Numerical investigation and analysis of indoor gas explosion: A case study of “6·13” major gas explosion accident in Hubei Province,China

Taking the ' 6·13 ′ major gas explosion accident in Shiyan, Hubei Province, China as an example, three problems were studied in this work: (1)The determination of the volume of natural gas involved in the explosion; (2)The propagation process of shock wave inside the building and the damage evolution process of the accident-related building; (3)The overpressure and fragment injury to the person outside the building. Through the numerical simulation in ANSYS/LS-DYNA software, the volume of natural gas involved in the explosion is determined to be 10240 × 1400 × 400 cm (length × width × height) from three perspectives: the damage to the building, the distribution of overpressure inside the building, and the TNT equivalent of the explosion energy. The simulation results are in good line with the accident, which verifies the effectiveness of the scheme and the accuracy of the numerical model. Based on the reasonable filling scheme, the propagation process of shock waves inside the building, the damage evolution process of the building, and the injury ranges of overpressure and fragments outside the building are analyzed. It can be found that the propagation of shock waves in confined space is complex and variable. The explosion shock waves are first reflected and superimposed in the watercourse, resulting in pressure rise. At about 8ms, the shock waves rushed into the first-floor space of the building, and the maximum overpressure was about 0.56 MPa. At about 50 ms, the shock waves rushed into the second-floor space, and the maximum overpressure was about 0.139 MPa. The first and second-floor slabs and infilled walls were almost completely destroyed. The interior walls of the infilled walls are mainly collapsed, and the exterior walls are ejection around the building as the center. The peak displacement and peak velocity of the interior walls of each floor are about 15% of the exterior walls. The fragments which cause fragment injury mainly come from the retaining wall above the watercourse, the maximum velocity is about 89 m/s, and the maximum displacement is 8.9 m. The safety distance of fragment injury is about 8.8 m, while the safety distance of overpressure injury is about 4.6 m. The lethal distance of fragment injury is greater than that of overpressure injury. Compared with the distance between different damage levels of overpressure injury, the difference in fragment injury is small. Therefore, the safety assessment at the engineering level only needs to consider the safety distance of fragment injury. This study can provide suggestions for evaluating the damage of natural gas cloud explosions in confined spaces and is helpful for accident investigation and safety protection.     

微生物在土壤中迁移物化参数的确定

以甲基叔丁基醚高效降解菌Chryseobacterium sp.A-3为研究对象,对污染场地生物修复中微生物在土壤中迁移的重要相关物化参数做了详细的描述和实验研究,包括土壤物性参数以及微生物在土壤中的吸附等温参数、吸附动力学、有效扩散系数和生长项系数.结果表明,微生物在土壤中的吸附等温线可与Freundlich方程很好地拟合,相关性达到99.5%,指数常数为1.1,该指数常数在统计上与1差别不大,因此可以用线性方程来描述平衡吸附过程.实验测得该菌在砂质壤土中的平衡吸附系数为0.98 mL/g.滞膜理论能够预测土壤中微生物的动力学吸附行为,同时也说明吸附过程是可逆的,得到土壤中微生物吸附的动力学参数,即可逆吸附常数为0.004 s-1,可逆解吸常数为0.002 s-1.膜池理论与分形理论分析得到微生物在土壤中的扩散系数为3.66×10-6 cm2/s,有效扩散系数为5.18×10-7cm2/s.通过对微生物降解甲基叔丁基醚过程进行拟合得到微生物的最大比增长速率为0.01 h-1,基质半饱和常数为134 mg/L以及细胞得率为0.33.本研究所提出的微生物在土壤中物化参数的确定方法可普遍应用于实验室和现场的微生物...     

改性石墨电极对DNP废水的降解过程研究

使用自制改性石墨/PTFE气体扩散电极作为阴极,铁电极作为阳极,构成电-Fenton反应体系对2,4-二硝基苯酚废水进行处理。一定电解条件下,研究了D(N/P)、D(N/P/Cu)自制气体扩散阴极电极对2,4-二硝基苯酚废水的处理效果及处理过程废水中金属离子、电导率的变化情况。结果表明,电解60 min时D(N/P/Cu)电极对DNP的去除率达到80.9%,最大去除率比D(N/P)高22.43%。阴极电极中铜离子的掺入不仅提高了电解效率,而且也大大降低了铁阳极的消耗及铁泥的产生量。对D(N/P/Cu)电极电解后的沉淀底物进行了红外光谱分析,发现沉淀物中除了未被降解的DNP外还含有分解产生的小分子烷烃类、胺类等中间产物。通过SEM对改性石墨电极表面进行了观察,发现电极材料粘合牢固紧凑,表面分布许多微小气孔,其中在改性石墨中掺入铜离子的D(N/P/Cu)电极表面更加致密光滑。     

液化石油气球罐泄漏扩散的数值模拟

利用流体力学Fluent软件,对液化石油气球罐区泄漏扩散进行了数值模拟,主要研究不同风速和不同形状障碍物存在条件下扩散流场的变化规律。结果表明:风速影响扩散方向、距离、浓度以及扩散平衡时间;障碍物的存在改变了常规扩散轨迹、空腔区浓度积聚,且不同曲率的障碍物在介质扩散过程中所承受的外压不同。该研究结果对球罐区安全事故救援具有指导意义。     

建立典型化工区突发性大气污染事件预测预警软件系统的构想

本系统主要包括污染气象模型、大气扩散的数学模型的建立,利用地理信息系统(GIS)技术,按照污染事故发生的地理位置,将模型的数值解和GIS相结合,从而可以在时间和空间上对污染扩散进行分析,得到不同地点的污染物浓度和污染程度,获取受污染范围内的人口和周边单位等重要信息;从而预测污染事故对环境的影响程度和范围,为突发性环境污染事故的应急监测、现场救护和灾后评估提供科学依据。     

Spreading the News on Carbon Capture and Storage: A State-Level Comparison of US Media

Carbon capture and storage (CCS) has received abundant federal support in the USA as an energy technology to mitigate climate change, yet its position within the energy system remains uncertain. Because media play a significant role in shaping public conversations about science and technology, we analyzed media portrayal of CCS in newspapers from four strategically selected states. We grounded the analysis in Luhmann's theory of social functions, operationalized through the socio-political evaluation of energy deployment (SPEED) framework. Coverage emphasized economic, political/legal, and technical functions and focused on benefits, rather than risks of adoption. Although news coverage connected CCS with climate change, the connection was constrained by political/legal functions. Media responses to this constraint indicate how communication across multiple social functions may influence deployment of energy technologies.     

Safety Ⅱ学术思想的科学传播研究*

为全面了解Safety Ⅱ学术思想的传播情况,采集Web of Science数据库中284篇引用Safety Ⅱ学术著作的论文,采用科学计量和知识网络的方法,分析Safety Ⅱ学术思想的传播时间趋势、传播主体分布、传播领域与期刊以及传播的热点主题分布。研究结果表明:Safety Ⅱ学术思想在传播时间上呈线性增长趋势;核心传播区域为英格兰、美国、澳大利亚、挪威和意大利;核心传播机构为挪威斯塔万格大学、荷兰代尔夫特理工大学以及罗马第一大学;核心传播者为Saurin Tarcisio Abreu、Hollnagel Erik以及Patriarca Riccardo;Safety Ⅱ传播的核心领域为工业工程、运筹管理科学、人机工程学、应用心理学以及健康护理科学与服务等领域;Safety Ⅱ传播的主题为“韧性与功能共振”、“病患安全”、“事故与人的失误”、“安全与风险管理”、“社会技术系统与人的因素”以及“安全风险的评估”6大方向。研究结果对我国安全科学理论与实践的发展有重要作用。     

煤矿井下瓦斯突出危险性的模糊分析

基于模糊可能性理论建立了瓦斯突出危险性函数。应用模糊多元分析方法建立了瓦斯突出危险性分析模型,通过对各类确定与非确定信息的模糊综合分析,预测煤矿开采过程中瓦斯突出的危险性,并在生产中应用该模型取得了较好的效果。     

碱消解-P&T-GC-AFS法同时测定土壤中的甲基汞和乙基汞研究

建立了碱消解-吹扫捕集-气相色谱-原子荧光光谱法(P&T-GC-AFS)同时测定土壤中甲基汞和乙基汞的分析方法.样品在90℃条件下经氢氧化钾/甲醇消解2.5 h,调节pH为5.40,并丙基化衍生后,采用P&T-GC-AFS法测定.方法对甲基汞、乙基汞的线性相关系数分别为0.999 7、0.999 6,检出限分别为0.26、0.41 ng·g -1.在不同质量浓度水平上进行加标回收率实验,甲基汞、乙基汞的回收率分别为90.5%~93.3%、86.5%~89.6%.该方法样品前处理简单、检出限低,适合批量测定土壤中甲基汞和乙基汞.     

顶空固相微萃取-气相色谱-串联质谱法测定水中2,4,6-三氯酚

建立了顶空固相微萃取-气相色谱-串联质谱法(HS-SPME-GC-MS-MS)测定水中2,4,6-三氯酚的方法。优化条件下,在1. 00～50. 0μg/L质量浓度范围内线性响应良好(r~2=0. 999 1);检出限0. 224μg/L,测定下限0. 896μg/L;加标样相对标准偏差(RSD)为4. 15%～6. 24%;加标回收率为81. 0%～115%;单个样品检测总时间40 min。该方法萃取与气相色谱-串联质谱分析在线一步完成,操作简便、灵敏度高、抗干扰性强,适用于地表水、生活饮用水、工业废水等水体中2,4,6-三氯酚的检测。