不同因素对半柔性路面材料抗裂性能的影响研究

半柔性材料作为一种新型的路面材料,兼具水泥路面强度高和沥青路面柔性好的优点。为了研究不同因素对半柔性材料的抗裂性能的影响,文章通过大量室内试验,分析了三种集料与三种沥青对半柔性材料低温和疲劳性能的影响,试验结果表明,采用玄武岩集料和高粘改性沥青的效果最好,可为半柔性材料在公路路面建设中的应用提供参考。     

长寿命路面设计与应用探讨

针对目前国内半刚性基层沥青路面普遍出现的早损现象,吸收国外先进的设计理念,合理考虑超载影响,结合高速公路路面维修实例,对柔性路面基层进行了有益的探讨,寻找适宜的路面结构,延长沥青路面全寿命面使用周期.     

高性能半柔性路面在改造工程中的应用研究

文章通过进行母体沥青混合料和水泥砂浆的配合比设计及试验路段的行车观测,评价高性能半柔性路面材料的力学性能和路用性能,为半柔性路面的设计和施工提供了依据,并指出高性能半柔性复合面层将有更新的发展,符合重载交通路用性能要求。     

半柔性路面在广西沥青路面养护工程中的应用

文章对传统AC-13路面、OGFC-13路面与半柔性SFAC-13路面进行路用性能对比分析,分析半柔性SFAC-13路面在力学性能、抗压强度、疲劳寿命、抗压回弹模量等方面的优势,继而比较出适用于广西高速公路养护的路面,以有效提升养护路面使用性能。     

浅谈沥青路面的裂缝与预防

沥青路面在使用期开裂是世界各国普遍存在的问题,且不论其基层是柔性的还是半刚性的.路面裂缝的危害在于从裂缝中不断进入水分,使基层甚至路基软化,导致路面承载力下降,产生唧浆、台阶、网裂等病害,从而加速路面破坏.     

重载交通高速公路ATB基层沥青路面设计与施工

柔性基层沥青路面在我国是一种新型路面结构。文章结合工程实例,介绍柔性基层沥青路面结构方案及重载交通高速公路ATB基层沥青路面设计与施工工艺,为此类工程提供参考。     

路面结构层厚度对级配碎石应力状态的影响分析

级配碎石材料作为柔性材料的一种,在组合式基层以及半刚性基层沥青路面补强结构中大量应用,具有良好抵抗反射裂缝、排水的作用。在路面结构层中具有明显的应力依赖性,与其所处层位、各结构层厚度与模量等均直接相关。在路面结构设计中通常仅对基本参数取值而忽略其应力依赖性,特别是在补强路面结构中,由于受高程限制,补强层厚度对其力学性能影响尤为重要,主要对补强结构设计中各结构层厚度对级配碎石应力状态影响进行分析。     

公路沥青路面裂缝的预防和处理

阐述公路沥青路面裂缝的形成、危害及裂缝的种类、产生原因,提出对裂缝的预防和处理措施.由于半刚性材料的抗变形能力低,在温度、湿度变化时容易产生裂缝等缺点,当沥青面层较薄时易形成反射裂缝,沥青路面本身也容易产生低温裂缝,沥青路面一旦产生裂缝,有可能导致路面结构性破坏,路面的使用功能大大降低.     

柔性基层在路面病害治理中的应用

通过对半刚性基层和柔性基层特点进行对比分析,叙述了柔性基层材料在半刚性基层沥青路面裂缝治理中的可行性。     

基于沥青路面半刚性结构的破损研究及评价

半刚性基层路面的性能评价是对路面养护、铺装、维护的有力依据。然而依据现行公路技术评价体系对西部高速公路进行评价时,路面状况指数经常超限。针对这一问题,文章基于国内外沥青路面破损及评价研究现状,从计算弯沉值、路面结构强度指数PSSI、路面车辙状况RDI等方面,研究了半刚性基层沥青路面结构破损状况的计算方法,并结合工程实例进行了应用分析,为沥青路面半刚性结构破损评价提供理论依据。     

Analysis of factors affecting the choice of route of pedestrians

Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD).

An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip.

It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links.     

实现多组态计量软件集中监控的可行性分析

天然气自动计量系统有多种组态软件,由于软件的不相通性,造成了计量系统数据采集的通用性差、数据传输与入库的时效性差、数据利用的可靠性低.结合各组态软件的实际情况,从设计上充分利用Oracle大数据处理能力以及Partition(分区表)的特性,实现历史数据的存储,应用WebService与COM+数据访问组件提供多层数据访问架构,采用OPC与DDE工业数据交换协议,实现了各站场计量数据的实时上传,为连续数据采集和实时监控提供了可能,节约了改造成本.     

注汽管道承压能力评估和实物试验验证

基于失效评估图技术对某注汽管道进行了承压能力评价,给出了管线在不同腐蚀壁厚情况下的极限承压能力和极限裂纹尺寸。并利用实物爆破试验验证了评价方法的安全性和有效性,通过对爆破断口进行宏观和微观分析,发现管段的开裂属于脆性开裂。     

Non-parametric analyses of efficiency of airports

This paper estimates the efficiencies and productivity changes of 12 international airports in the Asia-Pacific region based on data from 1998 to 2006. We apply stochastic frontier analysis (SFA) to compute efficiency estimates and use the Malmquist productivity index (MPI) to analyze productivity changes. We use the SFA model with a translog-type production function after testing the statistical hypotheses. According to the results of the SFA hypothesis tests, airports have experienced a technological regression; the deviations from the efficiency frontier are caused more by technical inefficiency than random noise. However, the inefficiency was found to decrease. The MPI reveals a declining trend resulting more from technological change than from efficiency change, with a decrease in inefficiency. Taken together, both the hypothesis tests and the MPI not only provide consistent conclusions, but also suggest that airports should concentrate on technological progress.     

波纹管应力分析研究进展

评述了波纹管应力理论研究方法的进展情况，围绕解析法、工程近似法和数值法，对波纹管理论研究中的一些主要成果作了较详细的回顾和总结，对各种研究方法作出了评价，展望了亟待解决的一些问题。     

输油管道中原油乳状液的流变性研究

原油乳状液的流变性是原油开采后在管道中输送的重要研究方面,为了更好地研究这一性质,采用电动搅拌机、偏光显微镜以及流变仪等仪器来测定不同含水率的原油乳状液在不同条件下的黏度,观测不同含水率的原油乳状液在偏光显微镜下的形态。并且分别对原油乳状液的黏度与含水率之间的关系以及与剪切速率之间的关系进行研究,初步确定了所测区块原油乳状液的转相点以及该区块原油乳状液的流变特性,为生产中的油气集输提供了理论依据。     

埋地管道防腐保温层失效评价

明确埋地管道防腐保温层的技术评价标准,对埋地钢质管道的安全运行,延长管道使用寿命具有重要意义。为了对埋地管道防腐保温层做出有效评价,从间接检测与开挖检测2个方面,结合现场检测数据,提出了基于防腐保温层的电流衰减率、绝缘电阻率、质量状况与厚度的分级评价标准及基于4种评价指标的综合评判方法。工程实践表明,该评价标准对防腐保温层是否存在失效能做出有效判断。     

城市轨道交通杂散电流监测系统概述

介绍了城市轨道交通工程中杂散电流不同的监测系统的构成,分析了集中式、分散式和智能型等监测系统的配置和功能,以及智能型实时在线监测系统的重要意义,为轨道交通工程杂散电流监测系统的选择与应用提供参考。     

Preliminary results of an analysis of areas of influence in Shanghai

The main deficiency of most current modeling approaches to transportation can be identified as neglect of the integration of existing geographical knowledge in regard to the ex ante transport/land use modeling approaches, with its focus on territorial dynamics and theory development. This paper addresses this aspect of the problem by introducing a theoretical and methodological framework for the analysis of the interrelationship between land uses. The analysis attempts to determine to what extent the functional land use in a city can be considered an ordered pattern. The order sought does not rely on purely spatial configurations, but on the correlation of transportation and land use. The first section of this paper focuses on theoretical considerations. It stresses the fact that conventional approaches do not apply in the present context. It then suggests an alternative based on areas of influence and measured in terms of level of attractance of land uses. The second describes a procedure based on this alternative following the remarkable contribution of Hanjoul, Beguin and Thill. An application of this procedure to the analysis of Shanghai is then examined. Finally, an evaluation of the strategies for optimizing the interrelationship between land uses is presented. The paper concludes with a possible research agenda.     

Direct analysis of the perceived importance of attributes of reliability of travel modes in urban travel

Reliability of travel modes was found to be the most important characteristic of transportation systems in several attitudinal investigations of individual travel behavior. This paper represents the first part of a research effort aimed at gaining a better understanding of the characteristics of reliability of transportation modes in urban travel. In this research, reliability characteristics are identified; their importance relative to each other is assessed, and an insight into possible structure of an objective reliability index is discussed. The research is based on perceived values of reliability, which were identified through a large attitudinal survey conducted in the Chicago metropolitan area.