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381.
In an effort to restore deteriorating coastal wetlands in Breton Sound, Louisiana, a diversion of Mississippi River water into the estuarine ecosystem has been operated at Caernarvon, Louisiana, since 1991. The diversion was implemented after a relatively long collaborative planning process beginning in the 1950s. The Caernarvon Interagency Advisory Committee, an official panel of stakeholders, considers scientific aspects of the freshwater inflow and stakeholder inputs in developing an operational plan, which internalizes stakeholder conflicts, while accomplishing goals of restoring the coastal ecosystem. Even though fishery representatives are committee members, local oyster fishers filed lawsuits in federal and state courts from 1994 through 2005, claiming damages to their oyster beds. These lawsuits were initially successful in state courts but were reversed by the Louisiana Supreme Court. The federal suits were unsuccessful. Following these lawsuits, voters in Louisiana in 2000 amended the State Constitution to protect coastal restoration projects against lawsuits reflecting increase in overall statewide support. Increasing scientific knowledge has contributed significantly to diversion operation. For better collaborative governance, efforts to increase common understanding among stakeholders will be needed, and a process to compensate interests of stakeholders suffering from impacts of restoration projects at an earlier stage should be institutionalized.  相似文献   
382.
In this feasibility study, we investigate the viability of using Liquefied Natural Gas (LNG) fuel in an open type Ro-Ro passenger ferry and the associated potential challenges with regard to the vessel safety systems. We recommend an appropriate methodology for converting existing ships to run on LNG fuel, discuss all the necessary modifications to the ship’s safety systems, and also evaluate the relevant ship evacuation procedures. We outline the basic requirements with which the ship already complies for each safety system and analyze the additional restrictions that must be taken into consideration for the use of LNG fuel. Appropriate actions are recommended. Furthermore, we carry out a hazard identification study. Overall, we clearly demonstrate the technical feasibility of the investigated scenario. Minimal modifications to the ship’s safety systems are required to comply with existing safety rules for this specific type of ship.  相似文献   
383.
The elastic response of a vehicle to an applied force determines the dynamic performance, comfort, and support of the vehicle, where the elastic response depends primarily on the stiffness of the frame/chassis. Significant variations in the dynamic response of a vehicle are typically achieved with suitable shock absorbing systems, which contribute significantly to whole body flexibility. The defining feature of a go-kart is the lack of devices capable of absorbing shock and dampening vibration. The tires and body of a go-kart, which consist of a frame of welded beams, must also function as a shock absorption system. The objective of this study was to reproduce the elastic behavior of a commercially available Italian go-kart by modeling the frame in a multibody ADAMS environment and to determine the effect of elastic features on the dynamic performance of the vehicle. Frame stiffness was assessed by applying a static torsion moment, while the circular trajectory of the go-kart was evaluated at different speeds and steering wheel angles. The proposed multibody, flexible model was validated by comparing the static and dynamic response of the go-kart in simulated and experimental analyses. The results of numerical simulations demonstrated that this method may be extended to the design of customized go-kart frames and to the tuning of go-karts for specific racing conditions.  相似文献   
384.
Attention is called to evidence that in collisions between vehicles of equal mass, and in single-vehicle collisions, there is unlikely to be a very strong effect of car size on injury severity, and that variation in crashworthiness within the set of car models of a given size has a much larger effect. Consequently, the secondary safety of a national fleet of small cars in the future could be as high as that of a national fleet of large cars today.  相似文献   
385.
A particle-tracking individual-based model (IBM) coupled with a 3-D hydrodynamic model was used to investigate how spatial variability in spawning and nursery grounds may influence transport and retention of sardine (Sardinops sagax) eggs and larvae in the southern Benguela ecosystem. A temperature-dependent Bělehrádek development model based on laboratory growth data was used to determine the duration of one egg and two larval stages. Successful transport/retention depended on each particle's stage of development rather than its age. Results show that recruitment could occur in two distinct nursery areas on the west and south coasts of South Africa. Three viable recruitment ‘systems’ were identified: two are retention-based (spawned and retained on the west coast (WC–WC) or the south coast (SC–SC)) and one is transport-based (spawned on the south coast and transported to the west coast (SC–WC)). In the WC–WC system, the vertical distribution of eggs influenced retention; at intermediate depths of spawning (25–50 m) eggs avoided both offshore Ekman drift and deep cold water. In the SC–SC system, the area of spawning was important; > 50% of eggs from the eastern Agulhas Bank (EAB) were retained in the south coast nursery grounds, whereas very few eggs were transported there from west of Cape Agulhas. In the SC–WC system, area of spawning was also important; 40% of the eggs spawned on the western Agulhas Bank (WAB) were transported to the west coast nursery ground. Sardine life history strategy could be divided between two main systems: the west coast system (spawning on the WAB and WC, and recruiting to the WC) and the Agulhas Bank system (spawning on the central and eastern Agulhas Bank, and recruiting to the SC).  相似文献   
386.
Surface seawater samples were taken in the framework of the GEOTRACES program on “POLARSTERN” expedition ANT XXIII/1 in the Eastern Atlantic in 2005 to study the distribution of the trace elements Hg (mercury), Pb (lead), Cd (cadmium), Cu (copper), Ni (nickel), Zn (zinc), Co (cobalt), Mn (manganese), Fe (iron), and Al (aluminium). With the exception of Hg, results were compared to earlier datasets from 1989 to 1990. The particulate fraction averaged over the transect was calculated to be 49% for Cd, 23% for Mn and 50% for Fe indicating a release of these TEI's (trace elements and their isotopes) from a leachable SPM fraction in the stored and acidified samples.Total Pb concentrations ranged between 5 and 20 pmol kg? 1 in 2005 with highest values in the ITCZ (intertropical convergence zone). In 1989 Pb concentrations were twice as high in the region of the ITCZ, while by a factor of 10–15 higher values were obtained in the North Atlantic.Total Cd and Co are dominated, by different seasonal upwelling regimes (Equatorial upwelling, Guinea Dome, Angola Dome).Total Cu, Ni, Fe, Mn and Al show nearly identical concentrations in 1990 and 2005. For total manganese and aluminium strong maxima (3–4 nmol kg? 1 and 55 nmol kg? 1 respectively) are observed between 23°N and 0°, while the Fe maximum (6–9 nmol kg? 1) is located at 7°N. Total Hg concentrations ranged between 0.5 and 4.5 pmol kg? 1.  相似文献   
387.
Road transport of today has a substantial need for a better information system. The European research programmes PROMETHEUS and DRIVE offer the prospect of new techniques and strategies. The role of information in road transport is analysed from the viewpoint of the individual drivers and from the viewpoint of the traffic manager. All necessary information must be brought together and a complex data‐bank system for road transport should be installed. As examples of advanced information systems the concepts of the ‘Wolfsburg wave’ for in‐car speed recommendation and of the LISB field experiment in route guidance in Berlin are explained.  相似文献   
388.
Abstract

This is an exploration of the political economy of ports in the United States and Great Britain. A number of technical, economic, and political issues concerning ports are examined. Particular attention is paid to the institutional evolution of ports from private to public ownership, and its consequences for port efficiency. The paper concludes with a set of recommendations designed to reverse the trend toward port nationalization in both countries.  相似文献   
389.
P. G. Hooper 《运输评论》2013,33(4):341-367
Because of the importance of transport in promoting economic development, there has been a long‐standing interest in the performance of transport industries and in the conditions which are likely to promote productivity growth. Fundamental to any debate on the subject, though, is the need to advance a satisfactory account of production and a way of deciding when productive performance has changed. This paper points out that there are pitfalls in the common practice of using measures such as output per man‐hour as an indicator of productivity and argues that a thorough understanding of the relationships between inputs and outputs can proceed from a knowledge of the economic theory of production.

The paper describes the relevant theoretical concepts and then examines applications of that theory in transport industries. It transpires that there is a growing literature on the subject, demonstrating a worldwide and multimodal interest in developing more rigorous and satisfying ways of measuring and analysing productivity difference. The techniques employed range from the more complex models at the forefront of economic theory, to rudimentary methods which are, at best, capable of testing only the simplest types of hypotheses. Nevertheless, it is argued that these studies have achieved a remarkable degree of success in enhancing analysis.

There can be no doubt that techniques will undergo further developments. However, it is likely that the greatest successes will come about through improvements in data which will permit applications of more complex, but proven techniques of analysis in relatively neglected areas such as road and maritime transport.  相似文献   
390.
This paper explores the relative influence of factors affecting light rail ridership on 57 light rail routes in Australia, Europe and North America through an empirical examination of route level data. Previous research suggests a wide range of possible ridership drivers but is mixed in clarifying major influences. A multiple-regression analysis of route level ridership (boardings per route km) and catchment residential and employment density, car ownership, service level, speed, stop spacing, share of accessible stops, share of segregated right of away and integrated fares was undertaken. This established a statistically significant model (99% level, R2 = 0.76) with five significant variables including service level, routes being in Europe, speed, integrated ticketing and employment density. In general these findings support selected results from previous research. A secondary analysis of service effectiveness measures (boardings/vehicle km, i.e. the relative ridership performance for a given level of service), established a statistically significant model (99% level, R2 = 0.67) with 6 significant explanatory variables including being in Europe, speed, employment density, integrated ticketing, track segregation and service level. The latter implies that a higher frequency results in higher service effectiveness. Overall the research findings stress the importance of providing a high level of service as a major driver of light rail ridership. The ‘European Factor’ is also an important though intriguing influence but its cause remains unclear and requires further research to elaborate its nature.  相似文献   
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