预制夹心保温外墙板温度场的有限元分析

西安市地区属于寒冷地带,在冬季工况下室内外温差很大,那么对于混凝土结构而言,在窗框与混凝土窗口连接处极容易发生漏热,甚至出现结露问题。为了研究预制夹心保温外墙板窗框安装所产生的热桥问题,本文通过运用ANSYS有限元软件对不同窗框安装位置下的外墙板进行了温度场以及热流密度场方面的模拟。通过对比分析,得出在第一种窗框安装位置下,预制夹心保温外墙板窗洞口周边的温度最高、漏热最少、保温节能效果最好。在第4种窗框安装位置下,预制夹心保温外墙板内表面窗洞口周边大面积区域的温度接近室内露点温度,严重影响室内热环境。文章对在不同窗框安装位置下的预制夹心保温外墙板进行了深入的研究分析,结论可以为西安地区混凝土结构热桥的保温研究提供一定的参考依据。     

QoS guided Min-Min heuristic for grid task scheduling

Task scheduling is an integrated component of computing.With the emergence of Grid and ubiquitous computing,new challenges appear in task scheduling based on properties such as security,quality of service,and lack of central control within distributed administrative domains.A Grid task scheduling framework must be able to deal with these issues.One of the goals of Grid task scheduling is to achivev high system throughput while matching applications with the available computing resources.This matching of resources in a non-deterministically shared heterogeneous environment leads to concerns over Quality of Service (QoS).In this paper a novel QoS guided task scheduling algorithm for Grid computing is introduced.The proposed novel algorithm is based on a general adaptive scheduling heuristics that includes QoS guidance.The algorithm is evaluated within a simulated Grid environment.The experimental results show that the nwe QoS guided Min-Min heuristic can lead to significant performance gain for a variety of applications.The approach is compared with others based on the quality of the prediction formulated by inaccurate information.