To enhance the accuracy of path planning of unmanned surface vehicles(USVs),the particle swarm optimization algorithm(PSO)is improved based on species migration strategies observed in ecology.By incorporating the conc...To enhance the accuracy of path planning of unmanned surface vehicles(USVs),the particle swarm optimization algorithm(PSO)is improved based on species migration strategies observed in ecology.By incorporating the concept of particle sight distance,an improved algorithm,called SD-IPSO,is proposed for the real-time autonomous navigation of USVs in marine environments.The algorithm refines the individual behavior pattern of particles in the population,effectively improving both local and global search capabilities while avoiding premature convergence.The effectiveness of the algorithm is validated using standard test functions from CEC-2017 function library,assessing it from multiple dimensions.Sensitivity analysis is conducted on key parameters in the algorithm,including particle sight distance and population size.Results indicate that compared with PSO,SD-IPSO demonstrates significant advantages in optimization accuracy and convergence speed.The application of SD-IPSO in path planning is further investigated through a 14-point traveling salesman problem(TSP)example and navigation autonomous tests of USVs in marine environments.Findings demonstrate that the proposed algorithm exhibits superior optimization capabilities and can effectively address the path planning challenges of USVs.展开更多
Maintaining the structural integrity of parallel natural gas pipelines during leakage-induced jet fires remains a critical engineering challenge.Existing methods often fail to account for the complex interactions amon...Maintaining the structural integrity of parallel natural gas pipelines during leakage-induced jet fires remains a critical engineering challenge.Existing methods often fail to account for the complex interactions among heat transfer,material behavior,and pipeline geometry,which can lead to overly simplified and potentially unsafe assessments.To address these limitations,this study develops a multiphysics approach that integrates small-orifice leakage theory with detailed thermo-fluid-structural simulations.The proposed framework contributes to a more accurate failure analysis through three main components:(1)coupled modeling that tracks transient heat flow and stress development as fire conditions evolve;(2)risk assessment incorporating spatial layout,material property changes with temperature,and operational limits;and(3)sensitivity analysis to identify key design factors that influence structural performance under high thermal loads.Simulation results demonstrate that thermal radiation from neighboring jet fires significantly accelerates material degradation,with inter-pipeline spacing emerging as a critical determinant of structural response.Notably,increasing the spacing between pipelines reduces thermal interaction and mechanical stress transfer.As a result,systems with optimized spacing exhibit markedly lower deformation than conventional configurations.These findings provide a foundation for re-evaluating pipeline layout strategies and strengthening safety protocols,particularly in high-risk environments where fire exposure can severely compromise structural reliability.The proposed approach offers actionable guidance for engineers and policymakers seeking to enhance the resilience of pipeline infrastructure under extreme thermal conditions.展开更多
Self-suspended proppants,which enable clear-water fracturing,represent a promising new class of materials for reservoir stimulation.Given the economic limitations associated with their exclusive use,this study investi...Self-suspended proppants,which enable clear-water fracturing,represent a promising new class of materials for reservoir stimulation.Given the economic limitations associated with their exclusive use,this study investigates proppant transport behavior in hybrid systems combining self-suspended proppants with conventional 40/70 mesh quartz sand at various mixing ratios.A dedicated experimental apparatus was developed to replicate field-relevant complex fracture networks,consisting of a main fracture and two branching fractures with different deflection angles.Using this system,sand bank formation and proppant distribution were examined for both conventional quartz sand fracturing and fracturing augmented with self-suspended proppants.The effects of slurry discharge volume,proppant mixing ratio,sand ratio,and injection location of the self-suspended proppant on transport and placement behavior were systematically analyzed.According to the results,the incorporation of self-suspended proppants markedly enhances the proppant-carrying capacity of the slurry and substantially modifies sand bank morphology.Increasing the discharge volume raises the inlet slope angle and promotes greater proppant penetration into branch fractures.The proportion of self-suspended proppant governs slurry viscoelasticity and,consequently,proppant settling behavior.As the fraction of self-suspended proppant decreases,the equilibrium height of the sand bank increases,while the proppant mass fraction within branch fractures exhibits a non-monotonic response,initially decreasing and then increasing.Variations in sand ratio alter both overall proppant concentration and the self-suspended proppant-to-water ratio,thereby modulating slurry rheology and influencing proppant placement.In addition,changes in injection location affect near-wellbore vortex structures,leading to distinct sand bank morphologies.展开更多
Railway noise barriers are an essential piece of infrastructure for reducing noise propagation.However,these barriers experience aerodynamic loads generated by high-speed trains,leading to dynamic effects that may com...Railway noise barriers are an essential piece of infrastructure for reducing noise propagation.However,these barriers experience aerodynamic loads generated by high-speed trains,leading to dynamic effects that may compromise their fatigue capacity.The most common structural design for railway noise barriers consists of vertical configurations of posts and panels.However,there have been few dynamic analyses of steel post/wood panel noise barriers under train-induced aerodynamic loads.This study used dynamic finite element analysis to assess the dynamic behavior of such noise barriers.Analysis of a 40-m-long noise barrier model and a triangular simplified load model,the latter of which effectively represented the detailed aerodynamic load,were first used to establish the model and input of the moving load during dynamic simulation.Then,the effects of different parameters on the dynamic response of the noise barrier were evaluated,including the damping ratio,the profile of the steel post,the span length of the panel,the barrier height,and the train speed.Gray relational analysis indicated that barrier height exhibited the highest correlations with the dynamic responses,followed by train speed,post profile,span length,and damping ratio.A reduction in the natural frequency and an increase in the train speed result in a higher peak response and more pronounced fluctuations between the nose and tail waves.The dynamic amplification factor(DAF)was found to be related to both the natural frequency and train speed.A model was proposed showing that the DAF significantly increases as the square of the natural frequency decreases and the cube of the train speed rises.展开更多
To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations,high-energy metal powders(aluminum(Al),boron(B),and magnesium hydride(MgH_(2)))are incorporated in...To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations,high-energy metal powders(aluminum(Al),boron(B),and magnesium hydride(MgH_(2)))are incorporated into a liquid fuel primarily composed of diethyl ether(DEE)and isopropyl nitrate(IPN).The explosion characteristics of different solid-liquid fuel-air-explosive(FAE)under unconfined conditions are investigated using a high-speed camera,infrared thermal imaging,and a pressure measurement system.Results demonstrate that high-energy metal powders significantly enhance detonation energy dissipation,with aluminum exhibiting the most pronounced effect.Fuel 5#(45.4 wt%DEE,9.2 wt%IPN,29.5 wt%Al,9.1 wt%B,6.8 wt%MgH_(2))exhibits superior explosion performance,achieving higher values of overpressure,impulse,and thermal radiation damage during the detonation stage compared to other fuels.However,Fuel 5#also displays faster decay rates,attributed to accelerated heat release rates induced by B and MgH_(2)powders.This study reveals that different metal powders in solid-liquid FAE exhibit distinct enhancements in explosion performance,providing critical insights for optimizing composite fuel design.展开更多
Recent studies indicate that millions of individuals suffer from renal diseases,with renal carcinoma,a type of kidney cancer,emerging as both a chronic illness and a significant cause of mortality.Magnetic Resonance I...Recent studies indicate that millions of individuals suffer from renal diseases,with renal carcinoma,a type of kidney cancer,emerging as both a chronic illness and a significant cause of mortality.Magnetic Resonance Imaging(MRI)and Computed Tomography(CT)have become essential tools for diagnosing and assessing kidney disorders.However,accurate analysis of thesemedical images is critical for detecting and evaluating tumor severity.This study introduces an integrated hybrid framework that combines three complementary deep learning models for kidney tumor segmentation from MRI images.The proposed framework fuses a customized U-Net and Mask R-CNN using a weighted scheme to achieve semantic and instance-level segmentation.The fused outputs are further refined through edge detection using Stochastic FeatureMapping Neural Networks(SFMNN),while volumetric consistency is ensured through Improved Mini-Batch K-Means(IMBKM)clustering integrated with an Encoder-Decoder Convolutional Neural Network(EDCNN).The outputs of these three stages are combined through a weighted fusion mechanism,with optimal weights determined empirically.Experiments on MRI scans from the TCGA-KIRC dataset demonstrate that the proposed hybrid framework significantly outperforms standalone models,achieving a Dice Score of 92.5%,an IoU of 87.8%,a Precision of 93.1%,a Recall of 90.8%,and a Hausdorff Distance of 2.8 mm.These findings validate that the weighted integration of complementary architectures effectively overcomes key limitations in kidney tumor segmentation,leading to improved diagnostic accuracy and robustness in medical image analysis.展开更多
The global energy demand is increasing rapidly,and it is imperative to develop shale hydrocarbon re-sources vigorously.The prerequisite for enhancing the exploitation efficiency of shale reservoirs is the systematic e...The global energy demand is increasing rapidly,and it is imperative to develop shale hydrocarbon re-sources vigorously.The prerequisite for enhancing the exploitation efficiency of shale reservoirs is the systematic elucidation of the occurrence characteristics,flow behavior,and enhanced oil recovery(EOR)mechanisms of shale oil within commonly developed nanopores.Molecular dynamics(MD)technique can simulate the occurrence,flow,and extraction processes of shale oil at the nanoscale,and then quantitatively characterize various fluid properties,flow characteristics,and action mechanisms under different reservoir conditions by calculating and analyzing a series of MD parameters.However,the existing review on the application of MD simulation in shale oil reservoirs is not systematic enough and lacks a summary of technical challenges and solutions.Therefore,recent MD studies on shale oil res-ervoirs were summarized and analyzed.Firstly,the applicability of force fields and ensembles of MD in shale reservoirs with different reservoir conditions and fluid properties was discussed.Subsequently,the calculation methods and application examples of MD parameters characterizing various properties of fluids at the microscale were summarized.Then,the application of MD simulation in the study of shale oil occurrence characteristics,flow behavior,and EOR mechanisms was reviewed,along with the elucidation of corresponding micro-mechanisms.Moreover,influencing factors of pore structure,wall properties,reservoir conditions,fluid components,injection/production parameters,formation water,and inorganic salt ions were analyzed,and some new conclusions were obtained.Finally,the main challenges associated with the application of MD simulations to shale oil reservoirs were discussed,and reasonable prospects for future MD research directions were proposed.The purpose of this review is to provide theoretical basis and methodological support for applying MD simulation to study shale oil reservoirs.展开更多
The global reliance on phosphate rock for agriculture and other industries,coupled with chemical regulations in developed countries,has driven the search for green alternatives in apatite flotation.This review investi...The global reliance on phosphate rock for agriculture and other industries,coupled with chemical regulations in developed countries,has driven the search for green alternatives in apatite flotation.This review investigates eco-friendly collectors’effectiveness in promoting sustainable mineral processing,guiding future alternatives to traditional reagents.The manuscript discussed the surface properties of apatite and its interaction with eco-friendly collectors,assessing existing fundamental studies.This study sought to:(1)define,organize,and classify“eco-friendly”collectors;(2)evaluate their effect in IEP and contact angle;(3)provide a better understanding of the adsorption behavior of the different fatty acid chains into apatite surface;(4)assess their ability to reversely and directly float apatite;(5)address gaps to achieve selectivity and process optimization.Outcomes demonstrated that fatty acids are largely applied,but other renewable sources of these reagents have been promisingly evaluated.In addition,other natural reagents have been tested,and new green synthetics have demonstrated synergistic effects when combined with fatty acids,yielding significant improvements in grade and recovery.However,collector effectiveness varies with ore characteristics,like particle size and surface properties,which remain underexplored.Future research should design tailored collectors that align with mineralogical differences to enhance selectivity.展开更多
Mitigating vortex-induced vibrations(VIV)in flexible risers represents a critical concern in offshore oil and gas production,considering its potential impact on operational safety and efficiency.The accurate predictio...Mitigating vortex-induced vibrations(VIV)in flexible risers represents a critical concern in offshore oil and gas production,considering its potential impact on operational safety and efficiency.The accurate prediction of displacement and position of VIV in flexible risers remains challenging under actual marine conditions.This study presents a data-driven model for riser displacement prediction that corresponds to field conditions.Experimental data analysis reveals that the XGBoost algorithm predicts the maximum displacement and position with superior accuracy compared with Support vector regression(SVR),considering both computational efficiency and precision.Platform displacement in the Y-direction demonstrates a significant positive correlation with both axial depth and maximum displacement magnitude.The fourth point displacement exhibits the highest contribution to model prediction outcomes,showing a positive influence on maximum displacement while negatively affecting the axial depth of maximum displacement.Platform displacement in the X-and Y-directions exhibits competitive effects on both the riser’s maximum displacement and its axial depth.Through the implementation of XGBoost algorithm and SHapley Additive exPlanation(SHAP)analysis,the model effectively estimates the riser’s maximum displacement and its precise location.This data-driven approach achieves predictions using minimal,readily available data points,enhancing its practical field applications and demonstrating clear relevance to academic and professional communities.展开更多
Effective management of water resources,especially groundwater,is crucial and requires a precise understanding of aquifer characteristics,imposed stresses,and the groundwater balance.Simulation-optimization models pla...Effective management of water resources,especially groundwater,is crucial and requires a precise understanding of aquifer characteristics,imposed stresses,and the groundwater balance.Simulation-optimization models plays a vital role in guiding planners toword sustainable long-term aquifer exploita-tion.This study simulated monthly water table variations in the Kashan Plain over a ten-year period from 2008 to 2019 across 125 stress periods using the GMS model.The model was calibrated for both steady-state and transient conditions for the 2008–2016 period and validated for the 2016–2019 period.Results indicated a 4.4 m decline in groundwater levels over the 10-year study period.Given the plain's location in a arid climatic zone with limited effective precipitation for aquifer recharge,the study focused on ground-water extraction management.A modified two-point hedging policy was employed as a solution to mitigate critical groundwater depletion,reducing the annual drawdown rate from 0.44 m to 0.31 m and conserving 255 million cubic meters(mcm)of water annually.Although this approach slightly decreased reliability(i.e.the number of months meeting full water demands),it effectively minimized the risk of severe droughts and irreparable damages.This policy offers managers a dynamical and intelligent tool for regulating groundwater extraction,balancing aquifer sustainability with agricultural and urban water requirements.展开更多
This study presents an enhanced convolutional neural network(CNN)model integrated with Explainable Artificial Intelligence(XAI)techniques for accurate prediction and interpretation of wheat crop diseases.The aim is to...This study presents an enhanced convolutional neural network(CNN)model integrated with Explainable Artificial Intelligence(XAI)techniques for accurate prediction and interpretation of wheat crop diseases.The aim is to streamline the detection process while offering transparent insights into the model’s decision-making to support effective disease management.To evaluate the model,a dataset was collected from wheat fields in Kotli,Azad Kashmir,Pakistan,and tested across multiple data splits.The proposed model demonstrates improved stability,faster conver-gence,and higher classification accuracy.The results show significant improvements in prediction accuracy and stability compared to prior works,achieving up to 100%accuracy in certain configurations.In addition,XAI methods such as Local Interpretable Model-agnostic Explanations(LIME)and Shapley Additive Explanations(SHAP)were employed to explain the model’s predictions,highlighting the most influential features contributing to classification decisions.The combined use of CNN and XAI offers a dual benefit:strong predictive performance and clear interpretability of outcomes,which is especially critical in real-world agricultural applications.These findings underscore the potential of integrating deep learning models with XAI to advance automated plant disease detection.The study offers a precise,reliable,and interpretable solution for improving wheat production and promoting agricultural sustainability.Future extensions of this work may include scaling the dataset across broader regions and incorporating additional modalities such as environmental data to enhance model robustness and generalization.展开更多
Diagnosing dental disorders using routine photographs can significantly reduce chair-side workload and expand access to care.However,most AI-based image analysis systems suffer from limited interpretability and are tr...Diagnosing dental disorders using routine photographs can significantly reduce chair-side workload and expand access to care.However,most AI-based image analysis systems suffer from limited interpretability and are trained on class-imbalanced datasets.In this study,we developed a balanced,transformer-based pipeline to detect three common dental disorders:tooth discoloration,calculus,and hypodontia,from standard color images.After applying a color-standardized preprocessing pipeline and performing stratified data splitting,the proposed vision transformer model was fine-tuned and subsequently evaluated using standard classification benchmarks.The model achieved an impressive accuracy of 98.94%,with precision,recall and F1 scores all greater than or equal to 98%for the three classes.To ensure interpretability,three complementary saliency methods,attention roll-out,layer-wise relevance propagation,and LIME,verified that predictions rely on clinically meaningful cues such as stained enamel,supragingival deposits,and edentulous gaps.The proposed method addresses class imbalance through dataset balancing,enhances interpretability using multiple explanation methods,and demonstrates the effectiveness of transformers over CNNs in dental imaging.This method offers a transparent,real-time screening tool suitable for both clinical and tele-dentistry frameworks,providing accessible,clarity-guided care pathways.展开更多
Shale gas production involves complex gas-water two-phase flow,with flow patterns in proppant-filled fractures playing a critical role in determining production efficiency.In this study,3D geometric models of 40/70 me...Shale gas production involves complex gas-water two-phase flow,with flow patterns in proppant-filled fractures playing a critical role in determining production efficiency.In this study,3D geometric models of 40/70 mesh ceramic particles and quartz sand proppant clusters were elaborated using computed tomography(CT)scanning.These models were used to develop a numerical simulation framework based on the lattice Boltzmann method(LBM),enabling the investigation of gas-water flow behavior within proppant-filled fractures under varying driving forces and surface tensions.Simulation results at a closure pressure of 15 MPa have revealed that ceramic particles exhibit a simpler and more porous internal structure than quartz sand of the same size.Under identical flow conditions,ceramic proppants demonstrate higher fluid replacement efficiency.Replacement efficiency increases with higher porosity,greater driving force,and lower surface tension.Furthermore,fluid displacement is strongly influenced by pore geometry:flow is faster in straighter and wider channels,with preferential movement through larger pores forming dominant flow paths.The replacement velocity exhibits a characteristic time evolution,initially rapid,then gradually decreasing,correlating positively with the development of these dominant channels.展开更多
To deeply analyze the impact of international student mobility on their internationalization capabilities in the field of Petroleum and Natural Gas Engineering,this study systematically reviewed the exchange dynamics ...To deeply analyze the impact of international student mobility on their internationalization capabilities in the field of Petroleum and Natural Gas Engineering,this study systematically reviewed the exchange dynamics of international students at Southwest Petroleum University from 2014 to 2024,as well as detailed data on students’overseas visits from 2016 to 2024,carefully outlining the trends and characteristics of student international mobility over the past decade.Based on this,using an evaluation system for internationalization capabilities constructed by the authors,which closely follows the characteristics of Petroleum and Natural Gas Engineering and covers key dimensions such as language skills,international perspective,cross-cultural communication,and global cooperation,graduate students from the research team of international students were selected as a sample group.Through a carefully designed survey questionnaire,their current internationalization capabilities were systematically evaluated.The results showed that compared to the benchmark level in 2019,students’internationalization capabilities have shown a significant improvement trend,especially in cross-cultural communication.This finding not only reveals the positive role of international student mobility in promoting academic exchanges and integration but also further emphasizes the unique value of multicultural integration in scientific research teams to enhance the internationalization capabilities of domestic students.展开更多
The international development of the petroleum industry has posed an urgent demand for the internationalization capabilities of both academic and professional master’s students.However,there is currently a shortage o...The international development of the petroleum industry has posed an urgent demand for the internationalization capabilities of both academic and professional master’s students.However,there is currently a shortage of such talent in the petroleum energy sector,along with a lack of a collaborative training system.Based on this,this study focuses on featured disciplines in the petroleum energy sector and systematically constructs an international talent training model centered around the“five-element synergy”of“government-school-enterprise-teacher-student.”Firstly,it defines the connotations of the five-element synergy:“government(strategic guidance)-school(platform support)-enterprise(demand verification)-teacher(leading transformation)-student(practical co-creation).”Secondly,it sets distinct training objectives for academic(focusing on academic innovation)and professional(emphasizing engineering practice)master’s students.Furthermore,it constructs a“categorized and layered,progressive and collaborative”curriculum system,builds an international faculty team through a“recruitment+training”dual-path approach,and cultivates students’sense of professional mission to“contribute to the nation’s energy sector”through a“macro+micro”perspective.This model provides a practical pathway for international talent training in the petroleum energy sector and holds significant importance for enhancing the overseas competitiveness of petroleum enterprises and safeguarding national energy security.展开更多
Hydrogen storage plays a crucial role in achieving net-zero emissions by enabling large-scale energy storage,balancing renewable energy fluctuations,and ensuring a stable supply for various applications.This study pro...Hydrogen storage plays a crucial role in achieving net-zero emissions by enabling large-scale energy storage,balancing renewable energy fluctuations,and ensuring a stable supply for various applications.This study provides a comprehensive analysis of hydrogen storage technologies,with a particular focus on underground storage in geological formations such as salt caverns,depleted gas reservoirs,and aquifers.These formations offer high-capacity storage solutions,with salt caverns capable of holding up to 6 TWh of hydrogen and depleted gas reservoirs exceeding 1 TWh per site.Case studies from leading projects demonstrate the feasibility of underground hydrogen storage(UHS)in reducing energy intermittency and enhancing supply security.Challenges such as hydrogen leakage,groundwater contamination,induced seismicity,and economic constraints remain critical concerns.Our findings highlight the technical,economic,and regulatory considerations for integrating UHS into the oil and gas industry,emphasizing its role in sustainable energy transition and decarbonization strategies.展开更多
To gain insight into the fine interfacial control mechanism exhibited by oxidant-coated Al powder to improve combustion performance,we prepared Al/AP and Al@AP composite fuels using ball milling and spray-drying techn...To gain insight into the fine interfacial control mechanism exhibited by oxidant-coated Al powder to improve combustion performance,we prepared Al/AP and Al@AP composite fuels using ball milling and spray-drying technology.The thermal reaction characteristics,AP decomposition behavior,and decomposition reaction pathways of Al/AP and Al@AP composite fuels were investigated using thermal analysis and Ab Initio Molecular Dynamics(AIMD)calculations.Under the influence of fine interfacial control,the low-temperature decomposition heat release peak of AP was delayed by 25.5℃,while the high-temperature decomposition peak was advanced by 36.2℃,leading to an increase in the decomposition heat release of AP from 410.7 J/g to 1068.7 J/g.Compared to the unclad structure,the apparent activation energy of AP in low-temperature decomposition increased,and slightly decreased during high-temperature decomposition in the Al@AP composite fuel.The physical model of AP decomposition shifted to the model with higher degrees of freedom and a faster diffusion rate,characterized by rapid bidirectional diffusion at the interface.Furthermore,due to fine interfacial control,the oxidation reaction pathway of Al has been altered,changing from the final products of AP decomposition(O_(2),Cl2,etc.)to the direct oxidation of AP decomposition intermediates(HClO,ClO_(2),etc.).This accelerated and strengthened the oxidation reaction process of Al.As a result of these performance improvements,the final combustion temperature of Al@AP in the Microcanonical Ensemble(NVE)system stabilized at 2370 K,which is significantly higher than 1400 K observed for Al/AP,indicating enhanced ignition and combustion performance.展开更多
This study investigates the impacts of climate change on temperature and precipitation patterns across four governorates in southern Iraq—Basrah,Thi Qar,Al Muthanna,and Messan—using an inte-grated modeling framework...This study investigates the impacts of climate change on temperature and precipitation patterns across four governorates in southern Iraq—Basrah,Thi Qar,Al Muthanna,and Messan—using an inte-grated modeling framework that combines the Long Ashton Research Station Weather Generator(LARS-WG)with three CMIP5-based Global Climate Models(Hadley Centre Global Environmental Model version 2-Earth System(HadGEM2-ES)),European Community Earth-System Model(EC-Earth),and Model for Interdisciplinary Research on Climate version 5(MIROC5).Projections were generated for three future time periods(2021–2040,2041–2060,and 2061–2080)under two Representative Concentration Pathways(RCP4.5 and RCP8.5).By integrating high-resolution climate simulations with localized drought risk analy-sis,this study provides a detailed outlook on climate change trends in the region.The novelty of this research lies in its high-resolution,station-level analysis and its integration of localized statistical downscal-ing techniques to enhance the spatial applicability of coarse GCM outputs.Model calibration and validation 2 were performed using historical climate data(1990–2020),resulting in high accuracy across all stations(R=0.91–0.99;RMSE=0.19–2.78),thus reinforcing the robustness of the projections.Results indicate a significant rise in average annual maximum and minimum temperatures,with increases ranging from 0.88°C to 3.68°C by the end of the century,particularly under the RCP8.5 scenario.Precipitation patterns exhibit pronounced interannual variability,with the highest predicted increases reaching up to 19.26 mm per season,depending on the model and location.These shifts suggest heightened vulnerability to drought and water scarcity,particularly in already arid regions such as Muthanna and Thi Qar.The findings under-score the urgent need for adaptive strategies in water resource management and agricultural planning,providing decision-makers with region-specific climate insights critical for sustainable development under changing climate conditions.展开更多
To investigate the differences in combustion and energy release characteristics of metastable intermolecular composite materials composed of aluminum alloys and polyvinylidene fluoride(PVDF)with different compositions...To investigate the differences in combustion and energy release characteristics of metastable intermolecular composite materials composed of aluminum alloys and polyvinylidene fluoride(PVDF)with different compositions,two types of alloys were selected:Al-Mg and Al-Si.Pure aluminum powder of the same size was also chosen for comparison.The PVDF-coated metal particle composites and the mixtures of PVDF with metal particles were prepared using electrospray(ES)and physical blending methods(PM),respectively.A systematic study was conducted on the morphology,compositional structure,combustion performance,energy release characteristics,and thermal reactivity of the fabricated composites and their combustion products through scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS),X-ray diffraction(XRD),combustion performance experiments,closed vessel pressure tests,and simultaneous thermogravimetric-differential scanning calorimetry(TG-DSC).The experimental results indicated that the PVDF-coated metal particles prepared by the electrospray method exhibited a distinct core-shell structure,with the metal particles in close contact with the PVDF matrix.Compared to the PM blended materials,the ES composites demonstrated superior combustion performance and energy release characteristics during combustion.Analysis of different metal fuel systems under identical preparation conditions revealed that Al-Mg and Al-Si fuels modulate the combustion and energy release properties of aluminum alloy-PVDF MICs through two distinct pathways.展开更多
Tight oil reservoirs face significant challenges,including rapid production decline,low recovery rates,and a lack of effective energy replenishment methods.In this study,a novel development model is proposed,based on ...Tight oil reservoirs face significant challenges,including rapid production decline,low recovery rates,and a lack of effective energy replenishment methods.In this study,a novel development model is proposed,based on inter-fracture injection following volumetric fracturing and relying on a high-temperature and high-pressure large-scale physical simulation system.Additionally,the CMG(Computer Modelling Group Ltd.,Calgary City,Canada)software is also used to elucidate the impact of various single factors on the production of horizontal wells while filtering out the interference of others.The effects of fracture spacing,fracture half-length,and the injection-production ratio are studied.Results indicate that under rejection pressures of 6.89,3.45,and 1.88 MPa,the times to establish stable flow are 50,193,and 395 min,respectively.Higher injection pressures lead to an increased oil recovery efficiency,with the highest observed efficiency at 16.93%.This indicates that,compared with conventional medium and high permeability reservoirs,tight oil reservoirs exhibit similar pore throats and larger capillary forces when oil and water flow in both phases.Higher pressures reduce capillary forces,displacing more oil droplets,thus enhancing oil recovery efficiency.Moreover,under inter-fracture displacement conditions,the pressure gradient at both the injection and production ends remain consistent,with minimal pressure loss near the wellbore.This feature ensures that the crude oil in the middle of the reservoir also possesses displacement energy,thereby enhancing overall crude oil displacement efficiency.展开更多
文摘To enhance the accuracy of path planning of unmanned surface vehicles(USVs),the particle swarm optimization algorithm(PSO)is improved based on species migration strategies observed in ecology.By incorporating the concept of particle sight distance,an improved algorithm,called SD-IPSO,is proposed for the real-time autonomous navigation of USVs in marine environments.The algorithm refines the individual behavior pattern of particles in the population,effectively improving both local and global search capabilities while avoiding premature convergence.The effectiveness of the algorithm is validated using standard test functions from CEC-2017 function library,assessing it from multiple dimensions.Sensitivity analysis is conducted on key parameters in the algorithm,including particle sight distance and population size.Results indicate that compared with PSO,SD-IPSO demonstrates significant advantages in optimization accuracy and convergence speed.The application of SD-IPSO in path planning is further investigated through a 14-point traveling salesman problem(TSP)example and navigation autonomous tests of USVs in marine environments.Findings demonstrate that the proposed algorithm exhibits superior optimization capabilities and can effectively address the path planning challenges of USVs.
文摘Maintaining the structural integrity of parallel natural gas pipelines during leakage-induced jet fires remains a critical engineering challenge.Existing methods often fail to account for the complex interactions among heat transfer,material behavior,and pipeline geometry,which can lead to overly simplified and potentially unsafe assessments.To address these limitations,this study develops a multiphysics approach that integrates small-orifice leakage theory with detailed thermo-fluid-structural simulations.The proposed framework contributes to a more accurate failure analysis through three main components:(1)coupled modeling that tracks transient heat flow and stress development as fire conditions evolve;(2)risk assessment incorporating spatial layout,material property changes with temperature,and operational limits;and(3)sensitivity analysis to identify key design factors that influence structural performance under high thermal loads.Simulation results demonstrate that thermal radiation from neighboring jet fires significantly accelerates material degradation,with inter-pipeline spacing emerging as a critical determinant of structural response.Notably,increasing the spacing between pipelines reduces thermal interaction and mechanical stress transfer.As a result,systems with optimized spacing exhibit markedly lower deformation than conventional configurations.These findings provide a foundation for re-evaluating pipeline layout strategies and strengthening safety protocols,particularly in high-risk environments where fire exposure can severely compromise structural reliability.The proposed approach offers actionable guidance for engineers and policymakers seeking to enhance the resilience of pipeline infrastructure under extreme thermal conditions.
基金the China National Petroleum Corporation’s Forward-Looking Fundamental Technology Breakthrough Project(2021DJ2305).
文摘Self-suspended proppants,which enable clear-water fracturing,represent a promising new class of materials for reservoir stimulation.Given the economic limitations associated with their exclusive use,this study investigates proppant transport behavior in hybrid systems combining self-suspended proppants with conventional 40/70 mesh quartz sand at various mixing ratios.A dedicated experimental apparatus was developed to replicate field-relevant complex fracture networks,consisting of a main fracture and two branching fractures with different deflection angles.Using this system,sand bank formation and proppant distribution were examined for both conventional quartz sand fracturing and fracturing augmented with self-suspended proppants.The effects of slurry discharge volume,proppant mixing ratio,sand ratio,and injection location of the self-suspended proppant on transport and placement behavior were systematically analyzed.According to the results,the incorporation of self-suspended proppants markedly enhances the proppant-carrying capacity of the slurry and substantially modifies sand bank morphology.Increasing the discharge volume raises the inlet slope angle and promotes greater proppant penetration into branch fractures.The proportion of self-suspended proppant governs slurry viscoelasticity and,consequently,proppant settling behavior.As the fraction of self-suspended proppant decreases,the equilibrium height of the sand bank increases,while the proppant mass fraction within branch fractures exhibits a non-monotonic response,initially decreasing and then increasing.Variations in sand ratio alter both overall proppant concentration and the self-suspended proppant-to-water ratio,thereby modulating slurry rheology and influencing proppant placement.In addition,changes in injection location affect near-wellbore vortex structures,leading to distinct sand bank morphologies.
基金financially supported by the Swedish Transport Administration(Trafikverket)through the“Excellence Area 4”and FOI-BBT program(Grant Nos.BBT-2019-022 and BBT-TRV 2024/132497).
文摘Railway noise barriers are an essential piece of infrastructure for reducing noise propagation.However,these barriers experience aerodynamic loads generated by high-speed trains,leading to dynamic effects that may compromise their fatigue capacity.The most common structural design for railway noise barriers consists of vertical configurations of posts and panels.However,there have been few dynamic analyses of steel post/wood panel noise barriers under train-induced aerodynamic loads.This study used dynamic finite element analysis to assess the dynamic behavior of such noise barriers.Analysis of a 40-m-long noise barrier model and a triangular simplified load model,the latter of which effectively represented the detailed aerodynamic load,were first used to establish the model and input of the moving load during dynamic simulation.Then,the effects of different parameters on the dynamic response of the noise barrier were evaluated,including the damping ratio,the profile of the steel post,the span length of the panel,the barrier height,and the train speed.Gray relational analysis indicated that barrier height exhibited the highest correlations with the dynamic responses,followed by train speed,post profile,span length,and damping ratio.A reduction in the natural frequency and an increase in the train speed result in a higher peak response and more pronounced fluctuations between the nose and tail waves.The dynamic amplification factor(DAF)was found to be related to both the natural frequency and train speed.A model was proposed showing that the DAF significantly increases as the square of the natural frequency decreases and the cube of the train speed rises.
基金supported by the National Natural Science Foundation of China(Grant No.12402432)Natural Science Foundation of Jiangsu Province of China(Grant No.BK20230936)Graduate Education and Teaching Reform Project of Nanjing University of Science and Technology(Grant No.KT2024_C14)。
文摘To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations,high-energy metal powders(aluminum(Al),boron(B),and magnesium hydride(MgH_(2)))are incorporated into a liquid fuel primarily composed of diethyl ether(DEE)and isopropyl nitrate(IPN).The explosion characteristics of different solid-liquid fuel-air-explosive(FAE)under unconfined conditions are investigated using a high-speed camera,infrared thermal imaging,and a pressure measurement system.Results demonstrate that high-energy metal powders significantly enhance detonation energy dissipation,with aluminum exhibiting the most pronounced effect.Fuel 5#(45.4 wt%DEE,9.2 wt%IPN,29.5 wt%Al,9.1 wt%B,6.8 wt%MgH_(2))exhibits superior explosion performance,achieving higher values of overpressure,impulse,and thermal radiation damage during the detonation stage compared to other fuels.However,Fuel 5#also displays faster decay rates,attributed to accelerated heat release rates induced by B and MgH_(2)powders.This study reveals that different metal powders in solid-liquid FAE exhibit distinct enhancements in explosion performance,providing critical insights for optimizing composite fuel design.
基金funded by the Ongoing Research Funding Program-Research Chairs(ORF-RC-2025-2400),King Saud University,Riyadh,Saudi Arabia。
文摘Recent studies indicate that millions of individuals suffer from renal diseases,with renal carcinoma,a type of kidney cancer,emerging as both a chronic illness and a significant cause of mortality.Magnetic Resonance Imaging(MRI)and Computed Tomography(CT)have become essential tools for diagnosing and assessing kidney disorders.However,accurate analysis of thesemedical images is critical for detecting and evaluating tumor severity.This study introduces an integrated hybrid framework that combines three complementary deep learning models for kidney tumor segmentation from MRI images.The proposed framework fuses a customized U-Net and Mask R-CNN using a weighted scheme to achieve semantic and instance-level segmentation.The fused outputs are further refined through edge detection using Stochastic FeatureMapping Neural Networks(SFMNN),while volumetric consistency is ensured through Improved Mini-Batch K-Means(IMBKM)clustering integrated with an Encoder-Decoder Convolutional Neural Network(EDCNN).The outputs of these three stages are combined through a weighted fusion mechanism,with optimal weights determined empirically.Experiments on MRI scans from the TCGA-KIRC dataset demonstrate that the proposed hybrid framework significantly outperforms standalone models,achieving a Dice Score of 92.5%,an IoU of 87.8%,a Precision of 93.1%,a Recall of 90.8%,and a Hausdorff Distance of 2.8 mm.These findings validate that the weighted integration of complementary architectures effectively overcomes key limitations in kidney tumor segmentation,leading to improved diagnostic accuracy and robustness in medical image analysis.
基金supported by the National Natural Science Foundation of China(52304021,52104022,52204031)the Natural Science Foundation of Sichuan Province(2022NSFSC0205,2024NSFSC0201,2023NSFSC0947)the National Science and Technology Major Projects of China(2017ZX05049006-010).
文摘The global energy demand is increasing rapidly,and it is imperative to develop shale hydrocarbon re-sources vigorously.The prerequisite for enhancing the exploitation efficiency of shale reservoirs is the systematic elucidation of the occurrence characteristics,flow behavior,and enhanced oil recovery(EOR)mechanisms of shale oil within commonly developed nanopores.Molecular dynamics(MD)technique can simulate the occurrence,flow,and extraction processes of shale oil at the nanoscale,and then quantitatively characterize various fluid properties,flow characteristics,and action mechanisms under different reservoir conditions by calculating and analyzing a series of MD parameters.However,the existing review on the application of MD simulation in shale oil reservoirs is not systematic enough and lacks a summary of technical challenges and solutions.Therefore,recent MD studies on shale oil res-ervoirs were summarized and analyzed.Firstly,the applicability of force fields and ensembles of MD in shale reservoirs with different reservoir conditions and fluid properties was discussed.Subsequently,the calculation methods and application examples of MD parameters characterizing various properties of fluids at the microscale were summarized.Then,the application of MD simulation in the study of shale oil occurrence characteristics,flow behavior,and EOR mechanisms was reviewed,along with the elucidation of corresponding micro-mechanisms.Moreover,influencing factors of pore structure,wall properties,reservoir conditions,fluid components,injection/production parameters,formation water,and inorganic salt ions were analyzed,and some new conclusions were obtained.Finally,the main challenges associated with the application of MD simulations to shale oil reservoirs were discussed,and reasonable prospects for future MD research directions were proposed.The purpose of this review is to provide theoretical basis and methodological support for applying MD simulation to study shale oil reservoirs.
基金financially supported by CAMM(Center of Advanced Mining and Metallurgy/Green Flotation),as a center of excellence at the Luleå University of Technology.
文摘The global reliance on phosphate rock for agriculture and other industries,coupled with chemical regulations in developed countries,has driven the search for green alternatives in apatite flotation.This review investigates eco-friendly collectors’effectiveness in promoting sustainable mineral processing,guiding future alternatives to traditional reagents.The manuscript discussed the surface properties of apatite and its interaction with eco-friendly collectors,assessing existing fundamental studies.This study sought to:(1)define,organize,and classify“eco-friendly”collectors;(2)evaluate their effect in IEP and contact angle;(3)provide a better understanding of the adsorption behavior of the different fatty acid chains into apatite surface;(4)assess their ability to reversely and directly float apatite;(5)address gaps to achieve selectivity and process optimization.Outcomes demonstrated that fatty acids are largely applied,but other renewable sources of these reagents have been promisingly evaluated.In addition,other natural reagents have been tested,and new green synthetics have demonstrated synergistic effects when combined with fatty acids,yielding significant improvements in grade and recovery.However,collector effectiveness varies with ore characteristics,like particle size and surface properties,which remain underexplored.Future research should design tailored collectors that align with mineralogical differences to enhance selectivity.
基金The research work was financially supported by the National Natural Science Foundation of China(Grant Nos.51979238 and 52301338)the Sichuan Science and Technology Program(Grant Nos.2023NSFSC1953 and 2023ZYD0140).
文摘Mitigating vortex-induced vibrations(VIV)in flexible risers represents a critical concern in offshore oil and gas production,considering its potential impact on operational safety and efficiency.The accurate prediction of displacement and position of VIV in flexible risers remains challenging under actual marine conditions.This study presents a data-driven model for riser displacement prediction that corresponds to field conditions.Experimental data analysis reveals that the XGBoost algorithm predicts the maximum displacement and position with superior accuracy compared with Support vector regression(SVR),considering both computational efficiency and precision.Platform displacement in the Y-direction demonstrates a significant positive correlation with both axial depth and maximum displacement magnitude.The fourth point displacement exhibits the highest contribution to model prediction outcomes,showing a positive influence on maximum displacement while negatively affecting the axial depth of maximum displacement.Platform displacement in the X-and Y-directions exhibits competitive effects on both the riser’s maximum displacement and its axial depth.Through the implementation of XGBoost algorithm and SHapley Additive exPlanation(SHAP)analysis,the model effectively estimates the riser’s maximum displacement and its precise location.This data-driven approach achieves predictions using minimal,readily available data points,enhancing its practical field applications and demonstrating clear relevance to academic and professional communities.
文摘Effective management of water resources,especially groundwater,is crucial and requires a precise understanding of aquifer characteristics,imposed stresses,and the groundwater balance.Simulation-optimization models plays a vital role in guiding planners toword sustainable long-term aquifer exploita-tion.This study simulated monthly water table variations in the Kashan Plain over a ten-year period from 2008 to 2019 across 125 stress periods using the GMS model.The model was calibrated for both steady-state and transient conditions for the 2008–2016 period and validated for the 2016–2019 period.Results indicated a 4.4 m decline in groundwater levels over the 10-year study period.Given the plain's location in a arid climatic zone with limited effective precipitation for aquifer recharge,the study focused on ground-water extraction management.A modified two-point hedging policy was employed as a solution to mitigate critical groundwater depletion,reducing the annual drawdown rate from 0.44 m to 0.31 m and conserving 255 million cubic meters(mcm)of water annually.Although this approach slightly decreased reliability(i.e.the number of months meeting full water demands),it effectively minimized the risk of severe droughts and irreparable damages.This policy offers managers a dynamical and intelligent tool for regulating groundwater extraction,balancing aquifer sustainability with agricultural and urban water requirements.
文摘This study presents an enhanced convolutional neural network(CNN)model integrated with Explainable Artificial Intelligence(XAI)techniques for accurate prediction and interpretation of wheat crop diseases.The aim is to streamline the detection process while offering transparent insights into the model’s decision-making to support effective disease management.To evaluate the model,a dataset was collected from wheat fields in Kotli,Azad Kashmir,Pakistan,and tested across multiple data splits.The proposed model demonstrates improved stability,faster conver-gence,and higher classification accuracy.The results show significant improvements in prediction accuracy and stability compared to prior works,achieving up to 100%accuracy in certain configurations.In addition,XAI methods such as Local Interpretable Model-agnostic Explanations(LIME)and Shapley Additive Explanations(SHAP)were employed to explain the model’s predictions,highlighting the most influential features contributing to classification decisions.The combined use of CNN and XAI offers a dual benefit:strong predictive performance and clear interpretability of outcomes,which is especially critical in real-world agricultural applications.These findings underscore the potential of integrating deep learning models with XAI to advance automated plant disease detection.The study offers a precise,reliable,and interpretable solution for improving wheat production and promoting agricultural sustainability.Future extensions of this work may include scaling the dataset across broader regions and incorporating additional modalities such as environmental data to enhance model robustness and generalization.
文摘Diagnosing dental disorders using routine photographs can significantly reduce chair-side workload and expand access to care.However,most AI-based image analysis systems suffer from limited interpretability and are trained on class-imbalanced datasets.In this study,we developed a balanced,transformer-based pipeline to detect three common dental disorders:tooth discoloration,calculus,and hypodontia,from standard color images.After applying a color-standardized preprocessing pipeline and performing stratified data splitting,the proposed vision transformer model was fine-tuned and subsequently evaluated using standard classification benchmarks.The model achieved an impressive accuracy of 98.94%,with precision,recall and F1 scores all greater than or equal to 98%for the three classes.To ensure interpretability,three complementary saliency methods,attention roll-out,layer-wise relevance propagation,and LIME,verified that predictions rely on clinically meaningful cues such as stained enamel,supragingival deposits,and edentulous gaps.The proposed method addresses class imbalance through dataset balancing,enhances interpretability using multiple explanation methods,and demonstrates the effectiveness of transformers over CNNs in dental imaging.This method offers a transparent,real-time screening tool suitable for both clinical and tele-dentistry frameworks,providing accessible,clarity-guided care pathways.
文摘Shale gas production involves complex gas-water two-phase flow,with flow patterns in proppant-filled fractures playing a critical role in determining production efficiency.In this study,3D geometric models of 40/70 mesh ceramic particles and quartz sand proppant clusters were elaborated using computed tomography(CT)scanning.These models were used to develop a numerical simulation framework based on the lattice Boltzmann method(LBM),enabling the investigation of gas-water flow behavior within proppant-filled fractures under varying driving forces and surface tensions.Simulation results at a closure pressure of 15 MPa have revealed that ceramic particles exhibit a simpler and more porous internal structure than quartz sand of the same size.Under identical flow conditions,ceramic proppants demonstrate higher fluid replacement efficiency.Replacement efficiency increases with higher porosity,greater driving force,and lower surface tension.Furthermore,fluid displacement is strongly influenced by pore geometry:flow is faster in straighter and wider channels,with preferential movement through larger pores forming dominant flow paths.The replacement velocity exhibits a characteristic time evolution,initially rapid,then gradually decreasing,correlating positively with the development of these dominant channels.
基金Key Project of Postgraduate Education and Teaching Reform and Research at Southwest Petroleum University(Project No.:2022JG003)Degree and Postgraduate Education Research Project of Association of Chinese Graduate Education(Project No.:2020MSA346)Higher Education Teaching Reform Research Project of Southwest Petroleum University(Project No.:X2021JGYB003)。
文摘To deeply analyze the impact of international student mobility on their internationalization capabilities in the field of Petroleum and Natural Gas Engineering,this study systematically reviewed the exchange dynamics of international students at Southwest Petroleum University from 2014 to 2024,as well as detailed data on students’overseas visits from 2016 to 2024,carefully outlining the trends and characteristics of student international mobility over the past decade.Based on this,using an evaluation system for internationalization capabilities constructed by the authors,which closely follows the characteristics of Petroleum and Natural Gas Engineering and covers key dimensions such as language skills,international perspective,cross-cultural communication,and global cooperation,graduate students from the research team of international students were selected as a sample group.Through a carefully designed survey questionnaire,their current internationalization capabilities were systematically evaluated.The results showed that compared to the benchmark level in 2019,students’internationalization capabilities have shown a significant improvement trend,especially in cross-cultural communication.This finding not only reveals the positive role of international student mobility in promoting academic exchanges and integration but also further emphasizes the unique value of multicultural integration in scientific research teams to enhance the internationalization capabilities of domestic students.
基金Key Project of Postgraduate Education and Teaching Reform and Research at Southwest Petroleum University(2022JG003)Degree and Postgraduate Education Research Project at Association of Chinese Graduate Education(2020MSA346)+1 种基金Sichuan Provincial Society for Degree and Graduate Education(2023YB0406)Higher Education Teaching Reform Research Project at Southwest Petroleum University(X2021JGYB003)。
文摘The international development of the petroleum industry has posed an urgent demand for the internationalization capabilities of both academic and professional master’s students.However,there is currently a shortage of such talent in the petroleum energy sector,along with a lack of a collaborative training system.Based on this,this study focuses on featured disciplines in the petroleum energy sector and systematically constructs an international talent training model centered around the“five-element synergy”of“government-school-enterprise-teacher-student.”Firstly,it defines the connotations of the five-element synergy:“government(strategic guidance)-school(platform support)-enterprise(demand verification)-teacher(leading transformation)-student(practical co-creation).”Secondly,it sets distinct training objectives for academic(focusing on academic innovation)and professional(emphasizing engineering practice)master’s students.Furthermore,it constructs a“categorized and layered,progressive and collaborative”curriculum system,builds an international faculty team through a“recruitment+training”dual-path approach,and cultivates students’sense of professional mission to“contribute to the nation’s energy sector”through a“macro+micro”perspective.This model provides a practical pathway for international talent training in the petroleum energy sector and holds significant importance for enhancing the overseas competitiveness of petroleum enterprises and safeguarding national energy security.
基金Hakim Sabzevari University for supporting this research。
文摘Hydrogen storage plays a crucial role in achieving net-zero emissions by enabling large-scale energy storage,balancing renewable energy fluctuations,and ensuring a stable supply for various applications.This study provides a comprehensive analysis of hydrogen storage technologies,with a particular focus on underground storage in geological formations such as salt caverns,depleted gas reservoirs,and aquifers.These formations offer high-capacity storage solutions,with salt caverns capable of holding up to 6 TWh of hydrogen and depleted gas reservoirs exceeding 1 TWh per site.Case studies from leading projects demonstrate the feasibility of underground hydrogen storage(UHS)in reducing energy intermittency and enhancing supply security.Challenges such as hydrogen leakage,groundwater contamination,induced seismicity,and economic constraints remain critical concerns.Our findings highlight the technical,economic,and regulatory considerations for integrating UHS into the oil and gas industry,emphasizing its role in sustainable energy transition and decarbonization strategies.
基金co-supported by the National Natural Science Foundation of China(Nos.52176099 and 52306130)the Applied Basic Research Project of Changzhou City,China(No.CJ20235033)the High-Performance Computation Laboratory of Hefei and Changzhou University,China.
文摘To gain insight into the fine interfacial control mechanism exhibited by oxidant-coated Al powder to improve combustion performance,we prepared Al/AP and Al@AP composite fuels using ball milling and spray-drying technology.The thermal reaction characteristics,AP decomposition behavior,and decomposition reaction pathways of Al/AP and Al@AP composite fuels were investigated using thermal analysis and Ab Initio Molecular Dynamics(AIMD)calculations.Under the influence of fine interfacial control,the low-temperature decomposition heat release peak of AP was delayed by 25.5℃,while the high-temperature decomposition peak was advanced by 36.2℃,leading to an increase in the decomposition heat release of AP from 410.7 J/g to 1068.7 J/g.Compared to the unclad structure,the apparent activation energy of AP in low-temperature decomposition increased,and slightly decreased during high-temperature decomposition in the Al@AP composite fuel.The physical model of AP decomposition shifted to the model with higher degrees of freedom and a faster diffusion rate,characterized by rapid bidirectional diffusion at the interface.Furthermore,due to fine interfacial control,the oxidation reaction pathway of Al has been altered,changing from the final products of AP decomposition(O_(2),Cl2,etc.)to the direct oxidation of AP decomposition intermediates(HClO,ClO_(2),etc.).This accelerated and strengthened the oxidation reaction process of Al.As a result of these performance improvements,the final combustion temperature of Al@AP in the Microcanonical Ensemble(NVE)system stabilized at 2370 K,which is significantly higher than 1400 K observed for Al/AP,indicating enhanced ignition and combustion performance.
文摘This study investigates the impacts of climate change on temperature and precipitation patterns across four governorates in southern Iraq—Basrah,Thi Qar,Al Muthanna,and Messan—using an inte-grated modeling framework that combines the Long Ashton Research Station Weather Generator(LARS-WG)with three CMIP5-based Global Climate Models(Hadley Centre Global Environmental Model version 2-Earth System(HadGEM2-ES)),European Community Earth-System Model(EC-Earth),and Model for Interdisciplinary Research on Climate version 5(MIROC5).Projections were generated for three future time periods(2021–2040,2041–2060,and 2061–2080)under two Representative Concentration Pathways(RCP4.5 and RCP8.5).By integrating high-resolution climate simulations with localized drought risk analy-sis,this study provides a detailed outlook on climate change trends in the region.The novelty of this research lies in its high-resolution,station-level analysis and its integration of localized statistical downscal-ing techniques to enhance the spatial applicability of coarse GCM outputs.Model calibration and validation 2 were performed using historical climate data(1990–2020),resulting in high accuracy across all stations(R=0.91–0.99;RMSE=0.19–2.78),thus reinforcing the robustness of the projections.Results indicate a significant rise in average annual maximum and minimum temperatures,with increases ranging from 0.88°C to 3.68°C by the end of the century,particularly under the RCP8.5 scenario.Precipitation patterns exhibit pronounced interannual variability,with the highest predicted increases reaching up to 19.26 mm per season,depending on the model and location.These shifts suggest heightened vulnerability to drought and water scarcity,particularly in already arid regions such as Muthanna and Thi Qar.The findings under-score the urgent need for adaptive strategies in water resource management and agricultural planning,providing decision-makers with region-specific climate insights critical for sustainable development under changing climate conditions.
基金the National Natural Science Foundation of China(NSFC,Grant Nos.52176114 and 52306145)Natural Science Foundation of Jiangsu Province(Grant No.BK20230929)+3 种基金China Postdoctoral Science Foundation(Grant No.2023M731693)Fundamental Research Funds for the Central Universities,Grant No.30924010505Jiangsu Funding Program for Excellent Postdoctoral Talentthe Center of Analytical Facilities,Nanjing University of Science and Technology for providing technical equipment support for this article。
文摘To investigate the differences in combustion and energy release characteristics of metastable intermolecular composite materials composed of aluminum alloys and polyvinylidene fluoride(PVDF)with different compositions,two types of alloys were selected:Al-Mg and Al-Si.Pure aluminum powder of the same size was also chosen for comparison.The PVDF-coated metal particle composites and the mixtures of PVDF with metal particles were prepared using electrospray(ES)and physical blending methods(PM),respectively.A systematic study was conducted on the morphology,compositional structure,combustion performance,energy release characteristics,and thermal reactivity of the fabricated composites and their combustion products through scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS),X-ray diffraction(XRD),combustion performance experiments,closed vessel pressure tests,and simultaneous thermogravimetric-differential scanning calorimetry(TG-DSC).The experimental results indicated that the PVDF-coated metal particles prepared by the electrospray method exhibited a distinct core-shell structure,with the metal particles in close contact with the PVDF matrix.Compared to the PM blended materials,the ES composites demonstrated superior combustion performance and energy release characteristics during combustion.Analysis of different metal fuel systems under identical preparation conditions revealed that Al-Mg and Al-Si fuels modulate the combustion and energy release properties of aluminum alloy-PVDF MICs through two distinct pathways.
基金supported by the Study on the Seepage Law of Typical Low-Grade Oil Reservoirs,New Methods for Enhancing Oil Recovery(2021DJ1102)the National Science and Technology Major Special Support Program(Grant No.2017ZX05064)the CNPC Innovation Foundation(Grant No.2022DQ02-0604).
文摘Tight oil reservoirs face significant challenges,including rapid production decline,low recovery rates,and a lack of effective energy replenishment methods.In this study,a novel development model is proposed,based on inter-fracture injection following volumetric fracturing and relying on a high-temperature and high-pressure large-scale physical simulation system.Additionally,the CMG(Computer Modelling Group Ltd.,Calgary City,Canada)software is also used to elucidate the impact of various single factors on the production of horizontal wells while filtering out the interference of others.The effects of fracture spacing,fracture half-length,and the injection-production ratio are studied.Results indicate that under rejection pressures of 6.89,3.45,and 1.88 MPa,the times to establish stable flow are 50,193,and 395 min,respectively.Higher injection pressures lead to an increased oil recovery efficiency,with the highest observed efficiency at 16.93%.This indicates that,compared with conventional medium and high permeability reservoirs,tight oil reservoirs exhibit similar pore throats and larger capillary forces when oil and water flow in both phases.Higher pressures reduce capillary forces,displacing more oil droplets,thus enhancing oil recovery efficiency.Moreover,under inter-fracture displacement conditions,the pressure gradient at both the injection and production ends remain consistent,with minimal pressure loss near the wellbore.This feature ensures that the crude oil in the middle of the reservoir also possesses displacement energy,thereby enhancing overall crude oil displacement efficiency.
