驾驶疲劳监测方法综述

随着国民经济的发展,汽车持有量的增加,交通事故也成为交通事业发展的一个严峻挑战。针对这些情况,车辆驾驶安全技术的研究取得了很大发展。文章从驾驶疲劳的研究现状、驾驶疲劳研究存在的问题等方面对驾驶疲劳监测方法进行了综述性研究,着重对基于机器视觉的驾驶疲劳监测方法进行了研究,为驾驶疲劳的检测技术的开展提供了参考。     

Assessing the energy and greenhouse gas emissions mitigation effectiveness of potential US modal freight policies

This paper estimates the total embodied energy and emissions modal freight requirements across the supply chain for each of over 400 sectors using Bureau of Transportation Statistics Commodity Flow Survey data and Bureau of Economic Analysis economic input-output tables for 2002. Across all sectors, direct domestic truck and rail transportation are similar in magnitude for embodied freight transportation of goods and services in terms of ton-km. However, the sectors differ significantly in energy consumption, greenhouse gas emissions, and costs per ton-km. Recent pressure to reduce energy consumption and emissions has motivated a search for more efficient freight mode choices. One solution would be to shift freight transportation away from modes that require more energy and emit more (e.g., truck) to modes that consume and emit less (e.g., rail and water).Our results show there are no individual sectors for which targeting changes would significantly decrease the total freight transportation energy and emissions, therefore we have also looked at the prospect of policies encouraging many sectors to shift modes. There are four scenarios analyzed: (1) shifting all truck to rail, shifting top 20% sector mode choice, (2) based on their emissions, (3) based on a multi-attribute analysis, and (4) increasing truck efficiency (e.g., mpg). Increasing truck efficiency by 10% results in similar energy and emissions reductions (approximately 7% for energy and 6% for emissions) as targeting the top 20% of sectors when selected based on emissions, whereas selecting the top 20% based on availability to shift from truck results in slightly less reductions of energy and emissions. Implementing policies to encourage higher efficiency in freight trucks may be a sufficient short term goal while efforts to reduce truck freight transportation through sectoral policies are implemented in the long term.     

Evaluating gravel transport sustainability: A case study of Taiwan’s northeast corridor

We use social-eco-efficient analysis in the form of SEEbalance to evaluate gravel transport sustainability for trucking and two kinds of intermodal transportation. Results show that switching from trucks to intermodal transportation can improve the sustainability of gravel transportation in the northeast corridor of Taiwan. Sensitivity analysis shows that rail combined with truck intermodal transportation has competitive advantage despite the terminal’s location factor.     

基于计算机模拟的轿车侧门防撞杆对美国侧撞法规作用的研究

FMVSS214是美国轿车侧向碰撞法规,它包含动态试验和准静态试验2方面的要求。基于LS-DY-NA计算机软件的模拟技术,研究了3种侧门防撞杆结构对某车型的FMVSS214性能的影响,并提出了适于该车型的侧门防撞杆优化设计方案。     

交流鼠笼式牵引电动机两种典型故障分析与改进措施

定子槽口接地和转子导条断裂是交流鼠笼式牵引电动机最常见的两种典型故障,文中对这两种故障进行了原因分析,并提出预防性措施:定子槽口灌封和导条打无纬带,应用了新的灌封材料和新的工艺结构,取得了良好效果.     

钢筋混凝土结构钢筋锈蚀模型及影响因素分析

在海洋环境下,钢筋混凝土构件的物理、力学特性随时间发生明显变化,使结构的安全度降低。影响钢筋混凝土构件耐久性的主要原因是钢筋锈蚀。关于钢筋锈蚀计算,有多种计算模型,不同计算模型的计算结果存在着较大差异,计算模型中相关参数的取值也有很多不同研究成果。本文通过算例,对各种模型及其相关参数的影响进行比较分析,可为钢筋混凝土结构耐久性设计和开展进一步研究工作提供参考。     

横隔梁拉压杆模拟配筋与实际设计对比分析

文章基于某特定桥梁的横隔梁设计状态,借助工程有限元ANSYS模拟计算系统,以横隔梁拉压杆模拟配筋与工程实际设计配筋两种配筋功效对比分析的方式,对横隔梁拉压杆模拟配筋课题开展专题分析探究,数据化揭示基于压拉杆模型配筋法的混凝土横隔梁载承力设计功效。     

铝棒导线在汽车线束领域的应用

由于混动汽车和纯电动汽车的逐步发展,铝棒导线正在逐渐被人们所熟知和应用。文章介绍铝棒导线的特点及应用,并对比铝棒导线与常规导线在生产工艺和焊接方式上的差别。归纳总结铝棒导线在设计使用过程中常见的问题及对策,对后续铝棒导线的设计和使用有一定的借鉴意义。     

隧道施工对邻近砌体结构影响的数值分析

隧道施工会引起周围土体移动。进而对邻近建筑物产生危害。建立隧道从砌体结构正下方和右下方穿越的三维有限元模型．分析地表在隧道开挖和既有砌体结构共同作用下的位移变化规律、砌体结构变形及损害程度。结果表明：砌体结构的自重会显著增大地表沉降值及其范围,其刚度会减小地表的差异沉降,门窗及拐角处由于应力集中发生较大剪应变,砌体的最大剪应变决定于相对位移。隧道从砌体右下方穿越引起的砌体损害程度较大。     

大型深水导管架建造工况条件下的杆件涡激振动评估

基于国内某深水导管架项目，从工程实用角度出发，介绍在导管架建造过程中杆件涡激振动的理论评估方法和约束条件的选择标准，并对结构片总装时的涡激振动进行计算。结果表明：较弱的约束条件使杆件更易发生涡激振动；不同规格杆件的涡激振动对约束条件的敏感性不同；高柔度杆件具有相对更高的涡激振动风险，短粗型杆件的涡激振动对约束状态的变化更敏感。