新型微结构船体防污表面的制备与分析

为解决船体表面生物污损现象造成的船舶运行阻力增大、寿命降低等问题。本文研究利用反应离子刻蚀(RIE)技术方法,制备具有特定微结构的304不锈钢防污表面,选用三角褐指藻(P. tricornutum)和小球藻(C. pyrenoidosa)为目的污损生物,对微结构表面开展防污实验。使用接触角测量仪分析微结构表面的浸润性,利用激光扫描共聚焦显微镜(LSCM)和ImageJ软件对微结构表面的防污性能进行评价。结果表明:微结构表面接触角增大至108.5°,为疏水表面;微结构表面对三角褐指藻和小球藻的抑制率达到91.5%和89.8%,显示出优异的防污能力。该新型微结构表面为船舶绿色防污减阻表面的设计提供依据。     

钢丝绳聚氨酯水泥复合材料加固损伤空心板梁试验研究

为研究钢丝绳聚氨酯水泥复合材料加固损伤空心板梁的力学性能,进行加固条件下损伤空心板梁抗弯性能模型试验,分析板梁挠度、裂缝宽度和承载能力变化规律,研究复合材料加固损伤空心板梁的破坏机理。试验结果表明:采用钢丝绳聚氨酯水泥复合材料加固经过预压的损伤空心板梁,其破坏过程分为钢丝绳断裂、复合材料开裂和整体结构受弯破坏3个阶段,属于适筋梁破坏;此板梁的实测屈服荷载和极限承载力比未加固空心板梁分别提高28.60%、40.00%,相同荷载作用下的挠度降低22.81%,最大裂缝的宽度减小52.73%,梁体延性提高57.14%,梁体的屈服阶段延长,空心板梁的安全性提高。采用钢丝绳聚氨酯水泥复合材料加固损伤空心板梁可显著改善梁体的整体承载性能,提高安全性。     

Can passenger flow distribution be estimated solely based on network properties in public transport systems?

Transportation - We present a pioneering investigation into the relation between passenger flow distribution and network properties in public transport systems. The methodology is designed in a...     

Derivation of train arrival timings through correlations from individual passenger farecard data

Transportation - In this paper, we propose a method for estimating the timings at which trains arrive and depart from stations using passenger farecard data and knowledge of the network topology....     

HMB Reflectors: A New Horizontal Retro‐reflecting System to Improve Safety at Pedestrian Crossings

Abstract

Each year more than 1000 pedestrians are injured in accidents on pedestrian crossings in Switzerland. The accidents often occur in darkness, twilight or poor visibility during rain at locations without sufficient public street lighting because vehicle drivers notice the pedestrian crossing too late or overlook it altogether. Pedestrian crossings can be made significantly easier for vehicle drivers to recognize at night and in poor visibility by means of HMB reflectors. When crossing sites are made more conspicuous with high horizontal retro‐reflecting markers, the readiness to stop increases. The reflectors can thus contribute to improving road safety at pedestrian crossings. This new low‐cost measure has a wide range of applications. The new reflector system is currently gaining ground in Switzerland and several other European countries.     

The History of the Transport Future—Evaluating Dutch Transport Scenarios of the Past

Abstract

This paper examines 42 business‐as‐usual (BAU) scenarios for future transport and traffic development in the Netherlands from the period 1970 to 2000. An important aspect of these scenarios is that they indicate the potential future state of the transport system if the policies in place at the time continue unchanged, thus raising issues which may require a policy response. This paper shows that in most of the important BAU transport scenario results of the past in the Netherlands, such as future car use and transport emissions, the policy makers were not misled. The prognoses for traffic congestion are an important exception as they underestimated the congestion problems that would arise. This paper shows that, based on the research it examines, BAU transport forecasting is an inaccurate practice. It is recommended that the BAU scenario designer communicates this high inaccuracy, enabling the policy maker to include the inherent future uncertainty in their decision‐making.     

Port Economics,Policy and Management: Content Classification and Survey

This paper presents a taxonomy and analysis of the content of published research in port economics, policy and management (port studies). The recent increase of these publications suggests a growing interest in the study of ports. However, the research characteristics and directions of this research field are unidentified. This paper provides a systematic analysis of port studies published during the period 1997–2008. A comprehensive cross-citation and analysis of the themes, approaches and findings of all 395 relevant journal papers identifies the extent to which the research field is maturing, and the leading papers. This paper also presents an extensive analysis of the content, based on the classification of all port studies into seven research themes. For each theme, research topics, widely used research questions, concepts and research methods and the most important research findings are discussed. Finally, we identify emerging research challenges and research questions that still need to be answered.     

Short Sea Shipping in Supply Chains. A Strategic Assessment

The feasibility of implementing short sea shipping (SSS) between two specific ports has been typically approached on the operative level, in terms of time and cost for a specific origin–destination pair. This paper focuses on the strategic level. Particularly, its goal is to study the potential of SSS in different industrial sectors by analysing their freight-distribution strategies. To achieve the objective, some standard freight-distribution strategies are defined based on the requirements of the industry, the demand and the product being transported. The information is complemented with a survey of more than 100 Spanish companies distributing internationally. As a result it is concluded that there are economies of scale related to the size of the carrier (the ship) and its capacity to absorb the variability in demand. This potential increases with the cargo value. Additionally, a framework of supply/distribution chains is provided which can help to identify potential customers/sectors and the feasibility of new potential shipping lines. The value of this paper resides in its approach (strategic, instead of operational/tactical), and the solid groundwork point provided for future researchers.