By using the dynamic shift-share analysis, the industrial structure and competitive strength of 31 provincial districts except Taiwan, Hong Kong and Macao are studied by taking the GDP of the three industries as the r...By using the dynamic shift-share analysis, the industrial structure and competitive strength of 31 provincial districts except Taiwan, Hong Kong and Macao are studied by taking the GDP of the three industries as the research entrance and the whole nation as the reference district. The industrial structure and competitive strength of each provincial district is measured. Through the analysis of pertinence, the correlation degree of industrial structure and industrial competitive strength to economic growth is analyzed. The results show that the industrial competitive strength is closely related to the economic growth of the 31 provincial districts, but the contribution made by the industrial structure to economic growth is insufficient and the effect of industrial structure does not match with that of industrial competitive strength. According to industrial competitiveness and industrial structure effect, 31 provincial districts of the whole nation are divided into 4 types and the relevant countermeasures of the four types are put forward.展开更多
Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emp...Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is required.This study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling equipment.The study specifically investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency stick-slip.These events not only hinder the efficiency of drilling but also lead to exhaustion and harm to the system’s components since they are difficult to be detected and controlled in real time.The study investigates the dynamic interactions of these vibrations,specifically in their high-frequency modes,usingfield data obtained from measurement while drilling.Thefindings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem performance.The obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control systems.Therefore,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect damage.Moreover,by exploiting thesefindings,the assessment of structural resilience in rotary drilling systems can be enhanced.Furthermore,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efficiency of rotary drilling systems in the petroleum industry.展开更多
Double-shaft-driven needle punching machine is a specialized equipment designed for processing C/C crucible preforms.Its main needle punching module is operated by two sets of reciprocating crank-slider mechanisms.The...Double-shaft-driven needle punching machine is a specialized equipment designed for processing C/C crucible preforms.Its main needle punching module is operated by two sets of reciprocating crank-slider mechanisms.The intense vibration during needle punching not only generates huge noise,but also substantially reduces the quality of the preform.It is imperative to perform a dynamic analysis and optimization of the entire needle punching machine.In this paper,the three-dimensional(3D)model of the entire double-shaft-driven needle punching machine for C/C crucible preforms is established.Based on the modal analysis theory,the modal characteristics of the needle punching machine under various operating conditions are analyzed and its natural frequencies and vibration modes are determined.The harmonic response analysis is then employed to obtain the amplitude of the needle plate at different frequencies,and the structural weak points of the needle punching machine are identified and improved.The feasibility of the optimized scheme is subsequently reevaluated and verified.The results indicate that the first six natural frequencies of the machine increase,and the maximum amplitude of the needle plate decreases by 70.3%.The enhanced dynamic characteristics of the machine significantly improve its performance,enabling more efficient needle punching of C/C crucible preforms.展开更多
The nonlinear Schrodinger equation(NLSE) is a key tool for modeling wave propagation in nonlinear and dispersive media. This study focuses on the complex cubic NLSE with δ-potential,explored through the Brownian proc...The nonlinear Schrodinger equation(NLSE) is a key tool for modeling wave propagation in nonlinear and dispersive media. This study focuses on the complex cubic NLSE with δ-potential,explored through the Brownian process. The investigation begins with the derivation of stochastic solitary wave solutions using the modified exp(-Ψ(ξ)) expansion method. To illustrate the noise effects, 3D and 2D visualizations are displayed for different non-negative values of noise parameter under suitable parameter values. Additionally, qualitative analysis of both perturbed and unperturbed dynamical systems is conducted using bifurcation and chaos theory. In bifurcation analysis, we analyze the detailed parameter analysis near fixed points of the unperturbed system. An external periodic force is applied to perturb the system, leading to an investigation of its chaotic behavior. Chaos detection tools are employed to predict the behavior of the perturbed dynamical system, with results validated through visual representations.Multistability analysis is conducted under varying initial conditions to identify multiple stable states in the perturbed dynamical system, contributing to chaotic behavior. Also, sensitivity analysis of the Hamiltonian system is performed for different initial conditions. The novelty of this work lies in the significance of the obtained results, which have not been previously explored for the considered equation. These findings offer noteworthy insights into the behavior of the complex cubic NLSE with δ-potential and its applications in fields such as nonlinear optics, quantum mechanics and Bose–Einstein condensates.展开更多
Assessing the benefits and costs of digitalization in the energy industry is a complex issue.Traditional cost-benefit analysis(CBA)might encounter problems in addressing uncertainties,dynamic stakeholder interactions,...Assessing the benefits and costs of digitalization in the energy industry is a complex issue.Traditional cost-benefit analysis(CBA)might encounter problems in addressing uncertainties,dynamic stakeholder interactions,and feedback loops arising out of the evolving nature of digitalization.This paper introduces a methodological framework to help address the intricate inter connections between digital applications and business models in the energy industry.The proposed framework leverages system dynamics to achieve two primary objectives.It investigates how digitalization generally influences the value proposi-tion,value capture,and value creation dimensions of business models.It also quantifies the financial and social impacts of digitalization from a dynamic perspective.The proposed dynamic CBA allows for a more precise quantification of the benefits and costs,associated with evidence-based decision-making.Findings from an illustrative case study challenge the static assumptions of conventional methods.These methods often presume continuous operation,neglecting reinvestment and operational feedback loops,and resulting in negative net present values.Conversely,the outcomes of the proposed method indicate positive net present values when accounting for factors such as reinvestment rates and the will-ingness to invest in digitalization projects.The principles outlined in this paper can enable a more accu-rate assessment of digitalization projects,thus catalyzing the development of new CBA applications and guidelines for digitalization.展开更多
During the construction of bank slopes involving pile driving,ensuring slope stability is crucial.This requires the design of appropriate support systems and a thorough evaluation of the failure mechanisms of pile str...During the construction of bank slopes involving pile driving,ensuring slope stability is crucial.This requires the design of appropriate support systems and a thorough evaluation of the failure mechanisms of pile structures under dynamic loading conditions.Based on the Huarong Coal Wharf project,various support schemes are analyzed using numerical simulation methods to calculate and compare slope stability coefficients.The optimal scheme is then identified.Under the selected support scheme,a numerical model of double-row suspended steel sheet piles is developed to investigate the dynamic response of the pile structures under pile driving loads.A time-history analysis is performed to assess the slope’s dynamic stability.The results show that the maximum displacements of the upper and lower steel sheet pile rows are 2.51 and 3.14 cm,respectively.The maximum principal stresses remain below 20 MPa in both rows,while the maximum von Mises stresses are 20.85 MPa for the upper row and 25.40 MPa for the lower row.The dominant frequencies of the steel sheet pile structures fall between 30 and 35 Hz,with a frequency bandwidth ranging from 0 to 500 Hz.The stability coefficient of the pile structures varies over time during the pile driving process,ultimately reaching a value of 1.26—exceeding the required safety threshold.This research provides practical guidance for designing support systems in wharf piling projects and offers a reliable basis for evaluating the safety performance of steel sheet piles in bank slopes.展开更多
In this paper,a meshfree Jacobi point interpolation(MJPI)approach for the dynamic analysis of sandwich laminated conical and cylindrical shells with varying thickness is presented.The theoretical formulations for sand...In this paper,a meshfree Jacobi point interpolation(MJPI)approach for the dynamic analysis of sandwich laminated conical and cylindrical shells with varying thickness is presented.The theoretical formulations for sandwich laminated shells with varying thickness are established using the modified variational principle within the framework of first-order shear deformation theory(FSDT).The displacement components of the sandwich shell are expanded using the MJPI shape function and Fourier series in the meridional and circumferential directions,respectively.The accuracy and reliability of the proposed MJPI shape function are validated against numerical results from published literature and the commercial simulation tool Abaqus.Finally,the effects of different parameters such as thickness gradient,thickness power index and boundary condition on the free vibration and dynamic response of the sandwich laminated shell are investigated.展开更多
Kernel-based slow feature analysis(SFA)methods have been successfully applied in the industrial process fault detection field.However,kernel-based SFA methods have high computational complexity as dealing with nonline...Kernel-based slow feature analysis(SFA)methods have been successfully applied in the industrial process fault detection field.However,kernel-based SFA methods have high computational complexity as dealing with nonlinearity,leading to delays in detecting time-varying data features.Additionally,the uncertain kernel function and kernel parameters limit the ability of the extracted features to express process characteristics,resulting in poor fault detection performance.To alleviate the above problems,a novel randomized auto-regressive dynamic slow feature analysis(RRDSFA)method is proposed to simultaneously monitor the operating point deviations and process dynamic faults,enabling real-time monitoring of data features in industrial processes.Firstly,the proposed Random Fourier mappingbased method achieves more effective nonlinear transformation,contrasting with the current kernelbased RDSFA algorithm that may lead to significant computational complexity.Secondly,a randomized RDSFA model is developed to extract nonlinear dynamic slow features.Furthermore,a Bayesian inference-based overall fault monitoring model including all RRDSFA sub-models is developed to overcome the randomness of random Fourier mapping.Finally,the superiority and effectiveness of the proposed monitoring method are demonstrated through a numerical case and a simulation of continuous stirred tank reactor.展开更多
Data-driven process monitoring is an effective approach to assure safe operation of modern manufacturing and energy systems,such as thermal power plants being studied in this work.Industrial processes are inherently d...Data-driven process monitoring is an effective approach to assure safe operation of modern manufacturing and energy systems,such as thermal power plants being studied in this work.Industrial processes are inherently dynamic and need to be monitored using dynamic algorithms.Mainstream dynamic algorithms rely on concatenating current measurement with past data.This work proposes a new,alternative dynamic process monitoring algorithm,using dot product feature analysis(DPFA).DPFA computes the dot product of consecutive samples,thus naturally capturing the process dynamics through temporal correlation.At the same time,DPFA's online computational complexity is lower than not just existing dynamic algorithms,but also classical static algorithms(e.g.,principal component analysis and slow feature analysis).The detectability of the new algorithm is analyzed for three types of faults typically seen in process systems:sensor bias,process fault and gain change fault.Through experiments with a numerical example and real data from a thermal power plant,the DPFA algorithm is shown to be superior to the state-of-the-art methods,in terms of better monitoring performance(fault detection rate and false alarm rate)and lower computational complexity.展开更多
This paper presents a framework for constructing surrogate models for sensitivity analysis of structural dynamics behavior.Physical models involving deformation,such as collisions,vibrations,and penetration,are devel-...This paper presents a framework for constructing surrogate models for sensitivity analysis of structural dynamics behavior.Physical models involving deformation,such as collisions,vibrations,and penetration,are devel-oped using the material point method.To reduce the computational cost of Monte Carlo simulations,response surface models are created as surrogate models for the material point system to approximate its dynamic behavior.An adaptive randomized greedy algorithm is employed to construct a sparse polynomial chaos expansion model with a fixed order,effectively balancing the accuracy and computational efficiency of the surrogate model.Based on the sparse polynomial chaos expansion,sensitivity analysis is conducted using the global finite difference and Sobol methods.Several examples of structural dynamics are provided to demonstrate the effectiveness of the proposed method in addressing structural dynamics problems.展开更多
Dynamic analysis of the tethered satellite system(TSS)can provide a fundamental guideline to the evaluation of performance and robust design of the system examined.Uncertainties inherited with the parameters would ind...Dynamic analysis of the tethered satellite system(TSS)can provide a fundamental guideline to the evaluation of performance and robust design of the system examined.Uncertainties inherited with the parameters would induce unexpected variation of the response and deteriorate the reliability of the system.In this work,the effect of uncertain mass of the satellites on the deployment and retrieval dynamics of the TSS is investigated.First the interval mode is employed to take the variation of mass of satellite into account in the processes of deployment and retrieval.Then,the Chebyshev interval method is used to obtain the lower and upper response bounds of the TSS.To achieve a smooth and reliable implementation of deployment and retrieval,the nonlinear programming based on the Gauss pseudospectral method is adopted to obtain optimal trajectory of tether velocity.Numerical results show that the uncertainties of mass of the satellites have a distinct influence on the response of tether tension in the processes of deployment and retrieval.展开更多
To address the mooring issues of floating photovoltaic systems in areas with large tidal variations,three mooring schemes were designed and compared in this paper:anchor chain,anchor chain with added weights,and ancho...To address the mooring issues of floating photovoltaic systems in areas with large tidal variations,three mooring schemes were designed and compared in this paper:anchor chain,anchor chain with added weights,and anchor chain with Superflex.The model was established via the numerical simulation tool Orcaflex,which considers the combined effects of wind,waves,and currents.A time-domain coupled dynamic analysis was conducted on the performance of the three mooring schemes under various tidal conditions to determine the mooring cable tension and platform motion response.Furthermore,the mooring system with an anchor chain and Superflex was optimized,with a focus on analyzing the effects of the Superflex length,the diameter of the anchor chains,and the mooring radius.The mooring system with the anchor chain and Superflex exhibits more controllable and stable mooring performance in areas with large tidal variations,so that it more effectively maintains the required mooring tension level.These findings not only provide a reference for the feasibility and optimization design of photovoltaic systems in areas with large tidal variations but also offer valuable experience for the sustainable application of clean energy under specific environmental conditions.展开更多
This paper delves into the dynamical analysis,chaos control,Mittag–Leffler boundedness(MLB),and forecasting a fractional-order financial risk(FOFR)system through an absolute function term.To this end,the FOFR system ...This paper delves into the dynamical analysis,chaos control,Mittag–Leffler boundedness(MLB),and forecasting a fractional-order financial risk(FOFR)system through an absolute function term.To this end,the FOFR system is first proposed,and the adomian decomposition method(ADM)is employed to resolve this fractional-order system.The stability of equilibrium points and the corresponding control schemes are assessed,and several classical tools such as Lyapunov exponents(LE),bifurcation diagrams,complexity analysis(CA),and 0–1 test are further extended to analyze the dynamical behaviors of FOFR.Then the global Mittag–Leffler attractive set(MLAS)and Mittag–Leffler positive invariant set(MLPIS)for the proposed financial risk(FR)system are discussed.Finally,a proficient reservoir-computing(RC)method is applied to forecast the temporal evolution of the complex dynamics for the proposed system,and some simulations are carried out to show the effectiveness and feasibility of the present scheme.展开更多
The power grid,as the hub connecting the power supply and consumption sides,plays an important role in achieving carbon neutrality in China.In emerging carbon markets,assessing the investment benefits of power-grid en...The power grid,as the hub connecting the power supply and consumption sides,plays an important role in achieving carbon neutrality in China.In emerging carbon markets,assessing the investment benefits of power-grid enterprises is essential.Thus,studying the impact of the carbon market on the investment and operation of powergrid enterprises is key to ensuring their efficient operation.Notably,few studies have examined the interaction between the carbon and electricity markets using system dynamics models,highlighting a research gap in this area.This study investigates the impact of the carbon market on the investment of power-grid enterprises using a novel evaluation system based on a system dynamics model that considers carbon-emissions from an established carbon-emission accounting model.First,an index system for benefit evaluation was constructed from six aspects:financing ability,economic benefit,reliability,social responsibility,user satisfaction,and carbon-emissions.A system dynamics model was then developed to reflect the causal feedback relationship between the impact of the carbon market on the investment and operation of power-grid enterprises.The simulation results of a provincial power-grid enterprise analyze comprehensive investment evaluation benefits over a 10-year period and the impact of carbon emissions on the investment and operation of power-grid enterprises.This study provides guidelines for the benign development of power-grid enterprises within the context of the carbon market.展开更多
The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of risers.This approach leads to...The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of risers.This approach leads to a challenging problem:coupling the dynamics of risers with a new hang-off system combined with multiple structures and complex constraints.To accurately analyze the dynamic responses of the coupled system,a coupled dynamic model is established based on the Euler-Bernoulli beam-column theory and penalty function method.A comprehensive analysis method is proposed for coupled dynamic analysis by combining the finite element method and the Newmarkβmethod.An analysis program is also developed in MATLAB for dynamic simulation.The simulation results show that the dynamic performances of the risers at the top part are significantly improved by the new hang-off system,especially the novel design,which includes the centralizer and articulation joint.The bending moment and lateral deformation of the risers at the top part decrease,while the hang-off joint experiences a great bending moment at the bottom of the lateral restraint area which requires particular attention in design and application.The platform navigation speed range under the safety limits of risers expands with the new hang-off system in use.展开更多
The axial single-pass high temperature compression test of a hot-rolled extra-large heavy H-beam steel continuous casting billet (Q420 steel) under different deformation conditions through the Gleeble-1500D thermomech...The axial single-pass high temperature compression test of a hot-rolled extra-large heavy H-beam steel continuous casting billet (Q420 steel) under different deformation conditions through the Gleeble-1500D thermomechanical simulator was carried out. The modified Johnson–Cook model and the Arrhenius model based on strain-compensated of Q420 steel were established. The latter can more accurately reflect the flow behavior of Q420 steel. For the simulation of thermal compression, dynamic recrystallization (DRX) correlation models were developed and imported into DEFORM-3D software. According to simulation results, high temperatures and low strain rates are conducive to DRX. Due to the uneven distribution of equivalent strain and temperature in different parts of the same section, DRX volume fraction and grain size are unevenly distributed. At the center, the DRX volume fraction is the largest and the grain size is the smallest. The upper and lower edges are vice versa, and the left and right edges are centered. Optical microscopy and electron backscatter diffraction characterization methods were used to study the hot compression microstructure under different deformation conditions. As the deformation amount increases, complete DRX is gradually reached. The original austenite grain gradually becomes smaller. Local average misorientation decreases with the progression of DRX but increases with the amount of deformation after completion of DRX. As the temperature increases and the rate decreases, low angle grain boundaries and medium angle grain boundaries gradually decrease, and high angle grain boundaries gradually increase, indicating that dislocation decreases gradually, DRX grains increase gradually, and martensitic multilayer structure is obvious. As austenite grain size increases, the length of martensite lath increases, and the number of martensite blocks decreases.展开更多
A rigorous analytical model is developed for simulating the vibration behaviors of large-diameter openended pipe piles(OEPPs)and surrounding soil undergoing high-strain impact loading.To describe the soil behavior,the...A rigorous analytical model is developed for simulating the vibration behaviors of large-diameter openended pipe piles(OEPPs)and surrounding soil undergoing high-strain impact loading.To describe the soil behavior,the soil along pile shaft is divided into slip and nonslip zones and the base soil is modeled as a fictitious-soil pile(FSP)to account for the wave propagation in the soil.True soil properties are adopted and slippage at the pile-soil interface is considered,allowing realistic representation of largediameter OEPP mechanics.The developed model is validated by comparing with conventional models and finite element method(FEM).It is further used to successfully simulate and interpret the behaviors of a steel OEPP during the offshore field test.It is found that the variation in the vertical vibrations of shaft soil along radial direction is significant for large-diameter OEPPs,and the velocity amplitudes of the internal and external soil attenuate following different patterns.The shaft soil motion may not attenuate with depth due to the soil slippage,while the wave attenuation at base soil indicates an influence depth,with a faster attenuation rate than that in the pile.The findings from the current study should aid in simulating the vibration behaviors of large-diameter OEPP-soil system under high-strain dynamic loading.展开更多
This study presents results from sentiment analysis of Dynamic message sign (DMS) message content, focusing on messages that include numbers of road fatalities. As a traffic management tool, DMS plays a role in influe...This study presents results from sentiment analysis of Dynamic message sign (DMS) message content, focusing on messages that include numbers of road fatalities. As a traffic management tool, DMS plays a role in influencing driver behavior and assisting transportation agencies in achieving safe and efficient traffic movement. However, the psychological and behavioral effects of displaying fatality numbers on DMS remain poorly understood;hence, it is important to know the potential impacts of displaying such messages. The Iowa Department of Transportation displays the number of fatalities on a first screen, followed by a supplemental message hoping to promote safe driving;an example is “19 TRAFFIC DEATHS THIS YEAR IF YOU HAVE A SUPER BOWL DON’T DRIVE HIGH.” We employ natural language processing to decode the sentiment and undertone of the supplementary message and investigate how they influence driving speeds. According to the results of a mixed effect model, drivers reduced speeds marginally upon encountering DMS fatality text with a positive sentiment with a neutral undertone. This category had the largest associated amount of speed reduction, while messages with negative sentiment with a negative undertone had the second largest amount of speed reduction, greater than other combinations, including positive sentiment with a positive undertone.展开更多
This paper reviews works on the dynamic analysis of flexible and rigid pavements under moving vehicles on the basis of continuum-based plane strain models and linear theories.The purpose of this review is to provide i...This paper reviews works on the dynamic analysis of flexible and rigid pavements under moving vehicles on the basis of continuum-based plane strain models and linear theories.The purpose of this review is to provide in-formation about the existing works on the subject,critically discuss them and make suggestions for further research.The reviewed papers are presented on the basis of the various models for pavement-vehicle systems and the various methods for dynamically analyzing these systems.Flexible pavements are modeled by a homogeneous or layered half-plane with isotropic or anisotropic and linear elastic,viscoelastic or poroelastic material behavior.Rigid pavements are modeled by a beam or plate on a homogeneous or layered half-plane with material properties like the ones for flexible pavements.The vehicles are modeled as concentrated or distributed over a finite area loads moving with constant or time dependent speed.The above pavement-vehicle models are dynamically analyzed by analytical,analytical/numerical or purely numerical methods working in the time or frequency domain.Representative examples are presented to illustrate the models and methods of analysis,demonstrate their merits and assess the effects of the various parameters on pavement response.The paper closes with con-clusions and suggestions for further research in the area.The significance of this research effort has to do with the presentation of the existing literature on the subject in a critical and easy to understand way with the aid of representative examples and the identification of new research areas.展开更多
The effectiveness of dual-doping as a method of improving the conductivity of sulfide solid electrolytes(SEs)is not in doubt;however,the atomic-level mechanisms underpinning these enhancements remain elusive.In this s...The effectiveness of dual-doping as a method of improving the conductivity of sulfide solid electrolytes(SEs)is not in doubt;however,the atomic-level mechanisms underpinning these enhancements remain elusive.In this study,we investigate the atomic mechanisms associated with the high ionic conductivity of the Li_(7)P_(3)S_(11)(LPS)SE and its response to Ag/Cl dual dopants.Synthesis and electrochemical characterizations show that the 0.2 M AgCl-doped LPS(Li_(6.8)P_(3)Ag_(0.1)S_(10.9)Cl_(0.1))exhibited an over 80%improvement in ionic conductivity compared with the undoped LPS.The atomic-level structures responsible for the enhanced conductivity were generated by a set of experiment and simulation techniques:synchrotron X-ray diffractometry,Rietveld refinement,density functional theory,and artificial neural network-based molecular dynamics simulations.This thorough characterization highlights the role of dual dopants in altering the structure and ionic conductivity.We found that the PS_(4) and P_(2)S_(7) structural motifs of LPS undergo transformation into various PS_(x) substructures.These changes in the substructures,in conjunction with the paddle-wheel effect,enable rapid Li migration.The dopant atoms serve to enhance the flexibility of PS_(4)–P_(2)S_(7) polyhedral frameworks,consequently enhancing the ionic conductivity.Our study elucidates a clear structure–conductivity relationship for the dual-doped LPS,providing a fundamental guideline for the development of sulfide SEs with superior conductivity.展开更多
文摘By using the dynamic shift-share analysis, the industrial structure and competitive strength of 31 provincial districts except Taiwan, Hong Kong and Macao are studied by taking the GDP of the three industries as the research entrance and the whole nation as the reference district. The industrial structure and competitive strength of each provincial district is measured. Through the analysis of pertinence, the correlation degree of industrial structure and industrial competitive strength to economic growth is analyzed. The results show that the industrial competitive strength is closely related to the economic growth of the 31 provincial districts, but the contribution made by the industrial structure to economic growth is insufficient and the effect of industrial structure does not match with that of industrial competitive strength. According to industrial competitiveness and industrial structure effect, 31 provincial districts of the whole nation are divided into 4 types and the relevant countermeasures of the four types are put forward.
文摘Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is required.This study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling equipment.The study specifically investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency stick-slip.These events not only hinder the efficiency of drilling but also lead to exhaustion and harm to the system’s components since they are difficult to be detected and controlled in real time.The study investigates the dynamic interactions of these vibrations,specifically in their high-frequency modes,usingfield data obtained from measurement while drilling.Thefindings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem performance.The obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control systems.Therefore,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect damage.Moreover,by exploiting thesefindings,the assessment of structural resilience in rotary drilling systems can be enhanced.Furthermore,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efficiency of rotary drilling systems in the petroleum industry.
基金Open Project of Shanghai Key Laboratory of Lightweight Composite,China(No.2232021A4-04)。
文摘Double-shaft-driven needle punching machine is a specialized equipment designed for processing C/C crucible preforms.Its main needle punching module is operated by two sets of reciprocating crank-slider mechanisms.The intense vibration during needle punching not only generates huge noise,but also substantially reduces the quality of the preform.It is imperative to perform a dynamic analysis and optimization of the entire needle punching machine.In this paper,the three-dimensional(3D)model of the entire double-shaft-driven needle punching machine for C/C crucible preforms is established.Based on the modal analysis theory,the modal characteristics of the needle punching machine under various operating conditions are analyzed and its natural frequencies and vibration modes are determined.The harmonic response analysis is then employed to obtain the amplitude of the needle plate at different frequencies,and the structural weak points of the needle punching machine are identified and improved.The feasibility of the optimized scheme is subsequently reevaluated and verified.The results indicate that the first six natural frequencies of the machine increase,and the maximum amplitude of the needle plate decreases by 70.3%.The enhanced dynamic characteristics of the machine significantly improve its performance,enabling more efficient needle punching of C/C crucible preforms.
基金Supporting Project under Grant No.RSP2025R472,King Saud University,Riyadh,Saudi Arabia。
文摘The nonlinear Schrodinger equation(NLSE) is a key tool for modeling wave propagation in nonlinear and dispersive media. This study focuses on the complex cubic NLSE with δ-potential,explored through the Brownian process. The investigation begins with the derivation of stochastic solitary wave solutions using the modified exp(-Ψ(ξ)) expansion method. To illustrate the noise effects, 3D and 2D visualizations are displayed for different non-negative values of noise parameter under suitable parameter values. Additionally, qualitative analysis of both perturbed and unperturbed dynamical systems is conducted using bifurcation and chaos theory. In bifurcation analysis, we analyze the detailed parameter analysis near fixed points of the unperturbed system. An external periodic force is applied to perturb the system, leading to an investigation of its chaotic behavior. Chaos detection tools are employed to predict the behavior of the perturbed dynamical system, with results validated through visual representations.Multistability analysis is conducted under varying initial conditions to identify multiple stable states in the perturbed dynamical system, contributing to chaotic behavior. Also, sensitivity analysis of the Hamiltonian system is performed for different initial conditions. The novelty of this work lies in the significance of the obtained results, which have not been previously explored for the considered equation. These findings offer noteworthy insights into the behavior of the complex cubic NLSE with δ-potential and its applications in fields such as nonlinear optics, quantum mechanics and Bose–Einstein condensates.
基金conducted as part of the project Innovative Tools for Cyber-Physical Energy Systems(InnoCyPES)received funding from the European Union’s Horizon 2020 research and innovation pro-gram under the Marie Skłodowska-Curie(956433).
文摘Assessing the benefits and costs of digitalization in the energy industry is a complex issue.Traditional cost-benefit analysis(CBA)might encounter problems in addressing uncertainties,dynamic stakeholder interactions,and feedback loops arising out of the evolving nature of digitalization.This paper introduces a methodological framework to help address the intricate inter connections between digital applications and business models in the energy industry.The proposed framework leverages system dynamics to achieve two primary objectives.It investigates how digitalization generally influences the value proposi-tion,value capture,and value creation dimensions of business models.It also quantifies the financial and social impacts of digitalization from a dynamic perspective.The proposed dynamic CBA allows for a more precise quantification of the benefits and costs,associated with evidence-based decision-making.Findings from an illustrative case study challenge the static assumptions of conventional methods.These methods often presume continuous operation,neglecting reinvestment and operational feedback loops,and resulting in negative net present values.Conversely,the outcomes of the proposed method indicate positive net present values when accounting for factors such as reinvestment rates and the will-ingness to invest in digitalization projects.The principles outlined in this paper can enable a more accu-rate assessment of digitalization projects,thus catalyzing the development of new CBA applications and guidelines for digitalization.
基金sponsored by Natural Science Research Project of Anhui Educational Committee(GrantNo.2022AH050810),NationalNatural Science Foundation of China(GrantNos.42402276,41972286,42072309,42102329)State Key Laboratory of Precision Blasting and Hubei Key Laboratory of Blasting Engineering,Jianghan University(No.PBSKL2023A1)the Open Fund of National Center for International Research on Deep Earth Drilling and Resource Development(No.DEDRD-2023-02).
文摘During the construction of bank slopes involving pile driving,ensuring slope stability is crucial.This requires the design of appropriate support systems and a thorough evaluation of the failure mechanisms of pile structures under dynamic loading conditions.Based on the Huarong Coal Wharf project,various support schemes are analyzed using numerical simulation methods to calculate and compare slope stability coefficients.The optimal scheme is then identified.Under the selected support scheme,a numerical model of double-row suspended steel sheet piles is developed to investigate the dynamic response of the pile structures under pile driving loads.A time-history analysis is performed to assess the slope’s dynamic stability.The results show that the maximum displacements of the upper and lower steel sheet pile rows are 2.51 and 3.14 cm,respectively.The maximum principal stresses remain below 20 MPa in both rows,while the maximum von Mises stresses are 20.85 MPa for the upper row and 25.40 MPa for the lower row.The dominant frequencies of the steel sheet pile structures fall between 30 and 35 Hz,with a frequency bandwidth ranging from 0 to 500 Hz.The stability coefficient of the pile structures varies over time during the pile driving process,ultimately reaching a value of 1.26—exceeding the required safety threshold.This research provides practical guidance for designing support systems in wharf piling projects and offers a reliable basis for evaluating the safety performance of steel sheet piles in bank slopes.
文摘In this paper,a meshfree Jacobi point interpolation(MJPI)approach for the dynamic analysis of sandwich laminated conical and cylindrical shells with varying thickness is presented.The theoretical formulations for sandwich laminated shells with varying thickness are established using the modified variational principle within the framework of first-order shear deformation theory(FSDT).The displacement components of the sandwich shell are expanded using the MJPI shape function and Fourier series in the meridional and circumferential directions,respectively.The accuracy and reliability of the proposed MJPI shape function are validated against numerical results from published literature and the commercial simulation tool Abaqus.Finally,the effects of different parameters such as thickness gradient,thickness power index and boundary condition on the free vibration and dynamic response of the sandwich laminated shell are investigated.
基金supported by the Program of National Natural Science Foundation of China(U23A20329,62163036)Youth Academic and Technical Leaders Reserve Talent Training project(202105AC160094)Industrial Innovation Talent Special Project of Xingdian Talent Support Program(XDYC-CYCX-2022-0010).
文摘Kernel-based slow feature analysis(SFA)methods have been successfully applied in the industrial process fault detection field.However,kernel-based SFA methods have high computational complexity as dealing with nonlinearity,leading to delays in detecting time-varying data features.Additionally,the uncertain kernel function and kernel parameters limit the ability of the extracted features to express process characteristics,resulting in poor fault detection performance.To alleviate the above problems,a novel randomized auto-regressive dynamic slow feature analysis(RRDSFA)method is proposed to simultaneously monitor the operating point deviations and process dynamic faults,enabling real-time monitoring of data features in industrial processes.Firstly,the proposed Random Fourier mappingbased method achieves more effective nonlinear transformation,contrasting with the current kernelbased RDSFA algorithm that may lead to significant computational complexity.Secondly,a randomized RDSFA model is developed to extract nonlinear dynamic slow features.Furthermore,a Bayesian inference-based overall fault monitoring model including all RRDSFA sub-models is developed to overcome the randomness of random Fourier mapping.Finally,the superiority and effectiveness of the proposed monitoring method are demonstrated through a numerical case and a simulation of continuous stirred tank reactor.
基金supported in part by the National Science Fund for Distinguished Young Scholars of China(62225303)the National Natural Science Fundation of China(62303039,62433004)+2 种基金the China Postdoctoral Science Foundation(BX20230034,2023M730190)the Fundamental Research Funds for the Central Universities(buctrc202201,QNTD2023-01)the High Performance Computing Platform,College of Information Science and Technology,Beijing University of Chemical Technology
文摘Data-driven process monitoring is an effective approach to assure safe operation of modern manufacturing and energy systems,such as thermal power plants being studied in this work.Industrial processes are inherently dynamic and need to be monitored using dynamic algorithms.Mainstream dynamic algorithms rely on concatenating current measurement with past data.This work proposes a new,alternative dynamic process monitoring algorithm,using dot product feature analysis(DPFA).DPFA computes the dot product of consecutive samples,thus naturally capturing the process dynamics through temporal correlation.At the same time,DPFA's online computational complexity is lower than not just existing dynamic algorithms,but also classical static algorithms(e.g.,principal component analysis and slow feature analysis).The detectability of the new algorithm is analyzed for three types of faults typically seen in process systems:sensor bias,process fault and gain change fault.Through experiments with a numerical example and real data from a thermal power plant,the DPFA algorithm is shown to be superior to the state-of-the-art methods,in terms of better monitoring performance(fault detection rate and false alarm rate)and lower computational complexity.
基金support from the National Natural Science Foundation of China(Grant Nos.52174123&52274222).
文摘This paper presents a framework for constructing surrogate models for sensitivity analysis of structural dynamics behavior.Physical models involving deformation,such as collisions,vibrations,and penetration,are devel-oped using the material point method.To reduce the computational cost of Monte Carlo simulations,response surface models are created as surrogate models for the material point system to approximate its dynamic behavior.An adaptive randomized greedy algorithm is employed to construct a sparse polynomial chaos expansion model with a fixed order,effectively balancing the accuracy and computational efficiency of the surrogate model.Based on the sparse polynomial chaos expansion,sensitivity analysis is conducted using the global finite difference and Sobol methods.Several examples of structural dynamics are provided to demonstrate the effectiveness of the proposed method in addressing structural dynamics problems.
基金supported by the National Natural Science Foundation of China(Grant No.U21B2075)。
文摘Dynamic analysis of the tethered satellite system(TSS)can provide a fundamental guideline to the evaluation of performance and robust design of the system examined.Uncertainties inherited with the parameters would induce unexpected variation of the response and deteriorate the reliability of the system.In this work,the effect of uncertain mass of the satellites on the deployment and retrieval dynamics of the TSS is investigated.First the interval mode is employed to take the variation of mass of satellite into account in the processes of deployment and retrieval.Then,the Chebyshev interval method is used to obtain the lower and upper response bounds of the TSS.To achieve a smooth and reliable implementation of deployment and retrieval,the nonlinear programming based on the Gauss pseudospectral method is adopted to obtain optimal trajectory of tether velocity.Numerical results show that the uncertainties of mass of the satellites have a distinct influence on the response of tether tension in the processes of deployment and retrieval.
基金financially supported by the National Key R&D Program of China(Grant No.2022YFB4200700).
文摘To address the mooring issues of floating photovoltaic systems in areas with large tidal variations,three mooring schemes were designed and compared in this paper:anchor chain,anchor chain with added weights,and anchor chain with Superflex.The model was established via the numerical simulation tool Orcaflex,which considers the combined effects of wind,waves,and currents.A time-domain coupled dynamic analysis was conducted on the performance of the three mooring schemes under various tidal conditions to determine the mooring cable tension and platform motion response.Furthermore,the mooring system with an anchor chain and Superflex was optimized,with a focus on analyzing the effects of the Superflex length,the diameter of the anchor chains,and the mooring radius.The mooring system with the anchor chain and Superflex exhibits more controllable and stable mooring performance in areas with large tidal variations,so that it more effectively maintains the required mooring tension level.These findings not only provide a reference for the feasibility and optimization design of photovoltaic systems in areas with large tidal variations but also offer valuable experience for the sustainable application of clean energy under specific environmental conditions.
基金Project jointly supported by the National Natural Science Foundation of China(Grant No.12372013)Program for Science and Technology Innovation Talents in Universities of Henan Province,China(Grant No.24HASTIT034)+3 种基金the Natural Science Foundation of Henan Province,China(Grant No.232300420122)the Humanities and Society Science Foundation from the Ministry of Education of China(Grant No.19YJCZH265)China Postdoctoral Science Foundation(Grant No.2019M651633)First Class Discipline of Zhejiang-A(Zhejiang University of Finance and Economics Statistics),the Collaborative Innovation Center for Data Science and Big Data Analysis(Zhejiang University of Finance and Economics-Statistics).
文摘This paper delves into the dynamical analysis,chaos control,Mittag–Leffler boundedness(MLB),and forecasting a fractional-order financial risk(FOFR)system through an absolute function term.To this end,the FOFR system is first proposed,and the adomian decomposition method(ADM)is employed to resolve this fractional-order system.The stability of equilibrium points and the corresponding control schemes are assessed,and several classical tools such as Lyapunov exponents(LE),bifurcation diagrams,complexity analysis(CA),and 0–1 test are further extended to analyze the dynamical behaviors of FOFR.Then the global Mittag–Leffler attractive set(MLAS)and Mittag–Leffler positive invariant set(MLPIS)for the proposed financial risk(FR)system are discussed.Finally,a proficient reservoir-computing(RC)method is applied to forecast the temporal evolution of the complex dynamics for the proposed system,and some simulations are carried out to show the effectiveness and feasibility of the present scheme.
基金supported by the National Natural Science Foundation of China(Grant No.52107087).
文摘The power grid,as the hub connecting the power supply and consumption sides,plays an important role in achieving carbon neutrality in China.In emerging carbon markets,assessing the investment benefits of power-grid enterprises is essential.Thus,studying the impact of the carbon market on the investment and operation of powergrid enterprises is key to ensuring their efficient operation.Notably,few studies have examined the interaction between the carbon and electricity markets using system dynamics models,highlighting a research gap in this area.This study investigates the impact of the carbon market on the investment of power-grid enterprises using a novel evaluation system based on a system dynamics model that considers carbon-emissions from an established carbon-emission accounting model.First,an index system for benefit evaluation was constructed from six aspects:financing ability,economic benefit,reliability,social responsibility,user satisfaction,and carbon-emissions.A system dynamics model was then developed to reflect the causal feedback relationship between the impact of the carbon market on the investment and operation of power-grid enterprises.The simulation results of a provincial power-grid enterprise analyze comprehensive investment evaluation benefits over a 10-year period and the impact of carbon emissions on the investment and operation of power-grid enterprises.This study provides guidelines for the benign development of power-grid enterprises within the context of the carbon market.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52271300,52071337,and 51809279)the National Key Research and Development Program of China(Grant No.2022YFC2806501)the High-tech Ship Research Projects Sponsored by MIIT(Grant No.CBG2N21-4-2-5).
文摘The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of risers.This approach leads to a challenging problem:coupling the dynamics of risers with a new hang-off system combined with multiple structures and complex constraints.To accurately analyze the dynamic responses of the coupled system,a coupled dynamic model is established based on the Euler-Bernoulli beam-column theory and penalty function method.A comprehensive analysis method is proposed for coupled dynamic analysis by combining the finite element method and the Newmarkβmethod.An analysis program is also developed in MATLAB for dynamic simulation.The simulation results show that the dynamic performances of the risers at the top part are significantly improved by the new hang-off system,especially the novel design,which includes the centralizer and articulation joint.The bending moment and lateral deformation of the risers at the top part decrease,while the hang-off joint experiences a great bending moment at the bottom of the lateral restraint area which requires particular attention in design and application.The platform navigation speed range under the safety limits of risers expands with the new hang-off system in use.
基金supported by Topic 3 of the 14th Five-Year National Key Research and Development Plan:Prediction and Control Technology for Hot Rolling Shape-Performance Integration of Ultra Large Size H-beam Steel(Project No.2021YFB3401003).
文摘The axial single-pass high temperature compression test of a hot-rolled extra-large heavy H-beam steel continuous casting billet (Q420 steel) under different deformation conditions through the Gleeble-1500D thermomechanical simulator was carried out. The modified Johnson–Cook model and the Arrhenius model based on strain-compensated of Q420 steel were established. The latter can more accurately reflect the flow behavior of Q420 steel. For the simulation of thermal compression, dynamic recrystallization (DRX) correlation models were developed and imported into DEFORM-3D software. According to simulation results, high temperatures and low strain rates are conducive to DRX. Due to the uneven distribution of equivalent strain and temperature in different parts of the same section, DRX volume fraction and grain size are unevenly distributed. At the center, the DRX volume fraction is the largest and the grain size is the smallest. The upper and lower edges are vice versa, and the left and right edges are centered. Optical microscopy and electron backscatter diffraction characterization methods were used to study the hot compression microstructure under different deformation conditions. As the deformation amount increases, complete DRX is gradually reached. The original austenite grain gradually becomes smaller. Local average misorientation decreases with the progression of DRX but increases with the amount of deformation after completion of DRX. As the temperature increases and the rate decreases, low angle grain boundaries and medium angle grain boundaries gradually decrease, and high angle grain boundaries gradually increase, indicating that dislocation decreases gradually, DRX grains increase gradually, and martensitic multilayer structure is obvious. As austenite grain size increases, the length of martensite lath increases, and the number of martensite blocks decreases.
基金support from the Exploring Youth Project of Zhejiang Natural Science Foundation (Grant No.LQ24E080009)the Key Project of Natural Science Foundation of Zhejiang Province (Grant No.LXZ22E080001)the National Natural Science Foundation of China (Grant No.52108347).
文摘A rigorous analytical model is developed for simulating the vibration behaviors of large-diameter openended pipe piles(OEPPs)and surrounding soil undergoing high-strain impact loading.To describe the soil behavior,the soil along pile shaft is divided into slip and nonslip zones and the base soil is modeled as a fictitious-soil pile(FSP)to account for the wave propagation in the soil.True soil properties are adopted and slippage at the pile-soil interface is considered,allowing realistic representation of largediameter OEPP mechanics.The developed model is validated by comparing with conventional models and finite element method(FEM).It is further used to successfully simulate and interpret the behaviors of a steel OEPP during the offshore field test.It is found that the variation in the vertical vibrations of shaft soil along radial direction is significant for large-diameter OEPPs,and the velocity amplitudes of the internal and external soil attenuate following different patterns.The shaft soil motion may not attenuate with depth due to the soil slippage,while the wave attenuation at base soil indicates an influence depth,with a faster attenuation rate than that in the pile.The findings from the current study should aid in simulating the vibration behaviors of large-diameter OEPP-soil system under high-strain dynamic loading.
文摘This study presents results from sentiment analysis of Dynamic message sign (DMS) message content, focusing on messages that include numbers of road fatalities. As a traffic management tool, DMS plays a role in influencing driver behavior and assisting transportation agencies in achieving safe and efficient traffic movement. However, the psychological and behavioral effects of displaying fatality numbers on DMS remain poorly understood;hence, it is important to know the potential impacts of displaying such messages. The Iowa Department of Transportation displays the number of fatalities on a first screen, followed by a supplemental message hoping to promote safe driving;an example is “19 TRAFFIC DEATHS THIS YEAR IF YOU HAVE A SUPER BOWL DON’T DRIVE HIGH.” We employ natural language processing to decode the sentiment and undertone of the supplementary message and investigate how they influence driving speeds. According to the results of a mixed effect model, drivers reduced speeds marginally upon encountering DMS fatality text with a positive sentiment with a neutral undertone. This category had the largest associated amount of speed reduction, while messages with negative sentiment with a negative undertone had the second largest amount of speed reduction, greater than other combinations, including positive sentiment with a positive undertone.
文摘This paper reviews works on the dynamic analysis of flexible and rigid pavements under moving vehicles on the basis of continuum-based plane strain models and linear theories.The purpose of this review is to provide in-formation about the existing works on the subject,critically discuss them and make suggestions for further research.The reviewed papers are presented on the basis of the various models for pavement-vehicle systems and the various methods for dynamically analyzing these systems.Flexible pavements are modeled by a homogeneous or layered half-plane with isotropic or anisotropic and linear elastic,viscoelastic or poroelastic material behavior.Rigid pavements are modeled by a beam or plate on a homogeneous or layered half-plane with material properties like the ones for flexible pavements.The vehicles are modeled as concentrated or distributed over a finite area loads moving with constant or time dependent speed.The above pavement-vehicle models are dynamically analyzed by analytical,analytical/numerical or purely numerical methods working in the time or frequency domain.Representative examples are presented to illustrate the models and methods of analysis,demonstrate their merits and assess the effects of the various parameters on pavement response.The paper closes with con-clusions and suggestions for further research in the area.The significance of this research effort has to do with the presentation of the existing literature on the subject in a critical and easy to understand way with the aid of representative examples and the identification of new research areas.
基金National Research Foundation of Korea,Grant/A ward Numbers:MEST,NRF-2021R1A2C2009596Engineeringand Physical Sciences Research Council,Grant/A ward Numbers:EP/R029431,EP/P020194,EP/T022213+1 种基金Korea government(Ministry of Science and ICT,MSIT),Grant/Award Number:RS-2023-00236572European Research Council,ERC,Grant/Award Numbers:EP/R029431,EP/P020194,EP/T022213。
文摘The effectiveness of dual-doping as a method of improving the conductivity of sulfide solid electrolytes(SEs)is not in doubt;however,the atomic-level mechanisms underpinning these enhancements remain elusive.In this study,we investigate the atomic mechanisms associated with the high ionic conductivity of the Li_(7)P_(3)S_(11)(LPS)SE and its response to Ag/Cl dual dopants.Synthesis and electrochemical characterizations show that the 0.2 M AgCl-doped LPS(Li_(6.8)P_(3)Ag_(0.1)S_(10.9)Cl_(0.1))exhibited an over 80%improvement in ionic conductivity compared with the undoped LPS.The atomic-level structures responsible for the enhanced conductivity were generated by a set of experiment and simulation techniques:synchrotron X-ray diffractometry,Rietveld refinement,density functional theory,and artificial neural network-based molecular dynamics simulations.This thorough characterization highlights the role of dual dopants in altering the structure and ionic conductivity.We found that the PS_(4) and P_(2)S_(7) structural motifs of LPS undergo transformation into various PS_(x) substructures.These changes in the substructures,in conjunction with the paddle-wheel effect,enable rapid Li migration.The dopant atoms serve to enhance the flexibility of PS_(4)–P_(2)S_(7) polyhedral frameworks,consequently enhancing the ionic conductivity.Our study elucidates a clear structure–conductivity relationship for the dual-doped LPS,providing a fundamental guideline for the development of sulfide SEs with superior conductivity.
