Items

  • OIL LEAKAGE SIMULATION AND SPILL PREDICTION NEAR ODESSA HARBOR

    George Laurentiu DUMITRESCU; Ionut VOICU; Fanel-Viorel PANAITESCU; Mariana PANAITESCU
    10/1/2015
    1 citation
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The paper presents a computer simulation of an emergency situation generated from an oil spill, inside Odessa harbor, using the software POTENTIAL INCIDENT SIMULATOR EVALUATION AND CONTROL SYSTEM (Pisces II), who it is especially designed for assessing the consequences of oil pollution on sea water.
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  • STATISTICAL MODEL OF A LNG TERMINAL – WAYS OF IMPROVING THE LNG TERMINAL EFFICIENCY

    Dimitar DIMITRAKIEV; Rumen GROZEV
    10/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The best way of improving the efficiency is to create a basic statistical model which can be used in the future for optimizing the work of a new terminal in the near future. The proposed model represents LNG terminal as queuing system. The model created is basic one but can be used as good foundation for creating a more sophisticated model once the main characteristics of the a new LNG terminal are known.
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  • PROBABILISTIC METHODS OF DECISION MAKING IN SHIPPING ACTIVITIES

    Dimitar DIMITRAKIEV
    10/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    When studying a large number of phenomena and processes, researchers strive to create simple patterns. From the wide variety of factors separate the main and the rest are considered secondary and ignored. Very often, in practice, in making management decisions in the presence of many options is the task to recalculate the probability of each hypothesis, once it has been observed event. Such circumstances can be decided by the theorem to verify the hypotheses (Bayesian formula) obtained as a consequence of the theorem for multiplication formula for the total probability. Bayesian formula can calculate conditional probabilities of each hypothesis, then most likely of them is taken as the basis for future action. To obtain the practical utility of the theorem to check the hypothesis, we examined two cases of decision arising in shipping activity.
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  • APPLICATIONS IN MATLAB USING FINITE ELEMENT METHOD

    Iulia-Alina ANTON; Mariana PANAITESCU; Fanel-Viorel PANAITESCU
    10/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Finite Element Method (FEM) is based on the concept of building complex objects using simple elements or division in small parts of complex objects easily manipulable. This paper presents the modeling equations of fluid and thermal analysis, namely equations type: hyperbolic, elliptical parabolic. It will be noted that it is important to know every step of the method as the main stage is the development model for calculating the structure. Other important steps are the domain meshing and interpolation process of meshing with the effect sharing model structure in a certain number of pieces called finite elements. Here, we will present three types of equations modeling using Matlab. Finally, we notice that there are several programs that are based on MEF instead with a user-friendly interface. Even here it is necessary to understand the method steps in order to properly model the model chosen.
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  • THE MATHEMATICAL DESCRIPTION OF THE PROCESS OF OIL SPREADING ON THE WATER SURFACE

    Ionut VOICU; Laurentiu George DUMITRESCU
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The aim of this paper is to study and explain the spreading of oil on the water surface. Oil spills in sea waters are serious environmental disaster often leading to significant and long-term impacts on the sensitive aquatic systems. Having a detailed knowledge of oil slick behavior on water can be important in making operational decision and taking appropriate action against pollution. When crude or refined oil products are spilled on the sea, they are spread to form an oil slick. The slick spreads over the water surface due to a balance between several forces. A number of natural processes take place, which disperse the oil and change its chemical and physical properties.
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  • UTILIZATION OF RESOURCES ON TECHNO-NAUTICAL SERVICES BY DEVELOPING A DYNAMIC SIMULATION MODEL: AN APPLICATION ON THE PILOTAGE SERVICE IN ISTANBUL STRAIT

    Lect. Capt. Emre UCAN; Assoc. Prof. Dr. Selcuk NAS
    4/1/2015
    2 citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    In Turkey, techno-nautical services’ principles are determined in Port Regulations prepared by Turkish Transportation, Maritime Affairs and Communication Ministry. But the principles are set mostly empirically or experience based. This study helps decision-makers and stakeholders for the correct utilization of resources on technonautical services by developing a dynamic simulation model. For this purpose, the pilotage service algorithm has been developed according to structured interviews with pilots, with statistical data of Traffic in Bosporus and all rules and regulations in effect on the waterway. It is found out that by the designed algorithm, it is possible to make correct decision about the required human resource as pilots even in a complex system as in Istanbul Strait. And due to dynamic nature of algorithm with application of simulation software different scenarios can be evaluated easily.
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  • MODEL OF PROCESS OF PORT INFRASTRUCTURE SAFETY MANAGEMENT

    Evgeniy RUDENKO
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The article presents a model of process of port infrastructure safety management, based on proactive approach, which is defined as an activity, directed on maintenance and improvement of the future state of port infrastructure safety. Model is directly related to the adoption of project decisions, because provides the concordance of the put aims and chosen strategies through their realization. Proactive management is one of the basic principles of port infrastructure safety management, laid down in the proposed model. Proactive approach to port infrastructure safety management involves planning strategy of this activity by formation of a portfolio of projects that achieve strategic objectives of port safety improvement program. Proposed model of port infrastructure safety management allows effectively manage the current state of port infrastructure safety through measures aimed primarily at reducing the probability of an emergency, as well as to forecast and evaluate the future state of port infrastructure safety with regard to its development.
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  • DEVELOPMENT OF MATHEMATICAL MODEL FOR HUMAN RELIABILITY ASSESSMENT

    Sabina NEDKOVA
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The assessment of the human reliability is an attempt to predict the behavior and the attitude of the man, which could lead to the realization of a critical situation. This is a complex process, mainly due to the fact that unlike machines which failures are predictable and easy to be identified because of the exact parameters that the process must have at any point in its development, when dealing with people, we cannot speak of "failures” in the purely technological sense of the word. Some of the most important reasons for that are: that the people’s work is often described qualitatively, but not quantitatively; in most of the cases the action carried out by a human is part of a process shaped by the actions of other people involved in it; and in the complex of factors, physical and psychological, personality-related, qualifications, experience and knowledge, as well as the environment and the nature of work, which affect the human in the performance of his duties.
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  • A POINT OF VIEW ON THE THEORY OF OPEN CYCLE GAS TURBINES

    Feiza MEMET
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    In the context of the high interest on the concept of energy, engineering education has to adapt to the modern technical requirements. In this respect, marine engineering, as a part of engineering education is facing curricula changes. This paper deals with an attempt related with the improving of the teaching syllabus of the discipline called Thermodynamics / Part 1, included in the curricula of future marine engineers, enrolled in Constanta Maritime University (CMU). More exactly, it is about the theory of open cycles of gas turbines. The need of improving this theory came from the fact that in the last decades, this technology became more and more attractive for different industries. Maritime industry is one of these, where it is registered a high interest for thermal performance improving. Thus, if the classic theory of open cycles gas turbines was based on considering the working fluid to be a perfect gas, having constant specific heats, the new approach is discussing the case of irreversible cycle and specific heats of air and flue gas depending on temperatures. Results the need of a new hour allocation. This theoretical basis is allowing a more detailed thermal efficiency evaluation and assessment of specific fuel combustion.
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  • VELOCITY OVER THE TARGET SURFACE AND PRESSURE FOR A NUMERIC GEOMETRY OPTIMIZATION OF AN WED

    George MARTINAS; Andreea ARSENIE; Marinel Danut LAMBA
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The pressure on ships designers to achieve both reduced fuel costs and reduced emissions by optimizing the hull and propeller has never been higher. Being one of the key strategic business goals for ship owners and operators, the reduction of fuel cost becomes essential; and furthermore a variety of recent legislations require owners and operators to move towards the reduction of emissions from ships of SOx, NOx and CO. There has been great interest in the potential to enhance the performance of existing vessels through retrofit of devices to the hull, in parallel to the performance improvement of new built vessels. The Wake Equalizing Duct (WED) device must be customized to fit to the afterbody of the ship in terms of performing its supposed function as Velocity over the Target Surface and Pressure. The Designer is therefore placed in the front of multiple geometric solutions from between he has to make a choice. A given geometry of a WED device is taken and via Design Optimization the geometry of the duct was refined so that better results are achieved with a smaller and more compact WED. A rational choosing approach by involving the numeric optimization of the geometry of the WED in order to select the best fitted WED to perform the best in order to achieve some predefined parameters is targeted in this papers.
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  • TWO ZONES THERMODYNAMIC MODEL FOR HIGH SPEED MARINE DIESEL ENGINES

    Dawwa MAHRAN; Paul BOCANETE
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    In this paper two-zone thermodynamic model has been used for modeling the combustion process in direct injection diesel engine based on the results of modeling the combustion process by using single zone thermodynamic method. Single zone thermodynamic method depends on the average value of in-cylinder temperature and pressure, which considered one of the main defects of using one-zone thermodynamic model. Hence, developing a new model is very necessary especially for better description of the in-cylinder peak temperature during the combustion process. The concept of two-zones thermodynamic model is based on dividing in-cylinder gases in two zones the first zone is unburned zone which contains fresh air and the injected fuel, and the second zone is burned zone which is formed from combustion products with high temperature. The importance of the two-zone thermodynamic model is using it to calculate and to model Nox emissions. The formation of Nox emissions highly depends on the in-cylinder peak temperature. Hence, the more accurate results in modeling the temperature of in-cylinder gases lead to obtain more accurate results in modeling Nox emissions
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  • MODELLING THE HEAT TRANSFER PROCESS DURING THE COMBUSTION IN MARINE HIGH SPEED DIESEL ENGINES

    Dawwa MAHRAN; Paul BOCANETE
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The heat transfer in marine diesel engines is a complex phenomenon that occurs by two main components, the connective and radiative components under varying conditions such as temperature, pressure, and composition of incylinder gases. Hence, modeling the heat transfer phenomenon during the combustion process in high speed marine diesel engine imposes many difficulties in determining the heat flux through the combustion chamber walls. Many researches have been carried out many studies to understand and to model this phenomenon. Since modeling this phenomenon is an important step for modeling the whole combustion process which takes place inside the combustion chamber, many models and correlations of these models have developed for modeling this it in satisfied results and in a relative short time. This work concentrates on the two main methods for modeling the heat transfer in diesel engines which they are Hohenberg, Woschni and their correlations, with the use of MATLAB program for numerical modeling.
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  • APPLICATION OF SOME NEW POWER QUALITY INDICES IN ANALYSIS OF THE SHIPBOARD ELECTRICAL SYSTEM EFFICIENCY

    Ginka IVANOVA; Valentin GYUROV; Rumen KIROV; Bohos APRAHAMIAN
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Improving the quality of electricity and electromagnetic compatibility is a topical issue in shipboard electrical power systems as these concern two main technical aspects. First is to improve the electromagnetic compatibility, which leads to improvement of the operating modes of the equipment and thus increase of the overall reliability of the system. Second aspect is related to the quality of electricity leading both to increase in overall reliability and refinement of measures to reduce the power and energy losses. The latter is particularly relevant, since it is directly related to saving primary energy sources - liquid fuels, and this in turn leads to reduction of greenhouse gas emissions. This paper focuses on the possibilities of using some new quality indicators of electricity and electromagnetic compatibility, which are not regulated by normative documents. Practical software application has been developed in MathCAD Prime 3.0 environment and its use is shown in experimental studies of cruise ship class 1A1.
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  • COMPARATIVE APPROXIMATE STUDIES ON THE SHIP’S ROLLING MOTION

    Dumitru DELEANU
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The new geometrical and analytical techniques of nonlinear dynamics offer to the naval engineer ideal tools for studying the ship dynamics and stability. Between them, the bifurcation diagram, the Poincare map, the phase plane, and the time histories are considered in the paper in an attempt to demonstrate the low period solutions of the asymmetric roll equation derived by Kan and Taguchi. The model assume a linear damping, a restoring moment represented by a third-order polynomial and a single frequency harmonic excitation. For moderate forcing amplitudes, the system exhibits a period 1 motion, characterized by a period doubling bifurcation to a period 2 motion that warns about the beginning of a period doubling cascade to chaos. Two different approaches, the Fast Fourier Transform and the Harmonic Balance Technique are used to obtain approximate solutions for the period 1 and 2 motions and to predict the period doubling bifurcation by a stability analysis. The two sets of solutions match reasonably well with the numerical solution, especially for the first mentioned approach.
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  • THE SATELLITE NAVIGATION SYSTEMS – STATUS, PROBLEMS, FUTURE

    Yuriy DACHEV
    4/1/2015
    1 citation
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The satellite navigation systems are very important for the contemporary navigation, including and maritime navigation. Currently, there are several satellite navigation systems, used actively for navigation. There are several systems, which are currently being constructed. To provide the necessary coordinates and other navigation dates, they use geodetic reference systems (GRS). GRS are systems of parameters, describing the Earth as a complex geometric and physical figure. These parameters are defined based on the large amount of geodetic, astronomical, gravimetric, Doppler, geomagnetic and others measurements, related to the determination of the figure of the Earth. In world practice, including and satellite navigation systems, are used parameters of several GRS systems - of US, Russia, China, India and others. Can be mentioned that during 1979 was developed by the International Association of Geodesy and Geophysics (IUGG) international GRS system, which is recommended for application in various geodetic activities. This system is known as GRS 1980. There are some differences in the values of some of the corresponding parameters of the various GRS due to different Earth measurement databases, which are used for their determination. These parameters are continuously specified during the performing of every subsequent Earth measurement and adjusted so that GRS systems to be modified without changing of their abbreviations. There is an irreversible trend regarding getting near of values on corresponding parameters in the different GRS to the internationally accepted, moreover these differences are negligible.
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  • GIS TECHNOLOGY IN MARITIME: A MET INNOVATION AT MAAP

    Dr. Angelica M. BAYLON; VAdm Eduardo Ma R. SANTOS
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    This paper introduces MAAP, its curriculum and research and extension initiatives including but not limited to one of MAAP latest best practices in introducing GIS to its community (internal and external) who share similar passion for MET innovation. The various GIS–based accomplishments led and shared by MAAP as part of its Research and Extension Services (RES) initiatives are presented namely: several GIS-based papers presented and published both local and international; GIS-based project proposals for campus management enhancement prepared for MAAP, Bataan Peninsula State University (BPSU), Lyceum University of the Philippines ( LPU) and Catanduanes State University (CSU); capability Training on GIS for MAAP community and other interested institutions; and Commission on Higher Education (CHED) and Department of Science and Technology (DOST)- endorsed National 3-day GIS Conference are also discussed. There are 78 proposed GIS-based research project workshop outputs currently being implemented by 20 higher educational institutions (HEIs) in the Philippines, 17 of which are applicable to any maritime education and training institutions (METIs). MAAP has six on–going GIS- based special academic research and development projects which this paper intends to share to co-AMFUF members.
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  • STUDY OF A FREQUENCY CONVERTER POWERED BY SINGLE PHASE VOLTAGE DESIGNED TO CONTROL THREE-PHASE INDUCTION MOTOR

    Bohos APRAHAMIAN
    4/1/2015
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The paper presents the design and the experimental study of a prototype of frequency converter powered by single phase voltage designed to control three-phase induction motor for the needs of the Laboratory of electric drives of the Technical University - Varna. A number of tasks related to the design of the basic elements of the frequency converter as a bridge rectifier, bridge inverter and driver board are determinate and solved. A special programming of the converter is realized concerning different operating regimes of the three-phase induction motor. In addition, numerous experiments are conducted with the real-made prototype.
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  • EDUCATION REGARDING GREEN REFRIGERANTS IN C.M.U.

    Daniela-Elena MITU
    10/1/2014
    1 citation
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    From technical point of view and from environmental point of view, and also for a sustainable development of our society are needed tools which enable to analyse the effects of human activities, including maritime transport. Refrigerated transport is essential for our society due to the need to preserve and protect food or medical supplies during transportation, to the benefit of the people worldwide. But the education of future marine engineers is in closely connected to environmental protection. The paper is focused on needed to knowledge and to understanding the working principles of the marine refrigerating plans, tools which should be at hand of future marine engineers. These competences should be gained during faculty, through a discipline called “Marine Refrigerationg Plants” included in the curricula of the license program entitled “Electromechanics”, developed in C.M.U. This paper is mainly focused on the selection of refrigerants. There are some classic selection criteria: thermophysical properties, technological and economic aspects, safety and environmental factors; however, in addition to these criteria, others have to be considered: local regulations and standards and “cultural” criteria.
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  • THEORETICAL APPROACH FOR OPTIMAL DESIGN OF SHELL AND TUBE HEAT EXCHANGERS ON GENETIC ALGORITHM BASIS

    Feiza MEMET
    10/1/2014
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Heat exchangers are devices used to transfer heat between at least two fluids heaving different temperatures; in most of the situations, these fluids are separated by a solid wall. Shell and tube heat exchangers are the most common type of heat exchangers; this is why more attention on their design, optimization and analysis is absolutely needed for energy conservation in the process of heat transfer. This paper presents an approach related to optimum design of shell and tube heat exchangers. The approach relies on the genetic algorithm for optimization of this kind of devices. The genetic optimization algorithm is based on the value of an objective function. It will be assumed that the objective function is the total cost function, which should be minimized. The use of such a method in practice will leed not only to optimal geometric design features, but also to the consideration of economic aspect of these devices.
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  • SIMILARITY CRITERIA FOR SHIP MODELLING AND MAGNETIC SIGNATURE ANALYSIS

    Georgiana MARIN; Gheorghe SAMOILESCU; Octavian Baltag
    10/1/2014
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    In order to analyze the magnetic signature of a naval ship, there was employed a physical scale model of the respective vessel. The model was built to a scale of 1:100, respecting the geometric similarity criteria, in terms of main dimensions proportionality. A physical similarity criterion characteristic to the magnetic signature issue was formulated, taking into account the ratio between the hull sheet thickness and the electric and magnetic properties of the ship and the model, respectively. There have been performed a large volume of triaxial measurements of the magnetic signature, to acquire the magnetic field distribution for an horizontal plane situated below the hull, at reference depth. Based on the analysis of magnetic signature components of the model ship, some conclusions regarding their shape can be drawn.
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  • QUAY TRANSFER OPERATION ANALYSIS FOR A CONTAINER TERMINAL

    LOKE K.B.; A.H. SAHARUDDIN; M.R. OTHMAN; I. RIZAL; A.S.A.KADER; A.M.ZAMANI
    10/1/2014
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    A lot of studies focused on quay transfer operation efficiency. It emphasized on increasing the handling rate and improving the performance by mathematical, modeling or empirical study. Therefore, this study aimed to study delay factors of quay transfer operation in a container terminal, which affected the productivity performance. It tried to overcome the shortcoming of previous studies. Quay transfer operation is one of the operation systems in container terminal, which is affected by many factors and also affected other operations. The delays of the operation will slow down the handling performance and increase the handling time and cost. Hence, an extensive observation and survey activities were done in Malaysian container terminal. The data obtained from relevant respondents that involve in operation. The initial result showed that waiting for prime mover ‘often’ occurred on quay transfer operation. Delay of quay crane and prime mover break downs ‘moderately’ delay the operations. However, waiting for game plan ‘seldom’ affected the operation. Therefore, this study concluded that the handling equipment is the main cause of delay in quay transfer operation in a container terminal.
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  • CONTAINER YARD OPERATION ANALYSIS FOR A CONTAINER TERMINAL

    LOKE K.B.; A.H. SAHARUDDIN; A.R. IBRAHIM; I. RIZAL; A.S.A.KADER; A.M.ZAMANI
    10/1/2014
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    This paper studied the key delays factor of container yard for a container terminal. It explored the key delays factor that affected the operating performance of container yard operation. Hence, a survey is conducted and analyzed by SPSS. Descriptive analysis, normality test and reliability test are used to analyze and display the result. The initial result showed that rubber tyred gantry crane, turning for 90o and waiting for prime mover are often happened during the container yard operation. As a conclusion, the handling equipment is the main cause of the delays factor.
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  • LOADING OF SCRAP-METAL ON SHIP OF «COASTER» TYPE

    Vitaliy KHOMYAKOV; Victor SAVCHUK
    10/1/2014
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The article is devoted to the technology of carrying of scrap metal on coasters. Scrap metal, being the cargo, possesses characteristics, which should be taken into consideration by navigator at ship loading. The peculiarity of such category of cargo is relatively serious stowage factor. The pile of scrap metal contains various metal components and items of different shape, size and weight. The observations during the voyage have allowed the determination of the following fact: when grab tears some scrap metal off the pile, it destroys or straightens the parts of the cargo that have lain affected by the pressure forces, and while being loaded into the hold, they may change shape and size. This phenomenon is noticed, when the cargo consists of spring products, wire, tin plates and deformed sheet metal. At present to reduce the loss of the space of the hold at the loading of scrap metal the technology of its “compression” with grab, press or other devices is used. The maximum attention should be paid to the process of “compression” as very often it becomes the reason of underloading of the vessel with the scrap metal. At the designing of the coaster vessels for the future fleet the constructive characteristics of the hold are suggested to be reviewed. The possibility to install the special moving metal bulkhead should be foreseen. It will allow making this fleet more specialized and adapted for the carrying of two or more kinds of scrap metal, bulk cargo simultaneously. The ship-owners will obtain wider opportunities for the exploitation of the new fleet at different freight markets.
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  • FINITE DIFFERENCE TIME DOMAIN METHOD FOR ACOUSTIC WAVES IN ATTENUATE AND ABSORPTIVE MEDIUM FOR LAYERED UNDERWATER ACOUSTIC ENVIRONMENTS

    Jawad LAKZIZ; Sofiane OTMANE; Said OUASKIT; Rachid El GUERJOUMA
    10/1/2014
    1 citation
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    In this work, we use Finite Difference Time Domain (FDTD) method to investigate the underwater acoustic wave propagation problem; in order to understand the acoustic wave propagation properties and determining the effects of the attenuation and absorption for the sound intensity in the sea. The results are presented for calculated Transmission Loss (TL) of propagating acoustic waves in layered underwater acoustic environments by using Finite (FDTD) method. In a first step; the sea environment are modeled as one layered medium before generalizing the resolution to two layered (fluid-fluid and fluid-solid) medium. The sea surface and the sea bottom are considered to be planar surfaces. The discretized acoustic wave equations are used in the algorithm of the FDTD method and Perfectly Matched Layer absorbing boundary condition is applied to eliminate numerical reflections from the ends of the grid .Two cases are discussed (Taking account of absorption and attenuation).The good performance of this method is validated with the results of BELHOP program and by comparison with the analytical method.
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  • SPECIFICS OF CHEMICAL TANKERS FLEET AND ITS MARKET OUTLOOK

    Gunes ERGUN; Dimitar DIMITRAKIEV; Aleksandar SIRAKOV
    10/1/2014
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    This paper introduces a general outlook of the chemical tanker market and examines the performance of chartering contracts over the period 2008 to 2013. The number of the liquid chemical cargoes has increased enormously since at the early days, the tanker market was expressing only for carriage of petroleum products. As long as the number of the carriage of chemical cargoes by sea are growing up rapidly, the study aim is to clarify peculiar and main characteristics of these tankers. Although, the big part of these chemical cargoes are extremely dangerous to the environment as well as to the life of the seafarers, it may be considered as a small risk due to the very high standards required regarding safety. Apart of the technical point view, the chemical tanker market is forecasted and expected to recover and improve in/after 2014. The main evidence for this theory is that declining fleet growth, shrinking tonnage growth and increasing seaborne trade. Due to these influences, the market gives positive forecast for its short and near future. However, the chemical products market is still weaken enough and presently demand is still shaky, but due to the limited order books, it could be considered as a positive sign in medium period. Nevertheless, the fleet is still in overcapacity and expectations for improving is at the end of 2014 or later on. The purpose of this paper is to study on the present market and strive to forecast the future chemical tanker market situation
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