检索结果-内蒙古大学图书馆

and CTOD-Based Tensile Strain Capacity Prediction for Pipelines With a Surface Crack in Girth Weld

Journal of Pressure Vessel technology 2022年第1期144卷 011305页

作者： Jang, Youn-Young Huh, Nam-Su Kim, Ik-Joong Kim, Young-Pyo Department of Mechanical System Design Engineering Seoul National University of Science and Technology 232 Gongneung-ro Nowon-gu Seoul 01811 South Korea Gas Infrastructure Research Division Korea Gas Corporation (KOGAS) Research Institute 1248 Suin-ro Sangnok-gu Ansan-City Gyeonggi-do 15328 South Korea

Long-distance pipelines for the transport of oil and natural gas to onshore facilities are mainly fabricated by girth welding, which has been considered as a weak location for cracking. Pipeline rupture due to crack initiation and propagation in girth welding is one of the main issues of structural integrity for a stable supply of energy resources. The crack assessment should be performed by comparing the crack driving force with fracture toughness to determine the critical point of fracture. For this reason, accurate estimation of the crack driving force for pipelines with a crack in girth weld is highly required. This paper gives the newly developed J-integral and crack-tip opening displacement (CTOD) estimation in a strain-based scheme for pipelines with an internal surface crack in girth weld under axial displacement and internal pressure. For this purpose, parametric finite element analyses have been systematically carried out for a set of pipe thicknesses, crack sizes, strain hardening, overmatch, and internal pressure conditions. Using the proposed solutions, tensile strain capacities (TSCs) were quantified by performing crack assessment based on crack initiation and ductile instability and compared with TSCs from curved wide plate tests to confirm their validity.

关键词： Pipes Pipelines J-integral crack-tip opening displacement pipelines Displacement girth weld strain-based design tensile strain capacity Fracture (Materials) Pressure Hardening Surface cracks Finite element analysis

来源：评论

学校读者我要写书评

暂无评论

Limit load estimation for finite plates with semi-elliptical defects under tensile loading

引用

Journal of Physics: Conference Series 2021年第1期1777卷

作者： K K Shi X L Fu H Xie X J Shao J Tian Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China

The ASME code allows the designer to circumvent many of the problems arising in design by elastic analysis by performing plastic or limit analysis of the component. Unlike elastic analysis, these analyses take account of the redistribution of stress upon yield. In limit analysis, the calculation of the limit load for finite plate with different semi-elliptical defects is an important stage for mechanical safety evaluation. The elastic compensation technique proposed by Mackenzie can be used to provide the limit load of a structure with a finite element method and aims at producing a suitable stress filed for the lower bound theory. In the present study, it is assumed that the finite plate exists three kinds of semi-elliptical cracks with low aspect ratio a/c (a/c=0.1, 0.5 and 1.0), respectively. The improved elastic compensation technique realized by finite element method is applied in the limit load estimation. At last, the results show that the improved elastic compensation technique can be used to obtain the limit value for the finite plate with different semi-elliptical defects under tensile loading. Moreover, the improved elastic compensation technique can be easily implemented in any finite element method and enables the limit load for any complex structure to be obtained swiftly.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Comparisons of Subgrid-Scale Models for OpenFoam Large- Eddy Simulation

引用

Journal of Physics: Conference Series 2021年第4期1802卷

作者： Zhipeng Feng Huanhuan Qi Xuan Huang Shuai Liu Jian Liu Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu Sichuan China

OpenFOAM is a free, open-source software package that can be used for the solutions of computational fluid dynamics and simulation of various fluid flow processes. Nevertheless, OpenFOAM still lacks default settings and a large number of different numerical schemes and turbulent models should be validated. In this paper, the unsteady flow around a cylinder (Re=3900) is calculated by the large eddy simulation of OpenFOAM. The predictions include the drag and lift coefficient, the pressure distribution around the cylinder, the velocity distribution and Reynolds stress distribution in the wake region, as well as the prediction of the recirculation length and separation angle. Thanks to several simulations, these five subgrid-scale (SGS) models are compared and studied: The Smagorinsky SGS model, wall adaptive local eddy visibility SGS model, dynamic SGS model with Lagrangian averaging, dynamic one equation eddy visibility model, one equation eddy visibility model. The numerical results are verified with the published experimental data.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Enhancing Irradiation Resistance in Refractory Medium Entropy Alloys with Simplified Chemistry

arXiv

引用

arXiv 2024年

作者： Tunes, M.A. Parkison, D. Sun, B. Willenshofer, P. Samberger, S. Derby, B.K. Baldwin, J.K.S. Fensin, S.J. Sobieraj, D. Wróbel, J.S. Byggmästar, J. Pogatscher, S. Martinez, E. Nguyen-Manh, D. El-Atwani, O. Chair of Non-Ferrous Metallurgy Montanuniversität Leoben Austria Materials Science and Technology Division Los Alamos National Laboratory United States Department of Nuclear Engineering University of California at Berkeley United States Departments of Mechanical Engineering and Materials Science and Engineering Clemson University United States Center for Integrated Nanotechnologies Los Alamos National Laboratory United States Faculty of Materials Science and Engineering Warsaw University of Technology Poland Department of Physics University of Helsinki Finland Materials Division United Kingdom Atomic Energy Authority Culham Campus Abingdon United Kingdom Department of Materials University of Oxford Parks Road United Kingdom Reactor Materials and Mechanical Design Pacific Northwest National Laboratory United States

Refractory High-Entropy Alloys (RHEAs) hold promising potential to be used as structural materials in future nuclear fusion reactors, where W and its alloys are currently leading candidates. Fusion materials must be able to withstand extreme conditions [1, 2], such as (i) severe radiation-damage arising from highly-energetic neutrons, (ii) embrittlement caused by implantation of H and He ions, and (iii) exposure to extreme high-temperatures and thermal gradients. Recent research demonstrated that two RHEAs - the WTaCrV [3] and WTaCrVHf [4] - can outperform both coarse-grained and nanocrystalline W in terms of its radiation response and microstructural stability [5-8]. Chemical complexity and nanocrystallinity enhance the radiation tolerance of these new RHEAs, but their multi-element nature, including low-melting Cr, complicates bulk fabrication and limits practical applications. Herein, we demonstrate that reducing the number of alloying elements and yet retain high-radiation tolerance is possible within the ternary system W-Ta-V via synthesis of two novel nanocrystalline refractory medium-entropy alloys (RMEAs): the W53Ta44V3 and W53Ta42V5 (in at.%). We experimentally show that the radiation response of the W-Ta-V system can be tailored by small additions of V, and such experimental result was validated with theoretical analysis of chemical short-range orders (CSRO) from combined ab-initio atomistic Monte-Carlo modeling. It is predicted from computational analysis that a small change in V concentration has a significant effect on the Ta-V CRSO between W53Ta44V3 and W53Ta42V5 leading to radiation-resistant microstructures in these RMEAs from chemistry stand-point of views. By returning to terminal solid solutions, we deviate from the original high-entropy alloy concept to show that high radiation resistance can be achieved in systems with simplified chemical complexity, hinting at a new paradigm for the metallurgy of high-entropy and highly-concentrated multi-compo

关键词： Tantalum alloys

来源：评论

学校读者我要写书评

暂无评论

Fluoride-Salt-Cooled High-Temperature reactor: An Integrated Nuclear-Based Energy Production and Conversion system

SSRN

引用

SSRN 2023年

作者： Zhang, Dalin Li, Xinyu Jiang, Dianqiang Zhou, Xingguang Lv, Xindi Yun, Shichang Wu, Wenqiang He, Xuanang Li, Haoyang Min, Xin Chen, Kailong Tian, Wenxi Qiu, Suizheng Su, G.H. Zhao, Quanbin Fu, Yao Tang, Chuntao Zhuo, Wenbin Li, Jinggang Zuo, Jiaxu State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai201800 China Shanghai Nuclear Engineering Research & Design Institute CO. LTD. Shanghai200233 China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Nuclear Power Institute of China Chengdu610213 China China Nuclear Power Technology Research Institute Guangdong Shenzhen518000 China Nuclear and Radiation Safety Center Ministry of Ecology and Environment People's Republic of China Beijing100082 China

Based on the analysis of energy structure and the development trends of advanced nuclear energy technology, combining the complementary advantages of nuclear energy and other energy sources in China, the Fluoride-salt-cooled High-temperature reactor(FuSTAR) system has been proposed. FuSTAR system is designed to address production capacity issues in areas with energy shortages or resource concentration and can be combined with high-temperature process heat to achieve high-value-added processes such as hydrogen production. In this paper, the Tri-structural isotropic fuel combined with helical cruciform elements has been studied in detail on the neutron physics and thermal-hydraulic properties, and the flow and heat transfer experiment is carried out for the first time. The multilayer nonlinear programming method has been applied to the design of thermal transport systems. Then the optimal parameters and configuration of the thermoelectric conversion system are obtained by the superstructure optimization method. The inherent safety of FuSTAR is demonstrated through deterministic safety analysis. In addition, the iodine-sulfur cycle technology and the characteristics of tritium production are also analyzed. This study highlights the significant potential of integrating nuclear energy with other energy sources in an optimized energy-production system. © 2023, The Authors. All rights reserved.

关键词： Nonlinear programming

来源：评论

学校读者我要写书评

暂无评论

Deep Learning-Based Compensation Mechanism for UAV Sensing via OTFS Signaling

引用

IEEE Internet of Things Journal 2025年

作者： Yan, Ziyu Yuan, Weijie Zhang, Xiaoqi Liu, Chang Wu, Jun Quek, Tony Q. S. Southern University of Science and Technology Department of Electrical and Electronic Engineering Shenzhen518055 China Southern University of Science and Technology School of System Design and Intelligent Manufacturing Shenzhen518055 China University of Technology Sydney Global Big Data Technologies Centre SydneyNSW2007 Australia La Trobe University Department of Computer Science and Information Technology MelbourneVIC3086 Australia Singapore University of Technology and Design 487372 Singapore Kyung Hee University Department of Electronic Engineering Yongin17104 Korea Republic of

Orthogonal Time Frequency Space (OTFS) modulation technology which provides reliable communication and precise sensing in high-mobility scenarios, has emerged as a potential solution for various unmanned aerial vehicle (UAV)-related applications. In this paper, we consider an OTFS communication waveform-based UAV sensing situation. Due to random wind gusts and varying weather conditions, the sensing signals may experience sudden disturbances. To effectively address this challenge, we propose a deep learning (DL)-based framework to compensate the impulse interference, which leverages empirical information and generates real-time predictions to achieve accurate UAV sensing. Specifically, we develop a prediction-assisted estimation network (PAEnet) to implement the proposed framework. The core component of PAEnet, the estimation network (ESnet), is capable to directly extract fractional delay and Doppler from the transmitted OTFS frame, thereby reducing the complexity of the sensing process. Through comprehensive simulation results, we demonstrate the effectiveness of the compensation mechanism in unreliable sensing scenarios, while showcasing the PAEnet’s capability to achieve superior accuracy for OTFS-based UAV sensing. © 2014 IEEE.

关键词： Signaling

来源：评论

学校读者我要写书评

暂无评论

Demonstration of a low loss, highly stable and re-useable edge coupler for high heralding efficiency and low g2(0) SOI correlated photon pair sources

arXiv

引用

arXiv 2023年

作者： Du, Jinyi Chen, George F.R. Gao, Hongwei Grieve, James A. Tan, Dawn T.H. Ling, Alexander Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 117543 Singapore Photonics Devices and System Group Singapore University of Technology and Design 8 Somapah Rd Singapore487372 Singapore Institute of Microelectronics A*STAR 2 Fusionopolis Way #08-02 Innovis Tower Singapore138634 Singapore Quantum Research Centre Technology Innovation Institute Abu Dhabi United Arab Emirates Department of Physics National University of Singapore Blk S12 2 Science Drive 3 117551 Singapore

We report a stable, low loss method for coupling light from silicon-on-insulator (SOI) photonic chips into optical fibers. The technique is realized using an on-chip tapered waveguide and a cleaved small core optical fiber. The on-chip taper is monolithic and does not require a patterned cladding, thus simplifying the chip fabrication process. The optical fiber segment is composed of a centimeter-long small core fiber (UHNA7) which is spliced to SMF-28 fiber with less than -0.1 dB loss. We observe an overall coupling loss of -0.64 dB with this design. The chip edge and fiber tip can be butt coupled without damaging the on-chip taper or fiber. Friction between the surfaces maintains alignment leading to an observation of ±0.1 dB coupling fluctuation during a ten-day continuous measurement without use of any adhesive. This technique minimizes the potential for generating Raman noise in the fiber, and has good stability compared to coupling strategies based on longer UHNA fibers or fragile lensed fibers. We also applied the edge coupler on a correlated photon pair source and observed a raw coincidence count rate of 1.21 million cps and raw heralding efficiency of 21.3%. We achieved an auto correlation function g(2)H(0) as low as 0.0004 at the low pump power regime. © 2023, CC BY-NC-ND.

关键词： Efficiency

来源：评论

学校读者我要写书评

暂无评论

Characterization of molten 2LiF–BeF_2 salt impregnated into graphite matrix of fuel elements for thorium molten salt reactor

引用

Nuclear science and Techniques 2019年第5期30卷 32-39页

作者： Hong-Xia Xu Jun Lin Ya-Juan Zhong Zhi-Yong Zhu Yu Chen Jian-Dang Liu Bang-Jiao Ye Center for Thorium Molten Salt Reactor System Shanghai Institute of Applied PhysicsChinese Academy of Sciences State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China USTC

The impregnation behavior of molten 2LiF–BeF_2(FLiBe) salt into a graphite matrix of fuel elements for a solid fuel thorium molten salt reactor(TMSR-SF) at pressures varying from 0.4 to 1.0 MPa was studied by mercury intrusion, molten salt impregnation, X-ray diffraction, and scanning electron microscopy *** was found that the entrance pore diameter of the graphite matrix is less than 1.0 μm and the contact angle is about 135°. The threshold impregnation pressure was found to be around 0.6 MPa experimentally, consistent with the predicted value of 0.57 MPa by the Washburn equation. With the increase of pressure from 0.6 to 1.0 MPa, the average weight gain of the matrix increased from 3.05 to 10.48%,corresponding to an impregnation volume increase from 2.74 to 9.40%. The diffraction patterns of FLiBe are found in matrices with high impregnation pressures(0.8 MPa and1.0 MPa). The FLiBe with sizes varying from tens of nanometers to a micrometer mainly occupies the open pores in the graphite matrix. The graphite matrix could inhibit the impregnation of the molten salt in the TMSR-SF with a maximum operation pressure of less than 0.5 MPa.

关键词： Keywords Molten salt reactor FLiBe Impregnation Graphite matrix

来源：评论

学校读者我要写书评

暂无评论

A MIMO robust servo controller design method for omnidirectional automated guided vehicles using polynomial differential operator 5th

A MIMO robust servo controller design method for omnidirecti...

引用

5th International Conference on Advanced Engineering Theory and Applications, AETA 2018

作者： Nguyen, Van Lanh Kim, Sung Won Lee, Choong Hwan Kim, Dae Hwan Kim, Hak Kyeong Kim, Sang Bong Department of Mechanical Design Engineering Pukyong National University Busan608-739 Korea Republic of Department of Machine System Engineering Dongwon Institute of Science and Technology Yangsan50598 Korea Republic of

ISBN: (纸本)9783030149062

This paper proposes a MIMO robust servo controller design method for a three wheeled Omnidirectional Automated Guided Vehicles (OAGVs) with a disturbance to track desired references using a polynomial differential operator. The process for designing the proposed controller can be described as follows: Firstly, modeling of the MIMO three-wheeled OAGV are presented. Secondly, a new extended system is obtained by applying the polynomial differential operator to the state space model and the output velocity error vector. Thirdly, the proposed controller for the given plant is designed by using the pole assignment method. By applying an inverse polynomial differential operator, a servo compensator is obtained. Finally, in order to verify the effectiveness of the proposed controller, the numerical simulation results are shown. The simulation results show that the proposed controller has good tracking performance under a step type of disturbance and the complicated higher order reference signals such as ramp and parabola. These simulation results are compared with those of the adaptive controller proposed by Bui, T. L. in 2013. The proposed controller shows the better tracking performance than the adaptive controller. © Springer Nature Switzerland AG 2020.

关键词： Controllers

来源：评论

学校读者我要写书评

暂无评论

Current redistribution model of anomalous resistance behaviour in superconductor-topological insulator heterostructures

arXiv

引用

arXiv 2022年

作者： Abhirami, S. Amaladass, Edward Prabu Sharma, Prashant Vinod, K. Thanikaiarasu, A.V. Mani, Awadhesh Materials Science Group Indira Gandhi Center for Atomic Research Tamil Nadu Kalpakkam603102 India Reactor Design and Technology Group Indira Gandhi Center for Atomic Research Tamil Nadu Kalpakkam603102 India Homi Bhabha National Institute Training school complex Anushaktinagar Mumbai400094 India

Anomalous resistance upturn and downturn have been observed on the topological insulator (TI) surface in superconductor-TI (NbN-Bi1.95Sb0.05Se3) heterostructures at ~ mm length scales away from the interface. Magnetotransport measurements were performed to verify that the anomaly is caused due to the superconducting transition of the NbN layer. The possibility of long range superconducting proximity effect due to the spin-polarized TI surface state was ruled out due to the observation of similar anomaly in NbN-Au and NbN-Al heterostructures. It was discovered that the unusual resistance jumps were caused due to current redistribution at the superconductor-TI interface on account of the geometry effects. Results obtained from finite element analysis using COMSOL package has validated the proposed current redistribution (CRD) model of long range resistance anomalies in superconductor-TI and superconductor-metal heterostructures. Copyright © 2022, The Authors. All rights reserved.

关键词： Electric insulators

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：