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Numerical simulation analysis of tunnel backfill grout based on DEM-FDM coupling and particle inlet

Underground Space 2024年第1期14卷 285-299页

作者： Bin Yan rui wang Bo-song Ding Fang Dai You wang School of Civil Engineering Central South University.Changsha 410075China

Shield tunnel backfill grouting is vital to stabilize tunnel settlement at a later stage;however,most shield tunnel backfill grouting designs lack a complete theoretical reference,and numerical simulations of the grouting process are rarely *** study presents the fundamental theories of grout diffusion and pressure variation for backfill grouting during shield ***,the numerical simulation methods coupled with discrete element methods(DEM)and finite difference methods(FDM)are achieved to simulate the process of grout injection from the grouting hole into the shield tail gap and generate grout pressure on the surrounding *** diffusion state of the grout in the shield tail gap and the squeezing effect on the surrounding rock under two shield tail disengagement modes are analyzed,as well as the impact of various grouting pressure on the surface *** results indicated that the grout diffusion in the shield tail gap can be divided into three stages:the stage of diffusion with each grouting hole as the starting point,the stage of interconnection and contact of the grout injected in each grouting hole,and the final gap filling *** of the three stages can be described using the proposed *** the grouting process,the grout is injected into the shield tail gap at a certain pressure,but the grout diffuses slowly to both sides and upwards,which causes a rapid rise of the principal stresses in the soil around the *** grouting is complete,the grout pressure gradually dissipates and stabilizes,and the principal stress *** addition,backfill grouting can reduce surface settlement,but it does not affect its distribution width.

关键词： Shield tunnel Backfill grouting Discrete element Finite difference Particle generator

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Modeling of Rectangular Microchannel Heat Sink with Non-Uniform Channels and Multi-Objective Optimization

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Journal of Thermal Science 2024年第5期33卷 1701-1711页

作者： SHANG Xueshuo wang Yixin LI Qingwen wang rui CUI Zheng SHAO Wei Institute of Advanced Technology Shandong UniversityJi'nan 250014China Institute of Thermal Science and Technology Shandong UniversityJi'nan 250014China Shandong Institute of Advanced Technology Ji'nan 250100China

Rectangular microchannel heat sinks(MCHS)are widely used to cool high-heat-flux electronic ***,previous studies focused mainly on MCHS with uniform channels(UCs).This study considers a microchannel heat sink with non-uniform channels(NUCs).A mathematical model is developed based on energy equations and the Darcy flow *** expressions for total thermal resistance and coolant pressure drop are derived using the thermoelectric *** and numerical simulations are performed to verify the mathematical *** non-uniformity increases,total coolant pressure drop decreases but at the cost of higher thermal *** overall performance of NUCs is better than that of UCs because of their lower ratio of pumping power to cooling *** transfer performance of NUCs changes little for more than 120 channels and depends mainly on channel arrangement.A multi-objective optimization is conducted to minimize the thermal resistance and pumping power of an *** optimal NUC saves 64%pumping power compared with a conventional UC for the total thermal resistance of 0.1℃/W,indicating that the use of non-uniform channels could be very helpful to reduce the flow resistance of MCHS.

关键词： microchannel heat sink non-uniform channel mathematical model multi-objective optimization

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Enhancing Evolutionary Algorithms With Pattern Mining for Sparse Large-Scale Multi-Objective Optimization Problems

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IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1786-1801页

作者： Sheng Qi rui wang Tao Zhang Weixiong Huang Fan Yu Ling wang College of Systems Engineering National University of Defense TechnologyChangsha 410073China College of Systems Engineering National University of Defense TechnologyChangsha 410073and also with the Xiangjiang LaboratoryChangsha 410205China College of Transportation and Engineering Central South UniversityChangsha 410073China Department of Automation Tsinghua UniversityBeijing 100084China

Sparse large-scale multi-objective optimization problems(SLMOPs)are common in science and ***,the large-scale problem represents the high dimensionality of the decision space,requiring algorithms to traverse vast expanse with limited computational ***,in the context of sparse,most variables in Pareto optimal solutions are zero,making it difficult for algorithms to identify non-zero variables *** paper is dedicated to addressing the challenges posed by *** start,we introduce innovative objective functions customized to mine maximum and minimum candidate *** substantial enhancement dramatically improves the efficacy of frequent pattern *** this way,selecting candidate sets is no longer based on the quantity of nonzero variables they contain but on a higher proportion of nonzero variables within specific ***,we unveil a novel approach to association rule mining,which delves into the intricate relationships between non-zero *** novel methodology aids in identifying sparse distributions that can potentially expedite reductions in the objective function *** extensively tested our algorithm across eight benchmark problems and four real-world *** results demonstrate that our approach achieves competitive solutions across various challenges.

关键词： Evolutionary algorithms pattern mining sparse large-scale multi-objective problems(SLMOPs) sparse large-scale optimization.

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PbGIF1 promoting cell-proliferation in pear fruit is transcriptionally activated by Pb RR1

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Horticultural Plant Journal 2024年第3期10卷 689-697页

作者： Huibin wang Guangya Sha rui Gao Jianwen Pang rui Zhai Chengquan Yang Zhigang wang Lingfei Xu College of Horticulture Northwest A&F UniversityYanglingShaanxi 712100China College of Life Science Hebei Agricultural UniversityBaodingHebei 071000China

As a cell proliferation regulator involved in wide biological processes in plants,GRF-INTERACTING FACTOR(GIF)controls different tissues ***,whether GIF participates in fruit development remains *** to transcriptome data,we identified PbGIF1was highly expressed during fruit development in cytokinins induced parthenocarpy *** the present study,the biofunction of PbGIF1 was initially *** of PbGIF1 promoted fruit size of transgenic *** size of flesh fruit was not affected by cell expansion but the cell proliferation was promoted by overexpressing Pb *** accelerated cell proliferation process was also observed in PbGIF1-overexpressed transgenic pear fruit *** transcriptional regulation of cytokinins on PbGIF1 was further confirmed by exogenous CPPU treatments in pear *** investigate the underlying mechanism,the cytokinins-responded factor,PbRR1,was further focused *** results of Yeast-one-hybrid assay suggested that PbRR1 can bind to the promoter sequence of *** transcriptional activation of PbRR1 on PbGIF1 was also confirmed by Dual-Luciferase *** together,the results showed that cytokinins control pear fruit development via the transcriptional activation of PbGIF1 by PbRR1.

关键词： PbGIF1 Cell proliferation Pear Fruit development Cytokinins PbRR1

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A Two-Layer Encoding Learning Swarm Optimizer Based on Frequent Itemsets for Sparse Large-Scale Multi-Objective Optimization

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1342-1357页

作者： Sheng Qi rui wang Tao Zhang Xu Yang ruiqing Sun Ling wang College of Systems Engineering National University of Defense TechnologyChangsha 410073China Xiangjiang Laboratory Changsha 410205China College of Computer National University of Defense TechnologyChangsha 410073China Department of Automation Tsinghua UniversityBeijing 100084China IEEE

Traditional large-scale multi-objective optimization algorithms(LSMOEAs)encounter difficulties when dealing with sparse large-scale multi-objective optimization problems(SLM-OPs)where most decision variables are *** a result,many algorithms use a two-layer encoding approach to optimize binary variable Mask and real variable Dec ***,existing optimizers often focus on locating non-zero variable posi-tions to optimize the binary variables ***,approxi-mating the sparse distribution of real Pareto optimal solutions does not necessarily mean that the objective function is *** data mining,it is common to mine frequent itemsets appear-ing together in a dataset to reveal the correlation between *** by this,we propose a novel two-layer encoding learning swarm optimizer based on frequent itemsets(TELSO)to address these *** mined the frequent terms of multiple particles with better target values to find mask combinations that can obtain better objective values for fast ***-mental results on five real-world problems and eight benchmark sets demonstrate that TELSO outperforms existing state-of-the-art sparse large-scale multi-objective evolutionary algorithms(SLMOEAs)in terms of performance and convergence speed.

关键词： Evolutionary algorithms learning swarm optimiza-tion sparse large-scale optimization sparse large-scale multi-objec-tive problems two-layer encoding.

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Evaluating the stability and volumetric flowback rate of proppant packs in hydraulic fractures using the lattice Boltzmann-discrete element coupling method

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2052-2063页

作者： Duo wang Sanbai Li rui wang Binhui Li Zhejun Pan National Key Laboratory of Continental Shale Oil Northeast Petroleum UniversityDaqing163318China Institute of Unconventional Oil&Gas Northeast Petroleum UniversityDaqing163318China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China National Center for Applied Mathematics Shenzhen(NCAMS) Southern University of Science and TechnologyShenzhen518055China National Key Laboratory of Continental Shale Oil Daqing Oilfield of CNPCDaqing163002China Daqing Oilfield Exploration and Development Research Institute DaqingHeilongjiang163712China

The stability and mobility of proppant packs in hydraulic fractures during hydrocarbon production are numerically investigated by the lattice Boltzmann-discrete element coupling method(LB-DEM).This study starts with a preliminary proppant settling test,from which a solid volume fraction of 0.575 is calibrated for the proppant pack in the *** the established workflow to investigate proppant flowback,a displacement is applied to the fracture surfaces to compact the generated proppant pack as well as further mimicking proppant embedment under closure *** a pressure gradient is applied to drive the fluid-particle flow,a critical aperture-to-diameter ratio of 4 is observed,above which the proppant pack would *** results also show that the volumetric proppant flowback rate increases quadratically with the fracture aperture,while a linear variation between the particle flux and the pressure gradient is exhibited for a fixed fracture *** research outcome contributes towards an improved understanding of proppant flowback in hydraulic fractures,which also supports an optimised proppant size selection for hydraulic fracturing operations.

关键词： Numerical simulation Hydraulic fracturing Proppant flowback Closure stress Particulate flow

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Preparation and Reinforcement Adaptability of Jute Fiber Reinforced Magnesium Phosphate Cement Based Composite Materials

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 999-1009页

作者：刘芯州郭远臣 wang rui XIANG Kai wang Xue YE Qing College of Civil Engineering Chongqing Three Gorges UniversityChongqing 404100China

To improve the brittleness characteristics of magnesium phosphate cement-based materials(MPC)and to promote its promotion and application in the field of structural reinforcement and repair,this study aimed to increase the toughness of MPC by adding jute fiber,explore the effects of different amounts of jute fiber on the working and mechanical properties of MPC,and prepare jute fiber reinforced magnesium phosphate cement-based materials(JFRMPC)to reinforce damaged *** improvement effect of beam performance before and after reinforcement was compared,and the strengthening and toughening mechanisms of jute fiber on MPC were explored through microscopic *** experimental results show that,as the content of jute fiber(JF)increases,the fluidity and setting time of MPC decrease continuously;When the content of jute fiber is 0.8%,the compressive strength,flexural strength,and bonding strength of MPC at 28 days reach their maximum values,which are increased by 18.0%,20.5%,and 22.6%compared to those of M0,*** beam strengthened with JFRMPC can withstand greater deformation,with a deflection of 2.3 times that of the unreinforced beam at *** strain of the steel bar is greatly reduced,and the initial crack and failure loads of the reinforced beam are increased by 192.1%and 16.1%,respectively,compared to those of the unreinforced *** JF added to the MPC matrix dissipates energy through tensile fracture and debonding pull-out,slowing down stress concentration and inhibiting the free development of cracks in the matrix,enabling JFRMPC to exhibit higher strength and better *** JF does not cause the hydration of MPC to generate new compounds but reduces the amount of hydration products generated.

关键词： magnesium phosphate cement jute fiber reinforcement of damaged beam flexural behavior

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Structural evolution and high-temperature sensing performance of polymer-derived SiAlBCN ceramics

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Journal of Advanced Ceramics 2024年第4期13卷 478-485页

作者： Chao Ma Kun Liu Pengfei Shao Daoyang Han Kang wang Mengmeng Yang rui Zhao Hailong wang rui Zhang Gang Shao School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Zhongyuan Critical Metal Laboratory Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentZhengzhou UniversityZhengzhou 450002China

In situ temperature monitoring has become extremely imperative in high-temperature harsh environments and polymer-derived ceramics(PDCs)as sensing materials have attracted great ***,the stability and oxidation/corrosion resistance of PDCs cannot be simultaneously achieved at the moment,limiting their practical ***,polymer-derived SiAlBCN ceramics were synthesized via polymer conversion method under different pyrolysis *** microstructure evolution,high temperature sensing properties,and stability were investigated in *** results show that the amorphous SiAlBCN phase grows more orderly and the size of the free carbon phase enlarges with the increasing *** defect concentration displays a decreasing ***,the SiAlBCN ceramics as sensing materials exhibit a good temperature-resistance property from roo temperature to 1100℃.The fabricated SiAlBCN temperature sensor possesses excellent stability,repeatability,and ***,SiAlBCN ceramics exhibit distinguished oxidation/corrosion resistance after 100 h treatment at 1200℃in a water/oxygen environment,which is attributed to their low corrosive rate constant(0.57 mg/(cm^(2)·h))and oxidative rate constant(3.43 mg^(2)/(cm^(4)·h)).Therefore,polymer-derived SiAlBCN ceramics as sensing materials,which possess outstanding stability and oxidation/corrosion resistance,have great potential for in-situ monitoring of extreme environmental temperatures in the future.

关键词： polymer-derived SiAlBCN ceramics temperature sensor harsh environments oxidation and corrosion resistance

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Procyanidin A_1 and its digestive products alleviate acrylamide-induced IPEC-J2 cell damage through regulating Keap1/Nrf2 pathway

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Food Science and Human Wellness 2024年第3期13卷 1475-1484页

作者： Fangfang Yan Qun Lu Chengming wang rui Liu College of Food Science and Technology Huazhong Agricultural UniversityWuhan 430070China Key Laboratory of Environment Correlative Dietology(Huazhong Agricultural University) Ministry of EducationWuhan 430070China Key Laboratory of Urban Agriculture in Central China Ministry of Agriculture and Rural AffairsWuhan 430070China

Our previous study has revealed that procyanidin A_(1)(A_(1))and its simulated digestive product(D-A,)can alleviate acrylamide(ACR)-induced intestine cell ***,the underlying mechanism remains *** this study,we elucidated the molecular mechanism for and D-A_(1) to alleviate ACR-stimulated IPEC-J2 cell *** slightly activated nuclear factor erythroid 2-related factor 2(Nrf2)signaling and its target genes,but this activation could not reduce intestine cell damage.A_(1) and D-A_(1) could alleviate ACR-induced cell damage,but the effect was abrogated in cells transiently transfected with Nrf2 small interfering RNA(siRNA).Further investigation confirmed that A_(1) and D-A_(1) interacted with Ketch-like ECH-associated protein 1(Keapl),which boosted the stabilization of Nrf2,subsequently promoted the translocation of Nrf2 into the nucleus,and further increased the expression of antioxidant proteins,thereby inhibiting glutathione(GSH)consumption,maintaining redox balance and eventually alleviating ACR-induced cell ***,there was no difference between A_(1) and D-A_(1) treated groups,indicating that A_(1) can tolerate gastrointestinal digestion and may be a potential compound to limit the toxicity of ACR.

关键词： Procyanidin A_1 Digestive products Acrylamide Nuclear factor erythroid 2-related factor 2(Nrf2) Intestinal cell damage

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Towards direct superlubricity and superlow wear via amino modification of polyhydroxy alcohol solutions

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Friction 2024年第9期12卷 1980-1990页

作者： Qiang MA Chengpeng YAN rui YAN Xin XU Haifeng wang State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi'an 710072China Chongqing Innovation Center Northwestern Polytechnical UniversityChongqing 401135China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China

Friction remains as the primary mode of energy dissipation and components wear,and achieving superlubricity shows high promise in energy conservation and lifetime wear *** results in this work demonstrate that direct superlubricity combined with superlow wear can be realized for steel/Si_(3)N_(4)contacts on engineering scale when polyhydroxy alcohol solution was selectively modified by amino *** direct superlubricity occurs because 3-amino-1,2-propanediol molecules at the friction interface could be induced to rotate and adsorb vertically on the friction surface,forming in-situ thick and dense molecular films to passivate the asperity ***,amino modification is also conducive to improving the lubrication state from boundary to mixed lubrication regime by strengthening the intermolecular hydrogen bonding interaction,presenting enhanced load-bearing capability and reduced direct solid asperity ***,direct superlow average friction of 0.01 combined with superlow wear are achieved *** design principle of direct superlubricity and superlow wear in this work indeed offers an effective strategy to fundamentally improve energy efficiency and provide lifetime wear protection for moving mechanical assemblies.

关键词： direct superlubricity amino modification molecular layer superlow wear

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