高压天然气集输管道除砂试验研究

研究了高压天然气管道除砂器的结构参数和流动参数对分离效果的影响,发现试验用分离器的高效流量调节比为10:1;叶片入口角变大有利于除砂效率的提高;出口角变小,可提高除砂效率;分离器能有效分离粒径大于40μm的砂粒,其除砂效率η>92%。     

在线旋流除砂工艺在渤海油田的应用

为解决渤海油田的井口出砂问题,基于旋流分离技术,提出了一种新型在线除砂工艺,通过6条工艺管线配合除砂设备实现了砂的脱出与处理。在现场调试过程中发现运行不稳定和旋流管内壁黏砂堵塞情况,改进了技术和操作流程,经过3次调试,80μm以上粒径的砂脱除效率达到100%,设备及工艺应用效果良好。该除砂设备及工艺在渤海油田的应用可以给海上油田的固液分离项目提供技术支持和经验。     

高压管线快速脱离装置设计

在海洋石油压裂增产作业中,作业船上的压裂系统通过高压软管与平台井口连接。在危险海况、平台发生险情时,作业船需要迅速与平台分离,而高压管道的分离拆卸需要人工近距离操作,分离缓慢,会导致管道、设备被外力损坏。针对这种状况,设计了高压管线快速脱离装置,该装置在承受超高压的前提下,可远程操作,迅速分离高压管道,使得作业船能够立即撤离,具有响应时间短、操作简易的特点,降低了平台作业风险。     

隧道高压压气作业实践指南(一)

<正>1概述1.1背景近年来,多座TBM隧道工程实施了带压(高压压缩空气)进舱作业,这是隧道界高压压气作业的一次重大进步,为此需要借鉴和利用潜水业的高压技术。1.2范围本指南适用于采用高压压气技术的隧道工程(包括竖井)。迄今为止,此类高压压气作业主要涉及TBM的保养与维修作业。不过,可以预见的是传统法施工的隧道工程也将不得不在高压压气下进行作     

岩溶地区钻孔灌注桩的施工方法和技术措施

本文通过对在岩溶地区钻孔灌注桩的施工方法与主要的技术措施介绍,系统说明了在岩溶发育地区进行钻孔灌注桩施工,是一项工作繁杂、工序严密、技术性强、工期较短、需连续三班作业的地下隐蔽工程。因此,为了提高和保证钻孔灌注桩的耐久使用性,应因地制宜,综合考虑地层性质、地下水、场地条件与环境、施工设备性能、起吊载荷大小等因素,精心组织好施工,制订切实可行的施工措施,以确保工程质量。     

阀门齿轮箱维护研究

阀门是管道系统中的重要组成部分,阀门的维护是生产运行中的主要工作之一。川气东送管线上兰州高压阀齿轮箱在投用时存在积液锈蚀现象,增加了维护保养难度和安全风险。文中从齿轮箱结构入手,通过分析典型兰高阀齿轮箱密封点,探讨齿轮箱积液的原因,运用接触式密封技术,在结构空间中选用合理的密封元件组合强化齿轮箱密封,彻底改变齿轮箱的密闭条件,实现水汽的隔离,保证齿轮箱的干燥运行条件。     

超音速分离在天然气脱水中的应用

根据低压和高压条件下的实验,研究了超音速分离技术在天然气脱水方面的应用。研究结果表明：超音速分离技术的脱水效果与压降条件有关,当压力超过7 MPa时,超音速脱水技术比透平膨胀机制冷脱水技术和J-T阀脱水技术更具优势。同时,对超音速分离脱水技术的应用前景进行了展望。     

油气长输管道管沟开挖技术

结合国内外长输管道施工实际 ,论述了管沟开挖遵循的原则、开挖技术要点、地下水位较高地段及山区地段开挖技术和开挖安全保证措施 ,提出了地形地势允许条件下 ,优先采用通过管沟开挖实现管道的弹性敷设和开挖方案的制定与开挖作业的风险评价相结合的观点     

高压水射流清洗作业中喷嘴的设计原理和选型依据

主要介绍了高压水射流清洗系统中喷嘴的设计原理和选型依据、实验结果,通过了解喷嘴的设计过程和影响喷嘴的性能因素,选择与清洗系统匹配的喷嘴,可以明显地提高清洗作业的效果,减少劳动损耗.     

高压水自动清洗作业井架(车)工艺装备研究与设计

介绍了一种以高压水射流技术为核心技术的自动清洗工艺装备，用于实现对油田作业井架（车）等大型设备进行自动化清洗。     

Survey of R&D in PRT systems

A survey of research and development in advanced transit has been made by Chalmers University of Technology in Gothenburg in cooperation with Trans21 in Boston. Summary findings are reported for fourteen academic research programs and ten development programs for PRT. An earlier version of this paper was presented at the International Conference of PRT and other Emerging Systems held in Minneapolis in 1996.     

Determinants of modal choice in freight transport

In the next few years, exciting developments in the field of freight transport are likely to occur. The Channel Tunnel will be perceived as giving railways much greater distance of operation, compared to the current train ferry to/from Great Britain. The further development of swap-body technology will allow easier modal transfer and the creation, in 1992, of a single market in Europe will transform the pattern of trade. All of these are likely to have significant impacts on modal choice, and hence modal split, in freight transport. Reappraisal by many firms of the modes of transport used is likely but will it result in a net transfer of freight from road to rail and, if so, to what extent? To answer such questions, an accurate and reliable method of predicting modal split is required. Research in the past has concentrated on the development of modal split models based on generalised costs. These fail to explain adequately the prevalence of road freight in the UK. From surveys of freight managers within industry, it is clear that models to date rely too heavily on the economic cost factor and too little on behavioural factors (Jeffs 1985). This paper derives from a recent study of freight transport modal choice from the standpoint of the transport decision-maker within the firm. It attempts to shed light on the actual parameters which should be incorporated into a modal split model. Many variables appear to exert an influence on modal choice decision-making process. However, it is possible to categorise them into six main groups, namely: customer-requirements; product-characteristics; company structure/organisation; government interventions; available transport facilities; and perceptions of the decision-maker him/herself. It is the interactions and inter-relationships between these which ultimately determine freight modal split. This study has shown that the relationship between the outcome of the transport decision process and the values of particular determinants of modal split is not straight-forward, due to the complexity and variety of interactions involved. Perhaps one of the main reasons for researchers' failure hitherto to develop a successful modal-split model has been the preoccupation with techniques that rely on the development of common metric (e.g. generalised cost), which has led to the exclusion of some important explanatory variables along quite different dimensions. Another important issue concerns the appropriate level of aggregation. In order not to reduce the explanatory power of the key variables, it is important to work at a disaggregate level, although this does make substantial demands on data. The use of factor analysis enables both the aggregation of information without loss of behavioural reality and the specification of variables in terms of a common metric. In conclusion, freight transport has usually been examined within too narrow a framework. It must be placed firmly within the context of the total industrial process. The demand for freight transport is directly influenced by the level, composition and geographical distribution of production and consumption activities. Freight flows are complex and so it is highly unlikely that a universal mode-choice model can ever be developed. Future research should, therefore, be directed towards developing partial models in response to specific needs of those involved in decision-taking in the freight sector.     

管道风险分析指数评分法中分值调整初探

管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一（各因素的分值范围都是0～100分）,为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。     

天然气站往复式压缩机活塞失效分析

针对天然气站往复式压缩机活塞的断裂事故,运用失效分析方法,开展了活塞断口扫描电镜分析、能谱和金相分析。根据断口形貌的电镜和金相观察结果,结合理论知识,分析确定了该活塞发生断裂事故的主要原因,即在特定工况下该活塞的材料缺陷是造成断裂的主要因素。     

中国城市道路规划方位性问题研究

文章结合中国的传统建筑文化理念和现代科学原理,从历史文化、能源节约、环境保护、房地产定价、交通安全等多方面分析研究了城市道路在规划和设计时所应遵从的定向规则。     

A century of evolution of the accessibility concept

The concept of accessibility has acquired numerous meanings along multiple dimensions during the century of its evolution. This essay argues for the salience of two dimensions: application-based and definition-based. In its application, accessibility has incorporated positive and normative dimensions which have varied in prominence over time. In its definition, accessibility has varied between a mode of evaluation incorporating measured mobility and proximity, on the one hand, and a predefined market basket of urbanist improvements to transportation and land use systems, on the other. Advocates of the accessibility shift should emphasize both the measured approach to accessibility and accessibility’s normative side.     

生命大过天

文章介绍了广西壮族自治区公路管理局开展专项行动,治理以桥梁为重点的交通基础设施安全隐患的情况,针对在役桥梁、在建桥梁和农村公路桥梁存在的安全隐患提出了相应的治理措施。     

Predicting queue variability to enable analysis of overload risk

ABSTRACT

Predicting the risk of traffic demands and delays exceeding critical limits at road junctions, airports, hospitals, etc., requires knowing how both mean and variance of queue size vary over time. Microscopic simulation can explore variability but is computationally demanding and gives only sample results. A computationally efficient approximation to the mean is used in many modelling tools, but only empirical extensions for variance in particular situations have been available. The paper derives theoretical formulae for time-dependent and equilibrium variance, believed to be novel and to apply generally to queues covered by the Pollaczek–Khinchin mean formula, and offering possible structural insights. These are applied in an extended approximation giving mutually consistent mean and variance estimates with improved accuracy. Tests on oversaturated peak demand cases are compared with Markov probabilistic simulation, demonstrating accuracy (R^2?>?0.99) for typical random, priority-like (M/M/1) and traffic-signal-like (M/D/1) queues. Implications for risk analysis, planning and policy are considered.     

Planning guidelines for metro–bus interchanges by means of a pedestrian microsimulation model

The big paradigm for cities nowadays is to study the movement of pedestrians at the interface between metro and bus systems – metro–bus interchanges. When these interchanges are not well designed, walking is inefficient and can be unsafe for pedestrians. This paper analyses, by means of a pedestrian microsimulation model, metro–bus interchange spaces in order to propose planning guidelines for the city of Santiago de Chile. Specific objectives are (1) to identify the variables that provide efficiency and safety in those spaces; (2) to simulate different scenarios using the pedestrian simulation model LEGION; (3) to propose planning and design guidelines for pedestrian spaces at metro–bus interchanges; and (4) to contrast the recommendations in the recently opened terminal station on Line 1 of Metro de Santiago: Los Dominicos Station.