能耗吸收装置在城市轨道交通系统中的应用

介绍了城市轨道交通系统能耗吸收装置的原理和组成,分析了能耗吸收装置的能量吸收过程和系统控制方式,总结了能耗吸收装置运用过程中的故障种类、故障现象及相应的故障解决方法。     

电动汽车充电桩安全管理研究

随着国家对环境保护和能源节约的重视以及新能源政策的实施,电动汽车行业迎来了快速发展。充电基础设施的建设,是加快电动汽车推广的重要需要。电动汽车充电基础设施建设和运营业务发展的机会也极大,随之而来的安全管理工作要求也越来越高。本文依据充电桩建设和运营的特点,剖析其中面临的安全风险,并提出加强安全管理工作的措施,为充电桩企业安全管理运营提供参考和借鉴。     

热扰动对冻土区片块石路基热状态变化特性的影响研究

随着我国现阶段的公路建设里程不断增长,相较于常规平原地区,高寒冻土区公路建设过程要克服冻土路基带来的各类不良影响.针对热扰动对冻土区片块石路基带来的影响进行深入研究,在分析该区域高等级公路路基状态的过程中,采集片块石路基的温度状态、吸放热状态和冻融循环状态等方面数据,探讨了其热状态变化的整体规律.研究结果显示:片块石路...     

基于云平台的城市轨道交通能源管理系统

阐述了基于云平台的城市轨道交通能源管理系统架构和建设方式.该系统利用云计算的高效和弹性来部署建设,采用线网-车站二层管理模式,降低了线网和线路服务器等的硬件部署成本和维护成本.通过将能源管理系统内部使用的业务应用转换为基于云平台的能源管理应用软件,能源管理系统可获取云平台提供的共享数据,并将经过业务处理后的数据存储到云...     

自航耙装舱装置消能效果比较试验

通过物理模型试验模拟自航耙吸挖泥船装舱溢流施工过程,以舱内流速、舱内浓度、溢流进出口泥沙粒径、装舱量几方面为主要控制因素,进行实测、分析,并比较自航耙4种常用装舱装置的消能效果。试验结果表明各种装舱装置的优劣效果差距并不明显,仿新海龙型装舱装置效果略好。     

多芯管套料工艺改进

为解决船用多芯管套料存在的材料利用率低、现场剩余材料浪费突出的问题,对多芯管的建模流程、采购流程和套料流程进行管控,形成新的更加合理有效的多芯管套料工艺,采用新工艺可达到最大限度提升多芯管套料合理性,提高材料利用率,减轻设计人员工作负荷,降低采购成本的目的.     

超声相控阵缺陷检测技术研究

为了将相控阵超声检测技术进一步推广应用,对带有人工缺陷的试件分别采用CR、超声相控阵检测技术进行检测,将检测结果进行比对,试验结果表明CR检测技术与相控阵检测技术在体积型缺陷与面积型缺陷检出率方面各具优势,应结合实际工件使用工况,确定可能出现的缺陷类型,采用合适的检测方法与检测工艺,最大限度地提高缺陷检出率.     

沿程磁处理管道输油实验研究

南海原油密度大、含蜡量高,对南海原油采用沿程磁处理,可降低聚集度,从而达到降黏输送的作用.为进一步研究磁处理对油品有降黏效果,使用仿真软件模拟磁铁摆放得到磁感应强度分布,再通过搭建沿程磁处理输油实验管道,以南海原油为介质进行实验研究.将有无磁处理的压力数据进行对比,并结合使用流变仪测定的油品黏度变化,综合分析得出使用2...     

Effects of countdown timers on queue discharge characteristics of through movement at a signalized intersection

This study investigates how countdown timers installed at a signalized intersection affect the queue discharge characteristics of through movement during the green phase. Since the countdown timers display the time remaining (in seconds) until the onset of the green phase, drivers waiting in the queue at the intersection are aware of the upcoming phase change, and are likely to respond quicker. Thus, the countdown timers could reduce the start-up lost time, decrease the saturation headway, and increase the saturation flow rate. This study observed vehicle flow at an intersection in Bangkok for 24 h when the countdown timers were operating, and for another 24 h when the countdown timers were switched off. The signal plans and timings remained unchanged in both cases. Standard statistical t-tests were used to compare the difference in traffic characteristics between the “with timer” and “without timer” cases. It was found that the countdown timers had a significant impact on the start-up lost time, reducing it by 1.00–1.92 s per cycle, or a 17–32% time saving. However, the effects on saturation headway were found to be trivial, which implies that the countdown timers do not have much impact on the saturation flow rate of signalized intersections, especially during the off-peak day period and the late night period. The savings in the start-up lost time from the countdown timers was estimated to be equivalent to an 8–24 vehicles/h increase for each through movement lane at the intersection being studied.     

Weight threshold estimation of falling UAVs (Unmanned Aerial Vehicles) based on impact energy

Different weight thresholds for drone operations have been specified by regulatory agencies in different countries, without detailed backgrounds of guidelines. Therefore, this paper aims to study weight thresholds by focusing different levels of injuries caused by the impact of the drones on human head of different weights dropped at various heights. The work covers drone free drop modelling, FEM (finite element method) based impact modeling, and comparable drop impact experiments. The analyses and experiments were conducted accordingly to two individual commercially-available groups: small and large drones in weights. Two well-established indicators defining head injuries due to impact, which are known as Head Injury Criterion (HIC) and Abbreviated Injury Scale (AIS), are used in the present weight threshold study. The proposed AIS level for the weight threshold estimation has been set at AIS level 3, which indicates major skull fracture, in the further analysis through the probability of fatality. The main focus of the present work is to perform a parametric study and to present a reliable model to estimate the weight thresholds of the drone operations based on HIC and AIS. In conclusion, the results obtained and presented in this paper have demonstrated and provided a comprehensive analysis of possible direct injuries of a falling drone impacting a human head, with relevant data of impact or injury levels associated with HIC and AIS obtained for a drone with different weights falling from various heights.