients and should be tested periodically for accuracy and efficiency. the purpose of present study was assessing the...

This paper presents a novel impedance-based approach for out-of-step (OOS) protection of a synchronous generator. The most popular and commonly used approaches for detecting OOS conditions are based on the measurement of positive sequence impedance at relay location. However, FACTS devices change the measured impedance value and thus disrupt the performance of impedance-based relay function. In...

This paper is concerned with investigation of vertical impedance function of a surface rigid circular foundation resting on a semi-infinite transversely isotropic alluvium. To this end, the equations of motion in cylindrical coordinate system, which because of axissymmetry are two coupled equations, are converted into one partial differential equation using a method of potential function. The g...

In this paper, a novel approach based on the Thévenin tracing is presented to modified conventional impedance-based out-of-step (OOS) protection. In conventional approach, the OOS detection is done by measuring positive sequence impedance. However, the measured impedance may be change due to different factors such as capacitor bank switching and reactive power compensators that it can cause the...

The corrosion inhibition effect of N,N′-bis(n-Hydroxybenzaldehyde)-1,3-Propandiimine on mild steel has been investigated in 1 M HCl using electrochemical impedance spectroscopy. A predictive model was presented for Nyquist plots using an artificial neural network. The proposed model predicted the imaginary impedance based on the real part of the impedance as a function of time. The model to...

this paper presets a method including a combination of the wavelet transform and fuzzy function approximation (ffa) for high impedance fault (hif) detection in distribution electricity network. discrete wavelet transform (dwt) has been used in this paper as a tool for signal analysis. with studying different types of mother signals, detail types and feeder signal, the best case is selected. the...