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Surrounding rock pressure in the tunnel portal section through moraine under freeze-thaw action

Journal of Mountain Science 2024年第7期21卷 2480-2493页

作者： CHEN Zhimin LIU Baoli LIU Yaohui XU Jiangtao School of Civil Engineering Lanzhou Jiaotong UniversityLanzhou 730070China CSCEC AEco. co.sultants co. ltdLanzhou 730000China National and Local Joint Engineering Laboratory of Road and Bridge Engineering Disaster Prevention technology Lanzhou Jiaotong UniversityLanzhou 730070China

Moraines,characterized by the accumulation of rock and soil debris transported by glacial activity,present unique challenges for tunnel co.struction,particularly in portal sections,due to prevailing geographical and climatic co.ditions that facilitate freeze-thaw *** these challenges,there is a dearth of studies investigating the influence of freeze-thaw action and water co.tent on the mechanical properties of moraines,and no research on calculating surrounding rock pressure in moraine tunnels subjected to freeze-thaw *** this study,direct shear tests under freeze-thaw cycles were co.ducted to examine the effects of freeze-thaw cycles and water co.tent on the mechanical properties of frozen moraine.A co.prehensive parameter K,integrating the number of freeze-thaws and water co.tent,was introduced to model co.esion *** on Terzaghi Theory,we propose an improved algorithm for calculating surrounding rock pressure at the portal section of moraine *** a tunnel as a case study,surrounding rock pressure was calculated under various co.ditions to validate the Improved Algorithm's *** results show that:(1)Strength loss exhibits a linear trend with the number of freeze-thaw cycles at water co.tent levels of 4%and 8%,while at 12%water co.tent,previous freeze-thaw cycles induce more significant damage to the soil.(2)Moraine saturation peaks between 8%and 12%water *** repeated freeze-thaw cycles,moraine shear strength initially increases before decreasing with varying water co.tent.(3)The internal friction angle of moraine experiences slight reductions with prolonged freeze-thaw cycles,but both freeze-thaw cycles and water co.tent significantly influence co.esion.(4)Vertical surrounding rock pressure increases after the initial freeze-thaw cycle,particularly with higher water co.tent,although freeze-thaw cycles have minimal effect on it.(5)Freeze-thaw cycles lead to a substantial increase in lateral surrounding rock pre

关键词： Moraines Freeze-thaw cycles Direct shear test Surrounding rock pressure

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Optimization of a Pipeline-Type Savonius Hydraulic Turbine

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Fluid Dynamics & Materials Processing 2024年第5期20卷 1123-1146页

作者： Xiaohui Wang Kai Zhang Xiaobang Bai Senchun Miao Zanxiu Wu Jicheng Li School of Energy and Power Engineering Lanzhou University of TechnologyLanzhou730050China Postdoctoral Station of Civil Engineering Lanzhou University of TechnologyLanzhou730050China Postdoctoral Research Station of Xinxiang Aviation Industry(Group)co. Ltd.Xinxiang453000China Chongqing Pump Industry co. Ltd.Chongqing404100China

This study focuses on a DN50 pipeline-type Savonius hydraulic *** torque variation of the turbine in a rotation cycle is analyzed theoretically in the framework of the plane potential flow *** numerical simulations show that the change in turbine torque is co.sistent with the theoretical analysis,with the main power zone and the seco.dary power zone exhibiting a positive *** co.trast,the primary resistance zone and the seco.dary resistance zone are characterized by a negative *** relationships between the turbine’s internal flow angleθ,the deflector’s inclination angleα0,and the co.erage angleαof the power zone are introduced,and a method for calculating the optimal number of blades is proposed to maximize the power *** are presented about performance tests co.ducted on five groups of hydraulic turbines with the blade number ranging from 3 to *** results indicate that both the turbine’s reco.ery power and efficiency attain the highest values when the blade number is 4,which is in agreement with the number of blades calculated by the proposed ***,the study examines the effects of the flow rate on turbine parameters and the projected energy generation and co.t savings for a specific pipeline co.figuration.

关键词： Savonius turbine blade number numerical simulation experimental study benefit prediction

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A Numerical Study on the Effect of the Backflow Hole Position on the Performances of a Self-Priming Pump

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Fluid Dynamics & Materials Processing 2024年第5期20卷 1103-1122页

作者： Dongwei Wang Lijian Cao Weidong Wang Jiajun Hu School of Energy and Power Engineering Lanzhou University of TechnologyLanzhou730050China Sanlian Pump Industry co. Ltd.Ma’anshan243000China

A self-priming pump is a centrifugal pump that has the ability to prime itself. Typically, its performance dependson the co.figuration of its reflux hole. In this study, the ANSYS FLUENT software is used to investigate the effectsof three different radial positions of the reflux hole on gas-liquid two-phase distribution, pressure pulsation, andimp during self-priming. The research results indicate that: (1) The effective channel size for the reflux liquid toenter the volute varies depending on the location of the reflux hole. The effect of the impeller rotation on thereflux liquid beco.es more obvious as the setting distance of the reflux aperture decreases. (2) The position ofthe reflux hole significantly affects the gas phase mass fraction inside the impeller, resulting in a significant reductionin the time it takes for the mass fraction to exceed 80%. (3) The position of the reflux hole significantly affectsthe average pressure on each monitoring surface. (4) Placing the reflux hole at a excessively distant radial distancecan result in an excessive vertical co.ponent. (5) The self-priming performance of the pump can be improved tosome extent by placing the return hole at a small radial distance.

关键词： Self-priming pump self-priming time numerical calculation gas-liquid two-phase flow

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Effect of Mn co.tent on microstructure and properties of AlCrCuFeMnx high-entropy alloy

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China Foundry 2024年第2期21卷 147-158页

作者： Ning Wang Kai Ma Qiu-da Li Yu-dong Yuan Yan-chun Zhao Li Feng School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Reuse of Nonferrous Metals Lanzhou 730050China CNNC Nuclear Power Operation and Management co. Ltd.Haiyan 314300ZhejiangChina

AlCrCuFeMnx(x=0,0.5,1,1.5,and 2)high-entropy alloys were prepared using the vacuum arc melting *** microstructure and mechanical properties of AlCrCuFeMnxwere analyzed and tested by XRD,SEM,TEM,nanoindentation,and electronic universal *** results indicate that the AlCrCuFeMnxhigh-entropy alloy exhibits a dendritic structure,co.sisting of dendrites with a BCC structure,interdendrite regions with an FCC structure,and precipitates with an ordered BCC structure that form within the ***(Mn)has a strong affinity for dendritic,interdendritic,and precipitate structures,allowing it to easily enter these *** an increase in Mn co.tent,the size of the precipitated nanoparticles in the dendritic region initially increases and then ***,the area fraction initially decreases and then ***,the alloy’s strength and wear resistance decrease,while its plasticity *** Al Cr Cu Fe Mn1.5alloy boasts excellent mechanical properties,including a hardness of 360 HV and a wear rate of 2.4×10^(-5)mm^(3)·N^(-1)·mm^(-1).It also exhibits impressive yield strength,co.pressive strength,and deformation rates of 960 MPa,1,700 MPa,and 27.5%,respectively.

关键词： high-entropy alloys microstructure mechanical properties wear resistance strengthening mechanisms

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Effects of co.ling rate on microstructure and microhardness of directionally solidified Galvalume alloy

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China Foundry 2024年第3期21卷 213-220页

作者： Ji-peng Li De-gao Qiao Jian Li Xiao-yang Luo Peng Peng Xian-tao Yan Xu-dong Zhang Gansu Jiu Steel Group Hongxing Iron and Steel co. Ltd.Jiayuguan 735111GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China

The influences of co.ling rate on the phase co.stitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is co.posed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich *** addition,the primary Al dendrites show significant refinement with an increase in the withdrawal *** relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 *** is a co.bined effect of grain refinement and seco.d-phase strengthening.

关键词： Galvalume alloy directional solidification microstructure length scale microhardness

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In-situ physical/chemical cross-linked hydrogel electrolyte achieving ultra-stable zinc anode-electrolyte interface towards dendrite-free zinc ion battery

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Journal of Energy Chemistry 2024年第10期97卷 342-351,I0007页

作者： Chen-Yang Li Jiang-Lin Wang Dong-Ting Zhang Min-Peng Li Hao Chen Wei-Hai Yi Xin-Ying Ren Bao Liu Xue-Feng Lu Mao-Cheng Liu State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Lanzhou University of TechnologyLanzhou 730050GansuChina School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050GansuChina Chaowei Power Group co. LTDChangxing 313100ZhejiangChina School of Vehicle Engineering Jiangsu UniversityNanjing 210031jiangsuChina

Hydrogen evolution reaction(HER),zinc co.rosion,and dendrites growth on zinc metal anode are the major issues limiting the practical applications of zinc-ion ***,an in-situ physical/chemical cross-linked hydrogel electrolyte(carrageenan/polyacrylamide/ZnSO_(4),denoted as CPZ)has been developed to stabilize the zinc anode-electrolyte interface,which can eliminate side reactions and prevent dendrites *** in-situ CPZ hydrogel electrolyte improves the reversibility of zinc anode due to eliminating side reactions caused by active water ***,the electrostatic interaction between the SO_(4)^(-)groups in CPZ and Zn^(2+)can enco.rage the preferential deposition of zinc atoms on(002)crystal plane,which achieve dendrite-free and homogeneous zinc *** in-situ hydrogel electrolyte offers a streamlined approach to battery manufacturing by allowing for direct integration into the ***,the Zn//Zn half battery with CPZ hydrogel electrolyte can enable an ultra-long cycle over 5500 h at a current density of 0.5 mA cm^(-2),and the Zn//Cu half battery reach an average co.lombic efficiency of 99.37%.The Zn//V_(2)O_5-GO full battery with CPZ hydrogel electrolyte demonstrates94.5%of capacity retention after 2100 *** study is expected to open new thought for the development of co.mercial hydrogel electrolytes for low-co.t and long-life zinc-ion batteries.

关键词： In-suit CPZ hydrogel electrolyte Hydrogen evolution reaction and zinc co.rosion Dendrites growth Zinc anode-electrolyte interface Zn ion batteries

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Analytical solutions for full-field radiations of magnetoelectric antennas with nonlinear magnetoelastic co.pling

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Acta Mechanica Sinica 2024年第7期40卷 109-121页

作者： Baoxin Lei Zhixiong You Zhidong Zhang Yang Shi Research Center for Applied Mechanics School of Mechano-Electronic EngineeringXidian UniversityXi'an 710071China China Teleco. WanWei Information technology co. Ltd.Lanzhou 730010China

This paper presents analytical solutions for full-field radiation in magnetoelectric(ME)antennas,co.sidering a fully magnetoelastic co.pled co.stitutive relation.A nonlinear co.verse ME co.pling model is established,inco.porating mechanical,electric,and magnetic variables with generalized Maxwell *** model emphasizes the essence of ME antennas,where radiation is achieved through strain/stress-mediated co.pling between different *** magnetic flux density and electric displacement obtained from the model are used as sources to solve the full-field radiations of ME *** proposed model is validated through existing experiments and simulations,demonstrating that the radiation performance of ME antennas is strongly influenced by nonlinear magneto-elastic *** material parameters and magnetic bias significantly impact the magnetic flux density and far-field radiation due to the nonlinear magnetization *** study reveals the mechanisms behind enhanced working bandwidth and frequency tuning by examining the frequency response of the radiation impedance with material *** adjusting the initial magnetization rate,saturation magnetostriction,and saturation magnetization,the radiation efficiency/gain can be increased by 340%,108%,and 112%*** model enhances our understanding of the full-field radiation of ME antennas and provides a foundation for designing tunable ME antennas.

关键词： ME antenna Full-field radiation Magneto-elastic co.pling Radiation patterns

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Frost Resistance of Pervious co.crete Mixed with Waste Glass Powder

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Journal of Wuhan University of technology(Materials Science) 2024年第5期39卷 1325-1336页

作者： AN Baofeng LI Qiong QIAO Hongxia SU Rui WANG Xi WANG Chaoqun JIAO Daowei School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Gansu Advanced Civil Engineering Materials Engineering Research Center Lanzhou 730050China China co.struction First Group The Fifth co.struction co.Ltd Beijing 100000China

The co.tents of waste glass powder(WGP)(0%,10%,15%,20%,25%)and water-binder ratio(W/C)(0.24,0.26,0.28)were used as influencing factors,and the quality loss rate(Δm)and co.pressive strength loss rate(Δfc)were used as characterization *** Ca/Si ratio and main element co.tents of C-S-H gels with different WGP co.tent were investigated by energy dispersive spectrometry(EDS).The pore structure evolution characteristics of WGP co.posite cementing materials were investigated by low field nuclear magnetic resonance(NMR).UsingΔfc as the index of frost resistance degradation and Weibull function,the frost resistance degradation of glass doped pervious co.crete(WGP-PC)was *** results show that,with WGP,for the same number of cycles,Δm andΔfc decrease and increase with the increase of *** the same WGP co.tent,Δm andΔfc decrease first and then increase with the increase of W/*** 100 freeze-thaw cycles,the samples with WGP co.tent of 20%and W/C of 0.26 have the best *** tests show that with the increase of WGP co.tent,the Ca/Si ratio of C-S-H gel decreases at first and then increases with the increase of WGP *** extreme value of Ca/Si is 2.36 when WGP is added by 20%.The pore volume of hardened paste with 20%WGP co.tent decreased by 18.6%co.pared with that of cement system without *** overall co.pactness of the specimen was *** the basis of the test data,a life prediction model was established acco.ding to Weibull *** experiment showed thatΔfc co.ld be used as a durability degradation index,and the slope of the reliability curve became gentle after WGP was added,which reduced the damage degradation rate of PC.W/C was ***'s about 5000 hours.

关键词： pervious co.crete glass powder frost resistance energy dispersive analysis test low field nuclear magnetic resonance instrument life prediction

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The co.figuration of Au^(δ+)-ZrO_(2)^(δ−)species induced activation enhances electrocatalytic co.(2)to formate co.version

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Nano Research 2024年第7期17卷 6006-6015页

作者： Yongjian Jia Yadi Zhang Mengque Lin Yangyang Cheng Yanjie Xu National Engineering Research Center for technology and Equipment of Environmental Deposition Lanzhou Jiaotong UniversityLanzhou 730070China Key Lab of Opt-Electronic technology and Intelligent co.trol of Ministry of Education Lanzhou Jiaotong UniversityLanzhou 730070China School of Environmental Engineering and Chemistry Luoyang Institute of Science and TechnologyLuoyang 471023China

Electrochemical co.(2)co.version into value-added chemicals is a promising technology to solve the greenhouse effect and recycle chemical ***,the electrochemical co.(2)reduction reaction(e-co.(2)RR)is seriously co.promised by weak co.(2)adsorption and a rough co.(2)activation process based on the chemical inertness of the co.(2)molecule and the formed fragile metal–C/O *** this paper,we designed and fabricated Au particles embedded in ZrO_(2).The co.figuration of Au particles being of positive charge and ZrO_(2)with negative charge is induced and generated by metal–support interactions(MSIs).As a result,Au/ZrO_(2)@C presents a big difference in the co.(2)co.version co.pared with the known work,affording a formate yield of 112.5μmol·cm^(−2)·h^(−1)at−1.1 V *** hydrogen electrode(RHE),and a max formate Faradaic efficiency of up to 94.1%at−0.9 V *** superior performance was attributed to the activated Au–ZrO_(2)interface to form the Au^(δ+)*** insitu Fourier transform infrared(FTIR)spectrosco.y and theoretical calculations show that the MSIs co.figuration can be inclined to the*Oco.intermediate generation on Au^(δ+)species activating co.(2)molecules and then accelerate the formation of the*OCHO intermediate in e-co.(2)RR,thereby favoring the co.(2)co.version to formate.

关键词： electrochemical co.(2)reduction reaction(e-co.(2)RR) Au_(δ+)species formic acid *OCHO intermediate metal-support interactions

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Electricity Carbon Quota Trading Scheme based on Certificateless Signature and Blockchain

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co.puter Modeling in Engineering & Sciences 2024年第2期138卷 1695-1712页

作者： Xiaodong Yang Runze Diao Tao Liu Haoqi Wen Caifen Wang co.lege of co.puter Science and Engineering Northwest Normal UniversityLanzhou730070China Institute of China Teleco.Wanwei China TelecomWanwei Information Technology Co.Ltd.Lanzhou730030China co.lege of Big Data and Internet Shenzhen Technology UniversityShenzhen518118China Key Laboratory of Cryptography and Data Analytics Northwest Normal UniversityLanzhou730070China

The carbon tradingmarket can promote“carbon peaking”and“carbon neutrality”at low co.t,but carbon emission quotas face attacks such as data forgery,tampering,co.nterfeiting,and replay in the electricity trading *** signatures are a new cryptographic technology that can address traditional cryptography’s general essential certificate requirements and avoid the problem of crucial escrowbased on identity ***,most certificateless signatures still suffer fromvarious security *** present a secure and efficient certificateless signing scheme by examining the security of existing certificateless signature *** ensure the integrity and verifiability of electricity carbon quota trading,we propose an electricity carbon quota trading scheme based on a certificateless signature and *** scheme utilizes certificateless signatures to ensure the validity and nonrepudiation of transactions and adopts blockchain technology to achieve immutability and traceability in electricity carbon quota *** addition,validating electricity carbon quota transactions does not require time-co.suming bilinear pairing *** results of the analysis indicate that our scheme meets existential unforgeability under adaptive selective message attacks,offers co.ditional identity privacy protection,resists replay attacks,and demonstrates high co.puting and co.munication performance.

关键词： Electricity carbon trading certificateless signature blockchain forgery attack carbon quota

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