寒冷地区写字楼围护结构热工性能优化

以某典型写字楼为模型,利用DeST-C软件对寒冷地区三个城市的建筑能耗进行了模拟,分析了不同保温层厚度和窗户类型对建筑能耗的影响,为当地的节能改造提供了参考依据。     

基于最小熵解卷积的齿轮箱早期故障诊断

齿轮箱发生早期故障时,其振动信号一般很微弱,且隐含的能反应出齿轮箱运转状态的冲击成分常被淹没在强烈的噪声中,直接做频谱分析或包络谱分析,很难提取其故障特征。论文将最小解卷积方法应用于炼胶机的齿轮箱故障诊断。首先利用该方法对齿轮箱振动信号进行解卷积滤波处理,然后对滤波后的信号进行包络解调分析,最后提取出了该齿轮箱轴5上齿轮8(z8=28)齿根轻微裂纹的故障特征,实现了该齿轮箱的早期诊断。应用实例验证了最小熵解卷积方法的有效性和优点。     

基于排列熵的电磁声发射信号到达时间识别

排列熵算法简单高效,能够反映出信号的微小变化,是一种有效的信号突变检测工具。通过引入信号包络排列熵分析方法,对声发射信号到达时间识别问题进行求解。排列熵对信号幅值的大小不敏感,但对信号幅值的变化敏感,通过记录信号包络排列熵的变化,根据包络排列熵第一个极小值时刻来识别信号到达时间。根据裂纹电磁声发射实测信号识别结果可知,包络排列熵方法对声发射信号到达时间具有较高的识别精度。     

近零能耗建筑中相变建筑材料的研究进展

近零能耗建筑是采用被动式建筑设计和主动式节能技术、以最低的能源设备功耗获得舒适室内环境的建筑。相变建筑材料的使用可以提高建筑围护结构的热惰性,减少室内温度的波动,降低供暖、空调设备的容量,同时能与太阳能、空气能等可再生能源相结合,降低建筑设备能耗。从不同围护结构的角度介绍了相变建筑材料的分类与特点,综述了国内外相变围护结构的研究进展,列举了相变建筑材料在近零能耗建筑中的被动式设计案例。分析了相变建筑材料的研究方向,以及相变建筑材料在被动式设计和主动式节能技术上的发展趋势,为近零能耗建筑的研究和设计提供参考和依据。     

现场测量建筑围护结构节能特性的问题分析

通过实际建筑围护结构热工性能现场检测总结了一些客观存在的问题,针对这些问题提出了解决问题的方法,并针对相关标准提出了改善的建议。     

Determination of worker physiological cost in workspace reach envelopes

Oxygen uptake (VO₂), heart rate (HR) and myoelectric activity (EMG) were measured while performing a repetitive task in the normal, maximum and extreme workspace reach envelopes. The VO₂ and HR increased significantly from the normal to the maximum to the extreme workspace reach envelope. The average increases in VO₂ when compared to the normal workspace were 19 and 52%, respectively. The corresponding average increases in HR were 6 and 14%, respectively. The increase in EMG for anterior deltoid, upper trapezious and erector spinae showed a significant increase from normal to maximum and from maximum to extreme workspaces. The average increases in EMG for anterior deltoid, upper trapezious and erector spinae, compared to the normal workspace were 96, 37 and 48% respectively for the maximum workspace and 193, 95 and 106% for the extreme workspace, respectively. The research indicated for the first time that during task performance, worker physiological cost would increase significantly with the increase in workspace reach levels.     

Improving energy efficiency through the design of the building envelope

Buildings, their surroundings and related enterprises produce more CO₂, generate more pollution, consume more energy, and waste more natural resources than any other human enterprise or industry. Moreover, considerable parts of these environmental impacts are the results of the lodging industry [1].