Current Issue : October-December Volume : 2022 Issue Number : 4 Articles : 5 Articles
In order to scientifically guide the water-preserved mining of the coal seam floor and make up for the shortcomings in the conventional evaluation of water blocking performance of the coal seam floor, according to the system resilience theory, the difference between the vulnerability and resilience of the coal seam floor is analyzed, and three elements and nine indicators for evaluating water resistance toughness of the coal seam floor are determined. In the evaluation process, first of all, the maximum difference normalization method is used to conduct a dimensionless analysis of quantifiable indicators to determine the importance of the corresponding indicators, and the AHP software yaahp10.1 is used to determine the weight vector of each indicator. Secondly, the single-factor membership degree is determined according to the single-factor resilience grade classification criterion and membership function and finally combined with the weight vector for fuzzy synthesis calculation and comprehensive evaluation. The model is applied to a specific project. Research has shown that in the water hazard threat area of No. 10 coal seam floor in Jiegou Coal Mine, Anhui Province, the performance of system vulnerability elements is weak, the performance of system recoverability elements is better, and the performance of system adaptability elements is extremely poor. From the perspective of the whole life cycle, determining the treatment target area, optimizing the rock formation modification and repairing materials, and enhancing the water resources carrying capacity can improve the water resistance toughness of the coal seam floor. Related conclusions verify the effectiveness of the evaluation model. Furthermore, an optimized strategy for coal seam floor water retention mining is proposed: the technology system of water-preserved mining for coal seam floor contains 3 stages and 3 detections, which provides a scientific basis for the in situ protection of highpressure limestone water from coal seam floor....
Aiming at the problems of insufficient real time and accuracy of water quality online monitoring and large resource consumption, this paper proposes a water quality monitoring and early warning method based on edge computing. Combined with Internet of things technology and edge computing technology, an online water quality monitoring and early warning model is designed. Through the preprocessing of the collected source data, the monitoring accuracy is improved, and edge computing technology is introduced to preliminarily analyze and process the collected data in the monitoring station, so as to save network traffic and computing resources. On the basis of online monitoring, the water quality prediction model is established by using historical water quality monitoring data to realize water quality prediction and provide a basis for staff scientific decision-making. Engineering practice shows that the model has high application value....
The current study attempted to evaluate the water quality in terms of physico- chemical properties, metals, and bacteriological characteristics of the surface water available in Shigar Valley located along Shigar River in sub-district Shigar of district Skardu, Gilgit Baltistan (GB), Pakistan. A total of 17 water samples were collected during 2020 and analysed to perform multivariate analysis through principal component analysis (PCA) and cluster analysis (CA). Spatial distribution using inverse distance weight (IDW) interpolation was also utilised to determine the water quality in the valley to elucidate public health concerns. The study reveals that physico-chemical characteristics are the most important that affect water quality, followed by metals and bacteriological variables, according to a PCA application based on multivariate analysis. Examinations found that some of the metals including arsenic (As), copper (Cu), lead (Pb), iron (Fe), zinc (Zn), manganese (Mn), and molybdenum (Mo) and all bacteriological parameters enlisting total coliform count (TCC), total faecal coliform (TFC), and total faecal streptococci (TFS) are not following the WHO guidelines that could be hazardous from the public health viewpoint. The IDW-based spatial distribution indicates that water samples have an intermittent and unusual distribution of observed parameters. Having considerable community settlements, people in the valley have limited options and have no choice except to consume the available water as no alternate source is available. People hardly question the water quality and rarely examine the water potability. The study also demonstrated that combining PCA with IDW would be a powerful method for assessing water quality. It is suggested that the sources of contamination be investigated further in detail to reduce the pollution load of the surface water in the valley, which could aid in the development of sustainable ecotourism....
We investigated the different sources and their corresponding impact areas of Pu in Chinese surface soils to illustrate the state-of-the-art of the sources, levels and distributions of 240Pu/239Pu atom ratios as well as 239+240Pu activity concentrations in China. For the first time a moving average strategy in combination with statistical analysis was employed to partition geographic areas in China based on the reported 240Pu/239Pu atom ratio and 239+240Pu concentration data from public literature. During the partitioning, the median (MED) of the dataset was basically employed as a criteria in place of the commonly used arithmetic average (AM). Concisely, three areas were partitioned according to the different influences of Pu from the Lop Nor (LNTS) and Semipalatinsk (STS) test sites and the global fallout. The partitioned Ternary area (80° E–105° E, 35° N–50° N) was supposed to have multiple sources of Pu including the STS and LNTS besides the global fallout, which was characterized with slightly lower 240Pu/239Pu atom ratios (MED = 0.174) as well as elevated 239+240Pu concentrations (MED = 0.416 mBq/g). Meanwhile, the Binary area (35° N–45° N, 100° E–115° E) was considered to have received the extra contribution from the high-yield nuclear tests at the LNTS besides the global fallout, resulting in the highest 240Pu/239Pu atom ratios (MED = 0.200) across China. The remaining area was marked as the Unitary area, where it only received the exclusive contribution of global fallout. Furthermore, through the statistical analysis of the 240Pu/239Pu data in the Unitary area, we recommended a value of 0.186 ± 0.021 (AM ± SD) as a representative or area-specific 240Pu/239Pu atom ratio baseline to characterize the global fallout derived Pu in Chinese soils....
A constitutive model based on damage mechanics and statistical strength theory for sandstone under water-rock coupling is proposed and verified by laboratory tests and numerical tests. The damage mechanism of sandstone under the coupling action of water and force is clarified based on the microscopic test of sandstone under the coupling action of water and rock in this paper. The stress state of sandstone is determined by analyzing the results of laboratory tests. Based on the energy theory method, the strength criterion of sandstone under the interaction of water and rock is obtained, which is introduced into the statistical damage constitutive model of sandstone considering the interaction of water and rock; thus, a relatively perfect damage constitutive model of sandstone considering the interaction of water and rock is established. Finally, the influence of the number of cycles on the model parameters was further analyzed by analyzing the model parameters and the water-rock coupling test. Compared with the existing test results, the model established in this paper can perfectly reflect the deterioration characteristics of sandstone under the coupling action of water and rock....
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