陶瓷内衬复合钢管的研制及在矿山的应用

利用ＳＨＳ铝热－离心铸造技术制备的陶瓷内衬得合钢管具有优异的耐磨损性能，可广泛地应用于矿山、电力、才等工业部门，本文讨论和分析了制备陶瓷内衬复合钢管的基本原理，结构、性能及其在矿山等工业部门的应用前景。     

Programmatic Cost Risk Analysis for Highway Megaprojects

Highway megaprojects (construction projects over $100 million) are fraught with uncertainty. These projects have historically experienced increases in project costs from the time that a project is first proposed or programmed until the time that they are completed. Persistent cost underestimation reflects poorly on the industry in general but more specifically on engineers. Traditional methods take a deterministic, conservative approach to project cost estimating and then add a contingency factor that varies depending on the stage of project definition, experience, and other factors. This approach falls short, and no industry standard stochastic estimating practice is currently available. This paper presents a methodology developed by the Washington State Department of Transportation (WSDOT) for its Cost Estimating Validation Process. Nine case studies, with a mean cumulative value of over $22 billion, are presented and analyzed. Programmatic risks are summarized as economic, environmental, third party, right-of-way, program management, geotechnical, design process, construction, and other minor risks. WSDOT is successfully using the range cost output from this procedure to convey project costs to management and the public.     

孟加拉国凝析油处理厂总图设计分析

通过对孟加拉国凝析油处理厂项目在总图运输设计当中的特点,分析了场地的布局设计、平面竖向分析,叙述了主要工程做法,当地气候对设计产生影响,今后如何提高对外项目设计水平。     

弯头直角管道顺序输送混油特性的数值模拟

通过多相流模型对成品油管道进行数值模拟,以汽油和柴油作为顺序输送对象,分别就直角弯管向上、直角弯管向下两种工况时研究输送顺序、重力、管径、粘滞力对混油的影响,研究结果表面:当直角弯管向上时前行柴油的混油量小于前行汽油的混油量,当油品运行到竖直管道时,前行柴油比前行汽油油品运行的缓慢,前行柴油混油的倾斜角度大于前行汽油混油的倾斜角度;当直角弯管向下时前行汽油的混油量小于前行柴油的混油量,前行汽油混油的倾斜角度大于前行柴油混油的倾斜角度。通过对比可以看出:直角弯管向上前行柴油时混油运行的最为缓慢。无论是前行汽油还是前行柴油管径越大混油量越小,当管径相等时前行柴油比前行汽油的混油长。该数值模拟与管道实际结果相一致。     

液化天然气储罐翻滚事故分析

随着世界能源紧缺现状的出现,天然气工业在我国的不断发展,液化天然气成为了一种成效卓著的储运方式,那么,随乊而来的便是液化天然气的安全问题,分层、翻滚是液化天然气在储存过程中有可能出现的一种极其危险的事故现象。通过FLUENT模拟软件对LNG储罐中不同物性参数的液化天然气在罐体漏热情况下进行数值模拟,在此乊前通过计算对大型LNG储罐漏热进行求解,将计算得到的热流密度近似取成10W/m2,以此作为模拟时边界条件的罐壁、罐底漏热量,模拟得出翻滚发生的开始和结束时间,最后通过翻滚发生持续时间计算仅翻滚时所造成的LNG损失,约334 t,翻滚发生前,储罐内的气相空间压力梯度约为32 kPa/h,仅约20 min便会使储罐内正常操作压力超出安全阀设定压力。由此可见,液化天然气翻滚事故的发生不仅会造成液化天然气本身的一大浪费,同时也会对人身及财产安全构成巨大威胁,因此,深入研究LNG翻滚对社会发展具有深远意义。     

有限数据支持下的城市土地开发强度确定方法——以武汉市东西湖区107国道实施性规划为例

当前巨大的人口和空间需求推高了我国城市的土地开发强度,在多数地区缺乏交通模型和交通量数据支持的情况下,土地开发强度通常依托规划师的经验来确定,这有可能带来后续的城市出行结构恶化和交通拥堵等一系列矛盾。在宏观的交通发展战略指导下,从中观、微观层面研究与城市局部交通系统容量等多要素相适应的土地开发强度是解决此矛盾的重要途径。研究以武汉市东西湖区107国道为例,从与土地开发强度相关的上位规划的控制要求、公交导向发展和拆建比等要素出发,初步确定了开发区域内土地的强度指标。同时,构建起局部交通模型对开发区域的强度指标进行校核,以达到协调城市局部用地开发与交通设施一体化发展的需求。     

产业、空间与交通一体化的临空经济区发展规划技术体系

随着经济全球化的发展,临空经济区开始成为世界经济发展的重要组成部分。临空经济区的形成是航空经济在产业、空间、交通三要素协同演化下的结果,同时也是政府出于刺激经济发展目的下主动规划的产物。因此,从产业、空间、交通三要素协同的角度对临空经济区进行规划是新型城镇化背景下激发其作为城市经济增长极的重要途径。研究从分析产业、空间、交通三要素的基本关系入手,提出了基于三要素协同发展的临空经济区发展规划技术体系,并分别对产业、空间、交通体系中的核心技术方法进行了探讨。     

Behaviors and housing inertia are key factors in determining the consequences of a shock in transportation costs

This paper investigates the consequences of a sudden increase in transportation costs when household behaviors and building inertia are accounted for. A theoretical framework is proposed, capturing the interactions between behaviors, transportation costs and urban structure. Numerical simulations show that changes in households and landowners’ choices reduce significantly the long-term adverse effects of a shock in transportation costs. Indeed, the shock translates, over the long run, into a more concentrated housing that limits households utility losses and maintains landowners’ income. But, because of building inertia, the shock leads first to a long transition, during which the adjustment is constrained by a suboptimal housing-supply structure. Then, households support larger losses than in the final stage, though lower than with no behavior adjustment, and landowners experience a large decrease in their aggregate income and an important redistribution of wealth. Thus, behaviors and building inertia are key factors in determining the vulnerability to transportation price variability and to the introduction of climate policies. Our policy conclusions are that: (i) if a long-term increase in transportation costs is unavoidable because of climate change or resource scarcity, a smooth change prevents to some extent the negative transition effects and (ii) fast-growing cities of the developing world can reduce their future vulnerability to shocks in transportation costs through the implementation of policies that limit urban sprawl.     

中国炼焦煤供需现状及其发展趋势

近年来,国际炼焦煤市场供需两旺,价格飙升。作为世界最大的炼焦煤生产国和消费国,中国的炼焦煤及其焦炭产品市场更是一片火热。如何看待目前和未来一个时期中国炼焦煤市场的供需关系?影响这一关系的主要因素有哪些?探讨这些问题无论对于国家宏观调控还是企业微观运行决策都有十分重要的现实意义。认为,从2001年到2010年,中国的炼焦煤供需呈较快的增长态势且增速前高后低,保持供需基本平衡、局部供应偏紧,价格高位的发展态势。其主要影响因素是国内大中型煤矿的生产能力增速和非法煤矿产量的减速以及钢铁工业的发展速度等。