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The Effect of Bridging Liquid Surface Tension and Specific Surface Area on Streng.h Factor of Coal Agglomerates

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Journal of mechanics eng.neering and Automation 2012年第2期2卷 91-95页

作者： Kingsley Okechukwu Ikebudu Emmanuel Chuka Chinwuko Emmanuel Okechukwu Chukwumuanya dept. of mechanical eng.neering Faculty of Eng. ＆ EVM Anambra State University Uli Campus Anambra State 431124 Nigeria Department of Industrial/Production eng.neering Faculty of Eng. Nnamdi Azikiwe University Awka Anambra State 420001 Nigeria

The aim of this research is to determine the effect of bridging liquid surface tension and specific surface area on streng.h factor of coal agglomerates. The production of coal agglomerates of the range 15-27.51 mm was achieved. The crushing streng.h of the agglomerates was determined for good handling of fine （coal-liquid mixture） to improve fugitive dust control, decrease in transportation losses, reduce risk of coal freezing, lower risk of spontaneous combustion, etc. in iron and steel industries, railway corporations and coal corporations. Kerosene （paraffin oil） was used as a binder and the agglomerated coal oil mixture was pelletized using balling technique （disc）. mechanical and physical tests like compressive streng.h test, etc. were carried out. The relationship between the bridging liquid surface tension and specific surface area on streng.h factor of coal agglomerates showed that there is considerable variation in these parameters in the coal powder systems.

关键词： Sub-bituminous coal agglomerates breaking load crushing streng.h material handling.

加速管道流瞬态壁面摩擦阻力及湍流行为实验研究

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四川大学学报（工程科学版） 2012年第2期44卷 21-25页

作者：王峰 HE S ARIYARATNE C 四川大学建筑与环境学院四川成都610065 dept. of mechanical eng. Univ. of Sheffield Sheffield S1 3JD UK Thermo-Fluid mechanics Research Center Univ. of SussexBrighton BN1 9QTUK

通过对加速管道流瞬态壁面摩擦阻力及湍流行为的实验研究,并将改进的统计平均法应用于实验数据的处理。结果表明,加速管道流瞬态时均壁面切应力较稳态壁面切应力存在明显差异,工况1中最大差值接近于稳态值的2倍。流动加速率的降低和初... 详细信息

通过对加速管道流瞬态壁面摩擦阻力及湍流行为的实验研究,并将改进的统计平均法应用于实验数据的处理。结果表明,加速管道流瞬态时均壁面切应力较稳态壁面切应力存在明显差异,工况1中最大差值接近于稳态值的2倍。流动加速率的降低和初始流量的增加缩短了湍流的滞后段,减小了瞬态壁面切应力与稳态值的差别。瞬态壁面切应力及湍流的发展可分为4个典型阶段,前2个阶段为湍流的滞后期,流动惯性占据主导地位,后2个阶段为湍流的发展阶段。

关键词：加速管道流动壁面切应力湍流实验

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QUALITY AND TESTING IN RESISTANCE WELDING

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QUALITY AND TESTING IN RESISTANCE WELDING

第四届海内外青年设计与制造科学会议

作者： S.Jack Hu Jacek Senkara dept. of mechanical eng.neering and applied mechanics The University of Michigan Ann Arbor MI 48109 Welding Department Warsaw University of Technology Poland

＜正＞Because of a lack of scientific understanding of resistance spot weld quality,there is a tendency to overuse welds to fulfil design requirements of welded structures in the sheet metal welding ***,such practice faces serious challeng.s as more advanced materials are introduced and manufacturing processes get leaner and more *** this paper,quality and quality testing in resistance spot welding are *** quality related issues,such as materials,welding procedure and quality testing are *** quality is discussed based on a survey of various industries and professional *** process related issues,such as expulsion and defect formation,are discussed based on their influence on weld *** influence of quality testing procedures,which is often overlooked,is discussed in *** on the current status of weld quality research,it is found that a unified,scientifically developed,and universally accepted weld quality definition is the basis of controlling weld quality to meet design requirements of spot welds.

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2D vorticity and stream function solutions based on curvilinear coordinates

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2D vorticity and stream function solutions based on curvilin...

实验力学国际会议

作者： X.L.Xie W.W.Mar dept. of Mech. ＆ eng. Science Fudan Univ dept. of Basic Science Donghua Univ.

＜正＞ The governing equations of 2D vorticity ＆ stream function expanded in general curvilinear coordinates based on tensor calculus are attained. The numerical algorithms of covariant, anti-covariant metric tensor and Christoffel symbols of the first and second kinds are described in this paper. This method could be extended readily to arbitrary stream surfaces.

关键词： 2D vorticity & stream function curvilinear coordinates metric tensor Christoffel symbols anholonomic coordinate system

Computer Aided Thermal Stress Analysis of TBC Coated Specimen

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Journal of mechanics eng.neering and Automation 2011年第2期1卷 83-86页

作者： Yasar Kahraman Ibrahim Kutay Yilmazcoban Imdat Taymaz mechanical eng. Department Engineering Faculty and Sakarya University Sakarya 54187 Turkey

Thermal barrier coatings （TBC） have been improved for the eng.ne applications. During working process of the eng.ne, components were subjected to thermal stresses. For simulating thermally stressed eng.ne parts, disc specimen was objected to airflow at the temperatures about 1,000℃. In this study, finite element structural and thermal analyses were carried out on both uncoated （without coating） and ceramic-coated disc specimen using ANSYS code. A 150 micron super alloy bond coating （NiCrAIY） was first applied to the specimen. Then, the disc specimen was covered by 350 micron thickness of Mullit （3Al2O3.2SiO2） as a top coating. These analysis were performed for detecting the possible thermally problem areas. The disc＇s thermal stressed problematic areas were determined by the finite element analysis was helpful for improving the geometry and TBC.

关键词： Finite element analysis thermal barrier coating stresses.

The Effect of Curvature on the Slamming Force in Water Impact of a WIG Craft

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The Effect of Curvature on the Slamming Force in Water Impac...

The Fifth International Conference on Fluid mechanics

作者： A.Rastegari A.H.Nikseresht Student of Fluid mechanics Department of Mechanical Eng.Yasuj University

＜正＞Prediction of hydrodynamic loads during water impact is of great significance in the structural design of flying *** theoretical tool is available to handle this complicated phenomenon exactly,and the experimental procedures in the laboratory are both time-consuming and expensive. In this paper,numerical simulation of two phase flow in water impact problem of a WIG（Wing In Ground effect） is taken into account and the effect of changing the curvature of the step section of a WIG on the slamming force is investigated and the results are compared with a conventional wedge shape *** governing equations for unsteady two phase flow including continuity and momentum are solved using a finite volume discretized method code.

关键词： free-surface volume-of-fluid water impact concave convex

On Finite and Practical Stability of Time Delayed Systems:Lyapunov-Krassovski Approach,Delay Dependent Criteria

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On Finite and Practical Stability of Time Delayed Systems:Ly...

2011 Chinese Control and Decision Conference（CCDC）

作者： Dragutin LJ.Debeljkovi Ivan M.Buzurovi Tamara Nestorovi Dejan Popov University of Belgrade Faculty of Mechanical EngineeringDept.of Control Eng.11000 BelgradeSerbia Thomas Jefferson University Medical Physics DivisionPhiladelphiaPAUSA Ruhr-University of Bochum Dept.Mechanics of Adaptive SystemsGermany University of Belgrade Faculty of Mech.EngDept.of Control Eng.11000 BelgradeSerbia

This paper gives sufficient conditions for the practical and finite time stability of linear continuous time delay systems of the form X （t）=A0 x（t） + A1 x （t-τ）.When we consider finite time stability,these new,delay independent conditions are derived using the approach based on Lyapunov-Krassovski *** this case these functionals need not to have:a) properties of positivity in whole state space and b) negative derivatives along system *** we consider practical stability,before mentioned concept of stability,it is combined and supported by classical Lyapunov technique to guarantee attractivity properties of system behavior.

关键词： continuous singular time delay systems practical and finite time stability

Effects of Second Order Scattered Wave in Stratified Ocean

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Marine Science Bulletin 2001年第1期3卷 9-18页

作者：黄华詹杰民朱顶金廖德驹 dept. of applied mechanics and eng. Zhongshan University Guangzhou 510275 dept. of applied mechanics and eng. Zhongshan University Guangzhou 510275y using the theories on Stokes multicolored water waves and taking the two- layer ocean as a basic model of stratified ocean the paper analyzes the problems related to the effects of the nonlinear water wave on offshore structures. A mathematical expression is presented to describe second order wave radiation conditions. Using integral principle the analytical integral solutions are given to evaluate second order scattered wave loads on general vertical circular cylinders in the two-layer ocean and the special recurrence formulas for infinite integrals over free and stratified surfaces are derived.

By using the theories on Stokes multicolored water waves and taking the two- layer ocean as a basic model of stratified ocean, the paper analyzes the problems related to the effects of the nonlinear water wave on offshore structures. A mathematical expression is presented to describe second order wave radiation conditions. Using integral principle, the analytical integral solutions are given to evaluate second order scattered wave loads on general vertical circular cylinders in the two-layer ocean, and the special recurrence formulas for infinite integrals over free and stratified surfaces are derived.

关键词： Stratified ocean, second order wave, two layer ocean, scattering, diffracting, wave load

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荧光性微粒在气溶胶及微粒技术中应用的研究

化工学报 1983年第3期 246-256页

作者：王贤清,B. Y. H. Liu , D. Y. H. Pui 华东石油学院 Particle Technology Laboratory mechanical eng. dept. University of Minnesota Particle Technology Laboratory mechanical eng. dept. University of Minnesota Minneapolis U. S. A Minneapolis U. S. A

以荧色物作标记微粒是微粒技术研究中的一项新方法.荧色物具有很高的分析灵敏度,用通常的荧光光度比色仪,可将其浓度测至1×10-10g/ml;若采用Bergund-Liu气溶胶发生器,就可以得到已知直径及浓度的荧光性标准微粒,这对于研究微粒的空气... 详细信息

以荧色物作标记微粒是微粒技术研究中的一项新方法.荧色物具有很高的分析灵敏度,用通常的荧光光度比色仪,可将其浓度测至1×10-10g/ml;若采用Bergund-Liu气溶胶发生器,就可以得到已知直径及浓度的荧光性标准微粒,这对于研究微粒的空气动力学行为以及对于处理微粒状物料设备的标定是十分有效的.本文介绍了单分散气溶胶发生器,通过实验得出了使用荧光性微粒的一些重要条件,其中包括;溶剂的选择、微粒的发生与捕集、微粒中荧色物的提取及分析.文中还比较了两种常用的荧色物（荧光素钠及若丹明B）用于微粒技术的可能性,并应用这一技术对一种轴流式旋风分离器作了研究,得到了微粒在分离器各部位沉积情况的数据,它表明,该旋风分离器的分高效率和Stokes数间有一定的函数关系.

关键词：旋风分离器沙克龙分离设备荧光性微粒