Vehicle electrification in a developing country: Status and issue,from a well-to-wheel perspective

The increase of public attention, scientific research and political interest in environmental problems associated with transportation has provided the motivation for re-invention of electric vehicles. However the usage of grid-dependent EVs with a high-carbon electricity grid might produce more damage to the environment. This study aims to provide an environmental impact comparison of ICEVs, HEVs and EVs during their usage cycle, by modeling their energy consumption (electricity or fuel) and the supply chains of the supplied energy, (well-to-wheel) based on a life cycle assessment. The results show that running EVs with the existing mixed sources of electrical energy produce larger impacts on the environment 60% of the time; when compared to HEVs. When compared to ICEVs, EVs produce a larger environmental impact on 7 out of 15 environmental impact categories. Overall the environmental impacts of EVs are substantial based on the well-to-wheel analysis. It will continue to be so if no change is made to the methods of electricity generation in the near future. Given that the environmental profile of EVs is linked with the existing national electricity generation mix, the national electricity supply must be made cleaner before the electrification of the urban transport system.     

郊野公园雨水收集利用系统分析与设计——以三十岗郊野公园为例

郊野公园设计过程中需在系统性生态理念指导下,根据项目内的水系和地形条件设计雨水收集系统,结合实际项目需要选择合理的方案进行回用,达到经济效益及生态效益.经案例分析水量平衡体系、实现了良好的雨洪调蓄功能.景观水体的补水优先取自项目内收集回用的雨水,实现局部生态循环补水.在汇水坡面整齐、水塘较多的项目背景下,进行局部水系规...     

番禺区农村公路网规划的思路和布局方法

农村公路网规划的重点是解决农村出行问题,并以此搭建番禺区以高等级公路为骨架,以农村公路为辅助的层级公路网体系,该规划的实施,取得了良好的社会效应和经济效益,可作为其他类似地区低等级公路网规划的参考。     

公路工程文档管理的现状与发展趋势

本文分析了目前国内公路工程文档管理的现状,结合国内外文件档案管理的发展趋势,对公路工程文档管理的发展趋势做了探讨。     

从河源的实践看农村公路硬底化建设

文中结合河源市农村公路硬底化建设的实际情况,阐述了目前农村公路建设管理中存在的问题和在今后的建设管理中要坚持处理好的几个关系,以全面推进农村公路建设发展。     

美国的道路货物运输

美国的道路货物运输基本上是通过对车辆重量、尺寸的限制,危险品运输管理及超重检查等方面来实现对货物运输的管理,而这也是我国亟待完善的方式方法。     

高速公路景观与绿化设计的要点

我国的高速公路存在着一些景观问题,通过从“点”、“线”、“面”三个方面深入研究景观与绿化设计的方法．可以提高我国高速公路的建设和服务水平。     

国际集装箱运输市场回顾及展望

2005年的国际航运市场总体发展相对良好,就国际集装箱运输市场而言,2005年市场发展的主要特点表现为:世界经济稳步增长,市场供需情况良好,箱货贸易量与运力投放量同步上升,市场运价高位整理,船公司收益普遍增长,租船市场依旧抢手,中国因素成为世界海运的核心动力。展望2006年,虽然存在许多不确定因素,但出现重大突发性事件的可能性较小,预计国际集装箱运输市场有望继续处于强势发展周期。     

Empirical analysis of short period traffic counts and their efficiency: the case of Indian traffic

Short period traffic counts (SPTCs) are conducted routinely to estimate the annual average daily traffic (AADT) at a particular site. This paper uses Indian traffic volume data to methodically and extensively study the effect of four aspects related to the design of SPTCs. These four aspects are: (i) for how long, (ii) on which days should SPTCs be carried out, (iii) how many times, and (iv) on which months should SPTCs be carried out? The analyses indicate that the best durations for conducting SPTCs are 3 days (starting with a Thursday) and 7 days, for total traffic and truck traffic, respectively. Further, these counts should be repeated twice a year keeping a separation of two months between the counts to obtain good estimates of AADT at minimal cost. An additional outcome of this study has been the determination of seasonal factor values for roads in developing economies, like India.     

复合材料在汽车上的应用及发展趋势

综述了金属复合材料、陶瓷复合材料及连续纤维的SMC在汽车上的应用状况,并与传统的汽车材料在性能、特点等方面进行了比较,论述了复合材料在汽车上得到广泛应用的原因。对车用复合材料的发展趋势进行分析。