高速公路项目的交通量预测方法探讨

从高速公路项目的自身特点出发,探讨了在建设项目工程可行性研究中,应用区域经济学分区理论,在区域社会经济发展预测的基础上,用四阶段法进行交通量预测的方法。     

业界老总支持旧船报废补贴

河北远洋运输集团董事局主席高彦明最近出面表态，力挺政府为淘汰旧船而推出的激励计划。作为国内航运业最受尊崇的老总之一，高提出，应该为老旧的远洋散货船提供同样的补贴。     

大型深水基础施工方案研究

介绍大型深水基础施工方案的研究,包括双壁钢吊箱围堰定位方案的比选、重型锚碇系统的设计和布置等。     

转移排队车辆控制尾气排放的应用实例

为了缓解苏格兰法夫（Fife）地区库珀（Cupar）镇的交通拥堵，减少关键区域的尾气排放，用S-Paramics模型进行测试。采取的措施是把排队车辆转移到道路宽阔且建筑物较矮的路段，使车辆尾气易于扩散。测试结果显示，该方法能显著减少关键区域的尾气排放量，而车辆行程时间基本保持不变。项目的评价标准不是基于传统的行程时间和车辆运营成本的节约，而是考虑了行人和当地商业的利益。     

国产化钢轨打磨列车的功率计算

钢轨打磨列车国产化过程中 ,整车功率的正确计算是设计阶段必须首先解决的主要问题。为此 ,本文专门针对钢轨打磨列车的工作特点 ,以铁路机车牵引计算方法为依据 ,结合打磨砂轮切削钢轨时的金属切削理论 ,总结出钢轨打磨列车功率计算方法。     

基底面积对地基刚度和阻尼的影响

本文通过强迫振动试验，研究了基底面积对地基劝力特性的影响，提出了确定大型动力机器基础地基刚度和阻尼的新方法。在分析地基的动力参数时，采用了考虑地基土参振作用的质－阻－弹力学模型。     

Multi-fidelity optimization of a high-speed foil-assisted semi-planing catamaran for low wake

The wakes of high-speed passenger-only ferries that operated through Rich Passage, on the Seattle-Bremerton ferry route, caused beach erosion and damage to habitat. A task was initiated to design a low-wake high-speed vessel using multi-fidelity CFD based design optimization by using low-fidelity potential flow solvers for initial global design optimization and by using URANS solvers for high-fidelity tuning of the optimized design. This simulation based design process involved a close collaboration between ship designers, and hydrodynamics and CFD specialists, whose collective expertise guided the evolution of the design based on both hydrodynamic and structural aspects. The initial hull shape optimization using potential flow code was carried out by blending three different initial concepts provided by the designers. Subsequently, URANS was used to evaluate the potential flow optimized hull and to further optimize the hull configuration parameters, namely, the centre-of-gravity, demihull spacing, foil location, foil angle and slenderness ratio at different displacement conditions. The URANS based configuration optimization also took into account the far field wakes’ energy spectrum with an objective of reducing the energetic, low frequency far field wakes which are associated with beach flattening on the mixed sand and gravel beaches. Calculation of the far field wake using URANS would require an unfeasibly large domain size; therefore, a Havelock code with a source distribution matching the URANS calculated near field wave elevation was used to propagate the wakes into the far field. The end result of the optimization was a design with significantly reduced far field wake, which is currently being built for experimental testing.     

大众手工作业——试架大众辉腾

每年大众出品的汽车数以万计,但其中只有极少的数量由资深技师们手工打造。这些手工产品只为那些喜欢低调的大佬们准备,精细的工艺,宽敞的空间,以及高科技的配置让这些“手工作业”成为大众的招牌,它们有一个名字——辉腾。     

Revisiting the notion of induced traffic through a matched-pairs study

In investigating the question of the existence of "induced demand" in connection with highway expansion projects, Hansen et al. (1993) studied eighteen California state highway segments whose capacities had been improved in the early 1970s. For the present study, these segments were paired with control segments that matched the improved segments to unimproved ones with regard to facility type, region, approximate size, and initial volumes and congestion levels. Taking annual data for average daily traffic (ADT) and design-hour-traffic-to-capacity (DTC) ratios during the 21 years 1976–1996, three approaches were used to compare growth rates between the improved and unimproved segments: overall growth comparisons for the matched pairs, repeated measures analysis, and analysis of matched mean profiles. We found the growth rates between the two types of segments to be statistically and practically indistinguishable, suggesting that the capacity expansions, in and of themselves, had a negligible effect on traffic growth over the period studied. Reasons for the differences between these results and those of aggregate cross-sectional models finding a significant induced demand effect are discussed. Our analyses suggest that the aggregate models may overestimate induced traffic due to the attribution of at least a fraction of the observed traffic growth to "induced demand" rather than to some of the confounding factors which were not controlled for in such studies. At the same time, it is noted that the traffic induced by capacity expansion may in certain circumstances be larger than that observed in the present study, with the effect of new highway construction on traffic growth being a prime candidate for scrutiny in this regard. The results of this study nonetheless suggest that, for existing facilities, the size of the induced-traffic effect that can be attributed to capacity enhancements may be sufficiently small that its detection in a case-control study would be difficult, if not impossible, without a substantially larger sample size.     

闭口薄壁杆件翘曲函数的研究

本文分析了闭口薄壁杆件的扭转翘曲和畸变翘曲之间的关系,给出用一个或两个函 数来表达这两种翘曲的判别条件。文中还着重讨论了扭转和畸变翘曲函数分别与扭 转角和崎变角之间的关系,指出不能用后两者的一阶导函数来代替前两者.为正确选 用翘曲函数提供了理论依据。