The ocean is one of the essential fields of national defense in the future,and more and more attention is paid to the lightweight research of Marine equipment and materials.This study it is to develop a Machine learni...The ocean is one of the essential fields of national defense in the future,and more and more attention is paid to the lightweight research of Marine equipment and materials.This study it is to develop a Machine learning(ML)-based prediction method to study the evolution of the mechanical properties of Al-Li alloys in the marine environment.We obtained the mechanical properties of Al-Li alloy samples under uniaxial tensile deformation at different exposure times through Marine exposure experiments.We obtained the strain evolution by digital image correlation(DIC).The strain field images are voxelized using 2D-Convolutional Neural Networks(CNN)autoencoders as input data for Long Short-Term Memory(LSTM)neural networks.Then,the output data of LSTM neural networks combined with corrosion features were input into the Back Propagation(BP)neural network to predict the mechanical properties of Al-Li alloys.The main conclusions are as follows:1.The variation law of mechanical properties of2297-T8 in the Marine atmosphere is revealed.With the increase in outdoor exposure test time,the tensile elastic model of 2297-T8 changes slowly,within 10%,and the tensile yield stress changes significantly,with a maximum attenuation of 23.6%.2.The prediction model can predict the strain evolution and mechanical response simultaneously with an error of less than 5%.3.This study shows that a CNN/LSTM system based on machine learning can be built to capture the corrosion characteristics of Marine exposure experiments.The results show that the relationship between corrosion characteristics and mechanical response can be predicted without considering the microstructure evolution of metal materials.展开更多
Urea,paracetamol and glutamine(based on the expired drugs)were selected as vapor-phase corrosion inhibitors(VCIs)to study their corrosion protection effect on red copper in simulated marine atmospheric environment by ...Urea,paracetamol and glutamine(based on the expired drugs)were selected as vapor-phase corrosion inhibitors(VCIs)to study their corrosion protection effect on red copper in simulated marine atmospheric environment by using weight loss,electrochemical measurement techniques(specially designed electrochemical testing device for simulating marine atmospheric environments)and surface morphology characterization analysis(SEM/EDS,XRD,RAMAN,XPS).Weight loss results show that the three corrosion inhibitors have good corrosion inhibition effect on red copper,and the corrosion inhibition efficiency in the order of glutamine(83.62%)>urea(68.46%)>paracetamol(61.47%).Surface morphology characterization analysis provides evidence of adsorption of corrosion inhibitors molecules on the red copper surface,thus forming a protective film that blocked the red copper surface from the aggressive chloride ion attack.展开更多
Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,t...Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.展开更多
The study systematically investigated the impact of zinc sacrificial anode(Zn-SA)cathode protection on the corrosion of X80 steel caused by Desulfovibrio desulfuricans(D.desulfuricans)in a marine tidal environment.Uti...The study systematically investigated the impact of zinc sacrificial anode(Zn-SA)cathode protection on the corrosion of X80 steel caused by Desulfovibrio desulfuricans(D.desulfuricans)in a marine tidal environment.Utilizing weight-loss analysis,electrochemical measurements,Raman spectroscopy,and 3D morphology microscopy,the research unveiled significant findings.Unprotected steel suffered pronounced localized corrosion in the presence of D.desulfuricans in the marine tidal environment.However,the implementation of Zn-SA cathode protection notably reduced the activity of both planktonic and sessile D.desulfuricans cells.Over time,the accumulation of calcareous deposits within the corrosion products increased,as evidenced by a rise in the resistance of the corrosion produt film(Rf).Remarkably,Zn-SA cathode protection demonstrated substantial inhibition of the steel’s corrosion rate,albeit exhibiting reduced efficiency as the vertical height of the steel within the tidal environment increased.展开更多
Sloshing experiment is crucial to determine the reaction performance of regeneration columns on an offshore floating platform.A novel type of column motion simulating device and a Marine Predator Algorithm-based Slidi...Sloshing experiment is crucial to determine the reaction performance of regeneration columns on an offshore floating platform.A novel type of column motion simulating device and a Marine Predator Algorithm-based Sliding Mode Controller(MPA-SMC)are proposed for such sloshing experiments.The simulator consists of a Stewart platform and a steel framework.The Stewart platform is located at the column's center of gravity(CoG)and supported by the steel framework.The platform's hydraulic servo system is controlled by a sliding mode controller with parameters optimized by MPA to improve robustness and precision.A numerical sloshing experiment is conducted using the proposed device and controller.The results show that the novel motion simulator has lower torque during the column sloshes,and the proposed controller performs better than a well-tuned PID controller in terms of target tracking precision and anti-interference capability.展开更多
Tibet plateau is a vast hydrocarbon\|bearing region which is the biggest in area, the lowest in exploration and the poorest in knowing, especially, knowing a little for Mesozoic marine petroleum geology problem (parti...Tibet plateau is a vast hydrocarbon\|bearing region which is the biggest in area, the lowest in exploration and the poorest in knowing, especially, knowing a little for Mesozoic marine petroleum geology problem (particularly for Mesozoic marine source rock) in Chinese land. The research of oil and gas generation for Mesozoic marine source rock have been accomplished on basis of a large number of data for source rock samples appeared on the weather (29 items, about 4000 samples, 23976 sample times and 200000 data) in Tibet Plateau. Full text is composed of following four parts:1\ Regional geology\;Summarized regional geology briefly, emphasized on regional structures, sedimentary facies and stratum characteristics related closely with source rock.展开更多
Using the PimpleDyMFoam solver in open-source computing software OpenFOAM,based on the SST k-ωturbulence model and PIMPLE algorithm,a numerical simulation method of vertical-axis marine current turbines(VMCTs)is prop...Using the PimpleDyMFoam solver in open-source computing software OpenFOAM,based on the SST k-ωturbulence model and PIMPLE algorithm,a numerical simulation method of vertical-axis marine current turbines(VMCTs)is proposed,and the calculated results are compared with the experimental results.The results show that the numerical simulation method is feasible.Compared with other commercial softwares,this method has the advantages of higher solution efficiency and greater flexibility.According to the needs of users,the solver can be built on the basis of original code,and the corresponding discrete method can be optimized.This method can achieve optimization algorithms,save time and cost,etc.Secondly,the effects of different parameters(mesh density,time step,the selection of sidewall boundary conditions and inlet turbulence intensity)on numerical simulation of the VMCT are studied in detail.The findings summarize an effective CFD simulation strategy based on OpenFOAM and provide a valuable reference for future CFD simulations of VMCTs.展开更多
Chloride-induced corrosion of the reinforcement is considered as one of the major mechanisms resulting in the reduction of structural resistance of reinforced concrete structural elements located in marine and other a...Chloride-induced corrosion of the reinforcement is considered as one of the major mechanisms resulting in the reduction of structural resistance of reinforced concrete structural elements located in marine and other aggressive environments. A study of reinforced concrete structures located at the Fangcheng dock in the Beibu Gulf port, China, was present. The result from field survey indicates that the concrete cover depth and chloride diffusion coefficient fit best normal distribution and lognormal distribution, respectively. The service life of structure is about 55 a, while initiation time is 45 a. Sensitivity analysis indicates that the most influential factor of the structure service life prediction is concrete cover, followed by diffusion coefficient, diffusion decay index, critical chloride concentration, surface chloride concentration, current density and localized pitting corrosion. Finally, the effects of diffusion decay index and critical chloride concentration on structure service life prediction are discussed.展开更多
Under the conditions of strong sea clutter and complex moving targets,it is extremely difficult to detect moving targets in the maritime surface.This paper proposes a new algorithm named improved tunable Q-factor wave...Under the conditions of strong sea clutter and complex moving targets,it is extremely difficult to detect moving targets in the maritime surface.This paper proposes a new algorithm named improved tunable Q-factor wavelet transform(TQWT)for moving target detection.Firstly,this paper establishes a moving target model and sparsely compensates the Doppler migration of the moving target in the fractional Fourier transform(FRFT)domain.Then,TQWT is adopted to decompose the signal based on the discrimination between the sea clutter and the target’s oscillation characteristics,using the basis pursuit denoising(BPDN)algorithm to get the wavelet coefficients.Furthermore,an energy selection method based on the optimal distribution of sub-bands energy is proposed to sparse the coefficients and reconstruct the target.Finally,experiments on the Council for Scientific and Industrial Research(CSIR)dataset indicate the performance of the proposed method and provide the basis for subsequent target detection.展开更多
基金supported by the Southwest Institute of Technology and Engineering cooperation fund(Grant No.HDHDW5902020104)。
文摘The ocean is one of the essential fields of national defense in the future,and more and more attention is paid to the lightweight research of Marine equipment and materials.This study it is to develop a Machine learning(ML)-based prediction method to study the evolution of the mechanical properties of Al-Li alloys in the marine environment.We obtained the mechanical properties of Al-Li alloy samples under uniaxial tensile deformation at different exposure times through Marine exposure experiments.We obtained the strain evolution by digital image correlation(DIC).The strain field images are voxelized using 2D-Convolutional Neural Networks(CNN)autoencoders as input data for Long Short-Term Memory(LSTM)neural networks.Then,the output data of LSTM neural networks combined with corrosion features were input into the Back Propagation(BP)neural network to predict the mechanical properties of Al-Li alloys.The main conclusions are as follows:1.The variation law of mechanical properties of2297-T8 in the Marine atmosphere is revealed.With the increase in outdoor exposure test time,the tensile elastic model of 2297-T8 changes slowly,within 10%,and the tensile yield stress changes significantly,with a maximum attenuation of 23.6%.2.The prediction model can predict the strain evolution and mechanical response simultaneously with an error of less than 5%.3.This study shows that a CNN/LSTM system based on machine learning can be built to capture the corrosion characteristics of Marine exposure experiments.The results show that the relationship between corrosion characteristics and mechanical response can be predicted without considering the microstructure evolution of metal materials.
基金Project(ZR2023ME063)supported by the Shandong Provincial Natural Science Foundation,ChinaProject(121311KYSB20210005)supported by the Overseas Science and Education Cooperation Center Deployment Project,ChinaProject supported by the Qingdao Expert Workstation for Intelligent Anticorrosion for Water Diversion Project,China。
文摘Urea,paracetamol and glutamine(based on the expired drugs)were selected as vapor-phase corrosion inhibitors(VCIs)to study their corrosion protection effect on red copper in simulated marine atmospheric environment by using weight loss,electrochemical measurement techniques(specially designed electrochemical testing device for simulating marine atmospheric environments)and surface morphology characterization analysis(SEM/EDS,XRD,RAMAN,XPS).Weight loss results show that the three corrosion inhibitors have good corrosion inhibition effect on red copper,and the corrosion inhibition efficiency in the order of glutamine(83.62%)>urea(68.46%)>paracetamol(61.47%).Surface morphology characterization analysis provides evidence of adsorption of corrosion inhibitors molecules on the red copper surface,thus forming a protective film that blocked the red copper surface from the aggressive chloride ion attack.
基金Zhenjiang City Key R&D Plan Modern Agriculture Project(No.SH2021017)Zhenjiang“Jinshan Talents”Project 2021Jiangsu Province“Six Talent Peak”Program(No.XCL-111)。
文摘Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.
基金Projects(52471096,51971191)supported by the National Natural Science Foundation of ChinaProject(S202410530205)supported by the College Students Innovation and Entrepreneurship Training Program of Hunan Province,ChinaProject(S202310530029)supported by the National College Students Innovation and Entrepreneurship Training Program,China。
文摘The study systematically investigated the impact of zinc sacrificial anode(Zn-SA)cathode protection on the corrosion of X80 steel caused by Desulfovibrio desulfuricans(D.desulfuricans)in a marine tidal environment.Utilizing weight-loss analysis,electrochemical measurements,Raman spectroscopy,and 3D morphology microscopy,the research unveiled significant findings.Unprotected steel suffered pronounced localized corrosion in the presence of D.desulfuricans in the marine tidal environment.However,the implementation of Zn-SA cathode protection notably reduced the activity of both planktonic and sessile D.desulfuricans cells.Over time,the accumulation of calcareous deposits within the corrosion products increased,as evidenced by a rise in the resistance of the corrosion produt film(Rf).Remarkably,Zn-SA cathode protection demonstrated substantial inhibition of the steel’s corrosion rate,albeit exhibiting reduced efficiency as the vertical height of the steel within the tidal environment increased.
文摘Sloshing experiment is crucial to determine the reaction performance of regeneration columns on an offshore floating platform.A novel type of column motion simulating device and a Marine Predator Algorithm-based Sliding Mode Controller(MPA-SMC)are proposed for such sloshing experiments.The simulator consists of a Stewart platform and a steel framework.The Stewart platform is located at the column's center of gravity(CoG)and supported by the steel framework.The platform's hydraulic servo system is controlled by a sliding mode controller with parameters optimized by MPA to improve robustness and precision.A numerical sloshing experiment is conducted using the proposed device and controller.The results show that the novel motion simulator has lower torque during the column sloshes,and the proposed controller performs better than a well-tuned PID controller in terms of target tracking precision and anti-interference capability.
文摘Tibet plateau is a vast hydrocarbon\|bearing region which is the biggest in area, the lowest in exploration and the poorest in knowing, especially, knowing a little for Mesozoic marine petroleum geology problem (particularly for Mesozoic marine source rock) in Chinese land. The research of oil and gas generation for Mesozoic marine source rock have been accomplished on basis of a large number of data for source rock samples appeared on the weather (29 items, about 4000 samples, 23976 sample times and 200000 data) in Tibet Plateau. Full text is composed of following four parts:1\ Regional geology\;Summarized regional geology briefly, emphasized on regional structures, sedimentary facies and stratum characteristics related closely with source rock.
基金National Natural Science Foundation of China(11572094,5171101175,51809083)。
文摘Using the PimpleDyMFoam solver in open-source computing software OpenFOAM,based on the SST k-ωturbulence model and PIMPLE algorithm,a numerical simulation method of vertical-axis marine current turbines(VMCTs)is proposed,and the calculated results are compared with the experimental results.The results show that the numerical simulation method is feasible.Compared with other commercial softwares,this method has the advantages of higher solution efficiency and greater flexibility.According to the needs of users,the solver can be built on the basis of original code,and the corresponding discrete method can be optimized.This method can achieve optimization algorithms,save time and cost,etc.Secondly,the effects of different parameters(mesh density,time step,the selection of sidewall boundary conditions and inlet turbulence intensity)on numerical simulation of the VMCT are studied in detail.The findings summarize an effective CFD simulation strategy based on OpenFOAM and provide a valuable reference for future CFD simulations of VMCTs.
基金Project(41274012) supported by the National Natural Science Foundation of China
文摘Chloride-induced corrosion of the reinforcement is considered as one of the major mechanisms resulting in the reduction of structural resistance of reinforced concrete structural elements located in marine and other aggressive environments. A study of reinforced concrete structures located at the Fangcheng dock in the Beibu Gulf port, China, was present. The result from field survey indicates that the concrete cover depth and chloride diffusion coefficient fit best normal distribution and lognormal distribution, respectively. The service life of structure is about 55 a, while initiation time is 45 a. Sensitivity analysis indicates that the most influential factor of the structure service life prediction is concrete cover, followed by diffusion coefficient, diffusion decay index, critical chloride concentration, surface chloride concentration, current density and localized pitting corrosion. Finally, the effects of diffusion decay index and critical chloride concentration on structure service life prediction are discussed.
基金the National Natural Science Foundation of China(U19B2031).
文摘Under the conditions of strong sea clutter and complex moving targets,it is extremely difficult to detect moving targets in the maritime surface.This paper proposes a new algorithm named improved tunable Q-factor wavelet transform(TQWT)for moving target detection.Firstly,this paper establishes a moving target model and sparsely compensates the Doppler migration of the moving target in the fractional Fourier transform(FRFT)domain.Then,TQWT is adopted to decompose the signal based on the discrimination between the sea clutter and the target’s oscillation characteristics,using the basis pursuit denoising(BPDN)algorithm to get the wavelet coefficients.Furthermore,an energy selection method based on the optimal distribution of sub-bands energy is proposed to sparse the coefficients and reconstruct the target.Finally,experiments on the Council for Scientific and Industrial Research(CSIR)dataset indicate the performance of the proposed method and provide the basis for subsequent target detection.
