LNG汽化站的工艺设计

论述了液化天然气汽化站的工艺流程,主要针对LNG汽化站主要设备的工艺设计问题进行探讨,并介绍了LNG汽化站的安全设计.     

红外辐射加热在深水保温管节点补口中的应用

在深水GSPU湿式保温管道节点补口施工中,主体保温层预热效果对节点浇注材料(CPU)和GSPU之间的界面粘接强度起到关键性的作用。文中将先进的红外辐射加热技术引入到节点施工中,大量实验证明红外辐射加热的效果良好,能耗低、效率高,工艺简单可靠。同时,利用开发的节点红外辐射加热装置开展了GSPU湿式保温管模拟工艺试验,结果证明该套工艺和设备可满足节点施工的工艺技术要求。     

一种用于蒙乃尔400材料制造的U形管束工艺方案

蒙乃尔400材料是一种价格昂贵的镍基耐腐蚀材料,属于贵重的容器用材,因此有必要研究出一套经济可行的工艺方案。文中以1台用于烷基化装置的该材质U形管束为例,针对制造所涉及主要难点问题,详细论述了制造该设备主要工艺方案,如焊工考试和焊接工艺评定、材料复验、弯管、机械加工、表面处理等需要特别注意的细节问题;重点给出了热处理、组装、焊接及压力试验等难点问题的具体解决措施。按以上的工艺方案,制造出了符合用户质量要求的产品。     

LNG项目柔性材料管道保冷施工

随着液化天然气（LNG）项目的不断发展,新型的管道保冷材料被广泛应用。文中结合某LNG项目管道柔性保冷材料的实际施工情况,对柔性保冷材料的施工工艺从环境要求、保冷结构、施工顺序等几个方面进行研究,总结出了最适合的保冷施工工艺,为其他LNG项目管道保冷材料的选型提供参考,为管道保冷施工提供参考。     

相变加热炉在稠油管道上的应用

目前稠油采用加热输送的方式,通过对多种加热炉的比选,相变加热炉具有安全、环保、节能、高效等优点,可做为稠油输送的加热设施,并对其应用实例进行了分析.实际应用表明,该设备具有很好的经济效益.该产品在油气集榆、处理等需要加热领域具有良好的应用前景.     

液化天然气(LNG)接收站运营输量控制研究

文中以某一运行的LNG接收站为研究对象,在分析现有再冷凝工艺对相对最小外输量控制的基础上,对影响外输量的主要操作参数进行详细分析,然后提出具体改进方案,应用于实际操作过程,证明了此方案能够有效地降低相对最小外输量,满足接收站在特殊工况下对外输量的要求,具有较好的可行性和可操作性.     

沥青拌和设备输送管道预热技术改良方案研究

随着公路建设大发展,公路养护工程小修保养及公路应急抢修工程项目不断增加,这类工程具有规模小、频率高、时间紧、不连续等特点,对沥青生产设备的响应能力、设备效率等方面提出了挑战.针对此问题,文章提出了利用16.9m的泵送管道将小罐加热的沥青输送到拌和楼的技改方案,使沥青输送管道的预热时间仅为原系统用时的1/5,沥青加热用煤仅为原来的1/20,有效缩短了沥青生产时间,减少了加热能耗.     

浅析高桩码头装卸工艺基础结构安全评估方法

文章依托于某高桩码头装卸工艺升级改造工程,基于通用结构安全评估方法,结合高桩码头结构、装卸工艺和计算等特点,提出一套实用、简明的高桩码头装卸工艺基础结构安全评估方法。依托工程评估实例表明,已建卸船机基础结构初始评估等级D级,当将卸船机基础位置平移至邻近横梁后,结构评估等级可达到A级,建议卸船机采用此方案进行整改;未建卸船机建设位置选择于立柱正中,结构评估等级可达到A级,推荐卸船机采用此方案进行建设。研究成果可为依托工程提供依据及为类似工程提供参考。     

海底隧道全强风化花岗岩地层注浆技术研究

厦门翔安海底隧道施工中面临着穿越浅滩全风化岩层、沙砾层透水胶结带和海底全强风化深槽等3大控制性工程难点,为此由建设、设计、研究、施工等各方立项进行了前期可行性研究.文章对注浆工艺、注浆材料、注浆参数等进行了专题研究.并结合服务隧道工程的注浆试验实施,提出了在全强风化花岗岩地层中注浆加固的可行性及其相应的注浆方案、工艺、参数和设备的确定.     

LNG低温管托的结构特点及材料选用

LNG(液化天然气)在输送过程中,冷量泄漏易汽化产生BOG气体,会严重影响接收站的经济收益。在设计过程中,考虑低温管托需承重,其选用的保冷材料与管道本体不同,选择合适的结构和材料,可以最大限度地减少冷量泄漏。文中介绍一种低温管托的设计要求、结构特点和材料选用,该管托在实际应用过程中表现出良好的保冷性能且施工方便,值得推广应用。     

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.     

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。     

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.     

Real-world gaseous and particle emissions of a Bi-fuel gasoline/CNG Euro 6 passenger car

The objective of the present study is the assessment of the environmental impact of a bivalent (bi-fuel) vehicle, running either on gasoline or compressed natural gas (CNG). To that aim, a Euro 6 passenger car was tested under various real-world driving conditions. In order to cover the full range of conventional powertrains currently in the market, the tests were also repeated on a Euro 6 diesel passenger car. Both cars were driven in two routes, the first complying with the regulation limits and the second going beyond them. Carbon monoxide (CO), nitrogen oxides (NO_x) and particle number (PN) emissions were recorded using a Portable Emissions Measurement System (PEMS). Apart from the aggregated emission levels, in g/km, the exact emission location along the route was also assessed. Natural gas proved beneficial for CO and PN emissions, the level of which always remained below the respective legislation limits. On the other hand, under the dynamic driving conditions with gasoline, the relevant limits were exceeded. Cold start, occurring at the beginning of the urban part, and motorway driving were identified as major contributors to total emissions, especially in gasoline mode. However, the application of natural gas was associated with a penalty in NO_x emissions, which were significantly increased as compared to gasoline. Local peaks within the urban part were identified in CNG mode. In any case, the diesel vehicle was by far the highest NO_x emitter.     

Seaport performance analysis using robust non-parametric efficiency estimators

Abstract

Seaport services have been developing year on year, playing an increasingly important role in the economy and the transportation markets of each country. This increases interest in measuring their performance. This paper evaluates the performance of a set of European seaports by means of robust non-parametric approaches. Using order-m and bootstrap procedures, the major problems of traditional data envelopment analysis and free disposal hull methods – concerning noise, presence of outliers and the ‘curse of dimensionality’ – are overcome. With this study considerable levels of inefficiency were found in the European seaports sector.     

Bicycle parking: a systematic review of scientific literature on parking behaviour,parking preferences,and their influence on cycling and travel behaviour

ABSTRACT

Cycling is experiencing a revival in many cities. Research has focused on the determinants of cycling – in particular the role of the built environment and road infrastructure. Bicycle parking has received little attention – even though bicycles are parked most of the time. This article reviews the scientific literature on bicycle parking and identifies existing gaps in research and knowledge. The review analyses 94 peer-reviewed papers identified through a search in Scopus and Web of Science, in December 2017. The annual number of papers increased 15-fold between 1995 and 2017. Overall, the level of evidence on the importance of bicycle parking is limited. The majority of studies are based on cross-sectional data with the presence of parking as a binary independent variable. Most studies focus on bicycle parking at public transport stops and at work places. Few studies report on bicycle parking throughout cities, and hardly any on parking at residential locations. Bicycle parking supply and quality appears to be a determinant of cycling for current and potential cyclists. Our findings can serve as input for an evidence-based debate on the role of bicycle parking. For practitioners, our research supports investment in bicycle parking, but acknowledges that a proper evaluation of such initiatives needs to be conducted to increase the level of evidence.     

Multilevel analysis of daily time use and time allocation to activity types accounting for complex covariance structures using correlated random effects

In this paper multilevel analysis is used to study individual choices of time allocation to maintenance, subsistence, leisure, and travel time exploiting the nested data hierarchy of households, persons, and occasions of measurement. The multilevel models in this paper examine the joint and multivariate correlation structure of four dependent variables in a cross-sectional and longitudinal way. In this way, observed and unobserved heterogeneity are estimated using random effects at the household, person, and temporal levels. In addition, random coefficients associated with explanatory variables are also estimated and correlated with these random effects. Using the wide spectrum of options offered by multilevel models to account for individual and group heterogeneity, complex interdependencies among individuals within their households, within themselves over time, and within themselves but across different indicators of behavior, are analyzed. Findings in this analysis include large variance contribution by each level considered, clear evidence of non-linear dynamic behavior in time-allocation, different trajectories of change in time allocation for each of the four dependent variables used, and lack of symmetry in change over time characterized by different trajectories in the longitudinal evolution of each dependent variable. In addition, the multivariate correlation structure among the four dependent variables is different at each of the three levels of analysis.     

从"神经末梢"到"国际枢纽"——十六大以来广西交通发展综述

文章总结了党的十六大以来广西交通发展取得的成绩,指出广西交通正在从"神经末梢"发展为"国际枢纽",为广西经济社会发展提供了重要支撑。     

Increasing urban tram system efficiency,with battery storage and electric vehicle charging

This paper examines the possible placement of Energy Storage Systems (ESS) on an urban tram system for the purpose of exploring potential increases in operating efficiency through the examination of different locations for battery energy storage. Further, the paper suggests the utilisation of Electric Vehicle (EV) batteries at existing Park and Ride (P&R) sites as a means of achieving additional energy storage at these locations. The study achieves this through MATLAB modelling utilising captured GPS data and publically available information. This study examines the scenario of uni-directional substations with no interconnection between the overhead catenary for both directions of travel, and discusses the trade-offs between ESS size and required current limits.The results show the savings in both energy and basic CO₂ emissions alongside the discussion of Return on Investment (RoI) that can be achieved through the potential installation of ESS at identified ideal locations along the tram network. Moreover, this may be extended to the use of EVs as stationary ESS sited at the existing P&R facilities. Further, the model may also be used to inform future infrastructure upgrades and potential improvements to air quality within urban environments.