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Multi-Scale GHG Emission Relations in Resource-Based Heavy Industrial Cities: A Case Study of Tangshan City, Hebei Province

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Chinese Journal of Urban and Environmental Studies 2021年第4期9卷 74-98页

作者： HAN Mengyao JIANG Chuan LIU Siyuan Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Key Laboratory of Regional Sustainable Development Modeling Chinese Academy of Sciences School of Mechanical Engineering Yanshan University Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science (Ministry of Education of China)Yanshan University

The greenhouse gas(GHG) emission pressure faced by resource-based heavy industrial cities was mainly induced by multi-scale interactions, which require systematical assessments from local,regional, national and global scales. Taking Tangshan city, a heavy industry base in Hebei Province of China, as the research area, this study carried out a multi-scale analysis on the GHG emissions in terms of final demand, final consumption and trade balance. The main results are as follows:(1) The average embodied intensity of GHG emissions in Tangshan was 27.6 tons/10,000 CNY, of which 66.2% was caused by local inputs;(2) The secondary industry was the main source for the relatively high GHG emissions in Tangshan;(3) The GHG emissions embodied in final demand were 201.6 million tons, within which the proportion of fixed capital formation reached 59.4%;(4) As for the trade balance, Tangshan was a net exporter of embodied GHG emissions, with the total net outflows of 411.6 million tons. Depicting the GHG emission flows and sorting out the multiple GHG emission inventory would be helpful to identify the transformation pressure of resource-based heavy industry cities, which would be significant for the adjustments in industrial structures and policy optimization of energy saving and emissions reduction.

关键词： Resource-based heavy industry city embodied greenhouse gas emissions multi-scale input–output analysis

High-temperature fracture behavior of MnS inclusions based on GTN model

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Journal of Iron and Steel Research International 2019年第9期26卷 941-952页

作者： Xin-gang Liu Can Wang Qing-feng Deng Bao-feng Guo Key Laboratory of Advanced Forging and Stamping Technology and Science (Yanshan University) Ministry of Education of ChinaQinhuangdao 066004HebeiChina

The influence of the MnS plastic inclusion on the accumulation of internal damage was considered, and the Gurson– Tvergaard–Needleman (GTN) model was calibrated based on the finite element inverse method and image analysis method using ABAQUS and GTN models. The modified GTN damage model was used to simulate the initiation and propagation of cracks in an as-cast 304 stainless steel with MnS inclusions at 900 C. The simulation results agreed well with the experimental results, indicating that the model can be effectively applied to examine the high-temperature fracture behavior of MnS inclusions. The simulation and high-temperature tensile test results revealed that MnS inclusions increased the number of holes initiation and the probability of hole polymerization, reduced the crack propagation resistance, accelerated the occurrence of material fracture behavior, and were closely related to the stress state at high temperatures. When the stress triaxiality was low, the plastic strain in the metal matrix was high, and the MnS plastic inclusions accelerated the polymerization of the pores, making metal fracture failure more likely. On the other hand, when the stress triaxiality was high, the stress state in the metal matrix was biased to the tensile state, the plastic strain in the metal matrix was low, and the influence of MnS plastic inclusions on the fracture behavior was not evident.

关键词： MnS inclusion GTN model Tension High-temperature fracture behavior Crack initiation Crack propagation Stress

The High Magnetic-Field-Induced Thermodynamic Mechnism in the Interface between the Carbides and Martrix in Steel

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SSRN 2024年

作者： Zheng, Yihang Hou, Tingping Cheng, Shi Yang, Yuhao Zhang, Dong Zeng, Wenfeng Xiong, Wu Wu, Kaiming The State Key Laboratory of Refractories and Metallurgy Joint International Research Laboratory of Refractories and Metallurgy Hubei Province Key Laboratory of Systems Science on Metallurgical Processing International Research Institute for Steel Technology Collaborative Center on Advanced Steels Wuhan University of Science and Technology Wuhan430081 China Wuhan Heavy Industry Casting and Forging Co. Ltd Wuhan430081 China

The physical mechanism of the magnetic field-induced phase transition for M23C6/α-Fe was investigated utilizing a combination of high-resolution transmission electron microscopy (HRTEM) with Micromagnetic theory. The HRTEM results revealed that the M23C6/α-Fe interface exhibited a specific magnetic field-induced phase transition under the action of a high-temperature magnetic field, which increased the interface thickness between the carbide and matrix. Micromagnetic modeling establishes the relationship between the boundary thickness and the external magnetic field. The magnetization curves of carbide and matrix under high magnetic field are significantly shifted toward high temperature, which contributes to the reduction of the magnetic structure difference between M23C6 and α-Fe. The application of a strong magnetic field has a notable effect on the magnetization curve, shifting it towards higher temperatures. This diminishes the discrepancy in magnetic structure between M23C6 and α-Fe, leading to a substantial reduction in magnetostatic energy while concurrently augmenting magnetic exchange energy. Consequently, this process results in an increased thickness of the boundary between M23C6 and α-Fe. Combination of experiment and theory verifies the physical mechanism of the phase transition of carbides by magnetic field to provide a new theoretical basis for the formation of carbides by magnetic field. © 2024, The Authors. All rights reserved.

关键词： Carbides

Analytical and Experimental Studies of the Improved Conductance-Stability and Stretchability of the Liquid Metal-Embedded Composites Based on a Novel Continuous Annular-Shaped Branch Channels

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SSRN 2023年

作者： Li, Jing Wang, Xi Guo, Shu Chen, Shuang Luo, Yiwen Zhao, Shiyan School of Mechanical Engineering Hubei Modern Manufacturing Quality Engineering Key Laboratory Hubei University of Technology Hubei Wuhan430068 China School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Sichuan Chengdu611731 China School of Vehicle and Energy Yanshan University Hebei Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China

Stretchable and conductance-stable composites are critical for progress in flexible electronics. Tremendous efforts have focused on engineering electrical conductors from liquid metal-embedded elastomers. While these elastomers enable elastic compliance and deformability, the embedded liquid metal is vulnerable to puncture that cause undesired electrical failure, and most of the conductive elastomers are strain sensitive with degenerative conductance upon deformations. Here, we combined analytical and numerical analyses with experimental studies to investigate effects of the innovatively designed continuous annular-shaped branch channels, inspired by the Tesla valve, on the performances of the LM-embedded conductive composite. Theoretically, in the process of mechanical deformations, the as-proposed continuous annular-shaped architecture can dissipate the pressure energy of the fluidic LM to enhance the fracture toughness of the composite, while the LM flow could be accelerated as the deformation was removed to maintain the percolated conductive path, leading to excellent conductive stability. Experimentally, the as-fabricated composite conductor with continuous annular-shaped branch channels can be stretched up to ~80% (more than two times higher than conventional LM-embedded composite), and upon fully activating the conductive pathway, a very high conductivity of ~4×104 S·m-1 and conductance change of less than 2% under varied deformations, including stretching, flexing, twisting and compressing, are realized. It is believed that this novel design strategy will extend the understanding and application opportunities of LM as functional materials in the development of flexible electronics. © 2023, The Authors. All rights reserved.

关键词： Liquid metals

A Stretchable and Conductance-Stable Composite Based on a Liquid Metal-Embedded Elastomer with Continuous Annular-Shaped Branch Channels

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SSRN 2023年

作者： Li, Jing Chen, Shuang Guo, Shu Luo, Yiwen Zheng, Zhong Li, Xiuhong Zhao, Shiyan School of Mechanical Engineering Hubei Modern Manufacturing Quality Engineering Key Laboratory Hubei University of Technology Hubei Wuhan430068 China School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Sichuan Chengdu611731 China School of Vehicle and Energy Yanshan University Hebei Qinhuangdao066004 China Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China

Stretchable and conductance-stable composites are critical for progress in flexible electronics. Tremendous efforts have focused on engineering electrical conductors from liquid metal-embedded elastomers. While these elastomers enable elastic compliance and deformability, the embedded liquid metal is vulnerable to puncture that cause undesired electrical failure, and most of the conductive elastomers are strain sensitive with degenerative conductance upon deformations. Here, we report a versatile and practical approach to prepare stretchable LM-embedded elastomeric conductors with continuous annular-shaped branch channels. In the process of mechanical deformations, the annular-shaped branch channels can dissipate the pressure energy of the fluidic LM to enhance the fracture toughness of the composite, while the LM flow could be accelerated as the deformation was removed to maintain the percolated conductive path, leading to excellent conductive stability. The as-proposed composite conductor can be stretched up to ~80% (two times higher than conventional LM-embedded composite), and upon fully activating the conductive pathway, a very high conductivity of ~4×104 S·m-1 and conductance change of less than 2% under varied deformations, including stretching, flexing, twisting and compressing, are realized. It is believed that this novel design strategy will extend the application opportunities of LM as functional materials in the development of flexible electronics. © 2023, The Authors. All rights reserved.

关键词： Liquid metals

A New Method for Type Synthesis of 2R1T and 2T1R 3-DOF Redundant Actuated Parallel Mechanisms with Closed Loop Units

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Chinese Journal of Mechanical Engineering 2020年第6期33卷 134-157页

作者： Yongquan Li Yang Zhang Lijie Zhang Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao066004China Key Laboratory of Advanced Forging&Stamping Technology and Science Ministry of Education of ChinaYanshan UniversityQinhuangdao066004China School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen518052China Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan UniversityQinhuangdao066004China

The current type synthesis of the redundant actuated parallel mechanisms is adding active-actuated kinematic branches on the basis of the traditional parallel mechanisms,or using screw theory to perform multiple getting intersection and union to complete type *** number of redundant parallel mechanisms obtained by these two methods is *** this paper,based on Grassmann line geometry and Atlas method,a novel and effective method for type synthesis of redundant actuated parallel mechanisms(PMs)with closed-loop units is ***,the degree of freedom(DOF)and constraint line graph of the moving platform are determined successively,and redundant lines are added in constraint line graph to obtain the redundant constraint line graph and their equivalent line graph,and a branch constraint allocation scheme is formulated based on the allocation ***,a scheme is selected and redundant lines are added in the branch chains DOF graph to construct the redundant actuated branch chains with closed-loop ***,the branch chains that meet the requirements of branch chains configuration criteria and F&C(degree of freedom&constraint)line graph are *** this paper,two types of 2 rotational and 1 translational(2R1T)redundant actuated parallel mechanisms and one type of 2 translational and 1 rotational(2T1R)redundant actuated parallel mechanisms with few branches and closed-loop units were taken as examples,and 238,92 and 15 new configurations were *** the mechanisms contain closed-loop units,and the mechanisms and the actuators both have good ***,all the mechanisms have excellent comprehensive performance,in which the two rotational DOFs of the moving platform of 2R1T redundant actuated parallel mechanism can be independently *** instantaneous analysis shows that all mechanisms are not instantaneous,which proves the feasibility and practicability of the method.

关键词： Redundant actuated Parallel mechanisms Type synthesis Atlas method Instantaneous analysis

Molecular Dynamics Simulation Analysis of the Indentation Hardness of Nano-Twinned Ni

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SSRN 2022年

作者： Zhang, Qin Zhou, Bingrao Wang, Wei Li, Rongbin Lv, Zhiqing Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Ministry of Education of China Qinhuangdao066004 China State Key Laboratory of Metastable Material Science and Technology Yanshan University Qinhuangdao066004 China Shanghai Engineering Research Center of Hot Manufacturing Shanghai Dianji University Shanghai200245 China

Molecular dynamics simulations were employed to perform the nanoindentation analysis of nanocrystalline nickel with different crystal structures (single-crystal, polycrystalline, and nano-twinned) and twin layer thicknesses under a spherical indenter. To understand the effects of crystal structure and twin spacing on nanoindentation responses, the crystal structure, dislocation, strain, indentation force, temperature, hardness, Young's modulus, and elastic recovery rate of the indentation region were analyzed. It was noticed that crystal structure and twin spacing had great influences on the mechanical properties and elastic recovery rate of the three types of nanocrystalline nickel. In the single-crystal structure, plastic deformation occurred mainly due to dislocations and slips. In the polycrystalline structure, plastic deformation occurred due to dislocation–grain boundary interactions, whereas in the nano-twinned structure, dislocation–grain boundary and dislocation–twin boundary interactions were the main reasons for plastic deformation. In the single-crystal structure, the hydrostatic pressure was distributed in a "V"-shape below the indenter. In the polycrystalline structure, atoms under the compressive stress were distributed below the indenter and at crystal boundaries. In the nano-twinned structure, atoms under the compressive stress were mainly distributed below the indenter. © 2022, The Authors. All rights reserved.

关键词： Nanoindentation

δ-phase precipitation regularity of cold-rolled fine-grained GH4169 alloy plate and its effect on mechanical properties

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Transactions of Nonferrous Metals Society of China 2020年第12期30卷 3287-3295页

作者： Hao XUE Jing-qi ZHAO Yong-kang LIU Chun-xiang ZHANG Jun-ting LUO Key Laboratory of Advanced Forging&Stamping Technology and Science of Ministry of Education Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

Cold rolling and heat-treatment were used for the grain refinement of GH4169 superalloy *** effects of cold rolling reduction ratio and heat-treatment time on the precipitatedδphase,and the effects ofδ-phase content and morphology on the mechanical properties of the GH4169 alloy plates,are *** results demonstrate that coldrolling can promote the precipitation of theδphase and its transformation from theδ-Ni3Nb phase to theδ-NbNi4 *** comprehensive properties of the alloy are better when the heat treatment time is 1 h,with 132 MPa increase in the tensile strength and only 2.9%decrease in the elongation relative to those of the original *** mechanical properties of the alloy are shown to change greatly with the change in theδ-phase morphology.

关键词： fine-grained GH4169 alloy cold rolling δphase mechanical properties

Process Optimization of A356 Aluminum Alloy Wheel Hub Fabricated by Low-Pressure Die Casting with Simulation and Experimental Coupling Methods

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SSRN 2023年

作者： Bi, Jiang Dong, Guojiang Zhang, Liping Ma, Shaozhong Zhang, Dongsheng Wang, Ji Li, Wen Xu, Zuo Li, Shide Starostenkov, Mikhail Dmitrievich Yanshan University China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao066004 China CITIC Daika Co. Ltd. Qinhuangdao066004 China Hebei Key Laboratory of Special Delivery Equipment Yanshan University Qinhuangdao066004 China State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao066004 China General Physics Department Altai State Technical University Leninst. 46 Barnaul656099 Russia

The aluminum alloy wheel hub is mainly produced by low-pressure die casting process (LPDC), which casting quality is related to the process parameters. In this paper, the LPDC process of the A356 alloy wheel hub was simulated by ProCAST software, and the forming quality of the wheel hub under different cooling processes has been studied. The result indicated that the liquid aluminum exhibited different solidification characteristics under three cooling processes of 300 L/min for 150 s, 400 L/min for 140 s and 500 L/min for 130 s, and the wheels showed a sequential solidification state under the condition of 400 L/min for 140 s. By comparing the tensile properties of the rim under 300 L/min for 150 s and 400 L/min for 140 s cooling processes, it was found that the latter had higher tensile strength and elongation, which were 178.9 MPa and 6.6%, respectively. The reduction of casting defects, microstructure refinement and uniform distribution of eutectic Si particles in the wheel hub are the main reasons for the improvement of mechanical properties. © 2023, The Authors. All rights reserved.

关键词： Microstructure