Study on the stability of waste rock filling in goaf based on dynamic comprehensive analysis method.

The restoration and treatment of underground voids have always posed significant challenges for constructing environmentally sustainable mines. To investigate the effectiveness of a combined approach involving waste rock filling and grouting roof filling as treatment methods to ensure safety and stability in mining voids, this study employed a comprehensive dynamic analysis approach. It specifically focused on an individual underground metal mine cavity by integrating numerical simulation analysis techniques with onsite displacement monitoring methods.

Modifying the Fiber Structure and Filtration Performance of Polyester Materials Based on Two Different Preparation Methods.

How to build a satisfactory indoor environment has become increasingly important. In this paper, the synthesis and improvement of the most widely used polyester materials in China were carried out based on two different preparation methods, and the structures and filtration performances were tested and analyzed. The results showed that a carbon black coating was wrapped on the surfaces of the new synthetic polyester filter fibers.

Concentration Characteristics and Correlations with Other Pollutants of Atmospheric Particulate Matter as Affected by Relevant Policies.

With the increase in global environmental pollution, it is important to understand the concentration characteristics and correlations with other pollutants of atmospheric particulate matter as affected by relevant policies. The data presented in this paper were obtained at monitoring stations in Xi'an, China, in the years from 2016 to 2020, and the spatial distribution characteristics of the mass and quantity concentrations of particulate matter in the atmosphere, as well as its correlation with other pollutants, were analyzed in depth. The results showed that the annual average concentrations of PM and PM decreased year by year from 2016 to 2020.

Comparison of the Application of Three Methods for the Determination of Outdoor PM Design Concentrations for Fresh Air Filtration Systems in China.

With the increasing popularity of fresh-air filtration systems, the methods of determining the outdoor PM design concentration have become more important. However, the monitoring of atmospheric fine particles in China started relatively late, and there are relatively few cities with complete data, with obvious regional differences, which led to many problems in the selection of air filters for fresh-air filtration systems. In this paper, three methods of determining outdoor PM design concentration were analyzed using the daily average concentration of PM in 31 provincial capital cities from 2016 to 2020.