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521.
Road haulage licensing and EC Transport Policy. By K. J. Button. (Aldershot: Gower Publishing Co., 1984.) [Pp.127.] £14.50. Bicycles and Public Transportation: New Links to Suburban Transit Markets. By Michael A. Replogle. (Bicycle Federation, Washington DC, 1983.) [Pp. 171.] US$15.95. Urban Transport in ASEAN. By V. Setty Pendakur. (Institute of Southeast Asian Studies — Research Notes and Discussions Papers Series No. 43, 1984.) [Pp. 65] $4.50 ISBN 9971–902–67–2. The World Railway System. By Bernard de Fontgalland (Cambridge Univerisity Press, 1984.) [Pp. 209.] £16.00. 相似文献
522.
Marcelo E. Lascano Kezi? Pablo L. Durango-Cohen 《Transportation Research Part A: Policy and Practice》2012,46(1):102-122
We compare the passenger transportation systems of Buenos Aires, Chicago and São Paulo. The selected cities represent distinctive combinations of land-use, infrastructure, and evolution of transport policy. Analysis is centered on accessibility to downtown areas, where transportation processes converge in an environment where space is scarce. In two of the three cities institutional arrays that legally establish unified decision making have shown little capacity to launch fare or physical coordination between modes. In two of the three cities the concentration of public transportation supply to historical downtowns has not been an attraction factor, and downtown uses have expanded to less accessible areas. Gentrification in Chicago is also another process showing that land use changes are related to many factors, transportation being only one of them, and not always a necessary one. In all three cases the use of railways, as a set of inherited infrastructures, has seen an increase whose magnitude suggests a link to modal reassignment due to increasing congestion. Scarcity of space in old downtown areas is being counteracted through more intense use, or through the expansion of vertical space for transportation operations. 相似文献
523.
M. Isinibilir L. Svetlichny E. Hubareva I.N. Yilmaz F. Ustun G. Belmonte B. Toklu-Alicli 《Journal of Marine Systems》2011,84(1-2):18-27
During 2005–2008 species composition, abundance patterns, natural mortality rates and salinity effects on zooplankton were studied in the Bosphorus regions of the Black and Marmara Seas. The tendencies to diminish for abundance and biomass of the Black Sea originated zooplankton species and to increase for the proportion of their carcasses in the direction from the Black Sea toward the Marmara Sea were found. The mortality in the Black Sea species increased with depth in the Marmara Sea. The contribution of organic matter of carcasses of the Black Sea originated organisms to bacterial processes in the deep strata of the Marmara Sea was estimated. Different salinity and temperature regimes restrict mutual penetration of the species in these seas. 相似文献
524.
The development of Integrated Coastal Management (ICM) in the Philippines has been underway for more than 30 years. As coastal communities continue to face dwindling resources from both the land and sea, marine protected areas (MPAs) have been regularly utilized as a community-based marine conservation tool. Recently, marine tourism has begun to exert influence as a driver utilized by local communities to promote the establishment of MPAs. Revenue generated through user-fee systems has begun to influence and shape broker–local–tourist (BLT) interactions in Moalboal, Cebu, Philippines. In this article, an account of the social dynamics surrounding MPAs is presented, sources of tension are identified, and recommendations proposed. 相似文献
525.
S. Haider T. Schnipper A. Obeidat K. E. Meyer V. L. Okulov S. Mayer J. H. Walther 《Journal of Marine Science and Technology》2013,18(1):133-143
A simplified model of a low speed large two-stroke marine diesel engine cylinder is developed. The effect of piston position on the in-cylinder swirling flow during the scavenging process is studied using the stereoscopic particle image velocimetry technique. The measurements are conducted at different cross-sectional planes along the cylinder length and at piston positions covering the air intake port by 0, 25, 50 and 75 %. When the intake port is fully open, the tangential velocity profile is similar to a Burgers vortex, whereas the axial velocity has a wake-like profile. Due to internal wall friction, the swirl decays downstream, and the size of the vortex core increases. For increasing port closures, the tangential velocity profile changes from a Burgers vortex to a forced vortex, and the axial velocity changes correspondingly from a wake-like profile to a jet-like profile. For piston position with 75 % intake port closure, the jet-like axial velocity profile at a cross-sectional plane close to the intake port changes back to a wake-like profile at the adjacent downstream cross-sectional plane. This is characteristic of a vortex breakdown. The non-dimensional velocity profiles show no significant variation with the variation in Reynolds number. 相似文献
526.
Julia E. Gardner 《Coastal management》2013,41(2-3):137-188
Abstract The focus of this paper is institutional arrangements for initiative coastal conservation in New Zealand. “Initiative”; conservation refers to positive measures for the protection of the natural environment for reasons related to its inherent worth. Case studies were undertaken in five areas with different biophysical and societal characteristics, where various approaches to coastal conservation are being attempted. In each area, an issue was analyzed to identify conservation policies and their relationship to ecological and human needs, and to administrative and legal frameworks. Analysis demonstrated that initiative conservation policy can encompass user and community needs while maintaining ecological priorities. Institutional arrangements do not appear to restrict the development of this type of policy in New Zealand, but they do limit its formal expression and implementation. Arrangements for cohesive conservation areas spanning the land‐sea interface are particularly lacking. 相似文献
527.
Stringent regulations on exhaust emissions and fuel economy for vehicles have become major issues in the automotive industry. Hybrid electric vehicles (HEV) are one of the crucial alternative plans to current conventional vehicles, but they have drawbacks, which include increases in total hydrocarbon (THC) emission from the engine and deterioration of the combustion stability with frequent stopping and restarting of the engine. Intake port fuel film is evaporated up during the deceleration state due to the fuel-cut. The λ (relative A/F ratio) at engine restart is lean because part of injected fuel is used to form the fuel film in the intake port. This study revealed the behavior of a fuel film in engine stop with fuel-cut and in engine restart with a simulation model. To investigate the fuel film characteristics, a simulation model was applied and validated with a single-cylinder engine. The simulation result shows that λ of at least 1.2 is required for a stable engine restart. The minimum injection quantity of the first cycle for stable combustion is suggested to be at least 240% of the steady-state idle condition. 相似文献
528.
529.
Dynamic analysis of spiral bevel geared rotor systems applying finite elements and enhanced lumped parameters 总被引:2,自引:0,他引:2
X. Hua T. C. Lim T. Peng W. E. Wali 《International Journal of Automotive Technology》2012,13(1):97-107
The dynamics of spiral bevel gears like most high-speed precision gears employed in motor vehicles and off highway equipments
are substantially affected by the structural characteristics of the shafts and bearings. The lumped parameter model is one
of the common tools applied to perform gear dynamic analysis. Even though the lumped parameter approach is computationally
fast and conveniently efficient, it typically uses limited number of coordinates and may not fully account for the shaft-bearing
structural characteristics accurately. In this analysis, the finite element formulation, that can generally represent more
complete characteristics of the shaft-bearing assembly, is employed to enhance the current lumped parameter synthesis theory
using the concept of effective mass and inertia elements. Computational output shows that the enhanced lumped parameter synthesis
model is capable of predicting sufficiently accurate dynamic response when compared to the direct dynamic finite element calculations,
and much more precise response than previous lumped parameter results, especially when the gear dynamics are associated with
the pinion or gear bending modes. Even though this analysis focuses primarily on the spiral bevel geared rotor systems, the
proposed methodology and analysis results can be easily extended to other types of gears. 相似文献
530.
S. H. Jeong J. E. Lee S. U. Choi J. N. Oh K. H. Lee 《International Journal of Automotive Technology》2012,13(7):1133-1140
Recently, the advanced driver assistance system (ADAS), which helps mitigate car accidents, has been developed using environmental detection sensors, such as long and short range radar, lidar, wide dynamic range cameras, ultrasonic sensors and laser scanners. Among these detection sensors, radars can quickly provide drivers with reliable information about the velocity, distance and direction of a target obstacle, as well as information about the vehicle in changing weather conditions. In the adaptive cruise control system (ACCS), three radar sensors are usually needed because two short range radars are used to detect objects in the adjacent lane and one long range radar is used to detect objects in-path. In this paper, low-cost radar based on a single sensor, which can detect objects in both the adjacent lane and in-path, is proposed for use in the ACCS. Before designing the proposed radar, we analyzed the world-wide radar technology and market trends for ACCS. Based on this analysis, we designed a novel radar sensor for the ACCS using radar components, such as an antenna, transceiver module, transceiver control module and signal processing algorithm. Finally, target detection experiments were conducted. In the experimental results, the proposed single radar can successfully complete the detection required for the ACCS. In the conclusion, the perspective and issues in the future development of the ACCS radar are described. 相似文献