Prediction of minimum ignition energy of aerosols using flame kernel modeling combined with flame front propagation theory

Flammable aerosols have created many fire and explosion hazards in the process industry, but the flammability of aerosols has not been fully understood. The minimum ignition energy has been widely used as an indicator for flammability of combustible mixtures, but the amount of experimental data on the minimum ignition energy of aerosols is very limited. In this work, the minimum ignition energy of tetralin aerosols is predicted using an integrated model. The model applies the flame front propagation theory in aerosol systems to the growth of the flame kernel, which was created during the spark discharge in the ignition process. The aerosol minimum ignition energy was defined as the minimum level of energy in the initial flame kernel to maintain the kernel temperature above the minimum ignition temperature of 1073 K specific for tetralin aerosols during the kernel growth. The minimum ignition energy obtained in the model is influenced by the fuel-air equivalence ratio and the size of the aerosol droplets. For tetralin aerosols of 40 μm diameter, E_min decreases significantly from 0.32 mJ to 4.3 × 10 e⁻³ mJ when the equivalence ratio rises from 0.57 to 1.0. For tetralin aerosols of 0.57 equivalence ratio, E_min increases from as 0.09 mJ to 0.32 mJ when the droplet diameter rises from 10 μm to 60 μm. The trends are in agreement with previous experimental observations. The method used in current work has the potential to prediction of the minimum ignition energy of aerosol.     

Research and application of risk and condition based maintenance task optimization technology in an oil transfer station

Oil transfer stations of PetroChina mostly scatter in Gobi, mountain areas or other sparsely populated areas, inconvenient transportation and absent professional engineers often delay the best time to repair the machines. Time-or interval-based maintenance (TBM) accounts for almost 100%, while, On-condition maintenance and other proactive maintenance are seldom adopted. TBM not only can't prevent happens of equipment fault but also cause the waste of the maintenance resource. In order to allocate maintenance resources reasonably, ascertain the minimum preventive maintenance requirement, ensure the reliability, availability and safety, this paper carries out a research on Risk and Condition Based Maintenance (RCBM) task optimization technology. Utilizing the internet of things (IOT), real-time database, signal-processing, Gray Neural Network, probability statistical analysis and service oriented architecture (SOA) technology, a Risk and Condition Based Indicator Decision-making System (RCBIDS) is built. RCBIDS integrates RCM, condition monitoring system (CMS), key performance management module, file management module, fault and defect management module, maintenance management module together, which aims to realize remote condition monitoring, maintenance technical support services (TSS), quantitative maintenance decision-making, and to ensure the Reliability, Availability, Maintainability and Safety (RAMS). The Predictive Maintenance Indicator model, reliability prediction model and Key Performance Indicator (KPI) model, which are embedded in the RCBIDS, are constructed separately. An engineering case shows that the risk and condition based maintenance task optimization technology can be used to optimize maintenance content and maintenance period, to minimize maintenance deficiencies and maintenance surplus, and to prolong the lifespan of equipment.     

浅析建立排污权有偿交易制度

随着工业化、城市化的快速推进,环境容量资源有限和社会经济持续较快发展的矛盾将长期存在。在充分运用必要的行政和法律手段的同时,应注重运用经济手段———排污权有偿使用和交易进行环境保护,使外部环境内部化,树立"容量有限、资源有价、使用有偿"的环境资源价值理念,推动企业自主创新和技术进步,降低企业内部治理成本,调动污染减排积极性,促进环境管理方式从粗放型向精细化转变,全面提升环境管理水平。     

无起爆药雷管内管装药密度对燃烧转爆轰的影响研究

起爆药雷管生产中产生大量有毒废水,且其运输、贮存存在安全隐患。为克服这些困难,笔者自行制备无起爆药雷管。采用圆筒式金属内管中装填超细PETN(季戊四醇四硝酸酯),作为起爆元件,代替起爆药部分,研究装药密度对内管燃烧转爆轰(DDT)的影响。研究结果表明,在内管壁厚1～2 mm,内径Φ4.0 mm,长25 mm,装压密度为0.8～1.14 g/cm3的范围内,内管能可靠实现燃烧转爆轰。     

Parallel and serial methods of calculating thermal insulation in European manikin standards

Standard No. EN 15831:2004 provides 2 methods of calculating insulation: parallel and serial. The parallel method is similar to the global one defined in Standard No. ISO 9920:2007. Standards No. EN 342:2004, EN 14058:2004 and EN 13537:2002 refer to the methods defined in Standard No. EN ISO 15831:2004 for testing cold protective clothing or equipment. However, it is necessary to consider several issues, e.g., referring to measuring human subjects, when using the serial method. With one zone, there is no serial-parallel issue as the results are the same, while more zones increase the difference in insulation value between the methods. If insulation is evenly distributed, differences between the serial and parallel method are relatively small and proportional. However, with more insulation layers overlapping in heavy cold protective ensembles, the serial method produces higher insulation values than the parallel one and human studies. Therefore, the parallel method is recommended for standard testing.     

国内特种作业培训考核管理工作机制现状研究

特种作业培训考核管理工作是安全生产的一项十分重要的基础工作,是国家为加强危险岗位管理而制定的一项强制性政策。2011年,北京市安监局将研究改进特种作业培训考核管理工作机制调研列为市局重点研究课题,调研工作分为现场调研、函件调研及电话咨询三种形式。本文在对北京市、其他直辖市,以及四川、江苏、辽宁、吉林、安徽、浙江和山西等九个主要省市特种作业培训考核管理工作机制调研基础上,阐述了目前我国主要省市特种作业培训考核管理工作机制现状,分析了国内主要的特种作业培训考核管理模式、特点、基本状况及主要优缺点。按照各部门之间的职能划分,全国各主要省市主要采取"一条龙"、"1+1"和"2+1"三种特种作业培训考核管理模式。     

民营中小企业安全文化建设探讨

企业安全文化建设对于企业安全管理起着至关重要的作用,民营中小企业作为我国经济体系的生力军,其安全管理工作必须注入新的安全管理理念、理论和方法。分析了民营中小企业安全文化建设的制约因素,在基于"本质安全、目标统一和全员参与"三个原则的基础上,初步构建由观念文化、制度文化、行为文化和物态文化四部分组成的民营中小企业安全文化建设框架,并提出相应的建设方法,对于民营中小企业的安全发展有着极其重要的意义。     

城市轨道交通火灾事故风险评估及对策措施

运用故障树安全评价的方法和火灾风险评估中的定量分析方法,以人员安全为出发点,对轨道交通运营过程火灾事故风险进行评估。并对重庆市轻轨2号线临江门车站进行紧急情况下人员疏散计算,判断轻轨临江门车站发生火灾等紧急事故时,能否确保乘客的人身安全。结合轨道交通现状给出相应对策措施,降低事故发生的可能性,确保乘客生命安全和财产不受损失。     

天然气应用对兰州大气环境的影响

煤烟型污染是兰州市大气污染严重的主要原因之一，西气东输工程对改变兰州市能源结构，改善城市环境质量具有非常重要的意义。根据兰州市大气污染现状和特性，以2000年为基准，分析研究了兰州市利用天然气前后能源结构，主要污染源及大气污染物排放量的变化。针对污染源状况和兰州市天然气用气规划，选用适宜模式预测了兰州市利用天然气后的各主要污染物的年平均浓度，计算了空气质量的改善程度。     

邻苯二甲酸酯类增塑剂的体外细胞毒性评价

邻苯二甲酸酯(Phthalate esters, PAEs)是环境介质中的一类典型的有机污染物。已有研究表明,PAEs具有明显的内分泌干扰毒性,并会对动物和人体的生殖发育与神经系统造成损伤。体外细胞评价模型因具有高通量、测试周期短、成本低和毒性效应易于探明等技术优点,被广泛应用到PAEs毒理学效应的研究中。本文从内分泌干扰毒性、胚胎发育毒性、神经毒性、免疫毒性、遗传毒性以及致癌作用等方面,对PAEs的一些体外细胞毒性评价模型进行了分类和总结,并对其相应的研究进展进行了综述。本文旨在为体外细胞毒性评价模型的有效利用提供借鉴,并对PAEs毒性作用机制的深入研究提供思路和依据。