Items · Journal of Marine Technology and Environment

ANALYSIS OF THE CRACK LENGTH AND TEMPERATURE OF A CANNON BARREL USING THE J INTEGRAL

Ioan CALIMANESCU; Liviu-Constantin STAN

10/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

Perhaps the most accurate and elegant method for computing the energy release rate is to calculated the J integral by converting the line integral into a domain integral which can easily be calculated using the known finite element shape functions. The problem illustrates the case of a crack in a cannon barrel, together with the relevant geometry against crack length defined from the bore of the cannon. This crack geometry is the most dangerous integrity case for the cannon barrel. In this research, 155 mm cannon barrel with one crack with lengths of 4 mm, 8 mm and 12 mm on inner surface is firstly structurally analyzed at room temperature, and subsequently coupled thermo-structurally analyzed considering 4 scenarios, where the crack length was deemed to be 4 mm, the temperature of the inner surface was 1000C, 1250C, 1500C, 2000C. The numeric model presented in this paper, provides consistent and reasonable results for the dependency of stress intensity factor to the crack length and temperature of a cannon barrel using the J integral. The temperature fields inside the cannon barrel (and, generalizing, inside any circular structure with thick walls) tends to ameliorate the stress fields existing on the crack tip and pushing the calculated KI downward and thus improving the crack behavior.

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OPTIMIZATION OF A METAL MATRIX COMPOSITE HYPERSONIC MISSILE AERODYNAMIC SHAPE AND STRUCTURE BASED ON THE ADVANCED TECHNIQUES

Ioan CALIMANESCU; Liviu-Constantin STAN

10/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

Applied aerodynamics has, historically, involved a very strong mix of theory and experiment. This is partly because experiments can be very costly and computations are rarely sufficiently sophisticated. This will continue to be the case. Computational Fluid Dynamics (CFD) is playing an ever increasing role in aerodynamic design for advanced missiles either for performance improvement of the existing system for new missions or for new concept development for future missions. A cost effective design process is to judiciously combine the wind tunnel tests and CFD studies that exploit the inherent strengths of each of these. Hypersonic missile flight is characterized by a high flight Mach number (usually greater than 5), thin shock layers and high viscous loads. The missile aerodynamic geometry has high impact on different missile systems such as control, propulsion, structure, and warhead. The objective of the current paper is to present a reliable Finite Element Analysis/CFD and Fluid Structure Interaction (FSI) advanced technique for obtaining hypersonic missile aerodynamics and use this technique for finding optimal hypersonic missile shape based on best structural behavior (the lowest von Mises stress will play the role of Objective Variable), and, secondly, based on the best aerodynamic behavior (the highest V∞ fluid velocity will play the role of Objective Variable).

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RADAR IMAGE DESCRIPTION USING TIME SERIES AND HIGH ORDER SPECTRAL MOMENTS APPROACH

Doynov BOZHIDAR; Popov ZACHARY; Alexavdrov CHAVDAR

10/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

This paper describes an attempt for modeling and estimation of a target under radar observation. High order spectral moments and time series are applied. Experiment with real target is conducted and autoregressive model is used to describe the target.

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MODELING AND ANALYSIS OF A RECONSTRUCTION OF SHIP SEARCHLIGHT USING LED MATRIX

Bohos APRAHAMIAN ; Borislav DIMITROV ; Lyubomir DANKOV

10/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The searchlights of the ships and the lifeboats are designed to help in the rapid identification of people fallen overboard and to communicate with other ships and shore. To safely perform these functions, they need to be powered from independent sources, and their capacity is determined by SOLAS (International Convention for the Safety of Life at Sea), according to the required duration of illumination. Although light communication is shifting from various forms of radio communication, it is still indispensable element of navigation equipment of each vessel. New LED light sources provide high brightness, high efficiency (the ratio of light to electricity usage) and responsiveness (the transition from off in a state of maximum brightness). This allows for the construction of relatively small-sized searchlights with multiple parameters exceeding the requirements of SOLAS.

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THE ENVIRONMENTAL IMPACTS OF EMMISIONS GENERATED BY ROUTINE OPERATION ON PORTS

ABDUL CHALID; ABD SAMAN BIN AB KADER; AHMAD KHAIRI BIN ABD WAHAB; MUHAMAD HANIS

10/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The expansion of international trade arising from globalization has led to a substantial increase in goods transshipment between ports. This has led to increased emissions from ships in ports, and trucks traveling to and from ports. Increment of ship traffics and machineries could be a source of gaseous emissions and particulate pollutants. This study attempt to investigate the problems in Johor Port. Emission sources concentration of sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon oxides (CO, CO2) and particulate matter less than 10 µm (PM10) in port were obtained. From the results obtained based on the comparison with Recommended Malaysian Air Quality Guidelines (RMAQG), NO2 concentration surprisingly exceed the limit by 5.9 percent in sampling station 2 while highest SO2 concentration were detected in sampling station 1 and 3 with a value of 0.2 ppm exceeding the RMAQG limits of 0.13 ppm by 53.8 percent for both stations. Other gaseous at station 1, 2 and 3 are still within the recommended guidelines. Based on the computation of Ocean-Going Vessels (OGVs) emissions estimate and later compiled as inventory, the results clearly shows that major pollutants contributor in Johor Port are oxides of nitrogen (NOx) and sulphur dioxide (SO2) with a percentage value of 60 and 27 percent for maneuvering mode while 60 and 28 percent for berthing mode. Other pollutants contribute below than 10 percent for both modes.

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CORROSION BEHAVIOR OF ALUMINIUM ALLOY IN SEAWATER AT TWO DIFFERENT SITES OF KUALA TERENGGANU COASTAL AREA

WAN NIK W.B.; AFANDA G. I; ZULKIFLI F.

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

An investigation on the corrosion behavior of aluminum at different sites of sea water in Kuala Terengganu was investigated. The method of corrosion assessment was by the use of potentiodynamic polarization scan (PP) and weight loss test. Aluminum alloy 1508 was employed in this study. This metal was immersed in seawater at different sites of Kuala Terengganu coastal area with different distance from the shore. Results obtained from electrochemical test techniques shown that lower corrosion effect of the metal significantly reduced the corrosion densities (icorr) and corrosion rate. The solution of seawater affects the corrosion rate according to their chemical and physical behavior of the sea water parameter

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RECREATIONAL BOAT LICENSING, LACK OF UNIFORMITY IN THE EUROPEAN UNION

Gavilán Jordi TORRALBO; Sanabra Marcel·la CASTELLS

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

Many European countries require the skipper of a pleasure craft to be able to provide evidence of his competence. The pleasure craft operator card or boating license permits people operate a pleasure craft. One of the requirements of this license is intended to decrease the number of boat accidents. This paper analysis the regulation of different European Union countries related on recreational boat licensing and states that there is no uniformity at European level in terms of the requirements for sailing in pleasure boats. Thus, licenses that allow navigation in pleasure boats, the theoretical and practical as well as the requirements for obtaining the qualification and training of future skipper, essential for ensuring the safety of these boats are different depending on the member state of the European Union that we are talking about. The paper is divided into following sections: Section 1 describes a brief introduction; Section 2 provides the state of art and current Spanish regulation; Section 3 analysis different European countries regulation; Section 4 proposes the need of an European certificate and finally, Section 5 remarks some conclusions and further research.

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NON-ISOTHERMAL MODEL OF LINEAR RESISTANCE IN PIPELINES PART IІ. EXPERIMENT

Tomov PEICHO; Gyurova LYUBA

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The article presents and discusses results obtained from an experimental examination of the general and linear resistances of a pipeline. The impact of the fluid temperature over the friction losses is examined. Satisfactory similarity is encountered by comparing numerical and experimental results. The possibility of head losses optimization by means of temperature change is confirmed.

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NON-ISOTHERMAL MODEL OF LINEAR RESISTANCE IN PIPELINES PART I. THEORETICAL RESEARCH

TOMOV Peicho ; GYUROVA Lyuba

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The article presents and discusses results obtained from a non-isothermal research and modeling of hydraulic linear pipeline resistance. Main objective of the work is to determine the linear resistance coefficients for pipelines of circular cross-section. The effect of the temperature variation is taken into account by the change in the viscosity value of the working fluid (hydraulic oil). The issue of thermal optimization of the flow regime is discussed as a way to reduce the head losses in the pipeline.

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MARITIME EDUCATION AND TRAINING QUALITY (METQUAL); AN APPLICATION ON DOKUZ EYLUL UNIVERSITY MARITIME FACULTY

Nas SELCUK; KoseoğLu BURAK

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The concept of quality and satisfaction related to education services have been discussed enthusiastically in last 30 years. Nowadays, almost all societies and organizations have established their own ISO 9001 – 2000 quality system with a certain accreditation association. Quality standards in maritime education have been exposed with International Convention of STCW 78/95. In quality systems to improve services and expand activities feedbacks and user’s satisfaction should be taken from users of these services. Dokuz Eylul University Maritime Faculty is taking many feedbacks from graduated students. The first version of the instrument used in this paper was developed and adopted from education service quality instrument by NAS (2000). The last version of the instrument, called as “METQUAL”, was developed considering MET needs and “Accreditation Board for Engineering and Technology”. The validity and reliability of “METQUAL” was found satisfying in the pilot studies. In this study, the quality of the education and training service in Maritime Faculty (MF) of Dokuz Eylul University (DEU), Marine Transportation Engineering Department (MTED) is evaluated with the instrument of “Maritime Education and Training Quality” by the graduates from between 1999-2008. At the end of research, the results of faculty’s service quality are presented according to graduates perception of service quality and the activities are explained, which should be done to develop and improve service quality of the faculty.

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SIMULATION OF COMBUSTION PROCESS OF A DIESEL ENGINE FUELLED WITH BIOFUELS

Adrian SABAU; Mihaela BARHALESCU; Constantin DUMITRACHE

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

A thermodinamic model has been used to investigate the combustion performance of a four cylinder direct injection diesel engine fueled by biofuels The numerical simulation was performed at constant speed. The indicated pressure, temperature diagrams are plotted and compared for different fuels. The emissions of soot and nitrous oxide are computed with phenomenological models. The experimental work was also carried out with biodiesel diesel blends, to validate simulation results with experimental results, and observed that the present model is successful in predicting the engine performance with biofuels.

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FUZZY LOGIC METHODS USED IN MARITIME CONTAINER TERMINALS

Gabriel RAICU; Alexandra RAICU

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The goal of this paper is to present the results in the development of a methodology to integrate simulation, forecasting and planning to support day by day and long term decisions for operators working in intermodal container terminals. Congestion and increasing cargo dwell times is a common scene in many of the world’s ports. Government authorities such as customs and health may delay containers from reaching their destinations due to inspections. Shipping lines are unconcerned if there is a poor terminal productivity, as long as their vessel sails on time.

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THE ADVANTAGES OF THE COMPOSITE MATERIALS USED IN SHIPBUILDING AND MARINE STRUCTURE

Alexandra RAICU

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

This paper presents the advantages of using the composite materials in shipbuilding and marine structure. The volume and number of applications of composite materials have grown steadily, penetrating and conquering also the marine industry. Modern composite materials constitute a significant proportion of the engineered materials market ranging from everyday products to sophisticated applications.

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THE INFLUENCE OF TUNGSTEN INERT GAS WELDING CURRENT ON MECHANICAL PROPERTIES OF AA5083 JOINTS

MOHD NOOR C.W.; SAMO K.B.; MUSA M.A

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The aluminium and its alloys are widely used in marine applications such as ship hull and its components due to its lightweight and corrosion resistance. The aluminium alloys require special tool and skill to weld due to high thermal conductivity. A research vessel “RV Discovery” is currently being constructed exclusively using 5083-aluminium alloy for University Malaysia Terengganu and the welding properties were investigated. The aluminium welded joint specimens were prepared using the Tungsten Inert Gas (TIG) welding process by certified welders at different current settings. The mechanical characteristics of the welded alloys were carried out for tensile, impact and hardness tests. Further, metallographic examination was conducted to identify and observe the various fusion zones. The results of these tests are presented in this paper. This study revealed that, the different welding current settings in which specimens were prepared remarkably affect the mechanical properties of 5083-aluminium alloy joints.

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THE IMPACT OF THE GLOBAL CRISIS ON THE MARITIME TRANSPORT IN UE

Cristina-Steliana MIHAILOVICI

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

That through a period of global economic crisis is a topic on the agenda, but we have to analyze what impact it has on shipping and what measures we take to maintain or why not develop maritime activity in this period. The structural changes that occur in international trade and maritime development have a direct impact on growth and expansion port.

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A FIRST AND SECOND LAW ANALYSIS DEVELOPED ON A TWO STAGE VAPOR COMPRESSION REFRIGERATION SYSTEM

Feiza MEMET

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The Coefficient of Performance is a standard criteria for performance analysis of refrigeration cycle. Even if the first law analysis method is widely used to evaluate thermodynamic systems, it deals only with energy conservation. Instead, exergy analysis offers useful indications when the performance improvement is aimed. In this paper it is developed a first and second law analysis. It is studied the influence of different parameters on the Coeficient of Performance and on the exergy efficiency of a two stage vapor compression refrigeration cycle working with ammonia frequently used in fishing industry.

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ASPECTS REGARDING SHIP MAGNETISM GENERATED BY CORROSION CURRENTS AND STRAY FIELDS

Georgiana MARIN; Gheorghe SAMOILESCU

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

In order to determine the ship’s vulnerability to magnetic detection all sources generating static and alternative magnetic fields must be considered. Besides ship ferromagnetism and induced eddy currents, major sources of magnetic signatures are corrosion related magnetism - giving both static and variable magnetic fields through various mechanisms, and the stray fiels generated by electric circuits onboard. This paper discusses the last two sources, their characteristics, the various processes of generating magnetic fields and the particular methods of reducing the resulting signatures.

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THE DEAD STATE CHOICE IN EXERGY CALCULATIONS FOR MARINE AND NAVAL APPLICATIONS

LEO TERESA J.; Emilio NAVARRO; Miguel A. RASO; Jose M. RODRIGUEZCORTIJO; Juan M. COBO

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

In this work the double choice for the dead state in exergy calculations is considered. Energy systems for marine and naval applications cover a wide range of possibilities and the exergetic analysis have proven to be a very useful tool at the previous design stages. Exergetic efficiency calculations of power generating systems allocated on board require a dead state definition as well as the knowledge of ambient conditions at any location defined by latitude and longitude. Temperature, pressure and relative humidity values at sea level all over the world have been estimated by using EdGMC software. Total exergy of ambient air and a methanol/water liquid mixture has been calculated at every latitude and longitude by using a unique dead state and a local dead state. The results obtained with both dead states are compared.

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MEASURES FOR IMPROVEMENT OF ENERGY EFFICIENCY OF SHIPS

Elena KATELIEVA

4/1/2012

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 a vast range of potential areas for energy efficiency improvement and examine different technologies and possibilities for reduction of energy consumption in ships. A combination of energy efficiency measures is considered as an integrated solution for achieving effective ship operation.

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GREEN SHIP-THE FUTURE CONCEPT OF MARITIME TRANSPORT

Voicu-Nicolae GROSAN; Codruț MUNTEAN

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

At the beginning of the 20th Century, as humanity entered the age of industrialism there was not a soul asking the question what the effects on the environment would be. However, the negative impacts that have gripped the entire planet are now undisputable, although at that time, because the human activity was negligible so was its impact. This paper focuses on how maritime transport acts as a pollution source, and what can be done to reduce the quantities of pollutants, looking both at the existing technologies and at latest research programs. The Green Ship idea refers to ideal ships that are environment friendly. We will detail this looking from two points of view: The first one is the Green Ship being a vessel that uses alternative means of propulsion, where the internal combustion engine is replaced with electrical engines that use sun charged voltaic batteries, or rotary sails, or sails that are raised to high altitudes. The second idea refers to what can be practically done on board ships to reduce pollution. This includes, improving the quality of fuel or lowering its sulphur content, improving the construction process or methods for ship hulls or engines.

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WELDING ALUMINUM ALLOY INVESTIGATIONS WITH EDDY-CURRENT DEFECTOSCOPY METHOD

Constantin DUMITRACHE; Mihaela BARHALESCU; Adrian SABAU

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The purpose of this paper is to make investigations at aluminum alloy welded structures in condition of normal welding (TIG-tungsten inert gas welding), and the same procedure but arc-weld is disrupting and makes void spaces into the weld bead. It is very known that aluminum reacts with oxygen despite of using protective argon atmosphere and will cause porosity which decrease strength and ductility.

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LINGUISTIC ANALYSIS AS A SOURCE OF TEACHING/LEARNING MATERIALS DESIGN

Nadiya DEMYDENKO

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The paper focuses on the methods and techniques of composing teaching/learning materials for marine engineers who are trained to receive Bachelor Degree. Maritime English language materials meant for communicative activities are linguistically oriented, authentic and highly motivating from the professional point of view. These materials are based on the arrangement principles of English-Russian Dictionary of Maritime Terms developed at ESP department of the Academy. The paper suggests terminographic essays for the language classroom activities as a means of practical work with engineering terms.

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A NEW INNOVATIVE HIGHLY EFFICIENT TWO COMPRESSION STAGES TURBOCHARGER-INVENTION PATENT PRESENTATION

Ioan CALIMANESCU; Lucian GRIGORESCU

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The present paperwork is meant to present a new innovative and highly efficient solution for a two compression stages which is the object of a brand new invention Patent. This paperwork is proving that the proposed high efficiency turbocharger is a viable solution to be adopted when the engine manufacturer is looking for extrapower from any existing type of combustion engine. The solution is simple, elegant and compact, which can be realized with the existing technology. By analyzing the numerical simulation we may pull the conclusion that the existence of the second compression stage rotor is greatly improving the output pressure of the device and is consistently shortening the reaction time.

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TECHNOLOGICAL ASPECTS OF THE INDUCTION HARDENING OF INTERNAL ROTARY SURFACES OF SHIP JOINTS

Bohos APRAHAMIAN; Maik STREBLAU; Vladimir SHTARBAKOV; Dimitar STAVREV

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The surface hardening by induction heating has many advantages over other methods of conventional thermal processing. It is known that this method is applied to achieve high hardness in the surface layer maintaining a resilient core. The implementation of the required thermal cycle depends both on the characteristics of the material undergoing processing and of the parameters of the system of induction impact. Some difficulties arise in high-frequency hardening of internal cylindrical surfaces of ferromagnetic joints with relatively small diameters, as there is a pronounced the Ring effect, leading to displacement of the eddy currents in the detail and to reduce the efficiency, and hence the quality of the products. The purpose of this work is to study the technological aspects of the induction hardening of internal rotary surfaces.

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STRUCTURAL ANALYSIS ON SPARKING SUPERFICIAL LAYERS WITH TUNGSTEN AND TITANIUM CARBIDES ELECTRODES

Mihaela BARHALESCU; Constantin DUMITRACHE; Adrian SABAU

4/1/2012

Marine sciences and engineering; Renewable energies; Marine renewable energies and Sustenability; Advanced technologies for MET; Climate changes

The paper shows some theoretical and experimental aspects with reference to the superficial processing using electrical sparking. The tests objective was the superficial processing through sparking process on alloy and non alloy steel samples using a sinter carbide W and Ti electrodes type WCo8, Ti15Co6. The paper shows metallographic analysis on sparking superficial layers. The analysis was made on NEOPHOT 32 (special microscope) and MC-2 and MC-6 (metallographic microscope). Optic metallographic analyses of sparking superficial layers obtained using “hard” carbide electrodes W and Ti sinterysed had as a result a white layer resistant at normal chemical reactive attack on sample surface. Under this layer a transition zone will form which is obvions at hardened proofs and under “hard” working condition.

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