In the KEKB storage rings, we have measured the current dependence of the betatron tunes and the damping rate to evaluate the broad-band transverse impedance. The measured impedances were cross-checked and exceeded the design value by a factor of more than five. The tranverse mode-coupling instability was observed in LER when chromaticity was reduced. We found that the main impedance source for...

More than ten of in-vacuum type insertion devices are installed in the SPring-8 storage ring. When their gap was closed, we observed the low frequency vertical coupled bunch instability. We consider that this instability is driven by resistive-wall impedance caused by the magnet blocks made of NdFeB, of which conductivity is two order lower than Aluminum. We calculated the resistivewall impedan...

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...

This paper presents a proposed adaptive impedance control that derived based on Center of Mass (CoM) of the hexapod robot for walking on the bottom of water or seabed. The study has been carried out by modeling the buoyancy force following the restoration force to achieve the drowning level according to the Archimedes’ principle. The restoration force need to be positive in order to ensure robo...

The measurement of the mutual impedance of thin circular loop antennas on an N-layered conducting medium at high frequency is calculated. The horizontal, vertical coplanar, perpendicular and vertical coaxial loop antennas have been presented, the comparison between them and the numerical results have been calculated. The displacement currents in free space and in the conducting medium are taken...

We describe the calculated resistive wall impedance of the vacuum chamber and the corresponding growth rate of coupled-bunch instabilities for the VSX light source, a Japanese third generation VUV and soft X-ray source with a beam energy of 2 GeV. The impedance calculation was performed for the normal Al vacuum duct and the SiC duct, a higher-order mode (HOM) absorber of the damped RF cavity. T...

The finite-difference time-domain (FDTD) technique has been used to model the one-dimensional (1-D) surface impedance of a lossy earth plane having discontinuities in two and three dimensions. Using a horizontal magnetic field aperture source located five cells from an absorbing boundary and 35 cells above the lossy earth plane, the surface impedance was accurately modeled at a distance of 0=50...

The RHIC luminosity upgrade program aims for an increase of the polarized proton luminosity by a factor 2. To achieve this goal a significant increase in the beam intensity is foreseen. The beam coupling impedance represents a source of detrimental effects for beam quality and stability at high bunch intensities. In this paper, we evaluate the global transverse impedance in both the AGS and RHI...

This paper presents a microfluidic device with electroplated vertical electrodes in the side walls for impedance measurement. Based on the proposed device, the impedance of NaCl solutions with different concentrations and polystyrene microspheres with different sizes was measured and analyzed. The electroplating and SU-8-PDMS (SU-8-poly(dimethylsiloxane)) bonding technologies were firstly integ...