Comparative study of the methodologies based on Standard UNE 60079/10/1 and computational fluid dynamics (CFD) to determine zonal reach of gas-generated Atex explosive atmospheres

This study presents two methodologies which can be used to determine the classification and extended area of hazardous zones caused by gas, vapours and mists. The first is based on UNE 60079/10/1: Electrical apparatus for explosive gas atmospheres – Part 10: Classification of hazardous areas, whilst the second is developed on the basis of Computational Fluid Dynamics (CFD) using the FLUENT software application. Both methodologies were applied in the same case study of differing leakage components from a dairy farm steam boiler room fuelled by liquid natural gas (LNG).The results obtained show that CFD methodology is a powerful tool with a significant capacity for determining the size of an explosive atmosphere for a broad range of exhaust sources. This methodology offers more conservative results than those obtained from the analytical methodology recommended in Standard UNE 60079/10/1. Results obtained using CFD are more useful in enabling the study of turbulence phenomena, boundaries, and diverse initial and contour conditions.In contrast, the Standard UNE 60079/10/1 methodology is less conservative and aims at determining the hypothetical volume V_z of the explosive atmosphere. This volume is a measurement of the ventilation efficiency which is in turn proportional to a massive gas release through an exhaust source divided by the number of air changes in the enclosed area.From the results obtained, it can be confirmed that Standard UNE 60079/10/1 should be revised.     

轻柴油储罐火灾过程及安全性评价

从 2 0 0 2年 1月 1日起我国实施新的“轻柴油”产品标准 ,新标准将轻柴油的闪点指标由原来的≥ 65℃改为≥ 5 5℃ ,由此导致轻柴油的火灾危险类别发生变化 ,并进而引发原有轻柴油储罐能否安全储存新标准轻柴油的问题。笔者利用化学流体力学模型和挪威船级社 (DNV)的SAFETI风险评估软件对 65℃闪点和 5 5℃闪点轻柴油的储存火灾危害性进行了评估 ,取得了轻柴油火灾中危害程度的计算机模拟结果     

运用系统决策方法优选大气污染治理方案

本文运用层次分析和多目标决策技术来量化大气污染治理方案的综合效益,从而为最佳治理方案的选取提供了科学依据.     

物元分析在环境工程方案评标中的应用

根据物元分析理论，建立了环境工程方案评标的数学模型，并成功地应用于某废水治理工程的中标方案的优选工作中。     

居室生活新主张

居室是休闲的场所，环保是时尚的话题，现代休闲生活没有环保的品质，那简直是不可想象。这方面，讲究生活品质的人士很有心得，居室生活是他们倡导生活品质的第一站。让我们一起来分享他们的环保居室新生活主张。[编者按]     

Re-Os同位素体系在地球科学中的应用

在汇总本世纪六十年代以来国际上Re Os同位素地质学主要文献的基础上 ,概括总结了Re Os同位素地质学几十年来的研究成果。系统地介绍了Re Os同位素体系在地质年代学和示踪研究方面的应用。阐明了Re Os地质年代学的定年原理、实验技术、优势 ,以及应注意的问题 ;归纳总结了Re Os在陨石、大陆壳和地幔等不同储库中的丰度、分布及演化特征 ;回顾了近年来Re Os同位素体系在陆壳演化、洋岛玄武岩和地幔羽成因及陨石撞击等示踪研究方面的工作和进展。     

Freeliving marine nematodes as a pollution indicator of the Bohai Sea

A hierarchical diversity index-taxonomic distinctness index Δ , which was first defined by Warwick and Clark in 1998, was　employed to evaluate the pollution status of the Bohal Sea with freeliving marine nematodes. The result showed that the Bohal Bay and other　coastal sampling sites might be affected by oil and gas production and other anthropogenic influences. In other words, anthropogenic disturbance　was affecting this component of the benthos in these locations. And most offshore sampling sites in the middle of the Bohai Sea were clear and　unpolluted.     

燃烧法在草浆碱回收中的优化应用

碱法制浆黑液污染治理的根本出路是碱回收。燃烧是碱回收的主要技术手段。本文从碱回收理论与应用实践结合出发，对燃烧法草浆碱回收的工艺，设备及运行条件进行了具体分析，并提出了有针对性的改进措施，以供参考。     

上海市环境保护局办公自动化系统的升级改造方案

上海市环境保护局计划对原有内部办公自动化系统进行升级改造。文章针对市环保局的现状及实际需求，提出了继续以Lotus Domino／Notes为系统平台和应用数据库的开发工具。并以关系型数据库为归档数据库，选用Java，Java Script、XML作为开发工具，开发前台应用系统的B／S结构模式的设计改造方案。介绍了设计原则，结构模型，并以收文管理流程为例，进一步介绍了模块的应用。     

低速下不同类型机动车暴露声级和最大声级的测定

本文叙述了对低速下不同类型机动车暴露声级 (LAE)和最大声级 (LmaxF)的测试 ,给出了测试结果 ,并对结果进行了讨论