Numerical Simulations on the Effect of Sea–Land Breezes on Atmospheric Haze over the Pearl River Delta Region

The atmospheric haze over the Pearl River Delta (PRD) was investigated by using the Models-3 Community Multi-scale Air Quality modeling system with meteorological fields simulated by the Fifth-generation National Center for Atmospheric Research/Penn State University Mesoscale Model (MM5) from September 26th to September 30th, 2004. The model-simulated meteorological elements and particulate matter with aerodynamic diameter less than 10 μm (PM₁₀) were compared with observations at four air quality-monitoring stations. The results showed that MM5 successfully reproduced the diurnal variations of temperature, wind speed, and wind directions at these stations. The temporal variations of the simulated values were consistent with those of the observed (such as temperature, wind speed, and wind direction). The correlation coefficient was 0.91 for temperature and 0.56 for wind speed. The modeling results show that the spatial distributions of simulated PM₁₀ were closely related to the source emissions indicating three maxima of PM₁₀ over the PRD. The sea–land breezes diurnal cycle played a significant role in the redistribution and transport of PM₁₀. Nighttime land breeze could transport PM₁₀ to the coast and the sea, while daytime sea breeze (SB) could carry the accumulated PM₁₀ offshore back to the inland cities. PM₁₀ could also be transported vertically to a height of up to about 1000 m because of strong turbulence in the SB front. Process analyses indicated that the emission sources and the vertical diffusion were the major processes to influence the concentrations of particulate matter with aerodynamic diameter less than 2.5 μm (PM_2.5).     

我国道路交通事故成因分析及预防对策

提出机动车驾驶员安全裕度的概念,对道路交通事故进行成因分析,在此基础上建立了事故成因层次结构模型,运用层次分析法确定道路交通事故成因权重,打破了以往只考虑数量的单一因素的分析方法,综合考虑了人、车、路、环境对交通事故的影响作用,比较客观地得出了道路交通事故主要成因,并提出预防对策.     

Process industry accidents in Sri Lanka: Analysis and basic lessons learnt

Accidents in the process industry could be prevented or reduced by having good safety management measures. Such preventive measures could be further improved through the experiences and lessons learnt from past accidents. Therefore, analysis results of past accidents are valuable sources of information for determining root causes and as case material to prevent and reduce the adverse consequences of accidents in the process industry.This paper looks at accidents in the process industry that have occurred in the past 10 years from 1997 to 2006 in Sri Lanka to gain an understanding of the nature and consequences of accidents. Lessons and main areas of concern to improve safety in the Sri Lanka process industry are discussed. The analysis is done for different event types based on specific operating process stage during which the accident occurred such as processing, loading and unloading, repair and maintenance and storage, the immediate effect types such as fire, explosion, chemical releases and emissions and the consequences of each accident. Fire incidents were observed in 38 accidents analyzed. The results show that the highest number of accidents has occurred during processing operations followed by accidents during maintenance and repair work. The cause analysis shows that many accidents have occurred due to technical and human failures.The accidents are then classified according to the severity of the consequences in order to compare the nature of accidents experienced in Sri Lanka with respect to accidents in other countries in the world.     

A fuzzy analytic network process for multi-criteria evaluation of contaminated site remedial countermeasures

The Analytic Network Process (ANP) has been proposed to incorporate interdependence and feedback effect in the prioritization of remedial countermeasures using a hierarchical network decision model, but this approach seems to be incapable of capturing the vagueness and fuzziness during value judgment elicitation. The aim of this paper is to present an evaluation method using a fuzzy ANP (FANP) approach to address this shortcoming. Triangular fuzzy numbers (TFN) and their degree of fuzziness are used in the semantic scale as human judgment expressed in natural language is most often vague and fuzzy. The method employs the alpha-cuts, interval arithmetic and optimism index to transform the fuzzy comparative judgment matrix into set of crisp matrices, and then calculates the desired priorities using the eigenvector method. A numerical example, which was drawn from a real-life case study of an uncontrolled landfill in Japan, is presented to demonstrate the process. Results from the sensitivity analysis describe how the fuzziness in judgment could affect the solution robustness of the prioritization method. The proposed FANP approach therefore could effectively deal with the uncertain judgment inherent in the decision making process and derive the meaningful priorities explicitly from a complex decision structure in the evaluation of contaminated site remedial countermeasures.     

Exploring oil and gas industry workers’ knowledge and information needs

Many incident reports and much research literature have concluded that incident rates in high-hazard industries can be reduced by enhancing the knowledge and information sources available to workers. However, a sparsity of published research reporting workers' perspectives on the value of information and knowledge sources in different operational situations potentially limits the effectiveness of interventions aimed at improving human responses to process safety performance. In response, this work seeks to understand how frontline oil and gas industry workers, responsible for managing process safety and other risks in their hazardous workplaces, rely on their own knowledge, the knowledge of others and information provided to manage different operating scenarios. A set of open and closed-ended survey questions were distributed to workers at several upstream and downstream oil and gas companies. Statistical analysis of 133 responses revealed interesting insights relating to participants’ experience levels, decision making practices and perceptions on the importance of various information and knowledge sources in different operating circumstances. The data revealed differences in the sources of knowledge relied upon by experienced and less experienced workers. Experienced workers rely on their own knowledge in both routine and potentially high-impact scenarios. Less experienced workers also rely on their own knowledge for routine decisions however they reported seeking out external knowledge and information in potentially high-impact scenarios. The data suggests that interventions to improve safety by enhancing the availability of knowledge and information sources are less likely to affect experienced workers and alternate strategies might be needed. However, such interventions might be effective if they are focused on supporting newer workers.     

Competency requirements for process hazard analysis (PHA) teams

Process hazard analysis (PHA) is a cornerstone of process safety management programs. The quality of the PHA performed directly affects the level of risk tolerated for a process. The lower the quality of a PHA, the more likely higher risk will be tolerated. There are few requirements for PHA team members in the U.S. Occupational Safety and Health Administration's process safety management regulations. More detailed requirements for participation in a PHA are desirable.A competency management program should be used to ensure PHA practitioners and teams are appropriately qualified. Criteria for selecting PHA team leaders, or facilitators, and other team members are key to such a program and are described in this paper. The criteria cover both technical and personal attributes. Application of the criteria is described and team performance metrics, which can be used to correlate performance with the assessment of competency to validate the criteria and methods used, are discussed.Owing to the importance of the role played by team leaders, certification of their competency is desirable. Criteria for certification are described and their application is discussed.     

Integration of Recursive Operability Analysis,FMECA and FTA for the Quantitative Risk Assessment in biogas plants: Role of procedural errors and components failures

With more than 350 GWh per year and thousands of installations around the world, biogas is an appealing strategy in the field of energy production and industrial waste optimization. In this sense, it is of paramount importance to address the risk associated with such plants, as an increasing trend of accidents have been recorded in the last 20 years. In this work, a representative biogas production plant was considered, and a risk assessment was carried out through the combination of Recursive Operability Analysis and Failure Mode and Effects Criticality Analysis. The methodology is rigorous and allows for both the identification and the quantification of accidental scenarios due to procedural errors and equipment failures, which miss in the literature for the case of biogas. The analysis allows the automatic generation of the Fault Trees for the identified Top Events, which can be numerically solved. Results show that the most critical accidental scenario in the biogas plant here considered is the formation of an explosive air-biogas mixture, which can occur in both anaerobic digester and condensate trap. The calculated probabilities agree with the results available in literature on similar plants. Pumps and Distributed Control System were found to be the most critical components.     

安全仪表系统的开发与要求

综述安全仪表系统的发展过程;对其主要组成、特点以及其各自要求进行研讨;给出安全仪表系统开发的简化流程;探讨安全仪表系统的经济性分析和仪表选择方法;对安全仪表系统整体生命周期中的计划编制、设计、实施、运行、维护和确认等各阶段活动的关键要求进行了讨论和研究。该研究对安全仪表系统的深入理解有指导作用,并为安全仪表系统的分析、设计、实施、运行和维护等活动提供参考。     

基于生命周期评价理论的旅游产业发展研究——以张家界为例

旅游业是国民经济的战略性产业。基于生命周期理论,分析了旅游地生命周期的发展对旅游业发展的影响。以张家界市为例,分析了影响旅游地生命周期发展阶段的因素及张家界旅游生命周期阶段,提出了通过推动旅游地旅游产品推陈出新,加强景区利益协调和推动低碳环保的张家界旅游发展路径。     

Evaluating sustainable forest management strategies with the Analytic Network Process in a Pressure-State-Response framework

Nowadays forestry faces a complex management situation; the understanding of sustainable forest management (SFM) has gone far beyond the original meaning of sustainable yield of timber. SFM strategies should fulfil ecological, economic and social functions without causing damage to other ecosystems. In this understanding, forest management actions cannot be seen as isolated or mono-causal. In this case study, indicators for SFM are arranged in a Pressure-State-Response (PSR) framework at forest management unit level. This framework links pressures on the environment caused by human activities with changes of environmental state (condition) parameters. Forest management also responds to these changes by instituting environmental and economic measures to reduce pressures and restore natural resources. The Analytic Network Process (ANP) is utilized to evaluate the performance of four management strategies with regard to the PSR framework on SFM. Priorities of indicators and alternatives are modelled with the ANP resulting from the interconnections to other indicators and their respective cumulative importance. The approach allows for more detailed information on the network of human influences and their impacts on forest ecosystems and goes beyond the limitations of flat-dimensioned indicator sets.