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With the development of urbanization in China, the problem of urban public safety is becoming increasingly prominent. A scientific regional risk assessment of urban public safety can provide important support for risk warning and management systems. This study aims to introduce a comprehensive method to assess and manage regional risk factors of urban public safety. Taking regional risk assessment of urban public safety as the research object, and focusing on multiple sources of risk such as industry, infrastructure, traffic, and public places, this study provides a comprehensive and systematic classification of risks and identifies the characteristics of the various risk agents. The urban region is divided into three units: an industrial risk unit, an urban population-intensive unit, and an urban communal facilities unit. Then, a multi-agent index system for regional risk assessment in relation to urban public safety is established. Using the analytic hierarchy process, the entropy weight method, and multiple connection numbers, both static and dynamic analyses of regional risks in relation to urban public safety are undertaken and the regional risks in relation to urban public safety are predicted.

Supplemental material, sj-docx-1-eea-10.1177_01445987221077364 for Study on instability discriminating condition and permeability variation of triangle articulated structure in highly inclined goaf by Song Qin, Haifei Lin, Zongyong Wei and Wei Shen in Energy Exploration & Exploitation

Based on the characteristics of deformation and caving of overburden strata and the law of gas delivery, a solid-gas coupling physical simulation experimental platform was self-developed. The different problems which are studying on the law of relief gas with face advancing in lab will be solved. The experimental platform is used to research the rule of change of seepage velocity with face advancing. The result shows that change trend of seepage velocity with the face advancing which decreased first, then increased, later, decreased, increased again and finally kept unchanged

Coal and coal-bed methane are all valuable energy resource, if they can be extracted simultaneously and safely, the triple purposes of mine safety production, new energy resource supply and environment protection can be fulfilled. The coal-bed methane existing features of i°three high-lowi± are analyzed in China, it is obtained that the main degasification method is drawing relieved methane. Based on the analysis of formation and dynamic feature of mining fissure Elliptic Parabolic Zone, applying environmental fluid mechanics and the principle of gas transportation, the floating-diffusion process of relieved methane in mining fissure zone is explained, and the layout principle of relieved degasification system is obtained. The artificial diversion flow method of degasification roadway which fulfills the coal and methane simultaneous extraction is put forward by a coal mine in Yangquan, China. Such studies show that the paper can provide the theoretical base and technical support for safely simultaneous extraction of coal and methane.