Drawn into Space: Zaha Hadid

Visionary New York architect Lebbeus Woods reviews the evolution of Zaha Hadid's work from the 1970s to the present. Tracking the shifts in her work from a Suprematist-informed fragmentation in the 1980s to a more contemporary fluidity and a preoccupation with complex curvilinearity, he throws light on the relationship between Hadid's drawing and her architecture. Copyright © 2008 John Wiley & Sons, Ltd.     

Investigation on wear behaviour of cryogenically treated TiAlN coated tungsten carbide inserts in turning

Cryogenic treatment has been ascribed as a way of improving the cutting life of tungsten carbide turning inserts. Most of the research conducted till date has not reported any effort to excavate the effect of cryogenic treatment on the performance of coated tungsten carbide inserts in terms of adhesion strength of coatings deposited on tungsten carbide substrate. In order to understand the effect of cryogenic treatment on the adhesion strength of coatings, a comparative investigation of the wear behaviour and machining performance of cryogenically treated coated tungsten carbide inserts in orthogonal turning has been carried out in this study. The commercially available TiAlN coated square shaped tungsten carbide inserts (P25) were procured and subjected to cryogenic treatment at two levels −110 °C (shallow treatment) and −196 °C (deep treatment) of temperature independently. The criterion selected for determining the turning performance was based on the maximum flank wear (0.6 mm) as recommended in ISO 3685-1993. The results showed that shallow cryogenically treated coated tungsten carbide inserts performed significantly better as compared with deep cryogenically treated and untreated inserts. Major outcome of the present study includes a substantial decrease in tool life of deep cryogenically treated inserts as compared to untreated inserts indicating the destructive effect of deep cryogenic temperature (−196 °C) on TiAlN coated inserts which is further supported by VDI-3198 indentation test.     

火灾中不锈钢柱和梁的屈曲

材料特性和它们对高温的反应构成结构防火设计的关键部分。当遇到高温时,与碳钢相比,不锈钢表现出更好的材料强度和刚度。尽管独立而言,强度和刚度都很重要,但是在高温作用下,它们之间的关系同样也会对结构构件的屈曲反应产生显著影响。检查了现有的试验结果,并且介绍了数值参数研究的结果,即利用ABAQUS对火灾中的不锈钢柱进行分析。由于对局部和整体初始几何缺陷的敏感,通过冷作和对柱端的局部保护可以提高焊脚强度。为探究局部横截面长细比、整体构件长细比和荷载变化的影响,还进行了参数研究。试验结果与现有设计规范欧洲规范3(part1.2),欧洲Inox/SCI设计手册中对结构不锈钢的规定及CTICM/CSM中提到的规定相对比。分析了在全部23个柱屈曲抗火试验中,6个短柱和6个梁的抗火试验结果。文中标出过度保守和互相矛盾的结果以及变形极值。通过修订,可以使得今后不锈钢梁和柱能在火灾中更有效的使用。改进后,柱的抗屈曲能力提高了6%,短柱的抵抗能力提高28%,平面内抵抗弯矩提高14%,高于现有欧洲规范的要求。     

应用FWD评价旧混凝土路面及加铺层设计

在混凝土路面上铺沥青面层是旧路改造的一种重要形式，但我国目前还没有相应的设计规范，使这种路面的设计带有经验性，缺乏科学的理论与依据。本文介绍应用落锤式弯沉仪（FWD）评价路面结构承载能力的方法及美国AASHTO旧混凝土路面上沥青加铺层设计方法。