The influence of salinity on acoustic and electrical properties of frozen soils

2019 ◽  
pp. 99-106
Author(s):  
A. V. Koshurnikov ◽  
P. I. Kotov ◽  
I. A. Agapkin
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Water Content ◽  
Soil Salinity ◽  
Pore Solution ◽  
Saline Soils ◽  
Frozen Soils ◽  
Longitudinal Waves ◽  
Wave Velocities ◽  
Specific Electrical Resistivity

The results of determining acoustic and electrical properties of frozen saline soils (sand and silt) of massive cryogenic texture at different water content (3 values for each type of soil), salinity (7 values for silt and 5 for sand) and temperatures (–2, –4, –6 ᵒC) are given in the article. As a result, data on the high correlation between specific electrical resistivity and concentration of the pore solution and between ratio of a concentration of the pore solution to temperature and the velocity of longitudinal waves were obtained. Electrical resistivity can decrease by 2–22 times during the transition from a low-saline to a highly saline state and for longitudinal wave velocities only two times. Therefore, it is the electrical properties that are most suitable for the ranking of soils by the degree of salinity.

Acoustic velocities and electrical properties of frozen sandstones and shales

1977 ◽  
Vol 14 (5) ◽  
pp. 1004-1013 ◽  
Author(s):  
M. S. King
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Phase Angle ◽  
The Arctic ◽  
Frequency Range ◽  
Ultrasonic Velocities ◽  
Sharp Reduction ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Acoustic Velocities

Ultrasonic velocities and electrical properties have been measured in the laboratory at permafrost temperatures on a number of samples of sandstones and a shale which had been recovered from boreholes in the arctic and stored in their natural frozen state. Compressional and shear-wave velocities, electrical resistivity, and phase-angle relationships in the frequency range 0.005–100 kHz have been measured on the permafrost samples, at temperatures in the range −18 °C–+4 °C.Results of the tests show that, at a particular temperature, there is a small decrease in the electrical resistivity measured on all samples tested as the frequency is increased. The phase-angle differences measured show no consistent relationship with either frequency or temperature, but they are all less than 12° in magnitude. The electrical resistivity at a particular frequency and the ultrasonic velocities are affected in a similar manner by changes in temperature. Whereas the sandstones show a sharp reduction in velocities and resistivity as the temperature is raised to 0 °C or above, the shale shows little dependence of these parameters on changes in temperature in the range tested. An increase in shale content of the sandstone results in behavior intermediate between that of a clean sandstone and that of a shale.

Electrical Resistivity and Dielectric Properties of Hardened Cement Paste and Mortar

1995 ◽  
Vol 411 ◽  
Author(s):  
D. Buerchler ◽  
B. Elsener ◽  
H. Boehni
Keyword(s):  
Electrical Resistivity ◽  
Dielectric Properties ◽  
Water Content ◽  
Cement Paste ◽  
Pore Solution ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Solution Composition ◽  
Cement Based Materials

ABSTRACTWater content, porosity, pore solution composition, resistivity and dielectric properties of hardened cement paste and mortar samples have been studied as a function of time and relative humidities. A model for the resistivity of cement based materials is presented and an interpretation of the dielectric properties is proposed.

A simple numerical model to estimate water availability in saline soils

Soil Research ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 264 ◽  
Author(s):  
Mohammad Hossein Mohammadi ◽  
Mahnaz Khataar
Keyword(s):  
Numerical Model ◽  
Water Content ◽  
Soil Water ◽  
Water Uptake ◽  
Soil Salinity ◽  
Irrigation Water ◽  
Weighting Function ◽  
Water Salinity ◽  
Irrigation Water Salinity ◽  
Evapotranspiration Rate

We developed a numerical model to predict soil salinity from knowledge of evapotranspiration rate, crop salt tolerance, irrigation water salinity, and soil hydraulic properties. Using the model, we introduced a new weighting function to express the limitation imposed by salinity on plant available water estimated by the integral water capacity concept. Lower and critical limits of soil water uptake by plants were also defined. We further analysed the sensitivity of model results to underlying parameters using characteristics given for corn, cowpea, and barley in the literature and two clay and sandy loam soils obtained from databases. Results showed that, between two irrigation events, soil salinity increased nonlinearly with decreasing soil water content especially when evapotranspiration and soil drainage rate were high. The salinity weighting function depended greatly on the plant sensitivity to salinity and irrigation water salinity. This research confirmed that both critical and lower limits (in terms of water content) of soil water uptake by plants increased with evapotranspiration rate and irrigation water salinity. Since the presented approach is based on a physical concept and well-known plant parameters, soil hydraulic characteristics, irrigation water salinity, and meteorological conditions, it may be useful in spatio-temporal modelling of soil water quality and quantity and prediction of crop yield.

Production and properties of Cu-ZrO2 nanocomposites

2017 ◽  
Vol 52 (11) ◽  
pp. 1519-1529 ◽  
Author(s):  
Adel Fathy ◽  
Omayma Elkady ◽  
Ahmed Abu-Oqail
Keyword(s):  
Electron Microscopy ◽  
Electrical Resistivity ◽  
Thermal Expansion ◽  
Wear Rate ◽  
Coefficient Of Thermal Expansion ◽  
Diffraction Field ◽  
Dry Sliding Wear ◽  
Surface Composite ◽  
Developed Surface ◽  
Specific Electrical Resistivity

In the present study, Cu–3, 6, and 9 wt.% of ZrO2 nanocomposites were prepared by an in situ reactive synthesis of copper nitrate Cu(NO3)2 and zirconium oxychloride ZrOCl2. The structure and characteristics were examined by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. The results showed that the nanosized ZrO2 particles with about 45 nm was successfully formed and dispersed within the copper matrix. The effect of ZrO2 nanoparticles content on relative density, Vickers hardness, specific electrical resistivity, and coefficient of thermal expansion was evaluated. The pin-on-disc test was also performed to determine dry sliding wear behavior of specimens under different wear conditions. Hardness and specific electrical resistivity increased and density of Cu-ZrO2 nanocomposites decreased with increasing amount of ZrO2 in Cu matrix. The coefficient of thermal expansion significantly increased with increasing temperature but decreased with increasing ZrO2. The wear rate and friction coefficient of the developed surface composite was found decreasing with respect to increase in the dispersion of ZrO2. Amongst the copper surface composite, specimen with 9 wt.% of ZrO2 has shown the least wear rate with low coefficient of friction.

scholarly journals Analysis of the Dielectric Constant of Saline-Alkali Soils and the Effect on Radar Backscattering Coefficient: A Case Study of Soda Alkaline Saline Soils in Western Jilin Province Using RADARSAT-2 Data

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Yang-yang Li ◽  
Kai Zhao ◽  
Jian-hua Ren ◽  
Yan-ling Ding ◽  
Li-li Wu
Keyword(s):  
Dielectric Constant ◽  
Soil Salinity ◽  
Frequency Effect ◽  
Complex Dielectric Constant ◽  
Saline Soils ◽  
Suitable Model ◽  
Backscattering Coefficient ◽  
Mixed Pixel ◽  
Western Jilin Province

Soil salinity is a global problem, especially in developing countries, which affects the environment and productivity of agriculture areas. Salt has a significant effect on the complex dielectric constant of wet soil. However, there is no suitable model to describe the variation in the backscattering coefficient due to changes in soil salinity content. The purpose of this paper is to use backscattering models to understand behaviors of the backscattering coefficient in saline soils based on the analysis of its dielectric constant. The effects of moisture and salinity on the dielectric constant by combined Dobson mixing model and seawater dielectric constant model are analyzed, and the backscattering coefficient is then simulated using the AIEM. Simultaneously, laboratory measurements were performed on ground samples. The frequency effect of the laboratory results was not the same as the simulated results. The frequency dependence of the ionic conductivity of an electrolyte solution is influenced by the ion’s components. Finally, the simulated backscattering coefficients measured from the dielectric constant with the AIEM were analyzed using the extracted backscattering coefficient from the RADARSAT-2 image. The results show that RADARSAT-2 is potentially able to measure soil salinity; however, the mixed pixel problem needs to be more thoroughly considered.

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