In order to clarify the connotation and governance path of metaverse safety & security and further enrich the theory of metaverse safety & security, the concept of metaverse safety & security was put forward based on a large safety & security pattern, and the basic features of metaverse safety & security were analyzed. Moreover, the governance path of metaverse safety & security was proposed. The results show that metaverse safety & security refers to the state or ability of the metaverse to reshape spatial and temporal stability, social civilization advancement and human well-being enhancement from the influence of unfavorable factors, and it has eight basic characteristics, namely, relativity, complexity, vibration, extensiveness, immediacy, relevance, publicity, and multidimensionality. Metaverse safety & security governance should integrate the development and safety & security of the metaverse, adhere to the principle of joint consultation and sharing, build a "technology-rule-society" trinity of governance models, and strive to enhance the digital safety & security capacity of the metaverse.

In order to improve the construction of undergraduate curriculum settings in the field of safety engineering, a total of 68 outstanding undergraduate theses (designs) from 38 universities in 2021 were collected and organized in this study. CiteSpace software was used to perform cluster analysis on the keywords of the theses, and the current research topics of undergraduate theses (designs) were clarified. Subsequently, the industry background of safety engineering in the 38 universities was investigated, and the differences of curriculums between representative Chinese and foreign universities in safety-related disciplines were statistically analyzed. The results show that the high-frequency keywords in the 68 theses are mainly related to the following aspects: "numerical simulation", "disaster warning", "safety management system" and "resilience". Based on the investigation results of the industry background of universities, among the 68 theses(designs), the number of theses in the direction of public safety accounts for 45.6%, and the number of papers on mine safety accounts for 8.82%, but nearly 40% of the 38 universities take mine safety as a key service area, which showed that the research directions of safety disciplines theses has shifted from focus on industry safety to "general safety science". However, the characteristic curriculums still primarily focus on industry safety, with some repetition in the content of basic curriculums. Furthermore, there is a lack of numerical simulation curriculums. These factors make it difficult for the currently offered curriculums to support students in conducting their graduation projects. Additionally, compared with safety-related disciplines in foreign universities, it was found that the number of basic curriculums in safety engineering in China is relatively high, whereas the practical curriculums show the opposite condition.

In order to clarify the mechanism of safety and security incident causation from a safety and security intelligence perspective, and to consolidate the theoretical foundation for the investigation, analysis and prevention, and control of safety and security incidents from a safety and security intelligence perspective, research on safety and security incident causation model from a safety and security intelligence perspective was conducted. Firstly, according to the model for safety and security intelligence-safety and security behavior double loops, this paper analyzed the causes of safety and security incidents from a safety and security intelligence perspective. Secondly, the safety and security incident causation model from a safety and security intelligence perspective was constructed and explained. Finally, this paper analyzed the application of the safety and security incident causation model from a safety and security intelligence perspective with a safety and security incident on Line X of a city metro. The research shows that the safety and security incident causation model from a safety and security intelligence perspective is a safety and security incident causation system consisting of a safety and security intelligence loop and a safety and security behavior loop. According to this model, safety and security intelligence failures in the safety and security intelligence loop can lead to the disruption and collapse of the safety and security behavior loop of the system, resulting in a safety and security incident in the system.

To propose effective safety cognition strategies and reduce safety accident occurrence, it is urgent to investigate the safety cognition evolution process and characteristics of cavern constructors. Firstly, factors affecting safety cognition were identified based on a complex sociotechnical system and the 24Model, then a safety cognition index system of cavern constructors was proposed. Subsequently, the weight coefficient was calculated by the Super Decisions software. Then, system dynamic (SD) theory was used to determine the interrelationship between factors. SD numerical model was developed including organizational safety management and other three subsystems, and a cognitive correction mechanism based on safety investments was applied to the SD numerical model. Finally, numerical simulations and sensitive analysis were performed by the SD model based on actual engineering examples. The results indicated that the overall safety cognition of cavern constructors changed from a downward trend to an upward trend by increasing safety investments and exerting the role of cognitive correction mechanisms with project processes. Organizational safety management has the greatest influence on the safety cognition of carve constructors, which was consistent with the assumption of 24Model. Therefore, the scientific performance of the SD numerical model was validated.

In order to explore the mechanism of the influence of work underload on the risk perception ability of coal mine monitoring inspectors, boredom proneness and mind wandering were introduced as mediating variables to construct a chain mediation model of the four. A structured questionnaire was made with four scales: work underload, boredom proneness, mind wandering and risk perception. Quantitative studies were conducted on questionnaire samples from 263 coal mine monitoring inspectors, and the sample data were analyzed using Pearson correlation analysis and mediation effect tests. The results show that work underload has a direct negative effect on the risk perception ability of coal mine monitoring inspectors. Furthermore, work underload also affects risk perception through the independent mediating effects of boredom proneness and mind wandering, and the chain mediating effect of boredom proneness and mind wandering. Therefore, timely detection and intervention of work underload, boredom proneness and mind wandering of inspectors can effectively improve their risk perception ability and prevent accidents.

In order to address the inefficiencies in manually classifying and analyzing inspection records about civil aviation supervision, a dual-channel feature extraction short text classification model was proposed. The model combined data augmentation techniques and character-word vector fusion. The model aimed to tackle classification issues related to people, equipment and facilities, institutional procedures and institutional responsibilities in civil aviation supervised matters. In order to tackle the issue of class imbalance, data augmentation algorithms were employed to generate new samples by transforming the original texts, thereby balancing the sample sizes across different categories. The word vectors and character vectors were fused by combining them at the character level, resulting in character vectors that retain word-level features. These fused character vectors were then fed into TextCNN and BiLSTM for feature extraction at different dimensions. By extracting features from both local and global perspectives, this dual-channel approach aimed to capture comprehensive and effective information from the inspection records dataset in civil aviation regulatory matters. Experimental results on the civil aviation regulatory matter inspection record dataset demonstrate that the proposed model achieves an accuracy of 0.983 7 and an F₁ score of 0.983 6. Compared with some existing word embedding models and character embedding models, the accuracy is improved by 0.4%. Furthermore, when compared with commonly used single-channel models, the accuracy is increased by 3%, which validates the effectiveness and comprehensiveness of the features extracted by the dual-channel model.

In order to deeply analyze the influence of pedestrian panic on the efficiency of group evacuation under emergencies, this paper analyzed and constructed a quantitative model of pedestrian panic, which was composed of two parts: self-panic and panic propagation. First, the model considered factors such as detention time, local density, the distance between pedestrians and exits, the density of people around and the spread of pedestrian panic. Then it was introduced into the social force model for improvement and optimization, and verified the validity by comparing with the classical phenomenon. Finally, the simulation analysis was carried out using Anylogic software. The results show that the improved model can better reflect the evacuation movement characteristics of pedestrians in panic situations. A moderate panic, such as when the panic degree is less than 0.3, can accelerate the evacuation speed of the crowd. A high panic, such as when the panic value is greater than 0.3, can exacerbate the bottleneck phenomenon, and the so-called "fast is slow" phenomenon occurs, thus reducing the evacuation efficiency.

To effectively identify and assess different types of risk events in the risk zoo, and compare the difference of different risk metaphor events, based on theory of complex system thinking and vulnerability, risk metaphor events were identified and analyzed from 6 dimensions of risk certainty, universality, periodicity, stability, tolerance and reversibility. An assessment model of risk metaphor events was constructed based on the theory of the public safety triangle. The results show that through complex system thinking, we summarize and classify the general characteristics of risk metaphor events, and establish a multi-dimensional quantitative assessment model of risk metaphor events, which provides the application ideas and method logic for the control of risk metaphor events and ensure the scientific and reasonable establishment of risk metaphor events. Finally, the 4P (Prohibit, Suspend, Postpone, Prevent) strategy of risk prevention is proposed for the different cognitive characteristics of risk metaphor events, which provides a reference for organizations to carry out risk event control.

In order to cultivate a good safety culture in the operation stage of the nuclear power plant, the evaluation index system of safety culture in the operation stage of the nuclear power plant was constructed by analyzing the operation characteristics of the nuclear power plant and summarizing the existing evaluation index system and evaluation model, which was divided into four levels: values, behavior, system and environment, and subdivided into 13 secondary indicators and 61 tertiary indicators. On this basis, considering the non-independence and possible mutual influence between indicators, a comprehensive method based on DEMATEL and ANP was proposed to determine the weight of the index system. The results show that this method can get the evaluation index weight of nuclear safety culture by combining the survey data, and identify that the key to improving nuclear safety culture lies in the safety awareness of decision-makers and setting an example, which provides guidance for the cultivation of safety culture in the operation stage of nuclear power plants.

In order to effectively prevent and control the key safety risks in subway shield tunneling construction and accurately judge which risk coupling scenarios were significant ones leading to accidents, an improved N-K model was proposed to study the coupling effect of safety risks in subway shield tunneling. The key safety risks of subway shield tunneling were identified by comprehensively using literature research, accident case analysis and expert interview. Based on the N-K model, a new coupling analysis model of subway shield tunneling safety risk was proposed, and the applicability of the model was verified by a safety accident case. The results show that the list of key safety risk factors of subway shield tunneling is obtained, including 4 first-level risk factors (i.e., personnel-type, equipment-type, environment-type and management-type safety risks) and 21 second-level risk factors. The safety risk value of subway shield tunneling construction increases with the increase of coupling factors. Safety risk coupling values with four factors are the highest, followed by the coupling values of three factors, and safety risk coupling values with two factors are the lowest. Coupling scenarios with workers' low safety awareness and machine failure participating are more susceptible to safety accidents.

In order to improve the economic benefits of coal mining enterprises and reasonable arrangement of various safety inputs, a model to solve the correlation between indicators was constructed. Firstly, the influencing factors of economic benefits based on safety investment were analyzed, and a set of scientific and reasonable structural index systems was constructed on this basis. Secondly, the entropy weight method was used to determine the weight of each index. Then, in view of the correlation between indicators, based on the safety input structure, the entropy weight-Choquet fuzzy integral model based on a 2-additive fuzzy measure was introduced to calculate the economic benefit evaluation value. Finally, a coal mine was selected for empirical analysis to verify the feasibility and effectiveness of the constructed model. The results show that the constructed model is more reliable than technique for order preference by similarity to an ideal solution(TOPSIS) method. This model can take into account the mutual influence and correlation between indicators and obtain more accurate and scientific evaluation results.

The purpose of this research is to clarify the research progress of the theory and technology of pedestrian abnormal behavior recognition in public places. Firstly, with the help of China National Knowledge Infrastructure (CNKI) and the Web of Science (WOS), a broad definition and universal characteristics of abnormal pedestrian behavior in public places were given. The existing research results related to abnormal behaviors were divided into three categories: harmful behaviors, dissociable behaviors and violations. Then, from the perspective of data and technological foundations, the existing abnormal behavior recognition methods were divided into four categories: artificial design, human skeleton, Red Geen Blue(RGB) images and wearable sensors. Secondly, this study sorted out the abnormal behavior datasets of mainstream populations both domestically and internationally, and analyzed the performance of relevant algorithms on the datasets. Finally, the limitations of existing research methods in available datasets and data fusion detection were summarized, and future research directions and optimization suggestions were provided. The results indicate that these four types of abnormal behavior recognition methods have their own advantages and disadvantages. It is necessary to construct a diversified, well-defined and high-quality international benchmark dataset of abnormal behaviors among the crowd. Future research should focus on robust and accurate methods, models, and algorithms for identifying abnormal behaviors, explore multi-dimensional data fusion complementary detection methods, improve the application scenario consistency and adaptability of the theoretical results of abnormal behavior recognition, and eventually enhance the level of public place crowd safety governance.

A comprehensive database of MWSA was established to facilitate the data management to reduce the frequency and severity of accidents in China. From 2010 to 2022, a total of 278 records, supervised by the State Council Security Committee, were collected and stored in the MWSA database. The distribution of accident characteristics was explored for the dimensions of accident time, space, industry and type, which were examined in this study. Using a comprehensive quantitative index, a quantile regression model was developed to identify factors that significantly influenced accident severity. The results show that in terms of spatial and temporal distribution, the number of accidents and deaths from June to September is at the peak, and the number of accidents and deaths on sunny days (7:00-18:00) accounts for as much as two-thirds. There are fewer accident records in Beijing, Tianjin, Jiangsu, Zhejiang, Shanghai and Fujian. Explosions and vehicle injuries notably stand out as the primary accident types. At a significance level of 0.05, the accident severity is correlated with various factors, including accident type, date, season, sunlight, weather, average temperature, company staff size and company establishment time. Weather and average temperature emerge as pivotal factors influencing low-severity accidents. Moreover, enterprises with less than 100 employees are more prone to severe accidents.

In order to explore the spatial and temporal evolution characteristics of fire, economy and environment, based on the data of fire, economy and environment in China from 2000 to 2019, a fire-economy-environment coupling coordination model was established to study the coupling development level of fire, economy and environment system. Combined with ESDA method, the spatial and temporal evolution characteristics and aggregation of each subsystem in 31 provinces were studied, and the spatial correlation analysis of fire, economy and environment was carried out based on Moran 'I test. The research shows that the comprehensive development of fire, economy and environment has been well coupled from 2000 to 2019. From the time dimension, the coupling degree and coordination degree showed an upward trend from 2000 to 2019. The coupling degree was affected by the fire comprehensive score, and the coordination degree was affected by the economic subsystem. From the spatial dimension, economic development is the main factor affecting the coupling coordination degree of 31 provinces. From the analysis of the spatial and temporal evolution of the coupling relationship, the provincial coupling degree is aggregated with time, and the coupling coordination degree is random in spatial aggregation. The different effects of fire, economy and environment on coupling coordination lead to different coordination types and spatial aggregation states.

In order to reduce the risk of fire and explosion caused by the anthraquinone process for preparing hydrogen peroxide, a risk assessment was carried out for the extraction and purification process, which is a more hazardous process in the preparation of hydrogen peroxide by anthraquinone process. Firstly, hazard sources of this process were analysed and a fault tree model was established through Freefta software. On the basis of this fault tree model, a dynamic Bayesian network model was drawn using GeNIe software. Secondly, expert scoring method and fuzzy analysis method were used to calculate prior probabilities of basic events in the model, and GeNIe software was used to calculate posterior probabilities of basic events in the model under the set preconditions. Eventually, by comparing change range between prior and posterior probabilities, important basic events were determined, hazard sources causing fire and explosion were revealed, and emergency response technologies were proposed. The results show that four major hazard sources, including pollution caused by degradation products and impurities, generation and increase of side reactions in process, catalyst failure and active chemical properties of hydrogen peroxide, have great impact on fire and explosion during extraction and purification process. It is more effective to develop emergency response technologies for important hazard sources from the perspective of preventing fire spread and liquid evacuation.

In order to understand the influences of personality traits behind drivers' unsafe driving behavior, relevant studies on the relationship between personality traits and driving behavior at home and abroad since 2000 were reviewed. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) standard, 17 688 articles were retrieved from well-known domestic and foreign databases. After removing 3 160 duplicate articles, 14 263 irrelevant articles and 198 non-excellent articles, 67 excellent articles were finally included in this study. The relationships between different personality traits and unsafe driving behavior in these articles were summarized and sorted out. The results show that the five personality dimensions of the Big Five personality have different relationships with driving behavior. While sensation-seeking and impulsivity are both strong predictors of unsafe driving behavior, the latter has a stronger predictive ability. The direct predictive ability of driving anger on unsafe driving behavior is not strong. Additionally, factors such as normlessness, trait anxiety, altruism and narcissism have influence on unsafe driving behavior, although there is limited research on these. Furthermore, attachment, trait emotional intelligence, collectivism and abnormal personality traits need more tests. Some research results from Chinese samples diverge from the broader body of research, suggesting a need for cross-cultural studies.

In order to improve the safety efficiency of heavy construction machinery installation and lifting operation and improve the visibility of installation and lifting operation personnel, a multi-agent visual accessibility BIM simulation method based on the visual cone method was proposed. The multi-agent visual task of the heavy construction machinery was obtained through the decomposition of the visual task of heavy construction machinery. Taking the installation and dismantling operation of the wk-35 electric shovel as the research object, the multi-agent visual task of hoisting driver, signal operator and cable operator was analyzed, and the multi-agent visual BIM simulation scene of installation, dismantling and hoisting operation was constructed by using Computer Aided Three-dimensional Interactive Application (CATIA) human factor simulation module. The visual cone method was used to calculate the multi-agent visual accessibility value in the process of installation and lifting. The process parameters of the BIM model were adjusted, the trend of multi-agent vision was deduced, and the multi-agent visual accessibility of installation, disassembly and hoisting was evaluated. The simulation results show that the visual accessibility of the lifting driver is poor in the process of lifting and descending, but good in the process of translation. The position of the signal operator and cable man is closely related to their visual accessibility. The visual accessibility of the signal operator is best when the visual field of view just covers the lifting driver and cable man. The cable man needs to constantly adjust his position to achieve the best visual accessibility.

The double prevention mechanism was a widely used risk control system in hazardous chemical fields in China. However, the theoretical framework at underlying and operational levels was missing. Especially, there was a lack of RCA results to guide double prevention. Therefore, VPSB model was proposed by integrating primary-secondary barrier theory and ECF analysis technology. Furthermore, ECF as a typical RCA method represented the causal of a catastrophic event composed of specific primary-secondary barrier failure modes, providing a visualized diagram for the VPSB model. The model was used to identify hazards and RCA for a typical accident scenario in the Texas explosion of British Petroleum(BP) company. Moreover, the failure modes of double prevention related to management measures were investigated. The comparisons of investigation results between the U.S. Chemical Safety Board (CSB) and BP indicated that people's unsafe actions were taken as the direct cause to carry out in-depth cause analysis. Moreover, the focus was human management, and the failure of the safety supervisors and irregular operations of the operators were macroscopically summarized as the root causes. However, the VPSB model focused on near-miss and the process of major accident hazards, and detailed sub-barrier failure modes were used to highlight the fundamental problems of management systems. Specifically, mechanical integrity management had the largest number of problems because management measures were not conducted as required. This study can provide rectification directions and operability recommendations for enterprises to optimize the relevant work content of the double prevention mechanism.

In order to solve the problems such as the danger, the integrity of the train structure and the safety of personnel when the high-speed train was operated in a low-vacuum tunnel, the temperature attenuation characteristics of the high-speed train compartment in a low-vacuum tunnel in a fire were explored by numerical simulation. Then the temperature distribution inside the adjacent carriages was analyzed. Finally, the distribution characteristics of the maximum temperature inside the burning carriage were studied. The results show that the temperature of the burning carriage and adjacent carriage roof decreases exponentially along the longitudinal direction. In adjacent compartments, the power has an effect on temperature attenuation. At low fire source power (0.3-0.6 MW), the high temperature smoke spread is relatively weak, and passengers in the adjacent carriages are relatively safe. At medium source power (0.7-1.1 MW), the high temperature smoke spreading is significant, and the temperature abrupt point appears due to the influence of carriage wall and door. At high fire source power (1.2-1.5 MW), the heat plume intensity is higher, and high temperature smoke spread is relatively less affected by carriage wall and door, and temperature spreading trend in the connecting part of carriage is basically the same as that in the adjacent carriage. The maximum temperature in the carriage is related to power of fire source and distance from fire source to the ceiling, and there is a linear relationship.

In order to investigate the mechanical response of sandstone under cyclic stress from the energy perspective, the loading and unloading tests conducted along three cyclic paths which included an incremental step-by-step increase in initial peak stress at 10 MPa, an incremental step-by-step increase in initial peak stress at 80 MPa, and a constant peak stress maintained at 100 MPa. Subsequently, we analyzed the evolution characteristics of each energy component of sandstone based on the stress-strain curve and energy calculation results, taking into account the number of cycles and peak stress. The results show that as the number of cycles and peak stress increase, the hysteresis loop migrated to the direction of strain increase obviously only in the second cycle at the initial peak stress of 80 and 100 MPa. Different stress cycle paths make the unit volume dissipated energy shows different stage evolution characteristics. The energy values of sandstone change from a quadratic to a linear growth law as the peak stress increases in the hierarchical cyclic loading and unloading way, while in the constant amplitude cyclic loading and unloading way with the peak stress constant at 100 MPa, the unit volume energy and unit volume elastic energy of sandstone show an open downward quadratic decrease trend and the unit volume dissipative energy shows an exponential decrease trend. The effect of cyclic paths on the energy of sandstone in different stress ranges is quite different. In a comparison of the single and the hierarchical cyclic loading and unloading way, the energy difference is less than 10% when the peak stress is 80 MPa, while the energy difference is 22.74%-62.58% when the peak stress is 100 MPa.

To solve the problem of heat damage caused by the continuous extension of coal mining depth, and to reveal the distribution characteristics of the temperature field in the deep-shaft roadway, five kinds of mining thermal insulation materials were selected to carry out the study of thermal insulation and cooling in the deep-shaft roadway, to analyze the effects of different thicknesses of the thermal insulation layer and different initial temperatures of the peripheral rock on the temperature field of the peripheral rock, the radius of the heat-regulating circle, and the temperature change of the wind flow in the roadway, and to analyze the evolution characteristics of the peripheral rock temperature field in the vicinity of the thermal insulation layer. The results show that foam heat-insulating concrete has the best heat-insulating performance and the lowest economic cost. The selection of lower thermal conductivity of the insulation layer helps to improve the thermal insulation effect of the insulation layer, and 5-10 cm is the best thickness of insulation layer, temperature field is consistent with the spatial distribution of peripheral rock layer, anchor spraying layer, and insulation layer, thermal conductivity of insulation material is negatively correlated with the tunnel peripheral rock temperature gradient, thickness of insulation layer, and temperature of the original rock are positively correlated with the tunnel peripheral rock temperature gradient, and thickness and temperature of insulation layer have a significant influence on radius of heat-regulating circle. Temperature has a certain degree of influence on radius of heat-regulating circle, compared with the roadway without a heat-insulating layer, roadway heat-insulating effect of cooling effect is significant.

In order to explore the response mechanism of spontaneous combustion of underground coal and surface carbon flux under complex conditions, the surface CO₂ flux, soil temperature, fissure, environmental wind velocity and soil humidity in Fuxin Haizhou open-pit mine were monitored for a long time. Field tests, data analysis and other methods were applied to study the correlation between the underground coal spontaneous combustion and surface CO₂ flux. The influence of surface fissure, environmental wind velocity and soil humidity on the response mechanism of underground coal spontaneous combustion-surface carbon flux were analyzed. The results show that underground coal combustion is the fundamental factor triggering the abnormal surface carbon flux response. The surface CO₂ flux is positively correlated with the surface soil temperature distribution. Surface fissure is the main factor affecting the surface CO₂ flux distribution. The environmental wind speed is positively correlated with the surface CO₂ flux. The surface CO₂ flux response is generally not affected by soil humidity, but it is greatly affected by rainfall.

To improve coalbed methane extraction efficiency in deep mines, a high-flow sealing hole grouting material was developed using superfine cement as the base material to overcome issues of commonly used high polymer sealed materials such as high cost and flammable, low permeability of ordinary cement materials, and insufficient strength of paste materials such as fly ash. The hydration mechanism of the developed high-flow sealing grouting material was explored by an experimental study on the material's mechanical properties, combined with the measurements by scanning electron microscope(SEM)and X-ray diffraction(XRD). The results indicated that a large amount of calcium silicate hydrate (C-S-H) gel and ettringite (AFt) crystals were generated in the high-flow sealing grouting material during the initial phase of hydration. Furthermore, the gel particles of hydration products filled the pores of the material with the hydration reaction. Compared to commonly used cement sealing grouting material, the hydration reaction of the developed material was much faster and more complete, and the overall structure was more denser. Moreover, the compressive strength was increased by 3.68%. Therefore, the developed high-flow sealing hole grouting material can maintain the stability of gas extraction boreholes and improve gas extraction efficiency.

Deep mining faces high temperature and pressure environments. In order to understand the adsorption gas characteristics of deep coal bodies, an isothermal adsorption experiment was conducted to study the coal's adsorption characteristics under different temperature and pressure conditions. The experiment examined both macro and micro perspectives of the coal's adsorption behavior, molecular dynamics isothermal adsorption simulation and theoretical analysis. The research results are as follows. When the gas pressure is low, the difference between the absolute adsorption capacity and the excess adsorption capacity is not significant at different temperatures. When the gas pressure is high, the difference between the absolute adsorption capacity and the excess adsorption capacity increases with the increase in temperature. In the process of gas pressure increasing from 0 to 20 MPa, the amount of gas adsorbed by coal is divided into three stages. The growth pattern consists of a rapid increase during the initial stage, followed by short-term stability in the middle stage, and a gradual decline in the later stage. The equal adsorption heat and adsorption capacity of coal meet the exponential function relationship. The temperature-pressure adsorption model based on the equivalent adsorption heat deduction can predict the quantity of isothermal adsorption gas under any temperature and pressure conditions, and the relative error between the measured and predicted values is 10%.

To mitigate the long-term impact of horizontal loads (such as wind, waves and currents) on offshore wind turbines, a finite element model for the ultimate bearing capacity of heterogeneous clay single-pile foundations was developed using ABAQUS software. Temperature was employed as a virtual variable to reflect the relationship between shear strength of heterogeneous soil and depth. The Model Change technique was employed to achieve geostatic equilibrium, and the obtained results regarding the variation in horizontal loads on single-pile foundations were compared with centrifuge test outcomes to validate accuracy. Combining the failure modes of soil under horizontal ultimate loads for both rigid and rigid-flexible piles, the influence of parameters such as aspect ratio, soil elastic modulus coefficient and pile-soil friction coefficient on the horizontal ultimate bearing capacity of single pile foundations was analyzed. The findings indicate that with an increase in pile embedment depth, the pile transitions from a rigid state to a rigid-flexible state, and the soil failure mode shifts from wedge and rotational failure to wedge, full-flow and rotational failure. The soil elastic modulus coefficient has a minor impact on the horizontal ultimate bearing capacity of single-pile foundations, while the aspect ratio and pile-soil friction coefficient exert a significant influence.

In order to explore the influence of initiation sequence on the crushing effect of open steps and the surrounding environment, the LS-DYNA simulation software was used to calculate the step blasting model under different initiation sequences. First, the physical and mechanical characteristics of the model under different initiation orders were analyzed. Then, the field test was conducted to verify the simulation results and study the influence of the initiation sequence on the blasting vibration strength and rock crushing degree. The results show that the stacking effect, which changes the stress wave, shows the breaking effect and blasting vibration strength. The hole-by-hole blasting technology can effectively reduce the blasting vibration so as to reduce the adverse effects on the surrounding environment, but the rock-crushing effect is not ideal; the rock passing rate is 81.52%. Compared with the hole-by-hole blasting, the passing rate of wave sequential blasting gravel is increased by 11.68%, and the amount of single-hole collapse is increased by 16.8% when the hole net parameter is increased to 3 m×7 m, which effectively reduces the explosive consumption and reduces the comprehensive cost. However, it produces a large blasting vibration strength, which needs to pay attention to the impact on the surrounding environment.

To explore the enhanced permeability of gas-containing coal seams and improve extraction efficiency, high-pressure gas fracturing tests under different impact directions were performed by a self-developed true triaxial high-pressure gas impact rock fracturing test system. The test variable was the angle between gas impact direction and maximum horizontal principal stress. High-pressure gas impact tests were performed under the actions of three triaxial stress, and rock fracture morphology and acoustic emission response were obtained at angles between the impact direction and the maximum horizontal principal stress of 0, 30, 45, 60, and 90°. The results indicated that the rock fracturing process caused by high-pressure gas presented five significant stages including the impact crack initiation stage, air pressure rising stage, crack propagation stage, air pressure stabilization stage, and pressure attenuation stage; High-pressure gas impact caused vertical and horizontal cracks. Vertical cracks were deflected, and the deflection angle increased with the increment of the jet angle. Moreover, the crack deflection points gradually moved away from the drilling hole, and the horizontal fracture surface took on a shape of low in the middle and high in surrounding areas. The maximum gas pressure increased with the angle between the jet direction and the maximum principal stress, and the peak pressure represented a linear increment from 0 to 90°; The acoustic emission signals analysis indicated that rock impact failure was primarily caused by tensile failure and supplemented by shear failure. However, as the jet angle increased, it gradually became a tensile-shear composite failure dominated by shear failure.

To deeply explore whether ride-hailing services directly affect road traffic crashes and whether they indirectly affect road traffic crashes by changing the usage of buses and private cars, based on panel data from 114 cities in China from 2005-2017, the multi-period DID method and the causal steps method are used to estimate the impact mechanism of ride-hailing services on road traffic crashes. The results show that the entry of ride-hailing services increases road traffic crashes by 5.6%, and this conclusion still holds after performing robustness tests such as parallel trend and Propensity Score Matching-DID. Ride-hailing services significantly reduce public transit usage by about 19.3%, thus indirectly increasing road traffic crashes by 0.71%, which indicates that public transit usage plays a mediating effect. Ride-hailing services significantly increase private car usage by 5%, thus indirectly increasing road traffic crashes by 0.14%, which indicates that private car usage plays a mediating effect. The decrease in public transit usage is an important reason why ride-hailing services indirectly increase road traffic crashes. Government departments should strengthen the regulation of ride-hailing services, while encouraging the synergistic development of ride-hailing services and public transit.

In order to achieve the goal of cost reduction and efficiency enhancement in emergency logistics, the comprehensive capabilities of emergency logistics suppliers were evaluated from the perspective of suppliers by utilizing the Cloud TOPSIS. Based on the characteristics of emergency logistics, a comprehensive evaluation index system for emergency logistics suppliers was constructed from five aspects: emergency response capability, material quality, cost control, emergency response flexibility, and internal and external conditions of the enterprise. Drawing on the ideas of game theory, the objective weights obtained by the improved entropy weight method and the subjective weights obtained by Analytic Hierarchy Process (AHP) were taken as game opponents to determine the optimal combination of weights. The cloud model was used to solve for the decision-making cloud of indicators and the weighted cloud for the fuzzy qualitative evaluation semantics quantification of suppliers. Finally, using the TOPSIS method, the positive and negative ideal solution sets were constructed, and the relative closeness to these ideal solutions was determined by calculating the distance of alternative solutions, thus identifying the optimal alternative. Research indicates that the Indicator Decision Cloud can accurately quantify evaluative language, and the results of the Cloud-TOPSIS method are more reasonable. In the ranking of suppliers' relative closeness, the difference between the best and worst calculated by the Cloud-TOPSIS method is 0.331 5, while for the TOPSIS method, it is 0.088 2, with a difference of 0.243 3. This suggests that the evaluation results of the Cloud-TOPSIS method have a greater degree of differentiation, which can more intuitively assist decision-makers in making optimal choices.

In order to reduce the casualties and property losses and improve the emergency rescue capability in coal and gas outburst accidents, an SSA optimized SVM was proposed to evaluate the emergency rescue capability of coal and gas outburst accidents. First, according to relevant literature and research reports, four first-level indicators, including emergency prevention ability, emergency preparedness ability, emergency response ability and recovery and rehabilitation ability, were constructed. These indicators were further subdivided into 18 second-level indicators, and the score data of each indicator was used as the model training dataset. Then, the network analytic Hierarchy process (ANP) and entropy weight method (EWM) were used to determine the subjective and objective weights of each evaluation indicator under the mutual influence, and the Lagrange function was used to merge the weights to obtain the optimal weights. SSA optimized the radial basis parameters g and penalty factor C of SVM. The result of optimal weight calculation was used as the input of the SSA-SVM model, and the expected value was used as the output for linear regression prediction. Finally, taking a mine in Hebei Province as an example, the prediction results of the SSA-SVM model was compared with the traditional SVM, particle swarm optimization algorithm (PSO) optimization SVM and Whale optimization algorithm (WOA) optimization SVM, and the predicted results and the expected values were analyzed. The results show that the prediction results of the SSA-SVM model are consistent with the reality, and the average absolute error decreases by 8.04%, 5.15% and 4.82%, respectively, compared with other models, which proves the superiority of the proposed model. This model can be applied to the evaluation of the emergency rescue ability of coal and gas outburst accidents in actual mines.

The association between MHO and HUA and whether liver enzyme abnormalities could modify this association were studied. The cross-sectional study was conducted using 6,868 steelworkers in Hebei Iron and Steel Company who participated in occupational medical examinations as the study population. The data were analyzed using logistic regression models and interaction effect model. The results show that, in a multiple adjusted logistic model, the risk of HUA is increased 2.13-fold (odds ratio (OR)=2.13, 95% confidence interval (CI): 1.08-4.21) for metabolically healthy generalized obesity (MHGO). The risk of HUA is increased 2.25-fold (OR=2.25,95%CI: 1.14-4.45) for metabolically healthy abdominal obesity (MHAO). In stratified analysis, in the group with elevated liver enzymes, the prevalence of HUA in steelworkers with MHO(MHGO and MHAO) is significantly higher than that in the group with normal liver enzymes, and the interaction between obesity phenotypes and liver enzyme levels has a statistically significant effect on HUA (P<0.05). MHO is associated with a high prevalence of HUA. Liver enzyme levels may alter the relationship between MHO and HUA.

In order to analyze the content characteristics of international occupational health policies and promote the high-quality development of China's occupational health career, the occupational health policy texts of five countries, namely China, the United States, Japan, Australia, and Sweden, were taken as the research object. Relying on theory of policy tools and PMC index model, a quantitative analysis of the occupational health policies of the five countries was conducted under the international comparative perspective, and suggestions for optimizing China's occupational health policies were then put forward. The study shows that the five countries tend to shape the macro-environment and human and material resources of occupational health governance through environmental and supply-side tools and neglect the pulling role of demand-side tools. Compared with other countries, China has an excellent performance in terms of policy nature, policy recipients, policy focus, and incentives and constraints, and there is still some room for development in terms of policy effectiveness, policy perspectives, and policy subjects. Enhanced comprehension of the issue concerning the imbalanced allocation of occupational health policy tools is imperative. In light of the intricate and dynamic characteristics inherent in managing occupational health for workers, the imperative lies in providing enhanced guidance and support, particularly to those susceptible to mental health hazards.