Items

  • ADVANTAGES AND DISADVANTAGES OF DIFFERENT TYPES OF MODERN MARINE PROPULSIONS

    Mihail – Vlad VASILESCU
    10/1/2018
    1 citation
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The main focus of this article is the development and use of different types of modern marine propulsions. The main goal is the diversity of energy sources and the reduce of environmental pollution, hoping that this will ensure future energy security supply. I propose to show the advantages and disadvantages of different marine propulsions. The main reason of this article is to try to show a modality for reducing ship pollution and the quantity of fuel used, increasing the energy efficiency, that means, to reduce the price of transportation and a method of saving money for the owners. As a result of my research I discovered that is more convenient to use nuclear propulsion comparing with other conventional types of propulsions. In recent years, a lot of money had been invested in the development and research of security measures for nuclear propulsions, but most of them for military navy of highly developed nations. Nuclear propulsion is particularly suited to ships that need to be at sea for long periods of time without refuelling. Fuel costs are initially paid together with the reactor, initially high, but over time costs are attenuated.
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  • MARINE CASUALTY ANALYSIS OF BUNKER TANKERS BETWEEN 1966 AND 2017

    Coşkan SEVGILI; Yusuf ZORBA
    10/1/2018
    6 citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Marine casualties are very critical issues for both maritime sector and the world. Due to generally large impact of marine casualties, there may be seen serious mortality, loss of property and financial, and environmental problems. The ships which are tanker type have more impact and dangerous on marine casualties because of due to the characteristics of the cargo that they carry. Bunker tankers, which are a type of tankers, are in close operation with the vessels when they serve their services. For this reason, the possibility of involved in a marine casualty of these ships is higher. In this paper, it was aimed to analyzed bunker tanker casualties, circumstances and their results. 204 bunker tanker casualty reports occuring between 1966 and 2017 were analyzed using Statistical Package for the Social Sciences (SPSS) 22.0 package. These reports were provided Information Handling Services (IHS) Markit Maritime Portal. According to analysis results, the most common types of casualties were determined as collision (32.8 %), hull and machinery damage (27.0 %) and wrecked/stranded (22.1 %), respectively. In addition, casualty involving injury or death and environmental pollution rates were found low, while almost half of the casualty reports were reported as serious.
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  • ENVIRONMENTAL IMPACT OF POLUTANTS ON SOIL AND SUBSOIL

    Mariana PANAITESCU; Fanel-Viorel PANAITESCU
    10/1/2018
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The paper present details of analysis of soil samples which were contamined in soil, in rihizosphere areas. Surface samples were collected from a depth of about 0-15 cm. Depth samples were taken from a depth of about 20-40 cm. Research and methods: soil samples were taken as „Technical Guidelines on procedures for investigation and assessment of soil and subsoil” issued in accordance with GD. 1408/2007 and Ord. 184/1997. The sample is soil under the influence of soil heavy traffic recreation area, near the intersection Mangalia – Saturn. The indicators which were analysed are:lead, nickel, copper, total chromium, zinc. For each indicator, were analysed, from April to October month, the quantities (in mg/d. s), for 3 types of usage:normal, alert threshold, intervention threshold, for Mangalia - Saturn – Area and for Mangalia - Saturn – Depth. Results: risk matrix and calculations of test solutions. Conclusions: The trend is the accumulation Ni and Cr in all indicators have not exceeded the normal values. Indicators Cu and Zn values determined in generel ranks around the normal, with few exceptions below alert threshol..
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  • R SCRIPTING LIBRARIES FOR COMPARATIVE ANALYSIS OF THE CORRELATION METHODS TO IDENTIFY FACTORS AFFECTING MARIANA TRENCH FORMATION

    Polina LEMENKOVA
    10/1/2018
    44 citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Mariana trench is the deepest place on the Earth. It crosses four tectonic plates of the Pacific Ocean: Mariana, Caroline, Pacific and Philippine. The formation of the trench is caused by the complex interconnection of various environmental factors. The aim of this study was to describe and characterize various impact factors affecting formation of the Mariana trench geomorphology and continental margin environments using R programming language and mathematical algorithms of correlation methods written on R code. To record the system of geological, tectonic, geographic, oceanological and bathymetric features affecting Mariana trench, a combination of statistical methods, GIS and R programming codes were applied. The questions answered are as follows: which factors are the most influencing for the Mariana trench morphology, and to what extend do they affect its development? Is sedimental thickness of the ocean trench basement more important factors for the trench formation comparing to the steepness slope angle and aspect degree? Three methods of computing were tested: Pearson correlation, Spearman correlation, Kendall correlation, numerical correlogram, correlation matrix and cross-correlatios to analyze environmental impact factors. The correlogram matrices are computed and visualized by R scripting libraries. Complex usage of programming tools, mathematical statistics and geospatial analysis enabled to get a differentiated understandings of the hadal environments of the Mariana trench. The results revealed following three types of factors having the highest score: geometric (tg° slope angle), geologic (sedimental thickness) and tectonic structure. The results furthermore indicated that tectonic plates, sedimental thickness of the trench basement and igneous volcanic areas causing earthquakes play the most essential role in the geomorphology of the trench.
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  • ISSUES IN THE HANDLING OF A MULTI-MASTED SAILING VESSEL IN VARIOUS HYDRO-METEOROLOGICAL CONDITIONS

    Yuriy DACHEV; Ivo LAZAROV
    10/1/2018
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Navigation under sail has been known to people for at least a thousand years, having evolved with the advance of mankind, where the quest has always been towards shortening sailing time by optimal routing and pursuing top speed. With the development of computer technologies and automation in shipping, the art of conning a sailing craft has been transformed and enhanced to a new level. Great consideration is now given to the protection of the marine environment and the atmosphere from the ever-increasing carbon emissions, which has resulted in the rediscovery of wind-powered navigation. It is worth noting that the global demand for and purchases of medium and large sailing boats and motor yachts with sails have plummeted over the last 10 - 15 years. The effect of wind and seas on sailing ships operation is disproportionately greater compared to motor-driven vessels. For the purposes of safe navigation sailing crews must closely observe the parameters of sailing vessels’ movement, hydro-meteorological conditions and navigational aids’ operation. They provide essential information of the ship's position, course, heel angle and rudder angle, distance made good, the elements of the hydro-meteorological conditions as well as forthcoming weather forecast, etc. Present-day sailing relies on these parameters for the normal operation of the various automatic systems used in the handling of sailing vessels. A universal automatic system has not yet been developed that would incorporate all factors at play in the safety of sailing in such a dynamic environment. The modelling of such a system will ensure the safe and optimal movement of multi-masted sailing vessels, regardless of the hydro-meteorological conditions in the navigation area.
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  • SWOT ANALYSIS OF THE PHILIPPINE MANNING

    Prof. PhD. Angelica M BAYLON, Ph.D.; VAdm Eduardo Ma R SANTOS, AFP (Ret)
    10/1/2018
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The Manning industry known as the recruiter and selector of Filipino seafarers to foreign ship-owners for the purpose of manning their oceangoing commercial vessels is on the crossroads in ensuring that the Philippines known as the manning capital of the world would sustain the market leadership of the Philippines in the global ship-crewing industry by constructively addressing a complex of internal issues that threaten competitiveness. While such is a perfectly legitimate aspiration, the larger goal must equally pay attention to the enormous pressures imposed by the external environment, mainly the matter of competition and non-traditional opportunities which emerge within the manning sector, including its direct links with the global maritime industry in which it thrives. The seafarers, predominantly men in the deck and engine positions but joined by a significant number of women in cruise ships, are deployed through the manning companies which select, hire and train them by virtue of contracts with the overseas operators or owners. Filipino seafarers are widely acknowledged by foreign ship-owners, called principals, for their ability to sail and operate merchant ships of all types with efficiency, safety, and general cost-effectiveness. This paper presents an analysis of the strengths, weaknesses, opportunities, and threats that are facing the Philippine Manning Industry for the year 2014-2015.
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  • CONCEPTUAL MODEL FOR EVALUATION OF SHORT SEA SHIPPING ENVIRONMENTAL PERFORMANCE

    Aneta VARBANOVA
    4/1/2018
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The present paper analyses the environmental performance of short sea shipping in terms of greenhouse gas emissions and its impact on the strategic development of shipping companies. The legal framework and policy issues at EU and international level are studied. A framework of parameters is developed for analysis of energy efficiency and CO2 efficiency of short sea shipping. A conceptual model is proposed for evaluation of the environmental performance of short sea shipping based on а developed system of performance indicators. The proposed conceptual model serves as a basis for quantification of the environmental impact of shipping activities of the company and strategic decision-making as concerns investment in technologies, new-buildings and services restructuring for enhancement of environmental performance.
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  • EFFICIENT DESIGN OF THE GEAR UNIT WITH A ONE-SPEED GREARBOX WITH COMPUTER PROGRAM

    Mihaela TUROF
    4/1/2018
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    By introducing international standards and local rules and Normalization was a lavish a production version based machines Field organs, thus creating interchangeability -the opportunity Machines bodies, with huge implications for maintenance and machine reliability. Technological evolution implies a great flexibility of production capabilities with strong influences on changing design concepts. The emergence of personal computers is also favored by a tendency to globalize design rules through specialized design programs. The overall picture of design processes is changing very quickly and is determined by the emergence of modern means that designers have at their disposal today. Computer problem solving has been a strong motivation, so that later hardware development and PC development have led to the emergence of software dedicated to mathematical problems. For over 20 years, Mathcad is the recognized standard in designing, documenting and collaborating with computers, calculation methods and algorithms in design. This paper proposes the design of the gear unit for a single speed gear using the mathcad program.
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  • ENERGY EFFICIENCY DESIGN INDEX ASSESSMENT FOR INLAND OIL TANKER OF BANGLADESH

    Sohanur RAHMAN
    4/1/2018
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Energy Efficiency Design Index (EEDI) was introduced since 2013 for new ships as a measure to improve energy efficiency of sea going ships. This factor already has created a great influence on global maritime industry. However, any requirement related to the energy efficiency of inland vessels does not exist. This paper attempts to evaluate EEDI for inland oil tankers of Bangladesh. According to the results of this analysis, which has been based on 90 existing inland oil tankers, EEDI that was introduced for seagoing ships cannot be applied B for proper evaluation of inland oil tankers due to limitation of carrying capacity and installed main engine power. So, the main objective of this paper is to provide EEDI reference line for inland oil tankers of Bangladesh.
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  • THE SIMULATION OF WASTE WATER TREATMENT PROCESSES

    Mariana PANAITESCU; Fanel-Viore PANAITESCU; Iulia-Alina ANTON; Andrei-Alexandru SCUPI
    4/1/2018
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Simulation of processes in a wastewater treatment plant is very effective because it reduces operational times, reduces costs for the preparation of uninitiated human resources in the field and also reduces utilities consumption. This can be done using many specialized programs. The purpose of this work is to present such a simulation using the GPS program-X-Hydromantis.
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  • REVIEWING STUDIES ON PORT SECURITY: WHAT HAS BEEN DONE?

    Nurduhan MUAMMER; Kuleyin BARIŞ
    4/1/2018
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    This paper aims to analyze and evaluate studies on port security, which is an increasing concern, and summarize them to put them in order. It was obviously seen with the 9/11 terrorist attacks that terrorists also have suicide capabilities to maritime targets. Consequently, International Ship and Port Security (ISPS) Code came into force by International Maritime Organization (IMO) in 2004. In this paper, port security, as one of the main subjects of ISPS Code with the ship security, is analyzed. Therefore, Dokuz Eylul University Online Library is searched with some constraints which includes “port+security” in title and all articles should have “full text” and “academic journals” status. Searching was completed with 145 articles and 58 of them were analyzed. Articles were categorized under such four different subtitles as “importance of security”, “economic, financial and legal dimensions of security”, “security threatening elements”, and “technological advances in security”. It can be said that studies on port security mainly focused on the ISPS Code. However, the great majority of the studies have been addressed to port security and the ISPS Code in the same manner. In order to ensure port security, it is necessary to concentrate on those studies that will centre on different aspects of port security.
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  • A POINT OF VIEW ON PREREQUISITES IN THERMODYNAMICS FOR FUTURE MARINE ENGINEERS

    Elena GOGU
    4/1/2018
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    A career on board the ships as engineers is an interesting option for young people graduating high schools in Constanta county and not only. Thermodynamics plays a vital role in the academic life of future marine engineers. This is why physics professors and Thermodynamic lecturers from “Gheorghe Duca” Technological High School and Constanta Maritime University decided to test the level of retention of perquisites in Thermodynamics, with focus on internal combustion engines (ICE). A group of 30students from “Gheorghe Duca” Technological High School have been tested in order to quantify the gained knowledge on ICE. They have been selected from the last year of study, they being interested in maritime jobs. The testing was based on a questionnaire containing theoretical and calculus aspects. The time of solving was established at 50 minutes. The results showed that our future graduates (and potential future maritime professionals) proved a good knowledge retention. Also the analysis of the questionnaire results is able to provide to the CMU lecturer a profile of its potential students. In the same time, he can improve his activities during classes, in order to achieve the right level of knowledge requirement.
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  • SUDIES CONCERNING FLORA FROM DIFFERENT PROTECTED AREAS IN CONSTANTA COUNTY BY APPLYING ECOLOGICAL AND STATISTICAL METHODS

    Simona GHIȚĂ; Mihaela HNATIUC
    4/1/2018
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    This study presents our results concerning the geographical distribution, ecological and anthropic impact aspects of the wild flora from three protected areas (Fantanița Murfatlar, Gura Dobrogei and Hagieni forest). All three nature reserves studied belong to the Natura 2000 European network protection. From this point of view we watched the current state and future premises on the maintenance of vulnerable species / endangered in the natural habitats. The study is based on monitoring for 3 years (January 2015-December 2017), in which we identified: main plant families, distribution of species in geoelements and analysis of ecological categories (moisture factors, temperature and soil reaction). For a better tracking of the similarities between species in three distinct areas, we used the statistical method of processing data. The results showing important similarities between the three types of protected areas with respect to the balance of positive and negative effects using Pearce coefficient and respectively with respect to structure and function of natural biota.
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  • SUPPRESSING CHAOS IN POPULATION DYNAMICS DISCRETE MODELS BY ADDING PERIODIC PULSES TO THE SYSTEM VARIABLES

    Deleanu DUMITRU
    4/1/2018
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The inability to predict the evolution of population dynamics in the presence of chaos can lead to catastrophic situations so chaos-control techniques must be applied to direct the system towards a predictable behaviour. This can be done either by controlling chaos, so the system’s final state is an unstable periodic orbit embedded in the strange attractor of the original system, or by suppressing chaos and producing a controlled regular state of an auxiliary system. A simple and efficient algorithm that suppress chaos by adding constant and periodic pulses to the dynamic system variables has been proposed by Guemez and Mathias. The pulses are introduced into the system either in multiplicative or additive ways. The performance of the method depends critically on the period and the strength of the feedback. With the aim of proving the merits of the method and providing multiple numerical evidences concerning the ability of the approach to change the chaotic state into a periodic one, in the paper we analysed a discrete-time two species food chain model having a rich spectrum of dynamical behaviours including chaos. Because the system parameters were chosen so the system behaves chaotic but close enough to a period-6 window in the bifurcation diagram, we concentrated mainly in stabilizing orbits having periods multiple of six. However, other cases were also considered. The influence of feedback strengths on the stabilization process was highlighted by computing and drawing colour maps presenting the period of the stabilized orbits. They show that even small interventions on system variables can direct the system to the desired goal.
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  • ANALYSIS OF RIVER LEVEL AND OF THE VOLUME FLOW ON THE DANUBE CLOSE TO THE CITY OF TULCEA, BASED ON IN SITU MEASUREMENTS

    Alexandru BANESCU; Lucian Puiu GEORGESCU; Catalina ITICESCU; Eugen RUSU
    4/1/2018
    33 citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    This work presents a review of hydrological data known as water levels and volume flows that have been recorded and then processed to render a contour about the hydrological situation of the Danube River near Tulcea. Onsite measurements have generated daily data on river flows and levels over a 3-year period (2003, 2004, 2006), their interpretation being important for knowing the water drainage regime. Moreover, the characteristic values can have a practical interest in some river design works, such as hydrotechnical flood defense constructions that may occur as a result of elevated levels above a certain threshold or may be beneficial during works or exploitation of river bed resources. In order to accurately present the importance of knowing the river level variation, it is necessary to process, verify and interpret all data on the levels and flows, establish links and graphical correlations, and determine the characteristic values over the multiannual period. The results obtained from the measurements are described in the four periods of the year, and the conclusion shows that each period is manifested both in climatic and hydrological terms by specific characteristics and phenomena.
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  • EVALUATING THE IMPACT OF MARPOL SULFUR EMISSIONS CONTROL REGULATIONS ON EUROPEAN SHORT SEA SHIPPING

    Aneta VARBANOVA
    10/1/2017
    6 citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Short sea shipping industry of the European Union is a vital part of the European transportation networks. The present article analyses the recent trends in the development of European short sea shipping (SSS) and the economic impact of Annex VI of Marpol Convention regarding regulations on sulphur emission control. The IMO and the EU regulations related to sulphur emissions control have been studied in detail to outline the main issues concerning the feasibility of regulations compliance. The results from the empirical data analyses have shown that European SSS shipowners and operators have several alternatives in order to abide by these regulations. Compliance with regulations leads to higher operating costs that impede the competitiveness and further development of the industry.
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  • DESIGNING THE SCREW-NUT ASSEMBLY ON A COMPUTER-AIDED RATCHET PRESS

    Mihaela TUROF
    10/1/2017
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    By introducing the Mathcad software in design of machine is made interactive and easier data processing. In application created can be modified easily input data to obtain more rapid project results. The main source of AutoCAD is the ability to develop specialized applications running in the same graphical environment. The market for software developers under AutoCAD environment is immense. Basically, any care theme involves designing and finding somewhere more or less elaborate. This paper proposes the design of the screw-nut assembly to a ratchet press with Mathcad and AutoCAD software.
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  • ONE APPROACH FOR INTEGRATION AND VISUALIZATION OF MARINE AND AIR TRAFFIC DATA IN COMMON GIS

    Miroslav TSVETKOV
    10/1/2017
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    This paper represents a study on the possibilities for integration marine and air traffic data into a common geographic information system (GIS) display in the interest of better monitoring and management of transborder transport corridors. The maritime automatic identification system (AIS) technology, the automated reporting system for aviation transport (Automatic dependent surveillance – Broadcast, ADS-B) technology and the corresponded data transmition protocols are presented and analysed.
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  • ONE WAY TO PROTECT THE INFORMATION OF THE SHIP'S SENSORY NETWORK FROM EXTERNAL INTERFERENCE AND CYBER ATTACKS

    Miroslav TSVETKOV
    10/1/2017
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    This paper represents a study for information security of ship’s navigational sensory network and possibilities for protection of the data streams on it. The current state and future evolution of basic protocols and standards for communication between marine electronic devices are described. It is found, that the data on the ship's sensory network is not protected from cyber-attacks and external interference. An approach is proposed for securing the ship's sensory network using micro-crypto devices for encryption of the navigational data between different sensors, indicators and systems. Every micro-crypto device is consisting of programmable microcontroller, which uses symmetric-key algorithms for encryption/decryption of the data with 128 bits key size. In addition, every micro-crypto device has a unique identification number (ID) and they are programmed to communicate with exactly defined sensors, indicators or systems in the network. The proposed solution falls under the domain of technical information protection measures. The implementation and the use of the proposed cybersecurity solution and increasing of the level of protection of marine navigation information will significantly enhance the safety of navigation and, respectively, the safety of human life at sea.
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  • USING A NAVIGATION SIMULATOR IN THE DEVELOPMENT OF A COLREGS ECOURSE

    Sivkov YORDAN
    10/1/2017
    8 citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Acquisition of skills to apply the International Regulations for Preventing Collisions at Sea (COLREGs) is one of the basic abilities of students from the Navigation specialty. Further training is a global requirement as well as self-improvement of students worldwide. Training institutions have no opportunity to do so; moreover, the creation of new centers would require a large financial resource, which necessitates flexible approaches to the training while taking into consideration the current situation. The build-up of electronic resources in the environment of the global network for a complementary or further training with assessment of performance is entirely in the spirit of modern standards for providing relevant training. Application of navigation simulators is a new approach to creating training content for the electronic courses. It has a gradual transition between university education and the need for additional COLREG training. One of the main advantages of using simulations is the different angles in which a given situation is presented and the possibilities for re-pass. The comparison of what is visually observed from the bridge and the radar screen with a "bird eye-view" gives learners additional skills to read real situations in their practice.
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  • AN EVALUATION OF THE ENERGY EFFICIENCY DESIGN INDEX BASELINE FOR PASSENGER VESSELS OF BANGLADESH

    Sohanur RAHMAN
    10/1/2017
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Energy Efficiency Design Index (EEDI) was introduced since 2013 for new ships as a measure to improve energy efficiency of sea going ships. This factor already has created a great influence on global maritime industry. However, any requirement related to the energy efficiency of inland vessels does not exist. This paper attempts to evaluate EEDI for inland passenger vessels of Bangladesh. According to the results of this analysis, which has been based on 90 existing inland passenger vessels, EEDI that was introduced for seagoing ships cannot be applied for proper evaluation of inland passenger vessels due to limitation of carrying capacity and installed main engine power. So, the main objective of this paper is to provide EEDI reference line for inland passenger vessels of Bangladesh.
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  • HOW TO APPROCH THE OTTO CYCLE THEORY DURING THE UNDERGRADUATE THERMODYNAMICS COURSE IN CMU

    Feiza MEMET
    10/1/2017
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The approach presented in this paper refers to the study of the effect of specific heat of working fluid and heat loss on the performance of an Otto cycle, using finite time thermodynamics- as a powerful thermodynamic tool in the hand of specialists. Traditionally, Otto cycle performance issue was presented to the students in the case of constant specific heat, available only if it is assumed that the working fluid behaves as a perfect gas, meaning for relatively small temperature differences. Since in the practice are met large temperature differences, should be considered the case of variable specific heat, in this paper the adiabatic exponent being taken as a liniar function of temperature. For the both situations discussed in the paper are given formula for the calculation of the total energy of the fuel, the heat added to the working fluid, the heat leakage, the compression and expansion efficiencies, the work output and the thermal efficiency. The calculus is based on the cycle shown in temperature- entropy diagram, in which are also indicated the irreversible adiabatic compression and expansion.
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  • INCREASING THE FRETTING AND FATIGUE RESISTANCE OF Ti-6Al-4V THROUGH PLASMA PROCESSING IN NONAUTONOMOUS PLASMA GLOW

    Momchil MANOV
    10/1/2017
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    Titanium alloys possess unique combination of good mechanical properties and excellent corrosion resistance which make them an attractive material for application in marine engineering. Along with these properties there are some disadvantages. The most important of them is the low hardness and poor tribological properties, which leads to poor fretting and fatigue resistance. These drawbacks limit the application of titanium alloys in production of machine parts, which are subjected to friction and surface contact loads. They can be successfully eliminated using numerous of surface treatment methods. One of the most commonly used is plasma treatment processes in nonautonomous plasma glow. These methods usually include plasma thermochemical treatment and afterwards plasma spraying of large variety of materials to the surface of the treated sample, which will eliminate the drawbacks of the titanium alloys and will increase the area of their application in marine engineering. This article presents investigation of the results obtained from plasma nitriding and plasma spraying of titanium alloy Ti-6Al-4V in nonautonomous plasma glow using TiO2 powder. The quality assessment and morphology of the plasma sprayed layer is made using micro structural analysis, EDS analysis, XRD analysis, SEM analysis and microhardness measurements.
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  • ENERGY EFFICIENCY IMPROVEMENT OF SHIPS BY APPLICATION OF ALTERNATIVE FUELS

    Elena KATELIEVA; Hristo A. MILUSHEV
    10/1/2017
    No citations
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The purpose of this paper is to show opportunities for improvement of ship energy efficiency and reduction of Greenhouse Gas Emissions through the implementation of an alternative fuels and energy sources. Biofuel and LNG as a fuel in shipping have great potential for the future. The use of alternative fuels in maritime transport is not only a good solution for environmental protection but also provides low fuel consumption and reduction of operational costs. Biofuels contain no sulphur and reduce carbon emissions. LNG is high-energy fuel with lower carbon content. These energy sources are suitable alternative and an environmentally friendly solution for replacing fossil fuels in the transport sector. Please use first-name for correspondence.
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  • REPAIRING WORN-OUT RUDDER BEARING HUB AND PROPELLER BY MEANS OF BUILT UP WELDING

    Hristo HRISTOV
    10/1/2017
    Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced; technologies for MET; Climate changes
    The proposed article describes the process of repairing worn-out rudder bearing hub by means of built up welding by the electrode subfusion welding method, as well as, the repair of propeller blades by semi-automatic MIG welding. The technological sequence of the recovery process is described, the used consumables are listed, as well as the technological modes of welding. The main steps of the process are illustrated.
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