Railway transportation and environmental efficiency in China

Railway is one of the most efficient and environmental-friendly ways to transport people and goods. High-speed railway has been developing rapidly and the railway mileage has increased by 21.18% in China during the period of 2006–2011 and thus it is interesting to evaluate whether the railway transportation has reduced the environmental impact of transport in China. In this paper, we first use a non-radial DEA under managerial disposability to measure the environmental efficiency of 30 regions in China; then we propose a panel beta regression with fixed effects to model the impact of railway transportation on environmental efficiency. The results indicate that the environmental efficiency slowly increased during 2006–2011 and it exhibits regional disparities with the eastern area having the highest environmental efficiency and the western area being the lowest one; Moreover, we also find a significant positive impact of railway transportation on higher environmental efficiency.     

Changes to commute mode: The role of life events,spatial context and environmental attitude

It has been suggested that commuting behaviours become habitual and that changes to commute mode are more likely at the time of major life events. However, evidence to support this has so far been limited to analyses of small-scale samples. To address this evidence gap, we use two waves of panel data from the UK Household Longitudinal Study (2009/10 and 2010/11) to identify and explain the prevalence of individual change in commute mode from year to year amongst a representative sample of the English working population (n = 15,200). One third of those that cycle or get the bus to work, and one quarter of those that walk to work, are shown to change commuting mode by the following year. Car commuting is more stable, with only one in ten car commuters changing mode by the following year. Commute mode changes are found to be primarily driven by alterations to the distance to work which occur in association with changing job or moving home. Switching to non-car commuting becomes much more likely (9.2 times) as the distance to work drops below three miles. High quality public transport links to employment centres are shown to encourage switches away from car commuting and mixed land uses are shown to encourage switches to active commuting (walking and cycling). Switches away from car commuting are found to be more likely (1.3 times) for those with a pro-environmental attitude. The attitude orientation is shown to precede the behaviour change, demonstrating evidence of ‘cause and effect’. Overall, the study shows that changes in commuting behaviour are strongly influenced by life events, spatial context and environmental attitude.     

Over-reporting vs. overreacting: Commuters’ perceptions of travel times

In a large-scale, real-life peak avoidance experiment, we asked participants to provide estimates of their average in-vehicle travel time during their morning commute. After comparing the reported travel times with the actual corresponding travel times, we found that the average travel times were overstated by a factor of 1.5. We showed that driver- and link-specific characteristics partially explained these exaggerations. Using the stated and revealed preference data, we investigated whether the driver-specific reporting errors were consistent with the drivers’ scheduling behaviors in reality and in hypothetical choice experiments. In both cases, we found no robust evidence that drivers behave as if they misperceive travel times to a similar extent as those they misreported, thereby implying that the reported travel times did not represent the actual or perceived travel times in a truthful manner. The results of this study suggest that caution should be recommended when reported travel time data are used in an uncritical manner during transport research and when determining policy.     

反应舵在螺旋桨尾流中的水动力性能

本文对反应舵在螺旋桨尾流中的水动力性能及桨舵干扰进行了研究。舵的水动力及周围流场用面元法计算，螺旋桨性能用无限叶数的简易螺旋桨理论预估。桨舵干扰作用以迭代方法求得。采用面元法计算反应舵的性能，可以更精确地反映较复杂的反应舵表面形状对水动力性能的影响。通过计算得到的舵表面压力分布可看出反应舵节能的原因。本文还对反应舵的操纵性能进行了计算和研讨。     

汽车仪表板机器视觉检测技术

提出了用机器视觉系统对汽车仪表板总成进行智能检测的方法。仪表板质量检测的关键技术是提取边缘数据和定义指示误差。为有效地去除噪声并进行边缘数据提取，采用了小波变换模极大值的方法提取仪表图象特征，同时提出一种新的旨示精度评判准则。在此基础上，成功地研制出一种机器视觉检测系统。     

机械稳定土桥台整体变形观测结果分析

介绍了沈山铁路K273+555高架桥西立交桥20#加筋土桥台整体变形观测方法、过程、结果,以及对观测结果的最终分析。     

The impacts of Internet use upon activity participation and travel: Results from a longitudinal diary-based panel study

At the outset of this research, two fields of transport research were in the ascendant. The first reflected technological change, considering the growth of new information and communications technologies and their impacts for transport systems and travel behaviour. The second reflected social change, considering the growth in inequality and disadvantage and the contribution of transport systems and travel behaviour to the same. This paper investigates a potential link between the two, exploring the hypothesis that virtual mobility, via the Internet, could provide a viable alternative to physical mobility in reducing mobility-related social exclusion. The paper presents data from a longitudinal, panel-based diary study. Results support the hypothesis that virtual mobility can provide a viable alternative to physical mobility in reducing aspects of mobility-related exclusion, by providing additional accessibility (virtual accessibility) without an increase in physical mobility. Furthermore, there is no evidence in this research to support a link between physical mobility and virtual mobility; and no evidence to suggest a negative effect of virtual mobility for sociability.     

Global carbon dioxide emissions scenarios for aviation derived from IPCC storylines: A meta-analysis

This research summarises the aviation CO₂ emissions studies that use the Intergovernmental Panel on Climate Change IS92 and Special Report on Emissions Scenarios storylines as GDP growth assumptions to estimate future global carbon dioxide emissions from the aviation sector. The inter-quartile mean and the first and third quartiles are calculated to enable researches studying climate change policies for aviation to use an average global baseline scenario with lower and upper boundaries. We also perform a simple meta-analysis to analyse the assumptions used to derive the baseline scenario and conclude, as expected, that change in revenue-tonne-kilometres and fuel-efficiency are the main drivers behind the baseline scenarios.     

汽车覆盖件逆向设计方法

针对汽车覆盖件的特点,以某轻型货车前围覆盖件设计为例,提出一体化逆向设计思想。即由照相式扫描仪Camega得到数据点,采用Cloudprocess软件平台进行点云预处理,最后由逆向工程软件Imageware完成曲面重构。详细地阐述了如何由大量数据点进行曲线、曲面反求的汽车覆盖件逆向设计方法,并论证了该方法的可行性。     

车身板件振动声学贡献的计算机模拟

本文讨论车身板件振动声学贡献的计算机模拟研究方法。以桑塔那２０００型轿车为实例建立无吸声材料和吸声材料的结构－声学模型，使用ＡＮＳＹＳ有限元分析软件计算车身板件在给定频率下振动引起的车内声压，进而求得板件的声学贡献。