电气化动力总成——它会带来什么?

<正>德尔福公司与上海汽车集团股份有限公司("上海汽车")达成协议,将为上海汽车开发的中度混合动力车提供混合动力技术。这一协议的签署具有开创性的重要意义,它将目前中国市场最大的整车制造商上海汽车与德尔福公司的     

Distribution of the transit tax burden in five U.S. metropolitan areas

As transit subsidies increased twelve-fold in the United States between 1970 and 1980, metropolitan areas responded in very different ways to the challenge of financing burgeoning transit costs. The variety of approaches to transit finance has led to variation in the income-redistributive impacts of taxation. This paper reports on the results of disaggregate analysis of transit tax incidence in Chicago, Portland, northern New Jersey, San Antonio, and Phoenix. In cases where alternative tax shifting assumptions can be made, a range of tax burden distributions is calculated. Causes of the variation in redistributive impact are discussed. The analysis concludes by comparing the regressivity of financing transit through higher fares with the regressivity of taxes needed to support subsidies.     

Research contributions to managing transit service reliability

Service reliability problems are a major concern shared by transit system users and operators. Unreliable service leads to additional vehicle requirements and higher operating costs; passengers suffer increased wait time and higher travel time uncertainty, leading to a general dissatisfaction with service and the possibility of seeking other means of transport. Because of the significance of this problem, considerable research attention has been focused in recent years on developing ways to improve service reliability. This paper examines contributions which have been made to managing transit service reliability. This topic encompasses the subjects of vehicle run time, run time variation, headway variation, passenger wait time, and reliability control. Both theoretical and empirical approaches have been undertaken, and each has contributed to our knowledge in addressing the overall problem. Significant contributions to the state-of-the-art are reported and the implications on present practice are discussed.     

A ship's flag—who cares?

Over 60% of ocean trade moves in ships with convenience flags, those of Liberia, Panama, Cyprus and others. Semi-detached flags of Norway, France and the UK are another of the growing devices for avoiding rich-country taxes and labour costs. Shipowners and their customers see little hope for change (taxes and labour) in their political climates at home, but they need some workable governing structure to assure safety, payment of bills, protection of the environment and decent service. It follows that all maritime nations, especially the USA and Canada, should pay more attention to the creation and observance of International Conventions.     

The compressive behavior of advanced double hull structure—A review of current research at David Taylor

It has long been recognized that the compressive behavior of primary ship structural components plays a vital role in the design of surface ship hulls. This is equally as true for the new advanced double hull concept as it is for the more conventional surface ship configurations. What is different, however, is the nature of the structural mechanics phenomena which must be addressed due to the double hull's more radical departure from conventional design and construction practices. With increasing interest and attention being shown in this new concept, the David Taylor Model Basin has over the past few years initiated a number of research efforts which have and are continuing to address various aspects of the behavior of double hulls and their components to primary compressive loadings. These studies have as their ultimate goal the development of practical, user oriented design methods for double hull structure and as such currently focus on more approximate, rather than mathematically rigorous, approaches to the various structural phenomena being considered. This paper is in essence a progress report on a selected number of these efforts and describes the results achieved to date as well as the ongoing efforts and those planned for the future. This report focuses primarily on three recent studies: (1) a preliminary look at the relative significance of local versus general instability failure of double hull structure; (2) small scale experimental analysis of double hull sections using rigid vinyl modelling; and (3) the application of beam-on-elastic-foundation analysis methods for high aspect stiffened plates as it relates to double hull structure. In addition to these major topics, the report also includes a brief discussion of other ongoing and planned efforts relevant to the advanced double hull.     

The state-of-the-art of “comprehensive” planning

Planning occurs as a part of governmental operations wherever decision-making happens. For US metropolitan areas, the locuses of decision-making are multiple, ranging in scale from very small jurisdictions up through the hierarchy to state and federal levels, and in function from general governments to many special-purpose agencies — transportation, health care, education, etc. Almost all might affect or be affected by urban transportation decisions and actions. Since no one of these units of government is comprehensive in authority and activity, there is no single, centralized planning operation that is truly comprehensive. Pluralistic planning is increasingly trying to foresee and to accommodate the interactions among the various levels and functions. Instead of fragmenting, with the fragments pulled apart and insulated, we need to move toward partitioning, not merely to delimit boundaries but also to identify interfaces. This movement is hampered by the differentials in the development of the state-of-the-art of the technical planning process now used by the several levels and functional units of government. This is most advanced, and most effective, for small, homogeneous suburban jurisdictions primarily concerned with guiding and controlling physical development; it is in disarray in central cities trying to cope with social and economic problems as well as with physical deterioration; at the metropolitan scale it is highly developed technically but not very influential. There is a trend toward a network of planning activities that recognizes and facilitates interrelationships and interactions, both vertically among functional boundaries and horizontally across geographical-scale distinctions — a trend toward the comprehensive —but we have a very long way to go.Paper prepared for the Highway Research Board Conference on Organization for Continuing Urban Transportation Planning.