Sound propagation i gas-filled capillary-tube-type orous media was investigated. The capillary tubes were taken to be nominally straight with very small pores in the walls of the capillary tubes. The complex wave number and the characteristic mpedance of such media were evaluated. Application to ceramic samples having capillary pores with square cross sections and porous walls is developed as a...

In this work, polypyrrole/ZnO nanocomposite (PPy/ZnO NC) was produced through synthesis of polypyrrole polymer in the presence of ZnO nanoparticles. The corrosion behavior of polyvinyl butyral coatings without and with different weight percentages of nanocomposite on the surface of 7075 Al alloy was investigated in 3.5% NaCl solution at different immersion times using electrochemical impedance ...

The paper presents an original fabrication process of a microfluidic device for identification and characterization of cells in suspensions using mpedance spectroscopy. The device consists of two glass wafers: a bottom wafer comprising a microfluidic channel with two electrodes added or impedance measurement, and a top glass wafer in which inlets and outlets are realized. The fact that the devi...

The fluctuations of the position of monatomic steps on Ag (111) are investigated by Scanning Tunneling Microscopy (STM). We analyze the influence of tip-sample interact~on by varying the gap ~mpedance over more than two orders of magnitude. For tunneling tips providing a weak tip-sample interact ion, we show that the step position au~ocorrelation function remains essentially unaltered. In this ...

Algebraic expressions are given (in FORT•aAN format for convenient use) that accurately approximate the value of the per unit-length acoustic impedance of small tubes (radii less than • acoustic wavelength) including isothermal nd viscous effects. Their accuracy of typically 3% or better was obtained as a result of adding a shunt conductance t rm to the traditional approximations and including ...

Electrical I mpedance Tomography ( EIT) i s a non -invasive i maging technique which consists on placing a number of electrodes (normally 8, 16 or 32) equidistantly a round the periphery of the object to be s tudied. One of the preferred methods for obtaining a projection for image reconstruction uses an alternating current signal injected between a pair of adjacent electrodes and the voltage d...

1 TRACT erimental results obtained during fatigue testing of a lded lap-shear structural-joint specimen are d. In these experiments, the electro-mechanical mpedance technique was used for structural health ing, damage detection, and NDE. The test ns were instrumented with piezo-electric wafer ers, and the base E/M impedance signature was over the relevant frequency range. Fatigue testing lied t...

The decision of digital distance relay is very important for making the protection scheme in the transmission system more reliable. As the current signal is taken from the output of the current transformer, the distortion introduced by the saturation in it affects the performance of the distance relay. In this context proper nonlinear modeling of current transformer is necessary and a suitable ...