Well-to-wheel assessment of natural gas vehicles and their fuel supply infrastructures – Perspectives on gas in transport in Denmark

In this paper, potential natural gas and renewable natural gas supply pathways and natural gas vehicles (NGVs) have been selected and evaluated with regards to well-to-wheel energy expended, greenhouse gas (GHG) emissions, and regulated (air pollutant) emissions. The vehicles included in the evaluation are passenger cars, light-duty vehicles (LDVs), and heavy-duty vehicles (HDVs) for road-transport applications, and a short-range passenger vessel for maritime transport applications. The results show that, compared to conventional fuels, in both transport applications and for all vehicle classes, the use of compressed and liquefied natural gas has a 15–27% GHG emissions reduction effect per km travel. The effect becomes large, 81–211%, when compressed and liquefied renewable natural gas are used instead. The results are sensitive to the type and source of feedstock used, the type of vehicle engine, assumed methane leakage and methane slip, and the allocated energy and environmental digestate credits, in each pathway. In maritime applications, the use of liquefied natural gas and renewable natural gas instead of low sulfur marine fuels results in a 60–100% SOx and 90–96% PM emissions reduction. A 1% methane slip from a dedicated LNG passenger vessel results, on average, in 8.5% increase in net GHG emissions.     

Platoon based cooperative driving model with consideration of realistic inter-vehicle communication

Recent developments of information and communication technologies (ICT) have enabled vehicles to timely communicate with each other through wireless technologies, which will form future (intelligent) traffic systems (ITS) consisting of so-called connected vehicles. Cooperative driving with the connected vehicles is regarded as a promising driving pattern to significantly improve transportation efficiency and traffic safety. Nevertheless, unreliable vehicular communications also introduce packet loss and transmission delay when vehicular kinetic information or control commands are disseminated among vehicles, which brings more challenges in the system modeling and optimization. Currently, no data has been yet available for the calibration and validation of a model for ITS, and most research has been only conducted for a theoretical point of view. Along this line, this paper focuses on the (theoretical) development of a more general (microscopic) traffic model which enables the cooperative driving behavior via a so-called inter-vehicle communication (IVC). To this end, we design a consensus-based controller for the cooperative driving system (CDS) considering (intelligent) traffic flow that consists of many platoons moving together. More specifically, the IEEE 802.11p, the de facto vehicular networking standard required to support ITS applications, is selected as the IVC protocols of the CDS, in order to investigate how the vehicular communications affect the features of intelligent traffic flow. This study essentially explores the relationship between IVC and cooperative driving, which can be exploited as the reference for the CDS optimization and design.     

自动闭塞设计的新理念

CTCS 技术规范的制定,对自动闭塞设计的传统理念和方法产生了冲击,探讨采用目标距离模式曲线方式控车后的自动闭塞的设计原则和方法,建议采用闭塞分区等长设计。     

区域计算机联锁站间安全通信的实现

阐述了区域联锁站间通信的技术要求，该通信使用的传输设备、传输媒介、通信协议、安全通信网络的拓扑结构等，描述了安全通信在实际区域联锁中的应用。     

船舶安全管理决策的多目标信息效用模型研究

根据船舶安全管理决策的复杂性,运用多目标效用理论,构建了船舶安全管理决策的多目标信息效用模型,并以船舶适航性和经济效益为目标,对所建立的模型进行验证,表明其科学性和合理性。该模型的建立对于理顺安全管理决策多目标之间的关系,实现船舶安全管理决策的科学化,具有十分重要的现实意义。     

国产道岔除雪系统发展方向

通过对铁路道岔加热融雪系统的深入调研,阐述了国产道岔融雪系统的选型、安全使用及发展方向。     

企业专用铁路安全管理的问题与对策

根据企业专用铁路的特点,针对生产运营中存在的员工业务素质有待提高、设备状况有待改善、运输安全基础薄弱、外部环境有待改善等问题,提出抓住关键,规范安全基础管理；着眼根本,强化人力资源开发；加大投入,改善设备技术状况；多管齐下,营造良好运营环境等构建专用铁路安全的长效机制,实现企业安全发展的对策.     

柴油机活塞的低周热疲劳寿命预测与安全性评价

运用ＡＤＩＮＡＴ和ＡＤＩＮＡ程序计算了１２Ｖ１８０和４２－１６０柴油机活塞的轴对称温度场和循环弹塑性应力应变场以及Ｍｉｓｅｓ当量应力应变场。根据“起动－停车”波形，采用带环状缺口的圆柱形试件，进行了热疲劳和高温低周疲劳模拟试验试验和计算表明：当量应变范围与疲劳寿命之间存在着Ｍａｎｓｏｎ－Ｃｏｆｆｉｎ公式关系，且不受试件结构形状和尺寸的影响；     

5T系统整合中基于模型驱动的Web服务组合方法研究

针对5T系统整合流程复杂、多变的特点,提出基于模型驱动的Web服务组合方法。该方法采用面向服务的架构,通过Web服务的组合实现对5T系统的整合。在Web服务组合过程中,以建模代替编码,建立模型到代码的映射机制,实现代码的自动生成。给出对Web服务组合模型的描述规则,并通过将平台相关模型由UML格式文档转换成XML格式文档、再转换成代码的方法,实现代码映射。以5T系统踏面擦伤报警评判及维修指导流程为例,建立了5T系统报警评判和故障处理的流程模型。实例表明:该方法可有效降低5T系统整合的复杂性,提高系统的适应性以及跨平台互操作能力。     

浅析油品运输中"转换装油"引起的安全问题

从一起油轮爆炸事故，分析了事故的起因主要是由于“转换装油”引发的。后经随机调查发现，现阶段油轮“转换装油”现象非常突出。针对此现象，客观分析了油轮“转换装油”危害性及引发事故的原因，并提出了有效的防范措施，呼吁广大从业人员一定要加强防范意识。