动车组轮对车轴轮座、车轮轮毂孔粗糙度的分析及建议

通过对动车组轮对组装时车轴轮座、车轮轮毂孔粗糙度的检测及统计分析,根据轮对压装原理,给出了车轴轮座、车轮轮毂孔粗糙度设计参数。     

浅谈改性沥青路面现场热再生技术的应用

改性沥青路面现场热再生技术是一项应用于改性沥青混凝土路面的维修技术,对该项技术施工工艺及施工中应注意的问题进行了介绍。     

宽带CDMA蜂窝系统中控制切换掉线率的CAC算法

呼叫接入控制是无线通信系统中资源管理的重要组成部分,它既要满足用户的服务质量要求,又要有效利用系统中有限的频谱资源.简要介绍基于小区资源占用情况和基于信号质量的两类进行呼叫接入控制的考察角度,并着重介绍预留资源、业务排队、最优化方法等控制切换掉线率的CAC算法及其优缺点分析.     

浮体式水电阻的设计与制作

文章旨在为船厂实现大功率设备的负荷试验,在对比传统负荷试验设备优缺点的基础上,阐述了大功率负荷试验设备的改进方法,并以烟台打捞局船厂建造的3 600t打捞工程船为例,给出了浮体式水电阻制作的设计方案。通过试验证明,该方案达到了大功率设备负荷试验的要求,并且改变了传统的船舶下水后进行负荷试验的方法,缩短了船舶下水调试周期,提高了码头利用率。     

Towards an ‘inland terminal centred’ value proposition

The two main value propositions in international container transport are ‘port-to-port’ services and ‘door-to-door’ services. In port-to-port services, buyers ‘just’ purchase maritime transport from a shipping line. Door-to-door services comprise the total transport chain and include land-based transport. Carriers as well as forwarders offer these door-to-door services. In this paper we provide a qualitative assessment of an emerging third value proposition that is centred around inland terminals (ILTs). Such a value proposition consists of transport up to the ILT, and may have advantages over port-to-port services, such as better leverage of scale economies, better repositioning of empty containers and better alignment with the business model of forwarders. This paper conceptually and empirically explores such a value proposition.     

Entry barriers in seaports

The different types of entry barrier in seaports are analysed and the policies and practices to reduce them are discussed in this paper. In most seaports, economic, regulatory, and geographical entry barriers are substantial and increasing in complexity as ports become embedded in supply chains and multilayered networks with multiple entry-levels. Various entry barriers in seaports are identified through an overview of the relevant literature and their presence is confirmed by empirical data describing them. The case is then made for lowering these barriers. This would be desirable from an economic point of view, since lower barriers strengthen the contestability of markets and increase the level of intra-port competition. The latter might yield substantial benefits, such as fostering specialization and preventing the abuse of market power. Finally, low entry barriers would facilitate the faster implementation of new technologies and business models. In the third part of the analysis, policies and practices designed to reduce entry barriers are examined. The implications are discussed of current national and supranational (EU) policy initiatives aimed to liberalize service provision in seaports. Other (de)regulatory policies that could contribute to the reduction of entry barriers are analysed.     

Book Review: Airline Marketing and Management

Abstract

Public transport policy in the Madrid Metropolitan Area is often deemed as a success. In 1985, an important reform was carried out in order to create a new administrative authority to coordinate all public transport modes and establish a single fare for all of them. This reform prompted a huge growth in public transport usage, even though it reduced the funding coverage ratio of the transport system. Since then, Madrid’s public transport system has been undergoing an increasing level of subsidization, which might jeopardize the financial viability of the city public transport system in the future. In this paper, we present a detailed analysis of the evolution of the public transport funding policy in Madrid in recent years. We found that the increasing level of subsidy can hardly be explained on the basis of equity issues. Moreover, we claim that there is still room for a funding policy that makes the efficiency of the system compatible with its financial sustainability.     

In Search of the Link between Ship Size and Operations

Abstract

Since 1990s the liner shipping industry has faced a period of restructuring and consolidation, and been confronted with a continuing increase in container vessel scale. The impact of these changes is noticeable in trade patterns, cargo handling methods and shipping routes, in short ‘operations’. After listing factors influencing size, growth in container ship size is explained by economies of scale in deploying larger vessels. In order to quantify economies of scale, this paper uses the liner service cash flow model. A novelty in the model is the inclusion of +6000-20-foot Equivalent Unit (TEU) vessels and the distinction in costs between single and twin propeller units on ships. The results illustrate that scale economies have been – and will continue to be – the driving force behind the deployment of larger container vessels. The paper then assesses the link between ship size and operations, given current discussions about the increase in container vessel scale. It is found that (a) ship size and operations are linked; (b) optimal ship size depends on transport segment (deep-sea vs. short-sea shipping, SSS), terminal type (transhipment terminals vs. other terminals), trade lane (East-West vs. North-South trades) and technology; and (c) a ship optimal for one trade can be suboptimal for another.     

矿物掺合料对干粉砂浆性能影响的研究

研究了不同矿物掺合料对干粉砂浆流动性、保水性能和强度的影响.试验结果表明,掺加矿物掺合料对砂浆工作性能和力学性能均有所提高,其中以10％的粉煤灰,20％的矿粉复掺时,砂浆工作性能最好,抗压和抗折强度最高,28d龄期强度分别能够提高75％和25％.     

厦漳跨海大桥现浇箱梁支架整体横移施工技术

厦漳跨海大桥南汊北引桥为分离式双幅预应力混凝土连续箱梁桥,跨径组成为4×(4×45 m)+3×45 m+4×45 m,22号、23号墩位于海中.为了节约工期,22号～23号墩箱梁采用整体横移支架现浇施工,即先搭设钢管支架施工右幅箱梁,待右幅箱梁施工完成,将支架整体横移至左幅施工左幅箱梁.横移支架底端滑梁与轨道梁间设置滚动装置,通过牵引系统实现支架整体横移,横移时利用设置缆风绳防止支架倾覆,并适时进行测量监控,横移到位后将支架与横移主梁锁定,并检查各构件连接情况.