各种热切割的原理与特征

今年是氧乙炔切割工艺面世100周年以及现代等离子切割工艺投入应用50周年。随着当代诸如电、光、电磁波等新型能源的应用,切割技术取得了长足的发展,尤其是最近超硬材料的切割、超精密切割等高端的切割技术在装备制造、交通运输等工业领域得到了广泛应用。本文着重介绍了气割、等离子切割、激光切割工艺的原理与特征。阐述了上述热切割技术的发展前景,对于各种热切割法的选择与保证加工质量提出了建议。     

西安地铁车站气体灭火系统研究

气体灭火系统是地铁建设中非常重要的一部分,负责保护地铁车站中重要的设备用房的安全。结合西安地铁工程实际情况,从安全、环保、投资控制及维护保养等方面对我国地铁工程设计中常用的七氟丙烷灭火系统、IG 541灭火系统,以及新型高压细水雾灭火系统进行综合分析对比,确定适合西安地铁车站的气体灭火系统为IG 541灭火系统,并给出了管网系统设计方案。     

无枕式整体道床长钢轨直铺法施工机具研究

无枕式整体道床施工机具的研究设计直接影响到施工效率及工程质量,结合马来西亚安邦轻轨延伸线工程特点,在长钢轨直铺法施工技术基础上进行配套施工机具的研究。主要是多功能轨道调整器及模板体系的研究,包括结构形式、施工方法、精度保证措施、小半径曲线施工实现方式等。采用MSC.Nastran软件对多功能轨道调整器进行强度及变形分析,并采取相应措施保证整体道床施工精度。     

天然气高瓦斯山岭隧道地质灾害的特点与预报

研究目的:开挖油气田区的高瓦斯隧道,有着极高的危害性。由于隧道底部围岩为油气层,成为隧道施工瓦斯的补给源。而且,不同于煤层瓦斯的是,油气田区瓦斯无处不在。只要有断层、节理带存在,通常会有瓦斯溢出。所以,在油气田区,必须密切关注节理、断层的位置。查明其位置、性质、产状、规模,判断其是否成为导气构造,以便及时采取措施,保证施工安全。研究结论:(1)对于油气田区隧道,只有在区域地质分析的基础上,充分认识瓦斯赋存的特点,才能认清瓦斯溢出(突出)的本质,掌握灾害发生的机理,从而制定出具有针对性的预报方案;(2)精确的地质分析可为TSP隧道物理探测奠定坚实的基础,有效地消除解译结果的多解性;(3)严格现场操作,规范探测与钻探施工是实现准确预报的必要条件;(4)地质与物探相结合、宏观与微观相佐证,步步为营,是成功探测的基础。     

电气化铁道对输（油）气管道的影响及防护措施

分析了电气化铁道对沿线输（油）气管道产生交流干扰的基本原理,提出了降低电磁干扰,维护输（油）气管道人身及设备安全的防护措施,具体阐述了牺牲阳极排流保护方式的原理及应用效果。     

Closed-loop Inventory Routing Problem for returnable transport items

Increasing concerns on supply chain sustainability have given birth to the concept of closed-loop supply chain. Closed-loop supply chains include the return processes besides forward flows to recover the value from the customers or end-users. Vendor Managed Inventory (VMI) systems ensure collaborative relationships between a vendor and a set of customers. In such systems, the vendor takes on the responsibility of product deliveries and inventory management at customers. Product deliveries also include reverse flows of returnable transport items. The execution of the VMI policy requires vendor to deal with a Closed-loop Inventory Routing Problem (CIRP) consisting of its own forward and backward routing decisions, and inventory decisions of customers. In CIRP literature, traditional assumptions of disregarding reverse logistic operations, knowing beforehand distribution costs between nodes and customers demand, and managing single product restrict the usage of the proposed models in current food logistics systems. From this point of view, the aim of this research is to enhance the traditional models for the CIRP to make them more useful for the decision makers in closed-loop supply chains. Therefore, we propose a probabilistic mixed-integer linear programming model for the CIRP that accounts for forward and reverse logistics operations, explicit fuel consumption, demand uncertainty and multiple products. A case study on the distribution operations of a soft drink company shows the applicability of the model to a real-life problem. The results suggest that the proposed model can achieve significant savings in total cost and thus offers better support to decision makers.     

Experimental analysis of exhaust gas after treatment system using water scrubbing in a single cylinder diesel engine for diesel and biofuel blends

A low-cost exhaust gas after treatment system called water-scrubbing is attempted in this paper. An emission treatment setup is fabricated, which is installed in the exhaust of the engine. This takes the exhaust gas and sprays water in the exhaust and passes it through the chamber containing silica gel. An attempt is made to investigate experimentally the performance and emission characteristics of a direct injection (DI) diesel engine, with and without water injection at the exhaust using diesel fuel (DF), diesel-Karanja oil blend (DKB) and diesel-Jatropha oil blend (DJB). The exhaust gas after treatment system helps to reduce NOx, CO and Particulate matter. The performance of the engine has also been monitored to determine whether the engine has any decrease in performance when the setup is used and it is found that there is no change in the engine performance.     

长输管道工程施工期环境监理研讨

长输管道工程对地质环境及景观生态环境的影响主要发生在施工期。为确保工程建设环境保护工作质量,有效控制施工过程对沿线生态环境影响,须引入环境监理监控。本文以国家“十一五”规划重点建设项目川气东送管道工程为例,进行了施工期环境监理模式、工作依据、内容和环境监理、监控成效探讨,为长输管道工程建设项目施工期环境监理工作的开展起到积极的推广和借鉴作用。     

伺服缸型电-气式主机遥控装置研究

伺服缸型电-气式主机遥控装置，其调速(调速器)控制部分运用微计算机“PID”编程控制技术，调速输出信号经“D／A”、“E／P”转换为标准气压信号，由调速器执行器即伺服气缸比例输出，对主柴油机进行转速、负荷控制。在我国以“V390”系列主柴油机为主动力装置的高速船舶数船队中，船舶主机遥控毫无例外地都应用了伺服缸型电-气式主机遥控装置。     

135系列柴油机缸套穴蚀成因分析

文章在分析135系列柴油机缸套穴蚀原因的基础上,给出了消除穴蚀的方案.