The orthogonal meshless finite volume method for solving Euler–Bernoulli beam and thin plate problems

In this paper a new method untitled “orthogonal meshless finite volume method” (OMFVM) is developed for solving elastostatic problems in Euler–Bernoulli beam and thin plate. In this method, the weak formulation of a conservation law is discretized by restricting it to a discrete set of test functions. In contrast to the usual finite volume approach, the test functions are not taken as characteristic functions of the control volumes in a spatial grid, but are chosen from a Heaviside step function. The present approach eliminates the expensive process of directly differentiating the OMLS interpolations in the entire domain. This method was evaluated by applying the formulation to a variety of patch test and thin beam problems. The formulation successfully reproduced exact solutions. Numerical examples demonstrate the advantages of the present methods: (i) lower-order polynomial basis can be used in the OMLS interpolations; (ii) smaller support sizes can be used in the OMFVM approach; and (iii) higher accuracies and computational efficiencies are obtained.     

江苏建筑职业技术学院图书馆空调系统三维绘图的运用

简要介绍了该工程空调系统设计方案。结合工程设计体会,总结了三维绘图软件的优势与不足,以及应用该软件后设计思路的调整。     

Studies on the heating capacity control of a multi-type heat pump system applying a multi-input multi-output (MIMO) method

This paper describes a method to control capacity of a multi-type heat pump system. Because indoor units are interconnected, alteration of the heating or cooling setting of one indoor unit can influence the performance of the other indoor units. Proportional-integral (PI) controllers were used to assess system performance, and the PI controllers’ gain values were optimized by using a genetic algorithm. A system model was established following a system identification optimization process, and a pseudo random binary sequence was selected as the system identification input signal. A multi-input multi-output (MIMO) controller was more effective in reducing such cross-coupling effects than a single-input single-output (SISO) controller. The temperature at the secondary fluid outlet in the condenser and the saturation pressure at the evaporator were selected as the control variables in the MIMO controller. The experimental results showed that an optimized MIMO controller could reduce overshoot by up to 40% compared with the results using a SISO controller.     

《固定式压力容器安全技术监察规程》中压力容器类别的划分

TSG R0004—2009《固定式压力容器安全技术监察规程》中压力容器类别划分按设计压力、容积和介质危害性三个因素确定,不再考虑容器在生产过程中的作用、材料强度等级、结构形式等因素。根据危险程度的不同,仍然划分为Ⅰ类、Ⅱ类、Ⅲ类,在不同介质分组坐标图上查取相应的类别,简单易行、科学合理、准确唯一。并将介质分为两组,一组为危险性介质;另一组为非危险性介质。按介质组别分类图确定压力容器类别,将分类图分区域可以迅速确定压力容器类别根据强化危险性原则,突出本质安全思想,笔者认为对第二组介质的类别划分有些部分不太合理,根据目前的划分方法,某些压力容器的容积相差1 L或压力相差0.01 MPa,可压力容器类别却从Ⅲ类压力容器变成了Ⅰ类压力容器,建议将这范围内的类别划分从Ⅰ类压力容器改为Ⅱ类压力容器。     

大体积砼裂缝成因及控制技术措施

针对大体积砼温度裂缝问题,首先分析了大体积砼温度裂缝产生的原因,并提出了相应的控制技术措施。     

龙耀路越江隧道通风系统设计

根据龙耀路越江隧道分期实施投入运营的情况,介绍了隧道通风系统设计。接着介绍了通风设备配置情况。最后分析了隧道峒口内环境,经计算,CO浓度均满足设计标准。     

同源高速宏观地质条件对勘察的指导意义

对同源高速公路地貌景观进行了分析,并针对不同地质条件下的工程地质特征进行了工作量布置前的探讨,综合研究后进行了勘察工作,合理指导了勘察与工程建设,对同类工程具有重要的指导意义。     

Transient phenomena of current and field distortion due to dynamics of packet‐like charges in LDPE films

Simultaneous measurements of space charge and external current were carried out using a PEA measurement system with an electrometer on the back of a grounding electrode in order to clarify the physical situation of a huge packet of positive space charges in LDPE films. A large number of positive charges from a semiconducting anode were accumulated at the interface between LDPE and an Al‐cathode at a mean applied field of 1.5 MV/cm and then finally disappeared. The results of simultaneous measurements showed that the external current kept a relatively high value during charge accumulation and further increased when the charges disappeared. Both the charge dynamics and the external current were restricted by addition of a low‐molecular‐weight paraffin wax, indicating that carrier transport was influenced by the microstructure of the polymer. The dynamics of the residual charges after short‐circuiting is also discussed. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(4): 10–17, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21256