Thermal runaway (TR) in lithium-ion battery electric vehicles is influenced by multiple risk factors. These factors do not act independently, and the evolution of risk remains uncertain. To examine this problem, we combined the Delphi method, Interpretive Structural Modeling (ISM), and Dynamic Bayesian Networks (DBN) in one framework. Twenty-one key risk nodes were identified from accident cases, published studies, standard documents, and expert consultation. The causal relationships among these nodes and their probability parameters were then determined. Second, the Delphi method identifies direct causal relationships and assigns probability parameters. To handle expert uncertainty, we quantify judgments using triangular fuzzy numbers and defuzzify them via the centroid method. ISM was used to construct the adjacency matrix and the reachability matrix. The analysis identified four layers in the risk system: the root layer, the intermediate conduction layer, the intermediate result layer, and the outcome layer. This step clarified the propagation path of thermal runaway risk. The hierarchical structure obtained from ISM was then used to build the DBN model. Dynamic probabilistic inference was then used to analyze how thermal runaway risk evolves from initial causes to final outcomes. The results show that high-nickel ternary batteries and frequent fast charging are important prior factors. At the early stage, the probabilities of single-cell thermal runaway and thermal propagation reach 83.3% and 70.4%, respectively. Dynamic inference further proves that early emergency power-off and rapid response significantly block risk propagation. These actions successfully keep the probability of vehicle fires, flashovers, or secondary accidents at a minimum. The framework is useful for source identification, propagation analysis, and dynamic prediction of thermal runaway risk in lithium-ion battery electric vehicles.

With the rapid development of hydrogen fuel cell vehicles (HFCVs), the risk of hydrogen leakage and explosion on highways urgently requires in-depth research. This study systematically analyzed the impact of leak aperture (2 mm, 4 mm, 10 mm), leakage volume (64 L, 128 L, 192 L), environmental wind speed (0-8 m/s), and obstacle layout on hydrogen diffusion and explosion consequences by constructing a three-dimensional highway accident model and integrating computational fluid dynamics (CFD) with the TNO Multi-Energy method. The results indicate that in an open environment, the greater the leak aperture and leakage volume, the lower the environmental wind speed, and the higher the density of obstacles, the more significant the increase in explosion risk. For instance, under conditions of a 10 mm aperture, 192 L leakage volume, and 0 m/s wind speed, the peak overpressure reaches 68.9 kPa, corresponding to a 90 % tympanic membrane rupture distance of 1.65 m. This study further proposes a three-tier emergency evacuation strategy (core danger zone <= 1.65 m, secondary risk zone 1.65-6.86 m, peripheral monitoring zone 6.86-15 m), which can provide a scientific basis for emergency response to hydrogen vehicle accidents on highways. The findings fill the gap in hydrogen safety assessment in open environments and are of great significance for promoting the large-scale application of hydrogen energy transportation.

This study examines a gas pipeline explosion in Songyuan City, Jilin, using FLACS (Flame Acceleration Simulator) simulations to analyze leakage and blast dynamics. Results were validated against official reports. Key findings show: (1) along the X-axis, temperature rises and falls faster with distance from ignition; (2) on the Z-axis, higher elevations show slower temperature growth; (3) denser obstacles delay temperature decline; (4) wind conditions accelerate peak temperature arrival upwind, where temperatures exceed downwind areas; (5) higher ambient temperatures slow initial temperature rise and result in lower final temperatures at greater distances; (6) vertical analysis shows reduced explosion temperatures at higher elevations. The simulation matches investigation reports, confirming FLACS' reliability for safety assessments in urban gas pipeline management. Results highlight how environmental factors significantly impact explosion characteristics, providing critical insights for risk mitigation in populated areas.

In this paper, the diffusion characteristics and laws of hydrogen leakage in confined spaces are investigated using a combination of numerical simulations and experiments, and a small-scale cube model (dimensions: 0.47 mx0.33 m x 0.20 m) is used. The effects of leak source location, obstacles, leak hole size and shape on hydrogen diffusion and concentration evolution were investigated. The results show that the top funnel is sprayed vertically downward, the diffusion velocity decreases rapidly under the blocking effect of air and buoyancy force, and the momentum of the airflow is exchanged. During the injection phase, the leaking gas is mainly subjected to strong buoyancy forces and the hydrogen concentration shows a stratification effect. When the injection stops, the concentration difference decreases and eventually the hydrogen concentration reaches a steady state. The obstacle model in turbulence (4.3%) increases the concentration difference by a factor of about three compared to the empty room model (1.7%), which seriously affects the diffusive behavior of hydrogen. The obstacle in laminar flow model (10.4%) has almost the same concentration difference as the empty room model (10.2%). Rectangular leakage holes have a greater initial kinetic energy and diffuse more widely and faster.

In this paper, a combination of experimental and numerical simulation is used to investigate the effects of ob-stacles and leakage hole shapes on the leakage diffusion pattern and hydrogen concentration. A small-size cubic geometry model of 0.47 m x 0.33 m x 0.20 m is used to calculate the concentration of the leakage model in the confined environment. The results show that the influence of the Q1-Turbulent Flow obstacle model on hydrogen leakage and diffusion is more serious than that of the Q2-Laminar Flow, the gas in the upper part of the model is easier to accumulate, the hydrogen concentration is higher, and it takes longer to finally reach a stable state. Rectangular leakage holes have a larger hydrogen diffusion range, faster diffusion rate, higher initial kinetic energy, and are more likely to exceed the lower flammability limit of hydrogen. Q1-Turbulent Flow obstacle modeling injection process, t = 0.3 s, the gas cloud just contacted the obstacle, initially spread along the obstacle. With the continuous leakage of hydrogen, a large amount of gas comes into contact with the obstacle, and at t = 0.5 s, the obstacle starts to block the normal diffusion of leaking hydrogen, causing initial kinetic energy loss under the effect of buoyancy and obstacle blocking, and the direction of motion of hydrogen changes. When t = 0.8 s, due to the blocking effect of the obstacle wall, aggregation and vortex area are generated. t = 1 s, the area of vortex area is further increased, at this time, the degree of danger is obviously higher than before, and it is very easy to asphyxiation, explosion and other accidents.

With the increasing popularity of hydrogen fuel cell vehicles (HFCV), the risk of hydrogen leakage is becoming increasingly prominent. The closed nature in the vehicle structure may lead to rapid accumulation of hydrogen in the cabin when a leak occurs, creating a high concentration that can threaten passengers' respiratory safety and even their lives, as well as potentially triggering an explosion accident. Therefore, this study focuses on hydrogen fuel cell vehicles (HFCVs) with a hydrogen storage pressure of 70 MPa, applying computational fluid dynamics (CFD) methods to simulate the diffusion of hydrogen leakage at different locations, and discusses the impact of leakage rates, leakage hole shapes, and ventilation conditions. This study reveals how hydrogen concentration and distribution change with time in the vehicle under different leakage scenarios, providing important theoretical support for improving the safety of HFCVs. The results indicate that hydrogen leaks at different positions lead to different concentration distributions. Specifically, leaks at position one can accumulate hydrogen between the driver and co-driver, increasing the flammable risks for the front seats. Leaks at position two gather around the seats and spread outward, with the area around the vehicle's roof edge prone to hydrogen accumulation. Leaks at position three, due to the confined space of the trunk, lead to a rapid increase in hydrogen concentration. Further analysis indicates that the higher the leakage rate, the faster the hydrogen diffuses, and the broader the range of concentration distribution becomes; the irregular rectangular shape of the leakage hole accelerates the diffusion speed of hydrogen in both horizontal and vertical directions, expanding the diffusion range. The location of the vent plays a significant role in controlling hydrogen diffusion under different leakage positions. At position one, the vent at the front of the car can effectively reduce the hydrogen concentration on the hood and driving position. At position two, the vents at the front and rear of the car can more rapidly decrease the hydrogen concentration inside the vehicle, reducing the time personnel are in danger. At position three, the vent at the rear can effectively promote the quick exhaust of hydrogen, lowering the concentration inside the car and reducing the risk of ignition.

Dangerous chemicals are widely present in various aspects of people's lives, but they often pose risks of leakage and explosion during transportation and storage, resulting in severe casualties and property damage. Firstly, this paper proposes a visualization method applicable to comprehensive failure consequences of hazardous chemical storage tanks. This method considers the toxic hazard range of chemical leaks and the blast overpressure injury range of leak clouds and visualizes the comprehensive failure consequences. Secondly, FLACS is employed to simulate a major leakage and explosion accident at Jinyu Petrochemical Co., Ltd. in Linyi City. The simulation reproduces the leakage and explosion processes and verifies the reliability of the simulation results. Finally, the proposed method is used to visualize the comprehensive failure consequences of this accident, providing comprehensive visual results. The method presented in this paper can serve as a theoretical reference for predicting the development of accidents and clarifying their consequences.

Based on the Jilin Songyuan gas pipeline accident, FLACS software was used to numerically simulate its leakage and explosion process in order to study the change law of the equivalent gas cloud volume of gas leakage diffusion under various influencing factors. The simulation results were compared and analyzed with the accident investigation report in order to ensure the accuracy of the simulation results. On this premise, the three primary influencing factors-the obstacle distribution technique, the ambient wind speed magnitude, and the ambient temperature-are varied in order to study the equivalent gas cloud volume variation features of the leaking gas cloud. The findings indicate a positive association between the maximum equivalent gas cloud volume of the leaking gas cloud and the density of the obstacle distribution. There is a positive correlation between ambient wind speed and the equivalent gas cloud volume when the ambient wind speed is less than 5.0 m/s, and a negative correlation between ambient wind speed and the equivalent gas cloud volume when the ambient wind speed is greater than or equal to 5.0 m/s. A drop in Q8 is proportionately increased by around 5% for every 10 °C increase in ambient temperature when the temperature is below room temperature. There is a positive association between ambient temperature and the equivalent gas cloud volume Q8. When the temperature is higher than room temperature, the drop in Q8 is correspondingly increased by about 3% for every 10 °C increase in ambient temperature.

This paper presents a simulation analysis of the explosions following an LPG leak and visualizes the consequences of the accident to reduce the consequences of the LPG leak explosion. Firstly, this paper proposes a CFD numerical simulation-based method for visualizing the consequences of LPG tanker failure. The method combines satellite maps and CFD numerical simulation data to visualize the consequences of LPG leaks and explosions, taking into account the influence of obstacles on the danger range of leaks and explosions; Secondly, this paper applies the method to a liquefied petroleum gas accident that occurred in the Wenling section of the Shenhai Expressway and performs CFD numerical simulation on the accident process and visualizes the consequences of the accident. Therefore, this method can provide a theoretical reference for the prior prevention of LPG accidents and the analysis of the consequences of accidents, as well as certain practical guidance instructive.

本文基于Pyrosim模拟高校学生宿舍楼4个不同着火点的火灾发展规律,研究温度、能见度、烟气层高度、CO浓度等参数对高校学生宿舍楼人员疏散的影响.模拟结果显示:着火点在房间内时,着火点房间和着火楼层走廊温度较高,CO浓度在着火点房间内快速达到致死浓度;着火点在楼梯转台下方时,整体温度较低,顶层的烟气层下降较快,300s时顶层楼梯道附近能见度已经小于5m,对疏散造成严重影响.此研究结果可为研究学生宿舍楼火灾发展规律及火灾应急疏散提供参考.

为了研究影响边坡稳定性的因素,采用实验与仿真模拟相结合的方法,通过对现场土样的剪切试验数据进行分析得出内摩擦角及粘聚力等参数,并将其与Geo-Studio软件模拟所得到的自然降雨工况下最小安全系数进行对比与分析,最后根据工程实际情况,提出针对提高边坡稳定性支护的方案:采用土钉支护方案,并将土钉数量设为1根时,坡面就可以达到稳定状态,安全系数也较之前大幅提高.

为研制矿山呼吸性粉尘浓度个体监测仪,采用MIE光散射方法,试制以红外线发光二极管作为光源的呼吸性粉尘浓度个体监测仪,该监测仪主要由气路部分、光路部分及电路部分组成.利用中国安全生产科学研究院自制的粉尘简易试验装置,在气体流量为2L/min、颗粒粒径不大于5 pm的条件下,研究试制仪器电压输出值和流入粉尘质量浓度二者的对应关系.结果表明:根据不同粉尘质量浓度下的输出电压数据,在0～300 mg/m3测量范围内,试制仪器输出电压值和粉尘浓度之间具有线性函数关系,说明呼吸性粉尘浓度个体监测仪是合理可行的;粉尘监测仪测试结果与比对仪器测量结果对比分析可知,测量误差最大为1.59％,满足粉尘检定规程要求..

随着经济全球化的快速发展及城市化进程的不断加快,城市燃气的应用在我国的大小城镇迅速发展,已成为城市建设中必不可少的基础设施之一.但与此同时,城市燃气爆炸事故的发生也给人民的生命安全以及国家财产造成了巨大的损失.基于此,首先介绍了城市燃气爆炸事故的特点;其次通过统计分析近5年内城市燃气爆炸事故的有关事故数据,找出了导致事故发生的主要原因;提出了目前城市燃气安全方面所存在的一些问题,并根据资料分析的结果做出了相应的研究展望.

针对当前"安全原理与安全管理学"课程教学内容重复性高、教学方法单一、考核方式简单等问题,本文从优化教学内容、丰富教学方法,改善考核方式等方面开展教学改革,可以有效地提升学生对课程的参与程度,充分调动了学生学习的积极性,进而取得良好的教学效果.

针对当前《安全检测与监控》课程缺乏授课经验、理论教学手段较为单一、实验教学条件有限等问题,从教材内容、教学方法、考核方式等方面开展改革,满足复合型、创新型安全工程专业人才培养要求.

翻转课堂的优势在于通过改变原有教学流程的顺序,实现知识传递的提前和知识内化的优化.工科院校可通过引入和推广翻转课堂教学模式,弥补传统教育的不足,培养学生自主学习和创新能力.在推广过程中,应冲破传统观念的束缚,开展相关培训,正确发挥微视频的效用,探索翻转课堂模式适用范围,并重构教学设计.

"电子工程设计"课程以小型温度测量与控制系统作为载体,建立了评价体系,设计了考核环节与指标体系的关联关系表 、针对6个考核环节的评分标准以及达成度的评价流程.根据评价体系,持续分析了近5年自动化专业学生的该课程达成度评价数据.通过增加结题答辩 、知识点考试等考核方式,使达成度较低的电子类产品分析 、调试与测试能力以及自动化领域复杂工程问题交流能力得到提高,有效地训练了学生电子系统的综合设计能力.

城市燃气管道由于受到腐蚀、外力破坏等原因导致破裂,造成燃气大量泄漏,从而发生中毒、火灾、爆炸等事故,管道泄漏后在空间某点形成的风险场是多个危险源共同作用形成的.基于经典场理论提出城市燃气管道系统泄漏事故的三维风险场概念,借用工程数学经典矢量场理论推导出城市燃气管道系统泄漏事故三维风险场的风险强度公式,并根据爆炸事故风险传播受风速等环境因素影响,在风险强度公式中考虑了环境因素修正系数K,使得理论推导尽可能与实际情况相符.最后通过实例计算表明,利用风险强度公式评估燃气管道泄漏事故在空间某点的风险与实际相符合,该方法将系统风险研究从二维平面转化到三维立体中,使得评估结果更为科学、合理.

The damaging effects of gas explosions on the area outside the mine pithead incur more accident risks on the auxiliary facilities and related personnel.Combined with typical gas explosion cases and based on computational fluid dynamics technology,this paper studied the gas explosion and its evolution process in coal mines,and investigated the distributive characteristics of the shock wave overpressure and temperature field outside the pithead.The study shows that the main hazard of gas explosion incurs on the area outside the pithead originates from the explosion shock wave along the horizontal direction,and its peak overpressure and spread range increase with the gas quantity while,however,its high temperature hazard on the horizontal direction is not obvious.The conclusions provides an essential referential basis for the site surface layout for coal mining and its related risk assessment and accident investigation.