A regional railroad network optimization model for coal transportation

A regional railroad network is presented to evaluate the system's response to increased coal traffic. An optimal, multimodal, coal-shipping pattern is developed for the study region to minimize total costs and to efficiently use the existing network. A two-stage, general model allocates resources among demands and then assigns flows to the network according to efficiency criteria. The model is sufficiently general to permit modification for specific needs, assumptions and data. Government agencies and industries can apply the model in resource allocation decisions and transportation policy analysis.     

Methodology for the accuracy improvement of FEM beam type T-junctions of buses and coaches structures

The analysis of structures with finite elements methods (FEM) represents a widely spread technique. For large tubular structures similar to the buses and coaches upper structures, beam type elements are utilized due to the fact that these elements provide satisfactory results at relatively reduced computational performances. However the beam type elements have a main disadvantage determined by the fact that the modeled joints have an infinite rigid behavior. This shortcoming determines a stiffer behavior of the modeled structures which translates into an error source for the structural simulations (up to 45%). To overcome this problem, a simple methodology was conceived and an alternative optimized equivalent beam model obtained. The methodology studies the behavioral characteristics of beam modeled T-junctions determining their limitations and comparing them to equivalent T-junctions modeled with shell and volume elements. This way an improved Tjunction has been obtained, in which the behavioral error was reduced to less than 5%. Furthermore the FEM obtained results were validated with real T-junctions.     

安康市汉江景观桥设计方案研究

安康依汉江而建，桥位处周边建筑具有重要的历史文化意义，且桥位两边连接安康重要的街道和火车站。汉江景观桥在桥位走向、桥型选择与周边历史文化的契合度、景观桥与汉江两边道路的衔接等方面是重点研究的课题，从设计思路、功能定位、桥位比较、桥型方案、造价等对安康市汉江景观桥设计方案进行了研究。     

抗拔桩和压顶梁对明挖地铁车站内力影响分析

在高地下水位地区修建地铁车站,往往存在抗浮问题。抗浮问题处理得当与否直接关系着地铁车站正常使用期间的可靠度。而采用不同抗浮措施会对结构内力产生不同的影响,为研究这种影响并希望从结构受力角度对车站抗浮提出一定的建议,结合一个明挖地铁车站实例,针对目前最常见的2种抗浮措施——压顶梁和抗拔桩进行数值计算,发现抗拔桩具有改善结构受力的作用,在结构跨度较大时应采用抗拔桩或者抗拔桩与压顶梁联合抗浮的措施,在结构跨度较小时,可优先考虑压顶梁抗浮。     

Review of flywheel based internal combustion engine hybrid vehicles

Hybrid vehicles of different configurations and utilizing different energy storage systems have existed in development for many decades and more recently in limited production. They can be grouped as parallel, series or complex hybrids. Another classification is micro, mild and full hybrids which makes the distinction on the basis of functionality. The common energy storage systems in hybrid vehicles are batteries, supercapacitors and high speed flywheels. This paper aims to review a specific type of hybrid vehicle which involves the internal combustion engine (ICE) as the prime mover and the high speed flywheel as an energy storage device. Such hybrids are now attracting considerable interest given their potential for low cost. It is hence timely to produce a review of research and development in this subject. The flywheel is coupled to the drive line with a continuous variable transmission (CVT). The CVT can be of various types such as electrical, hydraulic or mechanical but usually in this case it is a non-electrical one. Different configurations are possible and the paper provides a timeline of the development of such powertrains with various examples. These types of hybrid vehicles have existed as prototypes for many decades and the authors believe that their development has reached levels where they can be considered serious contenders for production vehicles.     

并行工程在船舶设计与建造中的应用

在分析并行工程特点的基础上,提出了并行工程下的船舶设计建造系统结构,讨论了其实现的关键技术.给出基于DFM/DFA的CAD/CAM/CAE集成示例.     

引导接车编码电路存在的问题及改进措施

《技规》第285条规定：凡进站、接车进路信号机不能使用,或在双线区段由反方向开来列车而无进站信号机时,应使用引导信号或派引导人员接车。引导接车时,列车以不超过20 km/h速度进站，并做好随时停车的准备。 1 问题描述     

Network representation,continuum approximations and a solution to the spatial aggregation problem of traffic assignment

This paper complements the preceding one, which showed how one could modify equilibrium traffic assignment algorithms for networks with many centroids. In this one it is shown how one can substitute centroids by zones with continuous population densities. The technique, which is mathematically guaranteed to approximate a flow pattern in accordance with Wardrop's user equilibrium criterion, requires some geometrical calculations which can be handled off-line. With the suggested approach, it is possible to represent the spatial distribution of trip ends more realistically and this allows traffic assignment models to capture the effects of short and intrazonal trips in a way previously impossible. The method is shown to be computationally feasible.     

转型发展:CCS只争朝夕

十年前,中国船级社(CCS)紧紧把握船检体制变革带来的发展机遇和发展动力,站在服务国家相关行业发展的全局高度,重视战略思考和战略布局,以前瞻性的目光及时捕捉全球航运安全要求不断提升、船舶大型化和技术附加值提升、我国造船产能快速提升、我国自有船队不断发展等趋势,通过"局社分开"后的前期转型,有力地促进了跨越发展。今天,围绕落实中央关于加快转变经济方式的战略部署以及全国交通运输工作会议的要求,2月27日,CCS总裁李科浚在2010年工作会议上,对CCS加快转型发展作出了详细部署,再次拉开了转型发展的大幕。