Research on Water-Conducting Fractured Zone Height under the Condition of Large Mining Height in Yushen Mining Area, China

AbstractAccurately predicting the development height of the water-conducting fracture zone (HW) is imperative for safe mining in coal mines, in addition to the protection of water resources and the environment. At present, there are relatively few fine-scale zoning studies that specifically focus on predicting the HW under high-intensity mining conditions in western China. In view of this, this paper takes the Yushen mining area as an example, studies the relationship between the water-conducting fissure zone and coal seam mining height, coal seam mining depth, hard rock scale factor, and working face slope length, finally proposing a method to determine the development height of the HW based on multiple nonlinear regression models optimized using the entropy weight method (EWM-MNR). To compare the reliability of this model, random forest regression (RFR) and support vector machine regression (SVR) models were constructed for prediction. The findings of this study showed that the results of the EWM-MNR model were in better agreement with the measured values. Finally, the model was used to accurately predict the development height of the hydraulic conductivity fracture zone in the 112201 working face of the Xiaobaodang coal mine. The research results provide a theoretical reference for water damage control and mine ecological protection in the Yushen mine and other similar high-intensity mining areas

Sustainable supply chain management towards disruption and organizational ambidexterity:A data driven analysis

Balancing sustainability and disruption of supply chains requires organizational ambidexterity. Sustainable supply chains prioritize efficiency and economies of scale and may not have sufficient redundancy to withstand disruptive events. There is a developing body of literature that attempts to reconcile these two aspects. This study gives a data-driven literature review of sustainable supply chain management trends toward ambidexterity and disruption. The critical review reveals temporal trends and geographic distribution of literature. A hybrid of data-driven analysis approach based on content and bibliometric analyses, fuzzy Delphi method, entropy weight method, and fuzzy decision-making trial and evaluation laboratory is used on 273 keywords and 22 indicators obtained based on the experts’ evaluation. The most important indicators are identified as supply chain agility, supply chain coordination, supply chain finance, supply chain flexibility, supply chain resilience, and sustainability. The regions show different tendencies compared with others. Asia and Oceania, Latin America and the Caribbean, and Africa are the regions needs improvement, while Europe and North America show distinct apprehensions on supply chain network design. The main contribution of this review is the identification of the knowledge frontier, which then leads to a discussion of prospects for future studies and practical industry implementation

A Superior Self-Adhesive, Self-Healing, and Anti-Freezing Gel toward Flexible Sensor Applications in Extreme Conditions

As an important part of flexible wearable electronics, hydrogel sensors have aroused great interest. However, two serious issues, low self-healing efficiency and terrible environmental adaptability, have largely limited the development of hydrogel sensors. Herein, a versatile gel elastomer (P(HEA-AA)/PEI/Gly) is synthesized via introducing polyethylenimine (PEI), 2-hydroxyethyl acrylate (HEA), and acrylic acid (AA) into a glycerin/water binary solvent system, which exhibits high stretchability (1427% elongation), outstanding self-healing efficiency (95%), and exceptional low-temperature adaptability (−35 °C) as well as robust self-adhesion. Meanwhile, the assembled P(HEA-AA)/PEI/Gly gel sensor possesses reliable sensitivity, wide strain range, and long-term cycling stability, which can not only precisely monitor different mechanical deformations (stretching, twisting, and bending) but also specifically distinguish the human activities in the opposite direction. In particular, even in an extremely cold environment of −35 °C, the gel sensor still can withstand large mechanical damages caused by external factors and restore its sensing capability. This feature inspires us to construct a wearable communication device with a low-temperature self-healing function that can accurately deliver various valuable information to the receiver under extreme conditions, such as “Warn”, “Cold”, and “Dangerous”. This work provides a feasible method to construct excellent self-healing and temperature tolerant gel sensors and paves the way for versatile applications in electronic skin, artificial intelligence, and soft robotics

Study on surface movement and deformation law of the middle deep buried thick seam in sandy region

In order to study the surface movement and deformation law caused by the middle deep buried thick coal seam mining in northern Shaanxi Province, the first working face （112201 ｗｏｒｋｉｎｇ ｆａｃｅ） of Xiaobaodang Coal Mine which lies in the middle of the third phase planning area of Yushen Mining Area was taken as the research area. The surface movement and deformation characteristics, the movement deformation parameters and development laws of surface cracks caused by coal mining are obtained through the combination of observation station, GNSS observation station and theoretical analysis. The results show that: the maximum subsidence and the maximum subsidence coefficient were 3 840 mm and 0.66 respectively caused by mining of 112201 coal face. The duration of surface movement and deformation was about one and a half years. The start-up stage last 18 days, and the active stage last 110 days. Among the active stage, the surface movement and deformation are mainly concentrated in 43 days. The surface subsidence in the active stage was 91.4% of total subsidence value. The degree of development of surface crack induced by mining of 112201 coal face was weak. Relatively speaking, the development degree of surface cracks above the cut hole was greater than that above the trough, and the degree of the surface cracks above the goaf was weakest. The surface crack in the 112201 coal face was developed behind the mining position, and the width showed a “single peak” dynamic characteristic. There is coupling synchronization between the dynamic change characteristic and the velocity of surface subsidence