The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Xiaosong Huang - One of the best experts on this subject based on the ideXlab platform.
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Using stress wave technology for leakage detection in a landfill Impervious Layer
Environmental Science and Pollution Research, 2019Co-Authors: Yayu Chen, Huanyi Sun, Wei Zhang, Xiaosong HuangAbstract:This paper proposes a stress wave monitoring method for monitoring and locating leakage through the Impervious Layer at a landfill to resolve the “first pollution, then discovery” problem caused by the existing electrical monitoring method. The experimental results show that the linear distance to the geophones from the leak point should be less than 31.5 m to provide a well-defined rupture signal. The amplitudes of the stress wave signals generated during the yield and rupture stages of the high-density polyethylene (HDPE) film are more obvious and easily identified by the geophones; the rupture signal duration is approximately 100 ms, and the bandwidth is distributed within 0 kHz to 1 kHz. By studying the stress wave first arrival times calculated by the picking model, the average error of the picking model is approximately 0.35 ms, and the iteration of the model is ceased when the thresholds of the discriminating indices are 3.5 and 0.9. Experiments reveal that the positioning model should stop iterating when the absolute value of each element in the calibration vector is less than 140. The average positioning error is 0.248 m, and the maximum fiducial errors of the positioning model in the X-axis and Y-axis directions are 0.32% and 0.58%, respectively.
K. V. G. K. Rao - One of the best experts on this subject based on the ideXlab platform.
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Effect of depth of Impervious Layer and adsorption on solute transport in tile-drained irrigated lands
Journal of Hydrology, 1994Co-Authors: S. K. Kamra, Sita Ram Singh, K. V. G. K. RaoAbstract:Abstract A two-dimensional finite element model of solute transport in a tile-drained soil-aquifer system was applied to study the effect of the depth of Impervious Layer and adsorption on salt distribution in the soil and groundwater, and the salinity of drainage effluent. The model considers steady state water flow in the unsaturated and saturated zones, and includes the effect of convective transport, dispersion and linear adsorption. The results indicate that though the depth of the Impervious Layer has little effect on salt distribution in the unsaturated zone, it significantly influences the quality of the drainage effluent. Further, it was found that during the initial years of reclamation of a highly saline soil with subsurface drainage, the effect of adsorption is more pronounced in the unsaturated zone than in the saturated zone and the movement of adsorbing solute species is retarded for a longer time in the groundwater than in the soil.
Yayu Chen - One of the best experts on this subject based on the ideXlab platform.
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Using stress wave technology for leakage detection in a landfill Impervious Layer
Environmental Science and Pollution Research, 2019Co-Authors: Yayu Chen, Huanyi Sun, Wei Zhang, Xiaosong HuangAbstract:This paper proposes a stress wave monitoring method for monitoring and locating leakage through the Impervious Layer at a landfill to resolve the “first pollution, then discovery” problem caused by the existing electrical monitoring method. The experimental results show that the linear distance to the geophones from the leak point should be less than 31.5 m to provide a well-defined rupture signal. The amplitudes of the stress wave signals generated during the yield and rupture stages of the high-density polyethylene (HDPE) film are more obvious and easily identified by the geophones; the rupture signal duration is approximately 100 ms, and the bandwidth is distributed within 0 kHz to 1 kHz. By studying the stress wave first arrival times calculated by the picking model, the average error of the picking model is approximately 0.35 ms, and the iteration of the model is ceased when the thresholds of the discriminating indices are 3.5 and 0.9. Experiments reveal that the positioning model should stop iterating when the absolute value of each element in the calibration vector is less than 140. The average positioning error is 0.248 m, and the maximum fiducial errors of the positioning model in the X-axis and Y-axis directions are 0.32% and 0.58%, respectively.
Ohtoshi Kunio - One of the best experts on this subject based on the ideXlab platform.
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Study on characteristics of coastal seawater encroachment with tidal river
2010Co-Authors: Ohtoshi KunioAbstract:The region area studied covers 3.2 km2 nearby the Pacific.First,it was proved that the aquifer in investigation area is composed of multiple Layer soil with different permeability and there are uneven Impervious Layer under the aquifer through surveying of 19 geologic wells.Second,the regularities of groundwater level and feature points of salt-fresh water mixing region changing with tidal fluctuation were investigated through water vertical conductivity of 10 wells which have different distance away from the coast,i.e.,the characteristics are different in different seasons at the same place.While the variation regularity would be different for different places in the same season because the geologic structure of the wells and the distances from seacoast and tidal river are different.It was greatly different to the common rules accepted by the human being to date.Moreover,the conclusion was obtained through surveying 36 electrical detecting points and vertical conductivity of well water that although the tidal river effects on the seawater encroachment,the seawater encroaches toward inland in wedge-shaped from the whole surveying region.A mathematical model was built according to the characteristics of Impervious Layer to give qualitative explanation for the results showed above.
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Discussion and research on laws of groundwater surface and fresh-salt water interface changing with tidal wave in coastal zone(II)
2008Co-Authors: Ohtoshi KunioAbstract:This paper studies the laws of natural groundwater surface and fresh-salt water interface of coastal aquifers on uneven Impervious Layer changing with tidal wave by using 2D numerical simulation mathematical model.That is,the phase difference between natural groundwater surface and fresh-salt water interface and vibration amplitude have relation to not only Impervious Layer shape but also hydraulic gradient of natural groundwater surface,permeability coefficient of aquifers and changing extent of Impervious Layer shape.
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Numerical simulation of fresh-saline water interface interactive regularities in coastal areas due to the tidal fluctuation
Applied Mechanics and Materials, 2007Co-Authors: Ohtoshi KunioAbstract:This paper is inclined to present a simple but effective 2D mathematical model to simulate the interactive regularities of fresh-saline water interface and natural groundwater surface in coastal aquifer.The above said model has been established on the basis of careful observation and investigation of the hydrologic and geologic characteristics of coastal aquifer and Impervious Layers and the features of seepage flow of fresh water and salt water in coastal aquifer.The model has also passed corresponding validity verification by comparing experimental data concerned.What is more important,the paper has carefully studied the interactive regularities of the interface change of the two kinds of water with the tidal fluctuation.That is to say,on the one hand,natural groundwater surface can be found similar to that of fresh-saline groundwater with the wave surge and the wave receding,with their fluctuation decrease with the increase of the distance from sea coast and increase with tiding surge.Moreover,the impact sphere of the tidal fluctuation on the natural groundwater surface can be much bigger than that on fresh-saline groundwater interface.On the other hand,the vibration impact of natural groundwater surface and fresh-saline groundwater interface on the oceans waters and the phase difference between them is closely related to the hydraulic gradient of natural groundwater surface,permeability coefficient and the active porosity of aquifer,shape and changing extent of Impervious Layer.But the phase difference is independent of tidal fluctuation amplitude in proportion to that of the tidal fluctuation.In addition,if the Impervious Layer shape is known,no matter what changes take place with the hydraulic gradient of natural groundwater surface and the other factors,no change will take place with phase difference between natural groundwater surface and fresh-saline groundwater interface and the position of peak value,i.e.,the changing trend of the phase difference is determined by Impervious Layer shape.Furthermore,if there are great differences between groundwater surface and fresh-saline groundwater interface in phase and vibration amplitude,it can be concluded that there would be uneven Impervious Layer under the aquifer.The greater this difference,the higher the convexo-concave degree of the Impervious Layer would be.
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Discussion and research on laws of groundwater surface and fresh-salt water interface change with tidal wave in coastal zone(I) Building of 2D numerical simulation mathematical model and verification of its validity
2007Co-Authors: Ohtoshi KunioAbstract:On the basis of studying geometric property and geological characteristics of widespread irregular Impervious Layer in the coastal zone,according to characteristics of groundwater seepage,a 2D numerical simulation mathematical model was built and different from the traditional models using the mathematical analysis.The model simulation of the changes of fresh-salt water interface of coastal aquifers was done.Moreover,its validity is verified by comparison with the experimental data.
Huanyi Sun - One of the best experts on this subject based on the ideXlab platform.
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Using stress wave technology for leakage detection in a landfill Impervious Layer
Environmental Science and Pollution Research, 2019Co-Authors: Yayu Chen, Huanyi Sun, Wei Zhang, Xiaosong HuangAbstract:This paper proposes a stress wave monitoring method for monitoring and locating leakage through the Impervious Layer at a landfill to resolve the “first pollution, then discovery” problem caused by the existing electrical monitoring method. The experimental results show that the linear distance to the geophones from the leak point should be less than 31.5 m to provide a well-defined rupture signal. The amplitudes of the stress wave signals generated during the yield and rupture stages of the high-density polyethylene (HDPE) film are more obvious and easily identified by the geophones; the rupture signal duration is approximately 100 ms, and the bandwidth is distributed within 0 kHz to 1 kHz. By studying the stress wave first arrival times calculated by the picking model, the average error of the picking model is approximately 0.35 ms, and the iteration of the model is ceased when the thresholds of the discriminating indices are 3.5 and 0.9. Experiments reveal that the positioning model should stop iterating when the absolute value of each element in the calibration vector is less than 140. The average positioning error is 0.248 m, and the maximum fiducial errors of the positioning model in the X-axis and Y-axis directions are 0.32% and 0.58%, respectively.
