基于20 L球罐的多相混合物扩散模拟

为更好地探索多相混合物的爆炸特性，以铝粉、乙醚、空气为研究对象，基于20 L球型爆炸罐建立三维计算模型，对气固两相和气液固三相混合物的分散过程进行数值模拟，以分析不同多相混合物分散过程的差异，并为测量多相混合物爆炸下限时的点火延迟时间设定提供参考。监测分析铝粉浓度粒子分布、流场内部湍流动能以及液相体积百分数等的演化过程，讨论混合物分散效果的差异，并确定测量爆炸下限的点火延迟时间。研究结果表明:实验工况下，液相的存在会降低粉尘云团的湍流动能、降低其扩散速度，并使粉尘云内部浓度更均匀。测量多相混合物爆炸下限时，三相混合物的最佳点火延迟时间早于气固两相混合物10~20 ms。     

基于超声透射特性的密闭容器液位测量与装置设计*

针对金属密闭容器内液体液位测量问题,设计1种基于超声透射特性的非接触式液位测量装置。测量装置根据被测容器内液体介质与气体介质透射系数不同的原理,通过超声接收探头回波情况判断容器内液体位置,利用软件与硬件结合,调整超声发射探头与接收探头的放大倍数,实现对不同材料、厚度容器内液位的测量。测量装置可以将所测液位、容器倾斜程度等数据通过上位机、阿里云平台等多方位显示。研究结果表明:该测量装置可测量不同材料、厚度密闭容器内承装液体的液位,所测数据较为稳定,测量误差范围不大于3 mm。     

Seaborne Petrochemical Spill Analysis Within the United States, 1992–1999

Through discussion of causative factors and examination of historical data, petrochemical spill prevention in US waters is reviewed. Unintentional petrochemical outflow is analyzed in a comprehensive manner and presented as a hierarchical sequence of antecedent events to reveal the trends of causative factors leading to release. Specifically, a seaborne petrochemical spill is examined in terms of four basic, antecedent events: (1) an underway source, (2) a failure incident, (3) a marine accident capable of breaching the hull and cargo block, and (4) the onset of outflow. These events are further subdivided into underlying, contributing events to form a causative framework for spill prevention. While a hierarchical review is not necessary to uncover the elements of causation, it does provide a comprehensive and logical structure that clearly defines these elements in terms of occurrence frequency and contribution to resulting outflow. It is found that relatively small, frequent spills less than 40,000 liters (10,567 gallons), attributable to human operator failures, leading to grounding, and cargo transfer system failure accidents, dominate US seaborne petrochemical outflow from 1992 to 1999. Given the frequency of groundings, structural reinforcement regulations such as those contained in the Oil Pollution Act of 1990 (requiring double hulls) appear well justified. However, passive restraint systems are secondary to the need for vigilant training and licensing of tank vessel operators.     

冷库压力容器声发射在线检测技术研究

冷库中在用制冷压力容器长期运行在安全状况不明的状态下,危及了设备的运行安全和安全生产,成为困扰我国特种设备定期检验工作的难题.通过分析总结氨制冷压力容器的结构特点和检测难点,依据声发射检测技术的原理和在线整体检测的技术特点,将其应用于在用制冷压力容器.解决无法开罐全面检验方面的难题.     

柱形压力容器开口泄爆过程数值模拟研究

为研究柱形压力容器泄爆规律,采用经典流体力学软件FLUENT对典型的柱形压力容器泄爆过程进行数值模拟,分析从泄爆口开启到泄压结束时间段压力发展、火焰传播、气体流动及可燃气体浓度变化特性。结果表明:不同泄爆压力下容器内压力发展变化呈现不同特点,在较小泄爆压力情况下会出现压力再度上升的双峰现象。泄爆过程中产生的湍流沿泄爆口附近容器壁拉长火焰面,并加快燃烧速率。同时就容器内不同点火位置对爆炸强度影响进行研究,得出在泄爆压力为0.04 MPa时,底面点火对本柱形压力容器产生的最大升压速率约为中心点火最大升压速率的1.4倍。     

Toxic effect of microcystin-LR on blood vessel development

Abstract

The effect of microcystin-LR (MC-LR) at 50–1000?nmol/L on blood vessel development of zebrafish embryos has been explored. Upon exposure 72-h-post-fertilization (hpf), the hatching rate was significantly reduced and malformation and fatality rates were increased in a dose-dependent manner. MC-LR induced cell cycle arrest in the G0/G1-phase and damaged DNA structure in a dose-dependent manner. In human umbilical vein endothelial cells (HUVECs), MC-LR led to decreased activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) and increased lipid peroxidation. These findings indicated that MC-LR could cause oxidative DNA damage, which mediated cell cycle arrest and inhibited cell proliferation afterwards, and retarded the blood vessel development.     

渤海湾客滚船危险货物安全运输现状分析与对策

针对近五年来渤海湾客货滚装船车载化工产品货物常见种类及危险性分布情况进行了全面的统计,阐述了渤海湾航线客货滚装船车载化学品运输现状,分析了渤海湾航线客货滚装船车载化学品运输存在的问题以及载有危险货物运输车辆客货滚装船在发生事故时可能带来的危害.提出了加强管理部门间协作、疏导与查堵相结合、制定适应渤海湾短途航运的货物危险性测试标准以及引导和促进货物生产商、经营者、运输单位提前进行货物危险性测试分类,并采用合适的包装方式及警示标志等加强载有危险货物运输车辆客滚船安全管理的重要措施.     

液化天然气加注船安全定量风险分析

液化天然气（LNG）加注船是一种为LNG动力船提供燃料的新型船舶,国内目前尚处于起步阶段,缺乏相关安全标准和规范。采用国际定量风险评价（QRA）的通用理念,研究适用于我国LNG加注船的安全评价方法,提出具体实施步骤和依据准则,并以国内某LNG加注船作为实例分析说明。建立加注船LNG火灾事故树,确定相关火灾事故概率;研究适合加注船火灾事故后果的方形火焰模型,以及LNG火灾热辐射对人体伤害的计算方法;参考国际海事组织（IMO）的风险准则,确定LNG加注船个人风险和社会风险;最后与按NFPA-59A计算的防火间距作对比分析。通过计算,例中加注船的风险位于须采取相关安全措施的ALARP区域,风险控制区域半径20m。若按NFPA-59A要求计算防火间距,该加注船对外部须划定半径52m区域作为安全区域,且须将船身增长37m以满足内部防火要求,在实际工程中无法实现,相比较QRA方法更适合我国LNG加注船的安全评价工作。     

关于NB/T47012-2010中TP2管村的许用应力

许用应力的选取是强度计算的前提,TP2高效管由于加工工艺特点造成其许用应力选取与其热处理状态有关,本文通过试验对轧丝后的高效管的拉伸试验和硬度进行测试,讨论翅片加工工艺对强度和硬度的影响,并讨论了同一根TP2管材不同热处理状态的许用应力如何选取,并提出对铜合金材料,笔者认为其许用应力采用强度极限除以安全系数更加合理。     

Threats of illegal,unregulated, and unreported fishing to biodiversity and food security in the Republic of the Congo

Illegal, unregulated, and unreported (IUU) fishing poses a major threat to effective management of marine resources, affecting biodiversity and communities dependent on these coastal resources. Spatiotemporal patterns of industrial fisheries in developing countries are often poorly understood, and global efforts to describe spatial patterns of fishing vessel activity are currently based on automatic identification system (AIS) data. However, AIS is often not a legal requirement on fishing vessels, likely resulting in underestimates of the scale and distribution of legal and illegal fishing activity, which could have significant ramifications for targeted enforcement efforts and the management of fisheries resources. To help address this knowledge gap, we analyzed 3 years of vessel monitoring system (VMS) data in partnership with the national fisheries department in the Republic of the Congo to describe the behavior of national and distant-water industrial fleets operating in these waters. We found that the spatial footprint of the industrial fisheries fleet encompassed over one-quarter of the Exclusive Economic Zone. On average, 73% of fishing activity took place on the continental shelf (waters shallower than 200 m). Our findings highlight that VMS is not acting as a deterrent or being effectively used as a proactive management tool. As much as 33% (13% on average) of fishing effort occurred in prohibited areas set aside to protect biodiversity, including artisanal fisheries resources, and the distant-water fleet responsible for as much as 84% of this illegal activity. Given the growth in industrial and distant-water fleets across the region, as well as low levels of management and enforcement, these findings highlight that there is an urgent need for the global community to help strengthen regional and national capacity to analyze national scale data sets if efforts to combat IUU fishing are to be effective.