A simplified experimental method to study conductivity percolation.

A simplified experimental setup and a measurement method adapted to the simplified data analysis proposed in previous works are described in detail. The setup is intended for investigation of the conductivity percolation in the water network formed on granular materials and studied in the course of dehydration. The results show that the new, easily accessible experimental setup enables determination of the principal percolation parameters with the same accuracy as the more sophisticated equipment employing an impedance analyzer.

Note: optimization of the numerical data analysis for conductivity percolation studies of drying moist porous systems.

A simplified data analysis protocol, for dielectric spectroscopy use to study conductivity percolation in dehydrating granular media is discussed. To enhance visibility of the protonic conductivity contribution to the dielectric loss spectrum, detrimental effects of either low-frequency dielectric relaxation or electrode polarization are removed. Use of the directly measurable monofrequency dielectric loss factor rather than estimated DC conductivity to parameterize the percolation transition substantially reduces the analysis work and time.

ESR lineshape and 1H spin-lattice relaxation dispersion in propylene glycol solutions of nitroxide radicals--joint analysis.

Electron Spin Resonance (ESR) spectroscopy and Nuclear Magnetic Relaxation Dispersion (NMRD) experiments are reported for propylene glycol solutions of the nitroxide radical: 4-oxo-TEMPO-d16 containing (15)N and (14)N isotopes. The NMRD experiments refer to (1)H spin-lattice relaxation measurements in a broad frequency range (10 kHz-20 MHz). A joint analysis of the ESR and NMRD data is performed.

Electric conductivity percolation in naturally dehydrating, lightly wetted, hydrophilic fumed silica powder.

In studying the dehydration of surface-moistened fumed silica Aerosil powders, we found a conductivity percolation transition at low hydration levels. Both the percolation exponent and the threshold are typical for correlated site-bond transitions in complex two-dimensional (2D) systems. The exponent values, 0.

1H relaxation dispersion in solutions of nitroxide radicals: influence of electron spin relaxation.

The work presents a theory of nuclear ((1)H) spin-lattice relaxation dispersion for solutions of (15)N and (14)N radicals, including electron spin relaxation effects. The theory is a generalization of the approach presented by Kruk et al. [J.