亚临界淬火对LZ50钢车轴性能的影响

对LZ50钢车轴亚临界淬火前后的力学性能、晶粒度以及车轴表面残余应力的变化进行了试验,分析了亚临界淬火对LZ50钢车轴拉伸性能和表面质量的影响。试验表明,亚临界淬火对车轴拉伸性能无明显影响,然而车轴表面的残余应力变化很大,可由拉应力改变为压应力,而且通过优化加工工艺,表面压应力的增幅会更大,说明亚临界淬火能有效提高车轴的疲劳寿命。     

沥青混凝土摊铺机熨平板与热沥青混合料相互作用的动力学模型

在介绍了沥青混凝土摊铺机熨平板与热沥青混合料相互作用的特点后，叙述了热沥青混合料的流变特性，并给出了流变模型，就此得出了熨平板与沥青混合料相互作用的三种动力学模型。     

Walking accessibility and property prices

Walking is an imperative travel mode, especially for short trips. Walking accessibility, which is defined as the ease of reaching essential destinations in the walk-in catchment area, may affect property prices because residents are more likely to be willing to pay for this attribute. In addition, different categories of public services may have varied influencing directions and magnitude. These two hypotheses are tested in this study. Taking Xiamen, China as a case study, we estimate the cumulative opportunities of public services on foot and develop a set of hedonic pricing models (more specifically, two pre-specified ordinary least squares models, four Box-Cox transformed models, and two spatial econometric models) to estimate, whether and to what extent, walking accessibility contributes to price premiums (or discounts). Using a database of 22,586 second-hand residential properties in 358 multi- or high-storey residential complexes, we find that (1) walking accessibility to public services contributes to the variations in housing prices and plays a role in determining housing prices; (2) different categories of services have vastly divergent, even opposite, influencing impacts; and (3) walking accessibility to primary schools, commercial centers, and sports and cultural centers have positive effects on house prices whereas walking accessibility to comprehensive hospitals adversely affects housing prices. Methodologically, we confirm that spatial econometric methods improve estimation accuracy and have more explanatory power relative to the standard non-spatial models. Robustness check analysis further guarantees the plausibility of this study.     

Property Evolution of Sulphoaluminate Grouting Material under Pressure Circulation北大核心CSCD

Water-sealed underground oil tank projects are quite different from traditional underground projects since the water-sealing conditions are very strict and the difficulties caused by the geological specificity, structural specificity and construction specificity are key factors affecting the project. In light of the significant early initial setting time and rapid temperature increase of sulphoaluminate cement-based grouting material for a large domestic water-sealed underground oil tank with pressurized cyclic grouting, a laboratory grouting simulation is conducted. It is found that the properties of the sulphoaluminate cement-based grouting material are quite different under different pressure cycles, the hydration exothermic peak time gets shorter with an increase of circulation time, the compressive strength decreases with an increase of circulation time, and the longer the circulation time the more obvious the de-crease of compressive strength. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Resolving the property right of transportation emissions through public–private partnerships

The application of public–private partnerships (P3’s) in the transportation sector has grown in popularity worldwide. Despite this important shift in the provision of transportation service, there are clear gaps in knowledge about the impacts of P3 projects, especially on emissions from transportation systems as a whole. Not only should policy makers evaluate the emissions impacts from P3 projects, but they should also think about innovative models that address or charge for emissions into P3 contracts. This addition to P3 contracts could provide a new solution to the long-existing property right paradox: who owns (is responsible for) emissions from transportation systems? This study attempts to fill the research gap by analyzing these innovative models. Using the road network of Fresno, California, as our case study, we offer a number of interesting insights for policy makers. First, average peak emissions costs range from 1.37 cents per mile (the do-nothing case) to 1.20 cents per mile (profit-maximizing cases) per vehicle. Although emissions costs from the P3 projects are lowest for the profit-maximizing cases, the system-wide emissions costs of these cases are highest because of spillover effects. Second, charging project owners for the emissions costs of P3 projects is not an effective way to reduce emissions or the total costs of travel, especially on a VMT basis. Instead, the public sector should implement emissions-included social cost-based price ceilings. When employing these limits, project owners could still be charged for the emissions costs. Finally, using total travel time as the only objective function for evaluating P3 projects can be misleading. Several P3 projects have shown better outcomes using total travel cost with the inclusion of emissions and fuel consumption costs, instead of using total travel time as the only objective function.     

双质量飞轮式扭振减振器

现代汽车广泛采用的是离合器从动盘式扭振减器，而双质量飞轮式扭振器则是近年来发展起来的一种更为有效的新型扭振减振器。本比较了了双质量飞轮式扭振减器和离合器从动盘式扭振减器的结构、性能及优缺点。     

论SBR改性沥青在辽北地区的应用

对SBR改性沥青的性能及经济性与其它种类沥青结合料进行了比对,分析后认为SBR改性沥青低温性能良好,价格优势明显,适于在辽北地区推广应用。     

香港“城铁一体化”开发模式对城际轨道交通可持续发展的启示

当前国内城际轨道交通的发展对以轨道交通为导向的城市综合开发提出更高的要求,针对性剖析香港铁路发展历程和成功经验,结合相关数据分析,研究"城铁一体化"综合开发模式对城际轨道交通可持续发展的作用和意义,对该模式下的财务、政策和技术层面的问题进行探讨,提出"城铁一体化"开发须在政策层面制定相应的"权益流程",实施开发建设的集约化;在运营层面体现"共赢"原则,构建"轨道交通运营+效益返还"机制;针对城市各区域发展不同步的特点,在一体化建设中采用灵活的预留机制满足分期建设的需求,最终实现轨道交通的可持续发展。     

地铁车辆基地上盖物业开发设计探讨

车辆基地的上盖物业开发在地铁建设中越来越受到重视,其设计和建设中所存在的问题急需总结并逐渐形成成熟的规定。通过某城市已建成运营的带上盖物业开发车辆基地的设计实例,总结上盖物业开发车辆基地设计特点及其在通风、排水、开发平台高程及实施接口预留等方面存在的问题。提出带上盖物业开发车辆基地设计中在投资决策、设计界面、消防及实施接口等方面的要求,为后续带上盖物业开发车辆基地设计提供参考。     

Environmental innovation and the role of stakeholder collaboration in West Coast port gateways

The paper explores the role of stakeholder collaboration in the adoption of innovations as part of the environmental and sustainability agenda of port gateways. We do this through a comparative assessment of the port of Vancouver, British Columbia, and the twin ports of Los Angeles and Long Beach, California. An inductive research approach is used to identify and assess the initiation and implementation process behind exemplary innovations. Innovation includes new technologies and processes for handling and moving cargo, mechanisms for planning and policy making, as well as financing, implementing, upgrading, managing and operating infrastructure systems. A relatively new arena for competition on the basis of innovation concerns environmental performance. The conceptual framework and empirical evidence suggest that while there may be intense demand for and supply of innovation in port gateways, the complex dynamics of the logistics chain are such that successful innovation requires conscious involvement and collaboration of stakeholders.