The potential of turboprops for reducing aviation fuel consumption

To assist in aviation systems planning in the context of fuel price uncertainty and environmental regulation, we take a total logistics cost approach and evaluate three representative aircraft (narrow body, regional jet, and turboprop) for operating and passenger preference costs over a range of fuel prices. Homogenous fleets of each vehicle category are compared for operating and passenger costs over a range of fuel prices and route distances and the minimum cost fleet mix is determined. In general, as fuel prices increase, the turboprop offers a lower operating cost per seat over a wider range of distances when compared with both jet aircraft models. The inclusion of passenger costs along with operating costs decreases the number of fuel price and distance pairs where the turboprop exhibits the lower cost. This analysis shows that the aircraft that exhibits the lowest cost is highly sensitive to fuel prices and passenger costs and points to the important balance between saving fuel and serving passengers.     

Deployment of interurban ATT test scenarios (DIATS): Implications for the European road network

The paper summarizes the research results and implications from the DGVII-funded Fourth Framework research project Deployment of Interurban ATT Test Scenarios (DIATS). The objective of DIATS was to identify options available in the short and medium terms, for implementing advanced transport telematics (ATT) systems for motorway-type roads and to develop scenarios of 'highest potential impact' for each of the systems identified. Included are the results of a Delphi study into the most likely deployment scenarios for ATT technologies. The methodology developed to assess the organizational, social, environmental, efficiency, safety and legal concerns associated with new ATT systems is then described. This includes stated preference questionnaires, traffic simulation modelling, driver behaviour assessment using an instrumented vehicle, analysis of accident databases and literature reviews. A multicriteria analysis of the impacts of a range of ATT systems is then presented. In particular, the results discuss the potential impacts of new in-vehicle driver assistance devices such as adaptive cruise control on the operation and effectiveness of existing fixed-infrastructure systems. The paper concludes with a prioritized list of deployment strategies of maximum impact for all of the systems assessed. The research findings are already being applied nationally and a number of field trial assessments that will assist in this are also proposed.     

带式电动助力转向：让转向更精确 操控感更真实

对零部件供应商来说，电动助力转向（EPS）的技术挑战在于，如何达到并超越液压系统的操控感。最新的EPS技术--带式驱动EPS，尤其适用于前桥重量较大的车型，能够满足所有汽车细分市场对转向系统的高要求。     

Automatic fare collection in transit: a synthesis of current practice

Many industries are keeping pace with changing technology in an effort to improve operating efficiency and attract consumers with innovations. The transit industry is no exception, one example being the installation and operation of automatic fare‐collection (AFC) systems. There are many issues to consider in implementing an AFC system, including the type of equipment required and the expected quality of system performance.

This article presents a synthesis of several sources of information pertaining to AFC operations. It includes a discussion of system requirements, and the advantages and disadvantages of system operation. Performance measures of reliability and maintainability are also defined, and AFC systems are evaluated using these measures. Several conclusions are reached concerning current AFC practice.     

本土汽车生产商面临挑战

在本届上海车展上,中国本土汽车生产商占据了4个展厅,全面展示了其在技术和研发方面的最新进展。为了应对日趋激烈的市场竞争和行业合并需求的增长,本土汽车生产商若想保持现在的市场份额,必将迎接更大的考验。     

A GIS-Based approach for estimating truck flow patterns in urban settings

This paper describes how a Geographic Information System (GIS) is being used to help estimate multi-class truck flows in an urban setting. Emphasis is placed on the reasons why this approach is valuable, the specific GIS tools and techniques employed, the value added by employing a GIS-based approach, and the results being obtained. These findings are generalized to describe the benefits that might be expected in other situations where a similar modeling approach is used.     

尾气净化前后的对比检测

马克带着5气体分析仪来到公路上,向我们说明对净化前的尾气进行检测是探测发动机状况的好方法。     

The influence of qualitative factors in Isle of Man ship registration decisions

Open registers have developed in recent years as an economic necessity allowing costs to be cut in response to an over-tonnaged marketplace where low to nonexistent profit margins were the norm under the registers of the traditional maritime nations. These open registers allow shipowners the flexibility to reduce their operating costs by, for example, employing cheap foreign crews. The majority of studies in this area have concentrated, quite rightly, on the economic reasons why shipowners flag-out to registers other than their home register. There are, however, a number of more nebulous reasons why shipowners choose one open register as opposed to another. This paper presents the results of a survey which attempts to deduce these qualitative influences over register choice. The specific context of the Isle of Man register is used to illustrate the importance of such factors.     

Nature or nurture: why do railroads carry greater freight share in the United States than in Europe?

During the 1950s, the share of freight carried by railroads was similar and declining in both the United States and Europe. By 2000, the railroads’ share of freight (measured in ton–kilometers) had reached 38% in the United States while falling to 8% in Europe. This paper examines the reasons for the difference in rail’s share of freight in Europe and the United States. We find that almost 83% of the gap in 2000 is probably due to natural or inherent differences, principally geography, shipment distance, and commodity mix. However, 17% of the gap cannot be explained by these inherent differences and is presumably due to public policies including priority of passenger service, lack of interoperability at borders, service quality and rates, and incentives of the rail operators. We estimate that if that policy gap were closed, railroads’ share of freight in Europe would increase from 8% to 13%.