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Transportation - Previous studies have indicated that positive (or negative) experiences of activity episodes are likely to correlate with positive (or negative) evaluations of a persons’... 相似文献
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现浇立交桥的跨线施工中,使用少支点支架进行施工,不仅满足了下跨线的安全运营问题,而且操作简单、快捷,施工质量也可以得到了保证。该文结合苏州工业园区北环路东延工程整体现浇跨越苏嘉杭高速施工过程,介绍了少支点支架在跨线桥整体现浇施工中的关键技术,可供桥梁施工人员参考。 相似文献
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焊接残余应力及其控制技术是重大工程结构物(例如反应堆、潜艇等)建造中关注的核心问题之一。爆炸法消除残余应力是近年来发展起来的高效、低成本的1种新技术,但对其机理的研究仍然相当缺乏。本文利用非线性有限元软件ABAQUS对爆炸消除焊接残余应力技术进行了数值模拟,同时考察了焊缝中夹杂的裂纹缺陷对爆炸载荷的响应。研究对象为70 mm厚的超厚钢板对接焊缝,焊接坡口为X型。本文主要完成了以下2项研究工作。1)将盲孔法测得的焊接残余应力分布预置到模型中,计算了爆炸载荷作用下不同布药方式时焊接残余应力的再分布,并将其与对应的实测结果进行比较。研究结果表明,金属材料的塑性流动是爆炸消除焊接残余应力的根本因素。2)在模型的焊缝区引入面状裂纹来表征焊缝中的凝固裂纹,利用ABAQUS用户自定义子程序开发的基于虚拟裂纹闭合法的三维断裂单元,计算能量释放率对爆炸载荷的响应。研究结果表明,爆炸载荷并不一定会导致裂纹的扩展。因此,本文的研究方法和结果对于爆炸消除焊接残余应力在工程应用领域具有指导意义。 相似文献
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The project appraisal method in the Netherlands distinguishes direct effects, indirect distribution effects and indirect generative effects. Transport models are generally available for calculating the benefits of transport projects to travellers as part of the direct effects. The TIGRIS XL model, a Land-Use and Transport Interaction model, adds indirect distribution effects for the housing and labour market, by modelling changes in the spatial distribution of jobs and residents. This paper describes the current TIGRIS XL model and how it can be applied in the evaluation of transport projects. It refers to work done with the TIGRIS XL model to improve the calculation of the direct benefits by applying the so-called ‘logsum’ method. Finally it discusses ideas on how to extend the TIGRIS XL model to address indirect generative effects as well.The current TIGRIS XL model, its integration with the National Model System (the standard tool for the Dutch government to analyse the effects on passenger transport) and basic design principles are the starting point of such an exploration. These design principles include:
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- an emphasis on detail, both spatial as well as in socio-economic segments, to account for differences in the availability of choice alternatives and in choice behaviour, and to provide impacts by region and socio-economic group;
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- the requirement that the relationships used rest on an empirical foundation.
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A practical assessment of stated preferences methods 总被引:1,自引:0,他引:1
Stated preferences data in the form of rankings, ratings and choices were collected in Santiago and discrete choice models estimated with them. The models were compared in terms of accuracy v/s the cost of obtaining the information and models. All methods produced reasonable but different models and fairly close subjective values of time. In terms of production costs the ranking method was a clear looser although the experimental design was slightly biased against it. Finally, the use of computerised interviews is highly recommended particularly for dealing with low income people. 相似文献
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本文介绍了福州魁歧排涝站施工中地下水情况.介绍了采用单管旋喷防渗墙、钢板桩加高喷法封底、井点降水法、集水井、台阶式开挖支护压底等方法来解决施工排水问题,并对他们的效益作出分析总结。 相似文献
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As integrated supply-chain management (SCM) is now at the epicentre of business transformation, firms are breaking down boundaries between internal functions, as well as between the enterprise itself and key partners in the value chain (e.g. customers, distributors, suppliers and carriers). One of the main goals of such new management approach is to get everyone in the supply chain into a common platform of logistics transactions and information systems.
Against such background, the aim of this work is to analyse how and if port operators can face the challenge of higher integration, on the assumption that the higher the integration between the actors the higher the competitiveness of the whole supply chain.
Accordingly, we adopted an SCM approach in the analysis of the port of Le Havre in Renault's supply chain. More specifically, we referred to the Lambert tri-dimensional model based on supply chain's structure (actors), key business processes and links between actors. The field work—which mainly consisted of semi-structured interviews to Renault, logistics and port operators, and, finally, to the Le Havre Port Authority—was crucial to gather the needed information. 相似文献
Against such background, the aim of this work is to analyse how and if port operators can face the challenge of higher integration, on the assumption that the higher the integration between the actors the higher the competitiveness of the whole supply chain.
Accordingly, we adopted an SCM approach in the analysis of the port of Le Havre in Renault's supply chain. More specifically, we referred to the Lambert tri-dimensional model based on supply chain's structure (actors), key business processes and links between actors. The field work—which mainly consisted of semi-structured interviews to Renault, logistics and port operators, and, finally, to the Le Havre Port Authority—was crucial to gather the needed information. 相似文献
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