2003年度国际市场最大225家承包商和200家设计公司市场分析

本文介绍了美国<工程新闻纪录>周刊所做的2003年度国际市场225家最大承包商和200家最大设计公司的排名情况,并对这一排名进行了分析和对比.2003年,种种的不确定因素开始明朗化,被压抑的需求开始释放,被推迟的项目逐渐解禁,整体经济形势的好转带动了建筑业的增长.2003年度的225强国际承包商和200强设计公司的营业额与去年相比都有较大的增长.中国承包商进入225强的有47家,设计公司进入200强的也达到了历史性的12家,营业额比去年也有了较大的增长,但相对于国际市场的快速增长,中国的份额仍有待提高.文章的最后分析了当前国际市场新趋势.     

2004年度国际市场最大200家设计公司市场分析

本文介绍了美国<工程新闻纪录>周刊所做的2004年度200家最大设计公司的排名情况,并对这一排名进行了分析和对比.2004年度的200强设计公司的营业额与去年相比有较大的增长.中国设计公司进入200强的达到了历史性的13家,营业额与去年相比基本持平,没有较大突破,相对于国际市场的快速增长,中国的份额仍有待提高.     

Empirical tests for identifying leading indicators of ENR Construction Cost Index

Engineering News-Record (ENR) publishes its Construction Cost Index (CCI) monthly. CCI is the weighted average price of construction activities in 20 United States (US) cities. CCI has widely been used for cost estimation, bid preparation and investment planning. Cost estimators and investment planners are not only interested in the current CCI, but also are interested in forecasting changes in CCI trends. However, CCI is subject to significant variations that are difficult to predict. An important step towards forecasting CCI trends is to identify its leading indicators. The research objective is to identify the leading indicators of CCI using empirical tests. The results of Granger causality tests show that consumer price index, crude oil price, producer price index, GDP, employment levels in construction, number of building permits, number of housing starts and money supply are the leading indicators of CCI. The results of Johansen’s cointegration tests show that money supply and crude oil price are the leading indicators with long-term relationships with CCI. These findings contribute to the body of knowledge in CCI forecasting. CCI can be predicted more accurately using its leading indicators. Cost estimators and capital project planners can benefit from better forecasting through reduction in uncertainty about future construction costs.     

The Effect of Accelerator/Sulphur Ratio on the Cure Time and Torque Maximum of Epoxidized Natural Rubber

Abstract

The cure time of accelerated sulphur vulcanization of Epoxidized Natural Rubber (ENR 25) was studied while one grade of unmodified natural rubber– Standard Malaysian Rubber Light (SMR L) was used as a control. Five accelerators, viz. 2-mercaptoben-zothiazole (MBT), tetramethylthiuram disulphide (TMTD), zinc dimethyldithiocarbamate (ZDMC), N-tert-butyl-2-benzothiazylsulphenamide (TBBS) and diphenylguanidine (DPG) were used in the study and the vulcanization systems used were conventional vulcanization (CV), semi-efficient vulcanization (semi-EV) and efficient vulcanization (EV). Monsanto Moving-Die Rheometer (MDR 2000) was used to determined the cure time in the temperature range of 100-180°C. The results indicate that cure time decreases exponentially with increasing temperature for the two rubbers studied. At a fixed curing temperature, ENR 25 shows shorter cure time compared to that of SMR L. This has been attributed to the activation of the double bond by the adjacent epoxide group in ENR 25. Studies of the effect of varying amounts of M Bata a fixed sulphur concentration show that cure time decreases as the accelerator concentration increases. ENR 25 shows higher torque maximum than SMR L. This observation can be related to the oxirane group which is bulky and thus accounts for increased glass; transition temperature with increase in the level of epoxidation. Of the vulcanization systems, CV shows the highest torque maximum followed by semi-EV and than EV. This trend can be attributed to the amount of active sulphurating agent which increases with increasing accelerator concentration. It was also found that the influence of accelerator/sulphur ratio becomes less significant as vulcanization temperature increases.     

国际工程承包市场竞争环境量化分析

金融危机引起的经济衰退极大地影响着国际工程承包市场的竞争环境。提出利用ENR发布的数据计算贝恩指数和相对市场占有率(RSOM)指数,结合兰查斯特法则(Lanchester's Law)量化分析竞争市场的结构、区域市场的竞争强度、竞争对手的分布,有针对性地提出中国工程企业的应对措施。     

环氧化天然橡胶对白炭黑/天然橡胶硫化胶物理性能和减震性能的影响

研究不同环氧度环氧化天然橡胶(ENR)对白炭黑/天然橡胶(NR)硫化胶物理性能、减震性能及压缩疲劳生热性能的影响。结果表明:ENR可以提高白炭黑/NR硫化胶的物理性能和实用温度范围内的阻尼性能,降低硫化胶的压缩疲劳生热,其中环氧度为40%的ENR效果最优。     

2005年度国际市场最大225家承包商市场分析

在回顾美国《工程新闻纪录》周刊所作的2000-2005年国际市场最大225家承包商的市场情况的基础上,重点介绍了2005年度国际市场225家最大承包商的排名情况,并对这一排名进行了分析和对比.2005年度225强承包商的国际市场营业额继续以较快的速度增长.中国承包商进入225强的有46家,营业额与去年相比有较大增长,市场份额略有上升,但相对于国际市场的快速增长,中国的份额仍有待提高.     

Thermomechanical properties and shape memory effect of epoxidized natural rubber crosslinked by 3‐amino‐1,2,4‐triazole

A thermally induced shape memory polymer based on epoxidized natural rubber (ENR) was produced by curing the ENR with 3‐amino‐1,2,4‐triazole as a crosslinker in the presence of bisphenol‐A as a catalyst. Dynamic mechanical and tensile analysis was conducted to examine the variation of glass transition temperature, stiffness, and extensibility of the vulcanizates with the amount of curatives. Shape memory properties of the ENR vulcanizates were characterized by shape retention and shape recovery. It was revealed that the glass transition temperature of the ENR vulcanizates could be tuned well above room temperature by increasing the amount of curing agents. Also, ENR vulcanizates with T_g higher than ambient temperature showed good shape memory effects under 100% elongation, and the response temperatures of the recovery were well matched with T_g of the samples. Copyright © 2006 Society of Chemical Industry     

煤矸石粉作环氧化橡胶补强填充剂的研究

对废弃煤矸石进行了磨碎、焙烧和表面活性处理后作为环氧化天然橡胶（ＥＮＲ） 的补强填充剂． 对这种新型ＥＮＲ 填充剂的补强机理进行了分析， 讨论了影响其性能的主要因素． 研究了填充剂用量对ＥＮＲ 的流变性能、硫化特性和动态力学等的影响． Ｌｅｅ 方程计算结果表明：煤矸石经偶联剂处理后， 明显提高了在ＥＮＲ 胶料中的分散程度．     

2015 年度全球最大承包商及中国上榜公司解析

基于ENR 公布的2015 年度全球最大承包商数据,对全球250 强承包商的营业收入、业务范围、区域分布进行了分析;基于历史数据,针对近5 年全球最大承包商的区域经营情况,分析了2015 年度入榜中国内地公司的排名、上榜数量、业务收入情况;对近5 年全球10 强承包商和位于10 强的中国内地公司经营状况进行了分析。通过分析,对明年全球最大承包商的营业收入变化趋势进行预测,指出了中国内地承包商的优势和劣势。