The corrosion characteristic and mechanism of Mg-5Y-1.5Nd-xZn-0.5Zr(x=0,2,4,6 wt.%)alloys in marine atmospheric environment

The microstructure and precipitated phases of as-cast Mg-5Y-1.5Nd-x Zn-0.5Zr(x=0,2,4,6 wt.%)alloys were investigated by optical microscopy,scanning electron microscopy,energy-dispersive spectrometry and X-ray Diffraction.The exposure corrosion experiment of these magnesium alloys was tested in South China Sea and KEXUE vessel atmospheric environment.The corrosion characteristic and mechanism of magnesium alloys of Mg-5Y-1.5Nd-x Zn-0.5Zr(x=0,2,4,6 wt.%)alloys were analyzed by weight loss rate,corrosion depth,corrosion products and corrosion morphologies.The electrochemical corrosion tests were also measured in the natural seawater.The comprehensive results showed that Mg-5Y-1.5Nd-4Zn-0.5Zr magnesium alloy existed the best corrosion resistance whether in the marine atmospheric environment and natural seawater environment.That depended on the microstructure,type and distribution of precipitated phases in Mg-5Y-1.5Nd-4Zn-0.5Zr magnesium alloy.Sufficient quantity anodic precipitated phases in the microstructure of Mg-5Y-1.5Nd-4Zn-0.5Zr alloy played the key role in the corrosion resistance.

Corrosion behavior of HVOF Inconel 625 coating in the simulated marine environment

High velocity oxygen fuel(HVOF)spraying process is commonly used to produce superalloy coatings.Inconel 625 coating was prepared on Q235B low carbon steel by HVOF.A series of experiments were conducted to examine the surface and corrosion resistance properties of Inconel 625 HVOF coating.In this paper,potentiodynamic polarization tests and electrochemical impedance spectroscopy(EIS)tests were carried out to evaluate the corrosion resistance of Inconel 625 coating under simulated marine environment.The experiment-al results showed that Inconel 625 coating revealed low porosity and desired coating thickness.Shift in the corrosion potential(E_(corr))to-wards the noble direction combined with much low corrosion current density(i_(corr))indicating a significant improvement of HVOF Inconel 625 coating compared with the substrate.

Predict the evolution of mechanical property of Al-Li alloys in a marine environment

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.

Expired drugs as vapor-phase corrosion inhibitors of copper in simulated marine atmospheric environment

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.

Research on the Relationship between Marine Environment with Seafood Exploitation Productivity and Catch per Unit Effort in the Upwelling Area of the South Central Coast of Vietnam

The analysis of the relationship between oceanographic and environmental factors and fish production and productivity reveals that during the Southwest monsoon season,fish production and productivity are typically higher and more variable compared to the Northeast monsoon season.These metrics exhibit a relatively strong relationship with oceanographic structural variables,with a multiple correlation coefficient of R0=0.56 during the Southwest monsoon season,which decreases to R0=0.4 in the Northeast monsoon season.Specifically,fish production and productivity show a positive correlation with seawater temperature during the Northeast monsoon season,a negative correlation during the Southwest monsoon season,and a negative correlation with salinity in both seasons.Multivariate regression analysis further highlights a significant relationship between marine resource productivity and various oceanographic and environmental factors.Notably,factors such as Tday(Bottom Water Temperature),H0,PHY(Phytoplankton),and ZOO(Zooplankton)demonstrate high pairwise correlation coefficients with fish production and are positively correlated with each other.Additionally,fishing productivity peaks in areas with low flow speeds(20-40 cm/s)and regions characterized by alternating cyclonic and anticyclonic circulations.

Panoptic UAV:Panoptic Segmentation of UAV Images for Marine Environment Monitoring

UAV marine monitoring plays an essential role in marine environmental protection because of its flexibility and convenience,low cost and convenient maintenance.In marine environmental monitoring,the similarity between objects such as oil spill and sea surface,Spartina alterniflora and algae is high,and the effect of the general segmentation algorithm is poor,which brings new challenges to the segmentation of UAV marine images.Panoramic segmentation can do object detection and semantic segmentation at the same time,which can well solve the polymorphism problem of objects in UAV ocean images.Currently,there are few studies on UAV marine image recognition with panoptic segmentation.In addition,there are no publicly available panoptic segmentation datasets for UAV images.In this work,we collect and annotate UAV images to form a panoptic segmentation UAV dataset named UAV-OUC-SEG and propose a panoptic segmentation method named PanopticUAV.First,to deal with the large intraclass variability in scale,deformable convolution and CBAM attention mechanism are employed in the backbone to obtain more accurate features.Second,due to the complexity and diversity of marine images,boundary masks by the Laplacian operator equation from the ground truth are merged into feature maps to improve boundary segmentation precision.Experiments demonstrate the advantages of PanopticUAV beyond the most other advanced approaches on the UAV-OUC-SEG dataset.

Effect of cathode protection on Desulfovibrio desulfuricans corrosion of X80 steel in a marine tidal environment

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.

Impact of ocean data assimilation on the seasonal forecast of the 2014/15 marine heatwave in the Northeast Pacific Ocean

A remarkable marine heatwave,known as the“Blob”,occurred in the Northeast Pacific Ocean from late 2013 to early 2016,which displayed strong warm anomalies extending from the surface to a depth of 300 m.This study employed two assimilation schemes based on the global Climate Forecast System of Nanjing University of Information Science(NUIST-CFS 1.0)to investigate the impact of ocean data assimilation on the seasonal prediction of this extreme marine heatwave.The sea surface temperature(SST)nudging scheme assimilates SST only,while the deterministic ensemble Kalman filter(EnKF)scheme assimilates observations from the surface to the deep ocean.The latter notably improves the forecasting skill for subsurface temperature anomalies,especially at the depth of 100-300 m(the lower layer),outperforming the SST nudging scheme.It excels in predicting both horizontal and vertical heat transport in the lower layer,contributing to improved forecasts of the lower-layer warming during the Blob.These improvements stem from the assimilation of subsurface observational data,which are important in predicting the upper-ocean conditions.The results suggest that assimilating ocean data with the EnKF scheme significantly enhances the accuracy in predicting subsurface temperature anomalies during the Blob and offers better understanding of its underlying mechanisms.

Research on the Construction of Intellectual Property System and Optimization of Business Environment in China

With the rapid development of globalization and information technology,intellectual property has been one of the key drivers of economic growth,and the construction of intellectual property system has become an important criterion for measuring the quality of business environment.This article is intended to explore the current status of intellectual property system construction in China,the challenges,and its relationship with the business environment,to propose the corresponding countermeasures and suggestions.The study finds that the legal system of intellectual property in China is gradually improving,and judicial and administrative protection are continuously strengthened.However,the challenges still remain such as frequent infringements,rights hard to protect and insufficient international cooperation.These issues not only affect the legitimate rights and interests of innovation entities,but also for the market fairness and the level of the business environment.Therefore,this article proposes that strengthening the perfection of the intellectual property legal system,enhancing intellectual property services and support capabilities,strengthening international cooperation and exchanges,and accelerating the cultivation of composite talents.It aims to provide theoretical references for the construction of intellectual property system and the optimization of the business environment,promote the high-quality development of economy and enhance the global competitiveness of the country.

Obtaining Electromagnetic Properties of Multi-Type Media in Realistic Environments:State-of-the-Art and Prospects

To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study.

Influence of Corrosion on the Reliability of SMA Materials in the Marine Environment

The research of new materials on the basis of memory shape today occupies the special attention of researchers in various industrial fields,such as medicine,traffic,robotics,etc.This paper analyzes the possibility of applying SMAs(shape memory alloys)in the maritime industry in terms of monitoring the behavior of SMAs in different marine environments.The subject of the research is Cu-Al-Ni and Ni-Ti CC alloys processed by CC(continuous casting)in the shape of bars and Ni-Ti as cast processed by casting in the shape of disk.Using the method of EDX(energy dispersion X-ray spectrophotometry),the chemical composition of alloy elements in zones such as in the air,on the surface of the sea and in the sea was determined after six and twelve months of exposure.By applying the theory of reliability,an assessment of the reliability of the alloy elements was obtained.According to the obtained results of the Cu-Al-Ni alloy,nickel is the most reliable in the sea.Aluminum is the least reliable in the sea.The Ni-Ti CC alloy in the marine environment is more reliable than the Ni-Ti as cast alloy.Based on the changes in the chemical composition of alloys in all three considered zones,it is concluded that all three alloys have the lowest reliability in the sea and the highest in the air.

Web-based spatiotemporal visualization of marine environment data

With long-term marine surveys and research,and especially with the development of new marine environment monitoring technologies,prodigious amounts of complex marine environmental data are generated,and continuously increase rapidly.Features of these data include massive volume,widespread distribution,multiple-sources,heterogeneous,multi-dimensional and dynamic in structure and time.The present study recommends an integrative visualization solution for these data,to enhance the visual display of data and data archives,and to develop a joint use of these data distributed among different organizations or communities.This study also analyses the web services technologies and defines the concept of the marine information gird,then focuses on the spatiotemporal visualization method and proposes a process-oriented spatiotemporal visualization method.We discuss how marine environmental data can be organized based on the spatiotemporal visualization method,and how organized data are represented for use with web services and stored in a reusable fashion.In addition,we provide an original visualization architecture that is integrative and based on the explored technologies.In the end,we propose a prototype system of marine environmental data of the South China Sea for visualizations of Argo floats,sea surface temperature fields,sea current fields,salinity,in-situ investigation data,and ocean stations.An integration visualization architecture is illustrated on the prototype system,which highlights the process-oriented temporal visualization method and demonstrates the benefit of the architecture and the methods described in this study.

Risk Assessment of Marine Environments Along the South China Sea and North Indian Ocean on the Basis of a Weighted Bayesian Network

Marine environments have a considerable influence on the construction of the Chinese 21st Century Maritime Silk Road.Thus,an objective and quantitative risk assessment of marine environments has become a key problem that must be solved urgently.To deal with the uncertainty in marine environmental risks caused by complex factors and fuzzy mechanisms,a new assessment technique based on a weighted Bayesian network(BN)is proposed.Through risk factor analysis,node selection,structure construc-tion,and parameter learning,we apply the proposed weighted BN-based assessment model for the risk assessment and zonation of marine environments along the Maritime Silk Road.Results show that the model effectively fuses multisource and uncertain envi-ronmental information and provides reasonable risk assessment results,thereby offering technical support for risk prevention and disaster mitigation along the Maritime Silk Road.

Structural strength deterioration of coastal bridge piers considering non-uniform corrosion in marine environments

In the aggressive marine environment over a long-term service period,coastal bridges inevitably sustain corrosion-induced damage due to high sea salt and humidity.This paper investigates the strength reduction of coastal bridges,especially focusing on the effects of non-uniform corrosion along the height of bridge piers.First,the corrosion initiation time and the degradation of reinforcement and concrete are analyzed for bridge piers in marine environments.To investigate the various damage modes of the concrete cover,a discretization method with fiber cells is used for calculating time-dependent interaction diagrams of cross-sections of the bridge piers at the atmospheric zone and the splash and tidal zone under a combination of axial force and bending moment.Second,the shear strength of these aging structures is analyzed.Numerical simulation indicates that the strength of a concrete pier experiences dramatic reduction from corrosion initiation to the spalling of the concrete cover.Strength loss in the splash and tidal zone is more significant than in the atmospheric zone when structures’service time is assumed to be the same.

Measuring Chinese Marine Environmental Efficiency:A Spatiotemporal Pattern Analysis

Environmental efficiency standards are often used to evaluate the costs of oceanic economic development. A variety of statistical analyses were applied in this study to quantify the marine environmental efficiency of 11 Chinese coastal provinces and municipalities between 2000 and 2014. Results initially reveal that environmental efficiency measures that incorporate undesirable outputs are more consistent with real production conditions and thus the use of marine economic and environmental efficiencies supplement and complement one another. Second, overall marine environmental efficiency across China tends to be low and can be spatially characterized by a transformation such that the inefficiencies noted in 2000 have subsequently been transformed to comprise a three-tiered structure that encompasses northern, central, and southern cores. Third, variation in absolute and relative marine environmental efficiency differences for the coastal regions of China have been consistent over time; values initially decreased before increasing again in a fluctuating manner over the time period of this analysis. Fourth, data show that the Pearl River Delta area has experienced the highest rate of change in marine environmental efficiency over time when economic zones are used as basic research units, although values have nevertheless fluctuated significantly. Fifth, values for total factor productivity as well as technical efficiency and change across the Chinese marine economy all fluctuated over time but increased. Data show that changes in marine environmental efficiency across China can primarily be attributed to progress in marine science and technology. Finally, levels of capital investment and marine industrial pollution intensity are not significantly correlated with marine environmental efficiency. Indeed, both marine industrial structural levels and environmental protection technologies have had a positive effect on environmental efficiency while levels of investment in marine scientific research as well as the scale of economic development, the marine economy, and the degree of external openness have all exerted negative effects on this key variable.

Reliability-based service life prediction of existing concrete structures under marine environment

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.

Degradation and Mechanism of the Mechanics and Durability of Reinforced Concrete Slab in A Marine Environment

An experimental research was conducted to determine the corrosion and bearing capacity of a reinforced concrete（RC） slab at different ages in a marine environment.Results show that the development of corrosion-induced cracks on a slab in a marine environment can be divided into three stages according to crack morphology at the bottom of the slab.In the first stage,cracks appear.In the second stage,cracks develop from the edges to the middle of the slab.In the third stage,longitudinal and transverse corrosion-induced cracks coexist.The corrosion ratio of reinforcements nonlinearly increases with the age,and the relationship between the corrosion ratio of the reinforcements and the corrosion-induced crack width of the concrete is established.The flexural capacity of the corroded RC slab nonlinearly decreases with the age,and the model for the bearing capacity factor of the corroded RC slab is established.The mid-span deflection of the corroded RC slab that corresponds to the yield of the reinforcements linearly increases with the increase in corrosion ratio.Finally,the mechanisms of corrosion morphology and the degradation of the mechanical properties of an RC slab in a marine environment are discussed on the basis of the basic theories of steel corrosion in concrete and concrete structure design.

Methods Used to Study Bacterial Diversity in the Marine Environment around Qingdao

Pollution has a considerable effect on biological communities, in terms of size and diversity of the populations. Yet, the precise consequences of human activity on microbial communities in the marine environment are poorly understood. Therefore, in an ongoing collaborative research programme between Heriot-Watt University and the Ocean University of Qingdao, bacteria were isolated in 1999 and 2000 from marine sediment, seawater, seaweed, fish and shellfish, taken from locations in Shandong Province adjacent to Qingdao. Sampling locations were comprised of industrial and aquacultural sites and a clean, control site. In order to analyse microbial diversity, a polyphasic approach was adopted for characterisation of these isolates, specifically through examination of key phenotypic traits, i.e. using Biolog GN MicroPlate TM profiles, bacterial whole cell protein profiles and 16S and 23S rRNA gene sequences. These techniques yielded complex taxonomic data, which were subjected to statistical and cluster analyses. The application of these methods to studies of microbial communities is discussed.

Modeling Boundary and Edge Effect of Chloride Diffusion for Durability Design of Concrete Structures Exposed in Marine Environment

According to the Fick＇s second law of diffusion, six analytical solutions of chloride profile in concrete were studied and discussed with regard to different boundary and initial conditions. In those analytical solutions, the most prevailing error-function solution which is based on semi-infinite assumption is the simple one, but may under-estimate the chloride content in concrete and over-rate the life time prediction of concrete structures. The experimental results show that compared with other solutions, the chloride content in concrete predicted by error-function model is the minimum, and the calculation difference produced by different analytical models should not be ignored. The influence of models on chloride content prediction is more than other environment and material coefficients in some time. In order to get a more realistic prediction model, modification to error-function model is suggested based on analysis and calculation examples concerning the boundary and edge effect.

Problems of Marine Ecological and Environmental Compensations of Oil Spill in China

In recent years, the frequent occurrences of marine oil spills have already become one of the major reasons threatening the marine ecological safety of China. In the event of oil spill, oth-er than taking the necessary emergent measures aiming specifically at the damage to the marine ecology and environment, using legal means to assure that the damage liabilities are borne by the respon-sible persons to protect the national interests are also very neces-sary. This paper advances five recommendations regarding the development of a system for ecological legal compensations from the standpoint of the current status of legislation and execution of the laws on compensation of oil spill polluting marine ecosystem. These five recommendations include: determination of the status of juristic action in marine ecological and environmental compen-sations in accordance with the laws, determination of plaintiff of marine ecological and environmental compensations in accordance with the laws, determination of the four basic principles in the le-gal actions of marine ecological and environmental compensations in accordance with the laws, determination of assessment technical standard of marine ecological and environmental damages in ac-cordance with the laws, and determination of the scope of marine ecological and environmental compensations in accordance with the laws.