三峡升船机塔柱横梁混凝土施工技术

三峡升船机船厢室段塔柱承重结构的横梁混凝土浇筑施工难度大、复杂性高、无成熟技术可供参考。本文结合三峡升船机塔柱横梁混凝土浇筑的结构特点以及施工特性,总结了三峡升船机续建工程顶部横梁混凝土的施工技术,即采用分层、分块浇筑的办法,通过科学计算后进行合理的施工机械布置和浇筑施工管理,以保证塔柱横梁混凝土的施工质量。通过对贝雷架支撑系统的监测结果分析可知,贝雷架支撑系统的应力变形、挠度变形以及排架变形均满足施工承载要求,筒体位移亦满足技术要求,贝雷架支撑系统稳定、安全。三峡升船机塔柱横梁混凝土施工实践证明了本技术方案的有效性与可靠性,亦可为类似工程的施工组织设计与现场实施工作提供一定的参考。     

三峡升船机液压自升式模板施工技术

三峡升船机塔柱混凝土施工工期紧,精度要求高,为保证施工进度和质量,采用了液压自升式模板。本文重点介绍了三峡升船机塔柱混凝土液压自升式模板施工技术、自升式模板改进措施以及为满足自升式模板上升而在塔柱板梁、牛腿处进行的结构处理措施。实践证明,液压自升式模板施工技术的应用与改进满足了三峡升船机塔柱筒体混凝土的设计要求,有效地提高施工效率、节约了成本,保证了工程质量并提高施工的安全性,可为其他水电工程施工提供借鉴。     

三峡升船机塔柱混凝土温控防裂技术

三峡升船机塔柱结构复杂,属于高层薄壁结构,混凝土温度受环境温度影响较大,其混凝土温控难度极大。在施工实践中,通过优化混凝土配合比、合理布置混凝土冷却系统、科学调控冷却水温度与通水时间,科学调整外部环境温度、同时引进混凝土养护新材料、新工艺,并且加强对温控的施工管理等措施,保证了塔柱混凝土的施工质量,证明了温控方案的科学合理性。三峡升船机塔柱混凝土温控防裂技术对研究国内外升船机工程温控措施技术水平,提高水电工程混凝土施工质量,节省工程造价等具有重要的参考价值。     

三峡特大型垂直升船机机电埋件及设备高精度安装技术研究与应用

三峡垂直升船机是三峡水利枢纽建筑的一部分,是为通航客船提供快速过坝的通道。本文针对国内外尚无先例的三峡垂直升船机设备安装高、精、尖施工技术难题,开展了大体积混凝土、高精度测量控制技术及大型金属结构设备埋件高精度安装等一系列关键施工技术研究,解决并实现了特大型垂直升船机施工安装技术的重大突破。本文总结了该技术的研究应用和工程实践经验,可为类似工程提供借鉴。     

三峡升船机塔柱施工技术

本文介绍了塔柱结构的整体施工程序,并详细分析了土建结构精度控制、金属结构及其埋件精度控制、混凝土温控防裂和安全控制等几个方面的施工重点与难点问题。同时,就塔柱结构在施工过程中采用的施工测量控制技术、薄壁混凝土温控防裂施工技术、高精混凝土连续快速施工技术、金属结构埋件施工技术、高空大跨度横梁结构施工技术等进行了系统的总结。上述施工技术的应用,不仅满足了塔柱高精度的施工要求,保证了塔柱施工的顺利进行,同时也为类似的高精混凝土的施工打下了坚实的基础。     

三峡升船机船厢室施工程序研究

针对三峡升船机船厢室平衡重和船厢荷载的施加顺序对塔柱埋件结构部位变形的影响,对船厢室的施工顺序和设备安装顺序方案进行了研究,解决了船厢和平衡重荷载的施加顺序对螺母柱、齿条和纵向导向变位影响的施工技术难题。根据对塔柱结构进行的仿真计算结果,分析了船厢与平衡重荷载施加顺序分别对螺母柱、齿条、纵向导向部位横河向、顺河向和竖向变形的影响,通过对施工程序优化提出了合理的升船机船厢室的施工程序以及施工总进度计划安排。该施工程序能够使螺母柱、齿条、纵向导向、船厢结构与塔柱在各工况下的位移满足安全要求,并且基于该施工程序的施工进度满足升船机试运行要求。工程实践证明了本文所建立的三峡升船机船厢室施工程序的合理性与科学性,确保了三峡升船机船厢室的顺利施工,保障了升船机的安全运行,可为类似升船机船厢室的施工提供参考。     

三峡升船机高精度金属结构埋件安装技术

针对三峡升船机工程金属结构一期及二期埋件的布置特点,并结合现场施工环境,对高精度安装作业进行了详细分析,提出了适宜三峡工程金属结构埋件安装的多种施工方案,并在三峡工程中得到广泛成功应用,解决了施工中埋件变形控制、快速高精度调整定位和高精度测量保障等技术难题,为同类工程的施工提供了借鉴。     

三峡升船机贝雷架安装与拆除技术

三峡升船机塔柱横梁贝雷架支撑体系的安装与拆除属于高空立体交叉作业,而且施工场地狭窄、施工强度大,贝雷架的安装与拆除所受到的施工干扰大,是三峡升船机塔柱施工中的难题之一。本文通过对贝雷架施工作业环境的系统分析,根据不同部位的特点与要求,制定了有针对性的包括施工设备布置、吊装单元划分、吊点设置、各部位拆除方案在内的塔柱横梁贝雷架安装及拆除施工技术体系。该技术体系在三峡升船机贝雷架安装及拆除工程中得到顺利实施,塔柱横梁贝雷架支撑系统的施工进度、施工成本及施工安全均实现了良好的效果,表明该技术方案合理可靠。本文中贝雷架的安装与拆除施工技术体系可为类似条件下的贝雷架安装和拆除施工提供参考借鉴。     

三峡升船机塔柱高空作业升降平台研究与应用

在三峡升船机续建工程中,因总体施工程序的调整,形成了塔柱筒体与齿条、螺母柱、平衡重、纵导向导轨等部位多重立体交叉施工作业的情况。在常规排架方案不能满足施工需要的情况下,研究并实施了可满足不同部位、不同工序、可迅速垂直转换施工部位的高空综合作业升降平台。该平台包括卷扬提升升降平台、齿轮齿条升降平台、吊挂升降平台等几种类型,可满足升船机金属结构埋件安装、二期混凝土施工、机电设备安装、二期混凝土浇筑、pagel灌浆等施工作业的需要,大大缓解了机电工程、金属结构工程施工工期紧张的情况。本项技术经过适配性设计后,可推广应用于水工建筑各种类型垂直导向快速施工的高空作业中。     

水工高精混凝土施工技术创新与实践

本文以三峡工程升船机中的高精混凝土施工为背景,阐述了水工高精混凝土的涵义、施工技术要点以及施工实践。详细介绍了三峡升船机高精混凝土施工的主要精度控制标准、高精度测量技术、高精混凝土施工技术和混凝土形体检测结果。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.