Frequency and time-domain measurements on humid sand and soil

Anis, M. K.; Jonscher, A. K.

doi:10.1007/bf01159846

Cited by 17 publications

(9 citation statements)

References 9 publications

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“…which emphasizes molecular polarization and charge storage For clays with high attenuation, reasonable data was achieved (Anis and Jonscher, 1993). The *( f ) and ε*( f ) are internearly to 1 GHz (Logsdon andLaird, 2004a, 2004b); however, related:…”

Section: Methodsmentioning

confidence: 76%

Soil Dielectric Spectra from Vector Network Analyzer Data

Logsdon¹

2005

Soil Science Soc of Amer J

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For more than two decades, dielectric properties (i.e., permittivity) the midpoint of the change in the real component. Water have been used for soil water content measurements, but unexpected results have been shown for saline soils or soils high in smectite clays. has a sharp dielectric relaxation, which means there is Permittivity is complex with real and imaginary components, and varies a large increase, and then a leveling off of the real permitwith frequency. The frequency dependence is due to dipole rotation tivity at frequencies below the relaxation frequency. In the and charge migration processes under alternating current. Dielectric range of most dielectric measurements in soil (10 MHz to relaxation refers to the reorienting of molecules after an electrical field 1.5 GHz), there is very little change in the real component is removed. The objective of this study was to develop a procedure for of permittivity free water. Also, the permittivity of dry determining complex permittivity spectra for soils. Six soils with a soil and air do not change with frequency. However, when range of mineralogies were preequilibrated at four duplicated water all are mixed together, there is often a large increase in contents. They were packed into truncated coaxial cells, and the reflecreal permittivity as the frequency decreases. The spectra tion-scattering parameter was measured for frequencies between 300 become complicated because of overlapping relaxations kHz to 3 GHz, although the primary calculation procedure was valid to Ͻ100 MHz. The calculated complex permittivity was difficult to use and overlapping electrical conductivity contribution to for deriving unique parameters because of overlapping influence of the imaginary component of permittivity. The relaxations electrical conductivity and multiple dielectric relaxation processes are due to interactions between the soil particles and that extended beyond the measured frequency range. The complex water; that is, not all of the water behaves like free water. resistivity was easier to interpret, clearly showing one major relaxation Material scientists have usually measured permittivity process, except for the driest soils. The relaxation frequency determined on very small samples that can be filled, cut, or packed from complex resistivity increased significantly as water content and into airlines (7-mm diam.), but this is much too small electrical conductivity increased. For each soil, the square root of for soil analysis. Material scientists have depended on apparent permittivity, ε a 1/2 , significantly increased as frequency detime domain measurements (converted to frequency docreased and as water content increased. The ε a 1/2 showed frequency main by lumped capacitance approach; Cole et al., 1989; dependence ranging from 1.1-fold per order of magnitude for Cecil soil to almost 2.5-fold for Ida soil. Developing procedures to extend Berberian and King, 2002) because of the broad meathe measured and calculated frequency range would enhance data surement frequency ...

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Section: Methodsmentioning

confidence: 76%

Soil Dielectric Spectra from Vector Network Analyzer Data

Logsdon¹

2005

Soil Science Soc of Amer J

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“…DS has been proven to provide information about the relationship between microstructure, electrical properties, and chemical processes in porous materials. [25][26][27][28][29] The technique can also be used, e.g., for analysis of the fractal surface structure 30 and ion intercalation process 31-35 of porous electrochromic materials, for counting the number of viable bacteria in moist environments 36 as well as for assessing structural 37 and mucoadhesive 38 properties of pharmaceutical gel systems.…”

Section: Introductionmentioning

confidence: 99%

Water and ion transport in ultra-adsorbing porous magnesium carbonate studied by dielectric spectroscopy

Pochard

Frykstrand

Ahlström

et al. 2014

Journal of Applied Physics

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Porous materials are used in application areas ranging from drug and vaccine delivery, medical implants, molecular sieves and cosmetics to catalysis and humidity control. In the present work, we employed an alternative approach to gain in-depth understanding about water interaction properties in such materials by the use of dielectric spectroscopy and thereby show that it is possible to obtain information that is not accessible from the more commonly employed water interaction analysis techniques. Specifically, the complex dielectric response of Upsalite, a novel, super-hydroscopic, high-surface area, porous magnesium carbonate material was measured in isothermal frequency scans between 10−3 and 106 Hz at controlled relative humidity (RH). We found the dielectric constant of the dry material to be 1.82. The ratio of bound to free water present in Upsalite after adsorption at room temperature was found to be high irrespective of the surrounding humidity with values ranging from ∼67% to ∼90%. We further found that OH− ions are the charge carriers responsible for the electrode polarization observed in the dielectric response and that the amount of these ions that are free to move in the material corresponds to a concentration of the order of 1–10 μmol l−1 independent of RH. Finally, the OH− diffusion coefficient displayed a drastic decrease with decreasing RH, typical of transport in unsaturated conditions. The presented results provide detailed insight about water interactions in the novel water adsorbing material under study and it is foreseen that the employed analysis methods can be used to evaluate other types of moisture adsorbing materials as well as the movement of functional species in the pores of inorganic drug delivery materials and materials tailored for adsorption of harmful charged species.

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“…Electrical resistivity (inverse of conductivity) of a soil is a function of soil mineralogy; particle size, shape and orientation; temperature; water content; time; and type and viscosity of the pore fluid if present (ANIS and JONSCHER, 1993;OKOYE et al, 1995). ARCHIE (1942) used electrical resistivity logs to determine some reservoir characteristics.…”

Section: Introductionmentioning

confidence: 99%

“…The electrical behavior of geomaterials is very complex and it can vary with time (ANIS and JONSCHER, 1993). At present, there are many models describing the electrical conduction behavior of soil and rock.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Electrical Conduction in Geomaterials by SPICE

Yeung

Akhtar

2008

Pure appl. geophys.

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Electrical responses of the subsurface can be used to identify geologic strata, locate anomalies, detect and delineate contamination, among many other applications. All these applications depend on the spatial variations of electrical properties in the subsurface and the resulting flow pattern of electric current. Due to the heterogeneity of the subsurface and complex boundary conditions, three-dimensional electric current flow problems are not easy to analyze, in particular when the response is frequency-and/or time-dependent. In this paper, a method of electric circuit analogy is proposed to simulate the electrical responses of geomaterials using the circuit simulator SPICE. The technique will allow simulation of more complex electrical conduction behavior of geomaterials without much extra effort. The excellent agreement between simulated results and analytical solutions developed for surface geophysical techniques establishes the viability of the method. Limitations of the approach and potential solutions to relax these limitations, and other potential applications of the technique in geosciences are also discussed.

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Frequency and time-domain measurements on humid sand and soil

Cited by 17 publications

References 9 publications

Soil Dielectric Spectra from Vector Network Analyzer Data

Soil Dielectric Spectra from Vector Network Analyzer Data

Water and ion transport in ultra-adsorbing porous magnesium carbonate studied by dielectric spectroscopy

Simulation of Electrical Conduction in Geomaterials by SPICE

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