Marine Field Research Articles

Origin of chamosite and berthierine: Implications for volcanic-ash-derived Nb-Zr-REY-Ga mineralization in the Lopingian sequences from eastern Yunnan, SW China

Clay minerals are generally used as pivotal indicators to reveal diagenetic parameters such as temperature and pH in hydrothermal ore-forming systems. Within the Late Permian Nb-Zr-REY-Ga-mineralized horizons in eastern Yunnan, the elevated enrichment of critical metals has been considered to be closely associated with abundant clay minerals. In this paper, the identification, abundance, morphology, modes of occurrence, and chemical compositions of two phyllosilicate minerals, namely chamosite (chlorite group) and berthierine (serpentine-kaolinite group) were analyzed by XRD (X-ray diffraction) and SEM-EDS (scanning electron microscopy equipped with an energy dispersive X-ray spectrometer). The results show that chamosite mainly occurs as massive and book-like aggregates, while berthierine occurs in various forms, including coarse granular, spherulitic, sheaf-like, sharp-angular, and vermicular aggregates. The modes of occurrence and scatter plots of Mg/(Mg + Fe) vs. Al/(Al + Fe + Mg) of chamosite indicate a Fe-Mg-rich siliceous hydrothermal origin. In the Al/Si-Mg/Fe diagram, analysis points for berthierine are distributed in the partially overlapping fields of hydrothermal ore, laterite/bauxite, and marine, indicating that the formation of berthierine was influenced by various geological factors. Based upon its chemistry and modes of occurrence, berthierine mainly originated by direct precipitation from Fe-Mg-rich siliceous hydrothermal fluids, but in some cases, it was derived from the replacement of precursor minerals and the in-situ alteration of volcanic fragments. A scenario of the transformation mechanism of clay minerals in the Nb-Zr-REY-Ga-rich horizons is proposed. Airborne volcanic glasses and primary minerals were initial altered in-situ into vermicular kaolinite and angular berthierine in the early diagenetic stage. Subsequently, some vermicular kaolinite and the oolitic berthierine crystallized from solutions underwent gradual illitization, and some pre-existing minerals (e.g., albite, kaolinite, and illite) were altered into berthierine, while a proportion of chamosite transformed from berthierine through an interstratified berthierine/chamosite (B/C) in the middle to late diagenetic stages. Throughout all stages of diagenesis, the chamosite, berthierine, and their intermediate phases precipitated directly from Fe-Mg-rich siliceous hydrothermal fluids. Moreover, the diagenetic temperature revealed by chamosite is from ∼200 to ∼302℃, indicating that the Nb-Zr-REY-Ga mineralization and chamosite formation occurred under low-temperature thermal alteration conditions.

A Study on the Efficient Method of Underwater Welding Education for Commercial Diver

Although the requirements of underwater welding has been increasing in the marine field, limited studies have been conducted on the systematic approaches for underwater welding education. The present study was conducted to provide baseline data to understand the educational underwater welding process for commercial diving candidates. For this, optimal welding parameters for underwater were configured, experimental welding dives were conducted, and weld coupons were inspected and analyzed.</br>The results of this study can be summarized as follows respective weld passes. In the root pass, the insufficient weld deposit sizes owing to the fast weld speed were the main defects. In the second pass, non-paralleled beads and insufficient weld convexity were the main defects. In the third pass, incomplete deposit between the beads and the unplaned weld surface were the main defects. Finally, macro-etching test revealed incomplete penetration, slag inclusion, undersize of weld and unplaned weld profile.</br>The aforementioned weld defects must be reduced for beginner welder divers, selecting welding parameters such as suitable amperage, accurate work angle, and weld speed as the main variables.

Fabrication of Lightweight Polyimide Foams with Exceptional Mechanical and Thermal Properties.

Lightweight polyimide foams (PIFs) with exceptional thermal resistance and compressive properties arefabricated by heating polyester ammonium salts (PEASs) which areprepared by copolymerizing 4, 4'-diaminobenzanilide (DABA), 4, 4'-diaminodiphenyl methane (MDA) and 3, 3', 4, 4'-benzophenone tetracarboxylic dianhydride (BTDA). Hydrogen bonds areformed between CONH and CO in the PI chains due to the addition of DABA and the melt viscosity of PEAS precursors increase with increasing content of DABA, which isadvantageous to bind the foaming gases for cell expansion. The expansion ratio of PEAS precursors isincreased from 633% to 1133% when the molar ratio of MDA/DABA ischanged from 10:0 to 6:4. The compressive strength and modulus of PIFM9D1 (i.e., the molar ratio of MDA/DABA is9:1, foam density: 120.8 kg m-3 ) reach as high as 0.59 and 15.0MPa, respectively. The PIFs possess prominent thermal performance with the initial thermal degradation temperatures (under both nitrogen and air atmosphere) and glass transition temperatures (as assessed by DSC and DMA) exceeding 511 and 292°C, respectively. The thermal conductivity of PIFs islower than 0.049 W m-1 K-1 , which exhibits promising applications for serving as high-temperature thermal insulation materials in the fields of aerospace, marine, and nuclear sectors among others.

Data and domain knowledge dual‐driven artificial intelligence: Survey, applications, and challenges

AbstractAt present, the mainstream mode of machine learning algorithms is the data‐driven method, which mainly relies on the self‐learning ability of deep neural networks and continuously evolving models in data‐driven training. However, the pure data‐driven method has some critical problems, such as high data collection cost, poor interpretability and easy to be be disturbed by noise. Although the knowledge‐driven method has high stability, it lacks self‐learning and evolution ability in the face of comprehensive and complex problems. In recent years, the convergence of data and domain knowledge has combined the advantages of both learning paradigms. One typical way is to embed domain knowledge into the data‐driven model to improve the interpretability of the model, and then use the self‐learning ability of the data‐driven model to explore knowledge, and continuously iterate the domain knowledge to form a closed loop. The data‐knowledge dual‐driven methods have brought transformative innovations in machine learning. This review first introduced the advantages and necessity of the data‐knowledge dual‐driven model in the field of artificial intelligence. Then, the applications of the data‐knowledge dual‐driven model in the smart marine field were introduced. Finally, the challenges and trends of the data‐knowledge dual‐driven artificial intelligence are anticipated.

Electrical and thermal performance of multidimensional semi-transparent CdTe PV window on offshore passenger ships in moored and sailing condition

Utilizing solar energy is an effective method to decrease fossil energy consumption in marine field. Horizontally installed deck photovoltaic (PV) systems have been widely investigated to reduce navigation energy consumption on ocean-going ships. However, energy saving rate is unsatisfactory because of the low energy density of solar energy and the shadow caused by ship body. As for large amount of offshore small ships, it's even harder to utilize the existing technology since deck space is limited. In this paper, semi-transparent CdTe PV window system is proposed for offshore passenger ships without enough deck spaces but with large window area around ship cabin. Multidimensional PV windows can increase PV area and reduce heat gain inside the cabin, shadow effect caused by ship body is also avoided. Energy saving can be both achieved by electrical generation actively and cooling load reduction passively. Dynamic mathematical models of multidimensional PV window under moored and sailing conditions are established. Simulation results indicate that the daily electrical generation and average electrical efficiency are 0.74 kWh & 14.65% in moored condition and 0.83 kWh & 16.24% in sailing condition. Navigation leads to higher received solar radiation (18.2%), higher electrical generation (12.1%) and higher electrical efficiency (10.85%). Electricity created by PV window can support 6 h' continuous operation for auxiliary system on board. With PV windows, the average air temperature in cabin is decreased by 6.5 °C compared with ordinary windows. The average heat fluxes through four directions of PV windows are decreased by 75.44%, 73.64%, 47.52% and 75.33% compared with ordinary windows.

Design of Microbial Corrosion Assessment Model for Protective Coatings based on Combined Weight TOPSIS

Instrumentation has a wide range of applications in various fields. In today’s rapid development of information technology and the economy, it plays an indispensable role. The application environment of instrumentation in many fields is complex and harsh. Therefore, the requirements for instrumentation materials are also more stringent. This paper mainly focuses on the special fields of aerospace, petrochemical, marine, and nuclear energy. The application status of instrumentation and its harsh application environment have been researched. This paper researched the main corrosion failure modes of instrumentation materials, and put forward suggestions and solutions for corrosion protection methods.

Experimental Investigation on Thermal Behaviour of Silicon Carbide (SiC) based Polymer Composites under Hygrothermal Conditions

The thermal management of electronic devices is a critical component of their performance. Due to the emergence and evolution of new technologies, the wide use of electronic devices is increased in the past decade in the field of marine, automobile and other stationary applications. The need for effective thermal management in these applications has become more critical. This paper aims to provide a comprehensive overview of the various challenges that face the development of new composite materials, as epoxy-based composites are the latest trend of materials widely used in many areas. But their thermal conductivity behaves poorly in moisture and thermal conditions. This work attempts to study the behaviour of silicon carbide and E glass fiber reinforced polymer matrix composite under hygrothermal and compressive loads. Specimens are also tested for moisture absorption to calculate the hygro strains of a specimen. E-glass fiber is fixed to 15% and varied 10%, 20% and 30% of SiC in the fabrication of hybrid polymer composite using the hand-layup technique. These specimens undergo tensile, flexural, hardness and thermal conductivity tests, revealing the tensile strength, thermal, flexural strength, hardness and thermal conductivity of proposed specimens. The behaviour of the specimens is compared for all conditions with moisture at room temperature, 80 deg C and 150 deg C.

Novel feature extraction of underwater targets by encoding hydro-acoustic signatures as image

Underwater vessel-radiated acoustical noise (UVRAN) is a major factor for classification in the sea by the SONAR. Due to unsteady and complex maritime ambient, analyzing underwater sound signals is a challenging issue that has lately received attention in the marine field. In the conventional feature extraction methods, to reduce the effect of ocean noise, the de-noising procedure is performed before complexity measurement by mode decomposition techniques. Based on this, we propose a novel insight for the first time to distinguish the objects which made the underwater noises as the hydro-acoustic signature, using a signals-to-image conversion without noise removal. After pre-processing, the spectral amplitude mean difference function is encoded into an image using Gramian angular field (GAF) technique. Subsequently, image texture analysis is performed in which GAF images are subjected to the gray-level co-occurrence matrix (GLCM). Finally, the second-order image statistic (i.e., 2-D permutation entropy) is calculated. Compared with other methods, results demonstrate that the proposed method has a high degree of separation and stability between the various kinds of underwater targets, suggesting that the methodology is superior to the existing methods. Moreover, our model is robust to noise. The approach perhaps opens an alternative path for UVRAN discrimination.

ALTERNATIF KELEMBAGAAN KEMITRAAN BAGI PEMBERDAYAAN NELAYAN PERIKANAN TANGKAP DI KOTA AMBON

The availability of potential fishery resources owned by the waters around Ambon Island has not been fully supported by the ability of human resources to manage them properly. The mastery of technology and management in the field of fisheries and marine owned by coastal communities in Ambon is still limited to be able to utilize the potential of fisheries and marine resources available. On the other hand, the availability of capital to stimulate economic activities in the fisheries and marine sector has also not been fully met. The mastery of knowledge and business skills of the people living on the coast of Ambon is still traditional and subsistence in nature, so efforts are still needed to increase the productivity of businesses owned by the community. From the description of the conditions in the Ambon area, the presence of partnerships initiated by the government or the private sector is urgent in the framework of empowering fishing communities in this region. This study aims to formulate an alternative framework of partnership institutions that are appropriate for the empowerment of capture fishermen in Ambon. The research method used case study method, data collection using focus group discussion method. Data analysis uses a qualitative descriptive approach. The output of this research is an alternative framework of capture fisheries partnership institutions where in building a partnership concept that can accommodate the aspirations of the community, it is necessary to study the potential of the community itself, both human capital, natural capital, and social capital, coupled with a proper understanding of the problems faced by the fishing community itself, so that the partnership that is built is right on target, which in turn can provide adequate results.

Balanced Scorecard Analysis as An Alternative Management Performance Measuring Tool: Case Study

The aim of this research is to analyze the performance of the Vocational Education Quality Assurance Development Center in the field of Marine, Fishery, Information and Communication Technology using the Balance Scorecard Perspective approach which analyzes four perspectives; financial, customer (in this case educators and education staff), internal business processes, and learning and growth. The research method was carried out qualitatively. The sample in this research is the financial report of the Center for Vocational Education Quality Assurance Development in the Maritime, Fishery, Information and Communication Technology sector (BPPMPV KPTK).

Research on risk Assessment and decision support for underwater Platform in Naval Battle field environment

Autonomous underwater unmanned platforms have become important facilities in the marine field since countries attach importance to maritime rights and interests, and play an important role in both military and civilian use. However, complex underwater marine environmental elements will have a huge impact on the performance of underwater unmanned platforms, and how to ensure the safe and stable operation of underwater unmanned platforms has become an urgent problem to be solved. Based on this practical problem, this paper studies the influence of marine environmental elements on the operation of underwater unmanned platforms with reference to the hydrological data of the South China Sea, and uses Bayesian methods to carry out risk zoning of the impact of the marine environment in the South China Sea on underwater unmanned platforms.

Semantic relations in the terminology field of marine engineering. Polysemy

The present article aims at analysing the cases of terminological polysemy in the field of marine engineering both in the English and the Bulgarian terminological systems. Although it has generally been assumed that a single term should correspond to a single concept, so that a clear and unambiguous communication is ensured, the research results prove that in practice this is far from being the case. The instances analysed are excerpted from corpus materials consisting of specialized and general language dictionaries as well as specialized scientific texts intended for students and professionals in the field. The comparative study results show that in both languages polysemantic terms can arise as a result of their interaction with words belonging to the general language or they can be motivated by a metonymic or metaphoric transfer within the given specialized language. A broad-based theoretical background has been presented and instantiations of all these types of polysemantic terms as well as their explanations have also been included in order to reveal a detailed account on the particularities of terminological polysemy in the field of marine engineering.

Synergistic antifouling behaviors between zwitterions and ZnO nanoparticles in moisture-curable polyacrylate coatings

The current zwitterionic antifouling (AF) coatings generally have limited broad-spectrum AF ability, poor compatibility with coating matrixes and weak mechanical properties due to high water adsorption. In this work, we tried to incorporate zwitterionic component, namely, (N-methoxyacylethyl)-3-aminopropyltriethoxysilane (MAPS) and ZnO nanoparticles into a moisture-curable polyacrylate (MCP) to fabricate marine AF coatings. AF behaviors were examined by laboratory and field assays towards different target foulants. Laboratory anti-protein ability towards bovine serum albumin promoted with the increase of MAPS and/or ZnO contents, verifying their synergistic AF effect towards the earliest pollutant in biofouling process. Laboratory AF test towards bacterium Pseudoalteromonas marina and diatom Cylindrotheca closterium also exhibited the synergistic AF effect between zwitterions and ZnO nanoparticles, however, depending on their concentrations. Under the highest contents of MAPS (i.e., 30 %) and ZnO nanoparticles (i.e., 50 %), the coatings showed the best laboratory AF properties, with the antibacterial rate, sterilization rate and anti-diatom rate of 86.7 %, 71.8 % and 87.6 %, respectively. As for the marine field AF performance, the ZnO nanoparticles content had a significant effect on improving the field antibacterial ability, while the effect of MAPS was not obvious. But for the field anti-diatom assay, MAPS and ZnO nanoparticles depicted synergistic effect on diatom resistance. After field exposure for 52 d, the coatings with 30 % MAPS and 50 % ZnO nanoparticles revealed the best comprehensive AF performance, i.e., 82.4 %, 95.0 % and 95.5 % reductions towards bacteria, diatoms and mussels, respectively, and moreover, maintained pencil hardness of 2 H after immersed in ASW for 9 months. Besides, the coatings were capable of restoring their original oleophobicity and AF capability after mechanical abrasion.

Thickness variation effect on compressive properties of ultra-thick CFRP laminates

As ultra-thick laminates are widely used in the field of aerospace and marine as the main load-bearing structure, extreme service conditions lead to increasing thickness of composite structures. However, the effect of the increase in thickness on the compressive properties of ultra-thick laminates is still unclear. Herein parameters including fiber volume fraction, fiber waviness, void content and free edge effect that affect the compressive strength with increasing thickness are studied. The results show that the fiber volume fraction of ultra-thick laminates does not change significantly with the increase of thickness due to the adoption of the zero-bleeding process, while the fiber waviness and void contribute to the thickness effect on compressive strength. On the other hand, the high interlaminar stress of the free edge contributes to the premature delamination of the specimen, which dominates the compressive strength of the ultra-thick laminate. Finally, compared with the thin laminate (2 mm), the compressive strength of ultra-thick laminate drops sharply (nearly 28%), but when the thickness increases from 30 to 70 mm, the drop of compressive strength is not obvious (only 10%). When the material and curing process are consistent, the weak interlaminar properties of ultra-thick laminates does not change significantly with the increase of thickness, which leads to the insignificant decrease in compression strength of ultra-thick laminates with the increase of thickness. The proposed empirical relationship between the compressive strength and thickness of quasi-isotropic laminates can provide important theoretical basis and experimental reference for the design of ultra-thick composite structures.

Dynamic mechanical properties of nanoparticle-enhanced aluminum alloys fabricated by arc-directed energy deposition

The nanoparticle-enhanced aluminum alloys fabricated by arc-directed energy deposition (Arc-DED) have gained much attention due to their improved microstructure and enhanced mechanical properties, and are expected to be applied in aerospace, defense, and marine fields. The dynamic properties of nanoparticle-enhanced aluminum alloys are required in the aforementioned fields. In this work, the dynamic behaviors of AA7075 and TiC/AA7075 samples fabricated by Arc-DED in as-built and heat-treated states are investigated by Split-Hopkinson pressure bars tests with the strain rates of 2000–5000 s−1 at room temperature. The results show that adding TiC nanoparticles improve the dynamic properties of aluminum alloys, especially their performance after heat treatment. The improved performance can be attributed to the refined grain and the generated strengthening phase. The metallographic structure shows that the adiabatic shear band (ASB) is first generated with an increase in the strain rate. Then, cracks appear along ASB, leading to the final shear failure. A modified Johnson-Cook constitutive model is proposed based on the strain softening and strain rate softening effects. The results obtained by the proposed model agree with the experimental results. This work is the first to study the dynamic behavior of aluminum alloys fabricated by Arc-DED, which has potential value for applicating aluminum alloys in various industries.

Effect of Hull and Propeller Roughness during the Assessment of Ship Fuel Consumption

The effects of hull and propeller roughness are presented over ten years of operation on ship performance. The developed model used in this study is a combination of NavCad and Matlab to perform the resistance and propulsion computations of the selected ship as well as the processing of input and output data. By considering the ship hull, the engine installed and an optimized propeller, the ship performance is computed for a different combination of hull and propeller roughness according to the ITTC recommendations and the opinion of experts in the marine field. Twelve cases are simulated over the selected years of operations and compared to the new ship performance. The hull roughness has the dominant effect on the performance of the ship due to its large area. However, by adding the effect of propeller roughness, an increment is noticed in the loading ratio and fuel consumption by 1–4% and 2–4%, respectively, in addition to the hull roughness. From this study, it is concluded that the roughness of both the hull and propeller is important consider to achieve more accurate results than just considering the hull roughness.

Extensive prokaryotic maintenance respiration in the sea influenced by osmoregulation

Microbial respiration is the major process consuming oxygen in the biosphere. The relative energy demand from growth of biomass or maintenance activities determines the regulation of respiration with impact on how the development of hypoxia and CO2 emissions is controlled. This coupling is crucial for understanding the life history and associated ecological interactions of microorganisms. However, the knowledge of rate and regulating factors of maintenance respiration in the biosphere is limited. In this study, we demonstrated significant relationships in marine field samples where the prokaryotic specific growth rate predicts cell-specific respiration, in accordance with theory from culture models, over a 10-fold salinity range. This enables the first reported direct estimates of maintenance respiration in nature to show a 6-fold variation between 0.12-0.62 fmol O2 cell-1 d-1, comprising 29-72% of prokaryotic specific respiration. The lowest maintenance respiration occurred at salinity close to physiological osmolarity, suggesting osmoregulation as one of the more energy-consuming maintenance activities. A conservative global estimate of maintenance respiration accounted for 66% of the total prokaryotic respiration in the ocean´s mixed layer. This means that maintenance activities dominate the use of the energy generated by prokaryotic respiration in the sea, where osmoregulation is one significant energy consumer. Consequently, maintenance respiration and its regulation must be included in ecological and biogeochemical models to accurately project and manage the development of hypoxia and CO2 emissions from the ocean.

Hydrogel-Anchored Fe-Based Amorphous Coatings with Integrated Antifouling and Anticorrosion Functionality.

Biofouling and corrosion of underwater equipment induced by marine organisms have become major issues in the marine industry. The superior corrosion resistance of Fe-based amorphous coatings makes them suitable for marine applications; however, they have a poor antifouling ability. In this work, a hydrogel-anchored amorphous (HAM) coating with satisfactory antifouling and anticorrosion performance is designed, utilizing an interfacial engineering strategy involving micropatterning, surface hydroxylation, and a dopamine intermediate layer to increase the adhesion strength between the hydrogel layer and the amorphous coating. The as-obtained HAM coating exhibits exceptional antifouling properties, achieving 99.8% resistance to algae, 100% resistance to mussels, and excellent biocorrosion resistance against Pseudomonas aeruginosa. Antifouling and anticorrosion performance of the HAM coating was also explored by conducting a marine field test in the East China Sea, and no signs of corrosion and fouling are observed after 1 month of immersion. It is revealed that the outstanding antifouling properties stem from the killing-resisting-camouflaging trinity that resists organism attachment across different length scales, and the excellent anticorrosion performance originates from the remarkable barrier of the amorphous coating against Cl- ion diffusion and microbe-induced biocorrosion. This work presents a novel methodology for designing marine protective coating with excellent antifouling and anticorrosion properties.

Resource Constraints and Economic Growth: Empirical Analysis Based on Marine Field

To explore the contribution of marine resources to marine economic growth, this study uses panel data from 2006–2019 across 11 coastal provinces and cities in China and establishes threshold regression models using marine capital, labor, and science and technology as threshold variables affecting marine resources and economic growth. The findings reveal that the impact of marine resources on marine economic growth only demonstrates a single threshold effect under the primary industry marine resources; in general, with increased capital investment, the marine economy presents a positive development trend. The impact of primary and secondary marine resources on marine economic growth has a single threshold effect of labor input, while the impact of tertiary marine resources on marine economic growth has a double threshold effect of labor input. With investment in marine science and technology, marine resource development and utilization in the primary industries have played a consistent role in promoting marine economic growth. However, the impact of this role is gradually decreasing; marine resource development and utilization in the secondary and tertiary industries shows a development pattern wherein the driving effect of marine economic growth is first large, then small, and then large again. Based on the above analysis, China should promote the transformation of labor-intensive to capital-intensive industries by increasing investment in marine capital, training marine talent, and developing marine science and technology innovation to increase the development level of China’s marine economy.

Keberlanjutan Pembangunan Wilayah Pesisir di Kabupaten Trenggalek

The coastal area is an area that has the potential to be developed, but the coastal area must also be conserved by making efficient use of coastal resources and utilizing the function of the area in a planned and rational manner, including at Prigi Beach in Watulimo District, Trenggalek Regency. The strategy for developing coastal areas in Trenggalek Regency has been stated in Regional Regulation Number 15 of 2012 concerning Spatial Planning of Trenggalek Regency for 2012-2032. This study uses a qualitative method with a case study approach in an effort to understand the sustainability of coastal development in Trenggalek Regency. Data were obtained through observation, documentation, and interviews with the head of Bappeda (Regional Development Planning Agency of Trenggalek Regency) and the community around Prigi Beach, Trenggalek Regency. Data analysis techniques with interactive models are data collection, data condensation, data presentation and conclusion drawing. Aspects of sustainable development in Watulimo District, Trenggalek Regency include (1) ecology, the existence of Prigi Bay provides benefits in the fields of Tourism, Fisheries and Marine, namely Prigi Beach, Damas Beach, Cengkrong Beach, Mangrove Tourism Forest, Karanggongso White Sand Beach and Pearl Beach. (2) the economy, the low income of fishermen in Prigi is also influenced by natural conditions, so that the fishing process cannot take place throughout the year and (3) social, the fishermen community empowerment program in Prigi has been implemented by the Government to improve the fishing community but the program has not running optimally.