Factory solvent seaming

Factory solvent seaming is the method and process whereby several rolls of material, varying in width from 60 to 76 in (1·52 to 1·93 m), and weight from 900 lb to 1200 lb (4· to 5·3 kN) each are joined (fabricated) under controlled factory conditions into large panels.     

Coextruded HDPE/VLDPE multilayer geomembranes

High density polyethylene (HDPE) geomembranes have been used extensively during the last decade and very low density (VLDPE) geomembranes have been introduced during the last few years. Both materials have properties that are desirable for particular applications. HDPE has excellent chemical resistance, UV resistance and high modulus. VLDPE is very flexible and is capable of much more elongation in field applications than HDPE.

A geomembrane made by the coextrusion of HDPE and VLDPE has several advantages over geomembranes made from either HDPE or VLDPE alone for many applications. These advantages are realized due to synergistic effects that occur between the two polymers, resulting in a product that incorporates desirable properties of the two materials and eliminates some of the less desirable ones. The Coextruded Multilayer Sheet (CEMS) addressed in this paper has better tensile strength, tear resistance, seam strength, chemical resistance, permeability and UV resistance than VLDPE and better puncture resistance, elongation and stress crack resistance than HDPE. Coextruded, multilayer geomembranes make available more options for the design engineer attempting to find the best product for a given application.     

MDPE/VLDPE materials development

Medium density polyethylene (MDPE) and very low density polyolefins (VLDPE) are becoming the materials of choice in a wide range of geomembrane applications. Excellent inherent properties in chemical resistance and mechanical strength make MDPE the preferred material for demanding chemical environments. VLDPE's unique combination of toughness and flexibility enables the design of systems that can provide outstanding durability even under extreme climatic conditions. This paper describes key material properties of MDPEs and VLDPEs and discusses their influence on field performance.     

Emerging methods for geomembrane seaming

Selected geomembrane sheet seaming methods which are not widely used at the present time are discussed in this paper. These include ultrasonic bonding, electrical conduction bonding and electromagnetic induction bonding methods.

The physical principles of each of these techniques are discussed, as well as their current degree of development and implementation. The potential advantages and disadvantages of the methods are discussed.     

Basic considerations needed to ensure proper geotextile seaming

This paper examines the components of seaming as they relate to a sewn geotextile seam, as opposed to mechanical or chemical seaming techniques. Items of interest in this regard include: base geotextile properties, seam and stitch geometry, thread type, and sewing equipment. The importance of each item and the interaction between components are explored.     

Technical note on hot air seaming of high-density polyethylene geomembranes

Hot air fusion welding is widely used as a secondary seaming method for welding high-density polyethylene (HDPE) geomembranes, although seldom as a primary seaming method. This method is based on a very simple principle and can withstand comparison with the other main seaming methods. However, the strength and long-term durability of seams made with this method are still poorly known, and should be explored, as compared to the other welding methods.     

高强度三元乙丙防水片材接缝胶粘剂

以改性丁基橡胶为主体材料，研制了一种三元乙丙防水片材接缝用接触型单组分胶粘剂，并测试了其性能，同时与其他常用胶粘剂作了比较。     

高速公路大修接缝技术浅析

对国内外几种不同的接缝技术进行了探讨,并详细介绍了沥青路面大修工程中常见的纵向冷接缝、横向接缝的施工工艺、碾压方式及接缝的位置和形式等,以期为我国的高速公路大修接缝施工提供指导。     

Addressing the special concerns of landfill closures: VLDPE and textured geomembranes

Landfill closures often require a somewhat different set of properties for synthetic liners than do landfill bottom liner installations. In particular, cap design usually presents the geotechnical engineer with greater concerns regarding long-term slope stability and accommodation of differential settlement. Friction between synthetic liners and materials contacting those liners, multiaxial elongation, and flexibility increase in importance. Since leachate does not contact the liners, chemical resistance becomes less important. Resistance to the components of landfill gas is, in most cases, all that is necessary.

As a result, synthetic liners with a textured surface to improve friction angles, and very low density polyethylene (VLDPE) geomembranes are becoming very attractive to geotechnical engineers. They provide considerable improvement in those areas which are important for cap installation. These materials, however, behave differently in standard index and performance testing of geomembranes, when compared with traditional polyethylene liners. These behaviors and differences are important for geotechnical engineers to understand. They are discussed in this paper.     

场域、田野、在场 2015年米兰世博会中国馆三读

文章从"field"一词的三个不同含义,即场域、田野、在场出发,解读2015年米兰世博会中国馆。包括在中国馆整体规划及建筑设计中"场域"的理念;中国馆在世博会中的身份展示与代表,及其对本届世博会主题的诠释;现场的参数化建造。     

体育中心棒球场

体育中心棒球场,位于体育中心用地西侧,为临时建筑。在重大国际赛事结束后拆除,还原为文体活动区域。体育中心棒球场共有15000个坐席,在国际棒联的强烈要求下将其分为12000座（1号）和3000座（2号）两个棒球场,与训练场一起组成三个场地并由南向北线性排列,总建筑面积14360m^2。1号,2号场地包含运动员,裁判、赛事管理、VIP、媒体及安保等各类奥运比赛所需的功能用房,     

场 编辑手记

在刚刚结束的2008北京奥运会期间,北京的餐饮业获得了巨大的成功。据说,大名鼎鼎的兰会所在奥运期间有5000万进帐,刚刚开业不久的前门23号也门庭若市,达官贵人云集,蔚为壮观。"民以食为天"、"饮食男女,人之大欲",     

枕头地

这个永久性的土方项目覆盖了1486㎡的坡地,位于新修的人行坡道之间的交叉地带,而这些人行坡道又将混入住宅区的＂绿桥＂和西南98号大街的中央商务区连接起来。     

企业园地

凯斯挖掘装载机诞生50周年暨CXB系列液压挖掘机发布会;斯工程机械（上海）有限公司扩建;凯斯体验营CEC全国路演即将开始;CXB系列新型“会思考”挖掘机。     

塞菲科球场

新建的城市体育场强烈地唤起了人们心中对棒球运动情有独钟的回忆，同时也为球迷提供了一个感觉舒适，亲密和兴奋的比赛场地。在体育场设施的任何地方，不管是坐在看台上，买热狗或者只是在找坐位，整个场地都会让人在视觉上有一派磅礴大气之感。项目的设计继承了传统和历史的无形资产，创造了一个杰出的城市建筑，其中所表达的人文元素，     

Northala Field

该项目位于诺索尔特·格林福德郊野公园（郊野公园位于伦敦西部地区、占地面积100万平方米）的腹地,占地面积185000m^2.该项目在保留了郊野公园原有设施及特色的同时,使公园设施更加完善,特点更加鲜明。     

美国先锋派景观设计事务所

美国著名的景观设计师詹姆斯·科纳于1998年创立了Field Operations景观设计事务所（以下简称FO）。近年来FO在各类项目,特别是在大尺度的方案中,提出许多大胆的设计概念,特点鲜明,备受关注,逐渐成为景观和城市设计业界的领军团队。目前事务所由将近30位专业精英组成,他们大多拥有景观设计,城市设计、建筑设计、交流艺术等多重学科的专业背景。     

真空管太阳能集热系统温度场、速度场模拟

采用三维数学及物理模型对真空管太阳能集热系统的温度场、速度场进行了模拟。集热系统内流体由上升的热流体和下降的冷流体组成,接近蓄热水箱的真空管存在冷热流体混合的回流区。蓄热水箱内呈现明显的温度分层,水箱上部的流体被来自真空管的热射流加热,下部存在一个滞留区,只能通过导热传热。