Consumer preferences for battery electric vehicles: A choice experimental survey in China

To accelerate the diffusion of battery electric vehicles (BEVs), consumer preferences for different products and policy attributes must be determined. Although previous studies have investigated consumer preferences for some product attributes, including purchase price, operation cost, driving range, and charging time, limited studies have discussed the broader aspects of product attributes, such as battery warranty and depreciation rate. Moreover, market-oriented incentives, including the personal carbon trading (PCT) scheme and the tradable driving credits (TDC) scheme, can theoretically be effective alternatives to expensive purchase subsidies. However, there is a lack of empirical evidence that confirms the influence of these two schemes on BEV adoption. To fill these gaps, we conducted a stated preference choice experimental survey in China and investigated the effect of product attributes, existing policy incentives, and two emerging market-oriented incentives on BEV adoption. Our results reveal that along with the main product attributes, battery warranty has a significant positive effect on inducing mainstream consumers to adopt BEVs while no preference difference occurs among existing policy incentives after purchase subsidies are abolished. For young consumers, almost all incentives that reduce the operation cost (e.g., PCT) or increase convenience (e.g., TDC) can increase their adoption of BEVs. These findings can provide important implications for the government with regard to designing novel incentives and promoting BEV adoption.     

Using on-board logging devices to study the longer-term impact of an eco-driving course

In this paper the long-term impact of an eco-driving training course is evaluated by monitoring driving behavior and fuel consumption for several months before and after the course. Cars were equipped with an on-board logging device that records the position and speed of the vehicle using GPS tracking as well as real time as electronic engine data extracted from the controller area network. The data includes mileage, number of revolutions per minute, position of the accelerator pedal, and instantaneous fuel consumption. It was gathered over a period of 10 months for 10 drivers during real-life conditions thus enabling an individual drive style analysis. The average fuel consumption four months after the course fell by 5.8%. Most drivers showed an immediate improvement in fuel consumption that was stable over time, but some tended to fall back into their original driving habits.     

管线敷设与风机室布置对综合管廊通风阻力影响研究

为准确估算管线敷设与风机室内气流相互作用对压降损失的影响,基于武汉市江夏区谭鑫培路地下综合管廊项目建立典型数值分析模型与分析流程。通过建立典型管线布置的GIL舱、高压舱与综合舱的计算流体动力学三维模型,分别对入口段与稳定段进行分析,并使用循环边界条件来考虑稳定段流体的充分发展,得到阻力系数随流量的变化规律;通过建立GIL舱典型排风口三维模型,分析风机室中不同风机的压降损失,并与规范估算值进行比较。研究结果表明： 管线敷设对压降损失的影响不可忽视;风机室风机相互作用显著,规范不能准确估算该相互作用导致的压降损失。     

Back-Calculation of Ground Stress Field and Rockburst Analysis for Wunvfeng Tunnel北大核心CSCD

Studying the in-situ stress distribution at a tunnel site is very important to determine surrounding rock characteristics, the engineering design and the construction scheme. By using the multiple linear regression method based on the least square algorithm, the initial geostress field is analyzed and the corresponding regression coefficients are obtained. The ground stress obtained from the proposed back analysis is reasonable and can meet the demands of the engineering applications. From the rockburst risk level distribution diagram, it is speculated that the Wunvfeng tunnel is in the high filed stress area. Field monitoring should be strengthened and emergency plans should be made to cope with the rockburst risks during the construction process. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

大丰港海域挟沙力关系式分析及应用

基于大丰港附近海域实测水文泥沙资料,对目前国内应用较为广泛的5种挟沙力关系式在大丰港附近海域进行应用计算,在此基础上,采用集中系数法和偏离系数法对计算结果进行对比分析。结果表明:河口水流挟沙力公式能较好地反映大丰港海域的水流挟沙情况,并拟合得到适用于大丰港海域的挟沙力关系式,将该公式应用于大丰港实际围垦工程中,通过建立二维水动力泥沙数学模型,计算得到的围垦后垦区海域年冲淤变化趋势,与数值模拟结果基本相同,表明该公式在大丰港海域具有良好的适用性。     

单向和多向不规则波作用下港域波浪数值研究

采用MIKE-BW模型对TEMA港内波浪场进行数值模拟和验证,二者吻合良好。在此基础上对比分析单向和多向不规则波作用下港内波浪条件,以及随入射波向和谱峰周期的变化规律。结果表明:在以绕射为主的模型中,多向波扰动系数大于单向波,此时采用多向波更加安全合理,并且在模型计算中,不可忽视地形变化对港域波高分布的影响;在模型边界反射较强的模型中,单向波扰动系数可能大于多向波扰动系数,此时采用单向波会更加安全。     

波浪作用下斜坡式护岸反射系数试验

通过物理模型试验,研究在不规则波作用下,斜坡坡度、波陡、扭王字块体的摆放方式对反射系数的影响,并将实测的反射系数与Seeling公式、Sutherland公式和Van der Meer公式的计算值进行比较。结果表明斜坡坡度与反射系数成正比,波陡与反射系数成反比,扭王字块体的摆放方式对反射系数的影响不大,试验值普遍比3种公式的计算值要大,其中试验值与Seeling公式的计算值相差较小。     

桩-土-承台相互作用的有限元简化模型

针对低桩承台结构计算中往往只考虑桩土作用,忽视承台与土相互作用的问题,通过工程实例,建立考虑桩-土-承台相互作用的低桩承台有限元简化模型,分析桩间土的承载作用对承台和桩内力的影响。结果表明:在简化模型中考虑桩间土的承载作用后,承台弯矩和桩基轴力可减少35%～40%;桩身弯矩和剪力主要受水平力和土体m值影响;桩基轴力随地基土基床系数的增大而逐渐减小,但减幅逐渐趋缓。     

钢板桩常规施工工艺及涂层受损问题

针对钢板桩施工问题,以马来西亚槟城吹填二期(STP2)工程为例,对Z型钢板沉桩机具选型及沉桩工艺进行研究。通过对比3种国外常用的钢板桩沉桩阻力估算方法及含导向架和无导向架施工的实际应用效果,优选出适合沉桩的振动锤型,并总结出两种沉桩方法的优劣性及适用情况,总结陆上钢板桩作业涂层常见受损问题及修复措施。     

双月池对某援潜救生船运动性能及波面升高的影响

介绍某援潜救生船配设双月池的船型特点,规划双月池和不带月池2种方案来评估双月池开口对援潜救生船船体运动性能的影响。采用三维势流理论对2个方案的运动性能进行计算,得到船体运动响应函数,对船舶运动性能进行短期预报,研究总结双月池效应对援潜救生船运动的影响规律。对比双月池内水面和舷外波面升高的情况,比较两个位置处波面升高的差异性,总结双月池波面升高对潜水钟收放的影响。