日本的水井、水车、贮水槽

1995年1月17日,日本大阪与神户之间的兵库县南部地区发生了7．2级强烈地震,后被称作阪神大震灾。地震会导致房倒屋塌,与此同时,还会引起次生灾害,例如大面积的火灾。关东大震灾,死亡14万人,其中被火烧死的5．6万人,约占35％。这次阪神大震灾,同时有数百处发生火灾,仅神户市就有390处。据日本警察厅统计,阪神大震灾共毁掉建筑物10．94万多幢,死亡5291人,其中有30％是被火烧死的。     

孤立波作用下不同长宽比圆端形桥墩受力数值分析∗

为研究极端波浪灾害对近海铁路桥墩的水动力作用,基于CFD数值软件进行入口边界造波,结合k?ω湍流模型求解RANS方程,采用孤立波模拟极端波浪,建立数值水槽,并利用理论公式验证了数值水槽的可靠性。为探究桥墩长宽比对圆端形桥墩受力的影响,在数值水槽中开展了孤立波作用下不同长宽比（L/D）圆端形桥墩的三维数值模拟,研究了圆端形桥墩长宽比对桥墩周围波浪爬高、流速及桥墩波浪力的影响。研究结果表明：不同长宽比圆端形桥墩最大波压均发生在静水液面位置;桥墩长宽比对波浪爬高、墩周流场影响明显;圆端形桥墩受到的最大波浪力、墩底最大弯矩随着长宽比的增加而增加,当长宽比较小时,二者呈线性关系。     

攀钢120t转炉屋顶电除尘器集水槽的设计与改进

集水槽是屋顶电除尘器的主要组成部件之一,也是屋顶电除尘器与常规电除尘器结构设计的重要区别之一。文中叙述了在屋顶电除尘器设计过程中对此部件设计所要考虑的问题及设计方法,并对其需改进之处提出了展望。     

重复一遍

化学实验室,一位实验员向一个大玻璃水槽里注水.水流很急,水槽里的水不一会就灌得差不多了.那位实验员去关水龙头,万万没想到水龙头坏了,怎么拧也关不住.水很急,再有半分钟,就会溢出水槽,流到两旁的工作台上.一旦水浸湿工作台上的仪器,仪器便会爆裂,里面正在反应的药品流出,遇到空气会猛烈燃烧,几秒钟之内就能把实验室变成一片火海.     

液化条件下沉积物中氮、磷的释放规律

湖泊、海岸沉积物中的氮(N)、磷(P)等营养物质可以通过静态扩散或沉积物再悬浮向水体中释放。沉积物再悬浮过程中N、P的释放量可能大于静态扩散的释放量,特别是沉积物液化时再悬浮过程会对水体中N、P浓度产生重要影响。本文利用波浪水槽试验,研究了沉积层中的N、P在静置固结阶段(I)、加波未液化阶段(Ⅱ)、加波液化阶段(Ⅲ)中的释放规律。试验结果表明:阶段I水中的总磷(TP)、溶解性总磷(TDP)、总氮(TN)、溶解性总氮(TDN)浓度最低。阶段Ⅱ水中TP比阶段I提高了数倍,阶段Ⅱ水中TDP浓度比阶段I平均仅提高了0.2倍;阶段Ⅲ水中TP和TDP比阶段I分别提高可达59倍和25倍。阶段Ⅱ和Ⅲ水中TN、TDN均比阶段I提高了数倍。     

Nitrogen sink in a small forested watershed of subtropical China

Global nitrogen (N) emission and deposition have been increased rapidly due to massive mobilization of N which may have longreaching impacts on ecosystems. Many agricultural and forest ecosystems have been identified as secondary N sources. In the present study, the input-output budget of inorganic N in a small forested watershed of subtropical China was investigated. Inorganic N wet deposition and discharge by stream water were monitored from March, 2007 to February, 2009. The concentrations and fluxes of inorganic N in wet precipitation and stream water and net retention of N were calculated. Global N input by dry deposition and biological fixation and N output by denitrification for forested watersheds elsewhere were reported as references to evaluate whether the studied forested watershed is a source or a sink for N. The results show that the inorganic N output by the stream water is mainly caused by NO3??-N even though the input is dominated by NH4 +-N. The mean flux of inorganic N input by wet precipitation and output by stream water is 1.672 and 0.537 g N/(m2 yr), respectively, which indicates that most of inorganic N input is retained in the forested watershed. Net retention of inorganic N reaches 1.135 g N/(m2 yr) considering wet precipitation as the main input and stream water as the main output. If N input by dry deposition and biological fixation and output by denitrification are taken into account, this subtropical forested watershed currently acts as a considerable sink for N, with a net sink ranging from 1.309 to 1.913 g N/(m2 yr) which may enhance carbon sequestration of the terrestrial ecosystem.     

低碳消费与低碳意识

看了上期相关低碳经济的主题,想起身边发生的小事。朋友家厨房自来水龙头漏水,漏得不多,一滴落出来,另一滴紧接着从龙头里流出来。建议朋友应该尽快把水龙头修好,节水环保。朋友说：“这样滴水,水表不走,不用花钱,还可以拿水盆接水。”我试验了一下,晚上放一盆在那,早上早早地就满了,有很多水已经溢出流走了,而且朋友也并不是总能想起来把水盆放在水槽中。     

风浪扰动下的太湖悬浮物实验与模拟

采用太湖湖区底泥,根据波浪水槽实验总结了各种扰动强度下太湖底泥的起动切应力.波浪水槽可以系统地模拟太湖常见的波浪强度.通过实验确定了太湖底泥的临界切应力为0.050 Pa,采用国外先进的FVCOM模型计算模拟了太湖流场和悬浮物分布并和太湖实测资料进行了对比,结果较为合理,证明了模型的有效性.由于目前太湖的野外监测资料存在较明显的时空不一致性.模型参数率定的精度受到了较大影响,太湖悬浮物与太湖底泥的内源释放以及水体的透明度有较大关系,因此通过室内实验研究太湖的悬浮物规律对太湖的富营养化治理具有重要意义.