Mapping commuter cycling risk in urban areas

Cycling is becoming an increasingly important transportation option for commuters. Cycling offers exercise opportunities and reduces the burden of motor vehicle travel on society. Mapping the risk of collision between cyclists and motor vehicles in urban areas is important to understanding safe cyclist route opportunities, making informed transportation planning decisions, and exploring patterns of injury epidemiology. To date, many geographic analyses and representations of cyclist risk have not taken the concept of exposure into account. Instead, risk is either expressed as a rate per capita, or as a count of events. Using data associated with the City of Hamilton, Canada, we illustrate a method for mapping commuter cyclist collision risk per distance travelled. This measure can be used to more realistically represent the underlying geography of cycling risk, and provide more geographically and empirically meaningful information to those interested in understanding how cycling safety varies over space.     

城市群快速轨道客运系统建设策略分析

城市群空间的形成要求借助于区域或城市间的完善的交通网络体系,许多城市群建立以大容量的快速轨道客运系统为骨干,地面辅以常规多类型公共交通网络为补充的多层次、多元化、立体化的客运交通方式相互协调的综合客运交通体系,并以此城市群综合客运交通体系为城市交通发展的基本战略。本文在此主要研究我国城市群快速轨道交通规划中的建设策略。     

江西经济发展走势对运输需求的分析与预测

区域经济的发展是运输需求的源泉。新世纪以来,江西经济进入了持续稳定发展的快车道,极大地促进了运输需求的持续增长,运输线路长度不断延长,全社会运输量不断增加。随着江西经济社会快速发展,城镇化进程的加快,资源环境约束压力的加大,运输需求结构提升,对运输需求提出了更高的要求,运输需求多样化、个性化、机动化、快速化和网络化的趋势更加显著。     

模糊蚁群优化算法在交通导航系统中的应用

为了能处理交通导航系统中的模糊信息,并且能快速的综合多种信息求解最优导航路径,将模糊逻辑推理技术与改进的蚁群算法相结合提出了一种新的算法——模糊蚁群混合优化算法。实验表明,该算法不仅能够处理导航系统中的各种模糊信息,并且能利用改进的蚁群算法快速求解最优导航路径。     

习家口油田集输系统清洁生产工艺改造

习家口油田单井管线腐蚀严重,经常发生管线穿口事故。由于伴生气量少,翻斗计量工艺无法运行。针对这种情况采用流量计计井口计量和树杖状串联常温集输工艺,降低了能耗,避免了运输油过程中的烃类气体的排放,减少了环境污染。据统计,习家口油田年减少烃类气体挥发100万方左右,生产运行费用大幅降低,取得了较好的经济效益。     

液化天然气储罐翻滚事故分析

随着世界能源紧缺现状的出现,天然气工业在我国的不断发展,液化天然气成为了一种成效卓著的储运方式,那么,随乊而来的便是液化天然气的安全问题,分层、翻滚是液化天然气在储存过程中有可能出现的一种极其危险的事故现象。通过FLUENT模拟软件对LNG储罐中不同物性参数的液化天然气在罐体漏热情况下进行数值模拟,在此乊前通过计算对大型LNG储罐漏热进行求解,将计算得到的热流密度近似取成10W/m2,以此作为模拟时边界条件的罐壁、罐底漏热量,模拟得出翻滚发生的开始和结束时间,最后通过翻滚发生持续时间计算仅翻滚时所造成的LNG损失,约334 t,翻滚发生前,储罐内的气相空间压力梯度约为32 kPa/h,仅约20 min便会使储罐内正常操作压力超出安全阀设定压力。由此可见,液化天然气翻滚事故的发生不仅会造成液化天然气本身的一大浪费,同时也会对人身及财产安全构成巨大威胁,因此,深入研究LNG翻滚对社会发展具有深远意义。     

油气集输课程建设探讨

油气集输是石油储运工程专业本科生的一门专业必修课。进入21世纪,原油战略储备、西气东输、陆上进口天然气和海上进口LNG的一系列重大工程的实施,为油气集输提供了广阔的舞台。为了培养学生的创新能力,办出华东理工大学油气储运专业的特色,近年来我系进行了油气集输课程建设的教学与实践,力求培养出基础知识宽厚、工程能力较强的油气储运工程高层次人才。     

啮合同向双螺杆挤出机单／双头螺纹元件熔体输送与混合特性的研究

采用数值模拟和实验的方法,对啮合同向双螺杆挤出机中单／双头螺纹元件的熔体输送与混合特性进行对比。结果表明,在计量输送段放置一段单头螺纹元件时,回流量小,正向输送能力强;螺杆所受扭矩小,消耗能量少;挤出物料的耐冲击性能较高。     

孟加拉国凝析油处理厂总图设计分析

通过对孟加拉国凝析油处理厂项目在总图运输设计当中的特点,分析了场地的布局设计、平面竖向分析,叙述了主要工程做法,当地气候对设计产生影响,今后如何提高对外项目设计水平。     

The engineering rheology of liquid explosives as highly concentrated emulsions

Rheological properties of liquid explosives are summarized and discussed in this paper. Liquid explosives are highly concentrated emulsions by their physical nature. During the internal phase, it is an aqueous supersaturated solution of mainly ammonium nitrate which is a useful component of a multi-component system, and at the continuous phase it is a solution of emulsifier in hydrocarbon oils. Liquid explosives demonstrate a complex set of properties characteristic for highly concentrated emulsions, such as visco-plasticity, existence of the yield stress, thixotropy (or time-dependent behavior), non-Newtonian flow at stresses exceeding the yield stress. Rheological properties depend on the concentration of internal phase, size of droplets, and the nature of the used surfactant. Stability of these materials is determined mainly by the tendency of an aqueous solution to crystallization at prolonged storage, though shearing does not influence on phase separation. Wall slip is absent in flow of liquid emulsions through tubes. Therefore, it allows us to make reliable predictions on the output vs. pressure dependence for real technological practice.