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571.
Much has been written and spoken about short sea shipping within the European Union (EU) as a means of shifting goods from road to sea and of achieving a sustainable economic development. However, this shift is far from being a general reality, despite the few individual, and success stories that have taken place and the EUROSTAT data suggest that the overall effort has contributed very little towards attaining this desired shift. In the light of this, research was conducted to discover how to put short sea shipping on a more competitive level within European multimodal logistics supply chains. This paper aims at identifying service attributes of short sea shipping operations within multimodal transport chains by means of a questionnaire and, for that, examines the short sea shipping environment and contemporary European logistics trends. The analysis is based on empirical research, involving logistics operators, shippers' associations and intermodal rail operators, and allows an evaluation (based on statistical techniques) of the short sea shipping industry and its competitors. It extends previous work by considering these short sea shipping attributes within a multimodal transport context.  相似文献   
572.
Flux of bulk components, carbonate- and silicate-bearing skeleton organisms, and the δ15N-isotopic signal were investigated on a 1-year time-series sediment trap deployed at the pelagic NU mooring site (Namibia Upwelling, ca. 29°S, 13°E) in the central Benguela System. The flux of bulk components mostly shows bimodal seasonality with major peaks in austral summer and winter, and moderate to low export in austral fall and spring. The calcium carbonate fraction dominates the export of particulates throughout the year, followed by lithogenic and biogenic opal. Planktonic foraminifera and coccolithophorids are major components of the carbonate fraction, while diatoms clearly dominate the biogenic opal fraction. Bulk δ15N isotopic composition of particulate matter is positively correlated with the total mass flux during summer and fall, while negatively correlated during winter and spring. Seasonal changes in the intensity of the main oceanographic processes affecting the NU site are inferred from variations in bulk component flux, and in the flux and diversity patterns of individual species or group of species. Influence from the Namaqua (Hondeklip) upwelling cell through offshore migration of chlorophyll filaments is stronger in summer, while the winter flux maximum seems to reflect mainly in situ production, with less influence from the coastal and shelf upwelling areas. On a yearly basis, dominant microorganisms correspond well with the flora and fauna of tropical/subtropical waters, with minor contribution of near-shore organisms. The simultaneous occurrence of species with different ecological affinities mirrors the fact that the mooring site was located in a transitional region with large hydrographic variability over short-time intervals.  相似文献   
573.
This paper reviews developments in human factors and then draws from a number of "best practice" cases in studying how best to apply behavioral science principles, knowledge, and analytical tools to the engineering design or improvement of systems. Government and other commercial experiences are examined with a focus on the Navy human system integration (HSI) process. Included are discussions facilitated at a workshop session sponsored by the Transportation Research Board of the National Academies. There is general consensus that in addition to using a well-designed or proven process and doing the right things, success is dependent upon attending to a prioritized short list of critical elements. Continued focus on these elements is necessary to successfully apply human behavioral sciences effectively during design, construction, and operation of systems to improve safety, reliability, effectiveness, efficiency, and quality of life.  相似文献   
574.
电动车组的故障中,40%是发生在牵引电动机和电气设备上。因此应采用更经济、更安全、对旅客和维护人员都更方便的新型电动车组代替已经老化的、使用寿命已到期的直流近郊列车。ЗT2A型就是新型电动车组之一。文章介绍了其技术参数,分析了其电路原理和技术特点。  相似文献   
575.
Little information on automotive damper performance above 30 Hz is found in the published literature. Design of vehicles for low levels of noise, vibration and harshness requires attention to higher frequencies. This paper describes research into modelling damper behaviour at frequencies up to 500 Hz. The performance of a monotube damper was measured and the empirical data were used to evaluate a recently published parametric model. Methods of assessing prediction accuracy using transfer and coherence functions, and a wavelet-based transfer function were introduced. Modifications to the model were then developed to improve the prediction of high-frequency behaviour.  相似文献   
576.
577.
介绍了LKAB新型铁矿石货车和机车的技术条件,并阐述了货车和机车用大轴重轮对材料、计算和有关试验。  相似文献   
578.
Block diagram representations of both conventional wheelsets and wheelsets with independently-rotating wheels are developed, with the objective of giving insights from a control engineering viewpoint for studies of actively-controlled wheelsets. The analysis predicts a quasi-kinematic oscillation with independently-rotating wheels which has not been reported before. It also identifies possibilities for control approaches which might be used to stabilise a wheelset without affecting steady-state curving performance.  相似文献   
579.
德国铁路公司自1991年起开行了城际特快列车ICE,它代表了德国铁路当代高速轮轨运输系统.未来新建铁路有可能选用利用电磁技术的磁悬浮列车Transrapid作为公共交通工具.这两种系统的核心功能、支承、导向和驱动的作用方式很不相同.文章对这两种系统的原理作了介绍和比较.  相似文献   
580.
偏压隧道衬砌结构可靠度分析   总被引:2,自引:1,他引:2  
提出了基于有限单元法求解偏压隧道衬砌结构可靠度的方法,开发了实用计算机程序,并给出实际算例。  相似文献   
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