排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
简要介绍了我国地漏的现状与问题,并结合SARS病毒在香港淘大花园传播的原因,说明了地漏安全问题的严重性。根据香港城市大学的实验,提出了利用洗脸盆排水保护地漏存水弯水封,从而解决地漏的安全问题。 相似文献
2.
从人防工程内消防系统的重要性入手,分别从消防水源、消火栓系统的独立分区、消防阀门的设置以及消防排水4个方面探讨了人防工程内消防设计的一些常见问题,强调设计中应考虑平、战结合,方便临战时转换。 相似文献
3.
4.
三峡库区消落区周期性干湿交替环境对土壤磷释放的影响 总被引:19,自引:8,他引:11
以三峡库区消落区典型江段万州断面为试验基地,以释磷能力较强的紫色土为对象,根据三峡水库消落带的"干湿交替"空间和时间特征,进行万州断面土壤磷释放的实验室模拟试验,分析了周期性"淹水-落干"干湿交替对土壤磷释放的影响.研究发现,在"淹水-落干"干湿交替条件下各形态磷在水土界面释放的活性为:Ca2-P,Fe-P>Cas-P,Al-P>O-P>Ca10-P;T-P在每次淹没时释放量递增,从第1次的15.4 mg·kg-1,到第3次26.5 mg·kg-1;磷在持续淹水状态下释放的主要动力为Ca2-P在水相的溶解和还原状态下Fe-P的释放,其中Ca2-P活性最高,由淹水初期的14 mg·kg-1降至5 mg·kg-1左右;而干湿交替条件下P的释放主要是氧化-还原条件变换下Fe-P的形态转换.淹水并不会使O-P释放,但可以使O-P活化,使其在落干氧化时转化为Fe-P,在下一次淹水时释放.研究发现每次淹水时土壤的有效磷水平都略有增加,每次落干时较上次落干时有效磷水平降低. 相似文献
5.
Hefu Pu Aamir Khan Mastoi Xunlong Chen Dingbao Song Jinwei Qiu Peng Yang 《Frontiers of Environmental Science & Engineering》2021,15(4):67
6.
7.
Louis H. Motz 《Journal of the American Water Resources Association》1990,26(2):233-239
ABSTRACT: A drain function and set of type curves were defined for the mathematical solution that represents one-dimensional flow under nonsteady conditions in a leaky aquifer for the constant drawdown boundary condition. A match point procedure was developed for determining the aquifer parameters transmissivity, storage coefficient, and leakance based on the drain function and type curves. Use of the procedure is illustrated by an example that utilizes simulated aquifer drawdowns and flowrate data. The drain function and type curves developed in this investigation include the effects of leakage for the constant drawdown boundary condition, which is not included in the existing drain function and type curve found in the literature. Thus, a new set of type curves was developed that can be used to analyze drawdowns for one-dimensional flow in a leaky aquifer with constant drawdown at a line sink. Applications would include flow to a canal or river, drainage of agricultural lands, and dewatering associated with strip mining operations. 相似文献
8.
9.
控制排水条件下土壤氮素的运移 总被引:2,自引:0,他引:2
为研究暗管控制排水与非控制排水条件下, 不同排水出口控制高度对土壤中氮素分布和迁移的影响, 在湖北省荆州市四湖工程管理局丫角排灌试验站进行了野外试验。试验结果表明, 无论采取控制排水与否, 土壤垂直剖面上硝态氮浓度均有一致的变化规律: 20 cm处浓度最高, 在40~60 cm浓度急剧减小, 60~80 cm浓度值很小(1 mg/kg左右); 控制排水对土壤硝态氮的减小率有显著影响, 表现在控制水位越高, 土层间硝态氮减小率最大; 控制排水能降低表层土壤硝态氮的迁移; 铵态氮与硝态氮迥然不同, 无论采取控制排水与否, 铵态氮在土壤垂直剖面上的含量变化不大; 控制排水对铵态氮的含量也有一定的影响, 表现在控制排水位越低, 土壤中铵态氮的含量越小. 相似文献
10.
A devastating crude oil vapor explosion accident, which killed 62 people and injured 136, occurred on November 22, 2013. It was one of the most disastrous vapor cloud explosion accidents that happened in Qingdao's storm drains in China. It was noted that blast overpressure and flying debris were the main causes of human deaths, personal injuries and structure damages. Two months after the accident, it was reported that there were three contentious issues in the investigation report. First issue was the discrepancy between the temperature of the crude oil vapor explosive limits which were measured by the investigation panel and the temperature reported by the local fire department. Second issue was the contradiction between the upper explosive limit and vapor pressure of the crude oil vapor. The last issue was the location of the ignition source which led to the explosion.In the present study some specific features of this accident and various causes led to the explosion, high casualties and severe damages were analyzed. Three contentious issues in the official investigation report were investigated and tested in detail. The first element tested was the explosive limits and limiting oxygen concentration of the crude oil vapor at different temperatures. Based on theoretical analysis and field investigations, the last two elements in the report were analyzed from multiple perspectives. Based on the TNO Multi-Energy model and PROBIT equations, damage probability of affected people at the leaking site was also estimated. The investigation concluded with a result that precautions need to be taken to prevent flammable gas explosions in the drainage systems. Key steps were explicitly discussed for improving the hazard identification and risk assessment of similar accidents in the future. 相似文献