Journal of Marine Technology and Environment 2022 Vol. 1

This paper is a part of the efforts done in order to analyse the performance of vapour compression refrigeration cycles. These technologies are used with a high rate in marine refrigeration and are responsible for important amounts of energy consumptions. The obtained results are indicating the fact that the performance of the cycle is decreased when increasing the condensation temperature and keeping constant the evaporation temperature. Gains in the performance are obtained when degrees of superheating and sub cooling are increased, resulting that the cycle with superheating and sub cooling is superior to the one without these two processes. Ammonia or (R717) is a refrigerant often used on board the ships due to its very good thermodynamic properties. Moreover, the concern regarding the environment and the fact that ammonia is a natural refrigerant, offers to this refrigerant the chance to be adopted in the future plants, on board of new ships. The performance of an ammonia based cycle is discussed in terms of coefficient of performance (COP) and exergy efficiency, the theory of the first and second laws of thermodynamics being fundamental.

This study is intended to investigate producibility of functionally graded AlB2/Al composites which are used in the manufacture of ship machinery parts. AlB2 particles have been spontaneously formed in liquid matrix as reinforcement. A semi-solid composite (Al(l) - AlB2(s)) prepared at 850°C was solidified under a centrifugal force to grade functionally. The properties of composite materials such as hardness and microstructure have been examined. This research provided the following findings, AlB2 particles can be successfully synthesized with in situ reaction technique in molten aluminum. It was determined that the hardness value of the composites increases with increasing AlB2 reinforcement content within matrix. Functionally graded AlB2/Al composite materials can be successfully produced with centrifugal casting technique. It is also determined that AlB2 reinforcement ratio of the composite materials ranged from 0 to 7 vol. %. In addition, it was observed that the hardness values of the composites increased with the addition of reinforcement ratio.

The behaviour of a metallic material subjected to the action of a variable stress (which generates mechanical stresses in the material with variable intensities over time) differs significantly from that corresponding to the action of constant or monotonically increasing stresses which do not change in intensity over time or which increase continuously in intensity as time passes), its rupture may occur even if the intensity of the mechanical stresses generated during the stress σ is less than the tensile strength of the material Rm. The article studied the static and dynamic behaviour (fatigue) of an equipment consisting of a jacket and two semi-helical lids.

As well known, the day of 11 March 2020 will remain in the history as the day in which The World Health Organization (WHO) has declared COVID-19 a pandemic. Under these circumstances, the international higher education was forced to remove the campus activities in online. Constanta Maritime University is one of the universities across the world which moved the educational process from face- to- face to online learning. This was a challenging task for the academic, managing and technical administration and for the students, as well. This paper focuses on the disciplined entitled Thermodynamics 1, encountered in the curricula of the Electromechanics Faculty, Constanta Maritime University. The paper describes the steps done during the online education along the semester, both by students and lecturers. At the end of the semester, students and lecturers had to face another challenge: the online examination. Since in the new conditions, the students had to gain the same knowledge as during the classic educational process, we are providing the results obtained by our students. Their exam was scheduled on June 26, 2020. The number of students attending the online examination was 108. The online report for the examination, available on the online platform of the university, indicates that online 17 students were not able to pass the examination (grade 5). The same chart data shows that 19 students have obtained grades in the range (8,00- 8,50), while 2 students obtained grades in the range (9, 50- 10,00). These results are considered to be encouraging for lecturers and students. This type of examination it is seen as a potential long term examination manner, given its benefits: online generation of the test, online verification and not last, transparency.

This paper presents the results of an innovative approach in the underwater domain of research related to the identification, classification and recognition of maritime targets using acoustic data processed. The “Acoustic Signature” is specific to each target type; it is usually produced by the vibration of the propulsion system of surface vessels caused by their radiation into the water. Therefore, the processing of the frequencies generated by these vibrations is essential for the analysis and the classification of different target type. The purpose of this study is to build an alternative method to identify and classify targets with passive sonars using the TPWS (Two - Pass Split - Windows) filter. In this process, the signal generated by the target is processed in time frequency domain. Then a TPSW algorithm is applied in the frequency domain to reduce the background noise and enhance the frequency lines of the target noise. Finally, an artificial intelligence model is applied to classify targets, taking as inputs the narrowband and the broadband analysis. This classification is based on deep learning process, relied on the training, validation, and test phases in order to enhance the accuracy and reduce the loss. Our results showed that the suggested method is accurate (appx 83.5% SNR = 0db), depending essentially on the signal/noise ratio.

In the conditions of normal operation of ships, due to the release of heat from various machines and people, the increase in humidity as well as due to various releases of gases from on-board systems or goods being transported, the air in the rooms it degrades, requiring its replacement and processing. In the following we will present the issue associated with ensuring the comfort parameters on board ships, a matter regulated by international provisions on ensuring living conditions for crews - International Code for Safety Management and Pollution Prevention (ISM Code).

Gеnеrally, icеbrеakеrs havе bееn built as nuclеar-powеrеd Arctic ships, but for rеasons rеlatеd to thе protеction of thе еnvironmеnt, and еspеcially thе Arctic еnvironmеnt, this trеnd has bеgun to changе. A nuclеar icеbrеakеr is a typе of nuclеar-powеrеd motor vеssеl for usе in icе-covеrеd watеrs. In wintеr, thе icе along thе North Sеa routе variеs in thicknеss from 1.2 to 2.0 mеtеrs. Thе icе in thе cеntral parts of thе Arctic Ocеan has an avеragе thicknеss of 2.5 mеtеrs. Nuclеar icеbrеakеrs can pass through this icе at spееds of up to 10 knots (19 km/h). In icе-frее watеrs thе maximum spееd of icеbrеakеrs is up to 21 knots (39 km).

In the study, PSC inspections data performed in Paris MoU between the years 2016 and 2020 were analysed with the purpose of providing reasonable decision supports for key stakeholders such as ship operators, national and international authorities, cargo owners and classification societies in terms of enhancing safety on board ship and minimizing sub-standard ships in maritime transport. The probabilistic analysis is conducted with the help of Event Tree Analysis (ETA) method on deficiency risk areas respect to the number of deficiencies in each area. In the analysis, the deficiency risk areas are prioritized respect to the different combination of ship type and ship age. In the analysis made on the inspections data, it was found that the number of deficiencies detected under each relevant main item (deficiency risk areas) show significant variation for type of ship and age of ship. With the conducted analysis, in the study, it is aimed to contribute to the more effective inspection by focusing on certain deficiency risk areas in line with the ship type and ship age in the ship inspections.

Maritime education covers the main seafarer’s education, but after emerging of a new profession in the maritime sector it has started to cover some other aspects of the industry such as port management, fleet management, shipyard management, etc. Additionally, the exponential development of technology enforced education planners to review and revise their programs frequently to meet the expectation of new technological and management structures. Realizing this situation, academicians in the maritime field should understand the new posture of the maritime industry and define their role and missions in the light of the new requirements of the maritime sector. This research aims to investigate the new role and the missions of maritime education institutes considering developments in science and technology in the next decade. In the first step, it is important to understand technological development affecting the maritime sector and imagine the future structure and requirements of the sector. Based on the results of this study a comprehensive study must be done to define what must be done in the education system to respond to new requirements. This research must be exhaustive and detailed. The problem areas are clearly defined and summarized as findings at the end of this step. These requirements must be adopted with academic programs. Adaptation of these corrective proposals to existing academic programs should be discussed considering how these new proposals are associated with the existing programs and/or matched with other related programs This study will assist the academicians and researchers who work on the development of the maritime education and training system using the results of this study.

Purpose: In the last few decades, there has been an increasing growth in research into the use of positioning technologies in open environments. Most of the technologies developed for outdoor environments are used successfully, however, they cannot be considered as fully successful indoors. In this context, various technologies based on Radio Frequency, Infrared, Ultrasound, Magnetic, Optical, and computer vision are proposed to improve positioning indoors. In addition to their individual use, it is also seen in hybrid applications. In particular, Radio Frequency based technologies have potential use in shipyard environments. For this purpose, technologies such as Bluetooth, Ultra broadband, Wireless Sensor Network, Wireless Local Area Network, Radio Frequency Recognition and Near Field Communication are seen as suitable technology options for shipyards. The indoor positioning system is a technology that has the potential to significantly improve work efficiency and safety in the shipyard area. It is difficult to achieve a successful digital transformation of the complex shipyard environment without identifying an Indoor positioning technology for the shipyard. In this study, it is aimed to design a positioning technology that will be most appropriate for the shipyard. Methodology: This paper analyses the challenges for the selection of Indoor positioning system for shipyards in evaluating Indoor-positioning technologies. The methodology followed in this study is a comprehensive comparative analysis of existing IPS technologies on how to digitize shipyards. This article provides an advanced assessment of indoor positioning technologies and their use in the challenging shipyard site. In this context, it provides an evaluation framework for different positioning measures such as accuracy, coverage, scalability, cost, privacy and usability of technologies that can be used within the scope of IPS. Results: The work carried out here on indoor positioning systems and components makes a significant contribution to the shipyard industry. Because it has a great impact on the suitability of technologies, especially in relation to the shipyard environment. Both the evaluation model and solution method, and the Bluetooth-based positioning technology, which stands out at the end of the evaluation, are important contributions of the study. Conclusion: To determine which indoor positioning systems are more suitable for the shipyard environment, both a detailed analysis of the shipyard environment and an evaluation were made to select the most suitable technology. The comparison was made based on observations of the shipyard site and the available literature on the field. This article makes important contributions to future shipyards' application of positioning technologies.

This paper presents the study of a jib crane from a general cargo ship. There are numerous different types of vessels operating today in the various markets worldwide. Besides, thousands of cargo vessel ply the world’s oceans and seas each year, handling the bulk of international trade. The cranes from cargo ship is required to be adequate stability and strength for each load. All cranes from vessel are mounted on deck of the ship. Having regard in particular to the stress induced at its mounting or fixing points, adequately ballasted, securely anchored and supported by outriggers as necessary to ensure its stability when lifting. A jib from a crane from cargo ship is a type of overhead lifting device that is often used in a smaller work cell area for repetitive and unique lifting tasks. The extreme values of the stresses and reaction forces are determined by the finite element method. In this manuscript, the design of the cargo ship and the study of a jib crane are made using NX software from Siemens.

In the context of the judicious use of natural resources, the obtaining of the mechanical, electrical or protection or resistance characteristics necessary for their use and the economic optimization, it is necessary to study new methods. The method of deposition of surface layers with the help of pulsed lasers offers new directions of development. The deposition of aluminum or copper on cheap basic materials is economically justified but it is necessary to study their corrosion behavior. The study was performed on a 1C45 base material and on samples of the same material with a surface layer of aluminum and copper. The immersion of the samples for a period of 195 days provided measurable results which led to conclusions on the behavior of these materials in the marine environment. Contrary to expectations, the corrosion was manifested in copper, and aluminum showed a high protection capacity. However, the effects of the environment on the strength of the treated surface must also be taken into account during use.