In this investigation,a hybrid approach integrating the IDDES turbulence model and FW-H is employed to forecast the hydroacoustic of the rim driven thruster(RDT)under non-cavitation and uniform flow conditions at vary...In this investigation,a hybrid approach integrating the IDDES turbulence model and FW-H is employed to forecast the hydroacoustic of the rim driven thruster(RDT)under non-cavitation and uniform flow conditions at varying loading conditions(J=0.3 and J=0.6).It is revealed that the quadrupole term contribution in the P-FWH method significantly affects the monopole term in the low-frequency region,while it mainly affects the dipole term in the high-frequency region.Specifically,the overall sound pressure levels(SPL)of the RDT using the P-FWH method are 2.27 dB,10.03 dB,and 16.73 dB at the receiving points from R1 to R3 under the heavy-loaded condition,while they increase by 0.67 dB at R1,and decrease by 14.93 dB at R2,and 22.20 dB at R3,for the light-loaded condition.The study also utilizes the pressure-time derivatives to visualize the numerical noise and to pinpoint the dynamics of the vortex cores,and the optimization of the grid design can significantly reduce the numerical noise.The computational accuracy of the P-FWH method can meet the noise requirements for the preliminary design of rim driven thrusters.展开更多
Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On ...Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.展开更多
Under the combination of currents and waves, seabed scour occurs around offshore wind turbine foundations, which affects the stability and safe operation of offshore wind turbines. In this study, physical model experi...Under the combination of currents and waves, seabed scour occurs around offshore wind turbine foundations, which affects the stability and safe operation of offshore wind turbines. In this study, physical model experiments under unidirectional flow, bidirectional flow, and wave-current interactions with different flow directions around the pile group foundation were first conducted to investigate the development of scour around the pile group foundation.Additionally, a three-dimensional scour numerical model was established via the open-source software REEF3D to simulate the flow field and scour around the prototype-scale foundation. The impact of flow on scour was discussed.Under unidirectional flow, scour equilibrium was reached more quickly, with the maximum scour depth reaching approximately 1.2 times the pile diameter and the extent of the scour hole spanning about 4.9 times the pile diameter.Compared with those under unidirectional flow, the scour depths under combinations of currents and waves, as well as bidirectional flow, were slightly smaller. However, the morphology of scour holes was more uniform and symmetrical. The numerical simulation results show good agreement with the experimental data, demonstrating the impact of varying flow directions on the velocity distribution around the foundation, the morphology of scour holes, and the location of the maximum scour depth.展开更多
Numerical modelling is an effective technique to improve the understanding of outburst initiation mechanisms and to take appropriate measures to address their threats.Based on the existing two-way sequential coupling ...Numerical modelling is an effective technique to improve the understanding of outburst initiation mechanisms and to take appropriate measures to address their threats.Based on the existing two-way sequential coupling method,two typical types of outbursts,i.e.the gas pocket outburst and the dynamic fracturing outburst,have been successfully simulated using field data from a coalfield in central China.The geological structure commonly observed in the coalfield,known as the‘bedding shear zone’,contributes to the gas pocket outbursts in the region.The model for this type of outburst simulates mininginduced stress and gas pressure distributions during the outburst initiation stage and the subsequent development stage.Both coal ejection and gas release are observed in the model,and the simulation results are consistent with mine site observations,i.e.the amount of ejected coal,outburst cavity profile,and gas release rate change prior to an outburst.The second type of outburst is attributed to gas accumulation and elevated gas pressure due to the gassy floor seam and the heterogeneity in the floor strata,which is explained by the dynamic fracturing theory.While the dynamic coal ejection phenomenon is not captured in the simulation,the abrupt release of retained gas from a floor coal seam is successfully replicated.Both outburst models reveal that abnormal gas emission trends can be used as indicators of an upcoming outburst.The results of this study are expected to provide new insights into the outburst initiation mechanisms and outburst prevention measures.展开更多
Steel cylindrical shells are widely used in engineering structures due to their high strength-to-weight ratio,but they are vulnerable to buckling under axial loads.To address this limitation,fiber-reinforced polymer(F...Steel cylindrical shells are widely used in engineering structures due to their high strength-to-weight ratio,but they are vulnerable to buckling under axial loads.To address this limitation,fiber-reinforced polymer(FRP)composites have emerged as promising materials for structural reinforcement.This study investigates the buckling behavior of steel cylindrical shells reinforced with inner and outer layers of polymer composite materials under axial compression.Using analytical and numerical modeling methods,the critical buckling loads for different reinforcement options were evaluated.Two-sided glass fiber reinforced plastic(GFRP)or carbon fiber reinforced plastic(CFRP)coatings,as well as combined coatings with layers of different composites,were considered.GFRP+CFRPIn the calculations,the coatings were treated as homogeneous orthotropic materials with equivalent averaged elastic characteristics.The numerical analysis revealed that CFRP reinforcement achieved the highest increase in buckling load,with improvements ranging from 9.84%to 47.29%,depending on the composite thickness and steel shell thickness.GFRP reinforcement,while beneficial,demonstrated a lower effectiveness,with buckling load increases between 5.89%and 19.30%.The hybrid reinforcement provided an optimal balance,improving buckling resistance by GFRP+CFRP6.94%to 43.95%.Statistical analysis further identified composite type and thickness as the most significant factors affecting buckling performance.The findings suggest that CFRP is the preferred reinforcement material,especially when applied to thin-walled cylindrical shells,while hybrid reinforcements can be effectively utilized for structures requiring a balance between stiffness and ductility.These insights provide a foundation for optimizing FRP reinforcement strategies to enhance the structural integrity of steel shells in engineering applications.展开更多
With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ...With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ventilation pipes of different structures are investigated by experiments and numerical simulations.Furthermore,for the same structure,the effects of peak pressure and positive pressure time on the attenuation rate are discussed.It is found that the attenuation rate increases with the incident shock wave pressure,and the shock wave attenuation rate tends to reach its limiting value k for the same structure and reasonably short positive pressure time.Under the same conditions,the attenuation rate is calculated using the pressure of the shock wave as follows:diffusion chamber pipe,branch pipe and selfconsumption pipe;the attenuation rate per unit volume is calculated as follows:self-consumption pipe,branch pipe and diffusion chamber pipe.In addition,an easy method is provided to calculate the attenuation rate of the shock wave in single and multi-stage ventilation pipes.Corresponding parameters are provided for various structures,and the margin of error between the formulae and experimental results is within 10%,which is significant for engineering applications.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
The impact force effect on launch platform motion response represents a critical safety consideration that requires thorough investigation prior to sea-launch implementation. This paper examines a self-designed semi-s...The impact force effect on launch platform motion response represents a critical safety consideration that requires thorough investigation prior to sea-launch implementation. This paper examines a self-designed semi-submersible launch platform comprising a box-shaped deck, six columns, and two pontoons, with sufficient structural stiffness to be analyzed as a rigid body. A proprietary code based on three-dimensional linear potential theory was developed for hydrodynamic analysis of the launching process. The Cummins equation was implemented to calculate platform responses under substantial impact force. The numerical results were validated through comparison with ANSYS/Aqwa commercial software for platform motion response in both launch and non-launch cases. Additionally, two model tests were conducted in a sea-keeping wave basin at a scale ratio of λ =1:40. The numerical results demonstrated good agreement with experimental data. Both numerical and experimental findings indicate that platform motion responses result from wave-induced effects and impact force/rocket weight effects, with the latter typically predominant. Numerical simulations revealed that in moderate sea states, maximum heave and pitch motions measure 0.6 m and 1°, respectively, suggesting the viability of sea-launch operations using the designed platform under these conditions.展开更多
Hypersonic magnetohydrodynamic(MHD)control effectively enhances the aerothermal environment of aerospace vehicles,demonstrating considerable potential in plasma flow regulation and aerodynamic optimiza-tion.As aerospa...Hypersonic magnetohydrodynamic(MHD)control effectively enhances the aerothermal environment of aerospace vehicles,demonstrating considerable potential in plasma flow regulation and aerodynamic optimiza-tion.As aerospace vehicles progress toward mid-low-altitude hypersonic regimes,their external aerothermal conditions become increasingly severe.This study addresses the challenges of complex aerodynamic force/heat environments and the difficulties in MHD control numerical simulations for hypersonic vehicles at mid-low al-titudes.On the basis of the perfect gas model and the low magnetic Reynolds number assumption,we conduct numerical simulations of MHD control under mid-low altitudes,high-Mach-number conditions.The findings reveal the following:(1)the low magnetic Reynolds number assumption is valid and computationally accurate,as corroborated by a comparative analysis with the literature;(2)in the mid-low altitude hypersonic regime,magnetic fields significantly suppress the shock standoffdistance and reduce the surface heat flux.Both the mag-netically controlled shock wave and the thermal protection exhibit nonlinear variations with the Mach number,increasing and then decreasing as the Mach number increases.The optimal Mach number for shock wave control is 13,whereas optimal thermal protection is achieved at Mach 15.At an altitude of 40 km,the optimal magne-tohydrodynamic Mach range spans 13-17,achieving a maximum heat flux attenuation of 28.81%.Additionally,the effects of magnetic shock wave control correlate approximately exponentially with altitude within certain parameters,whereas the efficacy of thermal protection behaves linearly with altitude variations.展开更多
It has been experimentally observed that,in the perforation of metal plates by a flat-nosed projectile,there exists a plateau phenomenon where the ballistic limit increases slightly with increasing plate thickness,whi...It has been experimentally observed that,in the perforation of metal plates by a flat-nosed projectile,there exists a plateau phenomenon where the ballistic limit increases slightly with increasing plate thickness,which is related to a change in the mode of failure.No theoretical model has so far explained this phenomenon satisfactorily.This paper presents a combined numerical and theoretical study on the perforation of 2024-T351 aluminum plates struck by flat-nosed projectiles.First,numerical simulations are performed to investigate the failure mechanisms/deformation modes of the aluminum plates.Then,a theoretical model is proposed based on the numerical results and the experimental observations within a unified framework.The model takes into account the main energy absorbing mechanisms and the corresponding energies absorbed are determined analytically.In particular,a dimensionless equation is suggested to describe the relationship between global deformations and impact velocity.It transpires that the model predictions are in good agreement with the test data and the numerical results for the perforation of 2024-T351 aluminum plates struck by rigid flat-nosed projectiles in terms of residual velocity,ballistic limit,relationship between global deformations and impact velocity,and transition of failure modes.It also transpires that the present model can predict the“plateau”phenomenon,which shows a slight increase in ballistic limit as plate thickness increases.Furthermore,the energy absorption mechanisms are discussed on the basis of the theoretical analysis.展开更多
Granular bed filter is one of the most promising technologies for the dust removal from high temperature coal pyrolysis gas.In this work,three-dimensional numerical models were employed to investigate the influence of...Granular bed filter is one of the most promising technologies for the dust removal from high temperature coal pyrolysis gas.In this work,three-dimensional numerical models were employed to investigate the influence of operation parameters on collection efficiency,especially paying attention to particle deposition characteristics in the bed and outlet particle size distribution.The results show that the operation parameters have different effects on the collection efficiency of particles with the different properties.Under the same conditions,the collection efficiency of granular bed for circulating ash increases more rapidly compared to that of char particles.According to the effective Stokes number(N_(steff)),the collection efficiency of granular bed can be obviously divided into three regions:difficult separation region(N_(steff)≤0.25),transition region(0.25<N_(steff)<0.83)and easy separation region(N_(steff)≥0.83).Dust deposition within the bed exhibits axial attenuation along the gas flow direction,allowing classification of deposited particles into two characteristic types:dispersed particles and congregated particles.In addition,granular bed filtration induces a morphological transition of particle size distribution,transforming the original monomodal profile into a well-defined bimodal structure.A correlation formula of the collection efficiency was developed,providing critical insights for the engineering design of granular bed filters.展开更多
As a renewable energy source,the thermal conversion of poultry manure,is a promising waste treatment solution that can generate circular economic outputs such as energy and reduce greenhouse gas emissions.Currently,pr...As a renewable energy source,the thermal conversion of poultry manure,is a promising waste treatment solution that can generate circular economic outputs such as energy and reduce greenhouse gas emissions.Currently,pressurized gasification of poultry manure is still a novel research field,especially when combined with a novel technological route of oxy-fuel gasification.Oxy-fuel gasification is a newly proposed and promising gasification technology for power generation that facilitates future carbon capture and storage.In this work,based on a commercially operated industrial-scale chicken manure gasification power plant in Singapore,we presented an interesting first exploration of the coupled pressurization technology for oxy-fuel gasification of poultry manure using CFD numerical simulation,analyzed the effects of pressure and oxygen enrichment concentration as well as the coupling mechanism between them,and discussed the conversion and emission of nitrogen-and sulfur-containing pollutants.The results indicate that under oxy-fuel gasification condition(Oxy-30,i.e.,30%O_(2)/70%CO_(2)),as the pressure increases from 0.1 to 0.5 MPa,the CO concentration in the syngas increases slightly,the H_(2)concentration increases to approximately 25%,and the CH4 concentration(less than 1%)decreases,resulting in an increase in the calorific value of syngas from 5.2 to 5.6 MJ·m^(-3).Compared to atmospheric pressure conditions,a relatively higher oxygen-enriched concentration interval(Oxy-40 to Oxy-50)under pressurized conditions is advantageous for autothermal gasification.Pressurization increases NO precursors production and also promotes homogeneous and heterogeneous reduction of NO,and provides favorable conditions for self-desulfurization.This work offers reference for the realization of a highly efficient and low-energy-consumption thermochemical treatment of livestock manure coupled with negative carbon emission technology.展开更多
Most of the existing studies on tunnel blast wave are based on spherical or grouped charges, however,conventional weapons are mostly cylindrical rather than spherical. In order to analyze the impact of cylindrical cha...Most of the existing studies on tunnel blast wave are based on spherical or grouped charges, however,conventional weapons are mostly cylindrical rather than spherical. In order to analyze the impact of cylindrical charges on the tunnel blast wave loads and to develop a quantitative calculation method, this study carried out experimental and numerical research. Initially, external explosion experiments were conducted using both 35 kg spherical charges and cylindrical charges with aspect ratio of 4.8 at two different distances from the tunnel entrance. Comparative analysis of the blast wave parameters in the tunnel revealed that the explosive equivalent of the cylindrical charges was significantly higher than that of the spherical charges. To address this, an equivalent coefficient κ based on the spherical charges was proposed for the cylindrical charges. Subsequently, numerical simulations were conducted for the experimental conditions, and the numerical simulation results match the experiments well. Through numerical calculations, the reliability of the equivalent coefficient κ under the experimental conditions was verified, and comparison analysis indicated that the explosion energy of cylindrical charges spreads more radially, resulting in more explosion energy entering the tunnel, which is the fundamental reason for the increase in tunnel blast wave loads. Additionally, analyzing the explosion energy ratio entering the tunnel is an effective method for calculating the equivalent coefficient κ. Finally, through more than one hundred sets of numerical calculation results, the impact of the proportional distance λ and the ratio of charge mass to the tunnel cross-section dimension φ on the equivalence coefficients κ was investigated. An empirical formula for the equivalence coefficient κ was derived through fitting, and the accuracy of the formula was validated through literature experimental results. The research findings of this paper will provide valuable guidance for the calculation of blast wave loads in tunnel.展开更多
Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer...Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer solutions exhibit non-Newtonian and nonlinear flow behavior including shear thinning and shear thickening,polymer convection,diffusion,adsorption,retention,inaccessible pore volume,and reduced effective permeability.However,available well test model of polymer flooding wells generally simplifies these characteristics on pressure transient response,which may lead to inaccurate results.This work proposes a novel two-phase numerical well test model to better describe the polymer viscoelasticity and nonlinear flow behavior.Different influence factors that related to near-well blockage during polymer flooding process,including the degree of blockage(inner zone permeability),the extent of blockage(composite radius),and polymer flooding front radius are explored to investigate these impacts on bottom hole pressure responses.Results show that polymer viscoelasticity has a significant impact on the transitional flow segment of type curves,and the effects of near-well formation blockage and polymer concentration distribution on well test curves are very similar.Thus,to accurately interpret the degree of near-well blockage in injection wells,it is essential to first eliminate the influence of polymer viscoelasticity.Finally,a field case is comprehensively analyzed and discussed to illustrate the applicability of the proposed model.展开更多
The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combi...The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combines numerical simulation with machine learning techniques to explore this issue.It presents a summary of special-shaped tunnel geometries and introduces a shape coefficient.Through the finite element software,Plaxis3D,the study simulates six key parameters—shape coefficient,burial depth ratio,tunnel’s longest horizontal length,internal friction angle,cohesion,and soil submerged bulk density—that impact uplift resistance across different conditions.Employing XGBoost and ANN methods,the feature importance of each parameter was analyzed based on the numerical simulation results.The findings demonstrate that a tunnel shape more closely resembling a circle leads to reduced uplift resistance in the overlying soil,whereas other parameters exhibit the contrary effects.Furthermore,the study reveals a diminishing trend in the feature importance of buried depth ratio,internal friction angle,tunnel longest horizontal length,cohesion,soil submerged bulk density,and shape coefficient in influencing uplift resistance.展开更多
Swells are critical concerns regarding safety,marine transportation,and coastal engineering construction of coastal countries along the Gulf of Guinea and have been scientific problems due to the lack of systematic th...Swells are critical concerns regarding safety,marine transportation,and coastal engineering construction of coastal countries along the Gulf of Guinea and have been scientific problems due to the lack of systematic theoretical,numerical,and observational research.In this study,a double nesting numerical model was constructed and validated from the Atlantic Ocean to the Gulf of Guinea based on simulating waves nearshore(SWAN)to explore the swell characteristics and source tracing in the Gulf of Guinea in winter and summer seasons from 2020 to 2021.Simulation results reveal that swells are stronger and deflect more to the west in winter than summer,even though they dominate in both seasons in the Gulf of Guinea in the S-SW directional range.Simulated two-dimensional(2D)wave spectral patterns not only clarify wave composition,variation,and propagation properties from the central South Atlantic Ocean to the Gulf of Guinea,but also distinguish swell strength and directional range in winter and summer.The NW wind events induce swells which spread toward the SSE-ESE direction from the North Atlantic Ocean,big wind source generates sustained and stable S-SW swells from the South Atlantic Ocean,and corresponding swell-influenced areas are discussed.The strongest swell event in the Gulf of Guinea during the simulation was used as a case study to trace its source.A strong clockwise wind vortex within the Roaring Forties induced these large swells in the Gulf of Guinea approximately 5.5 days later,and swell propagation formed a regular isoline of peak period distribution from the South Atlantic Ocean to the Gulf of Guinea in the SSW-SW direction.展开更多
Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing addit...Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.展开更多
This paper presents a comprehensive experimental and numerical investigation of radiant floor heating(RFH)systems integrated with phase changematerial(PCM)-based thermal energy storage(TES).The study compares two unde...This paper presents a comprehensive experimental and numerical investigation of radiant floor heating(RFH)systems integrated with phase changematerial(PCM)-based thermal energy storage(TES).The study compares two underfloor pipe configurations:double serpentine and spiral.It also looks at how well a paraffin wax PCM system works with compact heat exchanger-type TES units during winter in Iraq.Key performance indicators including discharge temperature,heat transfer rate,liquid fraction evolution,and temperature uniformity were assessed through in situ experimental measurements and ANSYS fluent simulations.Results demonstrate that the spiral design provides slightly more uniform temperature distribution on the tile surface at an inlet water temperature of 55℃,with an average difference of approximately 0.5%,the serpentine layout exhibits higher slab temperature distribution by about 0.66%.Notably,the serpentine configuration shows superior thermal homogeneity and heat distribution,with a 15.05%increase in heat gain at a 55℃ inlet temperature compared to the spiral design.The performance gap between the two layouts narrows as the inlet temperature increases from 50℃ in 5℃ increments by approximately 4.1%,3.7%,and 1.7%,respectively.Higher inlet temperatures also improve PCM discharging and charging rates,improving energy storage utilization.The findings provide significant design guidelines for sustainable heating systems for cold climates.展开更多
Objective:To identify the root causes of typical adverse drug events through the lens of patient experiences proposing novel strategies to mitigate preventable harm.Methods:A qualitative case study leveraging in-depth...Objective:To identify the root causes of typical adverse drug events through the lens of patient experiences proposing novel strategies to mitigate preventable harm.Methods:A qualitative case study leveraging in-depth interviews with patients and families,anchored by Interactive Patient Par ticipation Theory,to analyze 4 high-severity adverse drug events(ADE)cases.Cases were purposively sampled from 8 communities in China's National Adverse Event Monitor Center(2018-2023).Semi-structured interviews explored patient perspectives,with data analyzed via thematic coding and triangulation against clinical records.Results:Five interconnected themes emerged:(1)erosion of trust,(2)communication breakdowns,(3)information asymmetry,(4)environmental inadequacies,and(5)technological alienation.Notably,75% of participants had≤high school education,and 50% used≥7 medications daily,compounding ADE risks.Conclusions:We considered elements mentioned by theory,exploring trust,communication,information,and suppor t as the root causes.In addition,we added“adaptability to new technology”as an impor tant and necessary component.It is impor tant and necessary to analyze typical adverse drug events from the perspectives of patients.展开更多
Mindfulness would enhance university students’emotional well-being and study engagement.However,the role of affect(positive and negative emotions)and psychological resources(psychological capital)linking mindfulness ...Mindfulness would enhance university students’emotional well-being and study engagement.However,the role of affect(positive and negative emotions)and psychological resources(psychological capital)linking mindfulness to study engagement remain underexplored.This cross-sectional study surveyed 688 Chinese university students(females=413,mean age=20.3,SD=0.83),using validated self-report measures of mindfulness,positive and negative emotions,psychological capital,and study engagement.Structural equation modeling and bias-corrected bootstrap analyses(5000 resamples)revealed that mindfulness directly enhanced positive emotions,psychological capital,and study engagement,while reducing negative emotions.Positive emotions partially mediated the positive effect of mindfulness on psychological capital and study engagement.Negative emotions partially and negatively mediated only the mindfulness-psychological capital link.Psychological capital independently mediated the mindfulness-engagement relationship,and two sequential mediation pathways emerged:(a)mindfulness→positive emotions→psychological capital→higher study engagement and(b)mindfulness→reduced negative emotions→psychological capital→higher study engagement.Consistent with broaden-and-build(B&B)theory and Conservation of Resources(COR)theory,these findings suggest that mindfulness fosters study engagement primarily by promoting positive emotional experiences and strengthening psychological capital.By implication,university student support programs should employ mindfulness-based interventions to cultivate emotional and psychological resources for higher students’engagement and overall well-being.展开更多
基金The National Natural Science Foundation of China(Grant No.52201376)the Natural Science Foundation of Hubei Province,China(Grant No.2023AFB683).
文摘In this investigation,a hybrid approach integrating the IDDES turbulence model and FW-H is employed to forecast the hydroacoustic of the rim driven thruster(RDT)under non-cavitation and uniform flow conditions at varying loading conditions(J=0.3 and J=0.6).It is revealed that the quadrupole term contribution in the P-FWH method significantly affects the monopole term in the low-frequency region,while it mainly affects the dipole term in the high-frequency region.Specifically,the overall sound pressure levels(SPL)of the RDT using the P-FWH method are 2.27 dB,10.03 dB,and 16.73 dB at the receiving points from R1 to R3 under the heavy-loaded condition,while they increase by 0.67 dB at R1,and decrease by 14.93 dB at R2,and 22.20 dB at R3,for the light-loaded condition.The study also utilizes the pressure-time derivatives to visualize the numerical noise and to pinpoint the dynamics of the vortex cores,and the optimization of the grid design can significantly reduce the numerical noise.The computational accuracy of the P-FWH method can meet the noise requirements for the preliminary design of rim driven thrusters.
文摘Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.
基金financially supported by the National Key Research and Development Program of China (Grant No. 2021YFB2601100)the National Natural Science Foundation of China (Grant No. 51979190)。
文摘Under the combination of currents and waves, seabed scour occurs around offshore wind turbine foundations, which affects the stability and safe operation of offshore wind turbines. In this study, physical model experiments under unidirectional flow, bidirectional flow, and wave-current interactions with different flow directions around the pile group foundation were first conducted to investigate the development of scour around the pile group foundation.Additionally, a three-dimensional scour numerical model was established via the open-source software REEF3D to simulate the flow field and scour around the prototype-scale foundation. The impact of flow on scour was discussed.Under unidirectional flow, scour equilibrium was reached more quickly, with the maximum scour depth reaching approximately 1.2 times the pile diameter and the extent of the scour hole spanning about 4.9 times the pile diameter.Compared with those under unidirectional flow, the scour depths under combinations of currents and waves, as well as bidirectional flow, were slightly smaller. However, the morphology of scour holes was more uniform and symmetrical. The numerical simulation results show good agreement with the experimental data, demonstrating the impact of varying flow directions on the velocity distribution around the foundation, the morphology of scour holes, and the location of the maximum scour depth.
基金the National Natural Science Foundation of China(52304105)National Natural Science Foundation of China-National major scientific research instrument development project(52227901)Jiangsu Province International Collaboration Program-Key national industrial technology research and development cooperation projects(BZ2023050).
文摘Numerical modelling is an effective technique to improve the understanding of outburst initiation mechanisms and to take appropriate measures to address their threats.Based on the existing two-way sequential coupling method,two typical types of outbursts,i.e.the gas pocket outburst and the dynamic fracturing outburst,have been successfully simulated using field data from a coalfield in central China.The geological structure commonly observed in the coalfield,known as the‘bedding shear zone’,contributes to the gas pocket outbursts in the region.The model for this type of outburst simulates mininginduced stress and gas pressure distributions during the outburst initiation stage and the subsequent development stage.Both coal ejection and gas release are observed in the model,and the simulation results are consistent with mine site observations,i.e.the amount of ejected coal,outburst cavity profile,and gas release rate change prior to an outburst.The second type of outburst is attributed to gas accumulation and elevated gas pressure due to the gassy floor seam and the heterogeneity in the floor strata,which is explained by the dynamic fracturing theory.While the dynamic coal ejection phenomenon is not captured in the simulation,the abrupt release of retained gas from a floor coal seam is successfully replicated.Both outburst models reveal that abnormal gas emission trends can be used as indicators of an upcoming outburst.The results of this study are expected to provide new insights into the outburst initiation mechanisms and outburst prevention measures.
文摘Steel cylindrical shells are widely used in engineering structures due to their high strength-to-weight ratio,but they are vulnerable to buckling under axial loads.To address this limitation,fiber-reinforced polymer(FRP)composites have emerged as promising materials for structural reinforcement.This study investigates the buckling behavior of steel cylindrical shells reinforced with inner and outer layers of polymer composite materials under axial compression.Using analytical and numerical modeling methods,the critical buckling loads for different reinforcement options were evaluated.Two-sided glass fiber reinforced plastic(GFRP)or carbon fiber reinforced plastic(CFRP)coatings,as well as combined coatings with layers of different composites,were considered.GFRP+CFRPIn the calculations,the coatings were treated as homogeneous orthotropic materials with equivalent averaged elastic characteristics.The numerical analysis revealed that CFRP reinforcement achieved the highest increase in buckling load,with improvements ranging from 9.84%to 47.29%,depending on the composite thickness and steel shell thickness.GFRP reinforcement,while beneficial,demonstrated a lower effectiveness,with buckling load increases between 5.89%and 19.30%.The hybrid reinforcement provided an optimal balance,improving buckling resistance by GFRP+CFRP6.94%to 43.95%.Statistical analysis further identified composite type and thickness as the most significant factors affecting buckling performance.The findings suggest that CFRP is the preferred reinforcement material,especially when applied to thin-walled cylindrical shells,while hybrid reinforcements can be effectively utilized for structures requiring a balance between stiffness and ductility.These insights provide a foundation for optimizing FRP reinforcement strategies to enhance the structural integrity of steel shells in engineering applications.
文摘With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ventilation pipes of different structures are investigated by experiments and numerical simulations.Furthermore,for the same structure,the effects of peak pressure and positive pressure time on the attenuation rate are discussed.It is found that the attenuation rate increases with the incident shock wave pressure,and the shock wave attenuation rate tends to reach its limiting value k for the same structure and reasonably short positive pressure time.Under the same conditions,the attenuation rate is calculated using the pressure of the shock wave as follows:diffusion chamber pipe,branch pipe and selfconsumption pipe;the attenuation rate per unit volume is calculated as follows:self-consumption pipe,branch pipe and diffusion chamber pipe.In addition,an easy method is provided to calculate the attenuation rate of the shock wave in single and multi-stage ventilation pipes.Corresponding parameters are provided for various structures,and the margin of error between the formulae and experimental results is within 10%,which is significant for engineering applications.
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financially supported by the National Natural Science Foundation of China (Grant No.52401346)the Natural Science Foundation of Jiangsu Province of China (Grant No.BK20230183)the Taihu Lake Talent Plan of Wuxi。
文摘The impact force effect on launch platform motion response represents a critical safety consideration that requires thorough investigation prior to sea-launch implementation. This paper examines a self-designed semi-submersible launch platform comprising a box-shaped deck, six columns, and two pontoons, with sufficient structural stiffness to be analyzed as a rigid body. A proprietary code based on three-dimensional linear potential theory was developed for hydrodynamic analysis of the launching process. The Cummins equation was implemented to calculate platform responses under substantial impact force. The numerical results were validated through comparison with ANSYS/Aqwa commercial software for platform motion response in both launch and non-launch cases. Additionally, two model tests were conducted in a sea-keeping wave basin at a scale ratio of λ =1:40. The numerical results demonstrated good agreement with experimental data. Both numerical and experimental findings indicate that platform motion responses result from wave-induced effects and impact force/rocket weight effects, with the latter typically predominant. Numerical simulations revealed that in moderate sea states, maximum heave and pitch motions measure 0.6 m and 1°, respectively, suggesting the viability of sea-launch operations using the designed platform under these conditions.
基金the results of the research project funded by National Numerical Wind Tunnel Project of China.
文摘Hypersonic magnetohydrodynamic(MHD)control effectively enhances the aerothermal environment of aerospace vehicles,demonstrating considerable potential in plasma flow regulation and aerodynamic optimiza-tion.As aerospace vehicles progress toward mid-low-altitude hypersonic regimes,their external aerothermal conditions become increasingly severe.This study addresses the challenges of complex aerodynamic force/heat environments and the difficulties in MHD control numerical simulations for hypersonic vehicles at mid-low al-titudes.On the basis of the perfect gas model and the low magnetic Reynolds number assumption,we conduct numerical simulations of MHD control under mid-low altitudes,high-Mach-number conditions.The findings reveal the following:(1)the low magnetic Reynolds number assumption is valid and computationally accurate,as corroborated by a comparative analysis with the literature;(2)in the mid-low altitude hypersonic regime,magnetic fields significantly suppress the shock standoffdistance and reduce the surface heat flux.Both the mag-netically controlled shock wave and the thermal protection exhibit nonlinear variations with the Mach number,increasing and then decreasing as the Mach number increases.The optimal Mach number for shock wave control is 13,whereas optimal thermal protection is achieved at Mach 15.At an altitude of 40 km,the optimal magne-tohydrodynamic Mach range spans 13-17,achieving a maximum heat flux attenuation of 28.81%.Additionally,the effects of magnetic shock wave control correlate approximately exponentially with altitude within certain parameters,whereas the efficacy of thermal protection behaves linearly with altitude variations.
文摘It has been experimentally observed that,in the perforation of metal plates by a flat-nosed projectile,there exists a plateau phenomenon where the ballistic limit increases slightly with increasing plate thickness,which is related to a change in the mode of failure.No theoretical model has so far explained this phenomenon satisfactorily.This paper presents a combined numerical and theoretical study on the perforation of 2024-T351 aluminum plates struck by flat-nosed projectiles.First,numerical simulations are performed to investigate the failure mechanisms/deformation modes of the aluminum plates.Then,a theoretical model is proposed based on the numerical results and the experimental observations within a unified framework.The model takes into account the main energy absorbing mechanisms and the corresponding energies absorbed are determined analytically.In particular,a dimensionless equation is suggested to describe the relationship between global deformations and impact velocity.It transpires that the model predictions are in good agreement with the test data and the numerical results for the perforation of 2024-T351 aluminum plates struck by rigid flat-nosed projectiles in terms of residual velocity,ballistic limit,relationship between global deformations and impact velocity,and transition of failure modes.It also transpires that the present model can predict the“plateau”phenomenon,which shows a slight increase in ballistic limit as plate thickness increases.Furthermore,the energy absorption mechanisms are discussed on the basis of the theoretical analysis.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA29020400)the National Key Research and Development Program of China(2018YFB0605003)financial support from the Science and Technology Program of Yan'an(2023SLGYGG-001)。
文摘Granular bed filter is one of the most promising technologies for the dust removal from high temperature coal pyrolysis gas.In this work,three-dimensional numerical models were employed to investigate the influence of operation parameters on collection efficiency,especially paying attention to particle deposition characteristics in the bed and outlet particle size distribution.The results show that the operation parameters have different effects on the collection efficiency of particles with the different properties.Under the same conditions,the collection efficiency of granular bed for circulating ash increases more rapidly compared to that of char particles.According to the effective Stokes number(N_(steff)),the collection efficiency of granular bed can be obviously divided into three regions:difficult separation region(N_(steff)≤0.25),transition region(0.25<N_(steff)<0.83)and easy separation region(N_(steff)≥0.83).Dust deposition within the bed exhibits axial attenuation along the gas flow direction,allowing classification of deposited particles into two characteristic types:dispersed particles and congregated particles.In addition,granular bed filtration induces a morphological transition of particle size distribution,transforming the original monomodal profile into a well-defined bimodal structure.A correlation formula of the collection efficiency was developed,providing critical insights for the engineering design of granular bed filters.
基金supported by the National Natural Science Foundation of China(52306131)the Natural Science Foundation of Jiangsu Province(BK20230847)+2 种基金the Key Project of the National Natural Science Foundation of China(52336005)the Fundamental Research Funds for the Central Universities(2242024RCB0036)the Open Project Program of State Key Laboratory of Low-carbon Smart Coal-fired Power Generation and Ultra-clean Emission(D2024FK156).
文摘As a renewable energy source,the thermal conversion of poultry manure,is a promising waste treatment solution that can generate circular economic outputs such as energy and reduce greenhouse gas emissions.Currently,pressurized gasification of poultry manure is still a novel research field,especially when combined with a novel technological route of oxy-fuel gasification.Oxy-fuel gasification is a newly proposed and promising gasification technology for power generation that facilitates future carbon capture and storage.In this work,based on a commercially operated industrial-scale chicken manure gasification power plant in Singapore,we presented an interesting first exploration of the coupled pressurization technology for oxy-fuel gasification of poultry manure using CFD numerical simulation,analyzed the effects of pressure and oxygen enrichment concentration as well as the coupling mechanism between them,and discussed the conversion and emission of nitrogen-and sulfur-containing pollutants.The results indicate that under oxy-fuel gasification condition(Oxy-30,i.e.,30%O_(2)/70%CO_(2)),as the pressure increases from 0.1 to 0.5 MPa,the CO concentration in the syngas increases slightly,the H_(2)concentration increases to approximately 25%,and the CH4 concentration(less than 1%)decreases,resulting in an increase in the calorific value of syngas from 5.2 to 5.6 MJ·m^(-3).Compared to atmospheric pressure conditions,a relatively higher oxygen-enriched concentration interval(Oxy-40 to Oxy-50)under pressurized conditions is advantageous for autothermal gasification.Pressurization increases NO precursors production and also promotes homogeneous and heterogeneous reduction of NO,and provides favorable conditions for self-desulfurization.This work offers reference for the realization of a highly efficient and low-energy-consumption thermochemical treatment of livestock manure coupled with negative carbon emission technology.
文摘Most of the existing studies on tunnel blast wave are based on spherical or grouped charges, however,conventional weapons are mostly cylindrical rather than spherical. In order to analyze the impact of cylindrical charges on the tunnel blast wave loads and to develop a quantitative calculation method, this study carried out experimental and numerical research. Initially, external explosion experiments were conducted using both 35 kg spherical charges and cylindrical charges with aspect ratio of 4.8 at two different distances from the tunnel entrance. Comparative analysis of the blast wave parameters in the tunnel revealed that the explosive equivalent of the cylindrical charges was significantly higher than that of the spherical charges. To address this, an equivalent coefficient κ based on the spherical charges was proposed for the cylindrical charges. Subsequently, numerical simulations were conducted for the experimental conditions, and the numerical simulation results match the experiments well. Through numerical calculations, the reliability of the equivalent coefficient κ under the experimental conditions was verified, and comparison analysis indicated that the explosion energy of cylindrical charges spreads more radially, resulting in more explosion energy entering the tunnel, which is the fundamental reason for the increase in tunnel blast wave loads. Additionally, analyzing the explosion energy ratio entering the tunnel is an effective method for calculating the equivalent coefficient κ. Finally, through more than one hundred sets of numerical calculation results, the impact of the proportional distance λ and the ratio of charge mass to the tunnel cross-section dimension φ on the equivalence coefficients κ was investigated. An empirical formula for the equivalence coefficient κ was derived through fitting, and the accuracy of the formula was validated through literature experimental results. The research findings of this paper will provide valuable guidance for the calculation of blast wave loads in tunnel.
基金supported by the National Natural Science Foundation of China(52104049)the Young Elite Scientist Sponsorship Program by Beijing Association for Science and Technology(BYESS2023262)。
文摘Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer solutions exhibit non-Newtonian and nonlinear flow behavior including shear thinning and shear thickening,polymer convection,diffusion,adsorption,retention,inaccessible pore volume,and reduced effective permeability.However,available well test model of polymer flooding wells generally simplifies these characteristics on pressure transient response,which may lead to inaccurate results.This work proposes a novel two-phase numerical well test model to better describe the polymer viscoelasticity and nonlinear flow behavior.Different influence factors that related to near-well blockage during polymer flooding process,including the degree of blockage(inner zone permeability),the extent of blockage(composite radius),and polymer flooding front radius are explored to investigate these impacts on bottom hole pressure responses.Results show that polymer viscoelasticity has a significant impact on the transitional flow segment of type curves,and the effects of near-well formation blockage and polymer concentration distribution on well test curves are very similar.Thus,to accurately interpret the degree of near-well blockage in injection wells,it is essential to first eliminate the influence of polymer viscoelasticity.Finally,a field case is comprehensively analyzed and discussed to illustrate the applicability of the proposed model.
基金Guangzhou Metro Scientific Research Project(No.JT204-100111-23001)Chongqing Municipal Special Project for Technological Innovation and Application Development(No.CSTB2022TIAD-KPX0101)Science and Technology Research and Development Program of China State Railway Group Co.,Ltd.(No.N2023G045)。
文摘The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combines numerical simulation with machine learning techniques to explore this issue.It presents a summary of special-shaped tunnel geometries and introduces a shape coefficient.Through the finite element software,Plaxis3D,the study simulates six key parameters—shape coefficient,burial depth ratio,tunnel’s longest horizontal length,internal friction angle,cohesion,and soil submerged bulk density—that impact uplift resistance across different conditions.Employing XGBoost and ANN methods,the feature importance of each parameter was analyzed based on the numerical simulation results.The findings demonstrate that a tunnel shape more closely resembling a circle leads to reduced uplift resistance in the overlying soil,whereas other parameters exhibit the contrary effects.Furthermore,the study reveals a diminishing trend in the feature importance of buried depth ratio,internal friction angle,tunnel longest horizontal length,cohesion,soil submerged bulk density,and shape coefficient in influencing uplift resistance.
基金The National Key R&D Program of China under contract No.2023YFE0126300the National Natural Science Foundation of China under contract Nos 42066002 and U20A2099.
文摘Swells are critical concerns regarding safety,marine transportation,and coastal engineering construction of coastal countries along the Gulf of Guinea and have been scientific problems due to the lack of systematic theoretical,numerical,and observational research.In this study,a double nesting numerical model was constructed and validated from the Atlantic Ocean to the Gulf of Guinea based on simulating waves nearshore(SWAN)to explore the swell characteristics and source tracing in the Gulf of Guinea in winter and summer seasons from 2020 to 2021.Simulation results reveal that swells are stronger and deflect more to the west in winter than summer,even though they dominate in both seasons in the Gulf of Guinea in the S-SW directional range.Simulated two-dimensional(2D)wave spectral patterns not only clarify wave composition,variation,and propagation properties from the central South Atlantic Ocean to the Gulf of Guinea,but also distinguish swell strength and directional range in winter and summer.The NW wind events induce swells which spread toward the SSE-ESE direction from the North Atlantic Ocean,big wind source generates sustained and stable S-SW swells from the South Atlantic Ocean,and corresponding swell-influenced areas are discussed.The strongest swell event in the Gulf of Guinea during the simulation was used as a case study to trace its source.A strong clockwise wind vortex within the Roaring Forties induced these large swells in the Gulf of Guinea approximately 5.5 days later,and swell propagation formed a regular isoline of peak period distribution from the South Atlantic Ocean to the Gulf of Guinea in the SSW-SW direction.
基金National Key Research and Development Program of China(2022YFB4600902)Shandong Provincial Science Foundation for Outstanding Young Scholars(ZR2024YQ020)。
文摘Wire arc additive manufacturing(WAAM)has emerged as a promising approach for fabricating large-scale components.However,conventional WAAM still faces challenges in optimizing microstructural evolution,minimizing additive-induced defects,and alleviating residual stress and deformation,all of which are critical for enhancing the mechanical performance of the manufactured parts.Integrating interlayer friction stir processing(FSP)into WAAM significantly enhances the quality of deposited materials.However,numerical simulation research focusing on elucidating the associated thermomechanical coupling mechanisms remains insufficient.A comprehensive numerical model was developed to simulate the thermomechanical coupling behavior in friction stir-assisted WAAM.The influence of post-deposition FSP on the coupled thermomechanical response of the WAAM process was analyzed quantitatively.Moreover,the residual stress distribution and deformation behavior under both single-layer and multilayer deposition conditions were investigated.Thermal analysis of different deposition layers in WAAM and friction stir-assisted WAAM was conducted.Results show that subsequent layer deposition induces partial remelting of the previously solidified layer,whereas FSP does not cause such remelting.Furthermore,thermal stress and deformation analysis confirm that interlayer FSP effectively mitigates residual stresses and distortion in WAAM components,thereby improving their structural integrity and mechanical properties.
文摘This paper presents a comprehensive experimental and numerical investigation of radiant floor heating(RFH)systems integrated with phase changematerial(PCM)-based thermal energy storage(TES).The study compares two underfloor pipe configurations:double serpentine and spiral.It also looks at how well a paraffin wax PCM system works with compact heat exchanger-type TES units during winter in Iraq.Key performance indicators including discharge temperature,heat transfer rate,liquid fraction evolution,and temperature uniformity were assessed through in situ experimental measurements and ANSYS fluent simulations.Results demonstrate that the spiral design provides slightly more uniform temperature distribution on the tile surface at an inlet water temperature of 55℃,with an average difference of approximately 0.5%,the serpentine layout exhibits higher slab temperature distribution by about 0.66%.Notably,the serpentine configuration shows superior thermal homogeneity and heat distribution,with a 15.05%increase in heat gain at a 55℃ inlet temperature compared to the spiral design.The performance gap between the two layouts narrows as the inlet temperature increases from 50℃ in 5℃ increments by approximately 4.1%,3.7%,and 1.7%,respectively.Higher inlet temperatures also improve PCM discharging and charging rates,improving energy storage utilization.The findings provide significant design guidelines for sustainable heating systems for cold climates.
基金supported by the Science and Technology Fund Project of Guizhou Health Commission(gzwkj2025-163)。
文摘Objective:To identify the root causes of typical adverse drug events through the lens of patient experiences proposing novel strategies to mitigate preventable harm.Methods:A qualitative case study leveraging in-depth interviews with patients and families,anchored by Interactive Patient Par ticipation Theory,to analyze 4 high-severity adverse drug events(ADE)cases.Cases were purposively sampled from 8 communities in China's National Adverse Event Monitor Center(2018-2023).Semi-structured interviews explored patient perspectives,with data analyzed via thematic coding and triangulation against clinical records.Results:Five interconnected themes emerged:(1)erosion of trust,(2)communication breakdowns,(3)information asymmetry,(4)environmental inadequacies,and(5)technological alienation.Notably,75% of participants had≤high school education,and 50% used≥7 medications daily,compounding ADE risks.Conclusions:We considered elements mentioned by theory,exploring trust,communication,information,and suppor t as the root causes.In addition,we added“adaptability to new technology”as an impor tant and necessary component.It is impor tant and necessary to analyze typical adverse drug events from the perspectives of patients.
文摘Mindfulness would enhance university students’emotional well-being and study engagement.However,the role of affect(positive and negative emotions)and psychological resources(psychological capital)linking mindfulness to study engagement remain underexplored.This cross-sectional study surveyed 688 Chinese university students(females=413,mean age=20.3,SD=0.83),using validated self-report measures of mindfulness,positive and negative emotions,psychological capital,and study engagement.Structural equation modeling and bias-corrected bootstrap analyses(5000 resamples)revealed that mindfulness directly enhanced positive emotions,psychological capital,and study engagement,while reducing negative emotions.Positive emotions partially mediated the positive effect of mindfulness on psychological capital and study engagement.Negative emotions partially and negatively mediated only the mindfulness-psychological capital link.Psychological capital independently mediated the mindfulness-engagement relationship,and two sequential mediation pathways emerged:(a)mindfulness→positive emotions→psychological capital→higher study engagement and(b)mindfulness→reduced negative emotions→psychological capital→higher study engagement.Consistent with broaden-and-build(B&B)theory and Conservation of Resources(COR)theory,these findings suggest that mindfulness fosters study engagement primarily by promoting positive emotional experiences and strengthening psychological capital.By implication,university student support programs should employ mindfulness-based interventions to cultivate emotional and psychological resources for higher students’engagement and overall well-being.
