Marine Field Research Articles

Online ultrasonic nebulizer assisted laser induced breakdown spectroscopy (OUN-LIBS): An online metal elements sensor for marine water analysis

Metal element detection technologies for seawater analysis are very important in the fields of marine scientific investigation and environmental monitoring. The current technologies cannot meet the requirements of detection capabilities, such as online, real-time, multi-element and highly sensitive while used in the above fields on-site. A newly developed sensor named online ultrasonic nebulizer assisted laser induced breakdown spectroscopy (OUN-LIBS) is introduced in this paper which is expected to be used for on-site seawater analysis. The core design idea of this sensor is to combine an online ultrasonic nebulizing auxiliary device with a traditional LIBS system to nebulize the liquid samples into aerosol for LIBS detection in order to realize a continuously, highly sensitive, stable and fast on-site detection. Based on this idea, a hardware system composed of an adapter module, a nebulizing module and an optical module and a software system with communication, control and display functions were designed. The laboratory experiments and marine field testing were carried out to assess the sensor. Under the status of continuous online detection, the LODs of the 6 target elements are lower than 1 ppm and the stability of spectral line intensity of Ca is lower than 0.38%. Besides the traditional calibration curve method, an online and on-site standard sample calibration method is adopted in the concentration quantitative analysis. The results of research show that the accuracy of online quantification analysis is very impressive even in the marine field testing.

Preparation and evaluation of natural rosin-based zinc resins for marine antifouling

Currently, it is highly desirable to develop a novel antifouling resin with a controllable hydrolysis rate and stable and effective antifouling performance for marine antifouling coatings. In our study, we prepared natural rosin-based zinc (RZn-x) resins by a relatively facile and green synthetic method from Zn(OH)2 and antimicrobial natural rosin, which is considered a toxicity-free raw material, thus ensuring the green and antimicrobial character of the material. In their optimal combination, the RZn-x coating surface exhibited ideal peeling behaviour upon immersion in seawater, which caused the WCA of the material surface to change from 55° before immersion to 135° after immersion for 60 days and enhanced the antifouling properties. Dynamic simulation experiments of these resins also demonstrated that the hydrolysis rate of this material immersed in dynamic seawater was related to the zinc content, and we could control the self-polishing ability of the resins by adjusting the content of Zn(OH)2 participating in the reaction. Moreover, hydrolysis led to a hydrophobic surface, which could prevent fouling organisms from adhering. Laboratory bioassays against BSA adsorption (immersed for 4 h: 1.986 μg/cm2), bacterial (over 95 % reduction) and marine algal adhesion (more than 60 % reduction) revealed outstanding anti-protein, bacteriostasis and anti-algal growth and adhesion properties compared to pure rosin and the control sample. The long-term antifouling capability in marine field tests indicated that the RZn-x resins maintained their antifouling activity for more than 6 months, especially RZn-50, which showed excellent antifouling performance.

Urushiol titanium polymer‐based composites coatings for anti‐corrosion and antifouling in marine spray splash zones

AbstractSeawater is highly corrosive, and the alternating dry and wet environment can cause severe corrosion in metal equipment. Moreover, marine equipment is also seriously affected by marine biofouling. These harsh conditions pose a serious threat to the integrity of marine equipment as well as their associated maritime activities and necessitate the development of effective coatings to minimize damage to the equipment. Urushiol titanium polymer/acrylic resin (UTP/AR) composite materials were developed. Then, marine anti‐corrosion and antifouling coatings were prepared from the UTP/AR composite materials using rosin‐modified Cu2O as an antifoulant. The composite coating with a UTP:AR mass ratio of 1:1 (UTP/AR3) showed the best chemical resistance and light aging resistance. UTP/AR3 also exhibited a good corrosion current density (2.009 × 10−7 A cm−2) and corrosion potential (−0.5007 V), further indicating that the UTP/AR composite coatings have excellent anti‐corrosive properties. Marine field tests showed that the UTP/AR/Cu2O composite coatings with rosin‐modified Cu2O contents less than 20% showed stable, long‐term antifouling performance after immersion in seawater for 360 day. Briefly, the UTP/AR/Cu2O composite coatings have broad application prospects in the marine industry for materials in the spray splash zone.

Implementation of the greening process at oil and gas industry enterprises

This article provides an analysis of the main problems that affect the greening of products and their marketing systems, and considers international norms, rules and environmental standards in the field of marine fuel use. The effective solution of the problem and the development of related areas of improvement of the system of introduction of greening of fuel products and its further marketing, including external, information, technological and structural components, are proposed. The development of the market for the sale of liquefied natural gas, research on the creation of fuel with a reduced sulfur content, strengthening quality control in the organizational mechanism for the sale of finished products, as well as increasing the level of greening during transshipment, transportation and bunkering are considered as directions for implementing the goal of greening.

ANALISIS KELAYAKAN INVESTASI PEMBUATAN BAGAN APUNG BARU (STUDI PADA NELAYAN BAGAN APUNG DI OESAPA, KOTA KUPANG)

ABSTRAK
 Penataan jaring angkat sebagai usaha di bidang kelautan dan perikanan, serta memproduksi ikan dengan mengikuti kondisi laut dan cuaca yang dapat berubah dan mempengaruhi kegiatan produksi sehingga memberikan pendapatan yang tidak pasti dan sulit diprediksi. Oleh karena itu, penelitian ini dilakukan dengan tujuan untuk mengetahui apakah produksi ikan dengan menggunakan jaring angkat ini dapat dikatakan layak dari aspek hukum, pasar dan pemasaran, manajemen, teknis dan operasional, ekonomi, sosial, amdal, dan keuangan. Sebelum merekomendasikan kepada investor, diperlukan analisis kelayakan investasi untuk mengetahui tingkat kelayakannya. Analisis dilakukan dengan proyeksi 10 tahun menggunakan skenario pesimis, moderat dan optimis. Beberapa hal yang perlu dilakukan adalah, legalisasi kegiatan usaha, merancang strategi pemasaran, mengetahui kegiatan teknis dan operasional, menentukan empat fungsi manajemen, mengetahui dampak positif ekonomi, sosial, dampak negatif terhadap lingkungan dan menentukan perkiraan penjualan di masa mendatang dengan menghitung untung / rugi. , arus kas, penilaian kelayakan finansial (NPV, IRR, PP dan PI) dan analisis sensitivitas. Setelah dilakukan analisa, ditemukan bahwa investasi ini layak dan dapat direkomendasikan pada setiap skenario dan tentunya skenario optimis menghasilkan tingkat kelayakan yang lebih baik dibandingkan dengan skenario lainnya.
 Kata Kunci: Analisis Kelayakan, Investasi, Lift Net, Industri Perikanan.

Mechanical and Corrosion Studies of Friction Stir Welded Nano Al2O3 Reinforced Al-Mg Matrix Composites: RSM-ANN Modelling Approach

Nano aluminum oxide was prepared by the combustion method using aluminum nitrate as the oxidizer and urea as a fuel. Characterization of synthesized materials was performed using SEM (scanning electron microscope), powder XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), and TEM (transmission electron microscope). Al-Mg/Al2O3 (2, 4, 6, and 8 wt%) metal matrix nanocomposites were prepared by liquid metallurgy route-vertex technique. The homogeneous dispersion of nano Al2O3 particles in Al-Mg/Al2O3 metal matrix nanocomposites (MMNCs) was revealed from the field emission SEM analysis. The reinforcement particles present in the matrix were analyzed through energy-dispersive X-ray spectroscopy method. The properties (corrosion and mechanical) of the fabricated composites were evaluated. The mechanical and corrosion properties of the prepared nanocomposites initially increased and then decreased with the addition of nano Al2O3 particles in Al-Mg Matrix. The studies show that, the presence of 6 wt% of nano Al2O3 particles in the matrix improved the properties of other combinations of nano Al2O3 in the Al-Mg matrix material. Further, the Al-Mg/Al2O3 (6 wt%) MMNCs are joined by friction stir welding and evaluated for microstructural, mechanical, and corrosion properties. Al-Mg/Al2O3 MMNCs may find applications in the marine field. The response surface method (RSM) was used for the optimization of tensile strength, Young’s modulus, and microhardness of the synthesized material which resulted in a 95% of statistical confidence level. Artificial neural network (ANN) analysis was also carried out which perfectly predicted these two properties. The ANN model is optimized to obtain 99.9% accurate predictions by changing the number of neurons in the hidden layer.

The Essentials of Marine Biotechnology

Coastal countries have traditionally relied on the existing marine resources (e.g., fishing, food, transport, recreation, and tourism) as well as tried to support new economic endeavors (ocean energy, desalination for water supply, and seabed mining). Modern societies and lifestyle resulted in an increased demand for dietary diversity, better health and well-being, new biomedicines, natural cosmeceuticals, environmental conservation, and sustainable energy sources. These societal needs stimulated the interest of researchers on the diverse and underexplored marine environments as promising and sustainable sources of biomolecules and biomass, and they are addressed by the emerging field of marine (blue) biotechnology. Blue biotechnology provides opportunities for a wide range of initiatives of commercial interest for the pharmaceutical, biomedical, cosmetic, nutraceutical, food, feed, agricultural, and related industries. This article synthesizes the essence, opportunities, responsibilities, and challenges encountered in marine biotechnology and outlines the attainment and valorization of directly derived or bio-inspired products from marine organisms. First, the concept of bioeconomy is introduced. Then, the diversity of marine bioresources including an overview of the most prominent marine organisms and their potential for biotechnological uses are described. This is followed by introducing methodologies for exploration of these resources and the main use case scenarios in energy, food and feed, agronomy, bioremediation and climate change, cosmeceuticals, bio-inspired materials, healthcare, and well-being sectors. The key aspects in the fields of legislation and funding are provided, with the emphasis on the importance of communication and stakeholder engagement at all levels of biotechnology development. Finally, vital overarching concepts, such as the quadruple helix and Responsible Research and Innovation principle are highlighted as important to follow within the marine biotechnology field. The authors of this review are collaborating under the European Commission-funded Cooperation in Science and Technology (COST) Action Ocean4Biotech – European transdisciplinary networking platform for marine biotechnology and focus the study on the European state of affairs.

Simulations and Tests of Composite Marine Structures Under Low-Velocity Impact

Abstract Due to their excellent performance, composite materials are increasingly used in the marine field. It is of great importance to study the low-velocity impact performance of composite laminates to ensure the operational safety of composite ship structures. Herein, low-velocity drop-weight impact tests were carried out on 12 types of GRP laminates with different layup forms. The impact-induced mechanical response characteristics of the GRP laminates were obtained. Based on the damage model and stiffness degradation criterion of the composite laminates, a low-velocity impact simulation model was proposed by writing a VUMAT subroutine and using the 3D Hashin failure criterion and the cohesive zone model. The fibre failure, matrix failure and interlaminar failure of the composite structures could be determined by this model. The predicted mechanical behaviours of the composite laminates with different layup forms were verified through comparisons with the impact test results, which revealed that the simulation model can well characterise the low-velocity impact process of the composite laminates. According to the damage morphologies of the impact and back sides, the influence of the different layup forms on the low-velocity impact damage of the GRP laminates was summarised. The layup form had great effects on the damage of the composite laminates. Especially, the outer 2‒3 layers play a major role in the damage of the impact and the back side. For the same impact energy, the damage areas are larger for the back side than for the impact side, and there is a corresponding layup form to minimise the damage area. Through analyses of the time response relationships of impact force, impactor displacement, rebound velocity and absorbed energy, a better layup form of GRP laminates was obtained. Among the 12 plates, the maximum impact force, absorbed energy and damage area of the plate P4 are the smallest, and it has better impact resistance than the others, and can be more in line with the requirements of composite ships. It is beneficial to study the low-velocity impact performance of composite ship structures.

Phase-Amplitude Least-Squares Reverse Time Migration With a Simultaneous-Source Based on Sparsity Promotion in the Time-Frequency Domain

Least-squares reverse time migration (LSRTM) aims to produce a high-quality migration image of complex geological structures. However, the weaker deep seismic reflections are often masked by the overlying strata in migration images. Therefore, it is difficult for the LSRTM to image the deeper structures. This letter proposes a phase-amplitude LSRTM (PA-LSRTM) in the time-frequency domain to improve the migration image of deep seismic reflections and subsalt structures. The PA-LSRTM is formulated as an inverse problem that minimizes the time-frequency phase-amplitude difference between the predicted and observed data. The seismic data was initially transformed into the time-frequency domain to establish a PA-LSRTM misfit. An amplitude factor was then introduced in the time-frequency misfit to weaken the weights of amplitude components. In this case, it emphasized the similarity of phase components. Furthermore, the sparsity promotion method was combined with a simultaneous source technique to increase the computational efficiency and reduce the crosstalk noise. The PA-LSRTM with sparsity promotion (SPA-LSRTM) misfit can finally be solved using a Fast Iterative Shrinkage-Thresholding Algorithm (FISTA). The numerical and marine field data tests demonstrate that the SPA-LSRTM can effectively produce a high-resolution image of deep structures.

Synthesis and Biological Activity of Acrylate Copolymers Containing 3-Oxo-N-allyl-1,2-benzisothiazole-3(2H)-carboxamide Monomer as a Marine Antifouling Coating.

A type of grafted acrylate copolymer resins, containing 3‐oxo‐N‐allyl‐1,2‐benzisothiazole‐2(3H)‐carboxamide monomer and heterocyclic monomers, was synthesized through the copolymeri‐ zation of methyl methacrylate (MMA) and butyl acrylate (BA) with functional monomers. The structures of the monomers and copolymers were validated by infrared (IR) and 1H nuclear magnetic resonance (NMR) spectroscopies. The inhibitory activities of the copolymers on algae, bacteria, and barnacle larvae were measured, and the antifouling potencies against marine macrofouling organisms were investigated. The results showed that the grafted resin had significant inhibitory effects on the growth of three marine algae (Isochrysis galbana, Nannochloropsisoculata, and Chlorella pyrenoidosa), and three bacteria (Vibrio coralliilyticus, Staphylococcus aureus,and Vibrio parahaemolyticus). The target copolymers also showed excellent inhibition of the survival of barnacle larvae. Additionally, the release rate of the antifoulant and the results of the marine field tests indicated that the grafted copolymers had outstanding antifouling potency against the attachment of marine macrofouling organisms.

Evolution of Fatigue Crack Growth Phenomena in Friction Stir Welded AA2xxx Alloys

Aluminum 2xxx alloys have been one of the primary materials for the structural applications of aerospace and transportation industry because of their performance, manufacturing and reliable inspection techniques. Welding is very important in the manufacturing process of structural parts and is now known as the most vital process in the manufacturing route. A relatively new process of joining of materials is friction stir welding process, which was invented by The Welding Institute (TWI) in the UK in 1991. The friction stir welding is mainly employed in aerospace, marine and transportation fields that have high safety requirements. The failure by fatigue is the dominant failure mode for structural weld joints. Since fatigue failure of parts accounts for 50 to 90% of all failures, it is of great significance to understand the fatigue properties of friction stir welded joints. The aim of this overview is to summarize the current research on fatigue crack growth behavior of friction stir welded AA2xxx alloys and critical attention is payed to the damage tolerance performance of friction stir welded aluminum joints that can be affected by welding process parameters, residual stress, stress ratio, environment and post weld treatments.

The Impact of IUU Fishing Policy (Moratorium License of Fishery Commerce) to the level of Employment of Maritime and Fishery Vocational Schools Graduates

The limited capacity of human resources (HR) that is competent in their field often causes the less than optimal utilization of the marine and fisheries resources in Indonesia. Maritime and Fishery Vocational Schools (MFVS) can be the solution to this problem, as they are expected to generate capable and competitive human resources; thus, utilizing and sustainably managing the vast marine resources in Indonesia, and in turn improving the efforts taken to advance Indonesian people’s welfare. However, the level of employment for MFVS graduates in Indonesia is still limited to large scale fishing activities. Additionally, since the launch of Moratorium License of Fishery Commerce of Fishery States in the Republic of Indonesia (56/PERMEN-KP/2014) by the Indonesian Ministry of Marine and Fisheries (IMMaF), most fishery companies have ceased to operate. The study aimed to determine the impact caused by this regulation against the level of employment of MFVS graduates, as well as the scheme of policies that should be applied to maximize the human resources in the field of marine and fisheries. This research used a qualitative method, where the descriptive analysis was used as a primary tool of analysis. The results of the analysis indicated that the trend of employment of MFVS graduates shifted after the enactment of this policy. The lack of synergy between policies in the field of marine and fisheries and policies in the field of education and transportation resulted in the difficulty of MFVS graduates to achieve a good career in this field..

Traditional and non-traditional machining of nickel-based superalloys: A brief review

As nickel-based superalloys have heat and oxidation resisting capability, there are numerous applications of it in the field of marine and aerospace. This paper focuses on the review of traditional and non-traditional machining processes implemented for nickel-based superalloys over the past decade. The challenges faced during the implementation of conventional machining processes and the application areas in which nickel-based superalloys used have also been discussed. Most commonly used nickel-based alloys for a variety of applications and studies are presented. The consolidated information about the implementation of these machining processes for nickel-based superalloys is listed, and the paper concludes with some key findings and gaps about the machining of nickel-based superalloys.

Mechanical behavior of sandwich structures with varying core material – A review

This investigation is to review the effect of mechanical behavior of sandwich structures made of two metal plates (like aluminum, copper, steel etc.,) as base and a core material, the properties are analyzed by varying the loads on the base metal, core material and as well as on the sandwich structure to compare the individual strength and mechanical characteristics with different alloys and composite materials of same weight. This analysis may help to precede us to take the next step in demonstrating the applications of sandwich structure made of above-mentioned materials in various engineering fields like body parts of automobiles, marine field, light weight structures, windmill blades etc. Also, the results obtained from this review are also compared with properties/characteristics of sandwich structures with different core material (like pvc, plastic, polymers, graphene, honeycombs, folded core etc.)

Soft Thresholding Attention Network for Adaptive Feature Denoising in SAR Ship Detection

Recently, synthetic aperture radar (SAR) ship detection is used in many applications within the marine field, such as fishery management, traffic control, and urgent rescue operations. Meanwhile, deep learning-based methods have bought new capabilities for ship detection in SAR images on account of high accuracy and robustness. However, several challenges remain to be addressed: 1) the shapes of the ships in SAR images have a relatively extreme aspect ratio comparing to the target objects in the optical images, and 2) complex background and clutter noise result in adverse effects for the network to extract prototypical SAR target features, which limit the ship detection performance. To address these issues, this paper proposes two effective approaches to augment the feature extraction ability of the network. Firstly, IOU (Intersection over Union) K-means is carried out to settle the extreme aspect ratio problem. The IOU K-means, as a preprocessing step, clusters a set of aspect ratios from datasets that are suitable for ship detection. Secondly, we embed a soft thresholding attention module (STA) in the network to suppress the impact of noise and complex background. The comparison results with several state-of-the-art object detection algorithms confirm the efficiency and feasibility of proposed approaches.

Recent researches on Cu-Ni alloy matrix composites through electrodeposition and powder metallurgy methods: A review

Copper-nickel (Cu-Ni) alloy matrix composites have been extensively used in many industries due to their high mechanical strength, good wear and corrosion resistance, and exceptional electrocatalytic properties. This review gives a comprehensive overview of the recent development in the synthesis of Cu-Ni alloy matrix composites by electrodeposition and powder metallurgy methods. The incorporation of particles into the Cu-Ni alloy matrix produced improved properties in the fields of mechanical, chemical, marine and electronics engineering. In the marine environment, an increase in demand for high corrosion and wear resistance properties for boat hulls, marine hardware, condensers and heat exchangers were observed. Cu-Ni alloy matrix composites prepared using the electrodeposition method suggest a most simple and economical way to improve the overall properties.

Synergistic effect of copolymeric resin grafted 1,2-benzisothiazol-3(2H)-one and heterocyclic groups as a marine antifouling coating.

In order to find a new type of antifouling coating with higher biological activity and more environmental protection, heterocyclic compounds and benzisothiazolinone were introduced into acrylic resin to prepare a new type of antifouling resin. In this study, a series of grafted acrylic resins simultaneously containing benzoisothiazolinone and heterocyclic monomers were prepared by the copolymerization of an allyl monomer with methyl methacrylate (MMA) and butyl acrylate (BA). Inhibitory activities of the copolymers against marine fouling organisms were also investigated. Results revealed that the copolymers exhibit a clear synergistic inhibitory effect on the growth of three seaweeds: Chlorella, Isochrysis galbana and Chaetoceros curvisetus, respectively, and three bacteria, Staphylococcus aureus, Vibrio coralliilyticus and Vibrio parahaemolyticus, respectively. In addition, the copolymers exhibited excellent inhibition against barnacle larvae. Marine field tests indicated that the resins exhibit outstanding antifouling potency against marine fouling organisms. Moreover, the introduction of the heterocyclic group led to the significantly enhanced antifouling activities of the resins; the addition of the heterocyclic unit in copolymers led to better inhibition than that observed in the case of the resin copolymerized with only the benzoisothiazolinone active monomer.

Seismic data interpolation using deep learning with generative adversarial networks

ABSTRACTWe propose an algorithm for seismic trace interpolation using generative adversarial networks, a type of deep neural network. The method extracts feature vectors from the training data using self‐learning and does not require any pre‐processing to create the training labels. The algorithm also does not make any prior explicit assumptions about linearity of seismic events or sparsity of the data, which are often required in the traditional interpolation methods. We create the training labels by removing traces from different receiver indices of the original datasets to simulate the effect of missing traces. We adopt the framework of the generative adversarial networks to train the network and add additional loss functions to regularize the model. Numerical examples using land and marine field datasets demonstrate the validity and effectiveness of the proposed approach. With minimal computational burden and proper training, the proposed method can be applied to three‐dimensional seismic datasets to achieve accurate interpolation results.

Annual phytoplankton succession results from niche-environment interaction

AbstractAnnual plankton succession has been investigated for many decades with hypotheses ranging from abiotic to biotic mechanisms being proposed to explain these recurrent patterns. Here, using data collected by the Continuous Plankton Recorder (CPR) survey and models originating from the MacroEcological Theory on the Arrangement of Life, we investigate Annual Phytoplankton Succession (APS) in the North Sea at a species level. Our results show that this phenomenon can be predicted well by models combining photosynthetically active radiation, temperature and macro-nutrients. Our findings suggest that APS originates from the interaction between species’ ecological niches and the annual environmental fluctuations at a community level. We discuss our results in the context of traditional hypotheses formulated to explain this recurrent pattern in the marine field.

Absolute Salinity Measurement Based on Microfiber Coaxial Mach-Zehnder Interferometer

Li, Y.; Wang, J., and Wang, S., 2020. Absolute salinity measurement based on microfiber coaxial Mach-Zehnder interferometer. In: Jung, H.-S.; Lee, S.; Ryu, J.-H., and Cui, T. (eds.), Advances in Geospatial Research of Coastal Environments. Journal of Coastal Research, Special Issue No. 102, pp. 194-201. Coconut Creek (Florida), ISSN 0749-0208.Seawater salinity is a key parameter in the study of ocean dynamics, accurate measurement of seawater salinity is crucial. However, current seawater salinity is a measure of practical salinity, which limits the accuracy of salinity measurements. The proposed absolute salinity compensates for the flaws in the practical salinity that does not accurately reflect the true salinity of seawater. Microfiber sensors enable highly sensitive measurements of absolute salinity in seawater. In this paper, a new method based on microfiber coaxial Mach-Zehnder interferometer (coaxial MZI) is proposed for seawater absolute salinity measurement. The absolute salinity sensitivity of microfiber coaxial MZI is calculated by finite element program, and the theoretical results show that the sensitivity increases with increasing wavelength and increases with the decrease of waist diameter. Thirteen microfiber coaxial MZIs with different diameter were fabricated and used for the measurement of absolute salinity. Experimental results show that the highest sensitivity is 2.38nm/ ‰, and the variations rules of sensor sensitivity are consistent with theoretical calculations. In addition, in order to promote the practical application of microfiber devices in the marine field, coaxial MZI is encapsulated. The salinity response time, time stability and vibration influence of the sensor were tested by experiments. Encapsulated coaxial MZI is expected to realize the in-site measurement of the absolute salinity of seawater.