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Reduction behavior of iron ore powder by high-volatile coal in thermogravimetric-gas chromatographic and kinetic analysis

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Journal of Iron and Steel Research International 2024年第1期31卷 92-107页

作者： Rui-meng Shi Qi-yuan Mi Bin Li Xiao Shi Chong Zou Jing Guo Han-jie Guo School of Metallurgical engineering Xi’an University of Architecture and TechnologyXi’an710055ShaanxiChina China International engineering consulting Corporation Beijing100048China School of Metallurgical and Ecological engineering University of Science and Technology BeijingBeijing100083China

The reduction behavior of iron ore powder by high-volatile coal was investigated,and its kinetic mechanism was *** effect of volatiles in coal on the reduction reaction of iron ore was compared by utilizing a Xinjiang lignite with a high volatile content and its pyrolysis carbon produced by high-temperature pyrolysis to remove volatiles,serving as a *** mass loss and gas composition of the samples during the reduction process were detected using thermo-gravimetric analysis and gas chromatography,and the morphological changes of iron ore powder were observed through scanning electron *** kinetic parameters of the iron oxide reduction reaction were calculated by the Flynn-Ozawa-Wall method,and the kinetic mechanism of volatile participation in the iron oxide reduction reaction was determined through the Coats-Redfern *** results indicate that the coupling effect between the high-volatile coal pyrolysis and reduction reactions occurs during the second stage of the entire coupling process,which corresponds to the late stage of coal pyrolysis with a substantial release of H_(2)and *** volatiles in coal actively participated in the reduction reaction,reducing the initiation temperature of the reaction by around 200℃.The reduction of iron oxides by high-volatile coal was jointly promoted by the"hydrogen cycle"and"carbon cycle",resulting in a higher reduction extent and metallization rate at the end of the *** high-volatile coal was used as the reductant,the average activation energy for the entire process was 76.5 kJ/mol,a significant decrease compared to the employment of pyrolysis carbon without volatiles as the reductant(1167 kJ/mol).

关键词： Direct reduction High-volatile coal Volatile Kinetics Reduction mechanism

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Deformation characteristics of ultra-deep circular shaft in soft soil:A case study

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Underground Space 2024年第3期16卷 239-260页

作者： Yafei Qiao Feng Xie Zhanwei Bai Jiafeng Lu Wenqi Ding Department of Geotechnical engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground engineering of Ministry of Education Tongji UniversityShanghai 200092China engineering Project Management Company Shanghai Chengtou Water GroupShanghai 200002China SGIDI engineering consulting(Group)Co. Ltd.Shanghai 200093China

A circular shaft is often used to access a working well for deep underground space *** the depth of underground space increases,the excavation depth of the shaft *** this study,the deformation characteristics of a circular shaft with a depth of 56.3 m were presented and *** main monitoring contents included:(1)wall deflection;(2)vertical wall movement;(3)horizontal soil movement;(4)vertical surface movement;and(5)basal ***,the maximum wall deflection was only 7.7 *** with the wall deflection data collected for another 29 circular excavations,the ratio of maximum wall deflection to excavation depth of this shaft was smaller due to a smaller ratio of diameter to excavation *** wall deflection underwent two stages of deformation:the first stage was mainly circumferential compression caused by the mutual extrusion of joints between walls,and the second stage was typical vertical deflection *** horizontal soil movement outside the shaft was greater than the wall deflection and the deep soil caused great horizontal movement because of dewatering at confined water ***,a basal heave of 203.8 mm occurred in the pit centre near the ***,the shaft was uplifted over time and showed 3 stages of vertical *** surface outside the shaft exhibited settlement and uplift deformation at different locations due to different *** basal heave caused by excavation was the dominant factor,driving the vertical movement of the shaft as well as the surrounding *** correlation between the wall deflection and the surface settlement outside the shaft was weak.

关键词： Circular shaft Site monitoring Deflection Vertical deformation Soft soil

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Vibration and noise mechanism of a 110 kV transformer under DC bias based on finite element method

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Global Energy Interconnection 2024年第4期7卷 503-512页

作者： Ziyang Li Xujun Lang Bo Yang Xiaolin Liu Hao Wang Zhang Li Shandong Electric Power engineering consulting Institute Co. Ltd.Jinan 250013P.R.China School of Electrical engineering Shandong UniversityJinan 250061P.R.China

Global energy and environmental issues are becoming increasingly problematic,and the vibration and noise problem of 110 kV transformers,which are the most widely distributed,have attracted widespread attention from both inside and outside the *** bias is one of the main contributing factors to vibration noise during the normal operation of *** clarify the vibration and noise mechanism of a 110 kV transformer under a DC bias,a multi-field coupling model of a 110 kV transformer was established using the finite element *** electromagnetic,vibration,and noise characteristics during the DC bias process were compared and quantified through field circuit coupling in parallel with the power frequency of AC,harmonic,and DC power *** was found that a DC bias can cause significant distortions in the magnetic flux density,force,and displacement distributions of the core and *** contributions of the DC bias effect to the core and winding are different at Kdc=*** this point,the core approached saturation,and the increase in the core force and displacement ***,the saturation of the core increased the leakage flux,and the stress and displacement of the winding increased *** sound field distribution characteristics of the 110 kV transformer under a DC bias are related to the force *** the DC bias coefficient was 1.25,the noise sound pressure level reached 73.6 dB.

关键词： Transformer DC bias Vibration Noise

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A Wind Power Prediction Framework for Distributed Power Grids

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Energy engineering 2024年第5期121卷 1291-1307页

作者： Bin Chen Ziyang Li Shipeng Li Qingzhou Zhao Xingdou Liu Power Grid Design Institute Shandong Electric Power Engineering Consulting Institute Co.Ltd.Jinan250013China School of Electrical engineering Shandong UniversityJinan250012China

To reduce carbon emissions,clean energy is being integrated into the power *** power is connected to the grid in a distributed form,but its high variability poses a challenge to grid *** article combines wind turbine monitoring data with numerical weather prediction(NWP)data to create a suitable wind power prediction framework for distributed ***,high-precision NWP of the turbine range is achieved using weather research and forecasting models(WRF),and Kriging interpolation locates predicted meteorological data at the turbine ***,a preliminary predicted power series is obtained based on the fan’s wind speed-power conversion curve,and historical power is reconstructed using variational mode decomposition(VMD)filtering to form input variables in chronological ***,input variables of a single turbine enter the temporal convolutional network(TCN)to complete initial feature extraction,and then integrate the outputs of all TCN layers using Long Short Term Memory Networks(LSTM)to obtain power prediction sequences for all turbine *** proposed method was tested on a wind farm connected to a distributed power grid,and the results showed it to be superior to existing typical methods.

关键词： Wind power prediction distributed power grid WRF mode deep learning variational mode decomposition

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Composition design and performance evaluation of rubber-particle cement-stabilized gravel

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Frontiers of Structural and Civil engineering 2024年第9期18卷 1466-1477页

作者： Chaohui WANG Ke YI Feng CHEN Luqing LIU Xiaolei ZHOU Zhiwei GAO School of Highway Chang’an UniversityXi’an 710064China Shaanxi Transportation Technology consulting Co. Ltd.Xi’an 710068China School of Information engineering Xizang Minzu UniversityXianyang 71208China

To improve the mechanical properties and durability of the cement-stabilized base,rubber particles of three different sizes and with three different contents were optimally selected,the evolution laws of the mechanical strength and toughness of rubber-particle cement-stabilized gravel(RCSG)under different schemes were determined,and the optimal particle size and content of rubber particles were *** this basis,the durability of the RCSG base was *** results show that with an increase in the rubber particle size and content,the mechanical strength of RCSG gradually decreased,whereas the toughness and transverse deformation ability gradually increased.1%content and 2–4 mm sized RCSG can better balance the relationship between mechanical strength and *** 7 d unconfined compressive strength was 17.7%higher than that of the 4–8 mm *** 28 d toughness index and ultimate splitting strain can be increased by 9.8%and 6.3 times,respectively,compared with ordinary cement-stabilized gravel(CSG).In terms of durability,compared with CSG,RCSG showed a 3.7%increase in the water stability property of cement-stabilized base with 1%content and 2–4 mm rubber particles,5.5%increase in the frozen coefficient,and 80.6%and 37.9%increase in the fatigue life at 0.70 and 0.85 stress ratio levels,respectively.

关键词： pavement materials cement-stabilized gravel rubber particles material components mechanical property durability performance

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Evolution of inclusions in vacuum induction melting of superalloys containing 70%return material

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Journal of Iron and Steel Research International 2024年第3期31卷 719-728页

作者： Jin-guo Gao Shu-lei Yang Shu-feng Yang Jing-she Li Wei Liu Meng-jing Zhao An-ren Wang School of Metallurgical and Ecological engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Metallurgical and Building Materials Business Department China International Engineering Consulting CorporationBeijing 100048China

The variation law of inclusions type and size in the vacuum induction melting process and ingot of Ni-based superalloy containing 70%return material was studied by industrial test sampling,and the mechanism of inclusions formation was analyzed with thermodynamic *** results show that there are mainly two types of composite inclusions in the vacuum induction melting of Ni-based superalloys,which are nitride-and oxide-based composite inclusions,like Al_(2)O_(3)-SiO_(2)-Cr_(2)O_(3),TiN-(Mo,Nb)C,*** type and proportion of inclusions from the center to the edge of the vacuum induction ingot did not change *** number density of inclusions from the center to the edge of the ingot varied less,and the size of inclusions became smaller from the center to the *** addition,thermodynamic calculations show that oxides(M_(2)O_(3))are present in the liquid phase and mainly contain Al,Ti,Cr,Fe and O *** nitride consists mainly of Ti and N and contains small amounts of Cr,C,Nb,and Mo *** is consistent with the results of industrial *** the temperature decreases,the precipitation phases such as M_(2)O_(3),MN,γ,MC,δ,γ'andμphases are gradually precipitated,where oxides and nitrides are present in the liquid *** contents of O and N elements are the main influencing factors for the inclusions content and precipitation temperature;when the nitrogen content is reduced to below 0.0015%,it can make MN precipitate below the liquid-phase line.

关键词： Ni-based superalloy Vacuum induction melting Return material Inclusion Thermodynamic

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Spatio-temporal evolution analysis of landscape pattern and habitat quality in the Qinghai Province section of the Yellow River Basin from 2000 to 2022 based on InVEST model

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Journal of Arid Land 2024年第9期16卷 1183-1196页

作者： ZHENG Guoqiang Li Cunxiu LI Runjie LUO Jing FAN Chunxia ZHU Hailing College of Geography Qinghai Normal UniversityXining 810008China Qinghai engineering consulting Center Co. Ltd.Xining 810001China Qinghai University Xining 810016China

Habitat quality is an important indicator for evaluating the quality of *** Qinghai Province section of the Yellow River Basin plays an important role in the ecological protection of the upper reaches of the Yellow River *** comprehensively analysis the alterations of habitat quality in the Qinghai Province section of the Yellow River Basin,this study utilized the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model to calculate the habitat quality index and analyze the spatio-temporal variation characteristics of habitat quality in the study area from 2000 to 2022,and calculated seven landscape pattern indices(number of patches,patch density,largest patch index(LPI),landscape shape index(LSI),contagion index(CONTAG),Shannon diversity index,and Shannon evenness index)to research the variation of landscape pattern in the study *** results showed that the number of patches,patch density,LPI,LSI,Shannon diversity index,and Shannon evenness index increased from 2000 to 2022,while the CONTAG decreased,indicating that the landscape pattern in the Qinghai Province section of the Yellow River Basin changed in the direction of distribution fragmentation,shape complexity,and *** average value of the habitat quality index in the Qinghai Province section of the Yellow River Basin from 2000 to 2022 was *** on the value of habitat quality index,we divided the level of habitat quality into five categories:lower(0.00-0.20),low(0.20-0.40),moderate(0.40-0.60),high(0.60-0.80),and higher(0.80-1.00).Most areas were at the higher habitat quality *** lower habitat quality patches were mainly distributed in Longyang Gorge and Yellow River-Huangshui River *** 2000 to 2022,the habitat quality in most areas was stable;the increase areas were mainly distributed in Guinan County,while the decrease areas were mainly distributed in Xining City,Maqen County,Xinghai County,Qumarleb County,and Darlag *** show the extent of

关键词： InVEST model landscape pattern index habitat quality largest patch index landscape shape index Shannon evenness index

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Blast waveform tailoring using controlled venting in blast simulators and shock tubes

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Defence Technology（防务技术） 2024年第7期37卷 14-26页

作者： Edward Chern Jinn Gan Alex Remennikov David Ritzel Faculty of engineering and Information Sciences University of WollongongWollongongNSW2522Australia Dyn-FX consulting Ltd 19 Laird Ave NorthAmherstburgONN9V 2T5Canada

A critical challenge of any blast simulation facility is in producing the widest possible pressure-impulse range for matching against equivalent high-explosive *** tubes and blast simulators are often constrained with the lack of effective ways to control blast wave profiles and as a result have a limited performance *** wave shaping techniques employed in some facilities are reviewed but often necessitate extensive geometric modifications,inadvertently cause flow anomalies,and/or are only applicable under very specific *** paper investigates controlled venting as an expedient way for waveforms to be tuned without requiring extensive modifications to the driver or existing geometry and could be widely applied by existing and future blast simulation and shock tube *** use of controlled venting is demonstrated experimentally using the Advanced Blast Simulator(shock tube)at the Australian National Facility of Physical Blast Simulation and via numerical flow simulations with Computational Fluid *** venting is determined as an effective method for mitigating the impact of re-reflected waves within the blast *** control method also allows for the adjustment of parameters such as tuning the peak overpressure,the positive phase duration,and modifying the magnitude of the negative phase and the secondary shock of the blast *** paper is concluded with an illustration of the potential expanded performance range of the Australian blast simulation facility when controlled venting for blast waveform tailoring as presented in this paper is applied.

关键词： Advanced blast simulator Shock wave propagation Far-field explosion Blast loads Blast waves Computational fluid dynamics

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Distributed Resource Allocation in Dispersed Computing Environment Based on UAV Track Inspection in Urban Rail Transit

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Computers, Materials & Continua 2024年第7期80卷 643-660页

作者： Tong Gan Shuo Dong Shiyou Wang Jiaxin Li Division of consulting Beijing Metro Consultancy Corporation Ltd.Beijing100037China Department of Computer and Communication engineering University of Science and Technology BeijingBeijing100083China

With the rapid development of urban rail transit,the existing track detection has some problems such as low efficiency and insufficient detection coverage,so an intelligent and automatic track detectionmethod based onUAV is urgently needed to avoid major safety *** the same time,the geographical distribution of IoT devices results in the inefficient use of the significant computing potential held by a large number of *** a result,the Dispersed Computing(DCOMP)architecture enables collaborative computing between devices in the Internet of Everything(IoE),promotes low-latency and efficient cross-wide applications,and meets users’growing needs for computing performance and service *** paper focuses on examining the resource allocation challenge within a dispersed computing environment that utilizes UAV inspection ***,the system takes into account both resource constraints and computational constraints and transforms the optimization problem into an energy minimization problem with computational *** Markov Decision Process(MDP)model is employed to capture the connection between the dispersed computing resource allocation strategy and the system ***,a method based on Double Deep Q-Network(DDQN)is introduced to derive the optimal ***,an experience replay mechanism is implemented to tackle the issue of increasing *** experimental simulations validate the efficacy of the method across various scenarios.

关键词： UAV track inspection dispersed computing resource allocation deep reinforcement learning Markov decision process

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Conditional Generative Adversarial Network Enabled Localized Stress Recovery of Periodic Composites

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Computer Modeling in engineering & Sciences 2024年第7期140卷 957-974页

作者： Chengkan Xu Xiaofei Wang Yixuan Li Guannan Wang He Zhang Transportation and Municipal engineering Institute Powerchina Huadong Engineering CorporationHangzhou310014China College of Civil engineering and Architecture Zhejiang UniversityHangzhou310058China Anhui Transport consulting&Design Institute Co. Ltd.Hefei230088China Center for Balance Architecture Zhejiang UniversityHangzhou310058China

Structural damage in heterogeneousmaterials typically originates frommicrostructures where stress concentration ***,evaluating the magnitude and location of localized stress distributions within microstructures under external loading is *** unit cells(RUCs)are commonly used to represent microstructural details and homogenize the effective response of *** work develops a machine learning-based micromechanics tool to accurately predict the stress distributions of extracted *** locally exact homogenization theory efficiently generates the microstructural stresses of RUCs with a wide range of parameters,including volume fraction,fiber/matrix property ratio,fiber shapes,and loading ***,the conditional generative adversarial network(cGAN)is employed and constructed as a surrogate model to establish the statistical correlation between these parameters and the corresponding localized *** stresses predicted by cGAN are validated against the remaining true data not used for training,showing good *** work demonstrates that the cGAN-based micromechanics tool effectively captures the local responses of composite *** can be used for predicting potential crack initiations starting from microstructures and evaluating the effective behavior of periodic composites.

关键词： Periodic composites localized stress recovery conditional generative adversarial network

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