Journal of ETA Maritime Science

213-213

Authors: Selçuk NAS

We are pleased to introduce JEMS 8(4) to our valuable followers. There are valuable and endeavored studies in this issue of the journal. We hope that these studies will contribute to the maritime industry. I would like to mention my gratitude to authors who sent their valuable studies for this issue, to our reviewers, to our editorial board, to our section editors, to our foreign language editors who provide quality publications by following our publication policies diligently and also to layout editors who spent great efforts in the preparation of this issue. Your Sincerely.

242-251

Authors: Thaddeus Chidiebere Nwaoha, Sidum Adumene

The need to understand the associated risks of pressurized vessels and their consequences onboard ship is imperative. The handling and storage of Liquefied Natural Gas (LNG) mostly result in catastrophic accident with associated consequences. To quantify these consequences in terms of death and degree of burn depends on the tank structures and pressure control mechanism onboard LNG carriers in a harbor. In this research, the result of the potential risks and damage consequences of the LNG fire accident in terms of the degree of burns and fatality is presented. The probability of death, first and second degree of burn injuries are assessed using consequence modelling technique, while the pool fire was modelled using the Boiling Liquid Expanding Vapour Explosion (BLEVE) approach. The result shows that at 30 meters from the flame radius, the probabilities for first-degree burn, second-degree burn, and death decrease, respectively. A sensitivity analysis revealed that at the initial heat flux and closer distance of 5m to 10m from the flame radius at the point of the accident, the death rate, first degree, and second-degree burns increase significantly. Therefore, installing a safety system and best practices that will mitigate these risks to as low as reasonably possible should be incorporated into the system design.

274-285

Authors: Yusuf Genç, Murat Ozkok

As well known, ships which have complex production processes are subject to various tests made on every stage in many fields from the beginning to the end of the production. After the tests are completed successfully, the ship is delivered to the ship-owner. “Sea trial” being the last stage of these tests, is examined in detail in this study. The purpose of this study is to plan the tests performed in the sea trial by the means of computer programs and to suggest shorter completion period for the tests. Thus, reducing the total cost of the cruising. Moreover, shortening the duration of the cruise will be a factor that can speed up the delivery of the ship. For this purpose, the tests and processes performed during the sea trial are listed. A cruise process flow diagram including all the tests applied under normal conditions was created, and the data were entered into the SIMIO simulation program. As a result, it was determined that the total cruising time was 28,0989 hours. After that, a new flow diagram was created by making some improvements in the current testing process, and a new simulation model was built up. In the new simulation model, total time spent to complete the tests were 25,3567 hours, so the testing time was shortened by 2.75 (9,76%) hours.

302-308

Authors: Ahmet Yaşar CANCA, Görkem Kökkülünk

Sulphur 2020 regulation as a reduction of sulphur emissions has been caused a big challenge via using new fuels in the maritime industry. Consistent changes in the chemical and physical properties of these new fuels make classical maintenance methods as brake down or planned inadequate and endanger operational and navigational safety on ships. Within this framework, ship maintenance systems need to be reevaluated in accordance with the new marine fuels. In this study, firstly impacts of new marine fuels on ships have been evaluated by means of a literature review. Furthermore, repair and maintenance systems have been presented that are currently used on board ships. Subsequently, advantages of a predictive maintenance system that will reduce risk by constantly monitoring the potential critical characteristics of VLSFO over other maintenance systems have been discussed. Then, assessments of compliance fuel have been done in accordancewith fuel properties, problems and corrective actions. Lastly, discussions and suggestions have been provided to the ship owners and technical managements.

133-133

Authors: Selçuk NAS

Journal of ETA Maritime Science (JEMS), published by UCTEA Chamber of Marine Engineers, started its academic career in 2013. It first indexed in the DOAJ in 2014 and proved its quality. Later in 2016, it entered into the “Index Copernicus” citation index. In the same year, it was entitled to enter into TUBITAK TR indexes. Finally, we are pleased to inform you that “Journal of ETA Maritime Science (JEMS)”, published by UCTEA Chamber of Marine Engineers, has been selected for coverage in Clarivate Analytics products and services of WoS. JEMS will be indexed and abstracted in Emerging Sources Citation Index (ESCI). There is an Editorial Board behind this short story of JEMS’s full of success. This board members consist of highly qualified academics from different nationalities and fields, working with great devotions all around the world. In addition, the Associate Editors of JEMS, consisting of young academicians who prepare JEMS for publication four times in a year, are voluntary servants of the JEMS. Besides, the Authors who generate the journal's intellectual capital by sharing their valuable researches in JEMS have a great share in these successes. The entry of JEMS into the Web of Science Emerging Sources Citation Index (ESCI) has welcomed by the Board of UCTEA Chamber of Marine Engineers. This success will increase the attractiveness of JEMS and enable the selection of the best quality articles among many more quality articles. In this issue, we present to your attention two remarkable articles highlighting the issue of “women and sea”. In addition, we present an impressive article about the scope and academic perspective of polar research prepared by Prof. Dr. Ersan Basar in the academic perspective section of our journal. We also thank him for the cover photo of this issue.

150-160

Authors: Donatus. E. ONWUEGBUCHUNAM, Moses. O. APONJOLOSUN, Sodiq. O. BUHARI, Dotun OJO

This paper assessed the performance of jetty operations in Warri Refining and Petrochemical Company (WRPC). Primary data for the study consisted of ship turn round times, volume of cargo and number of vessels handled at the jetties for years 2004 to 2018. These variables served as key performance assessment criteria. In addition, copies of questionnaires on postulated factors affecting terminal performance were administered to a random sample of WRPC staff. Our findings showed that the jetties were being operated at less than optimum level. Trend analysis of the key performance indicators showed existence of continuous decline in operational performance of WRPC over the years covered in the study. Significant factors accounting for this performance outcome were found to include: inadequate berthing facilities, shortage of manpower supply, pipeline vandalisation, inadequate maintenance of jetty facilities and poor documentation process. The study recommended deployment of trained workforce to jetty operations, maintenance of berthing facilities, adequate funding and improved documentation of processes during jetty operations.

178-193

Authors: Oktay YILMAZ

Crossflow over cylindrical structures has been extensively studied by both academia and industry in various fields. It is responsible for in-line and transverse vibrations of marine risers. Flow-induced structural vibrations may end up with the failure of these tubular systems in oceans and seas. First experimental studies in literature signified that longitudinally grooved cylinders inspired by Saguaro trees may offer reductions both in drag and lift forces. In the present study, the performance of 2 dimensional (2D) unsteady Reynolds averaged Navier-Stokes (URANS) simulations is tested in predicting hydrodynamic force coefficients of cylinders. First, CFD runs are conducted on a smooth cylinder and a cactus-like cylinder in literature. Then flow over 8-, 10-, and 12-grooved cylinders with a diameter of 0,5 m are solved to analyze flow features in detail and evaluate the capability of 2D URANS solver for the problem at hand. k-ω SST turbulence model is employed in URANS solver. It is shown that as the number of grooves increases, mean drag slightly decreases and amplitude of drag decreases by 29%. Separation angle is significantly improved with a number of grooves from 92o to 120o. However, the amplitude of lift force increases with the number of grooves with reference to 2D CFD simulations.

210-212

Authors: Ersan BAŞAR

85-85

Authors: Selçuk NAS

We are pleased to introduce JEMS 8(2) to our valuable followers. There are valuable and endeavored studies in this issue of the journal. We hope that these studies will contribute to the maritime industry. I would like to mention my gratitude to authors who sent their valuable studies for this issue, to our reviewers, to our editorial board, to our section editors, to our foreign language editors who provide quality publications by following our publication policies diligently and also to layout editors who spent great efforts in the preparation of this issue. Your Sincerely.

98-113

Authors: Burak GÖKSU, Kadir Emrah ERGİNER

Maintenance practices are considered as the means of providing safety and security to environment and quality service, and despite increasing the costs for companies with certain increments, they contribute to their reputation and reliability. Maintenance planning of ships consists of setting priorities and planning the efficient use of the sources. One of the main objectives of this study is to bring up more profits from commercial activities by optimizing the availability of vessels. Operational capacity is ensured by adopting a systematic and proper maintenance policy that increases effectiveness and efficiency by reducing downtime. To reach at such a target, recent failure data is analyzed and through this analysis certain procedures are developed for spare parts availability and these procedures are utilized in maintenance applications. This study aims to provide an additional feature for predictive maintenance software for the analysis of the upcoming conditions of the main engine systems. In this study, the history of failure in the critical nine main engine related subsystems have been analyzed by artificial neural network method, which is consistent with condition-based maintenance applications and subsequently helps to bring out the potential breakdowns in the recorded history of failure.

1

Authors: Selçuk NAS

We are pleased to introduce JEMS 8(1) to our valuable followers. There are valuable and endeavored studies in this issue of the journal. We hope that these studies will contribute to the maritime industry. I would like to mention my gratitude to authors who sent their valuable studies for this issue, to our reviewers, to our editorial board, to our section editors, to our foreign language editors who provide quality publications by following our publication policies diligently and also to layout editors who spent great efforts in the preparation of this issue. Your Sincerely

10-21

Authors: Hüseyin ELÇİÇEK, Bülent GÜZEL

Over the last decade, UV disinfection technology has been widely employed in the disinfection of nonnative species in wastewater and process water treatment. In this study, we assessed the feasibility of the adoption of a Taylor-Couette UV reactor in disinfection of unwanted species commonly found in ballast water. With this purpose, glycerol solutions were used in a Taylor Couette reactor with two different radius ratios. The observed flow structures and the critical transition values were simultaneously compared with each other and literature. Emergent flow structures in TC reactors provide considerable improvement in axial and radial mixing of particles and increasing the efficiency of the disinfection of E. coli. The obtained results show the possibility of utilizing the Taylor-Couette UV reactors as an alternative method in inactivation of non-native species in the ballast water.

38-52

Authors: Kubilay BAYRAMOĞLU, Mustafa NURAN

Fossil-based fuels have been decreasing all over the world and the energy requirements of power generation systems are increasing. Diesel engines are one of the most common and efficient power generation systems. However, national and international organizations impose various restrictions to reduce emissions from diesel engines. Reducing emissions and improving performance in diesel engines are one of the most common areas of work. Improvement of performance and emission parameters is possible with changes in alternative fuels, engine geometry and fuel injection systems. In this study, the effects of different injection timing and injection duration on diesel engine performance and exhaust gas emissions have been investigated with computational fluid dynamics (CFD) method. The numerical study has been carried out on a 4-stroke, single cylinder test engine and the results have been compared with the experimental results obtained from the literature. As a result of the study, combustion chamber speed profiles, fuel mass change, temperature, pressure, chemical heat release rate has been determined for the standard operating conditions. Parametric study has been performed for different injection timing and injection duration of engine. For each case, performance and emissions parameters have been determined. Analysis results has compared, and the most suitable injection parameters has been introduced.

66-84

Authors: Mehmet DOYMUŞ, Gül DENKTAŞ ŞAKAR

IMO 2020 regulations force maritime industry to look for alternative fuels for compliance. LNG is a promising option as a fuel considering today's emission control regulations and for measures to be adopted in the future. However, supply chain development for small-scale LNG is not at the expected level. The study examines the development of LNG bunkering supply chain based on different perspectives of stakeholders. The research explores the challenges regarding LNG bunkering development and aims to provide suggestions to overcome these challenges. Semi-structured interviews were conducted through purpose sampling including various representatives of LNG bunkering supply chain. The study identifies barriers in LNG bunkering development, categorizes some key approaches and links challenges from the view point of relevant stakeholders for improvement in supply chain. The research findings indicate that collaboration of stakeholders is the main driver for LNG bunkering development, public opinion, standardisation and transparency are the other outstanding factors to improve LNG bunkering supply chain.