雷击火形成及预防扑救对策

雷击火作为天然火源是一种难以控制的自然现象,其形成机理极为复杂。雷击火与雷暴的活动密切相关。     

影响飞机燃油箱惰化系统参数的数值研究

选取单个飞机燃油箱,运用CFD方法模拟了燃油箱惰化系统的惰化过程。CFD方法的模拟结果与文献中的理想混合模型及经验公式吻合较好。通过模拟,发现增加富氮气体的流量、提高富氮气体中的氮气含量可以缩短惰化时间,而增加富氮气体喷嘴直径和燃油箱的体积则会延长惰化时间。其他参数如燃油箱的形状和富氮气体喷嘴位置对惰化时间没有明显的影...     

有限单元算法在水质模拟中的应用研究

利用模拟河流水质的二维水质模型和有限单元算法,使用MATLAB软件进行计算程序的编写,开展该模型和有限单元算法在三峡库区水质模拟的适用性研究。有限单元法的基本思路是把一个连续的环境空间离散为若干个单元,每一个单元都可以是作为一个完全混合的子系统,通过对每一个单元建立质量平衡方程,从而建立起体系模型。模拟因子包括:BOD5、COD、NH3-N三项。由计算值与监测值进行比较后可知,与监测值误差最大的为NH3-N,可达23.8%;最小的为BOD5,误差为5.3%。由此可以说明,本课题的用于三峡水库水质预测的二维水质模型具有较高的精度,能够用来模拟预测三峡水库蓄水以后的水质变化状况。     

多孔填充材料的防火防爆机理及应用

在液化气体、燃料储罐内填充多孔材料,可有效地减少或避免储罐发生爆炸事故.本文分析了这类材料的防爆机理并简要介绍了其应用情况.     

微电池滤床法处理含油废水

介绍了含油废水中油珠电荷的来源和ζ－电位,阐述了液膜池微观电泳测试的理论和方法。根据油珠具有ζ－电位及在外电场作用下可以迁移的性质,采用炭－铁粒料组成微电池滤床处理含油废水,油去除率可达７０％－８０％。     

藻细胞特性对净水工艺的影响研究

以藻细胞的基本特征为基础,概括了目前净水工艺除藻的一般方法和原理,分析阐明了藻细胞特征对净水工艺的影响机制。      

废橡胶制备燃料油和炭黑

介绍了由废旧橡胶通过催化裂解制备燃料油和炭黑的方法,着重探讨了影响燃料油产率的因素,结果表明在优化条件下燃料油收率达42％,炭黑纯度在97％以上。     

DEHP、DBP内分泌干扰活性的实验研究

利用MCF-7细胞增殖实验、细胞周期分析、细胞雌激素受体水平测定和断乳大鼠子宫增重实验探讨了邻苯二甲酸二乙基己酯(DEHP)和邻苯二甲酸二丁酯(DBP)内分泌干扰活性及其可能的作用机制.结果表明,DEHP和DBP可诱导MCF-7细胞增殖、细胞内雌激素受体水平增高,对细胞周期无明显影响,DEHP不引起断乳大鼠子宫增重.推断DEHP和DBP可能并不是通过模拟雌激素而是引起体内天然激素受体水平改变等其他机制影响机体内分泌系统.     

Landfill Bioreactor Cells as Ecofilters for Extraction of Bio-energy and Nutrients from Solid Wastes

This paper describes a modified, ecologically based waste treatment technique, where municipal solid waste is anaerobically treated in landfill reactorcells in a way that both bio-energy and nutrients can be recovered. The controlled landfill reactorcell ('bioreactor-cell') serves as an anaerobic filter, where energy is extracted as biogas while nutrients are recovered through the leachates. The leachates can be used as fertilizer in e.g. energy forests within the controlled landfill area, and thus nutrients can be brought back into an ecocycle. At the same time anaerobic conditions result in an effective immobilization of heavy metals and other pollutants, e.g. through complexation to organic matter or as insoluble metal sulphides, which are immobilized in the fermentation residue. The long-lived organic fraction, remaining after the fermentation process has declined, containing a high content of lignine, serves as a water-holding matrix. Thus it helps to enforce a sustainable high moisture level, resulting in sustainable anaerobic conditions with heavy metals retained on a long-term basis. Also non-degradable products, like plastics, help to shield off oxygen and maintain reliable anaerobic conditions. Landfilling of organic matter under anaerobic conditions is a measure to counteract increasing concentrations of CO₂ in the atmosphere, resulting from human activities. A small fraction of the organic matter is long-term accumulated in the landfill, and the processes can be compared to those of natural wetlands.     

EFFECTIVE USE OF LANDSAT DATA IN HYDROLOGIC MODELS1

ABSTRACT: In a cooperative demonstration project, NASA and the U.S. Army Corps of Engineers (Corps) compared conventional and Landsat-derived land-use data for use in hydrologic models, and the resulting discharge frequency curves were analyzed. When a grid-based data-management system was used on a cell-by-cell basis (size about 1.1 acres or 0.45 hectare), Landsat classification accuracy was only 64 percent, but, when the grid cells were aggregated into watersheds, the classification accuracy increased to about 95 percent. When both conventional and Landsat land-use data were input to the HEC-1 model for generating discharge frequency curves, the differences in calculated discharge were judged insignificant for subbasins as small as 1.0mi² (2.59 km²). For basins larger than 10mi² (25.9km²), use of the Landsat approach is more cost-effective than use of conventional methods. Digital Landsat data can also be used effectively by local and regional agencies for hydrologic analysis by incorporating the data into grid-based data-management systems. The transfer of this new technology is well under way through inclusion in some Corps training courses and through use by both county government personnel and private consultants.