scholarly journals Interval uncertainty analysis of a confined aquifer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chengcheng Xu ◽  
Chuiyu Lu ◽  
Jianhua Wang
Keyword(s):  
Uncertainty Analysis ◽  
Variable Parameter ◽  
Lower Boundary ◽  
Mining Area ◽  
Rate Of Change ◽  
Interval Uncertainty ◽  
Water Inflow ◽  
Confined Water ◽  
Maximum Value ◽  
Allowable Rate

AbstractWater inflow forecast is influenced by many factors and yields uncertain results. To more accurately predict the magnitude of water inflow and quantitatively define the corresponding response in the parameter change interval, this study combined a non-probabilistic set theory and uncertainty analysis to derive an equation for the confined water inflow. Using mining area data and comparing the calculation of upper and lower boundary limits obtained by a Monte Carlo method, results of the confined water inflow equation were calculated with relative errors of 5% and 10%. When corresponding to the rate of change of the variable parameter, the results showed that under the same error conditions, the allowable rate of change when calculating the minimum value using Eq. A was greater than when using Eq. B, and the maximum value using Eq. B yielded a greater allowable rate of change than the maximum value calculated by Eq. A. Thus, the obtained rate of change for Eq. A is indicative of the lower limit, and Eq. B is conducive to the calculation of the upper limit of mine water inflow.

Water inflow characteristics of coal seam mining aquifer in Yushen mining area, China

2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Zhao Chunhu ◽  
Jin Dewu ◽  
Wang Qiangmin ◽  
Wang Hao ◽  
Li Zhixue ◽  
...  
Keyword(s):  
Coal Seam ◽  
Mining Area ◽  
Water Inflow ◽  
Seam Mining

Advanced Robust Optimization Approach for Design Optimization With Interval Uncertainty Using Sequential Quadratic Programming

2013 ◽  
Author(s):  
Jianhua Zhou ◽  
Mian Li
Keyword(s):  
Robust Optimization ◽  
Linear Equations ◽  
Variable Parameter ◽  
Optimal Solution ◽  
Interval Uncertainty ◽  
Computational Time ◽  
Optimization Approach ◽  
Engineering Optimization ◽  
Loop Optimization ◽  
New Approach

Uncertainty is inevitable in real world. It has to be taken into consideration, especially in engineering optimization; otherwise the obtained optimal solution may become infeasible. Robust optimization (RO) approaches have been proposed to deal with this issue. Most existing RO algorithms use double-looped structures in which a large amount of computational efforts have been spent in the inner loop optimization to determine the robustness of candidate solutions. In this paper, an advanced approach is presented where no optimization run is required to be performed for robustness evaluations in the inner loop. Instead, a concept of Utopian point is proposed and the corresponding maximum variable/parameter variation will be obtained by just solving a set of linear equations. The obtained robust optimal solution from the new approach may be conservative, but the deviation from the true robust optimal solution is very small given the significant improvement in the computational efficiency. Six numerical and engineering examples are tested to show the applicability and efficiency of the proposed approach, whose solutions and computational time are compared with those from a similar but double-looped approach, SQP-RO, proposed previously.

Chemical Analyses of Middle and Upper Pennsylvanian Coals from Southeastern Kansas

1997 ◽  
pp. 43-65
Author(s):  
Lawrence L. Brady ◽  
Joseph R. Hatch
Keyword(s):  
Bituminous Coal ◽  
Geometric Mean ◽  
Zinc Content ◽  
Mining Area ◽  
Volatile Matter ◽  
Arithmetic Mean ◽  
Cadmium Content ◽  
Chemical Analyses ◽  
Mean Values ◽  
Maximum Value

Elemental and chemical analyses and physical tests were conducted on 36 samples of Middle and Upper Pennsylvanian coals from southeastern Kansas. Concentrations of 35 minor and trace elements in these coals were statistically compared with concentrations in coals of similar rank and age from other areas in the western region of the Interior Coal Province, showing that Kansas coals have significantly higher concentrations of copper, arsenic, and lead. The zinc content in Kansas coal samples ranges from 160 to 51,000 ppm (whole-coal basis), the maximum value being the highest zinc value reported for U.S. coals. Cadmium content also has an extreme range, from less than 1.0 to 160 ppm (whole-coal basis), the maximum value being one of the highest cadmium values reported in U.S. coals. The apparent ranks of these coal samples range from high-volatile B to high-volatile A bituminous coal. Most samples of Middle Pennsylvanian coals from the major coal-mining area in Bourbon, Crawford, and Cherokee counties are high-volatile A bituminous coal. Arithmetic mean values for proximate analyses of coals (as-received basis; n = 25) show these coals to be 15.5% ash, 35.3% volatile matter, 45.9% fixed carbon, and 3.3% moisture and to have a heat of combustion of 11,910 Btu/lb. Arithmetic mean values for ultimate analyses of the coals show these coals to be 4.9% hydrogen, 65.3% carbon, 1.2% nitrogen, 5.5% sulfur, and 7.7% oxygen. The geometric mean values of these Kansas coals are 3.03% pyritic sulfur, 1.25% organic sulfur, and 0.2% sulfate sulfur.

Sign in / Sign up

Export Citation Format

Share Document