浅析河流允许排污量计算的设计流量

对淮河淮南段水污染物允许排放量计算中出现大流量小允许排放量的反常现象进行了讨论,并从河流纳污能力形成机制和排污量计算方程等方面问题的产生原因作了定量剖析,又以淮南市段为实例,对设计流量应如保判别和确定作了初步探讨。     

海水入侵污水放流系统及其清除研究

研究海水入侵污水放流系统及其清除特性有助于系统优化设计和运行保护。运用水力学一般原理推导了清除流量和入侵临界流量的估算公式,并根据数学模型模拟结果讨论了部分系统参数对清除和入侵的影响,指出系统沿程阻力的增加及扩散器主管截面逐渐减小对减小清除流量作用不大,而立管在主管底部与主管联结与在顶部联结相比一般可减小清除流量10％以上。系统清除流量和人侵临界流量与立管个数成正比。还介绍了鸭嘴阀,文丘里喉管等几种限制入侵和帮助清除的技术措施。介绍的方法与结果可供工程实际应用。     

基于概率物理模型的贮存可靠性评估方法

针对小样本高截尾试验信息贮存可靠性评估问题,提出了基于概率物理模型的贮存可靠性评估方法.通过对概率物理模型与传统指数模型的贮存可靠性评估方法进行对比分析,分别利用2种评估方法进行模型参数拟合、无失效数据可靠性评估和系统可靠性评估,发现无论是从拟合精度,还是小样本数据评估方面,概率物理模型评估方法都更符合工程实际.该模型...     

生活垃圾卫生填埋场渗滤液处理系统工程设计

本文从工程的角度出发对垃圾填埋场渗滤液处理系统工程设计中的几个重点、难点计算参数,以及目前国内外几个典型垃圾填埋场的渗滤液处理工艺流程、处理效果做了介绍,并在此基础上提出了几点建议     

氟硅酸循环条件下氟吸收系统的设计及应用

在要求H2 SiF6 浓度 16 %～ 2 0 %的氟硅酸循环生产普钙的系统中 ,采用吸收室和湍球塔结合的方法 ,保证了尾气达标排放     

现行的UASB反应器的设计问题及改良的可行性

探讨了UASB反应器的设计问题和改良的可行性。重点介绍并评价了UASB反应器的器内流速关系以及对应的问题。对比第 3代厌氧反应器的特点 ,提出了UASB反应器可行的改良方法。作为改良可行性证据 ,提供了改良后的实验数据     

小型城市污水厂设计中的问题及探讨

分析了小型城市污水厂的特点和存在的问题。处理工艺的优化选择是解决问题的关键。必须根据当地的水质、水量特点、受纳水体的水质标准、经济状况选择工艺类型     

The ‘Bayesics’ of Ranked Set Sampling

Ranked set sampling can be useful when measurements are expensive but units from the popu- lation can be easily ranked. In this situation one may draw k units from the population, rank them, select one on which to make the expensive measurement, draw another k units, rank them, select one, and so on. The method was originally suggested by McIntyre (1952) in connection with pasture yields and is obviously applicable in other situations as well. Dell and Clutter (1972) and Patil et al. (1994) explain the basics from a classical point of view. Our aim is to examine the procedure from a Bayesian point of view, determine whether ranked set sampling provides advantages over simple random sampling and explore some optimality questions     

Urban Stream Rehabilitation: A Design and Construction Case Study

/ This paper describes the fundamental design features, and construction methods and sequence, of a rehabilitation project on a small suburban creek in Moscow, Idaho, USA. A meandering channel pattern was reestablished for approximately 280 m of straightened, dredged channel, a new floodplain was excavated, and the new riparian zone was replanted. The new stream channel was sized to accommodate an estimated natural bankfull discharge ( approximately 5.6 cms), and floodplain design attempted to match the conveyance of the old enlarged channel (14-20 cms). The project was coordinated by a local nonprofit environmental organization, and the design and construction were tailored to donated materials and a largely volunteer labor force. A high-magnitude flood event (ca. 50-year recurrence interval) six months after construction had no significant impact on the newly constructed channel and revetments, but underscored the need for important detailing of the structures. The use of volunteer labor, while entailing certain benefits, complicates project planning and construction. The most general lesson learned from this project is that sponsoring agencies and clients need to be informed of the many steps and sequencing of properly constructed, complex stream rehabilitation projects as well as the high time and cost requirements for these tasks. KEY WORDS: Stream corridor restoration; Channel design; Streambank revetments     

车装焊复合加工装备的服役可靠性评估

目的评估某型航天用车装焊复合加工装备在服役过程中的服役可靠性。方法首先分析装备常见的故障模式,统计装备在使用过程中的故障数据,由于装备故障数据样本量较少,所以提出基于贝叶斯理论的小样本车装焊复合加工装备可靠性评估方法,其中通过马尔科夫链蒙特卡罗(MCMC)法抽样解决贝叶斯理论中后验积分复杂的问题。结果确定了车装焊复合加工装备的寿命威布尔分布模型,并运用贝叶斯方法,计算出该车装焊复合加工装备的平均无故障工作时间(MTBF)。结论评估结果略低于设计要求,原因是目前该装备处于服役初期,服役初期故障数据较多。待进入稳定服役期时,故障率会有一定程度的降低后趋于稳定,MTBF会有一定幅度的增加,所以该车装焊复合加工装备MTBF基本满足设计要求。