Flexible feeder transit route design to enhance service accessibility in urban area

To improve the accessibility of transit system in urban areas, this paper presents a flexible feeder transit routing model that can serve irregular‐shaped networks. By integrating the cost efficiency of fixed‐route transit system and the flexibility of demand responsive transit system, the proposed model is capable of letting operating feeder busses temporarily deviate from their current route so as to serve the reported demand locations. With an objective of minimizing total bus travel time, a new operational mode is then proposed to allow busses to serve passengers on both street sides. In addition, when multiple feeder busses are operating in the target service area, the proposed model can provide an optimal plan to locate the nearest one to response to the demands. A three‐stage solution algorithm is also developed to yield meta‐optimal solutions to the problem in a reasonable amount of time by transforming the problem into a traveling salesman problem. Numerical studies have demonstrated the effectiveness of the proposed model as well as the heuristic solution approach. Copyright © 2015 John Wiley & Sons, Ltd.     

澜沧江特大桥钢管拱二次竖转的计算与分析

以大瑞线澜沧江特大桥为例,选取梁单元模拟主拱,对拱肋二次竖转施工过程进行模拟,对结构进行计算及分析,给出了计算结果及总体评价意见。     

危险品装载符合证明的有效期问题

危险品装载符合证明(Form CFD)是一份证明文件,它是设备安全证书的一个附件,并非像有的人认为的那样是一份证书. 有些同志在FC中建议将CFD的有效期给到5年.原因一是认为CFD是一份证书,应按证书的要求执行,与船级的检验协调起来;二是知道它是设备安全证书的附件,认为应与SE证书的有效期一致.本人认为后一种想法在一定程度上是合理的,但在具体的操作上并不完善,存在管理上的漏洞.     

SBR法在天津港污水处理中心化学污水处理工程中的应用

介绍天津港化学污水处理工程的污水水源、水质及为实现处理方案而作的试验室试验情况，最后采用SBR法处理化学污水，主要指标达到国家三废排放标准。     

一种平行相交深孔加工新工艺的研究

针对平行相交孔难加工的工艺特点,提出一种径向力分段平衡的钻尖轮廓形式,并用于扳体零件的加工,取得了良好效果.此方法对该类工艺问题具有普遍意义.     

浅谈地铁车辆段洗车线接口

车辆段洗车线接口适用于计算机联锁车站和洗车线之间的联系。按照洗车线长度是否满足一列列车车长的要求,分别对车辆段洗车线接口进行了分析,从而保证洗车作业的安全和正常运营。     

城市轨道交通钢轨表面在线整修技术的应用分析

在调研城市轨道交通典型钢轨表面伤损的基础上,对比了在线钢轨整修技术的类型、优缺点和适应范围,并通过现场观测,分析了在线钢轨铣磨的效果。结果表明:在线铣磨可以很好地消除钢轨顶面、轨距角处的表面伤损,并恢复较高精度的标准轨头轮廓,公差为-0.1～+0.2 mm;在线铣磨提高了钢轨表面的整体纵向平顺度,各波长范围内不平顺幅值均方根降低50%以上,峰值超限数量降低40%～80%;焊接接头不平顺的恢复受铣磨量和不平顺原始幅值的影响。     

大跨度小净距隧道的数值模拟研究

以二广高速公路怀集至三水段西岸隧道为例，采用ANSYS有限元分析软件对洞口段开挖过程进行了模拟．获得了先挖隧道的位移、应力的分布规律及须采用的加固措施。     

铁路工程地质钻机的现状及发展方向

铁路工程地质钻探用钻机结构性能几十年未变,已远远不能适应目前钻掘工程和岩土工程的市场要求,通过对国内外钻机生产现状的分析,探讨铁路钻探设备的发展方向。     

Galling failure analysis in sheet metal forming process

Galling is a known failure mechanism in sheet metal forming operations,and it can lead to fracture of the products and jamming of the tool. The temperature field and normal contact pressure distributions of the tool and the blank were studied with a finite element analysis model under the action of different blank holder force and frictional coefficient. A series of forming tests of the high strength steel were conducted to validate the finite element model. The characteristics of galling failure,the damage...