The Influence of Anchor Devices on the Performance of Retractable Type Fall Arresters Protecting Against Falls From a Height

Retractable type fall arresters are part of the equipment used for protecting people against falls from a height. They are an intermediate part between full body harness worn by a man and the structural anchor at the worksite. The most important task of retractable type fall arresters is to arrest people’s falls and to reduce their harmful consequences. Information received from users as well as laboratories testing protective equipment indicates that the performance of such equipment is incorrect under specific conditions. The paper is concerned with an analysis of the conditions in which retractable type fall arresters demonstrate intermittent performance and with an explanation of that phenomenon. The results of tests investigating anchor devices and the performance of retractable type fall arresters are presented. External and internal factors contributing to intermittent performance have been determined and guidelines for safer use of these devices have been developed.     

An optimal level of dust explosion risk management: Framework and application

The current research provides guidance on the prevention and mitigation of dust explosion using a Quantitative Risk Management Framework (QRMF). Using concepts drawn from previous studies, the framework consists of three main steps: (i) a new combined safety management protocol, (ii) the use of DESC (Dust Explosion Simulation Code) and FTA (Fault Tree Analysis) to assess explosion consequences and likelihood, respectively, and (iii) application of the hierarchy of controls (inherent, engineered and procedural safety). QRMF assessment of an industrial case study showed that the original process was at high risk. DESC simulations and Probit equations determined the destructive percentages. FTAs revealed high probabilities of explosion occurrence; in addition, detailed individual and societal risks calculations were made, before and after the framework was applied. Based on the hierarchy of controls technique, the framework showed significant risk reduction to the point where the residual risk was acceptable for the process.     

内蒙古农业灌区夏、秋浇的氮磷流失变化

通过对内蒙古农业灌区引黄灌溉的2次主要大规模灌溉（夏浇、秋浇）的跟踪监测,研究了农业灌区的氮磷流失情况.分析了2次灌溉期的各引水渠和排水渠中总氮（TN）、氨氮（NH4＋-N）、硝氮（NO3--N）、总磷（TP）、溶解性无机磷（DIP）、溶解性有机磷（DOP）、颗粒磷（PP）的变化情况.研究表明：夏浇时,由于植物吸收、灌水量小等因素,基本不产生污染.而秋浇期间,由于灌水量大、土地裸露成为非点源污染产生的主要时期.在对第8排域的TN、TP的连续监测中发现,排干沟中的总氮总磷含量基本维持在4.16mg.L^-1和0.1725mg.L^-1,且氮为主要的污染控制因子;排干沟中的N/P为24,排入乌梁素海中极易引起水华发生.结合河套农业灌区的自然条件、耕作方式等因素,综合分析了河套灌区在夏浇及秋浇时期的非点源污染产生过程及污染特点.为该地区非点源污染管理和控制提供科学依据.     

Sudden high concentration of TSP affected by atmospheric boundary layer in Seoul metropolitan area during duststorm period

Hourly concentrations of TSP, PM(10), PM(2.5) near the surface at Seoul city were examined from March 20 to March 25, 2001 (duststorm event) in order to investigate the effect of a duststorm generated in China on the local aerosol concentration in Korea, The ratios of fine to coarse particles such as TSP to PM(10), TSP to PM(2.5) and PM(10)-PM(2.5) to PM(2.5) showed that a great amount of dust transported from the origin of the duststorm was remarkable with a maximum ratio of 9.77 between TSP and PM(2.5). Back trajectories every 6 h showed the movement of dust particles in the lower atmosphere near 500 m to 1500 m (atmospheric boundary layer), which implied transport from Baotou in inner Mongolia of northern China to the direction of Seoul city in Korea and then the back trajectories passed near the southern border of Mongolia and Baotou through Zengzhou in the midlevels (3000 m) and low levels (500 m) of China, finally reaching Seoul city. So, the TSP concentration at Seoul city was partially influenced by the duststorm, under the prevailing westerly wind and the transported aerosols could influence high concentrations of pollutants of TSP, PM(10) and PM(2.5) in Seoul. The sudden high concentrations of TSP and PM(10) were found for a few hours, especially at 1500 to 1800 LST, March 22. At 1200 LST, before the passage of a cold front through the Korean peninsula, the convective boundary layer (CBL) near Seoul was not shallow, but at 1500 LST, under the frontal passage, the CBL was remarkably thinner (less than 300 m), due to the compression of the boundary layer by the intrusion of cold air. This resulted in the increase of the TSP concentration, even though the mixed layer above maintained almost the same depth. At 1800 LST shortly after the frontal passage, that is, near sunset, the nocturnal cooling of the ground caused air parcels to cool, thereby enhancing the shallower nocturnal surface inversion layer and producing the maximum concentration of TSP of 1388 microg/m(3) near Seoul city.     

Falls and fall prevention programmes in developing countries: environmental scan for the adaptation of the Canadian Falls prevention curriculum for developing countries

Problem

Falls in older persons in developing countries are poorly understood, and falls prevention and health promotion programmes for this population are largely lacking.

Methods

A systematic review was carried out of relevant literature on falls and prevention programmes, and falls prevention education, and a scan undertaken of health promotion programmes for older persons in a representative country - South Africa.

Results

Studies on the risk and prevalence of falls are largely retrospective and hospital-based, with varied methodology, including study period, sampling method and sample size. Falls prevalence is based largely on self-reports in studies on general trauma in all age groups. Falls incidence varies from 10.1% to 54%. No reports could be traced on sustained falls prevention or health promotion programmes.

Conclusion

Scant research has been conducted and little preventive education offered on falls in older persons. Adaptation of the Canadian Falls Prevention Curriculum for developing countries will help to fill gaps in knowledge and practice.

Impact on industry

With rapid increase in the populations of older persons in developing countries, research on age related disorders such as falls is required to guide policy and management of falls.     

Characteristics of the vibrating-mesh minimum ignition energy testing apparatus for dust clouds

A novel apparatus for testing the minimum ignition energies of flammable dusts is introduced. Unlike the conventional apparatus (the Hartmann tube), this new apparatus employs a vibrating mesh to produce a dust cloud. Using three kinds of powders, namely lycopodium, anthraquinone and polyacrylonitrile, which are designated as the samples for calibration by the International Electrotechnical Commission (IEC, 1994) standards, fundamental characteristics were experimentally investigated. Concerning the minimum ignition energies (MIEs), the new testing apparatus worked well for two samples, lycopodium and polyacrylonitrile. The MIE for anthraquinone, however, was by far larger than the expected value. We concluded that the aggregation of anthraquinone particles is the main cause of the difference and is attributable to both the tribo-charges acquired by the particles when passing through the mesh and the filamentary shape of the crystal. Other essential factors for characterizing the testing apparatus, such as the concentration of dust, the shape and spacing of the sparking electrode system, and the impedance of the sparking circuit are discussed.     

综采工作面粉尘运移和粉尘浓度三维分布的数值模拟研究

分析了综采工作面流场及粉尘分布的特点 ,视工作面含尘风流为气 粒两相流 ,建立了描述综采工作面风流中粉尘运动和浓度分布的数学模型。采用计算流体力学的有限容积法求解 ,编制了模拟计算综采工作面三维空间内风速和粉尘浓度分布的计算机程序     

双极不对称预荷电静电增强过滤除尘技术的应用

双极不对称预荷电静电增强过滤除尘技术 ,是国家“九五”科技攻关课题所取得的成果之一 ,该技术采用双极不对称荷电增强方式 ,将普通静电增强效果与粉尘凝并机能有机地结合在一起 ,既提高了过滤除尘器的收尘效率 ,尤其是呼吸性粉尘的效率 ,同时又极大地改善了滤料粉尘层的结构 ,可显著地降低过滤阻力增值 ,节约运行能耗。笔者研究的该技术应用于焊接车间的焊接烟尘的治理上 ,取得了良好的效果。现场测试表明 ,该技术对焊接烟尘的滤除效率提高了 3% ,尤其对微细粉尘效果显著 ,2 μm粉尘穿透率相对下降了 4 7%。采用超细滑石粉高粉尘负荷测试结果表明 ,过滤阻力增值降低达 30 % ,清灰效果明显改善     

改良MPS型抑尘剂在料堆防尘中的试验研究

阐述了改良MPS型系列抑尘剂在料堆防尘中的试验研究.该类抑尘剂既防尘又具有抗水性能,防尘期长且成本低廉,适合各种露天料堆、料场.     

闪速炉烟尘收尘装置的改造

简要概述了闪速炉气力输送系统收尘装置的改造和圆筒型布袋收尘装置在气力输送系统中使用的效果.