Carbonaceous particles in the atmosphere and precipitation of the Nam Co region, central Tibet

A continuous air and precipitation sampling for carbonaceous particles was conducted in a field observatory beside Nam Co, Central Tibetan Plateau during July of 2006 through January of 2007. Organic carbon (OC) was the dominant composition of the carbonaceous particles both in the atmosphere (1660 ng/m³) and precipitation (476 ng/g) in this area, while the average elemental carbon (BC) concentrations in the atmosphere and precipitation were only 82 ng/m³ and 8 ng/g, respectively. Very high OC/BC ratio suggested local secondary organic carbon could be a dominant contribution to OC over the Nam Co region, while BC could be mainly originated from Southern Asia, as indicated by trajectory analysis and aerosol optical depth. Comparison between the BC concentrations measured in Lhasa, those at “Nepal Climate Observatory at Pyramid (NCO-P)” site on the southern slope of the Himalayas, and Nam Co suggested BC in the Nam Co region reflected a background with weak anthropogenic disturbances and the emissions from Lhasa might have little impact on the atmospheric environment here, while the pollutants from the Indo-Gangetic Basin of Southern Asia could be transported to the Nam Co region by both the summer monsoon and the westerly.     

企业安全管理存在的问题及对策

1企业安全管理存在的主要问题 虽然很多企业已认识到了安全的重要性,也认识到了安全工作重在预防,但仍然有一些企业只追求眼前利益,不愿进行安全投入。有些企业的安全管理,长期徘徊于传统的事后管理阶段,平时主要任务是搞检查,发生事故时搞追查,安全工作随着事故的变化而变化^[1]。跟在事故后面,头痛医头,脚痛医脚。     

采油厂化验室危险因素及对策

针对采油厂化验室的特点,对其存在的危险有害因素,从火灾爆炸、中毒、腐蚀、触电、机械伤害、人员、储存场所等方面进行了较为系统的分析,并提出了相应的对策措施。     

基于Anylogic的某高铁客运站人群疏散设施优化研究

高铁客运站突发事件下人员疏散具有不确定性、复杂性等特点,为研究疏散设施如何优化才能满足人员疏散要求,本文基于某高铁站客流路线图绘制高铁站人流疏散模型,利用Anylogic仿真软件进行疏散时间与疏散人数、楼梯宽度、闸机数量关系的模拟研究,并且对疏散出口区域的人流密度和人流量进行统计分析.结果表明:随着楼梯宽度的增加,总疏散时间会逐渐减小,但当楼梯宽度增加到一定程度时,总疏散时间反而会增大然后趋于稳定;随着闸机台数的增加,总疏散时间刚开始减小,后逐渐趋于稳定;分散设置疏散出口,适当控制闸机与闸机之间的距离,可避免闸机出口处人流密度过高.最后根据模拟结果,给出不同状态下人员疏散设施优化的合理建议,疏散设施的优化在一定程度上可以避免出现人员拥挤踩踏的群死群伤事故.     

氯气泄漏扩散过程及后果评价的研究现状分析

综述了氯气泄漏扩散过程及后果评价的研究成果。从现场试验、实验室模拟和数学模拟三方面分析了氯气泄漏扩散各研究方法的优势和局限性。强调了氯气泄漏扩散后果评价的必要性。指出:必须针对中国特有的一些重气扩散建立专属知识产权的数学模型;不同层次数学模型的精度皆有待于进一步提高;需加强基于特定数学模型的全过程统一界面模拟程序的开发。     

Study of nitrogen oxide absorption in the calcium sulfite slurry

Experiments were conducted using a bubbling reactor to investigate nitrogen oxide absorption in the calcium sulfite slurry. The effects of CaSO₃ concentration, NO₂/NO mole ratio and O₂ concentrations on NO₂ and SO₂ absorption efficiencies were investigated. Five types of additives, including MgSO₄, Na₂SO₄, FeSO₄, MgSO₄/Na₂SO₄ and FeSO₄/Na₂SO₄, had been evaluated for enhancing NO₂ absorption in CaSO₃ slurry. Results showed that CaSO₃ concentration had significant impact on NO₂ and SO₂ absorption efficiencies, and the highest absorption efficiencies of SO₂ and NO₂ could reach about 99.5 and 75.0 %, respectively. Furthermore, the NO₂ absorption was closely related to the NO₂/NO mole ratio, and the existence of NO₂ in flue gas may promote NO absorption. The presence of O₂ in simulated flue gas was disadvantage for NO _x removal because it can oxidize sulfite to sulfate. It was worth pointing out that FeSO₄/Na₂SO₄ was the best additive among those investigated additives, as the NO₂ removal efficiency was significantly increased from 74.8 to 95.0 %. IC and in situ FTIR results suggest that the main products were NO₃ ^? and NO₂ ^? in liquid phase and N₂O, N₂O₅ and HNO₃ in gas phase during the CaSO₃ absorption process.     

Aqueous leaching of cattle manure incineration ash to produce a phosphate enriched fertilizer

Ash produced from the combustion of livestock manure contains large amounts of phosphorus (P), which is an important resource as a fertilizer. Some studies have extracted and recovered P from incinerated biomass ash using inorganic acid or alkaline agents, which produce wastewater that requires treatment and is expensive due to the cost of chemicals. Livestock manure ash contains not only P, but also water soluble salts, which could be a negative influence on plant growth and shall be preferably removed from the recovered fertilizer. In this study, we removed salinity from cattle manure incineration ash by simple aqueous leaching, while retaining the P content. The optimal condition was a 20 min leaching time at a liquid/solid (L/S) ratio of 10 mL g-ash^?1. Under this condition, over 90 % of Cl and 20 % of Na in the original ash was removed, while over 99 % of the P was retained in the leached residue. The leached residue met the fertilizer standard in Japan in terms of citrate soluble fertilizer components and contained few heavy metals. X-ray analyses of the ash indicated that Cl was mainly present as KCl in the original ash, while P was mainly present as Ca compounds in the ash.     

Evaluation on the applicability of dry processed bottom ash as lightweight aggregate for construction fields

Currently, wet bottom ash is not sufficiently utilized due to its content of unburned coal, chloride and moisture. In contrast, bottom ash discharged from the recently introduced dry process spends a longer time on the clinker conveyer in the lower part of the boiler and consequently contains a significantly smaller amount of unburned coal. Consequently, it has high potential for use as a lightweight aggregate for construction material because of properties such as high porosity, low unburned coal content, non-chloride, and non-moisture. However, it is not frequently used for construction because the ash particle has a flat and thin shape, coarse surface and unfavorable structural strength. Against this backdrop, this study has conducted a range of experiments to identify the shapes, structure, density, absorption, percentage of floating particles, unit volume weight, solid volume, characteristics of air bubbles and micro pores, crushing strength of bottom ash, and the following results were observed. Though the dry bottom ash has sharp and angular edges, its flat and thin shapes lead to vulnerable structures. Dry bottom ash of the size of 0.6 mm or larger has 50–60 % of the total pore rate and 30–50 % of the closed pore rate. Considering these qualities, by removing the relatively fragile surface parts and making the particles more globular, dry bottom ash can be used as a lightweight aggregate for construction field having outstanding performance in terms of light weight and insulation.     

块茎类作物对农村垃圾中铅镉等重金属的吸附研究

随着城市的快速发展,工业化越来越深入人心,很多交通、化工类的重金属污染产业也迅速发展起来,这些造成了农村垃圾中重金属的种类和含量都在不断攀升.由于大气、水源的传播以及通过农作物进入人体,污染的范围不断扩大,造成的危害也越来越严重.文章利用布点采样分析的方法,调查了污染不同区域的农村垃圾重金属污染状况,对数据进行统计分析,为政府部门正确判断与决策提供科学的依据.     

SAFUIT/UF6环境评价模型验证与应用

作为核燃料循环过程中一种兼具辐射危害和化学毒性的中间产物,UF6的泄漏事故,特别是事故的环境评价技术越来越受到人们的重视.SAFUIT/UF6是专门针对此类事故的环境评价模型,目前已经开展了初步的验证工作.根据1987年法国UF6释放实验条件,对SAFUIT/UF6模型计算结果进行了误差分析,并与HG-SYSTEM/UF6模型进行了对比.初步认为SAFUIT/UF6模型可准确地模拟UF6扩散.此外,SAFUIT/UF6模型在某设施核事故应急评价系统中也得到了应用.