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The critical nature of a seaport is a connection point. In addition to the effect on port operations, a port disruption will be a strain on trade flows and the various parties concerned. Climate change, oil spill, security, social and political instability are increasing concerns over the years which would lead to higher risks. With significant growing trade volume in Asia, there is a pressing need for comprehensive studies to prepare ports for disruptions. This paper aims to analyse and categorise the disruptions that have occurred in Asian ports and estimate the likelihood of recurrence based on the data since the year 1900. Results reveal a rising trend of disruptive events. Natural disasters and labour strikes are the two main causes of port disruptions, while natural disasters lead to the highest severity in terms of cargo tons affected. Mitigation strategies proposed in terms of both preventive and reactive measures are specifically designed to reduce the likelihood and severity of the various types of port disruptions. The paper provides recommendations on risk mitigation for relevant parties. 相似文献
383.
Jin‐Su Mun 《运输评论》2013,33(2):231-249
Abstract This paper provides a review of the traffic performance models for dynamic traffic assignment (DTA) and it identifies the strength and weakness of existing models. Requirements for traffic performance models are identified and various forms of existing traffic performance models for DTA are reviewed and analysed according to the requirements. Non‐linear travel time models are shown to have some deficiencies that make them unsuitable for the analysis of time‐varying transportation networks. Even though linear‐type travel time models are identified as good candidates for the analysis of dynamic transportation networks, they have limitations from the practical point of view that travel time increases only linearly with the amount of traffic on the link. This poses a dilemma and it seems to be one whose resolution is an imminent precondition for DTA modelling to progress in a way that is both theoretically coherent and plausible in practical terms. 相似文献
384.
The microstructure and hardness of conventionally solidified Ni-xSi (x = 21.4%, 22%, 24%, 26%) alloys were investigated. The solidification microstructures of different Ni-Si alloys were observed by optical microscope (OM) and scanning electron microscope (SEM) and the phase composition was indentified under the help of energy dispersive X-ray (EDX) analysis. The macro- and micro-hardness of the Ni-Si alloys at room temperature were also examined. The experimental results indicated that both the microstructure and hardness closely depended on the Si content. Due to the vast formation of primary ??-Ni31Si12 phase, the hardness of Ni-26.0%Si alloy was significantly improved compared with that of Ni-21.4%Si eutectic alloy. However, the fracture toughness was greatly weakened simultaneously. The (?? 1-Ni3Si+??-Ni31Si12) lamellar eutectoid structure formed in the primary ??-Ni31Si12 phase exhibited better ductility than single ??-Ni31Si12 phase at the cost of relatively small hardness reduction. 相似文献
385.
在一台CNG发动机上研究怠速工况条件下,点火提前角(θi)和过量空气系数(λ)对燃烧排放性能的影响规律。节气门全关,参数调节时,步进电机自动调节,将发动机转速控制在800 r/min。θi在上止点前40~10°CA BTDC变化,λ=1.1时指示热效率和燃烧速度最高;随着λ增加,最高指示热效率所对应的θi越大;θi过大或过小,都会加剧循环变动;λ1.3,平均指示压力循环变动(CoVimep)明显增加;λ=1.1时,NOx排放最高。 相似文献
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中国区域相对价格水平收敛性实证研究 总被引:2,自引:0,他引:2
应用第一代、二代面板数据单位根检验方法对我国省域间相对价格水平收敛性进行实证研究,进而为我国促进区域市场整合提供政策建议。研究结果发现:全国范围内存在相对价格水平收敛;进一步将全国分成东、中、西三大区域,结果发现东部与中部相对价格水平收敛依然可以成立,但西部地区仍然存在一定程度的市场分割;在收敛速度方面,东、中部与全国保持比较一致;CPI各分类商品价格指数以食品类收敛速度最快,而交通、通讯价格指数最慢。 相似文献
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对我军利用民用运力的四种形式,即指令性运输、征用、租用、外包进行了比较分析,为我军根据不同情况灵活运用民用运力提供了参考。 相似文献