石油公司紧盯哪些“缺陷”

石油公司检查官依据最新版本VIQ要求对船舶进行检查,发现不完善的地方要记录在SIRE(Ship inspection report)报告中,称之为观察项(Observation),早期则是以"缺陷" (Deficiency)来表示.为避免争议,现统一用"观察项"代替"缺陷",其意为"检查官发现的问题,它可能是缺陷,也可能是依据专业知识判断该现象有欠缺,或者不完美".比如,一张使用陈旧的海图字迹不清晰,如果更换不及时,检查官就会把它当作一个观察项.那么,海图陈旧到怎样的程度才需要更换?这就没有标准答案,但检查官认为观察到这一欠缺,就要在报告里记录下来.     

浅谈路面工程的基层连铺施工方法

结合沂邳线苍山段路面翻修工程,对路面基层上下两层连铺的施工工艺、重点难点进行了探讨,给出了控制施工质量的方法,分析了这种施工方法的社会经济效益.     

Computational fluid dynamics-based multiobjective optimization of a surface combatant using a global optimization method

The main objective of this article is to describe the development of two advanced multiobjective optimization methods based on derivative-free techniques and complex computational fluid dynamics (CFD) analysis. Alternatives for the geometry and mesh manipulation techniques are also described. Emphasis is on advanced strategies for the use of computer resource-intensive CFD solvers in the optimization process: indeed, two up-to-date free surface-fitting Reynolds-averaged Navier-Stokes equation solvers are used as analysis tools for the evaluation of the objective function and functional constraints. The two optimization methods are realized and demonstrated on a real design problem: the optimization of the entire hull form of a surface combatant, the David Taylor Model Basin—Model 5415. Realistic functional and geometrical constraints for preventing unfeasible results and to get a final meaningful design are enforced and discussed. Finally, a recently proposed verification and validation methodology is applied to assess uncertainties and errors in simulation-based optimization, based on the differences between the numerically predicted improvement of the objective function and the actual improvement measured in a dedicated experimental campaign. The optimized model demonstrates improved characteristics beyond the numerical and experimental uncertainty, confirming the validity of the simulation-based design frameworks.     

港口物流发展模式探讨

从全球港口发展的阶段来看,发达同家自进入后工业化时期,现代港口已步入第三代港口发展期.最为显著的特征表现为:工业向柔性和个性化方向发展,虚拟企业开始出现,港口成为全球牛产、销售等整个供应链中重要的节点,加之高新技术在港口领域得到伞面应用,港口功能进一步完善,成为全球资源配置的重要枢纽.港口作为国际物流活动主要的载体,在国际贸易与国际经济合作中愈来愈发挥着重要作用.本文就世界几大先进港口的发展模式进行分析,研究其各白发展优势,总结规律,可为其他港口物流的发展提供借鉴.     

激光切割在机车钢结构件制造中的应用

文章初步探讨激光切割在机车钢结构件制造中的应用,并根据实践对影响碳钢板材切割质量的因素进行分析,给出了一套控制加工质量的工艺参数。     

A suggestion of gap flow control devices for the suppression of rudder cavitation

This paper presents the numerical analysis of rudder cavitation in propeller slipstream and the development of a new rudder system aimed for lift augmentation and cavitation suppression. The new rudder system is equipped with cam devices which effectively close the gap between the horn/pintle and movable wing parts. A computational fluid dynamics code that solves the Reynolds-averaged Navier–Stokes equations is used to analyze the flow field of various rudder systems in propeller slipstream. The body force momentum source terms that mimic flow field behind a rotating propeller are added in the momentum equations to represent the influence of the propeller and its slipstream. For detailed explication of the new rudder system’s lift augmentation and cavitation suppression mechanism, three-dimensional flow analysis is carried out. Simulations clearly display the mechanism of the lift augmentation and cavitation suppression. The computational results suggest that the Reynolds-averaged Navier–Stokes-based computational fluid dynamics reproduces the flow field around a rudder in propeller slipstream and that the present concept for a cavitation suppressing rudder system is highly feasible and warrant further study for inclusion of the interaction with hull and mechanical design for manufacturing and operations.     

Modeling nonlinear roll damping with a self-consistent,strongly nonlinear ship motion model

Appropriate modeling of roll damping is one of the key issues in accurately predicting ship roll motion. The difficulties in modeling roll damping arise from the nonlinear nature of the phenomena. In this study, we report a new effort in modeling the bilge keel roll damping effect based on the blocking mechanisms of an object in the potential flow. This effect can be implemented as a component of appropriate ship motion models. We used our digital, self-consistent, ship experimental laboratory (DiSSEL) ship motion model to test its effectiveness in predicting ship roll motion. Our numerical experiment demonstrated clearly that the implementation of this roll damping component improves significantly the accuracy of numerical model results (the results were compared with ship experiment data from the Naval Surface Warfare Center, Carderock Division, Maneuvering and Seakeeping Facility).     

Evaluation of consequence assessment methods for pool fires on water involving large spills from liquefied natural gas carriers

This article concerns thermal radiation hazards associated with unconfined liquefied natural gas (LNG) spills on water. Consequence assessment methods were compared to clarify their model characteristics in large-scale LNG spills from an LNG carrier (LNGC). The consequences of LNG release, pool spread, and pool fire hazards were estimated using the following practical methods: the Federal Energy Regulatory Commission’s (FERC) method, the Sandia National Laboratories’ method, and the Fay method. The sensitivity of consequence analysis results to the breach size of a tank was examined under the assumption that LNG is released from a common type LNGC of 125000 m³ cargo capacity. Consequently, it was found that the FERC method is useful from the practical viewpoint of being applicable to any breach size. Finally, thermal radiation hazards from pool fires involving spills from one of the latest and largest LNGCs (250 000 m³ cargo capacity), which are currently considered for construction, were investigated using the recommended FERC method, and the results are discussed in comparison with those for common type LNGCs. As a result, it was found that the maximum thermal hazard distance is longer by only about 24% compared with the common type LNGC, whereas the spill volume is twice as much.     

长沙一高层建筑风化砾岩地基承载力试验研究

以长沙市一高层建筑为工程背景,通过岩石饱和抗压试验和岩基载荷试验的对比研究,发现由载荷试验得到的岩石地基承载力特征值比由单轴抗压试验得到的要大;岩基载荷试验能更客观地反映岩石地基的承载力;岩石地基在栽荷作用下的变形表现出非线性弹塑性特征,用二次曲线拟合荷载一沉降曲线效果良好;给出了岩基承载力特征值建议取值,为人工挖孔灌注桩的设计施工提供了依据.