Shape Optimization of Elliptical Road Containers Due to Liquid Load in Steady-State Turning

A numerical analysis of liquid load in elliptical road containers undergoing a steady-state turning manoeuvre is presented for containers of unrestricted size and for containers of fixed capacity. The liquid load is expressed in terms of the horizontal and vertical forces and the overturning moment created by these forces around the middle bottom point of the container. The moment is obtained by integrating the liquid free-surface equation and using numerical calculation of the resulting expressions. An optimization study with an objective to minimize the peak overturning moment is performed on containers of fixed capacity to identify the optimal height/width ratio of the container. The results of this investigation being of a general nature, i.e. with no restriction for an application, are particularly intended for road tankers under a steady turning manoeuvre, where they can be applied with high degree of accuracy.     

Young drivers and graduated licensing: The Ontario case

Despite improvements in road safety over the past several decades, accident rates remain high for young drivers. One accident countermeasure that is expected to improve the safety record of this group is graduated licensing. The philosophy behind this licensing system is that novice drivers, of whom the majority are young, should be restricted to relatively safe driving environments during the initial learning period. Graduated licensing was implemented in the Province of Ontario, Canada in 1994. The objective of this study is to estimate the potential benefits and costs for young drivers associated with two components of the Ontario graduated licensing package: the late-night driving curfew and the high-speed roadway restrictions. Based on accident and travel data for the year 1988, accident-involvement rates per kilometre driven were calculated for different driver groups for various combinations of time of day and roadway speed limit. These rates were then applied to the expected mobility profiles of young drivers affected by graduated licensing. The results of the study support the late-night curfew and suggest that this component of the licensing package should reduce total accident involvements for the affected group by up to 10 percent and fatal accident involvements by up to 24 percent, while reducing their total driving by only four percent. By contrast, the empirical evidence suggest that the high-speed roadway restrictions are likely to increase accident involvements, and thus it is strongly recommended that this component of Ontario's graduated licensing package be changed.     

Basic Analytical Study of Pantograph-catenary System Dynamics

For a high speed electrical rail system, good dynamic performance of the pantograph-catenary system is vital for smooth and continuous current collection. It has been known for many years that to achieve this the head of the pantograph should be made as light as possible and the average stiffness of the catenary should be high. These conclusions, however, have been reached by numerical modelling and operational experience. In this paper the pantograph-catenary system is modelled as a time-varying, single degree-of-freedom system to facilitate an analytical investigation of the system dynamics. Although the model is very simple, it allows physical insight into the dynamic behaviour of the system, and because the excitation is parametric it also allows the stability of the system to be investigated. The finite element method is used to determine the catenary characteristics and Floquet theory is used to analyse the behaviour of the coupled system.     

Analysis of Driver's Decelerating Strategy in a Car-following Situation

This report describes a decelerating driver-model expressed by driving mode transition in car-following situations. The assumptions for constructing the model are that decelerating strategy of a driver is classified into several simple driving modes and that a driver changs his driving modes based on his perceptible characteristics and experiential rules. Deceleration action is divided into three states; following, standing and braking, which are applied to the model. The model has two paths for driver's decelerating action, one of which is selected by the driver based on the perceptible characteristics and experiential rules. The suitability of the model has been experimentally verified.     

高压共轨喷油器精密偶件的泄漏分析

高压共轨电控喷油系统中，随着燃油喷射压力的大幅度提高，燃油的粘度-压力效应、粘度-温度效应凸显。作者分析了高压共轨喷油器精密偶件中的泄漏问题，得出的结论是：考虑了燃油的粘压效应、粘温效应后实际的泄漏量并不十分严重；如果考虑油液的极化效应、进口起始段的效应以及环形槽的影响，实际泄漏量可能还会减小。     

Building Philippine Local Government Capacity for Coastal Resource Management

The responsibility for managing coral reefs and other coastal resources was largely devolved to coastal municipalities and cities in the Philippines in 1991 with the passage of the Local Government Code. Devolution of powers and responsibilities to local government has paved the way for mainstreaming coastal resource management at the local level. However, the capacity to carry out this mandate has only recently begun to mature as municipalities and cities gain an increased awareness of the importance of coastal resources to communities and economic development. Approaches and strategies to increase local government capacity for coastal resource management are described based on the experiences of the Coastal Resource Management Project of the United States Agency for International Development. Qualitative and quantitative data are used to illustrate the possible impact of these capacity building efforts and to describe the current capacity of local government to undertake coastal resource management. After five years of project implementation, coastal municipalities have increased technical capacity, have allotted financial resources, and have achieved key performance benchmarks in the delivery of coastal resource management as a basic service.     

铁路牵引用直驱式永磁同步电动机的无位置传感器控制

提出了一种表面式永磁同步电动机无位置传感器的控制方法,适用于要求逆变器利用率高且开关频率低等限制条件的大功率牵引驱动系统.采用含电机电压模型和电机电感模型的观测器,在低速时注入测试信号,可以得到位置和速度信号.阐述了基本估计方法的改进.在实验室用28 kW标准伺服电机成功地验证了该方法.     

城市轨道交通最新技术及评定

文章对城市轨道交通系统进行分类、并对其最新发展和商业化运营趋势及其所用的安全评定方法进行了论述.     

EH200型直流供电电力机车的开发

介绍EH200型直流供电电力机车的开发.为证实机车性能满足基本要求,至2001年6月完成了样机试验,并从2001年7月至2002年3月牵引列车进行了运营.通过这些试验和运营,证实该种机车能满足规定的性能,包括与地面设施的匹配.     

冲绳城市单轨运输系统

简要介绍了冲绳城市单轨运输系统的设施和车辆概况.