New analysis of non-newtonian turbulent flowndashyield-power-law fluids

The writers' new analysis of non-Newtonian turbulent flow is extended to the yield-power-law model. As the value of the exponent of the yield-power law decreases from unity, the calculated friction factor begins by converging toward the Newtonian line at high velocity, then parallels it, and finally diverges downward. This prediction agrees with previously unexplained experimental results.     

MATHEMATICAL MODELING OF THROUGH-HOLE-PLATING IN ELECTROCHEMICAL MICROFABRICATION II. AXISYMMETRIC TWO-DIMENSIONAL CONVECTIVE MASS TRANSFER

Axisymmetrical, two dimensional mass transfer in a tube and a through-hole was studied. The elliptic convective-diffusion equation was solved numerically by taking into account both the axial and radial diffusion in the entrance region of an infinite tube. The whole mass-transfer region in a tube of finite length was also studied by dividing the domain into several regions according to different mass-transfer mechanisms. A similar analysis is then conducted for a through-hole geometry by assuming a modified Hagen-Poiseuille fluid pattern. Results show that mass-transfer rate in a through-hole is larger than that in a tube by approximately 10%. This is due primarily to faster fluid flow within the concentration boundary layer in a through-hole.     

塑料充模流动粘性模型研究

对多种塑料在不同温度下的剪切速率一稳态剪切粘度数据进行Cross粘性模型参数拟合，得到了表征材料粘度的模型参数(B，Tb，τ^*，n)。其拟合效果良好，能较准确地描述塑料熔体在一定剪切速率和温度范围内的粘流特性，为工程计算和塑料熔体模流分析提供了数据支持。结果表明，该方法有较广泛的适用性。     

基于B/S架构的高校物资管理系统设计与实现

物资管理信息系统作为企事业单位现代化管理的重要组成部分,对于提高管理效率和物资利用率有着不可替代的作用。通过对物资管理系统的架构、需求分析、流程控制、功能实现、关键技术的详细分析,研究基于Internet、B/S架构和.NET平台的物资信息管理系统,较好地解决了高校物资管理从计划、采购、入库、出库、使用等环节的管理问题,实现了企事业物资集约化管理的目标。     

BitTorrent网络节点间流量的数据采集和分析

BitTorrent网络流量占据了互联网总流量的很大比例,吸引了大量专家学者的专注,然而现有实测工具无法实时记录BT网络中节点间的流量交互情况,有关真实BT网络中节点间流量的研究很少。建立了一个BT网络节点间流量的数据采集系统,将其部署在全球性实验平台Planetlab之后得到了真实数据,并验证了数据的正确性。通过对实测数据的分析和研究发现:(1)Tracker服务器在为各下载节点随机返回邻居节点列表时会受到各节点入网时间的影响;(2)50%以上的下载节点从种子处下载的数据为零,大部分下载节点的数据下载对种子的依赖性不大,从而深刻地体现出P2P应用模式的优越性。     

容器设计中搅拌装置的轴向力分析

搅拌装置在化工厂中应用很广，在磷肥、钛白粉装置中（15kt/a)使用较多，仅钛白粉装置中就大约有40－50台，如增稠结晶器，中和槽等，搅拌操作所涉及的因素极为复杂，浆叶形式的选择，从力学的观点来说，迄今研究不够，本文就搅拌装置产生的轴向力问题进行了初步研究。     

基于控制流模型的Web系统测试方法研究

Web应用系统的使用与日俱增,技术层出不穷,但是Web应用系统的测试却是一个难点.论文提出一种基于控制流的测试方法,对Web应用系统建立控制流模型,并给出形式化的定义,采用模型进行测试用例的产生.为了使测试自动化,论文还谈到脚本技术和测试执行器的设计.     

小型轴流压气机清洗两相流场的数值模拟

针对某小型航空发动机单级轴流压气机的清洗需求,以数值模拟结合实验的方法对压气机清洗流场的各种参数进行了分析研究.在初步确定清洗方案的基础上,建立了基于S-A湍流模型的离散相数值模拟理论模型,以经验公式估算喷嘴形成的初始液滴分布,并对喷嘴的实验参数进行了校准,最后以CFD软件进行了流场的数值模拟,计算结果表明：清洗液滴不会对压气机的流场产生明显影响,平面扇形喷嘴在该小型压气机上能获得较好的清洗效果.     

A reactive extension of the OpenMusic visual programming language

Objectives: OpenMusic (OM) is a domain-specific visual programming language designed for computer-aided music composition. This language based on Common Lisp allows composers to develop functional processes generating or transforming musical data, and to execute them locally by demand-driven evaluations. As most historical computer-aided composition environments, OM relies on a transformational declarative paradigm, which is hard to conciliate with reactive data-flow (an evaluation scheme more adequate to the development of interactive systems). We propose to link these two evaluation paradigms in the same and consistent visual programming framework.Methods: We establish a denotational semantics of the visual language, which gives account for its demand-driven evaluation mechanism and the incremental construction of programs. We then extend this semantics to enable reactive computations in the functional graphs.Results: The resulting language merges data-driven executions with the existing demand-driven mechanism. A conservative implementation is proposed.Conclusions: We show that the incremental construction of programs and their data-driven and demand-driven evaluations can be smoothly integrated in the visual programming workflow. This integration allows for the propagation of changes in the programs, and the evaluation of graphically designed functional expressions as a response to external events, a first step in bridging the gap between computer-assisted composition environments and real-time musical systems.     

Controller design for nonlinear systems using the Contoured Robust Controller Bode plot

In this paper, we develop the Contoured Robust Controller Bode (CRCBode) plot and demonstrate its use in the design of robust controllers for nonlinear single‐input single‐output (SISO) systems. The CRCBode plot shows contours (level sets) of a robust performance quantity on the Bode magnitude and phase plots of the controller. An iterative frequency domain loop‐shaping design approach is employed to eliminate all intersections of the controller frequency response with certain ‘forbidden regions,’ indicating that a standard SISO robust stability and performance criterion is satisfied. Nonlinearities are accounted for by avoiding the maximum forbidden regions over a structured uncertainty set consisting of linearizations of the system dynamics about several operating points. We demonstrate this technique by designing and experimentally verifying a flow‐rate controller for a butterfly‐valve based liquid cooling system, which is robust to valve nonlinearities and flow disturbances. Finally, we compare this compensator with one generated using an automated H _∞ synthesis algorithm and discuss the advantages of the CRCBode approach. Copyright © 2013 John Wiley & Sons, Ltd.