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23rd International Conference on Nuclear Engineering: Nuclear Power - Reliable Global Energy, ICONE 2015

作者： Deng, Xiao Deng, Li-Ping Huang, Wei Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9784888982566

Water-lubricated thrust bearing is one of the key parts in canned motor pump, for example, the RCP in AP1000, and it functions to balance axial loads. A calculation model which can handle all flow state lubrication performance for water-lubricated thrust bearing has been presented. The model first includes laminar and turbulent Reynolds' equation. Then to get continuous viscosity coefficients cross critical Reynolds number, a transition zone which ranges based on engineering experience is put up, through which Hermite interpolation is employed. The model is numerically solved in finite difference method with uniform grids. To accelerate the calculation process, multigrid method and line relaxation is adopted within the iteration procedure. A medium sized water-lubricated tilting pad thrust bearing is exampled to verify the calculation model. Results suggest that as rotating speed enlarges, lubrication state distribution of the thrust bearing gradually tends to turbulent lubrication from the intersection corner of pad outer diameter and pad inlet to the opposite, minimum water film thickness increases approximately linearly, maximum water film pressure has little change, meanwhile the friction power grows nearly in exponential law which could result in bad effect by yielding much more heat. Copyright © 2015 by JSME.

关键词： Iterative methods

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A unified leader-follower scheme for mobile robots with uncalibrated on-board camera

A unified leader-follower scheme for mobile robots with unca...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Dejun Guo Hesheng Wang Weidong Chen Ming Liu Zeyang Xia Kam K. Leang DARC (Design Automation Robotics & Control) Lab University of Utah Robotics Center Salt Lake City Utah USA State Key Laboratory of Robotics and System (HIT) Key Laboratory of System Control and Information Processing Ministry of Education of China Department of Automation Shanghai Jiao Tong University Shanghai China Department of Electronics and Computer Engineering Hong Kong University of Science and Technology Hong Kong China Institute of Biomedical and Health Engineering Chinese Academy of Sciences Shenzhen China

This paper studies the problem of image-based leader-follower formation control for mobile robots, where the controller is designed independently of the leader's motion. An adaptive control scheme, which is suitable for both omnidirectional and perspective cameras, is proposed. The proposed approach avoids the need for accurate calibration of the extrinsic parameters of the omnidirectional camera as well as the intrinsic and extrinsic parameters of perspective camera. Additionally, the coefficients of the plane where the feature point moves relative to the camera frame can be uncertain. These uncertain constant parameters are estimated using an adaptive estimator. Uniform Semi-global Practical Asymptotic Stability (USPAS) of the system is shown using the Lyapunov approach. Experimental results are presented to demonstrate the effectiveness of the proposed control scheme.

关键词： Cameras Robot vision systems Kinematics Mobile robots Calibration Automation

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CFD simulation of direct contact condensation phenomenon of vapor in subcooled water tank 23

CFD simulation of direct contact condensation phenomenon of ...

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23rd International Conference on Nuclear Engineering: Nuclear Power - Reliable Global Energy, ICONE 2015

作者： Ji, Yu Quan, Yan Zhang, Yining Zhang, Haochun Wang, Yahui Harbin Institute of Technology Harbin Heilongjiang China Science and Technology on Reactor System Design Technology Laboratory Chengdu Sichuan China

ISBN: (纸本)9784888982566

The direct contact condensation (DCC) is a significant phenomenon in nuclear reactor and its balance facilities, together with other chemical engineering systems. DCC occurs when the vapor is injected into the subcooled water, contacts and condenses on the interface directly. The DCC phenomenon accompanied with the heat transfer and mass transfer will result in the temperature and pressure fluctuations in the tank. This paper discusses the DCC in the subcooled water tank from the view of computation fluid dynamics. The numerical simulation was performed with the CFD software, Fluent, in which the direct contact condensation phenomenon was modeled with the Euler-Euler framework for two phases flow, and the evaporation & condensation model was adopted to simulate the mass transfer process. During the simulation process, the flow field and temperature field are derived. In addition, the shape and size of plume jet are also investigated. Copyright © 2015 by JSME.

关键词： Heat transfer

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An Algorithm for Global Path Planning and Multi-objective Optimization Using Cell Mapping

An Algorithm for Global Path Planning and Multi-objective Op...

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第十届全国动力学与控制学术会议

作者： XUE Yang XIONG Fu-rui SUN Jian-qiao Department of Mechanics Tianjin UniversityTianjin300350China Science and Technology on Reactor System Design Technology LaboratoryNuclear Power Institute of ChinaChengdu 610041China School of EngineeringUniversity of CaliforniaMercedCA 95343USA

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Multi-objective Optimization of Elastic Beams For Minimum Weight and Sound Radiation

Multi-objective Optimization of Elastic Beams For Minimum We...

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第十届全国动力学与控制学术会议

作者： Meng-xin He Fu-Rui Xiong Yousef Naranjani Qian Ding Jian-Qiao Sun Department of Mechanics Tianjin University Tianjin300072China Science and Technology on Reactor System Design Technology LaboratoryNuclear Power Institute of ChinaChengdu 610041China School of EngineeringUniversity of California MercedCA 95343USA

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Natural convective heat transfer from a heated slender vertical tube in a cylindrical tank 16

Natural convective heat transfer from a heated slender verti...

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16th International Topical Meeting on Nuclear reactor Thermal Hydraulics, NURETH 2015

作者： Xian, Lin Jiang, Guangming Yu, Hongxing Science and Technology on Reactor System Design Technology Laboratory Chengdu610041 China Nuclear Power Institute of China Chengdu610041 China

ISBN: (纸本)9781510811843

Natural convective heat transfer in enclosures is widely researched in extensive range of engineering application such as passive residual heat removal system (PRHRS) in nuclear plant, solar collectors and cooling of electronic equipment. After Fukushima incident, the application and researching of PRHRS have been gaining more and more attention. It still has no proper calculating tools to analyze natural convective heat transfer with large L/D ratio and high Rayleigh number in PRHRS. In this paper, based on some former natural convective heat transfer experiments, numerical simulations and scale analysis, the single phase natural convective heat transfer correlation from the vertical tube have been developed. Transient single phase natural convection heat transfer along vertical tube in a cylindrical enclosure has been investigated for water with widely used computational fluid dynamic (CFD) engineering program ANSYS CFX-12. The influence brought by different geometry of tube and mesh scales has been evaluated by the results of former experiments. The ratio of tube length to diameter is a dimensionless factor affects heat transfer rate. The evaluation of thermal stratification to natural convective heat transfer in enclosure has been studied. Numerical simulation covers large L/D and high Rayleigh number natural convection: 108RaL14. Based on the scale analysis of natural convection cylindrical boundary equations the new dimensionless group has been put forward contains L/D factor. The new natural convective heat transfer along the vertical single tube model has been build according to the former experiments1 results. After combining numerical simulation results, the new model covers the higher Rayleigh number range of natural convection.

关键词： Natural convection

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Using directional diffusion coefficients for nonlinear diffusion acceleration of the first order s n equations in near-void regions

Using directional diffusion coefficients for nonlinear diffu...

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2016 Transactions of the American Nuclear Society, ANS 2016

作者： Schunert, Sebastian Hammer, Hans Lou, Jijie Wang, Yaqi Ortensi, Javier Gleicher, Frederick Baker, Benjamin Dehart, Mark Martineau, Richard Idaho National Laboratory Nuclear Methods Development Idaho FallsID United States Department of Nuclear Engineering Texas A and M University College StationTX United States Idaho National Laboratory Reactor Physics Analysis and Design Idaho FallsID United States Idaho National Laboratory Nuclear Science and Technology Modeling and Simulation Idaho FallsID United States

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Study on Unbalance Magnetic Pull of the Motorized Spindle under Different Rotor Eccentricities

Study on Unbalance Magnetic Pull of the Motorized Spindle un...

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International Conference on Ubiquitous Robots and Ambient Intelligence

作者： Jin Wang Minqing Jing Hongwei Fan Heng Liu Bijia Shi Key Laboratory of Education Ministry for Modern Design & Rotor-bearing System School of Mechanical Engineering Xi'an University of Science and Technology

ISBN: (纸本)9781509008223

High-speed precision machining is one of the important development directions of modern machining technology, high-speed spindle system is widely used in high-speed machining, and motorized spindle is the main choice of the high-speed machine tool spindle. The electromagnetic force caused by rotor unbalance is one of main vibration sources of motorized spindle. Firstly, the research on the frequency spectrum characteristic of electromagnetic force under different rotor eccentricities is very necessary to suppress electromagnetic vibration. An electromagnetic finite element model was built for a motorized spindle based on Ansoft Maxwell in this paper. The electromagnetic force spectrum variation under the static and dynamic eccentricities is studied. The Unbalance Magnetic Pull (UMP) of the motorized spindle under different rotating speeds and different eccentricities are analysed. The results show that the motorized spindle with the static or dynamic eccentricity both produces new components in the electromagnetic force. Simultaneously, the eccentricity increase positively results in the increase of UMP amplitude. The UMP is constant under the rotor static eccentricity, which has a small impact on rotor vibration, while the frequency of UMP under the rotor dynamic eccentricity is the rotating frequency, which will increase the motorized spindle vibration. Finally, by the experiment the correctness of theoretical analysis and simulation are verified. This work provides a theoretical foundation for the fault diagnosis and dynamic balance of the motorized spindle.

关键词： Machine tool motorized spindle Unbalance Magnetic Pull (UMP) Rotor eccentricity Finite element analysis Frequency spectrum analysis

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Large eddy simulation of turbulent flow in the rod bundle with different spacer grids 23

Large eddy simulation of turbulent flow in the rod bundle wi...

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23rd International Conference on Nuclear Engineering: Nuclear Power - Reliable Global Energy, ICONE 2015

作者： Wei, Zonglan Yu, Zhang Liu, Songtao Science and Technology on Reactor System Design Technology Laboratory NPIC Chengdu Sichuan China Nuclear Power Design and Research Sub-Institute NPIC Chengdu Sichuan China

ISBN: (纸本)9784888982566

Large eddy simulation(LES) of the swirling flow in the rod bundle subchannels with spacer grids are presented. According to the rod bundle flow benchmark experiment, the 5×5 rod bundle with a split-type spacer grid is simulated by this transient simulation with a fine hybrid mesh. Mean velocity components, RMS (root mean square) velocity components and turbulent kinetic energy profiles at different locations downstream the mixing vanes are compared between the experiment and simulation results. LES results can reproduce the mixing turbulent flow velocity field well. We also have studied the influence of the mixing vanes' bending degree on the subchannel flow structures by using LES to simulate the 3×3 rod bundle with the typical PWR spacer grid. The mixing vanes' bending degree is modified to 35°and 40°based on the original spacer grid, whose mixing vanes' bending degree is 30°. The larger bending degree produces a stronger mean coolant mixing effect, while larger pressure loss and fluctuation come together with this effect. The increased pressure loss would generate additional flow resistance, and larger fluctuation of coolant flow would make the mixing effect unstable, as well as would cause flow-induced vibration and grid-to-rod fretting phenomena. The LES method is a viable tool to optimize the spacer grid design and provide transient flow field data for mechanical analysis. Copyright © 2015 by JSME.

关键词： Mixing

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The Blood Compatibility Challenge

SSRN

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SSRN 2019年

作者： Jaffer, Iqbal H. Weitz, Jeffrey I. Brash, John L. Horbett, Thomas A. Latour, Robert A. Tengvall, Pentti Gorbet, Maud Sperling, Claudia Maitz, Manfred F. Siedlecki, Christopher A. Werner, Carsten Sefton, Michael V. Maitz, Manfred F. Martins, M. Cristina L Grabow, Niels Matschegewski, Claudia Huang, Nan Chaikof, Elliot L. Barbosa, Mário A. Werner, Carsten Thrombosis and Atherosclerosis Research Institute McMaster University 237 Barton Street East HamiltonONL8L 2X2 Canada McMaster University HamiltonON Canada University of Washington SeattleWA United States Clemson University ClemsonSC United States Gothenburg University Gothenburg Sweden Department of System Design Engineering University of Waterloo WaterlooON Canada Institute Biofunctional Polymer Materials Max Bergmann Center of Biomaterials Leibniz-Institut für Polymerforschung Dresden e.V. Dresden Germany Department of Surgery The Pennsylvania State University College of Medicine Hershey PA17033 United States Department of Bioengineering The Pennsylvania State University College of Medicine Hershey PA17033 United States University of Toronto Institute Biofunctional Polymer Materials Max Bergmann Center of Biomaterials Leibniz-Institut für Polymerforschung Dresden e.V. Dresden Germany i3S Instituto de Investigacao e Inovacao em Saude INEB Instituto de Engenharia Bionedica Rua Alfredo Allen 208 Porto4200-135 Portugal ICBAS Instituto de Ciencias Bioedicas Abel Salazar Universidade do Porto Porto Portugal Institut für Biomedizinische Technik Universitätsmedizin Rostock Friedrich-Barnewitz-Str. 4 Rostock18119 Germany Key Laboratory of Advanced Technology for Materials of Education Ministry School of Materials Science and Engineering Southwest Jiaotong University Chengdu610031 China Beth Israel Deaconess Medical Center Harvard Medical School 330 Brookline Avenue BostonMA02115 United States Wyss Institute for Biologically Inspired Engineering Harvard University 3 Blackfan Circle BostonMA02115 United States Harvard-MIT Division of Health Sciences and Technology 77 Massachusetts Avenue CambridgeMA02139 United States

Despite >50 years of study, there are no materials that are considered truly nonthrombogenic. Some materials minimize protein adsorption or cell adhesion while others actively inhibit thrombin generation through heparinization. Nonetheless the problem of biomaterial associated thrombogenicity remains. While once an active area of research, the problem has not only not been solved, it has also been largely abandoned. It is considered too hard or efforts attack only one particular aspect of the problem or more broadly new ideas and approaches have not been brought to bear. This frustration has led to a series of review papers where we summarize the features of broad agreement and provide commentary on those aspects of the problem that were subject to dispute. These are (see also Figure 1): 1. Blood-contacting medical devices: The scope of the problem;2. Protein adsorption phenomena governing blood reactivity;3. Material associated activation of blood cascades and cells;4. Surface modification for hemocompatible materials: passive and active approaches to guide blood-material interactions. We were inspired by the structure of the >1500 year old book of Jewish laws, called the Talmud, in which commentaries are layered on commentaries to interpret and reinterpret a biblical law. It takes the form of a record of discussions pertaining to Jewish law, ethics, philosophy, customs and history. Here we began with what we believed to be a generally accepted truth regarding thrombogenicity and then added our thoughts and commentaries regarding with respect to aspects that were not as scientifically firm as the opening "truth." We hope that future investigators will update these reviews as new scholarship resolves the uncertainties of today. © 2019, The Authors. All rights reserved.

关键词： Cell adhesion

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