Evaluation of diffusion-driven material property profiles using three-wavelength interdigital sensor

Abstract

The response of a three-wavelength interdigital dielectrometry sensor to the moisture diffusion process in oil-impregnated transformer pressboard has been simulated using an empirical relationship between the moisture concentration and the dielectric properties of the pressboard. A benchmark test of the moisture diffusion process has been developed with the purpose of comparing alternative parameter estimation algorithms used in w-lc (frequency wavenumber) dielectrometry. The results of simulations highlight characteristic features of the multi-wavelength sensor respon e delay from the start of the transient moisture diffusion process ngth, the influence of moisture boundary conditions, and the r nitude and variations of dielectric properties. One of the parameter estimation algorithms, linear calibrated admittancebased estimation (LCABE), has been applied to both simulated and measured data. Adequate performance of the LCABE approach in the absence of strong ,discontinuities of dielectric properties in the electric field penetration region is demonstrated and contrasted to an electrically shielded region case, in which the signal response becomes nonlinear. The proposed approach offers significant potential for the measurement of diffusion processes in various dielectrics, especially for cases with highly irregular geometry or material structure. Measurement results from moisture diffusion process monitoring are included. Parameter estimation of measurement results with LCABE confirm its applicability to the monitoring of moisture dynamics in transformer pressboard.

Design considerations in the use of interdigitated microsensor electrode arrays (IMEs) for impedimetric characterization of biomimetic hydrogels

“…Similarly, the solution resistance displays a value that is dependent upon the size of the electrode. The solution resistance becomes larger with decreasing size of the electrode as it is governed by the penetration depth (l/3) of the electrical field into the electrolyte (Manishev et al 2001). Since the measured resistance should be influenced by the volume of solution sampled in the space proximal to the IME surface, an increase in resistance with decreasing volume (smaller device) is expected.…”

Broad-Range Hydrogel-Based pH Sensor with Capacitive Readout Manufactured on a Flexible Substrate

“…These other substances may also enter the hydrogel if the particles are small enough to enter the network of the hydrogel, though it might be possible to build a filter ontop of the hydrogel to minimize this risk. The E PD is defined as (W + G)/3 [34] and can be adjusted by changing the width, W, and gap, G, of the electrodes. Figure 4 shows the results from a simulation considering three cases; single layer, double layer or alternating, as described in the Theory section.…”

“…The distance E PD can be calculated as one third of the width of the electrode plus the gap between electrodes, E PD ≈ (W + G)/3 [34]. Relation between capacitance and the distance to a material under test, which is placed a distance z from an interdigital capacitance.…”

Parallel double-plate capacitive proximity sensor modelling based on effective theory

“…However, the equation for the fringing capacitance is very complicated and it has an infinite summation involving the modified Bessel functions which themselves have infinite summations. A. V. Mamishev et al [4][5][6] did a series of research on interdigital sensor structure, including sensor multi-wavelength optimization, sensor modeling and sensor structure improvement, and all of these work are based on experimental results and simulation results. Meanwhile, the capacitive proximity sensor technique has been applied to some areas, such as civil engineering, agriculture and manufacture industries.…”