Selection of appropriate organic additives for enhancing Zn and Cd phytoextraction by hyperaccumulators

Chelant-enhanced phytoextraction is one of the most promising technologies to remove heavy metals from soil. The key of the technology is to choose suitable additives in combination with a suitable plant. In the present study, laboratory batch experiment of metal solubilization, cress seeds germination were undertaken to investigate the metal-mobilizing capability and the phytotoxicity of organic additives, including ethylene diamine triacetic acid （EDTA）, citric acid, acetic acid, oxalic acid, glutamine and monosodium glutamate waste liquid （MGWL） from food industry. Experiments in pots were carried out to study the effects of the additives on Zn and Cd phytoextraction. Furthermore, a leaching experiment with lysimeter was performed to evaluate the environmental risks of additive-induced leaching to underground water. The results showed that EDTA had a strong mobilizing ability for Zn and Cd, followed by mixed reagent （MR） and MGWL. MGWL and acetic acid at 5 mmol equivalent per liter resulted in seed germination index less than 2%. Experiments in pots verified the phytotoxicity of acetic acid and MGWL. Addition of the mixed reagent at 6--10 mmol/kg significantly increased Zn phytoextraction by Thlaspi caerulescens. The same for EDTA and the mixed reagent at 10 mmol/kg by Sedum dfredii. But only mixed reagents could significantly increase Cd phytoextraction by the studied hyperaccumulators. This suggested that the strong chelant was not always the good agent to enhance phytoextraction. S. alfredii combined with 2--10 mmol/kg soil MR was preferred for phytoremediation of Cd/Zn contaminated soils in southern China, this could result in high phytoextraction of Cd/Zn and reduce the leaching risk to underground water than EDTA assisted phytoextration.     

Application of dynamic risk analysis in offshore drilling processes

Process safety is the common global language used to communicate the strategies of hazard identification, risk assessment and safety management. Process safety is identified as an integral part of process development and focuses on preventing and mitigating major process accidents such as fires, explosions, and toxic releases in process industries. Accident probability estimation is the most vital step to all quantitative risk assessment methods. Drilling process for oil is a hazardous operation and hence safety is one of the major concerns and is often measured in terms of risk. Dynamic risk assessment method is meant to reassess risk in terms of updating initial failure probabilities of events and safety barriers, as new information are made available during a specific operation. In this study, a Bayesian network model is developed to represent a well kick scenario. The concept of dynamic environment is incorporated by feeding the real-time failure probability values (observed at different time intervals) of safety barriers to the Bayesian network in order to obtain the corresponding time-dependent variations in kick consequences. This study reveals the importance of real-time monitoring of safety barrier performances and quantitatively shows the effect of deterioration of barrier performance on kick consequence probabilities. The Macondo blowout incident is used to demonstrate how early warnings in barrier probability variations could have been observed and adequately managed to prevent escalation to severe consequences.     

安全风险分级防控在油气开发领域的探索与应用

为推动油气开发领域安全风险分级防控有效落地,提高风险预控能力,本文基于风险防控现状评估结果,探索性地研究安全风险分级防控思路,构建了油气开发领域安全风险分级防控体系推进模型,提出了逆向与正向危害因素识别方法,明确了风险评价关键隐性过程原则,构建了风险-后果-能资分级防控决断模型。选取典型试点单位进行实践,结果证明,油气开发领域安全风险分级防控体系推进模型是科学合理的,其他领域也可借鉴该模型开展安全风险分级防控工作。     

锂电池检测的安全标准及安全防护研究

为评估并提高锂电池在使用、储存和运输过程中的安全,本文归纳总结了国内外锂电池安全检测的相关标准,对标准中测试项目异同作了重点分析和对比,并讨论了锂电池的安全风险及风险分级情况。同时,鉴于锂电池检测过程中可能出现的起火、爆炸等危险,探讨了电池检测过程的安全防护技术,并从样品区和试验区两方面提出了安全防护要求和建议。     

新型冠状病毒肺炎疫情期间企业生产安全风险管理

本文在分析新型冠状病毒肺炎疫情期间企业安全风险特点的基础上,建立了疫情期间安全风险管理模型,分析了这一特殊时期企业外部变化,以及企业内部人、物、环境、管理变化带来特殊安全风险,提出了针对性的风险管控措施。     

基于AHP-联系熵的应急预案实施过程风险评估

应急预案制定后的实施对于事故发生后预案的顺利运行至关重要,因此,有必要对应急预案实施过程的风险水平进行度量。以应急预案实施过程作为研究对象,基于风险理论与AHP-联系熵耦合方法开展风险评估。以应急预案实施过程风险水平为目标层,应急预案的宣传教育和培训、应急资源的定期检查落实、应急演习训练、应急预案的实用性检验、应急预案电子化、事故回顾等过程要素作为策略层,实施方法科学高效、调动工作者积极的态度、领导的重视和能力、设备的完整性作为方案层,形成应急预案实施过程风险评估三级模型;运用联系熵表征风险标准与应急预案实施过程风险水平这2个集对之间的关联性,在AHP结构模型和权重分配的基础上计算加权熵并得到目标层的总联系熵,对比标准熵区间得到应急预案实施过程的整体风险等级。结果表明,采用AHP-联系熵度量方法提高了评价结果的结构性和准确性,比传统直接加权的方法更符合实际情况。     

“T”型地铁换乘站多点火灾工况下综合火灾危险性研究

为探究大型地铁站多线路火灾场景中的综合危险性,采用火灾动力学软件FDS构建“T”型换乘站全尺寸模型,对不同火源位置、不同火源功率以及是否开启地铁排烟风机等12组工况进行数值模拟;采用性能化方法确定可用疏散时间,并通过综合火灾风险评估方法计算各工况总安全指数。结果表明:1号线站厅层和2号线站台层双点火灾为最不利火灾场景;1号线站台层和2号线站厅层双点火灾为相对安全火灾场景;火源功率的增大会增加地铁火灾危险性,但不同火源位置工况中的安全指数变化趋势相似;排烟模式开启前,1号线站厅层火灾会导致较大的火灾危险性;排烟模式开启后,地铁总安全指数显著上升且安全指数变化趋势改变,此时2号线站台层火灾会导致较大的火灾危险性。     

灾害救援中基于民众心理感知的应急物资多阶段分配问题研究

为有效解决在保证高效完成救援任务的同时考虑受灾民众行为,进而提高灾民对救援处置效果的满意度问题,结合行为运筹学相关理论和不公平厌恶理论,提出民众对于应急物资到达时间的风险感知度量模型,以及民众对于所得到的应急物资数量的公平满意度度量模型,构建基于灾民心理感知的应急物资多阶段调度模型,解决应急物资到达时间风险感知、物资分发数量公平满意度等多目标下的调配决策问题;设计基于蚁群优化思想的求解算法。研究结果表明:通过实例分析对比验证了模型在提升灾区民众对于应急物资分发策略满意度方面的有效性。     

基于模糊推理的FRAM事故定量分析方法研究

为有效克服FRAM事故分析中无法进行定量分析的缺陷,提出结合模糊推理技术的Fuzzy FRAM模型。此改进模型基于FRAM识别系统运行状态;依据功能输出要素的时间/精度属性利用Matlab构建2阶模糊推理系统量化功能输出质量;根据通用性能条件(CPC)及功能输入耦合端口构建功能评价体系,针对评价体系中存在的不确定性信息融合及建模问题,采用模糊证据推理技术,通过模糊信度结构建立、数据处理、信息融合测度后获得功能的风险指数;以既有铁路危险品运输事故为例,验证方法的可行性。结果表明:Fuzzy FRAM模型的评估结果较为精确,是FRAM分析方法的有效补充。     

数据挖掘在预测组织事故防控效果中的应用*

为进一步探索数据挖据技术在组织事故预防工作中的融入性与适用性,基于24Model构建事故预控基础模型,通过预测准确率数值及接受者操作特性曲线（ROC曲线）对比分析随机森林（RF）、支持向量机(SVM)、决策树（DT）与神经网络（NN）4种方法对组织事故防控效果的预测性能。结果表明:针对事故率控制（Y1）、职业危害预防（Y2）、财产损失3类预测目标（Y3）,RF方法均能达到较高的准确率及稳定性,具有较优的预测性能。根据特征重要度（FI）排序,明确对组织事故水平影响最显著的因素为安全实践活动认知（SC5）及安全管理程序文件（SMS3）,FI值均大于0.150 0。研究结果可为有效预测组织事故防控效果提供方法依据,同时为企业安全工作的规划设计提供思路。