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411.
David A. Tarnas 《Coastal management》2013,41(4):275-303
Abstract The U.S. National Marine Sanctuary Program was established in 1972 by Title III of the Marine Protection, Research, and Sanctuaries Act (16 U.S.C. §1431 et seq.). In this article, we discuss the development of the sanctuary concept, and the original intent of Congress, and analyze how it was applied by the sanctuary program. Differences in interpretation of the program's purpose are examined, including discussion of the multiple‐use management concept, an important but controversial management technique used in the sanctuaries. The continuing efforts by Congress and the National Oceanic and Atmospheric Administration to clarify the program's purpose are investigated. The program's administrative history is explained and the current sanctuaries and active candidates are briefly described. In light of the 1988 reauthorization of the Marine Sanctuary Act, the current issues facing the program are analyzed. Finally, we draw conclusions and make recommendations for the program's future. 相似文献
412.
David Silcock 《运输评论》2013,33(3):263-273
The problem of deaths and injury as a result of road crashes is now acknowledged to be a global phenomenon with authorities in virtually all countries concerned about the growth in the number of people killed and seriously injured on their roads. The World Health Organization has declared that its annual World Health Day in 2004 will have the theme 'Safe Roads', and several organizations, including the World Bank and the Global Road Safety Partnership, are supporting this initiative to raise the profile of road safety in the public and political minds. 相似文献
413.
R. S. Farrow, with J. M. Broadus, T. A. Grigalunas, P. Hoagland III, and J. J. Opaluch. 1990. Managing the Outer Continental Shelf Lands: Oceans of Controversy. New York: Taylor & Francis New York, 168 pp., paper. Richard A. Kenchington. 1990. Managing Marine Environments. New York: Taylor & Francis, 248 pp. 相似文献
414.
415.
Ship structures are submitted to variable cyclic loading during navigation. The cyclic motion of waves induces variable and complex loadings in the structure, which could generate fatigue damage. Moreover, most of these metallic structures are welded assemblies. This technique generates local stress concentrations at the weld toe, which becomes a critical area regarding fatigue. In previous works, a methodology to predict fatigue life was developed and tested on butt-welded and cruciform joints. The present work focuses on other welded assemblies in order to extend fatigue crack initiation life evaluation to a wider range of ship details. The strategy could be split into two steps. First, a finite element calculation is performed under constant or variable amplitude loadings, in order to analyze the elastic shakedown of the structure. To characterize the material heterogeneity of the welded joint, experimental tests together with micro-hardness measurements, are performed on a simulated heat-affected zone. If there is a shakedown in the structure, a post-treatment is applied to predict the fatigue crack initiation. It is based on a two-scale damage model, initially developed by Lemaitre et al. and again includes the heterogeneity of fatigue properties. To validate this methodology, some experimental tests have been performed on welded assemblies which are typical of shipbuilding applications, using a fatigue machine. These comparisons between experimental and numerical fatigue lives are encouraging. 相似文献
416.
David Hilling 《Maritime Policy and Management》2013,40(1):13-20
The US Shipping Act of 1984 permits ocean liner vessel operators and shippers to make use of service contracts to further their mutual interests. However, starting from the very day this novel provision was incorporated into the Act, it has remained as a bone of contention between shippers and carriers serving US trade routes. This article highlights the major issues that have sprouted subsequent to the introduction of service contracts in ocean liner shipping. The author concludes with some logical suggestions to fine-tune the Act, without interfering with its legislative framework. 相似文献
417.
Harvey G. Young 《Coastal management》2013,41(1-2):213-222
Abstract The Duplin River Estuarine Sanctuary was dedicated by Governor George Busbee of Georgia in December 1976. The sanctuary includes the entire Duplin river, related wetlands, and much of the contributing uplands, which extend over 7500 acres. Much of the upland lies on Sapelo Island, neighboring a state wildlife management area, a state natural area, and a community of black families that have lived and worked on the island for many generations. The sanctuary was acquired, in part, with funds from the National Oceanic and Atmospheric Administration, and will be managed for research and educational purposes. The management policy will be designed to avoid artificial or manipulative management control, to protect natural processes and systems, and to promote attainment of scientific objectives. 相似文献
418.
419.
This study aims to determine whether ramp meters increase the capacity of active freeway bottlenecks. The traffic flow characteristics at 27 active bottlenecks in the Twin Cities have been studied for seven weeks without ramp metering and seven weeks with ramp metering. A methodology for systematically identifying active freeway bottlenecks in a metropolitan area is proposed, which relies on two occupancy threshold values and is compared to an established diagnostic method – transformed cumulative count curves. A series of hypotheses regarding the relationships between ramp metering and the capacity of active bottlenecks are developed and tested against empirical traffic data. It is found that meters increase the bottleneck capacity by postponing and sometimes eliminating bottleneck activations, accommodating higher flows during the pre-queue transition period, and increasing queue discharge flow rates after breakdown. Results also suggest that flow drops after breakdown and the percentage flow drops at various bottlenecks follow a normal distribution. The implications of these findings on the design of efficient ramp control strategies, as well as future research directions, are discussed. 相似文献
420.
John Stanley David A. Hensher 《Transportation Research Part A: Policy and Practice》2008,42(10):1295-1301
The Thredbo Conference series has developed the idea of negotiated performance-based contracts as effective public transport service delivery mechanisms, with trusting partnerships between authority and operators providing an environment likely to maximise the performance of this delivery mode. However, there is a distinct lack of relevant case study material on trusting partnerships in public transport to affirm this proposition. This paper seeks to redress the balance. It outlines the system development directions that are being implemented for bus services in Melbourne, Australia, and the way that a broad-based constituency has been built to support those directions. It then illustrates the extension of the tactical trusting partnership approach between purchaser and provider to the level of the individual operator contract, showing how this should create a flexible yet disciplined environment to manage and cope with change and growth. The broad nature of the new contracts is summarised and, building on the findings from Thredbo 9, processes that are being implemented to manage the on-going relationship between purchaser and providers are outlined. Finally, the paper argues for extending KPIs beyond the operator to encompass the authority/regulator and the partnership of authority/operator, to extend performance pressures beyond the operator and recognise the interdependence of partners in a true partnership. 相似文献