A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stre...A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stress−strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress.Furthermore,the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil,reducing the lateral displacement of the superstructure.Cement-soil reinforcement reduced shear strains,inhibited sand liquefaction,and reduced superstructure displacements by 27%−47%(instantaneous)and 40%−65%(permanent).The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered,along with the change pattern of the subgrade reaction after sand liquefaction.An equivalent subgrade reaction calculation method is proposed,which accounts for the horizontal load-sharing ratios of soils with two different strengths.The test results indicate that the pile stress and displacement,estimated using the equivalent subgrade reaction,are in good agreement with the observed results.展开更多
Correction to:Nuclear Science and Techniques(2025)36:111 https://doi.org/10.1007/s41365-025-01681-9.In the sentence beginning‘The weights of the parameters used for the…’in this article,the text‘RCSs’should have ...Correction to:Nuclear Science and Techniques(2025)36:111 https://doi.org/10.1007/s41365-025-01681-9.In the sentence beginning‘The weights of the parameters used for the…’in this article,the text‘RCSs’should have read‘SCRs’.In Table 7 of this article,the column header ρ_fuel was incorrect and should have read CPv_fuel.For completeness and transparency,the old incorrect version and the corrected version of Table 7 are displayed below.展开更多
Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properti...Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properties.The integration of FG materials with auxetic structures enhances their adaptability in advanced engineering applications.However,understanding their dynamic behavior under external excitations is essential for optimal design and structural reliability.Nonlinear interactions in such structures pose significant challenges in vibration analysis,necessitating robust analytical methods.This study presents a closed-form solution for the nonlinear forced vibration analysis of sandwich FG auxetic beams,offering an accurate and efficient method for predicting their dynamic response.The beam consists of two FG face sheets with material properties varying through the thickness and a re-entrant honeycomb auxetic core with an adjustable Poisson's ratio.The governing nonlinear equations of motion are derived using the first-order shear deformation theory(FSDT),the modified Gibson model,and the von Kármán relations,formulated through Hamilton's principle.A closed-form solution is obtained via the Galerkin method and multiple-scale technique.The results demonstrate that FG layers enable control of the overweight and dynamic response amplitude,with positive power law indexes reducing weight.Comparisons with finite element results confirm the accuracy of the proposed formulation.展开更多
Forced imbibition,the invasion of a wetting fluid into porous rocks,plays an important role in the effective exploitation of hydrocarbon resources and the geological sequestration of carbon dioxide.However,the interfa...Forced imbibition,the invasion of a wetting fluid into porous rocks,plays an important role in the effective exploitation of hydrocarbon resources and the geological sequestration of carbon dioxide.However,the interface dynamics influenced by complex topology commonly leads to non-wetting fluid trapping.Particularly,the underlying mechanisms under viscously unfavorable conditions remain unclear.This study employs a direct numerical simulation method to simulate forced imbibition through the reconstructed digital rocks of sandstone.The interface dynamics and fluid–fluid interactions are investigated through transient simulations,while the pore topology metrics are introduced to analyze the impact on steady-state residual fluid distribution obtained by a pseudo-transient scheme.The results show that the cooperative pore-filling process promoted by corner flow is dominant at low capillary numbers.This leads to unstable inlet pressure,mass flow,and interface curvature,which correspond to complicated interface dynamics and higher residual fluid saturation.During forced imbibition,the interface curvature gradually increases,with the pore-filling mechanisms involving the cooperation of main terminal meniscus movement and arc menisci filling.Complex topology with small diameter pores may result in the destabilization of interface curvature.The residual fluid saturation is negatively correlated with porosity and pore throat size,and positively correlated with tortuosity and aspect ratio.A large mean coordination number characterizing global connectivity promotes imbibition.However,high connectivity characterized by the standardized Euler number corresponding to small pores is associated with a high probability of non-wetting fluid trapping.展开更多
The phase-field method is used to study the free dendritic crystal growth under forced convection with hypergravity,the hypergravity term is introduced into the liquid-phase momentum equation to examine the dendritic ...The phase-field method is used to study the free dendritic crystal growth under forced convection with hypergravity,the hypergravity term is introduced into the liquid-phase momentum equation to examine the dendritic growth.The paper focuses on the morphology of dendrite growth as well as the tip radius of the upstream dendritic arm and the average growth velocity of dendrite tips under different hypergravity levels.The results show that the morphology of dendrite changes significantly under represent simulation conditions when the hypergravity reaches 35_(g0),the upstream dendritic arm will bifurcate and the horizontal dendrite arms gradually tilt upwards.This change is mainly caused by the hypergravity and flow changing the temperature field near the dendrite interface.In addition,before the morphology of the dendrite is significantly altered,the radius of the tip of the dendrite upstream arm becomes larger with the increase in hypergravity,and the average growth velocity will increase linearly with it.The morphology of dendritic growth under different hypergravity and the changes in the tip radius along with the average growth velocity of the upstream dendritic tip with hypergravity are given in this paper.Finally,the reasons for these phenomena are analyzed.展开更多
The unsteady magnetohydrodynamical(MHD)free convection flow of an incompressible,electrically conducting hybrid nanofluid within a vertical cylindrical geometry is investigated,incorporating the effects of thermal rad...The unsteady magnetohydrodynamical(MHD)free convection flow of an incompressible,electrically conducting hybrid nanofluid within a vertical cylindrical geometry is investigated,incorporating the effects of thermal radiation,viscous dissipation,and internal heat generation.The system is subjected to a time-periodic boundary temperature condition.The Laplace and finite Hankel transforms are used to derive the exact solutions for the velocity and temperature distributions.The effects of various key physical parameters,including the Richardson number,the Eckert number,the radiation parameter,the heat source parameter,and the nanoparticle volume fraction,are considered.The numerical results reveal that increasing the volume fraction significantly enhances the thermal conductivity and temperature,while the magnetic field intensity and viscous dissipation strongly influence the fluid motion and heat transport.Additionally,the pulsating boundary conditions produce distinct oscillatory behaviors in both the velocity and temperature fields.These findings provide important insights into optimizing the heat transfer performance in cylindrical systems such as electronic cooling modules and energy storage devices operating under dynamic thermal conditions.展开更多
Flutter and forced response, as two main branches of aeroelasticity, can lead to high-cycle fatigue failure of turbomachinery blades. Efficiently and accurately assessing aeroelastic performance of turbomachinery blad...Flutter and forced response, as two main branches of aeroelasticity, can lead to high-cycle fatigue failure of turbomachinery blades. Efficiently and accurately assessing aeroelastic performance of turbomachinery blades is essential in the routine design. In this work, the Time Collocation Method (TCM) which uses the cubic B-spline to approximate flow variables is first thoroughly studied and then combined with the moving grid technique to analyze aeroelastic flow fields. To showcase its advantage over the Harmonic Balance (HB) method which uses a truncated Fourier series to approximately represent flow variables, a matrix analysis of the one-dimensional advection equation is first performed. The results of stability analysis are verified by two test cases: the Durham linear oscillating turbine cascade and a two-blade-row transonic compressor. The vibration of the blade of the first case is driven by a motor while the excitation force of the second case comes from blade row interaction. The results show that the time collocation method has a faster convergence rate and is more stable than the harmonic balance method, especially for cases with a large maximum grid reduced frequency. More importantly, the time collocation method is capable of accurately predicting aeroelastic performance of turbomachinery blades.展开更多
Solidification structure of casting strands significantly impacts the subsequent processing and service properties of the steel products,which correlates closely with the melt flow during the solidification process.Se...Solidification structure of casting strands significantly impacts the subsequent processing and service properties of the steel products,which correlates closely with the melt flow during the solidification process.Several abnormal solidification phenomena and segregation characteristics observed in slab casting are elucidated by referencing to their related flow patterns of molten steel calculated by a multi-field coupling model for actual casting conditions.Eventually,the effect of forced convection on the solidification structure was discussed.The results show that the forced convection generated by electromagnetic stirring and/or nozzle jet will remove the solute-enriched molten steel between the dendrite in front of the solidifying shell,and change solute distribution at the interface of dendrite tips,leading to the white bands and dendrite deflection.In the white band region,a dense dendrite structure without dendrite segregation appears.Moreover,forced convection results in a higher growth rate on the upstream side than the backflow side of the dendrite tip,promoting the columnar crystal deflection.In addition,dendrite fragmentation upon the forced convection during solidification will increase the equiaxed crystal ratio of the as-cast slab and the number of the spot-like semi-macrosegregation.The carbon extreme range decreased with the change in electromagnetic stirring process,indicating a significant improvement in the composition uniformity of the slab casting.It is suggested that the final quality of rolled products could be improved from the very beginning of casting and solidification through regulating the as-cast solidification structure.展开更多
The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concr...The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concrete(SFRC)is constructed by discrete element method.The model encompasses the concrete matrix,aggregate,interfacial transition zone and steel fibers,taking into account the random shape of the coarse aggregate and the stochastic distribution of steel fibers.It captures microscopic-level interactions among the coarse aggregate,steel fibers,and matrix.Subsequently,a comprehensive procedure is formulated to calibrate the microscopic parameters required by the model,and the reliability of the model is verified by comparing with the experimental results.Furthermore,a coupled finite difference method-discrete element method approach is used to construct the model of the split Hopkinson pressure bar.Compression tests are simulated on SFRC specimens with varying steel fiber contents under static and dynamic loading conditions.Finally,based on the advantages of DEM analysis at the mesoscopic level,this study analyzed mechanisms of enhancement and crack arrest in SFRC.It shed a light on the perspectives of interface failure process,microcrack propagation,contact force field evolution and energy analysis,offering valuable insights for related mining engineering applications.展开更多
Disk-drum structures jointed by bolted flanges(DDSJBFs)are core parts in aircraft engines,whose dynamic responses affect structural overall safety and service performance.However,studies on the dynamic response of DDS...Disk-drum structures jointed by bolted flanges(DDSJBFs)are core parts in aircraft engines,whose dynamic responses affect structural overall safety and service performance.However,studies on the dynamic response of DDSJBFs under base excitation are not found in available literature.In the present work,the dynamic responses for DDSJBFs subjected to base excitation are investigated both theoretically and experimentally.The kinetic energy and potential energy of disk,drum,and flange are derived according to the Kirchhoff plate,the Sanders’shell,and the Euler-Bernoulli beam theories,respectively,where the influences of flange and the mass of bolt are taken into account.The artificial spring method is applied to model the bolted joint.The Chebyshev orthogonal polynomials are adopted as the admissible functions of disk and drum,and the Lagrange equations are used to obtain the motion equation.The motion equation is solved by using the Newmark-beta approach and the dynamic responses under base excitation are acquired.A series of experiment studies are conducted on a DDSJBF to demonstrate the correctness of established theoretical model.Finally,study results show that because the relative motion between bolted flange joint interfaces generates friction damping,increasing the excitation amplitude causes the increase of damping ratio of DDSJBFs on the whole,and the increase of resonant peak value exhibits a slowing trend.The above phenomenon becomes more evident when the number of bolt is less.With the increase of bolt mass and flange size,the resonant frequency significantly decreases,while the resonant peak value remains unchanged.展开更多
Revealing the combined influence of interfacial damage and nonlinear factors on the forced vibration is significant for the stability design of fluid-conveying pipes, which are usually assembled in aircraft. The nonli...Revealing the combined influence of interfacial damage and nonlinear factors on the forced vibration is significant for the stability design of fluid-conveying pipes, which are usually assembled in aircraft. The nonlinear forced resonance of fluid-conveying layered pipes with a weak interface and a movable boundary under the external excitation is studied. The pipe is simply supported at both ends, with one end subject to a viscoelastic boundary constraint described by KelvinVoigt model. The weak interface in the pipe is considered in the refined displacement field of the layered pipe employing the interfacial cohesive law. The governing equations are derived by Hamilton's variational principle. Geometric nonlinearities including nonlinear curvature, longitudinal inertia nonlinearity and nonlinear constraint force are comprehensively considered during the theoretical derivation. Amplitude-frequency bifurcation diagrams are obtained utilizing a perturbation-Incremental Harmonic Balance Method(IHBM). Results show that interfacial damage and viscoelastic constraints from boundary and foundation have an important influence on the linear and nonlinear dynamic behavior of the system.展开更多
This research focuses on developing innovative hybrid solar dryers that combine solar Photovoltaic(PV)and solar thermal systems for sustainable food preservation in Pakistan,addressing the country’s pressing issues o...This research focuses on developing innovative hybrid solar dryers that combine solar Photovoltaic(PV)and solar thermal systems for sustainable food preservation in Pakistan,addressing the country’s pressing issues of high post-harvest losses and unreliable energy sources.The proposed active hybrid solar dryer features a drying cabinet,two Direct Current(DC)fans for forced convection,and a resistive heating element powered by a 180 W solar PV panel.An energy-storing battery ensures continuous supply to the auxiliaries during periods of low solar irradiance,poor weather conditions,or nighttime.Tomatoes,a delicate and in-demand crop,were selected for experimentation due to their high perishability.Three experiments were conducted on the same prototype:natural convection direct solar dryer(NCDSD),forced convection direct solar dryer(FCDSD),and forced convection hybrid solar dryer(FCHSD).Each experiment began with 0.2 kg of tomatoes at 94%moisture content,achieving significant reductions:28.57%with NCDSD,16.667%with FCDSD,and 16.667%with FCHSD.The observed drying rates varied:1.161 kg/h for NCDSD,2.062 kg/h for FCDSD,and 2.8642 kg/h for FCHSD.This study presents a comparative analysis of efficiency,drying rate,and cost-effectiveness,alongside the system’s economic and environmental feasibility.展开更多
The damped Helmholtz-Duffing oscillator is a topic of great interest in many different fields of study due to its complex dynamics.By transitioning from conventional continuous differential equations to their fractal ...The damped Helmholtz-Duffing oscillator is a topic of great interest in many different fields of study due to its complex dynamics.By transitioning from conventional continuous differential equations to their fractal counterparts,one gains insights into the system's response under new mathematical frameworks.This paper presents a novel method for converting standard continuous differential equations into their fractal equivalents.This conversion occurs after the nonlinear system is transformed into its linear equivalent.Numerical analyses show that there are several resonance sites in the fractal system,which differ from the one resonance point found in the continuous system.One important finding is that the fractal system loses some of its stabilizing power when decaying behavior is transformed into a diffuse pattern.Interestingly,a decrease in the fractal order in resonance settings shows a stabilizing impact,highlighting the dynamics'complexity inside fractal systems.This endeavor to convert to fractals is a revolutionary technique that is being employed for the first time.展开更多
The high-quality assembly of Large Aircraft Components(LACs)is essential in modern aviation manufacturing.Numerical control locators are employed for the posture adjustment of LAC,yet the system's multi-input mult...The high-quality assembly of Large Aircraft Components(LACs)is essential in modern aviation manufacturing.Numerical control locators are employed for the posture adjustment of LAC,yet the system's multi-input multi-output,nonlinearity,and strong coupling presents significant challenges.The substantial internal force generated during the adjustment process can potentially damage the LAC and degrade the assembly quality.Hence,a workspace-based hybrid force position control scheme was developed to achieve high quality assembly with high-precision and lower internal force.Firstly,an offline workspace analysis with inherent geometric characteristics to form time-varying posture error constraint.Then,the posture error is integrated into the online position axis control to ensure tracking the ideal posture,while the force control axis compensates for posture deviation by minimizing internal force,thereby achieving high precision and low internal force.Finally,the effectiveness was demonstrated through experiments.The root mean square errors of orientation and position are 104 rad and 0.1 mm,respectively.A reduction in internal force can range from 10.96%to 57.4%compared to the traditional method.Key points'max position error is decreased from 0.32 mm to 0.18 mm,satisfying the 0.5 mm tolerance.Therefore,the proposed method will help promote the development of high-performance manufacturing.展开更多
This study examines radon emissions as potential proxies for environmental change in tropical Andean ecosystems undergoing rapid glacier retreat due to climate forcing.The research was conducted in the proglacial zone...This study examines radon emissions as potential proxies for environmental change in tropical Andean ecosystems undergoing rapid glacier retreat due to climate forcing.The research was conducted in the proglacial zone of the Yana Ucsha glacier in the Peruvian Andes,where field campaigns between July and November 2023 yielded radon measurements at approximately 28-day intervals across ten monitoring sites(M1-M10).Radon flux was measured using LR115 detectors and complemented by analyses of soil texture and the topographic wetness index(TWI)to assess the influence of environmental variables.Results demonstrate that radon emissions are strongly modulated by soil moisture,which in turn is regulated by regional air temperature and glacier runoff.A significant inverse relationship was identified between radon exhalation and regional air temperature,indicating that warmer periods suppress radon release due to increased soil moisture from enhanced glacier melt.Conversely,the coldest monitoring interval(second period)exhibited markedly higher radon exhalation,reaching up to 0.45 and 0.32 Bq m^(-2)hm^(-1)at sites M1 and M4,respectively-approximately four to five times greater than the baseline range(0-0.10 Bq m^(-2)hm^(-1))observed during other periods.This pronounced temporal anomaly coincided with lower regional air temperatures,reduced glacier runoff,and drier soil conditions,highlighting strong climatic control on radon emissions.These findings suggest that ongoing glacier retreat and climate change may constrain or reduce radon emission rates in Andean proglacial environments,with important implications for environmental monitoring and ecosystem dynamics.Overall,this study provides novel insights into the interactions among cryospheric,atmospheric,and radon dynamics in the tropical Andes.展开更多
Considering the Hamaker constant,inclusion size,and distance between inclusions on the surface of the molten steel,a new collision model of the inclusions on the surface of the molten steel was established based on in...Considering the Hamaker constant,inclusion size,and distance between inclusions on the surface of the molten steel,a new collision model of the inclusions on the surface of the molten steel was established based on in-situ observed results of the collision process of different types of inclusions on the surface of the molten steel.The developed model can be used to calculate the attraction of inclusions on the surface of the molten steel including Al_(2)O_(3)MgO,SiO_(2),etc.展开更多
Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pell...Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.展开更多
Systematic understanding of the interaction between cells and their microenvironment is of wide interest.To investigate this interaction,a flexible micropillar array device integrating dual functions of cell behavior ...Systematic understanding of the interaction between cells and their microenvironment is of wide interest.To investigate this interaction,a flexible micropillar array device integrating dual functions of cell behavior regulation and adhesion measurement is developed.Micropillar arrays with high and low densities are designed to explore the role of substrate topography in the behavior of human bone marrow mesenchymal stem cells.In addition,a method is established for quantifying weak cell adhesion forces on the basis of micropillar deflections.The results show that cell cytoplasmic adhesion is greater on a low-density micropillar array than that on a high-density array and is localized mainly in the perinuclear region of the cytoplasm rather than in pseudopods.It is also found that the micropillar array topography facilitates the oriented spreading of cell morphology and pseudopod formation,and a reduction in focal adhesion aggregation and F-actin polarization compared with a flat substrate.Notably,cells cultured on a low-density micropillar array exhibited a higher number of pseudopods,stronger adhesion forces,and greater stiffness compared with those on a high-density array.In summary,this work employs an adhesion force sensor,immunofluorescence staining,and atomic force microscopy to investigate the mechanical properties of cells and elucidate the mechanisms by which micropillar topographical cues regulate the adhesion of mesenchymal stem cells to the substrate.The micropillar array force sensor developed in this study provides an effective tool for simultaneously modulating cell behavior and quantifying adhesion forces,offering valuable insights for biomechanical research.展开更多
The rapid development of new-quality productive forces(NQPF)has intensified the demand for high-level innovative talent.As a representative of NQPF,generative artificial intelligence(GenAI)offers powerful tools to res...The rapid development of new-quality productive forces(NQPF)has intensified the demand for high-level innovative talent.As a representative of NQPF,generative artificial intelligence(GenAI)offers powerful tools to reshape talent cultivation but also presents significant challenges,including skill hollowing,ethical risks,and a growing disconnect between education and industry needs.Currently,graduate-level software engineering education struggles with outdated curricula and insufficient alignment with practical demands.In this paper,we propose a dual-core collaborative framework driven by“GenAI technology”and“industry demand”.Under this framework,we design a four-dimensional capability development path to enhance graduate students’innovation in software engineering practice.This path focuses on①scientific research innovation,②engineering problem-solving,③cross-domain collaborative evolution,and④ethical risk governance.The proposed approach promotes a shift from traditional knowledge transfer to human-machine collaborative innovation,aligning talent cultivation with the demands of the NQPF.展开更多
Against the backdrop of profound restructuring in the global industrial and supply chains,data elements have emerged as a critical force driving the transformation of enterprises'new quality productive forces.To a...Against the backdrop of profound restructuring in the global industrial and supply chains,data elements have emerged as a critical force driving the transformation of enterprises'new quality productive forces.To address the ambiguity surrounding its micro-level empowerment mechanism,this paper empirically examines the impact of data elements on enterprises'new quality productive forces and its transmission channels using panel data of Chinese A-share listed firms from 2014 to 2023.The results show that data elements significantly improve the level of enterprises'new quality productive forces.Heterogeneity analysis indicates that this promotional effect is more pronounced in non-state-owned enterprises,large-scale enterprises,and low-leverage enterprises.Mechanism tests confirm that data elements empower new quality productive forces through three paths:enhancing enterprise innovation capability,improving internal operational efficiency,and promoting inter-firm collaboration efficiency.This study provides empirical evidence for understanding the micro-level empowerment logic of data elements and offers theoretical references and practical implications for advancing the deep integration of the digital economy and the real economy.展开更多
基金Project(52078129)supported by the National Natural Science Foundation of ChinaProject(MTF2023009)supported by the Open Project of Key Laboratory of Transport Industry of Comprehensive Transportation Theory(Nanjing Modern Multimodal Transportation Laboratory),ChinaProject(2242024K40037)supported by the Fundamental Research Funds for the Central Universities,China。
文摘A shaking table test was performed to investigate the different responses of piles with and without cement-soil reinforcement,considering both inertial and kinematic interactions.A comparison of the dynamic shear stress−strain hysteresis curves of soil profiles on the pile side with and without cement-soil reinforced piles indicates that cement-soil reinforced piles not only bear more tremendous shear stress but also have smaller strains under the action of cyclic shear stress.Furthermore,the cement-soil on the pile side not only shares part of the shear stress and modifies the bending moment distribution but also significantly enhances the resistance of the pile-side soil,reducing the lateral displacement of the superstructure.Cement-soil reinforcement reduced shear strains,inhibited sand liquefaction,and reduced superstructure displacements by 27%−47%(instantaneous)and 40%−65%(permanent).The proportion of horizontal load sharing between cement-soil reinforcement and saturated sand is considered,along with the change pattern of the subgrade reaction after sand liquefaction.An equivalent subgrade reaction calculation method is proposed,which accounts for the horizontal load-sharing ratios of soils with two different strengths.The test results indicate that the pile stress and displacement,estimated using the equivalent subgrade reaction,are in good agreement with the observed results.
文摘Correction to:Nuclear Science and Techniques(2025)36:111 https://doi.org/10.1007/s41365-025-01681-9.In the sentence beginning‘The weights of the parameters used for the…’in this article,the text‘RCSs’should have read‘SCRs’.In Table 7 of this article,the column header ρ_fuel was incorrect and should have read CPv_fuel.For completeness and transparency,the old incorrect version and the corrected version of Table 7 are displayed below.
文摘Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properties.The integration of FG materials with auxetic structures enhances their adaptability in advanced engineering applications.However,understanding their dynamic behavior under external excitations is essential for optimal design and structural reliability.Nonlinear interactions in such structures pose significant challenges in vibration analysis,necessitating robust analytical methods.This study presents a closed-form solution for the nonlinear forced vibration analysis of sandwich FG auxetic beams,offering an accurate and efficient method for predicting their dynamic response.The beam consists of two FG face sheets with material properties varying through the thickness and a re-entrant honeycomb auxetic core with an adjustable Poisson's ratio.The governing nonlinear equations of motion are derived using the first-order shear deformation theory(FSDT),the modified Gibson model,and the von Kármán relations,formulated through Hamilton's principle.A closed-form solution is obtained via the Galerkin method and multiple-scale technique.The results demonstrate that FG layers enable control of the overweight and dynamic response amplitude,with positive power law indexes reducing weight.Comparisons with finite element results confirm the accuracy of the proposed formulation.
基金supported by the National Natural Science Foundation of China(Grant Nos.42172159 and 42302143)the Postdoctora Fellowship Program of the China Postdoctoral Science Foundation(CPSF)(Grant No.GZB20230864).
文摘Forced imbibition,the invasion of a wetting fluid into porous rocks,plays an important role in the effective exploitation of hydrocarbon resources and the geological sequestration of carbon dioxide.However,the interface dynamics influenced by complex topology commonly leads to non-wetting fluid trapping.Particularly,the underlying mechanisms under viscously unfavorable conditions remain unclear.This study employs a direct numerical simulation method to simulate forced imbibition through the reconstructed digital rocks of sandstone.The interface dynamics and fluid–fluid interactions are investigated through transient simulations,while the pore topology metrics are introduced to analyze the impact on steady-state residual fluid distribution obtained by a pseudo-transient scheme.The results show that the cooperative pore-filling process promoted by corner flow is dominant at low capillary numbers.This leads to unstable inlet pressure,mass flow,and interface curvature,which correspond to complicated interface dynamics and higher residual fluid saturation.During forced imbibition,the interface curvature gradually increases,with the pore-filling mechanisms involving the cooperation of main terminal meniscus movement and arc menisci filling.Complex topology with small diameter pores may result in the destabilization of interface curvature.The residual fluid saturation is negatively correlated with porosity and pore throat size,and positively correlated with tortuosity and aspect ratio.A large mean coordination number characterizing global connectivity promotes imbibition.However,high connectivity characterized by the standardized Euler number corresponding to small pores is associated with a high probability of non-wetting fluid trapping.
基金supported by the National Natural Science Foundation of China(Grant No.52588202)。
文摘The phase-field method is used to study the free dendritic crystal growth under forced convection with hypergravity,the hypergravity term is introduced into the liquid-phase momentum equation to examine the dendritic growth.The paper focuses on the morphology of dendrite growth as well as the tip radius of the upstream dendritic arm and the average growth velocity of dendrite tips under different hypergravity levels.The results show that the morphology of dendrite changes significantly under represent simulation conditions when the hypergravity reaches 35_(g0),the upstream dendritic arm will bifurcate and the horizontal dendrite arms gradually tilt upwards.This change is mainly caused by the hypergravity and flow changing the temperature field near the dendrite interface.In addition,before the morphology of the dendrite is significantly altered,the radius of the tip of the dendrite upstream arm becomes larger with the increase in hypergravity,and the average growth velocity will increase linearly with it.The morphology of dendritic growth under different hypergravity and the changes in the tip radius along with the average growth velocity of the upstream dendritic tip with hypergravity are given in this paper.Finally,the reasons for these phenomena are analyzed.
基金Project supported by the National Natural Science Foundation of China(No.12250410244)the Jiangsu Funding Program for Excellent Postdoctoral Talent of China(No.2023ZB884)+2 种基金the Foreign Expert Project funding of China(No.WGXZ2023017L)the Shuang-Chuang(SC)Doctor Program of Jiangsu Provincethe Longshan Scholar Program of Nanjing University of Information Science&Technology。
文摘The unsteady magnetohydrodynamical(MHD)free convection flow of an incompressible,electrically conducting hybrid nanofluid within a vertical cylindrical geometry is investigated,incorporating the effects of thermal radiation,viscous dissipation,and internal heat generation.The system is subjected to a time-periodic boundary temperature condition.The Laplace and finite Hankel transforms are used to derive the exact solutions for the velocity and temperature distributions.The effects of various key physical parameters,including the Richardson number,the Eckert number,the radiation parameter,the heat source parameter,and the nanoparticle volume fraction,are considered.The numerical results reveal that increasing the volume fraction significantly enhances the thermal conductivity and temperature,while the magnetic field intensity and viscous dissipation strongly influence the fluid motion and heat transport.Additionally,the pulsating boundary conditions produce distinct oscillatory behaviors in both the velocity and temperature fields.These findings provide important insights into optimizing the heat transfer performance in cylindrical systems such as electronic cooling modules and energy storage devices operating under dynamic thermal conditions.
基金supported by the Science Center for Gas Turbine Project,China(No.P2022-C-II-001-001)the National Science and Technology Major Project,Chinathe Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(No.CX2022045).
文摘Flutter and forced response, as two main branches of aeroelasticity, can lead to high-cycle fatigue failure of turbomachinery blades. Efficiently and accurately assessing aeroelastic performance of turbomachinery blades is essential in the routine design. In this work, the Time Collocation Method (TCM) which uses the cubic B-spline to approximate flow variables is first thoroughly studied and then combined with the moving grid technique to analyze aeroelastic flow fields. To showcase its advantage over the Harmonic Balance (HB) method which uses a truncated Fourier series to approximately represent flow variables, a matrix analysis of the one-dimensional advection equation is first performed. The results of stability analysis are verified by two test cases: the Durham linear oscillating turbine cascade and a two-blade-row transonic compressor. The vibration of the blade of the first case is driven by a motor while the excitation force of the second case comes from blade row interaction. The results show that the time collocation method has a faster convergence rate and is more stable than the harmonic balance method, especially for cases with a large maximum grid reduced frequency. More importantly, the time collocation method is capable of accurately predicting aeroelastic performance of turbomachinery blades.
基金The authors are grateful to Weifang Science and Technology Development Plan Project(2023ZJ1166)for supporting this work.
文摘Solidification structure of casting strands significantly impacts the subsequent processing and service properties of the steel products,which correlates closely with the melt flow during the solidification process.Several abnormal solidification phenomena and segregation characteristics observed in slab casting are elucidated by referencing to their related flow patterns of molten steel calculated by a multi-field coupling model for actual casting conditions.Eventually,the effect of forced convection on the solidification structure was discussed.The results show that the forced convection generated by electromagnetic stirring and/or nozzle jet will remove the solute-enriched molten steel between the dendrite in front of the solidifying shell,and change solute distribution at the interface of dendrite tips,leading to the white bands and dendrite deflection.In the white band region,a dense dendrite structure without dendrite segregation appears.Moreover,forced convection results in a higher growth rate on the upstream side than the backflow side of the dendrite tip,promoting the columnar crystal deflection.In addition,dendrite fragmentation upon the forced convection during solidification will increase the equiaxed crystal ratio of the as-cast slab and the number of the spot-like semi-macrosegregation.The carbon extreme range decreased with the change in electromagnetic stirring process,indicating a significant improvement in the composition uniformity of the slab casting.It is suggested that the final quality of rolled products could be improved from the very beginning of casting and solidification through regulating the as-cast solidification structure.
基金financial support by the National Natural Science Foundation of China(52174101&52408310)Guangdong Basic and Applied Basic Research Foundation(2023A1515011634&2024A1515012528)Guangdong Provincial Department of Science and Technology(2021ZT09G087)for the research.
文摘The frequent or occasional impact loads pose serious threats to the service safety of conventional concrete structures in tunnel.In this paper,a novel three-dimensional mesoscopic model of steel fiber reinforced concrete(SFRC)is constructed by discrete element method.The model encompasses the concrete matrix,aggregate,interfacial transition zone and steel fibers,taking into account the random shape of the coarse aggregate and the stochastic distribution of steel fibers.It captures microscopic-level interactions among the coarse aggregate,steel fibers,and matrix.Subsequently,a comprehensive procedure is formulated to calibrate the microscopic parameters required by the model,and the reliability of the model is verified by comparing with the experimental results.Furthermore,a coupled finite difference method-discrete element method approach is used to construct the model of the split Hopkinson pressure bar.Compression tests are simulated on SFRC specimens with varying steel fiber contents under static and dynamic loading conditions.Finally,based on the advantages of DEM analysis at the mesoscopic level,this study analyzed mechanisms of enhancement and crack arrest in SFRC.It shed a light on the perspectives of interface failure process,microcrack propagation,contact force field evolution and energy analysis,offering valuable insights for related mining engineering applications.
基金supported by the National Natural Science Foundation of China(Grant No.12272088)the Outstanding Youth Science Foundation of Liaoning Province(Grant No.2024JH3/50100013).
文摘Disk-drum structures jointed by bolted flanges(DDSJBFs)are core parts in aircraft engines,whose dynamic responses affect structural overall safety and service performance.However,studies on the dynamic response of DDSJBFs under base excitation are not found in available literature.In the present work,the dynamic responses for DDSJBFs subjected to base excitation are investigated both theoretically and experimentally.The kinetic energy and potential energy of disk,drum,and flange are derived according to the Kirchhoff plate,the Sanders’shell,and the Euler-Bernoulli beam theories,respectively,where the influences of flange and the mass of bolt are taken into account.The artificial spring method is applied to model the bolted joint.The Chebyshev orthogonal polynomials are adopted as the admissible functions of disk and drum,and the Lagrange equations are used to obtain the motion equation.The motion equation is solved by using the Newmark-beta approach and the dynamic responses under base excitation are acquired.A series of experiment studies are conducted on a DDSJBF to demonstrate the correctness of established theoretical model.Finally,study results show that because the relative motion between bolted flange joint interfaces generates friction damping,increasing the excitation amplitude causes the increase of damping ratio of DDSJBFs on the whole,and the increase of resonant peak value exhibits a slowing trend.The above phenomenon becomes more evident when the number of bolt is less.With the increase of bolt mass and flange size,the resonant frequency significantly decreases,while the resonant peak value remains unchanged.
文摘Revealing the combined influence of interfacial damage and nonlinear factors on the forced vibration is significant for the stability design of fluid-conveying pipes, which are usually assembled in aircraft. The nonlinear forced resonance of fluid-conveying layered pipes with a weak interface and a movable boundary under the external excitation is studied. The pipe is simply supported at both ends, with one end subject to a viscoelastic boundary constraint described by KelvinVoigt model. The weak interface in the pipe is considered in the refined displacement field of the layered pipe employing the interfacial cohesive law. The governing equations are derived by Hamilton's variational principle. Geometric nonlinearities including nonlinear curvature, longitudinal inertia nonlinearity and nonlinear constraint force are comprehensively considered during the theoretical derivation. Amplitude-frequency bifurcation diagrams are obtained utilizing a perturbation-Incremental Harmonic Balance Method(IHBM). Results show that interfacial damage and viscoelastic constraints from boundary and foundation have an important influence on the linear and nonlinear dynamic behavior of the system.
基金supported by the Ignite National Technology fund,under National Grassroots Initiatives Program of ICT R&D(NIGRI),Project ID.NGIRI-2024-23901 of 2024.
文摘This research focuses on developing innovative hybrid solar dryers that combine solar Photovoltaic(PV)and solar thermal systems for sustainable food preservation in Pakistan,addressing the country’s pressing issues of high post-harvest losses and unreliable energy sources.The proposed active hybrid solar dryer features a drying cabinet,two Direct Current(DC)fans for forced convection,and a resistive heating element powered by a 180 W solar PV panel.An energy-storing battery ensures continuous supply to the auxiliaries during periods of low solar irradiance,poor weather conditions,or nighttime.Tomatoes,a delicate and in-demand crop,were selected for experimentation due to their high perishability.Three experiments were conducted on the same prototype:natural convection direct solar dryer(NCDSD),forced convection direct solar dryer(FCDSD),and forced convection hybrid solar dryer(FCHSD).Each experiment began with 0.2 kg of tomatoes at 94%moisture content,achieving significant reductions:28.57%with NCDSD,16.667%with FCDSD,and 16.667%with FCHSD.The observed drying rates varied:1.161 kg/h for NCDSD,2.062 kg/h for FCDSD,and 2.8642 kg/h for FCHSD.This study presents a comparative analysis of efficiency,drying rate,and cost-effectiveness,alongside the system’s economic and environmental feasibility.
文摘The damped Helmholtz-Duffing oscillator is a topic of great interest in many different fields of study due to its complex dynamics.By transitioning from conventional continuous differential equations to their fractal counterparts,one gains insights into the system's response under new mathematical frameworks.This paper presents a novel method for converting standard continuous differential equations into their fractal equivalents.This conversion occurs after the nonlinear system is transformed into its linear equivalent.Numerical analyses show that there are several resonance sites in the fractal system,which differ from the one resonance point found in the continuous system.One important finding is that the fractal system loses some of its stabilizing power when decaying behavior is transformed into a diffuse pattern.Interestingly,a decrease in the fractal order in resonance settings shows a stabilizing impact,highlighting the dynamics'complexity inside fractal systems.This endeavor to convert to fractals is a revolutionary technique that is being employed for the first time.
基金co-supported by the National Natural Science Foundation of China(No.52125504)the Liaoning Revitalization Talents Program(No.XLYC2202017)Dalian Support Policy Project for Innovation of Technological Talents(No.2023RG001)。
文摘The high-quality assembly of Large Aircraft Components(LACs)is essential in modern aviation manufacturing.Numerical control locators are employed for the posture adjustment of LAC,yet the system's multi-input multi-output,nonlinearity,and strong coupling presents significant challenges.The substantial internal force generated during the adjustment process can potentially damage the LAC and degrade the assembly quality.Hence,a workspace-based hybrid force position control scheme was developed to achieve high quality assembly with high-precision and lower internal force.Firstly,an offline workspace analysis with inherent geometric characteristics to form time-varying posture error constraint.Then,the posture error is integrated into the online position axis control to ensure tracking the ideal posture,while the force control axis compensates for posture deviation by minimizing internal force,thereby achieving high precision and low internal force.Finally,the effectiveness was demonstrated through experiments.The root mean square errors of orientation and position are 104 rad and 0.1 mm,respectively.A reduction in internal force can range from 10.96%to 57.4%compared to the traditional method.Key points'max position error is decreased from 0.32 mm to 0.18 mm,satisfying the 0.5 mm tolerance.Therefore,the proposed method will help promote the development of high-performance manufacturing.
基金partially funded by the Ministerio de Relaciones Exteriores del Perú,the Vicerectorado de Investigación of PUCPthe Fondo de Apoyo para la Investigación(FAI)2024 of PUCP.
文摘This study examines radon emissions as potential proxies for environmental change in tropical Andean ecosystems undergoing rapid glacier retreat due to climate forcing.The research was conducted in the proglacial zone of the Yana Ucsha glacier in the Peruvian Andes,where field campaigns between July and November 2023 yielded radon measurements at approximately 28-day intervals across ten monitoring sites(M1-M10).Radon flux was measured using LR115 detectors and complemented by analyses of soil texture and the topographic wetness index(TWI)to assess the influence of environmental variables.Results demonstrate that radon emissions are strongly modulated by soil moisture,which in turn is regulated by regional air temperature and glacier runoff.A significant inverse relationship was identified between radon exhalation and regional air temperature,indicating that warmer periods suppress radon release due to increased soil moisture from enhanced glacier melt.Conversely,the coldest monitoring interval(second period)exhibited markedly higher radon exhalation,reaching up to 0.45 and 0.32 Bq m^(-2)hm^(-1)at sites M1 and M4,respectively-approximately four to five times greater than the baseline range(0-0.10 Bq m^(-2)hm^(-1))observed during other periods.This pronounced temporal anomaly coincided with lower regional air temperatures,reduced glacier runoff,and drier soil conditions,highlighting strong climatic control on radon emissions.These findings suggest that ongoing glacier retreat and climate change may constrain or reduce radon emission rates in Andean proglacial environments,with important implications for environmental monitoring and ecosystem dynamics.Overall,this study provides novel insights into the interactions among cryospheric,atmospheric,and radon dynamics in the tropical Andes.
基金support from the National Natural Science Foundation of China(Grant No.U22A20171)the National Key Research and Development Program Project(2023YFB3709901)+3 种基金the China Baowu Low Carbon Metallurgical Innovation Fund(BWLCF202315)the Pangang-USTB Vanadium and Titanium Research Institute Research Projectthe High Steel Center(HSC)at North China University of TechnologyYanshan University and University of Science and Technology Beijing,China.
文摘Considering the Hamaker constant,inclusion size,and distance between inclusions on the surface of the molten steel,a new collision model of the inclusions on the surface of the molten steel was established based on in-situ observed results of the collision process of different types of inclusions on the surface of the molten steel.The developed model can be used to calculate the attraction of inclusions on the surface of the molten steel including Al_(2)O_(3)MgO,SiO_(2),etc.
基金financial support by the National Key Research and Development Program of China(No.2023YFC2907801)the Hunan Provincial Natural Science Foundation of China(No.2023JJ40760)the Scientific and Technological Project of Yunnan Precious Metals Laboratory,China(No.YPML-2023050276)。
文摘Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.
基金supported by the National Natural Science Foundation of China(Grant No.32371471).
文摘Systematic understanding of the interaction between cells and their microenvironment is of wide interest.To investigate this interaction,a flexible micropillar array device integrating dual functions of cell behavior regulation and adhesion measurement is developed.Micropillar arrays with high and low densities are designed to explore the role of substrate topography in the behavior of human bone marrow mesenchymal stem cells.In addition,a method is established for quantifying weak cell adhesion forces on the basis of micropillar deflections.The results show that cell cytoplasmic adhesion is greater on a low-density micropillar array than that on a high-density array and is localized mainly in the perinuclear region of the cytoplasm rather than in pseudopods.It is also found that the micropillar array topography facilitates the oriented spreading of cell morphology and pseudopod formation,and a reduction in focal adhesion aggregation and F-actin polarization compared with a flat substrate.Notably,cells cultured on a low-density micropillar array exhibited a higher number of pseudopods,stronger adhesion forces,and greater stiffness compared with those on a high-density array.In summary,this work employs an adhesion force sensor,immunofluorescence staining,and atomic force microscopy to investigate the mechanical properties of cells and elucidate the mechanisms by which micropillar topographical cues regulate the adhesion of mesenchymal stem cells to the substrate.The micropillar array force sensor developed in this study provides an effective tool for simultaneously modulating cell behavior and quantifying adhesion forces,offering valuable insights for biomechanical research.
基金supported in part by the Graduate Education Reform Research Project of Hubei University of Technology under Grant 2024YB003the Hubei University of Arts and Science,Teaching Research Project,under Grant JY2025018.
文摘The rapid development of new-quality productive forces(NQPF)has intensified the demand for high-level innovative talent.As a representative of NQPF,generative artificial intelligence(GenAI)offers powerful tools to reshape talent cultivation but also presents significant challenges,including skill hollowing,ethical risks,and a growing disconnect between education and industry needs.Currently,graduate-level software engineering education struggles with outdated curricula and insufficient alignment with practical demands.In this paper,we propose a dual-core collaborative framework driven by“GenAI technology”and“industry demand”.Under this framework,we design a four-dimensional capability development path to enhance graduate students’innovation in software engineering practice.This path focuses on①scientific research innovation,②engineering problem-solving,③cross-domain collaborative evolution,and④ethical risk governance.The proposed approach promotes a shift from traditional knowledge transfer to human-machine collaborative innovation,aligning talent cultivation with the demands of the NQPF.
文摘Against the backdrop of profound restructuring in the global industrial and supply chains,data elements have emerged as a critical force driving the transformation of enterprises'new quality productive forces.To address the ambiguity surrounding its micro-level empowerment mechanism,this paper empirically examines the impact of data elements on enterprises'new quality productive forces and its transmission channels using panel data of Chinese A-share listed firms from 2014 to 2023.The results show that data elements significantly improve the level of enterprises'new quality productive forces.Heterogeneity analysis indicates that this promotional effect is more pronounced in non-state-owned enterprises,large-scale enterprises,and low-leverage enterprises.Mechanism tests confirm that data elements empower new quality productive forces through three paths:enhancing enterprise innovation capability,improving internal operational efficiency,and promoting inter-firm collaboration efficiency.This study provides empirical evidence for understanding the micro-level empowerment logic of data elements and offers theoretical references and practical implications for advancing the deep integration of the digital economy and the real economy.
