Bio-mediated soil improvement methods keep on gaining the attention of geotechnical engineers and researchers globally due to their nature-based elegance and eco-friendliness.Most prevalent bio-mediated soil improveme...Bio-mediated soil improvement methods keep on gaining the attention of geotechnical engineers and researchers globally due to their nature-based elegance and eco-friendliness.Most prevalent bio-mediated soil improvement methods include microbially induced carbonate precipitation(MICP)and enzyme-induced carbonate precipitation(EICP).During their processes,the bacteria/free urease hydrolyzes the urea into ammonium and carbonic acid,which is accompanied by a considerable increase of alkalinity(about pH 9.0).The major problem associated with the above techniques is the release of gaseous ammonia that is extremely detrimental.Therefore,this study aims to propose a new sustainable approach involving lactic acid bacteria to facilitate the calcium phosphate mineralization for the strengthening of sand matrix.The major objectives of this investigation are:(i)to evaluate the urease activity of the lactic acid bacteria under different temperatures,pH conditions and additions of metal ions,(ii)to assess the treated sand matrix,(iii)to perform cost analysis.The outcomes indicated that Limosilactobacillus sp.could effectively facilitate the urea hydrolysis,hence increasing the pH from acidic to neutral and providing a desirable environment for the calcium phosphate to mineralize within the voids of the sand.The addition of 0.01%Ni^(2+)in culture media was found to enhance the urease activity by 38.8%and compressive strength over 40%.A combined formation of amorphous-and whisker-like precipitates could bridge a larger area at particle-particle contact points,thereby faciliating a strong force-network in sand matrix.The mineralized calcium phosphate compound was found to be brushite.The cost herein for producing 1 L treatment solution was estimated to be about 2.5-folds and 11.8-folds lower compared to that of MICP and EICP treatment solutions,respectively.Moreover,since the treatment pH could potentially be regulated between acidic-neural range,it would greatly control the release of gaseous ammonia.With several environmental and economical benefits,the study has disclosed a new sustainable direction for sand improvement via the use of lactic acid bacteria.展开更多
As one of the oldest disciplines supporting the living and civilisation development of human beings,Geotechnical Engineering has continuously evolved and advanced through embracement of new sciences and technologies.B...As one of the oldest disciplines supporting the living and civilisation development of human beings,Geotechnical Engineering has continuously evolved and advanced through embracement of new sciences and technologies.Biogeotechnics is one such fast-developing new focus area within the geotechnical engineering family.It’s rapid development is due,at least in part,to the promise of contributions to sustainability,which has become one of the greatest challenges in the world.展开更多
In recent years,railway construction in China has developed vigorously.With continuous improvements in the highspeed railway network,the focus is gradually shifting from large-scale construction to large-scale operati...In recent years,railway construction in China has developed vigorously.With continuous improvements in the highspeed railway network,the focus is gradually shifting from large-scale construction to large-scale operations.However,several challenges have emerged within the high-speed railway dispatching and command system,including the heavy workload faced by dispatchers,the difficulty of quantifying subjective expertise,and the need for effective training of professionals.Amid the growing application of artificial intelligence technologies in railway systems,this study leverages Large Language Model(LLM)technology.LLMs bring enhanced intelligence,predictive capabilities,robust memory,and adaptability to diverse real-world scenarios.This study proposes a human-computer interactive intelligent scheduling auxiliary training system built on LLM technology.The system offers capabilities including natural dialogue,knowledge reasoning,and human feedback learning.With broad applicability,the system is suitable for vocational education,guided inquiry,knowledge-based Q&A,and other training scenarios.Validation results demonstrate its effectiveness in auxiliary training,providing substantial support for educators,students,and dispatching personnel in colleges and professional settings.展开更多
It has been well recognized that sand particles significantly affect the mechanical properties of reconstituted sandy clays,including the hosted clay and sand particles.However,interrelation between the permeability a...It has been well recognized that sand particles significantly affect the mechanical properties of reconstituted sandy clays,including the hosted clay and sand particles.However,interrelation between the permeability and compressibility of reconstituted sandy clays by considering the structural effects of sand particles is still rarely reported.For this,a series of consolidation-permeability coefficient tests were conducted on reconstituted sandy clays with different sand fractions(ψ_(ss)),initial void ratio of hosted clays(e_(c0))and void ratio at liquid limit of hosted clays(e_(cL)).The roles of ψ_(ss) in both the relationships of permeability coefficient of hosted clay(k_(v-hosted clay))versus effective vertical stress(σ'_(v))and void ratio of hosted clay(e_(c-hosted clay))versus σ'_(v) were analyzed.The results show that the permeability coefficient of reconstituted sandy clays(k_(v))is dominated by hosted clay(k_(v)=k_(v-hosted clay)).Both ψ_(ss) and σ'_(v) affect the k_(v) of sandy clays by changing the e_(c-hosted clay) at any given σ'_(v).Due to the partial contacts and densified clay bridges between the sand particles(i.e.structure effects),the e_(c-hosted clay) in sandy clays is higher than that in clays at the same σ'_(v)v.The k_(v)-e_(c-hosted clay) relationship of sandy clays is independent of σ'_(v) and ψ_(ss)but is a function of e_(cL).The types of hosted clays affect the k_(v) of sandy clays by changing the e_(cL).Based on the relationship between permeability coefficient and void ratio for the reconstituted clays,an empirical method for determining the k_(v) is proposed and validated for sandy clays.The predicted values are almost consistent with the measured values with k_(v-predicted)=k_(v-measured)=0.6-2.5.展开更多
Discrete element method(DEM)-based numerical models in the YADE environment are used to simulate the constitutive response of uncemented and bio-cemented sands to investigate the influence of boundary conditions,loadi...Discrete element method(DEM)-based numerical models in the YADE environment are used to simulate the constitutive response of uncemented and bio-cemented sands to investigate the influence of boundary conditions,loading and testing conditions,and material types.Both the classical DEM model and the pore scale finite volume(PFV)-coupled DEM model are used to simulate the response of saturated uncemented and lightly cemented sands with a rigid wall boundary under both drained and undrained triaxial compression.A DEM model with flexible boundaries created using particle facet(PFacet)elements is used to simulate undrained triaxial compression of moderately cemented sands,including the influence of confining stress.The PFacet-based model is used to predict the transition from barreling failure to shear banding when the confining stress or the cementation degree increases.The classical DEM model with cohesive bonds of uniform strength is also used to successfully simulate the uniaxial compression response of a sand with an extremely high degree of cementation.Finally,this paper presents a particle-packing model consisting of multiple solid phases for cemented sands based on the understanding that not all particle types will have the same cohesive properties.This multiple solidphase model is a refinement of the classical DEM model that represents the particle physics more realistically,especially for heterogeneous systems.A preliminary parametric study is carried out considering varying cohesive properties and volume fractions for the different solid phases.展开更多
This study conducts a thorough examination of honeycomb sandwich panels with a lattice core,adopting advanced computational techniques for their modeling.The research extends its analysis to investigate the natural fr...This study conducts a thorough examination of honeycomb sandwich panels with a lattice core,adopting advanced computational techniques for their modeling.The research extends its analysis to investigate the natural frequency behavior of sandwich panels,encompassing the comprehensive assessment of the entire panel structure.At its core,the research applies the Representative Volume Element(RVE)theory to establish the equivalent material properties,thereby enhancing the predictive capabilities of lattice structure simulations.Themethodology applies these properties in the core of infinite panels,which are modeled using double periodic boundary conditions to explore their natural frequencies.Expanding beyond mere material characterization,the study introduces a novel approach to defining the material within the panel cores.By incorporating alternate materials such as steel and AlSiC,and by strategically modifying their ratios,the research streamlines the process of material variation without resorting to repetitive 3D operations on the constituent cells.This optimizes not only the computational resources but also offers insights into the structural response under diverse material compositions.Furthermore,the investigation extends its scope to analyze the influence of curvature on the structural behavior of lattice structures.Panels are modeled with varying degrees of curvature,ranging from single to double curvatures,including cylindrical and spherical configurations,across a spectrum of radii.A rigorous analysis is performed to study the effect of curvature on the mechanical performance and stability of lattice structures,offering valuable insights for design optimization and structural engineering applications.By building upon the existing knowledge and introducing innovative methodologies,this study contributes to improving the understanding of lattice structures and their applicability in diverse engineering contexts.展开更多
The inefficiency of photocatalytic overall water splitting is well documented and has been extensively studied.However,a crucial aspect of this process,the side reaction,has often been overlooked.In this study,we inve...The inefficiency of photocatalytic overall water splitting is well documented and has been extensively studied.However,a crucial aspect of this process,the side reaction,has often been overlooked.In this study,we investigate the impact of side reactions on photocatalytic overall water splitting by monitoring factors such as dissolved oxygen,reactive oxygen species,and hydrogen peroxide.Further insights into the side reaction are obtained through the introduction of a platinum cocatalyst.Our findings reveal that dissolved oxygen significantly contributes to the side reaction by promoting the production of hydrogen peroxide.This byproduct is generated at the expense of electrons needed for the hydrogen evolution reaction,thereby reducing the overall efficiency of photocatalytic water splitting.This article aims to provide guidance on future research directions in the field of water splitting,with a particular emphasis on photocatalysis.展开更多
Civil infrastructure is continuously subject to aging and deterioration due to multiple factors,which lead to a decline in performance and impact structural health.Accumulated damage on structures increases operationa...Civil infrastructure is continuously subject to aging and deterioration due to multiple factors,which lead to a decline in performance and impact structural health.Accumulated damage on structures increases operational costs and poses significant risks to public safety.Effective maintenance,repair,and rehabilitation strategies are needed to ensure civil infrastructure’s overall safety and reliability.Non-Destructive Evaluation(NDE)methods are utilized to assess latent damage and provide decision-makers with real-time information for mitigating hazards.Within the last decade,there has been a significant increase in the research and development of innovative NDE techniques to improve data processing and promote efficient and accurate infrastructure assessment.This paper aims to review one of those methods,namely,Infrared Thermography(IRT),and its applications in civil infrastructure.A comprehensive review is presented by investigating numerous journal articles,research papers,and technical reports describing numerous IRT applications for bridges,buildings,and general civil structures made from different materials.The capability of IRT to identify and pinpoint anomalies,typically in the early stages of degradation,has excellent potential to improve the safety and shore up the dependability of civil infrastructures while reducing expenses tied to maintenance and rehabilitation.Furthermore,the non-invasive nature of IRT is beneficial in mitigating disturbances and downtime that may occur during various inspection procedures.It is highlighted that IRT is a highly versatile and effective tool for infrastructure condition assessment.With further advancement and fine-tuning of the available techniques,it is likely that IRT will continue to gain significant popularity in maintaining and monitoring civil infrastructure.展开更多
Enzyme induced carbonate precipitation(EICP)is a promising technique in the field of biocementation due to its efficiency and controllability.Although many studies have proved its reliability in different environment,...Enzyme induced carbonate precipitation(EICP)is a promising technique in the field of biocementation due to its efficiency and controllability.Although many studies have proved its reliability in different environment,little attention has been paid to the influence of humic substances on the EICP.Humic substances cover most of the surface soil across the world land with vegetation,which varies according to the density of vegetation and climate.To understand the compatibility of this technique to distinct problematic soils,it is important to figure out how humic substances could affect the carbonate precipitation process induced by urease enzyme.Therefore,this study aims to investigate the effects of humic acid(HA),one type of humic substance,on the soil solidification through EICP.For this purpose,HA was added to natural soil with varying addition amounts(0%,1%,2%,4%,8%,16%)in soil column solidification tests.The results found that the cementation effectiveness was enhanced by a small amount of HA addition(<4%),while an addition up to 8%greatly inhibited the formation of calcium carbonate.At the same time,soil samples were buffered by HA in a weak acidic condition,thus preventing the emission of undesirable by-product ammonia in the ureolysis process.Therefore,this study makes a contribution to research on enzymatic biocementation by demonstrating the effects of HA on the cementation effectiveness of EICP technique.展开更多
Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in ...Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance.Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete.This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection,thus enhancing the performance and durability of concrete blocks.Enzyme induced carbonate precipitation(EICP)is one of the promising bio-cement methods.Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media.The treated blocks were tested for water absorption,ultrasonic pulse velocity(UPV)measurements,unconfined compressive strength(UCS),thermal performance,and scanning electron microscopy(SEM).The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55%reduction in water absorption,a 15%higher UCS and a 6.7%higher UPV when compared with control blocks.The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete.Although most of the posttreatment strategies investigated herein were found to be operative,a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media(CM).With the successful demonstration,the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.展开更多
Soil-bentonite(SB)backfills in vertical cutoff walls are used extensively to contain contaminated groundwater.Previous studies show that the hydraulic conductivity of backfill can exceed the typically recommended maxi...Soil-bentonite(SB)backfills in vertical cutoff walls are used extensively to contain contaminated groundwater.Previous studies show that the hydraulic conductivity of backfill can exceed the typically recommended maximum value(k=1×10^(−9) m/s)if exposed to groundwater impacted by organic acids commonly released from uncontrolled landfills and municipal solid waste dumps.Polymer amended backfills exhibit excellent chemical compatibility to metal-laden groundwater.However,few studies to date have explored the effect of organic acid contaminated groundwater on hydraulic performance of polymer amended backfills.This study presents an experimental investigation on the hydraulic performance and microstructural properties of a composite polymer amended backfill used to contain flow of acetic acid-laden groundwater.A series of laboratory experiments were performed to evaluate free-swell indices of the composite polymer amended bentonites,liquid limits of the composite polymer amended and unamended bentonites,and slump heights and hydraulic conductivity(k)values of the amended backfills to acetic acid solutions with varying concentrations.The results were compared with those of the unamended bentonites and unamended backfills reported in a previous study.The results showed that the free-swell index and liquid limit of the amended bentonites were higher than those of the unamended bentonites.Permeation with acetic acid solutions with concentrations ranging from 40 mmol/L to 320 mmol/L conducted on the amended backfill only resulted in an increase in k of less than a factor of about 10 related to that based on permeation with tap water(4.41×10^(−11)-1.68×10^(−10) m/s to acetic acid solution versus 1.65×10^(−11) m/s to tap water).Mechanisms contributing to enhanced chemical compatibility of amended backfill were ascertained based on scanning electron microscopy,mercury intrusion porosimetry,and zeta potential analyses.展开更多
Content-Based Image Retrieval(CBIR)and image mining are becoming more important study fields in computer vision due to their wide range of applications in healthcare,security,and various domains.The image retrieval sy...Content-Based Image Retrieval(CBIR)and image mining are becoming more important study fields in computer vision due to their wide range of applications in healthcare,security,and various domains.The image retrieval system mainly relies on the efficiency and accuracy of the classification models.This research addresses the challenge of enhancing the image retrieval system by developing a novel approach,EfficientNet-Convolutional Neural Network(EffNet-CNN).The key objective of this research is to evaluate the proposed EffNet-CNN model’s performance in image classification,image mining,and CBIR.The novelty of the proposed EffNet-CNN model includes the integration of different techniques and modifications.The model includes the Mahalanobis distance metric for feature matching,which enhances the similarity measurements.The model extends EfficientNet architecture by incorporating additional convolutional layers,batch normalization,dropout,and pooling layers for improved hierarchical feature extraction.A systematic hyperparameter optimization using SGD,performance evaluation with three datasets,and data normalization for improving feature representations.The EffNet-CNN is assessed utilizing precision,accuracy,F-measure,and recall metrics across MS-COCO,CIFAR-10 and 100 datasets.The model achieved accuracy values ranging from 90.60%to 95.90%for the MS-COCO dataset,96.8%to 98.3%for the CIFAR-10 dataset and 92.9%to 98.6%for the CIFAR-100 dataset.A validation of the EffNet-CNN model’s results with other models reveals the proposed model’s superior performance.The results highlight the potential of the EffNet-CNN model proposed for image classification and its usefulness in image mining and CBIR.展开更多
In light of growing challenges posed by water pollution,understanding the multifaceted impacts of water quality on economic performance is an imperative for formulating effective policies aimed at sustainable developm...In light of growing challenges posed by water pollution,understanding the multifaceted impacts of water quality on economic performance is an imperative for formulating effective policies aimed at sustainable development.Existing studies tend to be constrained by limited local data,and lack a perspective on spatial dynamics and regional variations in water quality effects.This study addresses these gaps by examining the influence of upstream water quality on downstream economic growth in China,utilizing high-resolution panel data.Findings reveal that a 1%increase in upstream biochemical oxygen demand(BOD)concentration reduces downstream economic growth by 0.25% nationally.Regionally,the constraining effect varies significantly,ranging from 0.38% in Southwest China(β=-0.38)to 0.92% in North China(β=-0.92).Notably,even in regions with non-polluted water,upstream water quality deterioration continues to impede downstream economic growth.These findings underscore the critical need to integrate water quality considerations into economic policy frameworks and highlight the importance of coordinated,cross-regional water quality management strategies to foster sustainable economic development.展开更多
Pleurotus ostreatus,a saprotrophic fungus,has been proposed for the remediation of organic contaminants in soils and more recently for modifying the hydraulic and mechanical behaviour of granular soils.The in situ per...Pleurotus ostreatus,a saprotrophic fungus,has been proposed for the remediation of organic contaminants in soils and more recently for modifying the hydraulic and mechanical behaviour of granular soils.The in situ perfor-mance of fungal-based biotechnologies will be controlled by the fungal growth and associated biochemical activity that can be achieved in soil.In this study,the influence of environmental conditions(temperature,degree of saturation),substrate type(lignocellulose and spent coffee grounds)and concentration on the my-celium growth of P.ostreatus in sand are investigated.Furthermore,the evolution of growth/survival indicators(respiration,ergosterol concentration)and enzymatic activity(laccase,manganese peroxidase)are investigated.Temperature was shown to have a strong influence on the growth of P.ostreatus in sand:growth was observed to be delayed at low temperatures(e.g.5℃),whereas growth was prevented at high temperatures(e.g.35℃).No growth was observed at very low degrees of saturation(S,=0%and 1.2%),indicating there is a critical water content required to support P.ostreatus growth.Within the mid-range of water contents tested radially,growth of P.ostreatus was similar.However,growth under saturated soil conditions was restricted to the air-water at-mosphere due to the requirement for oxygen availability.Low substrate concentrations(1%-5%)resulted in high radial growth of P.ostreatus,whereas increasing substrate content further acted to reduce radial growth,but visual observations indicated that fungal biomass density increased.These results are important for under-standing the feasibility of P.ostreatus growth under specific site conditions and for the design of successful treatment strategies.展开更多
An efficient algorithm for path planning is crucial for guiding autonomous surface vehicles(ASVs)through designated waypoints.However,current evaluations of ASV path planning mainly focus on comparing total path lengt...An efficient algorithm for path planning is crucial for guiding autonomous surface vehicles(ASVs)through designated waypoints.However,current evaluations of ASV path planning mainly focus on comparing total path lengths,using temporal models to estimate travel time,idealized integration of global and local motion planners,and omission of external environmental disturbances.These rudimentary criteria cannot adequately capture real-world operations.To address these shortcomings,this study introduces a simulation framework for evaluating navigation modules designed for ASVs.The proposed framework is implemented on a prototype ASV using the Robot Operating System(ROS)and the Gazebo simulation platform.The implementation processes replicated satellite images with the extended Kalman filter technique to acquire localized location data.Cost minimization for global trajectories is achieved through the application of Dijkstra and A*algorithms,while local obstacle avoidance is managed by the dynamic window approach algorithm.The results demonstrate the distinctions and intricacies of the metrics provided by the proposed simulation framework compared with the rudimentary criteria commonly utilized in conventional path planning works.展开更多
Impinging jet arrays are extensively used in numerous industrial operations,including the cooling of electronics,turbine blades,and other high-heat flux systems because of their superior heat transfer capabilities.Opt...Impinging jet arrays are extensively used in numerous industrial operations,including the cooling of electronics,turbine blades,and other high-heat flux systems because of their superior heat transfer capabilities.Optimizing the design and operating parameters of such systems is essential to enhance cooling efficiency and achieve uniform pressure distribution,which can lead to improved system performance and energy savings.This paper presents two multi-objective optimization methodologies for a turbulent air jet impingement cooling system.The governing equations are resolved employing the commercial computational fluid dynamics(CFD)software ANSYS Fluent v17.The study focuses on four controlling parameters:Reynolds number(Re),swirl number(S),jet-to-jet separation distance(Z/D),and impingement height(H/D).The effects of these parameters on heat transfer and impingement pressure distribution are investigated.Non-dominated Sorting Genetic Algorithm(NSGA-II)and Weighted Sum Method(WSM)are employed to optimize the controlling parameters for maximum cooling performance.The aim is to identify optimal design parameters and system configurations that enhance heat transfer efficiency while achieving a uniform impingement pressure distribution.These findings have practical implications for applications requiring efficient cooling.The optimized design achieved a 12.28%increase in convective heat transfer efficiency with a local Nusselt number of 113.05 compared to 100.69 in the reference design.Enhanced convective cooling and heat flux were observed in the optimized configuration,particularly in areas of direct jet impingement.Additionally,the optimized design maintained lower wall temperatures,demonstrating more effective thermal dissipation.展开更多
基金supported by the Japan Society for the Promotion of Science(JSPS)KAKENHI Grant Number JP22H01581the authors sincerely acknowledge the support.
文摘Bio-mediated soil improvement methods keep on gaining the attention of geotechnical engineers and researchers globally due to their nature-based elegance and eco-friendliness.Most prevalent bio-mediated soil improvement methods include microbially induced carbonate precipitation(MICP)and enzyme-induced carbonate precipitation(EICP).During their processes,the bacteria/free urease hydrolyzes the urea into ammonium and carbonic acid,which is accompanied by a considerable increase of alkalinity(about pH 9.0).The major problem associated with the above techniques is the release of gaseous ammonia that is extremely detrimental.Therefore,this study aims to propose a new sustainable approach involving lactic acid bacteria to facilitate the calcium phosphate mineralization for the strengthening of sand matrix.The major objectives of this investigation are:(i)to evaluate the urease activity of the lactic acid bacteria under different temperatures,pH conditions and additions of metal ions,(ii)to assess the treated sand matrix,(iii)to perform cost analysis.The outcomes indicated that Limosilactobacillus sp.could effectively facilitate the urea hydrolysis,hence increasing the pH from acidic to neutral and providing a desirable environment for the calcium phosphate to mineralize within the voids of the sand.The addition of 0.01%Ni^(2+)in culture media was found to enhance the urease activity by 38.8%and compressive strength over 40%.A combined formation of amorphous-and whisker-like precipitates could bridge a larger area at particle-particle contact points,thereby faciliating a strong force-network in sand matrix.The mineralized calcium phosphate compound was found to be brushite.The cost herein for producing 1 L treatment solution was estimated to be about 2.5-folds and 11.8-folds lower compared to that of MICP and EICP treatment solutions,respectively.Moreover,since the treatment pH could potentially be regulated between acidic-neural range,it would greatly control the release of gaseous ammonia.With several environmental and economical benefits,the study has disclosed a new sustainable direction for sand improvement via the use of lactic acid bacteria.
文摘As one of the oldest disciplines supporting the living and civilisation development of human beings,Geotechnical Engineering has continuously evolved and advanced through embracement of new sciences and technologies.Biogeotechnics is one such fast-developing new focus area within the geotechnical engineering family.It’s rapid development is due,at least in part,to the promise of contributions to sustainability,which has become one of the greatest challenges in the world.
基金the Talent Fund of Beijing Jiaotong University(Grant No.2024XKRC055).
文摘In recent years,railway construction in China has developed vigorously.With continuous improvements in the highspeed railway network,the focus is gradually shifting from large-scale construction to large-scale operations.However,several challenges have emerged within the high-speed railway dispatching and command system,including the heavy workload faced by dispatchers,the difficulty of quantifying subjective expertise,and the need for effective training of professionals.Amid the growing application of artificial intelligence technologies in railway systems,this study leverages Large Language Model(LLM)technology.LLMs bring enhanced intelligence,predictive capabilities,robust memory,and adaptability to diverse real-world scenarios.This study proposes a human-computer interactive intelligent scheduling auxiliary training system built on LLM technology.The system offers capabilities including natural dialogue,knowledge reasoning,and human feedback learning.With broad applicability,the system is suitable for vocational education,guided inquiry,knowledge-based Q&A,and other training scenarios.Validation results demonstrate its effectiveness in auxiliary training,providing substantial support for educators,students,and dispatching personnel in colleges and professional settings.
基金supported by the National Natural Science Foundation of China (Grant Nos.52278334 and 4197724)Fundamental Research Funds for the Central Universities (Grant No.2242024k30066).
文摘It has been well recognized that sand particles significantly affect the mechanical properties of reconstituted sandy clays,including the hosted clay and sand particles.However,interrelation between the permeability and compressibility of reconstituted sandy clays by considering the structural effects of sand particles is still rarely reported.For this,a series of consolidation-permeability coefficient tests were conducted on reconstituted sandy clays with different sand fractions(ψ_(ss)),initial void ratio of hosted clays(e_(c0))and void ratio at liquid limit of hosted clays(e_(cL)).The roles of ψ_(ss) in both the relationships of permeability coefficient of hosted clay(k_(v-hosted clay))versus effective vertical stress(σ'_(v))and void ratio of hosted clay(e_(c-hosted clay))versus σ'_(v) were analyzed.The results show that the permeability coefficient of reconstituted sandy clays(k_(v))is dominated by hosted clay(k_(v)=k_(v-hosted clay)).Both ψ_(ss) and σ'_(v) affect the k_(v) of sandy clays by changing the e_(c-hosted clay) at any given σ'_(v).Due to the partial contacts and densified clay bridges between the sand particles(i.e.structure effects),the e_(c-hosted clay) in sandy clays is higher than that in clays at the same σ'_(v)v.The k_(v)-e_(c-hosted clay) relationship of sandy clays is independent of σ'_(v) and ψ_(ss)but is a function of e_(cL).The types of hosted clays affect the k_(v) of sandy clays by changing the e_(cL).Based on the relationship between permeability coefficient and void ratio for the reconstituted clays,an empirical method for determining the k_(v) is proposed and validated for sandy clays.The predicted values are almost consistent with the measured values with k_(v-predicted)=k_(v-measured)=0.6-2.5.
基金support for this study from National Science Foundation(NSF)under the Engineering Research Centers(ERC)program,grant EEC-1449501.
文摘Discrete element method(DEM)-based numerical models in the YADE environment are used to simulate the constitutive response of uncemented and bio-cemented sands to investigate the influence of boundary conditions,loading and testing conditions,and material types.Both the classical DEM model and the pore scale finite volume(PFV)-coupled DEM model are used to simulate the response of saturated uncemented and lightly cemented sands with a rigid wall boundary under both drained and undrained triaxial compression.A DEM model with flexible boundaries created using particle facet(PFacet)elements is used to simulate undrained triaxial compression of moderately cemented sands,including the influence of confining stress.The PFacet-based model is used to predict the transition from barreling failure to shear banding when the confining stress or the cementation degree increases.The classical DEM model with cohesive bonds of uniform strength is also used to successfully simulate the uniaxial compression response of a sand with an extremely high degree of cementation.Finally,this paper presents a particle-packing model consisting of multiple solid phases for cemented sands based on the understanding that not all particle types will have the same cohesive properties.This multiple solidphase model is a refinement of the classical DEM model that represents the particle physics more realistically,especially for heterogeneous systems.A preliminary parametric study is carried out considering varying cohesive properties and volume fractions for the different solid phases.
文摘This study conducts a thorough examination of honeycomb sandwich panels with a lattice core,adopting advanced computational techniques for their modeling.The research extends its analysis to investigate the natural frequency behavior of sandwich panels,encompassing the comprehensive assessment of the entire panel structure.At its core,the research applies the Representative Volume Element(RVE)theory to establish the equivalent material properties,thereby enhancing the predictive capabilities of lattice structure simulations.Themethodology applies these properties in the core of infinite panels,which are modeled using double periodic boundary conditions to explore their natural frequencies.Expanding beyond mere material characterization,the study introduces a novel approach to defining the material within the panel cores.By incorporating alternate materials such as steel and AlSiC,and by strategically modifying their ratios,the research streamlines the process of material variation without resorting to repetitive 3D operations on the constituent cells.This optimizes not only the computational resources but also offers insights into the structural response under diverse material compositions.Furthermore,the investigation extends its scope to analyze the influence of curvature on the structural behavior of lattice structures.Panels are modeled with varying degrees of curvature,ranging from single to double curvatures,including cylindrical and spherical configurations,across a spectrum of radii.A rigorous analysis is performed to study the effect of curvature on the mechanical performance and stability of lattice structures,offering valuable insights for design optimization and structural engineering applications.By building upon the existing knowledge and introducing innovative methodologies,this study contributes to improving the understanding of lattice structures and their applicability in diverse engineering contexts.
基金supported by the National Key Research and Development Program of China(No.2022YFB3803600)the National Natural Science Foundation of China(Nos.22202187,22361142704,22238009,U24A2071,and 52272290)+4 种基金the National Postdoctoral Program for Innovative Talents(No.BX2021275)the Natural Science Foundation of Hubei Province of China(No.2022CFA001)the Project funded by China Postdoctoral Science Foundation(No.2022M712957)the Postdoctoral Funding Program of Hubei Province.Chuanbiao Bie and Bicheng Zhu would like to thank the China Scholarship Council(CSC)for its financial supportsupport from Australian Research Council Discovery Early Career Award(No.DE220100429).
文摘The inefficiency of photocatalytic overall water splitting is well documented and has been extensively studied.However,a crucial aspect of this process,the side reaction,has often been overlooked.In this study,we investigate the impact of side reactions on photocatalytic overall water splitting by monitoring factors such as dissolved oxygen,reactive oxygen species,and hydrogen peroxide.Further insights into the side reaction are obtained through the introduction of a platinum cocatalyst.Our findings reveal that dissolved oxygen significantly contributes to the side reaction by promoting the production of hydrogen peroxide.This byproduct is generated at the expense of electrons needed for the hydrogen evolution reaction,thereby reducing the overall efficiency of photocatalytic water splitting.This article aims to provide guidance on future research directions in the field of water splitting,with a particular emphasis on photocatalysis.
文摘Civil infrastructure is continuously subject to aging and deterioration due to multiple factors,which lead to a decline in performance and impact structural health.Accumulated damage on structures increases operational costs and poses significant risks to public safety.Effective maintenance,repair,and rehabilitation strategies are needed to ensure civil infrastructure’s overall safety and reliability.Non-Destructive Evaluation(NDE)methods are utilized to assess latent damage and provide decision-makers with real-time information for mitigating hazards.Within the last decade,there has been a significant increase in the research and development of innovative NDE techniques to improve data processing and promote efficient and accurate infrastructure assessment.This paper aims to review one of those methods,namely,Infrared Thermography(IRT),and its applications in civil infrastructure.A comprehensive review is presented by investigating numerous journal articles,research papers,and technical reports describing numerous IRT applications for bridges,buildings,and general civil structures made from different materials.The capability of IRT to identify and pinpoint anomalies,typically in the early stages of degradation,has excellent potential to improve the safety and shore up the dependability of civil infrastructures while reducing expenses tied to maintenance and rehabilitation.Furthermore,the non-invasive nature of IRT is beneficial in mitigating disturbances and downtime that may occur during various inspection procedures.It is highlighted that IRT is a highly versatile and effective tool for infrastructure condition assessment.With further advancement and fine-tuning of the available techniques,it is likely that IRT will continue to gain significant popularity in maintaining and monitoring civil infrastructure.
基金JST SPRING,Grant Number JPMJSP2119Japan Society for the Promotion of Science(JSPS)KAKENHI Grant Number JP22H01581。
文摘Enzyme induced carbonate precipitation(EICP)is a promising technique in the field of biocementation due to its efficiency and controllability.Although many studies have proved its reliability in different environment,little attention has been paid to the influence of humic substances on the EICP.Humic substances cover most of the surface soil across the world land with vegetation,which varies according to the density of vegetation and climate.To understand the compatibility of this technique to distinct problematic soils,it is important to figure out how humic substances could affect the carbonate precipitation process induced by urease enzyme.Therefore,this study aims to investigate the effects of humic acid(HA),one type of humic substance,on the soil solidification through EICP.For this purpose,HA was added to natural soil with varying addition amounts(0%,1%,2%,4%,8%,16%)in soil column solidification tests.The results found that the cementation effectiveness was enhanced by a small amount of HA addition(<4%),while an addition up to 8%greatly inhibited the formation of calcium carbonate.At the same time,soil samples were buffered by HA in a weak acidic condition,thus preventing the emission of undesirable by-product ammonia in the ureolysis process.Therefore,this study makes a contribution to research on enzymatic biocementation by demonstrating the effects of HA on the cementation effectiveness of EICP technique.
基金supported by the following two grants:(i)Japan Society for the Promotion of Science(JSPS)KAKENHI Grant Number JP22H01581(i)National Research Counsil(NRC)of Sri Lanka Investigator Driven Grant Number 22-041.
文摘Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance.Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete.This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection,thus enhancing the performance and durability of concrete blocks.Enzyme induced carbonate precipitation(EICP)is one of the promising bio-cement methods.Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media.The treated blocks were tested for water absorption,ultrasonic pulse velocity(UPV)measurements,unconfined compressive strength(UCS),thermal performance,and scanning electron microscopy(SEM).The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55%reduction in water absorption,a 15%higher UCS and a 6.7%higher UPV when compared with control blocks.The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete.Although most of the posttreatment strategies investigated herein were found to be operative,a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media(CM).With the successful demonstration,the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.
基金National Natural Science Foundation of China (Grant No.42177133)Primary R&D Plan of Jiangsu Province (Grant No.BE2022830)Primary R&D Plan of Anhui Province (Grant No.2023t07020018).
文摘Soil-bentonite(SB)backfills in vertical cutoff walls are used extensively to contain contaminated groundwater.Previous studies show that the hydraulic conductivity of backfill can exceed the typically recommended maximum value(k=1×10^(−9) m/s)if exposed to groundwater impacted by organic acids commonly released from uncontrolled landfills and municipal solid waste dumps.Polymer amended backfills exhibit excellent chemical compatibility to metal-laden groundwater.However,few studies to date have explored the effect of organic acid contaminated groundwater on hydraulic performance of polymer amended backfills.This study presents an experimental investigation on the hydraulic performance and microstructural properties of a composite polymer amended backfill used to contain flow of acetic acid-laden groundwater.A series of laboratory experiments were performed to evaluate free-swell indices of the composite polymer amended bentonites,liquid limits of the composite polymer amended and unamended bentonites,and slump heights and hydraulic conductivity(k)values of the amended backfills to acetic acid solutions with varying concentrations.The results were compared with those of the unamended bentonites and unamended backfills reported in a previous study.The results showed that the free-swell index and liquid limit of the amended bentonites were higher than those of the unamended bentonites.Permeation with acetic acid solutions with concentrations ranging from 40 mmol/L to 320 mmol/L conducted on the amended backfill only resulted in an increase in k of less than a factor of about 10 related to that based on permeation with tap water(4.41×10^(−11)-1.68×10^(−10) m/s to acetic acid solution versus 1.65×10^(−11) m/s to tap water).Mechanisms contributing to enhanced chemical compatibility of amended backfill were ascertained based on scanning electron microscopy,mercury intrusion porosimetry,and zeta potential analyses.
基金The authors extend their appreciation to the Deanship of Research and Graduate Studies at King Khalid University,Kingdom of Saudi Arabia,for funding this work through the Small Research Group Project under Grant Number RGP.1/316/45.
文摘Content-Based Image Retrieval(CBIR)and image mining are becoming more important study fields in computer vision due to their wide range of applications in healthcare,security,and various domains.The image retrieval system mainly relies on the efficiency and accuracy of the classification models.This research addresses the challenge of enhancing the image retrieval system by developing a novel approach,EfficientNet-Convolutional Neural Network(EffNet-CNN).The key objective of this research is to evaluate the proposed EffNet-CNN model’s performance in image classification,image mining,and CBIR.The novelty of the proposed EffNet-CNN model includes the integration of different techniques and modifications.The model includes the Mahalanobis distance metric for feature matching,which enhances the similarity measurements.The model extends EfficientNet architecture by incorporating additional convolutional layers,batch normalization,dropout,and pooling layers for improved hierarchical feature extraction.A systematic hyperparameter optimization using SGD,performance evaluation with three datasets,and data normalization for improving feature representations.The EffNet-CNN is assessed utilizing precision,accuracy,F-measure,and recall metrics across MS-COCO,CIFAR-10 and 100 datasets.The model achieved accuracy values ranging from 90.60%to 95.90%for the MS-COCO dataset,96.8%to 98.3%for the CIFAR-10 dataset and 92.9%to 98.6%for the CIFAR-100 dataset.A validation of the EffNet-CNN model’s results with other models reveals the proposed model’s superior performance.The results highlight the potential of the EffNet-CNN model proposed for image classification and its usefulness in image mining and CBIR.
基金National Natural Science Foundation of China,No.52370192,No.52200221,No.52200209Fundamental Research Funds for the Central Universities,No.2023CDSKXYGK011。
文摘In light of growing challenges posed by water pollution,understanding the multifaceted impacts of water quality on economic performance is an imperative for formulating effective policies aimed at sustainable development.Existing studies tend to be constrained by limited local data,and lack a perspective on spatial dynamics and regional variations in water quality effects.This study addresses these gaps by examining the influence of upstream water quality on downstream economic growth in China,utilizing high-resolution panel data.Findings reveal that a 1%increase in upstream biochemical oxygen demand(BOD)concentration reduces downstream economic growth by 0.25% nationally.Regionally,the constraining effect varies significantly,ranging from 0.38% in Southwest China(β=-0.38)to 0.92% in North China(β=-0.92).Notably,even in regions with non-polluted water,upstream water quality deterioration continues to impede downstream economic growth.These findings underscore the critical need to integrate water quality considerations into economic policy frameworks and highlight the importance of coordinated,cross-regional water quality management strategies to foster sustainable economic development.
基金support of the European Commission by way of the Marie Sklodowska-Curie Innovative Training Networks(ITN-ETN)project TERRE Training engineers and researchers to rethink geotechnical engineering for a low carbon future'(H2020-MSCA-ITN-2015-675762)the Engineering and Physical Sciences Research Council(EPSRC,EP/N035526/1)The contribution of El Mountassir to this work was also supported by a UKRI Future Leaders Fellowship(MR/V025376/1).
文摘Pleurotus ostreatus,a saprotrophic fungus,has been proposed for the remediation of organic contaminants in soils and more recently for modifying the hydraulic and mechanical behaviour of granular soils.The in situ perfor-mance of fungal-based biotechnologies will be controlled by the fungal growth and associated biochemical activity that can be achieved in soil.In this study,the influence of environmental conditions(temperature,degree of saturation),substrate type(lignocellulose and spent coffee grounds)and concentration on the my-celium growth of P.ostreatus in sand are investigated.Furthermore,the evolution of growth/survival indicators(respiration,ergosterol concentration)and enzymatic activity(laccase,manganese peroxidase)are investigated.Temperature was shown to have a strong influence on the growth of P.ostreatus in sand:growth was observed to be delayed at low temperatures(e.g.5℃),whereas growth was prevented at high temperatures(e.g.35℃).No growth was observed at very low degrees of saturation(S,=0%and 1.2%),indicating there is a critical water content required to support P.ostreatus growth.Within the mid-range of water contents tested radially,growth of P.ostreatus was similar.However,growth under saturated soil conditions was restricted to the air-water at-mosphere due to the requirement for oxygen availability.Low substrate concentrations(1%-5%)resulted in high radial growth of P.ostreatus,whereas increasing substrate content further acted to reduce radial growth,but visual observations indicated that fungal biomass density increased.These results are important for under-standing the feasibility of P.ostreatus growth under specific site conditions and for the design of successful treatment strategies.
基金Supported by the funding from RMIT Internal Research Grant R1.
文摘An efficient algorithm for path planning is crucial for guiding autonomous surface vehicles(ASVs)through designated waypoints.However,current evaluations of ASV path planning mainly focus on comparing total path lengths,using temporal models to estimate travel time,idealized integration of global and local motion planners,and omission of external environmental disturbances.These rudimentary criteria cannot adequately capture real-world operations.To address these shortcomings,this study introduces a simulation framework for evaluating navigation modules designed for ASVs.The proposed framework is implemented on a prototype ASV using the Robot Operating System(ROS)and the Gazebo simulation platform.The implementation processes replicated satellite images with the extended Kalman filter technique to acquire localized location data.Cost minimization for global trajectories is achieved through the application of Dijkstra and A*algorithms,while local obstacle avoidance is managed by the dynamic window approach algorithm.The results demonstrate the distinctions and intricacies of the metrics provided by the proposed simulation framework compared with the rudimentary criteria commonly utilized in conventional path planning works.
文摘Impinging jet arrays are extensively used in numerous industrial operations,including the cooling of electronics,turbine blades,and other high-heat flux systems because of their superior heat transfer capabilities.Optimizing the design and operating parameters of such systems is essential to enhance cooling efficiency and achieve uniform pressure distribution,which can lead to improved system performance and energy savings.This paper presents two multi-objective optimization methodologies for a turbulent air jet impingement cooling system.The governing equations are resolved employing the commercial computational fluid dynamics(CFD)software ANSYS Fluent v17.The study focuses on four controlling parameters:Reynolds number(Re),swirl number(S),jet-to-jet separation distance(Z/D),and impingement height(H/D).The effects of these parameters on heat transfer and impingement pressure distribution are investigated.Non-dominated Sorting Genetic Algorithm(NSGA-II)and Weighted Sum Method(WSM)are employed to optimize the controlling parameters for maximum cooling performance.The aim is to identify optimal design parameters and system configurations that enhance heat transfer efficiency while achieving a uniform impingement pressure distribution.These findings have practical implications for applications requiring efficient cooling.The optimized design achieved a 12.28%increase in convective heat transfer efficiency with a local Nusselt number of 113.05 compared to 100.69 in the reference design.Enhanced convective cooling and heat flux were observed in the optimized configuration,particularly in areas of direct jet impingement.Additionally,the optimized design maintained lower wall temperatures,demonstrating more effective thermal dissipation.
基金Project (2009ZX04005-031-11) supported by the National Major Science and Technology Special Program of ChinaProject ([2011]3008)supported by the State Foundation for Studying AbroadProject (B08040) supported by the 111 Project
