Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network cap...Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network capacity degradations. In this paper, a mixed stochastic user equilibrium model was proposed to describe the interactive route choice behaviors between ATIS equipped and unequipped drivers on a degradable transport network. In the proposed model the information accessibility of equipped drivers was reflected by lower degree of uncertainty in their stochastic equilibrium flow distributions, and their behavioral adaptability was captured by multiple equilibrium behaviors over the stochastic network state set. The mixed equilibrium model was formulated as a fixed point problem defined in the mixed route flows, and its solution was achieved by executing an iterative algorithm. Numerical experiments were provided to verify the properties of the mixed network equilibrium model and the efficiency of the iterative algorithm.展开更多
Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,an...Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,and defects behind the structure.To address the need for rapid detection of different defect types,the current state of rapid detection technologies and equipment,both domestically and internationally,is systematically reviewed.The research reveals that surface defect detection technologies and equipment have developed rapidly in recent years.Notably,the integration of machine vision and laser scanning technologies have significantly improved detection efficiency and accuracy,achieving crack detection precision of up to 0.1 mm.However,the non-contact rapid detection of internal and behind-the-structure defects remains constrained by hardware limitations,with traditional detection remaining dominant.Nevertheless,phased array radar,ultrasonic,and acoustic vibration detection technologies have become research hotspots in recent years,offering promising directions for detecting these challenging defect types.Additionally,the application of multisensor fusion technology in rapid detection equipment has further enhanced detection capabilities.Devices such as cameras,3D laser scanners,infrared thermal imagers,and radar demonstrate significant advantages in rapid detection.Future research in tunnel inspection should prioritize breakthroughs in rapid detection technologies for internal and behind-the-structure defects.Efforts should also focus on developing multifunctional integrated detection vehicles that can simultaneously inspect both surface and internal structures.Furthermore,progress in fully automated,intelligent systems with precise defect identification and real-time reporting will be essential to significantly improve the efficiency and accuracy of tunnel inspection.展开更多
Phosphate is the main limiting factor of water eutrophication. In order to effectively control phosphorus pollution in water, straw microwave charcoal(CaCl2SBC) was prepared with straw after CaCl2activation and microw...Phosphate is the main limiting factor of water eutrophication. In order to effectively control phosphorus pollution in water, straw microwave charcoal(CaCl2SBC) was prepared with straw after CaCl2activation and microwave biomass carbonization, and the adsorption effect of phosphate by CaCl2SBC was analyzed. The results showed that the prepared straw microwave charcoal contained hydroxyl and carbon-carbon double bonds, and CaCl2SBC had a very obvious adsorption effect on phosphate in eutrophic water. The optimum conditions for the adsorption of phosphate by CaCl2SBC are as follows: initial concentration of phosphate was 50 mg/L;adsorption time was 120 min;pH was 9;adsorption temperature was 25 ℃;CaCl2SBC dosage was 300 mg/L. Under the optimum conditions, the maximum removal rate can reach 99%. The prepared straw microwave charcoal can be used for phosphorus removal from eutrophic water.展开更多
Engineering ethics is generated from the research on ethical issues caused by engineering activities. The development of engineering ethics in China was compared with that of European countries and the United States. ...Engineering ethics is generated from the research on ethical issues caused by engineering activities. The development of engineering ethics in China was compared with that of European countries and the United States. Problems such as non-standard evaluation of registered engineers,weak ethical awareness,and lack of scientific understanding in engineering activities were discussed. Establishing and improving the system of registered engineers,strengthening education in engineering ethics,and promoting public participation will be the only way for the development of engineering ethics in China.展开更多
To shorten the existing box culvert demolition construction period and ensure the normal operation of the railway, the jacking-out construction method was adopted. The ABAQUS finite element software was used to establ...To shorten the existing box culvert demolition construction period and ensure the normal operation of the railway, the jacking-out construction method was adopted. The ABAQUS finite element software was used to establish a three-dimensional model of the box culvert and soil body of the relying project, and three excavation thickness (0m, 1 m, 2 m) were used as the main variation parameters for numerical analysis and research, and the change law of the box culvert itself and soil body stress during the culvert jacking out process was obtained. The results show that the jacking force-displacement curves of the three working conditions can be divided into two stages, and the jacking force reaches the maximum value at the moment when the static friction turns into sliding friction at the end of the first stage. The stress distribution at the bottom slab of the box culvert in the jacking process is approximately normal, and the stress decreases with the increase of the roadbed excavation thickness. The increase of the roadbed excavation thickness can reduce the soil pressure on the side of the box culvert and effectively reduce the deformation of the roadbed in the jacking-out process. The deformation of the roadbed during the jacking process can be reduced by increasing the thickness of the roadbed excavation.展开更多
Purpose–This paper aims to study the influence of aerodynamics force of trains passing each other on the dynamic response of vehicle bridge coupling system based on numerical simulation and multi-body dynamics and pu...Purpose–This paper aims to study the influence of aerodynamics force of trains passing each other on the dynamic response of vehicle bridge coupling system based on numerical simulation and multi-body dynamics and put forward the speed threshold for safe running of train under different crosswind speeds.Design/methodology/approach–The computational fluid dynamics method is adopted to simulate the aerodynamic force in the whole process of train passing each other by using dynamic grid technology.The dynamic model of vehicle-bridge coupling system is established considering the effects of aerodynamic force of train passing each other under crosswind,the dynamic response of train intersection on the bridge under crosswind is computed and the running safety of the train is evaluated.Findings–The aerodynamic force of trains’intersection has little effects on the derailment factor,lateral wheel-rail force and vertical acceleration of train,but it increases the offload factor of train and significantly increases the lateral acceleration of train.The crosswind has a significant effect on increasing the derailment factor,lateral wheel-rail force and offload factor of train.The offload factor of train is the key factor to control the threshold of train speed.The impact of the aerodynamic force of trains’intersection on running safety cannot be ignored.When the extreme values of crosswind wind speed are 15 m$s1,20 m$s1 and 25 m$s1,respectively,the corresponding speed thresholds for safe running of train are 350 km$h1,275 km$h1 and 200 km$h1,respectively.Originality/value–The research can provide a more precise numerical method to study the running safety of high-speed trains under the aerodynamic effect of trains passing each other on bridge in crosswind.展开更多
The multi-piped freezing method is usually applied in artificial ground freezing （AGF） projects to fulfill special construction requirements, such as two-, three-, or four-piped freezing. Based on potential superpos...The multi-piped freezing method is usually applied in artificial ground freezing （AGF） projects to fulfill special construction requirements, such as two-, three-, or four-piped freezing. Based on potential superposition theory, this paper gives analytical solutions to steady-state frozen temperature for two, three, and four freezing pipes with different temperatures and arranged at random. Specific solutions are derived for some particular arrangements, such as three freezing pipes in a linear arrangement with equal or unequal spacing, right and isosceles triangle arrangements, four freezing pipes in a linear arrangement with equal spacing, and rhombus and rectangle arrangements. A comparison between the analytical solutions and numerical thermal analysis shows that the analytical solutions are sufficiently precise. As a part of the theory of AGF, the analytical solutions of temperature fields for multi-piped freezing with arbitrary layouts and different temperatures of freezing pipes are approached for the first time.展开更多
The fatigue flexural performance of RC beams attacked by salt spray was studied. A testing method involving electro osmosis, electrical accelerated corrosion and salt spray was proposed. This corrosion process method ...The fatigue flexural performance of RC beams attacked by salt spray was studied. A testing method involving electro osmosis, electrical accelerated corrosion and salt spray was proposed. This corrosion process method effectively simulates real-world salt spray and fatigue loading exerted by RC components on sea bridges. Four RC beams that have different stress amplitudes were tested. It is found that deterioration by corrosion and fatigue loading reduces the fatigue life of the RC and decreases the ability of deformation. The fatigue life and deflection ability could be reduced by increasing the stress amplitude and the corrosion duration time. The test result demonstrates that this experimental method can couple corrosion deterioration and fatigue loading reasonably. This procedure may be applied to evaluate the fatigue life and concrete durability of RC components located in a natural salt spray environment.展开更多
Traffic prediction already plays a significant role in applications like traffic planning and urban management,but it is still difficult to capture the highly non-linear and complicated spatiotemporal correlations of ...Traffic prediction already plays a significant role in applications like traffic planning and urban management,but it is still difficult to capture the highly non-linear and complicated spatiotemporal correlations of traffic data.As well as to fulfil both long-termand short-termprediction objectives,a better representation of the temporal dependency and global spatial correlation of traffic data is needed.In order to do this,the Spatiotemporal Graph Neural Network(S-GNN)is proposed in this research as amethod for traffic prediction.The S-GNN simultaneously accepts various traffic data as inputs and investigates the non-linear correlations between the variables.In terms of modelling,the road network is initially represented as a spatiotemporal directed graph,with the features of the samples at the time step being captured by a convolution module.In order to assign varying attention weights to various adjacent area nodes of the target node,the adjacent areas information of nodes in the road network is then aggregated using a graph network.The data is output using a fully connected layer at the end.The findings show that S-GNN can improve short-and long-term traffic prediction accuracy to a greater extent;in comparison to the control model,the RMSE of S-GNN is reduced by about 0.571 to 9.288 and the MAE(Mean Absolute Error)by about 0.314 to 7.678.The experimental results on two real datasets,Pe MSD7(M)and PEMS-BAY,also support this claim.展开更多
In the paper,the analytic static deflection solutions of uniform cantilever beams resting on nonlinear elastic rotational boundary are developed by the Modified Adomian Decomposition Method(MADM).If the applied force ...In the paper,the analytic static deflection solutions of uniform cantilever beams resting on nonlinear elastic rotational boundary are developed by the Modified Adomian Decomposition Method(MADM).If the applied force function is an analytic function,then the deflection function can be derived and expressed in Maclaurin series.A recurrence relation for the coefficients of the Maclaurin series is derived.It is shown that the proposed solution method is accurate and efficient.The solution method can be successfully applied to the uniform cantilever beam and non-linear elastic rotational boundary problem.展开更多
Cement stabilized materials(CSM)are widely used in pavement base layers,where fatigue damage is inevitable throughout their service life.Due to their significant heterogeneity as multiphase composite materials,a multi...Cement stabilized materials(CSM)are widely used in pavement base layers,where fatigue damage is inevitable throughout their service life.Due to their significant heterogeneity as multiphase composite materials,a multi-scale approach is essential for studying their fatigue damage.This paper aims to propose a combined approach of simulations and measurements.This approach can characterize the multiphase and heterogeneity properties of CSM and reveal their fatigue damage rules.Firstly,the strength and fatigue performance of CSM were tested,leading to the development of a macroscopic modulus fatigue damage model.Secondly,a pre-and post-fatigue test X-ray computed tomography method with maintained loading was developed to capture the internal meso-structure of CSM.The trainable Weka segmentation was used to provide an accurate meso-structure of CSM for discrete element model(DEM).Thirdly,microscopic testing results were utilized to calibrate the contact parameters of the DEM.The virtually generated aggregate methods for DEM were proposed to enrich the specimens.Finally,virtual fatigue tests were conducted to investigate the fatigue damage rules and to extend the macroscopic modulus fatigue damage model.The results revealed that the fatigue damage rules of CSM accumulate nonlinearly.From a macroscopic perspective,the decay in modulus follows an Scurve across three stages.From a mesoscopic perspective,the average radius coefficient of DEM bonded contacts decreases at an accelerating decay rate.The method proposed in this study reveals the fatigue damage rules under varying stress ratios and cement contents,and develops a simulation based fatigue life prediction equation of CSM.This study offers a reliable numerical technique for modeling and analyzing the fatigue damage rules of composite materials.展开更多
Recently,Internet ofThings(IoT)has been increasingly integrated into the automotive sector,enabling the development of diverse applications such as the Internet of Vehicles(IoV)and intelligent connected vehicles.Lever...Recently,Internet ofThings(IoT)has been increasingly integrated into the automotive sector,enabling the development of diverse applications such as the Internet of Vehicles(IoV)and intelligent connected vehicles.Leveraging IoVtechnologies,operational data fromcore vehicle components can be collected and analyzed to construct fault diagnosis models,thereby enhancing vehicle safety.However,automakers often struggle to acquire sufficient fault data to support effective model training.To address this challenge,a robust and efficient federated learning method(REFL)is constructed for machinery fault diagnosis in collaborative IoV,which can organize multiple companies to collaboratively develop a comprehensive fault diagnosis model while keeping their data locally.In the REFL,the gradient-based adversary algorithm is first introduced to the fault diagnosis field to enhance the deep learning model robustness.Moreover,the adaptive gradient processing process is designed to improve the model training speed and ensure the model accuracy under unbalance data scenarios.The proposed REFL is evaluated on non-independent and identically distributed(non-IID)real-world machinery fault dataset.Experiment results demonstrate that the REFL can achieve better performance than traditional learning methods and are promising for real industrial fault diagnosis.展开更多
Let B(E,F) be the set of all bounded linear operators from a Banach space E into another Banach space F,B^+(E, F) the set of all double splitting operators in B(E, F)and GI(A) the set of generalized inverses of A ∈ B...Let B(E,F) be the set of all bounded linear operators from a Banach space E into another Banach space F,B^+(E, F) the set of all double splitting operators in B(E, F)and GI(A) the set of generalized inverses of A ∈ B^+(E, F). In this paper we introduce an unbounded domain ?(A, A^+) in B(E, F) for A ∈ B^+(E, F) and A^+∈GI(A), and provide a necessary and sufficient condition for T ∈ ?(A, A^+). Then several conditions equivalent to the following property are proved: B = A+(IF+(T-A)A^+)^(-1) is the generalized inverse of T with R(B)=R(A^+) and N(B)=N(A^+), for T∈?(A, A^+), where IF is the identity on F. Also we obtain the smooth(C~∞) diffeomorphism M_A(A^+,T) from ?(A,A^+) onto itself with the fixed point A. Let S = {T ∈ ?(A, A^+) : R(T)∩ N(A^+) ={0}}, M(X) = {T ∈ B(E,F) : TN(X) ? R(X)} for X ∈ B(E,F)}, and F = {M(X) : ?X ∈B(E, F)}. Using the diffeomorphism M_A(A^+,T) we prove the following theorem: S is a smooth submanifold in B(E,F) and tangent to M(X) at any X ∈ S. The theorem expands the smooth integrability of F at A from a local neighborhoold at A to the global unbounded domain ?(A, A^+). It seems to be useful for developing global analysis and geomatrical method in differential equations.展开更多
Improving the cracking resistance of steel-normal concrete(NC)composite beams in the negative moment region is one of the main tasks in designing continuous composite beam(CCB)bridges due to the low tensile strength o...Improving the cracking resistance of steel-normal concrete(NC)composite beams in the negative moment region is one of the main tasks in designing continuous composite beam(CCB)bridges due to the low tensile strength of the NC deck at pier supports.This study proposed an innovative structural configuration for the negative bending moment region in a steel-concrete CCB bridge with the aid of ultrahigh performance concrete(UHPC)layer.In order to investigate the feasibility and effectiveness of this new UHPC jointed structure in the negative bending moment region,field load testing was conducted on a newly built full-scale bridge.The newly designed structural configuration was described in detail regarding the structural characteristics(cracking resistance,economy,durability,and constructability).In the field investigation,strains on the surface of the concrete bridge deck,rebar,and steel beam in the negative bending moment region,as well as mid-span deflection,were measured under different load cases.Also,a finite element model for the four-span superstructure of the full-scale bridge was established and validated by the field test results.The simulated results in terms of strains and mid-span deflection showed moderate consistency with the test results.This field test and the finite element model results demonstrated that the new configuration with the UHPC layer provided an effective alternative for the negative bending moment region of the composite beam.展开更多
In this work,the effects of carbon nanotubes(CNTs)on the microstructure evolution,thermal conductivity,and mechanical properties of C_(f)/SiC composites during chemical vapor infiltration(CVI)densification were invest...In this work,the effects of carbon nanotubes(CNTs)on the microstructure evolution,thermal conductivity,and mechanical properties of C_(f)/SiC composites during chemical vapor infiltration(CVI)densification were investigated in detail.Compared with composites without CNTs,the thermal conductivity,flexural strength,flexural modulus,fracture toughness,interfacial shear strength,and proportional limit stress of specimens with CNTs of 4.94 wt%were improved by 117%,21.8%,67.4%,10.3%,36.4%,and 71.1%,respectively.This improvement was attributed to the role of CNTs in the division of inter-layer pores,which provided abundant vapor growth sites for the ceramic matrix and promoted densification of the whole composite.In addition,the high thermal conductivity network formed by the overlap of CNTs and the rivet strengthening effect of CNTs were beneficial for synergistic improvement of thermal conductivity and mechanical properties of the composites.Therefore,this study has practical significance for the development of thermal protection composite components with enhanced thermal conductivity and mechanical characteristics.展开更多
To improve the adaptability of Connected and Automated Vehicles(CAVs)in mixed traffic,this study proposes a prediction model training indicator that comprehensively considers drivers'Social Value Orientation(SVO)a...To improve the adaptability of Connected and Automated Vehicles(CAVs)in mixed traffic,this study proposes a prediction model training indicator that comprehensively considers drivers'Social Value Orientation(SVO)and planning goals.Active Influence Factor(AIF)is used as the goal to predict the future safety loss and consistency loss of CAVs.Second,an objective function based on SVO is constructed to understand the driver’s characteristics to evaluate the safety,comfort,efficiency,and consistency of candidate trajectories.The results showed that integrating SVO and consistency functions can help ensure that CAVs drive under a more stable risk potential energy field.The prediction planning model that considers SVO can improve the reliability of the CAV output trajectory to a certain extent.The prediction planning under the AIF has better accuracy and stability of the output trajectory;however,it still has strong adaptability and superiority under different sensitivity parameters.The minimum and maximum standard deviations of our model are 0.78 and 0.78 m,respectively,whereas the minimum and maximum standard deviations of the comparative model reach 2.07 and 4.56 m,respectively.The minimum standard deviation of the other comparative model reaches 1.35 m,and the maximum standard deviation reaches 4.45 m.展开更多
In this paper, we introduce the concepts of generalized regular points and narrow spectrum points of bounded linear operators on Hilbert spaces. The concept of generalized regular points is an extension of the concept...In this paper, we introduce the concepts of generalized regular points and narrow spectrum points of bounded linear operators on Hilbert spaces. The concept of generalized regular points is an extension of the concept regular points, and so, the set of all spectrum points is reduced to the narrow spectrum. We present not only the same and different properties of spectrum and of narrow spectrum but also show the relationship between them. Finally, the well known problem about the invariant subspaces of bounded linear operators on separable Hilbert spaces is simplified to the problem of the operator with narrow spectrum only.展开更多
As an essential part of modern smart manufacturing,road transport with large and heavy trucks has in-creased dramatically.Due to the inside wheel difference in the process of turning,there is a considerable safety haz...As an essential part of modern smart manufacturing,road transport with large and heavy trucks has in-creased dramatically.Due to the inside wheel difference in the process of turning,there is a considerable safety hazard in the blind area of the inside wheel difference.In this paper,multiple cameras combined with deep learning algorithms are introduced to detect pedestrians in the blind area of wheel error.A scheme of vehicle-pedestrian safety alarm detection system is developed via the integration of YOLOv5 and an improved binocular distance measurement method.The system accurately measures the distance between the truck and nearby pedestrians by utilizing multiple cameras and PP Human recognition,providing real-time safety alerts.The experimental results show that this method significantly reduces distance measurement errors,improves the reliability of pedestrian detection,achieves high accuracy and real-time performance,and thus enhances the safety of trucks in complex traffic environments.展开更多
Vast amounts of valuable historical tunnelling site investigation data remain underutilized due to inefficient content-based archiving and searching tools.This study introduces a novel data-driven framework that integ...Vast amounts of valuable historical tunnelling site investigation data remain underutilized due to inefficient content-based archiving and searching tools.This study introduces a novel data-driven framework that integrates transfer learning with reverse image search to revolutionize the utilization of historical data in tunnelling projects.The method indexes excavated tunnel sections with corresponding tunnel face images and identifies similarities between projects based on geological features.Transfer learning with pre-trained deep learning models is employed to compress tunnel face images into compact,lower-dimensional vectors,enabling efficient similarity searches.This transformation converts geological information into comparable vectors,enhancing the efficiency and speed of data searches.An online cloud service is developed to allow engineers to access similar historical projects in real-time.To enhance the quality of the compressed vectors,this study developed a multi-level feature extraction method.This method markedly improves the deep learning models’ability to accurately identify major features from rock images.When applied to a diverse range of tunnel excavation projects in China,the model exhibited an impressive accuracy of over 90%in retrieving projects with similar geological features.This underscores the model’s potential as a robust tool for enhancing data management and decision-making in tunnelling engineering.展开更多
Let E, F be two Banach spaces, B(E, F),B +(E, F), Φ(E, F), SΦ(E, F) and R(E, F) be bounded linear, double splitting, Fredholm, semi-Frdholm and finite rank operators from E into F, respectively. Let Σ be any one of...Let E, F be two Banach spaces, B(E, F),B +(E, F), Φ(E, F), SΦ(E, F) and R(E, F) be bounded linear, double splitting, Fredholm, semi-Frdholm and finite rank operators from E into F, respectively. Let Σ be any one of the following sets: {T ∈ Φ(E, F): Index T = constant and dim N(T) = constant}, {T ∈ SΦ(E, F): either dim N(T) =constant< ∞ or codim R(T) =constant< ∞} and {T ∈ R(E, F): Rank T =constant< ∞}. Then it is known that gS is a smooth submanifold of B(E, F) with the tangent space T A Σ = {B ∈ B(E, F): BN(A) ? R(A)} for any A ∈ Σ. However, for B*(E, F) = {T ∈ B +(E, F): dimN(T) = codimR(T) = ∞} without the characteristic numbers, dimN(A), codimR(A), index(A) and Rank(A) of the equivalent classes above, it is very difficult to find which class of operators in B*(E, E) forms a smooth submanifold of B(E, F). Fortunately, we find that B*(E, F) is just a smooth submanifold of B(E, F) with the tangent space T A B*(E, F) = {T ∈ B(E, F): TN(A) ? R(A)} for each A ∈ B*(E, F). Thus the geometric construction of B +(E, F) is obtained, i.e., B +(E, F) is a smooth Banach submanifold of B(E, F), which is the union of the previous smooth submanifolds disjoint from each other. Meanwhile we give a smooth submanifold S(A) of B(E, F), modeled on a fixed Banach space and containing A for any A ∈ B +(E, F). To end these, results on the generalized inverse perturbation analysis are generalized. Specially, in the case E = F = ? n , it is obtained that the set Σ r of all n × n matrices A with Rank(A) = r < n is an arcwise connected and smooth hypersurface (submanifold) in B(? n ) with dimΣ r = 2nr × r 2. Then a new geometrical construction of B(? n ), analogous to B +(E, F), is given besides its analysis and algebra constructions known well.展开更多
基金Projects(51378119,51578150)supported by the National Natural Science Foundation of China
文摘Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network capacity degradations. In this paper, a mixed stochastic user equilibrium model was proposed to describe the interactive route choice behaviors between ATIS equipped and unequipped drivers on a degradable transport network. In the proposed model the information accessibility of equipped drivers was reflected by lower degree of uncertainty in their stochastic equilibrium flow distributions, and their behavioral adaptability was captured by multiple equilibrium behaviors over the stochastic network state set. The mixed equilibrium model was formulated as a fixed point problem defined in the mixed route flows, and its solution was achieved by executing an iterative algorithm. Numerical experiments were provided to verify the properties of the mixed network equilibrium model and the efficiency of the iterative algorithm.
文摘Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,and defects behind the structure.To address the need for rapid detection of different defect types,the current state of rapid detection technologies and equipment,both domestically and internationally,is systematically reviewed.The research reveals that surface defect detection technologies and equipment have developed rapidly in recent years.Notably,the integration of machine vision and laser scanning technologies have significantly improved detection efficiency and accuracy,achieving crack detection precision of up to 0.1 mm.However,the non-contact rapid detection of internal and behind-the-structure defects remains constrained by hardware limitations,with traditional detection remaining dominant.Nevertheless,phased array radar,ultrasonic,and acoustic vibration detection technologies have become research hotspots in recent years,offering promising directions for detecting these challenging defect types.Additionally,the application of multisensor fusion technology in rapid detection equipment has further enhanced detection capabilities.Devices such as cameras,3D laser scanners,infrared thermal imagers,and radar demonstrate significant advantages in rapid detection.Future research in tunnel inspection should prioritize breakthroughs in rapid detection technologies for internal and behind-the-structure defects.Efforts should also focus on developing multifunctional integrated detection vehicles that can simultaneously inspect both surface and internal structures.Furthermore,progress in fully automated,intelligent systems with precise defect identification and real-time reporting will be essential to significantly improve the efficiency and accuracy of tunnel inspection.
基金Supported by the High-quality Ecological Restoration of Damaged Water BodyVocational Education Personnel Training and Education and Teaching Reform Research Project of Sichuan Provincial Department of Education during2022-2024 (GZJG2022-014)Education and Teaching Research Project of Chengdu Textile College in 2022 (2022cdfzjj19)。
文摘Phosphate is the main limiting factor of water eutrophication. In order to effectively control phosphorus pollution in water, straw microwave charcoal(CaCl2SBC) was prepared with straw after CaCl2activation and microwave biomass carbonization, and the adsorption effect of phosphate by CaCl2SBC was analyzed. The results showed that the prepared straw microwave charcoal contained hydroxyl and carbon-carbon double bonds, and CaCl2SBC had a very obvious adsorption effect on phosphate in eutrophic water. The optimum conditions for the adsorption of phosphate by CaCl2SBC are as follows: initial concentration of phosphate was 50 mg/L;adsorption time was 120 min;pH was 9;adsorption temperature was 25 ℃;CaCl2SBC dosage was 300 mg/L. Under the optimum conditions, the maximum removal rate can reach 99%. The prepared straw microwave charcoal can be used for phosphorus removal from eutrophic water.
文摘Engineering ethics is generated from the research on ethical issues caused by engineering activities. The development of engineering ethics in China was compared with that of European countries and the United States. Problems such as non-standard evaluation of registered engineers,weak ethical awareness,and lack of scientific understanding in engineering activities were discussed. Establishing and improving the system of registered engineers,strengthening education in engineering ethics,and promoting public participation will be the only way for the development of engineering ethics in China.
文摘To shorten the existing box culvert demolition construction period and ensure the normal operation of the railway, the jacking-out construction method was adopted. The ABAQUS finite element software was used to establish a three-dimensional model of the box culvert and soil body of the relying project, and three excavation thickness (0m, 1 m, 2 m) were used as the main variation parameters for numerical analysis and research, and the change law of the box culvert itself and soil body stress during the culvert jacking out process was obtained. The results show that the jacking force-displacement curves of the three working conditions can be divided into two stages, and the jacking force reaches the maximum value at the moment when the static friction turns into sliding friction at the end of the first stage. The stress distribution at the bottom slab of the box culvert in the jacking process is approximately normal, and the stress decreases with the increase of the roadbed excavation thickness. The increase of the roadbed excavation thickness can reduce the soil pressure on the side of the box culvert and effectively reduce the deformation of the roadbed in the jacking-out process. The deformation of the roadbed during the jacking process can be reduced by increasing the thickness of the roadbed excavation.
基金supported by the National Natural Science Foundation of China(Project no.52078489)and the Fundamental Research Funds for the Central Universities of Central South University(Project no.2021zzts0772)to which the authors are most grateful.
文摘Purpose–This paper aims to study the influence of aerodynamics force of trains passing each other on the dynamic response of vehicle bridge coupling system based on numerical simulation and multi-body dynamics and put forward the speed threshold for safe running of train under different crosswind speeds.Design/methodology/approach–The computational fluid dynamics method is adopted to simulate the aerodynamic force in the whole process of train passing each other by using dynamic grid technology.The dynamic model of vehicle-bridge coupling system is established considering the effects of aerodynamic force of train passing each other under crosswind,the dynamic response of train intersection on the bridge under crosswind is computed and the running safety of the train is evaluated.Findings–The aerodynamic force of trains’intersection has little effects on the derailment factor,lateral wheel-rail force and vertical acceleration of train,but it increases the offload factor of train and significantly increases the lateral acceleration of train.The crosswind has a significant effect on increasing the derailment factor,lateral wheel-rail force and offload factor of train.The offload factor of train is the key factor to control the threshold of train speed.The impact of the aerodynamic force of trains’intersection on running safety cannot be ignored.When the extreme values of crosswind wind speed are 15 m$s1,20 m$s1 and 25 m$s1,respectively,the corresponding speed thresholds for safe running of train are 350 km$h1,275 km$h1 and 200 km$h1,respectively.Originality/value–The research can provide a more precise numerical method to study the running safety of high-speed trains under the aerodynamic effect of trains passing each other on bridge in crosswind.
基金Project supported by the National Natural Science Foundation of China （Nos. 51178336 and 51478340）, the Natural Science Foundation of Zhejiang Province, China （No. LZ13E080002）, and the China Ministry of Communications Construction Science ＆ Technology Projects （No. 2013318R11300）
文摘The multi-piped freezing method is usually applied in artificial ground freezing （AGF） projects to fulfill special construction requirements, such as two-, three-, or four-piped freezing. Based on potential superposition theory, this paper gives analytical solutions to steady-state frozen temperature for two, three, and four freezing pipes with different temperatures and arranged at random. Specific solutions are derived for some particular arrangements, such as three freezing pipes in a linear arrangement with equal or unequal spacing, right and isosceles triangle arrangements, four freezing pipes in a linear arrangement with equal spacing, and rhombus and rectangle arrangements. A comparison between the analytical solutions and numerical thermal analysis shows that the analytical solutions are sufficiently precise. As a part of the theory of AGF, the analytical solutions of temperature fields for multi-piped freezing with arbitrary layouts and different temperatures of freezing pipes are approached for the first time.
文摘The fatigue flexural performance of RC beams attacked by salt spray was studied. A testing method involving electro osmosis, electrical accelerated corrosion and salt spray was proposed. This corrosion process method effectively simulates real-world salt spray and fatigue loading exerted by RC components on sea bridges. Four RC beams that have different stress amplitudes were tested. It is found that deterioration by corrosion and fatigue loading reduces the fatigue life of the RC and decreases the ability of deformation. The fatigue life and deflection ability could be reduced by increasing the stress amplitude and the corrosion duration time. The test result demonstrates that this experimental method can couple corrosion deterioration and fatigue loading reasonably. This procedure may be applied to evaluate the fatigue life and concrete durability of RC components located in a natural salt spray environment.
基金supported by Science and Technology Plan Project of Zhejiang Provincial Department of Transportation“Research and System Development of Highway Asset Digitalization Technology inUse Based onHigh-PrecisionMap”(Project Number:202203)in part by Science and Technology Plan Project of Zhejiang Provincial Department of Transportation:Research and Demonstration Application of Key Technologies for Precise Sensing of Expressway Thrown Objects(No.202204).
文摘Traffic prediction already plays a significant role in applications like traffic planning and urban management,but it is still difficult to capture the highly non-linear and complicated spatiotemporal correlations of traffic data.As well as to fulfil both long-termand short-termprediction objectives,a better representation of the temporal dependency and global spatial correlation of traffic data is needed.In order to do this,the Spatiotemporal Graph Neural Network(S-GNN)is proposed in this research as amethod for traffic prediction.The S-GNN simultaneously accepts various traffic data as inputs and investigates the non-linear correlations between the variables.In terms of modelling,the road network is initially represented as a spatiotemporal directed graph,with the features of the samples at the time step being captured by a convolution module.In order to assign varying attention weights to various adjacent area nodes of the target node,the adjacent areas information of nodes in the road network is then aggregated using a graph network.The data is output using a fully connected layer at the end.The findings show that S-GNN can improve short-and long-term traffic prediction accuracy to a greater extent;in comparison to the control model,the RMSE of S-GNN is reduced by about 0.571 to 9.288 and the MAE(Mean Absolute Error)by about 0.314 to 7.678.The experimental results on two real datasets,Pe MSD7(M)and PEMS-BAY,also support this claim.
文摘In the paper,the analytic static deflection solutions of uniform cantilever beams resting on nonlinear elastic rotational boundary are developed by the Modified Adomian Decomposition Method(MADM).If the applied force function is an analytic function,then the deflection function can be derived and expressed in Maclaurin series.A recurrence relation for the coefficients of the Maclaurin series is derived.It is shown that the proposed solution method is accurate and efficient.The solution method can be successfully applied to the uniform cantilever beam and non-linear elastic rotational boundary problem.
基金supported in part by the National Natural Science Foundation of China(grant No.52108395 and No.52478435)key project supported by the Joint Funds of the National Natural Science Foundation of China(grant No.U2433210)+1 种基金Innovation Capability Support Program of Shaanxi(grant No.2024RS-CXTD-43)Shaanxi Provincial Key Research and Development Project(grant No.2024GX-YBXM528)。
文摘Cement stabilized materials(CSM)are widely used in pavement base layers,where fatigue damage is inevitable throughout their service life.Due to their significant heterogeneity as multiphase composite materials,a multi-scale approach is essential for studying their fatigue damage.This paper aims to propose a combined approach of simulations and measurements.This approach can characterize the multiphase and heterogeneity properties of CSM and reveal their fatigue damage rules.Firstly,the strength and fatigue performance of CSM were tested,leading to the development of a macroscopic modulus fatigue damage model.Secondly,a pre-and post-fatigue test X-ray computed tomography method with maintained loading was developed to capture the internal meso-structure of CSM.The trainable Weka segmentation was used to provide an accurate meso-structure of CSM for discrete element model(DEM).Thirdly,microscopic testing results were utilized to calibrate the contact parameters of the DEM.The virtually generated aggregate methods for DEM were proposed to enrich the specimens.Finally,virtual fatigue tests were conducted to investigate the fatigue damage rules and to extend the macroscopic modulus fatigue damage model.The results revealed that the fatigue damage rules of CSM accumulate nonlinearly.From a macroscopic perspective,the decay in modulus follows an Scurve across three stages.From a mesoscopic perspective,the average radius coefficient of DEM bonded contacts decreases at an accelerating decay rate.The method proposed in this study reveals the fatigue damage rules under varying stress ratios and cement contents,and develops a simulation based fatigue life prediction equation of CSM.This study offers a reliable numerical technique for modeling and analyzing the fatigue damage rules of composite materials.
基金supported in part by National key R&D projects(2024YFB4207203)National Natural Science Foundation of China(52401376)+3 种基金the Zhejiang Provincial Natural Science Foundation of China under Grant(No.LTGG24F030004)Hangzhou Key Scientific Research Plan Project(2024SZD1A24)“Pioneer”and“Leading Goose”R&DProgramof Zhejiang(2024C03254,2023C03154)Jiangxi Provincial Gan-Po Elite Support Program(Major Academic and Technical Leaders Cultivation Project,20243BCE51180).
文摘Recently,Internet ofThings(IoT)has been increasingly integrated into the automotive sector,enabling the development of diverse applications such as the Internet of Vehicles(IoV)and intelligent connected vehicles.Leveraging IoVtechnologies,operational data fromcore vehicle components can be collected and analyzed to construct fault diagnosis models,thereby enhancing vehicle safety.However,automakers often struggle to acquire sufficient fault data to support effective model training.To address this challenge,a robust and efficient federated learning method(REFL)is constructed for machinery fault diagnosis in collaborative IoV,which can organize multiple companies to collaboratively develop a comprehensive fault diagnosis model while keeping their data locally.In the REFL,the gradient-based adversary algorithm is first introduced to the fault diagnosis field to enhance the deep learning model robustness.Moreover,the adaptive gradient processing process is designed to improve the model training speed and ensure the model accuracy under unbalance data scenarios.The proposed REFL is evaluated on non-independent and identically distributed(non-IID)real-world machinery fault dataset.Experiment results demonstrate that the REFL can achieve better performance than traditional learning methods and are promising for real industrial fault diagnosis.
文摘Let B(E,F) be the set of all bounded linear operators from a Banach space E into another Banach space F,B^+(E, F) the set of all double splitting operators in B(E, F)and GI(A) the set of generalized inverses of A ∈ B^+(E, F). In this paper we introduce an unbounded domain ?(A, A^+) in B(E, F) for A ∈ B^+(E, F) and A^+∈GI(A), and provide a necessary and sufficient condition for T ∈ ?(A, A^+). Then several conditions equivalent to the following property are proved: B = A+(IF+(T-A)A^+)^(-1) is the generalized inverse of T with R(B)=R(A^+) and N(B)=N(A^+), for T∈?(A, A^+), where IF is the identity on F. Also we obtain the smooth(C~∞) diffeomorphism M_A(A^+,T) from ?(A,A^+) onto itself with the fixed point A. Let S = {T ∈ ?(A, A^+) : R(T)∩ N(A^+) ={0}}, M(X) = {T ∈ B(E,F) : TN(X) ? R(X)} for X ∈ B(E,F)}, and F = {M(X) : ?X ∈B(E, F)}. Using the diffeomorphism M_A(A^+,T) we prove the following theorem: S is a smooth submanifold in B(E,F) and tangent to M(X) at any X ∈ S. The theorem expands the smooth integrability of F at A from a local neighborhoold at A to the global unbounded domain ?(A, A^+). It seems to be useful for developing global analysis and geomatrical method in differential equations.
基金The authors would like to acknowledge the following funders for their support to the studies in this paper:the National Key R&D Program of China(No.2018YFC0705406)the National Natural Science Foundation of China(Grant No.51778223)+1 种基金the Major Program of Science and Technology of Hunan Province(No.2017SK1010)the Hunan Provincial Innovation Foundation for Postgraduate(No.CX2017B119).
文摘Improving the cracking resistance of steel-normal concrete(NC)composite beams in the negative moment region is one of the main tasks in designing continuous composite beam(CCB)bridges due to the low tensile strength of the NC deck at pier supports.This study proposed an innovative structural configuration for the negative bending moment region in a steel-concrete CCB bridge with the aid of ultrahigh performance concrete(UHPC)layer.In order to investigate the feasibility and effectiveness of this new UHPC jointed structure in the negative bending moment region,field load testing was conducted on a newly built full-scale bridge.The newly designed structural configuration was described in detail regarding the structural characteristics(cracking resistance,economy,durability,and constructability).In the field investigation,strains on the surface of the concrete bridge deck,rebar,and steel beam in the negative bending moment region,as well as mid-span deflection,were measured under different load cases.Also,a finite element model for the four-span superstructure of the full-scale bridge was established and validated by the field test results.The simulated results in terms of strains and mid-span deflection showed moderate consistency with the test results.This field test and the finite element model results demonstrated that the new configuration with the UHPC layer provided an effective alternative for the negative bending moment region of the composite beam.
基金supported by the National Natural Science Foundation of China(Grant Nos.52072304,51872229,and 52172100)the 111 Project of China(Grant No.B08040)+2 种基金Science Center for Gas Turbine Project(Grant No.P2022-B-IV-002-001)Key Research and Development Program of Shaanxi(Grant Nos.2022GY-367 and 2022GY-370)the Open Fund of Zhejiang Provincial Key Laboratory for Cutting Tools(Grant No.ZD202108).
文摘In this work,the effects of carbon nanotubes(CNTs)on the microstructure evolution,thermal conductivity,and mechanical properties of C_(f)/SiC composites during chemical vapor infiltration(CVI)densification were investigated in detail.Compared with composites without CNTs,the thermal conductivity,flexural strength,flexural modulus,fracture toughness,interfacial shear strength,and proportional limit stress of specimens with CNTs of 4.94 wt%were improved by 117%,21.8%,67.4%,10.3%,36.4%,and 71.1%,respectively.This improvement was attributed to the role of CNTs in the division of inter-layer pores,which provided abundant vapor growth sites for the ceramic matrix and promoted densification of the whole composite.In addition,the high thermal conductivity network formed by the overlap of CNTs and the rivet strengthening effect of CNTs were beneficial for synergistic improvement of thermal conductivity and mechanical properties of the composites.Therefore,this study has practical significance for the development of thermal protection composite components with enhanced thermal conductivity and mechanical characteristics.
基金supported by the Science and Technology Plan of Zhejiang Provincial Department of Transportation(Grant No.2024017)the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(Grant No.2022C01050)+4 种基金the Fundamental Research Funds for the Central Universities(Grant No.2024BSSXM01)the National Natural Science Foundation of China(Grant No.72361137006)the Natural Science Foundation of Zhejiang Province(Grant No.LR23E080002)the Research Project of Balanced Building Research Center,Zhejiang University(Grant No.K20212792)the Research Grants Council of the Hong Kong Special Administrative Region,China(Grant No.15210620).
文摘To improve the adaptability of Connected and Automated Vehicles(CAVs)in mixed traffic,this study proposes a prediction model training indicator that comprehensively considers drivers'Social Value Orientation(SVO)and planning goals.Active Influence Factor(AIF)is used as the goal to predict the future safety loss and consistency loss of CAVs.Second,an objective function based on SVO is constructed to understand the driver’s characteristics to evaluate the safety,comfort,efficiency,and consistency of candidate trajectories.The results showed that integrating SVO and consistency functions can help ensure that CAVs drive under a more stable risk potential energy field.The prediction planning model that considers SVO can improve the reliability of the CAV output trajectory to a certain extent.The prediction planning under the AIF has better accuracy and stability of the output trajectory;however,it still has strong adaptability and superiority under different sensitivity parameters.The minimum and maximum standard deviations of our model are 0.78 and 0.78 m,respectively,whereas the minimum and maximum standard deviations of the comparative model reach 2.07 and 4.56 m,respectively.The minimum standard deviation of the other comparative model reaches 1.35 m,and the maximum standard deviation reaches 4.45 m.
基金Supported by National Natural Science Foundation of China (Grant No. 11071051)Youth Science Foundation of Heilongjiang Province (Grant No. QC2009C73)the State Committee for Scientific Research of Poland (Grant No. N N201 362236)
文摘In this paper, we introduce the concepts of generalized regular points and narrow spectrum points of bounded linear operators on Hilbert spaces. The concept of generalized regular points is an extension of the concept regular points, and so, the set of all spectrum points is reduced to the narrow spectrum. We present not only the same and different properties of spectrum and of narrow spectrum but also show the relationship between them. Finally, the well known problem about the invariant subspaces of bounded linear operators on separable Hilbert spaces is simplified to the problem of the operator with narrow spectrum only.
基金funded by the science and technology Project of Zhejiang Province under Grant No.2023C35088.
文摘As an essential part of modern smart manufacturing,road transport with large and heavy trucks has in-creased dramatically.Due to the inside wheel difference in the process of turning,there is a considerable safety hazard in the blind area of the inside wheel difference.In this paper,multiple cameras combined with deep learning algorithms are introduced to detect pedestrians in the blind area of wheel error.A scheme of vehicle-pedestrian safety alarm detection system is developed via the integration of YOLOv5 and an improved binocular distance measurement method.The system accurately measures the distance between the truck and nearby pedestrians by utilizing multiple cameras and PP Human recognition,providing real-time safety alerts.The experimental results show that this method significantly reduces distance measurement errors,improves the reliability of pedestrian detection,achieves high accuracy and real-time performance,and thus enhances the safety of trucks in complex traffic environments.
基金funded by the Research and Development Program of the Department of Transportation Zhejiang,China(Grant No.202213)Australian Government through the Australian Research Council’s Discovery Projects funding scheme(Project No.DP220103381)+1 种基金the National Natural Science Foundation of China(Grant Nos.52222905,52179103 and 42272326)Jiangxi Provincial Natural Science Foundation(Grant Nos.20232ACB204031 and 20224ACB204019).
文摘Vast amounts of valuable historical tunnelling site investigation data remain underutilized due to inefficient content-based archiving and searching tools.This study introduces a novel data-driven framework that integrates transfer learning with reverse image search to revolutionize the utilization of historical data in tunnelling projects.The method indexes excavated tunnel sections with corresponding tunnel face images and identifies similarities between projects based on geological features.Transfer learning with pre-trained deep learning models is employed to compress tunnel face images into compact,lower-dimensional vectors,enabling efficient similarity searches.This transformation converts geological information into comparable vectors,enhancing the efficiency and speed of data searches.An online cloud service is developed to allow engineers to access similar historical projects in real-time.To enhance the quality of the compressed vectors,this study developed a multi-level feature extraction method.This method markedly improves the deep learning models’ability to accurately identify major features from rock images.When applied to a diverse range of tunnel excavation projects in China,the model exhibited an impressive accuracy of over 90%in retrieving projects with similar geological features.This underscores the model’s potential as a robust tool for enhancing data management and decision-making in tunnelling engineering.
基金supported by National Natural Science Foundation of China (Grant No.10771101,10671049)
文摘Let E, F be two Banach spaces, B(E, F),B +(E, F), Φ(E, F), SΦ(E, F) and R(E, F) be bounded linear, double splitting, Fredholm, semi-Frdholm and finite rank operators from E into F, respectively. Let Σ be any one of the following sets: {T ∈ Φ(E, F): Index T = constant and dim N(T) = constant}, {T ∈ SΦ(E, F): either dim N(T) =constant< ∞ or codim R(T) =constant< ∞} and {T ∈ R(E, F): Rank T =constant< ∞}. Then it is known that gS is a smooth submanifold of B(E, F) with the tangent space T A Σ = {B ∈ B(E, F): BN(A) ? R(A)} for any A ∈ Σ. However, for B*(E, F) = {T ∈ B +(E, F): dimN(T) = codimR(T) = ∞} without the characteristic numbers, dimN(A), codimR(A), index(A) and Rank(A) of the equivalent classes above, it is very difficult to find which class of operators in B*(E, E) forms a smooth submanifold of B(E, F). Fortunately, we find that B*(E, F) is just a smooth submanifold of B(E, F) with the tangent space T A B*(E, F) = {T ∈ B(E, F): TN(A) ? R(A)} for each A ∈ B*(E, F). Thus the geometric construction of B +(E, F) is obtained, i.e., B +(E, F) is a smooth Banach submanifold of B(E, F), which is the union of the previous smooth submanifolds disjoint from each other. Meanwhile we give a smooth submanifold S(A) of B(E, F), modeled on a fixed Banach space and containing A for any A ∈ B +(E, F). To end these, results on the generalized inverse perturbation analysis are generalized. Specially, in the case E = F = ? n , it is obtained that the set Σ r of all n × n matrices A with Rank(A) = r < n is an arcwise connected and smooth hypersurface (submanifold) in B(? n ) with dimΣ r = 2nr × r 2. Then a new geometrical construction of B(? n ), analogous to B +(E, F), is given besides its analysis and algebra constructions known well.
