Fault tree analysis of fire and explosion accidents for dual fuel (diesel/natural gas) ship engine rooms

In recent years, China’s increased interest in environmental protection has led to a promotion of energy-efficient dual fuel (diesel/natural gas) ships in Chinese inland rivers. A natural gas as ship fuel may pose dangers of fire and explosion if a gas leak occurs. If explosions or fires occur in the engine rooms of a ship, heavy damage and losses will be incurred. In this paper, a fault tree model is presented that considers both fires and explosions in a dual fuel ship; in this model, dual fuel engine rooms are the top events. All the basic events along with the minimum cut sets are obtained through the analysis. The primary factors that affect accidents involving fires and explosions are determined by calculating the degree of structure importance of the basic events. According to these results, corresponding measures are proposed to ensure and improve the safety and reliability of Chinese inland dual fuel ships.     

基于最小二乘支持向量机的地铁弓网系统研究与仿真

提出了一种基于误差相关性的弓网系统模型,采用最小二乘支持向量机(LSSVM)方法对模型的参数进行研究探讨,并对误差相关性系数进行分析,最后利用既有线的弓网实际检测试验数据对弓网接触压力值进行仿真分析。结果表明:基于最小二乘支持向量机的弓网模型能够描述接触压力的动力学行为,具有较高的预报精度。     

超浅埋盾构法隧道施工方案三维有限元分析

文章以某水库流域污水通道盾构法隧道施工方案为工程背景,运用MARC大型三维有限元分析系统,对该超浅埋盾构法施工方案进行了三维有限元模拟,分析了不同工况下盾构衬砌和锚杆的受力及变形,并计算出了盾构衬砌的纵向接缝张开量及锚杆轴力.     

High-Speed Rail Operations on an Existing Network: An Assessment Model for China

High-speed rail operations have the potential to reduce the long-term decline in rail passenger travel demand for the medium to long distance inter-urban markets. Such decline has been evident through most of the industrialized countries where air and road transport tend to be the dominant modes. In China, the operations of long distance high-speed rail on fully dedicated track is not very easy to implement, due to the high proportion of passengers who travel between high-speed and conventional railways. An alternative approach would be to allow for mixed operations with trains of various speeds on the same track. This article puts forward a simulation model designed to allow an evaluation of the most efficient distance for high-speed rail operations under mixed train speed scenarios. The model takes into account the main operating parameters such as passenger volumes, train speeds, capital and maintenance costs, train operating costs and energy consumption. The distance of high-speed train running on conventional rail that will yield the most economic benefit can be estimated using the model. The article includes the results of using the model for a specific example. It is concluded that large-scale high-speed trains have the potential to be successfully operated on conventional rail networks.     

复合地层中盾构滚刀磨损原因分析及对策

通过系统地总结和分析约40台次混合式盾构机在复合地层中掘进近100 km的滚刀磨损情况,对滚刀磨损做了定性分类,并根据滚刀磨损的影响因素,提出滚刀磨损的对策,以期指导今后复合地层施工中盾构机刀盘刀具选择、配置及盾构掘进。     

白车身刚度试验与仿真分析研究

在刚度试验台上对某MPV白车身进行弯曲和扭转刚度试验,并与有限元分析结果进行对比,其结果表明:扭转刚度对比误差为7.56％,弯曲刚度对比误差为1.85％,仿真精度满足要求,可以为进一步的结构分析优化提供基础.     

地铁车站建筑形态的自明性与差异性

从地铁车站建筑的特性出发,结合目前国内地铁车站建筑现状,分析车站建筑形态的自明性表现,总结分析营造车站建筑的差异性的三种典型处理手法,探讨以可持续设计观念来实现车站建筑技术与人文精神的结合。     

移动支架造桥机一次架设两孔施工技术研究

随着铁路事业的大发展,工程施工的机械化、工厂化、专业化、信息化已经成为国际发展趋势,标准化的建设将有助于施工产品的质量、外观等综合效益的进一步提高,而节段拼装其独有的优势也将得到大力发展。由于工序的影响,单孔的架设速度已很难提高,所以一次架设两孔,形成2个作业面,无疑将是提高效率的一个方向。对节段拼装法一次架设两孔的造桥机结构和施工技术进行了研究,将为今后类似项目的实施提供一定的参考。     

空压机余热利用及节能效益分析

空压机余热回收是指一项新型高效的余热利用回收技术,依靠吸收空压机运行时产生的废热使水加热,再将加热的水用于员工的生活、工业用所需,没有太大的能源消耗。作为一种新型高效的余热利用技术,可以为企业节省能源的消耗,从而节省大量的成本。     

基于IDM的需求扰动供应链协调契约研究

针对具有需求扰动风险的供应链协调问题,基于利益驱动机制,设计出一种新的保险契约模式,建立相应的供应链模型并求解分析。结果表明：均匀分布市场需求下赔偿上限应足够大,且契约参数满足相关条件时供应链可以达到完美协调。最后通过数值分析了赔偿参数对订货量和保费的影响。