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Results in Journal Sustainable Marine Structures: 36

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Selda Oterkus, Bingquan Wang, Erkan Oterkus, Yakubu Kasimu Galadima, Margot Cocard, Stefanos Stefanos, Jami Buckley, Callum McCullough, Dhruv Boruah, Bob Gilchrist
Sustainable Marine Structures, Volume 4, pp 11-17; https://doi.org/10.36956/sms.v4i2.505

Abstract:
Unlike traditional transportation, container transportation is a relatively new logistics transportation mode. Shipping containers lost at sea have raised safety concerns. In this study, finite element analysis of containers subjected to hydrostatic pressure, using commercial software ANSYS APDL was performed. A computer model that can reasonably predict the state of an ISO cargo shipping container was developed. The von Mises stress distribution of the container was determined and the yield strengthwas adopted as the failure criterion. Numerical investigations showed that the conventional ship container cannot withstand hydrostatic pressure in deep water conditions. A strengthened container option was considered for the container to retain its structural integrity in water conditions.
Erkan Oterkus, Sangchan Jo
Sustainable Marine Structures, Volume 4, pp 16-28; https://doi.org/10.36956/sms.v4i1.476

Abstract:
In offshore structures, hydrocarbon fires cause the structure to loose its rigidity rapidly and this leads to structural integrity and stability problems. The Passive Fire Protection (PFP) system slows the transfer rate of fire heat and helps to prevent the collapse of structures and human losses. The vital design factors are decided in the detailed design stage. The determined design thickness must be accurately applied in the fabrication yard. However, there are many cases that the PFP is overused because of various reasons. This excessive application of the PFP is an unavoidable problem. Several studies have been conducted on the efficient application and optimal design of the PFP. However, the strength of the PFP has not been considered. In addition, research studies on the correlation between the thickness of the PFP and the structural behaviour are not widely available. Therefore, this study attempts to analyse the thermal and mechanical effects of the PFP on the structure when it is applied to the structural member. In particular, it is intended to determine the change in the behaviour of the structural member as the thickness of the PFP increases.
Chungkuk Jin
Sustainable Marine Structures, Volume 4; https://doi.org/10.36956/sms.v4i2.492

Abstract:
This study investigates the hydro-elastic behaviors of fully submerged horizontal cylinders in different regular waves. Two methods were proposed and compared in this study. The first method was based on potential theory in frequency domain and the discrete-module-beam (DMB) method, which discretizes a floating elastic structure into a sufficient number of rigid bodies while simultaneously representing the elastic behavior from beam elements with Euler-Bernoulli beam and Saint-Venant torsion. Moreover, the Morison method in time domain was employed; this method estimates wave forces from the semi-empirical Morison equation, and the elastic behavior is embodied by massless axial, bending, and torsional springs.Various parametric studies on cylinder diameter, submergence depth, and wave direction were conducted. Wave forces, dry/wet mode shapes/natural frequencies, and dynamic motions are presented and analyzed.
Erkan Oterkus
Sustainable Marine Structures, Volume 4, pp 13-15; https://doi.org/10.36956/sms.v4i1.475

Abstract:
Marine environment is a harsh and challenging environment for both operators and analysers due to extreme weather conditions. As a result of these conditions, marine structures are subjected to extreme and/or cyclic loadings. This will then lead to various different damage modes including corrosion and fatigue. Such damage modes are major threats to the reliability and integrity of marine structures which can cause risk on human and environmental safety, and yield financial losses. Moreover, climate change is a major concern which requires urgent attention. In order to minimize the negative effects of climate change, energy transition from utilisation of fossil fuels to greener energy solutions, such as offshore wind, should be adapted. There is currently a rapid progress on investment on green technologies especially offshore wind energy generation. Another emerging area is hydrogen which is considered as the environmentally friendly fuel of the future.
Srinivasan Chandrasekaran, Hari S
Sustainable Marine Structures, Volume 4, pp 35-41; https://doi.org/10.36956/sms.v4i1.490

Abstract:
Marine structures are exposed to harsh weather conditions, demanding special pre-requisites in design and functional perspectives. Under dynamic loads of larger magnitude, the material-centric design procedure alone is not feasible to ensure the safe disbursement of loads. The compliant offshore structures resist loads primarily by their geometric novelty, and hence their design is form-dominant and no more strength (material) dominant. Large displacements in the rigid body modes in the horizontal plane under lateral loads require their construction material to possess enough ductility to absorb this energy. Steel is one of the most competitive materials for marine structures as it offers good ductility, but corrosion in the marine environment is a major concern. It undergoes strength and functional degradations and therefore requires serious investigation. In the present study, functionally graded material (FGM) is proposed to substitute for steel in marine applications. The method of fabricating FGM and assessing its mechanical and durability properties are discussed. Results show that FGM possesses strength and durability properties at par with the conventionally used X52 steel for marine risers. The presented study will be a major initiative towards future research in exploring competent materials which will be strong and sustainable in the marine environment.
Liang-Cheng Liu, Ge Wang, Jun-Yi Song, Bi-Ru Hu
Sustainable Marine Structures, Volume 4, pp 29-34; https://doi.org/10.36956/sms.v4i1.438

Abstract:
Resolving the contradiction between Marine economic development and Marine ecological environment protection has become an unavoidable and sharp problem. The uncontrolled use of Marine antifouling technology will bring uncontrollable and even irreversible damage to the Marine biosphere, which will lead to ecological disaster and threaten the survival of human beings. Therefore, it is an urgent task to find antifouling technology with lower environmental toxicity under the premise of considering economy. More attention should be paid to the long-term impact of mature and new technologies on the Marine ecological environment. This paper introduces the development status of antifouling technology, its influence on Marine ecological environment and puts forward the design strategy of comprehensive biological fouling prevention and control technology.
Zhang ChunLing, Zhang Meng-Li, Wang Zhen-Feng, Hu Song, Wang Dan-Yang, Yang Sheng-Long
Sustainable Marine Structures, Volume 4, pp 1-12; https://doi.org/10.36956/sms.v4i1.474

Abstract:
Argo has become an important constituent of the global ocean observation system. However, due to the lack of sea surface measurements from most Argo profiles, the application of Argo data is still limited. In this study, a thermocline model was constructed based on three key thermocline parameters, i.e, thermocline upper depth, the thermocline bottom depth, and thermocline temperature gradient. Following the model, we estimated the sea surface temperature of Argo profiles by providing the relationship between sea surface and subsurface temperature. We tested the effectiveness of our proposed model using statistical analysis and by comparing the sea surface temperature with the results obtained from traditional methods and in situ observations in the Pacific Ocean. The root mean square errors of results obtained from thermocline model were found to be significantly reduced compared to the extrapolation results and satellite retrieved temperature results. The correlation coefficient between the estimation result and in situ observation was 0.967. Argo surface temperature, estimated by the thermocline model, has been theoretically proved to be reliable. Thus, our model generates theoretically feasible data present the mesoscale phenomenon in more detail. Overall, this study compensates for the lack surface observation of Argo, and provides a new tool to establish complete Argo data sets.
O.A. Adeboyejo, E.O. Clarke, A.M. Hammed, O.O. Whenu, J.P. Abayomi, O.M. Olarewaju
Sustainable Marine Structures, Volume 3; https://doi.org/10.36956/sms.v3i2.434

Abstract:
A study on seasonal abundance, morphometric and meristic data, growth pattern, condition factor, sex ratio and gonadosomatic index of Liza falcipinnis (Valenciennes, 1836) from the Ojo axis of Badagry creek, Nigeria was conducted from May 2019 to March 2020. A total of 1012 species were randomly selected, having 499 females and 513 males. The length frequency analysis and length-weight relationships (LWR) were determined. Sex ratio was determined by Chi-square analysis. The results showed that morphometric data are: 0.5 - 2.5 mm for ED, 2.1 - 12 mm for HL, 1.7 - 8.1 mm for HD, 2.5 - 11.7 for BD, 2.6 - 233.3 mm for TL and 9.23 - 1006 g for BW for the combined sexes. The slope (b) shows an allometric growth pattern. The intercept ‘a’ and slope ‘b’ of the LWR (LogW = a + bLogL) were Log W=15.39+ 0.34 LogL (r= 0.54) for combined sexes, Log W= 12.49+ 0.02 log L (r= 0.38) for males and Log W= 18.23+ 0.01 log L (r=0.16) for females.The length frequency distribution indicated that species were dominated by two year classes (Ages 1 and 2). Condition factors were generally low. The values ranged between 0.68 - 0.85 for combined sexes. The gonadosomatic index for female was highest in August, 2019 (17.77%) with Mean±SD of 2.88±0.75; which indicated the peak of spawning period in the study area.Sex ratio difference was significant (P<0.05). Sexual differences were significant; the females are phenotypically larger than the male.
B. K. Chakraborty, Verma A. K., S. Muniya
Sustainable Marine Structures, Volume 3; https://doi.org/10.36956/sms.v3i2.436

Abstract:
Bangladesh is very rich in aquatic fauna with a biodiversity. The present study, conducted during 2015 to 2019, recorded a total number of 131 spe cies (104 fish, 09 prawn, 01 snail, 04 crabs, and 13 turtles) belonging to 26 families were identified from the Mogra River and its flood plain. About ten types of fishing gears, different crafts, hook and line were found oper ative in the river. Increasing rates of using current jal (16.0-26.40%) and Kapuri jal (11.0-16.70%) were identified as detrimental gears destroyingdifferent species. The fish productivity was decreased dramatically from 170.63±10.81mt to 134.75±8.02 mt with a decreasing percentage of 6.26 to 21.03% within five years. Three important aquatic species turtiles (Cyclemys oldhami, Melanocheelys trjuuga and Morenia petersi) became rare and 17 commercially important aquatic species were at the edge of extinction (critically endangered, CR). From the study, 67 species were recorded inthe endangered (EN) category, 20 species vulnerable status (VU), 11 species lower risk (LR), 07 species Least concern (LC) and 04 Data deficient (DF). To save the existing aquatic species in the studied riverine ecosystem and ensure better livelihood of the fishes, a team of local management committee, similar to the Hilsa fisheries management technology is needed.
Abdelaziz Mounir, Mohammed Znari, Hayat Elmghazl, Hassan Alahyane, Noreddine Chouikh, Nawal Hichami
Sustainable Marine Structures, Volume 3; https://doi.org/10.36956/sms.v3i2.433

Abstract:
This article summarizes the state of stocks of sardine, sardina pilchardus in Moroccan waters at the end of 2016 and 2018. These stocks varies according to the region,They are now in a sustainable exploitation situation:Atlantic sardine, but also stocks that have reached or are still in over-exploitation levels: Mediterranean sardine. The fi shing pressure exerted on the sardine stock exceeds the optimal level by 40%. Due to the degradation of the fragile marine environment of the Mediterranean region, generated by pollution of various origins, the overexploitation of juveniles in the coastal strip, non-responsible practices and the use of non-fi shing gearselective, it is imperative to take the necessary measures to protect the marine environment and ensure rational and sustainable exploitation of the resource. (High commission plan 2006 report).
Luis Felipe Avilés-Ramírez, Joanna M. Ortiz-Alcantara, Ma. Leticia Arena-Ortiz
Sustainable Marine Structures, Volume 3; https://doi.org/10.36956/sms.v3i2.432

Abstract:
Plastic pollution has become an urgent issue, since its invasion to every ecosystem has led to multiple impacts on the environment and human populations. Certain microbial strains and genera had shown the ability to biodegrade plastic sources under laboratory conditions. In this minireview, we collect and analyze scientific papers and reports of this microbial activity as we contextualize this information on the global plastic pollution problem, to provide an updated state of the art of plastic biodegradation with microbial agents. Along with a broad understanding of the general process of plastic biodegradation hosted by microorganisms. The contributions of this minireview come from the identification of research gaps, as well as proposals for new approaches. One of the main proposals focuses on coastal environments and in particular coastal wetlands as a great microbiome source with potential for plastic biodegradation, whether reported or undiscovered. Our final proposal consists of the application of this knowledge into technologic tools and strategies that have a remarkable impact on the battle against the plastic pollution problem.
Liana De Figueiredo Mendes, Patrícia Pinheiro Beck Eichler, Tatiana Leite, Ana Beatriz Alves Bennemann, Clara De Souza Melo, Andressa Lima Ferreira, Khalil Bow Ltaif Garcia, Luzia Liniane Do Nascimento Silva, Christofer Paul Barker, Helenice Vital, et al.
Sustainable Marine Structures, Volume 3; https://doi.org/10.36956/sms.v3i2.431

Abstract:
In 2019, an oil spill in Brazil, of unknown origin, severely impacted coastal environs with the worst environmental disaster ever recorded in any tropical coastal region globally severely damaging South Pirangi Reef area in the state of Rio Grande do Norte (RN). Here we discuss acute and chronic impacts including chemical contamination and economic consequences all over the world and show some evidence of the oil spill in this biodiverse area. Moreover, the lapse between the moment of the disaster, and the action to manage it, was hampered by a political agenda coinciding with local and global tragedies that redirected public attention. Meanwhile almost 2 years have passed still without the offending party identification or culpability; and poor communities may continue to absorb its deleterious impacts for decades without consideration or compensation. This disaster occurred during the Brazilian government’s current issues involving extensive environmental mismanagement, resulting in a slow response from an inept system. It is with urgent necessity to spotlight this tragedy in this unique and sensitive reef habitat experiencing the ongoing damaging effects that include socio-economic losses not yet addressed.
Ahmed O. Elaghbash
Sustainable Marine Structures, Volume 3; https://doi.org/10.36956/sms.v3i1.414

Abstract:
The demand for high-speed boats that operating near to shoreline is increasing nowadays. Understanding the behavior and attitude of high speed boats when moving in different waterways is very important for boat designer. This research uses a CFD (Computational Fluid Dynamics) analysisto investigate the shallow water effects on prismatic planing hull. The turbulence fl ow around the hull was described by Reynolds Navier Stokes equations RANSE using the k-ɛ turbulence model. The free surface was modelled by the volume of fl uid (VOF) method. The analysis is steady for all the ranges of speeds except those close to the critical speed range Fh=0.84 to 1.27 due to the propagation of the planing hull solitary waves at this range. In this study, the planing hull lift force, total resistance, and wave pattern for the range of subcritical speeds, critical speeds, and supercritical speeds have been calculated using CFD. The numerical results have been compared with experimental results. The dynamic pressure distribution on the planing hull and its wave pattern at critical speed in shallow water were compared with those in deep water. The numerical results give a good agreement with the experimental results whereas total average error equals 7% for numerical lift force, and 8% for numerical total resistance. The worst effect on the planing hull in shallow channels occurs at the critical speed range, where solitary wave formulates.
Saleem Mustafa, Sitti Raehanah M. Shaleh, Rossita Shapawi, Abentin Estim, Ching Fui Fui, Ag. Asri Ag. Ibrahim, Audrey Daning Tuzan, Lim Leong Seng, Chen Cheng Ann, Alter Jimat, et al.
Sustainable Marine Structures, Volume 3; https://doi.org/10.36956/sms.v3i1.378

Abstract:
This study was undertaken to examine the options and feasibility of deploying new technologies for transforming the aquaculture sector with the objective of increasing the production efficiency. Selection of technologies to obtain the expected outcome should, obviously, be consistent with the criteria of sustainable development. There is a range of technologies being suggested for driving change in aquaculture to enhance its contribution to food security. It is necessary to highlight the complexity of issues for systems approach that can shape the course of development of aquaculture so that it can live-up to the expected fish demand by 2030 in addition to the current quantity of 82.1 million tons. Some of the Fourth Industrial Revolution (IR4.0) technologies suggested to achieve this target envisage the use of real-time monitoring, integration of a constant stream of data from connected production systems and intelligent automation in controls. This requires application of mobile devices, internet of things (IoT), smart sensors, artificial intelligence (AI), big data analytics, robotics as well as augmented virtual and mixed reality. AI is receiving more attention due to many reasons. Its use in aquaculture can happen in many ways, for example, in detecting and mitigating stress on the captive fish which is considered critical for the success of aquaculture. While the technology intensification in aquaculture holds a great potential but there are constraints in deploying IR4.0 tools in aquaculture. Possible solutions and practical options, especially with respect to future food choices are highlighted in this paper.
Sathit P., Chatchapol C., Phansak I.
Sustainable Marine Structures, Volume 3; https://doi.org/10.36956/sms.v3i1.316

Abstract:
A gyro-stabilizer is the interesting system that it can apply to marine vessels for diminishes roll motion. Today it has potentially light weight with no hydrodynamics drag and effective at zero forward speed. The twin-gyroscope was chosen. Almost, the modelling for designing the system use linear model that it might not comprehensive mission requirement such as high sea condition. The non-linearity analysis was proved by comparison the results between linear and non-linear model of gyro-stabilizer throughout frequency domain also same wave input, constrains and limitations. Moreover, they were cross checked by simulating in time domain. The comparison of interested of linear and non-linear close loop model in frequency domain has demonstrated the similar characteristics but gave different values at same frequency obviously. The results were confirmed again by simulation in irregular beam sea on time domain and they demonstrate the difference of behavior of both systems while the gyro-stabilizers are switching on and off. From the resulting analysis, the non-linear gyro-stabilizer model gives more real results that correspond to more accuracy in a designing gyro-stabilizer control system for various amplitudes and frequencies operating condition especially high sea condition.
Ida Bagus Mandhara Brasika, Putra Bagus Panji Pamungkas
Sustainable Marine Structures, Volume 3; https://doi.org/10.36956/sms.v3i1.354

Abstract:
Water is a basic need. However there are many near coastal regions which have very limited access to fresh water. The water in area close to coastal is mainly affected by ocean, indirectly by weather/climate conditions and directly from seawater intrusion. While abundant fresh water is actually available in the atmosphere in the form of moisture. Recent technology, such as Atmospheric Water Generator (AWG), is a possible solution to gain water from our atmosphere. However, comprehensive study is needed to understand the potential water harvesting in our atmosphere. Here, we examine the water availability in the atmosphere based on several parameters like temperature and humidity. The data are collected from observation using WS1040 Automatic Weather Station in a year of 2020 with a half-hour interval. Then, we calculate the availability of water content during each season, especially in dry conditions. We also simulate the water harvesting to fulfil daily basic need of fresh water. The atmospheric parameters have shown a monsoonal pattern. Water content decrease in atmosphere during the dry season but the water deficit occurs after the dry season. Although water harvesting able to supply daily freshwater need, it is not recommended to be a single source as it requires massive water storage and high-efficient AWG.
Do Duc Luu, Cao Duc Hanh, Nguyen Xuan Tru
Sustainable Marine Structures, Volume 2, pp 35-38; https://doi.org/10.36956/sms.v2i2.330

Abstract:
Vector of diagnostic signs (VDS) using torsional vibration (TV) signal on the main propulsion plant (MPP) is the vector of z maxima (or minima) values of the TV signal in accordance with the cylinder firing orders. The technical states of the main diesel engine (MDE) include R= z+1 classes and are presented in z-dimensional space coordinate of VDS. The presentation of Dk, k=1÷R using z diagnostic signs (Vi, i=1÷z) is nonfigurative and quite complicated. This paper aims to develop a new method for converting VDS from z-dimensional to 2-dimensional space (two-axes) based on working angle of a cylinder. The new vector of diagnostic signs VN is constructed as the geometrical grand total of all VDS:, where; ; and. The proposed model is useful for presenting a technical state Dk in two-dimensional space (x, y) in a visualization way. The algorithm and simulation software are designed for the DME 6S46-MCC, installed on the motor vessel (MV) 34000DWT. The R technical state classes are drawn separately and visually in the Descartes. The received results are valuable to improve smart diagnostic system for analyzing normal/misfire states of cylinders in operation regimes
N.K Owhonda
Sustainable Marine Structures, Volume 2; https://doi.org/10.36956/sms.v2i2.301

Abstract:
The edible flesh of guinean tilapia (Tilapia guineensis), blackchin tilapia (Sarotherondon melanotheron) and mullet (Liza falcipinnis) were collected from Choba river for elemental studies of cadmium, mercury, arsenic, lead, nickel and speciated forms of elements using X-ray fluorescence (XRF) and Gas chromatography-mass spectrometer (GC-MS) respectively. The highest concentration of cadmium (4.3mg/kg) was observed in Sarotherodon melanotheron. They all contained about the same concentration of arsenic (0.5mg/kg) and mercury (1mg/kg). The highest concentration of lead was detected in mullet (1.7mg/kg) while the highest concentration of nickel (7.3mg/kg) was detected in Sarotherodon melanotheron. The organometallic compounds detected were nickel tetracarbonyl, borane carbonyl in Tilapia guineensis, nickel tetracarbonyl, borane carbonyl and germanium(iv) pthalocyanine dichloride in Sarotherodon melanotheron and [µ-(ƞ6-benzene)]bis(ƞ5-2,4-cyclopentadien-yl)di-µ-hydrodi-vanadium and borane carbonyl in mullet
Khin Khin Gyi, Wint Thuzar Nwe, Zin Zin Zaw, Khin Khin San
Sustainable Marine Structures, Volume 2; https://doi.org/10.36956/sms.v2i2.308

Abstract:
Regarding the spatial and seasonal variations of dinoflagellates in different salinities regimes, Prorocentrum rostratum showed strongly correlated with high salinity (≥ 29ppt.) but P. micans indicated a negative correlation with salinity. In Dinophysoids, Dinophysis caudata showed wide salinity tolerance than other species in the group. D. miles, Ornithocercus magnificus, O. steinii and O. thumii showed a strong correlation with salinity. In Gonyaulacoids, Ceratium furca, C. fusus, C. horridum, C. trichoceros, C. tripos, Gonyaulax polygramma, G. spinifera, and Pyrophacus magnificus showed a strong correlation with salinity. In Peridinoids, Protoperidinium depressum, P. oblongum, P. oceanicum, P. pyreforme, and Podolampus palmipes showed a strong correlation with salinity. In Gymnodinoid and Noctilucoid, Gyrodinium estuariale and N. scintillans showed a strong correlation with salinity.
Hamid Reza Soltani Motlagh
Sustainable Marine Structures, Volume 2; https://doi.org/10.36956/sms.v2i2.300

Abstract:
Sustainability is a concept for achieving integration and balance in development, in order to preserve and use resources properly, by providing new solutions to overcome structural, social and economic misconceptions to prevent further degradation and waste of natural resources, and to create a better future for human societies. Sustainable development can be defined as a strategy for the correct use of resources, by modifying and redefining consumption patterns and avoiding one-sided development approaches. Therefore, sustainable development is defined as a long-term and unlimited solution for aligning different concepts (social, economic and environmental), seemingly independent but related and influencing each other. This paper examines the challenges and capacities of the Oman Maritime Community and the role of Maritime Energy Management in terms of sustainable development. To analyze this issue, the role of key players in Oman's maritime industry, such as the Oman Fisheries Company and the Oman Shipping Company, has been studied in relation to the five main indicators of sustainable development goals, including people, the planet, peace, welfare and partnership.
Karim Akbari
Sustainable Marine Structures, Volume 2; https://doi.org/10.36956/sms.v2i2.329

Abstract:
On one hand, the diversity of activities and on the other hand, the conflictions between beneficiaries necessitate the efficient management and supervision of coastal areas. Accordingly, monitoring and evaluation of such areas can be considered as a critical factor in the national development and directorship of the sources. With regard to this fact, remote sourcing technologies with use of analytical operations of geographic information systems (GIS), will be remarkably advantageous. Iran’s south-eastern Makran coasts are geopolitically and economically, of importance due to their strategic characteristics but have been neglected and their development and transit infrastructure are significantly beyond the international standards. Therefore, in this paper, with regard to the importance of developing Makran coasts, a Multi-Criterion Decision Analysis (MCDA) method was applied to identify and prioritize the intended criteria and parameters of zoning, in order to establish new maritime zones. The major scope of this study is to employ the satellite data, remote sensing methods, and regional statistics obtained from Jask synoptic station and investigate the region’s status in terms of topography, rainfall rate and temperature changes to reach to a comprehensive monitoring and zoning of the coastal line and to provide a pervasive local data base via use of GIS and MCDA, which will be implemented to construct the coastal regions
Erkan Oterkus, Sung Wuk Jung
Sustainable Marine Structures, Volume 2; https://doi.org/10.36956/sms.v2i1.311

Abstract:
Nowadays, it is crucial to reduce the cost of the overall project so that the competitiveness of offshore oil and gas without compromising on quality or safety can be achieved. This study investigates how to define the longest cable tray support span considering constructability in order to reduce the number of supports which is a chief cost of a cable tray system. This study presents not only material and geometry frequently used for cable tray but also the formula to estimate the maximum cable load which can be installed within cable tray. To verify the longest span without increasing the strength(thickness) of cable tray, finite element modelling approach was employed based on ANSYS and comparisons were made between numerical analysis and simplified hand calculation. The constructability for the longer span obtained from finite element analysis has been validated in view of manual handling of the cable tray. It is shown that the optimal span suggested in this paper can lead to a better economic benefit without degrading the constructability. For instance, as the span is longer, the cost of material as well as construction manpower can be saved. It is also expected that this approach will contribute to enhance the competitiveness of offshore oil and gas.
Mohideen Wafar
Sustainable Marine Structures, Volume 2; https://doi.org/10.36956/sms.v2i1.291

Abstract:
Data obtained on hydrography and currents in meridional sections in Gulf of Aqaba and Red Sea in November 2013 and March 2015 were used to determine the extent of contribution of Gulf of Aqaba Water (GAW) to formation of Red Sea waters. The southward flow across the Strait of Tiran was ~0.02 Sv in both periods which is direct evidence of significant contribution of GAW to Red Sea waters in autumn-winter. A multiple tracer analysis using temperature, salinity, and dissolved oxygen showed that the GAW, on entry into Red Sea, bifurcates into two branches. The upper branch exiting the Strait in the depth range 150-220 m has densities between 28.3 and 28.5, continues to flow at the same depths, and feeds the Red Sea Overflow Water (RSOW). The lower branch that exits between 220 and 250 m above the sill cascades down its southern face, mixes with northward recirculating branch of Red Sea Deep Water (RSDW) and sinks to the bottom and forms part of southward-flowing RSDW. Contribution of GAW to northern Red Sea waters below 100 m depth was 36 ± 0.4% in November 2013 and 42.1 ± 5.4% in March 2015. GAW is traceable down to 17-19 °N in RSDW and RSOW. Volume contribution of GAW to RSOW was 9.6 * 1012 m3, about 50% higher than that for RSDW (6 * 1012 m3). Analyses of the data from R.V. Maurice Ewing cruise in 2001 gave similar results and lend support for these deductions. Indirect estimates suggest that contribution of GSW to deep water formation could exceed that of GAW.
Maycon Da Silveira Paiva, Leonardo Da Silva Silveira, ,
Sustainable Marine Structures, Volume 2; https://doi.org/10.36956/sms.v2i1.306

Abstract:
The present study aims to analyze the state of the art of scientific studies about the Overtopping device used to convert sea wave energy into electrical energy, by means the Bibliometric Methodology. The development of this study took place through the selection of articles from conference proceedings, as well as national and international journals. The Bibliometric methodology consists of a statistical tool that allows quantifying the measurement of production indexes. Using selected keywords, it was conducted a survey of studies in the online databases of Science Direct, SciELO and Google Scholar. The works found then went through a filtering process, in order to limit the bibliometric study only to studies about Overtopping devices as sea wave energy converter. Finally, the investigation of these selected articles was carried out under the optics of production and authorship study, content study and study of bibliographic references. Where it was identified growth in publications related to the topic, methodologies used and, among other indicators, the authors most cited in the analyzed articles. The predominant keywords used were “Wave Energy Converter” and “Overtopping”. It was noted that Brazilian universities are leaders in the productivity, presenting more than 36% of the scientific production regarding Overtopping WECs.
Fuat Kara
Sustainable Marine Structures, Volume 2; https://doi.org/10.36956/sms.v2i1.264

Abstract:
The numerical predictions of the hydroelasticity of floating bodies with and without forward speed are presented using a direct time domain approximation. Boundary-Integral Equation Method (BIEM) with three-dimensional transient free surface Green function and Neumman-Kelvin approximation is used for the solution of the hydrodynamic part and solved as impulsive velocity potential whilst Euler-Bernoulli beam approach is used for the structural analysis with analytically defined modeshapes. The hydrodynamic and structural parts are then fully coupled through modal analysis for the solution of the hydroelastic problem. A stiff structure is then studied assuming that contributions of rigid body modes are much bigger than elastic modes. A rectangular barge with zero speed and Wigley hull form with forward speed are used for the numerical analyses and the comparisons of the present ITU-WAVE numerical results for response amplitude operator, bending moment, shear force etc. show satisfactory agreement with existing experimental results.
Saleem Mustafa, John Hill, Sitti Raehanah M. Shaleh, Abentin Estim, Zarinah Waheed, Madihah Jafar Sidik, Chen Cheng Ann, Rossita Shapawi, Lim Leong Seng
Sustainable Marine Structures, Volume 2; https://doi.org/10.36956/sms.v2i1.238

Abstract:
The Novel Coronavirus outbreak that originated in Wuhan city of China in December 2019 assumed the global pandemic proportions during 2020. The disease it causes (termed as COVID-19) has created an unprecedented public health crisis, taken 1,324,461 lives so far, infected 54,817,231 people around the world, battered the global economy and paralyzed the normal activity. The world has been pushed into recession with resulting long-term financial hardship and social misery for all and global goals of development have been challenged. This situation is evolving so rapidly that the data on numbers of infections and deaths are changing daily and the economic impacts are difficult to evaluate at this stage and probably will not be exactly known in the near future. There will be domino effects of the containment and mitigation measures that will be implemented for years to come. It is important to determine the genesis of the outbreak to understand the root causes of COVID-19 and to prevent such pandemics from occurring in the future. It is believed that the virus originated in a seafood market in Wuhan that was also trading in wildlife for human consumption. Such practices are associated with the habitat degradation and biodiversity loss, leading to an imbalance of the natural ecosystems. The zoonotic spillover of this infectious outbreak is a reflection of this impairment of natural systems. While concern for biodiversity is fairly widespread, its practical translation into conservation action is slow. One strategy is to invest more efforts into linking biodiversity with issues that affect daily life such as food security, public health, economy and the general wellbeing of the societies. In addition, the role of oceans, whether direct or indirect, must be examined and recognized. Scientific and anecdotal evidences demonstrate the significance of marine critical habitats in combating and containing human diseases. Marine bioprospecting for antiviral compounds in many marine organisms can lead to identification of organisms possessing curative properties that can be used to treat the COVID-19 patients until vaccines are developed and made available. There are many other ways in which the oceans can help in human health. In addition to providing an analysis of the COVID-10 outbreak, this paper also suggests knowledge-based and informed measures that need to be applied to prevent a repeat of such catastrophic events while highlighting the role of oceans in this context. However, the Covid-19 pandemic is a unique phenomenon and the current models relating to its growth and development are limited both in terms of credibility and effectiveness. Thus, a serious introspection is needed to holistically investigate the consequences of COVID-19 as the world moves towards rebuilding the economies and societies. The disruption of supply chains, the closure of industries, the collapse of domestic and international travel, coupled with widespread unemployment, are some of the most visible disruptions to normal living. The growth, societal paradigms and existing systems of governance should be up for a review. Plans and strategies for recovering the global economy and ensuring its resilience will require incorporating natural and ecosystem restoration in conjunction with implementing the concept of sustainable living. In this context, sustainability of the oceans is a key consideration in the development of a framework for post-COVID-19 recovery and this aspect is the major focus of this paper.
Bing Wang
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i2.116

Abstract:
Composite materials are lightweight structures and have been wildly used in marine applications. A carbon composite structure usually absorbs moisture while in-service, which can significantly affect its properties, and detriments the overall performance. We perform a detailed study on moisture absorption and diffusion of a carbon fibre reinforced vinyl ester resin composite system. Composite samples are immersed directly in four different solutions at a temperature of 37±0.5℃ for 1444h. The moisture diffusion is analysed through the Fickian diffusion model; the diffusion parameters are subsequently determined from the gravimetric data. The moisture absorption and interaction with the composite constituents are then discussed. These indicate the fundamentals of the moisture absorption and diffusion within the carbon composite structure.
Seyed Majid Mosaddad
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i2.95

Abstract:
Persian Gulf (PG) is a semi-enclosed water basin that is connected to the Gulf of Oman through the Strait of Hormuz. There are different forcing and climatic parameters influencing the thermocline development in the PG from winter to summer. These factors include tide, river inflow, solar radiation, evaporation, northwestern wind, and water exchange with the Gulf of Oman. In fact, the thermocline, which is often observed in the oceans and open seas, can be considered as a seasonal phenomenon in the ocean. In the present study, it is studied theoretically; and compared with the results of the Princeton Ocean Model (POM) in the PG. During winter to summer, solar heating created an intense thermocline that decoupled the surface mixed layer from the interior water. The data are reviewed as the measurements collected in 1992 and recent modeling results. Overall, through a theoretical study, it is concluded that thermocline formation is a seasonal phenomenon in the PG.
Lan Dinh Tran, Do Gia Khanh, Do Thi Thu Huong, Vu Duy Vinh
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i2.141

Abstract:
The fast growth of Hai Phong ports in the two last decades requires not only their upgrading facilities but also expanding port area and dredging their shipping channels (existing and new ones) that generate a huge amount of unreused dredged materials. While all existing dumping sites in sea waters and onland get over capacity, looking for new dumping sites in sea waters is an urgent need. This study is to zone coastal waters of Hai Phong for suitable dumping sites meeting sustainable coastal management. Multi-criteria overlay analysis on GIS platform was employed with criteria of natural conditions, environment and socio-economics for zoning coastal waters of Hai Phong. These criteria were detailed into eight sub-criteria and then developed to eight GIS weighted thematic sub-layers of bottom depth, litho-hydrodynamics, ecosystems, distribution of benthos, distance to residential areas and tourist sites, distance to aquaculture area, distance to ecosystems and distance to conservation areas. Analysis results show the highly suitable zones for dredged material dumping in South, South West Hai Phong at depth below 15m to the deeper areas. Disposals of dredged materials in the zones would minimize impacts on the environment, ecology and socio-economics in surrounding waters and coastal areas.
Seyed Majid Mosaddad
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i2.28

Abstract:
The Persian Gulf (PG), as a semi-enclosed water basin extends in [47-57] E, [24-30] N, geographic domain. Particularly, northern part of the PG shows more baroclinicity and turbulence because of the river inflow from the Arvand, bottom and costal stresses. Furthermore, wind stress has many effects rather than in mid deep domain of the PG. Thermocline development in the PG is observed because of studying the data measured in the Mt. Mitchell cruise in 1992 by different models from winter to summer. The studied turbulence in the northern part of the PG is navigated from winter to summer due to the internal wave’s activity and stability intensified through water column.
T H Ranahewa, A. D. Premarathna, R.M. K.K. Wijesundara, V. Wijewardana, A. P. Jayasooriya, R.P. V.J. Rajapakse
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i2.94

Abstract:
Seaweed is an enormous resource comprised with natural bioactive compounds comprise with several therapeutic effects including anticancer activity. In this context, the biochemical composition of seaweeds plays a major role. Many biochemical compounds extracted from seaweeds and crude extracts, such as aqueous, methanolic account mainly for the anticancer effect against several cancer cell line. In this contrast seaweed extracts inhibit cancer cell growth and proliferation by inducing apoptosis and inhibit metastasis activity. In this review, biochemical and anticancer properties of seaweeds are discussed and this will provide the basic information to develop a novel chemotherapeutic drug to challenge the cancer.
S Surendran, G L Manjunath, S K Lee
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i1.1

Abstract:
Preventive maintenance is an accepted practice in engineering to keep the structural reliability of ship hulls at the highest possible level. Designers ensure a longer period in between the consecutive maintenance of ship hull parts to optimize expenditure. This is relevant in view of the difficulty in reaching farthest corners in ballast tanks, fuel storage tanks, cofferdams etc. Prior maintenance of the deck and hull parts save a considerable amount of the owner’s budget.A portable technology like patching becomes more handy and economic. Performance of both unpatched and patched samples during dynamic loading conditions being examined in the present investigation. The high strength steel panels with a dimension of 70mm×15mm×3mm were edge cracked for lengths of 4mm and 7mm, with width of 1mm for both. The edge cracked high strength steel panels are repaired with composite patches using GFRP (glass fiber reinforced plastic), CFRP (carbon fiber reinforced plastic) and AFRP (aramid fiber reinforced plastic). The patching was done by 3 and 5 layered and impact tested by Charpy impact tester at ranges of high temperatures. The amount of energy absorbed in the impact is converted to dynamic fracture toughness values and compared for evaluating the performance of FRP (fiber reinforced plastics). Finite element analysis was done for evaluating the stress intensity factors at different types of patching and testing conditions. Comparatively the AFRP patched samples showed better dynamic fracture toughness values at different temperatures.
Sivabalan Ponnappan, Surendran Sankunny
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i1.4

Abstract:
Moonpools are openings right through the hull from continuous deck to bottom of the ship, allowing equipment or mini-submarines to be put into the water at a location on the vessel with minimum ship motion. Open moonpools in a drillship are causing additional resistance when the ship is in forward speed. It was shown that the water inside the moonpool started to oscillate at forward speed. The water mass in the moonpool is subjected to sloshing and piston modes. The vertical motion is piston mode and the longitudinal one is called as sloshing mode. This water particle motion inside the moonpool is mainly depended on the geometry, moonpool depth, and encountered wave frequency. Out of this, moonpool geometry is one of the key factors for the performance of the moonpool. The varying cross-section geometry is one of the practically possible and economically feasible solutions to reduce the oscillation to a considerable level is attempted in this paper. Also the resistance caused by the moonpool and the free surface generated around the hull is investigated with the use of computer simulation.
G L Manjunath, S Surendran
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i1.3

Abstract:
Tropical waters are with more salinity and harbor millions of micro organisms. Such environmental condition challenges the strength and reliability of marine structures. The behaviour of structural materials due to pitting and uniform corrosion is studied, and a method based on coating is suggested to improve the life cycle ensuring reliability in its functionality. The structural materials like high strength steel and AA6063 were selected for the study and metallic coating performed for evaluation of corrosion resistances. Samples are investigated in chloride concentration of 3.5% NaCl by weight loss measurements and potentiodynamic polarization. The coating was done by electroplating and PVD (Physical Vapour Deposition) method for high strength steel, where as aluminum samples were coated by an electroplating method. The high strength steel samples were mono coated by Ni and Cr using the electroplating method, and composite coating was done with Al-N (Aluminium nitride) and Ti-Al-N (Titanium Aluminium Nitride) by PVD techniques. Scanning electron microscopy (SEM) was used for evaluation of fracture toughness of coating around the pits formed. The investigation showed that the methods and thickness of coating influenced corrosion resistances of the substrate metals. Composite coated samples by PVD showed excellent corrosion resistance properties compared to electroplated samples after the investigations. Finite element analysis was performed by FRANC 2D/L (Fracture Analysis Code) showed a decrease in stress intensity values for composite coated samples of PVD compared to mono coated electroplated samples. Increase in the duty cycle of the structure was observed in the simulation has a result of a decrease in stress intensity values for PVD coated samples.
M Vishnu, S Surendran
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i1.5

Abstract:
Wind energy is considered one of the most promising alternative energy sources against the conventional fossil fuels. However, the deployment of these structures in deep-water for better power production is considered as a complex task. This also has raised the issue regarding selection of appropriate support structures for various sea conditions by considering environmental impact and carbon footprint. This paper considers a jacket like support structure as a case study for an intermediate water depth (50m). The jacket is considered to be located in North of Dutch Sea, and 100-extreme wave is applied as load condition. Here, the presented methodology provides an insight towards environmental/social impact made by the optimized designs in comparison with reference design.
S. Surendran, S. K Lee
Sustainable Marine Structures, Volume 1; https://doi.org/10.36956/sms.v1i1.2

Abstract:
A ship manoeuvring problem is solved using an algorithm built on fuzzy logic. The manoeuvring model for a design ship is coded in C++ and the results are presented here. A bulk carrier is assumed as design ship for a newly setting up harbor along the east coast of India. The harbor mouth is 25 km away from the deep water zone. The approach channel is straight along the 22 km length. Laterally restricted and shallow waters are considered and their influences on hydrodynamic derivatives are discussed. Some sample problems are solved. Trajectories, ship heading, rudder angle, velocities and accelerations, of the moving vessel, are calculated and presented for clarity. The developed code is robust in the sense that any designer or user can easily interact with various input parameters to verify the outputs and their suitability for the design ship meant for a particular water front location. The results are validated using another algorithm built on PID which is discussed in brief.
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