地下工程排水管管材性能价格分析

地下工程排水管材中,钢筋混凝土管和塑料管在性能和价格方面差异比较大。分析、比较了钢筋混凝土管、高密度聚乙烯(HDPE)双壁缠绕管、玻璃纤维增强塑料夹砂管、离心浇铸聚酯高强度夹砂复合玻璃钢管等4种管材的性能和价格。介绍了不同排水管管材在工程中的选择和应用。     

国产长输管道焊接施工装备研究

近年来,长输油气管道焊接施工装备技术快速发展,大量新型管道施工装备投入管道工程现场应用,比如管道全位置自动焊机、管道管端坡口机、管道内环缝自动焊机已被分别用于管口焊接、坡口加工、管口组对。在大厚壁、高钢级、大口径管道施工中,这些设备既提高了管道施工效率,也提高了管口的焊接质量。根据实际应用情况,阐述了前述设备的结构、性能和其他技术特点,以使相关技术人员对国产管道施工装备有进一步的认识。     

大口径长距离顶管工程注浆碱摩技术

大口径长距离顶管施工顶进推力过大量困扰顶管施工多年的技术难题,靠提高顶管管材的抗压强度,加固顶管工作坑及后背等方法不仅不经济,还受到技术方面因素的制约,注浆减摩作为一门新技术,在顶管工程中应用越来越普及,本文对注浆减磨原理,注浆材料的性质及注浆工艺进行了较大为系统的阐述,对于顶管工程的施工具有积极的参考价值。     

矩形顶管施工管线保护技术

上海市轨道交通4号线浦东南路车站的1,2号出入口采用矩形顶管法施工,该工程的接收井宽度小紧贴管线、项管离大口径管线极近、施工难度很高。介绍为保护管线而采取的顸管工作井、接收井的土体加固以及洞口加固等技术措施。     

新型管材—离心浇铸玻璃钢管

介绍了一种以聚酯树脂和玻璃纤维为原料，采用离心浇铸成型的新型管材－玻璃钢管的特点，结构及制造方法。     

大口径管道下向焊接

大口径管下向焊接是管道建设中的重要环节 ,有效控制焊接操作要点及焊接过程中应注意的事项是提高焊接质量的有效途径。着重介绍了在大口径管道焊接施工实践中总结的操作要领和焊接施工的经验     

大口径钢质管道内减阻涂层涂敷施工综述

在大口径长输天燃气管线上采用内涂层减阻技术，以达到降低管线摩阻、增加管输量、降低管线运行综合成本的目的，在我国首次应用于西气东输工程。根据实际施工经验，本文详细阐述了内减阻涂层的施工工艺流程，介绍了内涂敷设备和内涂敷质量控制，对内涂层的涂敷施工有一定的参考价值。     

大口径钢质管道内减阻涂层涂敷施工综述

在大口径长输天然气管线上采用内涂层减阻技术，以达到降低管线摩阻、增加管输量、降低管线运行综合成本的目的，在我国首次应用于西气东输工程。根据实际施工经验，本文详细阐述了内减阻涂层的施工工艺流程，介绍了内涂敷设备和内涂敷质量控制，对内涂层的涂敷施工有一定的参考价值。     

国产X52C连续管线管性能及其应用

为了促进国产连续管线管在油田的推广应用,对国产X52C连续管线管的管材性能和应用优势进行了分析.结果表明：管材各项性能指标满足并优于API Spec 5LCP《连续管线管》标准要求,且具有良好的耐蚀性.国产X52C连续管线管作为集输管线管在青海油田涩北气田得到了成功应用,与常规20#无缝钢管相比,作业时间缩减了75％,并降低了施工费用,提高了管线运行的可靠性.连续管线管具有良好的技术和经济优势,将在陆地及海洋集输管线上得到广泛应用.     

新型防腐管材在油田集输工程中的应用

由于原油及所含污水对金属管道的腐蚀性 ,尤其是在高含水地区 ,经过防腐处理的沥青管线1a内就会出现穿孔 ,平均 2～ 3a就要更换 ,给油田造成了巨大的损失 ,金属管道的腐蚀严重影响了油田生产的正常运行。选择具有代表性的玻璃钢增强复合管、钢塑增强复合管、环氧粉末内涂管、高密度聚乙烯穿插管等新型防腐管材 ,就这些管材的结构、特点及在油田地面工程的应用进行介绍和对比分析 ,说明其适用性     

Assessment of policies and detection of unintended effects: Guiding principles for the consideration of methods and tools in policy-packaging

Single policies or entire policy packages are often assessed using different methods aiming at a quantification of effects as well as the detection of undesired outcomes. The knowledge of potential impacts is essential to take informed policy actions. Hence, there is a constant need for efficient assessment approaches to support policy decision-making. A broad range of such assessment methods is used in policymaking. Some of them are using quantitative data; others are characterized by qualitative information, observations or opinions. Practical experiences with transport policy prove that these methods all have their pros and cons, but none of them are able to detect the full range of effects. This leads to important questions this article deals with, such as what are the strengths and limitations of the different tools and methods for assessing impacts, and how should different approaches be integrated into the policymaking processes?We analyze the ability of assessment methods to detect different kinds of intended and unintended effects, and introduce the concepts of structurally open (mainly qualitative) and structurally closed (mainly quantitative) methods. It is argued that these concepts support making the pros and cons of the tools and methods more explicit and, thus, allow integrating the different tools and methods into the process of policy packaging. Based on a policy package example, we provide practical recommendations on how to integrate different assessment methods adequately and show that both quantitative and qualitative tools should be used in different phases of the process. The main recommendation is to alternate the application of assessment methods with structurally open methods used in the beginning and the end of the policymaking process and applying structurally closed methods in between.     

On finite sample performance of confidence intervals methods for willingness to pay measures

This paper systematically compares finite sample performances of methods to build confidence intervals for willingness to pay measures in a choice modeling context. It contributes to the field by also considering methods developed in other research fields. Various scenarios are evaluated under an extensive Monte Carlo study. Results show that the commonly used Delta method, producing symmetric intervals around the point estimate, often fails to account for skewness in the estimated willingness to pay distribution. Both the Fieller method and the likelihood ratio test inversion method produce more realistic confidence intervals for small samples. Some bootstrap methods also perform reasonably well, in terms of effective coverage. Finally, empirical data are used to illustrate an application of the methods considered.     

Methods of analysis for vehicle soak time data

Vehicle soak time, the duration of time a vehicle’s engine is at rest prior to being started, and its distribution function are important transportation activity data inputs for mobile emissions inventory estimation due to their impacts on vehicle start and evaporative emissions. This paper provides vehicle emission researchers with an overview of statistical analysis methods relevant to analyzing vehicle soak time data. Many of these methods are already in use in emissions research and have appeared in the literature. These methods are reviewed and further details regarding the implementation and interpretation of these methods are provided. Statistical methods relevant to the analysis of soak time data that have yet to appear in the emissions literature, including kernel density estimation and generalized linear models, are also introduced. Advantages and disadvantages of the methods are compared and theoretical justification is provided. Issues of correlated observations and censored data are discussed. General guidelines for the analysis of soak time data, such as stratification by start type and geographical region, are established. Finally, a subset of the statistical methods discussed is used to analyze the US Environmental Protection Agency’s 3-city data.     

The Value of a Statistical Life in a Road Safety Context — A Review of the Current Literature

Abstract

This paper summarizes the state-of-the-art for assessing the value of a statistical life (VSL) as a component of the costs of road accidents. It focuses on the most popular approaches for assessing the VSL, with respect to its theoretical foundations, current state-of-research and empirical evidence. Our paper also provides a first (to our knowledge) compendium of results for the VSL based on Stated Choice (SC) methods. Among the analysed alternatives, the willingness-to-pay (WTP) appears to be the leading approach for assessing the VSL and the SC methods represent the current state-of-the-art for determining the WTP for non-market goods. We conclude that the SC approach overcomes some of the most important shortcomings of the alternative approaches and offers a significant flexibility that can be used to address its own limitations. We also identify a significant need for research, as a gap between the methods employed in research (SC methods) and the state-of-the-practice (other methods) has emerged.     

岩爆灾害研究与进展

为阐明岩爆机理,减少岩爆灾害,对岩爆的定义、分类、研究方法、特征、形成条件、预测方法及防治措施进行了系统的阐述。在前人工作的基础上,结合国内外已有的工程实例,对岩爆的时空特征和发生部位的岩性特征进行了剖析,对已有的岩爆研究方法和预测方法进行了合理分类和简要介绍,指出了部分研究方法的不足之处和预测工作的发展趋势。综合现有研究表明:岩爆分类采用的标准各有不同,其研究方法还具有改进的空间;适用于大部分工程的岩爆预测方法仍在探索和完善中;有效的岩爆防治措施有待进一步研究和优化。     

天然气管道氮气置换技术研究

针对新建或需要检修的天然气管道,介绍了其投产前用氮气置换空气的几种方法,阐述了它们的工作原理与实施步骤,对比分析了它们的优缺点,从而得出各种方法的适用场合,同时,探讨并总结了氮气置换过程中注氮温度、注氮压力、注氮点、注氮量、天然气推进速度等操作参数的确定方法,得出了相应的结论,为确保天然气管道的安全投产奠定了基础.针对置换工艺与操作参数最优化的确定方法,提出了意见和建议.     

Competing risks analysis on traffic accident duration time

Different clearance methods in traffic accident management lead to varied duration distributions. Apart from investigating the influence of various factors associated with accidents on the duration of such accidents using different clearance methods, this study also examines the cumulative incidence probability. We used traffic accident data obtained for 12 months from the Fourth Ring Expressway main line in Beijing to develop a subdistribution hazard regression model, which can assess the risk factors of two clearance methods. The regression results show that the different factors have statistically significant effects on the duration of two accident groups with different clearance methods; furthermore, opposite effects occur even for some factors that have a strong effect on both accident groups. For example, an accident involving a taxi extends the duration time with clearance method 1; in comparison, the accident is shorter with clearance method 2. The predicted cumulative incidence curves of the two types of clearance methods are shown as examples, with stratification based on the influence factors (taxi involved, season). Finally, the Gray test of the cumulative incidence functions and the log‐rank test of the Kaplan–Meier estimates of the survival functions are compared, in order to demonstrate the importance of using proper methods for analyses. Copyright © 2014 John Wiley & Sons, Ltd.     

含缺陷压力管道安全评定方法研究的现状与发展

含缺陷压力管道安全评定的方法较多,主要有极限载荷控制的塑性失效准则、断裂力学J积分的评定方法、英国R6双判据准则评定方法、美国ASME规范评定方法、参数不确定性缺陷的安全评定方法等.文章对这些方法加以简要的概括和评述,并分析了有些方法之间的区别与联系,同时指出工程化、可靠性和智能化是当前含缺陷压力管道安全评定方法的发展趋向.     

Appraisal of investments in European nodal centres for goods – freight villages: A comparative analysis

The paper presents and analyses appraisal methods used for the assessment of potential investments in Nodal Centers for Goods (also called Freight Villages), which constitute an essential element of the Trans-European Network for Intermodal Transport. A methodological procedure is applied to identify the underlying factors that influence the choice of an appraisal method, without assessing or comparing the appraisal methods themselves. Following this procedure, issues addressed by the methods are grouped into three broad dimensions and with the use of non-parametric statistical tests, existing relationships are identified between nodal centres' characteristics, the appraisal methods, as well as the actors involved in the decision process. On applying the above procedure to European Nodal Centres for goods, it is found that the choice of appraisal method and the decision criteria for the investment are linked primarily to the nodal centre's size, catchment area, and the support or absence of political approval for the investment. The results of the analysis can be particularly useful at the policy making level, serving as non-formal "qualitative guidelines" to identify the appraisal method to be applied, as well as the options and impacts to be considered. This revised version was published online in June 2006 with corrections to the Cover Date.     

Comparative analysis of transit assignment: evidence from urban railway system in the Tokyo Metropolitan Area

This paper empirically compares the performance of six traffic assignment methods using the same empirical dataset of route choice. Multinomial logit (MNL), structured multinomial probit (SMNP), user equilibrium (UE), logit-based stochastic user equilibrium (SUE), probit-based SUE, and all-or-nothing (AON) assignment methods are applied to the comparative analysis. The investigated methods include those with three types of error components in their cost functions and two types of flow dependencies. Four methods of generating the route choice set are also compared for use as stochastic traffic assignment methods. The revealed preference data of urban rail route choice in the Tokyo Metropolitan Area are used for the case analysis. The empirical case analysis shows that probit-based SUE provides the best accuracy but requires the longest computation time. It also shows that the heuristics used to generate the choice set influence the method’s accuracy, while the incorporation of route commonality and in-vehicle congestion significantly improves its accuracy. Finally, the implications for practical rail planning are discussed on the basis of the analysis results.