贮油罐区防火水幕模拟实验研究

本文通过对贮油罐区防火水幕冷态和模拟实验数据的分析比较,讨论了设计防火隔热水幕的形式方式,水幕喷头的结构选型等重要参数。     

Sensitivity of protective barrier performance to changes in rainfall rate

Single- or multi-layered surface barriers are used for protecting the underlying hazardous or radioactive waste storage facility and for reducing the risk of dispersion of contaminants to the ground water. To assess the effect of variations in net rainfall rate (total rainfall minus evapotranspiration) on the hydraulic response of a multi-layered barrier, a series of flow simulations were performed. Water fluxes in different layers of the barrier were numerically calculated for three net rainfall rates, i.e. 0.0255, 0.0742, and 0.141 cm/day. These rates correspond to dry, average, and wet climatological conditions in Belgium. Results show that for dry conditions, almost 45% of the water infiltrating the top of the barrier is laterally evacuated. When the net rainfall rate increases from 0.0255 to 0.0742 cm/day, more water is being laterally diverted, and only 22% of the applied rainfall percolates through the barrier. If the rainfall rate is increased from 0.0255 to 0.141 cm/day, the percolation becomes 14% of the applied rainfall. This indicates that fluxes leaving the bottom of the repository increase only slightly, although the rainfall rate for wet conditions is approximately 5 times larger than for dry conditions. Under dry conditions a slightly negative pressure develops in the bottom of the low-permeability clay layer. However, this desaturation does not affect the integrity of the clay.     

城市绿化的生态化

本文从城市绿化的生态化战略着眼,研究提出城市绿化发展的生态化格局,结合深圳城市绿地系统规划实践,总结了相关技术措施。     

雷静电作用下储气库安全危害分析

为保障能源储备安全,探究雷电和静电对储气库安全的影响。根据雷电和静电理论,构建储气库雷静电概率模型,分析雷静电对储气库的影响。考虑天然气扩散的特殊性,选取高斯烟羽模型预测气体扩散范围,并结合闪火后果准则对闪火危害范围进行分析,构建CCPS-BST模型对爆炸危害范围预测,分析风速及大气稳定度对三种危害后果的影响。结果表明,雷静电会增加储气库泄漏后发生闪火和爆炸的概率,气体扩散范围和闪火后果沿主导风向呈梭形分布,蒸气云爆炸后果由中心向四周扩散,三种危害范围都与风速和大气稳定度呈相反的变化。研究结果可为多因素下储气库安全分析研究提供参考,为降低灾害后果和维护储气库的日常安全提供了理论依据。     

食物垃圾开放式乳酸发酵的实验研究

利用食物垃圾发酵生产乳酸,是实现其资源化的有效途径之一.底物不灭菌的开放式发酵,是一种简单、有效的利用食物垃圾生产乳酸的方式.通过对发酵过程中ρ(乳酸),ρ(总糖),ρ(可溶性糖)以及细菌数量变化的研究,对开放式发酵的机理进行了分析.结果表明:食物垃圾适于作为乳酸发酵的底物,在不投加任何营养物质的条件下,能促进乳酸菌的大量增殖.采用开放式发酵,可从食物垃圾产生36.29 g/L的乳酸,远高于封闭式发酵(底物灭菌).垃圾中土著菌群在开放式发酵中起到了分解复杂多糖和为乳酸菌提供可发酵性底物的作用,从而提高ρ(乳酸).      

煤矸石堆放场周围玉米作物中苯并(a)芘污染特征

以焦作矿区演马矿煤矸石堆放场周围农田玉米为研究对象,对玉米中苯并(a)芘污染特征进行了分析研究.在矸石堆周围布设三条采样线采集玉米样品,玉米样品经提取、浓缩、净化处理后采用高效液相色谱(HPLc)法对其中苯并(a)芘含量进行检测分析.结果表明,研究区玉米作物叶子中苯并(a)芘污染水平较高,达46.7%,茎和籽均未出现苯并(a)芘污染现象,且玉米各部位苯并(a)芘含量与距矸石堆距离呈反比.进一步指出矿区企业应加强对周围环境生态的预防保护,以确保企业的可持续发展.     

铁屑微电解法处理蓄电池生产中含铅酸废水

介绍铁屑微电解法处理蓄电池含铅废酸水的新工艺,经运行实践表明,该工艺对处理含铅废酸水,具有工艺简单可靠,处理稳定效率高,针对性强,经济效益明显,排放水水质达国家废水排放标准。     

Network calculations and ascendency based on eco-exergy

Ascendency is an index of activity and organization in living systems calculated in terms of flows. The concern here is with how that quantity behaves when the flows in question are measured in terms of eco-exergy. The storage of eco-exergy has served as a goal function in assessing parameter values for structurally dynamic models, but network magnitudes and topologies can change in response to significant changes in the forcing functions. As storages are relatively insensitive to such changes, it is advisable in such cases to explore how changes in a flow variable, like ascendency, might capture network adaptations. It happens that changes in ascendency calculated in terms of flows of simple energy are small in comparison to corresponding variations in the storages of eco-exergy. But when ascendency is reckoned in terms of flows of eco-exergy, its changes in response to network changes are more comparable to those in the storages. Ascendency seems to be more sensitive to changes in flow topology, however, so that a combination of eco-exergy storage and eco-exergy ascendency would probably be most appropriate for situations where changes in flow topology are significant.     

碳捕获与油藏封存CO_2气源途径经济性比较方法

气源是影响碳捕获与封存技术推广的关键因素之一。以CO2气藏、含CO2天然气藏和高能耗企业废气三种气源途径为对象,研究了气源途径的经济性比较方法,构建了P1、P2指标及其计算模型,并对模型中经济要素在不同气源途径下的构成和计算方法进行分析。最后采用上述方法对中国现运行的三个捕集示范项目进行了实例验证。该研究的方法可以为CO2-EOR项目气源途径选择决策提供指导。     

琼江河流域森林生态系统水源涵养能力估算

森林生态系统的水源涵养功能是其生态功能的重要组成部分.琼江流域森林生态系统是长江上游生态屏障的重要组成部分,其森林生态系统的水源涵养功能将极大地影响当地的生产生活.文章以四川省遂宁地区琼江河流域2007年森林资源二类调查数据为基础,运用综合蓄水能力法,比较了研究区不同森林类型、林龄、海拔、坡度下的林冠降雨截留能力,枯落物最大持水量和土壤蓄水能力,评估了区域尺度森林生态系统的水源涵养能力.结果表明,2007年,研究区内森林生态系统涵养水源总量为1125.02×104 m3.其中,林冠层截留占总涵养水源量的18.07%,枯枝落叶层持水量占3.34%,土壤蓄水量达到78.59%,是森林涵养水源的主体.柏木因其面积上的优势,使得其水源涵养贡献率最大,达到92.44%;阔叶混交林单位面积涵养水源量最大,达到1568.39 t·hm-2,其次是针阔混交林(1517.10 t·hm-2),经济林(1461.99 t·hm-2),针叶混交林的水源涵养能力最弱,仅1045.39 t·hm-2,主要是因为研究区内针叶混交林土壤的非毛管孔隙度较小.因绝大多数有林地的海拔都处在300~500 m处,使得其水源涵养贡献率最大,达到98.65%.同时,平坡森林生态系统的水源涵养能力最强,达到1171.92 t·hm-2,其次是缓坡,可达1150.59 t·hm-2,能力最小的是陡坡森林生态系统,仅1147.34 t·hm-2.近50 a来,研究区内森林覆盖率变化较大,按照其“十二五”规划,研究区在2015年森林覆盖率将达到45%,根据其森林面积的变化估计其森林涵养水源量可达1511.2×104 m3.在对研究区水源涵养功能及其差异认识的基础上,进行合理经营与管理,可以最大限度地发挥森林生态系统服务功能.