Why are maritime ports (still) urban,and why should policy-makers care?

Despite ongoing transformations in the maritime transportation industry and the rise of global supply chain systems, most of the world's important container ports remain urban. Ports continue to occupy urban spaces, are embedded in localized knowledge systems, draw on urban labour markets and infrastructure and are subject to local politics and policy concerns. We identify contemporary geographic theories which help us understand the often increasingly urban attachment of core economic activities despite globalization. We explore how these theories may apply to port studies, highlighting both how they have been used by maritime scholars to this point and also why further development and application are warranted. We argue that a central concern of these geographic theories is the articulation of place- and sector-specific processes operating at a variety of spatial scales. This is in contrast to most maritime studies which continue to be dominated by perspectives which emphasize the global logic of the transportation industry and the analysis of space in generalized and abstract terms. We conclude that a re-appreciation in maritime studies of urban economic processes, informed by geographical theory, will provide policy-makers and others with more understanding of why deep connections between ports and urban places still matter.     

双向与单向道路网络:哪一个更高效?

为了改善机动车的可达性并避免驾驶人迷失,城市政府和规划师开始将中心城区传统的单向道路网络转换成双向行驶。双向道路网络可提升经济活力水平和中心城区的宜居性,而单向道路网络可提高通行能力。指出使用出行服务能力指标来衡量道路网络效率更适宜,将单向行驶与双向行驶道路网络的出行服务能力进行对比,后者交叉口的处理包括左转专用车道、左转渠化和禁止左转三种方式。结果显示,与传统认知和设计手册相反,双向道路网络通常比单向道路网络更有效率。在出行距离较短的情况下,允许转向的双向道路网络比单向道路网络的出行服务能力更高;禁止左转的双向道路网络比单向道路网络造成的绕行更少。     

Simulation of longitudinal dynamics of a freight train operating through a car dumper

A heavy haul train and car dumper model was created to analyse train longitudinal dynamics during dumping. Influence of such factors as performance curve of draft gears, total free slack in couplers, operating mode of train positioner and braking of last two cars of train on the in-train forces was considered.