Effect of wheel-slip prevention based on sliding mode control theory for railway vehicles

It is important to consider the robustness when designing brake control systems, because of the model's uncertainties that result from the nonlinear characteristics of wheel-to-rail adhesion forces and brake material friction coefficients. This paper presents the experimental results from the new wheel-slip prevention control using nonlinear robust control theory. The authors performed experiments for the proposed wheel-slip prevention control to compare it with the conventional control laws. The experimental results proved the comparative effectiveness of the proposed control and showed high brake performance under nonlinear characteristics of brake dynamics.     

Exploring the impacts of road surface texture on tyre/road noise - A case study in Hong Kong

The impacts of road surface texture on tyre/road noise are explored by analysing field data applying fast Fourier transform technique to tyre/road noise spectrum analysis. The results indicate that the tyre/road noise can be higher at lower frequency bands but lower at higher bands. Cluster analysis on surface texture in terms of wavelength identified three cluster groups that centred at 1.32 mm, 3.65 mm, and 5.11 mm have different impacts on noise. The shorter wavelength group suppressed tyre/road noise, medium group aggravated it and the high wavelength group were outliers.     

The ratinality of conference pricing and output policies. Part 1 *

The general recession in the international economy and an increasing desire on the part of the developing countries to establish or expand their own national fleets has led to increased protectionism in international shipping. This paper discusses the various aspects of protectionism in the light of the UNCTAD code of conduct for liner and bulk shipping.     

A land‐use planning model for coastal zone management

Abstract

In this article we consider a linear programming model for assessing the aggregate impact of land‐use activities scattered over a large area on the resultant pollutant concentrations in coastal waters. The dispersion to coastal waters of the adverse environmental loads generated by the land uses is described by a set of transport coefficients that measure the attenuation of pollutants, such as industrial BOD, carried to the coast along surface drainage basins. Further dispersion in the waters caused by tidal action is then described by the simple procedure know as “pollution susceptibility.”; The model seeks to minimize the steady‐state concentrations of pollutants by establishing an optimal spatial configuration of residential, commercial, and industrial land uses. This configuration is constrained by a number of restrictions based on local and regional targets for growth and development. The methodology discussed in this article is intended to be useful to regional planners, and is based on a study conducted for the Long Island area.     

A Review of Whale-Watching and Whaling with Applications for the Caribbean

Whale-watching is a significant and growing tourism industry worldwide. Whaling has a long history and, although largely curtailed today, still occurs in a few countries around the world and in the Caribbean. Whaling has been labeled an incompatible activity with whale-watching because, in some cases, it reduces the number of whales available for use and changes whale behavior. Moreover, in some situations, whale-watching generates greater revenue than whaling, and whaling may detrimentally affect the larger tourism industry because of negative attitudes toward whaling by whale-watchers, other tourists, and host communities. This article examines the potential impacts of whaling on the whale-watching and tourism industries, and places these impacts in the Caribbean context. In doing so, the article outlines the history and current status of whale-watching in the Caribbean, outlines other potential constraints, and highlights the need for research about the impacts and roles of these industries. In the highly competitive global tourism industry, maintaining and nurturing a country's tourism image is critically important.     

Electromagnetic valve train for gasoline engine exhaust system

Electromagnetic valve train (EMVT) in camless engine offers large potential for both part load fuel economy and high load engine torque. However, it is more difficult to be applied on exhaust system than intake system. Because the gas pressure brings high demands for driving force, especially at high engine speed and full load. Based on the working characters of actuator, a method by increasing the transient currents in windings during valve’s opening motion is suggested to overcome the gas pressure. But this will cause more energy losses and heat. In order to make the EMVT used on exhaust system better, quantitative analysis is carried out against the additional power consumption caused by gas pressure under different conditions. Furthermore, an approach is introduced to define the optimal exhaust valve opening motion at full load conditions. It aims at making a better compromise between the engine power output and exhaust valves’ power consumption, thus both the efficiency of EMVT and engine performance are enhanced.     

Evaluation of driver satisfaction of travel information on variable message signs using fuzzy aggregation

Driver satisfaction regarding travel information provided by variable message signs (VMS), which are part of the Nam‐Mountain Tunnel ATIS, was evaluated using fuzzy aggregation. Application of fuzzy aggregation to analyze driver satisfaction allows one to represent the variability and complexity of human perception with great fidelity. A fuzzy weighted average using two sets of fuzzy membership functions was applied to evaluate individual satisfactions of delay and travel time information provided. Then, those individual satisfactions were aggregated to estimate the driver group's overall satisfaction. The evaluated overall satisfaction was 0.65 for delay information and 0.63 for travel time information. Through these results, it was found that users of the travel information provided by the VMS in the Nam‐Mountain Tunnel ATIS were somewhat satisfied with the service quality. Those overall satisfactions were compared with a conventional weighted average and traffic operational effects to demonstrate the usefulness of the developed fuzzy method.     

抗磨损低摩擦的活塞裙部涂层

介绍了一种经久耐用的可以减小汽油机摩擦功和CO2排放的新型抗磨损低摩擦的活塞裙部涂层。适应了当前高强化发动机和节能减排的市场需求。     

Personal security as a transport issue: a state‐of‐the‐art review

The possibility of experiencing attack, assault, violence, robbery, harassment or other anti‐social behaviour has become an important influence on traveller decision‐making. Fear and apprehension about personal security can affect all aspects of travel choice (e.g. choice of route, mode, time of journey, etc.), including whether to travel at all. Indeed, in some locations an informal curfew is reported to operate. However, both the degree and widespread extent of such fears indicate that unacceptable constraints on personal liberty do exist in many locations.

This paper firstly reviews the extent and nature of the problem considering recorded crime statistics, reported levels of fear and apprehension when using transport facilities and subsequent modifications to travel behaviour. Secondly, a range of possible responses by transport operators, policing agencies and national and local government are examined under four broad headings: policing and staffing; situational crime prevention; social crime prevention; and the level and quality of transport service provision.

It is concluded that personal security considerations need to be explicitly incorporated into decisions concerning the design, planning, operation and management of transport systems. It is also important that institutional structures exist to permit the issue both to be recognized and tackled.     

One manufacturer's approach to improving jet transport fuel efficiency

In the face of rapidly escalating costs of aircraft fuel, since the early 1970s, the aerospace industry has embarked on a program of measures to reduce fuel consumption. This article describes an integrated set of measures which have been undertaken by Lockheed‐California to improve the fuel requirements of the Tristar, a wide‐bodied three engine medium to long range aircraft. Measures include operational changes, improvements to maintenance practices, long term hardware modifications and technological advances.