In power production,gas turbines are commonly used components that generate high amount of energy depending on size and weight.They function as integral parts of helicopters,aircrafts,trains,ships,electrical generator...In power production,gas turbines are commonly used components that generate high amount of energy depending on size and weight.They function as integral parts of helicopters,aircrafts,trains,ships,electrical generators,and tanks.Notably,many researchers are focusing on the design,operation,and maintenance of gas turbines.The focal point of this paper is a DEMATEL approach based on fuzzy sets,with the attempt to use these fuzzy sets explicitly.Using this approach,the cause–effect diagram of gas turbine failures expressed in the literature is generated and aimed to create a perspective for operators.The results of the study show that,"connecting shaft has been broken between turbine and gear box"selected the most important cause factor and"sufficient pressure fuel does not come for fuel pump"is selected the most important effect factor,according to the experts.展开更多
Captive model tests are one of the most common methods to calculate the maneuvering hydrodynamic coefficients and characteristics of surface and underwater vehicles.Considerable attention must be paid to selecting and...Captive model tests are one of the most common methods to calculate the maneuvering hydrodynamic coefficients and characteristics of surface and underwater vehicles.Considerable attention must be paid to selecting and designing the most suitable laboratory equipment for towing tanks.A computational fluid dynamics(CFD)-based method is implemented to determine the loads acting on the towing facility of the submarine model.A reversed topology is also used to ensure the appropriateness of the load cells in the developed method.In this study,the numerical simulations were evaluated using the experimental results of the SUBOFF benchmark submarine model of the Defence Advanced Research Projects Agency.The maximum and minimum loads acting on the 2.5-meter submarine model were measured by determining the body’s lightest and heaviest maneuvering test scenarios.In addition to having sufficient endurance against high loads,the precision in measuring the light load was also investigated.The horizontal planar motion mechanism(HPMM)facilities in the National Iranian Marine Laboratory were developed by locating the load cells inside the submarine model.The results were presented as a case study.A numerical-based method was developed to obtain the appropriate load measurement facilities.Load cells of HPMM test basins can be selected by following the two-way procedure presented in this study.展开更多
This study proposes a multi-objective optimization framework for electric winches in fiber-reinforced plastic(FRP)fishing vessels to address critical limitations of conventional designs,including excessive weight,mate...This study proposes a multi-objective optimization framework for electric winches in fiber-reinforced plastic(FRP)fishing vessels to address critical limitations of conventional designs,including excessive weight,material inefficiency,and performance redundancy.By integrating surrogate modeling techniques with a multi-objective genetic algorithm(MOGA),we have developed a systematic approach that encompasses parametric modeling,finite element analysis under extreme operational conditions,and multi-fidelity performance evaluation.Through a 10-t electric winch case study,the methodology’s effectiveness is demonstrated via parametric characterization of structural integrity,stiffness behavior,and mass distribution.The comparative analysis identified optimal surrogate models for predicting key performance metrics,which enabled the construction of a robust multi-objective optimization model.The MOGA-derived Pareto solutions produced a design configuration achieving 7.86%mass reduction,2.01%safety factor improvement,and 23.97%deformation mitigation.Verification analysis confirmed the optimization scheme’s reliability in balancing conflicting design requirements.This research establishes a generalized framework for marine deck machinery modernization,particularly addressing the structural compatibility challenges in FRP vessel retrofitting.The proposed methodology demonstrates significant potential for facilitating sustainable upgrades of fishing vessel equipment through systematic performance optimization.展开更多
Higher education is at the top of the educational hierarchy.With the booming development of the economy and society in China,its scale is also expanding greatly.Professional course teaching is a key component of highe...Higher education is at the top of the educational hierarchy.With the booming development of the economy and society in China,its scale is also expanding greatly.Professional course teaching is a key component of higher education,and it plays a vital role in cultivating professionalism and even the overall level of students.According to several problems existing in the current teaching practice of professional courses at our universities,in order to improve the teaching quality to meet the requirements in the emerging engineering era,related strategies and approaches for teaching reform are proposed as follows.Firstly,we advance the traditional classroom teaching into the modern one with equal double-subjects of teachers and students to cultivate the active and comprehensive learning ability of students.Secondly,the scientific research practice-oriented teaching method is introduced,and it contributes to connecting theory with engineering practice for students.Thirdly,the diversified course assessment system is explored,and a closed-loop quality control strategy is discussed on the basis of a questionnaire survey and face-to-face interview.By questionnaires and final assessments,it is clear that teaching qualities of related professional courses are satisfactory in recent years,and the methods and strategies can be widely applied to the teaching practice of other courses.展开更多
Corrosion of reinforcement induced by chloride invasion is extensively considered as the dominating deterioration mechanism of reinforced concrete(RC)structures,leading to serious safety hazards and tremendous economi...Corrosion of reinforcement induced by chloride invasion is extensively considered as the dominating deterioration mechanism of reinforced concrete(RC)structures,leading to serious safety hazards and tremendous economic losses.However,it still lacks well dispersive and cost-efficient nanomaterials to improve the anti-chloride-corrosion ability of RC structures.Herein,specific carbon dots(CDs)with high dispersity and low cost are deliberately designed,successfully prepared by hydrothermal processing,and then firstly applied to immensely enhance chloride binding performance of cement,thereby contributing to suppressing the corrosion of reinforcement.Specifically,the tailored CDs are composed of the carbon core with highly crystalline sp^(2)C structures and oxygen-containing groups connecting on the carbon core;The typical equilibrium test confirms that with respect to that of the blank cement paste,the chloride binding capacity of cement paste involving 0.2 wt%(by weight of cement)CDs is increased by 109% after 14-day exposure to 3 mol/L Na Cl solution;according to comprehensive analyses of phase compositions,the chloride binding mechanism of CDs-modified cement is rationally attributed to the fact that the incorporation of CDs advances the formation of calcium silicate hydrate(C-S-H)gels and Friedel's salt(Fs),thus enormously enhancing the physically adsorbed and chemically bound chloride ions of cement pastes.This work not only firstly provides a novel high-dispersity and low-cost nanomaterial toward the durability enhancement of RC structures,but also broadens the application of CDs in the field of engineering,conducing to stimulating their industrialization development.展开更多
To prolong the service lifetime of hot-section components used in marine environment at elevated tem-peratures,it is crucial to explore and develop high-temperature corrosion-resistant coatings.High-velocity oxygen fu...To prolong the service lifetime of hot-section components used in marine environment at elevated tem-peratures,it is crucial to explore and develop high-temperature corrosion-resistant coatings.High-velocity oxygen fuel(HVOF)sprayed NiCoCrAlY,Pt-modified NiCoCrAlY and pre-oxidized Pt-modified NiCoCrAlY coatings were prepared and investigated.This study is concerned with the performance of three coat-ings in a simulated marine environment based on the phase composition of corrosion products and mi-crostructure evolution of coating samples combined with first-principles density functional theory.The results show that the NiCoCrAlY coating was subject to accelerated corrosion and extensive aluminum depletion,leading to premature coating failure.The high-temperature corrosion resistance of Pt-modified NiCoCrAlY coating was found to be better than that of NiCoCrAlY coating.In contrast,the pre-oxidized Pt-modified NiCoCrAlY coating offered long-lasting protection and exhibited the best corrosion resistance,which is attributed to the positive synergistic effect between Pt modification and pre-oxidation.展开更多
To reduce the greenhouse gases as per the forthcoming IMO rules, ammonia seems to be a suitable fuel for marine industry since it’s a hydrogen carrier and a carbon, Sulphur, and particulate matter free fuel. It has h...To reduce the greenhouse gases as per the forthcoming IMO rules, ammonia seems to be a suitable fuel for marine industry since it’s a hydrogen carrier and a carbon, Sulphur, and particulate matter free fuel. It has high volumetric hydrogen density, low storage pressure, and high auto ignition temperature. Ammonia can be used directly in internal combustion engines, and gas turbines. Cracked hydrogen can be used for fuel cells. The 4th IMO Greenhouse Gas Study 2020, estimates that if no further action is taken, international shipping emissions are expected to represent 90% to 130% of 2008 emission levels by 2050. There will also be a rise in atmospheric CO_(2) and there is already a rise in average global sea levels from 21.9 to 23.7 between 1880 and 2010. This will affect large coastal areas of the world and island nations. The challenges for ammonia are its foul odor, corrosive nature, and being highly toxic to humans and the environment. There is also an explosion risk. Other issues are bunkering and storage on board, corrosive effect on metals, shore infrastructure, commercial and technical viability. Therefore, this study gives an overview of challenges that will be faced on board ships to use ammonia as fuel.展开更多
Nowadays,new energy technologies are developing rapidly,energy storage systems are widely used,and lithium-ion batteries occupy a dominant position among them.Therefore,it is also very important to ensure their perfor...Nowadays,new energy technologies are developing rapidly,energy storage systems are widely used,and lithium-ion batteries occupy a dominant position among them.Therefore,it is also very important to ensure their performance,safety and service life through thermal management technology.In this paper,the causes of thermal runaway of lithium batteries are reviewed firstly,and three commonly used thermal management technologies,namely,air cooling,liquid cooling and phase change material cooling,are compared according to relevant literature in recent years.Air cooling technology has been widely studied because of its simple structure and low cost,but its temperature control effect is poor.Liquid cooling technology takes away heat through the circulation of liquid medium,which has a good cooling effect,but the system is relatively complex.Phase change material(PCM)cooling technology uses the high latent heat of PCM to absorb and re-lease heat,which can effectively reduce the peak temperature of a battery and improve the temperature uniformity,but the low thermal conductivity and liquid leakage are its main problems.To sum up,lithium-ion battery thermal management technology is moving towards a more efficient,safer and cost-effective direction.Coupled cooling systems,such as those combining liquid cooling and phase change material cooling,show great potential.Future research will continue to explore new materials and technologies to meet the growing demands of society and the market for lithium-ion battery perfor-mance and safety.展开更多
The aim of this study is to address the issues associated with traditional magnetorheological fluid(MRF)dampers,such as insufficient damping force after power failure and susceptibility to settlement.In order to achie...The aim of this study is to address the issues associated with traditional magnetorheological fluid(MRF)dampers,such as insufficient damping force after power failure and susceptibility to settlement.In order to achieve this,a bidirectional adjustable MRF damper was designed and developed.Magnetic field simulation analysis was conducted on the damper,along with simulation analysis on its dynamic characteristics.The dynamic characteristics were ultimately validated through experimental testing on the material testing machine,thereby corroborating the theoretical simulation results.Concurrently,this process generated valuable test data for subsequent implementation of the semi-active vibration control system.The simulation and test results demonstrate that the integrated permanent magnet effectively accomplishes bidirectional regulation.The magnetic induction intensity of the damping channel is 0.2 T in the absence of current,increases to 0.5 T when a maximum forward current of 4 A is applied,and becomes 0 T when a maximum reverse current of 3.8 A is applied.When the excitation amplitude is 8 mm and the frequency is 2 Hz,with the applied currents varying,the maximum damping force reaches 8 kN,while the minimum damping force measures at 511 N.Additionally,at zero current,the damping force stands at 2 kN,which aligns closely with simulation results.The present paper can serve as a valuable reference for the design and research of semi-active MRF dampers.展开更多
The operating environment of the diesel engine air path system is complex and may be affected by external random disturbances.Potentially leading to faults.This paper addresses the fault-tolerant control problem of th...The operating environment of the diesel engine air path system is complex and may be affected by external random disturbances.Potentially leading to faults.This paper addresses the fault-tolerant control problem of the diesel engine air path system,assuming that the system may simultaneously be affected by actuator faults and external random disturbances,a disturbance observer-based sliding mode controller is designed.Through the linear matrix inequality technique for solving observer and controller gains,optimal gain matrices can be obtained,eliminating the manual adjustment process of controller parameters and reducing the chattering phenomenon of the sliding mode surface.Finally,the effectiveness of the proposed method is verified through simulation analysis.展开更多
Human error,an important factor,may lead to serious results in various operational fields.The human factor plays a critical role in the risks and hazards of the maritime industry.A ship can achieve safe navigation whe...Human error,an important factor,may lead to serious results in various operational fields.The human factor plays a critical role in the risks and hazards of the maritime industry.A ship can achieve safe navigation when all operations in the engine room are conducted vigilantly.This paper presents a systematic evaluation of 20 failures in auxiliary systems of marine diesel engines that may be caused by human error.The Cognitive Reliability Error Analysis Method(CREAM)is used to determine the potentiality of human errors in the failures implied thanks to the answers of experts.Using this method,the probabilities of human error on failures were evaluated and the critical ones were emphasized.The measures to be taken for these results will make significant contributions not only to the seafarers but also to the ship owners.展开更多
Semisubmersible naval ships are versatile military crafts that combine the advantageous features of high-speed planing crafts and submarines.At-surface,these ships are designed to provide sufficient speed and maneuver...Semisubmersible naval ships are versatile military crafts that combine the advantageous features of high-speed planing crafts and submarines.At-surface,these ships are designed to provide sufficient speed and maneuverability.Additionally,they can perform shallow dives,offering low visual and acoustic detectability.Therefore,the hydrodynamic design of a semisubmersible naval ship should address at-surface and submerged conditions.In this study,Numerical analyses were performed using a semisubmersible hull form to analyze its hydrodynamic features,including resistance,powering,and maneuvering.The simulations were conducted with Star CCM+version 2302,a commercial package program that solves URANS equations using the SST k-ωturbulence model.The flow analysis was divided into two parts:at-surface simulations and shallowly submerged simulations.At-surface simulations cover the resistance,powering,trim,and sinkage at transition and planing regimes,with corresponding Froude numbers ranging from 0.42 to 1.69.Shallowly submerged simulations were performed at seven different submergence depths,ranging from D/LOA=0.0635 to D/LOA=0.635,and at two different speeds with Froude numbers of 0.21 and 0.33.The behaviors of the hydrodynamic forces and pitching moment for different operation depths were comprehensively analyzed.The results of the numerical analyses provide valuable insights into the hydrodynamic performance of semisubmersible naval ships,highlighting the critical factors influencing their resistance,powering,and maneuvering capabilities in both at-surface and submerged conditions.展开更多
To enable optimal navigation for unmanned surface vehicle(USV),we proposed an adaptive hybrid strategy-based sparrow search algorithm(SSA)for efficient and reliable path planning.The proposed method began by enhancing...To enable optimal navigation for unmanned surface vehicle(USV),we proposed an adaptive hybrid strategy-based sparrow search algorithm(SSA)for efficient and reliable path planning.The proposed method began by enhancing the fitness function to comprehensively account for critical path planning metrics,including path length,turning angle,and navigation safety.To improve search diversity and effectively avoid premature convergence to local optima,chaotic mapping was employed during the population initialization stage,allowing the algorithm to explore a wider solution space from the outset.A reverse inertia weight mechanism was introduced to dynamically balance exploration and exploitation across different iterations.The adaptive adjustment of the inertia weight further improved convergence efficiency and enhanced global optimization performance.In addition,a Cauchy-Gaussian hybrid update strategy was incorporated to inject randomness and variation into the search process,which helped the algorithm escape local minima and maintain a high level of solution diversity.This approach significantly enhanced the robustness and adaptability of the optimization process.Simulation experiments confirmed that the improved SSA consistently outperformed benchmark algorithms such as the original SSA,PSO,and WMR-SSA.Compared with the three algorithms,in the simulated sea area,the path lengths of the proposed algorithm are reduced by 21%,21%,and 16%,respectively,and under the actual sea simulation conditions,the path lengths are reduced by 13%,15%,and 11%,respectively.The results highlighted the effectiveness and practicality of the proposed method,providing an effective solution for intelligent and autonomous USV navigation in complex ocean environments.展开更多
Geological sequestration of carbon dioxide(CO_(2))entails the long-term storage of captured emissions from CCUS(Carbon Capture,Utilization,and Storage)facilities in deep saline aquifers to mitigate greenhouse gas accu...Geological sequestration of carbon dioxide(CO_(2))entails the long-term storage of captured emissions from CCUS(Carbon Capture,Utilization,and Storage)facilities in deep saline aquifers to mitigate greenhouse gas accumulation.Among various trapping mechanisms,dissolution trapping is particularly effective in enhancing storage security.However,the stratified structure of saline aquifers plays a crucial role in controlling the efficiency of CO_(2) dissolution into the resident brine.In this study,a two-dimensional numerical model of a stratified saline aquifer is developed,integrating both two-phase flow and mass transfer dynamics.The model captures the temporal evolution of gas saturation,reservoir pressure,and CO_(2) dissolution behavior under varying geological and operational conditions.Specifically,the effects of porosity heterogeneity,permeability distribution,and injection rate on the dissolution process are examined,and sequestration efficiencies across distinct stratigraphic layers are compared.Simulation results reveal that in the early phase of CO_(2) injection,the plume spreads radially along the lower portion of the aquifer.With continued injection,high-saturation regions expand upward and eventually accumulate beneath the shale and caprock layers.Pressure within the reservoir rises in response to CO_(2) injection,propagating both vertically and laterally.CO_(2) migration and dissolution are strongly influenced by reservoir properties,with progressive dissolution occurring in the pore spaces of individual layers.High-porosity zones favor CO_(2) accumulation and enhance local dissolution,whereas low-porosity regions facilitate vertical diffusion.An increase in porosity from 0.25 to 0.30 reduces the radial extent of dissolution in the high-permeability layer by 16.5%.Likewise,increasing permeability promotes radial dispersion;each 10 mD increment extends the CO_(2) dissolution front by approximately 18 m.Elevated injection rates intensify both vertical and lateral plume migration:every 0.25×10^(−6) m/s increase in rate yields an average 100–120 m increase in radial dissolution distance within high-permeability zones.展开更多
High-entropy(HE)design provides ample opportunities for accessing catalysts with unique physiochemical properties for advanced energy and environmental applications.Although a variety of multi-cationic high-entropy ma...High-entropy(HE)design provides ample opportunities for accessing catalysts with unique physiochemical properties for advanced energy and environmental applications.Although a variety of multi-cationic high-entropy materials(HEMs)have been identified,HEMs consisted of multiple cationic and anionic elements are still limited.Herein,we present the design and synthesis of a series of rutile-structured high-entropy oxy fluorides(HEOFs),including[RuO_(2)]_(x)[MgMnZnCoF_(2)]_(y),[MnO_(2)]_(x)[MgMnZnCoF_(2)]_(y),[MoO_(2)]_(x)[MgMnZnCoF_(2)]_(y),[SnO_(2)]_(x)[MgMnZnCoF_(2)]_(y)and[TiO_(2)]_(x)[MgMnZnCoF_(2)]_(y)(x:y=3:1,2:1,1:1).All the HEOFs are obtained through mechanochemical alloying rutile-structured oxide and fluoride precursors and the HEOFs inherit the crystal structures of the skeleton oxides.Moreover,the HEOFs exhibit enhanced electrocatalytic oxygen evolution reaction(OER)activity than the corresponding oneelement precursors.Typically,the best-performed HEOF[RuO_(2)]_(3)[MgMnZnCoF_(2)]_(1)catalyst requires an overpotential of 240 mV to achieve a current density of 10 mA cm^(-2),which is lower than RuO_(2)(291 mV),More impressively,the specific mass activity of[RuO_(2)]_(3)[MgMnZnCoF_(2)]_(1)is 537.1 A g_(Ru)^(-1)at1.55 V(vs RHE),which is ca.7.6 times that of RuO_(2)(70.5 A g_(Ru)^(-1)).The enhanced electrocata lytic OER performance obtained on[RuO_(2)]_(3)[MgMnZnCoF_(2)]_(1)is ascribed to the contribution of the different cationic and anionic elements that modulates the electronic structures of the pristine RuO_(2),which facilitates efficient OER kinetics.This work demonstrates the efficacy of high-entropy design towards approaching excellent catalysts for enhanced electrocatalysis.展开更多
HKUST-1 is being considered as a promising storage medium for adsorbed natural gas(ANG),but the practical application still calls for the improvement on the adsorption capacity for methane,hydrostability and apparent ...HKUST-1 is being considered as a promising storage medium for adsorbed natural gas(ANG),but the practical application still calls for the improvement on the adsorption capacity for methane,hydrostability and apparent thermal conductivity.Here,incorporation and carbonization were employed to ameliorate the performances of HKUST-1,and the effect of mixing graphene oxide(GO)and graphite intercalation compounds(GIC)as well as equipping honeycomb heat exchanging device(HHED)on mitigating the thermal effect was also evaluated.Researches were conducted in terms of adsorption equilibrium of methane on the samples and the dynamic characteristic of a storage vessel during a typical flow rate of charge/discharge which is in correspondence with the typical consumption rate of the fuel required by the power unit.Results show that,in comparing with those of the sample(GOH-5)prepared by incorporating with 5%(mass)GO,the sample(EH-2)incorporated with the same mass of composite formed by mixing GO and GIC in a mass ratio 2:1 had 2.0%,4.4%,1.2%and 28.4%increment in specific surface area,specific microporous volume,mean pore width and thermal conductivity.Results also reveal that,within the temperature-pressure range 273-323 K and 0.3-3.5 MPa,the mean useable capacity(UC)of methane on EH-2 and GOH-5 samples consolidated under pressure 2 MPa is nearly equal,and the average useable capacity ratio(UCR)on the storage system obtained the largest value while HHED+GOH-P(formed by GOH-5 under pressure 2 MPa)was filled into the system.It suggests that incorporating HKUST-1 with composite contained certain amount of GIC is conducive to improving the thermal conductivity,but equipping HHED within the storage system is more effective in improving the performance of the ANG system.展开更多
The penetration of ogival-nosed projectiles into ship plates represents a complex impact dynamics issue essential for analyzing structural failuremechanisms.Although stiffenedplates are vital in ship construction,fews...The penetration of ogival-nosed projectiles into ship plates represents a complex impact dynamics issue essential for analyzing structural failuremechanisms.Although stiffenedplates are vital in ship construction,fewstudies have addressed the issue of model equivalence under penetration loading.This study employs numerical simulation to validate an experiment with an ogival-nosed projectile penetrating a Q345 steel plate.Four equivalent stiffened plate methods are proposed based on the area,flexural modulus,moment of inertia,and thickness.The results indicate that thickness equivalence(DM4)is unsuitable for penetration-loaded stiffened plates,except under low-speed,nonpenetrating through impacts,and yields less accuracy than DM1/DM3.DM1,DM2,and DM3 each perform optimally with specific velocity ranges:DM1 at very low(critical)and high velocities,DM3 at low velocities,and DM2 at high speeds.Furthermore,in penetration scenarios,T-shaped stiffeners can be replacedwith rectangular ones,as both exhibit similar failure behaviors and deflection trends,simplifying the design while preserving key structural characteristics.These findings provide valuable insights into the design of protective ship structures.展开更多
As intelligent sensors for marine applications rapidly advance,there is a growing emphasis on developing efficient,low-cost,and sustainable power sources to enhance their performance.With the continuous development of...As intelligent sensors for marine applications rapidly advance,there is a growing emphasis on developing efficient,low-cost,and sustainable power sources to enhance their performance.With the continuous development of triboelectric nanogenerators(TENGs),known for their simple structure and versatile operational modes,these devices exhibit promising technological potential and have garnered extensive attention from a broad spectrum of researchers.The single-electrode mode of TENGs presents an effective means to harness eco-friendly energy sourced from flowing water.In this study,the factors affecting the output performance were investigated using different structures of single-electrode solid-liquid TENGs placed in a circulating water tank.In addition,the solid‒liquid contact process was numerically simulated using the COMSOL Multiphysics software,and significant potential energy changes were obtained for the solid‒liquid contact and liquid flow processes.Finally,the energy generated is collected and converted to power several light-emitting diodes,demonstrating that solid‒liquid TENGs can generate effective electrical power in a flowing water environment.Through several experimental investigations,we finally determined that the flow rate of the liquid,the thickness of the friction electrode material,and the contact area have the most significant effect on the output efficiency of TENGs in the form of flowing water,which provides a guide for improving their performance in the future.展开更多
In the rapidly evolving technological landscape,state-owned enterprises(SOEs)encounter significant challenges in sustaining their competitiveness through efficient R&D management.Integrated Product Development(IPD...In the rapidly evolving technological landscape,state-owned enterprises(SOEs)encounter significant challenges in sustaining their competitiveness through efficient R&D management.Integrated Product Development(IPD),with its emphasis on cross-functional teamwork,concurrent engineering,and data-driven decision-making,has been widely recognized for enhancing R&D efficiency and product quality.However,the unique characteristics of SOEs pose challenges to the effective implementation of IPD.The advancement of big data and artificial intelligence technologies offers new opportunities for optimizing IPD R&D management through data-driven decision-making models.This paper constructs and validates a data-driven decision-making model tailored to the IPD R&D management of SOEs.By integrating data mining,machine learning,and other advanced analytical techniques,the model serves as a scientific and efficient decision-making tool.It aids SOEs in optimizing R&D resource allocation,shortening product development cycles,reducing R&D costs,and improving product quality and innovation.Moreover,this study contributes to a deeper theoretical understanding of the value of data-driven decision-making in the context of IPD.展开更多
An Interval Type-2(IT-2)fuzzy controller design approach is proposed in this research to simultaneously achievemultiple control objectives inNonlinearMulti-Agent Systems(NMASs),including formation,containment,and coll...An Interval Type-2(IT-2)fuzzy controller design approach is proposed in this research to simultaneously achievemultiple control objectives inNonlinearMulti-Agent Systems(NMASs),including formation,containment,and collision avoidance.However,inherent nonlinearities and uncertainties present in practical control systems contribute to the challenge of achieving precise control performance.Based on the IT-2 Takagi-Sugeno Fuzzy Model(T-SFM),the fuzzy control approach can offer a more effective solution for NMASs facing uncertainties.Unlike existing control methods for NMASs,the Formation and Containment(F-and-C)control problem with collision avoidance capability under uncertainties based on the IT-2 T-SFM is discussed for the first time.Moreover,an IT-2 fuzzy tracking control approach is proposed to solve the formation task for leaders in NMASs without requiring communication.This control scheme makes the design process of the IT-2 fuzzy Formation Controller(FC)more straightforward and effective.According to the communication interaction protocol,the IT-2 Containment Controller(CC)design approach is proposed for followers to ensure convergence into the region defined by the leaders.Leveraging the IT-2 T-SFM representation,the analysis methods developed for linear Multi-Agent Systems(MASs)are successfully extended to perform containment analysis without requiring the additional assumptions imposed in existing research.Notably,the IT-2 fuzzy tracking controller can also be applied in collision avoidance situations to track the desired trajectories calculated by the avoidance algorithm under the Artificial Potential Field(APF).Benefiting from the combination of vortex and source APFs,the leaders can properly adjust the system dynamics to prevent potential collision risk.Integrating the fuzzy theory and APFs avoidance algorithm,an IT-2 fuzzy controller design approach is proposed to achieve the F-and-C purposewhile ensuring collision avoidance capability.Finally,amulti-ship simulation is conducted to validate the feasibility and effectiveness of the designed IT-2 fuzzy controller.展开更多
文摘In power production,gas turbines are commonly used components that generate high amount of energy depending on size and weight.They function as integral parts of helicopters,aircrafts,trains,ships,electrical generators,and tanks.Notably,many researchers are focusing on the design,operation,and maintenance of gas turbines.The focal point of this paper is a DEMATEL approach based on fuzzy sets,with the attempt to use these fuzzy sets explicitly.Using this approach,the cause–effect diagram of gas turbine failures expressed in the literature is generated and aimed to create a perspective for operators.The results of the study show that,"connecting shaft has been broken between turbine and gear box"selected the most important cause factor and"sufficient pressure fuel does not come for fuel pump"is selected the most important effect factor,according to the experts.
文摘Captive model tests are one of the most common methods to calculate the maneuvering hydrodynamic coefficients and characteristics of surface and underwater vehicles.Considerable attention must be paid to selecting and designing the most suitable laboratory equipment for towing tanks.A computational fluid dynamics(CFD)-based method is implemented to determine the loads acting on the towing facility of the submarine model.A reversed topology is also used to ensure the appropriateness of the load cells in the developed method.In this study,the numerical simulations were evaluated using the experimental results of the SUBOFF benchmark submarine model of the Defence Advanced Research Projects Agency.The maximum and minimum loads acting on the 2.5-meter submarine model were measured by determining the body’s lightest and heaviest maneuvering test scenarios.In addition to having sufficient endurance against high loads,the precision in measuring the light load was also investigated.The horizontal planar motion mechanism(HPMM)facilities in the National Iranian Marine Laboratory were developed by locating the load cells inside the submarine model.The results were presented as a case study.A numerical-based method was developed to obtain the appropriate load measurement facilities.Load cells of HPMM test basins can be selected by following the two-way procedure presented in this study.
基金supported by the Basic Public Welfare Research Program of Zhejiang Province(No.LGN22E050005).
文摘This study proposes a multi-objective optimization framework for electric winches in fiber-reinforced plastic(FRP)fishing vessels to address critical limitations of conventional designs,including excessive weight,material inefficiency,and performance redundancy.By integrating surrogate modeling techniques with a multi-objective genetic algorithm(MOGA),we have developed a systematic approach that encompasses parametric modeling,finite element analysis under extreme operational conditions,and multi-fidelity performance evaluation.Through a 10-t electric winch case study,the methodology’s effectiveness is demonstrated via parametric characterization of structural integrity,stiffness behavior,and mass distribution.The comparative analysis identified optimal surrogate models for predicting key performance metrics,which enabled the construction of a robust multi-objective optimization model.The MOGA-derived Pareto solutions produced a design configuration achieving 7.86%mass reduction,2.01%safety factor improvement,and 23.97%deformation mitigation.Verification analysis confirmed the optimization scheme’s reliability in balancing conflicting design requirements.This research establishes a generalized framework for marine deck machinery modernization,particularly addressing the structural compatibility challenges in FRP vessel retrofitting.The proposed methodology demonstrates significant potential for facilitating sustainable upgrades of fishing vessel equipment through systematic performance optimization.
基金Undergraduate Education Reform Project of Dalian Maritime University(BJG-C2024072)Postgraduate Education Reform Project of Liaoning Province([2022]249-209)+1 种基金Education Reform Project of Dalian Minzu University(YB202547,YJS2024JG55,B2109)First-Class Undergraduate Courses of Liaoning Province([2022]302-1433,[2022]302-1452)。
文摘Higher education is at the top of the educational hierarchy.With the booming development of the economy and society in China,its scale is also expanding greatly.Professional course teaching is a key component of higher education,and it plays a vital role in cultivating professionalism and even the overall level of students.According to several problems existing in the current teaching practice of professional courses at our universities,in order to improve the teaching quality to meet the requirements in the emerging engineering era,related strategies and approaches for teaching reform are proposed as follows.Firstly,we advance the traditional classroom teaching into the modern one with equal double-subjects of teachers and students to cultivate the active and comprehensive learning ability of students.Secondly,the scientific research practice-oriented teaching method is introduced,and it contributes to connecting theory with engineering practice for students.Thirdly,the diversified course assessment system is explored,and a closed-loop quality control strategy is discussed on the basis of a questionnaire survey and face-to-face interview.By questionnaires and final assessments,it is clear that teaching qualities of related professional courses are satisfactory in recent years,and the methods and strategies can be widely applied to the teaching practice of other courses.
基金financially supported by the National Natural Science Foundation of China-Youth Science Fund(No.52208273)the National Natural Science Foundations of ChinaNSFCShandong Joint Fund(No.U2006223)。
文摘Corrosion of reinforcement induced by chloride invasion is extensively considered as the dominating deterioration mechanism of reinforced concrete(RC)structures,leading to serious safety hazards and tremendous economic losses.However,it still lacks well dispersive and cost-efficient nanomaterials to improve the anti-chloride-corrosion ability of RC structures.Herein,specific carbon dots(CDs)with high dispersity and low cost are deliberately designed,successfully prepared by hydrothermal processing,and then firstly applied to immensely enhance chloride binding performance of cement,thereby contributing to suppressing the corrosion of reinforcement.Specifically,the tailored CDs are composed of the carbon core with highly crystalline sp^(2)C structures and oxygen-containing groups connecting on the carbon core;The typical equilibrium test confirms that with respect to that of the blank cement paste,the chloride binding capacity of cement paste involving 0.2 wt%(by weight of cement)CDs is increased by 109% after 14-day exposure to 3 mol/L Na Cl solution;according to comprehensive analyses of phase compositions,the chloride binding mechanism of CDs-modified cement is rationally attributed to the fact that the incorporation of CDs advances the formation of calcium silicate hydrate(C-S-H)gels and Friedel's salt(Fs),thus enormously enhancing the physically adsorbed and chemically bound chloride ions of cement pastes.This work not only firstly provides a novel high-dispersity and low-cost nanomaterial toward the durability enhancement of RC structures,but also broadens the application of CDs in the field of engineering,conducing to stimulating their industrialization development.
基金supported by the National Science and Technology Major Project(No.J2019-IV-0006-0074)the Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021-2-2)+2 种基金the National Natural Science Foundation of China(No.52301116)support by the Joint Funds of the National Natural Science Foundation of China(“Ye Qisun”Science Funds,No.U2241251)the Innovation Engineering Project(No.211-XXXX-N106-01).
文摘To prolong the service lifetime of hot-section components used in marine environment at elevated tem-peratures,it is crucial to explore and develop high-temperature corrosion-resistant coatings.High-velocity oxygen fuel(HVOF)sprayed NiCoCrAlY,Pt-modified NiCoCrAlY and pre-oxidized Pt-modified NiCoCrAlY coatings were prepared and investigated.This study is concerned with the performance of three coat-ings in a simulated marine environment based on the phase composition of corrosion products and mi-crostructure evolution of coating samples combined with first-principles density functional theory.The results show that the NiCoCrAlY coating was subject to accelerated corrosion and extensive aluminum depletion,leading to premature coating failure.The high-temperature corrosion resistance of Pt-modified NiCoCrAlY coating was found to be better than that of NiCoCrAlY coating.In contrast,the pre-oxidized Pt-modified NiCoCrAlY coating offered long-lasting protection and exhibited the best corrosion resistance,which is attributed to the positive synergistic effect between Pt modification and pre-oxidation.
文摘To reduce the greenhouse gases as per the forthcoming IMO rules, ammonia seems to be a suitable fuel for marine industry since it’s a hydrogen carrier and a carbon, Sulphur, and particulate matter free fuel. It has high volumetric hydrogen density, low storage pressure, and high auto ignition temperature. Ammonia can be used directly in internal combustion engines, and gas turbines. Cracked hydrogen can be used for fuel cells. The 4th IMO Greenhouse Gas Study 2020, estimates that if no further action is taken, international shipping emissions are expected to represent 90% to 130% of 2008 emission levels by 2050. There will also be a rise in atmospheric CO_(2) and there is already a rise in average global sea levels from 21.9 to 23.7 between 1880 and 2010. This will affect large coastal areas of the world and island nations. The challenges for ammonia are its foul odor, corrosive nature, and being highly toxic to humans and the environment. There is also an explosion risk. Other issues are bunkering and storage on board, corrosive effect on metals, shore infrastructure, commercial and technical viability. Therefore, this study gives an overview of challenges that will be faced on board ships to use ammonia as fuel.
基金supported by the National Natural Science Foundation of China(No.52001045).
文摘Nowadays,new energy technologies are developing rapidly,energy storage systems are widely used,and lithium-ion batteries occupy a dominant position among them.Therefore,it is also very important to ensure their performance,safety and service life through thermal management technology.In this paper,the causes of thermal runaway of lithium batteries are reviewed firstly,and three commonly used thermal management technologies,namely,air cooling,liquid cooling and phase change material cooling,are compared according to relevant literature in recent years.Air cooling technology has been widely studied because of its simple structure and low cost,but its temperature control effect is poor.Liquid cooling technology takes away heat through the circulation of liquid medium,which has a good cooling effect,but the system is relatively complex.Phase change material(PCM)cooling technology uses the high latent heat of PCM to absorb and re-lease heat,which can effectively reduce the peak temperature of a battery and improve the temperature uniformity,but the low thermal conductivity and liquid leakage are its main problems.To sum up,lithium-ion battery thermal management technology is moving towards a more efficient,safer and cost-effective direction.Coupled cooling systems,such as those combining liquid cooling and phase change material cooling,show great potential.Future research will continue to explore new materials and technologies to meet the growing demands of society and the market for lithium-ion battery perfor-mance and safety.
文摘The aim of this study is to address the issues associated with traditional magnetorheological fluid(MRF)dampers,such as insufficient damping force after power failure and susceptibility to settlement.In order to achieve this,a bidirectional adjustable MRF damper was designed and developed.Magnetic field simulation analysis was conducted on the damper,along with simulation analysis on its dynamic characteristics.The dynamic characteristics were ultimately validated through experimental testing on the material testing machine,thereby corroborating the theoretical simulation results.Concurrently,this process generated valuable test data for subsequent implementation of the semi-active vibration control system.The simulation and test results demonstrate that the integrated permanent magnet effectively accomplishes bidirectional regulation.The magnetic induction intensity of the damping channel is 0.2 T in the absence of current,increases to 0.5 T when a maximum forward current of 4 A is applied,and becomes 0 T when a maximum reverse current of 3.8 A is applied.When the excitation amplitude is 8 mm and the frequency is 2 Hz,with the applied currents varying,the maximum damping force reaches 8 kN,while the minimum damping force measures at 511 N.Additionally,at zero current,the damping force stands at 2 kN,which aligns closely with simulation results.The present paper can serve as a valuable reference for the design and research of semi-active MRF dampers.
基金Supported by the National Key R&D Program of China(2021YFB2011300)the National Natural Science Foundation of China(52275044,52205299)+1 种基金the Zhejiang Provincial Natural Science Foundation of China(Z23E050032)the China Postdoctoral Science Foundation(2022M710304).
文摘The operating environment of the diesel engine air path system is complex and may be affected by external random disturbances.Potentially leading to faults.This paper addresses the fault-tolerant control problem of the diesel engine air path system,assuming that the system may simultaneously be affected by actuator faults and external random disturbances,a disturbance observer-based sliding mode controller is designed.Through the linear matrix inequality technique for solving observer and controller gains,optimal gain matrices can be obtained,eliminating the manual adjustment process of controller parameters and reducing the chattering phenomenon of the sliding mode surface.Finally,the effectiveness of the proposed method is verified through simulation analysis.
文摘Human error,an important factor,may lead to serious results in various operational fields.The human factor plays a critical role in the risks and hazards of the maritime industry.A ship can achieve safe navigation when all operations in the engine room are conducted vigilantly.This paper presents a systematic evaluation of 20 failures in auxiliary systems of marine diesel engines that may be caused by human error.The Cognitive Reliability Error Analysis Method(CREAM)is used to determine the potentiality of human errors in the failures implied thanks to the answers of experts.Using this method,the probabilities of human error on failures were evaluated and the critical ones were emphasized.The measures to be taken for these results will make significant contributions not only to the seafarers but also to the ship owners.
文摘Semisubmersible naval ships are versatile military crafts that combine the advantageous features of high-speed planing crafts and submarines.At-surface,these ships are designed to provide sufficient speed and maneuverability.Additionally,they can perform shallow dives,offering low visual and acoustic detectability.Therefore,the hydrodynamic design of a semisubmersible naval ship should address at-surface and submerged conditions.In this study,Numerical analyses were performed using a semisubmersible hull form to analyze its hydrodynamic features,including resistance,powering,and maneuvering.The simulations were conducted with Star CCM+version 2302,a commercial package program that solves URANS equations using the SST k-ωturbulence model.The flow analysis was divided into two parts:at-surface simulations and shallowly submerged simulations.At-surface simulations cover the resistance,powering,trim,and sinkage at transition and planing regimes,with corresponding Froude numbers ranging from 0.42 to 1.69.Shallowly submerged simulations were performed at seven different submergence depths,ranging from D/LOA=0.0635 to D/LOA=0.635,and at two different speeds with Froude numbers of 0.21 and 0.33.The behaviors of the hydrodynamic forces and pitching moment for different operation depths were comprehensively analyzed.The results of the numerical analyses provide valuable insights into the hydrodynamic performance of semisubmersible naval ships,highlighting the critical factors influencing their resistance,powering,and maneuvering capabilities in both at-surface and submerged conditions.
基金supported by Shandong Provincial Department of Science and Technology Project(No.2022C01246)National Undergraduate Innovation Training Project(Nos.202410390028,202310390026)+1 种基金Fujian Provincial Undergraduate Innovation Training Project(No.202410390093)Jimei University Innovation Training Project(Nos.2024xj224,2023xj179).
文摘To enable optimal navigation for unmanned surface vehicle(USV),we proposed an adaptive hybrid strategy-based sparrow search algorithm(SSA)for efficient and reliable path planning.The proposed method began by enhancing the fitness function to comprehensively account for critical path planning metrics,including path length,turning angle,and navigation safety.To improve search diversity and effectively avoid premature convergence to local optima,chaotic mapping was employed during the population initialization stage,allowing the algorithm to explore a wider solution space from the outset.A reverse inertia weight mechanism was introduced to dynamically balance exploration and exploitation across different iterations.The adaptive adjustment of the inertia weight further improved convergence efficiency and enhanced global optimization performance.In addition,a Cauchy-Gaussian hybrid update strategy was incorporated to inject randomness and variation into the search process,which helped the algorithm escape local minima and maintain a high level of solution diversity.This approach significantly enhanced the robustness and adaptability of the optimization process.Simulation experiments confirmed that the improved SSA consistently outperformed benchmark algorithms such as the original SSA,PSO,and WMR-SSA.Compared with the three algorithms,in the simulated sea area,the path lengths of the proposed algorithm are reduced by 21%,21%,and 16%,respectively,and under the actual sea simulation conditions,the path lengths are reduced by 13%,15%,and 11%,respectively.The results highlighted the effectiveness and practicality of the proposed method,providing an effective solution for intelligent and autonomous USV navigation in complex ocean environments.
基金supported by the National Natural Science Foundation of China(No.52306187)the Fundamental Research Funds for the Central Universities of China(Grant No.3132024205)the Open Fund of Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education(Grant No.LOEC-202004).
文摘Geological sequestration of carbon dioxide(CO_(2))entails the long-term storage of captured emissions from CCUS(Carbon Capture,Utilization,and Storage)facilities in deep saline aquifers to mitigate greenhouse gas accumulation.Among various trapping mechanisms,dissolution trapping is particularly effective in enhancing storage security.However,the stratified structure of saline aquifers plays a crucial role in controlling the efficiency of CO_(2) dissolution into the resident brine.In this study,a two-dimensional numerical model of a stratified saline aquifer is developed,integrating both two-phase flow and mass transfer dynamics.The model captures the temporal evolution of gas saturation,reservoir pressure,and CO_(2) dissolution behavior under varying geological and operational conditions.Specifically,the effects of porosity heterogeneity,permeability distribution,and injection rate on the dissolution process are examined,and sequestration efficiencies across distinct stratigraphic layers are compared.Simulation results reveal that in the early phase of CO_(2) injection,the plume spreads radially along the lower portion of the aquifer.With continued injection,high-saturation regions expand upward and eventually accumulate beneath the shale and caprock layers.Pressure within the reservoir rises in response to CO_(2) injection,propagating both vertically and laterally.CO_(2) migration and dissolution are strongly influenced by reservoir properties,with progressive dissolution occurring in the pore spaces of individual layers.High-porosity zones favor CO_(2) accumulation and enhance local dissolution,whereas low-porosity regions facilitate vertical diffusion.An increase in porosity from 0.25 to 0.30 reduces the radial extent of dissolution in the high-permeability layer by 16.5%.Likewise,increasing permeability promotes radial dispersion;each 10 mD increment extends the CO_(2) dissolution front by approximately 18 m.Elevated injection rates intensify both vertical and lateral plume migration:every 0.25×10^(−6) m/s increase in rate yields an average 100–120 m increase in radial dissolution distance within high-permeability zones.
基金financially supported by the National Natural Science Foundation of China(Grant No.22179015,21872142,22302026)the Liao Ning Revitalization Talents Program(XLYC1807196)+1 种基金the fund of the State Key Laboratory of Catalysis in DICP(N-22-06)the open fund of the State Key Laboratory of Molecular Reaction Dynamics in DICP,CAS(SKLMRD-K202414)。
文摘High-entropy(HE)design provides ample opportunities for accessing catalysts with unique physiochemical properties for advanced energy and environmental applications.Although a variety of multi-cationic high-entropy materials(HEMs)have been identified,HEMs consisted of multiple cationic and anionic elements are still limited.Herein,we present the design and synthesis of a series of rutile-structured high-entropy oxy fluorides(HEOFs),including[RuO_(2)]_(x)[MgMnZnCoF_(2)]_(y),[MnO_(2)]_(x)[MgMnZnCoF_(2)]_(y),[MoO_(2)]_(x)[MgMnZnCoF_(2)]_(y),[SnO_(2)]_(x)[MgMnZnCoF_(2)]_(y)and[TiO_(2)]_(x)[MgMnZnCoF_(2)]_(y)(x:y=3:1,2:1,1:1).All the HEOFs are obtained through mechanochemical alloying rutile-structured oxide and fluoride precursors and the HEOFs inherit the crystal structures of the skeleton oxides.Moreover,the HEOFs exhibit enhanced electrocatalytic oxygen evolution reaction(OER)activity than the corresponding oneelement precursors.Typically,the best-performed HEOF[RuO_(2)]_(3)[MgMnZnCoF_(2)]_(1)catalyst requires an overpotential of 240 mV to achieve a current density of 10 mA cm^(-2),which is lower than RuO_(2)(291 mV),More impressively,the specific mass activity of[RuO_(2)]_(3)[MgMnZnCoF_(2)]_(1)is 537.1 A g_(Ru)^(-1)at1.55 V(vs RHE),which is ca.7.6 times that of RuO_(2)(70.5 A g_(Ru)^(-1)).The enhanced electrocata lytic OER performance obtained on[RuO_(2)]_(3)[MgMnZnCoF_(2)]_(1)is ascribed to the contribution of the different cationic and anionic elements that modulates the electronic structures of the pristine RuO_(2),which facilitates efficient OER kinetics.This work demonstrates the efficacy of high-entropy design towards approaching excellent catalysts for enhanced electrocatalysis.
基金supported by National Natural Science Foundation of China(51979121)Natural Science Foundation of Fujian Province(2024J01713)Xiamen Municipal Bureau of Sciences&Technology(3502Z20226011).
文摘HKUST-1 is being considered as a promising storage medium for adsorbed natural gas(ANG),but the practical application still calls for the improvement on the adsorption capacity for methane,hydrostability and apparent thermal conductivity.Here,incorporation and carbonization were employed to ameliorate the performances of HKUST-1,and the effect of mixing graphene oxide(GO)and graphite intercalation compounds(GIC)as well as equipping honeycomb heat exchanging device(HHED)on mitigating the thermal effect was also evaluated.Researches were conducted in terms of adsorption equilibrium of methane on the samples and the dynamic characteristic of a storage vessel during a typical flow rate of charge/discharge which is in correspondence with the typical consumption rate of the fuel required by the power unit.Results show that,in comparing with those of the sample(GOH-5)prepared by incorporating with 5%(mass)GO,the sample(EH-2)incorporated with the same mass of composite formed by mixing GO and GIC in a mass ratio 2:1 had 2.0%,4.4%,1.2%and 28.4%increment in specific surface area,specific microporous volume,mean pore width and thermal conductivity.Results also reveal that,within the temperature-pressure range 273-323 K and 0.3-3.5 MPa,the mean useable capacity(UC)of methane on EH-2 and GOH-5 samples consolidated under pressure 2 MPa is nearly equal,and the average useable capacity ratio(UCR)on the storage system obtained the largest value while HHED+GOH-P(formed by GOH-5 under pressure 2 MPa)was filled into the system.It suggests that incorporating HKUST-1 with composite contained certain amount of GIC is conducive to improving the thermal conductivity,but equipping HHED within the storage system is more effective in improving the performance of the ANG system.
基金supported by Natural Science Foundation of Fujian Province(2022I0019)Scientific Research Foundation for Jimei University(ZQ2024041,ZQ2024042).
文摘The penetration of ogival-nosed projectiles into ship plates represents a complex impact dynamics issue essential for analyzing structural failuremechanisms.Although stiffenedplates are vital in ship construction,fewstudies have addressed the issue of model equivalence under penetration loading.This study employs numerical simulation to validate an experiment with an ogival-nosed projectile penetrating a Q345 steel plate.Four equivalent stiffened plate methods are proposed based on the area,flexural modulus,moment of inertia,and thickness.The results indicate that thickness equivalence(DM4)is unsuitable for penetration-loaded stiffened plates,except under low-speed,nonpenetrating through impacts,and yields less accuracy than DM1/DM3.DM1,DM2,and DM3 each perform optimally with specific velocity ranges:DM1 at very low(critical)and high velocities,DM3 at low velocities,and DM2 at high speeds.Furthermore,in penetration scenarios,T-shaped stiffeners can be replacedwith rectangular ones,as both exhibit similar failure behaviors and deflection trends,simplifying the design while preserving key structural characteristics.These findings provide valuable insights into the design of protective ship structures.
基金the support from Natural Science Foundation of Heilongjiang Province(No.YQ2022A004)National Natural Science Foundation of China(No.12372268,No.12332014).
文摘As intelligent sensors for marine applications rapidly advance,there is a growing emphasis on developing efficient,low-cost,and sustainable power sources to enhance their performance.With the continuous development of triboelectric nanogenerators(TENGs),known for their simple structure and versatile operational modes,these devices exhibit promising technological potential and have garnered extensive attention from a broad spectrum of researchers.The single-electrode mode of TENGs presents an effective means to harness eco-friendly energy sourced from flowing water.In this study,the factors affecting the output performance were investigated using different structures of single-electrode solid-liquid TENGs placed in a circulating water tank.In addition,the solid‒liquid contact process was numerically simulated using the COMSOL Multiphysics software,and significant potential energy changes were obtained for the solid‒liquid contact and liquid flow processes.Finally,the energy generated is collected and converted to power several light-emitting diodes,demonstrating that solid‒liquid TENGs can generate effective electrical power in a flowing water environment.Through several experimental investigations,we finally determined that the flow rate of the liquid,the thickness of the friction electrode material,and the contact area have the most significant effect on the output efficiency of TENGs in the form of flowing water,which provides a guide for improving their performance in the future.
文摘In the rapidly evolving technological landscape,state-owned enterprises(SOEs)encounter significant challenges in sustaining their competitiveness through efficient R&D management.Integrated Product Development(IPD),with its emphasis on cross-functional teamwork,concurrent engineering,and data-driven decision-making,has been widely recognized for enhancing R&D efficiency and product quality.However,the unique characteristics of SOEs pose challenges to the effective implementation of IPD.The advancement of big data and artificial intelligence technologies offers new opportunities for optimizing IPD R&D management through data-driven decision-making models.This paper constructs and validates a data-driven decision-making model tailored to the IPD R&D management of SOEs.By integrating data mining,machine learning,and other advanced analytical techniques,the model serves as a scientific and efficient decision-making tool.It aids SOEs in optimizing R&D resource allocation,shortening product development cycles,reducing R&D costs,and improving product quality and innovation.Moreover,this study contributes to a deeper theoretical understanding of the value of data-driven decision-making in the context of IPD.
基金founded by the National Science and Technology Council of the Republic of China under contract NSTC113-2221-E-019-032.
文摘An Interval Type-2(IT-2)fuzzy controller design approach is proposed in this research to simultaneously achievemultiple control objectives inNonlinearMulti-Agent Systems(NMASs),including formation,containment,and collision avoidance.However,inherent nonlinearities and uncertainties present in practical control systems contribute to the challenge of achieving precise control performance.Based on the IT-2 Takagi-Sugeno Fuzzy Model(T-SFM),the fuzzy control approach can offer a more effective solution for NMASs facing uncertainties.Unlike existing control methods for NMASs,the Formation and Containment(F-and-C)control problem with collision avoidance capability under uncertainties based on the IT-2 T-SFM is discussed for the first time.Moreover,an IT-2 fuzzy tracking control approach is proposed to solve the formation task for leaders in NMASs without requiring communication.This control scheme makes the design process of the IT-2 fuzzy Formation Controller(FC)more straightforward and effective.According to the communication interaction protocol,the IT-2 Containment Controller(CC)design approach is proposed for followers to ensure convergence into the region defined by the leaders.Leveraging the IT-2 T-SFM representation,the analysis methods developed for linear Multi-Agent Systems(MASs)are successfully extended to perform containment analysis without requiring the additional assumptions imposed in existing research.Notably,the IT-2 fuzzy tracking controller can also be applied in collision avoidance situations to track the desired trajectories calculated by the avoidance algorithm under the Artificial Potential Field(APF).Benefiting from the combination of vortex and source APFs,the leaders can properly adjust the system dynamics to prevent potential collision risk.Integrating the fuzzy theory and APFs avoidance algorithm,an IT-2 fuzzy controller design approach is proposed to achieve the F-and-C purposewhile ensuring collision avoidance capability.Finally,amulti-ship simulation is conducted to validate the feasibility and effectiveness of the designed IT-2 fuzzy controller.
