基于氯离子分布的氯离子渗透参数计算的新方法

根据混凝土中氯离子的分布对氯离子侵入性能进行评价时,混凝土粉末样品的采集,氯离子含量的测试和表达方式,均可对评价结果产生影响。在干湿循环条件下,以理论上的表面氯离子浓度为主要评价参数对氯离子的渗透性能进行评价的方法不尽合理。通过对暴露26年后的青岛北海船厂码头中大量的混凝土芯样中氯离子分布的分析和计算,结合其它文献中氯离子分布的数据,提出了以扩散区与对流区界面为扩散表面,以界面处的氯离子浓度为扩散表面浓度,评价氯离子侵入性能和进行寿命预测的方法。     

An introduction to airport APM systems

The purpose of this paper is to provide an introduction to the nature and purpose of airport automated people mover (APM) systems. Our objective is to provide a convenient research tool for persons seeking an introduction to the airport APM industry. Included are illustrations of typical system designs; a listing of existing airport APM systems, including a tabular presentation of selected data; an organization and discussion of the history and evolution of the existing systems; and a status report on current developments in the APM industry.     

Modelling and Control of an Automated Vehicle

We present a vehicle model that includes the vehicle dynamics and a vehicle tire model. The model developed is then used for conducting steering analysis of an automated vehicle. We test the developed model on a step lane change maneuver and propose a model-reference based controller for remote control of a vehicle. Stability analysis of the closed-loop system using die Lyapunov approach is included.     

Grounding experiments on soft bottoms

To verify a theoretical analysis procedure for calculation of the hull girder response of ships running aground, a series of large-scale ship grounding experiments was performed on an artificial island made of engineered fill. The tests were conducted by running a condemned fishing vessel up on selected beaches of the island with velocities ranging between 2m/s and 5.5m/s. During the tests, surge, heave, and pitch accelerations were measured and also the deformations of the beach and the ship bow. Based on these accelerations, rigid body velocities and motions were determined. The forces arising from the interaction between the bow of the vessel and the seabed were determined by solving the equations of motions. This article describes the analysis of the measured results and a comparison of the results from the full-scale measurements with results from a recently developed analysis procedure for grounding on soft bottoms. Presented at the International Conference on Technology for Marine Environment Preservation (MARIENV '95), Tokyo, Japan, September 24–29, 1995.     

The effects of marine cargo delays in law and commerce

With the development of door-to-door intermodal services and the advent of just-in-time supply systems, punctual delivery of cargoes is more than ever a priority both for shippers and for shipowners. This paper is about the incidence of delay in transportation, particularly in the marine mode, and its legal and commercial consequences.

The fundamental legal obligations of marine carriers have always included delivery with dispatch. Thus the law would seem to support the commercial expectations of shippers for reliable performance. The authors discuss the nature of these obligations, investigate their adequacy under modern conditions of trade and report on a survey of Canadian shippers and consignees.

The authors conclude that there appears to be a divergence in the toleration of delay, but that few of the Canadian companies suffering unacceptable delays received, or even sought, financial compensation and none of them planned to do more. The authors speculate about their reasons for absorbing the losses incurred through unacceptable delays. The evidence from the survey is that shippers, in spite of their dissatisfaction with the resolution or outcome of incidents of unacceptable delay, are loath to seek compensation through legal means, but instead prefer to resort to a range of commercial actions.     

Causes of casualties and the regulation of occupational health and safety in the shipping industry

The aim of this paper is to investigate maritime safety from an occupational hazards perspective as opposed to a maritime casualty perspective. It is recognised that safety in shipping should encompass casualties arising from accidents occurring in the course of performing normal seafaring duties, not just those arising from technical defects or maritime disasters. The paper discusses an investigation involving a survey of 19 flag states and two detailed studies of records kept at the Hong Kong and Singapore maritime administrations. The results indicate that occupational accidents account for a significant proportion of fatalities at sea. The statistics presented specify the ship types that are most at risk, as well as the types of occupational hazards that can most frequently lead to accidents and fatalities. The results of this study indicate voids in the process of investigating fatalities that relate to occupational accidents. These results also indicate inadequate investigation of events and causes. The creation of a database of such information could potentially be used for the development of appropriate regulations that could prevent fatal and non-fatal occupational accidents through regulatory processes.     

双层客车用中频电位隔离的电源

德国铁路公司新双层客车从2004年起使用创新的电源.用中频电位隔离的高压逆变器取代至今用16.7 Hz单相变压器的由1 000 V列车母线供电的一般技术.采用这种创新电源可减轻重量并有其他技术优点.     

A capacity related reliability for transportation networks

A capacity related reliability for transportation networks with random link capacity is introduced. It is defined as the probability that the road network can accommodate a certain level of traffic demand, and is built on the concept of network reserve capacity. Network reserve capacity is defined as the largest multiplier applied to an existing origin-destination demand matrix that can be allocated to a transportation network in a user-optimal way without violating the link capacities. Due to large variability associated with link capacities, a probabilistic approach is adopted to model the different physical and operational factors that often degrade the capacity of roadways. A Monte Carlo simulation procedure is developed to estimate the capacity related reliability measure. Numerical results are provided to demonstrate the feasibility of the approach.     

Multimodal traveling and its impact on urban transit network design

Multimodal trip making, that is trips using a combination of several modes between origin and destination, is expected to be beneficial to society and might offer advantages to the traveler as well. This article looks at some of the implications of multi‐modality in trip making for the design of urban transit systems since these play an important role in multi‐modal transportation systems. In this respect, the article looks at the strategic design characteristics of urban transit networks, that is line density, stop density and service frequencies for the case of multimodal access to urban transit networks and for hierarchical network structures in urban transit systems. The analyses show that multimodal access does not require alternative network structures. For hierarchical network structures it is concluded that these are primarily determined by the hierarchy in demand densities and thus by hierarchy in urban structures.