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Numerical Investigation of Flatback Airfoils Drag and Noise Reduction by a Splitter Plate

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Numerical Investigation of Flatback Airfoils Drag and Noise ...

作者： Ke Song School of Aeronautics Northwestern Polytechnical University National key laboratory of science and technology on aerodynamic design and research

In this paper the aerodynamic and aeroacoustic characteristics of a wind turbine airfoil have been numerically *** modified versions of TU Delft DU97-W-300 airfoil with a flatback trailing edge and a splitter plate were *** method was introduced and provided good results compared with the experimental data with regard to the *** analysis focused on the amplitude and frequency of noise associated with the vortex-shedding tone from the trailing edge *** results showed that wake flows were significantly effected by the addition of a splitter plate to the flatback trailing edge,and lead to reduction on both drag and noise.

关键词： Numerical Investigation of Flatback Airfoils Drag and Noise Reduction by a Splitter Plate

Janus-graphene: a two-dimensional half-auxetic carbon allotropes with non-chemical Janus configuration

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arXiv

arXiv 2023年

作者： Yu, Linfeng Xu, Jianhua Shen, Chen Zhang, Hongbin Zheng, Xiong Wang, Huiming Qin, Zhenzhen Qin, Guangzhao National Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China Institute of Materials Science Technical University of Darmstadt Darmstadt64287 Germany Hunan Key Laboratory for Micro-Nano Energy Materials & Device School of Physics and Optoelectronics Xiangtan University Hunan Xiangtan411105 China School of Physics and Microelectronics Zhengzhou University Zhengzhou450001 China Greater Bay Area Institute for Innovation Hunan University Guangdong Province Guangzhou511300 China

The asymmetric properties of Janus two-dimensional materials commonly depend on chemical effects, such as different atoms, elements, material types, etc. Herein, based on carbon gene recombination strategy, we identify an intrinsic non-chemical Janus configuration in a novel purely sp2 hybridized carbon monolayer, named as Janus-graphene. With the carbon gene of tetragonal, hexagonal, and octagonal rings, the spontaneous unilateral growth of carbon atoms drives the non-chemical Janus configuration in Janus-graphene, which is totally different from the chemical effect in common Janus materials such as MoSSe. A structure-independent half-auxetic behavior is mapped in Janus-graphene that the structure maintains expansion whether stretched or compressed, which lies in the key role of pz orbital. The unprecedented half-auxeticity in Janus-graphene extends intrinsic auxeticity into pure sp2 hybrid carbon configurations. With the unique half-auxeticity emerged in the non-chemical Janus configuration, Janus-graphene enriches the functional carbon family as a promising candidate for micro/nanoelectronic device applications. Copyright © 2023, The Authors. All rights reserved.

关键词： Graphene

Recycled Aggregate Concrete-Filled Steel Tube Columns with Small-Diameter Circular Frp-Confined Sea-Sand Concrete Cores: Conceptual and Experimental Investigations

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SSRN 2023年

作者： Zeng, Lan Wu, Liqi Li, Boqin Fang, Shu Mohamed, Hazem Samih Fang, Zhuangcheng Yuan, Hong MOE Key Laboratory of Disaster Forecast and Control in Engineering School of Mechanics and Construction Engineering Jinan University Guangdong Guangzhou510632 China Guangdong Architectural Design and Research Institute Co. Ltd. Guangzhou510006 China Guangdong Key Laboratory of Earthquake Engineering & Applied Technique Earthquake Engineering Research & Test Centre Guangzhou University Guangzhou510006 China School of Architectural Engineering Guangzhou Institute of Science and Technology Guangzhou510540 China Fujian Agriculture and Forestry University China

Recycled aggregate concrete (RAC) prepared from waste concrete can achieve the green recycling of resources;however, its inferior material properties hinder its applications. Sea-sand concrete (SSC) can help alleviate the resource shortage of fresh water and river sands but is prone to steel corrosion. To address these challenges, this study developed a new RAC-filled steel tube column with a small-diameter circular fibre-reinforced polymer (FRP)-confined SSC core. This paper presents and discusses the results of the axial compression tests conducted on RAC-filled steel tube columns, with and without small-diameter circular FRP-confined SSC cores. The study investigated the effects of the configuration of the FRP-confined SSC core, diameter-to-thickness ratio of the FRP tubes, compressive strength of RAC and SSC, and cross-sectional shape of the column. The results revealed that using small-diameter circular FRP-confined SSC cores to partially replace RAC was effective in improving the compressive performance of RAC-filled steel tube columns. The increase in the number of FRP tubes, in-filled concrete strength, and confinement stiffness of the steel and FRP tubes contributed to improvements in the structural strength and ductility, resulting in progressive ladder-shaped declines in the post-peak curve. Finally, a reasonable load–capacity model is presented for the proposed columns. © 2023, The Authors. All rights reserved.

关键词： Steel corrosion

A Comprehensive Modelling Framework of Soft Mre: Magnetic Stiffening Effect and Magnetic Dependent Nonlinear Viscoelasticity

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SSRN 2022年

作者： Gong, Xinglong Wang, Bochao Bustamante, Roger Kari, Leif Pang, Haoming Key Laboratory of Mechanical Behaviour and Design of Materials Department of Modern Mechanics University of Science and Technology of China Hefei230027 China Departamento de Ingeniería Mecánica Universidad de Chile Beauchef 851 Santiago Centro Santiago Chile Department of Engineering Mechanics KTH Royal Institute of Technology Stockholm10044 Sweden Anhui Weiwei Rubber Part Group Co. Ltd.„ Tongcheng 231460 China

Soft magneto-rheological elastomers (s-MRE) are polymer-based composites fabricated by embedding magnetically soft particles into an elatomer matrix, with a stong stiffness tunability and a magnetostrictive behaviour under a magnetic field, offering a wide application potential in vibration control, soft robotics and haptic displays. Much theoretical work has focused on the modelling of the magnetostriction of s-MRE, but, currently, there is no theory that fully considers the magnetic stiffening effect and the magnetic-dependent nonlinear viscoelasticity of s-MRE. However, as essential components of the observed magneto-mechanical coupled response, they are crucial for the application of s-MRE. For example, the vibration control effect of MRE-based isolator and the response time and sensitivity of MRE-based soft robotics are closely related to the magnetic stiffening effect and the magnetic-dependent nonlinear viscoelasticity of s-MRE. In order to predict these behaviours accurately and to provide guidance to the design of s-MRE-based applications, herein, a comprehensive modelling framework that incorporates the magnetic stiffening and the magnetic-dependent nonlinear viscoelasticity of s-MRE is proposed. Firstly, a viscosity evolution law that ascertains the relation among the viscoelastic stress, magnetic field and the viscous strain rate is determined through experimental study and theoretical analysis. Subsequently, the corresponding constitutive model and the numerical implementation algorithm for the isotropic and anisotropic s-MRE is developed. After model validation, the model is implemented in a finite-element framework. Finally, four set of case studies are performed to illustrate the feasibility of the model-based simulation to guide the design of s-MRE-related applications. © 2022, The Authors. All rights reserved.

关键词： Vibration control

A Review on Binderless Tungsten Carbide: Development and Application

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Nano-Micro Letters 2020年第1期12卷 158-194页

作者： Jialin Sun Jun Zhao Zhifu Huang Ke Yan Xuehui Shen Jiandong Xing Yimin Gao Yongxin Jian Hejie Yang Bo Li State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE School of Mechanical EngineeringShandong UniversityJinan 250061People’s Republic of China Key Laboratory of Education Ministry for Modern Design and Rotor‑Bearing System Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China School of Mechanical and Automotive Engineering Qilu University of TechnologyJinan 250353People’s Republic of China

WC-Co alloys have enjoyed great practical significance owing to their excellent properties during the past *** the advantages,however,recently there have been concerns about the challenges associated with the use of Co,*** instability,toxicity and properties degeneration,which necessitates the fabrication of binderless tungsten carbide(BTC).On the other hand,BTC or BTC composites,none of them,to date has been commercialized and produced on an industrial scale,but only used to a limited extent for specialized applications,such as mechanical seals undergoing high burthen as well as high temperature electrical *** are two challenges in developing BTC:fully densifying the sintered body together with achieving a high ***,this review applies towards comprehensively summarize the current knowledge of sintering behavior,microstructure,and mechanical properties of BTC,highlighting the densification improving strategies as well as toughening methods,so as to provide reference for those who would like to enhance the performance of BTC with better reliability advancing them to further wide applications and prepare the material in a way that is environment friendly,harmless to human health and low in production *** paper shows that the fabrication of highly dense and high-performance BTC is economically and technically *** properties of BTC can be tailored by judiciously selecting the chemical composition coupled with taking into careful account the effects of processing techniques and parameters.

关键词： Binderless tungsten carbide Sintering Densification Toughening Mechanical properties

Microstructure, Mechanical Properties and Strengthening Mechanism of Tib2 Nanoparticles-Reinforced Cocrfemnni High-Entropy Alloy

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SSRN 2023年

作者： Chen, Zhao Wen, Xiaoli Wang, Weili Lin, Xin Yang, Haiou Jiang, Ze Chen, Lianyang Wu, Haibin Li, Wenhui Li, Nan School of Physical Science and Technology Northwestern Polytechnical University 127 Youyixilu Shaanxi Xi’an710072 China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT China Northwestern Polytechnical University 127 Youyixilu Shaanxi Xi’an710072 China School of Materials and Energy Electron Microscopy Centre of Lanzhou University Key Laboratory of Magnetism and Magnetic Materials Ministry of Education Lanzhou University Lanzhou730000 China School of Aeronautics Northwestern Polytechnical University 127 Youyixilu Shaanxi Xi’an710072 China State Key Laboratory of Solidification Processing China

TiB2 nano-particle reinforced CoCrFeNiMn composite has been additively manufactured by using selective laser melting (SLM) technique. In comparison with matrix CoCrFeNiMn sample, the average grain size of the TiB2 doped CoCrFeNiMn (CoCrFeNiMn+TiB2) sample reduces from 26.27 μm to 7.51 μm, appearing a morphological transformation from columnar grains to fine equiaxed grains and fine dendritic grains. Correspondingly, the compressive yield strength (σy) sharply increases from 484.41 ± 57.81 MPa of CrFeMnNi HEA to 952.62 ± 38.15 MPa of CoCrFeNiMn+TiB2, revealing a substantial enhancement of mechanical properties. Structural analysis unveils that the CoCrFeMnNi+TiB2 sample formed tetragonal σ phase beside FCC matrix and TiB2 phases compared with the single FCC phase of CoCrFeMnNi HEA. Atomic resolution scanning transmission electron microscopy discloses that the TiB2 nanoparticles expitaxially grow onto the FCC matrix phase with [01-10]TiB2 // [011]FCC orientation relationship. Theoretical calculations indicate that the enhancement mechanism of the CoCrFeMnNi+TiB2 sample should originate from a synergistic strengthening effect which is induced by grain refinement, TiB2 particles, σ phases and dislocations. Our work should provide a new view to utilize the rapid solidification process of SLM and ceramic nano-particle reinforcement for the enhanced mechanical properties of HEAs with great potential. © 2023, The Authors. All rights reserved.

关键词： Iron alloys

Neutron physical feasibility of small modular design of dual fluid reactor 27

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Neutron physical feasibility of small modular design of dual...

27th International Conference on Nuclear Engineering: Nuclear Power Saves the World!, ICONE 2019

作者： Wang, Xiang Zhang, Qian He, Xun Du, Zhuoqi Seidl, Marcus Macian-Juan, Rafael Czerski, Konrad Dabrowski, Mariusz College of Nuclear Science and Technology Harbin Engineering University Harbin Heilongjiang China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China Institute of Nuclear Engineering Technical University of Munich Garching Bayern Germany Faculty of Mathematics and Physics University of Szczecin Szczecin Poland

ISBN: (纸本)9784888983051

The Dual Fluid reactor (DFR) is a fast reactor concept proposed by the Institute of Solid-state- and Nuclear physics (IFK) in Berlin. The design of DFR aims to combine the Gen-IV Molten Salt reactor (MSR) and the Liquid-Metal Cooled reactor (SFR, LFR), which means that the molten-salt fuel is no more used as coolant while the heat is removed in a separate loop by liquid lead, to improve these two concepts. Without control rods, DFR is given hope to react and take steps to the change of operation conditions automatically by its inertial negative temperature feedback. Since fuel and coolant are both liquid, the circulation speed of each liquid is considered capable to adjust operational parameters for DFR. The original design of a 3000MWth (Wang, 2017) and a downscaled version of 500MWth (He, 2016) were analyzed in the aspects of reactor physics and thermal-hydraulics. For the practical purpose, this paper has proposed a small modular version of the DFR, which has power output of 2MWth. The reactor with such power level is expected in various applications. Therefore, it is necessary to perform the more explicit analysis on the design than the previous ones. The analysis focuses on the neutronic calculations with the default fuel salt of U-Pu mixture under steady state conditions. Copyright © 2018-2019 by JSME

关键词： Coolants

Effect of Background Magnetic Field on Quench Properties in Rebco and Bi-2223 Tapes

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SSRN 2022年

作者： Qiu, T. Zhu, Y.P. Hu, X.B. Liu, Jian Cai, Lijun Xu, M. Zhang, S.N. Feng, J.Q. Tan, Yunfei Yang, Xinsheng Zhao, Y. CRSC Research & Design Institute Group Co. Ltd. Beijing100071 China Superconductivity and New Energy R&D Center Southwest Jiaotong University Chengdu610031 China Southwestern Institute of Physics Chengdu610041 China Northwest Institute for Nonferrous Metal Research Xi’an710016 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan430074 China

Quench propagation characteristics are very important for high temperature superconductor (HTS). In this paper, quench properties including the minimum quench energy (MQE) and the normal zone propagation velocity (NZPV) in different HTS tapes (REBCO and Bi-2223) under different value and position of background magnetic field were investigated. After applying a heat pulse to REBCO and Bi-2223 tapes, the electric field of each zone was measured to obtain the parameters characterizing MQE and NZPV. The experimental results show that the MQE and NZPV are different with different background magnetic field position for the same kind tape. At the position of heater, the magnetic field will also have an impact on the MQE. The equivalent heat capacity of the two tapes was calculated respectively. It was found that the equivalent heat capacity of Bi-2223 tape is larger than REBCO tape. According to formula derivation, the larger the equivalent heat capacity, the larger the MQE and the smaller NZPV. © 2022, The Authors. All rights reserved.

关键词： High temperature superconductors

Thermal stress analysis of printed circuit heat exchanger based on thermal-structural coupling method

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Thermal stress analysis of printed circuit heat exchanger ba...

2019 International Conference on Boilers and Heat Exchangers, ICBHE 2019

作者： Wu, Jun Yao, Shuo Zhao, Zhenxing Xiao, Qi Ke, Zhiwu Lin, Yuansheng Science and Technology on Thermal Energy and Power Laboratory Wuhan Second Ship Design and Research Institute Hubei Province Wuhan430205 China School of Energy and Power Engineering Xi'An Jiaotong University Xi'an Shaanxi Province710049 China

The supercritical carbon dioxide (S-CO2) Brayton cycle has the advantages of high efficiency, compactness and simplicity. It is expected to become the main technical route for the future advanced ship nuclear power platform. The printed circuit heat exchanger (PCHE) with ultra-high pressure, ultra-compact and ultra-high efficiency typical characteristics is the ideal configuration of the S-CO2 power generation system recuperator. The PCHE numerical analysis model is constructed and the thermal stress field of the PCHE core structure is analyzed by thermal-structural coupling method. The results show that the maximum thermal stress of the PCHE core structure is 117 MPa, which is less than the yield limit of the material and meets the requirement of strength safety. The thermal stress value of most regions in PCHE is less than 78.2MPa. Therefore, the current design scheme has a large safety margin. The PCHE compactness can be further improved by structural parameter optimization. © Published under licence by IOP Publishing Ltd.

关键词： Structural optimization