Safe pedestrian crossings for children and elderly

In May 2000, the Swedish code governing the conduct of drivers at marked crosswalks became stricter with the intent to improve safety and mobility for pedestrians. A crash analysis based on a macro study of all of Sweden suggests that the injury risk in marked, not reconstructed, crosswalks increased by 27% for pedestrians and 19% for bicyclists. The reason for this may be that pedestrians get a false sense of safety with the new code. Reconstructions aiming at lowering speeds are indeed needed for the change of code to be positive. The 90-percentile speed should not exceed 30 km/h or safety will deteriorate. However, low speed by itself may not guarantee optimal safety. Safety can be further improved at sites, which already have been reconstructed to ensure low speeds. Results based on field data collected at sites close to schools in Malm?, Trollh?ttan and Bor?s in Sweden, and in-depth studies and other analyses of Finnish and Swedish police-reported crashes, suggest that safety of children and elderly is further improved at sites where visibility, orientation and clarity are sufficient. Also, marking crosswalks may increase yield rates (expected improvement 6%) towards pedestrians; and speed cushions situated at a longer distance from the marked crosswalk increase yield rates towards pedestrians and cyclists compared to speed cushions closer by.     

关于复合地基中褥垫层的作用

结合多年的工程实践，对复合地基的组成进行了介绍，阐述了在复合地基的设计和施工中褥垫层的作用，最后对褥垫参数的确定做了分析，以供今后类似工程参考借鉴。     

Tensile Structure Design An Engineer's Perspective

Here, David Wakefield, the founder of Tensys, an engineering consultancy that specialises in lightweight fabric structure analysis, describes the leading principles that underlie tensile structure design. He explains not only the application of materials and the importance of detailed stress analysis, but also where future developments might lie in this field. Copyright © 2006 John Wiley & Sons, Ltd.     

高层建筑中长螺旋钻孔压灌素混凝土桩的应用

分析了长螺旋钻孔压灌素混凝土桩的加固原理,介绍了长螺旋钻孔压灌素混凝土桩的设计方法,并通过工程实例进行了说明,指出高层建筑基础采用长螺旋钻孔压灌素混凝土桩复合地基是一种行之有效的地基处理方法。     

Structuring Strategies for Complex Geometries

Over the last couple of decades, computation has proved a great facilitator for design, allowing far greater scope for analysis and generative design. Intelligent engineering, though, can only be truly set apart by the pursuit of the right design strategy, as outlined here by Wolf Mangelsdorf of Buro Happold. Mangelsdorf highlights four different models that enable the generation and engineering of geometrically complex forms and describes how they have been applied by Buro Happold in four very diverse projects with different architect collaborators. Copyright © 2010 John Wiley & Sons, Ltd.     

兰西县亚麻汽车座垫产业集群发展研究

从黑龙江省兰西县亚麻汽车座垫产业集群继续发展所面临的问题入手,分析了集群持续创新动能不足、全民创业内存质量不高、原料供应不稳、融资渠道欠缺、产业集群成长的产业协作与关联度低下等阻碍集群进一步发展的因素,并指出背后深层次的原因在于其创新机制的不完善、产业集群发展战略与核心竞争能力的缺乏、人力资源素质的欠缺和金融的缺口,并认为应在县政府与集群自身的积极努力下,建立政策支持体系、集群人力资源平台、保证原料供应平台与完善产业分工协作网络平台,自主创新,走继续发展之路.     

Effect of initial pre‐compression of corrugated paperboard cushions on shock attenuation characteristics in repetitive impacts

The use of paper as a cushioning material is motivated by its environmental advantage over polymeric materials such as expanded polystyrene. Various studies have been conducted to investigate the capability of corrugated paperboard (CPB) to act as cushioning materials for protective packaging. The studies have normally focused on performance of cushions and effects of climatic conditions on the shock attenuation in the first drop. However, no information is available to show that CPB can be engineered to produce a cushioning element with good shock attenuation in repetitive impacts. This study investigates the deterioration of the shock attenuation characteristics of CPB cushions in consecutive impacts. A series of cushion‐test style experiments on multilayer cushion pads made entirely from CPB were conducted. Each cushion was first subjected to 20 impacts, followed by simulated warehousing in a climatic chamber, and then the additional 15 impacts. The effect of initial pre‐compression strain introduced in the process of making cushion pads is discussed and demonstrated. The performance of cushions was judged not only by the maximum acceleration of shocks. Entire recorded shock pulses and calculated corresponding shock response spectra were analysed and are presented as 3D maps in order to reveal trends that occur when a cushion is subjected to multiple drops. The paper shows that the level of pre‐compression has an important effect on the degree of deterioration of cushion performance after multiple drops. As an example, the maximum acceleration for a pad pre‐compressed to 95% strain increased by less than 20% between the 1st and the 35th drop. In contrast, for 80% pre‐compression, the increase was 300%. It was found that the selection of optimum static stress should be made in conjunction with the expected number of impacts in order to optimize the cushion performance. Copyright © 2009 John Wiley & Sons, Ltd.     

石粉垫层的工程应用实例

建筑地基处理在结构设计中是一个非常重要的环节 ,处理方案的优劣 ,不但影响到建筑的结构安全 ,而且也直接影响到工程投资和工期 .石粉碾压垫层作为近年出现的一种新的地基处理方法 ,具有技术先进、经济合理、安全适用、工期短、承载力高等特点 .笔者通过一个工程实例 ,论述了其对于软弱地基处理的一些特点 ,提出既要保证安全 ,又要讲求经济合理的观点     

顶空-气相色谱法测定汽车座垫中总碳挥发量

建立了顶空-气相色谱仪测定汽车座垫中总碳挥发量的方法 ,通过优化顶空瓶加热温度、平衡时间、进样口温度、检测器温度参数,在仪器最佳条件下,线性范围0.5g/L-10g/L,相关系数R2=0.9997。该方法用于汽车座垫中总碳挥发量测定,操作简单快速,准确度高。     

夏季汽车坐垫面料开发

介绍了开发夏季汽车坐垫面料的纤维种类和特性,包括亚麻纤维、黏胶纤维、竹原纤维和竹炭纤维,以及开发面料选用的织物组织种类和特性,包括纬编珠地织物、经编网眼织物和间隔织物。