scholarly journals The Self-Potential Anomaly Produced by a Subsurface Flow at the Contact of Two Horizontal Layers and Its Quantitative Interpretation

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Georgios Aim. Skianis
Keyword(s):  
Amplitude Spectrum ◽  
Underground Water ◽  
The Self ◽  
Stratified Medium ◽  
Geothermal System ◽  
Direct Interpretation ◽  
Image Technique ◽  
The Fourier Transform ◽  
Self Potential ◽  
Horizontal Layers

In the present paper the problem of a polarized cylinder with a small cross-section, which is located at the contact of two horizontal layers with different resistivities, is studied. Such a polarization geometry simulates the self-potential (SP) field produced by a horizontal flow at the contact between the two layers. First, the expression of the self potential at the space domain is derived, applying the image technique. Then, the expression for the Fourier transform of the SP anomaly is found and the behavior of the amplitude spectrum is studied. Based on this study, a direct interpretation method at the spatial frequency domain is proposed, in order to calculate the depth of the flow and the reflection coefficient of the stratified medium. Experimentation with a synthetic model shows that the method works well (small deviations between true and calculated values). When the SP curve contains noise, deviations between calculated and true depths are smaller than those between calculated and true reflection coefficients. The proposed method, which is also applied on SP data from a geothermal system (Mauri et al., 2010), may be useful in detecting underground water or heat flows.

scholarly journals Mapping the Pollution Plume Using the Self-Potential Geophysical Method: Case of Oum Azza Landfill, Rabat, Morocco

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 961
Author(s):  
Meryem Touzani ◽  
Ismail Mohsine ◽  
Jamila Ouardi ◽  
Ilias Kacimi ◽  
Moad Morarech ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Water Table ◽  
Soil Surface ◽  
The Self ◽  
Drainage Network ◽  
Geophysical Method ◽  
Direct Measurements ◽  
Sandy Material ◽  
The City ◽  
Self Potential

The main landfill in the city of Rabat (Morocco) is based on sandy material containing the shallow Mio-Pliocene aquifer. The presence of a pollution plume is likely, but its extent is not known. Measurements of spontaneous potential (SP) from the soil surface were cross-referenced with direct measurements of the water table and leachates (pH, redox potential, electrical conductivity) according to the available accesses, as well as with an analysis of the landscape and the water table flows. With a few precautions during data acquisition on this resistive terrain, the results made it possible to separate the electrokinetic (~30%) and electrochemical (~70%) components responsible for the range of potentials observed (70 mV). The plume is detected in the hydrogeological downstream of the discharge, but is captured by the natural drainage network and does not extend further under the hills.

Experimental study of the self-potential anomaly caused by coal fires

2017 ◽  
Vol 145 ◽  
pp. 124-132 ◽  
Author(s):  
Zhenlu Shao ◽  
Deming Wang ◽  
Yanming Wang ◽  
Xiaoxing Zhong ◽  
Yunxiang Zhang ◽  
...  
Keyword(s):  
Experimental Study ◽  
The Self ◽  
Coal Fires ◽  
Self Potential

Mapping Fracture Flow Anisotropy Using the Self Potential Method: Field and Laboratory Experiments

2021 ◽  
Author(s):  
Y. Kumar ◽  
J. Comte ◽  
J. Vinogradov ◽  
D. Healy ◽  
J. Mezquita Gonzalez ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Potential Method ◽  
The Self ◽  
Fracture Flow ◽  
Self Potential ◽  
Flow Anisotropy

scholarly journals Self-potential response characteristics of red sandstone samples under uniaxial compression

2019 ◽  
Vol 16 (4) ◽  
pp. 742-752
Author(s):  
Cai Yang ◽  
Shengdong Liu ◽  
Haiping Yang
Keyword(s):  
Rock Mass ◽  
Uniaxial Compression ◽  
Inflection Point ◽  
Radial Direction ◽  
The Self ◽  
Potential Difference ◽  
Potential Response ◽  
Red Sandstone ◽  
Response Characteristics ◽  
Self Potential

Abstract Deformation and rupture of rock mass under loading cause the variation of electric potential. Response characteristics of self-potential and stress during the complete stress-strain process of red sandstones play an important role in evaluating the stress state of sandstone on the basis of self-potential. Experimental results demonstrate that the stress of red sandstone under uniaxial compression is linearly correlated with the self-potential difference before the first inflection point in the initial stage of loading. The average variation rate of self-potential difference and stress is 0.1325 mV MPa−1. As the loading pressure gradually increases and enters the softening stage (before the maximum loading point), the catastrophic points of uniaxial loading stress correspond to the inflection point of self-potential. The self-potential of red sandstone varies in a range of 0–45.6 mV in that case and it fluctuates most significantly around the maximum loading point, with a range of 0.3–195.5 mV. In the end stage of loading, the macroscopic rupture of the red sandstone sample is complete, the self-potential of red sandstone fluctuates slightly around the maximum load point and then gradually stabilizes. Moreover, it is found that self-potentials change more significantly in the radial direction than in the axial direction in the uniaxial compression experiment, indicating that self-potentials generated by rock mass rupture are more sensitive in the radial direction. The rupture process of red sandstone can be dynamically represented by the tempo-spatial evolution profiles of self-potential.

scholarly journals A Study on Improving the Coefficient of Performance by Comparing Balancing Well and Standing Column Well Heat Exchange Systems

2020 ◽  
Vol 12 (24) ◽  
pp. 10445
Author(s):  
Myungkwan Lim ◽  
Kyoungbin Lim ◽  
Changhee Lee
Keyword(s):  
Thermal Conductivity ◽  
Heat Exchanger ◽  
Effective Thermal Conductivity ◽  
Water Discharge ◽  
Underground Water ◽  
Coefficient Of Performance ◽  
Geothermal System ◽  
Heat Accumulation ◽  
Heating And Cooling ◽  
Discharge Water

This study proposed a technology to improve the performance characteristics and coefficient of performance (COP) of a geothermal system by fundamentally preventing underground water discharge and maintaining a constant temperature of the underground heat exchanger composed of bleed discharge water that utilizes two balancing wells using cross-mixing methods. Using the standing column well (SCW) and cross-mixing balancing well underground heat exchanger, we compared and analyzed the effective thermal conductivity characteristics and COP characteristics during heating and cooling modes. Consequently, the cross-mixing balancing well underground heat exchanger exhibited more effective thermal conductivity than the SCW underground heat exchanger, with a high COP. Therefore, suggesting the performance was improved using groundwater flow rather than SCW. The comparison and analysis results of the effective heat map characteristics using the results of the SCW and balancing well system showed that the heating operation for the SCW underground heat exchanger had better thermal conductivity characteristics than the cooling operation. In addition, regarding a balancing well underground heat exchanger, the cooling operation exhibited superior thermal conductivity characteristics. Thus, the performance was considered to have improved due to the flow of activated groundwater in the ground and the rapid heat transfer without heat accumulation.

scholarly journals Measurement and analysis of truck vibrations during off-road transportation

2018 ◽  
Vol 211 ◽  
pp. 13003
Author(s):  
Dariusz Grzesica
Keyword(s):  
Amplitude Spectrum ◽  
Road Transportation ◽  
The Road ◽  
Rate Acceleration ◽  
Measurement And Analysis ◽  
Vehicle Security ◽  
On The Road ◽  
Vertical Vibrations ◽  
The Fourier Transform ◽  
The Impact

Measurement of vibration of the vehicle on the road surface is one of the key elements of cargo and vehicle security. This paper provides results from transporting military cargo study that analyzed the various vibrations of acceleration during transport on a stony pavement road. The data include vibrations from three directions: longitudinal, transverse and vertical. Based on collected data the quantitative analysis of vibrations was conducted. The peak acceleration as well as the acceleration level was identified. The growth rate acceleration affecting the smoothness of driving and the impact of the vehicle on the stony surface were calculated. The study shows that the greatest impact on transporting cargo have vertical vibrations. In addition, using the Fourier transform, amplitude spectrum for all directions of oscillation was assigned.

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