CAST工艺设计计算方法探讨

分析了目前国内CAST工艺采用的几种设计计算方法的共同之处、各自特点及存在的问题。在此基础上,结合多年实际设计运行经验,提出并推荐一种新的设计计算方法。该推荐方法以满足生物反应需要作为制约因素进行设计和计算,并根据生物处理目标所确定的泥龄和生产实际运行所能达到的混合液污泥浓度来推算污泥总量、反应池有效容积及其他设计数据,排除了凭经验设计计算的任意性。最后介绍了推荐方法在实际工程中的应用情况。     

西阜高速公路石家庄段弃渣场水保措施探析

针对西阜高速公路石家庄段建设过程中弃渣量大的实际情况,在分析弃渣场选址与治理思路的基础上,提出了工程措施、植物措施和临时拦挡措施相结合的综合防治体系,并对弃渣场水保措施进行典型设计。     

宽带钢厚度模型的研究与优化

介绍莱钢宽带钢厚度模型的优化,以改善板形,提高控制精度.     

Optimal blank design based on finite element method for blades of large Francis turbines

Metal pressing process that is widely used in industries has advantages over casting process for producing large Francis turbine blades from thick plates. Prior to the pressing process, blank design is firstly performed to determine flat blanks. The traditional trial and error approach is not applicable to blade design for Francis turbines that are not standard due to hydraulic characteristics of power plant sites. The rapid development of computing technology makes it possible to obtain optimal flat blanks by numerical modelling and simulation. In this paper, inverse finite element approach is investigated for blank design and an elasto-plastic model has been built using the well-known commercial software ANSYS. Numerical simulations for blade unfolding models with thick shell elements, solid elements and shell elements have given results with negligible differences. Unfolding tests with simple geometries have been carried out and the numerical results agree well with the analytical solutions. A large and thick shape of a Francis turbine blade for a hydropower plant has been successfully unfolded by inverse FE model. Sensibility analysis shows that the middle surface of the flat blank is independent of blade thickness. For ensuring the machining of the blade after the pressing process, a new contour is obtained by extending the boundary of the flat blank provided by the numerical model. This research may provide a useful tool for optimal blank design of Francis turbine blades.     

埋地钢管结构设计思路的探讨

主要通过对国内和美国手册关于埋地钢管不同的设计思路进行分析对照,尤其在不同工况、不同土弧包角及砂浆衬砌作用下对钢管壁厚设计的影响进行了探讨,可为其它工程设计提供借鉴。     

建筑内部给水管网设计秒流量计算常见问题分析及改进方法

设计秒流量的计算是管网水力计算的基础,是确定各管段管径、计算管道水头损失,进而确定给水系统所需压力的主要依据.选择正确的设计秒流量计算方法至关重要.例举建筑给水工程中设计秒流量计算出现的常见问题,并将Excel计算表格加以完善,形成第二类建筑的通用计算表格.     

微控制器中按键处理技巧及应用

针对微控制器中按键处理问题。列举不同场合对按键处理的设计优化。重点讨论了非编码键盘的抖动及干扰消除优化。结合ADC按键,设计一种新型软件滤波方法一阀值平滑滤波,详细介绍了其软硬件的实现过程。通过验证,此方法既能有效扩展键盘又能实现消抖,有效提高微控制器资源的利用。     

非圆曲线的数控处理及程序实现

引用优化设计中一维搜索和黄金分割法,针对数控加工中非圆曲线的处理,给出实用、简洁和新颖的宏程序实现方法,解决在数控系统中求解方程组的问题,是数控用户快速解决相关应用问题的有效手段。     

Truth-Telling Reservations

We present a mechanism for reservations of bursty resources that is both truthful and robust. It consists of option contracts whose pricing structure induces users to reveal the true likelihoods that they will purchase a given resource. Users are also allowed to adjust their options as their likelihood changes. This scheme helps users save cost and the providers to plan ahead so as to reduce the risk of under-utilization and overbooking. The mechanism extracts revenue similar to that of a monopoly provider practicing temporal pricing discrimination with a user population whose preference distribution is known in advance.     

Expected runtimes of evolutionary algorithms for the Eulerian cycle problem

Evolutionary algorithms are randomized search heuristics, which are applied to problems whose structure is not well understood, as well as to problems in combinatorial optimization. They have successfully been applied to different kinds of arc routing problems. To start the analysis of evolutionary algorithms with respect to the expected optimization time on these problems, we consider the Eulerian cycle problem. We show that a variant of the well-known (1+1)$(1+1)$ EA working on the important encoding of permutations is able to find an Eulerian tour of an Eulerian graph in expected polynomial time. Altering the operator used for mutation in the considered algorithm, the expected optimization time changes from polynomial to exponential.