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Rock burst is a major disaster in deep mining, where bursting liability is an important indicator of rock burst risk. This study therefore intends to explore the impact of microwave thermal shock on rocks with strong bursting liability by testing the microwave thermal shock and uniaxial compression of typical hard brittle sandstone and analyzing their physical and mechanical properties and the response of bursting liability indicators after microwave thermal shock. The research results show that: (1) After microwaving, the surface temperature of the sandstone continues to rise with the increase of thermal shock time, until it breaks at 150 s; (2) Microwave thermal shock has a significant effect on the structural damage of sandstone. After 120 s of microwaving, the longitudinal wave velocity and elastic modulus decrease by 15.12 % and 8 % respectively. The AE signal density increases at each stage of uniaxial compression, and the maximum absolute energy at the final destruction of sandstone decreases by 42.3 %; The dynamic failure time of rock increases by 259 %, the impact energy index decreases by 95 %, and the elastic energy index decreases by 92 %. This research offer references for efficient rock breaking in deep earth engineering and prevention and control of rock burst in resource mining.

This paper focuses on the differences in crowding perception among different types of passengers in trains, aiming to optimize passenger experience and improve the level of service of urban rail transit. Based on data from a passenger survey on the Beijing subway, this paper introduces the concept of Crowding Perception Threshold (CPT) and analyzes the principle of passenger spatiotemporal crowding. Considering factors such as gender, age, travel purpose, and standing density of passengers, the paper constructs a quantitative model of crowding perception using the ordered logit model and proposes a method for classifying the level of service accordingly. The study results indicate that the CPTs for all types of passengers range from 91.8% to 101.6%, with the females, elderly individuals, and noncommuters showing greater sensitivity to crowding. In the temporal dimension, all types of passengers have higher CPTs during peak hours than during off-peak hours, influenced by passengers' crowding expectations. In the spatial dimension, the level of service for most types of passengers is considered crowded at standing densities of 6-7pax/m[sup.2] during peak hours, while the level of service for all types of passengers is deemed to be very crowded at 8pax/m[sup.2], at which point additional passengers are not recommended., Author(s): Xia Lu [1]; Baohua Mao (corresponding author) [1]; Min Wang (corresponding author) [2,3]; Yixin Zhao [1]; Peining Tian [1] 1. Introduction In some cities in China, the issue of [...]

This study aims to tackle the problem of frequent coal-rock dynamic events caused by local stress concentration in deep mining working face under high static stress environment. Specifically, by taking the deep working face of Hongqinghe Mine located in Xinjie Mining Area as an example for analysisthis paper investigates the geological conditions of No. 3-1coal seam that are affected by the mining method and the coal rock dynamic disaster events occurred during mining; utilizes numerical simulation to simulate the mining stress field and energy field of the stope; analyzes the potential coal burst instability area and mechanism of coal burst gestation and catastrophe in the stope during the mining of the No. 3-1103 working face; probes into the sources of catastrophic stress and influencing factors of coal-rock disasters in dangerous areas, puts forward targeted prevention and control measures. Results show that: ① the roof strata structure, goaf and coal pillar are the key factors influencing coal burst in the stope during the mining of the No. 3-1103 working face; ② the simulation results indicatethe location and characteristics of the coal burst instability area in the stope of the No. 3-1103 working faces, as well as the simulation outlines 5 strong coal burst areas and 11 medium coal burst areas presented in the stope; ③ Measures are proposed for coal burst during mining from the perspective of cutting off the dynamic load source, reducing static load stress concentration, and blocking the transmission of high concentration stress. Detailed measures include implementing multi-source prevention and control in areas with high static or high static+dynamic loads, implement pre-pressure off-load measures prior to mining, and local risk relief and coal burst prevention and reduction treatments during mining.

Pharmaceuticals and personal care products (PPCPs) are found in wastewater, and thus, the environment. In this study, current knowledge about the occurrence and fate of PPCPs in aquatic systems-including wastewater treatment plants (WWTPs) and natural waters around the world-is critically reviewed to inform the state of the science and highlight existing knowledge gaps. Excretion by humans is the primary route of PPCPs entry into municipal wastewater systems, but significant contributions also occur through emissions from hospitals, PPCPs manufacturers, and agriculture. Abundance of PPCPs in raw wastewater is influenced by several factors, including the population density and demography served by WWTPs, presence of hospitals and drugs manufacturers in the sewershed, disease burden of the population served, local regulations, and climatic conditions. Based on the data obtained from WWTPs, analgesics, antibiotics, and stimulants (e.g., caffeine) are the most abundant PPCPs in raw wastewater. In conventional WWTPs, most removal of PPCPs occurs during secondary treatment, and overall removal exceeds 90% for treatable PPCPs. Regardless, the total PPCP mass discharged with effluent by an average WWTP into receiving waters (7.35-20,160 g/day) is still considerable, because potential adverse effects of some PPCPs (such as ibuprofen) on aquatic organisms occur within measured concentrations found in surface waters.