L’intégration territoriale des gares sur lignes à grande vitesse en France : une approche typologique

Construction of high-speed railway lines (Lignes à Grande Vitesse — LGV in French) in France and in other European countries has brought considerable changes in railway accessibility for the areas linked to this fast transport network. The new stations on the high-speed lines take maximum advantage of such relational gains. However, mass transit access to these stations often constitutes a problem. Their locations, which are frequently exurban, are not determined by considerations involving efficient mass transit service links, and especially railway links. This situation creates difficulties for prior and subsequent passenger travel, and it means that the local players have to develop new access routes of variable quality. The present article puts forward a quality analysis covering territorial integration of high-speed railway stations via typology of the interactions between these new service points and the established stations in central locations. In a context marked by the increasing burdens placed on local authorities regarding financing for new high-speed railway infrastructures, we examine whether these changes in the players’ roles encourage enhanced consideration as to positioning of high-speed railway stations in relation to accessibility criteria for mass transit.     

Safety in Greek coastal shipping: The role and risk of human factor revisited

The comprehensive analysis presented in this paper investigates the links and comparative assets between human factor and other factors that are important determinants of maritime transport risk. In this outline, the identification of factors, such as age and ship size, that can be statistically linked (i.e. statistical significance) to whether an accident in a passenger vessel can be attributed to human factor or other causes is addressed accordingly. This way, the role of human factor in relation to safety of Greek coastal shipping is revealed and the spotlight is able to focus on the various aspects and points that manifest the importance of human element in the maritime industry. The risk assessment of the transportation with Greek passenger ships is being used in order for the safety level of Greek coastal shipping to be adequately estimated. Moreover, the comparison between the values of risk for accidents caused by human factor and those attributed to other causes is an established way to bring to the fore the unbroken relationship between the human factor and marine accidents’ consequences. The paper is concluded with interesting insights and comments drafted through the aforementioned tasks.     

Scientific requirements for an abyssal benthic laboratory

For over thirty years man has studied “outer space” and installed satellites which watch the surface of the Earth. The great depths of the world ocean are, however, practically unknown and there is an urgent need to put abyssal benthic laboratories into “inner space” in order to study basic phenomena of interest to marine science and climatology as well as man's impact on the oceans.In view of the numerous problems related to global change, as a first step emphasis should first be on the role of the oceans and their inherent processes, which are the focus of such international programmes as the World Ocean Circulation Experiment (WOCE) and the Joint Global Ocean Flux Study (JGOFS). Multi-disciplinary registration of key events at selected key sites investigating the variability in time and space are of the utmost importance. The same methods and techniques must be used for the study of human impacts on the deep oceans caused by mining of metalliferous resources and by waste disposal as well as in basic studies. However, the investigation of the inner space of our planet has certain requirements. As long-term and large-scale investigations become more and more important, development of automized systems, largely independent from research vessels will be required. This will demand high capacities of energy for all technical functions as well as high storage capacities for data and samples. As a consequence the needs for two different—although overlapping—functional approaches are defined for future deep-sea deployments.(A) A system for long-term registration of the natural variability and long-term monitoring of human impacts: (B) A system for short-term observations and short-time experimentations. This report summarizes their technological demands. The envisioned interdisciplinary technology should deliver information on physical, biological and geochemical processes and their variabilities in the deep oceans. The prospected systems need to have the ability for real time video observation, data transfer and experimental manipulation, as well as sensing and sampling facilities with large storage capacities for long-term deployments.Prospective costs of the described multipurpose abyssal benthic laboratory will presumably exceed the funds for deep-sea research of a single country. A joint European effort could solve this problem and help to manifest a leading role for European marine science in international deep-sea and global change research.     

Inertial waves in the Ibiza channel

Currentmeter data taken in the Ibiza Channel show the almost permanent presence of near-inertial motions below the mixed layer. They correspond to downwards progressing waves with a vertical group velocity of some m/day. The presence of the Balearic Front sensibly affects the propagation of these inertial waves. Although situations exist in which the passage of atmospheric fronts along the Channel is clearly the generating force of these near-inertial motions we find others in which the energy density in mid-depths is higher than in any other depth. These last situations are closely related to the arrival to the Channel of some of the different water masses which flow around there. A clear correspondence between the presence of relatively strong inertial waves and a noticeable vertical shear of the subinertial flow, evidenced by an averaged Richardson number, is also observed. In some circumstances, the vertical shear of the whole flow (inertial plus subinertial) is higher than the stability limit, that is, Ri < 0.25, favoring the braking of the internal waves. This could be a plausible cause of their decay and a reason to explain why they do not penetrate further than certain depths.     

The Nonlinear Behaviour of a MacPherson Strut Wheel Suspension

Three nonlinear models of a MacPherson strut wheel suspension have been studied. The nonlinearities considered are due to the nonlinear geometrical effects in the mechanism, the amplitude limitation due to the bumpstop, the progressive stiffness of the bumpstop and the different damping coefficients for the shock absorber in bump and rebound. The models have been derived according to physical parameter values of. the MacPherson strut wheel suspension of the car SAAB 9.000. The most suitable model was further studied with special attention to nonlinear phenomena. For harmonic forcing the system had phenomena such as multiple solutions and subharmonics. For some parameter values the solution was very sensitive to changes in the integration tolerances in the numerical integration routine. No chaotic steady state solutions were found for the parameter values studied.     

秦虹大桥大型支架体系设计施工技术

文章通过对秦虹大桥施工用支架体系的设计和施工经验介绍。尤其是支架体系中组合支架体系的运用和利用现有的制式器材实现支架体系快速施工的经验介绍，为类似工程提供了很好的借鉴和引导。     

大秦铁路开行2万t级重载列车对既有桥梁上部结构的影响

大秦铁路将开行2万t重载列车,简要分析开行2万t重载列车后,恒、活载的变化对桥梁上部结构,尤其是常用跨度简支梁的影响,并提出尚待进一步研究的问题。     

Four-wheel vehicle kinematic and geometric constraints for definition of tire slip angle

When considering vehicle safety, tires and all that they represent are a fundamental topic. Tire studies have received a considerable amount of attention from the research community because their improvement has a direct and strong impact on vehicle handling and braking. Within this eld of analysis lies an important behavioral feature: the tire slip angle, which is a consequence of lateral forces acting on the tire. This characteristic is predicted in some cases and evaluated experimentally in others. This paper addresses another way to assess the slip angle. We propose a mathematical model that describes a constraint linking the slip angle and steering angle that make a vehicle turn. We present a simplied kinematic model (based on the classic bicycle model) and a four-wheel model, which makes all of the angles involved compatible with each other. In our case, the match will be given by the determination of the turning radius. Two different scenarios, understeering and oversteering vehicles, were simulated, and the results and conclusions reached are presented herein.     

Port strategic planning: Canadian port reform

Recent port reform established major commercial ports as Canadian Port Authorities (CPAs) as federal non-profit, business corporations. Canadian port reform was aimed at allowing CPAs to compete effectively. Canada's major ports operate in an increasingly competitive business environment. To gain advantage over their competition, Canadian ports must develop business strategies dealing with their organizational cultures, institutional structures, operations, and facility provision. Developing appropriate strategies involves creating a strategic plan that considers external and internal port environments. This paper outlines the evolution of strategic planning and its applicability to Canadian ports. The initial literature review is followed by a brief review of Canadian port reform and an analysis of external and internal port environments. This analysis determines the resources available to exploit external opportunities and defend against threats, and considers the internal strengths and weaknesses of Canadian ports. A list of strategic issues facing Canadian ports and how the Canada Marine Act affected them is derived from the analysis.     

基于四轮轮边驱动电动车的路面附着系数估算方法

路面附着系数是影响车辆行驶安全性的重要因素,利用轮边驱动电动汽车驱动力矩可以对路面利用附着系数进行观测。当观测到μ-λ曲线接近于峰值点时,将该时刻的轮胎利用附着系数作为路面峰值附着系数,并根据识别的路面峰值附着系数进行驱动防滑控制。该方法能够有效防止轮胎滑转,提高车辆行驶稳定性。