基于WebGIS和粒子系统的空气污染预测动态可视化展示技术

在完成国家"863"项目"重点城市群大气复合污染综合防治技术与集成示范"(3c-star)的过程中,我们研发了具有自主知识产权的"区域大气环境综合管理和辅助决策系统",其中创造性地利用NetCDF、Silverlight、WebGIS、粒子系统、多媒体等技术实现了空气污染预测动态可视化数据展示。本文阐述了工作的背景、技术要点及成果。     

脱硫石膏粒径分布与脱水性能实验研究

脱硫石膏粒径分布是影响脱硫石膏浆液脱水性能的重要因素之一,以干法、湿法筛分和研磨破碎获得不同粒径分布的脱硫石膏,在相同的过滤条件下,对不同粒径分布脱硫石膏浆液脱水性能进行了研究,实验结果表明,当脱硫石膏粒径d50大于50μm且（d90-d10）小于100μm,真空过滤最大真空度不低于0．098MPa,过滤时间不少于2．5min,滤饼厚度不超过20mm时,石膏滤饼含水率可以降低到12％以下（最低可达10％）;d50在17μm为脱硫石膏在相同的过滤条件下能够实现真空脱水干燥的转折点;d50和（d90-d10）共同影响石膏脱水性能,d50小于20μm时,仅表现为d50的影响。     

Matrix based fertilizers reduce nitrogen and phosphorus leaching in three soils

We compared the efficacy of matrix based fertilizers (MBFs) formulated to reduce NO3-, NH4+, and total phosphorus (TP) leaching, with Osmocoate 14-14-14, a conventional commercial slow release fertilizer (SRF) and an unamended control in three different soil textures in a greenhouse column study. The MBFs covered a range of inorganic N and P in compounds that are relatively loosely bound (MBF 1) to more moderately bound (MBF 2) and more tightly bound compounds (MBF 3) mixed with Al(SO4)3H2O and/or Fe2(SO4)3 and with high ionic exchange compounds starch, chitosan and lignin. When N and P are released, the chemicals containing these nutrients in the MBF bind N and P to a Al(SO4)3H2O and/or Fe2(SO4)3 starch-chitosan-lignin matrix. One milligram (8000 spores) of Glomus intradices was added to all formulations to enhance nutrient uptake. In all three soil textures the SRF leachate contained a higher amount of NH4+, NO3- and TP than leachate from all other fertilizers. In all three soils there were no consistent differences in the amount of NH4+, NO3- and TP in the MBF leachates compared to the control leachate. Plants growing in soils receiving SRF had greater shoot, root and total biomass than all MBFs regardless of Al(SO4)3H2O or Fe2(SO4)3 additions. Arbuscular mycorrhizal infection in plant roots did not consistently differ among plants growing in soil receiving SRF, MBFs and control treatments. Although the MBFs resulted in less plant growth in this experiment they may be applied to soils growing plants in areas that are at high risk for nutrient leaching to surface waters.     

Influence of Na2S on the degradation kinetics of CCl4 in the presence of very pure iron

This paper presents the results of kinetic studies to investigate the effect of FeS film formation on the degradation rate of CCl(4) by 99.99% pure metallic iron. The film was formed by submersing metallic iron grains in an oxygen free HCO(3)(-)/CO(3)(2-) electrolyte solution. When the grains had reached a quasi steady-state value of the corrosion potential, Na(2)S((aq)) was injected. Upon injection, a microm thick poorly crystalline FeS film formed immediately on the iron surface. Over time, the iron became strongly corroded and both the FeS film and the metallic iron grains began to crack leading to exposure of bare metallic iron to the solution. The effect of the surface film on the degradation rate of CCl(4) was investigated following four periods of aging, 1, 10, 30, and 60 days. Relative to the controls, the 1-day sulfide-aged iron showed a substantial decrease in rate of degradation of CCl(4.) However, over time, the rate of degradation increased and surpassed the degradation rate obtained in the controls. It has been proposed that CCl(4) is reduced to HCCl(3) by metallic iron by electron transfer. The FeS film is substantially less conducting than the bulk iron metal or non-stoichiometric magnetite and from the results of this study, greatly decreases the rate of CCl(4) degradation relative to iron that has not been exposed to Na(2)S. However, continued aging of the FeS film results in breakdown and stress-induced cracking of the film, followed by dissolution and cracking of the iron itself. The cracking of the bulk iron is believed to be a consequence of hydrogen embrittlement, which is promoted by sulfide. The increase in CCl(4) degradation rate, as the FeS films age, suggests that the process of hydrogen cracking increases the surface area available for charge transfer.     

A comparison of the low frequency electrical signatures of iron oxide versus calcite precipitation in granular zero valent iron columns

Geophysical methods have been proposed as technologies for non-invasively monitoring geochemical alteration in permeable reactive barriers (PRBs). We conducted column experiments to investigate the effect of mineralogy on the electrical signatures resulting from iron corrosion and mineral precipitation in Fe0 columns using (a) Na2SO4, and (b) NaHCO3 plus CaCl2 mixture, solutions. At the influent interface where the reactions were most severe, a contrasting time-lapse electrical response was observed between the two columns. Solid phase analysis confirmed the formation of corrosion halos and increased mineralogical complexity in the corroded sections of the columns compared to the minimal/non-corroded sections. We attribute the contrasting time-lapse signatures to the differences in the electrical properties of the mineral phases formed within the two columns. While newly precipitated/transformed polarizable and semi-conductive iron oxides (mostly magnetite and green rust) increase the polarization and conductivity of the sulfate column, the decrease of both parameters in the bicarbonate column is attributed to the precipitation of non-polarizable and non-conductive calcite. Our results show that precipitate mineralogy is an important factor influencing the electrical properties of the corroded iron cores and must be considered if electrical geophysical methods are to be developed to monitor PRB barrier corrosion processes in situ.     

人群疏散行为仿真技术研究

提出并建立了一种人群疏散仿真模型。针对疏散空间中障碍物的动态布局,采用网格法获得各障碍物包围盒坐标,依据最短路径原则采用几何法确定每个个体起始疏散路径,解决了人群疏散的空间连续性问题。针对人群疏散时个体之间的差异性,依据个体与个体之间的作用力、摩擦力动态改变个体的行进方向,以及依据人群密度采用人群疏散速度模型实时确定每个个体的运动速度,解决了个体之间的动态避碰、绕行和超越等问题。针对人群疏散时多个出口的选择问题,提出了把出口拥挤状态与个体心理慌乱状态相结合的出口选择方法。最后采用粒子系统实现了上述人群疏散行为的二维仿真并取得了较好的效果。     

内抽外压式集尘器实验、数值模拟与分析

根据内抽外压式集烟尘器专利研制了一个内抽外压式集尘器,并在井下进行实验。经过3种方法测试均收到预期的的效果,司机工作区达到了国家卫生要求,由于采用外筒压风,防止了瓦斯积聚避免瓦斯爆炸。应用离散颗粒模型模拟了内抽外压式集尘器内气相流场和粉尘颗粒的运动,该集尘器不仅把矿井巷道中细微可呼吸粉尘吸收到除尘器中,又能防止了瓦斯积聚。数值模拟与实验结果的一致性表明:把内抽外压式集尘器放置在掘进机前方,由于粉尘在气流的携带下运动使掘进机司机在矿井巷道中的工作环境得到改善,减少矿工患尘肺病的概率,开发了井下集尘的新工艺、新设备。     

安全评价方法在危险废物处置环境风险评价中的应用探讨

对安全评价方法在危险废物处置建设项目环境风险评价中的运用进行初步探索。主要用"工艺过程风险因素分析表"对工艺过程潜在风险性识别;用蒙德法进行源项分析;用池火灾模型、蒸气云爆炸伤害模型对易燃、易爆物质的火灾、爆炸等重大事故后果进行计算,得出人员的伤亡半径和财产损失半径等参数,以便于判断风险的可接受水平。分析结果表明:采用安全评价方法对危险废物处置建设项目进行环境风险评价是适用的、可行的。     

广东坡地红壤颗粒组成状况的研究──Ⅱ.土壤颗粒组成的空间分异

讨论了广东坡地红壤类土壤颗粒组成的空间分异现象,阐述了岩性、地形条件、水文动力学对颗粒组成空间分布的影响,指出地形条件、水动力学作用对广东坡地红壤类土壤颗粒组成的影响,在很大程度上是由广东所处区域的生物气候条件决定的。     

强化混凝去除微污染原水胶体颗粒的研究

对珠江水系统进行了强化混凝处理,燕利用准弹性激光散射技术（PCS）对常规混凝和强化混凝前后水中胶体颗粒（小于0.45um)的大小与分布进行了测定,探讨了搅拌条件对混凝效果的影响。