Underground hydrogen storage has gained interest in recent years due to the enormous demand for clean energy.Hydrogen is more diffusive than air,with a smaller density and lower viscosity.These unique properties intro...Underground hydrogen storage has gained interest in recent years due to the enormous demand for clean energy.Hydrogen is more diffusive than air,with a smaller density and lower viscosity.These unique properties introduce distinctive hydrodynamic phenomena in hydrogen storage,one of which is fingering.Fingering could induce the fluid trapped in small clusters of pores,leading to a dramatic decrease in hydrogen saturation and a lower recovery rate.In this study,numerical simulations are performed at the microscopic scale to understand the evolution of hydrogen saturation and the impacts of injection and withdrawal cycles.Two sets of micromodels with different porosity(0.362 and 0.426)and minimum sizes of pore throats(0.362 mm and 0.181 mm)are developed in the numerical model.A parameter analysis is then conducted to understand the influence of injection velocity(in the range of 10^(-2)m/s to 10^(-5)m/s)and porous structure on the fingering pattern,followed by an image analysis to capture the evolution of the fingering pattern.Viscous fingering,capillary fingering,and crossover fingering are observed and identified under different boundary conditions.The fractal dimension,specific area,mean angle,and entropy of fingers are proposed as geometric descriptors to characterize the shape of the fingering pattern.When porosity increases from 0.362 to 0.426,the saturation of hydrogen increases by 26.2%.Narrower pore throats elevate capillary resistance,which hinders fluid invasion.These results underscore the importance of pore structures and the interaction between viscous and capillary forces for hydrogen recovery efficiency.This work illuminates the influence of the pore structures and the fluid properties on the immiscible displacement of hydrogen and can be further extended to optimize the injection strategy of hydrogen in underground hydrogen storage.展开更多
A full-scale research study was conducted during the bored tunnelling of the Klang Valley Mass Rapid Transit-Putrajaya Line beneath an existing building structure in Kuala Lumpur,Malaysia.The primary objective was to ...A full-scale research study was conducted during the bored tunnelling of the Klang Valley Mass Rapid Transit-Putrajaya Line beneath an existing building structure in Kuala Lumpur,Malaysia.The primary objective was to investigate the tunnel-soil-pile interaction at various stages of tunnel excavation.This study combined field measurements and three-dimensional(3D)numerical analysis to understand the transient effects of TBM tunnelling on a loaded pile.An experimental pile was instrumented with vibrating wire strain gauges,an inclinometer,and distributed fibre optic sensors using Brillouin optical time domain analysis.The pile was pre-loaded and continuously monitored in real-time throughout the tunnel construction process.The 3D finite element modelling was used to simulate the pile’s transient responses based on actual tunnel boring machine(TBM)driving data.The study revealed that the zone of influence due to tunnelling effects extended from y¼2D to y¼4D,with the peak effect observed at y¼1D to 1.5D,where D represents the tunnel diameter.The analysis of axial load patterns highlighted transient responses,including tensile loads below the tunnel invert,which propagated upward and subsided due to negative skin friction.The maximum downdrag load observed reached 56%e71%of the pile’s working load.Additionally,pile movement patterns indicated outward deflections as the TBM approached and a return toward the tunnel post-passage,aligning with the predicted behaviour in a negative face loss scenario.This validated numerical framework provides a solid foundation for further parametric studies and enhances the understanding of tunnel-soil-pile interactions.展开更多
With the development of urban infrastructure,it is inevitable that shield tunnels will undercross intercity railways.However,the safe operation of intercity railways requires strict subgrade deformation.On the basis o...With the development of urban infrastructure,it is inevitable that shield tunnels will undercross intercity railways.However,the safe operation of intercity railways requires strict subgrade deformation.On the basis of the engineering background of the Lianghu Tunnel in Wuhan,the three-dimensional centrifuge test and numerical back analysis were used to study the development of subgrade surface settlement during shield tunneling.A three-dimensional numerical model with the same size as the prototype was subsequently established to further study the settlement development and torsion behavior of the subgrade during tunnel excavation.The results show that the maximum settlement point of the transverse settlement trough gradually moves to the tunnel axis during tunnel excavation and that the entire subgrade experiences torsional deformation.Moreover,the effect of the intersection angle between the axes of the tunnel and the subgrade on the surface settlement of the subgrade was further studied.The results show that the intersection angle has no effect on the maximum settlement,but the width of the settlement trough increases gradually with increasing angle.Finally,on the basis of the soil arching effect caused by tunnel excavation,the subgrade settlement during tunnel excavation is reduced by reinforcing the soil in different zones of soil arching.The results show that the settlement of the subgrade caused by the shield tunnel can be effectively controlled by adding reinforcement directly to the top of the tunnel,and the maximum settlement of the subgrade surface is reduced from 24.41 mm to 9.47 mm,a reduction of approximately 61.2%.展开更多
This study presents a numerical analysis of the effects of a rigid flat wall with oscillating motion on the pressure wave propagation during a single spherical cavitation bubble collapse at different initial bubble po...This study presents a numerical analysis of the effects of a rigid flat wall with oscillating motion on the pressure wave propagation during a single spherical cavitation bubble collapse at different initial bubble positions.Different nondimensional distances S=0.8,0.9,1.0,1.1,1.2 and 1.3 were considered to investigate the effects of initial in-phase and out-of-phase oscillations of the flat wall.Numerical simulations of cavitation bubble collapse near an oscillating wall were conducted using a compressible two-phase flow model.This model incorporated the Volume of Fluid(VOF)interface-sharpening technique on a general curvilinear moving grid.The numerical results were consistent with published experimental data.The simulation examined the impact of oscillating walls on bubble behavior and the resulting pressure peaks observed on the wall surface.The numerical results demonstrate the significant impact of wall oscillation conditions on bubble collapse and migration behavior,and consequently,the generation of pressure waves with significantly different propagation and pressure peaks induced by shock impact on the rigid wall.Different behaviors were observed in the trendlines of the pressure peaks and maximum jet velocity under in-phase and out-of-phase oscillating walls,with distinct values.At S≥1.0,a higher-pressure peak on the wall was observed in the case of the out-of-phase oscillating condition,whereas a higher-pressure peak was found in the case of the in-phase condition at S<1.0.The highest-pressure peak was found at S=0.8 in trend lines of in-phase and S=1.1 in trend lines of out-of-phase oscillation effects.展开更多
Shotcrete is one of the common solutions for shallow sliding.It works by forming a protective layer with high strength and cementing the loose soil particles on the slope surface to prevent shallow sliding.However,the...Shotcrete is one of the common solutions for shallow sliding.It works by forming a protective layer with high strength and cementing the loose soil particles on the slope surface to prevent shallow sliding.However,the solidification time of conventional cement paste is long when shotcrete is used to treat cohesionless soil landslide.The idea of reinforcing slope with polyurethane solidified soil(i.e.,mixture of polyurethane and sand)was proposed.Model tests and finite element analysis were carried out to study the effectiveness of the proposed new method on the emergency treatment of cohesionless soil landslide.Surcharge loading on the crest of the slope was applied step by step until landslide was triggered so as to test and compare the stability and bearing capacity of slope models with different conditions.The simulated slope displacements were relatively close to the measured results,and the simulated slope deformation characteristics were in good agreement with the observed phenomena,which verifies the accuracy of the numerical method.Under the condition of surcharge loading on the crest of the slope,the unreinforced slope slid when the surcharge loading exceeded 30 k Pa,which presented a failure mode of local instability and collapse at the shallow layer of slope top.The reinforced slope remained stable even when the surcharge loading reached 48 k Pa.The displacement of the reinforced slope was reduced by more than 95%.Overall,this study verifies the effectiveness of polyurethane in the emergency treatment of cohesionless soil landslide and should have broad application prospects in the field of geological disasters concerning the safety of people's live.展开更多
Heat treatment processes, such as annealing and quenching, are crucial in determining residual stress evolution, microstructural changes and mechanical properties of metallic materials, with residual stresses playing ...Heat treatment processes, such as annealing and quenching, are crucial in determining residual stress evolution, microstructural changes and mechanical properties of metallic materials, with residual stresses playing a greater role in the performance of components. This paper investigates the effect of heat treatment on residual stresses induced in AISI 1025, manufactured using LENS. Finite element model was developed and simulated to analyze residual stress development. AISI 1025 samples suitable for tool and die applications in Fused Deposition Modelling (FDM) filament production, were fabricated using Laser Engineered Net Shaping (LENS) process, followed by heat treatment where annealing and quenching processes were done. The material’s microstructure, residual stress and hardness of heat-treated samples under investigation, were compared against the as-built samples. The results indicated that after annealing, tensile residual stresses were reduced by 93%, resulting in a reduced crack growth rate, compared to the as-built sample, although the hardness was reduced significantly by 25%. On the other hand, high tensile residual stresses of 425 ± 14 MPa were recorded after quenching process with an improvement of hardness by 21%.展开更多
Software systems are vulnerable to security breaches as they expand in complexity and functionality.The confidentiality,integrity,and availability of data are gravely threatened by flaws in a system’s design,implemen...Software systems are vulnerable to security breaches as they expand in complexity and functionality.The confidentiality,integrity,and availability of data are gravely threatened by flaws in a system’s design,implementation,or configuration.To guarantee the durability&robustness of the software,vulnerability identification and fixation have become crucial areas of focus for developers,cybersecurity experts and industries.This paper presents a thorough multi-phase mathematical model for efficient patch management and vulnerability detection.To uniquely model these processes,the model incorporated the notion of the learning phenomenon in describing vulnerability fixation using a logistic learning function.Furthermore,the authors have used numerical methods to approximate the solution of the proposed framework where an analytical solution is difficult to attain.The suggested systematic architecture has been demonstrated through statistical analysis using patch datasets,which offers a solid basis for the research conclusions.According to computational research,learning dynamics improves security response and results in more effective vulnerability management.The suggested model offers a systematic approach to proactive vulnerability mitigation and has important uses in risk assessment,software maintenance,and cybersecurity.This study helps create more robust software systems by increasing patch management effectiveness,which benefits developers,cybersecurity experts,and sectors looking to reduce security threats in a growing digital world.展开更多
The internal and external flow fields during vented explosions of methane were characterized through numerical simulation,and the capability of numerical simulation thereof was validated by previous experimental data ...The internal and external flow fields during vented explosions of methane were characterized through numerical simulation,and the capability of numerical simulation thereof was validated by previous experimental data at three ignition positions.The venting mechanism was revealed by the simulated concentration distribution,temperature profile,and airflow velocity.The results show rear ignition results in the external methane mass distribution taking the form of"mushroom"and columnar flames in the external space,which can be expressed as a third-order polynomial relationship with distance;central ignition forms a relationship of the form y=AxB.Front ignition causes the temperature to show a tendency to repeated oscillations(rising,falling,and rising).Central ignition generates the maximum vented airflow velocity(V_(max)=320 m/s)upon vent opening.The results indicate that it is acceptable to apply numerical simulation of methane explosions in practice.展开更多
With the increasing development of deepburied engineering projects,rockburst disasters have become a frequent concern.Studies have indicated that tunnel diameter is a critical factor influencing the occurrence of rock...With the increasing development of deepburied engineering projects,rockburst disasters have become a frequent concern.Studies have indicated that tunnel diameter is a critical factor influencing the occurrence of rockbursts.To investigate the influence of tunnel diameter on the deformation and failure characteristics of surrounding rock,large-sized rocklike gypsum specimens were tested using a selfdeveloped true triaxial rockburst loading system containing circular tunnels with three different diameters(D=0.07 m,0.11 m,and 0.15 m).Acoustic emission monitoring,together with a miniature intelligent camera,was employed to analyze the entire process,focusing on macroscopic failure patterns,fragment characteristics,and underlying failure mechanisms.In addition,theoretical analyses were carried out and combined with numerical simulations to investigate the differences in energy evolution associated with rockburst physical models.The results indicate that:(1)The rockburst process with different tunnel diameters consistently evolved through three distinct stages—initial particle ejection,crack propagation accompanied by flake spalling,and,finally,fragment ejection leading to the formation of a‘V'-shaped notch.(2)Increasing tunnel diameter reduces rockburst failure load while increasing surrounding rock damage extent,total mass and average size of ejected fragments.Additionally,shear failure proportion decreases with tensile failure becoming increasingly dominant.(3)Larger tunnel diameters reduce the attenuation rate of elastic strain energy,thereby expanding the zone of elastic strain energy accumulation and disturbance and creating conditions for larger volume rockburst.(4)Larger tunnel diameters result in a smaller principal stress ratio at equivalent distances in the surrounding rock,indicating a higher likelihood of tensile failure.(5)Numerical analyses further reveal that larger tunnel diameters reduce the maximum elastic strain energy density around the tunnel,lowering the energy released per unit volume of rockburst fragments and their ejection velocities.However,both the total failure volume and overall energy release from rockburst increase.Model experiments with different tunnel diameters are of great significance for optimizing engineering design and parameter selection,as well as guiding tunnel construction under complex geological conditions.展开更多
Conventional geostress evaluation methods often assume static rock properties and neglect the dynamic degradation of mechanical parameters caused by damage evolution during drilling and fracturing processes,which sign...Conventional geostress evaluation methods often assume static rock properties and neglect the dynamic degradation of mechanical parameters caused by damage evolution during drilling and fracturing processes,which significantly limits prediction accuracy.To address this gap,this study develops a multiphysics-coupled numerical framework integrating COMSOL Multiphysics and MATLAB,grounded in damage mechanics theory,to quantitatively investigate the control mechanism of progressive rock damage on geostress redistribution.By establishing a damage constitutive model coupled with thermo-hydro-mechanical interactions,we simulate the dynamic evolution of rock damage and its impact on stress field reorganization during wellbore operations.Key results demonstrate that(1)incorporating damage evolution leads to substantial deviations in both the magnitude and spatial distribution of geostress,with stress perturbations highly localized within damage zones;(2)changes in mechanical parameters-particularly elastic modulus and permeability-dominate stress adjustments,with heightened sensitivity in formations with low elastic moduli and high permeability;and(3)Poisson's ratio has a negligible influence,whereas permeability variation becomes critically important in low-stiffness formations.Field validation via leakage case analyses in the Wujiaping Formation confirms that the proposed method significantly enhances prediction accuracy compared with conventional approaches.This work elucidates the multiscale interdependency between damage and stress evolution by offering a physics-based framework to optimize drilling and stimulation design in heterogeneous reservoirs.展开更多
This study employs the Smoothed Particle Hydrodynamics(SPH)method to develop a computational fluid dynamics(CFD)model for analyzing the interaction between rogue waves and mooring systems.Four floating body configurat...This study employs the Smoothed Particle Hydrodynamics(SPH)method to develop a computational fluid dynamics(CFD)model for analyzing the interaction between rogue waves and mooring systems.Four floating body configurations are investigated:(1)dual rectangular prisms,(2)rectangular prism–sphere composites,(3)sphere–rectangular prism composites,and(4)dual spheres.These configurations are systematically evaluated under varying mooring conditions to assess their hydrodynamic performance and wave attenuation capabilities.The model accurately captures the complex fluid–structure interaction dynamics between moored floating breakwaters and incident wave fields.Among the configurations,the dual rectangular prism system demonstrates superior performance in both wave dissipation and mooring force reduction.Under conditions involving dual wave makers,the influence of floating body shape and number on wave height is found to be minimal.However,dual-body arrangements consistently outperform single-body setups in terms of both energy dissipation and structural stability.From a cost-efficiency perspective,the configuration comprising two rectangular prisms connected via a single mooring system offers significant advantages in material usage and deployment feasibility.展开更多
The pressure wave generated by an urban-rail vehicle when passing through a tunnel affects the comfort of passengersand may even cause damage to the train and related tunnel structures.Therefore,controlling the trains...The pressure wave generated by an urban-rail vehicle when passing through a tunnel affects the comfort of passengersand may even cause damage to the train and related tunnel structures.Therefore,controlling the trainspeed in the tunnel is extremely important.In this study,this problem is investigated numerically in the frameworkof the standard k-εtwo-equation turbulence model.In particular,an eight-car urban rail train passingthrough a tunnel at different speeds(140,160,180 and 200 km/h)is considered.The results show that the maximumaerodynamic drag of the head and tail cars is most affected by the running speed.The pressure at selectedmeasuring points on the windward side of the head car is very high,and the negative pressure at the side windowof the driver’s cab of the tail car is also very large.From the head car to the tail car,the pressure at the same heightgradually decreases.The positive pressure peak at the head car and the negative pressure peak at the tail car aregreatly affected by the speed.展开更多
Enhancing the fermentation efficiency of waste in waste warehouses is pivotal for accelerating the pyrolysis process and minimizing harmful gas emissions.This study proposes an integrated approach,combining hot air in...Enhancing the fermentation efficiency of waste in waste warehouses is pivotal for accelerating the pyrolysis process and minimizing harmful gas emissions.This study proposes an integrated approach,combining hot air injection with dual atomizing nozzles,for the thermal treatment of waste piles.Numerical simulations are employed to investigate the influence of various parameters,namely,nozzle height,nozzle tilt angle,inlet air velocity and air temperature,on the droplet diffusion process,spread area,droplet temperature,and droplet size distribution.The results show that reducing the nozzle height increases the temperature of droplets upon their deposition on the waste pile.Specifically,when the nozzle height is lowered to 1.5 m,the temperature of the droplets reaching the waste pile is 1℃higher than when the nozzle height is set at 2 m.Furthermore,an increase in the nozzle tilt angle expands the overlapping heating area.For instance,when the nozzle angle is increased from 15°to 30°,the overlapping spread area expands by 3.21 m2.Additionally,increasing the inlet air velocity enhances the droplet diffusion range.At an air velocity of 2 m/s,the droplet diffusion range grows to 14.4 m,representing a 6.7%increase compared to the nowind condition.While the average droplet diameter decreases to 1.53 mm,the droplet temperature decreases by 1℃.Moreover,the droplet temperature is found to become smaller as the ambient temperature inside the waste warehouse declines.Specifically,a 5℃reduction in the ambient temperature results in a 1℃decrease in the average temperature of the atomized droplets.The study concludes that a nozzle height of 1.5 m and a nozzle tilt angle of 30°effectively meet practical heating requirements.展开更多
The “3·31” severe squall line event in eastern China was notable for its exceptional intensity and persistence,posing significant challenges to forecast accuracy. This study analyzed the maintenance stage of th...The “3·31” severe squall line event in eastern China was notable for its exceptional intensity and persistence,posing significant challenges to forecast accuracy. This study analyzed the maintenance stage of this event using highresolution convection-permitting numerical simulations, with a focus on vorticity budgets of the environmental flow, multiscale synoptic diagnostics, and Rotunno-Klemp-Weisman(RKW) theory. These analyses aimed to elucidate the mechanisms governing the morphological transition, the generation of associated convective gales, and the prolonged maintenance of the squall line event. The results show that the numerical simulation accurately reproduced the development and evolution of the squall line, particularly its location, with surface wind errors remaining within a reasonable range. The development of a mesoscale vortex modulated the dynamic and water vapor fields, providing favorable mesoscale environmental conditions for the organization and maintenance of the squall line. Vorticity budget analysis indicates that the divergence and tilting terms were the primary contributors to vorticity tendency. After the squall line entered Jiangxi Province, it exhibited a sharper leading edge and enhanced upward motion. Dry intrusion from the mid-toupper troposphere led to rapid downward momentum transfer at the meso-γ scale, thereby generating convective gales. In addition, the enhancement of the rear-inflow jet(RIJ) was related to the pressure difference between the interior and exterior of system, which resulted from the phase change of condensate within tilted updrafts. The RIJ was orthogonal to the squall line, causing it to transform from a linear into a bowing shape. Diagnosis based on the RKW theory underscore the important roles in both low-level and deep vertical wind shear in maintenaning the squall line. The ratios of the cold pool propagation velocity to the vertical wind shear were close to 1, which balanced with the ambient horizontal vorticity that allowed the convection to remain upright, thus sustaining the squall line's intensity for an extended period. In summary, the squall line event was sustained by a favorable environment created by the environmental vortex. The dry intrusion from the mid-to-upper troposphere and intensified RIJ resulted in the severe convective winds, while the balance between cold pool and ambient vertical wind shear promoted the system's prolonged maintenance. These findings provide an effective reference for the short-range forecasting of squall lines throughout their lifecycle.展开更多
This study proposes a novel cyclone separator with a conical inner core to enhance particle classification efficiency in oil and gas wellhead-recovered liquids.Particle motion and force dynamics are analyzed to optimi...This study proposes a novel cyclone separator with a conical inner core to enhance particle classification efficiency in oil and gas wellhead-recovered liquids.Particle motion and force dynamics are analyzed to optimize key structural parameters,including inlet diameter(D_i),overflow pipe diameter(D_(e)),insertion depth(L_(e)),and bottom flow pipe diameter(D_(z)).Numerical simulations employ the Reynolds stress turbulence model,SIMPLEC algorithm,and discrete phase model to evaluate separation performance in a gas-liquid two-phase system.Results indicate that a smaller D_i improves fine particle separation but increases turbulence;an optimal range of D_i/D_(c)=0.35-0.4 is recommended.Larger D_(e) enhances the diversion ratio,aiding fine particle discharge(D_(e)/D_(c)=0.25-0.35).Increased Le facilitates fine particle overflow but induces vortices,whereas a smaller L_(e) stabilizes the bottom flow for larger particle separation(L_(e)/D_(c)=0.5-0.75).A reduced D_(z) enhances centrifugal force and separation efficiency but may cause turbulence;an optimal D_(z)/D_(c) of 0.6-0.65 is suggested for stability.These findings provide valuable design guidelines for improving cyclone separator performance in multiphase flow applications.展开更多
Both the complex geometrical morphology of rough-walled rock fractures and the nonlinearity of fluid flow contribute to resistance in fluid flow through rock fractures.The interactions of the shear-flow process furthe...Both the complex geometrical morphology of rough-walled rock fractures and the nonlinearity of fluid flow contribute to resistance in fluid flow through rock fractures.The interactions of the shear-flow process further complicate the characterisation of flow behaviours in rock fractures.In this study,an improved friction factor model involving both the effects of viscous and inertial forces is presented based on the Forchheimer equation.The model incorporates two key variables,i.e.Reynolds number and relative roughness,which reflect the effects of flow regimes and fracture roughness,respectively.The changes in geometrical parameters induced by shearing are considered,with the peak asperity height predicted through a correlation with post-peak roughness degradation.The hydraulic aperture during shearing is estimated using a suggested equation that accounts for the mobilised contact area ratio and variable aperture distribution.The parametric sensitivity analysis reveals that shear-induced changes in fracture geometry enhance the flow nonlinearity in rock fractures.The model performs well in predicting the friction factor based on two validation criteria.Then,the proposed friction factor model is incorporated into the three-dimensional distinct element code(3DEC)in the form of the Darcy-Weisbach equation.Coupled with the numerically implemented mechanical model and hydraulic aperture prediction model,numerical simulations of coupled shear-flow processes in single rock fractures are conducted.The simulation outcomes are validated through comparison with the experimental results,showing acceptable agreement and demonstrating that the numerical model is capable of accurately evaluating the hydro-mechanical coupling behaviour during the shearing of rock fractures.展开更多
Produced water reinjection is a common strategy in offshore oilfield operations,yet the presence of solid particles in produced water can lead to localized formation pressure buildup,increasing the risk of rock fractu...Produced water reinjection is a common strategy in offshore oilfield operations,yet the presence of solid particles in produced water can lead to localized formation pressure buildup,increasing the risk of rock fracturing and leakage.In this study,we present an integrated experimental and numerical investigation to quantify the effects of particle migration on formation pressure and the spatial diffusion of injected water.Dynamic plugging experiments were performed to systematically examine the influence of injection rate and injection volume on core permeability.Results demonstrate that higher injection rates substantially reduce permeability,and the derived relationship between permeability and injection volume enables dynamic assessment of permeability evolution during reinjection.Complementary numerical simulations explored the impacts of injection length,particle concentration,and injection rate on formation pressure and diffusion behavior.Findings indicate that extending the injection section promotes pressure distribution and enlarges the diffusion area,whereas elevated particle concentrations and injection rates accelerate formation plugging,causing rapid pressure rise and constrained diffusion.展开更多
A self-centering bridge bent equipped with energy-dissipation(ED)beams is proposed.Quasi-static tests are conducted on self-centering bridge bents,both with and without ED beams,to validate the accuracy of the corresp...A self-centering bridge bent equipped with energy-dissipation(ED)beams is proposed.Quasi-static tests are conducted on self-centering bridge bents,both with and without ED beams,to validate the accuracy of the corresponding numerical models.The effects of various param-eters,such as the web area of ED beams,prestressing force of tendons,tendon arrangements,and number of column segments,on the seismic performance of self-centering bridge bents with ED beams are evaluated using the validated numerical model.The results demonstrate that the nu-merical models accurately replicate the quasi-static test results,with average errors in the lateral force remaining below 9.6%.The web area of ED beams significantly affects the strength,cumulative energy dissipation,and relative self-centering index(RSI)of the self-centering bridge bents.Increasing the prestressing force enhances the lateral force and self-centering capability of the bridge bents but has minimal effect on their ED capacity.Reducing the num-ber of segments in each column enhances the lateral force and cumulative hysteretic energy dissipation of the self-centering bridge bents while exerting an insignificant effect on the RSI.Thus,the proposed novel system is highly suitable for doubleor multicolumn piers supporting bridges in regions prone to strong earthquakes.展开更多
Shale gas reservoirs have large burial depths,thin thickness,and low resistance,which lead to problems with weak surface observation,abnormal information,and multiple inversion solutions.The traditional electromagneti...Shale gas reservoirs have large burial depths,thin thickness,and low resistance,which lead to problems with weak surface observation,abnormal information,and multiple inversion solutions.The traditional electromagnetic method cannot effectively identify information from deep,low-resistance thin layers in terms of detection depth and accuracy.Wide field electromagnetic method(WFEM)with large depth and high precision has become the main method for deep earth exploration.This method has been widely used in the exploration of deep oil and gas energy,as well as mineral resources.However,an in-depth analysis of the various factors that affect the deep detection ability of WFEM is lacking.Therefore,the analysis of system parameters has significant theoretical importance and practical value for studying the effectiveness of WFEM in deep-layer identification.In this study,a multilayer geoelectric model is established in this study using the measured well data.The influence characteristics of different observation system parameters on the resolution of specific deep-seated targets under the WFEM_E-Ex mode are analyzed in detail through forward modeling and inversion.Results show that the resolution ability of WFEM for deep,low-resistance thin layers is affected by factors such as transceiver distance,target layer thickness,and resistivity difference between the target body and the surrounding rock,but the influence range differs.This study analyzes the influence characteristics of various system parameters.It provides targeted work scheme design and feasibility analysis for deep shale gas exploration.It also offers an important theoretical basis for optimizing construction schemes and improving the recognition ability of WFEM for deep,low-resistance targets.展开更多
Border-associated macrophages are located at the interface between the brain and the periphery, including the perivascular spaces, choroid plexus, and meninges. Until recently, the functions of border-associated macro...Border-associated macrophages are located at the interface between the brain and the periphery, including the perivascular spaces, choroid plexus, and meninges. Until recently, the functions of border-associated macrophages have been poorly understood and largely overlooked. However, a recent study reported that border-associated macrophages participate in stroke-induced inflammation, although many details and the underlying mechanisms remain unclear. In this study, we performed a comprehensive single-cell analysis of mouse border-associated macrophages using sequencing data obtained from the Gene Expression Omnibus(GEO) database(GSE174574 and GSE225948). Differentially expressed genes were identified, and enrichment analysis was performed to identify the transcription profile of border-associated macrophages. CellChat analysis was conducted to determine the cell communication network of border-associated macrophages. Transcription factors were predicted using the ‘pySCENIC' tool. We found that, in response to hypoxia, borderassociated macrophages underwent dynamic transcriptional changes and participated in the regulation of inflammatory-related pathways. Notably, the tumor necrosis factor pathway was activated by border-associated macrophages following ischemic stroke. The pySCENIC analysis indicated that the activity of signal transducer and activator of transcription 3(Stat3) was obviously upregulated in stroke, suggesting that Stat3 inhibition may be a promising strategy for treating border-associated macrophages-induced neuroinflammation. Finally, we constructed an animal model to investigate the effects of border-associated macrophages depletion following a stroke. Treatment with liposomes containing clodronate significantly reduced infarct volume in the animals and improved neurological scores compared with untreated animals. Taken together, our results demonstrate comprehensive changes in border-associated macrophages following a stroke, providing a theoretical basis for targeting border-associated macrophages-induced neuroinflammation in stroke treatment.展开更多
基金supported by the National Key Research and Development Project(Grant No.2023YFE0110900)the National Natural Science Foundation of China(Grant Nos.42320104003,42477168).
文摘Underground hydrogen storage has gained interest in recent years due to the enormous demand for clean energy.Hydrogen is more diffusive than air,with a smaller density and lower viscosity.These unique properties introduce distinctive hydrodynamic phenomena in hydrogen storage,one of which is fingering.Fingering could induce the fluid trapped in small clusters of pores,leading to a dramatic decrease in hydrogen saturation and a lower recovery rate.In this study,numerical simulations are performed at the microscopic scale to understand the evolution of hydrogen saturation and the impacts of injection and withdrawal cycles.Two sets of micromodels with different porosity(0.362 and 0.426)and minimum sizes of pore throats(0.362 mm and 0.181 mm)are developed in the numerical model.A parameter analysis is then conducted to understand the influence of injection velocity(in the range of 10^(-2)m/s to 10^(-5)m/s)and porous structure on the fingering pattern,followed by an image analysis to capture the evolution of the fingering pattern.Viscous fingering,capillary fingering,and crossover fingering are observed and identified under different boundary conditions.The fractal dimension,specific area,mean angle,and entropy of fingers are proposed as geometric descriptors to characterize the shape of the fingering pattern.When porosity increases from 0.362 to 0.426,the saturation of hydrogen increases by 26.2%.Narrower pore throats elevate capillary resistance,which hinders fluid invasion.These results underscore the importance of pore structures and the interaction between viscous and capillary forces for hydrogen recovery efficiency.This work illuminates the influence of the pore structures and the fluid properties on the immiscible displacement of hydrogen and can be further extended to optimize the injection strategy of hydrogen in underground hydrogen storage.
文摘A full-scale research study was conducted during the bored tunnelling of the Klang Valley Mass Rapid Transit-Putrajaya Line beneath an existing building structure in Kuala Lumpur,Malaysia.The primary objective was to investigate the tunnel-soil-pile interaction at various stages of tunnel excavation.This study combined field measurements and three-dimensional(3D)numerical analysis to understand the transient effects of TBM tunnelling on a loaded pile.An experimental pile was instrumented with vibrating wire strain gauges,an inclinometer,and distributed fibre optic sensors using Brillouin optical time domain analysis.The pile was pre-loaded and continuously monitored in real-time throughout the tunnel construction process.The 3D finite element modelling was used to simulate the pile’s transient responses based on actual tunnel boring machine(TBM)driving data.The study revealed that the zone of influence due to tunnelling effects extended from y¼2D to y¼4D,with the peak effect observed at y¼1D to 1.5D,where D represents the tunnel diameter.The analysis of axial load patterns highlighted transient responses,including tensile loads below the tunnel invert,which propagated upward and subsided due to negative skin friction.The maximum downdrag load observed reached 56%e71%of the pile’s working load.Additionally,pile movement patterns indicated outward deflections as the TBM approached and a return toward the tunnel post-passage,aligning with the predicted behaviour in a negative face loss scenario.This validated numerical framework provides a solid foundation for further parametric studies and enhances the understanding of tunnel-soil-pile interactions.
基金funding support from the National Natural Science Foundation of China(Grant Nos.52208355and 52378308)Shenzhen University's 2035 Program for Excellent Research(Grant No.00000219).
文摘With the development of urban infrastructure,it is inevitable that shield tunnels will undercross intercity railways.However,the safe operation of intercity railways requires strict subgrade deformation.On the basis of the engineering background of the Lianghu Tunnel in Wuhan,the three-dimensional centrifuge test and numerical back analysis were used to study the development of subgrade surface settlement during shield tunneling.A three-dimensional numerical model with the same size as the prototype was subsequently established to further study the settlement development and torsion behavior of the subgrade during tunnel excavation.The results show that the maximum settlement point of the transverse settlement trough gradually moves to the tunnel axis during tunnel excavation and that the entire subgrade experiences torsional deformation.Moreover,the effect of the intersection angle between the axes of the tunnel and the subgrade on the surface settlement of the subgrade was further studied.The results show that the intersection angle has no effect on the maximum settlement,but the width of the settlement trough increases gradually with increasing angle.Finally,on the basis of the soil arching effect caused by tunnel excavation,the subgrade settlement during tunnel excavation is reduced by reinforcing the soil in different zones of soil arching.The results show that the settlement of the subgrade caused by the shield tunnel can be effectively controlled by adding reinforcement directly to the top of the tunnel,and the maximum settlement of the subgrade surface is reduced from 24.41 mm to 9.47 mm,a reduction of approximately 61.2%.
基金sponsored by the Vietnam Academy of Science and Technology(VAST),granted to Prof.Duong Ngoc Hai under Project No.VAST01.02/22-23by the National Research Foundation(NRF)of the Republic of Korea,granted to Prof.Warn-Gyu Park under Project No.RS-2023-00248070.
文摘This study presents a numerical analysis of the effects of a rigid flat wall with oscillating motion on the pressure wave propagation during a single spherical cavitation bubble collapse at different initial bubble positions.Different nondimensional distances S=0.8,0.9,1.0,1.1,1.2 and 1.3 were considered to investigate the effects of initial in-phase and out-of-phase oscillations of the flat wall.Numerical simulations of cavitation bubble collapse near an oscillating wall were conducted using a compressible two-phase flow model.This model incorporated the Volume of Fluid(VOF)interface-sharpening technique on a general curvilinear moving grid.The numerical results were consistent with published experimental data.The simulation examined the impact of oscillating walls on bubble behavior and the resulting pressure peaks observed on the wall surface.The numerical results demonstrate the significant impact of wall oscillation conditions on bubble collapse and migration behavior,and consequently,the generation of pressure waves with significantly different propagation and pressure peaks induced by shock impact on the rigid wall.Different behaviors were observed in the trendlines of the pressure peaks and maximum jet velocity under in-phase and out-of-phase oscillating walls,with distinct values.At S≥1.0,a higher-pressure peak on the wall was observed in the case of the out-of-phase oscillating condition,whereas a higher-pressure peak was found in the case of the in-phase condition at S<1.0.The highest-pressure peak was found at S=0.8 in trend lines of in-phase and S=1.1 in trend lines of out-of-phase oscillation effects.
基金the financial support from the Fujian Science Foundation for Outstanding Youth(2023J06039)the National Natural Science Foundation of China(Grant No.41977259,U2005205,41972268)the Independent Research Project of Technology Innovation Center for Monitoring and Restoration Engineering of Ecological Fragile Zone in Southeast China(KY-090000-04-2022-019)。
文摘Shotcrete is one of the common solutions for shallow sliding.It works by forming a protective layer with high strength and cementing the loose soil particles on the slope surface to prevent shallow sliding.However,the solidification time of conventional cement paste is long when shotcrete is used to treat cohesionless soil landslide.The idea of reinforcing slope with polyurethane solidified soil(i.e.,mixture of polyurethane and sand)was proposed.Model tests and finite element analysis were carried out to study the effectiveness of the proposed new method on the emergency treatment of cohesionless soil landslide.Surcharge loading on the crest of the slope was applied step by step until landslide was triggered so as to test and compare the stability and bearing capacity of slope models with different conditions.The simulated slope displacements were relatively close to the measured results,and the simulated slope deformation characteristics were in good agreement with the observed phenomena,which verifies the accuracy of the numerical method.Under the condition of surcharge loading on the crest of the slope,the unreinforced slope slid when the surcharge loading exceeded 30 k Pa,which presented a failure mode of local instability and collapse at the shallow layer of slope top.The reinforced slope remained stable even when the surcharge loading reached 48 k Pa.The displacement of the reinforced slope was reduced by more than 95%.Overall,this study verifies the effectiveness of polyurethane in the emergency treatment of cohesionless soil landslide and should have broad application prospects in the field of geological disasters concerning the safety of people's live.
文摘Heat treatment processes, such as annealing and quenching, are crucial in determining residual stress evolution, microstructural changes and mechanical properties of metallic materials, with residual stresses playing a greater role in the performance of components. This paper investigates the effect of heat treatment on residual stresses induced in AISI 1025, manufactured using LENS. Finite element model was developed and simulated to analyze residual stress development. AISI 1025 samples suitable for tool and die applications in Fused Deposition Modelling (FDM) filament production, were fabricated using Laser Engineered Net Shaping (LENS) process, followed by heat treatment where annealing and quenching processes were done. The material’s microstructure, residual stress and hardness of heat-treated samples under investigation, were compared against the as-built samples. The results indicated that after annealing, tensile residual stresses were reduced by 93%, resulting in a reduced crack growth rate, compared to the as-built sample, although the hardness was reduced significantly by 25%. On the other hand, high tensile residual stresses of 425 ± 14 MPa were recorded after quenching process with an improvement of hardness by 21%.
基金supported by grants received by the first author and third author from the Institute of Eminence,Delhi University,Delhi,India,as part of the Faculty Research Program via Ref.No./IoE/2024-25/12/FRP.
文摘Software systems are vulnerable to security breaches as they expand in complexity and functionality.The confidentiality,integrity,and availability of data are gravely threatened by flaws in a system’s design,implementation,or configuration.To guarantee the durability&robustness of the software,vulnerability identification and fixation have become crucial areas of focus for developers,cybersecurity experts and industries.This paper presents a thorough multi-phase mathematical model for efficient patch management and vulnerability detection.To uniquely model these processes,the model incorporated the notion of the learning phenomenon in describing vulnerability fixation using a logistic learning function.Furthermore,the authors have used numerical methods to approximate the solution of the proposed framework where an analytical solution is difficult to attain.The suggested systematic architecture has been demonstrated through statistical analysis using patch datasets,which offers a solid basis for the research conclusions.According to computational research,learning dynamics improves security response and results in more effective vulnerability management.The suggested model offers a systematic approach to proactive vulnerability mitigation and has important uses in risk assessment,software maintenance,and cybersecurity.This study helps create more robust software systems by increasing patch management effectiveness,which benefits developers,cybersecurity experts,and sectors looking to reduce security threats in a growing digital world.
基金supported by the Young Scientists Fund of National Natural Science Foundation of China(Grant Nos.12202202 and 12202494)the National Key Research and Development Program of China(Grant No.2021YFC3100700)。
文摘The internal and external flow fields during vented explosions of methane were characterized through numerical simulation,and the capability of numerical simulation thereof was validated by previous experimental data at three ignition positions.The venting mechanism was revealed by the simulated concentration distribution,temperature profile,and airflow velocity.The results show rear ignition results in the external methane mass distribution taking the form of"mushroom"and columnar flames in the external space,which can be expressed as a third-order polynomial relationship with distance;central ignition forms a relationship of the form y=AxB.Front ignition causes the temperature to show a tendency to repeated oscillations(rising,falling,and rising).Central ignition generates the maximum vented airflow velocity(V_(max)=320 m/s)upon vent opening.The results indicate that it is acceptable to apply numerical simulation of methane explosions in practice.
基金funded by the National Natural Science Foundation of China(Nos.42077228,52174085)。
文摘With the increasing development of deepburied engineering projects,rockburst disasters have become a frequent concern.Studies have indicated that tunnel diameter is a critical factor influencing the occurrence of rockbursts.To investigate the influence of tunnel diameter on the deformation and failure characteristics of surrounding rock,large-sized rocklike gypsum specimens were tested using a selfdeveloped true triaxial rockburst loading system containing circular tunnels with three different diameters(D=0.07 m,0.11 m,and 0.15 m).Acoustic emission monitoring,together with a miniature intelligent camera,was employed to analyze the entire process,focusing on macroscopic failure patterns,fragment characteristics,and underlying failure mechanisms.In addition,theoretical analyses were carried out and combined with numerical simulations to investigate the differences in energy evolution associated with rockburst physical models.The results indicate that:(1)The rockburst process with different tunnel diameters consistently evolved through three distinct stages—initial particle ejection,crack propagation accompanied by flake spalling,and,finally,fragment ejection leading to the formation of a‘V'-shaped notch.(2)Increasing tunnel diameter reduces rockburst failure load while increasing surrounding rock damage extent,total mass and average size of ejected fragments.Additionally,shear failure proportion decreases with tensile failure becoming increasingly dominant.(3)Larger tunnel diameters reduce the attenuation rate of elastic strain energy,thereby expanding the zone of elastic strain energy accumulation and disturbance and creating conditions for larger volume rockburst.(4)Larger tunnel diameters result in a smaller principal stress ratio at equivalent distances in the surrounding rock,indicating a higher likelihood of tensile failure.(5)Numerical analyses further reveal that larger tunnel diameters reduce the maximum elastic strain energy density around the tunnel,lowering the energy released per unit volume of rockburst fragments and their ejection velocities.However,both the total failure volume and overall energy release from rockburst increase.Model experiments with different tunnel diameters are of great significance for optimizing engineering design and parameter selection,as well as guiding tunnel construction under complex geological conditions.
基金supported by Science Project of PetroChina Southwest Oil&Gas field Company,China(Grant.No:2024D112-01-02).
文摘Conventional geostress evaluation methods often assume static rock properties and neglect the dynamic degradation of mechanical parameters caused by damage evolution during drilling and fracturing processes,which significantly limits prediction accuracy.To address this gap,this study develops a multiphysics-coupled numerical framework integrating COMSOL Multiphysics and MATLAB,grounded in damage mechanics theory,to quantitatively investigate the control mechanism of progressive rock damage on geostress redistribution.By establishing a damage constitutive model coupled with thermo-hydro-mechanical interactions,we simulate the dynamic evolution of rock damage and its impact on stress field reorganization during wellbore operations.Key results demonstrate that(1)incorporating damage evolution leads to substantial deviations in both the magnitude and spatial distribution of geostress,with stress perturbations highly localized within damage zones;(2)changes in mechanical parameters-particularly elastic modulus and permeability-dominate stress adjustments,with heightened sensitivity in formations with low elastic moduli and high permeability;and(3)Poisson's ratio has a negligible influence,whereas permeability variation becomes critically important in low-stiffness formations.Field validation via leakage case analyses in the Wujiaping Formation confirms that the proposed method significantly enhances prediction accuracy compared with conventional approaches.This work elucidates the multiscale interdependency between damage and stress evolution by offering a physics-based framework to optimize drilling and stimulation design in heterogeneous reservoirs.
基金funding from the National Natural Science Foundation of China(No.12462028).
文摘This study employs the Smoothed Particle Hydrodynamics(SPH)method to develop a computational fluid dynamics(CFD)model for analyzing the interaction between rogue waves and mooring systems.Four floating body configurations are investigated:(1)dual rectangular prisms,(2)rectangular prism–sphere composites,(3)sphere–rectangular prism composites,and(4)dual spheres.These configurations are systematically evaluated under varying mooring conditions to assess their hydrodynamic performance and wave attenuation capabilities.The model accurately captures the complex fluid–structure interaction dynamics between moored floating breakwaters and incident wave fields.Among the configurations,the dual rectangular prism system demonstrates superior performance in both wave dissipation and mooring force reduction.Under conditions involving dual wave makers,the influence of floating body shape and number on wave height is found to be minimal.However,dual-body arrangements consistently outperform single-body setups in terms of both energy dissipation and structural stability.From a cost-efficiency perspective,the configuration comprising two rectangular prisms connected via a single mooring system offers significant advantages in material usage and deployment feasibility.
基金supported by the Beijing Postdoctoral Research Foundation(No.2023-ZZ-133)Scientific Research Foundation of Beijing Infrastructure Investment Co.,Ltd.(No.2023-ZB-03)Fundamental Research Funds for the Central Universities(No.2682023ZTPY036).
文摘The pressure wave generated by an urban-rail vehicle when passing through a tunnel affects the comfort of passengersand may even cause damage to the train and related tunnel structures.Therefore,controlling the trainspeed in the tunnel is extremely important.In this study,this problem is investigated numerically in the frameworkof the standard k-εtwo-equation turbulence model.In particular,an eight-car urban rail train passingthrough a tunnel at different speeds(140,160,180 and 200 km/h)is considered.The results show that the maximumaerodynamic drag of the head and tail cars is most affected by the running speed.The pressure at selectedmeasuring points on the windward side of the head car is very high,and the negative pressure at the side windowof the driver’s cab of the tail car is also very large.From the head car to the tail car,the pressure at the same heightgradually decreases.The positive pressure peak at the head car and the negative pressure peak at the tail car aregreatly affected by the speed.
文摘Enhancing the fermentation efficiency of waste in waste warehouses is pivotal for accelerating the pyrolysis process and minimizing harmful gas emissions.This study proposes an integrated approach,combining hot air injection with dual atomizing nozzles,for the thermal treatment of waste piles.Numerical simulations are employed to investigate the influence of various parameters,namely,nozzle height,nozzle tilt angle,inlet air velocity and air temperature,on the droplet diffusion process,spread area,droplet temperature,and droplet size distribution.The results show that reducing the nozzle height increases the temperature of droplets upon their deposition on the waste pile.Specifically,when the nozzle height is lowered to 1.5 m,the temperature of the droplets reaching the waste pile is 1℃higher than when the nozzle height is set at 2 m.Furthermore,an increase in the nozzle tilt angle expands the overlapping heating area.For instance,when the nozzle angle is increased from 15°to 30°,the overlapping spread area expands by 3.21 m2.Additionally,increasing the inlet air velocity enhances the droplet diffusion range.At an air velocity of 2 m/s,the droplet diffusion range grows to 14.4 m,representing a 6.7%increase compared to the nowind condition.While the average droplet diameter decreases to 1.53 mm,the droplet temperature decreases by 1℃.Moreover,the droplet temperature is found to become smaller as the ambient temperature inside the waste warehouse declines.Specifically,a 5℃reduction in the ambient temperature results in a 1℃decrease in the average temperature of the atomized droplets.The study concludes that a nozzle height of 1.5 m and a nozzle tilt angle of 30°effectively meet practical heating requirements.
基金Jiangxi Meteorological Bureau Project (JXCX202304,JX2024Y01)Geological Disaster Prevention and Control Project of Jiangxi Provincial Department of Natural Resources(B360000030004)+1 种基金Key Research and Development Project of Jiangxi Province (20243BBH81005)Weather Review Project of China Meteorological Administration (FPZJ2025-066)。
文摘The “3·31” severe squall line event in eastern China was notable for its exceptional intensity and persistence,posing significant challenges to forecast accuracy. This study analyzed the maintenance stage of this event using highresolution convection-permitting numerical simulations, with a focus on vorticity budgets of the environmental flow, multiscale synoptic diagnostics, and Rotunno-Klemp-Weisman(RKW) theory. These analyses aimed to elucidate the mechanisms governing the morphological transition, the generation of associated convective gales, and the prolonged maintenance of the squall line event. The results show that the numerical simulation accurately reproduced the development and evolution of the squall line, particularly its location, with surface wind errors remaining within a reasonable range. The development of a mesoscale vortex modulated the dynamic and water vapor fields, providing favorable mesoscale environmental conditions for the organization and maintenance of the squall line. Vorticity budget analysis indicates that the divergence and tilting terms were the primary contributors to vorticity tendency. After the squall line entered Jiangxi Province, it exhibited a sharper leading edge and enhanced upward motion. Dry intrusion from the mid-toupper troposphere led to rapid downward momentum transfer at the meso-γ scale, thereby generating convective gales. In addition, the enhancement of the rear-inflow jet(RIJ) was related to the pressure difference between the interior and exterior of system, which resulted from the phase change of condensate within tilted updrafts. The RIJ was orthogonal to the squall line, causing it to transform from a linear into a bowing shape. Diagnosis based on the RKW theory underscore the important roles in both low-level and deep vertical wind shear in maintenaning the squall line. The ratios of the cold pool propagation velocity to the vertical wind shear were close to 1, which balanced with the ambient horizontal vorticity that allowed the convection to remain upright, thus sustaining the squall line's intensity for an extended period. In summary, the squall line event was sustained by a favorable environment created by the environmental vortex. The dry intrusion from the mid-to-upper troposphere and intensified RIJ resulted in the severe convective winds, while the balance between cold pool and ambient vertical wind shear promoted the system's prolonged maintenance. These findings provide an effective reference for the short-range forecasting of squall lines throughout their lifecycle.
基金supported by the National Natural Science Foundation of China(52074341)。
文摘This study proposes a novel cyclone separator with a conical inner core to enhance particle classification efficiency in oil and gas wellhead-recovered liquids.Particle motion and force dynamics are analyzed to optimize key structural parameters,including inlet diameter(D_i),overflow pipe diameter(D_(e)),insertion depth(L_(e)),and bottom flow pipe diameter(D_(z)).Numerical simulations employ the Reynolds stress turbulence model,SIMPLEC algorithm,and discrete phase model to evaluate separation performance in a gas-liquid two-phase system.Results indicate that a smaller D_i improves fine particle separation but increases turbulence;an optimal range of D_i/D_(c)=0.35-0.4 is recommended.Larger D_(e) enhances the diversion ratio,aiding fine particle discharge(D_(e)/D_(c)=0.25-0.35).Increased Le facilitates fine particle overflow but induces vortices,whereas a smaller L_(e) stabilizes the bottom flow for larger particle separation(L_(e)/D_(c)=0.5-0.75).A reduced D_(z) enhances centrifugal force and separation efficiency but may cause turbulence;an optimal D_(z)/D_(c) of 0.6-0.65 is suggested for stability.These findings provide valuable design guidelines for improving cyclone separator performance in multiphase flow applications.
基金supported by the China Scholarship Council(CSC)(Grant No.202006060033).
文摘Both the complex geometrical morphology of rough-walled rock fractures and the nonlinearity of fluid flow contribute to resistance in fluid flow through rock fractures.The interactions of the shear-flow process further complicate the characterisation of flow behaviours in rock fractures.In this study,an improved friction factor model involving both the effects of viscous and inertial forces is presented based on the Forchheimer equation.The model incorporates two key variables,i.e.Reynolds number and relative roughness,which reflect the effects of flow regimes and fracture roughness,respectively.The changes in geometrical parameters induced by shearing are considered,with the peak asperity height predicted through a correlation with post-peak roughness degradation.The hydraulic aperture during shearing is estimated using a suggested equation that accounts for the mobilised contact area ratio and variable aperture distribution.The parametric sensitivity analysis reveals that shear-induced changes in fracture geometry enhance the flow nonlinearity in rock fractures.The model performs well in predicting the friction factor based on two validation criteria.Then,the proposed friction factor model is incorporated into the three-dimensional distinct element code(3DEC)in the form of the Darcy-Weisbach equation.Coupled with the numerically implemented mechanical model and hydraulic aperture prediction model,numerical simulations of coupled shear-flow processes in single rock fractures are conducted.The simulation outcomes are validated through comparison with the experimental results,showing acceptable agreement and demonstrating that the numerical model is capable of accurately evaluating the hydro-mechanical coupling behaviour during the shearing of rock fractures.
基金supported by the National Natural Science Foundation of China(No.52204026).
文摘Produced water reinjection is a common strategy in offshore oilfield operations,yet the presence of solid particles in produced water can lead to localized formation pressure buildup,increasing the risk of rock fracturing and leakage.In this study,we present an integrated experimental and numerical investigation to quantify the effects of particle migration on formation pressure and the spatial diffusion of injected water.Dynamic plugging experiments were performed to systematically examine the influence of injection rate and injection volume on core permeability.Results demonstrate that higher injection rates substantially reduce permeability,and the derived relationship between permeability and injection volume enables dynamic assessment of permeability evolution during reinjection.Complementary numerical simulations explored the impacts of injection length,particle concentration,and injection rate on formation pressure and diffusion behavior.Findings indicate that extending the injection section promotes pressure distribution and enlarges the diffusion area,whereas elevated particle concentrations and injection rates accelerate formation plugging,causing rapid pressure rise and constrained diffusion.
基金The National Natural Science Foundation of China(No.52278189)Zhejiang Provincial Natural Science Foundation of China(No.LY24E080002).
文摘A self-centering bridge bent equipped with energy-dissipation(ED)beams is proposed.Quasi-static tests are conducted on self-centering bridge bents,both with and without ED beams,to validate the accuracy of the corresponding numerical models.The effects of various param-eters,such as the web area of ED beams,prestressing force of tendons,tendon arrangements,and number of column segments,on the seismic performance of self-centering bridge bents with ED beams are evaluated using the validated numerical model.The results demonstrate that the nu-merical models accurately replicate the quasi-static test results,with average errors in the lateral force remaining below 9.6%.The web area of ED beams significantly affects the strength,cumulative energy dissipation,and relative self-centering index(RSI)of the self-centering bridge bents.Increasing the prestressing force enhances the lateral force and self-centering capability of the bridge bents but has minimal effect on their ED capacity.Reducing the num-ber of segments in each column enhances the lateral force and cumulative hysteretic energy dissipation of the self-centering bridge bents while exerting an insignificant effect on the RSI.Thus,the proposed novel system is highly suitable for doubleor multicolumn piers supporting bridges in regions prone to strong earthquakes.
基金supported by the Jingdezhen Science and Technology Plan Project(No.20234SF005)the Jingdezhen University Science and Technology Project(No.2023xjkt-02).
文摘Shale gas reservoirs have large burial depths,thin thickness,and low resistance,which lead to problems with weak surface observation,abnormal information,and multiple inversion solutions.The traditional electromagnetic method cannot effectively identify information from deep,low-resistance thin layers in terms of detection depth and accuracy.Wide field electromagnetic method(WFEM)with large depth and high precision has become the main method for deep earth exploration.This method has been widely used in the exploration of deep oil and gas energy,as well as mineral resources.However,an in-depth analysis of the various factors that affect the deep detection ability of WFEM is lacking.Therefore,the analysis of system parameters has significant theoretical importance and practical value for studying the effectiveness of WFEM in deep-layer identification.In this study,a multilayer geoelectric model is established in this study using the measured well data.The influence characteristics of different observation system parameters on the resolution of specific deep-seated targets under the WFEM_E-Ex mode are analyzed in detail through forward modeling and inversion.Results show that the resolution ability of WFEM for deep,low-resistance thin layers is affected by factors such as transceiver distance,target layer thickness,and resistivity difference between the target body and the surrounding rock,but the influence range differs.This study analyzes the influence characteristics of various system parameters.It provides targeted work scheme design and feasibility analysis for deep shale gas exploration.It also offers an important theoretical basis for optimizing construction schemes and improving the recognition ability of WFEM for deep,low-resistance targets.
基金supported by Qingdao Key Medical and Health Discipline ProjectThe Intramural Research Program of the Affiliated Hospital of Qingdao University,No. 4910Qingdao West Coast New Area Science and Technology Project,No. 2020-55 (all to SW)。
文摘Border-associated macrophages are located at the interface between the brain and the periphery, including the perivascular spaces, choroid plexus, and meninges. Until recently, the functions of border-associated macrophages have been poorly understood and largely overlooked. However, a recent study reported that border-associated macrophages participate in stroke-induced inflammation, although many details and the underlying mechanisms remain unclear. In this study, we performed a comprehensive single-cell analysis of mouse border-associated macrophages using sequencing data obtained from the Gene Expression Omnibus(GEO) database(GSE174574 and GSE225948). Differentially expressed genes were identified, and enrichment analysis was performed to identify the transcription profile of border-associated macrophages. CellChat analysis was conducted to determine the cell communication network of border-associated macrophages. Transcription factors were predicted using the ‘pySCENIC' tool. We found that, in response to hypoxia, borderassociated macrophages underwent dynamic transcriptional changes and participated in the regulation of inflammatory-related pathways. Notably, the tumor necrosis factor pathway was activated by border-associated macrophages following ischemic stroke. The pySCENIC analysis indicated that the activity of signal transducer and activator of transcription 3(Stat3) was obviously upregulated in stroke, suggesting that Stat3 inhibition may be a promising strategy for treating border-associated macrophages-induced neuroinflammation. Finally, we constructed an animal model to investigate the effects of border-associated macrophages depletion following a stroke. Treatment with liposomes containing clodronate significantly reduced infarct volume in the animals and improved neurological scores compared with untreated animals. Taken together, our results demonstrate comprehensive changes in border-associated macrophages following a stroke, providing a theoretical basis for targeting border-associated macrophages-induced neuroinflammation in stroke treatment.
